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Biomedical subjects

R V Kumar

Publications and source records attributed to R V Kumar.

44 records · Page 3Linked to original sources
PubMed1987

Pharmacokinetics of methotrexate in Indian children and its relationship to nutritional status.

Any significant change in the pharmacokinetics of an anticancer drug would have a bearing on its therapeutic efficacy and toxicity. Nutritional deficiencies have been shown to affect the pharmacokinetics of a drug. Since malnutrition and undernutrition are widely prevalent in India, the effect of initial nutritional status on the overall kinetics of methotrexate (MTX) administered to cancer patients appeared to be of practical importance. A study of 6 Indian children with malignancies was made to examine the pharmacokinetics of low dose MTX and its relationship to the nutritional status. The results indicate that the relative weight correlates well with the anthropometric parameters, nutritional parameters and dietary intake and may be used as a marker of nutritional status.

Adolescent↗
PubMedDate not supplied

Genetics of a new male-sterility locus in pigeonpea (Cajanus cajan [L.] Millsp.).

A natural male-sterile mutant was found in the population of a short-duration pigeonpea (Cajanus cajan[L.] Millsp.) cultivar ICPL 85010. This mutant is characterized by light yellow anthers of reduced size that are devoid of pollen grains. This mutant was crossed with two pigeonpea cultivars to study its inheritance. The F1, F2, and test cross data of the two crosses suggested that this male sterility trait is genetic in origin and is controlled by a single recessivegene. The F1 (mutant x ICPL 85010) plants were crossed with translucent (ms1) and arrowhead type (ms2) genetic male steriles reported earlier to study their allelic relationships. Segregation in the three-way cross F1 and F2 populations revealed that the mutant male-sterile gene was nonallelic to ms1 and ms2 loci and it is designated ms3. The new male sterility sources in pigeonpea will help in producing high-yielding hybrids and populations in diverse phenological groups.

Alleles↗
PubMedDate not supplied

Diagnosis of clival chordoma by fine needle aspiration of an oropharyngeal mass. A case report.

A sphenooccipital chordoma presenting as a large nasopharyngeal mass extending into the oropharynx was diagnosed by transoral fine needle aspiration biopsy (FNAB) and confirmed by subsequent histologic studies. The cytologic features of chordoma are presented, and the diagnostic utility of FNAB in evaluating similar lesions in the head and neck region is discussed.

Adult↗
PubMedDate not supplied

Fine needle aspiration cytology of chondroblastoma and chondromyxoid fibroma. A report of two cases.

The fine needle aspiration cytology in two cases of chondroblastoma and chondromyxoid fibroma are described. The diagnosis of chondroblastoma was made on a recurrent tumor of which the histopathology was known, whereas chondromyxoid fibroma was diagnosed initially on fine needle aspiration cytology. The radiologic appearances and differential diagnoses of these chondroid neoplasms are discussed.

Adolescent↗
PubMedDate not supplied

Aspiration biopsy cytology of primary bone lesions.

Fine needle aspiration cytology of 79 primary bone lesions was done, and the clinical and radiologic features were correlated with cytopathology. Seventy-four of these cases were primary malignant bone tumors, two cases each were tumor-like or inflammatory lesions, and one case was a benign bone tumor. Osteosarcoma (37.7%) and Ewing's sarcoma (15.6%) were the most common primary lesions. Correlation with histopathology was possible in 37 cases, and an accuracy rate of 94.1% was achieved. There was an 89% correlation between radiologic and cytologic diagnoses. It was concluded that in this oncology center a working diagnosis based on cytology was possible in almost all cases after correlating with the radiologic findings. However, when there was a discrepancy between the clinical, radiologic and cytologic diagnoses, an open biopsy was mandatory.

Adolescent↗
PubMedDate not supplied

Improved blood substitute: evaluation of its effects on human endothelial cells.

The authors have previously documented that appropriate chemical and pharmacologic modification of the hemoglobin molecule are required to attenuate certain pathophysiologic reactions of the reticuloendothelium. The current study further investigates the molecular responses of human coronary artery endothelial cells to a high concentration (0.4 mmol) of 1) unmodified bovine hemoglobin; and 2) an improved blood substitute that comprises hemoglobin cross-linked intramolecularly with o-adenosine triphosphate and intermolecularly with o-adenosine, and conjugated with reduced glutathione. In this study, the scavenging effect of hemoglobins toward nitric oxide (NO) was evaluated by the measurement of nitrite (NO2-) and nitrate (NO3-) formation. The pro-oxidant effect of hemoglobin on endothelial cells was examined by the measurement of intracellular reduced glutathione, and by monitoring the formation of lipid hydroperoxides and 8-iso prostaglandin F2alpha, a novel potent vasoconstrictor, which is produced by a noncyclooxygenase mechanism involving free radical catalyzed peroxidation of arachidonic acid. The inflammatory reactions of endothelial cells were evaluated by the expression of the adhesion molecule, intracellular adhesion molecule-1, and the activation of nuclear transcription factor, nuclear factor kappaB. In additional, endothelial cell responses were investigated by analysis of intracellular ionized calcium concentrations. Results indicate that unmodified hemoglobin in a concentration of 0.4 mmol/L can aggravate endothelial cell oxidative and inflammatory responses. This hemoglobin produced a significant (p < 0.01) depletion of reduced glutathione, acceleration of lipid peroxidation, and a greater influx of Ca2+. The formation of 8-iso prostaglandin F2alpha increased compared with the control cells (p < 0.01). Unmodified hemoglobin was found to be a potent scavenger of NO, great activator of nuclear factor kappaB, and a stimulator of intracellular adhesion molecule-1 expression. Contrarily, the improved blood substitute did not appear to induce oxidative stress nor to increase the intracellular Ca2+. The concentration of 8-iso prostaglandin F2alpha was similar to that in the control cells, whereas the formation of NO2-/NO3- was much lower (p < 0.05) than in the unmodified hemoglobin group. The effect of an improved blood substitute can be linked with the anti-inflammatory and cytoprotective properties of adenosine, which is used as a cross-linker and surface modifier, and the type of the chemical modification procedure that lowers hemoglobin pro-oxidant potential.

Arachidonic Acid↗