Search PubMed⌕ Search

Biomedical subjects

A Bertrand

Publications and source records attributed to A Bertrand.

At least 19 recordsLinked to original sources
PubMed1995

Sympathectomy does not modify the levels of dopa or dopamine in the rat dorsal root ganglion.

In the present study we report on the levels of dihydroxyphenylalanine (DOPA), dopamine and their metabolites, 3-O-methyl-DOPA, homovanillic acid and dihydroxyphenylacetic acid, in the dorsal root ganglion (DRG) where dopaminergic sensory neurons have recently been identified. HPLC with electrochemical detection was used. Chemical sympathectomy, induced by daily injection of 30 mg/kg/sc of guanethidine over 4 days, did not modify these levels. DOPA, dopamine and their metabolites were also detected in the dorsal root in both intact and sympathectomized rats. The present results show that in the DRG, DOPA and dopamine do not derive from sympathetic nerves, and agree with previous reports suggesting that there is a peripheral dopaminergic sensory innervation. In addition the identification of 3-O-methylDOPA, the extraneuronal metabolite of DOPA is not only the precursor of dopamine in the DRG but may be released from DRG cells. The high 3-O-methyl-DOPA/DOPA ratio found in the DRG and the dorsal root suggests that DOPA could play a role as neurotransmitter or modulator in the peripheral sensory innervation, as it has been proposed for the central nervous system and the sympathetic system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Influence of the sympathetic nervous system in the development of abnormal pain-related behaviours in a rat model of neuropathic pain.

This study evaluated the effect of surgical sympathectomy on pain-related behaviours in a well established model of peripheral mononeuropathy produced by loose ligatures around the common sciatic nerve in the rat. Behavioural abnormalities include spontaneous abnormal position of the hindpaw after the nerve constriction, indicative of "spontaneous pain", and changes in responses to mechanical or thermal stimuli applied to this paw. These changes are usually maximal at week 2 after the surgery, stable until weeks 3-4, and disappear between weeks 8 and 12. To assess the role of the sympathetic nervous system in the development and persistence of these abnormalities, four groups of rats were behaviourally tested: (i) rats receiving a complete sham surgery, (ii) rats with a sciatic nerve constriction produced by loose ligatures around the common nerve trunk plus a sham sympathectomy, (iii) rats receiving a lumbar sympathectomy with a sham nerve ligature, and (iv) rats receiving a simultaneous surgical lumbar sympathectomy and a sciatic nerve constriction. The efficacy of the sympathectomy was assessed by the measure of the noradrenaline level in the sciatic nerve. Sympathectomy reduced selectively or even prevented the abnormal reaction to cold temperature and to heat (45 degrees C) in rats with a peripheral mononeuropathy. In contrast, the abnormal reaction to mechanical pressure was not influenced, and the behavioural abnormalities indicating spontaneous pain were still present. Sympathectomy alone resulted in a reduction of the vocalization threshold to pressure on both hindpaws, but also a short-lasting increased tolerance to cold immersion. This study confirms the selective role of the sympathetic nervous system in affecting the development and maintenance of some abnormal pain-related behaviours to thermal stimuli in rats with a moderate, but persistent, constriction of one sciatic nerve.

Animals↗
PubMed1995

Effects of age and level of work experience on occurrence of accidents.

Results of a research study on the effects of age and work experience and their interaction on the occurrence of accidents in an agro-food sector are described. Three different levels of experience and six age groups were examined. Age and work experience significantly affected frequency and seriousness of accidents. A study of these two factors jointly shows that considerably higher rates of frequency and seriousness are found for the youngest and oldest subjects with low work experience. These analyses enable us to put forward several hypotheses concerning the mechanisms in the occurrence of accidents.

Accidents, Occupational↗
PubMed1995

Thallium-201 rest-reinjection and iodine-123-MIHA imaging of myocardial infarction: analysis of defect reversibility.

