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Biomedical subjects

M R Chowdhury

Publications and source records attributed to M R Chowdhury.

17 recordsLinked to original sources
PubMed2004

Novel missense mutation in the coagulation factor IX catalytic domain associated with severe haemophilia B--Factor IXDelhi.

Factor IX is a vitamin K-dependent serine protease, which exists as a zymogen in the blood. On activation to factor IXa, by factor XIa or tissue factor-factor VIIa complex, it forms tenase complex with factor VIIIa, in the presence of Ca2+. This tenase complex enzymatically converts factor X to factor Xa, thereby bringing about the coagulation cascade. Mutations in factor IX gene have been shown to cause haemophilia B, which is inherited as an X-linked recessive disorder. Herein we report a novel missense mutation at the nucleotide position 30829-T > A in the exon 8 of factor IX gene. This transversion leads to the substitution of histidine 236 to glutamine. This resulting abnormal protein has been named factor IXDelhi. Molecular modelling was performed to predict the molecular pathology of this mutation. We predict that this change in the catalytic domain may affect the surface loop that accommodates Ca2+, thereby leading to severe bleeding disorder.

Catalytic Domain↗
PubMed2004

High ear piercing--a dangerous craze.

Ear piercing is a primitive tradition among the human being. It reflects the culture of many religions, tribes, and communities, predominately adopted by the females. We reported a sixteen years old girl with painful swelling of both pinnas for last one month following piercing the pinna. She was treated locally by general practitioner without significant improvement. On examination frank abscess were detected in both pinna. Under general anesthesia incision drainage and deep curettage was done. She was treated with ciprofloxacin 750 mg 12 hourly for 2 weeks and recovery was uneventful. After one month she developed unsightly cauliflower ear. With this report we want to sensitize our community regards the risk of transmission of needle prick diseases and deformity of pinna following ear piercing

Abscess↗
PubMed2003

Prenatal diagnosis in hemophilia A using factor VIII gene polymorphism--Indian experience.

The heterogeneous nature of the mutations, the size, and the complexity of the factor VIII gene makes direct mutation analysis in hemophilia A families in India an option that is not very feasible and practical. Thus, carrier screening and prenatal diagnosis of hemophilia A often depends on haplotype analysis using restriction fragment length polymorphisms (RFLP) and short tandem repeat (STR) markers to track the defective factor VIII gene within a family. The main objective of this present study was to assess the utility of using polymerase chain reaction (PCR)-based five polymorphic markers: four intragenic Hind III, Bcl I, intron 13, and intron 22 STRs and one extragenic marker St14 in prenatal diagnosis. Forty-one chorionic villus samples (CVS) were studied from 41 families with a history of hemophilia A. PCR and RFLP were used for screening. Intron 22 STR showed the highest informativeness (60.9%), followed by Hind III (51.2%), Bcl I (46.3%), & intron 13 STR (51.2%); the extragenic marker St14 (VNTR) was informative in 46.3% of families. Linkage analysis, with the combined use of these five PCR-based polymorphic markers, gives good informativeness of 87.8% in the Indian population. Of the 41 CVS tested, 21 were found to be male fetuses and of these 13 were found likely to be affected with hemophilia A. Only in 12.2% of the families were none of the markers informative.

Chorionic Villi↗
PubMed2003

Association of cucumovirus and potyvirus with betelvine (Piper betle L.) as evidenced by ELISA and RT-PCR.

An attempt was made to detect various viruses of Piper betle grown at Mahoba and Banthara in India. DAC-ELISA and RT-PCR tests were performed in leaf sap samples of betelvine for detection of a cucumovirus (Cucumber mosaic virus) and potyvirus (Bean yellow mosaic virus) using specific antibodies and universal primers of respective viruses. DAC-ELISA could detect only CMV. However, RT-PCR detected both cucumovirus and potyvirus infection in betelvine samples. Association of CMV with betelvine was observed for the first time in the present study.

Antibodies, Viral↗
PubMed2001

Factor IX gene polymorphisms in Indian population.

Hemophilia B is an X-linked, recessive disorder of hemostasis, caused by a defect in coagulation factor IX. To date, several restriction fragment length polymorphisms (RFLPs) have been identified within the gene for human factor IX. The incidence of these RFLPs differs significantly in different populations. In the present study, we analyzed the heterozygosity frequency and the allele frequency of three common intra- and extragenic polymorphic sites of the factor IX gene in Indian population. The main objective was to test the informativeness of two intragenic markers Dde I and Xmn I and one extragenic marker Hha I for carrier detection and prenatal diagnosis. The method used was polymerase chain reaction (PCR) and RFLP, which is economical yet simple to perform. In Indian population Dde I marker showed an informativeness of 69.0% followed by 38.0% for Hha I and 23.0% for Xmn I. The cumulative informativeness of these three markers was found to be 80 to 82%. A comparison of the heterozygosity rates of these three markers with the other ethnic groups showed that Indian population had almost similar pattern with the Caucasians and American blacks but differed significantly from the Orientals including Japanese, Chinese and Malays.

