BACKGROUND:Many studies have suggested that one possible etiology of mild cognitive impairment is small vessel cerebrovascular disease,which is associated with small subcortical infarcts and white matter abnormalities...BACKGROUND:Many studies have suggested that one possible etiology of mild cognitive impairment is small vessel cerebrovascular disease,which is associated with small subcortical infarcts and white matter abnormalities.These white matter changes have been detected as white matter hyperintensity(WMH) using magnetic resonance imaging.WMH may be associated with frontal lobe dysfunction. OBJECTIVE:To examine white matter changes in mild cognitive impairment patients of different subtypes,and to evaluate the correlation between white matter changes and neuropsychological characteristics,demographic information,vascular risk factors,and mild cognitive impairment subtypes. DESIGN,TIME AND SETTING:The neurophysiological,comparison study was performed at the Department of Neurology Memory Clinic,Ulsan University Hospital,South Korea,between March 2007 and March 2008. PARTICIPANTS:Out of a total of 83 subjects with clinically diagnosed mild cognitive impairment at the out-patient clinic,3 subjects with severe WMH were excluded.A total of 80 subjects were included in this study.No patients suffered from cognitive impairment induced by neurological diseases,mental disorders,or somatic diseases.In accordance with magnetic resonance imaging results,the patients were assigned to two subtypes:56 subjects without WMH and 24 subjects with WMH. METHODS:All patients were subjected to a standard neuropsychological battery using the Korean version of the Mini-Mental State Examination,Clinical Dementia Rating,and comprehensive Seoul Neuropsychological Screening Battery.The Clinical Dementia Rating reflected general cognitive function of patients.Results from the Seoul Neuropsychological Screening Battery reflected attention,language function,visuospatial function,verbal memory,nonverbal memory,long-term memory,and frontal/executive function.Magnetic resonance imaging was used to map changes in the brain. MAIN OUTCOME MEASURES:The association between various white matter changes and neuropsychological characteristics,demographic information,vascular risk factors,and mild cognitive impairment subtypes was measured,based primarily on neuropsychological profiles using statistical methods. RESULTS:WMH was significantly associated with neuropsychological characteristics in MCI patients(P<0.05 or P<0.01),in particular with frontal/executive dysfunction.WMH was significantly correlated with age(P=0.022) and vascular risk factors(P=0.006),independent of gender and MCI subtypes. CONCLUSION:WMH was significantly associated with frontal/executive dysfunction in mild cognitive impairment.展开更多
BACKGROUND Several studies have reported that the walking trail making test(WTMT)completion time is significantly higher in patients with developmental coordination disorders and mild cognitive impairments.We hypothes...BACKGROUND Several studies have reported that the walking trail making test(WTMT)completion time is significantly higher in patients with developmental coordination disorders and mild cognitive impairments.We hypothesized that WTMT performance would be altered in older adults with white matter hyperintensities(WMH).AIM To explore the performance in the WTMT in older people with WMH.METHODS In this single-center,observational study,25 elderly WMH patients admitted to our hospital from June 2019 to June 2020 served as the WMH group and 20 participants matched for age,gender,and educational level who were undergoing physical examination in our hospital during the same period served as the control group.The participants completed the WTMT-A and WTMT-B to obtain their gait parameters,including WTMT-A completion time,WTMT-B completion time,speed,step length,cadence,and stance phase percent.White matter lesions were scored according to the Fazekas scale.Multiple neuropsychological assessments were carried out to assess cognitive function.The relationships between WTMT performance and cognition and motion in elderly patients with WMH were analyzed by partial Pearson correlation analysis.RESULTS Patients with WMH performed significantly worse on the choice reaction test(CRT)(0.51±0.09 s vs 0.44±0.06 s,P=0.007),verbal fluency test(VFT,14.2±2.75 vs 16.65±3.54,P=0.012),and digit symbol substitution test(16.00±2.75 vs 18.40±3.27,P=0.010)than participants in the control group.The WMH group also required significantly more time to complete the WTMT-A(93.00±10.76 s vs 70.55±11.28 s,P<0.001)and WTMT-B(109.72±12.26 s vs 82.85±7.90 s,P<0.001).WTMT-A completion time was positively correlated with CRT time(r=0.460,P=0.001),while WTMT-B completion time was negatively correlated with VFT(r=-0.391,P=0.008).On the WTMT-A,only speed was found to statistically differ between the WMH and control groups(0.803±0.096 vs 0.975±0.050 m/s,P<0.001),whereas on the WTMT-B,the WMH group exhibited a significantly lower speed(0.778±0.111 vs 0.970±0.053 m/s,P<0.001)and cadence(82.600±4.140 vs 85.500±5.020 steps/m,P=0.039),as well as a higher stance phase percentage(65.061±1.813%vs 63.513±2.465%,P=0.019)relative to controls.CONCLUSION Older adults with WMH showed obviously poorer WTMT performance.WTMT could be a potential indicator for cognitive and motor deficits in patients with WMH.展开更多
BACKGROUND Major depression disorder(MDD)constitutes a significant mental health concern.Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults,wi...BACKGROUND Major depression disorder(MDD)constitutes a significant mental health concern.Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults,with a corresponding increased risk of suicide.In studying brain dysfunction associated with MDD in adolescents,research on brain white matter(WM)is sparse.Some researchers even mistakenly regard the signals generated by the WM as noise points.In fact,studies have shown that WM exhibits similar blood oxygen level-dependent signal fluctuations.The alterations in WM signals and their relationship with disease severity in adolescents with MDD remain unclear.AIM To explore potential abnormalities in WM functional signals in adolescents with MDD.METHODS This study involved 48 adolescent patients with MDD and 31 healthy controls(HC).All participants were assessed using the Patient Health Questionnaire-9 Scale and the mini international neuropsychiatric interview(MINI)suicide inventory.In addition,a Siemens Skyra 3.0T magnetic resonance scanner was used to obtain the subjects'image data.The DPABI software was utilized to calculate the WM signal of the fractional amplitude of low frequency fluctuations(fALFF)and regional homogeneity,followed by a two-sample t-test between the MDD and HC groups.Independent component analysis(ICA)was also used to evaluate the WM functional signal.Pearson’s correlation was performed to assess the relationship between statistical test results and clinical scales.RESULTS Compared to HC,individuals with MDD demonstrated a decrease in the fALFF of WM in the corpus callosum body,left posterior limb of the internal capsule,right superior corona radiata,and bilateral posterior corona radiata[P<0.001,family-wise error(FWE)voxel correction].The regional homogeneity of WM increased in the right posterior limb of internal capsule and left superior corona radiata,and decreased in the left superior longitudinal fasciculus(P<0.001,FWE voxel correction).The ICA results of WM overlapped with those of regional homogeneity.The fALFF of WM signal in the left posterior limb of the internal capsule was negatively correlated with the MINI suicide scale(P=0.026,r=-0.32),and the right posterior corona radiata was also negatively correlated with the MINI suicide scale(P=0.047,r=-0.288).CONCLUSION Adolescents with MDD involves changes in WM functional signals,and these differences in brain regions may increase the risk of suicide.展开更多
