La semaine des hopitaux : organe fonde par l'Association d'enseignement medical des hopitaux de Paris最新文献

Polypeptides are endogenous agents, involved in the regulation of many physiologic functions and the pathogenesis of several diseases. Polypeptide antagonists form a group of new chemical entities which may provide valid therapeutic agents. Some polypeptides (angiotensin, kinins) are released through the action of proteolytic enzymes (renin, kallikreins) and act as hormones or autacoids; others (substance P, neurotensin) are synthetized by nervous cells to serve as neurotransmitters or neuromodulators. The main homeostatic role of the renin-angiotensin system is to uphold high systemic arterial blood pressure. Overproduction of renin and insufficient checking of renin secretion are among the most common causes of arterial hypertension. Several forms of arterial hypertension (neurovascular, idiopathic) benefit from a reduction in renin-angiotensin system activity. This is achieved either through decreasing renin secretion, by inhibiting conversion of angiotensin I into angiotensin II, or through blocking the peripheral actions (at the receptor sites) of angiotensin II. Renin secretion is very significantly reduced by beta-blocking agents (propranolol); conversion of angiotensin I into angiotensin II is inhibited by teprotide, captopril and their derivatives; peripheral actions of angiotensin II are blocked by saralasin. Bradykinin and related agents produce vasodilation, increase vascular permeability and stimulate pain fibers. Kinins thus reproduce the cardinal features of inflammation and are held to be mediators of the inflammatory reaction. The substance P neuropeptide is found in the brain and bowel; it may act as a transmitter of the sensation of pain at the spinal cord and central nervous system sites. Among other effects outside of the brain, substance P is a potent vasodilator and inhibits renin secretion. Neurotensin is a neuropeptide which produces hypothermia, muscular relaxation and analgesia. Outside of the brain, this peptide is involved in the regulation of gastric secretion, intestinal motility and insulin and glucagon secretion. The vasoactive intestinal peptide, found in certain cholinergic nerve endings, is a large peptide which inhibits gastric secretion, intestinal motility and vascular tone.

Castleman tumor usually presents as a mediastinal tumor which is never accurately diagnosed before surgery. Pathological findings and postoperative course establish the benign nature of this tumor. However, plasmocytic forms with prominent hematologic manifestations may be difficult to distinguish from a malignant lymphoma or thymoma. Differential diagnosis is all the more important that no complementary postoperative treatment is indicated in benign lymphoid tumors.

Forty patients with stage III or IV ovarian epithelial carcinoma, mean age 61 +/- 12 years, were treated either with cyclophosphamide-methotrexate-5-FU or with cisplatinum-adriamycin-5-FU-hexamethylmelamine. Median survival from initial surgery was 16 months, 18 months in stage III and 2 months in stage IV disease. 15 patients over 70 years had a median survival of 9 months. Median survival was higher with the regimen without cisplatinum (18 months against 13 months). Clinical response rate was 62.5%. Ten patients clinically free of disease underwent second look laparotomy which showed persistent disease in six. Based on these results and on a review of the literature, a new therapeutical approach is discussed.

Leukotrienes are released in inflammatory and immediate hypersensitivity reactions. Leukotrienes are novel metabolites of arachidonic acid produced by the lungs and leucocytes. Their formation is catalyzed by a specific 5-lipoxygenase. The key compound of this pathway is leukotriene A4 which is transformed either into leukotriene B4 by enzymatic hydrolysis or into leukotriene C4 by addition of glutathione. Leukotriene D4 and E4, as well as their precursor leukotriene C4, are the myotropic constituents of the "Slow Reacting Substance of Anaphylaxis" (SRS-A). Leukotrienes are potent bronchoconstrictors in vitro and in vivo. They induce the production of mucus by the respiratory tract and decrease its transport. Leukotrienes (chiefly leukotrienes C4, D4 and E4) induce the vasoconstriction of large vessels and capillaries. Leukotriene B4 stimulates several leukocyte functions related to inflammation (chemotaxis, aggregation, release of lysosomal enzymes and production of superoxide anion). In addition, it induces the formation of suppressive and cytotoxic T-Lymphocytes. The actions of leukotrienes are mediated by specific receptors and, in certain organs, their mechanism of action involves a stimulation of the formation of prostaglandins and thromboxanes. Non-steroidal antiinflammatory drugs (aspirin) inhibit the biosynthesis of prostaglandins and thromboxanes, whereas steroidal antiinflammatory agents (dexamethasone) should inhibit the production of leukotrienes as well as of prostaglandins and thromboxanes (through an indirect action on phospholipase A2).

