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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 1,441 records · Page 80Linked to original sources
PubMed1991

An investigation of environmental impact on health of workers at retail petrol pumps.

Ninety-four male pump workers, employed in 41 petrol filling stations in Kanpur (formerly Cawnpore) and Lucknow--both in the Ganges plain of north India--were clinically examined. Headache, redness in eyes, lacrimation and signs like coated and/or furred tongue, throat and/or conjunctival congestion and carious teeth were significantly higher (P less than 0.05) in workers exposed to petrol fumes than in controls, as also was the level of phenol in urine (P less than 0.01). Environmental measurements revealed higher concentrations of benzene, sulphur dioxide and photoionizable dust in the air at petrol stations, and most of the symptoms and signs could be attributed to petrol fumes and other environmental pollution.

Adolescent↗
PubMed1991

Effect of Light Quality on Phycobilisome Components of the Cyanobacterium Spirulina platensis.

Phycobilisomes from the nonchromatic adapting cyanobacterium Spirulina platensis are composed of a central core containing allophycocyanin and rods with phycocyanin and linker polypeptides in a regular array. Room temperature absorption spectra of phycobilisomes from this organism indicated the presence of phycocyanin and allophycocyanin. However, low temperature absorption spectra showed the association of a phycobiliviolin type of chromophore within phycobilisomes. This chromophore had an absorption maximum at 590 nanometers when phycobilisomes were suspended in 0.75 molar K-phosphate buffer (pH 7.0). Purified phycocyanin from this cyanobacterium was found to consist of three subparticles and the phycobiliviolin type of chromophore was associated with the lowest density subparticle. Circular dichroism spectra of phycocyanin subparticles also indicated the association of this chromophore with the lowest density subparticle. Absorption spectral analysis of alpha and beta subunits of phycocyanin showed that phycobiliviolin type of chromophore was attached to the alpha subunit, but not the beta subunit. Effect of light quality showed that green light enhanced the synthesis of this chromophore as analyzed from the room temperature absorption spectra of phycocyanin subparticles and subunits, while red or white light did not have any effect. Low temperature absorption spectra of phycobilisomes isolated from green, red, and white light conditions also indicated the enhancement of phycobiliviolin type of chromophore under green light.

Journal Article↗
PubMed1991

The role of a critical care unit in an epidemic.

The role of a critical care unit in life-threatening situations is well established. The management of 52 children with acute gastroenteritis and 22 children with acute paralytic poliomyelitis as part of recent epidemics is described. The solutions to the problems in the critical care management of these 74 victims (out of a total of 6197 patients admitted during the epidemics) are discussed.

Acute Disease↗
PubMed1991

Penile strangulation.

Penile strangulation is a rare injury that requires urgent management. Non-metallic, thin objects are easy to remove but can cause severe injury. Metallic objects are difficult to remove but the injuries are usually less severe. Penile ulceration and oedema in children may well indicate the presence of a strangulation object. We describe a new hammer and chisel method for removing such objects.

Adolescent↗
PubMed1991

Ultrasonography in optic nerve head avulsion.

The diagnosis of post traumatic optic nerve avulsion is often obscured by the presence of concomitant vitreous haemorrhage. Electrodiagnostic tests, CT scan and fluorescein angiography have not proved helpful in substantiating the diagnosis of this entity in the early stages. We herein present the echographic features in a case of post traumatic optic nerve avulsion that, to the best of our knowledge, have not been previously described. The role of ultrasonography in the diagnosis of suspected optic nerve head avulsion has been high-lighted.

Adolescent↗
PubMed1991

Immunodiagnosis of aspergillosis.

