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Taniguchi N, Kaneto H, Islam KN, Hoshi S, Myint T. Glycation of metal-containing proteins such as Cu,Zn-superoxide dismutase, ceruloplasmin, and ferritin: possible implication for DNA damage in vivo. Contrib Nephrol 2015; 112:18-23. [PMID: 7554989 DOI: 10.1159/000424088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- N Taniguchi
- Department of Biochemistry, Osaka University Medical School, Japan
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Mathur A, Awin N, Adisasmita A, Jayaratne K, Francis S, Sharma S, Myint T. Maternal death review in selected countries of South East Asia Region. BJOG 2014; 121 Suppl 4:67-70. [PMID: 25236636 DOI: 10.1111/1471-0528.13001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2014] [Indexed: 11/27/2022]
Abstract
Understanding the underlying factors that led to maternal deaths through a maternal death review (MDR) throws light on the causes, characteristics and circumstances of the death. We reviewed and report on the implementation of MDR in India, Indonesia, Myanmar, Nepal and Sri Lanka, capturing the experiences of MDR initiatives, follow-up actions and lessons learnet. Overall, while the findings from MDRs have been used to design or change policies and strategies for improvement of services provided, there are still challenges in scaling up these initiatives, particularly in the larger countries.
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Affiliation(s)
- A Mathur
- Department of Family Health and Research, WHO South East Asia Regional Office (SEARO), New Delhi, India
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Rajaram S, Burke K, Connell B, Myint T, Sabaté J. A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. J Nutr 2001; 131:2275-9. [PMID: 11533266 DOI: 10.1093/jn/131.9.2275] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Frequent consumption of nuts is associated with decreased risk of cardiovascular disease. We investigated the effect of pecans rich in monounsaturated fat as an alternative to the Step 1 diet in modifying serum lipids and lipoproteins in men and women with normal to moderately high serum cholesterol. In a single-blind, randomized, controlled, crossover feeding study, we assigned 23 subjects (mean age: 38 y; 9 women, 14 men) to follow two diets, each for 4 wk: a Step I diet and a pecan-enriched diet (accomplished by proportionately reducing all food items in a Step I diet by one fifth for a 20% isoenergetic replacement with pecans). The percentage of energy from fat in the two diets was 28.3 and 39.6%, respectively. Both diets improved the lipid profile; however, the pecan-enriched diet decreased both serum total and LDL cholesterol by 0.32 mmol/L (6.7 and 10.4%, respectively) and triglyceride by 0.14 mmol/L (11.1%) beyond the Step I diet, while increasing HDL cholesterol by 0.06 mmol/L (2.5 mg/dL). Serum apolipoprotein B and lipoprotein(a) decreased by 11.6 and 11.1%, respectively, and apolipoprotein A1 increased by 2.2% when subjects consumed the pecan compared with the Step I diet. These differences were all significant (P < 0.05). A 20% isoenergetic replacement of a Step I diet with pecans favorably altered the serum lipid profile beyond the Step I diet, without increasing body weight. Nuts such as pecans that are rich in monounsaturated fat may therefore be recommended as part of prescribed cholesterol-lowering diet of patients or habitual diet of healthy individuals.
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Affiliation(s)
- S Rajaram
- Department of Nutrition, School of Public Health, Loma Linda University, Loma Linda, California, USA
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Sakata N, Uesugi N, Takebayashi S, Nagai R, Jono T, Horiuchi S, Takeya M, Itabe H, Takano T, Myint T, Taniguchi N. Glycoxidation and lipid peroxidation of low-density lipoprotein can synergistically enhance atherogenesis. Cardiovasc Res 2001; 49:466-75. [PMID: 11164857 DOI: 10.1016/s0008-6363(00)00262-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE The purpose of this study was to clarify the role of glycoxidation and lipid peroxidation of low-density lipoprotein (LDL) in atherogenesis. METHODS AND RESULTS We examined the formation of N(epsilon)-(carboxymethyl) lysine (CML), a glycoxidation product, and malondialdehyde (MDA), a lipid peroxidation product, in vitro and their co-localization in human atherosclerotic lesions. Immunochemical analysis revealed that CML was formed in a time-dependent manner by human LDL incubated with copper ions and glucose, i.e. an in vitro model of glycoxidation of LDL. When LDL was exposed to copper ions alone, a small amount of CML was formed, however this was significantly less in oxidized LDL than glycoxidative LDL. In contrast, MDA formation was observed in both oxidation and glycoxidation of LDL, but not in glycation of LDL. Hexitol-lysine (HL), an Amadori product, was formed by both glycation and glycoxidation of LDL, but not by oxidation of LDL. Immunohistochemical analysis showed that CML and MDA accumulated mainly in macrophage/foam cells, while pyrraline, a non-oxidative product of glycation, and apolipoprotein B were localized in the extracellular matrix in atherosclerotic lesions. Atheromas were positive for CML and MDA, but negative for pyrraline. Macrophage/foam cells in atherosclerotic lesions exhibited co-localization of macrophage scavenger receptor-A with CML and MDA, but not with pyrraline. CONCLUSION Our results suggest that glycoxidation and lipid peroxidation of LDL synergistically promote the development of atherosclerotic lesions through interaction with macrophage scavenger receptor-A.
