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Biomedical subjects

M Saha

Publications and source records attributed to M Saha.

At least 19 recordsLinked to original sources
PubMed2006

Atypical cutaneous leishmaniasis in two patients receiving low-dose methotrexate.

Cutaneous leishmaniasis is a protozoan disease that has high morbidity. There have been increasing reports of leishmaniasis in patients with an underlying immunosuppressed state. We present two cases of cutaneous leishmaniasis caused by Old World species in patients on methotrexate therapy. We postulate that the T-cell-mediated response to leishmaniasis infection could be modulated by methotrexate and may render an immunosuppressed individual more susceptible to developing clinical disease.

Adult↗
PubMed2005

Interspecific variation in heavy metal body concentrations in biota of Sunderban mangrove wetland, northeast India.

The coastal environment of West Bengal, recognized as the most diversified and productive ecosystem among all the maritime states of India, faces organic pollution from domestic sewage and urban and industrial effluents leading serious impacts on biota. The present paper aims at providing information on concentration level of heavy metals among the tissues of benthic polychaetes, bivalve molluscs and finfishes collected from Sundarban mangrove wetland, northeast coast of India. An overall common trend in bioaccumulation was revealed with the following decreasing order: Zn>Mn>Cu>Cr>Se>Hg with few exceptions. Both species dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs. Variability between closely related species is a reflection of different uptake rates, physiology and impact of environmental factors. The results of this analysis suggest that mollusks can play a significant role in trace metal trophic transfer studies, especially as their representatives are intertidally and subtidally ubiquitous.

Animals↗
PubMed2005

Pyoderma gangrenosum outside the context of inflammatory bowel disease treated successfully with infliximab.

A 63-year-old man with chronic lymphocytic leukaemia developed pyoderma gangrenosum following minor trauma to the leg. He required intensive inpatient management with a multitude of treatments including larval therapy, surgical debridement, ciclosporin, methotrexate, thalidomide, pulsed intravenous methylprednisolone and high-dose intravenous immunoglobulin, clofazamine and high dose oral corticosteroids, none of which were helpful. Treatment complications included steroid-induced diabetes, Cushing's syndrome and perforated peptic ulcer. The pyoderma remained refractory to treatment and continued to extend until he received intravenous infliximab 5 mg/kg at weeks 0, 2 and 6.

Antibodies, Monoclonal↗
PubMed2004

Evaluation of the concentration of HCH, DDT, HCB, PCB and PAH in the sediments along the lower stretch of Hugli estuary, West Bengal, northeast India.

Detailed analyses of persistent organic pollutants (POPs) such as hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloro ethane (DDT) and its metabolites (DDTs), hexachlorobenzene (HCB) and congeners of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the coastal estuarine environment of West Bengal, northeast India allowed the evaluation of the contamination status, distribution and possible pollution sources. HCH, DDT, HCB, PCB and PAH were identified compounds in all the samples, whereas the concentrations of chlorinated pesticides (trans-eptachlorepoxide, dieldrin, endrin, metaoxychlor and mirex) were below the detection limits and were not of great concern. The pesticides did demonstrate markedly different distributions reflecting different agricultural and domestic usage in the region. The range of concentrations of HCH, HCB, DDT and PCBs in the sediments were 0.11-0.40, <0.05-0.98, 0.18-1.93 and 0.18-2.33 ng/g dry wt, respectively. Overall elevated levels of HCB, DDT and PCB were recorded at Babughat, a very closely located site of the metropolitan megacity Calcutta. Fluoranthene (flu) and pyrene (py), the dominant 4-ring PAHs, also showed an abrupt elevated concentrations at Babughat with values of 214 and 144 ng/g dry wt, respectively. Among the isomers and metabolites of HCH, DDT and PCB, alpha-HCH, pp'-DDT and PCB (101), PCB (118), PCB(153) and PCB (138) were found to be dominant. High ratios of metabolites of DDT to SigmaDDTs reveal recent use of DDT in this coastal environment. Fluoranthene, pyrene, 1,2-benzo(a)anthracene and chrysene formed the dominant congeners out of 19 identified PAHs. The sources of contamination are closely related to human activities such as domestic and industrial discharge, automobile exhausts, street runoff, slum sewage, agricultural chemicals and soil erosion due to deforestation as well as atmospheric transport. This study is compared to other coastal and estuarine environments in India and abroad. The baseline data can be used for regular ecological monitoring, considering the industrial and agricultural growth around this important estuarine ecosystem.

