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Biomedical subjects

J Bonnet

Publications and source records attributed to J Bonnet.

At least 235 records · Page 13Linked to original sources

Short- and long-term risk factors for sudden death in patients with stable angina.

Sudden death is most common and often the first manifestation of coronary heart disease although its risk is difficult to predict. It has been studied mainly in patients with severe ventricular arrhythmia or recent myocardial infarction, but little is known about the different risk factors for short- and long-term risk of sudden death in patients with stable angina. To assess risk factors for sudden death in patients with stable angina and angiographically proven coronary artery disease, 319 consecutive patients were recruited prospectively and followed-up. Patients with clinical heart failure or recent myocardial infarction were excluded. Clinical, angiographic and biological variables were recorded. The association between each variable and the risk of sudden death was assessed in univariate and logistic multivariate analysis. There were 25 sudden deaths during the follow-up period (97+/-29 months). The univariate predictors in the short-term (2 years) were: peripheral arterial disease, left ventricular hypertrophy, low density lipoprotein cholesterol and ejection fraction. The independent predictors were: peripheral arterial disease (relative risk: 6.3), ejection fraction (relative risk 1.05) and low density lipoprotein (relative risk: 1.8). In the long-term (8-10 years), body mass index, coronary score, ejection fraction and fibrinogen were univariate predictors. Only body mass index (relative risk: 1. 2), ejection fraction (relative risk: 1.06) and fibrinogen (relative risk: 2) remained independent predictors. The risk factors for sudden death in stable angina were time-dependent, peripheral arterial disease appeared as the best predictor with LDL for short time, and body mass index (obesity: index >27) and fibrinogen for long time. Ejection fraction was the only time-independent predictor.

Adult↗

[Technical evolution of irradiation in stereotactic conditions: dose fractionation].

The development of non-invasive head fixation systems, allowing 3D determination of the target coordinates, has lead to the increased use of fractionated stereotactic irradiation. These systems have been checked for accuracy and the mean precision of repositioning has been evaluated to +/- 1 mm. With the mean geometrical accuracy set at +/- 1 mm, a 2 mm safety margin is usually added to the clinical target volume in order to define the planning target volume. Quality assurance procedures must conform to the required precision of the technique while remaining realistic in day-to-day use relative to planned conventional treatments. Biologically different from single dose irradiation, the fractionated stereotactic irradiation completes the range of techniques used in the treatment of intra-cerebral lesions.

Dose Fractionation, Radiation↗

Phenotypic modification of arterial smooth muscle cells in response to medial dissection.

BACKGROUND: In the treatment of peripheral arteries, percutaneous transluminal angioplasty is commonly associated with intimal tears and dissections. OBJECTIVE: To investigate the influence of medial dissection on the remodelling of the vessel wall after balloon injury. METHODS: Aortae were obtained from 14 Fauve de Bourgogne rabbits that had been fed a normal diet. Seven days after the initial pull-back injury, the aortae were examined using morphometric and immunocytochemical methods. RESULTS: Eight rabbits (57%) had a tear that extended into the media. Morphometric measurements showed that the intima was significantly thinner when there was a medial dissection [(18.3 +/- 6.9) x 10(-3) versus (39.1 +/- 3.5) x 10(-3) mm without dissection, P < 0.001]. In the media of injured vessels, medial dissection was associated with a greater accumulation of extracellular matrix proteins (50.5 +/- 9.7 versus 12.4 +/- 2.2% of the surface area), a marked reduction in alpha-smooth muscle actin content (36.6 +/- 5.4 versus 47.4 +/- 7.5% of the surface area), a higher expression of a smooth muscle activation antigen (21.2 +/- 5.7 versus 8.9 +/- 1.5% of the 2P1A2-immunostained surface area) and an increase in the number of medial proliferating cell nuclear antigen-positive nuclei (8.2 versus 1.2% of labelled nuclei). CONCLUSION: These observations indicated that mechanical injury of the arterial wall induces a phenotypic activation of medial smooth muscle cells. In the case of acute distension, the response of the smooth muscle cells in the media was mainly responsible for wound healing in the presence of medial dissection; moreover, acute distension induced a significant higher state of activation and a medial repairing that could prevent migration towards the intimal space.

Actins↗

[Sub-adventitial rupture of the popliteal artery and recurrent ischemia: a diagnostic pitfall in young patients].

In the absence of thromboembolic risk factors, signs of thrombosis in situ, or disorders of coagulation, two possible diagnoses must be envisaged when acute recurring ischemia is observed in a peripheral area of tissue: extrinsic compression or rupture of an arterial coat, especially when the subject is young and in good general health. The case of a 35 year old patient presenting with recurring ischemia in the popliteal artery of the right lower limb due to sub-adventitial rupture of the popliteal artery suggests three comments: the period of latency (3 months) between initial trauma to the popliteal artery and the operation of reverse saphenous vein bypass, the necessity for dynamic manipulations together with angiographic and ultrasound examination, the probable underestimation of the traumatic or functional causes of this disorder (popliteal artery), and the surgical prognosis remains excellent.

Adult↗

cis-Dichlorodiamminepltinum(II) in adult patients: Southwest Oncology Group Studies.

In addition to cis-dichlorodiammineplatinum(II) studies in lymphomas and testicular cancer and a broader phase II study of all genitourinary malignancies, the Southwest Oncology Group is currently conducting eight other studies which examine the effectiveness of this drug in adult patients with a variety of tumor types. This report will give preliminary analyses of the five studies for which there are early data, plus briefly describe the design of the three remaining protocols for which there are no data as yet.

Adult↗