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Biomedical subjects

C Colin

Publications and source records attributed to C Colin.

At least 109 records · Page 6Linked to original sources
PubMed1995

[Management of myocardial infarction in the Rhone-Alps area. Are there many variations in practice?].

The aim of this study was to determine the diagnostic and therapeutic strategies after myocardial infarction and to examine variations in medical and surgical practice with respect to the severity of disease, status of the hospital and patients' characteristics. The method used was a prospective study with follow-up at 30 days and 18 months. The subjects came from an exhaustive cohort of all patients admitted to hospital for myocardial infarction during the month of April 1991 in 57 public and private hospitals in the Rhone-Alps region (n = 311). The patients were identified after admission by consulting physicians of the Department of Social Security. The study included all patients with acute myocardial infarction with at least two of the three usual diagnostic criteria (prolonged, constrictive chest pain, enzyme increases and electrocardiographic changes). The study excluded patients who were dead before arrival at hospital. The parameters analysed included the clinical management, use of echocardiography, exercise stress testing, myocardial scintigraphy, coronary angiography, thrombolysis, angioplasty and coronary bypass surgery in the first 30 days after admission. The severity of infarction was assessed by seven clinical, enzymatic and electrocardiographic criteria by physicians from the Department of Social Security (pain, syncope, shock, left ventricular dysfunction, elevation of CPK > 1000 IU, anterior or extensive necrosis, arrhythmias). The mortality rate of this cohort was calculated from hospital statistics and then by enquiring in the town halls of the region. The demographic features of the cohort were marked by a predominance of men (69.5%) and a relatively high mean age (69 years; 23% over 80 years). Complementary investigations were used with the following frequencies: echocardiography, 61.1%; coronary angiography, 26.4%; exercise stress testing 22.8%; myocardial scintigraphy, 5.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of dietary vitamin D on magnesium absorption and bone mineral contents in pigs on normal magnesium intakes.

The effects of three dietary levels of vitamin D (500, 1500 and 3000 IU/kg diet) on magnesium metabolism and on some bone parameters related to bone mineralization were studied in vitamin D-repleted pigs fed normal magnesium intakes (0.2 per cent) for two months. Apparent absorption and retention was measured in 10-day balance studies (prior to slaughter) in three groups of four 10-week old pigs. Except for vitamin D, the pigs received the same diet which met the recommended dietary allowances for growing pigs. The highest vitamin D level used was only three times the recommended level in French pig husbandry. At slaughter, the fibula and two main metatarsals (right hind leg) were collected to determine bone breaking strength, apparent density and bone mineral (ash, calcium, magnesium) contents. Blood was collected to determine plasma concentrations of calcium, magnesium and vitamin D metabolites. Magnesium absorption increased linearly from 28-39 per cent intake with increasing dietary vitamin D. Urinary magnesium was not affected, thus magnesium retention also increased linearly as a function of vitamin D intake. Plasma calcium and magnesium were not altered by vitamin D. Plasma 25-hydroxycholecalciferol concentrations reflected vitamin D intakes, while plasma 1,25 dihydroxycholecalciferol was unchanged. Density, breaking strength and mineral contents of the bones were lower in the pigs fed 1500 or 3000 than in those fed 500 IU vitamin D/kg diet. This suggests that bone resorption was stimulated by the higher dietary vitamin D. Thus, vitamin D at physiological doses may enhance magnesium absorption in non previously vitamin D-depleted pigs fed diets with abundant magnesium. This nutritional situation may help explain the predominant bone-resorbing effect of vitamin D supplementation.

Absorption↗
PubMed1995

[Vaginal trial or repeat cesarean in a woman with a previous cesarean section? An example of analysis of medical decision making].