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Affiliation(s)
- N Sakata
- Department of Pathology, School of Medicine, Fukuoka University, 814-0180, Fukuoka, Japan.
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Myint T, Fraser GE, Lindsted KD, Knutsen SF, Hubbard RW, Bennett HW. Urinary 1-methylhistidine is a marker of meat consumption in Black and in White California Seventh-day Adventists. Am J Epidemiol 2000; 152:752-5. [PMID: 11052553 DOI: 10.1093/aje/152.8.752] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Meat consumption predicts risk of several chronic diseases. The authors validate the accuracy of meat consumption reported by food frequency questionnaires and the mean of eight 24-hour recalls, using urinary methylhistidine excretion, in 55 Black and 71 White Adventist subjects in Los Angeles and San Diego, California, in 1994-1997. 1-Methylhistidine excretion predicts vegetarian status in Black (p = 0.02) and in White (p = 0.005) subjects. Spearman's correlation coefficients between 1-methylhistidine and estimated meat consumption were usually between 0.4 and 0.6 for both food frequency questionnaires and 24-hour recall data. This is despite the chance collection of dietary recalls and urines from omnivores on meatless days.
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Affiliation(s)
- T Myint
- Department of Epidemiology and Biostatistics, Loma Linda University, CA 92350, USA
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Okado-Matsumoto A, Myint T, Fujii J, Taniguchi N. Gain in functions of mutant Cu,Zn-superoxide dismutases as a causative factor in familial amyotrophic lateral sclerosis: less reactive oxidant formation but high spontaneous aggregation and precipitation. Free Radic Res 2000; 33:65-73. [PMID: 10826922 DOI: 10.1080/10715760000300621] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Eight mutant Cu,Zn-superoxide dismutases (SODs) related to familial amyotrophic lateral sclerosis (FALS) were produced in a baculovirus/insect cell expression system and their molecular properties in terms of hydroxyl radical formation and aggregation were compared with the wild-type enzyme. Treatment of the enzymes with Chelex 100 resin decreased Cu contents as well as SOD activities in all mutant Cu,Zn-SODs, indicating that the affinities of the enzymes for copper ion were decreased. Contrary to previous reports, all the mutant Cu,Zn-SODs exhibited less reactive oxidant producing ability in the presence of hydrogen peroxide than the wild-type enzyme. Both SOD activities and their reactive oxidant forming correlated well with the copper ion content of the molecules. In addition, the proteins spontaneously aggregated and were precipitated by simple centrifugation at 12,000g for 20 min in keeping their enzyme activities. Since hyaline inclusions found in FALS patients with SOD1 mutations contained components which were reactive to anti-Cu,Zn-SOD antibody, a primary reaction caused by mutant SOD1 may be attributed to their propensity to form aggregates. Aggregated but still active mutant SOD1 would be expected to mediate the formation of reactive oxygen species and nitrosylation in a more condensed state.
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Affiliation(s)
- A Okado-Matsumoto
- Department of Biochemistry, Osaka University Medical School, Suita, Japan
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Meng J, Sakata N, Takebayashi S, Asano T, Futata T, Nagai R, Ikeda K, Horiuchi S, Myint T, Taniguchi N. Glycoxidation in aortic collagen from STZ-induced diabetic rats and its relevance to vascular damage. Atherosclerosis 1998; 136:355-65. [PMID: 9543107 DOI: 10.1016/s0021-9150(97)00238-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glycoxidation reactions lead to the formation of permanent, irreversible chemical modifications and cross-links in protein, such as the glycoxidation products carboxymethyllysine (CML) and pentosidine. It has been implicated that CML as well as Amadori products play a role in the formation of superoxidative products, such as H2O2 and advanced glycosylation endproducts in trapping LDL. Therefore, a possible relationship between glycoxidation and lipoperoxidation might exist because oxidized lipoprotein, which has been directly linked to atheroma formation, could be produced by the superoxidative products released from the pathway of CML formation. Using a CML-specific monoclonal antibody (6D12) and a specific antiserum against hexitol-lysine (HL), an Amadori product, we studied the relationship between glycoxidation and lipoperoxidation by determining the aortic CML contents with ELISA and the fluorescence levels of lipoperoxidation side products, malondialdehyde (MDA) and hydroxynonenal (HNE) from STZ-induced diabetic rats and age-matched control rats. The immunohistochemical and ultrastructural changes relevant to glycoxidation and lipoperoxidation were also studied. The CML content measured by ELISA in DM rats was significantly higher than that in the control rats at 28 weeks (n = 11, P < 0.01). The levels of MDA-linked and HNE-linked fluorescence in the DM rats increased in a similar way and were significantly higher than the levels in control rats at 28 weeks (n = 11, both P < 0.01 at 28 weeks). The CML contents correlated with the fluorescence levels of both MDA-linked (n = 19, r = 0.638, P < 0.01) and HNE-linked fluorescence (n = 19, r = 0.629, P < 0.01) only in the DM rats, but not in the control rats. Our immunohistochemical study thus demonstrated that CML was initially formed in the aortic media of diabetic rats in the 16th week of diabetes, localized primarily in the extracellular matrix surrounding the aortic smooth muscle cells after HL occurred early in the 2nd week of diabetes. Consequently, a significant increase in the extracellular matrix and decrease in the area of the SMCs were observed in the aortic media in the DM rats by a morphometrical study. The in vivo results of this study provided the first evidence that CML correlated with fluorescence levels of MDA and HNE, and thus suggested the existence of a close relationship between glycoxidation and lipoperoxidation in vivo. This information is thus considered to shed some new light on the etiology of atherogenesis in diabetes.
