Central component of the cario-accelerator action of angiotensin II in dogs.

Injection of angiotensin II into a lateral cerebral ventricle (I.C.V.) or into a peripheral vein of anaesthetized dog elicited a rise in blood pressure and transient bradycardia followed by sustained tachycardia. Spinal transection at C2 and bilateral vagotomy abolished the central cardiovascular effect of I.C.V. angiotensin. However, in spinal transected dogs the usual pressor response to intravenous angiotensin was observed. Since the transient bradycardia was absent in bilaterally vagotomized dogs or in dogs with their blood pressure stabilized by means of a mechanical buffer devise it must be reflex in origin. The tachycardia was more marked in vagotomized dogs. Prior administration of a beta adrenergic receptor blocking agent propranolol, blocked the tachycardia, but the pressor response was unaffected. The cardiovascular responses to centrally administered angiotensin were practically abolished by prior treatment of dogs with reserpine or by extirpation of both adrenal glands. Thus it may be concluded that ICV angiotensin induces a centrogenic release of catecholamines from the adrenal medulla which is responsible for the cardiovascular responses.     

Altered gene expression in human hepatoma HepG2 cells exposed to low-level 2,4-dichlorophenoxyacetic acid and potassium nitrate.

2,4-dichlorophenoxyacetic acid (2,4-D) and nitrate are agricultural contaminants found in rural ground water. It is not known whether levels found in groundwater pose a human or environmental health risk, nor is the mechanism of toxicity at the molecular/cellular level understood. This study focused on determining whether 2,4-D or nitrate at environmentally realistic levels elicit gene expression changes in exposed cells. cDNA microarray technology was used to determine the impact of 2,4-D and nitrate in an in vitro model of exposure. Human hepatoma HepG2 cells were incubated with 2,4-D or nitrate alone for 24 h. Cell viability (neutral red assay) and proliferation (BrdU incorporation) were assessed following exposure. Total RNA from treated and control cells were isolated, reverse transcribed and reciprocal labelled with Cy3 or Cy5 dyes, and hybridized to a human cDNA microarray. The hybridized microarray chips were scanned, quantified and analyzed to identify genes affected by 2,4-D or nitrate exposure based on a two-fold increase or decrease in gene expression and reproducibility (affected in three or more treatments). Following filtering, normalization and hierarchical clustering initial data indicate that numerous genes were found to be commonly expressed in at least three or more treatments of 2,4-D or nitrate tested. The affected genes indicate that HepG2 cells respond to environmental, low-level exposure and produce a cellular response that is associated with alterations in the expression of many genes. The affected genes were characterized as stress response, cell cycle control, immunological and DNA repair genes. These findings serve to highlight new pathway(s) in which to further probe the effects of environmental levels of 2,4-D and nitrate.     

Adenosine deaminase activity in leprosy

Adenosine deaminase (ADA) activity was studied in serum and peripheral blood lymphocytes of leprosy patients and healthy controls. Serum ADA levels were found to be elevated in tuberculoid as well as lepromatous cases compared to control subjects. Serum ADA activity was significantly higher in tuberculoid cases than in the lepromatous group. Lymphocyte adenosine deaminase activity showed a similar trend. These results suggest that, since the overall activity of the enzyme is not deficient in leprosy, the cellular immune abberation seen in the different types of leprosy may be due to abnormal proliferation of different subsets of lymphocytes in response to M. leprae.     

Prognostic significance of serum iron levels in cases of Japanese encephalitis.

Forty-one children with acute laboratory confirmed Japanese encephalitis were studied. Serum iron concentrations were consistently low following Japanese encephalitis virus infection, with the levels being of prognostic significance.     

Lingual tuberculosis

Human infection with the Mycobacterium Tuberculosis is common but an ulcerative granulomatous lesion of the tongue as the presenting feature of pulmonary tuberculosis is very unusual. Only a few cases having been reported in the literature (Weaver, 1976). This Daner presents a rare case of lingual tuberculosis.     

Revisiting the impact of phenylephrine hydrochloride on static and dynamic accommodation

Purpose:

Phenylephrine hydrochloride (PHCl), a commonly used mydriatic agent, causes a small but significant deterioration of accommodation. The relative roles of pharmacology and optics in this deterioration, however, remain unascertained. The study determined the combined impact of PHCl concentration (pharmacology) and pupil size (optics) on the static and dynamic characteristics of accommodation.

Materials and Methods:

A total of 16 emmetropic Indian adults viewed a high-contrast visual target that switched between 67 and 33 cm viewing distance (1.5D stimulus) with their right eye (left eye occluded using infrared transmitting filter) through natural pupils and through 8, 6, 4, and 1 mm diameter artificial pupils. This protocol was repeated once without PHCl and once each with 2.5%, 5%, and 10% PHCl. Consensual accommodation of the left eye was recorded using infrared photorefraction (60 Hz).

Results:

Relative to no PHCl, the horizontal pupil diameter of left eye was significantly larger (P < 0.001) and the response magnitude and peak velocity of accommodation and disaccommodation were modestly but significantly smaller (P < 0.02 for all) for all concentrations of PHCl tested. There was no significant difference in these parameters across the three drug concentrations (P > 0.4 for all). The response magnitude and peak velocity also decreased significantly with pupil diameter, at similar rates for the no PHCl and the three PHCl conditions (P < 0.001 for all).

Conclusion:

The reduction in accommodative performance with all drug concentrations and with pupil diameter suggests independent roles of pharmacology and optics in determining accommodative performance with PHCl. The reduction in accommodative performance is, however, modest and may be clinically irrelevant in Indian eyes.