Search PubMed⌕ Search

Biomedical subjects

G Leroy

Publications and source records attributed to G Leroy.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Left ventricular kinetics studied by the color kinesis method. Comparison of bidimensional echographic and angiographic data].

The object of this study was to assess the value of CK in the evaluation of left ventricular wall motion. Fifteen coronary patients aged 56 +/- 12 years were included: 8 patients were examined after acute myocardial infarction and 7 after unstable angina with a history of myocardial information. The left ventricle was divided into 7 segments after a modified Heger model, excluding the basal septal and basal lateral segments not seen on angiography. The left ventricular wall motion was assessed in two-dimensional echocardiography (2DE) and colour kinesis (CK) by two observers and compared with the results of left ventriculography, considered the reference method. Over all the 105 segments studied (7 segments for each of the 15 patients), CK was significantly better than 2DE (80% of segments correctly evaluated by CK vs 68% by 2DE, p < 0.05). Colour kinesis significantly improved the study of all segments except the interventricular septum (67% vs 60%, p = NS). The inter-observer variability in 2DE and CK evaluated over 135 segments (9 per patient) by the kappa was improved by colour kinesis (0.57 in 2DE, 0.7 in CK). The authors conclude that CK enables evaluation of left ventricular wall motion with greater precision and less inter-observer variability.

Aged↗
PubMed1997

A single mutation in the heme 4 environment of Desulfovibrio desulfuricans Norway cytochrome c3 (Mr 26,000) greatly affects the molecule reactivity.

The gene encoding Desulfovibrio desulfuricans Norway cytochrome c3 (Mr 26,000), a dimeric octaheme cytochrome belonging to the polyheme cytochrome c3 superfamily, has been cloned and successfully expressed in another sulfate reducing bacteria, D. desulfuricans G201. The gene, named cycD, is monocistronic and encodes a cytochrome precursor of 135 amino acids with an extension at the NH2 terminus of 24 amino acids. This extension acts as a signal sequence which allows export across the cytoplasmic membrane into the periplasmic space. Tyrosine 73, which is in a close contact with the histidine sixth axial ligand to the heme 4 iron atom, has been replaced by a glutamate residue using site-directed mutagenesis. The cytochrome mutant when expressed in D. desulfuricans G201, is correctly folded and matured. A global increase of the oxidoreduction potentials of about 50 mV is measured for the Y73E cytochrome. The mutation also has a strong influence on the interaction of the cytochrome with its redox partner, the hydrogenase. This suggests, like the tetraheme cytochrome c3 (Mr 13, 000), heme 4 is the interactive heme in the cytochrome-hydrogenase complex and that alteration of the heme 4 environment can greatly affect the electron transfer reaction with its redox partner.

Amino Acid Sequence↗
PubMed1997

[Severe type 7 Adenovirus pneumoniae in an immunocompetent adult].

We report a case of severe Adenovirus type 7 pleuropneumonia in an immunocompetent adult. The treatment required a mechanical ventilation with tracheostomy. The sequelae was a restrictive respiratory insufficiency. Adenovirus is a common cause of pneumonia in children, in military recruits or in immunocompromised adults. However, it is an infrequent cause of such a severe complication in a healthy adult.

Adenovirus Infections, Human↗
PubMed1997

Infrared and Raman microspectrometry study of fluor-fluor-hydroxy and hydroxy-apatite powders.

Visible Raman and infrared microspectrometry studies performed on fluorapatite and hydroxyapatite powders have shown similar results. Small modifications of the nu2 and nu4 PO(3-)4 tetrahedra bending modes are observed. A small frequency shift of the nu1 mode and modifications on the nu3 mode region accompanied with a simplification of the hydroxyapatite and fluorapatite respective spectra from seven to four bands were observed. A broad and weak band which could be attributed to the Ca-F bond is detected at 311 cm(-1) on the Raman fluorapatite spectra. The phosphate vibration modes are little disturbed by fluoride substitution. This could indicate that phosphate groups interact strongly between themselves and weakly with substituted atoms (i.e. hydroxyle and fluoride atoms). Whatever crystallographic model is considered, the number of bands observed is always lower than the number of calculated ones, even for hydroxyapatite, whose symmetry is lower than that of fluorapatite.

Journal Article↗
PubMed1997

[Kearns-Sayre syndrome. A rare indication for prophylactic cardiac pacing].

