PubMed Health⌕ Search

Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 91 records · Page 5Linked to original sources
PubMed1992

Protection of mouse oesophageal mucosa against gamma rays injury.

The alterations in the oesophageal epithelium were studied in mice after a single whole-body exposure to 7.5 Gy of Co-60 gamma rays in presence or absence of 2-mercaptopropionyl glycine. The epithelium showed an increase in the thickness which reached a maximum on the third day and then decreased gradually up to seventh day after irradiation in the non-drug treated group. In the 2-mercaptopropionyl glycine treated animals the epithelial thickness remained in the normal range except on the day 7 when it was significantly lower than normal. The total cell population registered a steady decline from one to seven days post-irradiation in both groups, but the number of cells was more in the 2-mercaptopropionyl glycine treated group. The number of pycnotic nuclei showed an inverse relationship to the total cell population, it increased continuously up to seven days in both the protected and non-protected groups. However, pycnotic nuclei were significantly lower in the protected group on days 3, 5 and 7 in non-protected group.

Animals↗
PubMed1992

An out-break of epidemic dropsy in the Barabanki District of Uttar Pradesh, India: a limited trial for the scope of antioxidants in the management of symptoms.

An attempt was made to explore the scope of the bio-antioxidants in the management of symptoms of epidemic dropsy caused by argemone alkaloids, sanguinarine and dihydrosanguinarine. The study was performed on 24 randomly selected epidemic dropsy cases who consumed argemone contaminated mustard oil. On examination the cases revealed characteristic pitting edema over limbs (95.8%) accompanied by tenderness (79.2%) and diffuse erythema (95.8%). Tachycardia was present in 1/3 of the examined cases while elevated jugular venous pressure was seen in over 40% of the cases. In two of the cases, reddish-purplish blotches over lower limbs, not raised and which blanched on pressure, was an unusual feature. Chest X-ray revealed pulmonary congestion in 5 cases. ECG performed in 3 cases with severe breathlessness, showed non-specific ST-T changes most marked in L2,L3, avF and V2-V6 which reversed on recovery. Treatment with a combination of antioxidants, riboflavin and tocopherol showed improvement in pain in lower limbs (75%), edema (83.3%) and erythema (66.6%).

Adolescent↗
PubMed1992

Sequences within the R region of the long terminal repeat activate basal transcription from the HIV-1 promoter.

The importance of the R region in basal human immunodeficiency virus type 1 (HIV-1) transcription was addressed by comparing a panel of HIV-1 R region mutants using in vitro and in vivo assays. Using deletion, base substitution mutants, and compensatory mutants, the precise R region sequences essential for basal HIV-1 promoter activity in vitro were mapped to sequences between +17 to +21. Within this regulatory domain, nucleotides +19 and +21 appear to be critical. The effect of these mutations on steady state RNA levels in transfected cells has been analyzed by S1 nuclease protection assay using uniformly labeled probes. Two main conclusions may be drawn from these studies. First, HIV-1 basal transcription is abundant, with the majority of correctly initiated transcripts truncated between sequences +57 to +70. Second, analysis of the compensatory mutants indicates the secondary structure of the nascent R region RNA is not an obligate requirement for the production of the truncated transcripts. Mutations in R region primary sequence that selectively abolish the production of the truncated transcripts in vivo also exhibit reduced promoter activity in vitro. The appearance of high levels of truncated transcripts raise the interesting possibility that-similar to c-myc, c-myb, and c-fos--basal HIV-1 expression is regulated by transcription elongation.

Gene Expression Regulation, Viral↗
PubMed1992

Micro-invasive management of neonatal bilirubinemia.