Objective:To explore whether maternal stress exposure during pregnancy impairs cognitive function and white matter ultrastructure in offspring mice.Methods:The parent rats were divided into two groups:pressure exposur...Objective:To explore whether maternal stress exposure during pregnancy impairs cognitive function and white matter ultrastructure in offspring mice.Methods:The parent rats were divided into two groups:pressure exposure group(group PE)and control group(group C),and the positive date of vaginal smear of female SD rats was day 0 of gestation.Female mice in group PE were exposed to binding pressure(3 times/day)on day 14-20 of gestation for 45 min-1 h/time.Behavioral tests(Morris water maze and Y maze)were performed on 1-month-old offspring mice followed by cardiac perfusion of fixed brain specimens and placement in mixed fixative solution.The total volume of white matter,total length and volume of myelinated nerve fibers and total length and volume of myelin sheath were calculated using modern stereoscopic methods,and the inner and outer diameter and inner and outer circumference of the myelin sheath were analyzed.Results:1)Behavioral tests:compared with the group C,the average latency of the 3th and 4th day in the group PE were significantly prolonged,the percentage of the resting time in the quadrant of the platform and the frequency of acrossing the effective area of platform in the fifth day of space exploration experiment were significantly reduced of Morris water maze test,and visiting distance,duration and numbers in novel arm significantly increased of Y-maze test(P<0.05).2)Compared with group C,the total volume of white matter,total length of myelinated nerve fibers,total volume of myelinated nerve fibers and myelin sheath in the group PE were significantly reduced(P<0.05),the inner diameter and outer diameter of myelin sheath decreased significantly(P<0.05),and the inner perimeter,outer perimeter and inner and outer perimeter differences increased significantly(P<0.05).3)There was a correlation between behavioral test results and white matter ultrastructure measurement results.Conclusions:Maternal stress exposure during pregnancy could impair the cognitive function and white matter and its ultrastructure in the offspring,and there was a correlation between decreased cognitive function and white matter damages.展开更多
A mathematical model was developed to predict the risk of having a stroke as a person ages. The age component was derived from the concept that the change in risk of stroke with age is a function of the current risk o...A mathematical model was developed to predict the risk of having a stroke as a person ages. The age component was derived from the concept that the change in risk of stroke with age is a function of the current risk of developing a stroke. This equation modeled the trend with age reported in the literature for two different data sets with R<sup>2</sup> values of 0.97 or better for both men and women. A second equation of a similar nature was developed to predict the accumulation of white matter hyperintensities, WMH, as a person ages. It appears that each equation includes a set of common risk factors. This set of common risk factors allows an individual’s risk for stroke to be based on measured WMH. A third equation links WMH with the risk of developing a stroke. This equation allows an individual to use measured WMH from brain scans to predict the future risk of developing a stroke. In theory, a person with a relatively high measurement of WMH can project future risk for stroke with age and use counter measures such as exercise and medications to keep other risk factors low as a person continues to age.展开更多
Objective Exosomal long noncoding RNAs(lnc RNAs) are the key to diagnosing and treating various diseases. This study aimed to investigate the diagnostic value of plasma exosomal lnc RNAs in white matter hyperintensiti...Objective Exosomal long noncoding RNAs(lnc RNAs) are the key to diagnosing and treating various diseases. This study aimed to investigate the diagnostic value of plasma exosomal lnc RNAs in white matter hyperintensities(WMH).Methods We used high-throughput sequencing to determine the differential expression(DE) profiles of lnc RNAs in plasma exosomes from WMH patients and controls. The sequencing results were verified in a validation cohort using q RT-PCR. The diagnostic potential of candidate exosomal lnc RNAs was proven by binary logistic analysis and receiver operating characteristic(ROC) curves. The diagnostic value of DE exo-lnc RNAs was determined by the area under the curve(AUC). The WMH group was then divided into subgroups according to the Fazekas scale and white matter lesion site, and the correlation of DE exo-lnc RNAs in the subgroup was evaluated.Results In our results, four DE exo-lnc RNAs were identified, and ROC curve analysis revealed that exolnc_011797 and exo-lnc_004326 exhibited diagnostic efficacy for WMH. Furthermore, WMH subgroup analysis showed exo-lnc_011797 expression was significantly increased in Fazekas 3 patients and was significantly elevated in patients with paraventricular matter hyperintensities.Conclusion Plasma exosomal lnc RNAs have potential diagnostic value in WMH. Moreover, exolnc_011797 is considered to be a predictor of the severity and location of WMH.展开更多
Objective:The frontal lobe may be involved in circuits associated with depression,apathy,aggression,and other psychiatric symptoms.Although white matter changes(WMC)are related to the severity of behavioral and psycho...Objective:The frontal lobe may be involved in circuits associated with depression,apathy,aggression,and other psychiatric symptoms.Although white matter changes(WMC)are related to the severity of behavioral and psychological symptoms of dementia(BPSD)in patients with Alzheimer’s disease(AD),it is unclear which part of the WMC may play the most important role in BPSD.This study was designed to investigate the relationship between the location of WMC and the severity of BPSD in AD patients.Methods:Among patients diagnosed with Alzheimer’s disease between 2009 and2014,387 patients were retrospectively reviewed after those with pre‐existing organic brain syndrome,psychiatric diseases,or toxic‐metabolic encephalopathy were excluded.Patients’demographic and laboratory data,WMC measured with brain computed tomography and scored using the age‐related white matter changes(ARWMC)scale,and neuropsychological tests,including the cognitive abilities screening instrument(CASI),the Mini‐Mental State Examination(MMSE),the clinical dementia rating scale with sum‐box(CDR‐SB),and the neuropsychiatric inventory(NPI)were analyzed.Results:There was no significant difference in the NPI between patients with and without a history of stroke,hypertension,and diabetes.No significant difference in the NPI was identified between different sexes or different Apolipoprotein E(APOE)alleles.The NPI score was significantly correlated with the duration of education(r=–0.4515,P=0.0172),CASI(r=–0.2915,P<0.0001),MMSE(r=–0.8476,P<0.0001),and CDR‐SB(r=2.2839,P<0.0001).WMC in the right frontal lobe showed a significant difference in NPI in comparison to those without WMC(P=0.0255).After adjusting for age,duration of education,and CASI,WMC in the right frontal lobe remained significantly associated with the NPI score(β=3.8934,P=0.042).Conclusions:WMC involving the right frontal lobe may play an important role in the BPSD in AD patients during their dementia diagnosis.Further studies are necessary to confirm whether controlling the risk factors of WMC can slow the progression of BPSD.展开更多
Applications of multifractal analysis to white matter structure changes on magnetic resonance imaging(MRI) have recently received increasing attentions. Although some progresses have been made, there is no evident stu...Applications of multifractal analysis to white matter structure changes on magnetic resonance imaging(MRI) have recently received increasing attentions. Although some progresses have been made, there is no evident study on applying multifractal analysis to evaluate the white matter structural changes on MRI for Alzheimer's disease(AD) research. In this paper, to explore multifractal analysis of white matter structural changes on 3D MRI volumes between normal aging and early AD, we not only extend the traditional box-counting multifractal analysis(BCMA) into the 3D case, but also propose a modified integer ratio based BCMA(IRBCMA) algorithm to compensate for the rigid division rule in BCMA. We verify multifractal characteristics in 3D white matter MRI volumes. In addition to the previously well studied multifractal feature,△α, we also demonstrated △ f as an alternative and effective multifractal feature to distinguish NC from AD subjects.Both △α and △ f are found to have strong positive correlation with the clinical MMSE scores with statistical significance.Moreover, the proposed IRBCMA can be an alternative and more accurate algorithm for 3D volume analysis. Our findings highlight the potential usefulness of multifractal analysis, which may contribute to clarify some aspects of the etiology of AD through detection of structural changes in white matter.展开更多
Hills Like White Elephants is a short story by Ernest Hemingway.It is a story about an American man and a pregnant girl.As the protagonist,Jig is considered as a submissive woman who has no definite views of her own.T...Hills Like White Elephants is a short story by Ernest Hemingway.It is a story about an American man and a pregnant girl.As the protagonist,Jig is considered as a submissive woman who has no definite views of her own.This paper attempts to analyze the changes of Jig's inner thought during the forty minutes of waiting the train.In addition to how the girl has grown up from a weak and dependent character into a brave and independent female after the painful struggle in the helpless and hopeless states under the great pressure of the man.展开更多
