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Biomedical subjects

R Kumar

Publications and source records attributed to R Kumar.

At least 127 records · Page 7Linked to original sources
PubMed1990

Shoulder pain in hemiplegia. The role of exercise.

One of the causes for shoulder pain associated with hemiplegia is thought to be vigorous range of motion to the involved upper extremity. The objective of this study was to analyze the occurrence of pain in patients treated with one of the three exercise programs commonly used in the rehabilitation of hemiplegia: 1) range of motion by the therapist, 2) skate board and 3) overhead pulley. Of the 48 hemiplegic patients evaluated, 28 were assigned to one of the three exercise groups. Comparing the number of patients who developed pain in each group, there was a significant difference, with 8% of the patients in the range of motion by the therapist group, 12% of the patients in the skate board group and 62% of the patients in the overhead pulley group developing pain (chi 2 = 8.44) (P = 0.014). The three groups did not differ in the side of involvement (P = 0.57), extent of hemiplegia (P = 0.25) or presence of subluxation (P = 0.84). Use of overhead pulley has the highest risk of developing shoulder pain and should be avoided during rehabilitation of stroke patients.

Adult↗
PubMed1990

Detection of colonization factor antigen I-positive enterotoxigenic Escherichia coli with a cloned polynucleotide probe.

We compared a new colony hybridization assay with an established enzyme-linked immunosorbent assay for detection of enterotoxigenic Escherichia coli (ETEC) expressing colonization factor antigen I (CFA/I). The tests were applied to 135 human ETEC strains. Of these isolates, 30 had previously been characterized for CFAs. A strain harboring the plasmid vector of the polynucleotide gene probe, nine non-ETEC strains from healthy infants, and eight ETEC strains of animal origin were included for further evaluation of probe specificity. The two assays showed a high level of concordance in the specific detection of ETEC strains expressing CFA/I. A total of 24 strains tested positive in the CFA/I hybridization assay, while 23 of those strains were positive in the CFA/I enzyme-linked immunosorbent assay. The single discrepant result could be explained by the loss of a regulatory gene. The strain harboring the plasmid vector of the probe, the non-ETEC E. coli strains, and the ETEC strains of animal origin were all negative in the CFA/I probe assay.

Animals↗
PubMed1990

Sequence of the circle junction of human immunodeficiency virus type 1: implications for reverse transcription and integration.

The sequence of the LTR-LTR circle junction of human immunodeficiency virus type 1 (HIV-1) was determined. The circle junction sequences were amplified by the polymerase chain reaction and cloned into M13 sequencing vectors. The circle junction contains 4 base pairs that are not present in the integrated provirus. We show that reverse transcription in HIV-1 initiates with the addition of a dC to the tRNA primer, suggesting that the tRNA used to initiate reverse transcription ends with the consensus CCA triplet. This indicates that the source of one of the four bases in the circle junction is probably the terminal A of the tRNA primer used to initiate reverse transcription. We propose that, in HIV-1, removal of the tRNA primer by RNase H cleavage shows an unusual specificity such that cleavage occurs between the terminal rA and the adjacent rC of the tRNA primer. These data also imply that the HIV-1 integration protein removes two bases from each end of the linear viral DNA during integration as has been described for other well-studied retroviruses.

Base Sequence↗
PubMed1990

Density-dependent nerve growth factor regulation of Gs-alpha RNA in pheochromocytoma 12 cells.

Nerve growth factor (NGF) affects levels of the alpha subunit of the stimulatory G protein (Gs-alpha) in pheochromocytoma 12 cells in a bidirectional, density-dependent manner. Cells grown at high density responded to NGF treatment with increased levels of Gs-alpha mRNA and protein. Conversely, in cells grown in low-density cultures, levels of this mRNA were lowered by NGF treatment.

Adrenal Gland Neoplasms↗
PubMed1990

Human trk oncogenes activated by point mutation, in-frame deletion, and duplication of the tyrosine kinase domain.

