Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance li...Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance liquid chromatography (HPLC) was used to isolate and quantitate MT in livers of minks which were contaminated with heavy metals. MT isoforms (MT-I and MT-II) were eluted at approximately 11.3 and 14.3 min respectively from a DEAE-5 PW anion-exchange column with a Tris-HCl buffer (0.01 -0.25 mol/L, pH 8.6) and detected by UV absorbance at 254 nm. The cadmium concentrations in mink liver MT elutkms were determined by graphite furnace atomic absorption spectrometry (GFAAS) . Obvious increase in liver MT-I concentration rather than liver MT-II was found when the minks were contaminated by feeding contaminated fish captured from the heavy metal-polluted river. The cadmium concentration in mink liver MT-I also increased to some extent as the contaminated level increased.展开更多
A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 ...A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 dalton.a UV absorption peak at 260 instead of 280 nm like most proteins;andhas high affinity towards binding with radioactive labeled <sup>109</sup>Cd.These characteristics are similarto that of metallothioneins reported for many vertebrate and invertebrate,marine and terrestrialanimals.After the brine shrimp is exposed to a small amount of Cd<sup>2+</sup>for 24 h,a large amount ofmetallothionein can be isolated,showing the inducibility of this detoxifying protein in the adult Artemiain a short period of time.展开更多
Metallothionein (MT) is a low molecular weigh t (MW ) and heatstable metal-- binding pro- tein. It has been proved that the synthesis of MT in marine animals can be induced by various heavy metals at genetic level. Co...Metallothionein (MT) is a low molecular weigh t (MW ) and heatstable metal-- binding pro- tein. It has been proved that the synthesis of MT in marine animals can be induced by various heavy metals at genetic level. Consequently, high level of MT can be used as sign of heavy metal pollution. In this article, red scorponifish m was purified by Sephadex G -- 75 gel filtration and DEAE- Sepharose CL -- 6B ion exchange chromatography. The results of amino acids composition analysis showed that the protein contains 35 % cysteine(Cys), but no aromatic residues. MW was about 6.7 kD, and pI is 4. 0 and 4. 2, respectively. The antibody was raised in white rabbits by injection by MT conjugated with BSA, and then purified on Protein A beads and labeled with horseradish peroxidase. Quantification of MT by ELISA indicated that the concentration of MT from induced and noninduced fish liver extraction were 450 and 20 ug/cm3, respectively.展开更多
99mTc-labelled metallothionein (99mTc-MT) was prepared through both direct and transcomplexation labelling approaches. Buffer systems and a variety of other parameters in the direct labelling procedure were studied in...99mTc-labelled metallothionein (99mTc-MT) was prepared through both direct and transcomplexation labelling approaches. Buffer systems and a variety of other parameters in the direct labelling procedure were studied in detail. High radiolabelling yields of 93-96% and the specific radioactivity of 3.7 MB/μg were obtained under optimal conditions by the direct labelling method. The prepared 99mTc-MT was stable in vitro. The chelate-exchange kinetics of MT with 99mTc-glucohepatonate and 99mTc-citrate were also studied. Biodistribution and imaging studies showed that 99mTc-MT was accumulated in the animal kidneys at an exceptionally high level, indicating that 99mTc-MT might be a potential renal imaging agent.展开更多
Cd, Zn-thionelns were isolated from the rat liver by improved Winge method and purified further. The composition was determined. The mobilization of Cd ions from the Cd, Zn-metallothioneins was studied with spectropho...Cd, Zn-thionelns were isolated from the rat liver by improved Winge method and purified further. The composition was determined. The mobilization of Cd ions from the Cd, Zn-metallothioneins was studied with spectrophotometric method. The results show that the reaction of DTP A or EDTA with Cd, Zn-thioneins occurs through three steps. The first step follows pseudo-first order reaction with association mechanism. The formation constants and the dissociation rate constants of the relevant intermediate ternary complexes and apparent rate constants, Kapp were determined. The properties and structure of Cd, Zn-thioneins and ligands with low molecular weights affect the values of Kapp.展开更多