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Affiliation(s)
- J Meng
- The Second Department of Pathology, Fukuoka University Medical School, Japan
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Abstract
The majority of patients with MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) have an A-->G mutation at nucleotide 3243 in mitochondrial transfer (t)RNA. To date there have only been 10 reported cases of MELAS syndrome in patients with a T-->C mutation at position 3271 of mitochondrial tRNA. Although many of the clinical features are similar between patients with these different mutations, it appears that the age at onset is later for the 3271 mutation. This report provides information from a North American kindred with the 3271 mutation (n = 6 proven; n = 2 probable; n = 3 possible) that adds clinical, physiological, histological, and molecular information to the pool of information on this rare disorder. Many of these features were similar to previous reports of both 3243 and 3271 patients. We conclude that the phenotypic expression of these different mutations are similar, but the age of onset for 3271 patients is later than for 3243 patients.
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Affiliation(s)
- M A Tarnopolsky
- Department of Neurology, McMaster University Medical Center, Hamilton, Ontario, Canada
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Pe T, Myint T, Htut A, Htut T, Myint AA, Aung NN. Envenoming by Chinese krait (Bungarus multicinctus) and banded krait (B. fasciatus) in Myanmar. Trans R Soc Trop Med Hyg 1997; 91:686-8. [PMID: 9509180 DOI: 10.1016/s0035-9203(97)90524-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A retrospective study of 8 cases of envenoming by Chinese krait (Bungarus multicinctus) and one banded krait (B. fasciatus) in southern Myanmar is reported. Chinese krait bite produced minimal local reactions, except in one person bitten on the lip which resulted in local swelling. Onset of neurotoxic symptoms occurred 2.5-6 h after the bite, and the interval between bite and death ranged from 12-30 h. Three deaths were due to respiratory failure. Four mildly envenomed cases recovered spontaneously without assisted ventilation. One severely envenomed patient recovered after 8 d intensive respiratory care. Cobra (Naja kaouthia) antivenom had no value in reversing neurotoxic symptoms. Anticholinesterase injection given to one patient failed to improve neurotoxic symptoms. The bite of banded krait (B. fasciatus) resulted in neurotoxic envenoming within 2 h after the bite, with minimal local reactions. The victim died of respiratory failure 14 h after the bite.
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Affiliation(s)
- T Pe
- Intensive Care Unit, Yangon General Hospital, Myanmar
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Kaneto H, Fujii J, Myint T, Miyazawa N, Islam KN, Kawasaki Y, Suzuki K, Nakamura M, Tatsumi H, Yamasaki Y, Taniguchi N. Reducing sugars trigger oxidative modification and apoptosis in pancreatic beta-cells by provoking oxidative stress through the glycation reaction. Biochem J 1996; 320 ( Pt 3):855-63. [PMID: 9003372 PMCID: PMC1218007 DOI: 10.1042/bj3200855] [Citation(s) in RCA: 180] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Several reducing sugars brought about apoptosis in isolated rat pancreatic islet cells and in the pancreatic beta-cell-derived cell line HIT. This apoptosis was characterized biochemically by inter-nucleosomal DNA cleavage and morphologically by nuclear shrinkage, chromatin condensation and apoptotic body formation. N-Acetyl-L-cysteine, an antioxidant, and aminoguanidine, an inhibitor of the glycation reaction, inhibited this apoptosis. We also showed directly that proteins in beta-cells were actually glycated by using an antibody which can specifically recognize proteins glycated by fructose, but not by glucose. Furthermore, fluorescence-activated cell sorting analysis using dichlorofluorescein diacetate showed that reducing sugars increased intracellular peroxide levels prior to the induction of apoptosis. Levels of carbonyl, an index of oxidative modification, and of malondialdehyde, a lipid peroxidation product, were also increased. Taken together, these results suggest that reducing sugars trigger oxidative modification and apoptosis in pancreatic beta-cells by provoking oxidative stress mainly through the glycation reaction, which may explain the deterioration of beta-cells under conditions of diabetes.