UNLABELLED: Rest SPECT imaging with [123I]-16-iodo-3-methylhexadecanoic acid (MIHA) frequently shows an increased level of uptake in areas with irreversible defects on exercise 201TI SPECT. Such mismatch patterns between flow (201TI) and metabolic (MIHA) tracers might correspond to areas with ischemic but viable myocardium misidentified by 201TI imaging. METHODS: Eighty-three patients with myocardial infarction underwent exercise SPECT 201TI with rest-reinjection and rest SPECT with MIHA. Defect areas on the exercise images were reversible on MIHA but not on 201TI reinjection images that were determined visually. The presence and extent of these areas were quantified from normalized uptake values for both tracers. RESULTS: In areas with irreversible 201TI reinjection defects, MIHA detected exercise defect reversibility in 59% of patients. In areas with irreversible 201TI reinjection defects, the extent of visually determined defect reversibility on MIHA scans was related to the quantified extent of areas with 201TI uptake > or = 50% of normal; the correlation, however, was weak. In 86% of patients, areas with > or = 50% 201TI uptake were larger than those that were reversible on MIHA. CONCLUSION: After myocardial infarction, rest SPECT with MIHA often enables visual detection of increased uptake in areas with irreversible 201TI reinjection defects.

Exercise Test↗
PubMed1995

Myocardial perfusion imaging with technetium-99m-Tc NOET: comparison with thallium-201 and coronary angiography.

UNLABELLED: We compared TcN-NOET [bis(N-ethoxy, N-ethyl dithiocarbamato)nitrido 99mTc] and 201Tl images to estimate the utility of this compound in the detection of coronary artery disease (CAD). METHODS: Twenty-five patients undergoing cardiac catheterization had stress-redistribution-reinjection 201Tl SPECT imaging, stress-delayed (2, 4 and 6 hr postinjection) and rest-delayed (4 hr postinjection) TcN-NOET SPECT imaging. RESULTS: Nineteen patients had coronary stenosis > or = 50% and six were normal. Stress TcN-NOET and 201Tl imaging were concordant for the presence of CAD in 22/25 patients (88%, kappa = 0.76 +/- 0.20). The overall sensitivity of TcN-NOET SPECT imaging was 74% (14/19 patients) and 68% (13/19 patients) for 201Tl SPECT imaging. The specificity was 100% (6/6 patients) for both techniques. The overall agreement of TcN-NOET and 201Tl for the presence of disease in individual coronary arteries was 96% (72/75 arteries, kappa = 0.92 +/- 0.16). Segmental analysis of stress images showed a concordance in 211/225 segments (94%, kappa = 0.82 +/- 0.09). Comparison of the 4-hr images showed a concordance between 201Tl and TcN-NOET in 21/23 patients. Following TcN-NOET injection at rest, seven patients had a defect on the initial images, which had normalized 4 hr postinjection in four patients (57%). CONCLUSION: Perfusion imaging with TcN-NOET and 201Tl gives comparable diagnostic information in patients undergoing exercise testing for assessment of CAD. Because of the normalization of myocardial activity 4 hr after injection in some patients, we conclude that TcN-NOET is a potential technetium compound equivalent to 201Tl.

Adult↗
PubMed1994

[Antibiotic treatment of brucellosis].

Forty years after active drug therapy was defined, the treatment of brucellosis still raises the problem of selecting the correct antibiotic and the duration of treatment. Indeed, requirements may be complex since one must select antibiotics which are active in vitro and which diffuse readily into the tissues and into the cells without developing bacterial resistance. Prescriptions must also be long enough, not only to achieve cure, but also to eliminate the Brucella strain. Antibiotics must be found which meet this last criteria yet do not lead to toxic effects or impair the patient's own immune response. Acute septicemic brucellosis in adult men and non-pregnant women has been effectively treated with the following three regimens: 1) doxycycline 200 mg/d and rifampin 900 mg/d orally for 45 days; 2) doxycycline 200 mg/d orally for 45 days and streptomycin 1 g/d IM for three weeks; 3) TMP-SMZ 320-1600 mg/d and rifampin 900 mg/d orally for 45 days. All regimens require a combination of two antibiotics and a prolonged course for total recovery, although casual relapses may occur. The doxycycline-rifampin combination shows the most favorable efficacy/safety ratio, and either antibiotic alone was used successfully in pregnant women by some investigators. The TMP-SMZ-rifampin combination is recommended in children below 8 years of age. Osteoarticular infections can be treated with doxycycline plus rifampin for 3 to 6 months, and streptomycin during the first 2 or 3 weeks. In nervous system complications, the preferred treatment is TMP-SMZ plus rifampin for 3 to 6 months. Brucellar endocarditis should be treated parenterally with streptomycin or gentamycin combined with TMP-SMZ, rifampin and doxycycline, and often requires valvular replacement. Many other antibiotics have been used with good clinical responses in the treatment of brucellosis, e.g., chloramphenicol, erythromycin, ampicillin, and more recently cephalosporins, thienamycin and fluoroquinolones; however, more cases have to be studied before any of these agents is definitely chosen for the treatment of brucellosis.