Aspergillus species are ubiquitous fungi and have been implicated as the causative agents of a variety of lung disorders in humans. These disorders include allergic, saprophytic, and systemic manifestations. The allergic disorders mainly affect atopic persons, and invasive or systemic diseases affect immunosuppressed individuals. Immunodiagnosis can help the practitioner diagnose these diseases. Demonstration of circulating antibodies is a useful criterion, but the lack of dependable and standardized antigens is a limiting factor in the diagnosis of most Aspergillus-induced diseases. Despite this limitation, however, immunodiffusion and enzyme-linked immunosorbent assays have been widely used for the detection of antibodies in the sera of patients with aspergillosis. Similarly, crude and semipurified antigens are being used to demonstrate skin hypersensitivity in patients, and several methods have been useful in the detection of antigenemia in patients with invasive aspergillosis. With a growing number of reports on the incidence of aspergillosis and an increase in the number of immunosuppressed individuals in the population, more rapid methods and more reliable reagents for immunodiagnosis are needed. With recent attempts at obtaining reliable reagents for through hybridoma technology and molecular biological techniques, substantial progress toward efficient immunodiagnosis may be achieved.

Animals↗
PubMed1991

Antibody recognition and isoelectrofocusing of antigens of the malaria parasite Plasmodium yoelii.

Inbred BALB/c mice were either immunized with Triton X-100-extracted antigens of blood-stage Plasmodium yoelii or infected with P. yoelii and cured in three successive schedules. Whereas the immunized BALB/c became only partially protected from subsequent challenge infection with blood-stage P. yoelii, the convalescent mice acquired total immunity. When total P. yoelii antigen extract was resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and immunoblotted with anti-P. yoelii serum, five major protein bands of 150, 84, 40, 19, and 16 kDa were recognized by the sera of fully protected convalescent mice but not by the sera of partially protected mice. The utility of comparing reactivities of sera from fully protected and partially protected malaria hosts and the possibility that antigens uniquely recognized by the convalescent mouse sera may contribute to immunity against P. yoelii infection are discussed. Although previously reported to be an effective adjuvant for immunization against P. yoelii infection in (BALB/c x C57BL)F1 hybrid mice, saponin did not promote protection any better than did Freund adjuvant in BALB/c mice immunized with detergent-extracted P. yoelii antigen. Most of the P. yoelii proteins (14 to 250 kDa) found in Triton X-100 extracts of P. yoelii-parasitized erythrocytes isoelectrofocused as a single peak in the pH region 4.4 to 4.6, suggesting a rationale for previous findings that the most anti-P. yoelii protective and T-helper activities are induced by antigens isoelectrically focused in a fraction of similar pH.

Animals↗
PubMed1991

Tissue-specific transcription of the cardiac myosin light-chain 2 gene is regulated by an upstream repressor element.

Physiological expression of the cardiac muscle myosin light-chain 2 (MLC-2) gene in chickens is restricted to cardiac muscle tissue only, at least during the late embryonic to adult stages of development. The mechanism by which cardiac MLC-2 gene expression is repressed in differentiated noncardiac muscle tissues is unknown. Using sequential 5'-deletion mutants of the cardiac MLC-2 promoter introduced into primary skeletal muscle cells in culture, we have demonstrated that a 89-bp region, designated the cardiac-specific sequence (CSS), is essential for repression of cardiac MLC-2 expression in skeletal muscle. Removal of the CSS sequence alone allows transcription in skeletal muscle cells without affecting the transcriptional activity of the promoter in cardiac muscle cells. DNase I footprinting and gel shift assays indicate that protein binding to sequences in the CSS domain occurs readily in nuclear extracts obtained from skeletal muscle but not in extracts isolated under identical conditions from cardiac muscle. Thus, it appears that a negative regulatory mechanism accounts for the lack of expression of the cardiac MLC-2 gene in skeletal muscle and that the CSS element and its binding proteins are important functional components of the regulatory apparatus which ensures the developmental program for cardiac tissue-specific gene expression.

Animals↗
PubMed1991

Organization of a cloned repetitive DNA fragment in mosquito genomes (Diptera: Culicidae).

