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Biomedical subjects

P Lacroix

Publications and source records attributed to P Lacroix.

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

[Diaphragm of inferior vena cava associated with Budd-Chiari syndrome. Contribution of ultrasonography and color Doppler echocardiography].

We report the case of a young man presenting clinical features of portal hypertension of unknown origin. The ultrasonographic examination showed suprahepatic blockage signs leading to the diagnosis of Budd-Chiari syndrome caused by incomplete diaphragm of the inferior vena cava. The color Doppler examination suggested caval obstruction, showing an abrupt shift from a laminar to a bosterous flux. Secondly cavograms and surgery later confirmed the diagnosis.

Adult↗
PubMed1991

[Role of pelvi-perineal rehabilitation in the treatment of cavernous venous leakage].

The pathophysiological mechanisms, investigation and treatment of erectile dysfunction related to venous leakage are highly controversial. Although surgery appears to be the most logical treatment, the results obtained are very uncertain, regardless of the technique, and long-term improvements are rare. In this study, the authors propose an original management based on classical pelvi-perineal rehabilitation techniques combined with low-dose intracavernous injections. The preliminary results appear encouraging with about 50% improvement (improved or cured patients) in the various treated groups with a lasting result. The mechanism of action of rehabilitation is unclear, but this non-invasive technique should be considered prior to more aggressive management.

Electric Stimulation Therapy↗
PubMed1990

[Echocardiography by the transesophageal route. Technique and the main clinical indications].

Transoesophageal Doppler-echocardiography is a new heart imaging technique avoiding many of the problems which sometimes limit standard transthoracic exploration. The transducer, mounted on a fibroscope sheath, is introduced into the oesophagus and therefore lies in the immediate vicinity of the atrial complex, the mitral valve, the aortic valve and the different segments of the thoracic aorta. The examination can be carried out on ambulatory patients in the echocardiography laboratory. The main clinical indications of this technique are: studies of prosthetic valves (notably the mitral valve); detection of vegetations or annular abscesses in infective endocarditis; determination of an emboligenic focus after arterial embolism; study of the causative mechanism in mitral valve regurgitation; pathology of the thoracic aorta and, in particular, of aortic dissection. The usual lack of difficulty in skilled hands, the quality of the images obtained and the diagnostic value of information collected by this route explain why this relatively new technique has very rapidly progressed from evaluation to routine use in most echocardiography laboratories.

Aortic Diseases↗
PubMed1989

Left ventricular mass changes with nicardipine therapy in essential hypertension.

Eighteen hypertensive patients (13 males, 5 females; age 48 +/- 13; diastolic blood pressure greater than 95 mmHg), either previously untreated or who had been off treatment for more than 3 months, underwent M-mode echocardiography before (DO) and after (D90) 3 months of nicardipine therapy (60-90 mg/day). All echocardiograms were read blind, and left ventricular mass (LVM) was calculated (Devereaux's formula). Blood pressure was significantly reduced after 3 months from 167 +/- 15/102 +/- 8 mmHg on DO to 152 +/- 16/92 +/- mmHg on D90 (p less than 0.001). The reduction in LVM was not significant: 266 +/- 95 g on DO, 247 +/- 78 g on D90. There was a trend to a higher (although nonsignificant) LVM reduction in patients with left ventricular hypertrophy at entry (-11%, n = 11) than in patients without left ventricular hypertrophy (-2%), n = 7).

Adult↗
PubMed1989

[Sensitivity and specificity of temporal Doppler in Horton's disease].

170 patients with suspected temporal arteritis underwent Doppler investigation before temporal artery biopsy. Doppler study included the large cervical trunks, the ophthalmic system and analysis of the terminal branches of the external carotid with recording of the temporal territory on 3 points. Biopsy confirmed the diagnosis of temporal arteritis in 48 cases; it was negative in 122 cases. Doppler study and histological examination agreed in 137 patients (80%). There was disagreement in 33 cases (20%). The Doppler signal was pathological in 43 of the 48 cases of temporal arteritis (90%). There were 5 false negatives (10%). In subjects free from temporal arteritis, the Doppler examination was normal in 94 cases (77%), and was pathological in 28 cases (23%). The sensitivity of Doppler examination in the diagnosis of temporal arteritis was 90%, its specificity was 77%. The predictive value of a positive Doppler vis-a-vis the condition was only 61%. On the other hand, the predictive value of a normal examination was very high (95%). The high level of false positives is explained by technical problems, but especially by a high incidence of sometimes very stenosing senile arteritis. Finally, 3 of the 28 false positives (11%) subsequently developed authentic inflammatory arteritis. The authors conclude that a positive Doppler examination does not allow reliable prediction of the presence of temporal arteritis. On the other hand, a normal examination almost always allows the diagnosis of temporal arteritis to be excluded with a risk of error of less than 5%.

