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Biomedical subjects

B Bertrand

Publications and source records attributed to B Bertrand.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Quantification of aortic insufficiencies. Comparison between Doppler echocardiography and qualitative angiographic methods: apropos of a series of 60 consecutive patients].

Many doppler echocardiographic indices have been described for quantifying aortic regurgitation, posing the problem of the relative value of each. Therefore, the authors assessed the severity of aortic regurgitation in 60 consecutive patients (16 women and 44 men, mean age 56.7 years, range 7 to 84 years) by the four grades of Seller's classification with selective aortography. These results were compared with Doppler echocardiographic measurement of anterograde cardiac output (Qao), the pressure half time (PHT), diameter of the jet at its origin in M mode colour Doppler (DTM) and calculation of the regurgitant fraction (RF) by comparison of flow at the different cardiac orifices by a method previously described and validated in the author's laboratory with an interorifice correlation of 0.91 to 0.96 and confidence intervals at 95% of the order of 12%. The feasibility of doppler echocardiographic methods was good: 87.8% for PHT (58/66 patients), 90% for DTM (36/40 patients), 90.9% for Qao and RF (60/66 patients). The correlation with aortography was -0.65 (p < 0.01) for PHT; 0.91 (p < 0.01) for DTM, 0.80 (p < 0.01) for Qao and 0.92 (p < 0.005) for RF. However, there was a number of overlaps between Grades I and II and Grades III and IV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Transesophageal echocardiography in cardiac and paracardiac tumors. A multicenter study].

A multicentre study was undertaken to determine the diagnostic value of transoesophageal echocardiography (TOE) in tumours of the heart and pericardium. Forty-five cases were recensed: 24 myxomas, 1 fibroma, 1 hydatid cyst, 2 lymphomas, 3 sarcomas, 1 pleuropericardial cyst, 1 branchogenic cyst and 12 cardiac metastases. The diagnosis was made in all 45 cases by TOE but only in 35 cases by conventional transthoracic echocardiography which failed to recognise 2 myxomas, 1 hydatid cyst, 1 sarcoma, 2 paracardiac cysts and 4 cardiac metastases. The site of the tumour was identified 45 times by TOE compared with only 12 times by transthoracic echocardiography. However, the anatomical investigation of mediastinal tumours requires complementary computerised tomography. Moreover, TOE, like all other imaging techniques, is unable to predict the benign or malignant nature of the tumour, 1 leiomyosarcoma having been confused with a myxoma.

Adult↗
PubMed1995

Clinical efficacy of N-acetyl-aspartyl-glutamic acid nasal spray in children suffering from pollinosis: a double-blind multicentre study.

A double-blind, four-centre study was carried out in 66 children to compare the clinical efficacy and safety of N-acetyl-aspartyl-glutamic acid (NAAGA) and disodium cromoglycate (DSCG) nasal sprays. At similar dosage conditions (one puff per nostril, four times daily, for 3 weeks), no significant differences between the treatments were discernible in the primary efficacy parameters (scores, patients' and physicians' opinion). Both products induced statistically significant improvements in the nasal, ocular and total scores, but not in the respiratory (breathing) score. The hay-fever symptoms improved clinically in > 50% of the children after only two weeks with both treatments. The exact figures depended on the parameters considered. Thirteen out of 25 patients (52%) in the NAAGA group found the efficacy "good" or "excellent" at the end of the treatment period; the corresponding opinion in the DSCG group was expressed by 10 out of 24 patients (41.7%). Of the 28 patients that used the rescue medication, 12 (42.8%) were from the NAAGA group and 16 (57.1%) from the DSCG group. One patient on NAAGA treatment reported side effects, i.e. pruritus in the nose and sneezing.

Administration, Intranasal↗
PubMed1995

[External injuries of the larynx in the adult: apropos of a case].

Reporting one case of negliged laryngeal traumatism, the authors expose their laryngeal injuries attitude. They detail admitted classification and propose a management which is based on initial respiratory functions. In view of the case, as extreme situation, laryngeal subtotal surgery was the better management, because of association with polytraumatism, which not permitted earlier treatment.

Adult↗
PubMed1995

[A new X-ray source for medical imaging and radiotherapy research: synchrotron radiation].

