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Biomedical subjects

A Petit

Publications and source records attributed to A Petit.

At least 163 records · Page 9Linked to original sources
PubMed1982

[Aortic insufficiency associated with ventricular septal defect and a coronary-right ventricle fistula after bacterial endocarditis: surgical correction of 3 lesions].

The authors report a case of Staph-aureus endocarditis on preexisting aortic incompetence. Two complications were observed during the course of the infection: ventricular septal defect, rare but classical, and coronary-right ventricular fistula, a complication not previously described to the best of the author's knowledge. Before the onset of endocarditis a continuous murmur had not been detected clinically or by phonocardiography. This sign appeared while the patient was receiving effective antibiotic therapy. The diagnosis, suggested by the clinical signs in a patient in cardiac failure, was confirmed by catheterisation. This type of complication, already described in peripheral vessels, may be understood when the extent of the lesions at the right coronary cusp, near the septum and right coronary ostium, are appreciated. A good surgical result was obtained due to early operation of the three lesions.

Aortic Valve Insufficiency↗
PubMed1981

Self-curve and immunity following infection and reinfection in ovine haemonchosis.

Egg expulsion and post mortem examination were used to compare self-cure and resistance to reinfection with Haemonchus contortus in female Merino sheep, AA and BB hemoglobin types. Animals were infected by 500 or 5000 larvae of H. contortus once, or several times, before being challenged by 500 (low dose) or 500 (high dose) larvae. In AA sheep infected once by 500 larvae self-cure was detected by a challenge of either 500 or 5000 larvae while in multi-infected sheep only a challenge of 5000 L, induced the self-cure. In BB sheep a mild self-cure was detected only by a challenge of 5000 larvae. In AA sheep receiving several infections, challenge by 500 larvae was not effective in producing resistance while 5000 L3 was effective in producing a state of resistance for up to 35 days post challenge. At post mortem examination, a strong state of resistance was evidenced in multi-infected animals by the low number of L4 and adults present in the abomasum up to the 35th day after challenge. In BB sheep no state of resistance was demonstrated by challenge with either 500 or 5000 L3, even in multi-infected animals.

Abomasum↗
PubMed1981

[Irregular anti-P1 allo-antibodies and sinensis clonorchiasis].

A parasitological and immuno-hematological study was undertaken simultaneously in fifty South-East asian refugees at the time of their arrival in France. --in this series the frequency of individuals having a P2 erythrocyte phenotype is 80%. --54 % of these immigrants were found to be carriers of Clonorchis sinensis, a parasite rarely found in Europe. --in 40,7 % of these subjects infested by Clonorchis sinensis, the following properties were disclosed concerning the P1 allo-antibody: slow-P1 red cell agglutination at 22 degrees C, no hemolysis of P1 red cells in vitro, IgM antibody, in weak titers. The immuno-hematological study of the immuno-serums with respect to distomian antigens coupled with adsorption-elution using P1+++ red cells shows a close immunological relationship between the antibody of parasite origin and the anti-P1 allo-antibody.

Anthelmintics↗
PubMed1981

[Feminizing action of dehydroepiandrosterone on the left testis of the chick embryo: ultrastructural aspect].

Chick embryos were injected with 4 X 0.5 mg of dehydroepiandrosterone from day 4 onwards and the ultrastructure of the 20-day old hormone-treated male gonads was studied. The cortex was well-developed and some oocytes had reached the meiotic prophase stage. The prefollicular cells did not seem to be stimulated by the androgenic hormone. We especially studied the seminiferous cords with Sertoli cells. Dense core granules, which might be related to secretory activity, were observed in the basal part of the Sertoli cells. The extensive development of smooth endoplasmic reticulum vesicles suggested that some Sertoli cells might have a steroidogenic function. The interstitial cells did not show an important steroidogenic synthesis. The action of dehydroepiandrosterone, which could induce the development of an ovarian-like cortex in intersexual gonads, is discussed.

Animals↗
PubMed1981

Circulating antigens in ovine haemonchosis.

We have developed a sandwich enzyme linked immunosorbent assay (sandwich ELISA), which allows the sensitive assay of Haemonchus contortus antigens. Using this test we have attempted to detect H. contortus circulating antigens in the serum, urine and milk of experimentally infected ewes. The results of this study indicate that circulating antigens may not be a general feature in ovine haemonchosis.

Animals↗
PubMed1980

Agropine in "null-type" crown gall tumors: Evidence for generality of the opine concept.

Agrobacterium Ti (tumor-inducing) plasmids, the causative agents of crown gall disease, fall into four genetic groups based on the patterns of octopine and nopaline synthesis (by crown gall tumors) and catabolism (by Agrobacterium tumefaciens) for which they are responsible. Two classes of Ti plasmids induce tumors that synthesize neither octopine nor nopaline. The existence of these Ti plasmids challenged the view that opines such as octopine and nopaline play a central role in crown gall biology. We now report the occurrence of an opine in tumors induced by one of these classes of Ti plasmids, the "null-type" plasmids typified by pTi Bo542. The opine was purified by biological enrichment based on its utilization by bacteria containing pTi Bo542 but not by bacteria lacking a Ti plasmid. The mass spectrum and biological properties of this opine are identical to those of agropine, an opine recently discovered in octopine-type tumors. We propose that null-type Ti plasmids now be named for their signal opine, agropine-type Ti plasmids.

Journal Article↗
PubMed1978

The performance appraisal process: a model and some testable propositions.

A literature-based model of the determinants of the accuracy of performance ratings is presented. The model indicates that the major determinants of accuracy are: (a) rater motivation; (b) rater ability; and (c) availability of appropriate judgmental norms. Several propositions and suggestions for further research are derived from the components of the model.

Employee Performance Appraisal↗
PubMed1977

[Neurosensitive contacts and new kind of synapses in wall lizard (Lacerta muralis, Laurenti) pineal body].

The neurosensitive synapses between photoreceptor cells and nerve ganglion cells are numerous enough to constitute an additional argument for a photosensitive function of the pineal gland. A new type of synapse, observed between the secretory rudimentary photoreceptor cells and nerve ganglion cells presents a direct relation from cells showing an active secretory function to the central nervous system.

Animals↗
PubMed1977

Thermosensitive step associated with transfer of the Ti plasmid during conjugation: Possible relation to transformation in crown gall.

It is reported here that transfer by means of a conjugative process of an oncogenic plasmid from a virulent strain of Agrobacterium tumefaciens to a strain of that organism that had been cured of the plasmid is thermosensitive. Since the thermosensitive step found in the conjugative process appears similar in every respect to a thermosensitive step that is involved in the transformation of a normal cell to a tumor cell in the crown gall disease of plants, it is suggested that the observed results may reflect the existence of a thermosensitive step that is common to these two processes.

Journal Article↗
PubMed1975

[Effect of injection of a phosphorylcholine-containing compound from Nippostrongylus brasiliensis on the infestation of the rat by this parasite].

Rats were injected intradermally with the purified phosphorycholine bearing component of the nematode Nippostrongylus brasiliensis. Eight days later they were experimentally infected with 1 X 10(3) infective larvae of the parasite. Compared to the non injected controls we showed a significant decrease in the number of adult worms able to be established in the small intestine. This protective effect seems to be due at least partly to a phenomenom being located between the skin and the lungs of the rats.

Ancylostomatoidea↗