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Biomedical subjects

A Lefevre

Publications and source records attributed to A Lefevre.

At least 19 recordsLinked to original sources
PubMed2005

[The place of routine immediate non-invasive ventilation following pulmonary resection in preventing pulmonary complications in patients with COPD (POPVNI Trial)].

BACKGROUND: Respiratory complications are common following pulmonary resection and cause a significant mortality. The use of non-invasive ventilation (NIV) in acute respiratory insufficiency (ARI) is now well recognised. The prophylactic use of NIV in the absence of ARI and/or hypercapnia may be equally justified for the physiological benefits expected in the post-operative period following pulmonary surgery. The aim of our study therefore is to evaluate the effectiveness of NIV in the prevention of pulmonary complications in the immediate post-operative care of patients with moderate and severe COPD. METHODS: It will be a multicentre, prospective, randomised, parallel, open ended study of patients with moderate and severe COPD admitted to hospital for pulmonary resection. EXPECTED RESULTS: To determine whether the setting up of NIV immediately post-operatively reduces the incidence of acute respiratory events (acute respiratory insufficiency) and to identify any sub-groups who receive greater benefit from NIV. This study should establish the place of NIV in the immediate post operative care following pulmonary resection.

Adult↗
PubMed2005

[Biodegradation of synthetic bioglasses with different crystallinity in vitro].

SG600, SG900 and SG1100 were synthesized by the sol-gel method. Further treatments with increasing temperatures influenced and determined the crystallization degree of the material. Primary cultured osteoclasts were incubated for 4h and 48h on samples. Osteoclast actin labeling was examined by cytochemical staining. The concentrations of Ca and P in culture medium were quantified by colorimetric methods. SEM examined osteoclast morphology and resorption lacuna. Actin staining revealed on all three materials the typical adhesion contact ring. The Ca concentration in the culture medium of SG600 was significantly higher than that in control medium, SG900 and SG1100. Ca and P concentrations were always higher in culture media with the presence of osteoclasts. Morphological studies by scanning electron microsopy(SEM) showed a good adhesion behavior of osteoclasts on all three samples. Well-developed and deep resorption lacunae appearing after the osteoclastic resorption action were detected on all three samples. The synthetic bioglasses with different crystallizations caused different solubility, which seemed to have little effect on the osteoclast resorption behavior. The results of morphological studies on osteoclasts and resorption lacunae clearly demonstrate that the synthetic bioglasses are easily resorbed in vitro by osteoclasts.

Absorbable Implants↗
PubMed1999

Cloning and characterization of SOB1, a new testis-specific cDNA encoding a human sperm protein probably involved in oocyte recognition.

A human sperm-oocyte binding protein, SOB1, was purified by two dimensional gel electrophoresis and sequenced. This protein was selected because it was recognized by a monoclonal antibody that inhibited the binding of human sperm to zona-free hamster oocytes. The sequences of the tryptic peptides were used to design degenerate primers. These were used to amplify a specific fragment from human testis cDNA by the polymerase chain reaction. This 1233 bp fragment was extended in 3' and 5' by RACE to obtain the 3 kb full length SOB1 cDNA. Sequence analysis indicated that the deduced open reading frame encodes a 853 amino acid protein, with a molecular mass of 94. 7 kDa. This is a new testis-specific cDNA. It is 27, 32.8 and 34.4% homologous to three sperm proteins, HI, Fsc1 and AKAP82 respectively. A single 3kb transcript was demonstrated only in the testis by northern blot analysis. It is a single copy gene, well conserved among mammals and located on human chromosome 12 at band p13.

A Kinase Anchor Proteins↗
PubMed1999

Motilin-producing liver and bone metastases evidenced 14 years after resection of a rectal polyp.

