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Biomedical subjects

M Marchand

Publications and source records attributed to M Marchand.

At least 73 records · Page 4Linked to original sources
PubMed1991

Vibrio navarrensis sp. nov., a species from sewage.

A group of 11 strains, mostly isolated from sewage water in the Province of Navarra, Spain, were found to constitute a DNA relatedness group which is 2 to 39% related to 23 species of the genus Vibrio and 2 to 3% related to two Aeromonas species. Phenotypically, these strains have all of the properties that define the genus Vibrio. However, they differ from the previously described species by three or more properties. The strains are negative for arginine, ornithine, and lysine decarboxylase activities and the Voges-Proskauer test and are unable to utilize putrescine, gluconate, glucuronate, and histidine. They utilize and produce acid from sucrose and grow at 40 degrees C. All strains grow in the presence of 0.5% (wt/vol) NaCl, and seven strains grow weakly in peptone water lacking NaCl. The group of strains which we studied can also be differentiated from other Vibrio species by fatty acid content. The G+C ratio of the DNA is 45 to 47 mol%. The name Vibrio navarrensis sp. nov. is proposed for these strains; strain 1397-6 (= CIP 103381) is the type strain.

Base Composition↗
PubMed1990

Characterization of 22 Vibrio species by gas chromatography analysis of their cellular fatty acids.

The cellular fatty acid compositions of 51 Vibrio strains belonging to 22 species as well as five Aeromonas strains were determined by using capillary gas-liquid chromatography (GLC). The major fatty acids were most often hexadecenoic, hexadecanoic and octadecenoic acids. Heptadecenoic acid was present in significant amounts in V. alginolyticus, V. natriegens, V. parahaemolyticus and "Vibrio navarrensis". Twenty fatty acids including branched and hydroxy acids were detected in the genus Vibrio. Quantitative results were treated by principal component analysis to display groups of strains. The first three components (accounting for 69% of the variance) showed the type strains of V. fischeri, V. ordalii, V. damsela, V. mediterranei, V. tubiashii, V. campbellii, V. pelagius, V. gazogenes, and V. nereis to be unclustered. V. alginolyticus (4 strains) and V. parahaemolyticus (4 strains) showed some overlap and the type strain of V. natriegens was in their neighborhood. V. harveyi (4 strains) formed a cluster and V. vulnificus was in its vicinity. V. cholerae (5 strains) overlapped with V. diazotrophicus (3 strains) and was close to the type strain of V. mimicus and V. anguillarum. V. metschnikovii (3 strains) clustered with the type strain of V. cincinnatiensis. A decision tree was devised for the identification of Vibrio species based on qualitative characteristics of fatty acid patterns. However, the following three groups, V. alginolyticus-V. parahaemolyticus-V. natriegens, V. metschnikovii-V. cincinnatiensis and V. cholerae-V. mimicus could not be split into such a decision tree.

Aeromonas↗
PubMed1990

[Determination of C3a and C5a in hemapheresis procedures].

Study of the interface between blood and artificial surfaces reveals numerous undesirable reactions. For example, the formation of biologically active peptides, C3a and C5a (anaphylatoxins), is a result of complement activation via the alternative pathway. It cannot be denied that the reinjection of large quantities of these molecules could be at the origin of serious side effects. We report herein the anaphylatoxin levels found with 9 hemapheresis procedures (4 plasma filtration membranes, 3 systems for platelet collection, 2 plasma treatment techniques (dextran sulfate cellulose column and cascade filtration)). All the filtration procedures generated very high levels of anaphylatoxins, especially C3a. In contrast, the centrifugation systems produced lower levels. However, considerable amounts of C3a were found with the Cobe Spectra and V50 Haemonetics blood cell separators. The anaphylatoxins generated by the primary filter were partially retained by the dextran sulfate column. These high toxin levels enable an assessment of the degree of hemo-incompatibility of these systems. However, it remains difficult to evaluate whether these anaphylatoxins are dangerous or not.

Blood Component Removal↗
PubMed1989

Glucosephosphate isomerase from Trypanosoma brucei. Cloning and characterization of the gene and analysis of the enzyme.

