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Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 541 records · Page 30Linked to original sources
PubMed1988

Recovery of a cell surface fetal antigen from circulating immune complexes of melanoma patients.

A well-characterized 69.5 x 10(3) dalton glycoprotein fetal antigen (FA), isolated from the spent culture medium of a melanoma cell line, UCLA-SO-14 (M14), was utilized to characterize the antigen component of circulating immune complexes (CIC) from melanoma patients. Ten serum samples from five patients with stage II melanoma at 1 and 4 months prior to the clinical detection of recurrent disease were selected for study. The CIC were dissociated with low pH and ultrafiltered through a 100 x 10(3) dalton exclusion limit membrane. The low pH treatment resulted in an increase in antibody titer in eight of ten serum samples. The antibody activity in membrane immunofluorescence was quantitatively inhibited by the filtered antigen fraction and purified FA, suggesting the presence of anti-FA antibodies in the treated serum, which possibly were complexed with FA in the untreated sample. As determined by competitive inhibition in an enzyme-linked immunosorbent assay, the filtrate (antigen fraction) contained an antigen that was immunologically similar to FA. These results clearly demonstrate that FA, expressed on the cell surface of melanoma cells, is present in CIC of selected melanoma patients.

Antigen-Antibody Complex↗
PubMed1988

Impermeant potential-sensitive oxonol dyes: II. The dependence of the absorption signal on the length of alkyl substituents attached to the dye.

We have measured the potential-dependent light absorption changes of 43 impermeant oxonol dyes with an oxidized cholesterol bilayer lipid membrane system. The size of the signal is strongly dependent on the chain length of alkyl groups attached to the chromophore. Dye molecules with intermediate chain lengths give the largest signals. To better understand the dependence of the absorbance signal on alkyl chain length, a simple equilibrium thermodynamic analysis has been derived. The analysis uses the free energy of dye binding to the membrane and the "on-off" model (E.B. George et al., J. Membrane Biol., 103:245-253, 1988a) for the potential-sensing mechanism. In this model, a population of dye molecules in nonpolar membrane binding sites is in a potential-dependent equilibrium with a second population of dye that resides in an unstirred layer adjacent to the membrane. Dye in the unstirred layer is in a separate equilibrium with dye in the bulk bathing solution. The equilibrium binding theory predicts a "sigmoidally shaped" increase in signal with increasing alkyl chain length, even for very nonpolar dyes. We suggest that aggregation of the more hydrophobic dyes in the membrane bathing solution may be responsible for their low signals, which are not predicted by the theory.

Adsorption↗
PubMed1988

Ultrasound diagnosis of multiple cystic encephalomalacia.

Following bacterial meningitis thirty cases of enlarging head were evaluated on ultrasound to find out the cause. Nine out of 30 patients had multiple cystic lesions in both cerebral hemispheres with or without ventriculomegaly. Three patients showed debris in the cysts suggesting pus, which was confirmed on ultrasound-guided aspiration in two and on surgery in one case. Seven out of nine patients had died at the time of writing this communication, suggesting the need for its early detection and timely family counselling. It is stressed that multiple cystic encephalomalacia has a characteristic appearance on ultrasound and all patients with meningitis should be screened routinely so as to detect it at an early stage.

Brain Diseases↗
PubMed1988

Studies on the pathology of experimental zinc deficiency in guinea-pigs.

Zinc deficiency was produced in guinea-pigs by feeding a diet containing 1.25 micrograms Zn per g of diet over a period of 60 days. A significant reduction in serum and tissue (kidney, liver and testis) Zn concentration was observed in the Zn-deficient (ZnD) group. Gross lesions were thickening of skin, atrophy of testis and thyroid and enlargement of adrenals. Histologically, there was parakeratosis, hyperkeratosis and acanthosis in skin, tongue and oesophagus, degeneration and strophy of testis, necrosis of the pancreas, atrophy of the thyroid, atrophy of the zona glomerulosa and hyperplasia of the zona reticularis and medulla of the adrenals. In order to study the response to Zn supplementation, the Zn-replete diet was fed over a period of 15 days to guinea-pigs which had been given the ZnD diet for 45 days. These animals exhibited marked, though not complete, improvement in the pathological changes.