Decision making analysis is a probability-based quantitative method used for decision making in particularly uncertain circumstances. Such analysis can be used to develop a model for medical decision making and help to determine the best strategy for a given clinical situation. A decision tree includes all the necessary choices and the corresponding consequences. Statistical analysis of the decisional tree orients the decision to the one with the smallest risk and the greatest advantages. This work describes the basis of the methodology and the decision analysis using a simple example in obstetrics: repeat cesarean or uterus trial in women with a history of cesarean section. The analysis of the decision, based on data in the literature, demonstrates the choice for the uterin trial because of the lower maternal morbidity.

Cesarean Section↗
PubMed1994

Data quality in a DRG-based information system.

The aim of this study initiated in May 1990 was to evaluate the quality of the medical data collected from the main hospital of the "Hospices Civils de Lyon", Edouard Herriot Hospital. We studied a random sample of 593 discharge abstracts from 12 wards of the hospital. Quality control was performed by checking multi-hospitalized patients' personal data, checking that each discharge abstract was exhaustive, examining the quality of abstracting, studying diagnoses and medical procedures coding, and checking data entry. Assessment of personal data showed a 4.4% error rate. It was mainly accounted for by spelling mistakes in surnames and first names, and mistakes in dates of birth. The quality of a discharge abstract was estimated according to the two purposes of the medical information system: description of hospital morbidity per patient and Diagnosis Related Group's case mix. Error rates in discharge abstracts were expressed in two ways: an overall rate for errors of concordance between Discharge Abstracts and Medical Records, and a specific rate for errors modifying classification in Diagnosis Related Groups (DRG). For abstracting medical information, these error rates were 11.5% (SE +/- 2.2) and 7.5% (SE +/- 1.9) respectively. For coding diagnoses and procedures, they were 11.4% (SE +/- 1.5) and 1.3% (SE +/- 0.5) respectively. For data entry on the computerized data base, the error rate was 2% (SE +/- 0.5) and 0.2% (SE +/- 0.05). Quality control must be performed regularly because it demonstrates the degree of participation from health care teams and the coherence of the database.(ABSTRACT TRUNCATED AT 250 WORDS)

Data Collection↗
PubMed1994

[Tamoxifen in the treatment of breast cancer].

Tamoxifen is the most often prescribed non steroidal antioestrogenic agent in the world for breast cancer. Worldwide collaboration. has centralized the results, of different trials throughout the world on oral adjuvant therapy in the early stages of breast cancer. A significative regression of the tumour was observed in most cases. Moreover, recent epidemiological studies suggest that tamoxifen could prevent new contralateral primary tumours. The risk of the disease should thus be reduced by the prophylactic use of antioestrogens such as tamoxifen. Investigations using a variety of models have evaluated the effect of tamoxifen on tumour promotion and cell growth. Tamoxifen-induced growth inhibition is associated with major changes in biochemical events in cultured human breast cancer cells including cell proliferation or growth factor production. Growth inhibition of oestrogen-responsive human breast cancer cells is associated with an induced secretion of autoinhibitory polypeptides (TGF beta) and an antagonistic effect on the synthesis of proliferative proteins (TGF alpha,...). The first step in the mechanism of action of the drug is binding of tamoxifen to the oestrogen receptors. Development of resistance to tamoxifen treatment is a great problem in treatment of breast cancer patients and the mechanism of resistance will require further study: under the influence of the drug, tumours could become remodelled as selected subpopulations emerge resistant-tamoxifen. The fact that some breast cancers which are oestrogen receptor-negative respond to antioestrogen suggests that parallel but separate pathways for oestrogen and antioestrogen action may exist. This paper summarizes the results of the most recent studies concerning this promising drug.

Breast Neoplasms↗
PubMed1994

[Treatment of cystic mastopathy with puncture and administration of an LHRH analogue].

Goserelin depot (Zoladex) was administered for 6 months to seven women with premenopausal gross cystic breast disease. For each patient at least three cysts were followed up by ultrasonography and radiography (21 cysts in total). Hormone assessments showed a suppression of serum oestradiol at 8-12 weeks. Two-thirds of the observed cysts continued to grow after 8-12 weeks, but two-thirds had decreased in size by 20-24 weeks and this decrease had continued 12 weeks after cessation of treatment. Cysts containing fluid with a higher Na+/K+ ratio (extracellular fluid type) responded earlier to treatment. These patients had received other hormone treatments without success. The LHRH analogue treatment seems to be a promising and effective adjuvant to aspiration in the management of gross cystic breast disease, although maximal efficacy was only observed after 20-24 weeks.