Aged↗
PubMed1988

[Obstacle to left ventricle ejection after mitral valvular replacement with a Carpentier-Edwards bioprosthesis. Apropos of 2 cases].

Impairment of the left ventricular ejection induced by a mitral prosthesis remains an infrequent complication, perhaps because it often is unrecognized. This complication would mainly be seen with ball prostheses or standard bioprosthesis used in mitral valve replacements with a small ventricle. Two cases have been recently reported during mitral valve replacement. The two patients were successfully re-operated upon, one after five weeks and the second immediately after the first procedure. A review of the literature enable to specify the etiology and diagnostic criteria with the assistance of Doppler-sonocardiography. Early re-operation may prevent death, often due to a post-operative myocardial dysfunction.

Bioprosthesis↗
PubMed1987

Effects of triethyltin on brain octopamines and their metabolism in the rat.

The effects of triethyltin given acutely on the cerebral level of p- and m-octopamines were studied in rats. These octopamines were reduced drastically in hypothalamus and brainstem, while noradrenaline and dopamine were only slightly decreased. No important changes were observed in the activities of tyrosine hydroxylase, dopamine beta-hydroxylase or monoamine oxidase. However, the activity of aromatic L-amino acid decarboxylase was significantly reduced. The addition of the inhibitor of dopa decarboxylase, Ro 44602, caused a total inhibition of this enzyme activity. These results are discussed in terms of the possible use of the triethyltin-induced cerebral oedema as a model for the study of some aspects of the phenolamine changes related to cerebral oedema processes.

Animals↗
PubMed1987

[Malignant lymphoma of the heart. Contribution of modern technics of medical imaging].

Although rarely encountered, tumours of the heart are now more easily and frequently diagnosed owing to the availability of non-invasive imaging methods, notably echocardiography. With echocardiography the cardiac extension of the tumour is perfectly visualized, but its connections with the mediastinum are less readily accessible. The case presented here of a female patients with a malignant lymphoma involving the heart (right ventricle and atrium, pericardium) and the mediastinum illustrates the complementary nature of echocardiography, computerized tomography and magnetic resonance imaging.

Aged↗
PubMed1987

[Value of the stop-test in the diagnosis of detrusor hyperactivity. Concept of the isometric zone. Preliminary study of 30 cases].

The authors propose a new pathophysiological and diagnostic approach to detrusor hyperactivity by the study of the isometric pressure obtained during the stop-test. This test consists of the sudden interruption of micturition by voluntary contraction of the striated urethral sphincter, resulting in sudden contraction of the bladder against the closed sphincter. This isometric contraction is equal to 20 to 30 cm of water. The increase in the pressure (delta P) between the basal micturition pressure and the absolute value of the isometric pressure (P iso) reflects the contractile force of the detrusor. The progressive return to the basal micturition pressure reflects the relaxation of the detrusor, which is the sum of visco-elastic properties and the mechanisms of cortico-sub-cortical neurological inhibition. Calculation of the isometric area (delta P X T/2), where T represents the time taken to return to the initial pressure, allows cases of central neurological hyperactivity (isometric area always greater than 100) to be distinguished from cases of detrusor hyperactivity of mechanical origin (isometric area less than 80). These data have been confirmed in a series of 30 patients.

Adolescent↗
PubMed1986

Studies on pristinamycin synergism in Staphylococcus aureus.

Binding experiments were performed with both components of the pristinamycin complex (pristinamycin IA (PIA) and pristinamycin IIA (PIIA] using ribosomes from sensitive and resistant Staphylococcus aureus. Fluorescence polarization was used to measure PIA binding. The results obtained show a direct correlation between inhibition, synergy and the enhancement of the affinity of PIA for its receptor in the presence of PIIA. The uptake of PIA by intact cells seems to be directly correlated with affinity between PIA and ribosomes, a phenomenon which is probably shared with the macrolide antibiotics.

Anti-Bacterial Agents↗
PubMed1985

Sudden death and experimental acute myocardial infarction.

