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G Dreyfus

Publications and source records attributed to G Dreyfus.

At least 55 records · Page 3Linked to original sources
PubMed1996

A model for pheromone discrimination in the insect antennal lobe: investigation of the role of neuronal response pattern complexity.

Based on anatomical and physiological data pertaining to several moth species and the cockroach, we propose a neural model for pheromone discrimination in the insect antennal lobe. The model exploits the variety of neuronal response patterns observed in the macroglomerulus, and predicts how these complex patterns of excitation and inhibition can participate in the discrimination of the species-specific pheromone blend. The model also allows us to investigate the relationship between the distribution of observed response patterns and the neural organization from which these patterns emerge.

Action Potentials↗
PubMed1996

[Surgery FOR annulo-dystrophic disease of the ascending aorta. Apropos of 203 cases].

From April 73 to June 94, 203 patients (167 men, 36 women) aged from 10 to 74 years (mean 44.8 +/- 15) underwent ascending aortic replacement with a composite graft for: dystrophic aneurysm (AN) (130 cases, 64.5%), chronic dissection (CD) (35 cases, 17.2%), type A acute dissection (AD) (38 cases, 19%). Forty-six patients (22.6%) suffered from Marfan syndrome (24 AN, 13 AD, 9 CD). Thirty patients (14.7%) had undergone a previous cardiac or aortic operation. The ascending aortic replacement was extended to the transverse arch in 28 patients (14%). A mechanical valve was used in 193 cases (95%). The technique of coronary reattachment has varied with time and according to the aortic lesions. The classic "Bentall" technique was used in 87 patients (43%), the "button" technique in 74 (36%), the "Cabrol" technique in 26 (13%) and a "mixed" technique in 16 cases (8%). The hospital mortality rate was 7.3% (15/203) (AN: 2.3%, CD: 11.4%, AD: 21%). The only predictors of hospital death were emergency AD (p < 0.03) and arch replacement (p < 0.02). Mean follow-up was 46 +/- 10 months (2-246). The overall long-term survival rate was (Kaplan Meier) 89 +/- 6% at 1 year, 77.9% at 5 years, 67.7 +/- 12% at 10 years and 61.3% +/- 15% at 12 years. The 10 years survival rate is significantly higher in patients with AN (77.8 +/- 11%) than in those with AD (61.6 +/- 17%) (Log.rank: p < 0.01). The late survival rate is also significantly higher after the "button" or Bentall reimplantation that after the "Cabrol" or "mixed" methods (90 +/- 5% in the "button" group and 88.7 +/- 6%, 83.8 +/- 9% and 76.6 +/- 12% in the "Bentall" group vs 80 +/- 18%, 63 +/- 21% and 58 +/- 35% in the "Cabrol" group at 1, 5 and 8 years, respectively). In conclusion, ascending aortic replacement with a composite graft is a safe procedure especially when performed electively in patients with dystrophic aneurysm or Marfan syndrome. The technique of coronary reimplantation has a significant on the long-term results.

Actuarial Analysis↗
PubMed1996

A column centrifugation method for the reconstitution in liposomes of the mitochondrial F0F1 ATP synthase/ATPase.

A method for reconstitution of membrane proteins into unilamellar liposomes is described. The model enzyme was the F0F1 ATP synthase from mitochondria when in complex or free from its inhibitor protein. The enzymes were first solubilized with either of two detergents, i.e., n-dodecyl-beta-D maltoside or lauryldimethylamine oxide. After solubilization, the enzymes were passed through a column of Sepharose-AH using an ADP/sodium cholate selective elution buffer. The enzymes recovered from the column were subsequently passed through a centrifuge column of Sephadex G-50 fine. The eluate contained liposomes in which the F0F1 complex (with and without inhibitor protein) had been reconstituted. The reconstituted enzymes were capable of hydrolyzing ATP with formation of electrochemical H+ gradients. They also catalyzed the ATP-Pi exchange reactions. Thus the F0F1 complex which is formed by 18 subunits can be rapidly reconstituted into liposomes in a fully functional state. Moreover the data show that the interactions between the enzyme and its inhibitor protein are not perturbed in the reconstitution procedure.

Animals↗
PubMed1996

[Emergency cardiac transplantation].

Emergency cardiac transplantation is a controversial subject in the present context of a lack of donor organs. There are few reports in the literature, which the authors review to suggest a practical approach which is clearly not consensual. The results in the literature report an extramortality of 10 to 30% if the indication of transplantation is that of an emergency. The poor results of emergency transplantation in the present day context of lack of donor organs have led the authors to abandon this indication. They only transplant patients in a stable condition without failure of organs other than the heart.