The present study aims at analyzing the suitability of transcutaneous approach and filter paper technique using Minolta Jaundicemeter in the management of neonatal bilirubinemia. I compared serially measured values of Serum Bilirubin Index (SBI) by using filter paper technique and transcutaneous bilirubin index (TcBI) with serum bilirubin level determined by Diazo Method in 100 clinically jaundiced newborns and in 25 neonates at birth. The estimation of TcBI is simple, quick, reliable and non-traumatic to the newborn with no workload on the laboratory and technician. However, different nomograms are to be prepared for different laboratories, as also for the newborns with difference in skin pigmentation, gestational age and after phototherapy. SBI determined by filter paper technique eliminates these limitations. Moreover, the linear correlation was stronger between SBI and Diazo values (r = 0.9343, p < 0.001) in comparison to TcBI with Diazo values (r = 0.9090, p < 0.001). Further SBI readings almost correspond with actual serum bilirubin levels while corresponding TcBI values were much higher especially at higher diazo values. Thus TcBI can be used routinely for the surveillance of neonatal jaundice till it reaches a level corresponding to critical serum bilirubin level at which active management is required. At this point, serum bilirubin level may be confirmed by SBI.

Bilirubin↗
PubMed1992

Hereditary angioedema in a family.

Hereditary angioedema is an uncommon clinical condition. Life-long episodic brawny and non-itchy swelling of the extremities, face and trunk, with episodic abdominal pain and familial occurrence are the typical features. Oedema causing obstruction of airways may lead to suffocation and even death. The diagnosis can be confirmed by finding low levels of C1 esterase inhibitor, C4 and C2. Therapy with synthetic androgenic agents can ameliorate the condition to a large extent.

Adolescent↗
PubMed1992

Ultrasonic study of processed milk cream and vegetable oils.

Food systems are complex and inhomogeneous in nature. Ultrasonic propagation velocity in the food systems, in this case processed milk cream and vegetable oils, is studied. Ultrasonic properties of the food systems are similar to those of complex biological tissues. The presence of vegetable oil as an adulterant in the processed milk cream is detected with the help of a double-probe-through-transmission ultrasonic technique. The present study helps to maintain quality control of various food systems, particularly with regard to their adulteration, if any.

Animals↗
PubMed1992

Breeding habitats and their contribution to Anopheles stephensi in Panaji.

A one-year longitudinal study conducted in 9 categories of breeding habitats in Panaji, Goa, showed that 1.1% of the 67,360 breeding sites contained Anopheles stephensi immatures and the overall positivity varied from 0.4 to 3.5% with a peak in June. The habitat-wise proportion of An. stephensi was: wells, 0-1.3%; fountains, 1.4-11.4%; masonry tanks, 0.8-6.1%; overhead tanks, 0.1-4.0%; curing water in construction sites, 0.6-9.0%; groundwater tanks, 0-1.4%; tyres, 0-8.9%; barrels and tins, 0-5.4%; and intradomestic containers, 0-1.9%. An. stephensi was breeding along with An. subpictus, An. vagus, An. barbirostris, Culex quinquefasciatus, Cx. vishnui, Ae. aegypti, Ae. albopictus and Ae. vittatus.

Animals↗
PubMed1992

Experimental pathogenicity of Mollicutes of bovine udder origin in hamster tracheal ring organ culture.

Hamster tracheal-ring organ culture was employed to examine pathogenic effects of 8 isolates of Mollicutes of bovine udder origin. The tested Mollicutes could be categorized into two groups: (i) Mycoplasma F-38, M. mycoides var. capri, M. bovigenitalium mixed with M. bovirhinis, and M. bovigenitalium mixed with M. bovirhinis and Mycoplasma F-38 produced significant ciliostatic effect and infiltration of neutrophils and lymphocytes in lamina propria/subepithelium, hyperplasia and desquamation of epithelial lining cells and loss of cilia; and (ii) A. laidlawii, A. axanthum, an unidentified Acholeplasma and a mixed isolate of M. bovis, M. bovigenitalium, Mycoplasma F-38 and A. laidlawii showed insignificant ciliostatic effects and produced mild histopathological lesions. This correlates with the disease causing potentials of the strains.

Animals↗
PubMed1992

Cerebral glucose metabolic rates after 30 and 45 minute acquisitions: a comparative study.