A 62-year-old man with a history of a resected rectal polyp was diagnosed 14 years later with right liver and multiple bone metastases. The liver biopsy showed a malignant epithelial tumor that was positive for neuron-specific enolase immunostaining and negative for chromogranin. Electron microscopy was characteristic of that for an endocrine tumor. Most circulating hormonal peptide levels were within normal ranges and only motilin level was elevated. On the right hepatectomy, the three large metastases had a histologic picture suggestive of an endocrine tumor. Immunohistochemistry revealed in some areas numerous tumor cells expressing motilin, and a few cells were strongly positive for pancreatic polypeptide and somatostatin. The retrospective analysis of the rectal polyp showed a similar histology and immunohistochemical profile, indicating that this lesion was the primary tumor. Motilin-positive cells from one of the hepatic lesions were identified on semithin sections and further processed for electron microscopy. Neurosecretory granules were numerous in all cells. Immunoelectron localization enabled us to characterize the motilin-containing neurosecretory granules, which had a mean diameter of 168.3x38.1 nm. Although not all tumor cells were motilin-positive, a diagnosis of motilinoma for the rectal polyp and its hepatic and bone metastases was proposed.

Biopsy↗
PubMed1998

Neonatal hyperinsulinemic hypoglycemia: heterogeneity of the syndrome and keys for differential diagnosis.

The two major forms of infantile persistent hyperinsulinemic hypoglycemia require different treatments, but are difficult to differentiate during surgery. Indeed, one is characterized by focal adenomatous hyperplasia often macroscopically invisible, whereas the other consists of a diffuse, but discreet, beta-cell abnormality. We evaluated, in a large series of persistent hyperinsulinemic hypoglycemia, the reliability of two criteria in differentiating these two forms: the mean beta-cell nuclear radius (MNR) and the beta-cell nuclear crowding, i.e. the number of nuclei per 1000 micron 2 beta-cell (BCNC). The values of the largest MNR and of BCNC in cases bearing a focal lesion (respectively, 3.27 microns +/- 0.25 and 14.62 +/- 1.78) were significantly different from those in the diffuse pathology (4.25 microns +/- 0.43 and 10.00 +/- 1.55). Setting the threshold value of MNR at 3.70 microns and that of BCNC at 12.00 enabled correct classification of 90.9% of the diffuse and 100% of the focal forms. beta-Cell nuclear analysis can thus contribute to a subclassification of the syndrome, not allowed by clinical or biological data. If performed during surgery it could help in determining the extent of pancreatectomy necessary to cure the patient, as the diffuse form, with abnormal nuclei in the whole pancreas, requires subtotal to near-total pancreatectomy, whereas the focal form, devoid of abnormal insular beta-cell nuclei, can be cured by partial pancreatectomy.

Cell Nucleus↗
PubMed1998

Focal transmural necrosis of the gallbladder with bleeding resulting in a massive haemoperitoneum.

A case of massive haemoperitoneum as a complication of focal transmural necrosis of the gallbladder with bleeding during acute cholecystitis is reported. Urgent laparotomy and cholecystectomy was performed to secure an adequate haemostasis. A review of the literature confirmed that this condition is a very rare complication of acute cholecystitis. Only 44 similar cases have been reported between 1858 and 1996. In our case, bleeding was caused by the edges of a necrotic zone in the gallbladder wall.

Acute Disease↗
PubMed1997

Laparoscopic repair of a Morgagni hernia.

The authors present a case of laparoscopic repair of a symptomatic Morgagni hernia in an adult patient. The indication for surgery was based on symptoms of dyspnea and sensation of thoracic tightness. A tension-free closure of the defect using a Marlex mesh was carried out. Recovery was quick and uneventful. One year after surgery, no complaints were noticed. Aetiology, diagnosis and treatment are discussed.

Aged↗
PubMed1997

[In vitro and in vivo biocompatibility of stainless steel as a function of surface treatments: roughness and surfacing with hydroxyapatite].

The in vitro tests on cell viability reveal a favorable position for steel and hydroxyapatite (HA)? However, the roughness induces a negative effect on cell proliferation. Sandblasting of the stainless steel considerably decreased cell number compared with the polished substrate. HA showed a better percentage of proliferation in spite of the surface effect compared with controls. For in vivo biocompatibility, intramuscular implants revealed localized inflammatory reactions for the HA treated stainless steel but nor for the untreated alloy.

Animals↗
PubMed1997

[Cytocompatibility of dental alloys containing palladium].

The cytoxicity and the 50% lethal concentration (LC50) has been assessed in vitro by the colony forming method in extracts of 5 precious or semiprecious alloys and of oxides and chlorides of the metal contained in these alloys: Pd, Ag, Cu, Zn, Sn, In and Ga. All alloy extracts in culture medium induced cell death depending on their composition. In, Ga and Sn compounds showed the most favorable cell viability, Cu and Ag salts induced the lowest survival rate.