Metallothionein (MT) gene has an important role in the detoxification of toxic metals especially some heavy metals. Based on the published sequences of MT genes from Agaricus bisporus, Garnoderma lucidum, Taiwanofungu...Metallothionein (MT) gene has an important role in the detoxification of toxic metals especially some heavy metals. Based on the published sequences of MT genes from Agaricus bisporus, Garnoderma lucidum, Taiwanofungus camphoratus and Paxillus involutus as a type of the edible or medical mushroom in NCBI database, their molecular structures, physiological functions and evolutionary relationship were analyzed using the bioinformatics methods. Results showed that AbMT, GlMT, TcMT and PiMT genes contained complete open reading frame (ORF) and their theoretical points of the last three encoding proteins were higher than 7.0. AbMT, GlMT, TcMT and PiMT were relatively rich in random coil and extended strand, but transmembrane helices and signal peptides were not found. 4 MTs were mainly localized in cell nucleus (over 60%) and their cellular functions might have some relation to central intermediary metabolism. Multiple sequence alignment indicated relatively high identity (more than 52%) and short genetic distances (lower than 0.900) among 4 MT nucleotide sequences. Abundant genetic diversity and strong codon bias were found based on the halotype diversity, average number of nucleotide differences, nucleotide diversity, effective number of codons, codon bias index and scaled chisquare. Simultaneously, we deduced that 4 MT genes during molecular evolution were under positive selection. The present study might provide basis for further investigation of MTs molecular mechanisms and genetic laws.展开更多
Objective:To explore the role of metallothionein-3 gene in lung adenocarcinoma. Methods:cDNA microarray and northern blots analysis were used to study the expression of metallothionein-3 in lung adenocarcinoma. Result...Objective:To explore the role of metallothionein-3 gene in lung adenocarcinoma. Methods:cDNA microarray and northern blots analysis were used to study the expression of metallothionein-3 in lung adenocarcinoma. Results: The results of cDNA microarray showed that metallothionein-3 gene was expressed highly to normal lung tissues at the average ratio of 7.8 (Cy5/Cy3) in lung adenocarcinoma tissues. Northern blots confirmed the ratio changes detected from the microarray. Conclusion: Metallothionein-3 may play an important role in the lung adenocarcinoma development.展开更多
AIM: To illustrate the pathophysiological role of metallothionein (MT) in gastric ulcer induced by stress. METHODS: Wistar rats underwent water-immersionrestraint (WIR) stress, ZnSO4 (an MT inducer) treatment, WIR+ZnS...AIM: To illustrate the pathophysiological role of metallothionein (MT) in gastric ulcer induced by stress. METHODS: Wistar rats underwent water-immersionrestraint (WIR) stress, ZnSO4 (an MT inducer) treatment, WIR+ZnSO4 or WIR+MT, and the ulcer index (UI) was estimated in excised stomach and liver tissues. The mRNA level of gastric MT was determined by semi-quantitative RT-PCR. The MT content in gastric and hepatic tissues was determined by Cd/hemoglobin affinity assay. The lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CD) were estimated by use of thiobarbituric acid reactive species and ultraviolet spectrophotometry. RESULTS: WIR stress induced severe gastric mucosal lesions in rats. Compared with control rats, stressed rats had increased lipid peroxide content in serum and stomach and liver tissues. MDA content was increased by 34%, 21% and 29% and CD level by 270%, 83% and 28%, respectively. MT content in the stomach and liver was increased by 0.74- and 1.8-fold, and the MT-mRNA level in the stomach was increased by 26%. Pretreatment with ZnSO4 prevented gastric lesion development (the UI was 87% lower than that without pretreatment), and the MDA and CD content in serum and tissues was lower. The MT content in the liver was double in rats that were not pretreated, and the MT mRNA level