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Biomedical subjects

D Michel

Publications and source records attributed to D Michel.

At least 199 records · Page 11Linked to original sources
PubMed1985

[Benign acute cerebral angiopathy. 4 cases].

Presenting symptoms in 4 patients with acute benign cerebral angiopathy were headaches over several days, with a transient neurologic disorder in two cases. Angiography showed diffuse and segmental distal narrowing alternating with dilatations. In one patient, the radiologic anomalies persisted to a milder degree in the same region 2 months later, while the reduced cerebral blood flow failed to return to normal. The pathophysiology of this syndrome would appear to result initially of vasospasm in particularly reactive subjects, especially young women. Its cause appears to vary from one case to another: post-partum disorders, infection or inflammation, meningeal hemorrhage, paroxysmal hypertension. Adjuvant factors could be unusual effort, medication or a migraine context. In spite of this pathogenetic uncertainty this angiopathy in usually considered as an isolated, benign and non-relapsing disease.

Acute Disease↗
PubMed1984

Dexamethasone is a potent stimulator of growth hormone-releasing factor-induced cyclic AMP accumulation in the adenohypophysis.

The stimulatory effect of maximal concentrations of synthetic human pancreatic growth hormone (GH)-releasing factor (GRF)(1-40)NH on cyclic AMP accumulation in rat anterior pituitary cells in culture is 4.5-fold increased following a 48-h preincubation with the potent glucocorticoid dexamethasone while the sensitivity of GRF action is increased by approximately 4-fold. Dexamethasone pretreatment, on the other hand, has no effect on basal cyclic AMP levels but approximately doubles both basal and GRF-induced GH release. The present data suggest that the potent stimulatory effect of glucocorticoids on GH secretion is exerted on the adenylate cyclase system at a step preceding cyclic AMP formation.

Animals↗
PubMed1983

[Iatrogenic hypotension in the aged].

Hypotensive states reach a definite implication in old age, if they present themselves as orthostatic dysfunction or as focal hypotension as a result of vascular stenoses. Interactions of diseases (multimorbidity) with age-related dysfunctions of homeostasis and circulation and with cardio- and vasoactive drugs may become a considerable danger for the old patient; e.g. persistent organic lesions. Drug-induced hypotension in old age may lead to severe emergency situations. In view of the great number of drugs with desired lowering of blood pressure or hypotensive side effects used for therapy of old patients an accurate indication is imperative.

Aged↗
PubMed1983

Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients.

Verbal humor deficits were investigated in right-hemisphere-damaged patients. It was hypothesized that the appreciation of jokes presupposes two elements: sensitivity to the surprise element entailed in the punch line of a joke and apprehension of the coherence which results when the punch line has been integrated with the body of the joke. The possible dissociation between these elements was tested by asking subjects to select from four alternatives the appropriate ending to a joke. Right-hemisphere patients exhibited a selective attraction to endings which contained an element of surprise but which were not otherwise coherent with the body of the joke. This finding suggests that right-hemisphere patients have difficulty in integrating content across parts of a narrative and confirms the psychological reality of the proposed distinction between the surprise and coherence elements of humor processing.

Adult↗
PubMed1983

Interactions between growth hormone-releasing factor, prostaglandin E2 and somatostatin on cyclic AMP accumulation in rat adenohypophysial cells in culture.

Synthetic human pancreatic growth hormone-releasing factor (hpGRF(1-40)-NH2) causes a 100% stimulation of cyclic AMP cell content in rat adenohypophysial cells in culture as early as 1 min after its addition while a maximal 33-fold increase is measured at 40 min. Somatostatin (10 nM) causes a 40-60% inhibition of GRF-induced cyclic AMP accumulation while GH release is inhibited by 90-95% at all time intervals. The inhibitory effect of somatostatin is exerted on the maximal effect of GRF while the ED50 values of GRF action on cyclic AMP cell content (approximately 1 nM) and GH release (approximately 0.1 nM) are not affected by the tetradecapeptide. Prostaglandin E2 causes a 2.5-fold increase in cyclic AMP levels within 1 min after its addition with a maximal 25-fold stimulation measured at 30 min. Although not completely additive, the stimulatory effects of PGE2 and GRF together on cyclic AMP cell content and GH release are more potent than when either substance is present alone. The inhibitory effects of somatostatin on PGE2 action are analogous to those observed in the presence of GRF. The present data suggest that the hypothalamic control of GH secretion by GRF and somatostatin results, at least to a large extent, from the balance between the stimulatory action of GRF and the inhibition of somatostatin on the adenylate cyclase system.

