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Biomedical subjects

G Parent

Publications and source records attributed to G Parent.

At least 37 records · Page 2Linked to original sources
PubMed1984

Influence of vitamin A on the immune response of Schistosoma mansoni-infected rats.

Nutritional (vitamin A levels, weights), parasitological (adult worm burden, count of eggs in liver, stool examination) and immunological (IgE serum levels, anti-Schistosoma mansoni antibodies, lymphocyte stimulation by concanavalin A and S. mansoni antigenic extract) parameters were studied in three groups of rats, a non-infected and normally fed control group, a S. mansoni-infected but normally fed group, and a S. mansoni-infected group with experimentally induced vitamin A deficiency. The number of worms was found significantly higher in the third (53 +/- 19) than in the second group (2 +/- 2) (p less than 0.001). There were many eggs in the liver surrounded by granulomatous reactions in the third group (399 +/- 73 epg liver). All stool examinations were negative. IgE levels and anti-S. mansoni antibody titres were significantly lower (p less than 0.001) in the third than in the second group. The concanavalin A lymphocyte stimulation indexes did not differ significantly between groups 2 and 3; the S. mansoni lymphocyte stimulation index was only significantly positive in group 3 (p less than 0.001). These results indicate a decrease in the humoral immune response without alteration of cellular immune response in vitamin A-deficient rats infected with S. mansoni.

Animals↗
PubMed1982

Absence of variation in facteur thymique sérique activity in moderately and severely malnourished Senegalese children.

Facteur thymique sérique activity was evaluated in relation to different types of malnutrition in Senegalese children aged 5 to 42 months. They were classified in four groups: controls, moderate malnutrition, marasmus, and kwashiorkor, according to anthropometric measurements and clinical examination. The two latter groups were characterized by very depressed levels of total protein, album in, transferrin and prealbumin, and by high cortisol concentrations. Zinc status was marginal in all children. Facteur thymique sérique activity, determined by the rosette assay, was normal in the malnourished patients suggesting that moderate as well as severe malnutrition is not necessarily associated with depressed levels of circulating thymic hormone. These results are discussed in relation to zinc status and infections.

Blood Proteins↗
PubMed1980

Vitamin A status of populations in three West African countries.

The results of food consumption surveys, epidemiological surveys (clinical and biochemical) undertaken in three sub-sahelian countries have established: - the existence of xerophthalmia in Upper Volta - a transitory vitamin A deficiency during the dry season in South Mali, without serious clinical signs - a good vitamin A status in Casamance, in South Senegal. A combined biochemical indicator which takes account of plasma carotenoids and vitamin A is recommended to assess the importance of vitamin A deficiency in a population.

Adolescent↗
PubMedDate not supplied

Spectroscopic study of the image formation in near-field microscopy, near an evanescent-homogeneous switching.

Near-field optical microscopes provide highly resolved images of various samples. However, images are difficult to interpret owing to their sensitivity to illumination conditions. Moreover, by contrast with classical microscopy, the near-field signal combines the contributions of evanescent and propagative modes. In this study, we present results of a spectroscopic study in near-field. Our purpose is to explain how a switching of one diffracted mode from homogeneous to evanescent can modify image formation. The main point is to establish a relation between the evanescence of one diffracted mode and the fringes that are often observed in near-field experimental images. Moreover, on a metallic sample, the possible occurrence of plasmon resonance contributes to image distortion in a mainly different way. We use a Fourier series Rayleigh 3D method to explain image formation.

Journal Article↗
PubMedDate not supplied

Surface imaging in near-field optical microscopy by using the fluorescence decay rate: a theoretical study.

In this paper, we study the fluorescence decay rate of a molecule above a corrugated interface, and particularly the variations of the decay rate as a function of the lateral position of the molecule. As a first step, one has to determine the field diffracted by a corrugated interface when the incident field is the field emitted by a dipole. For this purpose, we have used a perturbative Rayleigh method, and we show that the decay rate variations can be connected to the surface profile via a transfer function. Some numerical calculations of this transfer function and of decay rate variation images are presented for dielectric and metallic samples. The visibility of the theoretical images is up to 20% and, moreover, resolution of the images is good enough to use the fluorescence lifetime of molecules as signal in a life-time scanning near-field optical microscope. The technical problems are discussed briefly.

