High Blood Pressure Induced by Audiovisual Stimulation in Young Rats: Effect of Antihypertensive Agents

ABSTRACT

High systolic blood pressure (BP) was induced in young Wistar rats by daily exposure for 30 mins to environmental stimuli consisting of intense (100 dB) sound of 7500 cps and flashing light (0.3 cps). Maximal BP enhancement was obtained after the application of both these stimuli for 3 consecutive days. Such a hypertensive response was detected 24 hrs, but not 1 hr after the trial. High BP backed to normal 72 hrs after discontinuation of the audiovisual stimulation trials. Clinically effective antihypertensive agents (clonidine, prazosin, propranolol, practolol and metoprolol) as well as a new compound under investigation (cicletanine) were proved active in this model. Normotensive nonstressed rats run in parallel did not show any variation in their BP after administration of the same dose of the drugs assayed. This experimental model of hypertension may be a useful tool not only to test new antihypertensive agents but also to study the intriguing question of the role of stress in the development and maintenance of essential hypertension.     

The disproportionate burden of HIV and STIs among male sex workers in Mexico City and the rationale for economic incentives to reduce risks

Introduction

The objective of this article is to present the rationale and baseline results for a randomized controlled pilot trial using economic incentives to reduce HIV and sexually transmitted infection (STI) risk among male sex workers (MSWs) in Mexico City.

Methods

Participants (n=267) were tested and treated for STIs (chlamydia, gonorrhoea, syphilis and HIV) and viral hepatitis (hepatitis B and C), received HIV and STI prevention education and were randomized into four groups: (1) control, (2) medium conditional incentive ($50/six months), (3) high conditional incentive ($75/six months) and (4) unconditional incentive ($50/six months). In the conditional arms, incentives were contingent upon testing free of new curable STIs (chlamydia, gonorrhoea and syphilis) at follow-up assessments.

Results

Participants’ mean age was 25 years; 8% were homeless or lived in a shelter, 16% were unemployed and 21% lived in Mexico City less than 5 years. At baseline, 38% were living with HIV, and 32% tested positive for viral hepatitis or at least one STI (other than HIV). Participants had a mean of five male clients in the previous week; 18% reported condomless sex with their last client. For 37%, sex work was their main occupation and was conducted mainly on the streets (51%) or in bars/discotheques (24%) and hotels (24%). The average price for a sex transaction was $25 with a 35% higher payment for condomless sex.

Conclusions

The findings suggest that economic incentives are a relevant approach for HIV prevention among MSWs, given the market-based inducements for unprotected sex. This type of targeted intervention seems to be justified and should continue to be explored in the context of combination prevention efforts.     

Jatrophone Inhibits Platelet Rich Plasma Aggregation from Man,Rat and Guinea-pig Induced by Different Agents

The effect of jatrophone (2.5–100 μM ), a diterpene isolated from Jatropha elliptica , upon the aggregation (platelet rich plasma) induced by several agents in different animal species was examined. At the same range of inhibitory concentrations (24.0–43.0 μM ) previously shown to inhibit contractions triggered by different agents in isolated muscle preparations, jatrophone markedly inhibited platelet aggregation. This effect was dose-dependent and it was reversible for up to 30 min. It is concluded that this nonspecific effect could reflect an action of jatrophone either at an intracellular step in the signal transduction process, which is common to different agonists, or at the level of extracellular and/or intracellular Ca²⁺ mobilization.     

Indices of social risk among first attenders of an emergency mental health service in post-conflict East Timor: an exploratory investigation

OBJECTIVE: Little is known about the profile of patients treated in mental health services in low-income, post-conflict countries, especially in the post-emergency phase. We postulated that patients attending the first community mental health service in East Timor would be characterized not only by mental disturbance but by high levels of social vulnerability. METHOD: Drawing on existing methods and on consultations with East Timorese mental health staff, five social indicators were identified: dangerousness; inability to undertake life-sustaining self-care; bizarre behaviour; incapacitating distress; and social unmanageability. Adequate levels of interrater reliability (65-91%) were achieved in identifying these indicators from case notes. Forty-eight randomly selected case notes were analyzed to ascertain the prevalence of social risk factors as well as the referral source and broad diagnostic groupings. RESULTS: Major referral sources were the family, humanitarian agencies and the police. Twenty-nine percent met criteria for dangerousness; 42% for inability to undertake self-care; 58% for bizarre behaviour; 75% for distress; and 19% for unmanageability. Ninety-eight percent fulfilled at least one social indicator, with the modal score being 2. CONCLUSIONS: Although the approach to documentation and analysis was preliminary, the data suggest that a focus on social risk indicators may assist in determining those mentally disturbed persons in need of priority care in resource-poor post-conflict countries.