Actuarial Analysis↗
PubMed1995

[Anti-thyroid autoantibodies in hepatitis C. Thyroid function after interferon therapy in 4 patients].

Four female patients had chronic hepatitis C associated with antithyroid autoantibodies. Hepatitis C virus infection was evidenced by liver biopsy and a positive-four-antigen recombinant immunoblot assay. All four patients were euthyroid before interferon therapy. Recombinant interferon alpha was given at a dose of 3 millions units three times a week for 6 months. At the end of the treatment, serum aminotransferase levels were within the normal range. Two patients progressed to hypothyroidism and 2 patients remained euthyroid. One year after the end of the treatment, only one patient had hypothyroidism and another had normal serum aminotransferase levels. These case-reports suggest that interferon administration may induce thyroid dysfunction in patients with antithyroid autoantibodies at the beginning of treatment. Thyroid dysfunction may be reversed when cytokine is withdrawn.

Adult↗
PubMed1995

Anti-GOR and anti-thyroid autoantibodies in patients with chronic hepatitis C.

Anti-thyroid autoantibodies have been described in anti-hepatitis C virus (HCV)-positive patients. It has been suggested that the anti-GOR response is closely related to HCV infection and may reflect an HCV-associated autoimmune phenomenon. This study was designed to evaluate the humoral anti-GOR response in anti-HCV-positive patients with anti-thyroid autoantibodies (group 1, 22 patients) and to compare it with the response in anti-HCV-positive patients without anti-thyroid autoantibodies (group 2, 44 patients) and in anti-HCV-negative patients with autoimmune thyroiditis (group 3, 28 patients). The prevalences of anti-GOR in groups 1, 2, and 3 were, respectively, 72.7, 61.3, and 3.5%. Anti-GOR levels were higher in group 1 than in group 2 or group 3 (P = 0.0001). Moreover, comparison of the Anti-GOR levels of groups 1 and 2 also revealed a statistically significant difference (P = 0.008). Detection of more elevated anti-GOR levels in group 1 patients suggests that anti-thyroid autoantibodies in anti-HCV-positive patients may be related to HCV.

Aged↗
PubMed1995

The native F0F1-inhibitor protein complex from beef heart mitochondria and its reconstitution in liposomes.

A functional F0F1 ATP synthase that contains the endogenous inhibitor protein (F0F1I) was isolated by the use of two combined techniques [Adolfsen, R., McClung, J.A., and Moudrianakis, E. N. (1975). Biochemistry 14, 1727-1735; Dreyfus, G., Celis, H., and Ramirez, J. (1984). Anal. Biochem. 142, 215-220]. The preparation is composed of 18 subunits as judged by SDS-PAGE. A steady-state kinetic analysis of the latent ATP synthase complex at various concentrations of ATP showed a Vmax of 1.28 mumol min-1 mg-1, whereas the Vmax of the complex without the inhibitor was 8.3 mumol min-1 mg-1. In contrast, the Km for Mg-ATP of F0F1I was 148 microM, comparable to the Km value of 142 microM of the F0F1 complex devoid of IF1. The hydrolytic activity of the F0F1I increased severalfold by incubation at 60 degrees C at pH 6.8, reaching a maximal ATPase activity of 9.5 mumol min-1 mg-1; at pH 9.0 a rapid increase in the specific activity of hydrolysis was followed by a sharp drop in activity. The latent ATP synthase was reconstituted into liposomes by means of a column filtration method. The proteoliposomes showed ATP-Pi exchange activity which responded to phosphate concentration and was sensitive to energy transfer inhibitors like oligomycin and the uncoupler p-trifluoromethoxyphenylhydrazone.

Adenosine Triphosphate↗
PubMed1995

[Long-term results of cardiac transplantation].

Between 1982 and 1992, 73 patients who had undergone cardiac transplantation and survived the hospital period, were followed up. The actuarial survival was 86%, 65% and 40% at 1, 5 and 7 years. The main causes of the 14 secondary deaths were infection (4), acute rejection (3) and cancer (3). Survival was complicated by acute rejection (1.07 episodes/patient), infection (0.7 episode/patient), cancer, hypertension and renal failure, graft dysfunction and other more secondary side effects. After analysing all the complications, the authors evaluated the quality of long-term survival after cardiac transplantation which allowed one patient out of two to return to normal living but with the threat of secondary graft dysfunction.

Actuarial Analysis↗
PubMed1995

[Treatment of ifosfamide induced encephalopathy with methylene-blue].

