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Biomedical subjects

F François

Publications and source records attributed to F François.

At least 19 recordsLinked to original sources
PubMed2001

A population of PC12 cells that is initiating apoptosis can be rescued by nerve growth factor.

Programmed cell death, or apoptosis, occurs asynchronously in neuronal cells. To overcome this asynchrony, rat pheochromocytoma (PC12) cells were separated at different stages of apoptosis on the basis of cell density. Live cells that exhibited no apoptotic features floated to the top of density gradients. The most dense cells showed extensive loss of cytochrome c from mitochondria, caspase activation, chromatin condensation, and DNA fragmentation. These cells were committed to apoptosis and could not be rescued by reculturing in with nerve growth factor (NGF). Cells of intermediate density displayed no DNA fragmentation, but had begun to show cytochrome c loss, caspase activation, and chromatin condensation. This population displayed upregulation of the prodeath factor, c-Jun, and downregulation of prosurvival kinase, Akt. Importantly, apoptosis was reversible by NGF in this population. These studies suggest that increased cell density correlates with an initial step in the apoptosis mechanism that precedes irreversible commitment to suicide.

Animals↗
PubMed2001

Alternative identification test relying upon sexual reproductive abilities of Candida lusitaniae strains isolated from hospitalized patients.

The in vitro mating ability of Candida lusitaniae (teleomorph Clavispora lusitaniae) clinical isolates has been investigated. Studying the effects of culture conditions, we showed that ammonium ion depletion in the medium is a major trigger of the sexual cycle. Moreover, a solid support is required for mating, suggesting a role for adhesion factors in addition to the mating type gene recognition function. Monitoring of mating and meiosis efficiency with auxotrophic strains showed great variations in ascospore yields, which appeared to be strain and temperature dependent, with an optimal range of 18 to 28 degrees C. The morphogenetic events taking place from mating to ascospore release were studied by scanning and electron microscopy, and the ultrastructure of the conjugation canal, through which intercellular nuclear exchanges occur, was revealed. Labeling experiments with a lectin-fluorochrome system revealed that the nuclear transfer was predominantly polarized, thus allowing a distinction between the nucleus donor and the nucleus acceptor strains. The direction of the transfer depended on the strain combination used, rather than on the genotypes of the strains, and did not appear to be controlled by the mating type genes. Finally, we demonstrated that all of the 76 clinical isolates used in this study were able to reproduce sexually when mated with an opposite mating type strain, and we identified a 1:1 MATa/MATalpha ratio in the collection. These results support the idea that there is no anamorph state in C. lusitaniae. Accordingly, the mating type test, which is easy to use and can usually be completed within 48 h, is a reliable alternative identification system for C. lusitaniae.

Candida↗
PubMed2001

[ A registry of ischaemic cardiopathies among active workers at Electricité de France-Gaz de France. Program development and first results].

BACKGROUND: The social security department of the French national electric and gas company has established an ischemic heart disease register among a population of about 140 000 employees based on sick leaves as well as deaths recorded with their medical cause. METHODS: History of the illness, medical tests and treatments were known retrospectively from the consulting physicians of the company. Acute coronary events recorded were: inaugural angina pectoris, myocardial infarction, sudden coronary death and fortuitous discovery of coronary disease. RESULTS: A first study conducted on employees during the 1993-1995 period showed infarction incidence age rates similar to those estimated from the French MONICA registers for France as a whole. Regional discrepancies were observed for myocardial infarction rates: Nord-Pas de Calais, Champagne-Ardennes, Lorraine, Franche-Comté and Limousin were at the most elevated risk (SIR=131, 155, 169, 125 and 178 resp). Large variations according to socio-economic status were observed. CONCLUSION: This register will permit studies on the links between socio-economic status at different professional career points and the occurrence of ischemic heart disease and the evaluation of the impact of psychosocial factors such as previous depressive disorders.

Absenteeism↗
PubMed2001

[Peri-aortic fibrosis: unusual case of jaundice].

Periaortic fibrosis is defined as the development of aortic perianeuvrysmal fibrosis either resulting from a focal inflammatory reaction or a self-perpetuating process. Compression of neighboring organs is a possible complication. Bile duct obstruction is exceptional.

Aorta, Abdominal↗
PubMed2000

CREB is cleaved by caspases during neural cell apoptosis.

Programmed cell death, or apoptosis, is a tightly regulated process mediated by selective cleavage of proteins by caspases, resulting in ordered destruction of the cell. In addition to structural proteins, proteins that mediate anti-apoptotic signal transduction are also substrates; their destruction eliminates potential futile attempts to escape execution. We asked whether cAMP response element binding protein (CREB), a transcription factor that mediates nerve growth factor (NGF) survival signals, is a target for caspases during apoptosis. CREB was specifically cleaved by caspases in neuroblastoma extracts, and in cells induced to undergo apoptosis by staurosporine. The destruction of CREB eliminates a key factor that could reverse apoptosis.

