Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial ac...Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.展开更多
BACKGROUNDNon-alcoholic fatty liver disease (NAFLD) is a systemic disease with bidirectionalrelationships with cardiovascular disease (CVD). Non-alcoholic steatohepatitis(NASH) is a more severe subtype of NAFLD. Patie...BACKGROUNDNon-alcoholic fatty liver disease (NAFLD) is a systemic disease with bidirectionalrelationships with cardiovascular disease (CVD). Non-alcoholic steatohepatitis(NASH) is a more severe subtype of NAFLD. Patients with NASH exhibit moreintra and extrahepatic inflammation, procoagulant imbalances andproatherogenic lipid profiles. Whether NASH increases the risk of ischemic heartdisease is currently unclear.AIMTo investigate the relationship between acute myocardial infarction (MI) andNASH in a large cohort of subjects in the United States.METHODSWe reviewed data from a large commercial database (Explorys IBM) thataggregates electronic health records from 26 large nationwide healthcare systems.Using systemized nomenclature of clinical medical terms (SNOMED CT), weidentified adult with the diagnosis of NASH from 1999-2019. We includedpatients with the diagnosis of acute MI from 2018-2019. Comorbidities known tobe associated with NASH and MI such as obesity, diabetes mellitus,hyperlipidemia, smoking, male gender, and hypertension were collected.Univariable and multivariable analyses were performed to investigate whetherNASH is independently associated with the risk of MI.RESULTSOut of 55099280 patients, 43170 were diagnosed with NASH (0.08%) and 107000(0.194%) had a MI within 2018-2019. After adjusting for traditional risk factors,NASH conferred greater odds of MI odds ratio (OR) 1.5 [95% confidence interval(CI): 1.40-1.62]. Hyperlipidemia had the strongest association with MI OR 8.39(95%CI: 8.21-8.58) followed by hypertension OR 3.11 (95%CI: 3.05-3.17) andsmoking OR 2.83 (95%CI: 2.79-2.87). NASH had a similar association with MI asthe following traditional risk factors like age above 65 years OR 1.47 (95%CI: 1.45-1.49), male gender OR 1.53 (95%CI: 1.51-1.55) diabetes mellitus OR 1.89 (95%CI:1.86-1.91).CONCLUSIONMI appears to be a prevalent disease in NASH. Patients with NASH may needearly identification and aggressive cardiovascular risk modification.展开更多
Effect sizes are estimated from several study designs when the subjects are individually sampled. When the samples are the aggregate cluster of individuals, the within cluster correlation must be accounted for to cons...Effect sizes are estimated from several study designs when the subjects are individually sampled. When the samples are the aggregate cluster of individuals, the within cluster correlation must be accounted for to construct correct confidence intervals, and to conduct valid statistical inference. The purpose of this article is to propose and evaluate statistical procedures for the estimation of the variance of the estimated attributable risk in parallel groups of clusters, and in a design dividing each of k clusters into two segments creating multiple sub-clusters. The estimated variance is the first order approximation and is obtained by the delta method. We apply the methodology and propose a Wald type confidence interval on the difference between two correlated attributable risks. We also construct a test on the hypothesis of equality of two correlated attributable risks. We evaluate the power of the proposed test via Monte-Carlo simulations.展开更多
Background: Repeatability is a statement on the magnitude of measurement error. When biomarkers are used for disease diagnoses, they should be measured accurately. Objectives: We derive an index of repeatability based...Background: Repeatability is a statement on the magnitude of measurement error. When biomarkers are used for disease diagnoses, they should be measured accurately. Objectives: We derive an index of repeatability based on the ratio of two variance components. Estimation of the index is derived from the one-way Analysis of Variance table based on the one-way random effects model. We estimate the large sample variance of the estimator and assess its adequacy using bootstrap methods. An important requirement for valid estimation of repeatability is the availability of multiple observations on each subject taken by the same rater and under the same conditions. Methods: We use the delta method to derive the large sample variance of the estimate of repeatability index. The question related to the number of required repeats per subjects is answered by two methods. In first methods we estimate the number of repeats that minimizes the variance of the estimated repeatability index, and the second determine the number of repeats needed under cost-constraints. Results and Novel Contribution: The situation when the measurements do not follow Gaussian distribution will be dealt with. It is shown that the required sample size is quite sensitive to the relative cost. We illustrate the methodologies on the Serum Alanine-aminotransferase (ALT) available from hospital registry data for samples of males and females. Repeatability is higher among females in comparison to males.展开更多
<strong>Objective</strong><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>Since the...<strong>Objective</strong><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>Since the identification of COVID-19 in December 2019 as a pandemic, over 4500 research papers were published with the term “COVID-19” contained in its title. Many of these reports on the COVID-19 pandemic suggested that the coronavirus was associated with more serious chronic diseases and mortality particularly in patients with chronic diseases regardless of country and age. Therefore, there is a need to understand how common comorbidities and other factors are associated with the risk of death due to COVID-19 infection. Our investigation aims at exploring this relationship. Specifically, our analysis aimed to explore the relationship between the total number of COVID-19 cases and mortality associated with COVID-19 infection accounting for other risk factors. </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: Due to the presence of over dispersion, the Negative Binomial Regression is used to model the aggregate number of COVID-19 cases. Case-fatality associated with this infection is modeled as an outcome variable using machine learning predictive multivariable regression. The data we used are the COVID-19 cases and associated deaths from the start of the pandemic up to December 02-2020, the day Pfizer was granted approval for their new COVID-19 vaccine. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: Our analysis found significant regional variation in case fatality. Moreover, the aggregate number of cases had several risk factors including chronic kidney disease, population density and the percentage of gross domestic product spent on healthcare. </span><b><span style="font-family:Verdana;">The Conclusions</span></b><span style="font-family:Verdana;">: There are important regional variations in COVID-19 case fatality. We identified three factors to be significantly correlated with case fatality</span></span></span></span><span style="font-family:Verdana;">.</span>展开更多