A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial ...A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial cells into neurons in the central nervous system through ectopically expressing neural transcriptional factors in glial cells. Previous studies have been focusing on glial cells in the grey matter such as the cortex and striatum, but whether glial cells in the white matter can be reprogrammed or not is unknown. To address this fundamental question, we express NeuroD1 in the astrocytes of both grey matter(cortex and striatum) and white matter(corpus callosum) to investigate the conversion efficiency, neuronal subtypes, and electrophysiological features of the converted neurons. We discover that NeuroD1 can efficiently reprogram the astrocytes in the grey matter into functional neurons, but the astrocytes in the white matter are much resistant to neuronal reprogramming. The converted neurons from cortical and striatal astrocytes are composed of both glutamatergic and GABAergic neurons, capable of firing action potentials and having spontaneous synaptic activities. In contrast, the few astrocyte-converted neurons in the white matter are rather immature with rare synaptic events. These results provide novel insights into the differential reprogramming capability between the astrocytes in the grey matter versus the white matter, and highlight the impact of regional astrocytes as well as microenvironment on the outcome of glia-toneuron conversion. Since human brain has large volume of white matter, this study will provide important guidance for future development of in vivo glia-to-neuron conversion technology into potential clinical therapies. Experimental protocols in this study were approved by the Laboratory Animal Ethics Committee of Jinan University(approval No. IACUC-20180321-03) on March 21, 2018.展开更多
With improvements in care of at-risk neonates, more and more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. Computed...With improvements in care of at-risk neonates, more and more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. Computed tomography, ultrasound, and conventional magnetic resonance imaging are helpful to diagnose brain injury, but cannot quantify white matter damage. In this study, ten full-term infants without brain injury and twenty-two full-term neonates with hypoxic-ischemic encephalopathy(14 moderate cases and 8 severe cases) underwent diffusion tensor imaging to assess its feasibility in evaluating white matter damage in this condition. Results demonstrated that fractional anisotropy, voxel volume, and number of fiber bundles were different in some brain areas between infants with brain injury and those without brain injury. The correlation between fractional anisotropy values and neonatal behavioral neurological assessment scores was closest in the posterior limbs of the internal capsule. We conclude that diffusion tensor imaging can quantify white matter injury in neonates with hypoxic-ischemic encephalopathy.展开更多
Carnosine is a dipeptide that scavenges free radicals,inhibits inflammation in the central nervous system,and protects against ischemic and hypoxic brain damage through its anti-oxidative and anti-apoptotic actions.Th...Carnosine is a dipeptide that scavenges free radicals,inhibits inflammation in the central nervous system,and protects against ischemic and hypoxic brain damage through its anti-oxidative and anti-apoptotic actions.Therefore,we hypothesized that carnosine would also protect against white matter damage caused by subcortical ischemic injury.White matter damage was induced by right unilateral common carotid artery occlusion in mice.The animals were treated with 200,500 or 750 mg/kg carnosine by intraperitoneal injection 30 minutes before injury and every other day after injury.Then,37 days later,Klüver-Barrera staining,toluidine blue staining and immunofluorescence staining were performed.Carnosine(200,500 mg/kg) substantially reduced damage to the white matter in the corpus callosum,internal capsule and optic tract,and it rescued expression of myelin basic protein,and alleviated the loss of oligodendrocytes.However,carnosine at the higher dose of 750 mg/kg did not have the same effects as the 200 and 500 mg/kg doses.These findings show that carnosine,at a particular dose range,protects against white matter damage caused by chronic cerebral ischemia in mice,likely by reducing oligodendroglial cell loss.展开更多
The Jiaozhou Bay is characterized by heavy eutrophication that is associated with intensive anthropogenic activities. Four core sediments from the Jiaozhou Bay are analyzed using bulk technologies, including sedimenta...The Jiaozhou Bay is characterized by heavy eutrophication that is associated with intensive anthropogenic activities. Four core sediments from the Jiaozhou Bay are analyzed using bulk technologies, including sedimentary total organic carbon(TOC), total nitrogen(TN), the stable carbon(δ^(13)C) and nitrogen(δ^(15) N) isotopic composition to obtain the comprehensive understanding of the source and composition of sedimentary organic matter and further shed light on the environmental changes of the Jiaozhou Bay on a centennial time scale.Results suggest that the TOC and TN concentrations increase in the upper core, having indicated a probable eutrophication process since the 1920 s in the inner bay and the 2000 s in the bay mouth. The TOC and TN concentrations outside the bay have also changed since 1916 owing to the variation of terrigenous input.Considering TOC/TN ratio, δ^(13) C and δ^(15) N, it can be concluded there is a mixture of terrigenous and marine organic matter sources in the study area. A simple two end-member(terrigenous and marine) mixing model usingδ^(13) C indicats that 45%–79% of TOC in the Jiaozhou Bay is from the marine source. The environmental changes of the Jiaozhou Bay are recorded by geochemical proxies, which are influenced by the intensive anthropogenic activities(e.g., extensive use of fertilizers, and discharge of sewage) and climate changes(e.g., rainfall).展开更多
Subcortical ischemic white matter injury(SIWMI),pathological correlate of white matter hyperintensities or leukoaraiosis on magnetic resonance imaging,is a common cause of cognitive decline in elderly.Despite its high...Subcortical ischemic white matter injury(SIWMI),pathological correlate of white matter hyperintensities or leukoaraiosis on magnetic resonance imaging,is a common cause of cognitive decline in elderly.Despite its high prevalence,it remains unknown how various components of the white matter degenerate in response to chronic ischemia.This incomplete knowledge is in part due to a lack of adequate animal model.The current review introduces various SIWMI animal models and aims to scrutinize their advantages and disadvantages primarily in regard to the pathological manifestations of white matter components.The SIWMI animal models are categorized into 1)chemically induced SIWMI models,2)vascular occlusive SIWMI models,and 3)SIWMI models with comorbid vascular risk factors.Chemically induced models display consistent lesions in predetermined areas of the white matter,but the abrupt evolution of lesions does not appropriately reflect the progressive pathological processes in human white matter hyperintensities.Vascular occlusive SIWMI models often do not exhibit white matter lesions that are sufficiently unequivocal to be quantified.When combined with comorbid vascular risk factors(specifically hypertension),however,they can produce progressive and definitive white matter lesions including diffuse rarefaction,demyelination,loss of oligodendrocytes,and glial activation,which are by far the closest to those found in human white matter hyperintensities lesions.However,considerable surgical mortality and unpredictable natural deaths during a follow-up period would necessitate further refinements in these models.In the meantime,in vitro SIWMI models that recapitulate myelinated white matter track may be utilized to study molecular mechanisms of the ischemic white matter injury.Appropriate in vivo and in vitro SIWMI models will contribute in a complementary manner to making a breakthrough in developing effective treatment to prevent progression of white matter hyperintensities.展开更多