The structure and genomic organization of a cloned 5.2-kb repetitive DNA fragment, H-85, isolated from the Aedes albopictus genome have been examined. In situ hybridization of the 3H-labeled H-85 DNA to the meiotic and mitotic chromosome preparations of Ae. albopictus shows that the sequences homologous to H-85 DNA are dispersed throughout the length of all three pairs of chromosomes. A similar pattern of in situ hybridization appears in Aedes seatoi, Aedes flavopictus, and Aedes aegypti. The study shows that the arrangement of sequences in the cloned 5.2-kb fragment is rare in the Ae. albopictus genome. Dot-blot hybridization reveals that the sequences homologous to H-85 DNA are present in 12 species of mosquitoes examined, belonging to six genera in subfamilies Culicinae ad Anophelinae. The H-85 sequences are also present in the genome of Mochlonyx velutinus of the nematocerous family Chaoboridae, earlier proposed as the ancestor of the mosquito family Culicidae. Although the sequences homologous to H-85 DNA are present in different species of mosquitoes, they have diverged in their structure and organization. The cloned 5.2-kb fragment is composed of elements of different and independently evolving repetitive DNA families.

Aedes↗
PubMed1991

Hepatotoxicity of rifampin and isoniazid. Is it all drug-induced hepatitis?

Serologic markers for hepatitis viruses were studied in 40 children who developed acute hepatitis during antituberculosis therapy with rifampin and isoniazid, with the aim of assessing the contributory role of these viruses toward producing hepatic injury. Hepatitis A and B were confirmed in 7.5 and 35% patients, respectively, by IgM antibodies. Epidemiologic evidence suggested the possibility of non-A, non-B hepatitis in at least a few of the remaining 23 children. Hepatitis B was seen more often in children with severe tubercular disease (72%) and was largely (92.8%) parenterally transmitted. The study highlights that the endemicity of viral hepatitis in developing countries, among other factors, could also be responsible for the reported higher incidence of hepatotoxicity from developing countries and also for the increased risk of hepatotoxicity seen in severe tubercular disease.

Chemical and Drug Induced Liver Injury↗
PubMed1991

Quantitative magnetic resonance imaging in Rett syndrome.

Rett syndrome (RS) is a progressive neurological disorder of females, characterized by the early onset of autistic behavior, ataxia, and "handwringing" movements. The present magnetic resonance imaging study was undertaken with the purpose of investigating whether structural brain abnormalities of RS patients are similar to those recently reported in autism. The subject population consisted of eight patients and an equal number of age- and sex-matched controls. Area and shape measurements were taken at selected anatomical levels for the following structures: brain hemisphere, corpus callosum, midbrain, pons, lobules I-V and VI-VII of the cerebellum, and head of the caudate. Results revealed significant differences in area for the whole brain hemisphere (p < 0.05) and in both right and left caudate (p < 0.04). These morphological findings are different from those recently reported in autism and emphasize the involvement of the striatal system in RS.

Child↗
PubMed1991

Haemodynamic effects of ketanserin following coronary artery bypass grafting.

The haemodynamic effects of ketanserin were studied consecutively in seventeen patients in the intensive care unit following coronary artery bypass grafting. Hypertensive patients (Group 1, systolic blood pressure (SBP) greater than or equal to 150 mmHg following discontinuation of nitroprusside, n = 10) received intravenous ketanserin 10 mg and infusion of 0.1 mg.kg-1.hr-1 with additional boluses as required to maintain SBP less than or equal to 130 mmHg for one hour. Non-hypertensive patients (Group 2, SBP less than 150 mmHg, n = 7) received a 5 mg bolus and the same infusion. Ketanserin significantly decreased arterial blood pressure (P less than 0.001) in all patients in Group 1. Heart rate was decreased but not significantly. Cardiac index, systemic and pulmonary vascular resistance and pulmonary shunt fraction were not significantly altered from pre-ketanserin values when blood pressure was controlled with nitroprusside. Normotensive patients in Group 2 did not show any undesirable hypotension or significant haemodynamic changes. Mean nitroprusside dose requirements following ketanserin therapy were significantly reduced by 91.6% in Group 1 and 78.4% in Group 2 (P less than 0.05). Ketanserin is effective in treating hypertension following coronary artery bypass grafting with an advantage of lack of reflex tachycardia.

Adult↗