Adult↗
PubMed1994

Serial evaluation of dilated cardiomyopathy with exercise thallium-201 tomography: correlation with the evolution of left ventricular parameters.

The purpose of this prospective study was to correlate (1) the initial findings of exercise thallium-201 tomography with the evolution of left ventricular parameters at long term follow-up in patients with dilated cardiomyopathy and (2) the changes of exercise thallium-201 tomography repeated 1 year later. We studied 19 men with dilated cardiomyopathy and normal coronary angiogram. Two patients died and three patients had heart transplantation during follow-up. The other 14 patients were assessed at baseline and 1-year follow-up. Thallium-201 tomograms were divided into 20 segments for each patient. Two groups were defined according to the evolution of left ventricular ejection fraction: group 1 (n = 7) had unchanged or decreased ejection fraction at follow-up (24 +/- 11% at baseline versus 22 +/- 11% at follow-up, ns) and group 2 (n = 7) had improved ejection fraction at follow-up (25 +/- 9% at baseline versus 49 +/- 8% at follow-up, P < 0.03). The number of total abnormal segments at stress were not statistically different at baseline between groups 1 and 2, and in group 1 between baseline and follow-up. Group 2 at follow-up had a reduced number of total abnormal segments (P < 0.03). The percentage of reversibility was similar in both groups at baseline and follow-up. On exercise thallium-201 tomography, neither the presence nor the reversibility of stress myocardial perfusion abnormalities can predict improvement of left ventricular ejection fraction in dilated cardiomyopathy. However, regression of dilated cardiomyopathy is accompanied by a reduction of stress myocardial perfusion abnormalities.

Adult↗
PubMed1994

Comparison of T1 estimation techniques in cardiac MRI.

We have shown that the use of a simple combination of inversion recovery/spin-echo (IR/SE) sequences provides undeniably superior precision in quantitative in vivo myocardium T1 estimation than the standard multiple spin-echo approach. On a group of 25 healthy subjects, the T1 dispersion was, respectively, 3.8% for the IR/SE combination and 19.6% for the best SE pair combination. Moreover, repeated measurements were carried out on seven of the volunteers in order to assess T1 reproducibility. The mean intra-individual T1 precision was found to be 2.8% for the IR/SE pair and 20.0% for the best SE pair. The in vivo imaging work was supported and corroborated by a thorough treatment of the theoretical T1 errors. We also highlight the importance of quality control in quantitative MRI; a correction being required in the SE sequences to bring measured signal intensities into line with those predicted from simple theory.

Adult↗
PubMed1993

Radionuclide assessment of regional differences in left ventricular wall motion and myocardial perfusion in idiopathic dilated cardiomyopathy.

Regional variations in left ventricular contractility and myocardial perfusion are frequent in idiopathic dilated cardiomyopathy and might result from an increase in left ventricular wall stress responsible for regional wall motion abnormalities. The aim of the study was to perform radionuclide studies in patients with idiopathic dilated cardiomyopathy to assess regional left ventricular wall motion and myocardial perfusion abnormalities in this myocardial disease. We studied 29 men referred with idiopathic dilated cardiomyopathy and normal coronary angiograms. Rest radionuclide left ventriculography and exercise thallium-201 tomography were performed in all patients. The thallium-201 tomograms were divided into 20 segments for each patient. Mean left ventricular ejection fraction was 27 +/- 11%; 17 patients had diffuse hypokinesia (mean left ventricular ejection fraction: 24 +/- 9%) and 12 patients had predominant regional hypokinesia (mean left ventricular ejection fraction: 32 +/- 12%). Of all 580 tomographic segments, 186 had a reduction of thallium-201 uptake at exercise. Among them, reversibility was found in 53%. On the whole, 68% (158/232) of anterior, inferior and apical segments had a perfusion abnormality, compared with 8% (28/348) of septal and lateral segments (P < 0.0001). Left ventricular wall motion and myocardial perfusion abnormalities are heterogeneous and not evenly distributed in dilated cardiomyopathy. The alterations are predominant on the myocardial regions delineating the antero-posterior axis of the left ventricle. These findings suggest the possible role of increased left ventricular wall stress on this axis.