In Trypanosoma brucei the enzyme glucose-6-phosphate isomerase, like most other enzymes of the glycolytic pathway, resides in a microbody-like organelle, the glycosome. Here we report a detailed study of this enzyme, involving a determination of its kinetic properties and the cloning and sequence analysis of its gene. The gene codes for a polypeptide of 606 amino acids, with a calculated Mr of 67280. The protein predicted from the gene sequence has 54-58% positional identity with its yeast and mammalian counterparts. Compared to those other glucose-6-phosphate isomerases the trypanosomal enzyme contains an additional 38-49 amino acids in its N-terminal domain, as well as a number of small insertions and deletions. The additional amino acids are responsible for the 5-kDa-larger subunit mass of the T. brucei enzyme, as measured by gel electrophoresis. The glucose-6-phosphate isomerase of the trypanosome has no excess of positive residues and, consequently, no high isoelectric point, in contrast to the other glycolytic enzymes that are present in the glycosome. However, similar to other glycosomal proteins analyzed so far, specific clusters of positive residues can be recognized in the primary structure. Comparison of the kinetic properties of the T. brucei glucose-6-phosphate isomerase with those of the yeast and rabbit muscle enzymes did not reveal major differences. The three enzymes have very similar pH profiles. The affinity for the substrate fructose 6-phosphate (Km = 0.122 mM) and the inhibition constant for the competitive inhibitor gluconate 6-phosphate (Ki = 0.14 mM) are in the same range as those of the similar enzymes. The Km shows the same strong dependence on salt as the rabbit muscle enzyme, although somewhat less than the yeast glucose-6-phosphate isomerase. The trypanocidal drug suramin inhibits the T. brucei and yeast enzymes to the same extent (Ki = 0.29 and 0.36 mM, respectively), but it had no effect on the rabbit muscle enzyme. Agaricic acid, a potent inhibitor of various glycosomal enzymes of T. brucei, has also a strong, irreversible effect on glucose-6-phosphate isomerase, while leaving the yeast and mammalian enzymes relatively unaffected.

Amino Acid Sequence↗
PubMed1989

[Hancock pericardial prosthesis. Intrinsic dysfunctions].

The frequency of primary dysfunction of 432 Hancock pericardial bioprosthesis was evaluated during a mean follow-up period of 53.1 months per patient. This frequency was 3.20% valve-year in mitral valve prosthesis and 0.92% valve-year in aortic valve prosthesis. Only one case of calcification was noted. Dysfunction was usually due to tearing of one or several pericardial cusps (25 cases), occasionally to tissue retraction (4 cases). Pathological examination of the explanted valves showed fibrin formation followed by organization into fibrous tissue in the host, retracting or fragilizing the pericardial valvular tissue. A preliminary study of the same group had led to discontinuation of Hancock prosthesis. The long follow-up period makes it possible to compare the results obtained with those of pericardial prosthesis of the same generation, to stress the need for echocardiographic monitoring of the implanted valves and to hope that new techniques of pericardial valve fitting will improve the mechanical reliability of prosthesis which, from the point of view of thrombogenesis and haemodynamics, have unquestionable advantages.

Adolescent↗
PubMed1989

[Angiography of right ventricular volume after surgical repair of tetralogy of Fallot].

Right ventricular volume and ejection fraction were measured in children who had undergone surgical repair for tetralogy of Fallot with excellent results. Fourteen children who had been operated upon at the age of 3 +/- 2.6 years had cardiac catheterization and cineangiography of the right ventricle at the age of 4.6 +/- 2.7 years. Right ventricular volumes were determined from single-plane cineangiography in right anterior oblique projection (Ferlinz method). Eleven children with a normal right ventricle served as controls. Dual projection cineangiography of the pulmonary artery enabled the pulmonary insufficiency to be divided into 4 grades. Echocardiography with colour-coded doppler velocimetry was also performed, showing the absence of residual shunt and of tricuspid, mitral and aortic valve abnormalities. The extension of pulmonary regurgitation flow to the right ventricle was analysed and divided into 4 grades. Pulmonary insufficiency was present in all patients; it was graded 1 or 2 by the two methods in 8 cases (group A) and 3 or 4 by one or the other of the two methods in 6 cases (group B). In 7 patients of group A the operation had included the insertion of a small patch to widen the pulmonary channels (infundibulum alone in 3 cases, transvalvular in 4 cases); in 5 patients of group B a large infundibulo-pulmonary transvalvular patch had been installed. The right ventricular systolic pressure was always below 50 mmHg (mean: 40.9 +/- 6.7 mmHg) and the systolic gradient between right ventricle and pulmonary artery never exceeded 30 mmHg (mean: 14.9 +/- 6.2 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1989

[Total abnormal pulmonary venous return surgically treated in an adult].

The authors report a case of total anomalous pulmonary venous return (TAPVR) draining into the innominate (brachiocephalic) vein, discovered in a 40-year old male patient and successfully treated by surgery. This type of cardiopathy is usually suspected in the neonatal period, being badly tolerated, and such a prolonged survival is quite exceptional. Survival is conditioned by the site of the TAPVR, by the size of the atrial septal defect and also by the presence or absence of an obstacle to the pulmonary venous return and of pulmonary arterial hypertension. In the absence of pulmonary vascular disease, surgical correction is mandatory and results in regression of the symptoms and of the pulmonary arterial hypertension.

Adult↗
PubMed1989

[Aortobronchial fistula developing in a pseudoaneurysm of the horizontal aorta].

