Biomedical subjects

A Theron

Publications and source records attributed to A Theron.

40 records · Page 3Linked to original sources

PubMedDate not supplied

[Intestinal schistosomiasis in the freshwater mangrove of Guadalupe (French Antilles). Ecology of the vector, Biomphalaria glabrata and its parasite Schistosoma mansoni (author's transl)].

In the freshwater mangrove of Dubelloy-Devarieux (Guadalupe), the dynamics of populations of B. glabrata and the transmission of S. mansoni, mostly depends on the alternation of dry and rainy season. The flooding of the mangrove (in september), permits a yearly renewal of the malacological populations. The sizes analysis of the snails shows that the life cycle of B. glabrata include two rainy seasons separated by one dry season. The prevalence of B. glabrata (0,25%) and cercariae densities (0,8 c/l) are very slow. The acrophase of the rhythm of presence in standing waters is reached at 2 pm. Men and rats are infected. The infections of rats is of 20% at the beginning of the rainy season and of 100% at the end of the rainy season. Principal factors involved in the infection of rats are discussed.

Animals↗

PubMedDate not supplied

Chemoprophylaxis with erythromycin stearate or amoxycillin in patients with chronic bronchitis--effects on cellular and humoral immune functions.

Twenty-six patients aged between 27 and 71 years with chronic bronchitis were divided into a control group of 6 and two groups of 10 patients each who received either erythromycin stearate or amoxycillin 1500 mg/d for 2 weeks and 1000 mg/d for 12 weeks thereafter. Immunological function tests were performed before starting chemotherapy and thereafter at 2 weeks and 14 weeks. Clinical evaluations and lung function tests showed no significant changes in any of the groups during the study period. In the control group no changes in cellular and humoral immune functions were noted. In the group receiving amoxycillin decreased responses of lymphocytes to the mitogen phytohaemagglutinin were observed after 14 days. In the erythromycin-treated group, increased polymorphonuclear leucocyte (PMNL) motility and mitogen-induced transformation were observed at 14 days but these increases were not statistically significant. In this group the markedly depressed PMNL migration found in 3 individuals before treatment improved considerably. These results indicate that chemotherapy and chemoprophylaxis with either amoxycillin or erythromycin stearate do not compromise the host immunodefences.

Adult↗

PubMedDate not supplied

[An ecological approach to the problem of the responsibility of men and rats in the workings of a transmission site of Schistosoma mansoni in Guadeloupe (Western Indies) (author's transl)].

The study of the rate of contamination of B. glabrata and the cercarial densities of S. mansoni in the chanels of Beaugendre valley (Guadeloupe, French West Indies) concentrates attention on the focalisation of the sites with high risk of contamination. This focalization of the sites of transmission is directly related to the regular deposition of human faeces. A small number of contamined people is enough to maintain high cercarial densities (230 c/1). In the chanel studied, the role of the rat in the transmission of the parasite seems less important than that of the Man. The infection of the rats during consumption of snails can be foreseen.

Animals↗

PubMedDate not supplied

[Factors responsible for cercarial concentration of schistosoma mansoni in Guadeloupe].

Research carried out in Guadeloupe on the sites of transmission of Schistosoma mansoni shows that the circadian evolution of the cercarial concentration (rhythm of presence) differs slightly according to the biotope:--in a running water habitat (greater than 0,10 m/s) the rhythm of presence is superimposed on the rhythm of emergence, which leads to a risk of contamination reaching a maximum between 11 a.m. and noon; --in a slow running water habitat (around 0,01 m/s), the acrophase of the rhythm of presence is clearly retarded in comparison with that of the rhythm of emergence. In this case, the risk of contamination is greatest between 2 p.m. and 5 p.m. because of the accumulation of cercariae. The absolute value of the cercarial concentration in running water results from two antagonistic processes: production of cercariae depending on the amount of Biomphalaria glabrata infected and dilution of cercariae depending on the flow rate of water. Thus along one channel the cercarial concentration shows great variation depending upon which of the above processes predominates. These results demonstrate that the risk of human contamination can never be directly deduced from the demography of vectors.

Animals↗