Malignant activation of the human trk proto-oncogene, a member of the tyrosine protein kinase receptor family, has been implicated in the development of certain human cancers, including colon and thyroid papillary carcinomas. trk oncogenes have also been identified in cultured cells transfected with various DNAs. In this study, we report the characterization of three in vitro-generated trk oncogenes, trk2, trk4, and trk5 (R. Oskam, F. Coulier, M. Ernst, D. Martin-Zanca, and M. Barbacid, Proc. Natl. Acad. Sci. USA 85:2964-2968, 1988), in an effort to understand the spectrum of mutational events that can activate the human trk gene. Nucleotide sequence analysis of cDNA clones of trk2 and trk4 revealed that these oncogenes were generated by a head-to-tail arrangement of two trk tyrosine protein kinase domains connected by a purine-rich region. These oncogenes code for cytoplasmic molecules of 67,000 (p67trk2) and 69,000 (p69trk4) daltons. In contrast, the product of the trk5 oncogene, gp95trk5, is a cell surface glycoprotein of 95,000 daltons. This oncogene was generated by a 153-base-pair in-frame deletion within sequences coding for the extracellular domain of the trk receptor. This activating deletion encompasses a triplet coding for one of the nine cysteine residues that the trk receptor shares with the product of the highly related trkB tyrosine protein kinase gene. Introduction of a single point mutation (TGT----AGT) in this codon resulted in a novel trk oncogene whose product, gp140S345, differs from the nontransforming trk proto-oncogene receptor in a single amino acid residue, Ser-345 instead of Cys-345. These results illustrate that multiple molecular mechanisms, including point mutation, internal deletion, and kinase domain duplication, can result in the malignant activation of the human trk proto-oncogene.

Amino Acid Sequence↗
PubMed1990

Virological investigations of acute encephalopathy in India.

A total of 740 consecutive children aged between 6 months and 12 years who presented with acute encephalopathic illnesses during a three year period were assessed both clinically and by laboratory investigations. Cerebrospinal fluid was examined for the presence of cells or other abnormal substances, and any organisms were cultured. Blood examination included white cell count and estimations of haemoglobin, urea, glucose, and electrolyte concentrations and serum alanine aminotransferase and aspartate aminotransferase. A firm diagnosis was established in 278 patients (38%). Pyogenic meningitis (n = 134), measles encephalopathy (n = 38), and electrolyte imbalance (n = 23) were important causes in this group, cerebral malaria (n = 4) was uncommon and there were no cases of Reye's syndrome. The diagnoses of the remaining 462 were combined under the heading 'acute unexplained encephalopathy'. Altogether 394 of the 462 patients underwent virological investigations for arboviruses and 92 (23%) had one or more indicators of Japanese encephalitis. No other arboviruses could be isolated. Throat swabs from 187 patients with acute unexplained encephalopathy were studied on monkey kidney tissue cell lines of which 14 were positive (8%). These were identified as adenovirus, parainfluenza, influenza, poliomyelitis, Coxsackie, and echovirus; in two cases the virus was untypable. Japanese encephalitis is an important cause of acute childhood encephalopathy in this region. Clinical features of the illness may be mimicked by several disorders which require specific treatment. Thirty four of the 92 died (37%).

Acute Disease↗
PubMed1990

Fibrous lesions of bones.

A large variety of benign and malignant fibrous lesions occur in the skeleton. Many fibrous bone lesions have characteristic features on plain radiographs and are easy to diagnose; others may pose significant difficulty. Most often, an osteolytic defect is seen associated with a fibrous lesion in the affected bone, although a mixed and sclerotic fibrous bone lesion is not unusual. Many benign fibrous bone lesions are asymptomatic; others become clinically apparent because of associated pathologic fracture or deformity of the involved bone. Malignant fibrous lesions tend to be aggressive, with focal bone destruction and adjacent soft-tissue involvement. The authors describe many fibrous bone lesions with their salient clinical and radiographic features.

Bone Diseases↗
PubMed1990

Primary Ewing sarcoma of rib.

Ewing sarcoma is a relatively common, highly malignant bone tumor that typically occurs in adolescents and young adults aged 10-25 years. Our archives contain 328 cases of histologically proved and radiologically correlated Ewing sarcoma collected in consultation over 40 years. From this series, we identified 34 lesions (10%) arising in ribs. Radiographically, the affected rib was predominantly lytic in most (82%) cases, but mixed lytic-sclerotic (9%) and even predominantly sclerotic (9%) patterns were also encountered. The affected rib was "expanded" in 35% of cases, although the contour change was usually mild. Abnormalities of the affected ipsilateral hemithorax varied from subtle, isolated rib involvement to solitary rib involvement accompanied by complete opacification of the hemithorax. We describe the spectrum of radiologic findings of primary Ewing sarcoma of rib, augmented where appropriate by accompanying pathologic material.