The authors report a case of Kearns-Sayre syndrome, a rare mitochondrial myopathy, diagnosed in a 19 year old man. Distal conduction defects are constant findings and are a dominant factor in the prognosis of this condition. Their early appearance and rapid progression pose the problem of prophylactic cardiac pacing despite the young age. In the case report, pacing was decided at the age of 23 in the absence of symptoms but with bifascicular block (right bundle branch block and left anterior hemiblock), without electrophysiological investigation. During follow-up, left bundle branch block was observed 3 years later and permanent complete atrioventricular block occurred 7 years after pacemaker implantation.

Adult↗
PubMed1997

[Spontaneous reduction of late chronic atrial fibrillation after mitral valvuloplasty. Echocardiographic evidence of the restoration of mechanical atrial activity].

Spontaneous, long lasting reduction of chronic permanent atrial fibrillation, usually complicating rheumatic valvular heart disease, has rarely been described in the literature. Its mechanism is unclear. In practice, the question is to determine whether the electrical activation coincides with restoration of a mechanical atrial contraction. The authors report the case of a woman with mixed rheumatic aortic and mitral valve disease (essentially mitral stenosis), in whom reversion to sinus rhythm was observed after 9 years of atrial fibrillation and which was long lasting (at least 9 months), and, above all, accompanied by atrial contraction documented for the first time to the best of the authors' knowledge, by Doppler echocardiography.

Atrial Fibrillation↗
PubMed1997

[Left ventricular reduction (Batista's technique). A new surgical option in dilated cardiomyopathy].

Cardiac transplantation remains the standard treatment for severe cardiomyopathy resistant to medical therapy. However, new techniques may help to put this off. Two patients with dilated cardiomyopathy were treated surgically since October 1996, one aged 48 and the other 52. They were in NYHA Class IV and one was dependent on inotropic drugs. Both had relative or absolute contra-indications to transplantation. The left ventricular end diastolic dimensions were over 70 mm with mild mitral regurgitation and fractional shortening of less than 12%. Coronary angiography was normal. They were operated in October 1996 and January 1997. The procedure consisted of correction of mitral regurgitation (annuloplasty) and of reduction of left ventricular volume by a triangular resection from the apese to the base of the heart. At histological examination, the resected myocardium measured 11 to 13 cm long and 5 to 7 cm at its base. The two patients were discharged from hospital after 45 and 30 days. There were no clinical signs of cardiac failure. Follow-up investigations showed a marked decrease in ventricular volumes, the end diastolic dimensions changing from 70 to 52 mm in the first, and from 76 to 54 mm in the second patient. The corresponding values of fractional shortening increased from 11 to 20% and from 6 to 17%. Left ventricular volumes decreased from 328 mL (end diastole) and 259 mL (end systole) to 140 mL and 74 mL in the first case, and from 300 mL (end diastole) and 280 mL (end systole) to 122 mL and 83 mL respectively in the second case. The ejection fraction increased from 20 to 40% and from 10 to 32%. These preliminary results show that the theoretical advantages of this surgical technique correspond to a practical reality. Larger series of patients are required to determine the optimal indications.

Cardiac Surgical Procedures↗
PubMed1997

[Myocardial infarction in a pregnant woman during salbutamol therapy].

The authors report the case of a 31 year old woman at 30 weeks' gestation who developed a non-Q wave postero-lateral myocardial infarction during treatment with salbutamol. There were no complications and delivery took place at term normally. Coronary angiography was performed 3 months post-partum and was normal: the Methergin test was negative. Myocardial ischaemia occurring during treatment with a beta-2 mimetic in pregnancy is rare and hardly ever progresses to myocardial infarction. The usual mechanism of ischaemia is an imbalance of myocardial oxygen demand and supply. Myocardial oxygen consumption is naturally increased during pregnancy and excess intracellular calcium secondary to the beta-1 stimulation occurring with the use of beta-2 mimetic drugs further aggravates matters. This hypothesis raises the question of the value of calcium inhibitors in these forms of myocardial ischaemia.

Abortion, Threatened↗
PubMed1996

The cytochrome c3 superfamily: amino acid sequence of a dimeric octahaem cytochrome c3 (M(r) 26,000) isolated from Desulfovibrio gigas.