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Affiliation(s)
- H Kaneto
- Department of Biochemistry, Osaka University Medical School, Japan
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Hoshi A, Takahashi M, Fujii J, Myint T, Kaneto H, Suzuki K, Yamasaki Y, Kamada T, Taniguchi N. Glycation and inactivation of sorbitol dehydrogenase in normal and diabetic rats. Biochem J 1996; 318 ( Pt 1):119-23. [PMID: 8761460 PMCID: PMC1217596 DOI: 10.1042/bj3180119] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Sorbitol dehydrogenase (SDH) is involved in the polyol pathway, which plays an important role in the pathogenesis of diabetic complications. We have measured the tissue distributions of SDH mRNA, both the immunoreactive enzyme levels and the enzyme activity. SDH mRNA was especially abundant in liver, kidney and testis. Both the activity and enzyme content are high in liver and kidney but not in testis. The discrepancy between mRNA and immunoreactive enzyme levels and the activity of SDH observed in testis was also seen in livers of streptozotocin-induced diabetic rats. SDH was found to exist in both glycated and non-glycated forms, with larger amounts of the glycated protein in the diabetic liver. Moreover, after incubation of purified enzyme with glucose or fructose, its activity was markedly decreased. These results indicate that glycation causes a decrease in SDH activity in liver under diabetic conditions. The same post-transcriptional event might occur to decrease the activity of SDH in testis in normal animals.
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Affiliation(s)
- A Hoshi
- Department of Biochemistry, Osaka University Medical School, Japan
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Feigenbaum A, Chitayat D, Robinson B, MacGregor D, Myint T, Arbus G, Nowaczyk MJ. The expanding clinical phenotype of the tRNA(Leu(UUR)) A-->G mutation at np 3243 of mitochondrial DNA: diabetic embryopathy associated with mitochondrial cytopathy. Am J Med Genet 1996; 62:404-9. [PMID: 8723072 DOI: 10.1002/(sici)1096-8628(19960424)62:4<404::aid-ajmg14>3.0.co;2-s] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We describe a family which demonstrates and expands the extreme clinical variability now known to be associated with the A-->G transition at nucleotide position 3243 of the mitochondrial DNA. The propositus presented at birth with clinical manifestations consistent with diabetic embryopathy including anal atresia, caudal dysgenesis, and multicystic dysplastic kidneys. His co-twin was normal at birth, but at 3 months of life, presented with intractable seizures later associated with developmental delay. The twins' mother developed diabetes mellitus type I at the age of 20 years and gastrointestinal problems at 22 years. Since age 19 years, the maternal aunt has had recurrent strokes, seizures, mental deterioration and deafness, later diagnosed as MELAS syndrome due to the tRNA(Leu(UUR)) A-->G mutation. A maternal uncle had diabetes mellitus type I, deafness, and normal intellect, and died at 35 years after recurrent strokes. This pedigree expands the known clinical phenotype associated with tRNA(Leu(UUR)) A-->G mutation and raises the possibility that, in some cases, diabetic embryopathy may be due to a mitochondrial cytopathy that affects both the mother's pancreas (and results in diabetes mellitus and the metabolic dysfunction associated with it) and the embryonic/fetal and placental tissues which make the embryo more vulnerable to this insult.
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Affiliation(s)
- A Feigenbaum
- Division of Clinical Genetics, Department of Paediatrics, Hospital for Sick Children, University of Toronto, Ontario, Canada
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Abstract
The registered caseload and prevalence of leprosy have declined in Myanmar from a peak of 86.2 per 10,000 population (95% CI 85.43-86.97) in 1973-77 to 26.82 (95% CI 18.46-35.18) in 1988-92. The new case detection rates have also declined from 7.41 per 10,000 (95% CI 6.3- 8.52) in 1968-72 to 1.96 (95% CI 1.43-2.52) in 1988-92. The increase in the multibacillary proportion of new cases from 11.85% (95% CI 11.84-11.86) in 1968-72 to 40.54% (95% CI 37.2-43.88) in 1988-92 and the decline in proportion of new cases under 14 years of age from 26.81% (95% CI 26.8-26.82) in 1968-72 to 11.22% (95% CI 10.92-11.52), coupled with the finding of declining detection rates among school children and in mass village surveys could mean that the incidence of leprosy may be declining.
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Takata I, Kawamura N, Myint T, Miyazawa N, Suzuki K, Maruyama N, Mino M, Taniguchi N. Glycated Cu,Zn-superoxide dismutase in rat lenses: evidence for the presence of fragmentation in vivo. Biochem Biophys Res Commun 1996; 219:243-8. [PMID: 8619815 DOI: 10.1006/bbrc.1996.0212] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cu,Zn-superoxide dismutase (Cu,Zn-SOD) exists in tissues of rats as both glycated and non-glycated forms when separated by boronate acid column chromatography. Glycated Cu.Zn-SOD is most abundant in rat lenses compared to other tissues. In normal rats lens levels of glycated Cu.Zn-SOD showed a gradual increase with age, whereas in diabetic rats substantial increases were observed. Immunoblotting analyses, using anti-hexitol lysine IgG, indicated that glycated Cu.Zn-SOD contains Amadori products. Moreover, Cu.Zn-SOD in lenses was site-specifically fragmented probably because of glycation. This the first report of a fragmented protein, such as Cu,Zn-SOD, occurring in vivo.
