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Biomedical subjects

M Kumar

Publications and source records attributed to M Kumar.

At least 343 records · Page 19Linked to original sources
PubMed1984

Carbohydrate-specific antibodies in normal human sera. I. Characterization of specificity for beta-D-glucose.

A glucose-dependent hemagglutinin, present in the serum of an apparently healthy donor, is shown to be a polyclonal IgM immunoglobulin with specificity for beta-D-glucopyranose configuration. The antibody did not agglutinate erythrocytes coated with hexoses differing from glucose at C2, C3, or C4 positions or lacking the primary alcohol group at C6 position. The hemagglutination reaction, quantitated in a continuous flow system, was inhibited by the addition of 6-deoxyglucose, 5-thioglucose, 2-deoxyglucose, 2-aminoglucose or 3-0 methylglucose. D-glucose, in beta- but not in alpha-configuration, attached by a glycosidic bond to another glucose or to an aglycone, was also inhibitory. A cross-reactivity was demonstrated between glucose and 6-deoxyglucose by antibody absorption and elution techniques. The donor's serum contained independent antibodies that reacted with erythrocytes coated with melibiose, gentiobiose, cellobiose, or N-acetylmannosamine. Further investigation revealed that antibodies are present in sera of all normal adults against erythrocytes coated with melibiose and N-acetylmannosamine and with high frequency against erythrocytes coated with gentiobiose, L-rhamnose, cellobiose, D-mannose, lactose, or D-galactose.

Antibody Specificity↗
PubMed1984

Changes in blood cellular components, serum proteins and serum enzyme activities in pigs naturally infected with Cysticercus tenuicollis.

A study was made of blood cellular components, serum proteins and serum enzymes in 48 pigs naturally infected with Cysticercus tenuicollis. Twenty-five healthy pigs were studied for comparison. Affected animals showed a reduction in total erythrocyte count, packed cell volume and haemoglobin content and an increase in mean corpuscular volume and total leucocyte count. Significantly higher activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and isocitric dehydrogenase serum enzymes were recorded in all affected pigs. Total protein, albumin and globulin values of affected pigs remained unchanged when compared with healthy controls.

Alanine Transaminase↗
PubMed1983

Inhibition of cold insolubility of an IgA cryoglobulin by decanedicarboxylic acid and related compounds.

Cold insolubility of a serum IgA cryoimmunoglobulin was found to be inhibited by the addition of 1.5 mM sodium decanedicarboxylate in vitro. The patient with the cryoglobulin had advanced multiple myeloma complicated by severe hyperviscosity that caused lethargy and episodic loss of consciousness. Decanedicarboxylic acid administered orally resulted in transient relief of symptoms and the loss of cryoprecipitability of the paraprotein. Further in vitro studies revealed that sodium salts of long-chain monocarboxylic acids with a minimum of eight carbons, and dicarboxylic acids with a minimum of 12 carbons inhibited cryoprecipitation. Salts of short-chain carboxylic acids, by contrast, enhanced cryoprecipitation. Sodium phenolate and sodium salts of benzoic acid, 2,4-DNP, phenylpropionic acid, and salicylic acid were also inhibitory. These latter compounds, which have a ring structure, did not cause precipitation at any concentration. It was demonstrated that the presence of a free carboxylic group was required for these activities; conversion of carboxylic acid to amide resulted in the loss of both the inhibitory and cryoprecipitation-enhancing effects. Normal plasma, or plasma from five other patients who had IgG, IgM, or mixed-type cryoglobulinemia, were not affected by any of these compounds. It is suggested that in selected cases of hyperviscosity syndrome associated with cryoglobulinemia, some of these compounds, especially monocarboxylic acids with appropriate chain lengths, or those with a ring structure, may have therapeutic applications.

Acetamides↗
PubMed1983

Limb salvage procedures for children with osteosarcoma: an alternative to amputation.

Amputation remains the standard surgical management for patients with osteosarcoma. However, in carefully selected patients, eradication of the primary tumor can be achieved by En-Bloc resection of the affected bone preserving both anatomical and functional status. Our criteria for limb salvage procedures are that patients must: (1) be age 12 years or older, (2) have no angiographic or clinical evidence of neurovascular involvement, (3) have low-grade osteosarcoma and/or good response to preoperative chemotherapy, and (4) be compliant. Between November 1980 and October 1982, 32 patients with osteosarcoma of an extremity were seen. Eight patients ranging in age from 13 to 21 years underwent limb salvage procedures. Five of these had Tikhoff-Linberg procedures for upper extremity lesions, two had En-Bloc resections for distal femur lesions, and one patient had a segmental arthrodesis for a distal tibial lesion. Of these eight patients, two had low-grade parosteal osteosarcoma. Follow-up ranged from 10 to 28 months (median 16 months). The two patients with parosteal osteosarcoma received no further therapy, while the other six patients received multiple agent chemotherapy. One patient died at 18 months with bilateral pulmonary disease. None have had local recurrences. Two of the eight patients had minor skin necrosis, requiring revision subsequently. Three patients have had transient nerve palsy. All have had good functional results. With careful selection of patients by rigid criteria, limb salvage procedures can be a viable alternative to amputation.

Adolescent↗
PubMed1983

Surgicopathologic staging of neuroblastoma: prognostic significance of regional lymph node metastases.

