In preparation for an ivermectin distribution programme, the prevalence and intensity of infection due to Onchocerca volvulus as well as the species composition and abundance of Simulium vectors were investigated in 22 Yanomami communities situated along 2 altitudinal transects in the southern Venezuelan onchocerciasis focus. These transects corresponded to the Ocamo-Putaco and Orinoco-Orinoquito river systems, covering a range of elevation between 50 m and 740 m above sea level (asl). A total of 831 people underwent parasitological examination in this survey and an additional 196 patients from a previous study, at an altitude of 950 m, were included in the analysis. A total of 92,659 man-biting blackflies were collected and identified to morphospecies. S. oyapockense s.l. was the predominant simuliid up to 150 m asl, whereas S. guianense s.l. and S. incrustatum s.l. prevailed above 150 m. Communities located below 150 m were found to range from hypo- to mesoendemic; all villages above 150 m proved to be hyperendemic (> 60% microfilarial prevalence) and mass ivermectin treatment should be implemented. Age above 10-14 years, altitude of the village and biting rate of S. guianense s.l. up to 200 m asl were found to be statistically significant independent predictors of infection by multivariate logistic regression using a spline model. There were no differences in infection status according to sex. Above 200 m, microfilarial rate and density remained approximately constant, prevalence averaging 79% regardless of blackfly abundance. For the implementation of ivermectin-based onchocerciasis control programmes in the Amazonian focus, altitude and species composition of the blackfly population might be adopted as useful indicators aiding selection of the most affected communities. However, below 200 m additional parasitological indicators may also be necessary. As a direct result of this study, regular mass-ivermectin delivery to meso- and hyperendemic communities is now in progress.

Adolescent↗

PubMedDate not supplied

Prolonged administration of cyclosporine A causes an increase in spontaneous contractile activity of the rat intestine.

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Animals↗

PubMedDate not supplied

[Family-oriented after-care as a means of rehabilitation and secondary prevention for children with cancer and their families].

In a prospective longitudinal study 44 families, where one child had a cancer disease, were questioned about the effect of family oriented change in the physical condition of the patients and their parents, improvement of the psychic state of health of the patients and their brothers and sisters, improvement of the measured depressive general attitude of the fathers and mothers and a positive change in the relationship between the spouses. Apart from the medical aftercare the spare-time and pedagogical offers of the clinics where the most appreciated and the most frequented by the parents and the children.

Adaptation, Psychological↗

PubMedDate not supplied

Towards optimum blurring in spiral tomography.

Attempts to increase the degree of blurring of nonfocused layers in tomography are inevitably associated with a worsening in the amount of artefactual detail introduced. A mathematical optimization technique has been employed to indicate how these conflicting characteristics may best be reconciled. The technique uses plausible definitions, based on the transfer function, of the effectiveness and the fidelity of the blurring, and generates a sequence of spread functions in which these two aspects are optimally combined.

Mathematics↗

PubMedDate not supplied

Ion channels in Madin-Darby canine kidney cells.

Ion channels in Madin-Darby canine kidney cells serve transepithelial chloride transport and probably cell volume regulation. Three distinct potassium channels and one anion channel have been revealed by patch clamp studies in Madin-Darby canine kidney cells. The potassium channels are activated by an increase in intracellular calcium activity. A number of hormones activate the potassium channels by an increase in intracellular calcium activity. However, under certain conditions the hormones hyperpolarize the cell membrane without increasing intracellular calcium activity sufficiently to activate the calcium-sensitive potassium channels. Thus, the hormones may activate potassium channels via another, as yet undefined, intracellular mechanism. The anion channel is stimulated by cAMP. Another factor modifying channel activity is cell volume: cell swelling leads probably to subsequent activation of potassium and anion channels. The net result is a variable transient hyperpolarization followed by a sustained depolarization of the cell membrane.

Animals↗