Agriculture↗
PubMed2004

Studies on the production and purification of an antimicrobial compound and taxonomy of the producer isolated from the marine environment of the Sundarbans.

A microorganism isolated from the Sundarbans region of the Bay of Bengal, India, showed potent antimicrobial activity against gram-positive and gram-negative bacteria, molds, yeast and several multiple-drug-resistant (MDR) bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The isolate grew in the presence of 20% (w/v) NaCl, antibiotic production being maximum with 5% (w/v) NaCl in the production medium. Natural seawater stimulated antibiotic biosynthesis. The absence of catabolite repression during the synthesis of the antimicrobial substance was demonstrated by the utilization of glucose by this isolate. The 16S rRNA gene of this aerobic, gram-positive, mycelium- and spore-forming microorganism was amplified, and molecular phylogenetic analysis of the DNA sequence showed less than 93% similarity with its closest relative, indicating differentiation at the genus level. The highly stable, active principle was purified by butyl acetate extraction and silica-gel chromatography and a single compound was found to posses the broad-spectrum activity. Molecular characterization showed that the active compound is a lipid. Bioreactor studies demonstrated that antibiotic production is strongly dependent on the scale of operation and there is a definite relation between the dissolved oxygen concentration, medium pH, glucose utilization, cell differentiation and antibiotic production. Maximum production in 30 h could be obtained by regulation of the medium pH in the alkaline range by a combination of controlled addition of NaOH, regulation of the air supply and changes in the reactor configuration. Considering all of the above evidences and based on comparison with the current literature, a novel antimicrobial appears to have been isolated.

Anti-Bacterial Agents↗
PubMed2004

Situs inversus and acute coronary syndrome.

Dextrocardia is a rare clinical phenomenon with a reported incidence of one in 10 000. Consequently, acute coronary syndromes in such patients are rare. When chest pain occurs in this setting, it is important to be aware of the unique problems that may occur if coronary intervention is contemplated. Previous case reports have shown successful attempts at reperfusing one coronary artery percutaneously. In this case, coronary stents were successfully deployed in two vessels of a man with situs inversus, which has not been reported before. Additionally, the angiographic results that followed from successful intervention did not produce the expected haemodynamic and electrocardiographic changes.

Aged↗
PubMed2004

Goblet cell status in idiopathic ulcerative colitis--implication in surveillance program.

Idiopathic ulcerative colitis (IUC) patients have higher incidence of dysplasia and malignancy. Close follow-up with biopsy at regular interval is mandatory. The study was done to correlate incidence of atypical epithelium, goblet cell hyperplasia (GCH) and disease duration (DD) with Ki67, AgNOR and p53 expression in IUC with disease for 5 or more years. Ki67 and AgNOR are good indicators of cellular proliferation and p53 tumour suppressor protein is a marker for neoplastic cell. Of 130 cases studied, 40 cases showed atypical epithelium and were selected for further study. DD in these 40 cases ranged from 60 to 228 months. All had GCH and showed histological features of chronicity. Low-grade dysplasia (LGD) was seen in 15 cases, indefinite for dysplasia (ID) in 8 and inflammatory atypia in 17 cases. Disease duration showed no influence in the type of atypical epithelium. A positive staining of lining epithelium by Ki67 and p53 was not restricted to dysplasia. LGD and ID showed stronger p53 nuclear staining. AgNOR appeared to be a more sensitive marker than Ki67. GCH showed a positive correlation with DD and AgNOR index. p53 expression correlated positively with goblet cell hyperplasia. Conclusion- goblet cell hyperplasia could indicate presence of epithelial cell dysplasia.

Adolescent↗
PubMed2002

Microwave induced diastereoselective synthesis of spiro[indole-oxiranes] and their conversion to spiro[indole-pyrazoles].

The microwave induced diastereoselective synthesis of spiro[3H-indole-3,2'-oxiranes]-3'-benzoyl-2 (1H)-one is reported. Epoxidation of 3-aroylmethylene indole-2-one 1 with alkaline H2O2 under microwave irradiation in an open vessel under controlled conditions yields a diastereomeric pair of spiro[3H-indole-3,2'-oxiranes]-3'-benzoyl-2 (1H) ones 2 and 3 in 65-85% yield. The stereoselectivity depends upon the reaction time and power output. The spiro[indole-pyrazoles] 4 have been synthesised by the reaction of 2 with hydrazine hydrate. Under the same condition 3 gave the mixture of products. All synthesised compounds have been screened in vitro for their antifungal activity against Rhizoctonia solani, Fusarium oxysporum and Collectotrichum capsici and antitubercular activity against Mycobacterium tuberculosis.