Biocompatible Materials↗
PubMed1996

Ureteral stump metastasis from renal adenocarcinoma: case report and literature review.

The occurrence of metastasis along the ureteral stump after previous radical nephrectomy for renal adenocarcinoma is very rare, only 47 cases having been reported in the literature. We present a case of metastasis of renal adenocarcinoma, occurring in the ureteral remnant, more than three years after ipsilateral radical nephrectomy. The analysis of this and previously reported cases leads us to propose radical nephro-ureterectomy as treatment of choice in certain cases of renal adenocarcinoma, instead of radical nephrectomy alone, notably when preoperative urine-cytology shows the presence of adenocarcinoma cells, and/or when vascular tumor infiltration is present. This adjuvant surgical step is of course only justified in those cases where a reasonable life-expectancy is present at the time of diagnosis, and thus especially applicable in the smaller T2 tumor group.

Aged↗
PubMed1995

[Aids and chorioretinal opportunistic infections].

Retrospective study of 19 cases of opportunistic infections of the chorioretina in patients with the Acquired Immunodeficiency Syndrome. We observed 14 cases of CMV retinitis, 2 cases of toxoplasmic chorioretinitis, 1 case of cryptococcal choroiditis and 2 cases of herpes zoster retinitis. Review of the clinical, angiographical and histopathological aspects of these infections. Review of the vital and visual prognosis after treatment.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Comparison of 2 techniques for measuring lymphocyte proliferation: tritiated methyl-thymidine incorporation and propidium iodide fluorometry].

In vitro lymphocyte mitogenic stimulation by phytohemagglutinin A was determined in 20 subjects, comparing tritiated thymidine incorporation and nuclear propidium iodide fluorescence. Unexpectedly, no correlation could be found between the two measures. The pitfalls of both methods are reviewed and discussed. The inability to validate one test by the other restricts the interpretation of the results obtained with one method and prevents their generalization. Without another gold-standard at the present time, specific and limited method-dependent norms should be defined.

Fluorometry↗
PubMed1994

Thiobarbiturate and fructosamine assays: significance and interest of the borohydride blank.

The acute-phase reaction (APR) induces the production by the liver of short-lived glycoproteins. The carbohydrate moiety of these proteins is thought to interfere with the thiobarbiturate (TBA) and nitroblue tetrazolium colorimetric tests which are used for assaying non-enzymatic glycosylation (NEG) of serum proteins. The aim of the present study was to assess the effect of the APR on the specificity of the colorimetric tests in non-diabetic and diabetic subjects. A positive correlation was found between C-reactive protein (CRP), an APR glycoprotein, and non-specific TBA reactivity as determined after borohydride reduction (BH4-resistant TBA, BR-TBA), both in non-diabetics (r = 0.61; P < 0.01) and diabetics (r = 0.68; P < 0.01). The BH4-sensitive specific TBA (SP-TBA) was not influenced by glycoproteins, and its increase in diabetics was correlated with the nitroblue tetrazolium assay (r = 0.89; P < 0.01). An independent effect of diabetes and APR on non-specific TBA was also demonstrated, suggesting an effect of hyperglycaemia on both protein glycation and glycosylation. TBA with borohydride reduction is an attractive tool for the study of complex glycoproteins in diabetes.

Acute-Phase Reaction↗
PubMed1994

Interleukin-6 biosynthesis in human preovulatory follicles: some of its potential roles at ovulation.

