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Biomedical subjects

D K Mukhopadhyay

Publications and source records attributed to D K Mukhopadhyay.

13 recordsLinked to original sources
PubMed2000

Antitumor activity of methanolic extract of Cassia fistula L. seed against Ehrlich ascites carcinoma.

Effects of methanolic extract (ME) of Cassia fistula seed on the growth of Ehrlich ascites carcinoma (EAC) and on the life span of tumor bearing mice were studied. ME treatment showed an increase of life span, and a decrease in the tumor volume and viable tumor cell count in the EAC tumor hosts. Cytological studies have revealed a reduction in the mitotic activity, and the appearance of membrane blebbing and intracytoplasmic vacuoles in the treated tumor cells. Improvement in the hematological parameters following ME treatment, like hemoglobin content, red blood cell count and bone marrow cell count of the tumor bearing mice have also been observed. The results of the present study suggest that ME of C. fistula seed has an antitumor activity.

Animals↗
PubMed1999

Molecular mechanics aided design of antineoplastic agents from ruthenium coordinate complexes.

Through energy minimization using molecular mechanics force field four ruthenium cordinate complexes have been synthesized. Compound I to IV showed antineoplastic activity with varying degree on EAC bearing mice. Mode of action may be through inhibition of antioxidant property of tumor cell as evident from lipid peroxidase activity. Among the complexes Bis pyridine tetrachloro ruthenium exhibits highest order of activity with respect to increase mean survival time, inhibition of tumour volume, total blood count, hemoglobin and lipid peroxidase activity.

Animals↗
PubMed1998

Long-term, near-total liver replacement by transplantation of isolated hepatocytes in rats treated with retrorsine.

Genetically marked hepatocytes from dipeptidyl peptidase (DPP) IV+ Fischer 344 rats were transplanted into the liver of DPPIV- mutant Fischer 344 rats after a combined treatment with retrorsine, a pyrrolizidine alkaloid that blocks the hepatocyte cell cycle, and two-thirds partial hepatectomy. In female rats, clusters of proliferated DPPIV+ hepatocytes containing 20 to 50 cells/cluster, mostly derived from single transplanted cells, were evident at 2 weeks, increasing in size to hundreds of cells per cluster at 1 month and 1000 to several thousand cells per cluster at 2 months, representing 40 to 60% of total hepatocyte mass. This level of hepatocyte replacement remained constant for up to 1 year, the duration of experiments conducted. In male rats, liver replacement occurred more rapidly and was more extensive, with transplanted hepatocytes representing 10 to 15% of hepatocyte mass at 2 weeks, 40 to 50% at 1 month, 90 to 95% at 2 months, 98% at 4 months, and 99% at 9 months. Transplanted hepatocytes were integrated into the parenchymal plates, exhibited unique hepatic biochemical functions, and fully reconstituted a normal hepatic lobular structure. The extensive proliferation of transplanted cells in this setting of persistent inhibition of resident hepatocytes represents a new general model to study basic aspects of liver repopulation with potential applications in chronic liver disease and ex vivo gene therapy.

Adenosine Triphosphatases↗
PubMed1997

Effect of mycotoxins isolated from Penicillium nigricans on glucose-6-phosphate dehydrogenase.

A new mycotoxin product (NMP) was isolated from the culture of mutated wild strain of P. nigricans which is less toxic and has sterol derivative. NMP (LD50 > 1 g/kg) showed antimicrobial and antineoplastic activities and does not affect the hematological parameters like RBC count and hemoglobin. It maintained normal blood glucose level by increasing the enzyme activity of glucose-6-phosphate dehydrogenase (EC-1.1.1.49; G-6-PDH) by 30%. It also maintained the normal ion balance in the blood of mice. NMP decreased Km value of glucose-6-phosphate dehydrogenase and thus increased substrate affinity of the enzyme. Reduction of toxicity of NMP has been well explained by higher activity of G-6-PDH which is highly specific for production of NADPH.

Animals↗
PubMed1992

A study of Helicobacter pylori in north Indian subjects with non-ulcer dyspepsia.