This study was undertaken to determine if measurements of absolute regional cerebral metabolic rate for glucose (rCMRglc) and variance of rCMRglc are independent of time between 30 and 45 min following injection of the radiotracer. Sixteen subjects received two sets of 18FDG PET scans commencing 30 and 45 min following intravenous injection of 18FDG. No statistically significant differences were detected in either absolute rCMRglc or rCMRglc variance between the two sets of scans. These data demonstrate that for most FDG PET studies, scanning can commence 30 min after injection of the radiotracer without compromising the metabolic data.

Adult↗
PubMed1992

The effect of protease inhibitors, leupeptin and E64d, on differentiation of C2C12 myoblasts in tissue culture.

Intracellular calcium levels play an important role in myofibril disintegration and regeneration of muscle fibers. Earlier studies have shown that the calcium activated protease, calpain, is involved in the removal of Z-discs from myofibrils of striated muscle and the tripeptide-aldehyde, leupeptin, which is an inhibitor of calpain, inhibits this activity. In the present communication, we demonstrate that leupeptin and another calpain inhibitor, E64d, inhibit the fusion of mouse skeletal muscle C2C12 myoblasts to form multinucleated myotubes in tissue culture.

Animals↗
PubMed1992

Influence of selenium supplementation during chelation of lead in rats.

The influence of selenium supplementation during chelation therapy to reduce body burden and toxicity of lead was investigated in rats. Selenium had marginal effects on liver, kidney and blood lead decorporation by calcium disodium ethylenediamine tetra acetic acid (CaNa2EDTA) and activation of inhibited delta- aminolevulinic acid dehydratase (ALAD) activity by calcium trisodium diethylenetriamine penta acetic acid (CaNa3DTPA). Selenium supplementation however, had no influence on lead induced inhibition of renal and hepatic transaminases and alkaline phosphatase. The results suggest that selenium supplementation slightly augments lead mobilization by chelating drugs.

Administration, Oral↗
PubMed1992

Effect of unilateral ovariectomy and subsequent ovum implantation in mice.

Unilateral ovariectomy (ULO) was done on any stage of the cycle and the animals were mated within day 1 to day 21 to observe the acute and long term effect of ULO on ovum implantation. Implantation reduced in proportion to single ovary if the animals were mated within 24 hr of ULO. Increase in ovarian weight along with an increase in implantation number continued in mated mice and reached at peak on day 19-21 of ULO (sacrificed after 6 days i.e., 25-27 days of ULO). After ULO the remaining ovary compensated within day 5-6 of ULO even during pregnancy. Ovarian histology showed stimulation of small antral follicles in mice mated on day 3 of ULO (sacrificed after 6 days i.e., day 9 of ULO) along with a decrease of large antral follicles and pre-antral follicles. Preantral follicles were at peak on day 12-14. Large antral follicles attained a peak on day 4 which slowly decreased. The occurrence of implantation in such ULO conditions are discussed.

Animals↗
PubMed1992

Fine needle aspiration cytology, sonography and radionuclide scanning in solitary thyroid nodule.

One hundred and ninety three consecutive patients with solitary thyroid nodule (STN), with a mean age of 36.0 +/- 12.8 years and male to female ratio of 5.6:1, were studied. Ninety five percent of patients came from iodine deficient regions. Seventy two percent presented for local neck swelling, 12.4% for hyperthyroid state and in 7.7% STN was discovered incidentally. Scintigraphically, 77.7% of nodules were cold, 12.4% hot and 8.5% warm. Sonographic evaluation did not reveal any characteristic echotexture diagnostic of malignancy, but detected clinically nonpalpable accessory nodules in 20.6% of patients. Fine needle aspiration cytology was positive for malignancy in 6.2% of patients. Features of follicular and Hurthle cell neoplasm were seen in 12.9% of aspirates. Eighty eight (45.6%) STN were resected surgically. Histologically, there was one false positive and one false negative aspirate and a case of parathyroid adenoma on aspiration proved to be parathyroid carcinoma on histology.

