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Biomedical subjects

J Bonnet

Publications and source records attributed to J Bonnet.

At least 181 records · Page 10Linked to original sources
PubMed1984

Global left ventricular function and regional wall motion in pure mitral stenosis.

Global left ventricular function (LVF) and segmental wall motion of the left ventricle are registered in 113 patients presenting a pure mitral stenosis (MS) and in a control group of 50 individuals. The segmental wall motion is measured on the end-diastolic-end-systolic frames of the left ventricle, obtained from right anterior oblique (RAO) monoplane cineangiography. Measurement of the segmental wall shortening is performed using the Stanford method. Group 1 includes 68 patients (60% of the total number of patients studied). These patients show no pathological contraction abnormality. In this group, the global LVF is not different from the control group. Group 2 includes 45 patients (40% of the total) for whom contraction abnormalities are present: anterior hypokinesis in 20% of the cases (anterior area mean shortening (AAS) = 18 +/- 8%; p less than 0.001 vs. group 1 and control group), and posterior hypokinesis in 20% of the cases (posterior area mean shortening (PAS) = 9.8 +/- 5.8%, p less than 0.001 vs. group 1 and control group). In this group, global LVF is impaired; ejection fraction (EF) = 0.57 +/- 0.1% (p less than 0.001 vs. group 1); velocity of circumferential fiber shortening (VCF) = 1 +/- 0.3 circ/s (p less than 0.001 vs. group 1); enddiastolic pressure (EDP) = 11 +/- 5 mmHg (p less than 0.01 vs. group 1). Segmental contraction abnormalities appear to be the main factor involved in the global LVF impairment. Segmental wall motion abnormalities could be related to subvalvular fibrosis, or LV filling difficulties, or principally, to a possible interplay between the right and the left ventricles.

Adult↗
PubMed1984

[Left ventricular global and segmental function in pure mitral valve prolapse with poor tolerance for exertion].

Poor effort tolerance is observed in a small percentage of cases of idiopathic mitral valve prolapse (IMVP). The aim of this study was to assess the possible left ventricular dysfunction in such cases, responsible for poor effort tolerance. Left ventricular function and segmental wall motion were studied retrospectively in a group of 17 patients with IMVP. The patients, average age 53 +/- 12 years, had poor effort tolerance (ST segment depression of 2 to 4 mm in 15 cases, drop in blood pressure in 6 cases) justifying catheter and angiographic studies. All patients had IMVP confirmed on RAO left ventriculography. There was no associated mitral regurgitation or coronary artery disease. Left ventricular function was studied by parameters of global function (systolic and diastolic parameters, volume measurements) and by a quantitative study of segmental wall contraction. The method used for studying regional wall motion was an application of the Stanford method in which segmental shortening is studied over all the endocavitary contour of the LV during an angiographic cycle filmed at 50 frames/second in the RAO projection. The time and velocity amplitudes of wall motion were measured during systole and diastole. The same methodology was applied to 21 normal control subjects. The results showed abnormal volumic compliance and wall motion in the IMVP group. Asynergy was mainly confined to the antero-lateral wall of the LV. The amplitude of contraction was generally normal but the contraction was slower and finished earlier. In the same zone, relaxation was abnormally early and lasted longer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Efficacy and value of fibrinolytic agents in chronic proximal venous thrombosis of the lower limbs].

Forty patients (mean age = 56 +/- 17 years) hospitalized for proximal venous thrombosis of the lower limbs of over 7 days duration were treated with fibrinolytic drugs: streptokinase (SK) 28 cases, urokinase (UK) 12 cases. The efficacy of fibrinolytic therapy was assessed by phlebography before and 4.5 +/- 2 days after onset of treatment. A phlebographic score based on Marder's method was used to quantify the thrombosis. The repermeabilisation of venous branches was also noted. The results show an overall efficacy of fibrinolytic drugs: total lysis was observed in 6 patients and partial thrombolysis in 18 patients. The overall reduction of the phlebographic score was -2.8 +/- 3.9, and the rate of repermeabilisation of the femoral veins was over 50%. Streptokinase seemed to be the most effective drug. Better results were obtained when the thrombosis was treated early and was proximally situated, but good results were also observed in cases of total thrombosis with a floating thrombus. Effective fibrinolysis was observed in thromboses of up to 3 months duration. There was no correlation between biological efficacy and clinical symptoms. In conclusion, fibrinolytic drugs are partially effective in semi-recent or chronic venous thrombosis and their usefulness should not be overlooked, especially in cases of persistent thrombosis of the femoral veins.

