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Biomedical subjects

M Bazin

Publications and source records attributed to M Bazin.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Acute right ventricular failure. Treatment with dobutamine].

Acute right ventricular failure is commonly observed during respiratory intensive care, particularly in patients suffering from massive pulmonary embolism, chronic obstructive pulmonary disease or adult respiratory distress syndrome. The haemodynamic effects of a continuous dobutamine infusion at the rate of 9.4 +/- 3.7 micrograms/kg/min were assessed in a group of 15 patients with acute and isolated right ventricular failure, as evidenced by haemodynamic and two dimensional echocardiographic measurements. This inotropic agent induced at 37% increase in mean cardiac index and a 25% increase in mean stroke index, with only a 10% increase in mean heart rate. Moreover, measurement of the right ventricular ejection fraction by a thermal dilution technique performed in 10 patients demonstrated that dobutamine consistently and significantly increased right ventricular systolic function and also significantly reduced right ventricular end-diastolic tension. In conclusion, it appeared that dobutamine was able to improve circulatory status in patients with acute right heart failure or various origins.

Acute Disease↗
PubMed1984

Circulatory failure in acute pulmonary embolism.

Circulatory failure occurs in about 10% of patients with pulmonary embolism, resulting from a massive obstruction of the pulmonary arterial bed. Hemodynamic and respiratory features are well established; they involve precapillary pulmonary hypertension, low cardiac output state, elevated filling pressure for the right ventricle, and venous admixture. More recently, two-dimensional echocardiography permitted the visualization of pulmonary artery and right heart enlargement, reduced right ventricular ejection fraction, and tricuspid regurgitation. Evaluated by this latter means, left ventricular systolic function appeared unchanged, but diastolic function might be reduced by septal bulging.

Cardiac Output, Low↗
PubMed1983

Endothelial cell coat modifications in rat thoracic aorta. Effect of ovariectomy and cigarette smoke.

The effects of acute cigarette smoking and bilateral ovariectomy on the thickness of rat aortic cell coat (Con A) were investigated. Ovariectomized rats showed a significant increase in the thickness of the cell coat. When cigarette smoking was combined with ovariectomy the thickness of the reaction product was similar to controls. Cigarette smoke without ovariectomy resulted in a decreased thickness, but these changes were not significant.

Animals↗
PubMed1982

[Outcome of the adult acute respiratory distress syndrome. Predictive value of a severity index calculated from arterial oxygenation (author's transl)].

A retrospective study was carried out a group of 50 adult patients who had presented with acute respiratory distress syndrome and had all been treated by mechanically controlled ventilation with positive end-expiratory pressure (PEEP). The predictive value of the so-called "severity index" was tested. This index, which is used from the second day of treatment onward to predict with strong probability whether the lung lesions will subside or develop, is obtained from the PaO2 after corrections taking into account the FiO2 and the PEEP level. The study also supplied information on the outcome of lung lesions which may result in one of four possible courses of about equal frequency: the patient may either die or be cured rapidly after less than a week of assisted ventilation, or he may die at a later date or be cured slowly after more than a week of assisted ventilation.

Female↗
PubMed1982

One-electron photoreduction of bacterial cytochrome P-450 by ultraviolet light. I. Steady-state irradiations.

Bacterial ferric cytochrome P-450 can be photoreduced by ultraviolet light in presence of camphor as shown by the formation of the ferrous cytochrome P-450--CO complex absorbing at 446 nm in CO-saturated solutions. This photoreduction can only be performed with wavelengths (lambda less than 315 nm) corresponding to the absorption of light by aromatic residues and in particular, tryptophan. The primary process leading to the photoreduction is thus the photoionization of tryptophan residue(s) near the active site of the protein as deduced from competitive electron scavenging with N2O. In agreement with results obtained with chemical reduction, the quantum yield of photoreduction is proportional to the content of the high-spin state of the ferric cytochrome P-450 solution. It is also shown that the camphor concentration affects the CO binding.