Adult↗
PubMed1994

Influence of exogenous porcine growth hormone on magnesium metabolism in intact pigs receiving normal magnesium intakes.

The magnesium balance and plasma magnesium levels of intact growing pigs treated with recombinant porcine growth hormone (100 micrograms/kg body weight/d) for 2 months were measured. Growth hormone treatment did not change plasma magnesium, but it markedly increased magnesium absorption and retention. This agrees with our finding of adequately mineralized newly formed bone in intact pigs given growth hormone.

Animals↗
PubMed1993

Stimulation of the secretion of latent cysteine proteinase activity by tumor necrosis factor alpha and interleukin-1.

OBJECTIVE: Cultured synovial fibroblast-like cells from 3 patients with rheumatoid arthritis (RA) and 3 patients with osteoarthritis (OA) were evaluated for their potential to secrete cysteine proteinases spontaneously and after stimulation by tumor necrosis factor alpha (TNF alpha) or interleukin-1 (IL-1). METHODS: Culture media and cell lysates were analyzed before and after high performance liquid chromatography (HPLC) using the enzymatic substrate, Z-Phe-Arg-AMC, and by immunoblotting with anti-cathepsin B antiserum. Immunolocalization of cathepsin B was studied on cell monolayers. RESULTS: Latent cysteine proteinase activity was found to be secreted spontaneously by cultured synovial fibroblast-like cells. This activity was increased after treatment with either TNF alpha or IL-1. Stimulated protease activity was eluted by HPLC at a peak coincident with that of purified cathepsin B. By immunoblot, cell supernatants contained a 43-kd form of cathepsin B, while cell lysates contained a 30-kd form, consistent, respectively, with cathepsin B before and after cleavage of its propeptide. An intracellular increase in cathepsin B after treatment with TNF alpha was also seen with immunohistochemical studies. CONCLUSION: TNF alpha (in the 6 cases studied) and IL-1 (in 4 cases) stimulated the secretion of a latent cysteine proteinase activity from synovial fibroblast-like cells, which appears to represent primarily cathepsin B.

Arthritis, Rheumatoid↗
PubMed1993

Migration pathways, differentiation and survival of macroglial cells from a xenograft implanted into the thalamus of newborn mice.

Embryonic rabbit corpus callosum transplants were grafted into thalamus of newborn shiverer mice in order to compare the fates of oligodendroglial and astroglial cells derived from the transplants. Our model allowed the identification of the two populations of macroglial cells. The thalamus was chosen as site of implantation because of its situation at a crossroad of numerous neuronal fascicles. Previous studies, where the dorsal striatum was used as site of implantation, had shown that corpus callosum was one of the favorite routes of migration for both populations of macroglial cells. In the present study special attention was given to the comparison of the migration pathways and areas of settlement of implanted astroglia and oligodendroglia. The internal capsule, the medial lemniscus, the crus cerebri and the thalamic radiations were used by both populations of transplant derived macroglial cells for their migrations through the host parenchyma. They integrated into the host tissue on these routes or further away in areas such as the putamen, the mesencephalon or the colliculi. Signs of degeneration of the implanted astroglia were often observed after 1 month post-implantation.

Animals↗
PubMed1993

[Analysis of the medical decision].

Analysis of clinical decision making is a quantitative method using probabilities to evaluate the process in uncertain situations. It provides a model of clinical decision making by integrating experimental and epidemiological data, the opinions of specialists and an assessment of the patient's state of health. There is also a place for the integration of the patients' opinions and of their quality of life. Using this information and eventually associating the cost of management, analysis of decision making tries to demonstrate a preference for a given strategy in a given clinical or public health problem. This article presents the methodological basis of analysis of decision making using a simple example of clinical cardiological practice and discusses the value of this method for debating a clinical choice with criteria integrating the patients' quality of life and the cost to society.