Whether for diagnosis or therapeutic purposes, X-rays have many applications in medicine. Synchrotron Radiation sources open new perspectives. This has already been the case for a number of years in molecular and cellular biology where the scope of absorption and diffraction work has been greatly extended. This could also be the case for medical imaging and radiotherapy where the characteristics of the beam (collimation, stability, flux) allow new approaches in the energy range of radiological X-rays, namely between 30 keV and 100 keV. Such a source exists today in Grenoble, with the European Synchrotron Radiation Facility (ESRF). The opening of a beamline dedicated to medical research for whole European scientific community is planned for the end of 1996. This beamline, coupled with the "microbeam" beamlines, will cover medical imaging (angiography, tomodensitometry, microtomography, X-ray microscopy) as well as radiotherapy.

Animals↗
PubMed1995

Endonasal dacryocystorhinostomy: indications, technique and results.

Dacryocystorhinostomy (DCR) allows an obstructed lachrymal drainage system to be drained into the nasal fossa. Since the development of endonasal microsurgical techniques, the endonasal approach presents itself as an alternative choice to the conventional external approach. It is far less traumatic, yet as efficacious as the conventional approach, and avoids the need for a skin incision and the disruption of the medial canthal structures. Twenty-six patients suffering from lachrymal system obstruction underwent 28 endonasal dacryocystorhinostomies under microscopical (n = 25) or endoscopic control (n = 3). Pre-operative assessment included clinical symptoms (sac swelling, purulent secretions, epiphora) and outflow obstruction on X-rays (conventional dacryocystography and/or subtraction macrodacryocystography). Post-operatively, 23 DCR were free of symptoms. Two presented occasional epiphora and three were unsuccessful. The presence of pre-operative purulent secretions was significantly correlated with post-operative success and with lachrymal sac patency, which is also confirmed by X-ray examination (p<0.001). Thus in cases of purulent secretion with epiphora, X-ray examination is redundant and may be avoided. On the contrary, when epiphora is an isolated symptom, X-rays must be performed in order to determine where the obstruction is located and to provide information on lachrymal sac morphology.

Adolescent↗
PubMed1994

Atherosclerotic disease of the aortic arch and the risk of ischemic stroke.

BACKGROUND: Atherosclerotic disease of the aortic arch has been suspected to be a potential source of cerebral emboli. We conducted a study to quantify the risk of ischemic stroke associated with atherosclerotic disease of the aortic arch. METHODS: Using transesophageal echocardiography, we performed a prospective case-control study of the frequency and thickness of atherosclerotic plaques in the ascending aorta and proximal arch in 250 consecutive patients admitted to the hospital with ischemic stroke and 250 consecutive controls, all over the age of 60 years. RESULTS: Atherosclerotic plaques > or = mm in thickness were found in 14.4 percent of the patients but in only 2 percent of the controls. After adjustment for atherosclerotic risk factors, the odds ratio for ischemic stroke among patients with such plaques was 9.1 (95 percent confidence interval, 3.3 to 25.2; P < 0.001). Among the 78 patients who had brain infarcts with no obvious cause, 28.2 percent had plaques > or = 4 mm in thickness, as compared with 8.1 percent of the 172 patients who had infarcts whose possible or likely causes were known (odds ratio, 4.7; 95 percent confidence interval, 2.2 to 10.1; P < 0.001). Plaques of > or = 4 mm in the aortic arch were not associated with the presence of atrial fibrillation or stenosis of the extracranial internal carotid artery. In contrast, plaques that were 1 to 3.9 mm thick were frequently associated with carotid stenosis of > or = 70 percent. CONCLUSIONS: These results indicate a strong, independent association between atherosclerotic disease of the aortic arch and the risk of ischemic stroke. The association was particularly strong with thick plaques. Atherosclerotic disease of the aortic arch should be regarded as a risk factor for ischemic stroke and as a possible source of cerebral emboli.

Aged↗
PubMed1994

The Na+/H+ exchanger isoform 1 (NHE1) is a novel member of the calmodulin-binding proteins. Identification and characterization of calmodulin-binding sites.