in the stomach was 35% higher. MT administration 1 h before the WIR stress prevented gastric lesion development (the UI decreased by 47% compared with that in rats not pretreated), and the MDA and CD content in serum and tissues was significantly lower. CONCLUSION: In WIR-stressed rats, the MT level was increased in serum and in stomach and liver tissues. Pre-administration of exogenous MT or pre-induction of endogenous MT can protect the gastric mucosa against stress-induced ulcers and inhibits the formation of stressinduced lipid peroxide. MT could have a gastroprotective effect and might be a new interventive and therapeutic target in stress-induced gastric ulcers.展开更多
AIM: Esophageal squamous cell carcinoma is generally sensitive to chemoradiotherapy (CRT), but some cases are not. Using a retrospective analysis, we aimed to identify the predictors of the response by esophageal squa...AIM: Esophageal squamous cell carcinoma is generally sensitive to chemoradiotherapy (CRT), but some cases are not. Using a retrospective analysis, we aimed to identify the predictors of the response by esophageal squamous cell carcinoma to definitive CRT.METHODS: The intensities of expression of p53, Ki67,Bcl-2, Bax, cyclin D1, VEGF, CDC25B, and metallothionein (MT)were evaluated immunohistochemically in the biopsy specimens obtained before CRT, and the intensities of their expression were tested for correlations with the clinical effects of CRT.RESULTS: The esophageal squamous cell carcinomas with negative p53, positive CDC25B, and negative MT expression were found to be significantly more sensitive to CRT. In addition, p53 positivity and CDC25B positivity respomd well to CRT.CONCLUSION: Esophageal squamous cell carcinomas with negative p53,positive CDC25B, and negative MT expressions respond well to CRT. Even with p53 positivity,if with CDC25B positivity, CRT can be expected.展开更多
AIM:To investigate the role of p53 antibodies (p53Abs),metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).METHODS:The study included 30 UC patien...AIM:To investigate the role of p53 antibodies (p53Abs),metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).METHODS:The study included 30 UC patients,15 without dysplasia (group Ⅱ) and 15 with dysplasia (group Ⅲ),in addition to 15 healthy volunteers (group Ⅰ,control subjects).The enzyme-linked immunosorbent assay technique was used to measure serum p53Abs and MTs,while advanced oxidation protein products (AOPPs),and reduced glutathione (GSH) levels were measured by spectrophotometric method in all subjects.RESULTS:In group Ⅱ and group Ⅲ compared to group Ⅰ,there were significant increases in serum levels of AOPPs (145.94 ± 29.86 μmol/L and 192.21 ± 46.71 μmol/L vs 128.95 ± 3.06 μmol/L,P < 0.002 and P <0.001,respectively),MTs (8.18 ± 0.35 μg/mL and 9.20 ± 0.58 μg/mL vs 6.12 ± 0.25 μg/mL,P < 0.05 and P < 0.05,respectively),and p53Abs (20.19 ± 3.20 U/mL and 34.66 ± 1.34 U/mL vs 9.42 ± 1.64 U/mL,P < 0.001 and P < 0.001,respectively).There were significantly higher levels of AOPPs (P < 0.05) and p53Abs (P < 0.001) in UC patients with dysplasia compared to those without dysplasia,while MTs showed no significant difference between the 2 groups (P > 0.096).In contrast,GSH levels showed a significant decrease in both patients' groups (1.87 ± 0.02 μmol/mL and 1.37 ± 0.09 μmol/mL vs 2.49 ± 0.10 μmol/mL,P < 0.05 and P < 0.05 in groups Ⅱ and Ⅲ,respectively) compared with group Ⅰ,and the levels were significantly lower in group Ⅲ than group Ⅱ (P < 0.05).There was a positive correlation between AOPPs and both MTs (r=0.678,P < 0.001) and p53Abs (r=0.547,P < 0.001),and also between p53Abs and MTs (r=0.739,P < 0.001).There was a negative correlation between AOPPs and GSH (r =-0.385,P < 0.001),and also between GSH and both MTs (r=-0.662,P < 0.001) and p53Abs (r=-0.923,P < 0.001).CONCLUSION:Oxidative stress and oxidative cellular damage play an important role in the pathogenesis of chronic UC and the associated carcinogenetic process.p53Abs levels could help in early detection of dysplasia in these conditions.展开更多