Adult↗
PubMed1984

PAF-acether-induced plasma exudation in rat skin is independent of platelets and neutrophils.

The ability of Paf-acether to induce increased plasma protein extravasation (IPPE) was assessed in the skin of rats by measuring extravasation of 125I-bovine serum albumin. Paf-acether elicited dose-dependent IPPE with a threshold of 0.04 pmol and a maximum at 4.5 nmol, with an effective concentration (EC50) of 23 pmol. The EC50 of the 1-0-ester Paf-acether analog was 1.5 nmol whereas 2-lyso Paf-acether was ineffective in inducing IPPE. Serotonin and histamine were respectively 100 and 1,00-fold less potent than Paf-acether. High doses of Paf-acether also resulted in a dose related accumulation of III-indium oxine labeled platelets. Ultrastructural and radioisotopic studies showed that Paf-acether-induced IPPE was not dependent upon platelet accumulation. In addition, platelet release products were ruled out in this phenomenon, since a "cocktail" of indomethacin, methysergide and pyrilamine-maleate failed to significantly reduce Paf-acether-induced IPPE. Neutrophils were not involved in Paf-acether -induced IPPE since nitrogen mustard-treated animals presented with IPPE not significantly different from controls. Finally, the specificity of Paf-acether on IPPE formation was demonstrated by its complete prevention by prior intravenous injection of Paf-acether (6 ug/kg), but not of Paf-acether analogs, histamine or serotonin.

Animals↗
PubMed1983

Enrichment and characterization of the mRNAs of four aminoacyl-tRNA synthetases from yeast.

We have partially purified the messenger RNAs for yeast arginyl-, aspartyl-, valyl-, alpha and beta subunits of phenylalanyl-tRNA synthetases in order to study their biosynthesis and ultimately, to isolate their genes. Sucrose gradient fractionation of poly U-Sepharose selected mRNAs resulted in a ten fold enrichment of the in vitro translation activity of these mRNAs. The translation products of messenger RNAs for arginyl- and valyl-tRNA synthetases have the same molecular weight as the purified enzymes; translation of aspartyl-tRNA synthetase messenger RNA yielded a 68 kD molecular weight polypeptide (while the purified cristallisable enzyme appears as a 64-66 kD doublet, which, as we showed is a proteolysis product). The translation of the mRNAs for alpha and beta phenylalanyl-tRNA synthetase gave polypeptides having the same molecular weight as those obtained from the purified enzyme, but the major translation products are slightly heavier, indicating that they may be translated as precursors. As estimated from centrifugation experiments mRNAs of arginyl-, aspartyl-, alpha and beta subunits of phenylalanyl-tRNA synthetase were 1700-2000 nucleotides long, indicating that alpha and beta are translated from two different mRNAs.

Amino Acyl-tRNA Synthetases↗
PubMed1983

Acute circulatory collapse caused by platelet-activating factor (PAF-acether) in dogs.

Synthetic platelet-activating factor (PAF-acether) was shown to act as a shock inducer when a dose of 9 or 36 nmol . kg-1 was injected i.v. into dogs anesthetized with 30 mg . kg-1 i.v. sodium pentobarbitone. Nine nmol . kg-1 PAF-acether caused portal vein and pulmonary artery hypertension but only transiently; blood TXB2 and 6 keto PGF1 alpha levels rose; there was a lasting fall of 77% in systemic blood pressure, cardiac output fell by 86%, heart rate by 17%, plasma volume by 43%, and femoral artery blood flow by 66%, whereas the hematocrit rose by 33%. A dose of 36 nmol . kg-1 PAF-acether reduced coronary artery blood flow by 56%, diminished myocardial O2 consumption, raised O2 extraction and caused metabolic acidosis leading to death in 2 out of 7 animals. All these changes displayed the typical features of common acute circulatory collapse with distributive and hypovolemic etiologies, suggesting that PAF-acether might be an endogenous mediator in the early and late stages of shock.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Dependency of the Paf-acether induced bronchospasm on the lipoxygenase pathway in the guinea-pig.