Cytochrome c3 (M(r) 26000) isolated from Desulfovibrio gigas is a dimeric cytochrome consisting of two identical subunits of 109 amino acids, each of which contains four haem groups. On the basis of its amino acid sequence, this cytochrome clearly belongs to the cytochrome c3 superfamily, and will be classified in class III of the c-type cytochromes as defined by Ambler [(1980) in From Cyclotrons to Cytochromes (Robinson, A. B. and Kaplan, N. O., eds.), pp. 263-279, Academic Press, London]. It contains ten cysteine and nine histidine residues in each subunit, and eight cysteines and eight histidines linked to the four haem groups were found to be invariant on alignment of all known cytochrome c3 sequences. Two intermolecular disulphide bridges have been determined between cysteine residues 5 and 46 of the two monomers. Cytochrome c3 (M(r) 26,000) from D gigas is clearly different from cytochrome c3 (M(r) 13,000) from the same strain, with which it shows only 27% sequence identity. Compared with cytochrome c3 (M(r) 26,000) from D. desulfuricans Norway, the three-dimensional structure of which has been determined, 26.95% of the residues have been conserved. In the enzyme from D. desulfuricans Norway, hydrophobic interactions have been described across the dimer interface. Residues involved in similar interactions seem to be well conserved in the equivalent D. gigas cytochrome. This sequence provides structural data to allow specification of this new subclass of polyhaem cytochromes. Furthermore, D. gigas cytochrome c3 (M(r) 26,000) is the first polyhaem cytochrome shown to contain two disulphide bridges linking two identical subunits, which could induce more rigid folding. The folding and the evolution of this family of polyhaem cytochromes are discussed.

Amino Acid Sequence↗
PubMed1996

Estradiol-dependent uterine leiomyomas in transgenic mice.

Uterine leiomyomas are a major health problem for women of reproductive age. The molecular biology of these tumors is poorly understood partly because of the lack of relevant animal models. We have produced transgenic mice expressing the simian virus 40 T antigen driven by the promoter of the Calbindin-D9K (CaBP9K) gene and either -1,000 or -117 bp of regulatory sequences so as to establish in vivo, uterine smooth muscle tumor models. Six transgenic mouse lines were obtained. Leiomyomas developed in all of them, with an almost complete penetrance of the phenotype. The smooth muscle tumors arose in different parts of the female reproductive tract. Leiomyomas usually developed in the corpus of the uterus, but one mouse line developed leiomyomas in the horn of the uterus, and another in the vagina. The CaBP9K regulatory sequences directing the expression of the Tag gene possess an estradiol responsive element, and accordingly, development of the tumors was strictly under the control of estrogen. Expression of the Tag gene is not only necessary for the initiation of the tumor but also for its development and maintenance. These transgenic mouse models should be useful for studying the pathobiology of uterine leiomyomas and could be instrumental in designing new therapeutic approaches to this disease.

Animals↗
PubMed1996

Radiological confirmation of brain death: digitised cerebral parenchymography. Preliminary report.

Rates of organ procurement from brain dead subjects have fallen substantially in recent years. In France, the legal definition of brain death is based on electroencephalographic criteria in patients with clinical evidence of irreversible coma. However, sedative drugs used in intensive care units usually render the electroencephalogram uninterpretable, and in our medicolegal framework, it is necessary that intracerebral circulatory arrest be demonstrated. We discuss the value of the various available techniques and report our experience with digitised intra-arterial cerebral parenchymography. This simple, fast technique does not alter physiological conditions and provides high-quality images, ensuring prompt diagnosis, which is a prerequisite for optimal organ harvesting.

Brain Death↗
PubMed1995

[Sensitivity in vivo and in vitro of Plasmodium falciparum to chloroquine and amodiaquine in Bangangte (west Cameroon)].

A cross-sectional malaria survey was conducted during the rainy season in Bangangté (West-Cameroon), a town of 90,000 inhabitants located in the high tablelands zone of Cameroon. An in vivo study revealed that 50% of P. falciparum malaria patients were resistant to chloroquine (25 mg/kg over 3 days) and 26.3% to amodiaquine (35 mg/kg over 3 days) at a RII/RIII level. In addition, plasmodial indices indicated that malaria was mesoendemic in this area of Cameroon.

Adolescent↗
PubMed1995

[Syncopal ventricular tachycardia complicating paroxysmal atrial fibrillation in severe myocardial ischemia].