Camphor↗
PubMed1982

One-electron photoreduction of bacterial cytochrome P-450 by ultraviolet light. II. A study using laser flash photolysis of the dynamics of the reduction of bacterial cytochrome P-450 in the presence of carbon monoxide. The role of the protein conformation.

The intramolecular photoreduction of the bacterial cytochrome P-450 demonstrated by the formation of the complex of reduced cytochrome m with camphor and CO has been studied by photolysis with a laser flash at 265 nm. This photoreduction of the heme follows the photoionization of a proximal aromatic amino acid residue and especially tryptophan in the nanosecond time scale as evidenced by the N2O effect on the reduction yield. However most of the hydrated electrons released in the solution do not react with the ferric porphyrin. In agreement with steady state studies, the quantum yield for formation of the complex of reduced cytochrome m with camphor and CO is proportional to the concentration of the high-spin species. The low-spin ferric porphyrin is thus not reducible by photoejected electrons. It is also shown that the growth kinetics of the transient absorbance at 446 nm characterizing the complex of reduced cytochrome m with camphor and CO correspond to a structural change affecting the protein and not to the formation of the complex of CO with the camphor-bound reduced cytochrome in which occurs on a shorter time scale in the present experimental conditions.

Carbon Monoxide↗
PubMed1981

Controlled ventilation with best positive end-expiratory pressure (PEEP) and high level PEEP in acute respiratory failure (ARF).

We assessed hemodynamics, total lung and chest wall compliance (CT) and gas exchange using two different levels of PEEP during controlled ventilation in two different groups of patients with ARF; in the first group (Group 1, 12 patients) chest X-Rays showed a symmetrical pattern of bilateral alveolar infiltrates; in the second group (Group 2, 5 patients) chest X-Ray showed a asymmetrical pattern with unilateral lobar consolidation. A first level of PEEP (best PEEP = 9 +/- 3 cm H2O) produced an improvement in CT and in gas exchange with a slight decrease in cardiac index in both groups; but improvement in PaO2 (from 64 +/-33 to 122 +/- 76 torr, p less than 0.001 in Group 1, and from 76 +/- 39 to 91 +/- 33 torr, p less than 0.05 in Group 2) and decrease in QS/QT were not as well marked in Group 2 as i Group 1. A second level of PEEP (high level PEEP: 20 +/- 4 cm H2O) produced a sharp decrease in CT and required hemodynamic support in each case (blood volume expansion with or without Dopamine infusion) to maintain cardiac index within a normal range. In Group 1 this high level PEEP produced a greater improvement in gas exchange (PaO2 increased from 122 +/- 76 to 194 +/- 76, p less than 0.01) but in Group 2 it had a deleterious effect, producing a decrease in PaO2 (from 91 +/- 33 to 76 +/- 41 torr, p less than 0.05), and an increase in QS/QT; with this higher PEEP we also noted an increase of alveolar dead space in Group 2. This study demonstrates the efficiency of high levels of PEEP to reduce QS/QT in ARF but also shows its limitations: namely reduction in cardiac performance and in efficiency if the damage to one lung is significantly more pronounced than that to the other lung.

Acute Disease↗
PubMed1981

Dobutamine: a hemodynamic evaluation in human septic shock.

The hemodynamic effect of dobutamine infusion (DI) was studied in 19 patients with septic shock. DI resulted in hemodynamic improvement as indicated by a significant increase in cardiac index (+36%, p less than 0.001), stroke index (+15%, p less than 0.01), mean arterial pressure (+20%, p less than 0.01), and a significant decrease in aVDO2 (-27%, p less than 0.01). This hemodynamic improvement occurred concomitantly with a fall in both right and left filling pressures. Mean systemic arterial resistance remained unchanged with a scatter of individual responses depending on other factors, such as infusion rate, initial vascular resistance, and underlying hemodynamic setting. In patients mechanically ventilated, venous admixture in the lung (Qs/Qt) during DI increased significantly (+30%, p less than 0.001) and insignificantly reduced PaO2, but this adverse effect was not observed when PEEP was used in patients mechanically ventilated. It is concluded that dobutamine can be useful in management of septic shock, particularly when filling pressures are high because of fluid overload or cardiac failure.