Adrenal Glands↗
PubMed1988

The effects of purified pertussis components and lipopolysaccharide on the results of the mouse weight gain test.

The effects of highly purified components of Bordetella pertussis, that is pertussis toxin (PT) and filamentous haemagglutinin (FHA), and of lipopolysaccharide (LPS) were studied in the active mouse weight gain test (MWGT). The PT when given alone or with other components in various combinations caused weight losses and deaths 2-3 days after inoculation but FHA was not toxic in the MWGT. When FHA was given with PT, the toxic effect of PT was reduced. The LPS caused weight losses at 24 h which decreased when LPS was given with PT. The toxic effects of PT as indicated by late deaths and late weight losses or failure to gain weight continued until 14 days after inoculation. The various components had similar effects on mouse weight gain in both LACA and NIH strains of mice. The doses of PT used in the MWGT caused marked leucocytosis but FHA and LPS did not. No agglutinins appeared in the sera of mice inoculated with various purified components. The components were thus pure and did not contain agglutinogens.

Agglutinins↗
PubMed1988

Studies on the optimal conditions for inactivation of Bordetella pertussis organisms with glutaraldehyde for preparation of a safe and potent pertussis vaccine.

The optimal conditions for inactivation of Bordetella pertussis organisms with glutaraldehyde for the production of a safe and potent whole cell pertussis vaccine were investigated. Two bacterial harvests from B. pertussis strain 10536 were treated with glutaraldehyde, each with 0.025, 0.05 and 0.1% concentrations of glutaraldehyde for 10, 60 and 120 min. The nine types of glutaraldehyde-inactivated pertussis vaccine (GIPV) and conventional heat-inactivated pertussis vaccine (HIPV) preparations made from two bacterial harvests were comparatively evaluated for the mouse weight gain test (MWGT), potency, and the histamine-sensitization (HS) and leucocytosis-promoting-factor (LPF) tests. The minimum period for killing the B. pertussis organisms with glutaraldehyde was greater than 10 min for 0.025%, 10 min for 0.05% and 5 min for 0.1% concentration. The average loss in opacity varied from 5 to 10% for GIPV preparations and was 14% for HIPV preparations. The GIPV preparations except those inactivated with 0.025% glutaraldehyde for 10 min (GIPV-A) were much less toxic than the HIPV preparations in the MWGT. The GIPV-A preparations did not pass the MWGT. The GIPV preparations were also much less toxic in HS and LPF tests than the HIPV preparation. The potency of GIPV preparations inactivated with 0.05% glutaraldehyde for 10 min (GIPV-D) was similar to that of HIPV preparations. The prolonged treatments with glutaraldehyde reduced the potency. The GIPV-D preparation with good potency and less toxicity was found to be inactivated with glutaraldehyde under optimal conditions. All the preparations were innocuous in the abnormal toxicity test.

Aldehydes↗
PubMed1988

Study of fatal burns cases in Kanpur (India).

Epidemiological and medicolegal, including forensic pathological, aspects of 180 cases of fatal burns were studied in Kanpur (India) during the period of one year (October 1985 to September 1986). These constituted 10.79% of the total medicolegal deaths autopsied. Majority of the victims were young Hindu housewives burnt within 5 years of their marriage. The most common source of fire was cooking apparatus like chulha, coalfire, stove or cooking gas. In a substantial number of cases, kerosene oil was poured over the victims and fired with a match stick. About half of the burn cases were accidental, in which cooking on open unguarded flames and loose highly inflammable synthetic sarees of the victims can be blamed. Among the others who died in suspicious circumstances, i.e., burnt alive or forced to commit suicide by fire, dowry and family quarrels and marital disharmony were the two important predisposing factors. Illiteracy, arranged and child marriages, joint family structure, oedipal dominance of mother-in-laws, unemployment and economic dependence of the husband on the parents, near complete dependence of women on their husbands and inlaws, and lack of social security amongst Hindu females were other contributory factors affecting the incidence in some way. Male burn deaths were few and usually accidental.

