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Biomedical subjects

F Petit

Publications and source records attributed to F Petit.

At least 55 records · Page 3Linked to original sources
PubMed1999

The pharmacological profile of a novel norpregnance progestin (trimegestone).

Trimegestone is a novel norpregnane progestin that is being developed, in combination with estradiol, for the treatment of menopausal symptoms. The pharmacological characteristics of trimegestone have been evaluated in both in vitro and in vivo test systems, and compared with reference progestins. Interaction with hormonal steroid receptors from animal tissues and with human recombinant receptors in vitro has demonstrated that trimegestone has a high specificity and potency for the progesterone receptor, no affinity for the estrogen receptor, and weak affinity for androgen, glucocorticoid and mineralocorticoid receptors. With respect to progestomimetic activity in vivo, trimegestone was more potent than reference progestins in the endometrial transformation test in the rabbit, preventing the uterotrophic effect of estradiol in the immature mouse bioassay, and had more effect on traumatic deciduoma formation and greater oral antiovulatory activity in the rat. In vivo, trimegestone effectively maintained pregnancy in the rat, but was devoid of any uterotrophic activity. Trimegestone showed no androgenic, glucocorticoid, antiglucocorticoid or mineralocorticoid activity, but did show some antiandrogenic and antimineralocorticoid activity at higher doses. Administration of trimegestone to ovariectomized rats, in combination with estradiol, inhibited the uterotrophic effects of estradiol. At doses up to 1 mg/kg intravenously and 30 mg/kg orally, trimegestone was not associated with any unwanted pharmacological effects. Overall, the results show trimegestone to have a favorable pharmacological profile with potent progestomimetic activity.

Administration, Oral↗
PubMed1999

[Sebaceus nevus of Jadassohn. Apropos of 62 surgically treated cases and review of the literature].

The analysis of 62 cases of nevus sebaceus of Jadassohn and the study of the literature allows to define the clinical and histo-pathologic features of this benign tumor. The massive development of sebaceous glands, papillomatous epidermal hyperplasia, and maturation of apocrines glands, are present in a considerable number of cases. The lesions occurred on the scalp, face, auricular area and neck and are usually present at birth as a yellowish orange area. At puberty, the lesion becomes yellow to dark-brown and is verrucoid and micronodular. Almost all are hair-deficit nevi, and the final stage is the development of secondary tumors of the skin within the lesion. The risk of degeneration in basal-cell carcinoma justifies systematic surgical treatment.

Adolescent↗
PubMed1999

[Unusual breast scars].

The authors report the case of an unusual form of skin tattoo, discovered on the breasts of a young woman, corresponding to several scars forming a symbolic image, performed deliberately with a burning object. This form of mutilation is called "branding". Imported from England, it is developing in France as a result of fashion, but its followers could one day regret the permanent scars left by this deep burn.

Adolescent↗
PubMed1999

[Who are the French plastic surgeons?].

Based on data from the national advice of the Conseil National de l'Ordre des Médecins (French Medical Board), the author found 654 plastic surgeons in France and classified them into five categories, demonstrating the increasing proportion of females in this specialty.

Female↗
PubMed1998

Detection of adenovirus in the waters of the Seine River estuary by nested-PCR.

Several systems for isolating viruses from environmental samples have been tested. The most promising method is based on genomic amplification. The authors attempted to detect adenovirus in nucleic-acid extracts from the Seine River estuary by a two-step amplification of a 220-bp segment of the conserved coding region of type 2 adenovirus hexon protein L3. The primers used in this study detected the most prevalent adenovirus serotypes in human disease in France, but not other virus strains or bacteria. The sensitivity of the nested polymerase chain reaction (PCR) amplification was estimated to be 10(2) copies of the adenovirus target sequence per ml of Seine River water. Nucleic-acid extracts from Seine River estuary waters were analysed and some tested positive for the presence of adenoviruses.

Adenoviridae↗
PubMed1998

Regulation of the expression of a gene encoding beta-endoglucanase secreted by Myxococcus xanthus during growth: role of genes involved in developmental regulation.

An endoglucanase, CelA, is secreted by Myxococcus xanthus only during exponential growth. The production of this enzyme is decreased by mutations in 5 different genes (Exc +/- phenotype), three of which correspond to asg genes which regulate the production of an early cell-to-cell signal in development. Transcription of celA is decreased in two of these Exc +/- mutants, whereas a post-transcriptional step is affected in two other Exc- mutants. Thus, asg genes, in addition to regulating the onset of development, also regulate a gene (celA) that is expressed during exponential growth and that is not involved in development.