Adult↗
PubMed1981

[Cardiovascular effects of cigarette smoke in the rat. Aortic endothelial and myocardial capillary permeability in the rat].

The permeability of aortic endothelium and myocardial capillaries was examined in 72 Sprague-Dawley rats (approximately 350 g) using the diffusion tracer peroxidase. Animals were subjected to cigarette smoke for periods of 1 day (acute effects), 2 weeks (sub-acute effects) and 15 weeks (chronic effects) and were sacrificed 5 minutes or 8 hours after smoking. Peroxidase was not generally present at the sub-endothelial level in the aortic endothelium of control animals and sham-smokers. However, in smokers, the increase in peroxidase permeability is proportional to the smoking period. Moreover, in these smokers we observed junctional and subendothelial vacuolar dilatations which correspond to degenerative morphologic changes. Cigarette smoke has a different effect on the right ventricle. Endothelial permeability of the myocardial capillaries increases in animals subjected to cigarette smoke for 1 day and those who smoked for 2 weeks sacrificed 5 minutes after smoking. This increase in permeability is not related to the significant morphologic changes observed in the myocardium and endothelial capillaries. However, the myocardial endothelial capillaries, the sub-endothelial space and the adjacent interstitial space were generally free of peroxidase in animals subjected to cigarette smoke for 15 weeks and in those smoking for 2 weeks sacrificed 8 hours later. An adaptive phenomenon to the effects of cigarette smoke appear to exist in the myocardial endothelium capillaries contrary to that which is observed in the thoracic aorta.

Animals↗
PubMed1980

Effects of cigarette smoke on rat thoracic aorta.

Using the fine structural macromolecular tracer horseradish peroxidase (HRP) the permeability of thoracic aorta was studied in 72 male Sprague-Dawley rats. Rats smoked for 1 day (acute effect), 14 days (subacute effect) and 15 weeks (chronic effect). Thoracic aorta sections from control rats and sham smokers were free of HRP reaction product. In smokers' thoracic aortas, permeability to peroxidase increased proportionately to the increase in length of the smoking period. Furthermore, smokers' thoracic aortas exhibited focal vacuolar dilatations (subendothelial blebs) and an increased number of subendothelial macrophages.

Animals↗
PubMed1978

[Spectrofluorimetric estimation in biological fluids of a new beta-blockader: atenolol. Application to its pharmacokinetic study (author's transl)].

The authors describe a simple method of fluorimetric estimation of atenolol, applicable to blood and urine, sufficiently sensitive to permit a pharmacokinetic study. After administration of a dose of 200 mg by the oral route to hypertensive subjects, one may observe a maximal plasma concentration 3 hours after the dose average value 3.91 +/- 0.71 mumol/l (1.04 +/- 0.19 mg/l). The apparent half life of elimination of phase beta is 14.1 +/- 4.9 h, values comparable with those calculated from urinary data 14.6 +/- 2.0 h. The renal clearance was 140 +/- 32 ml/min; 54 +/- 14% of the administered dose are excreted in the urine. After administration by the venous route, urinary excretion represents 96% of the dose administered.

Adult↗
PubMed1978

[The value of the study of brain stem reflexes in coma (author's transl)].

A better clinical assessment of the comatose state is obtained by the study of brain stem reflexes. Systematic research of the fronto orbicular, pupillar, corneal, masseteric, vestibulo-ocular, oculo-cardiac, palmo-mental and cornéo mandibular reflexes has enabled characterization of functional levels. Degree of comatose stade and other usual physical symptoms have been correlated. Hence brain stem injury and course is followed in acute coma. Six functional levels permit assessment of cranio-caudal disintegration of brain stem functions. According to our opinion, diencéphalo-mesencephalic level is of bad prognosis in the course of follow-up.

Adolescent↗