Antifungal Agents↗
PubMed2001

Dopamine induced protein damage in mitochondrial-synaptosomal fraction of rat brain.

Dopamine during in vitro oxidation induced covalent cross-linking of membrane proteins in rat brain crude mitochondrial-synaptosomal fraction. The process is not inhibited by hydroxyl radical scavengers, lipid soluble anti-oxidants, metal-chelator or catalase, but reduced glutathione produced a dramatic inhibition of cross-linking. The protein cross-linking mediated by dopamine is not associated with any detectable membrane lipid peroxidation but significant formation of protein bound quinone takes place during incubation. Our results indicate that reactive quinones rather than oxygen free radicals are involved in dopamine induced protein cross-linking in rat brain membrane fraction.

Animals↗
PubMed2001

Transnasal access for sampling a skull base lesion.

SUMMARY: Transnasal needle access for sampling was used in two patients with posterior nasopharyngeal lesions. The procedure was performed under CT guidance. This new technique is simple and appears suitable for selected cases. The two cases and the details of the procedure are described.

Adult↗
PubMed1999

HLA class I allele distributions in six Pacific/Asian populations: evidence of selection at the HLA-A locus.

The distributions of HLA-A alleles in six Pacific/Asian populations, Malay, Papua New Guinea (PNG) Highlands, two Indonesian groups, and two PNG Lowland groups, as well as the distribution of the HLA-B alleles in the PNG Highlands population, were determined using polymerase chain reaction (PCR) immobilized sequence-specific oligonucleotide (SSO) probe typing methods. The allele frequency distributions at the HLA class II loci, DRB1, DQB1 and DPB1 were also determined by PCR/SSO methods in an additional study of the same populations. In most of these populations, the HLA-A*2402 allele was the most frequent, attaining a frequency of 0.78 in the PNG Highlands. A*1101 was the next most frequent allele, followed in frequency by the *3401 allele. The HLA-B*1506, *4001, *5601 and *5602 alleles comprised 73% of the allele diversity at the B-locus in the PNG Highlands. Two previously unreported HLA-A alleles were identified in Indonesians and Malays, based on novel probe reactivity patterns. Cloning and sequencing identified these as A*1104 and *2410. Sequence comparisons show that these new alleles differ at codon 187 from their putative parental alleles (*1101 and *2403) by dinucleotide changes in the first two codon positions. These changes involve a Thr to Arg (CG to AC) and an Arg to Thr substitution (AC to CG) at position 187; residues at this position participate in pocket A of the peptide binding groove. Comparison of the HLA-A allele frequency distributions indicate that Malays are the most diverse (heterozygosity (h)=0.88) and the PNG Highlanders are, by far, the least diverse (h=0.37) of the groups studied. However, the diversity of B-locus alleles in the PNG Highlanders (h=0.91) was greater than that observed at the A-locus of any of the populations reported here. The remarkably high allele frequency of A*2402 in the PNG Highlands could reflect founder effects and population bottlenecks, genetic drift, or positive directional selection. The distribution of the HLA-B locus alleles and class II alleles, as well as mtDNA sequence data in the PNG Highlands indicates a reasonably high level of diversity at other loci, arguing that the high frequency of A*2402 cannot be attributed entirely to founder effects, bottlenecks, or drift and suggests the operation of positive selection for the A*2402 allele in this population.

Alleles↗
PubMed1998

Spectral studies on the interaction of iodine and anthracene sulfonate with bacterial phospholipids from different mutants of Salmonella minnesota.

Using spectrophotometric and spectrofluorometric techniques, the interaction of iodine and 2-anthracene sulfonate (ANS) with the phospholipids (PL) isolated from four genetically correlated Salmonella minnesota isolates viz., a smooth form (S), a deeply rough mutant (Rc) and two intermediate forms (Ra and Rb) were studied. Appearance of an isosbestic point and a new band in absorption spectra indicated charge-transfer (C-T) interaction of iodine with the PL through the formation of 1:1 complex. Stern-Volmer type fluorescence quenching of PL was observed with the addition of iodine to PL, while PL enhanced the fluorescence of anionic dye ANS. The values of the binding constants between iodine/PL and ANS/PL, measured by using suitable equations, showed a systematic gradation in the molecular properties of the PL in the membrane structure in smooth (S) and rough (Ra, Rb and Rc) mutants of Salmonella minnesota.

Anthracenes↗