Trial of pyrethroid impregnated bednets in an area of Tanzania holoendemic for malaria. Part 2. Effects on the malaria vector population.

The malaria vector population consisted mainly of Anopheles gambiae s.s. with a small contribution from An. funestus and An. rivulorum. The mosquitoes coming to bite in bedrooms were monitored with light traps set beside untreated bednets. When impregnated bednets were provided for all the other beds in a village the Anopheles populations declined but the Culex quinquefasciatus populations were unaffected. The survival of An. gambiae (as measured by the mean number of ovarian dilatations) and the sporozoite rate declined following introduction of the nets and the estimated sporozoite inoculation rates into people not under their nets declined by more than 90%. The net introductions caused sharp declines in the number of mosquitoes resting indoors, but the evidence was inconclusive regarding diversion to outdoor resting, animal biting, earlier biting or outdoor biting. DDT spraying greatly reduced the Anopheles populations.     

Trial of pyrethroid impregnated bednets in an area of Tanzania holoendemic for malaria. Part 1. Operational methods and acceptability.

In five Tanzanian villages, nets impregnated with permethrin or lambdacyhalothrin were given out. The people received them enthusiastically and brought their nets for re-impregnation at six monthly intervals. Bioassays showed that the insecticidal power of permethrin impregnated nets remained adequate for six months unless the nets were washed. Nets with 30 mg lambdacyhalothrin/m2 retained high insecticidal power despite washing, but this dose caused temporary cold-like symptoms in those sleeping under freshly treated dry nets. Methods by which durable bednets might be made affordable by Tanzanian villagers are discussed.     

Chronic Fatigue: A Survey, Outcome Study and Proposals

Background:  Sample sizes in studies of childhood chronic fatigue remain small and there is a need to integrate research findings and establish common criteria.
Method:  This is a detailed report of 20 children with medically unexplained fatigue, referred to as Chronic Fatigue Syndrome (CFS). It includes an uncontrolled outcome study of treatment based on a pragmatic cognitive-behavioural model adapted for children at Great Ormond Street Hospital for Children.
Results:  The data revealed psychological distress at 30 times the prevalence found in the normal child population, with specific high-ranking symptoms, including headache, social withdrawal and decreased appetite. Onset tended to occur at 11 years of age with some earlier problems at school age, suggesting it might be possible to identify those most at risk. Follow-up demonstrated improvement in 87% of the sample (parental report), a significant increase in school attendance and a significant decrease in symptom severity. Factors associated with good outcome were short duration of fatigue (less than a year) and behaviours that tended to combat the cycle of avoidance, such as carefully planned home-tuition.
Conclusions:  Recording a comprehensive range of symptoms and factors facilitates comparisons within and between child studies. It is proposed that symptom severity is a particularly relevant measure for Chronic Fatigue Syndrome which is characterised by persisting symptoms.     

The scopolamine model of dementia: chronic transdermal administration

The transient impairments of memory produced by the muscarinic antagonist scopolamine have been adopted as a pharmacological model of Alzheimer-type dementia in normal volunteers. In this study we examined the effects of chronic (72 h) transdermal administration of scopolamine on memory, attention, sedation and visual function. The transdermal patches provided constant plasma levels of scopolamine for the duration of the study. Indices of the peripheral effects of scopolamine (visual near-point and pupil size) showed impairments that were sustained for 3 days. However, measures of sedation and memory revealed impairments that were maximal the day after patch application and which were no longer present 3 days after application. This pattern of results is discussed in relation to pharmacological modelling of Alzheimer's disease.     

The effects of scopolamine on retrieval from semantic memory

The effects of two doses of scopolamine (0.6 and 1.2 mg p.o.) on retrieval from semantic memory in normal young volunteers were examined using tests of verbal fluency and categorization latency. A visual contrast sensitivity test, which has previously shown a scopolamine-induced impairment at these doses (Broks et al., 1988), was also administered. In agreement with the work of Dunne (1990) and others, no evidence for a scopolamine deficit in semantic retrieval was found; in fact scopolamine improved letter fluency. However, scopolamine did produce the expected decrease in visual contrast sensitivity. The doses of scopolamine used here have also been shown to impair learning and attention (Broks et al., 1988). It is possible that earlier studies which found a scopolamine deficit on semantic retrieval, did so because they used elderly subjects and/or large drug doses.     

Alertness and psychomotor performance effects of the histamine-3 inverse agonist MK-0249 in obstructive sleep apnea patients on continuous positive airway pressure therapy with excessive daytime sleepiness: a randomized adaptive crossover study

Objectives

We aimed to evaluate the efficacy of the selective H3 receptor inverse agonist MK-0249 to treat excessive daytime sleepiness (EDS).

Methods

In this three-period, double-blind, crossover study, 125 patients (100 men, 25 women; mean age, 48.6 years) with obstructive sleep apnea receiving nasal continuous positive airway pressure therapy who had refractory EDS were randomized to 2 weeks each of daily MK-0249 (5, 8, 10, or 12 mg, adaptively assigned), modafinil 200 mg, and placebo. At baseline and after each treatment period, six maintenance of wakefulness tests (MWT) and Psychomotor Vigilance Tasks (PVT) were conducted at 2-h intervals, beginning 1 h postdose (∼09:00). The Epworth sleepiness scale (ESS), Clinical Global Impression of Severity (CGIS) and Digit Symbol Substitution Test (DSST) also were assessed. The primary end point was MWT sleep latency averaged over the first four time points (MWT-early).

Results

MWT-early mean change from baseline sleep latency at week 2 was 1.2 min for placebo, 2.1 min for MK-0249 (top two doses pooled; P > .05 vs placebo), and 5.9 min for modafinil (P ? .001 vs placebo). MK-0249 showed improvements vs placebo on secondary and exploratory end points of ESS, CGIS, PVT, and DSST. Insomnia adverse events (AEs) were greater for MK-0249 (combined doses, 17.5%) than for placebo (0.9%) or modafinil (1.8%).

Conclusion

MK-0249 did not significantly affect MWT sleep latency. However, the pattern of improvement on subjective ratings and psychomotor performance end points suggested that MK-0249 was associated with changes in aspects of cognition and performance not captured by the MWT.     

Correction to: Epilepsy related multimorbidity,polypharmacy and risks in adults with intellectual disabilities: a national study

Journal of Neurology -