The horticultural sector has undergone tremendous growth in Kenya and is now the second largest foreign income earning sector in the country. Lake Naivasha is the hub of large scale horticultural farming in Kenya. Thi...The horticultural sector has undergone tremendous growth in Kenya and is now the second largest foreign income earning sector in the country. Lake Naivasha is the hub of large scale horticultural farming in Kenya. This growth coupled with increased use of pesticides, may increase the possibility of pesticide exposure and its associated risks to workers and residents of the region. The purpose of this study was to assess the symptoms commonly experienced by residents of Naivasha town and their possible association to pesticide exposure. Purposive sampling of residents from Kamere, Kwa Muia, Kioto and Karagita was performed, as these residential areas have significant numbers of flower farm workers. By random selection, a total of 801 community members were recruited to participate in the study and data was collected by completing the prepared questionnaire and from clinical examinations. Results indicate that several residents exhibited respiratory;skin, joints and bones;and nervous system symptoms. We found a higher frequency of symptoms among planters, weeders, harvesters than in sprayers working in horticultural farms. We recommend training to planters, weeders, harvesters who are mainly women (61.6%) in this study concerning pesticide use as do sprayers;and second, longer reentry times between the last spraying of pesticide and entry of these workers is warranted, particularly in greenhouses. In this regard, reentry times for greenhouses and fields established for specific pesticides in Europe, North America, Japan or Australia should be adapted by Kenya, and these guidelines enforced by the Government of Kenya to reduce exposure to pesticides within this vulnerable work group. These workers should also use protective clothing including gloves and masks at all times while handling chemicals or recently sprayed plants or flowers. It would also be prudent for flower farm owners to introduce an integrated pest management regime to reduce pesticide use andworker exposures. Further research is required both to identify validated biomarkers that can reliably be used to identify pesticide exposure prior to the occurrence of acute toxicity;and to follow up individual cases of known exposures for chronic health effects.展开更多
<span style="font-family:""><span style="font-family:Verdana;">Infection with </span><i><span style="font-family:Verdana;">Toxoplasma gondii</span>...<span style="font-family:""><span style="font-family:Verdana;">Infection with </span><i><span style="font-family:Verdana;">Toxoplasma gondii</span></i><span style="font-family:Verdana;">, is one of the most widespread zoonoses in the world. Congenital Toxoplasmosis (CT) is particularly risky due to its fetal </span><span style="font-family:Verdana;">complications. Sulfadiazine (SDZ) and Pyrimethamine (PYR) are usually </span><span style="font-family:Verdana;">used </span><span style="font-family:Verdana;">for CT treatment in Argentina, to prevent morbidity. Due to the lack of </span><span style="font-family:Verdana;">commercial pediatric formulations, these must be prepared in the hospital pharmacy. This is the first report of serum concentrations measures in pediatric CT therapy for this combination of drugs. A bioanalytical method was developed for identification and simultaneous quantification of SDZ and PYR by High Performance Liquid Chromatography (HPLC) with UV detection. The validated method was applied to residual serum samples obtained from 6 pediatric patients undergoing treatment with SDZ 42.20 a 93.70 mg/kg/day and </span><span style="font-family:Verdana;">PYR 0.77 a 2.70 mg/kg/day. Sample pretreatment consisted </span></span><span style="font-family:Verdana;">on</span><span style="font-family:Verdana;"> a</span><span style="font-family:""><span style="font-family:Verdana;"> deproteini</span><span style="font-family:Verdana;">zation step followed by centrifugation and then injection of supernatant.</span><span style="font-family:Verdana;"> Limit of Detection (LOD) and Quantification (LOQ) were (0.17 ± 0.02 and 0.13 ± 0.02) μg/mL and (0.46 ± 0.01 and 0.36 ± 0.01) μg/mL for SDZ and PYR respectively, with an appropriate linear range. Concentrations range found </span><span style="font-family:Verdana;">were (<LOD</span></span><span style="font-family:Verdana;"> - </span><span style="font-family:Verdana;">162.04 ± 0.02) μg/mL for SDZ and (<LOD</span><span style="font-family:Verdana;"> - </span><span style="font-family:Verdana;">7.30 ± 0.03) </span><span style="font-family:""><span style="font-family:Verdana;">μg/mL for PYR. We developed and validated in real pediatric samples, an acute, pre</span><span style="font-family:Verdana;">cise and low-cost method for quantification of SDZ and PYR using a </span><span style="font-family:Verdana;">non-so</span><span style="font-family:Verdana;">phisticate chromatographic equipment, suitable for hospital therapeutic </span><span style="font-family:Verdana;">monitoring for public health system.展开更多
Objectives: We introduce a special form of the Generalized Poisson Distribution. The distribution has one parameter, yet it has a variance that is larger than the mean a phenomenon known as “over dispersion”. We dis...Objectives: We introduce a special form of the Generalized Poisson Distribution. The distribution has one parameter, yet it has a variance that is larger than the mean a phenomenon known as “over dispersion”. We discuss potential applications of the distribution as a model of counts, and under the assumption of independence we will perform statistical inference on the ratio of two means, with generalization to testing the homogeneity of several means. Methods: Bayesian methods depend on the choice of the prior distributions of the population parameters. In this paper, we describe a Bayesian approach for estimation and inference on the parameters of several independent Inflated Poisson (IPD) distributions with two possible priors, the first is the reciprocal of the square root of the Poisson parameter and the other is a conjugate Gamma prior. The parameters of Gamma distribution are estimated in the empirical Bayesian framework using the maximum likelihood (ML) solution using nonlinear mixed model (NLMIXED) in SAS. With these priors we construct the highest posterior confidence intervals on the ratio of two IPD parameters and test the homogeneity of several populations. Results: We encountered convergence problem in estimating the hyperparameters of the posterior distribution using the NLMIXED. However, direct maximization of the predictive density produced solutions to the maximum likelihood equations. We apply the methodologies to RNA-SEQ read count data of gene expression values.展开更多
Objective: We aim to detect over-time variations in mortality of liver transplant recipients stratified by the period of transplant. Since this is a retrospective investigation, bias reduction caused by possible confo...Objective: We aim to detect over-time variations in mortality of liver transplant recipients stratified by the period of transplant. Since this is a retrospective investigation, bias reduction caused by possible confounding effects can be achieved by using propensity score weighting in a multivariate logistic regression model. Methods: Medical charts of all adult liver transplant recipients (n = 250) who were transplanted in three periods 2005-2009, 2010-2014 and 2015-2019 were retrospectively reviewed. The following recipient factors were analyzed: recipients and donors’ ages, sex, renal impairment, body mass index (BMI), presence of bacterial or viral infections, MELD (Model for end-stage diseases). Multivariate logistic model adjusted by Propensity Scores (PS) was used to identify the effect of the risk factors on mortality, and death within five years, in the targeted time frame. Patient outcomes are recorded as;(patient status = 1 if dead, or patient status = 0 if alive). Results: Meld score, recipient age, and renal impairments were shown to be predictors of mortality in transplanted patients. Multivariate regression model was used to identify the significance of the specified risk factors, followed by pairwise comparisons between periods. Pairwise comparisons between periods using logistic regression weighted by the inverse propensity score, correcting for the possible confounding effect of measured covariates showed that the death rate is significantly reduced in subsequent periods as compared to the initial period. Conclusions: The clinical implications of these findings are the ability to stratify patients at high risk of posttransplant death by planning more intensive and accurate management for them.展开更多
