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Biomedical subjects

A K Reddy

Publications and source records attributed to A K Reddy.

At least 19 recordsLinked to original sources

Energy for the new millennium.

The evolution of thinking about energy is discussed. When the authors began collaborating 20 years ago, energy was typically considered from a growth-oriented, supply-side perspective, with a focus on consumption trends and how to expand supplies to meet rising demand. They were deeply troubled by the environmental, security and equity implications of that approach. For instance, about two billion people lack access to affordable modern energy, seriously limiting their opportunities for a better life. And energy is a significant contributor to environmental problems, including indoor air pollution, urban air pollution, acidification, and global warming. The authors saw the need to evolve a different perspective in which energy is provided in ways that help solve such serious problems. They argued that energy must become an instrument for advancing sustainable development--economically viable, need-oriented, self-reliant and environmentally sound development--and that the focus should be on the end uses of energy and the services that energy provides. Energy technological options that can help meet sustainable development goals are discussed. The necessity of developing and employing innovative technological solutions is stressed. The possibilities of technological leap-frogging that could enable developing countries to avoid repeating the mistakes of the industrialized countries is illustrated with a discussion of ethanol in Brazil. The role foreign direct investment might play in bringing advanced technologies to developing countries is highlighted. Near- and long-term strategies for rural energy are discussed. Finally, policy issues are considered for evolving the energy system so that it will be consistent with and supportive of sustainable development.

Brazil↗

Hemodynamic changes in apolipoprotein E-knockout mice.

Apolipoprotein E-knockout (ApoE-KO) mice develop advanced atherosclerotic lesions by 1 yr of age and have been well characterized pathologically and morphologically, but little is known regarding their cardiovascular physiology and hemodynamics. We used noninvasive Doppler ultrasound to measure aortic and mitral blood velocity and aortic pulse-wave velocity in 13-mo-old ApoE-KO and wild-type (WT) mice anesthetized with isoflurane. In other mice from the same colony, we measured systolic blood pressure, body weight, heart weight, cholesterol, and hematocrit. Heart rate and blood pressure were comparable (P = not significant) between ApoE-KO and WT mice, but significant decreases (P < 0.001) were found in body weight (-22%) and hematocrit (-11%), and significant increases were found in heart weight (+23%), aortic velocity (+60%), mitral velocity (+81%) (all P < 0.001), and pulse-wave velocity (+13%, P < 0.05). We also found inflections in the aortic arch velocity signal consistent with enhanced peripheral wave reflection. Thus ApoE-KO mice have phenotypic alterations in indexes of peripheral vascular resistance and compliance and significantly elevated cardiac outflow velocities and heart weight-to-body weight ratios.

Animals↗

Using ferritin levels to determine iron-deficiency anemia in pregnancy.

BACKGROUND: Standard obstetrical practice has included iron therapy for patients with anemia without requiring the determination of iron deficiency. However, the proportion of pregnant women with anemia who have such a deficiency may be relatively modest. We instituted a practice protocol using serum ferritin levels to determine the proportion of women undergoing prenatal care who had both anemia and iron deficiency. METHODS: We evaluated consecutive women entering prenatal care. Those with anemia (hemoglobin level <11 mg/dL) underwent testing for serum ferritin level and other hematologic variables. RESULTS: A total of 182 patients entered prenatal care. Hemoglobin data were available for 173 (95%). Thirty-eight (22%) had anemia (hemoglobin level <11 mg/dL); 1 of those women was excluded from the study. Using a ferritin level of 12 mg per dL as the cutoff for iron deficiency, 54% (20) of the 37 remaining patients with anemia had an iron deficiency, and 46% (17) had anemia not related to such a deficiency. Use of hematologic indices provided on complete blood count were not useful in predicting iron deficiency based on serum ferritin levels. CONCLUSIONS: In our population of prenatal patients with anemia, only approximately half had an iron deficiency. Diagnostic and therapeutic approaches to screening for anemia in pregnancy should be reconsidered and further evaluated.

Adolescent↗

Novel euglycemic and hypolipidemic agents. 1.

A series of [[(heterocyclyl)ethoxy]benzyl]-2,4-thiazolidinediones have been synthesized by the condensation of corresponding aldehyde 1 and 2,4-thiazolidinedione followed by hydrogenation. Both unsaturated thiazolidinedione 2 and its saturated counterpart 3 have shown antihyperglycemic activity. Many of these compounds have shown superior euglycemic and hypolipidemic activity compared to troglitazone (CS 045). The indole analogue DRF-2189 (3g) was found to be a very potent insulin sensitizer, comparable to BRL-49653 in genetically obese C57BL/6J-ob/ob and 57BL/KsJ-db/db mice. Pharmacokinetic and tissue distribution studies conducted on BRL-49653 and DRF-2189 (3g) indicate that these drugs are well-distributed in target tissues. On the basis of euglycemic activity as well as enhanced selectivity against reduction of triglycerides in plasma, DRF-2189 (3g) has been selected for further evaluation.

