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Biomedical subjects

D Kumar

Publications and source records attributed to D Kumar.

At least 307 records · Page 17Linked to original sources
PubMed1993

Adrenal cortical adenoma and adrenal metastasis of renal cell carcinoma: immunohistochemical and DNA ploidy analysis.

Renal cell carcinoma can have solitary adrenal metastasis years or even decades after resection of the primary tumor. The difficulty in distinguishing an adrenocortical adenoma from a solitary metastasis of a renal cell carcinoma prompted us to study 10 adrenal adenomas, 11 primary renal cell carcinomas, and three renal cell carcinomas metastatic to the adrenal gland by immunohistochemical stains and flow cytometry to determine if these techniques could help make the distinction. Immunohistochemical staining was performed for detection of cytokeratin, vimentin, and epithelial membrane antigen (EMA). Cytokeratin, vimentin, and EMA were detected in 10/11, 9/11, and 11/11 primary renal cell carcinomas, respectively, and 1/3, 2/3, and 3/3 metastatic renal cell carcinomas, respectively. All cases of adrenal adenoma were negative for the three antigens. DNA content analysis by flow cytometry showed no evidence of an abnormal DNA stemline in any of the cases except one renal cell carcinoma. We conclude that staining for EMA is consistently strongly positive in primary and metastatic renal cell carcinomas and consistently negative in adrenal adenomas, proving to be a useful distinguishing marker. Cytokeratin and vimentin, although uniformly absent in adrenal adenomas, are variably and often only weakly positive in renal cell carcinomas, and therefore of less help in making the distinction. Flow cytometry analysis has no discriminatory value in these cases.

Adenoma↗
PubMed1993

Familial tumoral calcinosis. A clinical, histopathologic, and ultrastructural study with an analysis of its calcifying process and pathogenesis.

We describe histopathologic and ultrastructural changes in tumoral calcinosis (TC) occurring in seven siblings from a single family. Tumoral calcinosis appears to be triggered by bleeding followed by aggregation of foamy histiocytes. These in turn are transformed, with participation of collagenolysis, into cystic cavities lined by osteoclast-like giant cells and histiocytes--the lesion resembling adventitious bursae. Movement and friction, forces generated from the periarticular location of the TC lesions, putatively are key to this transformation. Concomitantly, two calcifying events develop, possibly driven by concurrent hyperphosphatemia or endogenous hypervitaminosis D. One occurs on membranous fragments in antiprotease-containing large cytoplasmic vesicles within osteoclast-like giant cells and mononuclear cells lining the TC cavities; the second, in the TC locules on membranous and cellular debris derived from cavity-lining cells and erythrocytes. The TC cavities ultimately fill with calcified material, losing their synovial-like lining, become encapsulated by fibrous tissue, and ossify. Hydroxyapatite may gain entrance to capillary lumens and embolize to the lung. We conclude that TC represents a disordered reparative process that often is exaggerated because episodes of bleeding, caused by TC-induced vascular injury, provoke development of new lesions. The capricious response of TC to treatment is correlated with its morphologic features.

Adult↗
PubMed1993

Clinical implications of tumor volume measurement in stage I adenocarcinoma of the cervix.

OBJECTIVE: To evaluate the prognostic significance of three-dimensional determination of tumor size in stage I cervical adenocarcinoma. METHODS: Tumor volume was measured using hematoxylin and eosin-stained sections of cone biopsy and hysterectomy specimens from 36 patients with stage I adenocarcinoma of the cervix. The volume was then correlated with pelvic lymphatic spread and clinical outcome. RESULTS: The subjects were followed for a mean (+/- SEM) of 63 +/- 8 months. No recurrence or lymphatic seeding was encountered in the 22 tumors measuring no more than 500 mm3. Two of 25 tumors (8%) having up to 5 mm depth of stromal invasion had lymph node metastasis, one of which was 1.5 mm, compared with four of 11 (36%) in the group with deeper than 5 mm invasion (P < .02). The depth of stromal invasion predicted recurrence less significantly. Among the 25 tumors with up to 5 mm stromal invasion, two recurred, compared with three of 11 with more than 5 mm invasion (P < .1). Two women who had tumor volumes below 500 mm3 and depths of stromal invasion up to 8.5 mm were disease-free at 52 and 96 months of follow-up. On the other hand, tumors with 2.6 and 3.8 mm stromal invasion, but with volumes exceeding 500 mm3, recurred. CONCLUSION: Tumor volume is a better predictor of pelvic lymph node metastasis and recurrence than is the depth of stromal invasion in stage I cervical adenocarcinoma.