A prospective case control study was conducted in 50 patients with non-ulcer dyspepsia (NUD) and 10 age and sex matched controls to determine the prevalence of Helicobacter pylori in patients with NUD and to correlate symptoms, histology and presence of H pylori in gastric biopsies. Endoscopic biopsies from antrum and fundus were subjected to urease test and histological examination. On histology, H pylori was identified in 27 (54%) NUD patients and in one of 10 controls. Urease test was positive in 31 (62%) antral and 21 (42%) fundal biopsies in patients with NUD and in only one (10%) of 10 antral biopsies in the control group. On histology, gastritis was present in the antrum in 46 (92%) NUD patients and in the fundus in 40 (80%) cases; of these, 27 (54%) and 15 (30%) had H pylori in antral and fundal biopsies respectively. The severity of antral gastritis correlated with the density of H pylori (p < 0.05).

Adolescent↗
PubMed1983

Ribosomal RNA genes of Neurospora crassa: multiple copies and specificities.

Ribosomal RNA genes were isolated from the germinated conidial and mycelial cells of N. crassa by repeated cycles of 3H-DNA:rRNA reactions followed by hydroxyapatite chromatography. Specificity of multiple copies of those rDNAs with respect to N. crassa cell types was studied. The fraction of N. crassa germinated conidial in vitro labelled 3H-DNA recovered in the presence of rRNA isolated from the same cell type was about 2.2%, when compared with approximately 1.2% rDNAs obtained in mycelial cells. These isolated rDNAs reacted specifically to 26S and 17S rRNAs of eukaryotic (N. crassa) organisms and did not react with 4S tRNAs. rRNA:rDNA reassociation kinetics studies indicate that 90% of the rRNA genes were homogeneous and not identical with the other 10% rRNA genes isolated from N. crassa mycelia. These studies suggest that the possible heterogeneity of rDNA sequences of N. crassa cannot be attributed to inclusion of any tDNA sequences as has been shown in the heterogeneity of rDNA sequences of the bacterium Escherichia coli. The heterogeneity of multiple copies of N. crassa rDNAs could be due to differences in internal or external spacer regions of N. crassa rRNA genes.

Gene Amplification↗
PubMed1980

RNase-sensitive DNA polymerase activity in cell fractions and mutants of Neurospora crassa.

RNase-sensitive DNA polymerase activity (RSDP) was tested in different cell fractions of Neurospora crassa cell types and its morphological mutants. This RSDP was found localized in the microsomal pellet fraction and absent in the purified nuclear pellets isolated from different N. crassa cell types: conidia, germinated conidia, and mycelia. This enzyme is capable of synthesizing a DNA product only in the presence of all four deoxyribonucleoside-5' - triphosphates and Mg2+. Removal of RNA from the pellet fraction by RNase strongly inhibited the DNA synthesis. The endogenous synthesis of DNA in the microsomal pellet fraction was associated with the formation of an RNA:DNA hybrid as analyzed by Cs2SO4 equilibrium density gradient centrifugation. The DNA product after alkali hydrolysis hybridizes with the RNA isolated from the same pellet fraction, as analyzed by elution from hydroxylapatite column at 60C. This DNa product did not hybridize with poly (A). A few mutants tested showed this RNase-sensitive DNA polymerase activity.

Cell Compartmentation↗
PubMedDate not supplied

Endoscopic ultrasonographic evaluation of the rectum in cirrhotic portal hypertension.

Rectal endoscopic ultrasonography was performed using an ultrasound fiberscope in 20 patients with cirrhotic portal hypertension (6 alcoholic patients, 4 patients with hepatitis B surface antigen positive, and 10 cryptogenic patients) and in 10 patients with irritable bowel syndrome as controls. Rectal varices were diagnosed endoscopically when either tortuous or saccular distended veins were seen beneath the mucosa. At rectal endoscopic ultrasonography rectal varices were seen as rounded or oval echo-free structures in the submucosa. Rectal endoscopic ultrasonography also showed perirectal veins outside the rectal wall. Rectal varices were detected by endoscopy in 9 patients and by rectal endoscopic ultrasonography in 17 patients. Rectal endoscopic ultrasonography also detected submucosal veins in 3 of 10 controls. The number and size of submucosal veins seen on rectal endoscopic ultrasonography in patients with portal hypertension were greater than in controls (p < 0.01 for both number and size). The size of perirectal veins was greater in patients than in controls (p < 0.05), although their number was no different (p = NS). A perforating vein communicating between a submucosal and perirectal vein was seen in only one patient. Rectal wall thickness was not different in patients and controls (p = NS). Rectal endoscopic ultrasonography was superior to endoscopy in detecting the presence (85% versus 45%, p < 0.01), and number (p < 0.01) of rectal varices. Our study suggests that rectal endoscopic ultrasonography is useful in detecting changes in rectal and perirectal vasculature in patients with cirrhotic portal hypertension.

Adult↗