The authors report a case of encephalopathy after treatment with ifosfamide treated by a methylene blue infusion. This side-effect is rare but influenced by high doses and short infusions of this drug. Recently, a treatment of ifosfamide encephalopathy with methylene blue has been reported. This case report confirms the interest of such a treatment.

Aged↗
PubMed1994

[Severe cardiomyopathy revealing amylopectinosis. Two cases in adolescents from the same family].

Type IV glycogen storage disease, also termed Andersen's disease or amylopectinosis, is a rare autosomic recessive hereditary disease usually caused by a deficit in glycogen branching enzyme. We report our observation of two siblings with type IV glycogen storage disease who had normal branching enzyme activity. The initial symptom was severe heart failure. A 14-year-old boy, born to consanguinous parents, was seen for severe global heart failure. Growth retardation had been diagnosed since the age of 6 and abnormal fatigability since the age of 12. Muscle and endomyocardium biopsies revealed abnormal glycogen storage with normal branching enzyme activity. The patient's condition improved after symptomatic treatment, but death occurred due to infectious complications after orthoptic heart transplantation. One year later, the proband's 12-year-old sister, with an uneventful personal medical history, was hospitalized for severe left ventricular failure. Muscle and liver biopsies demonstrated the same anomalies, again without branching enzyme deficiency in the liver. Heart failure was controlled with symptomatic care and the patient's current condition remains satisfactory. This observation demonstrates the clinical expression of familial type IV glycogen storage disease in patients with normal branching enzyme activity. Age at onset is quite variable, reported from 5 to 70 years, as is the clinical course before diagnosis.

Adolescent↗
PubMed1994

Late reoperations in patients with aortic dissection.

Aortic dissection is an evolving process that may require one or several reoperations after the initial emergency repair. From January 1977 to September 1993, 148 patients underwent emergency surgery for type A acute aortic dissection. The replacement of the ascending aorta was extended to include the transverse arch in 43 patients (29%). One hundred fifteen patients (78%) survived surgery. During the same period, 37 patients required reoperation once (28), twice (7), or three times (2), for a total of 48 reoperations. Twenty-one patients had undergone initial repair in our institution; 16 patients had been operated on elsewhere. Reoperation was indicated for: aortic valve disease (4); a new dissecting process (7); threatening aneurysmal evolution of a persisting dissection (34); or false aneurysm (3). The re-do procedure involved: the aortic root and/or ascending aorta in 12 cases (group I); the ascending aorta and the transverse arch in 6 cases (group II); the transverse arch alone in 8 cases (group III); the transverse arch and descending aorta, or the descending aorta alone in 11 cases (group IV); and the thoracoabdominal aorta in 11 cases (group V). Risk factors for reoperation were analyzed in the 115 survivors initially operated on at our institution. Seven of 20 Marfan patients (35%) versus 12 of 95 non-Marfan patients (12.6%) required reoperation (p < 0.02). None of the 31 patients surviving arch replacement at initial repair required a reoperation, versus 21 of 84 (25%) patients surviving replacement limited to the ascending aorta (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Aortic dissection. Prevalence, cause, and results of late reoperations.

From January 1977 to September 1992, 143 patients underwent an emergency operation for type A acute aortic dissection. Because of the location of the intimal tear, the replacement of the ascending aorta was extended to the transverse arch in 42 patients (29.3%). One hundred ten patients (78%) survived the operation. During the same period, 32 patients had to be reoperated on once (n = 24) twice (n = 6), or three times (n = 2) for a total of 42 reoperations. Nineteen patients had had the initial repair in our institution, and 13 had been operated on elsewhere. Reoperation was indicated for aortic valve disease (n = 4), recurring dissection (n = 7) threatening aneurysmal evolution of a persisting dissection (n = 28), or false aneurysm (n = 3). The redo procedure involved the aortic root and/or ascending aorta in 15 cases (group I), the transverse arch alone in 7 cases (group II), the transverse arch and the descending aorta or the descending aorta alone in 10 cases (group III), or the thoracoabdominal aorta in 10 cases (group IV). The risk factors for reoperation have been analyzed in the 110 survivors initially operated on in our institution. Seven of 18 patients with Marfan's syndrome (38.8%) versus 12 of 92 without Marfan's syndrome (13%) were reoperated on (p = 0.023). None of the 30 patients surviving arch replacement at initial repair required a reoperation, versus 19 of 80 (23.7%) patients surviving a replacement limited to the ascending aorta (p = 0.013). The overall mortality rate of reoperation was 21.8% (7/32) with a risk of 16.6% (7/42) at each procedure (group I, 13.3%; group II, 0%; group III, 20%; group IV, 30%). Hospital mortality was influenced by emergency operation (5/10) (p < 0.005) and thoracoabdominal replacement (3/10) (p < 0.035). The late survivals after reoperation are 65.1% +/- 17.6% at 1 year and 55% +/- 19.63% at 5 years (Kaplan-Meier, confidence interval 95%). The late survivals, after the initial repair, of the patients undergoing reoperation are 89.6% +/- 11.0%, 79.3% +/- 14.7%, 53.9% +/- 18.1%, and 35.9% +/- 21.8% at 1, 5, 10, and 12 years, respectively. In conclusion, aortic dissection is an evolving process that may require one or several reoperations after the initial repair. At initial emergency operation, the resection of the entry site, when located on or extending to the transverse arch, has reduced the risk of reoperation, in our experience. Elective reoperation must be considered before the occurrence of complications, especially in patients with Marfan's syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1993