Accidents↗
PubMed1988

Cysticercosis of the brain shown by magnetic resonance imaging.

Fifteen patients in whom the diagnosis of cysticercosis of the brain was suggested by computed tomography (CT) were further studied with magnetic resonance imaging (MRI). Besides lesions in the substance of the hemispheres, cysts were found adjacent to and within the ventricles, the brainstem, cerebellum and subarachnoid space. Magnetic resonance imaging showed brain involvement out of proportion to what was shown by CT. The eccentrically placed mural nodule within a cyst, the pathognomonic lesion of cysticercosis, was seen in all cases with MRI. The various stages of development of the cysticercus larva were seen in one individual. An attempt is made to illustrate the various stages of development by means of MR images, and a possible pathological explanation is offered. The authors believe that MRI provides diagnostic information in this disease and dispenses with the need for enhanced CT examination.

Adolescent↗
PubMed1988

Intracellular sodium in proximal tubules of diabetic rats. Role of glucose.

Renal hypertrophy is a common consequence of diabetes mellitus that precedes and possibly accounts for the increased glomerular filtration rate. We have postulated that the glucose-mediated increase in the intracellular concentration of sodium [Na]i initiates the chain of events leading to the increase in cell size and eventually cell number. Experiments were conducted on Sprague-Dawley rats made diabetic by the intravenous injection of 45 mg/kg body wt of streptozotocin dissolved in a 5 mM citrate buffer solution. Control animals were injected with the vehicle alone. Ninety-six hours and 11 weeks later, measurements of [Na]i were done by NMR spectroscopy on suspensions of proximal tubules, using dysprosium tripolyphosphate as an extracellular shift reagent. At 96 hours after the induction of the diabetes, there was a 60% increase in [Na]i compared to control (P less than 0.01). No further increase in [Na]i was observed during the subsequent 11 weeks of observation. Addition of ouabain (1.0 mM) resulted in a fourfold increase in [Na]i in tubules from control animals, and a 2.5-fold increase in tubules from 96-hour diabetic rats. Ouabain-inhibitable Na+-K+-ATPase activity was substantially higher in the renal tubules of diabetic rats, the increase being proportional to that of [Na]i. In order to ascertain the effect of hyperglycemia on [Na]i, proximal tubules prepared from kidneys of normal and diabetic rats were exposed to low (5 mM) and high (25 mM) concentration of glucose in the media.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effect of experimental zinc deficiency and repletion on some immunological variables in guinea-pigs.

1. Cellular and humoral immune responses were studied in guinea-pigs fed on zinc-deficient (ZnD), Zn-adequate (control) and Zn-replete diets containing 1.25, 50 and 100 mg Zn/kg diet respectively. 2. It was found that the ZnD guinea-pigs had significantly decreased ability to elicit delayed-type hypersensitivity (DTH) response against sheep erythrocytes as compared with controls on the 9th day of immunization. This was further substantiated by histological examination of DTH-positive skin sections. 3. A significant reduction in direct splenic plaque-forming-cell response and haemagglutinating-antibody titre was also observed in ZnD guinea-pigs. 4. Serum electrophoretic studies revealed a highly disordered protein profile with a significantly depressed value for gamma-globulin. 5. Zn repletion of the previously ZnD group resulted in marked, though incomplete, restoration of immunological responses.

Animals↗
PubMed1988

Fine catheter peritoneal cytology for the acute abdomen: a randomized, controlled trial.

A randomized, controlled clinical trial, of sequential design, was undertaken to determine whether fine catheter aspiration cytology of the peritoneal cavity, using the percentage of neutrophils in the sample as the main test marker, reduces errors about urgent laparotomy in patients admitted to a surgical unit with acute abdominal pain. One hundred and forty-four patients with acute abdominal pain were studied. Of these, 26 were excluded because the test was unlikely to be useful and 20 did not consent. Conventional clinical assessment was undertaken and then the subjects were randomly allocated to have a peritoneal cytology test or not. After the test result was made available, the surgeon(s) decided whether to operate or continue conservative treatment. The correct decision was later ascertained by a blinded clinical referee. With the entry of the 98th patient the difference between the groups achieved the 5% significance level. The groups were well-matched in regard to demographic and other variables. The decision about urgent laparotomy was incorrect in only 8.2% of the test patients, compared with 28.6% of the others. It is concluded that fine catheter aspiration cytology of the peritoneal cavity is likely to reduce the numbers of unnecessary or delayed laparotomies when used in most patients admitted with acute abdominal pain.

