A 4He vector zero-field optically pumped magnetometer operated in the Earth-field.

Low intrinsic noise, high bandwidth, and high accuracy vector magnetometers are key components for many ground or space geophysical applications. Here, we report the design and the test of a 4He vector optically pumped magnetometer specifically dedicated to these needs. It is based on a parametric resonance magnetometer architecture operated in the Earth magnetic field with closed-loop compensation of the three components of the magnetic field. It provides offset-free vector measurements in a ±70 µT range with a DC to 1 kHz bandwidth. We demonstrate a vector sensitivity up to 130 fT/√Hz, which is about ten times better than the best available fluxgate magnetometers currently available for the same targeted applications.

Plasma lipid fatty acids and platelet function during continuous subcutaneous insulin infusion in type I diabetes.

Eleven insulin-dependent diabetics exhibiting a fair but less than ideal diabetic control (HbA1 = 10.0 +/- 0.6%) were submitted in a random order to two 6 week-study periods of: continuous subcutaneous insulin infusion (CSII) and optimized conventional insulin therapy. Plasma lipids, fatty acids in plasma lipids and platelet function were estimated at baseline and at the end of each study period. Declines in HbA1 were observed at the end of either CSII or conventional period compared with baseline, but the differences were only significant under CSII (P less than 0.02). Plasma lipids and apoproteins remained unchanged at the end of the two study periods compared with baseline. Both CSII and optimized conventional treatment were followed by a significant increase of arachidonate in plasma lipids. A deterioration of the platelet function estimated from ADP or epinephrine-induced platelet aggregation and TxB2 generation by platelets was found under optimized conventional treatment while the platelet function appears to be normal at baseline and under CSII. These data indicate that slight but not sufficient improvements of diabetic control can result in deterioration of the platelet function. It seems that these deleterious effects are mediated through an increased production of arachidonate and in turn of TxB2.

[Traumatic myocardial infarct]. / L'infarctus du myocarde traumatique.

Two cases of traumatic, closed chest, myocardial infarction in two young patients, aged 18 and 19 years respectively, are reported. They illustrate the two possible physiopathological mechanisms of this affection: in the first case, myocardial contusion after thoraco-abdominal trauma by crushing, probably complicated by a subendocardial tear of the inferior wall of the left ventricle, with a spontaneous favourable outcome; in the second case, a transmural myocardial infarction was observed secondary to a coronary lesion (? tearing of the adventitia of the left anterior descending artery) complicated by the early development of a large antero-apical aneurysm. Haemodynamic and arrhythmic complications necessitated infarctectomy and aorto coronary bypass surgery on the 35th day. The pathological lesions and their outcome are examined with respect to these two cases. The diagnostic, therapeutic and medieolegal problems associated with this condition are also discussed.

[Systemic arterial spasms. Ergotamine tartrate]. / Spasmes artériels systémiques. Tartrate d'ergotamine.

The problem of the toxic effects of ergotism is raised by two cases of acute lower limb ischaemia observed in young patients. Although commonly encountered up to the 20th century, the problem is now reappearing sporadically from iatrogenic causes. The clinical features and treatment of ergotism are discussed. Prophylaxis is based on two main principles: the respect of contraindications, the most important being hypertension, coronary insufficiency, arteriopathies, acrocyanosis and thrombophlebitis, and less importantly, the association of tetracycline type antimicrobials, triacetyloleandomycin and phenothiazine; on the other hand, attention must also be paid to the instructions on its use, particularly with respect to the maximum dosage, 4 mg/day per os, 10 mg/week per os. The treatment should be given intermittently and not continuously. Full knowledge of the composition of composite drugs is required as many drugs are commercialised with their ergotamine content masked. This justifies, if there is still need, constant pharmacovigilance.

[Myocardial infarct in 2 stages]. / L'infarctus du myocarde en 2 temps

The two-step myocardial infarction is defined by a peculiar course: the initial stage is a temporary rudimentary infarction, the late stage a typical transmural necrosis, separated by a free interval of a variable duration. A coronary arteriography undertaken when the recurrence starts might eventually lead to recommend an emergency operation: two-step myocardial infarction might represent one of the best indications for emergency aorta-to-coronary artyery by-pass operation.