Metallothioneins (MTs) were discovered in 1957 by Margoshes and Vallee and identified as low-molecular weight and sulphydryl rich proteins. It is not surprising that most mammalian tissues contain age related basal le...Metallothioneins (MTs) were discovered in 1957 by Margoshes and Vallee and identified as low-molecular weight and sulphydryl rich proteins. It is not surprising that most mammalian tissues contain age related basal levels of MTs since they are involved in metalloregulatory processes that include cell growth and multiplication. In an effort to understand the biology of this intriguing tumor, various biomarkers such as oncogenes, p53 tumor suppressor gene, waf 1 protein, proliferating cell nuclear antigen, telomerase, microsatellite markers and cytogenetic changes have been examined. One biomarker which has recently shown to be expressed in various human tumors but still less reported in carcinoma is MT. Immunohistochemical detection of MT proteins in cold acetone-fixed paraffin embedded liver sections was performed by the streptavidin-avidin-biotin immuno- peroxidase complex method.展开更多
AIM: To examine the effect of increasing dietary zinc (Zn) intake and the lack of metallothionein (MT) expression on activity of small intestinal disaccharidases. METHODS: MT-Ⅰ and Ⅱ knockout (MT-/-) and wild-type (...AIM: To examine the effect of increasing dietary zinc (Zn) intake and the lack of metallothionein (MT) expression on activity of small intestinal disaccharidases. METHODS: MT-Ⅰ and Ⅱ knockout (MT-/-) and wild-type (MT+/+) female mice at 3.5 wk of age were randomly fed with a diet containing 2 (2 Zn), 15 (15 Zn) or 50 (50 Zn) mg Zn/kg (n = 8/group/genotype) for 5 wk. Small intestinal segments (duodenum, jejunum and ileum) were collected and either fixed in 10% formalin for histological analysis or snap frozen in liquid nitrogen for sucrase, lactase and maltase activity analyses.RESULTS: Plasma Zn was significantly (P < 0.05) lower (33%) in MT-/- compared with MT+/+ mice fed the 2 Zn diet. Villus height and crypt depth were increased by approximately 15% in MT+/+ mice compared with MT-/- mice. Duodenal disaccharidase activities were significantly higher in MT+/+ compared with MT-/- mice particularly in those fed the 2 Zn diet. For the 50 Zn diet, jejunal sucrase and lactase activities were significantly higher in MT-/- (13 313 ± 2314; 4107 ± 364 μmol glucose/well/min/g tissue, respectively) compared with MT+/+ mice (7054 ± 608; 1818 ± 174). Similarly, ileal lactase activities were higher in MT-/- (1480 ± 192) compared with MT+/+ (629 ± 353) mice particularly those fed the 2 Zn diet. CONCLUSION: Increasing dietary Zn has little effect on disaccharidases activity in MT wild-type mice. The presence of MT may enhance morphological and functional development of the gut.展开更多
Metallothioneins(MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions.A cadmium metallothionein(EcMT-Cd) cDNA with a 189 bp open reading frame(ORF) that encoded a 62 amin...Metallothioneins(MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions.A cadmium metallothionein(EcMT-Cd) cDNA with a 189 bp open reading frame(ORF) that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda.Seventeen cysteines were in the deduced amino acid sequence,and the cysteine(Cys)-rich characteristic was revealed in different metallothioneins in other species.In addition,the deduced amino acid sequence did not contain any aromatic amino acid residues,such as tyrosine(Tyr),tryptophan(Trp),and phenylalanine(Phe).EcMTCd mRNA was expressed in all tested tissues(the ovary,muscle,stomach,and hepatopancreas),and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50μmol/L CuSO4or 2.5μmol/L CdCl2.The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4for 12 h and down-regulated in shrimps exposed to CdCl2for 12 h.After 24 h exposure to both metals,its expression was down-regulated.By contrast,at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdCl2.The transcript of EcMT-Cd was very low or even absent before the zoea stage,and the expression of EcMT-Cd was detected from mysis larvae-I,then its expression began to rise.In conclusion,a cadmium MT exists in E.carinicauda that is expressed in different tissues and during different developmental stages,and responds to the challenge with heavy metal ions,which provides a clue to understanding the function of cadmium MT.展开更多
