Biomedical subjects
Publications and source records attributed to R Kumar.
A 6 year old boy with clinical and radiological features of pycnodysostosis is described. In addition to pycnodysostosis he had a myelophthisic type of anaemia suggesting an overlap with osteopetrosis.
Eighty-six randomly selected children between 6 months and 12 years of age admitted with acute unexplained encephalopathy over a one year period were examined for evidence of Japanese encephalitis. One or more indicators of the infection were present in 36 (41.8%). Viral isolation from brain tissue was possible in 2 of 12 patients and from cerebrospinal fluid in 19 out of 62 patients. Serological evidence of probable Japanese encephalitis was found in 21 out of 36 patients. Japanese encephalitis is an important cause of acute childhood encephalopathy in the Lucknow area, where it is probably endemic.
Many abnormal vertebral configurations are disease-specific and when recognized on radiographs, make correct diagnosis possible.
Vertebral expansion may be caused by both benign and malignant disease processes. Recognition of such lesions on radiographs facilitates accurate diagnosis in many cases.
We sought to determine if the high phosphorus, moderately low calcium intake typical of U.S. teenagers and young adults alters parathyroid function as it does in experimental animals. Because those animals ultimately developed osteopenia, it has been suggested that low dietary calcium to phosphorus ratios may reduce peak bone mass and increase susceptibility to osteoporotic fracture later in life. However, it is not known whether PTH secretion or action increases in response to commonly consumed phosphorus-rich, calcium-poor foods. We studied the 24-h mineral and hormonal responses of eight men and eight women, aged 18-25 yr, after 8 days of ingesting a control diet that had calcium (820 mg) and phosphorus (930 mg) contents near the recommended daily intakes, and a test diet with calcium and phosphorus contents (1660 mg phosphorus, 420 mg calcium) typical of current intakes. Both diets were made from common grocery store foods. The 24-h mean serum immunoreactive PTH levels increased in men (11%; P less than 0.006) and women (22%; P less than 0.003) during the test diet. In both sexes, the test diet significantly increased serum phosphorus, plasma 1,25-dihydroxyvitamin D, and urinary hydroxyproline and cAMP excretion; in women only it decreased serum ionized and total calcium levels. Thus, short term ingestion of a diet typifying current levels of calcium and phosphorus intake resulted in elevated serum iPTH levels and indexes of PTH action in young adults.
Human osteoblast-like cells were examined for the presence of the Ca2+-Mg2+ ATPase pump. The osteoblast-like cells had characteristic features of the osteoblast phenotype, including the presence of osteonectin, bone GLA protein, and type I collagen. The cells were able to mineralize matrix, their production of cAMP increased in response to PTH, and their alkaline phosphatase activity increased in response to 1,25-dihydroxyvitamin D3. Immunocytochemical staining of the osteoblast-like cells with a monoclonal antibody against human red cell Ca2+-Mg2+ ATPase demonstrated the presence of an epitope of the Ca2+-Mg2+ ATPase in these cells; staining of paraffin-embedded osteoblast-like cell sections demonstrated anti-Ca2+-Mg2+ ATPase staining only in cell plasma membranes. Western blot analysis of osteoblast-like cell homogenates showed that the monoclonal antibody to human erythrocyte Ca2+-Mg2+ ATPase bound to a major band at 140,000 mol wt, similar to the mol wt of known plasma membrane Ca2+-Mg2+ ATPases. The presence in the osteoblast-like cells of a Ca2+-Mg2+ ATPase similar to the human red cell calcium pump suggests that this enzyme may play a role in osteoblast intracellular calcium homeostasis.
The results of 45 MR examinations were prospectively compared with the clinical course and biopsy results in 38 renal transplant patients to determine the role of MR in evaluating allograft dysfunction. Twenty-six patients underwent allograft biopsy. In eight patients in whom the biopsy was performed more than 48 hr after MR examination and in 19 patients who did not have a biopsy, the subsequent clinical course was sufficiently diagnostic to determine the specific cause of the transplant dysfunction. Corticomedullary differentiation, graded from 0 to 3, was not helpful in separating rejection (n = 20) from acute tubular necrosis (n = 9), drug toxicity (n = 7), pyelonephritis (n = 2), or normal grafts (n = 7) because of overlap between groups (sensitivity =; 60%, specificity = 60%). In the six patients with two or more MR studies, serial changes in corticomedullary differentiation were not consistent and could not be used to diagnose rejection. When any abnormality of allograft sinus fat, size or shape, or corticomedullary differentiation was considered, the sensitivity for the diagnosis of rejection approached 80%; however, specificity was low (48%). We conclude that MR imaging is not sufficiently accurate to replace transplant biopsy and therefore has a limited role in the evaluation of transplant dysfunction.
Among 274 neonates born at the maternity services of an urban hospital in India, 36.1% of the infants shed rotavirus in feces (as detected by ELISA) by 72 h of life. The excretion rate increased to 70.3% among the 120 infants who stayed for 5 days or more at the hospital. Diarrhoeal symptoms of mild and self-limited nature were observed only in 19.2% of the rotavirus excretors, the remaining being asymptomatic. Among the 98 infants who received supplement feeds, 49% acquired rotavirus infection as against 24.7% of the 150 exclusively breast fed infants (p less than 0.001). Viral RNA in the feces of all rota positive infants showed the same electropherotype, indicating infection from a common source. The mean percentage rotavirus inhibitory activity of cord sera in the infected and non-infected infants was 50.2 +/- 21.7 and 56.6 +/- 19.2 respectively (p greater than 0.05), suggesting that cord blood antibodies do not offer significant protection against neonatal rotavirus infection.
We describe strategies for the detection of oncogenes at the single-cell level and for the positive identification of under-represented oncogenic alleles in mixed populations of normal and tumor cells. By combining the Polymerase Chain Reaction (PCR) technique with a liquid hybridization and gel retardation assay, we have been able to detect H-ras sequences in single cells, including in one fertilized mouse ovum. We also describe a modification of the PCR protocol involving the use of mismatched primers. This procedure allows for the creation of novel Restriction Fragment Length Polymorphisms (RFLP) diagnostic of specific point mutations. This experimental approach has allowed us to detect ras oncogenes in a single heterozygous cell in the presence of 10(5) normal cells.
Two cases of fibrolamellar carcinoma (FLC) of the liver reported here illustrate that this rare neoplasm is a distinct variant of the usual hepatocellular carcinoma (HCC). It occurs in younger individuals, is unrelated to liver cirrhosis and has a remarkably better prognosis due to a higher surgical resectability rate. It is sonographically hyperechoic and demonstrates angiographic and computed tomographic features of a very vascular tumor. The differential diagnosis includes focal nodular hyperplasia, hepatic adenoma, hepatocellular carcinoma and hemangioma.
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The effects of a digenetic trematode Gangatrema dehradoonense (Digenea: Opecoelidae) on the pH of small intestine in Labeo dero (Ham.) have been studied. The pH of healthy and infected intestine vary before and after feeding. A low pH has been noted in heavily infected intestine.
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In the present work we report our studies on IgG separated from the serum of lepromatous patients and non-lepromatous leprosy cases using Laser Raman Spectroscopy. Striking spectral changes in LL cases have been observed in the following special regions: (a) the amide I and III, (b) the S-S and C-S stretching (c) the skeletal bending and (d) skeletal stretching regions. These changes indicate a decrease in the amount of beta-structure and a transition towards alpha-helical conformation.