Coronary surgery can be an alternative to heart transplantation in selected patients with end-stage ischemic heart disease.

Patients with ischemic heart disease (IHD) low ejection fraction (EF), and congestive heart failure (CHF), are usually referred for orthotopic heart transplantation (OHT). This study reports our experience with coronary artery bypass grafting (CABG) in patients initially referred for OHT, and suggests guidelines to facilitate the choice of procedure (OHT or CABG). Between January 1990 and December 1991, 32 patients with IHD, proposed for OHT, underwent CABG 31/32 patients were male, the mean age was 58 +/- 12 years (40 to 70). Congestive heart failure was present in all patients and was the main symptom. The mean EF was 23 (14 to 31%), mean cardiac index (CI) 2.4 l/min per m2 (1.6 to 3.1 l/min per m2), mean pulmonary artery mean pressure (MPAP) 26 (20 to 37 mmHg) and mean pulmonary wedge pressure 16 (12 to 22 mmHg). Every patients underwent a myocardial viability study by thallium scintigraphy (n = 32) and/or by positron emission tomography (n = 10). The perioperative mortality was 9.3% (3/32). All long-term survivors (n = 27) are in NYHA Class II with a complete follow-up (mean 18 +/- 6 months). Ejection fraction control either by angiography (n = 15) or by single photon emission computed tomography (n = 12) showed an increase of up to 38% (22%-46%). Three determinant factors influenced the choice of CABG. 1) CI > 21/min per m2, 2) MPAP < 35 mmHg. 3) Detection of myocardial viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Genetic and biochemical analysis of Salmonella typhimurium FliI, a flagellar protein related to the catalytic subunit of the F0F1 ATPase and to virulence proteins of mammalian and plant pathogens.

FliI is a Salmonella typhimurium protein that is needed for flagellar assembly and may be involved in a specialized protein export pathway that proceeds without signal peptide cleavage. FliI shows extensive sequence similarity to the catalytic beta subunit of the F0F1 ATPase (A. P. Volger, M. Homma, V. M. Irikura, and R. M. Macnab, J. Bacteriol. 173:3564-3572, 1991). It is even more similar to the Spa47 protein of Shigella flexneri (M. M. Venkatesan, J. M. Buysse, and E. V. Oaks, J. Bacteriol. 174:1990-2001, 1992) and the HrpB6 protein of Xanthomonas campestris (S. Fenselau, I. Balbo, and U. Bonas, Mol. Plant-Microbe Interact. 5:390-396, 1992), which are believed to play a role in the export of virulence proteins. Site-directed mutagenesis of residues in FliI that correspond to catalytically important residues in the F1 beta subunit resulted in loss of flagellation, supporting the hypothesis that FliI is an ATPase. FliI was overproduced and purified almost to homogeneity. It demonstrated ATP binding but not hydrolysis. An antibody raised against FliI permitted detection of the protein in wild-type cells and an estimate of about 1,500 subunits per cell. An antibody directed against the F1 beta subunit of Escherichia coli cross-reacted with FliI, confirming that the proteins are structurally related. The relationship between three proteins involved in flagellar assembly (FliI, FlhA, and FliP) and homologs in a variety of virulence systems is discussed.

Adenosine Triphosphate↗
PubMed1993

High prevalence of thyroid autoantibodies in a prospective series of patients with chronic hepatitis C before interferon therapy.