Background: When continuous scale measurements are available, agreements between two measuring devices are assessed both graphically and analytically. In clinical investigations, Bland and Altman proposed plotting sub...Background: When continuous scale measurements are available, agreements between two measuring devices are assessed both graphically and analytically. In clinical investigations, Bland and Altman proposed plotting subject-wise differences between raters against subject-wise averages. In order to scientifically assess agreement, Bartko recommended combining the graphical approach with the statistical analytic procedure suggested by Bradley and Blackwood. The advantage of using this approach is that it enables significance testing and sample size estimation. We noted that the direct use of the results of the regression is misleading and we provide a correction in this regard. Methods: Graphical and linear models are used to assess agreements for continuous scale measurements. We demonstrate that software linear regression results should not be readily used and we provided correct analytic procedures. The degrees of freedom of the F-statistics are incorrectly reported, and we propose methods to overcome this problem by introducing the correct analytic form of the F statistic. Methods for sample size estimation using R-functions are also given. Results: We believe that the tutorial and the R-codes are useful tools for testing and estimating agreement between two rating protocols for continuous scale measurements. The interested reader may use the codes and apply them to their available data when the issue of agreement between two raters is the subject of interest.展开更多
Restless legs syndrome(RLS)is a common sleep-related movement disorder characterised by an uncomfortable urge to move the legs that occurs during periods of inactivity.Although there have been many case reports on ant...Restless legs syndrome(RLS)is a common sleep-related movement disorder characterised by an uncomfortable urge to move the legs that occurs during periods of inactivity.Although there have been many case reports on antipsychotic-induced RLS,ziprasidone has never been reported as a cause of RLS.We present a case of a female patient with schizophrenia who presented with symptoms of RLS following the administration of high doses of ziprasidone added to quetiapine and valproate.The patient’s symptoms of RLS occurred following the administration and titration of ziprasidone to 160 mg,and were relieved upon reducing the dose to 120 mg/day.Other potential causative medications and differential diagnoses that could have caused similar symptoms were excluded.Clinicians should be aware of the potential for ziprasidone-induced RLS.Dopamine and serotonin interaction could be the mechanism underlying ziprasidone-induced RLS.展开更多
The therapeutic properties of Lactobacillus rhamnosus GR-1 and ginseng extracts have been well documented. The objective of this study was to measure growth and survival of L. rhamnosus GR-1 in milk fortified with gin...The therapeutic properties of Lactobacillus rhamnosus GR-1 and ginseng extracts have been well documented. The objective of this study was to measure growth and survival of L. rhamnosus GR-1 in milk fortified with ginseng extracts during storage period of 28 days. Five formulations of milk (1% fat) were prepared. Two samples were fortified with alcoholic ginseng extract (AGE: 150 μg/mL, AGE: 500 μg/mL) and the other two samples were fortified with aqueous ginseng extract (QGE: 150 μg/mL, QGE: 500 μg/ml) and one with no ginseng extract (C). The mixtures were autoclaved for 15 min, cooled to 37?C and inoculated with 1% starter culture. The samples were then incubated anaerobically at 37℃ overnight. Selective MRS agar containing 0.015 g/L fusidic acid was used to enumerate L. rhamnosus GR-1 after 1, 14, and 28 d storage at 4℃. All ginseng-fortified samples supported the growth and survival of L. rhamnosus GR-1, as viable counts were detected at each measurement point throughout the 28 d storage period. After 1 d of storage, total colony counts for L. rhamnosus GR-1 in AGE: 150 μg/mL and AGE: 500 μg/mL were 1.3 × 109 and 1.4 × 109 CFU/mL, respectively;probiotic counts in QGE 150 μg/mL and QGE: 500 μg/mL were 1.5 × 109 and 1.4 × 109 CFU/mL, respectively. Additionally, L. rhamnosus GR-1 viability remained stable throughout the 28 days storage period, as no significant decrease (p L. rhamnosus GR-1 can remain viable in presence of ginseng extracts during storage period and there is potential for incorporating ginseng extracts in other probiotic dairy products.展开更多
Dear editor,Dr.Peter Drummond’s article noted that peripheral nerve and tissue injury in neuropathic pain syndromes releases cytokines which in turn lead to an increase in alpha1-adrenoceptor upregulation,resulting i...Dear editor,Dr.Peter Drummond’s article noted that peripheral nerve and tissue injury in neuropathic pain syndromes releases cytokines which in turn lead to an increase in alpha1-adrenoceptor upregulation,resulting in a heightened sensitivity to noradrenaline.In these circumstances,noradrenaline acting on upregulated alpha1a-adrenoceptors increases the release of cytokine interleukin-6.Hence,nociceptive afferent neurons exposed to injury induced cytokines become more hypersensitive to noradrenaline。展开更多
Background: Factors associated with hospital mortality are usually identified and their effects are quantified through statistical modeling. To guide the choice of the best statistical model, we first quantify the pre...Background: Factors associated with hospital mortality are usually identified and their effects are quantified through statistical modeling. To guide the choice of the best statistical model, we first quantify the predictive ability of each model and then use the CIHI index to see if the hospital policy needs any change. Objectives: The main purpose of this study compared three statistical models in the evaluation of the association between hospital mortality and two risk factors, namely subject’s age at admission and the length of stay, adjusting for the effect of Diagnostic Related Groups (DRG). Methods: We use several SAS procedures to quantify the effect of DRG on the variability in hospital mortality. These procedures are the Logistic Regression model (ignoring the DRG effect), the Generalized Estimating Equation (GEE) that takes into account the within DRG clustering effect (but the within cluster correlation is treated as nuisance parameter), and the Generalized Linear Mixed Model (GLIMMIX). We showed that the GLIMMIX is superior to other models as it properly accounts for the clustering effect of “Diagnostic Related Groups” denoted by DRG. Results: The GLM procedure showed that the proportional contribution of DRG is 16%. All three models showed significant and increasing trend in mortality (P < 0.0001) with respect to the two risk factors (age at admission, and hospital length of stay). It was also clear that the CIHI index was not different under the three models. We re-estimated the models parameters after dichotomizing the risk factors at the optimal cut-off points, using the ROC curve. The parameters estimates and their significance did not change.展开更多
