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Biomedical subjects

G Petit

Publications and source records attributed to G Petit.

98 records · Page 6Linked to original sources
PubMedDate not supplied

[Dipetalonema dessetae--Aedes aegypti: study of the infected adipose tissue (author's transl)].

Histological and ultrastructural study of the adipose tissue of Aedes aegypti has shown that infection with the filaria Dipetalonema dessetae locally induces a highly active synthesis of proteins (formation of ribosomes, endoplasmic reticulum and Golgi complexes, multiplication of mitochondria). This phenomenon appears similar to the effect of beta-ecdysone after the up-take of blood. Mosquitoes let to starve during the development of the filaria show a quick disappearance of storage substances (lipids and glycogen) and involution forms of the induced ergastoplasma (after seventh days only), so that the infected tissue degenerates and the development of the filaria is arrested.

Adipose Tissue↗
PubMedDate not supplied

[The Filaria Breinlia booliati in the Adedes togoi adipose tissue; comparison with the couple Dipetalonema dessetae-A. aegypti (author's transl)].

In the couple Filaria-vector Breinlia (Breinlia) booliati-Aedes (Finlaya) togoi, the changs observed in the parasited adipose tissue display large similarities with those recently observed in Dipetalonemia (Molinema) dessetae-Aedes (Stegomyia) aegypti: same syncitium organisation of parasited adipocytes, and local stimulation of protein synthesis. However, there is an essential difference between the two coules studied: the parasited adipous syncitium is not any more induced by a blood uptake in booliati-togoi, whereas this parasited tissue reacts like unparasited adipocytes in dessetae-aegypti. Analysis of crossed couples (booliati-aegypti and dessetae-togoi) demonstrates that these physiological properties are not linked to the vecotr but to the Filaria itself.

Adipose Tissue↗
PubMedDate not supplied

[Validity of the two species O. lienalis and O. gutturosa from bovines (author's transl)].

A new morphological analysis of the Onchocerca from the gastrosplenic ligament reveals characteristics confirming the validity of the species O. lienalis as distinct from the cervical Onchocerca, O. gutturosa. The dermic microfilaire of the two species have completely different distributions: the microfilariae of O. gutturosa are gathered in the cephalic region of Bovines while that of O. lienalis can be found in the umbilical region. Therefore we suspect strongly that the life cycle evolving in S. ornatum in England is that of O. lienalis and not of O. gutturosa as previously postulated; and we think that O. gutturosa is more likely to evolve in Culicoides than in Simulium.

Animals↗
PubMedDate not supplied

[Description of two new species and infective stages of filariae from the genus Litomosoides (author's transl)].

Two new species of Litomosoides were collected from the Rio state in the vicinity of Teresopolis (Brazil). L. petteri n. sp. is the first record of this genus in the Marsupial (Marmosa cinerea), it does not display any particularly primitive feature. L. legerae n. sp. from a Cricetidae (Oxymycterus quaestor) is characterized by two lateral cephalic spines. Both species undergo their development in Bdellonyssus bacoti. Infective stages have large and segmented buccal capsule, similar to that of Rhabditids. We consider the genus Litomosoides as a primitive line, fundamentally parasite of Chiroptera, which is secundarily adapted to various Mammals (captural phenomenon).

Animals↗
PubMedDate not supplied

[The filaria Dipetalonema dessetae: phenomena of regulation and parasite yield in the Aedes vector].

Numerical observations were made on the various steps of the cycle of Dipetalonema dessetae in Aedes aegypti: -- ingestion of microfilariae: the numbers of the ingested microfilariae correspond to a negative binomial distribution, but the over-dispersion is less important than in the Bancroft's filaria as observed by Pichon; in this last case the microfilariae are thicker and thus are more slowed in the capillari; -- crossing of the stomach wall: the "limitation" is caused by a precociously established stomacal barrier (2nd hour); however, this barrier is not perfect and allows some microfilariae to infiltrate; -- larval development and migration towards the head: in the well fed mosquitoes, all the microfilariae in the hemocoel reach the infective stage, but less rapidly in the heavily infected mosquitoes; 50 per cent of the microfilariae migrate towards the head, not depending with the level of infection. In this couple filaria-vector, the regulation of the transmission is depending nearly exclusively with the stomacal "limitation" and secondarily with different speeds of the development. The feeding of the mosquito -- preimago or adult -- is an essential factor for vector efficiency.

Adipose Tissue↗