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Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 19 recordsLinked to original sources
PubMed1992

Lead inhibits 1,25-dihydroxyvitamin D-3 regulation of calcium metabolism in osteoblastic osteosarcoma cells (ROS 17/2.8).

We have determined the dose-response of 1,25-dihydroxyvitamin D-3 (1,25-(OH)2D3) on the intracellular free calcium-ion concentration ([Ca2+]i) in the osteoblastic osteosarcoma cells, ROS 17/2.8, using 19F-NMR and the intracellular divalent cation indicator, 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5F-BAPTA). The dose-response demonstrated an inverted U-shaped relationship with maximal elevation of [Ca2+]i at doses of 1 to 10 nM 1,25-(OH)2D3. At 10 nM, 1,25-(OH)2D3 elevated the [Ca2+]i from a control level of 118 +/- 4 nM to a peak value of 237 +/- 8 nM within 40 min. 1,25-(OH)2D3 also increased the initial rate of Ca2+ influx into ROS 17/2.8 cells, measured by 45Ca uptake, with a dose-response relationship which paralleled its effect on [Ca2+]i. Treatment of ROS 17/2.8 cells with Pb2+ at 1 and 5 microM significantly increased [Ca2+]i but significantly reduced the 1,25-(OH)2D3-induced elevation of [Ca2+]i. Simultaneous treatment of naive cells with 1,25-(OH)2D3 and Pb2+ produce little reduction of 1,25-(OH)2D3-induced 45Ca uptake while 40 min treatment with Pb2+ before addition of 1,25-(OH)2D3 significantly reduced the 1,25-(OH)2D3-induced increase in 45Ca influx. These findings suggest that Pb2+ acts by inhibiting 1,25-(OH)2D3-activation of Ca2+ channels and interferes with 1,25-(OH)2D3 regulation of Ca2+ metabolism in osteoblastic bone cells.

Animals↗
PubMed1992

Cocaine induces intracellular free Mg deficits, ischemia and stroke as observed by in-vivo 31P-NMR of the brain.

31P-NMR spectroscopic studies were performed in vivo on brains of rats administered cocaine. Cocaine.HCl (1-5 mg/kg) administered systemically to lightly anesthetized rats resulted in significant and progressive deficits in whole brain intracellular free Mg ([Mg2+]i). Intracellular pH (pHi) also fell in a progressive manner but only after a significant fall in brain [Mg2+]i was noted. Both [Mg2+]i and pHi returned to normal in most rats. Brains of rats that exhibited stroke-like events, however, demonstrated continued intracellular acidosis associated with progressive loss of phosphocreatine and elevation of Pi up until death. These observations are consistent with the tenet that injection of cocaine can result in severe cerebral vasospasm, ischemia and rupture of cerebral blood vessels as a consequence of depletion of brain [Mg2+]i.

Animals↗
PubMed1992

Direct sequence analysis of the t(14;18) chromosomal translocation in Hodgkin's disease.

There have been conflicting reports about the occurrence of the t(14;18) chromosomal translocation in Hodgkin's disease. A polymerase chain reaction analysis of biopsy specimens from 21 patients with Hodgkin's disease (HD) has shown the presence of the t(14;18) translocation in four cases (20%). All four patients had nodular sclerosing HD. Direct sequencing of the amplified 14q+ junctions established that the BCL-2 (major breakpoint region) sequence was fused to an Ig joining region (JH) (J6 in all four cases). Different breakpoints were observed in each case but were similar in nature to the breakpoints described in follicular lymphoma. The exact nature and cell of origin in HD remains obscure, although the presence of the t(14;18) translocation may reflect either a B-cell origin in these cases or associated lymphoid hyperplasia.

Adolescent↗
PubMed1992

Multinuclear NMR studies of intracellular cations in perfused hypertensive rat kidney.