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Affiliation(s)
- I Takata
- Department of Pediatrics, Osaka Medical College, Japan
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Merante F, Myint T, Tein I, Benson L, Robinson B. An additional mitochondrial tRNAIle point mutation (A‐to‐G at nucleotide 4295) causing hypertrophic cardiomyopathy. Hum Mutat 1996. [DOI: 10.1002/(sici)1098-1004(1996)8:3<216::aid-humu4>3.3.co;2-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Fujii J, Myint T, Okado A, Kaneto H, Taniguchi N. Oxidative stress caused by glycation of Cu,Zn-superoxide dismutase and its effects on intracellular components. Nephrol Dial Transplant 1996; 11 Suppl 5:34-40. [PMID: 9044305 DOI: 10.1093/ndt/11.supp5.34] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
It is now evident that the redox state of the cell is a pivotal determinant of the fate of cells. Extensive production of reactive oxygen species (ROI) causes necrotic cell death. Even transient or localized production of ROI may mediate a signal for apoptotic cell death, whereas small amounts of ROI function as an intracellular messenger of some growth stimulants. Accumulating evidence supports the concept that decreases in Cu,Zn-superoxide dismutase (SOD) activity causes apoptotic cell death in neuronal cells. Our data using mutant Cu,Zn-SOD related to familial amyotrophic lateral sclerosis (FALS) suggest that glycation itself and ROI produced from the glycated proteins are involved in many diseases, including diabetic complications. Glycation of important cellular components, including lipid, DNA and proteins, induces dysfunction of these components. Mutant proteins in patients with various hereditary diseases would be destabilized by the glycation reaction, as shown in the case of mutant Cu,Zn-SODs, thereby hyperglycaemic conditions would trigger the onset of some hereditary diseases such as FALS and Alzheimer's disease. Glycation, particularly of antioxidative enzymes, would enhance production of ROI, resulting in oxidative damage to the cells.
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Affiliation(s)
- J Fujii
- Department of Biochemistry, Osaka University Medical School, Japan
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Abstract
A third point mutation in the mitochondrial tRNA(Ile) gene associated with hypertrophic cardiomyopathy and respiratory chain dysfunction in heart is reported. An A-to-G transition at nucleotide position 4295 was shown to be highly evolutionarily conserved, never present in control individuals, and to segregate with the disease. A PCR-based diagnostic test and endomyocardial biopsies were used to detect both the biochemical deficiency and the level of heteroplasmy in heart. The implications of this new mitochondrial DNA point mutation are discussed.
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Affiliation(s)
- F Merante
- Department of Biochemistry, University of Toronto, Ontario, Canada
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Abstract
Bovine ceruloplasmin underwent fragmentation following non-enzymatic glycosylation. Western blot and ELISA analyses indicated that a polyclonal rabbit antiserum to hexitolysine reacted with bovine ceruloplasmin after incubation with 0.1 M glucose. The same fragmentation was seen upon exposure of the protein to a hydrogen peroxide bolus. Both catalase and EDTA blocked peroxide-dependent fragmentation. Incubation with glucose resulted in a time-dependent release of Cu2+. The released Cu2+ appeared to participate in a Fenton-type reaction to produce hydroxyl radicals, which effected the fragmentation. Hydroxyl radical scavengers such as thiourea, mannitol, methionine, and formate inhibited this cleavage. ESR spectral studies also supported participation of hydroxyl radicals. Inhibition by EDTA of the fragmentation induced by an H2O2 bolus also supports a role for copper in a Fenton-type reaction. Taken together these results suggest that reactive oxygen species, such as superoxide anion and H2O2, were formed by the Maillard reaction which led to hydroxyl radicals being produced by a copper-dependent Fenton-type reaction. Both processes are likely to be involved in the fragmentation of ceruloplasmin.
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Affiliation(s)
- K N Islam
- Department of Biochemistry, Osaka University Medical School
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Myint T, Hoshi S, Ookawara T, Miyazawa N, Suzuki K, Taniguchi N. Immunological detection of glycated proteins in normal and streptozotocin-induced diabetic rats using anti hexitol-lysine IgG. Biochim Biophys Acta 1995; 1272:73-9. [PMID: 7548237 DOI: 10.1016/0925-4439(95)00067-e] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A polyclonal antibody specific for the Amadori compound, a product of an early stage of the Maillard reaction, was raised in rabbits by immunization with hexitol-lysine (1-glucitol-lysine or 1-mannitol-lysine) coupled with various carrier proteins. The affinity purified antibody has a high titre and preferentially recognizes the glucose adduct, in the presence of sodium borohydride, as judged on enzyme-linked immunosorbent assay as well as immunoblot analysis. The glycated proteins (Amadori products) in various tissues of normal and streptozotocin-induced diabetic rats were examined by immunoblot analysis. In diabetic conditions, kidney, liver, lens, brain and lung proteins are more susceptible to glycation than other tissue proteins. Heart, spleen, adrenal gland and muscle proteins exhibit similar extents of glycation in both normal and diabetic conditions. This is the first demonstration of a specific antibody against the Amadori compound being raised with a synthetic compound, and of the tissue distribution of glycated proteins in normal and diabetic conditions. The antibody was very useful for in vitro and in vivo experiments on the Maillard reaction.
