Biomedical subjects
M Klein
Publications and source records attributed to M Klein.
Influence of valve surgery on female fertility.
Pregnancies following cardiac valve surgery represent a considerable maternal and fetal risk. The present paper is a report of 163 women in child-bearing age who underwent cardiac valve surgery. Congenital (14.7%) and acquired (85.3%) cardiac defects required a total of 72 alloplastic and 16 bioprosthetic valve implantations. In 69 patients, purely instrumental correction was performed, in 6 patients conduits were placed. Thirty-four pregnancies were observed and led to the delivery of 18 healthy infants. The birth weight was always in the 2-sigma normal range or slightly above. Three cesarean sections were performed due to the cardiac defect, in 6 patients vacuum extraction or forceps delivery was done, and in 9 patients delivery was spontaneous. We observed 4 cases of spontaneous abortion, and in 12 cases interruption of pregnancy. 75.1% women never became pregnant. Potential risks in terms of endocarditis, repeated valve implantation and anticoagulation are emphasized, methods to decrease the physical strain during delivery are discussed.
Energetic metabolism in hypothyroid skeletal muscle, as studied by phosphorus magnetic resonance spectroscopy.
Phosphorus nuclear magnetic resonance spectroscopy was used to investigate the muscle bioenergetics in different hypothyroid states. Using the thenar muscle group as reference, 2 patients with chronic and severe hormonal deficiency, 3 patients with subacute hypothyroidism, and 8 patients with moderate thyroid insufficiency with isolated high blood TSH levels were studied at rest, during exercise, and during subsequent recovery. The patients were compared with 15 control subjects. Only 1 patient presented a clinical myopathy. The intracellular pH and the relative measurements of inorganic phosphate, phosphocreatine, phosphodiesters, and ATP were directly calculated from phosphorus spectra. Resting muscle showed a significant rise in the inorganic phosphate to ATP ratio. In working hypothyroid muscle, a more important decrease in phosphocreatine levels was noted in patients with chronic and subacute thyroid deficiency, while the intracellular pH fall was greater in all hypothyroid patients than in control subjects. The phosphocreatine recovery rate was lower in all deficient patients, reflecting a probable mitochondrial metabolism impairment. These results are consistent with a defect of the high energy phosphate metabolism in hypothyroidism, even in moderate or recent hormonal deficiency.
Avascular necrosis of bone mimicking symmetric polyarthritis in a patient with malignant lymphoma treated with high-dose steroids.
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Shiftwork strategies: retaining night nurses.
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High-affinity dextromethorphan and (+)-3-(-3-hydroxyphenyl)-N-(1-propyl)piperidine binding sites in rat brain. Allosteric effects of ropizine.
Dextromethorphan (DM) binds to high- and low-affinity sites in the rat brain. The high-affinity DM binding is inhibited by nonnarcotic antitussives, opipramol and sigma ligands with nanomolar affinities. Computer-assisted modeling of homologous and heterologous competition studies between DM and (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(+)-3-PPP] were performed at pH 8.4. These experiments confirmed the existence of the common high-affinity DM1/sigma 1 site (R1) for which DM and (+)-3-PPP have Kd values of 20 and 10 nM, respectively. DM also binds to a second high-affinity site (R2, Kd, 20 nM) for which (+)-3-PPP has only micromolar affinity. Similarly, (+)-3-PPP binds to another high-affinity site (R3, Kd, 60 nM) for which DM has micromolar affinity. The common high-affinity DM1/sigma 1 site is allosterically modulated by the anticonvulsant ropizine, and is (+)-pentazocine sensitive, as is the homologous site in the guinea pig. However, in the rat the common DM1/sigma 1 site is 10 times smaller than in the guinea pig. This explains the apparently different effects of the allosteric modifiers in both species. The multiplicity of binding sites for DM and (+)-3-PPP resolved in this investigation will help to establish the physiological role and the pharmacological potential of the different sites. Meanwhile, the pharmacological effects of DM and sigma ligands cannot be summarily attributed to any particular binding site or receptor. This investigation also demonstrates that the use of multiple labeled and unlabeled ligands, combined with computer-assisted modeling, is essential to resolve multiple binding sites with similar affinities and to characterize the complex effects of allosteric modifiers.
[Hypothyroid myopathy. Physiopathological approach].
Patients with thyroid deficiency often complain of muscular weakness, exercise intolerance, cramps and excessive fatiguability. Hypothyroidism induces a metabolic myopathy, with a fall of the energetic production, and especially of the mitochondrial metabolism. This is due to a global inhibition of the main oxidative pathways (substrate incorporation, substrate oxidation) and of the respiratory chain. A diminished energetic consumption is partially related to a transition in the myosin isoforms, which express a slower ATPase, and to an impairment of the trans-sarcolemic transports. Exercise intolerance could be due to an abnormal recruitment of several metabolic pathways, such as glycolysis, related to the mitochondrial metabolism impairment, and including an abnormal accumulation of protons and monovalent phosphate ions, which are involved in the alteration of the actin-myosin interaction, and also by an abnormal Ca++ metabolism. The decreased number of NA+/K+ ATPase dependent pumps could imply an abnormal intracellular Na+ level and explain the frequent disorders of the membrane excitability.
Do women under the care of family physicians have fewer cesarean sections?