Acute myocardial ischemia was produced by ligature of the anterior descending coronary artery on 658 dogs in 3 separate laboratories. Overall, 12% of the dogs died within the first hour (instantaneous death) and 25% within the first 24 hours (sudden death). The sudden death rate was significantly related to the logarithm of the weight of the dogs in the range studied. It varied widely if values from small series, comprising the same number of dogs, were considered. Values became less dispersed as the size of the series increased. In series of 10 dogs, sudden death rates ranged from 0 to 70%, whereas in series of 100 dogs the range was 14 to 36%. Stable values were obtained for 50 to 60 dogs per series. Accordingly, reliable assessment of preventive measures can be made only with experimental series of at least this size.

Animals↗
PubMed1985

[Water-soluble derivatives of factor IA of pristinamycins. Interaction with the bacterial ribosome].

The IA component of pristinamycins is a depsipeptide with a bacteriostatic effect on Gram positive bacteria. IA is made bactericidal by association with the IIA component of pristinamycins. Use of IA is limited because of its poor solubility in water. For this reason several water soluble IA derivatives have been synthesized. As for IA, these derivatives are fluorescent, a property used to study the binding of each compound to bacterial ribosomes of Escherichia coli (G-) and Staphylococcus aureus (G+). Two different techniques were used: direct study of fluorescence of the ribosome-antibiotic complex, and study of polarization of the fluorescence of the antibiotic bound to its receptor site. In addition to determination of binding parameters, these techniques can evaluate molecular synergy between pristinamycin IA (PIA) derivatives and pristinamycin IIA (PIIA) derivatives. MICs for the tested molecules correlate strongly with their binding parameters.

Chemical Phenomena↗
PubMed1985

[Trapped popliteal arteries. Incidence, epidemiology, therapeutic considerations].

The trapped popliteal artery syndrome is an extrinsic dynamic compression of the vascular structures in the popliteal fossa by the surrounding fibromuscular structures. The condition mainly affects the popliteal artery resulting in atypical intermittent claudication because it often occurs in young and active patients. The arterial lesions are initially purely extrinsic and dynamic; sometimes they progress to thrombosis, embolism or aneurysm due to jet lesions. The diagnosis is obtained by radiology in the uncomplicated forms by showing compression or complete occlusion of the artery during contraction of the gastrocnemius and quadriceps muscles. Doppler studies of the posterior tibial artery may also demonstrate the condition during these manoeuvres. The epidemiological study was performed in 199 medical students and 80 athletes. A positional abolition of the posterior tibial artery was demonstrated in 39 students (19%) and 12 athletes (15%). The entrapment was commoner in females (24%) than males (13%). It was observed more frequently in dancers, cyclists and basket ball players: 12 control digitised intravenous angiographies were performed; the diagnosis was confirmed in 11 cases. Several anatomical anomalies of the popliteal fossa may give rise to this condition. The commonest is a deviation of the artery within the internal head of the gastronemius muscle; compression by the soleus or fibro muscular bands arising from the semi-tendinous or semi-membranous have been described. The treatment is surgical in very symptomatic or complicated cases; uncrossing the artery associated with venous grafting in cases of thrombosis are the procedures of choice.

Constriction, Pathologic↗
PubMed1984

Antibiotic uptake by bacteria as measured by partition in polymer aqueous phase systems.

Polyethyleneglycol/dextran and polyethyleneglycol/salt two-phase systems are used to measure the entry of antibiotics into Escherichia coli and Staphylococcus aureus cells. Aminoglycosides, macrolides, a quinolone, and a cycline were assayed. The method is simple and rapid and eliminates the problems encountered with filters, especially nonspecific binding; it allows rapid uptake kinetics to be measured.

Anti-Bacterial Agents↗
PubMed1984

Pristinamycin accumulation by Staphylococcus aureus.

Pristinamycins IA and IIA (PIA and PIIA) accumulation by Staphylococcus aureus has been studied with two hydrogenated analogs, (H2)PIA and (H2)PIIA. Rapid accumulation of both antibiotics at 37 degrees C is observed and internal concentrations can reach up to 58-fold the external concentration; this accumulation cannot be reduced by either metabolic inhibitors or tetracycline. The synergistic activity of pristinamycins IA and IIA is not observed at the bacterial accumulation level. We propose that pristinamycins enter into bacteria by a passive diffusion process and that the internal concentration is maintained by binding of the antibiotic to the bacterial ribosomes.

Anti-Bacterial Agents↗