The Na+/H+ exchange activity (NHE1 human isoform) is rapidly activated in response to growth factors and hyperosmotic stress. To get insight into the mechanism of NHE1 activation, we studied the direct interaction of a ubiquitous Ca(2+)-dependent regulatory factor, calmodulin (CaM) with NHE1. Binding experiments with CaM-Sepharose, as well as fluorescence measurements with dansylated CaM, revealed that the NHE1 cytoplasmic domain strongly binds CaM in a Ca(2+)-dependent manner. Fusion protein analysis with deletion mutants provided evidence for high (Kd approximately 20 nM) and intermediate (Kd approximately 350 nm) affinity CaM-binding sites located in neighboring regions of NHE1 (amino acids 636-656 and 657-700). To assess a regulatory role of CaM-binding sites, several cDNAs having deletion and point mutations in the high affinity site were generated and expressed in the exchanger-deficient fibroblast cell line PS120. Deletion and point mutations of positively charged residues of the high affinity CaM-binding site resulted in up to 50 and 80% reductions of cytoplasmic alkalinization caused by growth factors (alpha-thrombin, etc.) and 100 mM sucrose, respectively. In these mutants, the reduction in alkalinization was apparently in proportion to that of the CaM-binding ability. These results suggest that binding of Ca2+/CaM to the high affinity site is involved at least partly in the activation of NHE1 in response to different extracellular signals.

Amino Acid Sequence↗
PubMed1994

Mutation of calmodulin-binding site renders the Na+/H+ exchanger (NHE1) highly H(+)-sensitive and Ca2+ regulation-defective.

The ubiquitous plasma membrane Na+/H+ exchanger (NHE1) is rapidly activated in response to various extracellular signals. To understand how the intracellular Ca2+ is involved in this activation process, we investigated the effect of Ca2+ ionophore ionomycin on activity of the wild-type or mutant NHE1 expressed in the exchanger-deficient fibroblasts (PS120). In wild-type transfectants, a short (up to 1 min) incubation with ionomycin induced a significant alkaline shift (approximately 0.2 pH unit) in the intracellular pH (pHi) dependence of the rate of 5-(N-ethyl-N-isopropyl) amiloride-sensitive 22Na+ uptake, without changes in the cell volume and phosphorylation state of NHE1. Mutations that prevented calmodulin (CaM) binding to a high affinity binding region (region A, amino acids 636-656) rendered NHE1 constitutively active by inducing a similar alkaline shift in pHi dependence of Na+/H+ exchange. These same mutations abolished the ionomycin-induced NHE1 activation. These data suggest that CaM-binding region A functions as an "autoinhibitory domain" and that Ca2+/CaM activates NHE1 by binding to region A and thus abolishing its inhibitory effect. Furthermore, we found that a short stimulation with thrombin and ionomycin had apparently no additive effects on the alkaline shift in the pHi dependence of Na+/H+ exchange and that deletion of region A also abolished such an alkaline shift induced by a short thrombin stimulation. The results strongly suggest that the early thrombin response and the ionomycin response share the same activation mechanism. Based on these data and the results shown in the accompanying paper (Bertrand, B., Wakabayashi, S., Ikeda, T., Pouysségur, J., and Shigekawa, M. (1994) J. Biol. Chem. 269, 13703-13709), we propose that CaM is one of the major "signal transducers" that mediate distinct extracellular signals to the "pHi sensor" of NHE1.

Binding Sites↗
PubMed1994

Growth factor activation and "H(+)-sensing" of the Na+/H+ exchanger isoform 1 (NHE1). Evidence for an additional mechanism not requiring direct phosphorylation.

Growth factors stimulate the Na+/H+ exchange activity (NHE1 human isoform) and at the same time increase the phosphorylation state of the exchanger at serine residues. To determine the role of NHE1 phosphorylation, a set of deletion and point mutants has been generated. Functional characterization of deletion mutants expressed in fibroblastic cells revealed that the cytoplasmic region between amino acids 567 and 635 is required for both growth factor-induced cytoplasmic alkalinization and maintenance of high intracellular pH (pHi) sensitivity. In contrast to the loss of growth factor activation and pHi sensitivity caused by the deletion of amino acids 567-635, the same deletion had no apparent effect on the pattern of growth factor-induced phosphorylation. In addition, individual replacement of any of the serine residues between amino acids 567 and 635 with alanine also had no effect on growth factor activation of the exchange activity. Comparison of phosphopeptide maps for the wild type with those for the internal deletion mutant exchangers and the expressed cytoplasmic domain revealed that all major in vivo phosphorylation sites including growth factor-sensitive ones map to the cytoplasmic tail (amino acids 636-815). Deletion of these sites preserves high pHi sensitivity and reduces by only 50% growth factor-induced cytoplasmic alkalinization. Taken together, these data support the existence of a mechanism not requiring direct phosphorylation of NHE1, by which growth factor signals transmit to the "H(+)-sensor" and control the set point value of the exchanger. We propose that a regulatory factor(s) controls NHE1, presumably through its interaction with the critical cytoplasmic region prior to amino acid 635.