<strong>Background: </strong><span style="font-family:""><span style="font-family:Verdana;">One of the main objectives of hospital managements is to control the length ...<strong>Background: </strong><span style="font-family:""><span style="font-family:Verdana;">One of the main objectives of hospital managements is to control the length of stay (LOS). Successful control of LOS of inpatients will result in reduction in the cost of care, decrease in nosocomial infections, medication side effects, and better management of the limited number of available patients’ beds. The length of stay (LOS) is an important indicator of the efficiency of hospital management by improving the quality of treatment, and increased hospital profit with more efficient bed management. The purpose of this study was to model the distribution of LOS as a function of patient’s age, and the Diagnosis Related Groups (DRG), based on electronic medical records of a large tertiary care hospital. </span><b><span style="font-family:Verdana;">Materials and Methods: </span></b><span style="font-family:Verdana;">Information related to the research subjects were retrieved from a database of patients admitted to King Faisal Specialist Hospital and Research Center hospital in Riyadh, Saudi Arabia between January 2014 and December 2016. Subjects’ confidential information was masked from the investigators. The data analyses were reported visually, descriptively, and analytically using Cox proportional hazard regression model to predict the risk of long-stay when patients’ age and the DRG are considered as antecedent risk factors. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">Predicting the risk of long stay depends significantly on the age at admission, and the DRG to which a patient belongs to. We demonstrated the validity of the Cox regression model for the available data as the proportionality assumption is shown to be satisfied. Two examples were presented to demonstrate the utility of the Cox model in this regard.</span></span>展开更多
Count data that exhibit over dispersion (variance of counts is larger than its mean) are commonly analyzed using discrete distributions such as negative binomial, Poisson inverse Gaussian and other models. The Poisson...Count data that exhibit over dispersion (variance of counts is larger than its mean) are commonly analyzed using discrete distributions such as negative binomial, Poisson inverse Gaussian and other models. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial and the Poisson inverse Gaussian have variance larger than the mean and therefore are more appropriate to model over-dispersed count data. As an alternative to these two models, we shall use the generalized Poisson distribution for group comparisons in the presence of multiple covariates. This problem is known as the ANCOVA and is solved for continuous data. Our objectives were to develop ANCOVA using the generalized Poisson distribution, and compare its goodness of fit to that of the nonparametric Generalized Additive Models. We used real life data to show that the model performs quite satisfactorily when compared to the nonparametric Generalized Additive Models.展开更多
Background: The Poisson and the Negative Binomial distributions are commonly used to model count data. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial has a variance lar...Background: The Poisson and the Negative Binomial distributions are commonly used to model count data. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial has a variance larger than the mean and therefore both models are appropriate to model over-dispersed count data. Objectives: A new two-parameter probability distribution called the Quasi-Negative Binomial Distribution (QNBD) is being studied in this paper, generalizing the well-known negative binomial distribution. This model turns out to be quite flexible for analyzing count data. Our main objectives are to estimate the parameters of the proposed distribution and to discuss its applicability to genetics data. As an application, we demonstrate that the QNBD regression representation is utilized to model genomics data sets. Results: The new distribution is shown to provide a good fit with respect to the “Akaike Information Criterion”, AIC, considered a measure of model goodness of fit. The proposed distribution may serve as a viable alternative to other distributions available in the literature for modeling count data exhibiting overdispersion, arising in various fields of scientific investigation such as genomics and biomedicine.展开更多
Objectives: Developing inference procedures on the quasi-binomial distribution and the regression model. Methods: Score testing and the method of maximum likelihood for regression parameters estimation. Data: Several ...Objectives: Developing inference procedures on the quasi-binomial distribution and the regression model. Methods: Score testing and the method of maximum likelihood for regression parameters estimation. Data: Several examples are included, based on published data. Results: A quasi-binomial model is used to model binary response data which exhibit extra-binomial variation. A partial score test on the binomial hypothesis versus the quasi-binomial alternative is developed and illustrated on three data sets. The extended logit transformation on the binomial parameter is introduced and the large sample dispersion matrix of the estimated parameters is derived. The Nonlinear Mixed Procedure (NLMIXED) in SAS is shown to be very appropriate for the estimation of nonlinear regression.展开更多
Background: Cardiovascular diseases (CVDs) are the leading cause of death globally. An estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Of these deaths, 85% were due to hear...Background: Cardiovascular diseases (CVDs) are the leading cause of death globally. An estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Of these deaths, 85% were due to heart attack and stroke. Over three quarters of CVD deaths take place in low- and middle-income countries. We have studied the pattern of mortality due to cardiovascular in the six countries of the Arabian Gulf and its association with obesity over the 29 years 1990 to 2019. Methods: We used the linear mixed effect models to investigate the pattern of CVD mortality over the year 1990 to 2019, together with the pattern of change in one of the most important risk factors that is obesity, and its association with CVD mortality over the same period. Conclusions: Although there were fluctuations in the pattern of mortality and the prevalence of obesity over the specified period, there has been a steady decline in the per-100,000 number of deaths and the prevalence of obesity. However, there was a strong association between the two variables. From the fitted models we estimated that a one percent increase in obesity is associated with an average increase in cardiovascular deaths of 2.7 deaths per 100,000.展开更多
Objective:The holmium:yttrium-aluminium-garnet laser(Ho:YAG)has been the gold standard for laser lithotripsy over the last three decades.After demonstrating good in vitro efficacy,the thulium fiber laser(TFL)has been ...Objective:The holmium:yttrium-aluminium-garnet laser(Ho:YAG)has been the gold standard for laser lithotripsy over the last three decades.After demonstrating good in vitro efficacy,the thulium fiber laser(TFL)has been recently released in the market and the initial clinical results are encouraging.This article aims to review the main technology differences between the Ho:YAG laser and the TFL,discuss the initial clinical results with the TFL as well as the optimal settings for TFL lithotripsy.Methods:We reviewed the literature focusing on the technological aspects of the Ho:YAG laser and TFL as well as the results of in vitro and in vivo studies comparing both technologies.Results:In vitro studies show a technical superiority of TFL compared to the Ho:YAG laser and encouraging results have been demonstrated in clinical practice.However,as TFL is a new technology,limited studies are currently available,and the optimal settings for lithotripsy are not yet established.Conclusion:TFL has the potential to be an alternative to the Ho:YAG laser,but more reports are still needed to determine the optimal laser for lithotripsy of urinary tract stones when considering all parameters including effectiveness,safety,and costs.展开更多
基金supported by Canadian Institutes for Health Research (CIHR)(to ADR and WW)Ontario Graduate Scholarship (to NOB)+2 种基金Alzheimer's Society of CanadaHeart and Stroke Foundation of Canada,CIHRthe Canadian Consortium for Neurodegeneration and Aging (CCNA)(to SNW)。
文摘Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.