We have investigated hypertension-associated alterations in intracellular cations in the kidney by measuring intracellular pH, free Mg2+, free Ca2+, and Na+ concentrations in perfused normotensive and hypertensive rat (8-14 weeks old) kidneys using 31P, 19F, and double quantum-filtered (DQ) 23Na NMR. The effects of both anoxia and ischemia on the 23Na DQ signal confirmed its ability to detect changes in intracellular Na+. However, there was a sizable contribution of the extracellular Na+ to the 23Na DQ signal of the kidney. The intracellular free Ca2+ concentration, measured using 19F NMR and 5,5'difluoro-1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid, also increased dramatically during ischemia; the increase could be partly reversed by reperfusion. No significant differences were found between normotensive and hypertensive kidneys in the ATP level, intracellular pH, intracellular free Mg2+, and the 23Na DQ signal or in the extent of the extracellular contribution to the 23Na DQ signal. Oxygen consumption rates were also similar for the normotensive (5.02 +/- 0.46 mumol of O2/min/g) and hypertensive (5.47 +/- 0.42 mumol O2/min/g) rat kidneys. The absence of a significant difference in intracellular pH, Na+ concentration, and oxygen consumption between normotensive and hypertensive rat kidneys suggests that an alteration in the luminal Na+/H+ antiport activity in hypertension is unlikely. However, a highly significant increase (64%, p less than 0.01) in free Ca2+ concentration was found in perfused kidneys from hypertensive rats (557 +/- 48 nM, blood pressure = 199 +/- 5 mmHg, n = 6) compared with normotensive rats (339 +/- 21 nM, blood pressure = 134 +/- 6, n = 4) indicating altered renal calcium homeostasis in essential hypertension. An increase in intracellular free Ca2+ concentration without an accompanying change in the intracellular Na+ suggests, among many possibilities, that the Ca2+/Mg(2+)-ATPase may be inhibited in the hypertensive renal tissue.

Animals↗
PubMed1992

Aspiration cytodiagnosis of breast carcinoma in pregnancy and lactation with immunohistochemical and electron microscopic study of an unusual mammary malignancy with pleomorphic giant cells.

We have reviewed our experience with 8,706 needle aspiration cytology (NAC) of the breast which were done from January 1983 to June 1991. During our study we diagnosed four cases of breast carcinomas (three ductal type and one with pleomorphic giant cells) in pregnant or lactating women; in all of these the cytologic findings corresponded with the subsequent tissue diagnosis and cell block preparations. Considering that carcinoma of breast during pregnancy and lactation is rare and is second only to cervical cancer, it was felt that its diagnosis by NAC was useful for timely management. In the case in which pleomorphic giant cells were present as an integral component of the tumour, immunohistochemical and electron microscopic study was done. This is discussed in view of our recent experience with this unusual tumour.

Adult↗
PubMed1992

Needle aspiration cytology, immunocytochemistry, and electron microscopic study of unusual pancreatic carcinoma with pleomorphic giant cells.

Needle aspiration cytology, immunocytochemistry, and electron-microscopic findings are presented in three cases of an unusual pancreatic carcinoma in which pleomorphic giant cells formed an integral part of the tumour. All three patients were elderly males (age range 66-83 years) and had pancreatic masses. Notable cytologic features in all cases were the presence of bizarre mononucleated and multinucleated, poorly cohesive tumour giant cells, rare spindle cells, with occasional cannibalism and cytophagocytosis. Immunocytochemical study of aspirated material showed diffuse staining of cytokeratin and EMA within the tumour cells, while B 72.3 was seen as focal trace stain. Electron microscopy of aspirated material demonstrated epithelial features and these were characterised by the presence of tonofilaments and surface microvilli. Based on our findings, it is felt that the bizarre giant cells in this unusual variant of pancreatic carcinoma are of epithelial origin. The differential diagnosis of other tumours that may be associated with predominant giant cells in pancreatic aspirates is appropriately discussed.

Aged↗
PubMed1992

Monoclonal antibody-based ELISA to detect glycoprotein tumor-associated-antigen-specific immune complexes in cancer patients.

This report describes the development and applicability of a tumor-associated-antigen-specific immune complex (IC) detection assay to denote the presence of tumor cells in a cancer host. This assay utilizes a murine monoclonal antibody, AD1-40F4, which was produced to a glycoprotein tumor-associated antigen (TAA). In Western blot, the murine monoclonal antibody recognized a 90-100 kD subunit of the antigen. This antigen is immunogenic in cancer patients and induces formation of endogenous antigen-antibody complexes. Analysis of 250 sera from normal individuals and 419 sera from cancer patients revealed that a significantly (P less than .0005) greater proportion (234/419; 55.9%) of cancer sera was positive for the marker than the normal sera (8/250; 3.2%). The incidence of the 90 kD-TAA-specific-IC was consistently and significantly higher in melanoma (58.5%; 38/65), sarcoma (52.9%; 83/157), and carcinoma of breast (50.9%; 58/114), lung (68.2%; 30/44), and colon (64.1%, 25/39) than in the normal group. The age of serum donors did not affect the incidence of the reactivity. Also, at least in the cancer group the gender of the serum donor did not affect the incidence of the 90 kD-TAA-specific-IC positivity. In a retrospective study where sequential serum samples obtained postoperatively from 105 patients with melanoma were analyzed, the 90 kD-TAA-specific-IC could be detected in 72 (69%) of patients several years before the appearance of clinically detectable disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

A protease-sensitive site in the proposed Ca(2+)-binding region of human serum amyloid P component and other pentraxins.