Adolescent↗
PubMed1990

Physiology and biochemistry of vitamin D-dependent calcium binding proteins.

The vitamin D-dependent calcium binding proteins (calbindins) are members of the troponin-C superfamily of proteins that occur in a number of calcium-transporting tissues such as the intestine, the distal tubule of the kidney, and the placenta. They are also present in other tissues such as the brain, peripheral nervous system, pancreas, parathyroid gland, and bone. In some tissues, such as the adult brain, the proteins occur in the absence of the vitamin. The proteins bind calcium in "EF" hand structures and are "calcium-sensitive" in that they undergo a conformational change on binding calcium. They appear to enhance transcellular calcium transport and are frequently present in tissues that contain the plasma membrane calcium pump.

Amino Acid Sequence↗
PubMed1990

Altered maternal thyroid function: fetal and neonatal myocardial metabolism.

The influence of the maternal thyroid status on the fetal and neonatal myocardial protein, carbohydrate and lipid metabolism was studied in rats. The neonates born of hypothyroid mothers could not survive beyond 8 days after birth. The offsprings born of hypothyroid mothers showed growth retardation, decreased level of heart mitochondrial protein, reduced myocardial free fatty acid (FFA) oxidation at birth and afterwards, low glucose oxidation by the heart at later fetal stages, and afterwards, despite low heart glycogen reserve, glucose oxidation was high. The offsprings born of hyperthyroid mothers showed stimulation in overall growth, increased myocardial FFA oxidation and increased 14C-glucose incorporation into glycogen as well as increased myocardial glucose oxidation during fetal stages. Results indicate that maternal thyroid hormones play an important role in the metabolic control of fetuses and neonates.

Animals↗
PubMed1990

Persistently elevated parathyroid hormone secretion and action in young women after four weeks of ingesting high phosphorus, low calcium diets.

In an earlier 8-day study, we showed increased immunoreactive PTH (iPTH) levels in young adults fed high phosphorus (P), low calcium (Ca) diets assembled from common grocery foods, a dietary pattern characteristic of teens and young adults. Because animals fed high P, low Ca diets developed secondary hyperparathyroidism and, ultimately, osteopenia, perhaps the typical teen diet may reduce peak bone mass and contribute to osteoporotic fracture later in life. To determine if the elevation in iPTH levels and action persists with chronic intake of this typical diet, we studied the 24-h mineral and hormone responses of 15 young women (18-25 yr of age) to either high P, low Ca or control diets. Each subject served as her own control, first consuming a basal diet (800 mg Ca, 900 mg P) for 28 days; 10 women were then switched to the high P, low Ca test diet (400 mg Ca, 1700 mg P) for 28 days, while the remaining 5 women in the control group continued eating the basal diet. On days 28 and 56, all subjects were studied as inpatients for 24 h, with blood drawn every 4 h and collection of fasting and 24-h urine. Serum iPTH (midregion) and serum intact PTH (2-site immunoradiometric assay) increased significantly [maximal increases of 26% (P less than 0.002) and 36% (P less than 0.004), respectively] after 4 weeks of consuming the test diet, and there was no change in the control group. In contrast to our 8-day study, plasma levels of 1,25-dihydroxyvitamin D did not change in either group. Our findings suggest that this common dietary pattern in young adult women causes persistent alterations in calcium-regulating hormones that could be unfavorable to achieving maximal positive bone balance.

Adult↗
PubMed1990

Vitamin D metabolism and mechanisms of calcium transport.

Vitamin D3 undergoes sequential hydroxylations in the liver and kidney to form 1,25-dihydroxyvitamin D3, the biologically active form of the vitamin. 1,25-dihydroxyvitamin D3 is metabolized by several processes in various target tissues that decrease the biological activity of the sterol. In addition, 1,25-dihydroxyvitamin D3 is excreted in the bile as polar metabolites, such as glucuronides and, possibly sulfates and neutral polar steroids. These compounds undergo an enterohepatic recirculation in both man and experimental animals. 1,25-dihydroxyvitamin D3 increases the absorption of calcium in the intestine and the reabsorption of calcium in the kidney. It induces the synthesis of several proteins, the most notable of which is calcium binding protein that is thought to play a role in the absorption of calcium. The vitamin D-dependent calcium binding proteins and the calcium-magnesium ATPase calcium pump are co-localized in several tissues that play a role in the absorption of calcium.

Animals↗
PubMed1990

Parosteal osteogenic sarcoma arising in cranial bones: clinical and radiologic features in eight patients.