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Affiliation(s)
- T Myint
- Department of Biochemistry, Osaka University Medical School, Japan
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Smith DR, Elnatan J, Myint T, Goh HS. Association of activated proto-oncogenes ras and myc in colorectal carcinomas. Ann Acad Med Singap 1995; 24:393-8. [PMID: 7574421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have examined 60 colorectal carcinomas for activation of two proto-oncogenes, c-myc and c-Ki-ras. Over-expression of c-myc mRNA as determined by Northern analysis was found in 58% of cases (35/60). Activation of the c-Ki-ras gene by point mutations in codons 12 or 13 as determined by mismatch specific oligonucleotide hybridisation was found in 35% (21/60) of cases. There was a statistically significant association between activation of c-Ki-ras and over-expression of c-myc (P = 0.03), with 76% of tumours with an activated c-Ki-ras proto-oncogene showing over-expression of c-myc. The association was significant in left-sided colorectal tumours (P = 0.03) but not right-sided (P = 0.5). However, whereas only 59% of left side tumours showed at least one of the two changes (ras activation only, or myc activation only or both), 93% of right side tumours showed at least one of the changes (P = 0.01). Twenty-two percent of left side tumours showed both changes compared with 35% of right side tumours, although this result did not achieve significance (P = 0.2). These results suggest that in left-sided colorectal tumours ras and myc cooperate, as established in vitro, to produce neoplastic transformation while different pathway(s) are involved in right-sided tumours.
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Affiliation(s)
- D R Smith
- Department of Colorectal Surgery, Singapore General Hospital
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23
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Fujii J, Myint T, Seo HG, Kayanoki Y, Ikeda Y, Taniguchi N. Characterization of wild-type and amyotrophic lateral sclerosis-related mutant Cu,Zn-superoxide dismutases overproduced in baculovirus-infected insect cells. J Neurochem 1995; 64:1456-61. [PMID: 7891072 DOI: 10.1046/j.1471-4159.1995.64041456.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We describe the use of a baculovirus expression system to overproduce human Cu,Zn-superoxide dismutase (SOD). Spodoptera frugiperda (Sf21) insect cells infected with a baculovirus carrying the Cu,Zn-SOD cDNA synthesized a large amount of Cu,Zn-SOD apoprotein in the conventional medium. The SOD activity of the apoprotein, which was initially very low, increased in a dose-dependent manner when Cu2+ and Zn2+ were added to the medium. Cells grown in media supplemented with Cu2+ alone exhibited nearly maximal SOD activity. SOD activity reached 40% of the maximal level within 2 h after addition of Cu2+ to postinfected cells cultivated for 3 days in the conventional medium, and the activity gradually increased thereafter. The protein produced by the infected cells was purified by a simple procedure involving two chromatographic steps, DE52 ion exchange and ACA54 gel filtration. Identification of the recombinant Cu,Zn-SOD with the human erythrocyte enzyme was confirmed by immunochemical reactivity to anti-human Cu,Zn-SOD antibody and by partial amino acid sequencing of peptides from purified protein (50 amino acid residues in total). We constructed three mutant enzymes, which have been found in familial amyotrophic lateral sclerosis and are overproduced in Sf21 cells, and purified them. Mutant enzymes Gly41Asp, His43Arg, and Gly85Arg exhibited 47, 66, and 99% of wild-type SOD activity, respectively. The availability of this protein will facilitate investigation of the relationship between the structure and function of the mutant enzymes found in familial amyotrophic lateral sclerosis.
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Affiliation(s)
- J Fujii
- Department of Biochemistry, Osaka University Medical School, Japan
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24
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Takahashi M, Lu YB, Myint T, Fujii J, Wada Y, Taniguchi N. In vivo glycation of aldehyde reductase, a major 3-deoxyglucosone reducing enzyme: identification of glycation sites. Biochemistry 1995; 34:1433-8. [PMID: 7827091 DOI: 10.1021/bi00004a038] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have reported that the enzyme which reduces 3-deoxyglucosone (3-DG), a major intermediate and a potent cross-linker in the Maillard reaction, is identical with aldehyde reductase [Takahashi, M., Fujii, J., Teshima, T., Suzuki, K., Shiba, T., & Taniguchi, N. (1993) Gene 127, 249-253]. The enzyme purified from normal rat liver was found to be partially glycated as judged by binding to a boronate column and reactivity to anti-epsilon-hexitol lysine IgG. Sites of in vivo glycation of rat liver aldehyde reductase were identified by sequencing of digested peptides labeled with NaB[3H]4 and by mass spectrometry. The major glycated sites were lysines 67, 84, and 140. The glycated enzyme had low catalytic efficiency (kcat/Km) as compared to the nonglycated form. In streptozotocin-induced diabetic rats, the glycated form was significantly increased in kidneys. Because the enzyme plays a role in detoxifying 3-DG formed through the Maillard reaction in vivo, glycation of aldehyde reductase and reduction of its activity may result in the metabolic imbalance under diabetic conditions.
