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Biomedical subjects

R K Gupta

Publications and source records attributed to R K Gupta.

At least 343 records · Page 19Linked to original sources
PubMed1994

The t(14;18) chromosomal translocation and Bcl-2 protein expression in Hodgkin's disease.

A polymerase chain reaction analysis of biopsy specimens from a total of 52 patients with Hodgkin's disease has revealed the presence of the t(14;18) chromosomal translocation in 14 cases (28%). Twelve involved the major breakpoint region and two included the minor cluster region of the bcl-2 gene. Direct sequencing of the amplified 14q+ junctions from the initial four positive cases (from 21 biopsies) has been previously published and demonstrated the similarity in nature of the break-points to those described in follicular lymphoma and lymphoid hyperplasia. The 52 biopsies have also been studied with a monoclonal antibody to immunolocalize the Bcl-2 protein. In all cases Bcl-2 positivity was observed in the majority of surrounding lymphocytes. However, in 11 cases, positive immunostaining in the Sternberg-Reed cells was also observed. Three of these cases contained the t(14;18) translocation, but 11 cases which were positive for the t(14;18) by PCR did not show Bcl-2 protein staining in the Sternberg-Reed cells. This data confirms the presence of t(14;18) in 28% of biopsies from Hodgkin's disease and demonstrates Bcl-2 protein staining in a variable proportion of Sternberg-Reed cells of some cases.

Base Sequence↗
PubMed1994

Is the higher incidence of ischemic disease in patients with hypertension and diabetes related to intracellular depletion of high energy metabolites?

To study mechanisms underlying ischemia in hypertension and non-insulin dependent diabetes mellitus (NIDDM), 31P-magnetic resonance spectroscopy was used to evaluate adenosine triphosphate and 2,3 diphosphoglycerate (2,3 DPG) levels in erythrocytes of control (n = 21), hypertensive (n = 22), and NIDDM (n = 10) subjects. Compared to adenosine triphosphate levels in controls (2.22 +/- 0.10 mM), both hypertensive (1.89 +/- 0.10 mM, sig = 0.05 versus normal) and NIDDM subjects (1.57 +/- 0.13 mM, sig = 0.05 versus normal) exhibited lower values. NIDDM subjects also displayed suppressed levels of 2,3 DPG (6.84 +/- 0.48 mM, sig = 0.05 versus normal and EH), compared to hypertensives (8.34 +/- 0.27 mM). These data suggest cellular energy metabolism is disrupted in hypertension and NIDDM. Both conditions may thereby sensitize tissues to ischemic damage, lower adenosine triphosphate levels by decreasing energy reserves, and lower 2,3 DPG levels by inhibiting hemoglobin-oxygen dissociation.

2,3-Diphosphoglycerate↗
PubMed1993

31P-NMR study of transient ischemia in rat hippocampal slices in vitro.

Intracellular high energy phosphates (HEP) were monitored in rat hippocampal slices in vitro by 31P-NMR during continuous superfusion, no flow and reperfusion in order to model the changes which occur during cerebral ischemia and reperfusion in vivo. With continuous superfusion, stable intracellular HEP resonance signals were observed for over 4 h. When superfusion was stopped, there were rapid decreases in pH and phosphocreatine levels followed by slower loss of ATP. These changes are similar to those observed during cerebral ischemia in vivo by 31P-NMR. Upon reperfusion, the pH returned to normal, but the extent of HEP recovery depended on the length of time superfusion was halted. Following a 10 min ischemic period HEP levels returned to greater than 90% of preischemic values, while following a 16 min ischemic period there was only 60% recovery. Superfusion with low calcium, high magnesium medium significantly improved the recovery of HEP following 16 min of ischemia to 80% of preischemic levels. These data support the hypothesis that calcium influx during and following ischemia can disrupt energy metabolism in the hippocampus, and that magnesium can have a protective action on cellular energy status, perhaps by further blocking calcium influx.

Adenosine Triphosphate↗
PubMed1993

Low extracellular magnesium induces intracellular free Mg deficits, ischemia, depletion of high-energy phosphates and cardiac failure in intact working rat hearts: a 31P-NMR study.