Objective: To study the expressions and significations of metallothionein (MT) in cervical squamous cell cancer (CSC), bladder transitional cell cancer (BTC) and breast cancer (BC) of woman. Methods: Immunohistochemic...Objective: To study the expressions and significations of metallothionein (MT) in cervical squamous cell cancer (CSC), bladder transitional cell cancer (BTC) and breast cancer (BC) of woman. Methods: Immunohistochemical method was used to examine the expresses rate of MT in three types of woman cancer tissue. Results: The expressions rates of MT were 54.35% (29/46) in BTC, 67.05% (59/88) in BC and 57.14% (40/70) in CSC. The positive rate of MT expression was higher in low differentiation group than well differentiation group in BTC and CSC (P < 0.05). Positive of MT in lobular cancer was significance higher than medullary and duct cancers (P < 0.05). Conclusion: The expression of MT is related to differentiation degree, and it is a guidance for clinical choice of chemotherapy project.展开更多
文摘Metallothionein (MT) has a great capacity of binding heavy metals showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution. Anino-exchange high per formance liquid chromatography (HPLC) was used to isolate and quantitate MT in livers of minks which were contaminated with heavy metals. MT isoforms (MT-I and MT-II) were eluted at approximately 11.3 and 14.3 min respectively from a DEAE-5 PW anion-exchange column with a Tris-HCl buffer (0.01 -0.25 mol/L, pH 8.6) and detected by UV absorbance at 254 nm. The cadmium concentrations in mink liver MT elutkms were determined by graphite furnace atomic absorption spectrometry (GFAAS) . Obvious increase in liver MT-I concentration rather than liver MT-II was found when the minks were contaminated by feeding contaminated fish captured from the heavy metal-polluted river. The cadmium concentration in mink liver MT-I also increased to some extent as the contaminated level increased.
文摘A small amount of heavy metal binding protein,identified by BioRad Protein Assay,has been iso-lated from the adult brine shrimp,Artemia franciscanus.This protein has an apparent molecular weight be-tween 6000 to 9000 dalton.a UV absorption peak at 260 instead of 280 nm like most proteins;andhas high affinity towards binding with radioactive labeled <sup>109</sup>Cd.These characteristics are similarto that of metallothioneins reported for many vertebrate and invertebrate,marine and terrestrialanimals.After the brine shrimp is exposed to a small amount of Cd<sup>2+</sup>for 24 h,a large amount ofmetallothionein can be isolated,showing the inducibility of this detoxifying protein in the adult Artemiain a short period of time.
文摘Metallothionein (MT) is a low molecular weigh t (MW ) and heatstable metal-- binding pro- tein. It has been proved that the synthesis of MT in marine animals can be induced by various heavy metals at genetic level. Consequently, high level of MT can be used as sign of heavy metal pollution. In this article, red scorponifish m was purified by Sephadex G -- 75 gel filtration and DEAE- Sepharose CL -- 6B ion exchange chromatography. The results of amino acids composition analysis showed that the protein contains 35 % cysteine(Cys), but no aromatic residues. MW was about 6.7 kD, and pI is 4. 0 and 4. 2, respectively. The antibody was raised in white rabbits by injection by MT conjugated with BSA, and then purified on Protein A beads and labeled with horseradish peroxidase. Quantification of MT by ELISA indicated that the concentration of MT from induced and noninduced fish liver extraction were 450 and 20 ug/cm3, respectively.
文摘99mTc-labelled metallothionein (99mTc-MT) was prepared through both direct and transcomplexation labelling approaches. Buffer systems and a variety of other parameters in the direct labelling procedure were studied in detail. High radiolabelling yields of 93-96% and the specific radioactivity of 3.7 MB/μg were obtained under optimal conditions by the direct labelling method. The prepared 99mTc-MT was stable in vitro. The chelate-exchange kinetics of MT with 99mTc-glucohepatonate and 99mTc-citrate were also studied. Biodistribution and imaging studies showed that 99mTc-MT was accumulated in the animal kidneys at an exceptionally high level, indicating that 99mTc-MT might be a potential renal imaging agent.
基金This study was supported by National Natural Science Foundation of China.