Serum amyloid P component (SAP) is a decamer of 10 identical 25.5-kDa subunits. Limited proteolysis of SAP with alpha-chymotrypsin cleaves the subunit into two fragments of 18 and 7.5 kDa, although the fragments stay together in the decamer under nondenaturing conditions. Proteolysis does not occur in the presence of Ca2+ (10 mM). Cleavage with alpha-chymotrypsin prevents the Ca(2+)-dependent binding of SAP to zymosan extract, nucleosomes, and DNA. The alpha-chymotrypsin cleavage site identified is in a region of SAP that is highly conserved in members of the human C-reactive protein (CRP) family of proteins (pentraxins) to which SAP belongs and is similar to the Ca(2+)-binding site in calmodulin and related Ca(2+)-binding proteins (Nguyen, N.Y., Suzuki, A., Boykins, R.A., & Liu, T.-Y., 1986, J. Biol. Chem. 261, 10456-10465). Treatment of SAP with other proteases (trypsin, Pronase, and Nagarse protease) yields fragmentation patterns upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) that are similar to those obtained with alpha-chymotrypsin. Two other members of the pentraxin family of proteins, hamster female protein and rabbit CRP, also exhibit similar fragmentation patterns on SDS-PAGE when treated with the various proteases. Recently, it has been shown that the homologous protein, human CRP, is cleaved in the same homologous position as cleavage of SAP by alpha-chymotrypsin, resulting in the loss of Ca(2+)-binding (as shown by equilibrium dialysis) and Ca(2+)-dependent binding reactivities (Kinoshita, C.M., Ying, S.-C., Hugli, T.E., Siegel, J.N., Potempa, L.A., Jiang, H.J., Houghten, R.A., & Gewurz, H., 1989, Biochemistry 28, 9840-9848).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Complement-dependent lysis of tumor cells by a baboon IgM antibody to a tumor-associated antigen.

We developed a high-titer polyclonal antiserum to a glycoprotein tumor-associated antigen (TAA) by immunization of a baboon with the purified glycoprotein antigen. The baboon serum was fractionated into IgG and IgM components by DEAE Affi-Gel blue chromatography. The ability of the baboon IgM anti-TAA antibody to effect tumor cell lysis in the presence of complement was tested using a chromium-release assay. The baboon antibody was able to lyse melanoma target cells (20.8%-71.4% cytolysis), breast carcinoma cells (36.5%-38.9% cytolysis), and a neuroblastoma cell line (35.5% cytolysis) in the presence of complement but did not effect significant lysis of autologous lymphoblastoid cell lines (4.9% cytolysis) or peripheral blood lymphocytes from healthy volunteers (12.6% cytolysis). Cytolysis of melanoma target cells was completely inhibited by preabsorption of the IgM anti-TAA antibody with UCLA-SO-M14 (M14) cells and partially inhibited by preabsorption with several other melanoma cell lines. There was no significant inhibition of tumor cell lysis after preabsorption of the antibody with lymphoblastoid cell lines. Complement-dependent lysis of M14 targets could be blocked by addition of the purified antigen to the antibody prior to incubation with the tumor cells. Our results suggest that the glycoprotein TAA resides on the tumor cell surface and that the baboon IgM anti-TAA antibody recognizes the antigen on the cell surface and is able to fix complement and effect the lysis of the tumor cells.

Animals↗
PubMed1992

Intestinal lymphangiectasia: evaluation by CT and scintigraphy.

Intestinal lymphangiectasia caused severe diarrhea and generalized edema in a 40-year-old man. The diagnosis was established by clinical, laboratory, and duodenal biopsy findings. The abnormalities detected on computed tomography (CT) and scintigraphy using 99mTc human serum albumin are herein described and pertinent literature is briefly reviewed.

Adult↗
PubMed1992

Does blood pressure reduction necessarily compromise cardiac function or renal hemodynamics? Effects of the angiotensin-converting enzyme inhibitor quinapril.