Deoxyribonucleases, Type II Site-Specific↗
PubMed2000

Factor VIII gene polymorphisms in the Asian Indian population.

Little is known about the heterozygous frequency of factor VIII gene markers in the Asian Indian population. The objective of this study was to establish the heterozygous frequency of polymorphic markers within and flanking the factor VIII gene in Indians and identify those most informative for carrier screening and prenatal diagnosis. Factor VIII gene polymorphism analysis at intragenic and extragenic sites was carried out by the polymerase chain reaction (PCR) method and Southern blot procedure. Sixty-three Asian Indian haemophiliacs and their families were screened. A control group of 150 women from nonhaemophilic families were screened for two markers, HindIII and BclI. Among the intragenic markers studied, the HindIII restriction fragment length polymorphism (RFLP) showed the highest heterozygous frequency (0.52) followed by the intron 13 (0.47) and intron 22 (0. 44) short tandem repeats (STRs). Among extragenic markers, TaqI had the highest heterozygous frequency (0.75) followed by BglII (0.54). The intron 22 inversion mutation was observed in eight (40%) of 20 severe cases. In the population studied the most diagnostic polymorphisms were the intragenic markers, intron 22 (70%) STR followed by the intron 13 (52%) STR and HindIII (52%) RFLP, and the TaqI (50%) extragenic marker. Application of HindIII, BclI and the intron 22 dinucleotide repeat combined were diagnostic in 87.2% of haemophilia A families studied.

Alleles↗
PubMed2000

Recent advances in chromosome breakage syndromes and their diagnosis.

Chromosome instability is a characteristic cytogenetic feature of a number of genetically determined disorders collectively called as the chromosome breakage syndromes or DNA-repair disorders. They are characterized by susceptibility to chromosomal breakages, increased frequency of breaks and interchanges occurring either spontaneously or following exposure to various DNA-damaging agents. These diseases are a group of genetic disorders sharing a number of features. They are all autosomal recessive, show an increased tendency for chromosomal aberrations and to develop malignancies. The principal diseases in this group having a diverse etiology and clinical manifestations include Fanconi anemia (FA), ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), Bloom syndrome (BS), xeroderma pigementosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD). The underlying defect in these syndromes is the inability to repair a particular type of DNA damage. A number of repair disorder phenotypes are caused by more than one gene. The diagnosis of these syndromes is made by the characteristic clinical features specific to each disease, but the definitive diagnosis is achieved by laboratory investigations such as cytogenetic, biochemical and molecular methods. The importance of prenatal diagnosis and our experience are discussed in this article.

Ataxia Telangiectasia↗
PubMed1999

An update on the prevalence of HIV/AIDS in Bangladesh.

The National AIDS Committee was formed in 1985 to develop and support policies that prevent transmission of human immunodeficiency virus (HIV). In 1990, the Institute of Epidemiology, Disease Control and Research in the Ministry of Health began sero-surveillance for AIDS/HIV infection. Convenience sampling was conducted among prisoners, sailors, truckers, antenatal attendees, repatriated Bangladeshi workers, and brothel-based prostitutes in Dhaka. In 1994, commercial sex workers in other high-risk areas were included in surveillance activities. Among over 75,700 HIV tests through 1998, 119 have been confirmed positive for HIV. While the cumulative HIV prevalence rate was only 1.5/1,000 tests, it was significantly higher among men (p < 0.0001) than among women. The rates among men were as high as 28/1,000 tests in 1996 and 21/1,000 tests in 1997. Almost 50% of the reported HIV cases are from cities on the border of India and Myanmar. It is anticipated that HIV transmission will increase further given the high prevalence of risk behaviors, core high-risk groups, and extreme poverty.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Utility of XY-amelogenin gene primers for detection of sex chromosomes.

The utility of polymerase chain reaction (PCR) amplification of amelogenin gene as a reliable and rapid means of determination of sex chromosomes was tested in 20 patients of X-linked disorders (Duchenne muscular dystrophy, haemophilia and Wiscott-Aldrich and Hunter's syndromes), 12 of intersex (testicular feminization syndrome, male pseudohermaphrodites, true hermaphrodites) and 21 of congenital adrenal hyperplasia. Of these, 26 (49%) cases were for prenatal diagnosis of X-linked diseases and congenital adrenal hyperplasia (CAH). The presence of X and Y chromosomes was determined within 24 h of receiving the samples. The results were in conformity with cytogenetic studies in all instances. The analysis of amelogenin gene proved helpful in the diagnosis and management of these patients.

Adolescent↗
PubMed1996

Improved method for study of chromosomes of chorionic villus samples.

Chorionic villus sampling (CVS) offers rapid prenatal diagnosis of chromosomal disorders. We evaluated four methods for chromosomal analysis of chorionic villi (three based on direct preparations and one on long-term culture) in order to define a method which would provide good quality metaphases in sufficient numbers. The direct culturing method using synchronisation and dissociation with dispase was as good as long-term culturing. The optimal period of gestation for study was 10-12 wk.