基金We gratefully acknowledge Dr.Joseph Sudano for ensuring the data analysis is appropriate for this research.
文摘BACKGROUNDNon-alcoholic fatty liver disease (NAFLD) is a systemic disease with bidirectionalrelationships with cardiovascular disease (CVD). Non-alcoholic steatohepatitis(NASH) is a more severe subtype of NAFLD. Patients with NASH exhibit moreintra and extrahepatic inflammation, procoagulant imbalances andproatherogenic lipid profiles. Whether NASH increases the risk of ischemic heartdisease is currently unclear.AIMTo investigate the relationship between acute myocardial infarction (MI) andNASH in a large cohort of subjects in the United States.METHODSWe reviewed data from a large commercial database (Explorys IBM) thataggregates electronic health records from 26 large nationwide healthcare systems.Using systemized nomenclature of clinical medical terms (SNOMED CT), weidentified adult with the diagnosis of NASH from 1999-2019. We includedpatients with the diagnosis of acute MI from 2018-2019. Comorbidities known tobe associated with NASH and MI such as obesity, diabetes mellitus,hyperlipidemia, smoking, male gender, and hypertension were collected.Univariable and multivariable analyses were performed to investigate whetherNASH is independently associated with the risk of MI.RESULTSOut of 55099280 patients, 43170 were diagnosed with NASH (0.08%) and 107000(0.194%) had a MI within 2018-2019. After adjusting for traditional risk factors,NASH conferred greater odds of MI odds ratio (OR) 1.5 [95% confidence interval(CI): 1.40-1.62]. Hyperlipidemia had the strongest association with MI OR 8.39(95%CI: 8.21-8.58) followed by hypertension OR 3.11 (95%CI: 3.05-3.17) andsmoking OR 2.83 (95%CI: 2.79-2.87). NASH had a similar association with MI asthe following traditional risk factors like age above 65 years OR 1.47 (95%CI: 1.45-1.49), male gender OR 1.53 (95%CI: 1.51-1.55) diabetes mellitus OR 1.89 (95%CI:1.86-1.91).CONCLUSIONMI appears to be a prevalent disease in NASH. Patients with NASH may needearly identification and aggressive cardiovascular risk modification.
文摘Effect sizes are estimated from several study designs when the subjects are individually sampled. When the samples are the aggregate cluster of individuals, the within cluster correlation must be accounted for to construct correct confidence intervals, and to conduct valid statistical inference. The purpose of this article is to propose and evaluate statistical procedures for the estimation of the variance of the estimated attributable risk in parallel groups of clusters, and in a design dividing each of k clusters into two segments creating multiple sub-clusters. The estimated variance is the first order approximation and is obtained by the delta method. We apply the methodology and propose a Wald type confidence interval on the difference between two correlated attributable risks. We also construct a test on the hypothesis of equality of two correlated attributable risks. We evaluate the power of the proposed test via Monte-Carlo simulations.
文摘Background: Repeatability is a statement on the magnitude of measurement error. When biomarkers are used for disease diagnoses, they should be measured accurately. Objectives: We derive an index of repeatability based on the ratio of two variance components. Estimation of the index is derived from the one-way Analysis of Variance table based on the one-way random effects model. We estimate the large sample variance of the estimator and assess its adequacy using bootstrap methods. An important requirement for valid estimation of repeatability is the availability of multiple observations on each subject taken by the same rater and under the same conditions. Methods: We use the delta method to derive the large sample variance of the estimate of repeatability index. The question related to the number of required repeats per subjects is answered by two methods. In first methods we estimate the number of repeats that minimizes the variance of the estimated repeatability index, and the second determine the number of repeats needed under cost-constraints. Results and Novel Contribution: The situation when the measurements do not follow Gaussian distribution will be dealt with. It is shown that the required sample size is quite sensitive to the relative cost. We illustrate the methodologies on the Serum Alanine-aminotransferase (ALT) available from hospital registry data for samples of males and females. Repeatability is higher among females in comparison to males.