Abdomen, Acute↗
PubMed1988

The role of fine needle aspiration cytology (FNAC) in the diagnosis of breast masses in males.

The role of fine needle aspiration cytology (FNAC) in the management of male breast masses has been reviewed. Forty-four male patients have been investigated in this way with one carcinoma being diagnosed. The cytological characteristics of the patients in this series with gynaecomastia and carcinoma of the male breast have been described. Although clinically the distinction between male breast carcinoma and gynaecomastia is often difficult, FNAC is an important aid in making this distinction. FNAC is recommended for the evaluation of all breast masses in adult men.

Aged↗
PubMed1988

Intracellular free magnesium in hypertension: relation to peripheral insulin resistance.

In order to study the importance of altered intracellular ion metabolism in hypertension, we used 31P nuclear magnetic resonance (NMR) spectroscopy to measure intracellular free magnesium levels in normotensive (n = 19), essential hypertensive (n = 17) and diet-controlled diabetic (n = 6) subjects given a standard 100-g oral glucose load. The intracellular Mg level was significantly lower in hypertensives compared with normotensives (183 +/- 7 versus 232 +/- 10 mumol/l, P less than 0.001), and for all subjects was closely linked to both systolic (r = -0.84, P less than 0.001) and diastolic (r = -0.76, P less than 0.001) pressure. Hypertensives also showed a significantly greater insulinaemic response to glucose loading (P less than 0.001), and intracellular Mg was also closely and inversely linked to the integrated insulin response (r = -0.78, P less than 0.001). Despite the absence of hyperinsulinaemia, diabetics had the lowest intracellular Mg levels (156 +/- 8 mumol/l). Thus, suppressed intracellular Mg is linked to hypertension and to decreased tissue insulin sensitivity, and is not consequent to the hyperinsulinaemia itself. We suggest that intracellular Mg may provide a common pathophysiological basis for understanding the clinical association of hypertension and diabetes mellitus.

Blood Pressure↗
PubMed1987

Improvement in the quality of gynaecological smears using a cytobrush.

For accurate cervical cytology an adequate sample of cells must be obtained from the squamocolumnar junction. In 100 patients conventional smears were compared with smears and membrane filter preparations made using a cytobrush. A satisfactory cell smear was obtained in 39% of patients using the conventional method and in 97% the cytobrush. When membrane filter preparations were used in conjunction with cytobrush smears, adequate cytological samples were obtained from all patients.

Cervix Uteri↗
PubMed1987

Studies on the mechanism of decreased NMR-measured free magnesium in stored erythrocytes.

31P-NMR spectra have been recorded on erythrocytes stored at 4 degrees C in various preservation media. Storage was always associated with an upfield shift of the inorganic phosphate (Pi) resonance and a pronounced upfield shift of the ATP beta resonance, indicating decreased intracellular pH (pHi) and decreased intracellular free magnesium ([Mg2+]i). The decreased [Mg2+]i occurred in preservation media not containing citrate and even in media supplemented with Mg2+. It could not be attributed to the changes in pHi, Na+, K+, lactate, Pi or 2,3-diphosphoglycerate, that occur with storage. The decrease in [Mg2+]i was largely reversed when stored cells were incubated for 1 h at 37 degrees C in fresh plasma. Stored cells were found to contain significant amounts of inorganic pyrophosphate, up to about 200 mumol per liter cell water. Being a tight binder of Mg2+, pyrophosphate could account for some of the observed decrease in [Mg2+]i. Additional mechanisms may involve precipitation of some other Mg2+ complex during cold storage or enhancement of Mg2+ binding to membrane components.

Blood Preservation↗