Animals↗

The Yelandur study: a community-based approach to epilepsy in rural South India--epidemiological aspects.

Data on the epidemiology of epilepsy in a rural community in a developing country would be of value in planning a decentralized management of this malady in its early stages commensurate with available local resources. A detailed screening instrument covering various seizure types was used by trained paramedical workers in a door-to-door survey of a population of 64,963 in rural South India. The prevalence period was from 1 April 1990 to 31 March 1991. The crude prevalence rate per 1000 for active epilepsy was 4.38 for males, 3.40 for females and 3.91 for both. The minimum and maximum prevalence rates, the latter computed from a validation sample, were 3.91 and 4.63 for active epilepsy; 0.28 and 0.77 for inactive epilepsy and 4.19 and 5.41 for life-time prevalence. In addition, corresponding figures for hot-water epilepsy, a type of reflex epilepsy peculiar to this area, were 2.49 and 2.99 for active phase; 0.35 and 0.85 for inactive phase and 2.85 and 3.83 for life-time prevalence. The incidence rate for epilepsy was 49.3 per 100,000, the same as in developed countries. These data do not support the concept that the prevalence of epilepsy in developing countries is twice that in the developed world. However, the role of local/regional variations should be borne in mind before extrapolating the figures to an entire country.

Adolescent↗

Fenestration gingival defect in erupting permanent mandibular incisors: a case report.

Bilateral fenestration of the labial gingival tissue of the permanent mandibular central incisors is described. The situation was followed over a 2-year period with no treatment other than prophylaxis and oral hygiene instruction. The final outcome was an apical positioning of the gingival margin, which was lower than that of the adjacent uninvolved teeth.

Child↗

Colloid cyst xanthogranuloma of the third ventricle--a case report.

A colloid xanthogranuloma of the third ventricle is described. Presenting features were symptoms of raised intracranial tensions and two episodes of seizures. The pathogenesis, clinical and radiological features, differential diagnosis and treatment of this rare benign lesion are briefly discussed.

Adolescent↗

Twice versus thrice weekly ECT in melancholia: a double-blind prospective comparison.

Thirty patients with major depressive disorder of melancholic subtype were randomly allocated to receive ECT either twice or thrice a week. Double-blind ratings on the Hamilton Scale for Depression and Clinical Global impression showed no differences in the outcome through 4 weeks of trial as well as at 6-month follow-up. Cumulative seizure duration was higher in the thrice weekly group but not significantly so in spite of having received a significantly greater number of ECTs. The results indicate that ECT given thrice a week conferred no advantage over ECT given twice a week.

Adult↗

The effects of zwitterionic surfactants on skin barrier function.

The action of five zwitterionic surfactants on the barrier function of hairless mouse skin has been studied in vitro. The surfactants considered were dodecylbetaine and hexadecylbetaine (C12BET and C16BET, respectively), hexadecylsulfobetaine (C16SUB), N,N-dimethyl-N-dodecylamine oxide (C12AO), and dodecyltrimethylammonium bromide (C12TAB). Excised skin was pretreated with each surfactant, at various concentrations, for 16 hr, following which the permeation of a model compound, nicotinamide, was measured. The action of the surfactants was assessed by comparing nicotinamide flux through surfactant-pretreated skin with that across control membranes which were exposed to buffer alone for 16 hr. All surfactants decreased skin barrier function to some extent. The degree of nicotinamide penetration enhancement induced was correlated with the ratio of the surfactant pretreatment concentration to the surfactant critical micelle concentration, suggesting that solubilization of stratum corneum lipids may be an important mechanism in explaining the effects observed. More detailed studies with 14C-radiolabeled C12BET and C16BET showed that the dodecyl analog was itself well absorbed, whereas the C16 compound partitioned into the skin favorably but then transferred only very slowly into the receptor phase. These observations were consistent with toxicity studies (albeit at much higher concentrations in a different animal model, the rat) which indicated that the dermal LD50 of C12BET was significantly less than that of C16BET (the value for which was so large that it could not be reliably determined). Overall, this study provides, we believe, useful information pertinent to the potential dermal toxicity of the surfactants considered following occupational or environmental exposure.

Administration, Oral↗

Antiproliferative effects of amphiphilic molecules.