In the present work we explored cellular sites of interleukin-6 (IL-6) biosynthesis in human follicular aspirates from patients undergoing in vitro fertilization therapy and the effects of this cytokine on oocyte fertilization and granulosa cell (GC) steroidogenesis. Biological IL-6 activity from 20-40 IU/mL was present in follicular fluids from 22 patients; it was also detected in 10 of 22 supernatants of cultured oocyte-cumulus complexes and in cumulus cell and GC cultures. Biological IL-6 activity in oocyte-cumulus complex cultures was not related to fertilization rates. Total ribonucleic acid was isolated from follicular aspirates and GC-enriched preparations. After reverse transcriptase and polymerase chain reaction cycles using oligonucleotide primers corresponding to known cDNA sequences for IL-6, a 126-basepair band characterized the amplification product of IL-6 transcripts on gel electrophoresis. To localize IL-6 messenger ribonucleic acid, in situ hybridization analysis was performed using a [35S]IL-6 riboprobe. The distribution of transcripts was more dense (15% vs. 3% stained cells) in GC-enriched preparations, which contained more than 95% GCs, than in original follicular preparations, which contained 20-40% viable GCs; it was not significantly modified by the presence of macrophage contaminants. The expression of IL-6 protein was assessed by positive immunohistological stainings. Biological IL-6 activity was higher, and in situ hybridization signals were more dense and more intense in 24-h GC cultures than in 72-h GC cultures, suggesting that IL-6 biosynthesis was transiently induced. Under experimental conditions of low IL-6 endogenous levels in cultures, adding recombinant human IL-6 from 10-200 IU/mL had no effect on progesterone production or aromatase activity in GC cultures free of macrophages, whereas in GC cultures including macrophage contaminants, stimulatory effects on basal and hCG-stimulated progesterone production and on basal and FSH-stimulated aromatase activities were observed. The present study provides strong support for the view that IL-6 is produced by GCs in the preovulatory follicle at the time of ovulation. In addition, we showed that IL-6 might be an intraovarian regulatory factor concerned with steroidogenesis.

Adult↗
PubMed1993

Hormonal status and clinical relevance of hirsutism in elderly women.

Hirsutism is a common condition of elderly women, but its aethiopathogeny and its clinical implications remain unclear. We therefore studied circulating androgen concentrations in elderly women. In addition, this study aims to define a possible relationship between hirsutism and anthropometric determinations, bone mass and serum lipids. Androgen levels were determined at basal state, after adrenocorticotrophin (ACTH) stimulation and after dexamethasone administration in 10 hirsute elderly women and compared to 10 age-matched non-hirsute women. Anthropometric determinations included measurements of skinfold thickness and body mass index. Spinal bone mass density was assessed using dual photon absorptiometry. Hirsute women presented significantly higher levels of testosterone than controls (1.49 +/- 0.38 vs 0.59 +/- 0.05 nmol/l, mean +/- SEM; p < 0.05) and dihydrotestosterone (0.54 +/- 0.07 vs 0.32 +/- 0.03; p < 0.02). 17-hydroxyprogesterone levels after ACTH stimulation tended to be higher in hirsute women than in controls. No differences were observed between the two groups in serum oestrogen concentrations, plasma lipid pattern or bone mineral density. Hirsute women had a lower body mass index and lower calculated percentage body fat than the control group. We conclude that: (i) hirsutism of elderly women is associated with increased androgen levels, probably from adrenal origin; (ii) in some cases, enhanced response in 17-hydroxyprogesterone after ACTH stimulation suggests a partial adrenal 21-hydroxylase deficiency; (iii) hirsute women present anthropometric characteristics compatible with the known anabolic effect of androgens on fat-free mass.

Adrenocorticotropic Hormone↗
PubMed1992

Human sperm proteins from testicular and epididymal origin that participate in fertilization: modulation of sperm binding to zona-free hamster oocytes, using monoclonal antibodies.

In order to identify human sperm surface proteins involved in the gamete recognition process, mouse monoclonal antibodies were directed against human spermatozoa and screened with live spermatozoa by enzyme-linked immunosorbent assay (ELISA). Immunoperoxidase staining of human testis showed the early presence of four corresponding proteins on germinal cells, while six were detected primarily in testis fluid. The presence of 17 proteins was evidenced in the epididymis. Eight were detected with a decreasing gradient from the beginning to the end of the organ, including vasa efferentia for three of them. The other nine were observed in only one defined segment, usually the caput epididymis, which was found to be the most active region. Comparison of spermatozoa patterns from testis, vasa efferentia, and the three regions of epididymis pointed out a progressive coating. By contrast, three antibodies displayed a migration of spermatozoa surface domains in the course of epididymal transit. Six antibodies were found to inhibit human spermatozoa adherence to zona-free hamster oocytes, while nine promoted it. Molecular weights of antigens corresponding to nine of the antibodies ranged from 11 to 215 kDa. No correlation could be established with previously described human proteins. These observations emphasize the role of epididymis in human sperm maturation.

Animals↗