After describing two cases of Hashimoto's thyroiditis associated with chronic hepatitis C, we set up a prospective study to assess the prevalence of thyroid autoantibodies (thyroglobulin and thyroid microsomal autoantibodies) in 72 chronic hepatitis C patients (43 men and 29 women; mean age = 51 +/- 2.1 yr) before interferon therapy admitted between January and December 1991 to our liver unit. Thyroid autoantibodies were systematically assayed in 60 chronic HBsAg-positive patients (34 men and 26 women; mean age = 50 +/- 2.2 yr), who served as controls. Antibody to hepatitis C virus was detected with a second-generation enzyme immunoassay and then confirmed with a recombinant immunoblot assay and a supplemental enzyme immunoassay using two beads. In chronic hepatitis C patients, no men had thyroid autoantibodies. Nine of 29 women (31%) had thyroid autoantibodies. Among them, six (20.7%) had high titers of thyroid autoantibodies, and two had hypothyroidism. In all nine of these women, hepatitis C virus viremia was detected on nested polymerase chain reaction (with primers located in the 5' untranslated region). One year later, titers of thyroid autoantibodies had increased in one patient. Three other patients progressed to hypothyroidism. We judged four of 29 patients (13.8%) to have Hashimoto's thyroiditis on the basis of their high titers of thyroid autoantibodies and biological features of hypothyroidism. In the control group, only one man had thyroid microsome autoantibodies, at a very low titer (1:100). The association between chronic hepatitis C and presence of thyroid autoantibodies is clearly confirmed (p = 0.021) by this study.

Autoantibodies↗
PubMed1993

[Surgery in acute bacterial endocarditis. Restraints--possibilities].

The limitations and possibilities of surgery in acute infective endocarditis depend on the indication, haemodynamic or bacteriological, the site of infection, aortic or mitral, and whether affecting a native or prosthetic valve. The common possibility of conserving the mitral valve in acute endocarditis is an additional therapeutic option. Similarly, the use of aortic homografts has improved the results in aortic endocarditis. Surgical principles have therefore evolved with conservative mitral valve surgery and "biological" aortic valve replacement. Techniques in prosthetic valve endocarditis have not surgery and earlier extra-anatomical procedures to avoid multiple recurrence with use of homografts or Danielson's technique for the aortic orifice. There have been fewer innovations for recurrent endocarditis on mitral valve prostheses. Irrespective of the site or type of endocarditis, the precocity of surgical treatment is an essential prognostic factor.

Acute Disease↗
PubMed1993

Aortic dissection: anatomic types and surgical approaches.

Our classification system of acute dissection of the aorta is based on the site of the main intimal tear: Type A: on the ascending aorta; type B: on the transverse aortic arch; type C: on the descending aorta. The extension of the dissecting process is classified as "antegrade" or "retrograde". Acute dissection involving the ascending aorta is an absolute surgical urgency. Any delay in referring the patient to a proper surgical institution or to the operating room increases the risk of death. Fifty per cent of patients, indeed, either untreated or medically supported, die within 48 hours after the onset of symptoms. Surgical therapy is mainly aimed at preventing the patient from dying from intrapericardial rupture of the aorta or from acute massive aortic regurgitation. In type A, it is necessary to replace the ascending aorta with a bloodtight Dacron prosthesis after resecting the entry site, if possible. Downstream, joining the two dissected cylinders by two running sutures and the aid of GRF glue, seals the false lumen. Upstream, the reconstruction of the aortic root and the resuspension of the aortic valve, also by means of running sutures and GRF glue, suppress the aortic valve insufficiency in 90% patients. However, in case of pre-existing annulo-aortic ectasia, the ascending aorta must be replaced by a composite tube according to the Bentail technique. The use of GRF glue since the beginning of 1977, has dramatically improved the immediate and long-term results, accounting for a hospital mortality rate of 10%, in patients less than 65 years old. In type B, resecting the entry site requires that the transverse arch be partially or totally replaced. It is, therefore, mandatory to protect the Central Nervous System. In our experience this is best achieved by perfusing the carotid arteries with cold blood (6 degrees C) during circulatory arrest at moderate core hypothermia (28 degrees C). With this technique of "Cerebroplegia", the hospital mortality rate has been lowered to 28%, higher, though, than in patients undergoing isolated replacement of the ascending aorta. In type C, only the dissections demonstrating symptoms of major complications (rupture or deleterious ischemia) require urgent surgical treatment. In the remaining cases, medical treatment, based on permanent and accurate control of the patient's blood pressure, lead to a good long-term survival rate. Close survey at regular intervals, by means of CT scan or MNR is mandatory to detect any aneurysmal evolution, which may require surgery.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