Adult↗
PubMed1992

Stereochemical aspects of interaction of DNA binding domain of human progesterone receptor with d(AGGTCATGCT)2.

Structures of (i) 66 amino-acid fragment (residues 567-633) from DNA binding domain of human progesterone receptor (hPR), (ii) a ten base pair DNA sequence d(AGGTCATGCT)2 from hormone responsive element (HRE) and (iii) a complex of these two are optimised by computer modelling and molecular mechanics technique using extensive steric constraints from secondary structure predictions, comparison with the structures of known metalloproteins, geometric constraints imposed by tetrahedral coordination with the zinc ion and comparison with structures of DNA binding domains of human glucocorticoid and estrogen receptors (hGR and hER). Structure of the complex was obtained using genetic modification data on steroid receptors and general consensus about protein-DNA interaction. DNA is in distorted B conformation. Sequence dependent as well as protein-induced conformation changes are noticed. There is change in propeller twist, buckle and angle between glycosyl bonds. However, H-bonding network is preserved. The complex is stabilized with eighteen hydrogen-bonds, mainly between peptide side-chains and backbone phosphate. There are five specific H-bonds between basic amino acid side chains, Lys 22, Lys 26 and Arg 27, and DNA bases, A1, G3, G16 and A17. Gly 19, Ser 20 and Val 23 are in close proximity of DNA.

Amino Acid Sequence↗
PubMed1992

First practical colorimetric assay of lithium in serum.

We report a colorimetric method for determining lithium in blood serum without sample pretreatment or solvent-extraction steps. The method is based on a novel chromogenic ionophore that exhibits exceptionally high selectivity (much greater than 4000:1) for lithium over sodium. The standard curve for the method is linear up to 3.5 mmol/L and exceeds the therapeutic range for lithium. The results for 57 patients' samples correlated well with results obtained with an Instrumentation Laboratory flame photometer (r = 0.97).

Colorimetry↗
PubMed1992

Prevalence of delta virus infection in high risk population and hepatitis B virus related liver diseases.

Two hundred and fifty four high risk persons or patients with hepatitis B virus related liver disease (209 men, 45 women; age range 1-78 years) were tested for anti-delta antibody and IgM anti-HBc to determine the prevalence of delta agent coinfection and superinfection. The prevalence of delta infection was as follows: acute viral hepatitis 23/148 (16%) and chronic liver disease 17/92 (19%), and asymptomatic HBsAg carriers 1/6 (17%). In the high risk population, the delta antibody prevalence was as follows: multiple transfusion recipients 3/8 (38%), patients with chronic renal failure 1/5 (20%) and medical professionals 2/7 (29%). Of 44 patients (34 men, 10 women; age 3-63 years) with delta infection, 26 (59%) had coinfection and 18 (41%) had superinfection. Six patients with anti-delta antibody had received blood transfusion(s) and six others gave history of parenteral exposure.

Adolescent↗
PubMed1992

Identification of cis-acting DNA elements involved in the regulation of angiotensinogen gene expression.

Angiotensinogen is the precursor molecule of one of the most potent vasoactive substances, angiotensin-II. Angiotensinogen is normally synthesized in the liver and secreted into the plasma where it is converted into angiotensin-II by the combined proteolytic action of renin and angiotensin converting enzyme. Angiotensinogen levels in the plasma are modulated by a number of pathological and physiological factors. In order to understand the regulation of angiotensinogen gene expression, we have constructed an expression vector in which 688 bp of the 5'-flanking region of the rat angiotensinogen gene were attached to the chloramphenicol acetyl transferase (CAT) coding sequence. We have also obtained 5'-sequential deletion mutants from the rat angiotensinogen promoter attached to the CAT gene, and have identified multiple cis-acting DNA sequences involved in the regulation of angiotensinogen gene expression by transient transfection of these recombinant DNA molecules in human hepatoma cell lines, Hep3B, and HepG2.

Angiotensinogen↗