文摘Cd, Zn-thionelns were isolated from the rat liver by improved Winge method and purified further. The composition was determined. The mobilization of Cd ions from the Cd, Zn-metallothioneins was studied with spectrophotometric method. The results show that the reaction of DTP A or EDTA with Cd, Zn-thioneins occurs through three steps. The first step follows pseudo-first order reaction with association mechanism. The formation constants and the dissociation rate constants of the relevant intermediate ternary complexes and apparent rate constants, Kapp were determined. The properties and structure of Cd, Zn-thioneins and ligands with low molecular weights affect the values of Kapp.
文摘Metallothionein (MT) gene has an important role in the detoxification of toxic metals especially some heavy metals. Based on the published sequences of MT genes from Agaricus bisporus, Garnoderma lucidum, Taiwanofungus camphoratus and Paxillus involutus as a type of the edible or medical mushroom in NCBI database, their molecular structures, physiological functions and evolutionary relationship were analyzed using the bioinformatics methods. Results showed that AbMT, GlMT, TcMT and PiMT genes contained complete open reading frame (ORF) and their theoretical points of the last three encoding proteins were higher than 7.0. AbMT, GlMT, TcMT and PiMT were relatively rich in random coil and extended strand, but transmembrane helices and signal peptides were not found. 4 MTs were mainly localized in cell nucleus (over 60%) and their cellular functions might have some relation to central intermediary metabolism. Multiple sequence alignment indicated relatively high identity (more than 52%) and short genetic distances (lower than 0.900) among 4 MT nucleotide sequences. Abundant genetic diversity and strong codon bias were found based on the halotype diversity, average number of nucleotide differences, nucleotide diversity, effective number of codons, codon bias index and scaled chisquare. Simultaneously, we deduced that 4 MT genes during molecular evolution were under positive selection. The present study might provide basis for further investigation of MTs molecular mechanisms and genetic laws.
文摘Objective:To explore the role of metallothionein-3 gene in lung adenocarcinoma. Methods:cDNA microarray and northern blots analysis were used to study the expression of metallothionein-3 in lung adenocarcinoma. Results: The results of cDNA microarray showed that metallothionein-3 gene was expressed highly to normal lung tissues at the average ratio of 7.8 (Cy5/Cy3) in lung adenocarcinoma tissues. Northern blots confirmed the ratio changes detected from the microarray. Conclusion: Metallothionein-3 may play an important role in the lung adenocarcinoma development.
基金Supported by the State Major Basic Research Development Program of the People's Republic of China, No. 2003CCA041
文摘AIM: To illustrate the pathophysiological role of metallothionein (MT) in gastric ulcer induced by stress. METHODS: Wistar rats underwent water-immersionrestraint (WIR) stress, ZnSO4 (an MT inducer) treatment, WIR+ZnSO4 or WIR+MT, and the ulcer index (UI) was estimated in excised stomach and liver tissues. The mRNA level of gastric MT was determined by semi-quantitative RT-PCR. The MT content in gastric and hepatic tissues was determined by Cd/hemoglobin affinity assay. The lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CD) were estimated by use of thiobarbituric acid reactive species and ultraviolet spectrophotometry. RESULTS: WIR stress induced severe gastric mucosal lesions in rats. Compared with control rats, stressed rats had increased lipid peroxide content in serum and stomach and liver tissues. MDA content was increased by 34%, 21% and 29% and CD level by 270%, 83% and 28%, respectively. MT content in the stomach and liver was increased by 0.74- and 1.8-fold, and the MT-mRNA level in the stomach was increased by 26%. Pretreatment with ZnSO4 prevented gastric lesion development (the UI was 87% lower than that without pretreatment), and the MDA and CD content in serum and tissues was lower. The MT content in the liver was double in rats that were not pretreated, and the MT mRNA level in the stomach was 35% higher. MT administration 1 h before the WIR stress prevented gastric lesion development (the UI decreased by 47% compared with that in rats not pretreated), and the MDA and CD content in serum and tissues was significantly lower. CONCLUSION: In WIR-stressed rats, the MT level was increased in serum and in stomach and liver tissues. Pre-administration of exogenous MT or pre-induction of endogenous MT can protect the gastric mucosa against stress-induced ulcers and inhibits the formation of stressinduced lipid peroxide. MT could have a gastroprotective effect and might be a new interventive and therapeutic target in stress-induced gastric ulcers.