Amino Acid Sequence↗
PubMed1998

[Late infection of breast implant, complication of colonic perforation. Review of the literature. Role of preventive treatment].

The authors report a cases of breast implant infection, 40 years after augmentation mammoplasty. The infection developed 6 weeks after colonoscopy complicated by acute peritonitis due to colonic perforation. Bacteroides fragilis, a usual organism of the gastrointestinal tract flora, was identified in the two septic sites (peritoneal and periprosthetic). Contamination of the implant was haematogenous in a context of bacteraemia. Other authors have already suspected this route of contamination without any bacteriological proof. The risk of infection of breast implants is known, but the late infection rate is poorly documented. It is probably very low in view of the rare cases reported in the literature. Breast implants are not at high risk of sepsis, in contrast with prosthetic heart valves. The authors therefore do not recommend any particular preventive treatment in the case of distant infection or dental treatment. Women with breast implants must be informed and reassured: late infection of their implant is possible, but very unlikely. Recognition and prevention of this risk could be based on better long-term follow-up of breast implants.

Aged↗
PubMed1997

Involvement of proteasomal subunits zeta and iota in RNA degradation.

We have identified two distinct subunits of 20 S proteasomes that are associated with RNase activity. Proteasome subunits zeta and iota, eluted from two-dimensional Western blots, hydrolysed tobacco mosaic virus RNA, whereas none of the other subunits degraded this substrate under the same conditions. Additionally, proteasomes were dissociated by 6 M urea, and subunit zeta, containing the highest RNase activity, was isolated by anion-exchange chromatography and gel filtration. Purified subunit zeta migrated as a single spot on two-dimensional PAGE with a molecular mass of approx. 28 kDa. Addition of anti-(subunit zeta) antibodies led to the co-precipitation of this proteasome subunit and nuclease activity. This is the first evidence that proteasomal alpha-type subunits are associated with an enzymic activity, and our results provide further evidence that proteasomes may be involved in cellular RNA metabolism.

Animals↗
PubMed1997

Proteasome (prosome) associated endonuclease activity.

The 20S proteasome (prosome) is a highly organized multiprotein complex with approximate molecular weight of about 700 kDa. Whilst the role of the proteasome in the processing and turnover of cellular proteins is becoming clearer, its relationship with RNA remains still obscure. Here we focus on the nature and function of proteasome associated endonuclease activity. Thus the involvement of a proteasome alpha-type subunit in RNA-degradation, the catalytic requirements, the interaction of proteasomes with their RNA-substrate and the identification of a well defined cleavage site in the 3'UTR of short-lived cellular mRNAs will be described in detail. All data indicate that proteasomes associated endonuclease activity could be involved in post-transcriptional gene control at the level of translation.

Animals↗
PubMed1997

Synthetic glucocorticoids that dissociate transactivation and AP-1 transrepression exhibit antiinflammatory activity in vivo.

Some of the most potent antiinflammatory and immunosuppressive agents are synthetic glucocorticoids. However, major side effects severely limit their therapeutic use. The development of improved glucocorticoid-based drugs will require the separation of beneficial from deleterious effects. One possibility toward this goal is to try to dissociate two main activities of glucocorticoids, i.e. transactivation and transrepression. Screening of a library of compounds using transactivation and AP-1 transrepression models in transiently transfected cells identified dissociated glucocorticoids, which exert strong AP-1 inhibition but little or no transactivation. Importantly, despite high ligand binding affinity, the prototypic dissociated compound, RU24858, acted as a weak agonist and did not efficiently antagonize dexamethasone-induced transcription in transfected cells. Similar results were obtained in hepatic HTC cells for the transactivation of the endogenous tyrosine amino transferase gene (TAT), which encodes one of the enzymes involved in the glucocorticoid-dependent stimulation of neoglucogenesis. To investigate whether dissociated glucocorticoids retained the antiinflammatory and immunosuppressive potential of classic glucocorticoids, several in vitro and in vivo models were used. Indeed, secretion of the proinflammatory lymphokine interleukin-1beta was severely inhibited by dissociated glucocorticoids in human monocytic THP 1 cells. Moreover, in two in vivo models, these compounds exerted an antiinflammatory and immunosuppressive activity as potent as that of the classic glucocorticoid prednisolone. These results may lead to an improvement of antiinflammatory and immunosuppressive therapies and provide a novel concept for drug discovery.

Animals↗
PubMed1997

Two complementary bioassays for screening the estrogenic potency of xenobiotics: recombinant yeast for trout estrogen receptor and trout hepatocyte cultures.