Cells, Cultured↗
PubMed1994

[Quantification of mitral valve insufficiency by Doppler echocardiography. Correlation with cine-angiography in 60 patients].

Non-invasive quantification of mitral regurgitation remains a clinical problem. The aim of this study was to assess a new methodology of Doppler echocardiographic assessment of the mitral regurgitant fraction. The study included 60 patients (average age 61 years) in sinus rhythm with mitral regurgitation. The cardiac output was measured by Doppler echocardiography at four sites: the aortic, pulmonary and mitral rings and at the tips of the mitral leaflets by a method previously validated and published. Using the average of the aortic and pulmonary cardiac outputs on the hand and the mitral cardiac output on the other, it was possible to calculate the regurgitant fraction: (mean mitral flow-mean aortic/pulmonary flow)/mean mitral flow. This was correlated with the Sellers angiographic grades of regurgitation. The results confirm this validated procedure: the correlation of aortic and pulmonary flows was good: r = 0.94. This also held true for mitral flow at the two sites: r = 0.96. The correlation between the Doppler echocardiographic regurgitant fraction and the angiographic estimation of the severity of mitral regurgitation was good: r = 0.89. There was a statistically significant difference between the Doppler echocardiographic regurgitant fractions corresponding to Sellers Grades I, II and III mitral regurgitation (p = 0.0001). This study shows that Doppler echocardiographic measurements of blood flow at different orifices of the heart applied to the quantification of mitral regurgitation is a reliable method, the use of which, with strict methodological criteria, may be proposed in everyday clinical practice.

Adult↗
PubMed1994

[Feasibility and accuracy of pulmonary blood flow measurement by Doppler echocardiography. Apropos of 100 consecutive cases].

One of the main advantages of Doppler echocardiography is the possibility of non-invasive measurement of blood flow at each valvular orifice. This method enables quantification of valvular regurgitation, the measurement of Qp/Qs in cardiac disease with atrial or ventricular shunts, and the interpretation of gradients and functional surface areas in valvular stenosis or prosthesis with respect to the underlying haemodynamics. In each of these application, the measurement of pulmonary blood flow is valuable as the reference blood flow, and even indispensible in cases of shunts. The authors' objective was to study the feasibility and accuracy of pulmonary flow measurement in 100 consecutive patients (40 women and 60 men, average age 56.7 +/- 17.5 years) with cardiac disease (82%) or healthy hearts (18%). A grading from A to D was accorded depending on the technical difficulty of the examination, each grade having three degrees: 1) difficulty of recording and poor quality Doppler spectrum, 2) difficulty of measuring orifice diameter by 2D echocardiography, 3) necessity of analysis of color coded anterograde flow to measure the pulmonary valvular orifice. Grade A was distributed to easily recordable measurements with no difficulty; grade B for measurements with one difficulty; grade C for measurements with 2 difficulties and grade D for investigations judged to be impossible or unreliable (3/3 criteria). The feasibility of measurement of the cardiac output at the pulmonary orifice was 88% (A:55%, B:25%, C:8%). The correlation between the pulmonary flow and reference measurements at the aortic and/or mitral valve and/or mitral annulus was 0.96. The average difference between the pulmonary and reference flow was 51 +/- 273 cc/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[What studies should be done in syncope?].

Fainting (short loss of consciousness) is a frequent reason for a consultation in a general practitioner's or cardiologist's office. Four main causes are recognized commonly: cardial with auriculo-ventricular block and arrhythmias, vascular in particular vaso-vagal syncopes, neurologic and other causes. In 38 to 47% of the patients no etiology is found: these are syncopal attacks of unknown origin. The first diagnostic step comprises noninvasive investigations. A 24-hour recording of the ECG or a 'long strip' improve the diagnostic rate by 10%. They are particularly useful for sick sinus syndromes. The head-up tilt-test has been developed recently. It is very useful for detection of vagovasal syncope and permits to understand the pathophysiology and the therapeutic consequences of these disorders. This test plays a particular role for the diagnosis of syncopes of unknown causes and shows in 24 to 75% of the cases pathologic results. Patients at high risk for ventricular arrhythmia can be recognized by ECG with high amplification. Doppler investigation of the neck vessels, however, seems to be of low diagnostic value in syncopes. Invasive measures are the last line resort. Electrophysiologic studies provide criteria that are well defined. They are useful for detection of ventricular dysrhythmias and conduction disorders. This latter approach is reserved to patients with negative noninvasive tests and in particular with cardiopathy. The approach to syncope and the power of noninvasive and invasive tests is thus well established. However, in a certain number of patients the cause for fainting is not disclosed. Fortunately mortality is low in this particular group.