The spinal cord is composed of gray matter and white matter.It is well known that the properties of these two tissues differ considerably.Spinal diseases often present with symptoms that are caused by spinal cord comp...The spinal cord is composed of gray matter and white matter.It is well known that the properties of these two tissues differ considerably.Spinal diseases often present with symptoms that are caused by spinal cord compression.Understanding the mechanical properties of gray and white matter would allow us to gain a deep understanding of the injuries caused to the spinal cord and provide information on the pathological changes to these distinct tissues in several disorders.Previous studies have reported on the physical properties of gray and white matter,however,these were focused on longitudinal tension tests.Little is known about the differences between gray and white matter in terms of their response to compression.We therefore performed mechanical compression test of the gray and white matter of spinal cords harvested from cows and analyzed the differences between them in response to compression.We conducted compression testing of gray matter and white matter to detect possible differences in the collapse rate.We found that increased compression(especially more than 50%compression)resulted in more severe injuries to both the gray and white matter.The present results on the mechanical differences between gray and white matter in response to compression will be useful when interpreting findings from medical imaging in patients with spinal conditions.展开更多
We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. ...We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe(superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe(postcentral and inferior parietal gyri), right temporal lobe(caudate nucleus), right occipital lobe(middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.展开更多
Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularize...Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion neurites.However,it has not been reported whether this material promotes axonal regeneration in vivo.In the present study,a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann cells.This functional scaffold promoted the directional growth and remyelination of regenerating axons.In vitro,the porcine decellularized optic nerve contained many straight,longitudinal channels with a uniform distribution,and microscopic pores were present in the channel wall.The spatial micro topological structure and extracellular matrix were conducive to the adhesion,survival and migration of neural stem cells.The scaffold promoted the directional growth of dorsal root ganglion neurites,and showed strong potential for myelin regeneration.Furthermore,we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in vivo.Four weeks later,the regenerating axons grew straight,the myelin sheath in the injured/transplanted area recovered its structure,and simultaneously,the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were reduced.Together,these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin regeneration.All procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University(approval No.SYSU-IACUC-2019-B034)on February 28,2019.展开更多
Rational fertilization is an important measure to increase crop yield and soil fertility. Through analysis,this paper aims to master the change characteristics of soil organic matter and rice yield under different fer...Rational fertilization is an important measure to increase crop yield and soil fertility. Through analysis,this paper aims to master the change characteristics of soil organic matter and rice yield under different fertilizer treatments,in order to provide an important reference for the sustainable use of soil and effective fertilization. Long-term( 19 years) rice crop rotation experiments in waterloggogenic paddy soil were conducted to investigate the change trend of crop grain yield and soil organic matter with time,reveal the dynamic characteristics and relationship between main fertility factors and crop yields using comparative analysis at three sites with conventional fertilization and non-fertilization in Guilin. The results showed that compared with previous years,the rice yield increased by 53% under the fertilization treatment and degreased by 66% under the control. Over the years,the average soil organic matter( SOM) content under fertilization treatment was 23% higher than under CK treatment. This indicates that chemical fertilizer and organic manure application can increase the rice yield and soil organic matter,and high rice yield can be attributed to the SOM increase.展开更多
Efficient strategies for neuroprotection and repair are still an unmet medical need for neurodegenerative diseases and lesions of the central nervous system.Over the last few decades,a great deal of attention has been...Efficient strategies for neuroprotection and repair are still an unmet medical need for neurodegenerative diseases and lesions of the central nervous system.Over the last few decades,a great deal of attention has been focused on white matter as a potential therapeutic target,mainly due to the discovery of the oligodendrocyte precursor cells in the adult central nervous system,a cell type able to fully repair myelin damage,and to the development of advanced imaging techniques to visualize and measure white matter lesions.The combination of these two events has greatly increased the body of research into white matter alte rations in central nervous system lesions and neurodegenerative diseases and has identified the oligodendrocyte precursor cell as a putative target for white matter lesion repair,thus indirectly contributing to neuroprotection.This review aims to discuss the potential of white matter as a therapeutic target for neuroprotection in lesions and diseases of the central nervous system.Pivot conditions are discussed,specifically multiple scle rosis as a white matter disease;spinal cord injury,the acute lesion of a central nervous system component where white matter prevails over the gray matte r,and Alzheimer's disease,where the white matter was considered an ancilla ry component until recently.We first describe oligodendrocyte precursor cell biology and developmental myelination,and its regulation by thyroid hormones,then briefly describe white matter imaging techniques,which are providing information on white matter involvement in central nervous system lesions and degenerative diseases.Finally,we discuss pathological mechanisms which interfere with myelin repair in adulthood.展开更多
基金the Korea Health 21 R&D Project, Ministry of Health and Welfare,and the Republic of Korea.No.A050079
文摘BACKGROUND:Many studies have suggested that one possible etiology of mild cognitive impairment is small vessel cerebrovascular disease,which is associated with small subcortical infarcts and white matter abnormalities.These white matter changes have been detected as white matter hyperintensity(WMH) using magnetic resonance imaging.WMH may be associated with frontal lobe dysfunction. OBJECTIVE:To examine white matter changes in mild cognitive impairment patients of different subtypes,and to evaluate the correlation between white matter changes and neuropsychological characteristics,demographic information,vascular risk factors,and mild cognitive impairment subtypes. DESIGN,TIME AND SETTING:The neurophysiological,comparison study was performed at the Department of Neurology Memory Clinic,Ulsan University Hospital,South Korea,between March 2007 and March 2008. PARTICIPANTS:Out of a total of 83 subjects with clinically diagnosed mild cognitive impairment at the out-patient clinic,3 subjects with severe WMH were excluded.A total of 80 subjects were included in this study.No patients suffered from cognitive impairment induced by neurological diseases,mental disorders,or somatic diseases.In accordance with magnetic resonance imaging results,the patients were assigned to two subtypes:56 subjects without WMH and 24 subjects with WMH. METHODS:All patients were subjected to a standard neuropsychological battery using the Korean version of the Mini-Mental State Examination,Clinical Dementia Rating,and comprehensive Seoul Neuropsychological Screening Battery.The Clinical Dementia Rating reflected general cognitive function of patients.Results from the Seoul Neuropsychological Screening Battery reflected attention,language function,visuospatial function,verbal memory,nonverbal memory,long-term memory,and frontal/executive function.Magnetic resonance imaging was used to map changes in the brain. MAIN OUTCOME MEASURES:The association between various white matter changes and neuropsychological characteristics,demographic information,vascular risk factors,and mild cognitive impairment subtypes was measured,based primarily on neuropsychological profiles using statistical methods. RESULTS:WMH was significantly associated with neuropsychological characteristics in MCI patients(P<0.05 or P<0.01),in particular with frontal/executive dysfunction.WMH was significantly correlated with age(P=0.022) and vascular risk factors(P=0.006),independent of gender and MCI subtypes. CONCLUSION:WMH was significantly associated with frontal/executive dysfunction in mild cognitive impairment.