文摘<strong>Objective</strong><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>Since the identification of COVID-19 in December 2019 as a pandemic, over 4500 research papers were published with the term “COVID-19” contained in its title. Many of these reports on the COVID-19 pandemic suggested that the coronavirus was associated with more serious chronic diseases and mortality particularly in patients with chronic diseases regardless of country and age. Therefore, there is a need to understand how common comorbidities and other factors are associated with the risk of death due to COVID-19 infection. Our investigation aims at exploring this relationship. Specifically, our analysis aimed to explore the relationship between the total number of COVID-19 cases and mortality associated with COVID-19 infection accounting for other risk factors. </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: Due to the presence of over dispersion, the Negative Binomial Regression is used to model the aggregate number of COVID-19 cases. Case-fatality associated with this infection is modeled as an outcome variable using machine learning predictive multivariable regression. The data we used are the COVID-19 cases and associated deaths from the start of the pandemic up to December 02-2020, the day Pfizer was granted approval for their new COVID-19 vaccine. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: Our analysis found significant regional variation in case fatality. Moreover, the aggregate number of cases had several risk factors including chronic kidney disease, population density and the percentage of gross domestic product spent on healthcare. </span><b><span style="font-family:Verdana;">The Conclusions</span></b><span style="font-family:Verdana;">: There are important regional variations in COVID-19 case fatality. We identified three factors to be significantly correlated with case fatality</span></span></span></span><span style="font-family:Verdana;">.</span>
文摘The horticultural sector has undergone tremendous growth in Kenya and is now the second largest foreign income earning sector in the country. Lake Naivasha is the hub of large scale horticultural farming in Kenya. This growth coupled with increased use of pesticides, may increase the possibility of pesticide exposure and its associated risks to workers and residents of the region. The purpose of this study was to assess the symptoms commonly experienced by residents of Naivasha town and their possible association to pesticide exposure. Purposive sampling of residents from Kamere, Kwa Muia, Kioto and Karagita was performed, as these residential areas have significant numbers of flower farm workers. By random selection, a total of 801 community members were recruited to participate in the study and data was collected by completing the prepared questionnaire and from clinical examinations. Results indicate that several residents exhibited respiratory;skin, joints and bones;and nervous system symptoms. We found a higher frequency of symptoms among planters, weeders, harvesters than in sprayers working in horticultural farms. We recommend training to planters, weeders, harvesters who are mainly women (61.6%) in this study concerning pesticide use as do sprayers;and second, longer reentry times between the last spraying of pesticide and entry of these workers is warranted, particularly in greenhouses. In this regard, reentry times for greenhouses and fields established for specific pesticides in Europe, North America, Japan or Australia should be adapted by Kenya, and these guidelines enforced by the Government of Kenya to reduce exposure to pesticides within this vulnerable work group. These workers should also use protective clothing including gloves and masks at all times while handling chemicals or recently sprayed plants or flowers. It would also be prudent for flower farm owners to introduce an integrated pest management regime to reduce pesticide use andworker exposures. Further research is required both to identify validated biomarkers that can reliably be used to identify pesticide exposure prior to the occurrence of acute toxicity;and to follow up individual cases of known exposures for chronic health effects.
文摘<span style="font-family:""><span style="font-family:Verdana;">Infection with </span><i><span style="font-family:Verdana;">Toxoplasma gondii</span></i><span style="font-family:Verdana;">, is one of the most widespread zoonoses in the world. Congenital Toxoplasmosis (CT) is particularly risky due to its fetal </span><span style="font-family:Verdana;">complications. Sulfadiazine (SDZ) and Pyrimethamine (PYR) are usually </span><span style="font-family:Verdana;">used </span><span style="font-family:Verdana;">for CT treatment in Argentina, to prevent morbidity. Due to the lack of </span><span style="font-family:Verdana;">commercial pediatric formulations, these must be prepared in the hospital pharmacy. This is the first report of serum concentrations measures in pediatric CT therapy for this combination of drugs. A bioanalytical method was developed for identification and simultaneous quantification of SDZ and PYR by High Performance Liquid Chromatography (HPLC) with UV detection. The validated method was applied to residual serum samples obtained from 6 pediatric patients undergoing treatment with SDZ 42.20 a 93.70 mg/kg/day and </span><span style="font-family:Verdana;">PYR 0.77 a 2.70 mg/kg/day. Sample pretreatment consisted </span></span><span style="font-family:Verdana;">on</span><span style="font-family:Verdana;"> a</span><span style="font-family:""><span style="font-family:Verdana;"> deproteini</span><span style="font-family:Verdana;">zation step followed by centrifugation and then injection of supernatant.</span><span style="font-family:Verdana;"> Limit of Detection (LOD) and Quantification (LOQ) were (0.17 ± 0.02 and 0.13 ± 0.02) μg/mL and (0.46 ± 0.01 and 0.36 ± 0.01) μg/mL for SDZ and PYR respectively, with an appropriate linear range. Concentrations range found </span><span style="font-family:Verdana;">were (<LOD</span></span><span style="font-family:Verdana;"> - </span><span style="font-family:Verdana;">162.04 ± 0.02) μg/mL for SDZ and (<LOD</span><span style="font-family:Verdana;"> - </span><span style="font-family:Verdana;">7.30 ± 0.03) </span><span style="font-family:""><span style="font-family:Verdana;">μg/mL for PYR. We developed and validated in real pediatric samples, an acute, pre</span><span style="font-family:Verdana;">cise and low-cost method for quantification of SDZ and PYR using a </span><span style="font-family:Verdana;">non-so</span><span style="font-family:Verdana;">phisticate chromatographic equipment, suitable for hospital therapeutic </span><span style="font-family:Verdana;">monitoring for public health system.
文摘Objectives: We introduce a special form of the Generalized Poisson Distribution. The distribution has one parameter, yet it has a variance that is larger than the mean a phenomenon known as “over dispersion”. We discuss potential applications of the distribution as a model of counts, and under the assumption of independence we will perform statistical inference on the ratio of two means, with generalization to testing the homogeneity of several means. Methods: Bayesian methods depend on the choice of the prior distributions of the population parameters. In this paper, we describe a Bayesian approach for estimation and inference on the parameters of several independent Inflated Poisson (IPD) distributions with two possible priors, the first is the reciprocal of the square root of the Poisson parameter and the other is a conjugate Gamma prior. The parameters of Gamma distribution are estimated in the empirical Bayesian framework using the maximum likelihood (ML) solution using nonlinear mixed model (NLMIXED) in SAS. With these priors we construct the highest posterior confidence intervals on the ratio of two IPD parameters and test the homogeneity of several populations. Results: We encountered convergence problem in estimating the hyperparameters of the posterior distribution using the NLMIXED. However, direct maximization of the predictive density produced solutions to the maximum likelihood equations. We apply the methodologies to RNA-SEQ read count data of gene expression values.