Hemodynamic and 31P-NMR spectroscopic studies were performed on intact, perfused working rat hearts exposed to low (0.3 mM) extracellular Mg([Mg2+]o). Low [Mg2+]o perfusion resulted in rapid and significant falls in cardiac output, coronary flow, stroke volume, developed pressure and the rate-pressure product. Concomitant with this O2 consumption decreased and lactate production increased. Hearts perfused with 0.3 mM, instead of 1.2 mM, [Mg2+]o exhibited significant reductions in [ATP], [PCr], intracellular free Mg ([Mg2+]i), and pHi; a marked rise in intracellular Pi corresponding to a precipitous fall in the cytosolic phosphorylation potential was seen. Reintroduction of 1.2 mM [Mg2+]o failed to reestablish either normal hemodynamics, or high-energy phosphates and intracellular Pi, suggesting irreversible myocyte injury. These observations are consistent with the tenet that low [Mg2+]o can result in marked reduction in oxygen and substrate delivery to the cardiac myocytes, probably as a result of coronary vasoconstriction.

Animals↗
PubMed1993

Mutation of p53 in primary biopsy material and cell lines from Hodgkin disease.

The p53 tumor-suppressor gene encodes a nuclear phosphoprotein that arrests cell cycle progress at G1. It may facilitate DNA damage repair and is frequently mutated in many human tumors. Hodgkin disease, a malignant condition of the lymphoid system, is characterized by the presence of Reed-Sternberg cells and mononuclear variants (Hodgkin cells), whose etiology remains unknown. The large multinucleated Reed-Sternberg cells often comprise < 1% of the total cell population within a biopsy specimen and are thought to be the neoplastic component in an admixture of reactive cells. It has been shown in the large majority of cases that up to 60% of these multinucleated cells react with CM-1, an anti-p53 antibody. However, whether this "overexpression" of p53 protein reflects abnormality at the DNA level can no longer be assumed by immunocytochemistry alone. p53 from six Hodgkin disease-derived cell lines was examined by immunoprecipitation, polymerase chain reaction (PCR)-single-strand conformation polymorphism analysis, and sequencing. In one cell line, point mutations were identified in exons 5 and 8 of p53. Sequencing of cloned PCR products confirmed the mutations to be on different alleles. A strategy involving extraction of nuclei followed by enrichment by flow cytometry was used to determine whether p53 overexpression in the Reed-Sternberg cells from patient biopsy material was due to mutations in this gene. Single-strand conformation polymorphism revealed additional bands in the polyploid nuclear preparations, suggesting abnormalities, and sequence analysis confirmed the presence of point mutations.

Base Sequence↗
PubMed1993

NMR studies of the effect of hyperglycemia on intracellular cations in rat kidney.

Alterations in intracellular cation concentrations in the kidney during hyperglycemia may play a role in a number of complications associated with diabetes mellitus such as renal hypertrophy and hypertension. In this study, we have investigated the effect of 25 mM glucose on intracellular pH and free Mg2+, free Ca2+, and Na+ concentrations in the perfused kidneys of Sprague-Dawley rats using 31P, 19F, and 23Na triple-quantum filtered NMR. No significant alteration occurred in the intracellular free Mg2+ concentration, pH, or ATP concentration during hyperglycemia. However, a sizable (approximately 50%) increase in the intracellular Na+ concentration was inferred from 23Na triple-quantum filtered NMR after 30-45 min of perfusion with 25 mM glucose. Intracellular free Ca2+, measured to be 390 +/- 15 nM at 5 mM glucose, increased significantly (95%; p < 0.001) to a value of 765 +/- 28 nM after 30 min of perfusion with 25 mM glucose. This effect of glucose was reversible. Only small increases (< or = 20%) in free Ca2+ were found with addition of comparable concentrations of a nontransportable sugar (20 mM mannitol), indicating that glucose entry into the cell (through the Na+/glucose cotransporter) plays a role in causing the free Ca2+ increase. No effect on free Ca2+ was however, seen with 1 mM ouabain, which caused a sizable increase in intracellular Na+, indicating that Na+/Ca2+ exchange does not play a significant role in the maintenance of low intracellular free Ca2+ in the kidney and that the observed increase in free Ca2+ is probably due to a decrease in the Ca2+/Mg(2+)-ATPase activity during hyperglycemia. Increased concentrations of Na+ and free Ca2+ during hyperglycemia may be involved in the mechanism of renal hypertrophy and hypertension, frequently associated with diabetes mellitus.