The Paf-acether (platelet-activating factor) induced bronchospasm (Paf-BCS) was studied in the anesthetized guinea-pig. The SRS antagonist, FPL-55712, as well as inhibitors of both lipoxygenase and cyclooxygenase, phenidone, nordihydroguaiaretic acid (NDGA), and benoxaprofen, caused a dose-related antagonism of Paf-BCS. By contrast, selective inhibitors of cyclooxygenase, indomethacin and aspirin, exerted moderate antagonism at intermediate doses, but had no effect at high doses. Furthermore, diethylmaleate (DEM), which impairs leukotriene synthesis by interfering with glutathione (GSH), suppressed Paf-BCS. Taken together, these results demonstrate that the lipoxygenase pathway plays a major part in the bronchospasmogenic effect of Paf-acether in the guinea-pig.

Animals↗
PubMed1983

Primary structure of the Saccharomyces cerevisiae gene for methionyl-tRNA synthetase.

The sequence of a 5-kilobase DNA insert containing the structural gene for yeast cytoplasmic methionyl-tRNA synthetase has been determined and a unique open reading frame of 2,253 nucleotides encoding a polypeptide chain of 751 amino acids (Mr, 85,500) has been characterized. The data obtained on the purified enzyme (subunit size, amino acid composition, and COOH-terminal sequence) are consistent with the gene structure. The protein sequence deduced from the nucleotide sequence reveals no obvious internal repeats. This protein sequence shows a high degree of homology with that of Escherichia coli methionyl-tRNA synthetase within a region that forms the putative methionyl adenylate binding site. This strongly suggests that both proteins derive from a common ancestor.

Amino Acid Sequence↗
PubMed1983

[Functional content of the electrocardiogram of coronary patients].

A comparison of the haemodynamic and electrocardiographic data was carried out in 180 coronary patients. All underwent catheterisation and coronary angiography for angina. They were divided into three main groups: 53 patients with coronary atheroma without significant stenosis; 43 patients with at least one coronary stenosis greater than 50%; 84 patients had myocardial infarction with ECG changes of transmural necrosis and coronary thrombosis (or greater than 80% stenosis). Parameters of left ventricular function (LVF), especially ejection fraction (EF), systolic work (LVESW), end diastolic pressure (LVEDP), end diastolic volume (LVEDV), myocardial mass calculated from angiography (LMV) and volumic compliance were analysed in all cases. Each patient had at least 5 ECG recordings analysed by a HP 6 calculator which determined the values of the principal numeric ECG parameters and the means of the 5 recordings. Particular attention was given to the sum of the R waves in the 12 leads (sigma R mV) and Macruz's index (duration of P/PR - P in Lead II). A satisfactory correlation was found overall between sigma R and EF (r = 0,45, p less than 0,001). sigma R was the only ECG variable related to LVF in patients without infarction. In this group of 96 patients, sigma R correlated with LVEDV (r = 0,46, p less than 0,001) with LVM (r = 0,46, p less than 0,001), with LVESW (r = 0,52, p less than 0,001). There was a discordance between angiographically measured LVM and the mass of electrically active myocardium in patients with infarction. sigma R was independent of LVM, LVEDV, and LVESW.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗
PubMed1983

[Detection of coronary atherosclerosis before 45 or 50 years of age. Value of skin biopsy].

A three year prospective study was undertaken to determine the possible relationship of coronary atherosclerosis in subjects under 50 years of age, confirmed by coronary angiography, and structural changes of the connective tissue dystrophy. The independence of the histological changes with respect to other cardiovascular risk factors was also evaluated. The study was carried out by a double blind technique between the histological and clinical results. We present our preliminary results in 88 male patients, 64 with atherosclerosis and 24 controls. Histological abnormalities were found in 81.25% of patients with atherosclerosis compared to 33.3% in the control subjects. Accelerated skin aging, a simple diagnosis, requires only light microscopy for diagnosis and seems to be the simplest and most reliable screening test. It is found in 61% of atherosclerotic patients in the general population and in 74% of coronary patients under 45 years of age, independently of other risk factors especially cigarette smoking. As a screening test for coronary atherosclerosis before 45 years of age, the sensitivity was found to be 74.2% and specificity 57.1%, the predictive value being 79.3%. Connective tissue dystrophy needs electronic microscopy and seems to be less reliable in the detection of atherosclerosis as this condition is usually found in patients over 45 years of age. However, these changes are related to atherosclerosis and not to age. This study shows that skin biopsy in the search of accelerated skin aging, enables atherosclerosis to be detected simply and reliably, independently of other risk factors. This test, by defining the individual structural risk, is a method of following the progression or regression of atherosclerosis and so help control treatment.