Previous investigations indicated that certain long chain amphiphiles possess immunosuppressive activity. Here we tested this concept by studying the ability of a series of nitrogen-containing amphiphiles of varying hydrocarbon chain lengths to inhibit the human mixed lymphocyte reaction (MLR). Seventeen of 29 compounds were classified as inhibitory in the MLR but not toxic to the cells, six were both inhibitory and toxic to the cells, and six were inactive at the concentrations tested. In contrast, cyclosporin A inhibited the MLR and was not toxic. With the hypothesis that the amphiphiles might act to inhibit cell proliferation in a nonspecific manner, they were tested on a battery of tumor cell lines at concentrations that did not show toxicity in the MLR. Whereas cyclosporin A did not inhibit the proliferation of tumor cells, most of the active amphiphiles did inhibit tumor cell proliferation and, in addition, killed the tumor cells. These results suggest that the amphiphiles are antiproliferative and do not show specificity of action on cells of the immune system. Finally, based on available data that showed poor skin penetration, no significant human health risk seems likely from skin contact with these chemicals, as they are currently used in household products or rinse-off personal care products.

Adult↗

Mesencephalic haematoma, successful surgical evacuation. Case report.

A case of mesencephalic haematoma is reported. Emergency surgical evacuation of haematoma was done. The patient improved and has done well for five years. Subtemporal and infratentorial supracerebellar approaches have been used earlier to remove mesencephalic haematoma. It is possible to remove caudal midbrain haematoma via a IVth ventricular approach causing minimal damage.

Brain Neoplasms↗

Percutaneous absorption, metabolism, and hemolytic activity of n-butoxyethanol.

A series of studies was conducted to examine the percutaneous absorption, distribution, excretion, and hemolytic activity of n-butoxyethanol (BE). Rats receiving a subcutaneous dose of 14C-labeled BE excreted the radioactivity in the urine (79%), expired air (10%), and feces (0.5%) within 72 hr. Of the organs analyzed, thymus and spleen showed elevated specific radioactivities as compared with blood. A percutaneous application of BE on rats, under nonocclusive conditions, showed 25-29% absorption within 48 hr. Peak blood levels of BE occurred at 2 hr after application; butoxyacetic acid (BAA) was found to be the major metabolite. Comparison of in vitro skin penetration data showed the following absorption pattern of BE: hairless rat much greater than pig greater than human skin. Hemolysis and associated hematological changes were noted in the rats which received single dermal applications of 260-500 mg/kg of BE. In vitro, BAA showed markedly greater hemolytic ability on rat erythrocytes than did BE. Human erythrocytes showed no hemolysis when incubated with BE or BAA at concentrations that are hemolytic to rat erythrocytes. An intravenous dose of 62.5 mg/kg of BE does not result in hemolysis or hemoglobinuria in the rat. The rat may be an animal model with increased susceptibility to the effects of BE compared with humans because of its rapid percutaneous absorptive ability and its greater hemolytic sensitivity.

Administration, Topical↗

Selected pulmonary biochemical and hematological changes produced by prolonged hypoxia in the rat.

Rats were exposed to 12% O2 (1 atm) for 48 hr, then 10% O2 for the duration of the exposures. Significant elevations in enzymes of the glutathione peroxidase system were found in the lungs of rats killed 3.5, 7.5, and 12.5 days of exposure compared to air-breathing controls. Superoxide dismutase was also elevated after hypoxia but nonsignificantly. Animals killed 12.5 days after exposures exhibited 75% (P less than 0.05) more thiobarbituric acid reactive products in their lungs compared to controls. These results along with significant increases of lung lipid peroxidation and in an augmentation of protective antiperoxidative lung defense capabilities. Hypoxia also resulted in enzyme elevations of lung phosphofructokinase and pyruvate kinase, which may indicate an adaptive increase in lung glycolytic capabilities which would be helpful in maintaining lung tissue energy requirements during hypoxia. In addition, it was confirmed that red blood cell count, hemoglobin and hematocrit values increased after prolonged hypoxia. The results of this study might also reflect enzyme elevation/induction due to cellular reparative-proliferative processes following hypoxia.

Animals↗

Malignant fibrous histiocytoma arising from the meninges of the posterior fossa.

A case of malignant fibrous histiocytoma presenting as a cerebellar mass in a young man is described. The tumor was found to be arising from the dura mater and infiltrating the cerebellum. The ultrastructural and immunocytochemical studies confirmed the mesenchymal origin of the neoplasm. Focal reactive astrocytomalike areas were observed in the midst of this tumor.

Adult↗

Intraspinal arachnoid cysts.

Arachnoid cysts are rare lesions responsible for spinal cord compression. Five cases of congenital intraspinal arachnoid cysts are reported. Three cases of thoracic and two cases of thoracolumbar region were encountered. The clinical presentation was one of progressive spastic paraparesis. The characteristic radiological features are described. Surgery was successful in all cases.

Adolescent↗