Animals↗
PubMed1993

Adrenal tumor complicating untreated 21-hydroxylase deficiency in a 5 1/2-year-old boy.

OBJECTIVE: A 5 1/2-year-old boy presenting with virilization was diagnosed as having classic 21-hydroxylase deficiency complicated by an adrenal tumor. We attempted to document a reduction in the size of the tumor with glucocorticoid therapy. DESIGN: Case study. SETTING: Referral center. INTERVENTION: Glucocorticoid therapy was instituted for congenital adrenal hyperplasia. Surgery for the adrenal mass was deferred, and the size of the mass was monitored by serial ultrasonography. RESULTS: Baseline values of serum 17 alpha-hydroxyprogesterone (186.6 nmol/L) and testosterone (24.7 nmol/L [7.1 ng/mL]) were elevated. After instituting steroid treatment, 17 alpha-hydroxyprogesterone was suppressed (13.0 nmol/L), and testosterone remained undetectable on follow-up. However, the size of the mass increased during 6 months. Unilateral adrenalectomy performed at that time revealed a well-encapsulated adenoma in a hyperplastic gland. CONCLUSIONS: Untreated classic congenital adrenal hyperplasia may be complicated by an adrenal tumor even at a young age. Suppression of adrenal androgens by glucocorticoid therapy was not accompanied by regression of the tumor in our patient.

Adenoma↗
PubMed1993

Fine-needle aspiration cytodiagnosis of breast masses in pregnant and lactating women and its impact on management.

We reviewed our experience with 9,726 cases of fine-needle aspiration cytology of the breast that were done from January 1983 to February 1992. During our review, we found that 214 aspirates had been submitted from pregnant and lactating women for the investigation of breast mass(es). Despite a variable clinical presentation and spectrum of cytologic findings, we considered the application of aspiration cytology in these women as useful as in the nonpregnant-nonlactating women for management decision. A team approach between the clinician and cytopathologist was always maintained; with this approach, the false-positive or -negative diagnoses were reduced to almost nil. In all cases in which the cytodiagnosis of carcinoma of breast was made, the findings corresponded with subsequent cell blocks from the aspirate and tissue examination. Benign lesions were diagnosed cytologically with minimal difficulty, and all aspirates that were less than optimal for cytodiagnosis were repeated to minimize the chance of missing an abnormality. All the benign lesions were followed throughout pregnancy, postpartum, and thereafter; if the mass persisted, the aspiration was repeated. With this protocol of follow-up, the need for a customary liberal surgical biopsy was reduced to a minimum.

Adolescent↗
PubMed1993

Needle aspiration cytology, immunocytochemistry, and electron microscopic study in a case of carcinoid of the male breast.

The diagnosis of a primary carcinoid of breast in a 68-yr-old male was initially made from a sample of needle aspirate. The cytodiagnosis was supported by histochemical and immunocytochemical studies which showed positivity for argyrophilic granules by Grimelius stain and positive staining for chromogranin. A subsequent cell block of the aspirate and biopsy of the tumour confirmed the cytodiagnosis. Electron microscopic study of the material further demonstrated the presence of neurosecretory granules in the malignant cells. Mastectomy with axillary node dissection was performed and showed no residual or metastatic tumour. No primary tumour was found elsewhere. This case illustrates the importance of needle aspiration cytology in the diagnosis of carcinoid tumour which is very rare in the male breast.

Aged↗
PubMed1993

Cytodiagnosis of pseudomyxoma peritonei in cases suspected of ovarian tumours.

The cytologic features in four cases of pseudomyxoma peritonei are described in ascitic fluid specimens which were received from female patients suspected of ovarian masses. The findings in the fluid included cells of mesothelial origin and spindle-shaped fibroblasts with a significant amount of background mucin. This was confirmed by mucicarmine and Alcian blue stains. A cytologic diagnosis of pseudomyxoma peritonei was possible in all four cases. The above findings were further substantiated since mucinous ovarian neoplasms were found in all the cases.