Adenocarcinoma↗
PubMed1992

Leiomyosarcoma of the orbit: diagnosis of its recurrence by fine-needle aspiration cytology.

An 8 1/2-yr-old boy with proptosis was diagnosed to have low-grade leiomyosarcoma of the orbit following lateral orbitotomy and histology of an incompletely excised intraconal mass. He received chemotherapy but had recurrence of proptosis at the age of 12 yr. Ultrasonography revealed a solid mass and its fine-needle aspiration cytology features were consistent with recurrence of leiomyosarcoma. A year later, the cytodiagnosis was confirmed by histology of the excised tumor from a second lateral orbitotomy. Masson's trichrome stain confirmed the smooth muscle nature of the neoplasm and ultrastructural features were in favor of leiomyosarcoma. The patient received intermittent chemotherapy, and is clinically free from disease at the age of 17 yr.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Noninvasive assessment of systolic and diastolic left ventricular function in patients with chronic severe anemia: a combined M-mode, two-dimensional, and Doppler echocardiographic study.

Thirty-one patients with chronic severe anemia of more than 3 months' duration (hemoglobin less than 7 gm/dl) and no underlying heart disease were studied by means of M-mode, two-dimensional, and Doppler echocardiography; an equal number of normal control subjects was also studied. There are conflicting reports regarding the influence of chronic severe anemia on systolic myocardial function, but diastolic function has not been systematically assessed. It is also uncertain whether anemia alone can cause heart failure in a structurally normal heart. We therefore performed a detailed study of echocardiographic indexes of systolic and diastolic left ventricular function in these patients. We found that patients with anemia have significantly faster heart rates and lower diastolic and mean blood pressures than normal subjects. They also have a significantly elevated cardiac output and stroke volume and larger left ventricles. Left ventricular contractility, assessed by the end-systolic stress-dimension relationship, was enhanced. There was no systematic evidence of diastolic dysfunction by Doppler assessment of mitral inflow. There was also no clinical evidence of congestive heart failure. We conclude that chronic severe anemia leads to a hyperdynamic state with systolic hyperfunction and no impairment of diastolic function. Anemia does not lead to congestive heart failure in the absence of underlying heart disease.

Adult↗
PubMed1992

Abnormal REM sleep in the irritable bowel syndrome.

Motor abnormalities of the small bowel that occur only during the waking state have been reported in the irritable bowel syndrome (IBS), suggesting that central nervous system arousal is a necessary condition for expression of the disorder and that it may reflect inappropriate brain-gut interaction. This possible relationship was explored further by synchronous polysomnography and recording of upper small bowel motility in six healthy subjects and six patients with IBS. During sleep, there was no difference in the patterns of intestinal motility between the two groups. There was no difference between the rapid eye movement (REM) latency or number of REM episodes, but the proportion of REM sleep was markedly increased (36.5% +/- 5.7% vs. 18.2% +/- 5.7%; P less than 0.01) in the IBS group, although the duration of sleep was similar (468 +/- 13 minutes in IBS vs. 444 +/- 10 minutes in controls; P greater than 0.1). Sleep apnea was detected in three of six patients with IBS but was not seen in controls. The data are consistent with the model of IBS as a disorder of brain-gut interaction.

Adult↗
PubMed1992

Dendrocyte population in cutaneous and extracutaneous Kaposi's sarcoma.