A new observation of chronic X-linked recessive spinal amyotrophy is reported. This series of cases fits the description of Kennedy-Stefanis chronic spinal amyotrophy, whose main characteristics are: sex-linked recessive inheritance, weakness and bulbo-spinal amyotrophy with proximal predominance, facio-lingual fasciculations, areflexia, gynecomastia in half of cases, very slowly progressive course, neurogenic EMG with normal nerve conduction velocities, and neurogenic muscle biopsy.

An observation of adrenergic myocarditis with clinical and electrical signs of coronary failure is reported. The patient had electrical and enzymatic manifestations of acute anteroseptal necrosis, complicated at the acute stage by complete atrioventricular block and fatal vasoplegic circulatory collapse. Post-mortem examination showed obstructive atherosclerosis of the anterior interventricular artery without anatomic signs of infarction. Pathogenesis of this coronary failure is discussed. In this case, functional coronary insufficiency produced by catecholamine release was associated with coronary atherosclerosis.

Disturbances in the kynurenine pathway are present in pellagra and pellagroid syndromes. In 88 photodermatoses, the authors found increased urinary excretion of xanthurenic acid after oral load of tryptophan in a number of light-induced eruptions, i.e. benign summer photodermatosis (40%), polymorphous light eruptions (37%), and persistent light reactions (36%) as well as in patients with acute alcoholic intoxication. These biochemical abnormalities in the kynurenine pathway allow for a pathogenetic approach in some photodermatoses.

Changes in mean corpuscular volume (MCV) were studied in cancer patients. Vitamin B12 or erythrocyte folate deficiencies were observed in only 9% of macrocytic patients (MCV greater than or equal to 100 fl). Bone marrow study in seven macrocytic patients with normal hemograms and normal levels of vitamin B12 and folic acid, on per os daily cyclophosphamide single agent therapy, showed myelodysplastic features. The highest MCV and MCV increases during therapy among 203 patients were observed in those cancers and cytotoxic therapies most commonly followed by secondary leukemia: Hodgkin's disease treated with MOPP and radiotherapy, and multiple myeloma and ovarian cancer treated with Melphalan. 21 patients who developed secondary leukemia had a higher MCV and a greater MCV increment than the control patients. Differences were significant in Hodgkin's disease. This preliminary report strongly supports monitoring MCV changes during cytotoxic therapy to attempt identification of patients at high risk of secondary leukemia.

Patients with severe somatic disorders producing a wide spectrum of manifestations which are often irreversible are managed by psychoanalysts specialized in psychosomatics in a unique care center, the Poterne des Peupliers Hospital in Paris. Current results--with a five year follow up--show that such care programs are well-founded as concerns both economic costs and validation of the theory on which they are based. Indeed, it appears that, whatever the somatic disease, mental support improves regulation of the patient's general psychosomatic economy, thereby achieving abatement or resolution of somatic manifestations.

The authors' purpose was to confirm their hypotheses based on their prior study of the effect of tiapride and lorazepam on memorizing capacities of patients over sixty years of age. The results of a two weeks, double-blind trial show that tiapride, in addition to its sedative action, produces disinhibition and enhances wakefulness, thereby improving memory performances in the elderly.