文摘Objective: We aim to detect over-time variations in mortality of liver transplant recipients stratified by the period of transplant. Since this is a retrospective investigation, bias reduction caused by possible confounding effects can be achieved by using propensity score weighting in a multivariate logistic regression model. Methods: Medical charts of all adult liver transplant recipients (n = 250) who were transplanted in three periods 2005-2009, 2010-2014 and 2015-2019 were retrospectively reviewed. The following recipient factors were analyzed: recipients and donors’ ages, sex, renal impairment, body mass index (BMI), presence of bacterial or viral infections, MELD (Model for end-stage diseases). Multivariate logistic model adjusted by Propensity Scores (PS) was used to identify the effect of the risk factors on mortality, and death within five years, in the targeted time frame. Patient outcomes are recorded as;(patient status = 1 if dead, or patient status = 0 if alive). Results: Meld score, recipient age, and renal impairments were shown to be predictors of mortality in transplanted patients. Multivariate regression model was used to identify the significance of the specified risk factors, followed by pairwise comparisons between periods. Pairwise comparisons between periods using logistic regression weighted by the inverse propensity score, correcting for the possible confounding effect of measured covariates showed that the death rate is significantly reduced in subsequent periods as compared to the initial period. Conclusions: The clinical implications of these findings are the ability to stratify patients at high risk of posttransplant death by planning more intensive and accurate management for them.
文摘Background: When continuous scale measurements are available, agreements between two measuring devices are assessed both graphically and analytically. In clinical investigations, Bland and Altman proposed plotting subject-wise differences between raters against subject-wise averages. In order to scientifically assess agreement, Bartko recommended combining the graphical approach with the statistical analytic procedure suggested by Bradley and Blackwood. The advantage of using this approach is that it enables significance testing and sample size estimation. We noted that the direct use of the results of the regression is misleading and we provide a correction in this regard. Methods: Graphical and linear models are used to assess agreements for continuous scale measurements. We demonstrate that software linear regression results should not be readily used and we provided correct analytic procedures. The degrees of freedom of the F-statistics are incorrectly reported, and we propose methods to overcome this problem by introducing the correct analytic form of the F statistic. Methods for sample size estimation using R-functions are also given. Results: We believe that the tutorial and the R-codes are useful tools for testing and estimating agreement between two rating protocols for continuous scale measurements. The interested reader may use the codes and apply them to their available data when the issue of agreement between two raters is the subject of interest.
基金This case report was funded by Psychosomatic Medicine Project of Key Developing Disciplines of Shanghai Municipal Health Commission(2019ZB0202)in China.
文摘Restless legs syndrome(RLS)is a common sleep-related movement disorder characterised by an uncomfortable urge to move the legs that occurs during periods of inactivity.Although there have been many case reports on antipsychotic-induced RLS,ziprasidone has never been reported as a cause of RLS.We present a case of a female patient with schizophrenia who presented with symptoms of RLS following the administration of high doses of ziprasidone added to quetiapine and valproate.The patient’s symptoms of RLS occurred following the administration and titration of ziprasidone to 160 mg,and were relieved upon reducing the dose to 120 mg/day.Other potential causative medications and differential diagnoses that could have caused similar symptoms were excluded.Clinicians should be aware of the potential for ziprasidone-induced RLS.Dopamine and serotonin interaction could be the mechanism underlying ziprasidone-induced RLS.
文摘The therapeutic properties of Lactobacillus rhamnosus GR-1 and ginseng extracts have been well documented. The objective of this study was to measure growth and survival of L. rhamnosus GR-1 in milk fortified with ginseng extracts during storage period of 28 days. Five formulations of milk (1% fat) were prepared. Two samples were fortified with alcoholic ginseng extract (AGE: 150 μg/mL, AGE: 500 μg/mL) and the other two samples were fortified with aqueous ginseng extract (QGE: 150 μg/mL, QGE: 500 μg/ml) and one with no ginseng extract (C). The mixtures were autoclaved for 15 min, cooled to 37?C and inoculated with 1% starter culture. The samples were then incubated anaerobically at 37℃ overnight. Selective MRS agar containing 0.015 g/L fusidic acid was used to enumerate L. rhamnosus GR-1 after 1, 14, and 28 d storage at 4℃. All ginseng-fortified samples supported the growth and survival of L. rhamnosus GR-1, as viable counts were detected at each measurement point throughout the 28 d storage period. After 1 d of storage, total colony counts for L. rhamnosus GR-1 in AGE: 150 μg/mL and AGE: 500 μg/mL were 1.3 × 109 and 1.4 × 109 CFU/mL, respectively;probiotic counts in QGE 150 μg/mL and QGE: 500 μg/mL were 1.5 × 109 and 1.4 × 109 CFU/mL, respectively. Additionally, L. rhamnosus GR-1 viability remained stable throughout the 28 days storage period, as no significant decrease (p L. rhamnosus GR-1 can remain viable in presence of ginseng extracts during storage period and there is potential for incorporating ginseng extracts in other probiotic dairy products.
文摘Dear editor,Dr.Peter Drummond’s article noted that peripheral nerve and tissue injury in neuropathic pain syndromes releases cytokines which in turn lead to an increase in alpha1-adrenoceptor upregulation,resulting in a heightened sensitivity to noradrenaline.In these circumstances,noradrenaline acting on upregulated alpha1a-adrenoceptors increases the release of cytokine interleukin-6.Hence,nociceptive afferent neurons exposed to injury induced cytokines become more hypersensitive to noradrenaline。
文摘Background: Factors associated with hospital mortality are usually identified and their effects are quantified through statistical modeling. To guide the choice of the best statistical model, we first quantify the predictive ability of each model and then use the CIHI index to see if the hospital policy needs any change. Objectives: The main purpose of this study compared three statistical models in the evaluation of the association between hospital mortality and two risk factors, namely subject’s age at admission and the length of stay, adjusting for the effect of Diagnostic Related Groups (DRG). Methods: We use several SAS procedures to quantify the effect of DRG on the variability in hospital mortality. These procedures are the Logistic Regression model (ignoring the DRG effect), the Generalized Estimating Equation (GEE) that takes into account the within DRG clustering effect (but the within cluster correlation is treated as nuisance parameter), and the Generalized Linear Mixed Model (GLIMMIX). We showed that the GLIMMIX is superior to other models as it properly accounts for the clustering effect of “Diagnostic Related Groups” denoted by DRG. Results: The GLM procedure showed that the proportional contribution of DRG is 16%. All three models showed significant and increasing trend in mortality (P < 0.0001) with respect to the two risk factors (age at admission, and hospital length of stay). It was also clear that the CIHI index was not different under the three models. We re-estimated the models parameters after dichotomizing the risk factors at the optimal cut-off points, using the ROC curve. The parameters estimates and their significance did not change.
