Changes in the visceral functions of Plasmodium berghei-infected and -uninfected rats following administration of artemether.

1. The effects of artemether (12.5, 25.0 and 50.0 mg/kg per day, i.m.), administered to different groups of Plasmodium berghei-infected and -uninfected adult Wistar rats for 1 week, were investigated. 2. The parameters evaluated were the feeding, drinking and urinating patterns of the rats and these were compared with those of rats that received normal saline. 3. Artemether caused a significant dose-dependent reduction in food consumption of both P. berghei-infected and -uninfected rats (P < 0.05). Food intake in infected rats was reduced by approximately 7 g/24 h. This reduction in food intake was further reduced during drug treatment with artemether. Artermether also reduced food intake in uninfected rats. The food consumption of rats that received 12.5 and 25.0 mg/kg artemether was restored after stopping treatment, in contrast with rats that received 50.0 mg/kg, in which the significant reduction in food consumption persisted 1 week after drug administration. 4. During treatment with artemether, the water intake of infected rats was significantly lower than that of uninfected rats in the 12.5 mg/kg artemether-treated group, but was significantly higher in infected rats than in uninfected rats dosed with 25.0 and 50.0 mg/kg artemether. 5. For all doses of artemether tested, a significant increase in urine output was observed in infected rats during treatment and 1 week after treatment, whereas in uninfected rats a significant increase in urine output was observed only following 25.0 and 50.0 mg/kg artemether 1 week after drug administration. 6. The present study confirms the anorexic activity of a high dose of artemether in both P. berghei-infected and -uninfected rats. It also indicates that high doses of the drug could cause impaired renal function in rats and that the significant increase in urine output could also be due to other effects of artemether, namely those on thirst, anti-diuretic hormone output and the osmotic pressure of the blood.

An in vitro study of the effects of Cassia podocarpa fruit on the intestinal motility of rats.

Folkloric evidence and scientific reports indicate the use of C. podocarpa fruit as a purgative recipe. This study attempts to find the in vitro effects of its aqueous infusion (ACPF) and methanolic extract (MCPF) on the motility of the intestine of albino rats of Wistar strain and to compare their effect with those of C. acutifolia fruit (ACAF and MCAF). MCPF relaxed both the ileum and colon dose dependently. Its effect was blocked by tolazoline (10(-9) M) and propranolol (10(-9) M). ACPF had no effect on the ileum, but contracted the colon dose-dependently. Its effect was blocked by nifedipine (2.8 x 10(-10) M) and drastically reduced by atropine (3.4 x 10(-6) M). MCAF has the same effect as ACPF on both ileum and colon and its effect was similarly affected by atropine (3.4 x 10(-6) M) and nifedipine (2.8 x 10(-8) M). ACAF relaxed the ileum, its effect was blocked by tolazoline (5.1 x 10(-7) M). MCAF was more potent than ACPF in contracting the colon, Hexamethonium (2.8 x 10(-8) M), chlorpheniramine (3.8 x 10(-8) M) and promethazine (3.2 x 10(-10) M) potentiated the effect of ACPF on the colon. The results suggest that both ACAF and MCPF have anti-diarrhoeal effect. MCPF acts via both alpha and beta adrenergic receptor stimulation, while ACAF stimulates alpha-receptor. ACPF and MCAF engage both the cholinergic system and calcium channel activation in causing purgation in the colon. The potentiation of the effect of ACPF by some blockers could be due to allosteric enhancement of the receptors involved in its action.

Peripartum cardiac failure. A ten year follow-up study.

A cohort of patients with peripartum cardiac failure (PPCF) was followed for 10 years after the initial illness. The follow up rate was 78%. Fifty two per cent of patients improved without further episodes of heart failure. PPCF recurred in 26 per cent. Heart failure unrelated to pregnancy was seen in 13%, and 9% of the patients progressed to dilated cardiomyopathy. Transient hypertension was seen in 87% of patients on admission, and later hypertension was found in 45%. Late hypertension influenced heart size more when recurrent PPCF or progressive heart failure was present. Anaemia on admission had no effect on subsequent heart size. The electrocardiogram may continue to be abnormal for up to 10 years in normotensive patients who had no heart failure. The abnormal electrocardiogram in patients with persistent cardiomegaly may represent progressive myocardial damage. Mortality rate was highest (11%) in the first year and declined thereafter. Cardiac deaths were common in patients with recurrent PPCF or progressive heart failure.

Acute effect of cigarette smoking on peak expiratory flow rate and ventilation in resting Nigerian subjects.

The effects of cigarette smoking on peak expiratory flow rate (PEFR) and ventilation (V) in resting Nigerian subjects had been investigated in healthy male subjects (10 smokers, 8 non-smokers). The PEFR, V and tidal volume (VT) decreased significantly after smoking two medium-tar cigarettes. The action of smoke particles (carbon and tar) on the irritant receptor reflex of the lung, thus producing bronchoconstriction, and the depressant action of nicotine on the peripheral chemoreceptors, central chemoreceptors and respiratory centre may be the causal factors.

The effects of increasing pulmonary stretch and posture on sinus arrhythmia.

1. It is generally accepted that sinus arrhythmia is due to change in vagal tone and that it is only present when vagal tone to the sino-atrial node predominates over sympathetic tone. Arguments persist about the origin of the feed-back information which initiates the arrhythmia, mostly among supporters of stretch receptors in the lungs and thorax (Anrep et al., 1936; Clynes, 1960), and baroreflexes in the blood vessels (Bainbridge, 1920; Davies and Neilson, 1967; Adeoshun, 1976). 2. The literature is scanty about the genesis of sinus arrhythmia. It would be worthwhile to investigate sinus arrhythmia under varying tidal volumes and posture. With this procedure it might be possible to differentiate between the importance of extrathoracic blood vessel stretch receptors and lung stretch receptors in the genesis of the arrhythmia. 3. This study is designed to investigate some of the causal factors involved in the production of sinus arrhythmia.

Ventilatory pattern following diazepam and lorazepam.

The effect of intravenous diazepam (10 mg) or lorazepam (2 mg) on the ventilatory pattern has been studied in two groups of ten patients prior to elective surgery. Injection of lorazepam was followed by a periodic pattern of ventilation in nine patients.