Biomedical subjects
B Courvoisier
Publications and source records attributed to B Courvoisier.
[10 years of Central Committee of Medical Ethics].
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[Autonomy of the patient and of the physician in resuscitation or terminal care situations. The value of advanced directives by the patient].
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[Effect of 2 phosphonates on the osteolysis induced by tumor extracts].
An in-vitro model is proposed to test the potential effect of diphosphonates in treatment or preventing bone metastases. This model involves culturing of neonatal mice calvaria in sterile conditions in an appropriate medium and measuring 45Ca release from bone to medium, the mice being injected with 45Ca on the day of birth. Tumour extracts added to the medium usually increase the bone lysis; this effect is significantly decreased when the mice have been treated with either ethane-hydroxy-diphosphonate (EHDP) or dichloromethylene-diphosphonate (Cl2MDP). These experiments represent a first step in a group of experiments with a view to clinical trials in cases of bone metastases.
[is there an osteomalacia component in femur neck fractures?].
In 29 patients with fractures of the femoral neck (group A) and 22 patients operated on for osteoarthritis of the hip (group) B), plasma levels of 25-hydroxycholecalciferol (25-OH-D3) were compared with the results of histological bone tests. A third group of 19 patients at the Geriatric hospital served as a control in this age group for 25-OH-D3 values (group C). The average level of 25-OH-D3 was 9.64 +/- 5.8 micrograms/l in group A and 13.25 +/- 7.6 micrograms/l in group B. This difference is not significant. On the other hand, the difference between groups B and C (9.31 +/- 4.04) is significant (2 p less than 0.05). Evaluation of the histological sections did not reveal evidence of osteomalacia. Generally speaking, the levels of plasma 25-OH-D3 in these patients were low, but without signs of osteomalacia on histological evaluation.
[Bartter's syndrome, chondrocalcinosis and hypomagnesemia].
In two cases of Bartter's syndrome with hypomagnesaemia the authors report radiological findings typical of chondrocalcinosis associated with joint symptoms corresponding to this condition. In Bartter's syndrome there is, in addition to hypokalaemic alkalosis, often concomitant magnesium depletion which has marked repercussions with respect to both physiopathology and symptomatology. In particular, hypomagnesaemia could well be important in the pathogenesis of chondrocalcinosis through two simultaneous mechanisms: by reducing the activity of pyrophosphatases and by facilitating the crystallisation of pyrophosphates. These mechanisms could explain the association of Bartter's syndrome and chondrocalcinosis, which is described here for the first time.
The clinical measurement of urinary total hydroxyproline excretion.
The effect of dietary control on the day-to-day variation in total hydroxyproline excretion has been examined in two studies. In the first, a normal volunteer ate a controlled diet containing varying gelatin supplements for several weeks. In the second, the effect of removing hydroxyproline-containing foods from the diets of 8 volunteers was examined. Both studies confirm that the day-to-day variation in total hydroxyproline excretion falls when the gelatin content of the diet is decreased, whether the results are expressed as total hydroxyproline excretion rate or as the total hydroxyproline: creatinine ratio. This fall in variation takes place within 24 h of dietary control beginning and therefore longer periods of dietary restrictions to achieve optimum precision in the measurement of total hydroxyproline are unnecessary. For some analytical methods, results are better expressed as the ratio total hydroxyproline:creatinine than as the total hydroxyproline excretion rate.
[Effect of the sun on circulating 25-hydroxycalciferol levels in normal subjects in Switzerland].
The principal source of human natural vitamin D is cholecalciferol produced in skin by the action of ultraviolet light. Plasma levels of 25-hydroxyvitamin D (25-OH-D), the hepatic metabolite of cholecalciferol, increased by 39.3% in 20 healthy young Swiss subjects after a 3-week holiday in the sun. Significant increases of circulating 25-OH-D (p smaller than 0.001) were found as much as 2 months later when compared with a group not deliberately exposed to sunshine. A short vacation in the sun therefore appears to be beneficial in replenishing vitamin D body stores.
Total urinary and free serum hydroxyproline in metastatic bone disease.
The present study examines the possibility of correlation between free serum and urinary total hydroxyproline and whether this correlation can be applied to clinical conditions. The correlation between the two indices was 0.80 (P less than 0.001) in 18 patients, mostly suffering from malignant disease. On comparing the same measurements in 37 patients, all with known metastatic bone disease, we found 29/37 normal results for free serum hydroxyproline, whereas only 2/37 values of urinary total hydroxyproline were normal. The authors therefore conclude that urinary total hydroxyproline, measured as the ratio hydroxyproline/creatinine in a fresh specimen of early-morning urine, is the best index of collagen breakdown in metastatic bone disease and preferable to measurement of free serum hydroxyproline.
[Industrial fluorosis. Multidisciplinary study on 43 workmen in the aluminum industry].
