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Biomedical subjects

S K Majumder

Publications and source records attributed to S K Majumder.

At least 19 recordsLinked to original sources
PubMed1997

Breast cancer diagnosis using N2 laser excited autofluorescence spectroscopy.

BACKGROUND AND OBJECTIVE: This article reports results of an in vitro study involving 63 patients for the evaluation of the diagnostic potential of N2 laser excited autofluorescence spectroscopy of human breast tissues. MATERIALS AND METHODS: The N2 laser-excited spectra were recorded from benign (fibroadenomas, 35 patients), cancerous (ductal carcinomas, 28 patients), and normal (the uninvolved areas of the resected cancerous specimens). A stepwise multivariate linear regression (MVLR) analysis was developed to analyze the diagnostic content of the breast tissue fluorescence spectra. RESULTS: Significant changes were observed in the autofluorescence from normal, benign, and cancerous breast tissues, particularly in the spectrally integrated fluorescence intensity. The ratio of mean spectrally integrated intensity from cancerous tissues to that from benign tumor and normal tissues were 3.2 and 2.8, respectively. A discrimination parameter based on spectrally integrated intensity alone provided a sensitivity and specificity of up to 99.6% over the sample size investigated for discrimination of cancerous breast tissues from benign/normal. CONCLUSION: Our results suggest that a straightforward measurement of the total integrated fluorescence intensity can provide excellent discrimination between cancerous and benign/ normal breast tissues.

Breast Neoplasms↗
PubMed1995

In vitro activities of PS-15, a new dihydrofolate reductase inhibitor, and its cyclic metabolite against Mycobacterium avium complex.

PS-15, a new dihydrofolate reductase inhibitor, and its cyclic metabolite were evaluated for in vitro activity against 31 clinical Mycobacterium avium complex isolates. Broth dilution MICs of PS-15 ranged from 16 to 64 micrograms/ml. The cyclic metabolite was three to five times more active than the parent compound. Further evaluation of these compounds in an M. avium-infected murine test system will be of interest.

Antimalarials↗
PubMed1992

Remote sensing system to study rodent behaviour.

The instrumental system assembled consists of video monitors which projects signals from remotely placed video camera in the rat pen with pan and tilt arrangement and all operations are done through control-room. Signals obtained from the camera will pass through the monitor and then fed into VCR system which records the behavioural events. Studies carried out with the above system has revealed that all the characteristic behaviour of gerbils (Meriones hurricane Jerdon) which is significantly superior (P < 0.001) over the direct observation method. The integrated sensing system is an ideal instrumental set up for viewing and recording the behaviour of rodents as well as other animals in the experimental pen throughout the year under varying weather and light conditions.

Animals↗
PubMed1989

Cytotoxicity of certain organic solvents and organophosphorus insecticides to the ciliated protozoan Paramecium caudatum.

Responses of Paramecium caudatum, a ciliated protozoan, to acute exposures of certain organic solvents and organophosphorus insecticides (OPI) were studied by determining their lethal concentration (10 min-LC100) and median lethal concentration (4 h-LC50). The solvents and OPI evoked a distinct sequence of responses. Among the five solvents tested, acetone proved most toxic [LC-2.9% and LC50-0.68% (v/v)], while dimethyl sulphoxide (DMSO) showed least toxicity [LC-11.0% and LC50-3.16% (v/v)]. The order of toxicity of solvents was: acetone greater than ethanol greater than methanol greater than N, N-dimethylformamide greater than dimethylsulphoxide. The LC values of six OPI dissolved in either acetone or DMSO indicated that they were more toxic when dissolved in acetone and least toxic in DMSO. Among the OPI, bromophos proved most toxic (LC-10 ppm) while malathion showed least toxicity (LC-200 ppm) in DMSO. The order of toxicity of OPI was: bromophos greater than pirimiphos-methyl greater than parathion methyl greater than dichlorvos greater than fenitrothion greater than malathion. The 4 h-LC50 values computed for bromophos and malathion (dissolved in DMSO) were 575 ppb and 19.9 ppm, respectively, indicating the high susceptibility of P. caudatum to bromophos. The results indicate that the Paramecium toxicity assay could be used as a complementary system to rapidly elucidate the cytotoxic potential of compounds.

Animals↗
PubMed1986

Serum hexachlorocyclohexane residues in workers engaged at a HCH manufacturing plant.

The accumulation of hexachlorocyclohexane, one of the most commonly used chlorinated insecticides, was studied in a high-risk group of people who are exposed during its manufacturing process. The serum HCH concentration was estimated by quantitating its alpha, beta, gamma and delta-isomers with the help of GLC analysis. Exposed workers involved in maintenance work were found to have 3 times higher HCH residues than the controls, while in the plant operators and supervisors the levels were 5 times higher. The most severely exposed were the handlers who are in direct contact with the insecticide. The level of serum HCH residues in them was found to be about 12 times higher than those in the controls. The percentage composition of the insecticide, with respect to the different isomers, varied up to 20% for the gamma-isomer, up to 30% for alpha-isomer and had between 60%-100% of the beta-isomer in the samples. The serum levels of the insecticides were clearly related to the workers' job-related close contact, intensity, frequency, and the duration of their exposure. The total of HCH residues in the sera studied were in the range of 0.143-1.152 ppm. The importance of these findings and the relevant protective measures are discussed.

