Nifs and Sufs in malaria.

This review assembles data from three bodies of literature (bacterial genetics, plastid biogenesis and parasitology) that seldom have much direct cross-talk. After overcoming terminological complications to sort out microbial nifS from sufS genes, we connect a bacterial operon, recently found to be involved in iron metabolism, the formation of [Fe-S] clusters and oxidative stress to a potentially important gene (sufB) carried on the degenerate plastid genome of malaria and related parasites.

Correlation of cyclic AMP accumulation and relaxant actions of salmeterol and salbutamol in bovine tracheal smooth muscle.

1. The ability of salmeterol to stimulate cyclic AMP accumulation and relaxation has been compared with that of salbutamol in bovine tracheal smooth muscle. In addition, the anti-spasmogenic effects of these agents and their abilities to modulate histamine-stimulated [3H]-inositol phosphate accumulation have also been investigated. 2. In tissue strips, a close temporal correlation was found to exist between salmeterol (0.1 microM)-induced relaxation of methacholine (500 nM)-induced tone and cyclic AMP accumulation, both maximal reversal of induced tone (26.2 +/- 6.0%) and maximal levels of cyclic AMP accumulation being achieved after 30-40 min. In contrast to salmeterol, salbutamol exerted greater and more rapid effects on both parameters. Maximal reversal of methacholine-induced tone (79.3 +/- 14.0%) and maximal levels of cyclic AMP accumulation were produced within 5 min. 3. Salmeterol-induced cyclic AMP accumulation (EC50 = 5.3 [1.8 - 15.2] nM) and inhibition of histamine (0.1 mM)-stimulated [3H]-inositol phosphate accumulation (IC50 = 1.4 [0.3-6.3] nM) were both more potent than those induced by salbutamol (EC50 = 169 [99 - 290] nM; IC50 = 13.8 [7.0 - 27.4] nM). However, maximal effects exerted by each of these agents were similar in magnitude. 4. Anti-spasmogenic effects were examined by beta-adrenoceptor agonist application to tissue strips prior to construction of spasmogen concentration-effect curves. Both salmeterol and salbutamol exerted more marked inhibition of the contractile response induced by histamine than that induced by methacholine, salmeterol being the more potent agent, while salbutamol produced a greater maximal inhibitory effect. 5. The results demonstrate that salmeterol is a more potent agent than salbutamol and have highlighted a close temporal correlation between promotion of cyclic AMP accumulation and tissue relaxation stimulated by each agent when both parameters are measured under identical conditions.

The optimal technique for obtaining a Papanicolaou smear with the Cervex-Brush.

BACKGROUND: The Cervex-Brush (Rovers, The Netherlands; Unimar, Wilton, Conn) is a cervical cytologic sampling device used to simultaneously collect endocervical and ectocervical cells. The optimal method for using this device to collect cervical epithelial cells for a Papanicolaou smear has not been described in the medical literature. METHODS: Using the Cervex-Brush, Papanicolaou smears were collected from 516 women in a prospective randomized study to evaluate five different clockwise rotation techniques: 180 degrees rotation of the brush, 360 degrees, 720 degrees, 1080 degrees, and 1800 degrees. The Bethesda System of classifying Papanicolaou smears was used to report cytologic results. Endocervical cell presence as an indicator of smear adequacy was quantitated from 0 to 4+. RESULTS: As the number of rotations was increased, the number of endocervical cells collected also increased (P less than .05). Abnormal epithelial cells were found in 22.3% of the smears obtained by rotating the brush 1080 degrees and 1800 degrees. This was compared with abnormal cells found in 8.2%, 4.5%, and 11.5% of the smears collected by rotating the brush 180 degrees, 360 degrees, and 720 degrees, respectively (P less than .001). Two smears that identified high-grade squamous intraepithelial lesions were collected using the 1800 degrees rotation. Unsatisfactory smears were obtained in 39 (7.5%) of the 516 smears. The percentage of slides containing hemorrhagic artifact was greatest (16.4%) in the 1800 degrees rotation group, but the likelihood of the Papanicolaou smear being considered unsatisfactory was not increased (P less than .05). CONCLUSIONS: Using a clockwise 1800 degrees rotation of the Cervex-Brush to obtain a Papanicolaou smear maximized the collection of endocervical cells, detected the greatest percentage of abnormal cells, and did not statistically exceed the acceptable limit for hemorrhagic artifact.

Influence of racial origin on admission rates of patients with suspected myocardial infarction in Birmingham.

All patients with suspected myocardial infarction admitted to hospital in four Birmingham health districts were studied to test the hypothesis that Asian patients would be overrepresented and Caribbean patients underrepresented compared with the indigenous population. One thousand four hundred and ninety six patients had a final diagnosis of myocardial infarction or severe angina pectoris. The relative risk of admission for Asian men compared with white men aged 45-64 years was 2.65 (95% confidence interval 2.20 to 3.19) and the risk for Asian men was high for both myocardial infarction and ischaemia when analysed separately. The relative risk of admission for Caribbean men compared with white men was 0.53 (95% CI 0.33 to 1.20). The relative risk for Asian women compared with white women in the same age group was 2.58 (95% CI 1.68 to 3.96), but this was due to an excess of admissions diagnosed as ischaemia rather than infarction in the Asian women. For Caribbean and white women the risk of admission was the same, although significantly fewer Caribbean women were admitted with myocardial infarction. The study was undertaken in 1986-87 and population data had to be derived from the 1981 census. The resident population changed in those five years and so the results were recalculated making allowances for these changes in the health districts involved. Based on these data the admission rate for Asian men with suspected myocardial infarction aged 45-64 was nearly twice that for white men (1.8): the relative risk of admission for Asian men compared with white men was 2.04 (95% CI 1.53 to 2.18). For Caribbean men the relative risk compared with white men was 0.45 (95% CI 0.29 to 0.71). For Asian women the relative risk of admission calculated from the adjusted census data resemble that in white women aged 45-64 years. The relative risk for admission with coronary heart disease in Asians is higher than expected work; one possible explanation for this is that the Asian population resident in the area under study was larger than estimated. The single major difference in risk factors was the high prevalence of diabetes mellitus in Asians (19.5% compared with 8.3% for white residents) but this did not wholly account for the excess of admissions from the Asian community.

Interaction between (plus or minus)-amphetamine and atropine on the rat cardiovascular system.

1. The effects of atropine on the pithed rat blood pressure after (+/-)-amphetamine depend on the pattern of the cardiovascular responses to the latter.2. If the pressor response to amphetamine is followed by oscillations of blood pressure and a reduction in pulse pressure or by a fall in blood pressure terminating in circulatory failure, atropine increases blood pressure, but if it is not followed by these patterns, atropine decreases blood pressure.3. The fall in blood pressure produced by atropine after amphetamine might be due to weak alpha-adrenoceptor blockade.