In order to investigate the hypothesis that the spindle cells of Kaposi's sarcoma originate from dendrocytes, we stained 22 cases of cutaneous and extracutaneous Kaposi's sarcoma for the presence of factor XIIIa. We selected eight lesions from the skin, five from the oral mucosa, four from gastrointestinal mucosa, three from lymph nodes, and one each from esophagus and conjunctiva for this study. The majority of cutaneous and lymph node Kaposi's sarcoma lesions had a considerable number of dendrocytes admixed with the spindle tumor cells. Of the five oral mucosal lesions only three showed a focal presence of dendrocytes. No dendrocytes were observed in the lesions biopsied from the gastrointestinal mucosa, esophagus, and conjunctiva. Our findings suggest that the proliferation of dendrocytes seen within the lesions of Kaposi's sarcoma in the skin and lymph nodes probably represents a nonspecific host response in organs where they are normally present, and it is unlikely that they constitute the neoplastic cells of Kaposi's sarcoma.

Dendritic Cells↗
PubMed1992

Transitional cell carcinoma with rhabdoid features.

We discuss the light-microscopic, immunohistochemical, electron-microscopic, and flow cytometric analysis in a case of invasive transitional cell carcinoma of the renal pelvis with rhabdoid features and glandular metaplasia. This tumor demonstrated in situ rhabdoid transformation of the transitional epithelium, which has not been described before. Electron-microscopic examination of the rhabdoid cells revealed whorled aggregates of intermediate filaments. There was also evidence of mucin-filled intracellular lumina on light and electron microscopy in both in situ and invasive components of the tumor. Our findings lend support to the view that tumors with "rhabdoid" features in adults and perhaps some children represent a heterogeneous group of neoplasms, some of which may just be unusual morphologic variants of a transitional cell carcinoma, in contrast to the distinct clinicopathologic entity of childhood renal rhabdoid tumors.

Adult↗
PubMed1992

Lymphocytic adenosine deaminase activity in typhoid fevers.

Lymphocyte adenosine deaminase (L-ADA) activity, a measure of lymphocyte activity, was estimated in 10 healthy controls and 30 patients with typhoid fever (20 uncomplicated and 10 complicated) at the time of admission, at onset of complications and weekly until recovery. Mean L-ADA activity in healthy controls was 20.49 +/- 3.62 mU/10(6) cells. In uncomplicated patients L-ADA activity was 36.33 +/- 5.09 mU/10(6) cells at time of admission, which is significantly raised as compared to controls. It remained high at the height of the fever and at defervescence. In complicated patients L-ADA activity was significantly low at admission (15.33 +/- 2.35 mU/10(6) cells) and fell further with development of complications (7.86 +/- 4.07 mU/10(6) cells). At defervescence L-ADA activity increased significantly above the control activity (31.24 +/- 5.37). Serial L-ADA activity can be of prognostic significance. A cut-off value of 24 mU/10(6) cells is suggested to predict prognosis and severity of disease. Activity below this indicates a probability of a severe, prolonged course and may help in instituting early and energetic treatment.

Adenosine Deaminase↗
PubMed1992

The 3,3'-bis-pyridinium mono-oximes as antidotes against organophosphorous intoxication.

In an attempt to develop effective antidotes against organophosphorous intoxication, three new structurally related bispyridinium mono-oximes with a 2-oxopropane bridge were synthesized. The compounds were evaluated for in-vivo therapeutic protection and cholinesterase reactivation in blood and various brain regions. In neuromuscular function studies against diisopropyl-fluorophosphate and isopropyl methylphosphonofluoridate poisoning, the oximes produced significant protection. The compounds produced marked peripheral reactivation and beneficial effects on neuromuscular transmission. The reactivation of cholinesterase in cerebral cortex by the oximes, in spite of their being quaternary salts is a notable feature.

Animals↗
PubMed1992

Cystadenoma and cystadenocarcinoma with mesenchymal stroma of the liver. Immunohistochemical analysis.

Cystadenoma with mesenchymal stroma is a rare neoplasm of the liver that occurs exclusively in young women and has a potential for malignant transformation. A light microscopic and immunohistochemical study of a case of biliary cystadenoma and another of biliary cystadenocarcinoma revealed a range of differentiation of the lining epithelial cells. The lining cells in the cystadenoma resembled the cells of the normal intrahepatic bile ducts. In contrast, the epithelial lining in the case of cystadenocarcinoma had features of intestinal mucosa, including goblet, Paneth, and endocrine cells similar to those found in other mucinous cystic neoplasms of the foregut area. The compact "ovarianlike" mesenchymal stromal cells had immunohistochemical characteristics of myofibroblasts. These are reactive contractile cells that may proliferate in response to the expanding cysts and female hormones, and they differ immunohistochemically from ovarian stromal cells.