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[Incidence of lactose intolerance in postmenopausal osteoporosis].
The incidence of lactose intolerance was determined in 31 women with idiopathic postmenopausal osteoporosis. Nine subjects exhibited a pathological rise in blood glucose (less than 20 mg/100 ml) after receiving 50 g lactose. The absorption of glucose and galactose, xylose, and fat was normal in the 31 patients. Daily intake of calcium was below the normal range in 3 subjects with and in 6 subjects without lactose intolerance. The association between lactase deficiency and osteoporosis is stressed.
[Measurements of blood citrates in neoplasms with bone metastases].
Blood citrate was measured in 49 patients with cancer, with or without bone metastases, and in 53 normal subjects. It is significantly higher (p less than 0.001) in patients with bone metastases than in normal subjects or patients without bone metastases. In normal subjects, blood citrate is higher in summer than in winter and higher in older people. The theoretical and practical interest of these observations is discussed.
[Decrease of intestinal absorption of 47-calcium in chronic alcoholism].
Intestinal 47-calcium absorption has been studied in 34 chronic alcoholics, 17 of whom were cirrhotics (group A) and 17 non-cirrhotics (group B). These patients were compared with 44 normal subjects (group C). In group C, the 47Ca 2 h plasma % of the dose showed a significant negative correlation to the total body weight (p less than 0.001) and a positive correlation with the serum albumin (p less than 0.05). The mean intestinal absorption of 47Ca expressed as 2 h plasma % of the dose multiplied by total body weight was 131 +/- SD 52 in group A and 136 +/- SD 71 in group B. These two means are significantly low (p less than 0.001 and p less than 0.002 respectively) in relation to that found in group C (168 +/- SD 32). These results suggest that intestinal calcium absorption is diminished in chronic alcoholism even in the absence of hepatic cirrhosis.
[25-hydroxy vitamin D deficiency with reduction of intestinal calcium absorption and bone density in chronic alcoholism].
Plasma levels of 25-hydroxycalciferol (25-OH-D), 47-calcium intestinal absorption, bone mineral content and the biologic parameters of phospho-calcium metabolism were studied in 30 chronic alcoholics, 15 with Laennec's cirrhosis (group A) and 15 without (group B). These patients were compared with 27 normal subjects. In group A, the mean 25-OH-D plasma level was 23.7 +/- SD 18.5 microgram/l and in group B 35.2 +/- SD 21.8 microgram/l. These mean levels were lower than those of the control group, which were 57.2 +/- SD 22.5 microgram/l (p less than 0.001). The mean value of the 47Ca intestinal absorption, measured as the percentage of the ingested dose per litre of plasma and multiplied by the body weight, was also significantly lower in group A, which was 140 +/- SD 47 (p less than 0.01), and in group B, which was 145 +/- SD 69 (p less than 0.05), compared with the normal subjects whose average was 182 +/- SD 45.6. Similarly, the total plasma calcium was low: 1.99 +/- SD 0.24 mmol/l in all the alcoholics, while that of the control group was 2.22 +/- SD 0.18 mmol/l (p less than 0.001). For the 30 chronic alcoholics there was a positive correlation between 25-OH-D and 47Ca intestinal absorption, (r = 0.484; p less than 0.004). This suggests that in chronic alcoholism the deficiency of 25-OH-D induces a diminution of the intestinal absorption of calcium which, in the long term, can result in bone demineralization evidenced in the patients studied by a bone mineral content lower than normal (p less than 0.001).
[Hydroxyproline in the diagnosis of bone metastases in breast cancer].
15 patients with breast cancer and proven bone metastases have been studied. Free serum and total urinary hydroxyproline were measured and the ratio (hydroxyproline/creatinine) - 100 in a morning urine specimen was calculated. The preliminary results show elevated free serum hydroxyproline in 8 of 15 patients; total urinary hydroxyproline in a 24-h collection and the ratio hydroxyproline/creatine in a morning urine specimen were elevated in all cases. These results agree with those of the literature. Further studies of free hydroxyproline and of the ratio hydroxyproline/ creatinine in a morning urine specimen in similar patients with provide more information on the possibility of using these measurements, alone or in combination, for the early detection or follow-up under therapy of bone metastases.
[Morphological research in the study of bone diseases].
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[Problems in mineral and bone metabolism in chronic renal insufficiency].
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[Industrial fluorosis].
43 potroom workers (aluminium industry) with fluorosis have been compared with 18 foundry workers of the same age, but who had never been exposed to fluorides. Clinical examination revealed a higher incidence of articular pain and limitation of motion in the exposed group. The diagnosis of fluorosis is not only clinical but calls for other investigations such as urinary fluoride determination, bone radiology and, above all, bone biopsy for fluoride determination, histology and microradiography.