Journal Article↗
PubMedDate not supplied

Use of killed poliovirus vaccine in a routine immunization program in West Africa.

Combined diphtheria-tetanus-pertussis (DTP)-killed poliovirus vaccine was used (along with bacille Calmette-Guérin, measles, yellow fever, and smallpox vaccines) in a routine immunization program in a rural area of Senegal. A control group in a neighboring region received DTP vaccine without poliovirus vaccine. All immunizations were given at two sessions six months apart by a small mobile health team led by a nurse. Six months after the second dose of DTP-polio vaccine, 97.4%, 97.7%, and 90% of subjects two to eight months old at the start had detectable antibody to poliovirus types 1, 2, and 3, respectively. In the control group, 50%, 38%, and 80% of such subjects had antibody to poliovirus types 1, 2, and 3, respectively, acquired by natural infection during the study year. An average of 3.9 cases of paralytic poliomyelitis (range, one to 13) were observed annually at one dispensary in the test region from 1966 through 1979. From 1980 through 1982, since the immunization program has been in effect, only one case has been observed (in a nonimmunized child).

Africa, Western↗
PubMedDate not supplied

["CLAPSEN", a global approach to the rehabilitation of severe childhood malnutrition in Bolivia].

The "CLAPSEN" approach was developed at the Hospital Materno Infantil German Urquidi in Cochabamba, to provide a global response for the study and treatment of childhood malnutrition. "CLAPSEN" is short for Clinical, Laboratory, Anthropometry, Psychology, Sociology, Nursing (Enfermera in Spanish) and Nutritional care. Most of the malnourished children admitted to Cochabamba Hospital are from poor families, more than three quarters of whom have only recently arrived in the city. Acute malnutrition is just one of the manifestations of a generally unfavorable environment. Malnutrition should not be considered as a simple deficiency in energy, protein or micronutrients, but rather as a multi-deficiency syndrome, also involving a lack of basic health and social care. This study demonstrates that malnourished children display a considerable degree of psychological retardation and of immune system depression. After five weeks of rehabilitation, the children were considered to have recuperated physically, as assessed by anthropometry, but not psychologically, as assessed by the adapted Dewer Score, or immunologically, as shown by the size of the thymus or the extent of maturation of lymphocytes. This strategy was not designed as a long-term approach for treating malnutrition, but rather as a research project to characterize the children arriving at the hospital, to determine the reasons for their malnutrition and to identify strategies that could be implemented earlier by health centers of social services, to prevent deterioration in the condition of these children to severe malnutrition requiring hospital admission. We believe that, in this Latin American context, in which the rate of acute malnutrition is low, the hospital should continue to be involved in the treatment of severely malnourished children with associated diseases. The child's stay in hospital should be short and once the child has recovered clinically, he should be sent home. In light of the observed levels of social deprivation, psychosocial and immune deficits, there appears to be a need for continued support for the family, to ensure the full recovery of the child and to prevent relapses.

Bolivia↗
PubMedDate not supplied

[Antigenic specificity of antiplasmodium antibodies in an endemic area: an attempt at correlation with the induction of protective immunity].

Asexual blood-stage antigens from Plasmodium falciparum related to the development of protective immunity in an endemic area were identified by statistical comparison of antigens recognized by adult immune sera with those recognized by non-immune subjects (children). After metabolic labelling of parasites in culture and immunoprecipitation, target antigens of seric antibodies were separated by polyacrylamide gel electrophoresis/SDS and detected by fluorography. Two groups of antigens were thus identified: 1) the major bands, recognized by more than 90% of the sera regardless of the patients' immune status; and 2) the minor bands, less intense on fluorograms. The corresponding antibodies were more frequent in children who had not yet acquired protective immunity than in immune adults. Thus, these minor bands do not appear essential for protection, which might instead be related to the presence of some major antigens, such as 210/196-, 136-, 121- and 80-Kd antigens. These antibodies persist for at least one year, independently of fluctuations in the rate of transmission by Anopheles.

Adult↗