基金Supported by The Wu Jieping Medical Foundation,No.320.6750.18456.
文摘BACKGROUND Several studies have reported that the walking trail making test(WTMT)completion time is significantly higher in patients with developmental coordination disorders and mild cognitive impairments.We hypothesized that WTMT performance would be altered in older adults with white matter hyperintensities(WMH).AIM To explore the performance in the WTMT in older people with WMH.METHODS In this single-center,observational study,25 elderly WMH patients admitted to our hospital from June 2019 to June 2020 served as the WMH group and 20 participants matched for age,gender,and educational level who were undergoing physical examination in our hospital during the same period served as the control group.The participants completed the WTMT-A and WTMT-B to obtain their gait parameters,including WTMT-A completion time,WTMT-B completion time,speed,step length,cadence,and stance phase percent.White matter lesions were scored according to the Fazekas scale.Multiple neuropsychological assessments were carried out to assess cognitive function.The relationships between WTMT performance and cognition and motion in elderly patients with WMH were analyzed by partial Pearson correlation analysis.RESULTS Patients with WMH performed significantly worse on the choice reaction test(CRT)(0.51±0.09 s vs 0.44±0.06 s,P=0.007),verbal fluency test(VFT,14.2±2.75 vs 16.65±3.54,P=0.012),and digit symbol substitution test(16.00±2.75 vs 18.40±3.27,P=0.010)than participants in the control group.The WMH group also required significantly more time to complete the WTMT-A(93.00±10.76 s vs 70.55±11.28 s,P<0.001)and WTMT-B(109.72±12.26 s vs 82.85±7.90 s,P<0.001).WTMT-A completion time was positively correlated with CRT time(r=0.460,P=0.001),while WTMT-B completion time was negatively correlated with VFT(r=-0.391,P=0.008).On the WTMT-A,only speed was found to statistically differ between the WMH and control groups(0.803±0.096 vs 0.975±0.050 m/s,P<0.001),whereas on the WTMT-B,the WMH group exhibited a significantly lower speed(0.778±0.111 vs 0.970±0.053 m/s,P<0.001)and cadence(82.600±4.140 vs 85.500±5.020 steps/m,P=0.039),as well as a higher stance phase percentage(65.061±1.813%vs 63.513±2.465%,P=0.019)relative to controls.CONCLUSION Older adults with WMH showed obviously poorer WTMT performance.WTMT could be a potential indicator for cognitive and motor deficits in patients with WMH.
基金Supported by the Suzhou Clinical Medical Center for Mood Disorders,No.Szlcyxzx202109Jiangsu Provincial Department of Science and Technology for Social Development-General Project,No.BE2022735.
文摘BACKGROUND Major depression disorder(MDD)constitutes a significant mental health concern.Epidemiological surveys indicate that the lifetime prevalence of depression in adolescents is much higher than that in adults,with a corresponding increased risk of suicide.In studying brain dysfunction associated with MDD in adolescents,research on brain white matter(WM)is sparse.Some researchers even mistakenly regard the signals generated by the WM as noise points.In fact,studies have shown that WM exhibits similar blood oxygen level-dependent signal fluctuations.The alterations in WM signals and their relationship with disease severity in adolescents with MDD remain unclear.AIM To explore potential abnormalities in WM functional signals in adolescents with MDD.METHODS This study involved 48 adolescent patients with MDD and 31 healthy controls(HC).All participants were assessed using the Patient Health Questionnaire-9 Scale and the mini international neuropsychiatric interview(MINI)suicide inventory.In addition,a Siemens Skyra 3.0T magnetic resonance scanner was used to obtain the subjects'image data.The DPABI software was utilized to calculate the WM signal of the fractional amplitude of low frequency fluctuations(fALFF)and regional homogeneity,followed by a two-sample t-test between the MDD and HC groups.Independent component analysis(ICA)was also used to evaluate the WM functional signal.Pearson’s correlation was performed to assess the relationship between statistical test results and clinical scales.RESULTS Compared to HC,individuals with MDD demonstrated a decrease in the fALFF of WM in the corpus callosum body,left posterior limb of the internal capsule,right superior corona radiata,and bilateral posterior corona radiata[P<0.001,family-wise error(FWE)voxel correction].The regional homogeneity of WM increased in the right posterior limb of internal capsule and left superior corona radiata,and decreased in the left superior longitudinal fasciculus(P<0.001,FWE voxel correction).The ICA results of WM overlapped with those of regional homogeneity.The fALFF of WM signal in the left posterior limb of the internal capsule was negatively correlated with the MINI suicide scale(P=0.026,r=-0.32),and the right posterior corona radiata was also negatively correlated with the MINI suicide scale(P=0.047,r=-0.288).CONCLUSION Adolescents with MDD involves changes in WM functional signals,and these differences in brain regions may increase the risk of suicide.
基金Shaanxi Province natural science basic research program (No.2023-JC-QN-0961)。
文摘Objective:To explore whether maternal stress exposure during pregnancy impairs cognitive function and white matter ultrastructure in offspring mice.Methods:The parent rats were divided into two groups:pressure exposure group(group PE)and control group(group C),and the positive date of vaginal smear of female SD rats was day 0 of gestation.Female mice in group PE were exposed to binding pressure(3 times/day)on day 14-20 of gestation for 45 min-1 h/time.Behavioral tests(Morris water maze and Y maze)were performed on 1-month-old offspring mice followed by cardiac perfusion of fixed brain specimens and placement in mixed fixative solution.The total volume of white matter,total length and volume of myelinated nerve fibers and total length and volume of myelin sheath were calculated using modern stereoscopic methods,and the inner and outer diameter and inner and outer circumference of the myelin sheath were analyzed.Results:1)Behavioral tests:compared with the group C,the average latency of the 3th and 4th day in the group PE were significantly prolonged,the percentage of the resting time in the quadrant of the platform and the frequency of acrossing the effective area of platform in the fifth day of space exploration experiment were significantly reduced of Morris water maze test,and visiting distance,duration and numbers in novel arm significantly increased of Y-maze test(P<0.05).2)Compared with group C,the total volume of white matter,total length of myelinated nerve fibers,total volume of myelinated nerve fibers and myelin sheath in the group PE were significantly reduced(P<0.05),the inner diameter and outer diameter of myelin sheath decreased significantly(P<0.05),and the inner perimeter,outer perimeter and inner and outer perimeter differences increased significantly(P<0.05).3)There was a correlation between behavioral test results and white matter ultrastructure measurement results.Conclusions:Maternal stress exposure during pregnancy could impair the cognitive function and white matter and its ultrastructure in the offspring,and there was a correlation between decreased cognitive function and white matter damages.