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Affiliation(s)
- M Takahashi
- Department of Biochemistry, Osaka University Medical School, Japan
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25
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Abstract
Alterations in the c-myc proto-oncogene in colorectal cancer were studied at the level of RNA expression, gene amplification and rearrangements. One hundred cases of colorectal cancer, stratified by Dukes' stage were examined. The level of messenger RNA expression was measured in tumours and matched normal mucosa from the same patient. Between 5 and 400 fold over-expression was found in 66% of tumours. Neither the presence nor the level of over-expression correlated with tumour staging. A significant correlation (P < 0.01) was found between over-expression of c-myc in tumours and the presence of synchronous adenomas elsewhere in the colon. In contrast to other tumours, no rearrangements of the gene were found on Southern analysis of colorectal cancers. Similarly, amplification of the gene was not found in the cancers examined.
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Affiliation(s)
- D R Smith
- Department of Colorectal Surgery, Singapore General Hospital
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26
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Oo KN, Myint T, Nwe YY, Aye T. Vibrio spp. isolated from natural waters of the city of Yangon, Myanmar. J Diarrhoeal Dis Res 1993; 11:105-7. [PMID: 8409281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Virulence properties of the environmental isolate of vibrios from natural waters of Yangon, Myanmar were studied. Vibrio spp. were isolated for identification by the membrane filtration method and cultured on thio-sulphate-bile-sucrose media. No Vibrio cholerae O1 were isolated. V. cholerae non-O1 were the major vibrio species isolated from the samples. None of them were detected for cholera-toxin-like toxin, thermostable direct haemolysin, or heat-stable enterotoxin. Sixty-one isolates gave haemolytic activity; 27 V. cholerae non-O1 and 6 V. fluvialis isolates produced protease.
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27
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Myint T, Htoon MT, Win M, Yin C. Risk factors among defaulters in the urban leprosy control centre of Thaketa Township in the city of Yangon, Myanmar, 1986. LEPROSY REV 1992; 63:345-9. [PMID: 1479874 DOI: 10.5935/0305-7518.19920041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A total of 884 registered cases from the city of Yangon were retrospectively analysed. The defaulter proportion among cases registered for treatment at the Thaketa Health Centre was 34.16%. It was established that patient sex and occupation are not a factor in defaulting. Paucibacillary cases and cases with no disability are more likely to default.
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Affiliation(s)
- T Myint
- Department of Health, Ministry of Health, Myanmar
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28
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Myint T, Htoon MT, Shwe T. Estimation of leprosy prevalence in Bago and Kawa townships using two-stage probability proportionate to size sampling technique. Int J Epidemiol 1992; 21:778-83. [PMID: 1521983 DOI: 10.1093/ije/21.4.778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Two surveys to estimate leprosy prevalence using two-stage probability proportionate to size sampling technique were conducted in Bago and Kawa townships. A total of 3519 and 3739 individuals were examined in each township. The two surveys were finished within 25 (Bago) and 30 (Kawa) working days at a cost of Kyats 10,000 (US $1500) for each survey. The estimated leprosy prevalence obtained in Bago was 9.95 per 1000 population (95% confidence interval (CI): 7.11-12.78) and in Kawa it was 12.04 per 1000 population (95% CI: 8.85-15.22). A total of 30 (Bago) and 34 (Kawa) new leprosy cases were detected in the two surveys. Grade I disability was seen to be 20% in Bago and 18.78% in Kawa, whereas grade II disability was 17.14% in Bago and 15.56% in Kawa.
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Affiliation(s)
- T Myint
- Department of Health, Ministry of Health, Yangon, Myanmar
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29
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Myint T, Thet AT, Htoon MT, Win M. A comparative KAP study of leprosy patients and members of the community in Hlaing and Laung-Lon townships. Indian J Lepr 1992; 64:313-24. [PMID: 1431320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A KAP study was conducted in the peri-urban Hlaing and rural Laung-Lon Townships in Myanmar. It was found that both the leprosy patients as well as community members were still not sure about the cause of leprosy. Social stigma of leprosy encountered by patients needs to be addressed especially in peri-urban areas. It was also found that the patient's understanding of treatment regularity was still very unsatisfactory, for which health education measures needs to be introduced.