Cardiomyopathy, Dilated↗
PubMed1993

A non-comparative, multicentre study of cefepime in the treatment of serious bacterial infections.

Multi-resistant strains of Gram-negative bacteria are rapidly emerging as a frequent cause of serious bacterial infection in the hospital environment. Effective treatment must include an antibiotic with activity against these organisms. In an open multicentre study, cefepime was evaluated as empirical therapy in 156 hospitalized patients (mean age 57 years) with serious infection of the urinary tract (n = 43), lower respiratory tract (n = 101) and skin and soft tissue (n = 12). In 18 patients, septicaemia/bacteraemia was also diagnosed. Cefepime, 2 g bd, was administered for a maximum of 16 days (mean 8). Of 98 pathogens isolated, 75 were Gram-negative and 23 were Gram-positive species. Ninety-four of the pathogens were susceptible to cefepime, including multi-resistant isolates such as Pseudomonas aeruginosa and Enterobacter cloacae. The overall clinical cure rate, excluding septicaemia/bacteraemia, was 92% (94/102); the corresponding bacterial eradication rate was 95% (52/55). In patients with septicaemia/bacteraemia, the clinical cure rate was 87% (13/15) despite eradication of 100% (11/11) of the assessable pathogens. Cefepime was well-tolerated, although 14 (9%) patients experienced local intolerance at the infusion site. Other drug-related adverse events were reported in six (4%) patients and included diarrhoea, pruritus, rash and urticaria. Cefepime is safe and effective as empirical treatment for serious infections commonly found in the hospital setting. Clinical cure and bacterial eradication can be achieved with a convenient bd dosing schedule.

Adolescent↗
PubMed1993

A comparative study of cefepime and ceftazidime in the treatment of community-acquired lower respiratory tract infections.

Antibiotic treatment for community-acquired pneumonia must target Gram-positive pathogens, especially frequently isolated organisms such as Streptococcus pneumoniae. The severity of community-acquired pneumonia is often related to underlying factors. Occasionally it may be complicated by staphylococcal or Gram-negative bacillary infection. We have compared the safety and efficacy of cefepime 1 g bd with ceftazidime 1 g tds as empirical treatment in adults with community-acquired lower respiratory tract infections (LRTIs). One hundred and thirty-one patients with moderate to severe LRTIs were randomized to two treatment groups: 87 received cefepime and 44 received ceftazidime. The treatment groups were comparable with regard to sex, age and treatment duration. Of the 116 pathogens isolated, 57 were Gram-positive (46 strains of S. pneumoniae) and 59 were Gram-negative (33 strains of Haemophilus influenzae). Of the 111 patients evaluated, clinical cure rates were 87% (65/75) in the cefepime group and 86% (31/36) in the ceftazidime group. Pathogen eradication rates were 95% (74/78 and 36/37, respectively) in both groups. Both drugs were well tolerated and the incidence of adverse events in each group was comparable. Cefepime 2 g per day (1 g bd) was as safe and effective as ceftazidime 3 g per day (1 g tds) in the treatment of community-acquired LRTIs.

Adult↗
PubMed1992

In vitro antibody secretion by peripheral blood mononuclear cells as an expression of the immune response to Brucella spp. in humans.