Parosteal osteogenic sarcoma is a distinct surface bone tumor with a better prognosis than conventional osteogenic sarcoma. We studied eight histologically proved cases of cranial parosteal osteogenic sarcoma. The tumors were identical in histologic appearance to parosteal osteosarcoma arising in long bones. Clinically, the tumor presented as a hard, painless, nodular scalp mass. The prevalence in women outnumbered that in men by 3:1, with most cases occurring between the second and third decades of life. Plain radiographs showed a rounded, sessile bone growth of variable size arising from the outer table of the skull. The tumor was heavily ossified centrally with variable margins and, at times, with radiating bony spicules at the periphery. No satellite bone nodules were noted in adjacent soft tissues. In three cases a fine radiolucent cleft was demonstrated between the tumor and the underlying outer table on the tangential radiographs or CT. After en bloc resection of the tumor, follow-ups for 20 years in one patient and 1 year in two patients showed no recurrence. Parosteal osteosarcoma of the skull is a rare low-grade tumor that usually arises from the outer table of the skull and has distinctive radiologic features that should distinguish it from other exophytic cranial bone neoplasms.

Adolescent↗
PubMed1990

Comparative study of out-reach immunization strategies in rural area.

Efficiency of out-reach immunization strategies operationalised in a rural area of district Ambala (Haryana) was evaluated. Till year 1984-85 immunization delivery was 'sporadic'. Annual cluster immunization campaigns were conducted during 1985-86 and 1986-87. This comprised of delivery of oral polio vaccine (OPV) and/or measles once in a year to all eligible children, other vaccine continued to be delivered by health workers during routine beats. Regular immunization sessions were undertaken in 1987-88 and 1988-89. All the vaccines were delivered on 4 fixed days (one day per week) of each month, covering village at least once a month. Significant increase in immunization coverage was observed after cluster campaigns. OPV increased from 46.5 to 73.6%, DPT from 49.1 to 75.5%, BCG from 48.7 to 72.2%, measles from 8.6 to 45.8% and tetanus toxoid (TT) for pregnant women (PW) from 41.8 to 65.3%. Under regular programme the coverage levels were maintained at OPV 79.4%, DPT 78.2%, BCG 70.6%, measles 48% and TT (PW) 76.2%. Regular out-reach immunization strategy was found to be better than cluster campaigns as it was 'regular' and high coverage level could be maintained.

Child, Preschool↗
PubMed1990

Activation of H-ras oncogenes in preneoplastic mouse mammary tissues.

The mammary hyperplastic outgrowth (HOG) line C4, resulted from serial transplantation of a hyperplastic alveolar nodule which arose in a dimethylbenz(a)anthracene (DMBA) treated mouse. The immortalized C4 outgrowth line, on transplantation into syngeneic mice, develops as preneoplastic, hyperplastic outgrowths and subsequently into malignant carcinomas after a long latent period (greater than 6 months). Treatment of mice carrying C4 HOG transplants with DMBA resulted in a reduced latent period for tumor development (less than 3 months) and an increased tumor incidence. DNA's from C4 HOGs and mammary carcinomas of untreated as well as DMBA-treated mice were analyzed for the presence of oncogenes by the NIH3T3 focus forming assay. Transforming H-ras genes were detected in two of 6 preneoplastic HOGs and 10 of 12 carcinomas from DMBA-treated mice. DNAs from neither the HOGs nor the tumors from untreated mice were positive in this assay. The H-ras locus was then directly examined in the 61st codon by in vitro amplification of each of the tissue DNAs using PCR. The location of the activating mutation was determined by hybridization of amplified DNA to mixed sequence oligonucleotide probes. The specific nature of the mutation was defined by RFLPs using XbaI, TaqI and Sau96I restriction enzymes. Six of the H-ras oncogenes in DMBA-promoted tumors were activated by commonly observed A to T transversions at the 61st codon, while five (including an additional tumor with H-ras oncogene revealed by PCR analysis) contained novel A to G transitions. The H-ras oncogene in one DMBA-treated HOG sample was activated by A to T while the second contained an A to G mutations, representative of both modes of mutational activation involved in this model of mammary tumorigenesis. In summary, DMBA-induced point mutated H-ras oncogenes appear to potentiate the progression of hyperplastic outgrowths (HOG) to mammary carcinomas.

9,10-Dimethyl-1,2-benzanthracene↗