Chorionic Villi Sampling↗
PubMed1996

Cytogenetic studies in ataxia telangiectasia & their use in prenatal diagnosis.

Cytogenetic studies were carried out in obligate ataxia telangiectasia (AT) heterozygotes, AT homozygotes and control subjects. Rate of chromosomal aberrations and the frequency of micronuclei were examined before and after radiation (100 rads). Significant differences in the rate of chromosomal aberrations and micronuclei were observed among heterozygotes, homozygotes and controls. The same methods were then applied for prenatal diagnosis of AT using amniotic cell culture in two families.

Ataxia Telangiectasia↗
PubMed1993

Effects of endothelin on fluid and NaCl absorption across the jejunum in anesthetized dogs.

The aim of the present study was to investigate the effects of endothelin (ET) on fluid and NaCl absorption across the jejunum. Dogs were anesthetized with pentobarbital sodium (30 mg/kg i.v.). Polyethylene catheters were placed in the superior mesenteric arteries and portal vein for infusions and to measure arterial and portal venous pressure. Superior mesenteric arterial blood flow was continuously measured with an ultrasonic flow probe. A 30-cm-long jejunal loop was made at 10 cm from the duodenal fossa. Infusion of saline, ET-1, ET-3, or phenylephrine (PE) was initiated 10 min before pouring the test solution into the jejunal loop and continued for 25 min. The net fluid (7.2 +/- 0.9 ml, mean +/- SE, n = 8), Na+ (1.1 +/- 0.1 mEq), and Cl- (1.1 +/- 0.2 mEq) absorption during saline infusion was not significantly different from those (7.0 +/- 1.0 ml, 1.1 +/- 0.1 mEq, and 1.1 +/- 0.2 mEq) during ET-1 infusion but was significantly decreased to 4.8 +/- 0.6 ml, 0.7 +/- 0.1 mEq, and 0.7 +/- 0.1 mEq by ET-3 infusion. ET-1 increased the mesenteric vascular resistance by 84.7 +/- 23.4% and ET-3 by 64.3 +/- 7.5%. To study the underlying mechanisms, the absorption experiment was performed after the increase in vascular resistance and administration of nitric oxide (NO) synthase inhibitor. We increased the resistance by 127.8 +/- 12.6% with PE and found no effect. Pretreatment with NO synthase inhibitor did not influence the decreased absorption induced by ET-3. In conclusion, ET-3 suppresses jejunal absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1993

Effects of endothelins on fluid and NaCl absorption across the jejunum anesthetized dogs.

The aim of this study was to investigate the effects of endothelins on fluid the NaCl absorption across the jejunum, the jejunal fluid and NaCl absorption and mesenteric hemodynamics in jejunal loops in anesthetized dogs during infusion of saline, endothelin-1 or endothelin-3 into the superior mesenteric artery. Infusion of endothelin-3 decreased the net fluid, Na+, and Cl- absorption; however, saline and endothelin-1 had no effect. To investigate the role of nitric oxide and soluble guanylate cyclase activation in the mechanisms underlying endothelin-3-induced decrease in fluid and electrolyte absorption, measurements were obtained in the presence of the nitric oxide synthesis inhibitor, nitro-L-arginine methyl ester (L-NAME) or the soluble guanylate cyclase inhibitor, methylene blue. The endothelin-3-induced decrease in absorption was not influenced by the pretreatment with inhibitors. These results suggest that the endothelin-3 response was not mediated by nitric oxide or soluble guanylate cyclase.

Amino Acid Oxidoreductases↗
PubMed1977

Requirement of chain initiation factor 3 and ribosomal protein S1 in translation of synthetic and natural messenger RNA.

Amino acid incorporation directed by poly(A), poly(U) or R17 RNA has been examined in S1-depleted protein synthesizing systems. We observe that the translation of either synthetic or natural messenger RNA is strictly dependent on the presence of chain initiation factor 3 and ribosomal protein S1. With poly(A) or poly(U) both IF-3 and S1 stimulate amino acid incorporation at least 25-fold, and with R17 RNA the stimulation is approximately 15-fold. More than one copy of S1 per ribosome decreases amino acid incorporation directed by poly(U) or R17 RNA. Initiation complex formation with R17 RNA is also stimulated optimally by the addition of one copy of S1 per ribosome. The function of IF-3 and S1 in protein synthesis is considered.

Bacterial Proteins↗
PubMed1977

Preparation of anti-human globulin serum in Bangladeshi rabbits and goats.

Anti-human globulin was produced in local rabbits and goats by using human O serum mixed with Freund's adjuvants (complete or incomplete) for immunising the animals. A titre of 1/1024 was obtained in rabbit and a titre of 1/8192 was obtained in goat. Quality-and quantity-wise, goat's serum appeared to be better than rabbit's serum.

Animals↗