Adenosine Triphosphate↗
PubMed1999

Reporter cell lines to study the estrogenic effects of xenoestrogens.

In order to characterize the estrogenic activity of chemicals, we established complementary in vitro recombinant receptor-reporter gene assays in stably transfected MCF-7 and HeLa cells. MCF-7 cells which express the endogenous estrogen receptor alpha (ER alpha) were stably transfected with only an estrogen-regulated luciferase gene. These cells enable the detection of compounds which bind to ER alpha or interfere with the induction of ER alpha mediated gene expression. Furthermore, HeLa cells, which do not express endogenous ERs, were transfected with an ER alpha or an ER beta construct together with an estrogen-regulated luciferase gene, or a chimeric GAL4-ER alpha receptor and the corresponding luciferase reporter gene. Finally, we tested these four cellular models as tools to check the estrogenic activities of several potential xenoestrogens and to detect estrogenic activity in wastewater sewage treatment effluents. In all of the models, nonylphenol mixture (NPm), 4n-nonylphenol (4nNP), 2,4'-DDE, 4,4'-DDE and wastewater sewage treatment effluent were active, while PCB mixture (Aroclor 1254), PCB 77, atrazine and lindane (gamma hexachlorocyclohexane) were inactive. Dioxin partially activates the estrogen receptor in MCF-7 cells while in HeLa-derived cell lines, it decreased the estrogenic-induced expression of luciferase.

Cell Line↗
PubMed1999

Phosphorylation-dependent Akt cleavage in neural cell in vitro reconstitution of apoptosis.

Neuronal apoptotic execution uses a cytochrome c-dependent caspase activation mechanism that is conserved in other cell types. Phosphatidylinositol 3-kinase and its downstream effector, Akt/protein kinase B, appear to control this mechanism and govern the life/death decision. We have developed a cell-free system using cytosol from human neuroblastoma (SY5Y) cells that reconstitutes biochemical features of neuronal apoptosis. In the presence of cytochrome c and ATP, caspase-9 and -3 were activated, which initiated chromatin condensation and DNA cleavage in rat pheochromocytoma (PC12) nuclei. Akt was cleaved in reactions where caspase-3 was activated and its cleavage was prevented by the caspase inhibitor DEVD-aldehyde. The phosphatase inhibitors orthovanadate and okadaic acid prevented catalytic processing and activation of caspase-3 and digestion of Akt and partially inhibited cleavage of caspase-9. Caspase-dependent destruction of Akt irreversibly inactivates this key mediator of survival signaling, ensuring that the execution pathway will prevail.

Adenosine Triphosphate↗
PubMed1994

[What is to be done in the absence of a superficial venous network compatible with the creation of an arteriovenous shunt?].

When the utilization of a simple arteriovenous fistula is out of the question, or no longer practicable, several alternative solutions have been advocated. Our own experience of surgery rests on 3000 vascular operations on dialysis patients since 1968. The solutions we have come to favour are saphenous vein homografts or heterografts with PTFE. The respective results seem to us equivalent so that either option can be held justified.

Actuarial Analysis↗
PubMed1992

Superior mesenteric arteriovenous fistula after ileal resection.

Postoperative superior mesenteric arteriovenous fistula is very rare. We report the case of a 55-year-old woman in whom the discovery of an abdominal bruit led to the diagnosis of superior mesenteric arteriovenous fistula seven years after ileal resection. The clinical and pathophysiological aspects, as well as the therapeutic modalities, of this rare lesion are reviewed.

Angiography, Digital Subtraction↗
PubMed1991

[Coronary surgery in patients aged 70 years and older. 65 cases].

Out of 428 patients operated upon for coronary disease between December 1984 and November 1989, sixty-five (15.18 percent) were 70 to 80 years' old. All were suffering from a more or less invalidating stage II, III or IV angina. Coronary arteriography showed severe lesions of two or three main vessels (24.6 and 60 percent respectively). Each patient underwent 2.06 bypasses on average. Perioperative mortality was 7.7 percent, and late mortality 1.53 percent. The postoperative myocardial infarction rate was 4.61 percent, and 83 percent of these patients became asymptomatic. There was no deterioration. These satisfactory results are the consequences of numerous technical advances in cardiovascular surgery, anaesthesia and intensive care. As more and more elderly patients undergo coronary surgery, the desire of other elderly patients to be operated upon and their comfort after coronary surgery, the desire of other elderly patients to be operated upon and their comfort after coronary bypass are two additional reasons to opt for surgery. In spite of new vascular recanalization techniques, coronary surgery remains of considerable value. Close cooperation between surgical and medical teams should clarify the respective indications for coronary angioplasty and direct coronary bypass, thereby making these two procedures complementary and no longer competitive.