文摘A mathematical model was developed to predict the risk of having a stroke as a person ages. The age component was derived from the concept that the change in risk of stroke with age is a function of the current risk of developing a stroke. This equation modeled the trend with age reported in the literature for two different data sets with R<sup>2</sup> values of 0.97 or better for both men and women. A second equation of a similar nature was developed to predict the accumulation of white matter hyperintensities, WMH, as a person ages. It appears that each equation includes a set of common risk factors. This set of common risk factors allows an individual’s risk for stroke to be based on measured WMH. A third equation links WMH with the risk of developing a stroke. This equation allows an individual to use measured WMH from brain scans to predict the future risk of developing a stroke. In theory, a person with a relatively high measurement of WMH can project future risk for stroke with age and use counter measures such as exercise and medications to keep other risk factors low as a person continues to age.
文摘Objective Exosomal long noncoding RNAs(lnc RNAs) are the key to diagnosing and treating various diseases. This study aimed to investigate the diagnostic value of plasma exosomal lnc RNAs in white matter hyperintensities(WMH).Methods We used high-throughput sequencing to determine the differential expression(DE) profiles of lnc RNAs in plasma exosomes from WMH patients and controls. The sequencing results were verified in a validation cohort using q RT-PCR. The diagnostic potential of candidate exosomal lnc RNAs was proven by binary logistic analysis and receiver operating characteristic(ROC) curves. The diagnostic value of DE exo-lnc RNAs was determined by the area under the curve(AUC). The WMH group was then divided into subgroups according to the Fazekas scale and white matter lesion site, and the correlation of DE exo-lnc RNAs in the subgroup was evaluated.Results In our results, four DE exo-lnc RNAs were identified, and ROC curve analysis revealed that exolnc_011797 and exo-lnc_004326 exhibited diagnostic efficacy for WMH. Furthermore, WMH subgroup analysis showed exo-lnc_011797 expression was significantly increased in Fazekas 3 patients and was significantly elevated in patients with paraventricular matter hyperintensities.Conclusion Plasma exosomal lnc RNAs have potential diagnostic value in WMH. Moreover, exolnc_011797 is considered to be a predictor of the severity and location of WMH.
文摘Objective:The frontal lobe may be involved in circuits associated with depression,apathy,aggression,and other psychiatric symptoms.Although white matter changes(WMC)are related to the severity of behavioral and psychological symptoms of dementia(BPSD)in patients with Alzheimer’s disease(AD),it is unclear which part of the WMC may play the most important role in BPSD.This study was designed to investigate the relationship between the location of WMC and the severity of BPSD in AD patients.Methods:Among patients diagnosed with Alzheimer’s disease between 2009 and2014,387 patients were retrospectively reviewed after those with pre‐existing organic brain syndrome,psychiatric diseases,or toxic‐metabolic encephalopathy were excluded.Patients’demographic and laboratory data,WMC measured with brain computed tomography and scored using the age‐related white matter changes(ARWMC)scale,and neuropsychological tests,including the cognitive abilities screening instrument(CASI),the Mini‐Mental State Examination(MMSE),the clinical dementia rating scale with sum‐box(CDR‐SB),and the neuropsychiatric inventory(NPI)were analyzed.Results:There was no significant difference in the NPI between patients with and without a history of stroke,hypertension,and diabetes.No significant difference in the NPI was identified between different sexes or different Apolipoprotein E(APOE)alleles.The NPI score was significantly correlated with the duration of education(r=–0.4515,P=0.0172),CASI(r=–0.2915,P<0.0001),MMSE(r=–0.8476,P<0.0001),and CDR‐SB(r=2.2839,P<0.0001).WMC in the right frontal lobe showed a significant difference in NPI in comparison to those without WMC(P=0.0255).After adjusting for age,duration of education,and CASI,WMC in the right frontal lobe remained significantly associated with the NPI score(β=3.8934,P=0.042).Conclusions:WMC involving the right frontal lobe may play an important role in the BPSD in AD patients during their dementia diagnosis.Further studies are necessary to confirm whether controlling the risk factors of WMC can slow the progression of BPSD.
基金Project supported by the National Natural Science Foundation of China(Grant No.61271079)the Vice Chancellor Research Grant in University of Wollongongthe Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Applications of multifractal analysis to white matter structure changes on magnetic resonance imaging(MRI) have recently received increasing attentions. Although some progresses have been made, there is no evident study on applying multifractal analysis to evaluate the white matter structural changes on MRI for Alzheimer's disease(AD) research. In this paper, to explore multifractal analysis of white matter structural changes on 3D MRI volumes between normal aging and early AD, we not only extend the traditional box-counting multifractal analysis(BCMA) into the 3D case, but also propose a modified integer ratio based BCMA(IRBCMA) algorithm to compensate for the rigid division rule in BCMA. We verify multifractal characteristics in 3D white matter MRI volumes. In addition to the previously well studied multifractal feature,△α, we also demonstrated △ f as an alternative and effective multifractal feature to distinguish NC from AD subjects.Both △α and △ f are found to have strong positive correlation with the clinical MMSE scores with statistical significance.Moreover, the proposed IRBCMA can be an alternative and more accurate algorithm for 3D volume analysis. Our findings highlight the potential usefulness of multifractal analysis, which may contribute to clarify some aspects of the etiology of AD through detection of structural changes in white matter.
基金This work was supported by grants from Scientific Research Project of Health and Family Planning of Hubei Province （No. WJ2015MB056）, Natural Science Foundation of Hubei Province （No. 2015CFB572）, and Clinical Research Physician Program of Tongji Medical College, HUST.
文摘Hills Like White Elephants is a short story by Ernest Hemingway.It is a story about an American man and a pregnant girl.As the protagonist,Jig is considered as a submissive woman who has no definite views of her own.This paper attempts to analyze the changes of Jig's inner thought during the forty minutes of waiting the train.In addition to how the girl has grown up from a weak and dependent character into a brave and independent female after the painful struggle in the helpless and hopeless states under the great pressure of the man.
基金supported in part by the National Natural Science Foundation of China(Grant No.31701291 to WL,U1801681 to GC)the China Postdoctoral Science Foundation(Grant No.2016M602600 to WL)+1 种基金the Guangdong Grant ‘Key Technologies for Treatment of Brain Disorders’(Grant No.2018B030332001 to GC)the Internal Funding of Jinan University,China(Grant No.21616110 to GC)
文摘A new technology called in vivo glia-to-neuron conversion has emerged in recent years as a promising next generation therapy for neural regeneration and repair. This is achieved through reprogramming endogenous glial cells into neurons in the central nervous system through ectopically expressing neural transcriptional factors in glial cells. Previous studies have been focusing on glial cells in the grey matter such as the cortex and striatum, but whether glial cells in the white matter can be reprogrammed or not is unknown. To address this fundamental question, we express NeuroD1 in the astrocytes of both grey matter(cortex and striatum) and white matter(corpus callosum) to investigate the conversion efficiency, neuronal subtypes, and electrophysiological features of the converted neurons. We discover that NeuroD1 can efficiently reprogram the astrocytes in the grey matter into functional neurons, but the astrocytes in the white matter are much resistant to neuronal reprogramming. The converted neurons from cortical and striatal astrocytes are composed of both glutamatergic and GABAergic neurons, capable of firing action potentials and having spontaneous synaptic activities. In contrast, the few astrocyte-converted neurons in the white matter are rather immature with rare synaptic events. These results provide novel insights into the differential reprogramming capability between the astrocytes in the grey matter versus the white matter, and highlight the impact of regional astrocytes as well as microenvironment on the outcome of glia-toneuron conversion. Since human brain has large volume of white matter, this study will provide important guidance for future development of in vivo glia-to-neuron conversion technology into potential clinical therapies. Experimental protocols in this study were approved by the Laboratory Animal Ethics Committee of Jinan University(approval No. IACUC-20180321-03) on March 21, 2018.