The authors report two cases of spontaneous paroxysmal atrial fibrillation closely followed by syncopal ventricular tachycardia resulting in cardiac arrest requiring defibrillation. Both patients, men aged 62 and 64 years, had a past history of myocardial infarction without arrhythmias; atrial fibrillation occurred during severe myocardial ischaemia; coronary arteriography showed tight stenoses of the left main coronary artery with normal left ventricular function. Ventricular tachycardia (or fibrillation) during spontaneous paroxysmal atrial fibrillation is a rare occurrence. This sequence of events has been described in patients with accessory conduction pathways or in hypertrophic cardiomyopathy. It is an exceptionally rare complication of ischemic heart disease with only a very few previously reported cases. Myocardial ischaemia is probably the cause of the arrhythmia in together with irregularity of the ventricular contractions responsible for long cycle-short cycle sequences which are particularly arrhythmogenic and changes in sympathetic tone.

Atrial Fibrillation↗
PubMed1994

Amino-acid sequence of the cytochrome c3 (M(r) 26,000) from Desulfovibrio desulfuricans Norway and a comparison with those of the other polyhemic cytochromes from Desulfovibrio.

The amino-acid sequence of an octaheme cytochrome c3 isolated from Desulfovibrio desulfuricans Norway is presented. The protein molecule (M(r) 26,000) comprises two identical subunits of 111 amino acids with the characteristics typical of tetrahemic cytochrome c3 class. Comparisons between the amino-acid sequences and physiological properties of cytochrome c3 (M(r) 26,000) and cytochromes c3 (M(r) 13,000) isolated from various species of Desulfovibrio showed the existence of considerable differences. In order to distinguish between the various subclasses in the cytochrome c3 superfamily, the amino-acid sequence of cytochrome c3 (M(r) 26,000) was compared with six known cytochrome c3 (M(r) 13,000) sequences as well as with the sequence of the four c3-like domains of a high molecular weight cytochrome c (Hmc) containing 16 hemes per molecule of 65,500 Da, isolated from Desulfovibrio vulgaris Hildenborough. The evolution and phylogenetic relationships of these various polyhemic cytochromes are discussed.

Amino Acid Sequence↗
PubMed1992

[Should coronary angiography be practiced in patients with recent myocardial infarction?].

As a rule, infarction results from an occlusive thrombosis in a pre-existing atherosclerotic stenosis. Contrary to intravenous thrombolysis, coronary arteriography with immediate removal of obstruction can only be performed in a minority of patients. Similarly, "salvage angioplasty", performed if thrombolysis has failed, does not justify early coronary arteriography, except in certain cases of infarction at very high risk. In 80% of the cases the first days are uneventful, but the mortality in the first year (about 10%) will depend upon the presence or absence of latent residual ischaemia and/or left ventricular dysfunction. A noninvasive evaluation carried out before the patient is discharged and including clinical and echocardiographic data as well as the results of stress tests (sometimes coupled with isotopic studies) may isolate an important group of patients (40%) whose mortality rate at one year is below 3%. Systematic coronary arteriography, therefore, is not justified, especially since it facilitates the "easy" decisions of angioplasty the benefits of which has not been demonstrated in the absence of residual ischaemia during exercise.

Coronary Angiography↗
PubMed1992

Biochemical and spectroscopic characterization of the high molecular weight cytochrome c from Desulfovibrio vulgaris Hildenborough expressed in Desulfovibrio desulfuricans G200.

The gene of high molecular weight, multiheme cytochrome c (Hmc) from the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough has been overexpressed in Desulfovibrio desulfuricans G200. The recombinant protein has been purified. Its molecular weight (65,600), amino acid composition, and NH2-terminal sequence were found to be identical to those of the wild-type protein. The recombinant protein has been spectroscopically characterized (optical spectrum, EPR, circular dichroism) and compared to the wild-type protein. We have found 16 hemes per molecule by iron analysis and the pyridine hemochrome test. Both high- and low-spin features were observed in the EPR spectrum. A detailed spin quantitation analysis indicates 1 or 2 high-spin hemes and 14 or 15 low-spin hemes per molecule. The redox potentials of the hemes determined by voltammetric techniques gave an average of three different values, 0, -100, and -250 mV (versus NHE), for the wild-type and the recombinant cytochrome. The low potential values are similar to the values observed for the bis(histidinyl) coordinated hemes of cytochrome c3. A comparison of the arrangement of heme binding sites and coordinated histidines in the amino acid sequences of cytochrome c3 and Hmc has shown that the latter contains four domains, three of which are complete c3-like domains, while the fourth represents an incomplete c3-like domain which may contain His-Met coordinated hemes. These data are in agreement with the detailed study of the number and types of hemes reported in this paper.

Amino Acid Sequence↗