A relation between the chemical structure of a xenobiotic and its steroidal action has not yet been clearly established. Thus, it is not possible to define the estrogenic potency of different xenobiotics. An assessment may be accomplished by the use of different bioassays. We have previously developed a yeast system highly and stably expressing rainbow trout estrogen receptor (rtER) in order to analyze the biological activity of the receptor. The recombinant yeast system appears to be a reliable, rapid and sensitive bioassay for the screening and determination of the direct interaction between ER and estrogenic compounds. This system was used in parallel with a more elaborate biological system, trout hepatocyte aggregate cultures, to examine the estrogenic potency of a wide spectrum of chemicals commonly found in the environment. In hepatocyte cultures, the vitellogenin gene whose expression is principally dependent upon estradiol was used as a biomarker. Moreover, competitive binding assays were performed to determine direct interaction between rtER and xenobiotics. In our study, 50% of the 49 chemical compounds tested exhibited estrogenic activity in the two bioassays: the herbicide diclofop-methyl; the fungicides biphenyl, dodemorph, and triadimefon; the insecticides lindane, methyl parathion, chlordecone, dieldrin, and endosulfan; polychlorinated biphenyl mixtures; the plasticizers or detergents alkylphenols and phthalates; and phytoestrogens. To investigate further biphenyl estrogenic activity, its principal metabolites were also tested in both bioassays. Among these estrogenic compounds, 70% were able to activate rtER in yeast and hepatocytes with variable induction levels according to the system. Nevertheless, 30% of these estrogenic compounds exhibited estrogenic activity in only one of the bioassays, suggesting the implication of metabolites or different pathways in the activation of gene transcription. This paper shows that it is important to combine in vivo bioassays with in vitro approaches to elucidate the mechanism of xenoestrogen actions.

Animals↗
PubMed1997

[Isolated congenital diverticulum of the left ventricle disclosed by ventricular tachycardia in a 72-year-old woman].

A 72-year-old woman presented with poorly tolerated ventricular tachycardia reduced by intravenous amiodarone. The possibility of an ischaemic aetiology led us to perform coronary angiography. The coronary arteries were pathological. Left ventricular angiography revealed limited anterior hypokinesia and a large contractile apical pouch appended to the left ventricle by a long narrow neck. Despite the appearance suggestive of congenital left ventricular diverticulum (contractility, narrow neck) and because of the coexistence of ischaemic heart disease, we preferred to confirm the muscular nature of the diverticulum by myocardial thallium scintigraphy, which showed reversible decreased uptake in the anterior zone related to coronary artery disease, and confirmed the muscular nature of the diverticulum which showed normal thallium uptake. MRI clearly visualized the ventricular ectasia attached by a narrow neck to the rest the left ventricle. This long narrow neck indicated that this muscular diverticulum constituted a congenital diverticulum. The contribution of ultrasonography was limited by a poorly defined point during the examination. This congenital diverticulum, discover during adulthood, and previously asymptomatic, is a rare lesion, in the light of a review of the literature.

Aged↗
PubMed1996

Protection of rabbits against rabbit viral haemorrhagic disease with a vaccinia-RHDV recombinant virus.

In order to protect domestic and wild rabbits against RVHD, we constructed a recombinant vaccinia-RHDV virus, using the Copenhagen strain of the vaccinia virus. This recombinant virus expressed the RHDV capsid protein (VP60). Analysis of the expressed product showed that the recombinant protein, which is 60 kDa in size, was antigenic as revealed by its reactions in immunoprecipitation and indirect immunofluorescence with the antibodies raised against RHDV. The recombinant virus induced high level of RHDV specific antibodies in rabbits following immunization. Inoculations by both the intradermal and oral routes allow protection of animals against a challenge with virulent RHDV.

Administration, Oral↗
PubMed1996

Protection against myxomatosis and rabbit viral hemorrhagic disease with recombinant myxoma viruses expressing rabbit hemorrhagic disease virus capsid protein.

Two myxoma virus-rabbit hemorrhagic disease virus (RHDV) recombinant viruses were constructed with the SG33 strain of myxoma virus to protect rabbits against myxomatosis and rabbit viral hemorrhagic disease. These recombinant viruses expressed the RHDV capsid protein (VP60). The recombinant protein, which is 60 kDa in size, was antigenic, as revealed by its reaction in immunoprecipitation with antibodies raised against RHDV. Both recombinant viruses induced high levels of RHDV- and myxoma virus-specific antibodies in rabbits after immunization. Inoculations by the intradermal route protected animals against virulent RHDV and myxoma virus challenges.

Animals↗