基金supported by a grant from the Clinical Medicine Science and Technology Projects in Jiangsu Province of China,No.BL2014037a grant from the Changzhou City Science and Technology Support Plan in China,No.CE20165027+1 种基金a grant from the Changzhou Health Development Planning Commission Major Projects in China,No.ZD201515the Changzhou High-Level Health Personnel Training Project Funding
文摘With improvements in care of at-risk neonates, more and more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. Computed tomography, ultrasound, and conventional magnetic resonance imaging are helpful to diagnose brain injury, but cannot quantify white matter damage. In this study, ten full-term infants without brain injury and twenty-two full-term neonates with hypoxic-ischemic encephalopathy(14 moderate cases and 8 severe cases) underwent diffusion tensor imaging to assess its feasibility in evaluating white matter damage in this condition. Results demonstrated that fractional anisotropy, voxel volume, and number of fiber bundles were different in some brain areas between infants with brain injury and those without brain injury. The correlation between fractional anisotropy values and neonatal behavioral neurological assessment scores was closest in the posterior limbs of the internal capsule. We conclude that diffusion tensor imaging can quantify white matter injury in neonates with hypoxic-ischemic encephalopathy.
基金funded by the National Natural Science Foundation of China,No.81402904the Foundation of Shanghai Jiao Tong University School of Medicine,No.13XJ22001+1 种基金the Foundation of Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine,No.13YJ11a grant from the Science and Technology Commission of Shanghai Municipality of China,No.13ZR1426900,15411963900
文摘Carnosine is a dipeptide that scavenges free radicals,inhibits inflammation in the central nervous system,and protects against ischemic and hypoxic brain damage through its anti-oxidative and anti-apoptotic actions.Therefore,we hypothesized that carnosine would also protect against white matter damage caused by subcortical ischemic injury.White matter damage was induced by right unilateral common carotid artery occlusion in mice.The animals were treated with 200,500 or 750 mg/kg carnosine by intraperitoneal injection 30 minutes before injury and every other day after injury.Then,37 days later,Klüver-Barrera staining,toluidine blue staining and immunofluorescence staining were performed.Carnosine(200,500 mg/kg) substantially reduced damage to the white matter in the corpus callosum,internal capsule and optic tract,and it rescued expression of myelin basic protein,and alleviated the loss of oligodendrocytes.However,carnosine at the higher dose of 750 mg/kg did not have the same effects as the 200 and 500 mg/kg doses.These findings show that carnosine,at a particular dose range,protects against white matter damage caused by chronic cerebral ischemia in mice,likely by reducing oligodendroglial cell loss.
基金The Joint Fund between Natural Science Foundation of China and Shandong Province under contract No.U1606404the National Basic Research Program(973 Program)of China under contract Nos 2015CB452901 and 2015CB452902+1 种基金the National Key Research and Development Plan Sino-Australian Centre for Healthy Coasts under contract No.2016YFE0101500the Program for Aoshan Excellent Scholars of Qingdao National Laboratory for Marine Science and Technology of China under contract No.2015ASTP-OS13
文摘The Jiaozhou Bay is characterized by heavy eutrophication that is associated with intensive anthropogenic activities. Four core sediments from the Jiaozhou Bay are analyzed using bulk technologies, including sedimentary total organic carbon(TOC), total nitrogen(TN), the stable carbon(δ^(13)C) and nitrogen(δ^(15) N) isotopic composition to obtain the comprehensive understanding of the source and composition of sedimentary organic matter and further shed light on the environmental changes of the Jiaozhou Bay on a centennial time scale.Results suggest that the TOC and TN concentrations increase in the upper core, having indicated a probable eutrophication process since the 1920 s in the inner bay and the 2000 s in the bay mouth. The TOC and TN concentrations outside the bay have also changed since 1916 owing to the variation of terrigenous input.Considering TOC/TN ratio, δ^(13) C and δ^(15) N, it can be concluded there is a mixture of terrigenous and marine organic matter sources in the study area. A simple two end-member(terrigenous and marine) mixing model usingδ^(13) C indicats that 45%–79% of TOC in the Jiaozhou Bay is from the marine source. The environmental changes of the Jiaozhou Bay are recorded by geochemical proxies, which are influenced by the intensive anthropogenic activities(e.g., extensive use of fertilizers, and discharge of sewage) and climate changes(e.g., rainfall).
基金This work was supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT,Ministry of Science and ICT)(NRF-2018M3A9E8023853(to JYC)NRF-2018R1C1B6006145(to JYC)NRF-2018R1A2A1A05020292(to BGK)and NRF-2019R1A5A2026045(to JYC and BGK).
文摘Subcortical ischemic white matter injury(SIWMI),pathological correlate of white matter hyperintensities or leukoaraiosis on magnetic resonance imaging,is a common cause of cognitive decline in elderly.Despite its high prevalence,it remains unknown how various components of the white matter degenerate in response to chronic ischemia.This incomplete knowledge is in part due to a lack of adequate animal model.The current review introduces various SIWMI animal models and aims to scrutinize their advantages and disadvantages primarily in regard to the pathological manifestations of white matter components.The SIWMI animal models are categorized into 1)chemically induced SIWMI models,2)vascular occlusive SIWMI models,and 3)SIWMI models with comorbid vascular risk factors.Chemically induced models display consistent lesions in predetermined areas of the white matter,but the abrupt evolution of lesions does not appropriately reflect the progressive pathological processes in human white matter hyperintensities.Vascular occlusive SIWMI models often do not exhibit white matter lesions that are sufficiently unequivocal to be quantified.When combined with comorbid vascular risk factors(specifically hypertension),however,they can produce progressive and definitive white matter lesions including diffuse rarefaction,demyelination,loss of oligodendrocytes,and glial activation,which are by far the closest to those found in human white matter hyperintensities lesions.However,considerable surgical mortality and unpredictable natural deaths during a follow-up period would necessitate further refinements in these models.In the meantime,in vitro SIWMI models that recapitulate myelinated white matter track may be utilized to study molecular mechanisms of the ischemic white matter injury.Appropriate in vivo and in vitro SIWMI models will contribute in a complementary manner to making a breakthrough in developing effective treatment to prevent progression of white matter hyperintensities.