Adult↗
PubMed1982

Combination chemotherapy, radiotherapy, and BCG immunotherapy in limited small-cell carcinoma of the lung: a Southwest Oncology Group Study.

From November 1976 to March 1979 the Southwest Oncology Group treated 298 patients with limited (disease confined to the chest and encompassed by one radiotherapy port) small-cell carcinoma of the lung with combination chemotherapy and radiotherapy with or without BCG immunotherapy. Two induction chemotherapy programs were utilized: (1) cyclophosphamide, vincristine, methotrexate, fluorouracil; or (2) cyclophosphamide, doxorubicin, and vincristine. Patients received 4500 rads of radiation therapy to the bulk primary tumor and 3000 rads to whole brain followed by maintenance chemotherapy. One-half of all the patients were randomized to receive one vial (5 x 10(8)) of high viability Pasteur BCG by scarification technique given on days 8 and 15 of each 21--28 day treatment cycle. Increased granulocytopenia accompanied the addition of BCG immunotherapy. Patients receiving BCG achieved a response rate of 49% vs. those patients not receiving BCG of 44% (P = 0.579). Median response duration was 40 weeks for the BCG arms and 38 weeks for the arms without BCG; survival was no different, 42 weeks for the BCG arms vs. 50 weeks for the arms without BCG. In patients who responded to therapy and survived longer than one year, those who continued to receive BCG therapy demonstrated a slight, yet significant, survival benefit over those patients not receiving BCG (93 weeks vs. 81 weeks, P = 0.03). It appears that BCG immunotherapy has no beneficial effect on response rate, duration of response, or survival in programs using chemotherapy and radiotherapy for control of limited small-cell carcinoma of the lung except in this small group of long-term survivors.

Antineoplastic Agents↗
PubMed1982

An epiiluminator/detector unit permitting arc lamp illumination for fluorescence activated cell sorters.

The application of arc lamps to flow cytometers is discussed and epiillumination for jet-in-air cell sorters is introduced. An epiilluminator/detector unit equipped with a mercury arc lamp constructed for a commercially available cell sorter is described. Experiments in which laser and mercury arc lamp illumination were compared show that the signal-to-noise ratio for the arc lamp illumination is predominantly limited by shot noise from constant light backgrounds due to reflected excitation light and ambient light. Arc lamp illumination can be used for the sorting of highly fluorescent objects such as cells stained for DNA by for example: ethidium bromide, propidium iodide, or the Hoechst dyes. The simultaneous employment of mercury arc and laser light sources as an inexpensive dual wavelength system is discussed.

Cell Separation↗
PubMed1982

Vincristine, BCNU, doxorubicin, and prednisone (VBAP) combination in the treatment of relapsing or resistant multiple myeloma: a Southwest Oncology Group study.

A total of 151 patients with myeloma who had relapsed with or were resistant to melphalan and/or cyclophosphamide (Cytoxan) with prednisone received vincristine, carmustine (BCNU), doxorubicin (Adriamycin), and prednisone (VBAP) at 21-day intervals; 39 patients (25%) responded. Of the 123 patients with relapsing myeloma, 37 (30%) responded. Only two (7%) of the 28 patients with resistant myeloma responded. The regimen was well-tolerated in patients who had not had prior extensive irradiation. Thrombocytopenia was the most frequent form of toxicity. Survival was significantly longer in those patients responding to VBAP (median, 78 weeks) than in those not responding (median, 33 weeks) (P = 0.002). VBAP is a safe, effective regimen for patients with myeloma who relapse with alkylating agents.

Antineoplastic Agents↗