Of 254 children with neuroblastoma treated at St. Jude Children's Research Hospital, 102 (40%) had clinically localized tumors. Using a surgicopathologic staging system, 66 of these 102 children had localized tumor and 36 had tumor dissemination to regional lymph nodes. Survival of these two groups has been markedly different; 57 of 66 (87%) with localized tumor survive, compared with 11 of 35 (33%) with node dissemination, five of whom are less than two years from diagnosis. Our data indicate that the prognosis for children with neuroblastoma metastatic only to regional lymph nodes is no different from that of patients of similar age with widely disseminated tumor.

Age Factors↗
PubMed1983

The response of Ewing's sarcoma to sequential cyclophosphamide and adriamycin induction therapy.

Twenty-four consecutive patients with Ewing's sarcoma were treated in a protocol designed to deliver induction chemotherapy with postinduction surgical-pathologic evaluation of the primary tumor site. This was followed by delayed radiotherapy, the dose and port of which was dependent on the response to induction chemotherapy. All patients received 5 courses of sequential cyclophosphamide and adriamycin during the 3-mo induction period. Nineteen of 23 evaluable patients had no gross residual tumor following this therapy. Of the remaining 4, 2 had complete surgical excision of residual gross disease. Of the 22 patients who were free of gross tumor following induction chemotherapy and surgery, 5 received no radiotherapy, 16 received moderate-dose limited port radiotherapy (3000-3500 R), and 1 received high-dose limited port radiotherapy (5000 R). All 14 patients with localized disease attained remission and are surviving 9-41+ mo (median 21+) with 2 local recurrences occurring after 10 and 33 mo of remission. Of the 10 patients presenting with metastatic disease, 8 attained complete remission with 4 of the 8 remaining disease-free 12-34+ mo from diagnosis. This study indicates that Ewing's sarcoma is very sensitive to moderate-dose 2 drug chemotherapy of low toxicity and that it is possible to delay radiotherapy and any extensive surgical procedure until remission is induced.

Adolescent↗
PubMed1983

Role of autoimmunity in retinitis pigmentosa.

Twenty-five cases of retinitis pigmentosa were investigated to assess the cell-mediated immunity and for evidence of autoimmunity by measuring peripheral blood T-cell rosette count, cutaneous DTH response to recall antigens (Candida and purified protein derivative [PPD]), and 2:4 dinitrochlorobenzene (DNCB) and antiretinal antibody by tanned red cell hemagglutination technique. It was observed that cell-mediated immunity was significantly depressed, and antiretinal antibody was found in 60% of the cases, which correlated with the duration and severity of the disease. We conclude that although retinitis pigmentosa is genetically determined, patients develop autoimmunity against retinal tissue due to suppression of cell-mediated immunity. Association of rheumatoid factor in 8% of the cases further confirms the loss of homeostatic control owing to suppressed cell-mediated immunity.

Antigen-Antibody Reactions↗
PubMed1982

Concentration of triglyceride and cholesterol in lipoprotein fractions in maternal and cord blood samples.

Blood samples from 100 normal mothers at delivery and from umbilical cord blood were analysed for total cholesterol, triglyceride and cholesterol in high density lipoprotein. Cholesterol in very low density lipoprotein and low density lipoprotein were calculated by formula. Electrophoresis in agarose gel was performed on serum. There was no significant difference in the values in cord blood of girls and boys. There was no significant correlation between maternal and cord blood values. Pre-beta band was present in all cord blood samples. The electrophoretic mobility of pre-beta in cord blood is the same as that in adult blood. Faster mobility of alpha is observed in 26% of the cord blood samples.

Cholesterol↗
PubMed1982

Stimulation of endogenous catecholamine release by theophylline: a proposed additional mechanism of action for theophylline effects.

Therapeutic response to theophylline in asthma is generally attributed to its effect in increasing intracellular 3',5' cyclic adenosine monophosphate (cAMP) by competitive inhibition of cAMP phosphodiesterase. However, because of discrepancies between therapeutic serum theophylline concentration achieved clinically and those required for in vitro phosphodiesterase inhibition, we explored the possibility that theophylline may act through adrenomedullary secretion of catecholamines. Five healthy, nonasthmatic male and female adults were studied with a double-blind, randomized, crossover protocol. Theophylline (5 mg/kg) and placebo were administered in a capsule dosage form. Plasma catecholamines epinephrine (E), norepinephrine (NE), and dopamine (DA) were measured by a radioenzymatic assay at baseline and after administration of theophylline at 1, 2, and 3 hr. Significant differences between theophylline- and placebo-treated groups (p less than 0.05) were seen at 3 hr for mean percentage increase over baseline with E (120% +/- 25.3%) and NE (48.02% +/- 17.94%) after theophylline therapy (mean peak level 7.2 +/- 0.48 micrograms/ml). Epinephrine plasma concentration was significantly greater (p less than 0.001) at 3 hr compared with baseline (105 +/- 16 vs 56 +/- 18 pg/ml), while NE (448 +/- 52 vs 320 +/- 36 pg/ml) did not attain significance (p = 0.136). A significant correlation (p less than 0.05) was found between the percentage increase over basal for E (r = 0.58) and NE (r = 0.66) and serum theophylline levels. DA was not significantly increased at any time period. Thus theophylline in clinically relevant concentration appears to stimulate adrenomedullary secretion of catecholamine. Whether this is an important mechanism of action in asthma or explains some side effects of theophylline remains to be determined.

Adrenal Medulla↗