基金supported by JSPS KAKENHI(No.JP 15K20002)Yamaguchi University School of Medicine Affiliated Hospital:Translational Promotion Grant and President of Yamaguchi University Strategic Expenses:Young Researcher Support Project(all to NN)
文摘The spinal cord is composed of gray matter and white matter.It is well known that the properties of these two tissues differ considerably.Spinal diseases often present with symptoms that are caused by spinal cord compression.Understanding the mechanical properties of gray and white matter would allow us to gain a deep understanding of the injuries caused to the spinal cord and provide information on the pathological changes to these distinct tissues in several disorders.Previous studies have reported on the physical properties of gray and white matter,however,these were focused on longitudinal tension tests.Little is known about the differences between gray and white matter in terms of their response to compression.We therefore performed mechanical compression test of the gray and white matter of spinal cords harvested from cows and analyzed the differences between them in response to compression.We conducted compression testing of gray matter and white matter to detect possible differences in the collapse rate.We found that increased compression(especially more than 50%compression)resulted in more severe injuries to both the gray and white matter.The present results on the mechanical differences between gray and white matter in response to compression will be useful when interpreting findings from medical imaging in patients with spinal conditions.
基金supported by the Project of Science and Technology Department of Jilin Province in China,No.20160101023JC
文摘We observed the characteristics of white matter fibers and gray matter in multiple sclerosis patients, to identify changes in diffusion tensor imaging fractional anisotropy values following white matter fiber injury. We analyzed the correlation between fractional anisotropy values and changes in whole-brain gray matter volume. The participants included 20 patients with relapsing-remitting multiple sclerosis and 20 healthy volunteers as controls. All subjects underwent head magnetic resonance imaging and diffusion tensor imaging. Our results revealed that fractional anisotropy values decreased and gray matter volumes were reduced in the genu and splenium of corpus callosum, left anterior thalamic radiation, hippocampus, uncinate fasciculus, right corticospinal tract, bilateral cingulate gyri, and inferior longitudinal fasciculus in multiple sclerosis patients. Gray matter volumes were significantly different between the two groups in the right frontal lobe(superior frontal, middle frontal, precentral, and orbital gyri), right parietal lobe(postcentral and inferior parietal gyri), right temporal lobe(caudate nucleus), right occipital lobe(middle occipital gyrus), right insula, right parahippocampal gyrus, and left cingulate gyrus. The voxel sizes of atrophic gray matter positively correlated with fractional anisotropy values in white matter association fibers in the patient group. These findings suggest that white matter fiber bundles are extensively injured in multiple sclerosis patients. The main areas of gray matter atrophy in multiple sclerosis are the frontal lobe, parietal lobe, caudate nucleus, parahippocampal gyrus, and cingulate gyrus. Gray matter atrophy is strongly associated with white matter injury in multiple sclerosis patients, particularly with injury to association fibers.
基金supported by grants from the National Key R&D Program of China,No.2017YFA0104704(to BQL)the Young Elite Scientist Sponsorship Program(YESS)by China Association for Science and Technology(CAST),No.2018QNRC001(to BQL)+1 种基金the Fundamental Research Funds for the Central Universities,China,No.18ykpy38(to BQL)the National Natural Science Foundation of China,Nos.81971157(to BQL),81891003(to YSZ).
文摘Axon regeneration and remyelination of the damaged region is the most common repair strategy for spinal cord injury.However,achieving good outcome remains difficult.Our previous study showed that porcine decellularized optic nerve better mimics the extracellular matrix of the embryonic porcine optic nerve and promotes the directional growth of dorsal root ganglion neurites.However,it has not been reported whether this material promotes axonal regeneration in vivo.In the present study,a porcine decellularized optic nerve was seeded with neurotrophin-3-overexpressing Schwann cells.This functional scaffold promoted the directional growth and remyelination of regenerating axons.In vitro,the porcine decellularized optic nerve contained many straight,longitudinal channels with a uniform distribution,and microscopic pores were present in the channel wall.The spatial micro topological structure and extracellular matrix were conducive to the adhesion,survival and migration of neural stem cells.The scaffold promoted the directional growth of dorsal root ganglion neurites,and showed strong potential for myelin regeneration.Furthermore,we transplanted the porcine decellularized optic nerve containing neurotrophin-3-overexpressing Schwann cells in a rat model of T10 spinal cord defect in vivo.Four weeks later,the regenerating axons grew straight,the myelin sheath in the injured/transplanted area recovered its structure,and simultaneously,the number of inflammatory cells and the expression of chondroitin sulfate proteoglycans were reduced.Together,these findings suggest that porcine decellularized optic nerve loaded with Schwann cells overexpressing neurotrophin-3 promotes the directional growth of regenerating spinal cord axons as well as myelin regeneration.All procedures involving animals were conducted in accordance with the ethical standards of the Institutional Animal Care and Use Committee of Sun Yat-sen University(approval No.SYSU-IACUC-2019-B034)on February 28,2019.
基金Supported by National Natural Science Foundation of China(41361068)Key Science and Technology Research Funds for Guangxi Universities(2013ZD067)Guangxi Natural Science Foundation(2011GXNSFB-018056)
文摘Rational fertilization is an important measure to increase crop yield and soil fertility. Through analysis,this paper aims to master the change characteristics of soil organic matter and rice yield under different fertilizer treatments,in order to provide an important reference for the sustainable use of soil and effective fertilization. Long-term( 19 years) rice crop rotation experiments in waterloggogenic paddy soil were conducted to investigate the change trend of crop grain yield and soil organic matter with time,reveal the dynamic characteristics and relationship between main fertility factors and crop yields using comparative analysis at three sites with conventional fertilization and non-fertilization in Guilin. The results showed that compared with previous years,the rice yield increased by 53% under the fertilization treatment and degreased by 66% under the control. Over the years,the average soil organic matter( SOM) content under fertilization treatment was 23% higher than under CK treatment. This indicates that chemical fertilizer and organic manure application can increase the rice yield and soil organic matter,and high rice yield can be attributed to the SOM increase.
文摘Efficient strategies for neuroprotection and repair are still an unmet medical need for neurodegenerative diseases and lesions of the central nervous system.Over the last few decades,a great deal of attention has been focused on white matter as a potential therapeutic target,mainly due to the discovery of the oligodendrocyte precursor cells in the adult central nervous system,a cell type able to fully repair myelin damage,and to the development of advanced imaging techniques to visualize and measure white matter lesions.The combination of these two events has greatly increased the body of research into white matter alte rations in central nervous system lesions and neurodegenerative diseases and has identified the oligodendrocyte precursor cell as a putative target for white matter lesion repair,thus indirectly contributing to neuroprotection.This review aims to discuss the potential of white matter as a therapeutic target for neuroprotection in lesions and diseases of the central nervous system.Pivot conditions are discussed,specifically multiple scle rosis as a white matter disease;spinal cord injury,the acute lesion of a central nervous system component where white matter prevails over the gray matte r,and Alzheimer's disease,where the white matter was considered an ancilla ry component until recently.We first describe oligodendrocyte precursor cell biology and developmental myelination,and its regulation by thyroid hormones,then briefly describe white matter imaging techniques,which are providing information on white matter involvement in central nervous system lesions and degenerative diseases.Finally,we discuss pathological mechanisms which interfere with myelin repair in adulthood.