文摘<strong>Background: </strong><span style="font-family:""><span style="font-family:Verdana;">One of the main objectives of hospital managements is to control the length of stay (LOS). Successful control of LOS of inpatients will result in reduction in the cost of care, decrease in nosocomial infections, medication side effects, and better management of the limited number of available patients’ beds. The length of stay (LOS) is an important indicator of the efficiency of hospital management by improving the quality of treatment, and increased hospital profit with more efficient bed management. The purpose of this study was to model the distribution of LOS as a function of patient’s age, and the Diagnosis Related Groups (DRG), based on electronic medical records of a large tertiary care hospital. </span><b><span style="font-family:Verdana;">Materials and Methods: </span></b><span style="font-family:Verdana;">Information related to the research subjects were retrieved from a database of patients admitted to King Faisal Specialist Hospital and Research Center hospital in Riyadh, Saudi Arabia between January 2014 and December 2016. Subjects’ confidential information was masked from the investigators. The data analyses were reported visually, descriptively, and analytically using Cox proportional hazard regression model to predict the risk of long-stay when patients’ age and the DRG are considered as antecedent risk factors. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">Predicting the risk of long stay depends significantly on the age at admission, and the DRG to which a patient belongs to. We demonstrated the validity of the Cox regression model for the available data as the proportionality assumption is shown to be satisfied. Two examples were presented to demonstrate the utility of the Cox model in this regard.</span></span>
文摘Count data that exhibit over dispersion (variance of counts is larger than its mean) are commonly analyzed using discrete distributions such as negative binomial, Poisson inverse Gaussian and other models. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial and the Poisson inverse Gaussian have variance larger than the mean and therefore are more appropriate to model over-dispersed count data. As an alternative to these two models, we shall use the generalized Poisson distribution for group comparisons in the presence of multiple covariates. This problem is known as the ANCOVA and is solved for continuous data. Our objectives were to develop ANCOVA using the generalized Poisson distribution, and compare its goodness of fit to that of the nonparametric Generalized Additive Models. We used real life data to show that the model performs quite satisfactorily when compared to the nonparametric Generalized Additive Models.
文摘Background: The Poisson and the Negative Binomial distributions are commonly used to model count data. The Poisson is characterized by the equality of mean and variance whereas the Negative Binomial has a variance larger than the mean and therefore both models are appropriate to model over-dispersed count data. Objectives: A new two-parameter probability distribution called the Quasi-Negative Binomial Distribution (QNBD) is being studied in this paper, generalizing the well-known negative binomial distribution. This model turns out to be quite flexible for analyzing count data. Our main objectives are to estimate the parameters of the proposed distribution and to discuss its applicability to genetics data. As an application, we demonstrate that the QNBD regression representation is utilized to model genomics data sets. Results: The new distribution is shown to provide a good fit with respect to the “Akaike Information Criterion”, AIC, considered a measure of model goodness of fit. The proposed distribution may serve as a viable alternative to other distributions available in the literature for modeling count data exhibiting overdispersion, arising in various fields of scientific investigation such as genomics and biomedicine.
文摘Objectives: Developing inference procedures on the quasi-binomial distribution and the regression model. Methods: Score testing and the method of maximum likelihood for regression parameters estimation. Data: Several examples are included, based on published data. Results: A quasi-binomial model is used to model binary response data which exhibit extra-binomial variation. A partial score test on the binomial hypothesis versus the quasi-binomial alternative is developed and illustrated on three data sets. The extended logit transformation on the binomial parameter is introduced and the large sample dispersion matrix of the estimated parameters is derived. The Nonlinear Mixed Procedure (NLMIXED) in SAS is shown to be very appropriate for the estimation of nonlinear regression.
文摘Background: Cardiovascular diseases (CVDs) are the leading cause of death globally. An estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Of these deaths, 85% were due to heart attack and stroke. Over three quarters of CVD deaths take place in low- and middle-income countries. We have studied the pattern of mortality due to cardiovascular in the six countries of the Arabian Gulf and its association with obesity over the 29 years 1990 to 2019. Methods: We used the linear mixed effect models to investigate the pattern of CVD mortality over the year 1990 to 2019, together with the pattern of change in one of the most important risk factors that is obesity, and its association with CVD mortality over the same period. Conclusions: Although there were fluctuations in the pattern of mortality and the prevalence of obesity over the specified period, there has been a steady decline in the per-100,000 number of deaths and the prevalence of obesity. However, there was a strong association between the two variables. From the fitted models we estimated that a one percent increase in obesity is associated with an average increase in cardiovascular deaths of 2.7 deaths per 100,000.
文摘Objective:The holmium:yttrium-aluminium-garnet laser(Ho:YAG)has been the gold standard for laser lithotripsy over the last three decades.After demonstrating good in vitro efficacy,the thulium fiber laser(TFL)has been recently released in the market and the initial clinical results are encouraging.This article aims to review the main technology differences between the Ho:YAG laser and the TFL,discuss the initial clinical results with the TFL as well as the optimal settings for TFL lithotripsy.Methods:We reviewed the literature focusing on the technological aspects of the Ho:YAG laser and TFL as well as the results of in vitro and in vivo studies comparing both technologies.Results:In vitro studies show a technical superiority of TFL compared to the Ho:YAG laser and encouraging results have been demonstrated in clinical practice.However,as TFL is a new technology,limited studies are currently available,and the optimal settings for lithotripsy are not yet established.Conclusion:TFL has the potential to be an alternative to the Ho:YAG laser,but more reports are still needed to determine the optimal laser for lithotripsy of urinary tract stones when considering all parameters including effectiveness,safety,and costs.