Adult↗
PubMed1993

Sonourethrography in the evaluation of anterior urethral strictures: correlation with radiographic urethrography.

A total of 30 patients with suspected urethral strictures underwent sonographic and roentgenographic urethrograms. Two patients showed a normal anterior urethra in the sonourethrogram; 29 strictures were diagnosed in the remaining 28 patients, 1 patient showing strictures at two different sites. Sonourethrography was an accurate predictor of stricture length, retrograde urethrography underestimating the stricture length in most of the cases. Periurethral structures, including the urethral wall, corpus spongiosum, corpora cavernosa, bulb, and external urinary sphincter, were seen clearly with sonourethrography. Periurethral fibrosis was seen in 16 patients and graded as mild (n = 5), moderate (n = 2) or severe (n = 9), depending on the depth of involvement of the corpus spongiosum. Sonourethrography was unsatisfactory in the evaluation of membranous strictures, failing to visualize the proximal limit of the stricture.

Adult↗
PubMed1993

On the extracellular contribution to multiple quantum filtered 23Na NMR of perfused rat heart.

We investigated the contribution of extracellular Na+ to the multiple-quantum filtered 23Na NMR signal of perfused rat hearts to determine if the presence of shift reagent Dy(PPPi)2 and inorganic phosphate were somehow responsible for the generation of extracellular multiple quantum coherence. Neither phosphate nor shift reagent caused an increase in the total multiple-quantum filtered signal intensity or in the percent contribution from extracellular ions. On the contrary, addition of Dy(PPPi)2 actually decreased the total signal intensity from intra- and extracellular ions. Further addition of 1.5 mM Gd(PPPi)2 eliminated the extracellular contribution. These data indicate that the previously reported extracellular contribution in perfused hearts is a true contribution of extracellular ions, and not an artifact originating from their interaction with the shift reagent.

Animals↗
PubMed1993

Identification of a natural killer enhancing factor (NKEF) from human erythroid cells.

We have previously shown that RBC significantly augment NK cell-mediated cytotoxicity when added at the initiation of cytotoxicity assays. We now report that RBC cytosol contains a soluble factor that mediates a similar enhancement of NK activity when the factor is precoated on a plastic surface. We have purified this NKEF by ammonium sulfate precipitation, ion exchange chromatography, and gel filtration HPLC. While gel filtration HPLC shows that NKEF has an apparent molecular mass of between 300 and 400 kDa, SDS-PAGE analysis indicates an apparent molecular weight of 48 and 24 kDa under nonreducing and reducing conditions, respectively. Immune serum obtained from a rabbit immunized with purified NKEF blocks NKEF augmentation of NK activity. In contrast, preimmune serum fails to inhibit NKEF activity. Anti-NKEF antibody reacts with the cytosol of NK-sensitive erythroleukemic target cell K562. Western blot analysis indicates that this antibody recognizes a 24-kDa protein both in RBC and in K562. We have generated tryptic peptides from NKEF and obtained partial amino acid sequences from three of the peptides. Two of the sequences show no significant homology with any known sequences. The third sequence shows partial identity with a deduced sequence from a murine erythroleukemia-related gene. Thus, NKEF is a novel protein with unique amino acid sequence. Our results of NKEF in RBC suggest that RBC could play an important role in regulating NK function.

Amino Acid Sequence↗
PubMed1993

Radiological spectrum of endemic fluorosis: relationship with calcium intake.

Skeletal fluorosis continues to be endemic in many parts of India. Osteosclerosis and interosseous membrane calcification have long been regarded as hallmarks of this disease. Our study showed in addition a wide variety of radiological patterns: coarse trabecular pattern, axial osteosclerosis with distal osteopenia and diffuse osteopenia. Subjects with osteopenic changes had a significantly lower dietary intake of calcium than those groups having normal radiological findings, predominant osteosclerosis or coarse trabecular pattern (p < 0.001, p < 0.01, and p < 0.01 respectively). This suggests the role of calcium intake in determining the skeletal changes in endemic fluorosis.

Adolescent↗