Aged↗
PubMed1991

Conservative treatment of prosthetic aortic graft infection with irrigation.

An infected prosthetic aortic graft is usually treated by ablation of the graft associated with extraanatomic bypass. In spite of this aggressive attitude, mortality and morbidity remain high, especially due to secondary rupture of the aortic stump. We report the case of a patient who incurred periprosthetic purulent collection four weeks after insertion of an inlay aortobiiliac prosthetic graft for aneurysm, who was treated by debridement, irrigation, and omental transposition. Recovery has been maintained for four years. Conservative treatment of infection can control infection and obviate the need of complex resection and revascularization procedures.

Anti-Bacterial Agents↗
PubMed1991

Femorofemoral crossover bypass for noninfective complications of aortoiliac surgery.

Between 1973 and 1989, 39 femorofemoral crossover bypasses were performed to treat unilateral noninfective complications of aortoiliac surgery. The initial revascularization procedure, performed an average of 79.5 months previously, was an aortobifemoral bypass in 29 cases, an aorto- or iliofemoral bypass in six cases, an inlay graft for abdominal aortic aneurysm and aortoiliac endarterectomy in two cases each. The indications for femorofemoral crossover bypass included prosthetic occlusion in 35 cases, thrombosed false aneurysm in two, and further degradation after endarterectomy (iliac stenosis and occlusion in one case each). There was no operative mortality. One patient with acute ischemia upon admission and another with distal gangrene required below-knee and forefoot amputations, respectively. No amputations were required during the rest of the follow-up period. Three repeat aortobifemoral bypasses were performed because of occurrence of aortic or inflow vessel lesions. Primary and secondary actuarial five year patency rates for femorofemoral crossover bypasses were 59.7% and 78.4%, respectively. Femorofemoral crossover bypass can extend the benefits derived from direct aortoiliac surgery with low mortality and morbidity in the absence of associated aortic pathology (false aneurysm at the aortic implantation site or severe obstructive lesions).

Aged↗
PubMed1991

[Progress in the surgery of abdominal aortic aneurysm].

Between 1960 and 1989, 609 patients were operated on for abdominal aortic aneurysms. They were 38 females and 571 males from 45 to 87 years old (mean 69). The series has been divided into three consecutive periods: From 1960 to 1973, 135 patients (30 ruptures); from 1974 to 1981, 176 patients (55 ruptures) and from 1982 to 1989, 298 patients (49 ruptures). Perioperative mortality for elective surgery was 8.5% during the first period and 3.2% during the last one. For ruptured aneurysms mortality decreased from 66% to 34%. In the same way, the incidence of rupture decreased from 31.2% to 16.4%. Progresses making possible improvements of the results are related to an early detection with ultrasounds and CT scan, a more precise evaluation of associated pathologies, simplification of surgical techniques, evolution of anesthesia and supportive measures (monitoring, autologous transfusion). On the other hand, rupture is still lethal due to delay in diagnosis and surgery, site of the rupture and multiorgans consequences of hemorrhagic shock. It is only by an echographic screening of people at risk (age, cardiovascular diseases) that frequency can be reduced.

Aged↗
PubMed1990

[Role of x-ray computed tomography in the preoperative evaluation of aneurysm of the abdominal aorta].

The authors have studied the files of 50 consecutive patients (1987-89) operated for abdominal aortic aneurysm (AAA) and examined with CT. The criteria for inclusion were surgical features. CT can be made more accurate for the study of AAA: Thus the location of the neck of the aneurysm relative to the renal arteries was defined in 94% of all cases. In addition, CT yields information about the wall of the aneurysm, whether it be thickened (3 inflammatory aneurysms were properly diagnosed) or, mor importantly, weakened (solution of continuity in the wall in the "prior-to-rupture" appearance). Owing to the quality of its performances and to its noninvasive character, the authors regard CT with contrast injection as an essential technique for the preoperative assessment of abdominal aortic aneurysm in most cases. The examination must be carried out strictly, especially for the contiguous sections of the renal arteries and their extension to the crural arch. As it demonstrates weakened areas more easily, a more accurate study of the aneurysmal wall with CT might increase the surgical indications for some smaller aneurysms, the potential evolution of which does not seem to be associated with their diameter only.

Aged↗