文摘AIM: Esophageal squamous cell carcinoma is generally sensitive to chemoradiotherapy (CRT), but some cases are not. Using a retrospective analysis, we aimed to identify the predictors of the response by esophageal squamous cell carcinoma to definitive CRT.METHODS: The intensities of expression of p53, Ki67,Bcl-2, Bax, cyclin D1, VEGF, CDC25B, and metallothionein (MT)were evaluated immunohistochemically in the biopsy specimens obtained before CRT, and the intensities of their expression were tested for correlations with the clinical effects of CRT.RESULTS: The esophageal squamous cell carcinomas with negative p53, positive CDC25B, and negative MT expression were found to be significantly more sensitive to CRT. In addition, p53 positivity and CDC25B positivity respomd well to CRT.CONCLUSION: Esophageal squamous cell carcinomas with negative p53,positive CDC25B, and negative MT expressions respond well to CRT. Even with p53 positivity,if with CDC25B positivity, CRT can be expected.
文摘AIM:To investigate the role of p53 antibodies (p53Abs),metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).METHODS:The study included 30 UC patients,15 without dysplasia (group Ⅱ) and 15 with dysplasia (group Ⅲ),in addition to 15 healthy volunteers (group Ⅰ,control subjects).The enzyme-linked immunosorbent assay technique was used to measure serum p53Abs and MTs,while advanced oxidation protein products (AOPPs),and reduced glutathione (GSH) levels were measured by spectrophotometric method in all subjects.RESULTS:In group Ⅱ and group Ⅲ compared to group Ⅰ,there were significant increases in serum levels of AOPPs (145.94 ± 29.86 μmol/L and 192.21 ± 46.71 μmol/L vs 128.95 ± 3.06 μmol/L,P < 0.002 and P <0.001,respectively),MTs (8.18 ± 0.35 μg/mL and 9.20 ± 0.58 μg/mL vs 6.12 ± 0.25 μg/mL,P < 0.05 and P < 0.05,respectively),and p53Abs (20.19 ± 3.20 U/mL and 34.66 ± 1.34 U/mL vs 9.42 ± 1.64 U/mL,P < 0.001 and P < 0.001,respectively).There were significantly higher levels of AOPPs (P < 0.05) and p53Abs (P < 0.001) in UC patients with dysplasia compared to those without dysplasia,while MTs showed no significant difference between the 2 groups (P > 0.096).In contrast,GSH levels showed a significant decrease in both patients' groups (1.87 ± 0.02 μmol/mL and 1.37 ± 0.09 μmol/mL vs 2.49 ± 0.10 μmol/mL,P < 0.05 and P < 0.05 in groups Ⅱ and Ⅲ,respectively) compared with group Ⅰ,and the levels were significantly lower in group Ⅲ than group Ⅱ (P < 0.05).There was a positive correlation between AOPPs and both MTs (r=0.678,P < 0.001) and p53Abs (r=0.547,P < 0.001),and also between p53Abs and MTs (r=0.739,P < 0.001).There was a negative correlation between AOPPs and GSH (r =-0.385,P < 0.001),and also between GSH and both MTs (r=-0.662,P < 0.001) and p53Abs (r=-0.923,P < 0.001).CONCLUSION:Oxidative stress and oxidative cellular damage play an important role in the pathogenesis of chronic UC and the associated carcinogenetic process.p53Abs levels could help in early detection of dysplasia in these conditions.
文摘Metallothioneins (MTs) were discovered in 1957 by Margoshes and Vallee and identified as low-molecular weight and sulphydryl rich proteins. It is not surprising that most mammalian tissues contain age related basal levels of MTs since they are involved in metalloregulatory processes that include cell growth and multiplication. In an effort to understand the biology of this intriguing tumor, various biomarkers such as oncogenes, p53 tumor suppressor gene, waf 1 protein, proliferating cell nuclear antigen, telomerase, microsatellite markers and cytogenetic changes have been examined. One biomarker which has recently shown to be expressed in various human tumors but still less reported in carcinoma is MT. Immunohistochemical detection of MT proteins in cold acetone-fixed paraffin embedded liver sections was performed by the streptavidin-avidin-biotin immuno- peroxidase complex method.