Amongst the rare causes of haemoptysis rupture of the great vessels is always a possibility. An aorto-bronchial fistula is a rare complication of thoracic aneurysms of the aorta. A fistula starting from a false aneurysm is exceptionally rare. Our observation concerns a patient of 61 with previous vascular problems who was discovered to have a mediastinal tumour following dysphonia and haemoptysis. Aortography and surgical intervention revealed that this was a false aneurysm of the horizontal part of the aorta which had developed a fistula in the bronchus.

Aorta, Thoracic↗
PubMed1988

Characterization of the genes for fructose-bisphosphate aldolase in Trypanosoma brucei.

In Trypanosoma brucei stock 427 the glycolytic enzyme fructose-bisphosphate aldolase is encoded by two tandemly linked genes of identical sequence. Such a tandem arrangement of aldolase genes is also present in other T. brucei stocks of unrelated origin. In stock 427 one of the allelic genes is a pseudogene, as a result of a one-nucleotide deletion. The genes code for a polypeptide of 371 amino acids, with a calculated molecular weight of 40,940. The protein that is predicted from the gene sequence has 45-48% positional identity with known aldolase sequences of other organisms. The trypanosomal protein is, however, unique in having a 10 amino-acid insertion near its N-terminus and high number of basic residues, a feature it shares with other glycolytic enzymes of T. brucei. These glycolytic enzymes have in common that they are located in microbody-like organelles, the glycosomes. We have previously proposed that the positively charged residues may be involved in the import of the proteins into the organelles.

Amino Acid Sequence↗
PubMed1988

[Pre- and postoperative study of arrhythmia in atrial septal defects (ostium secundum and sinus venosus)].

An electrophysiological study was carried out pre- and postoperatively in 25 patients (children and adults) presenting with an atrial septal defect of the ostium secundum type (OSASD). The purposes of the study were to find out whether early electrophysiological abnormalities were present in children, to compare the results obtained in children and in adults and to evaluate the impact of surgery by comparing preoperative and late postoperative electrophysiological data. Patients were divided into two groups. Group I was composed of 11 children (mean age 8.18 +/- 1.03 years) with a mean pulmonary/systemic blood flow ratio of 2.33 +/- 0.24. Group II comprised 14 adults (mean age 36.79 +/- 4.89 years) with a mean pulmonary/systemic blood flow ratio of 3.42 +/- 0.24. Preoperatively, in group I 55 p. 100 of the patients (6/11) had sinus node dysfunction, 18 p. 100 (2/11) had disturbances of atrioventricular conduction, and none had atrial dysrhythmia. Preoperatively, in group II 43 p. 100 of the patients (6/14) had sinus node dysfunction, 36 p. 100 (5/14) had disturbances of atrioventricular conduction, and 36 p. 100 (5/14) had sustained atrial dysrhythmia (flutter or paroxysmal atrial fibrillation). The frequency of sustained atrial dysrhythmia correlated positively with the patient's age and with the presence of sinus node dysfunction. Following surgical closure of the atrial septal defect, the electrophysiological parameters were not significantly modified in both groups. This study confirmed the presence of early electrophysiological abnormalities of sinus node function and atrioventricular conduction in children with OSASD. The most significant finding in adults was the occurrence of atrial dysrhythmias in the oldest patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Large patent ductus arteriosus and interventricular communication associated with congenital absence of the pulmonary valve].

A case of pulmonary valve agenesis with ventricular septal defect and large patent ductus arteriosus is reported in a neonate. Heart failure occurred at 10 days of life; clinical examination showed continuous murmur. Echocardiography and angiocardiography visualized a major dilatation of the pulmonary artery. At cardiac catheterization there was an important left to right shunt through a large ductus, and pulmonary hypertension. There was also marked pulmonic regurgitation. Because of respiratory distress, ligation of ductus arteriosus was performed at 5 weeks of life. Five years later the patient is still in good condition. Patent ductus arterious is rarely associated with pulmonary valvular agenesis and ventricular septal defect. Our case is not explained by the fetal circulation theory described in this heart malformation.

Abnormalities, Multiple↗
PubMed1988

[Control of the patency of coronary-internal mammary artery bypasses by non-selective angiography].

98 successive coronary bypasses using the internal mammary artery were controlled systematically, at an early stage, about the 17th postoperative day, by non selective brachial angiography using a retrograde injection. This control method, simple, quick, reliable and non-aggressive, enables to visualize the internal mammary artery and the bypassed coronary vessel, over its entire length. There were no failure in the control, nor any local or general complication during this examination. The overall patency of such bypasses, evaluated with this method, is 98 p. cent in our series, with however, 12 p. cent of angiographic aspects of a poorly functional bypass. These aspects are related to a slow flow in the by-pass (spindly internal mammary artery, anastomotic stenosis or thin distal bed of the bypassed coronary artery), or to a competitive flow (non significant coronary stenosis). The perfusion of the bypassed coronary, which is not so well studied in the literature, is important to analyze and difficult to evaluate with our technique because of the static views that are used. A similar non-selective angiographic method using a dynamic recording (radio-cinema with dual incidence) is currently being evaluated.

Adult↗