We developed an assay to detect antibodies spontaneously secreted in vitro by peripheral blood mononuclear cells (PBMC) against Brucella spp. High levels of anti-Brucella immunoglobulin G (IgG) and/or IgM and/or IgA antibodies were detected in the cell supernatant solution of PBMC cultures for 12 patients suffering from acute or focalized brucellosis and for 5 patients recently vaccinated against brucellosis. This spontaneous in vitro antibody production disappeared 5 to 20 months after onset of clinical signs and 20 to 27 days after vaccination. The transient character of this anti-Brucella antibody production by PBMC is consistent with a temporary in vivo stimulation of the immune system by Brucella antigens. Detection of this secretion could improve the diagnosis of evolutive brucellosis.

Adult↗
PubMed1992

Measurement of lymphatic flow variation by noninvasive method cases of lymphedema.

The purpose of this study was to measure the variations of lymphatic flow. A noninvasive isotopic method was used to achieve a functional exploration of lymphatic circulation. Fifteen subjects were used in the study: 10 healthy subjects and 5 patients with lower extremity lymphedema. A first subcutaneous injection of technetium 99m rhenium sulfate (99mTc) was performed in the first interdigital space of both feet. The radioactivity was recorded in two places: the first one on the inguinal site by a gamma camera; the second, below the first, on the precordial site by a multichannel analyzer. With the two types of recording procedures, it was possible to obtain a curve that showed the amount of radioactivity in relation to time. In order to obtain a muscular activity fifty-five minutes after the injection, each subject or patient spent ten minutes on an ergometric bike. A second subcutaneous injection was performed one week later, but prior to the injection, the subject or patient took orally 1800 mg of heptaminol adenosine phosphate (HAP) per day for three days. The radioactivity recording was made under the same conditions as with the muscular activity. The statistical results of the experiment without treatment on the two types of recording show that in the healthy subjects the amount of radioactivity increased during muscular activity. Moreover, the treatment indicated higher radioactivity values, which remained at a higher level. However, the muscular activity performed by a patient was unable to increase the radioactivity. On the other hand, the drug gave radioactivity values that were higher than the previous values of the first curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Monophosphate↗
PubMed1991

Characterization of a protein binding sequence in the promoter region of the 16S rRNA gene of the spinach chloroplast genome.

By means of mobility-shift assays and Exonuclease III mapping we have determined a 14 bp sequence (named CDF2 binding site) located in front of the 16S rRNA initiation start site which is protected by a spinach chloroplast extract. This region does not include neither one of the two '-35' nor of the two '-10' E. coli-like promoter elements which are recognised by E. coli RNA polymerase in vitro. The CDF2 binding site is specifically recognized by two small polypeptides which migrate corresponding to 35 and 33 kDa respectively as shown by UV cross-linking experiments. In vivo transcription initiation of the 16S rRNA gene occurs 13 nucleotides downstream of the 14 bp sequence and is different from the transcription start site which is used by E.coli polymerase in vitro.

Base Sequence↗
PubMed1991

Evolution of myocardial ischemia and left ventricular function in patients with angina pectoris without myocardial infarction and total occlusion of the left anterior descending coronary artery and collaterals from other coronary arteries.

Repeated episodes of myocardial ischemia might lead to progressive impairment of left ventricular (LV) function. This radionuclide study assessed myocardial ischemia and LV function several years after documented coronary occlusion without myocardial infarction. Over 5 years, 24 consecutive patients, who underwent cardiac catheterization for angina pectoris without myocardial infarction, had isolated total occlusion of the left anterior descending coronary artery with well-developed collateral vessels. Five patients were successfully treated by coronary bypass grafting and 3 by coronary angioplasty. Among the 16 medically treated patients, 1 was lost to follow-up and 1 died (extracardiac death). The mean (+/- standard deviation) follow-up (14 patients) was 48 +/- 15 months. At follow-up, 8 patients still had clinical chest pain, 11 received antianginal therapy, 4 patients had no stress ischemia and the other 10 had greater than or equal to 1 sign of stress ischemia. All patients had a normal LV ejection fraction at rest (mean 60 +/- 3%; range 55 to 65%). Collateral circulation preserves LV function at the time of occlusion and, in some cases, prevents the development of myocardial ischemia; in patients with persisting myocardial ischemia after well-collateralized coronary occlusion, LV function is not impaired at long-term follow-up.

Aged↗