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Multiple leiomyomas of the skin in RA.
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[Magnetic resonance imaging in lupic chorea].
A case of disseminated lupus erythematosus with chorea is reported. CT was normal. Magnetic resonance imaging showed multiple focal lesions on T2-weighted sequences, predominating in the periventricular white matter. This MRI pattern did not change in a second MRI investigation, 7 months later. The contribution of MRI to our understanding of the neurolupus pathophysiology is discussed.
[Traumatic tricuspid insufficiency with a right-to-left shunt and heart luxation].
Traumatic tricuspid insufficiency (TTI) with a right-to-left shunt through a patent foramen ovale associated with a cardiac herniation was identified in a 39-year-old man with severe hypoxemia. All reported cases of TTI with a right-to-left shunt are reviewed, the technical aspects of repair described and the physiologic mechanisms discussed.
Examinations of the relative fluidity in cerebrovascular disease patients.
Parallel with the increasing incidence of cerebrovascular diseases, and the limitations of possible surgical methods, the importance of drug therapy has significantly increased. Due to our knowledge of haemorheology the effectiveness of therapies may be measured by means of useful circulatory markers. In course of our research activities of one and a half decades the changes in blood viscosity were measured during vinpocetine therapy, and were compared to the changes of haematocrit and mean corpuscular volume (MCV) values. The effect of vinpocetine and secale alkaloids or vinpocetine and pentoxifylline were compared by sequential analysis in other cases. The results of these examinations proved that vinpocetine is effective in both short and long-term therapy.
[Granulomatous hypophysitis. Report of three cases and review of the literature].
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[Mesonephroid hyperplasia of the uterine cervix].
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[Heart-skin syndrome and cardiac myxoma: presentation of a case and clinical experience of 17 years].
Between 1971 and 1988, cardiac myxoma was identified in 13 (0.003%) of 4000 patients who underwent open-heart surgery at the hôpital du Sacré-Coeur in Montreal. One patient with multiple right atrial tumours also had abnormal cutaneous pigmentation compatible with the recently identified syndrome of "Carney's complex." This syndrome has also been associated with endocrine abnormalities such as primary nodular adrenal hyperplasia, with or without Cushing's syndrome. The authors review the literature and compare the findings with their experience in the surgical treatment of cardiac myxomas.
Activation of neurohumoral systems following acute myocardial infarction.
Previous studies have indicated that patients with an acute myocardial infarction have marked activation of all neurohumoral systems on admission to the hospital. This activation begins to subside within the first 72 hours so that by 7-10 days, all plasma neurohormones have returned to normal. The only documented exceptions were found to occur in patients with left ventricular dysfunction and overt heart failure, where both plasma renin activity and atrial natriuretic peptide were increased, and in patients with left ventricular dysfunction but no overt heart failure, where only atrial natriuretic peptide was increased. Although these studies suggest that neurohumoral activation rarely occurs at the time of hospital discharge, they were small and may have missed an important subgroup of patients with persistent neurohumoral activation. In the Survival and Ventricular Enlargement (SAVE) study, 522 patients had plasma neurohumoral levels measured at a mean of 12 days postinfarction. All SAVE patients had left ventricular dysfunction (left ventricular ejection fraction less than or equal to 40%), but no overt heart failure. In this group of patients, all neurohumoral levels (plasma renin activity, norepinephrine, arginine vasopressin, and atrial natriuretic peptide) were found to be increased compared with age-matched control subjects. These results indicate that, in fact, a subgroup of patients without overt heart failure has persistent neurohumoral activation at the time of hospital discharge postinfarction, and that this activation involves several neurohumoral systems. Since patients with persistent neurohumoral activation postinfarction are likely those most at risk of developing complications and the ones most likely to benefit from pharmacologic interventions blunting the effects of neurohumoral activation, measurement of predischarge neurohumoral levels may be useful.
Acute respiratory infections as an important cause of childhood deaths in South Africa.
Compared with other major preventable childhood diseases, such as diarrhoea, acute respiratory infections (ARI) have received comparatively little attention as an important cause of death in children. In this study of mortality from ARI in South Africa, national data was examined for the period 1968-1985, and data for Greater Cape Town for 1987. Almost 90% of ARI deaths were attributable to pneumonia and large inter-group differences were found that favoured whites and Asians over blacks and coloureds. For example, during 1980-1985 the mortality rate for pneumonia in coloured infants under 1 year of age was 11 times that observed in whites (88 v. 981/100,000). Pneumonia accounted for 14.5% of coloured and 12.7% of black deaths under 1 year of age during this period, compared with 6.7% of white and Asian deaths. The mortality rates from pneumonia declined substantially (50%) over the 18-year period in whites, coloureds and Asians. Sequential data for blacks is not available. There was a marked seasonality of deaths among coloured and Asian infants, with rates peaking in winter months. In Cape Town, pneumonia is now a more important cause of death among white and coloured children than diarrhoea, while it ranks with diarrhoea as a cause of death in black children. In all population groups, death rates from ARI are from 7 times to 270 times greater than those recorded in Western European countries. Studies are urgently required to discover why South African children suffer such a high mortality from ARI and how these deaths can be prevented.
[Rise in CA 125 in a case of multivisceral tuberculosis without effusion].
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