Adult↗
PubMed1991

Glucose induces lipid peroxidation and inactivation of membrane-associated ion-transport enzymes in human erythrocytes in vivo and in vitro.

Erythrocytes of diabetic subjects (non-insulin dependent) were found to have eight- to ten-fold higher levels of endogenously formed thiobarbituric acid reactive malonyldialdehyde (MDA), thirteen-fold higher levels of phospholipid-MDA adduct, 15-20% reduced Na(+)-K(+)-ATPase activity with unchanged Ca+2-ATPase activity, as compared with the erythrocytes from normal healthy individuals. Incubation of normal erythrocytes with elevated concentrations (15-35 mM) of glucose, similar to that present in diabetic plasma, led to the increased lipid peroxidation, phospholipid-MDA adduct formation, reduction of Na(+)-K(+)-ATPase (25-50%) and Ca+2-ATPase (50%) activities. 2-doxy-glucose was 80% as effective as glucose in the lipid peroxidation and lipid adduct formation. However, other sugars, such as fructose, galactose, mannose, fucose, glucosamine and 3-O-methylmannoside, and sucrose, tested at a concentration of 35 mM, resulted in reduced (20-30%) lipid peroxidation without the formation of lipid-MDA adduct. Kinetic studies show that reductions in Na(+)-K(+)-ATPase and Ca+2-ATPase activities precede the lipid peroxidation as the enzyme inactivation occur within 30 min of incubation of erythrocytes with high concentration (15-35 mM) of glucose, while lipid peroxidation product, MDA appears at 4 hr and lipid-MDA adducts at 8 hr. The lipoxygenase pathway inhibitors, 5,8,11-eicosatriynoic acid and Baicalein (5,6,7-trihydroxyflavone), reduced the glucose-induced lipid peroxidation by 30% and MDA-lipid adduct formation by 26%. Indomethacin, a cyclooxygenase pathway inhibitor, had no discernible effect on the lipid peroxidation in erythrocytes. However, the inhibitors of lipid peroxidation, 3-phenylpyrazolidone, metyrapone, and the inhibitors of lipoxygenase pathways did not ablate the glucose-induced reduction of Na(+)-K(+)-ATPase and Ca+2-ATPase activities in erythrocytes. Erythrocytes produce 15-HETE (15-hydroxy-eicosatetraenoic acid), which is augmented by glucose. These results suggest that the formation of lipoxygenase metabolites potentiate the glucose-induced lipid peroxidation and that the inactivation of Na(+)-K(+)-ATPase and Ca+2-ATPase occurs as a result of non-covalent interaction of glucose with these enzymes.

Adenosine Triphosphatases↗
PubMed1991

Combined exposure to lead and ethanol on tissue concentration of essential metals and some biochemical indices in rat.

The effect of daily oral administration of ethanol (2.5, 5, or 10% in drinking water for 8 wk), lead (10 mg/kg, po, once daily for 8 wk), or their combination on tissue trace-metal concentration and hematopoietic and hepatic biochemical indices was investigated in male rats. Ethanol (10%) ingestion enhanced the hepatic lipid peroxidation and decreased the calcium and magnesium content of blood and liver. Coexposure to lead and ethanol (5 and 10%) produced a more pronounced elevation of blood zinc protoporphyrin (ZPP) and hepatic lipid peroxidation. Combined lead-ethanol exposure also lowered the concentration of blood and hepatic magnesium and calcium and increased the amount of lead in the blood, liver, and brain compared to a group treated with lead alone. The results suggest that chronic alcohol ingestion results in calcium and magnesium loss. However, coexposure to lead and ethanol could result in more serious depletion of calcium and magnesium, and this could be the cause of suspected synergism between alcohol consumption and lead poisoning.

5-Aminolevulinate Synthetase↗