Animals↗
PubMed1983

Immunocytochemical demonstration of Con A-receptors on the cell surface of guinea pig peritoneal macrophages.

By means of protein A-gold in combination with the replica technique the distribution of Con A-receptors on the surface of guinea pig peritoneal macrophages was investigated. In nonspecifically activated macrophages the arrangement of Con A-binding sites was demonstrated as homogeneous. It could be evidenced that by the combined technique the advantages of the high resolution of transmission electron microscopy could be joined with the possibility of the stereological demonstration of cell surface structures.

Animals↗
PubMed1983

[Biological, psychometric and tomodensitometric study of treated neurosyphilis].

Results of follow-up examinations of the CSF in 6 patients with neurosyphilis, including 5 with general paresis, following treatment with high doses of aqueous penicillin G are reported. Persistence of any residual active infection of the nervous system could be eliminated since as well as fairly rapid restoration of normal CSF cytology and chemistry there was a slow reduction (and sometimes return to normal) of initially very high levels of immunoglobulins G, disappearance of their oligoclonal distribution (3 cases), and negativation of quantitative immunofluorescence serology (F.T.A. ABS). Clinical efficacy of treatment was shown by stabilization of the intellectual deficit investigated by serial psychometric tests. Memory disturbances were prominent mainly in the initial stages, and sometimes adopted a rather frontal nature. Psychometric tests can contribute to the assessment of initial extension of the treponemic infection in the aborted types of general paresis. The atrophy observed constantly on CT scans appeared to be stationary on serial examinations (2 cases). It was of a diffuse type affecting cortical sulci and ventricles. The onset of anomalies such as ischemic complications was not related to recurrence of infection.

Adult↗
PubMed1983

[Intramedullary bronchogenic cyst. Apropos of 1 case. Discussion of the endo-ectodermal adhesion syndrome].

The authors report the case of a 40-year-old man who has presented for many years an intermittent progressive spastic paraplegia. Plain films of the spine show very important dysraphic abnormalities of the inferior dorsal column and the myelography shows a complete block suggesting an intramedullary space-occupying lesion at four levels above the vertebral abnormalities. The operation permits a total removal of an intramedullary "bronchogenic cyst". In the post-operative course, the neurologic deficit improves, six months later a spastic paraparesia remains. The review of the literature shows that this is an exceptional observation. Intramedullary bronchogenic cysts must be regarded as similar to intramedullary enterogenic cysts. They are not teratomas but dysembryoplasiae due to failure of the ento-ectoblastic separation between the second and the third weeks of life. These cysts form a part of the "ento-ectodermal adhesion syndrome" of Prob et al. The preoperative diagnosis is possible on the association of intermittent progressive syndrome of medullary compression and dysraphic spondylotic changes. The total surgical removal of the cyst, by micro-surgical techniques, is able to preserve the neurologic evolution with an excellent result if the operation is performed before definitive neurologic deficits occur.

Adult↗
PubMed1982

[Secondary prevention after myocardial infarction in the aged (author's transl)].

Mortality during the first six to eight months after acute myocardial infarction is primarily due to sudden cardiac death and myocardial reinfarction. Therefore any secondary preventive measures have to be aimed at these complications of coronary heart disease and should be effective during the first six months after myocardial infarction. Results of comprehensive studies permit the following conclusions: application of beta-blocking agents may result in a significant reduction of total mortality, sudden cardiac death and the incidence of reinfarction in the old patient. They should be used as the regimen of first choice in a general routine prevention after myocardial infarction. In special cases coronary artery surgery provides an additional means for effective prevention. Compared to this platelet aggregation inhibitors, modification (resp. treatment) of risk factors and physical methods are of minor importance for secondary prevention after myocardial infarction in old patients.

Adrenergic beta-Antagonists↗