Chemical Industry↗
PubMed1983

Insecticide fingerprinting technique for detection and location of organochlorine insecticide residues in foods.

Insecticide fingerprinting technique enables the detection and location of DDT and HCH residues in vegetables through the development of green and prussian blue colors respectively. Cut vegetables are pressed against o-tolidine impregnated paper and exposed to sunlight where colored spots appear instantly. The studies on 18 vegetable varieties revealed the pesticide residues and their distribution in different tissues. This direct method is sensitive (0.3/micrograms for HCH & 0.5/micrograms for DDT) and has special applications in quality control laboratories and food industry.

DDT↗
PubMed1983

Testicular atrophy in Gallus domesticus fed acute doses of copper fungicides.

Acute oral toxicity of the copper fungicides, copper sulphate and copper oxychloride, were studied in male Gallus domesticus. The median lethal dose for copper sulphate and copper oxychloride determined were 693 and 1263 mg/kg body weight, respectively. Severe diarrhea and delayed mortality (3 to 6 days) was characteristic of copper oxychloride. Liver weights were nearly doubled in birds fed copper oxychloride and marked dose-dependent testicular atrophy was noticed in both copper sulphate and copper oxychloride fed birds. Mild to severe spermatogenetic arrest concomitant with testicular atrophy was observed. Histochemically, the interstitial (Leydig) cells and seminiferous tubules showed intense accumulation of cholesterol-positive lipids. The degree of lipophilia appeared to be directly proportional to the extent of spermatogenetic arrest, and these results are suggestive of steroidogenic inhibition in the Leydig cells of the atrophied testis.

Animals↗
PubMed1982

Mammalian toxicity of Technical X-factor I. An acute oral study.

Intragastric administration of acute doses of Technical X-factor (beta-isomer free BHC, a byproduct obtained during separation of Lindane from Tech. BHC) carried in peanut oil elicited typical signs of central nervous system depression in adult rats. The computed oral LD50 values of X-factor were 4174 and 5673 mg/kg. body weight for male and female rats respectively indicating that its acute toxicity was of relatively low order compared to Tech. BHC. It is suggested that the low acute mammalian toxicity of X-factor could possibly be due to a direct antagonism of the delta isomer (present in larger proportion in X-factor) with the gamma isomer.

Animals↗
PubMed1981

Interconversions and toxicity changes in hexachlorocyclohexane isomers on dispersion in water.

Studies on the transformations of hexachlorocyclohexane isomers, alpha-, beta-, gamma- and delta-, in aqueous solution were carried out at 25 +/- 1 degree C over a period of four weeks. Gas liquid chromatographic technique was used for analysis. The results indicated a loss as well as interconversion of all the four isomers with time. The resulting changes in toxicity of the aqueous solution were studied against Drosophila using topical application. Toxicity studies with aqueous solution of technical hexachlorocyclohexane were simultaneously carried out for comparison. Toxicity of the aqueous solutions of alpha-, beta-, and delta- isomers showed an increase while that of the gamma- isomer decreased significantly during the four week experimental period. Aqueous solution of technical HCH was equally toxic as that of the gamma- isomer initially and did not show much decrease in its toxicity at the end. Changes in toxicity of the individual isomer solutions were considered to be due, in part, to interconversions of HCH isomers.

Animals↗
PubMed1980

Isomerization of beta-HCH in aqueous solution.

beta-HCH was shaken with distilled water at 25 +/- 1 degree C for different time intervals and filtered. The ether extract of the filtrate on analysis by gas liquid chromatography showed the presence of four isomers, alpha, beta, gamma and delta, besides other compounds, thereby indicating isomerization of the beta-isomer in aqueous solution. Further, the ether extract, when dried and dissolved in acetone, showed high toxicity to mosquito larvae, flour beetle larvae and house-flies thereby indicating conversion of the inert beta-isomer to more toxic forms corroborating GLC analysis. Acetone solution of pure beta-HCH was found nontoxic against the insects tested.

Animals↗
PubMed1979

Hematological changes produced in mice by ochratoxin A.

The effects of ochratoxin A (5 mg/kg, intraperitoneal) on clotting time, hemoglobin, total count of red blood cells and white blood cells and differential count of white blood cells were studied in mice. This mycotoxin caused a significant decrease in the hemoglobin level and in the total count of red blood cells. Among white blood cells there was a significant increase in small lymphocytes and a significant fall in the count of neutrophils, basophils and monocytes in treated mice. The administration of ochratoxin A also prolonged the clotting time by more than 6-fold.

Animals↗
PubMed1976

Thin layer chromatography of parathion as paraoxon with cholinesterase inhibition detection.

A simple, sensitive, and rapid method is described for the quantitative estimation of ng amounts of parathion (O,O-diethyl O-p-nitrophenyl phosphorothioate) as paraoxon (O,O-diethyl O-p-nitrophenyl phosphate) on thin layer chromatograms. Paraoxon is detected by inhibition, using p-nitrobenzenediazonium fluoroborate as the chromogenic reagent. This chromogenic reagent is more sensitive than Fast Blue B or indoxyl acetate; 0.1 ng may be detected and amounts from 5 to 50 ng may be estimated. The method is a viable alternative to gas chromatographic analysis for parathion.

Animals↗