Clinical studies indicate that the angiotensin-converting enzyme inhibitor quinapril is an effective antihypertensive agent when administered once daily. At the end of a 4-week, double-blind crossover trial comparing quinapril and placebo, patients were admitted for a hemodynamic profile study 12 hours after taking the previous dose. A final 20 mg dose of quinapril had no additional effect on blood pressure. This is interesting inasmuch as the plasma half-life of the active metabolite quinaprilat is approximately 2 hours and the effective accumulation half-life is approximately 3 hours. The blood pressure reduction in patients with mild hypertension receiving long-term quinapril therapy may be more closely related to prolonged angiotensin-converting enzyme inhibition or to an effect on tissue angiotensin II concentration than to the plasma half-life. This may be the case particularly for cardiac output and renal circulation, because quinapril lowers total vascular resistance without increasing cardiac output or disturbing autoregulation of renal blood flow. Reduced ventricular wall stress, improved diastolic function, and lower renal perfusion pressure may spare cardiac function and glomeruli from hypertensive vascular damage.

Adult↗
PubMed1992

Cine MR voiding cystourethrogram in adult normal males.

Cine voiding cystourethrogram was performed in 15 normal subjects using T1-weighted Turbo FLASH sequence. It showed the sequence of emptying of bladder, detrusor muscle contraction, opening of the sphincters, and various parts of urethra. It was found to be a good noninvasive test to study the dynamics of lower urinary tract without disturbing the state of the physiology.

Adult↗
PubMed1992

Determination of antibodies to pertussis toxin in working reference preparations of anti-pertussis sera from various national control laboratories.

Working reference preparations of anti-pertussis sera from various National Control Laboratories were assayed for anti-PT antibodies by standardized ELISA and toxin neutralization (Nt) test. Both the ELISA and Nt tests gave highly reproducible results for various preparations when these preparations were assayed repeatedly on different days. Various working reference preparations were assigned units against the proposed International standard for anti-pertussis serum (JNIH-10) assuming its unitage of 250. Assigning unitage to various preparations would help in comparing results of ELISA and Nt tests for anti-PT antibodies reported in various studies.

Antibodies, Bacterial↗
PubMed1992

p53 expression in Reed-Sternberg cells of Hodgkin's disease.

Mutation of the p53 protein may represent the commonest genetic event in human malignancy. Abnormal p53 expression has been reported in a variety of carcinomas, sarcomas and lymphoid neoplasms; however there is little information in relation to Hodgkin's disease. The expression of the nuclear phosphoprotein was investigated in paraffin-embedded biopsies from fifty patients with Hodgkin's disease using a polyclonal antibody, CM-1 and in snap-frozen material with monoclonal antibodies, PAb 1801 and PAb 240. Specifically, immunoreactivity was localised to the Reed-Sternberg cells or mononuclear variants in both nodular sclerosing (86% cases) and mixed cellularity (57% cases) subtypes of Hodgkin's disease. However, no positive staining was found in our cases of nodular lymphocyte predominant type Hodgkin's disease. Serial biopsies following recurrence of disease demonstrated consistent results. It is suggested that overexpression of p53, probably mutant, may have a role in the tumorigenesis of Hodgkin's disease.

Hodgkin Disease↗
PubMed1992

Nutritional modulators of lipoprotein metabolism in patients with risk factors for coronary heart disease: diet and moderate exercise trial.

To study the role of diet as a risk factor for coronary heart disease (CHD), 463 adults (25-65 years, 419 males) at risk of or with CHD were assigned to group A (n = 231) receiving a cardiovasoprotective diet or group B (n = 232) receiving a normal diet in a randomized, single-blind fashion. Age, sex, risk factors and incidence of CHD were comparable between the two groups. Group A received a significantly higher percentage of calories in relation to complex carbohydrates, vegetable proteins, polyunsaturated fatty acids, and had a higher polyunsaturated:saturated fatty acid (P:S) ratio compared to control group B, which received more saturated fat and cholesterol. Group A also received more soluble dietary fiber and magnesium (Mg) and was physically more active than group B. Exercise and dietary adherence were tested by a questionnaire. After 12 weeks, results indicated a significant decrease in mean serum total cholesterol (9.0 vs 3.1%), low-density-lipoprotein cholesterol (LDL-C) (9.8 vs 3.8%) and triglyceride (11.1 vs 5.4%), and an increase in serum Mg (8.5%) in the intervention group compared to initial levels. No significant changes in mean levels were noted in the control group. Body weight significantly decreased and physical activity was significantly higher in the intervention group compared to the control group during the 12-week followup on similar intakes of energy. There were insignificant changes in high-density-lipoprotein cholesterol (HDL-C) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