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Affiliation(s)
- T Myint
- Leprosy Control Programme, Department of Health, Yangon, Myanmar
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30
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Koo CC, Tong MC, Tan AT, Heng GT, Teo WS, Chua TS, Ong KK, Ng SS, Myint T. Anti-arrhythmic surgery for atrioventricular junctional and atrioventricular re-entrant tachycardia--a report of six cases. Ann Acad Med Singap 1990; 19:67-72. [PMID: 2327727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Since 15th March 1989, six patients with recurrent supraventricular tachycardia (SVT) had antiarrhythmic surgery performed. There were 4 males and 2 females, ages ranged from 23 to 62 years (mean 41 years). Two of these patients with the Wolff Parkinson White (WPW) syndrome also had syncope. Five of these patients had atrioventricular re-entrant tachycardia (AVRT) involving the bypass tracts. Two patients with the WPW syndrome had persistent antegrade conduction, two had intermittent conduction and the last patient had no antegrade conduction via the bypass tract. The bypass tracts were localised at the left free wall in all the five patients. Only one patient had atrioventricular junctional re-entrant tachycardia (AVJRT) of the slow-fast type. The indications for surgery for these patients include failed medical therapy, "dangerous" arrhythmias and patient's preference. All the patients had surgery performed using the endocardial dissection technique on the cardioplegic heart. There were no perioperative mortality and morbidity. All the patients were discharged within 2 weeks. To date, none of the patients had clinical recurrence of SVT and only one patient remained in atrial fibrillation and is on digoxin. In conclusion, antiarrhythmic surgery should be considered for patients with "symptomatic" palpitations as it is curative with a resumption to normal life.
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Affiliation(s)
- C C Koo
- Department of Cardiology, Singapore General Hospital
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Shwe T, Thaung U, Toe M, Mya MM, Myint T. The effect of tetanus toxoid in leprosy patients. Indian J Lepr 1990; 62:104-8. [PMID: 1688345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Since cases of lepra reaction following smallpox vaccination and BCG vaccination had been reported the effect of tetanus immunisation on leprosy patients (whether it may provoke a lepra reaction or not) was studied. Three doses of purified tetanus toxoid (one ml initially, one ml after six weeks and one ml after six months) were given to 357 leprosy patients and 60 patients living in the same environ were followed as controls. The antibody response following immunisation was followed in six lepromatous leprosy patients using toxin antitoxin neutralisation test at the Lf/1000 level in mice and in three of them the antibody titre of leprosy patients rose to satisfactory level. The number of lepra reactions in these patients was monitored for nine months (two months before vaccination, during the six months period of vaccination and one month after the last dose of vaccine). There was no significant rise in the number of patients with reaction following the vaccination.
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Affiliation(s)
- T Shwe
- Department of Medical Research Ministry of Health, Rangoon, Burma
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32
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Aung-Than-Batu, Htun Nyun R, Hlaing N, Tin F, U T, Myint T, Kyi KK. Chloroquine-resistant malaria in Burma. J Trop Med Hyg 1975; 78:186-9. [PMID: 128638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Two field trials to detect chloroquine-resistant malaria were conducted according to WHO recommendations in a malaria free area near Rangoon. Peripheral blood smears were examined for asexual forms of P. falciparum on day one through to day seven, on day 14, 21, and 28 after a standard dose of 1500 mg. of chloroquine base. Haskins test to detect chloroquine in urine was done on all cases and plasma chloroquine levels were measured in some. Out of 105 patients tested RI resistance was detected in 66, RII in 19 and RIII in three. Subsequent trials with other anti-malarial drugs indicated that the chloroquine-resistant P. falciparum were also resistant to one day therapy with pyrimethamine 50 mg. or sulphamethoxypyridazine 1 G given singly; and resistant to one day therapy with combinations of pyrimethamine 50 mg. plus sulphamethoxy pyridazine 1 G, pyrimethamine 13 mg. plus dapsone 100 mg., and trimethoprim 320 mg. plus sulphamethoxazole 1600 mg. All those tested were sensitive to quinine sulphate, 0-6 G given three times a day for 10 days, and were also sensitive to one day therapy with combinations of trimethoprim 500 mg. plus sulphalene 1 G, and pyrimethamine 50 mg. plus sulphamethoxine 1 G. Pyrimethamine 12-5 mg. plus dapsone 100 mg. in weekly doses was shown to be an effective chemoprophylaxis. Quinine was tested on 38 subjects while other drug schedule were tested on six to eight subjects.
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Weir DR, Dimitrov NV, Houser HB, Suhrland LG, Myint T. Serum proteins and blood vitamins in anemia of the chronically ill. Possible role of protein undernutrition. J Chronic Dis 1969; 22:407-19. [PMID: 5370513 DOI: 10.1016/0021-9681(69)90004-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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34
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Houser HB, Myint T, Weir DR. Estimation of red blood cell thiamine concentration from whole blood and serum thiamine by adjustment for hematocrit. Am J Clin Nutr 1967; 20:46-51. [PMID: 6017008 DOI: 10.1093/ajcn/20.1.46] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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35
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Harris LE, Myint T, Biddulph C, Greenwood DA, Binns W, Miner ML, Madsen LL. Effect of Feeding DDT Dusted Alfalfa Hay to Fattening Lambs. J Anim Sci 1951. [DOI: 10.2527/jas1951.103581x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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