基金Supported by (in part) the MS McLeod Post-Doctoral Fellowship obtained from the Women’s and Children’s Hospital Foundation (to Tran CD)
文摘AIM: To examine the effect of increasing dietary zinc (Zn) intake and the lack of metallothionein (MT) expression on activity of small intestinal disaccharidases. METHODS: MT-Ⅰ and Ⅱ knockout (MT-/-) and wild-type (MT+/+) female mice at 3.5 wk of age were randomly fed with a diet containing 2 (2 Zn), 15 (15 Zn) or 50 (50 Zn) mg Zn/kg (n = 8/group/genotype) for 5 wk. Small intestinal segments (duodenum, jejunum and ileum) were collected and either fixed in 10% formalin for histological analysis or snap frozen in liquid nitrogen for sucrase, lactase and maltase activity analyses.RESULTS: Plasma Zn was significantly (P < 0.05) lower (33%) in MT-/- compared with MT+/+ mice fed the 2 Zn diet. Villus height and crypt depth were increased by approximately 15% in MT+/+ mice compared with MT-/- mice. Duodenal disaccharidase activities were significantly higher in MT+/+ compared with MT-/- mice particularly in those fed the 2 Zn diet. For the 50 Zn diet, jejunal sucrase and lactase activities were significantly higher in MT-/- (13 313 ± 2314; 4107 ± 364 μmol glucose/well/min/g tissue, respectively) compared with MT+/+ mice (7054 ± 608; 1818 ± 174). Similarly, ileal lactase activities were higher in MT-/- (1480 ± 192) compared with MT+/+ (629 ± 353) mice particularly those fed the 2 Zn diet. CONCLUSION: Increasing dietary Zn has little effect on disaccharidases activity in MT wild-type mice. The presence of MT may enhance morphological and functional development of the gut.
基金Supported by the National Natural Science Foundation of China(No.311720449)the National High Technology Research and Development Program of China(No.2012AA10A401)the Scientific Research Foundation for the Excellent Middle-Aged and Youth Scientists of Shandong Province of China(No.BS2010SW039)
文摘Metallothioneins(MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions.A cadmium metallothionein(EcMT-Cd) cDNA with a 189 bp open reading frame(ORF) that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda.Seventeen cysteines were in the deduced amino acid sequence,and the cysteine(Cys)-rich characteristic was revealed in different metallothioneins in other species.In addition,the deduced amino acid sequence did not contain any aromatic amino acid residues,such as tyrosine(Tyr),tryptophan(Trp),and phenylalanine(Phe).EcMTCd mRNA was expressed in all tested tissues(the ovary,muscle,stomach,and hepatopancreas),and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50μmol/L CuSO4or 2.5μmol/L CdCl2.The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4for 12 h and down-regulated in shrimps exposed to CdCl2for 12 h.After 24 h exposure to both metals,its expression was down-regulated.By contrast,at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdCl2.The transcript of EcMT-Cd was very low or even absent before the zoea stage,and the expression of EcMT-Cd was detected from mysis larvae-I,then its expression began to rise.In conclusion,a cadmium MT exists in E.carinicauda that is expressed in different tissues and during different developmental stages,and responds to the challenge with heavy metal ions,which provides a clue to understanding the function of cadmium MT.
基金Supported by a grant from the Hebei Province Science Foundation (No. 03276117)
文摘Objective: To study the expressions and significations of metallothionein (MT) in cervical squamous cell cancer (CSC), bladder transitional cell cancer (BTC) and breast cancer (BC) of woman. Methods: Immunohistochemical method was used to examine the expresses rate of MT in three types of woman cancer tissue. Results: The expressions rates of MT were 54.35% (29/46) in BTC, 67.05% (59/88) in BC and 57.14% (40/70) in CSC. The positive rate of MT expression was higher in low differentiation group than well differentiation group in BTC and CSC (P < 0.05). Positive of MT in lobular cancer was significance higher than medullary and duct cancers (P < 0.05). Conclusion: The expression of MT is related to differentiation degree, and it is a guidance for clinical choice of chemotherapy project.