Adult↗
PubMed1993

Cloning of alpha 2 chain of type VI collagen and expression during mouse development.

We have previously described the molecular cloning of a cDNA probe which detects a 6 kb mRNA termed pOb24. pOb24 mRNA appeared to be a marker of the preadipose state both in vitro and in vivo. A pOb24 genomic fragment was isolated and used to screen cDNA libraries in order to isolate the full-length pOb24 cDNA and to identify the corresponding protein. The screening yielded a new cDNA clone which detected a 3.7 kb mRNA species in addition to the 6 kb mRNA species. Sequences at the 3' end of the 6 kb and 3.7 kb mRNAs indicate that both mRNAs are generated from the same gene through the use of two different polyadenylation sites. The protein encoded by the 3.7 kb mRNA appeared to be homologous to the human alpha 2 chain of type VI collagen (A2COL6). The expression of the A2COL6 gene was not confined to adipose tissue; mRNA species can be detected in ovaries, adrenal glands and lungs but not in liver and skeletal muscle. The expression appeared specific for initial phase(s) of cell differentiation since it is parallel to that of the MyoD1 gene during muscle embryogenesis in vivo. In the myogenic C2C12 cell line, the A2COL6 gene exhibited the same regulation as MyoD1 and myogenin genes. These results indicate that A2COL6 gene expression is a marker of the preadipose state, but may also be a marker of other differentiation programmes such as that of muscle.

Amino Acid Sequence↗
PubMed1993

Temporary nasosinusal drainage and lavage in chronic maxillary sinusitis. Statistical study on 847 maxillary sinuses.

We report on 498 patients suffering from chronic maxillary sinusitis verified by sinusoscopy through the inferior meatus and by computed tomography of the sinuses, which permitted also the diagnosis of coexisting chronic ethmoidal sinusitis. The patients were treated by temporary drainage through a polyethylene drain tube left in place at the end of the antroscopy for daily lavage with saline solution and daily instillation in the sinus of thiamphenicol glycinate hydrochloride (similar to chloramphenicol) and N-acetyl-L-cysteine. We followed up 847 maxillary sinuses during the lavages according to 2 parameters: 1) recovery of a clean washout product at the macroscopic examination and 2) recovery of normal ostial patency as measured by sinusomanometry. We concluded that 1) the association with ethmoidal sinusitis does not significantly modify the treatment duration, and 2) fewer than 4% of the maxillary sinuses are likely to recover normal parameters after the 23rd day of lavage, and it is therefore useless to continue this treatment much longer. Of the maxillary sinuses, 36.25% were not submitted to any surgery. The results gained by the lavage technique have to be protected from recurrence by the treatment of general, focal, or local causes.

Acetylcysteine↗
PubMed1993

[Sudden deafness: a randomized comparative study of 2 administration modalities of hyperbaric oxygenotherapy combined with naftidrofuryl].

Hyperbaric oxygen therapy is one of the numerous therapies which have been proposed in the management of sudden deafness. It is presumptuous to claim the efficiency of any treatment in a pathology where both the origin and the actual rate of spontaneous recovery are unknown. The grounds of therapies are therefore empirical but the need of urgent therapy is dictated by ethics. This study compares the effects of hyperbaric oxygen therapy in two groups of patients; according ot their order in randomization the subjects were treated either at a rate of 1 session or 2 sessions per day. Hyperbaric oxygen therapy was associated with infusion of Naftidrofuryl to counteract the vasoconstrictive effect of increased oxygen pressure in blood. Steroids were also administered simultaneously to avoid, for the same reasons, cerebral oedema. Normovolemic hemodilution (Dauman et al. 1983) was systemically performed in all the patients preliminarily to hyperbaric oxygen therapy, in order to reduce the haematocrit and thus facilitate blood supply. The efficiency and the side effects were similar in the two groups, provided that some principles in the selection and the monitoring of the patients were respected. The rate of 2 sessions of hyperbaric oxygen therapy per day has obvious advantages in view of health policy, but it requires the hospitalization of the patient and should be restricted to the younger subjects.

Adult↗