Cost of Illness↗
PubMed1992

[Medico-economic strategy for biliary lithiasis].

The purpose of this study was to assess the relevance of a medico-economic evaluation of gallstones. In other words, would it be possible to define economic criteria that would permit to select the best therapeutic method whilst respecting medical ethics? The frequency of gallstones, the high consumption of goods and medical services they require and the important loss of productivity that ensues justify this approach. The medical literature and a number of experts have made it possible to evaluate the advantages and drawbacks of each therapeutic method by defining its indications according to criteria of effectiveness such as duration of survival, quality of life of asymptomatic patients, gallbladder clearance, etc. We have tried to find out whether the introduction of medico-economic criteria in this pathology was likely to modify the various therapeutic methods available at present. We give here three examples. The first one is that of asymptomatic gallstones where the introduction of a cost/effectiveness ratio let to the conclusion that abstention is better than surgical treatment. The second example is a comparison of costs between cholecystectomy and medical treatment in high risk patients; the result was that surgery is preferable at the age of 50 years and medical treatment from 70 years onward. Finally, a comparison between surgery and lithotrity including the cost/effectiveness ratio concluded in favour of surgery. However, ethical, methodological and conceptual problems taking into account the value of human life, the difficulty to evaluate the quality of life and exterior incitations make it necessary to moderate the practical applications of these results.

Cholelithiasis↗
PubMed1992

[Which anti-ischemic treatment can be prescribed during and after the acute phase of myocardial infarction?].

After myocardial infarction, calcium channel blockers are the most prescribed anti-ischemic drugs followed by nitrate derivatives and beta blockers. In order to assess whether this attitude is justified by published data on their efficacy, a meta-analysis of trials of anti-ischemic drugs in myocardial infarction was performed. The early mortality was 13.3% in the group treated by IV nitrates in the acute phase of myocardial infarction and 17.2% in control groups, reducing the risk by a quarter (95% confidence interval of the odds ratio (CI): 0.55-0.95). When all nitrate derivative trials were grouped together, the reduction in the risk of death of 21% was significant (from 15% to 11.8%) (CI: 0.59-0.94). Although oral nitrate derivatives introduced during the acute phase and continued for several weeks induced a non-significant reduction in mortality of 16%, when given intravenously, the benefits on early and longer term mortality were unquestionable. The mortality was 9.8% in the groups treated by calcium channel blockers and 9.3% in control groups (NS); the recurrent infarct rate was 4.8% and 5.4% respectively (NS). In this family of drugs, there was no product which distinguished itself from the others with regard to beneficial or adverse effects. The early mortality decreased from 9.2% to 8.2% in the groups treated by oral beta-blockade--a risk reduction of 10% (NS) and from 4.2% to 3.7% with intravenous beta-blockers--a risk reduction of 12% (p = 0.03). Late mortality decreased from 9.4% to 7.6%, a reduction of 20% (p < 0.00001) in long term trials.2+ contraindication of betablockers in patients without cardiac failure.

Adrenergic beta-Antagonists↗
PubMed1992

[Cytological and histological studies in stereotactic punctures of non-palpable solid breast lesions].

Cytologic aspiration and core biopsy were performed on 50 nonpalpable breast lesions by using a stereotactic localization technique. Cytologic and histologic results were correlated with mammographic findings and therapeutic decisions were based on the results of both procedures. Representative material was obtained in 100% of the lesions. The sensitivity was 90% and specificity was 97.5%. The predictive values were high except for the predictive value of a negative histologic finding in a suspicious cluster of microcalcifications (50%).

Biopsy, Needle↗
PubMed1991

Lipid peroxidation and benzo[a]pyrene activation to mutagenic metabolites: in vivo influence of vitamins A, E and C and glutathione in both dietary vitamin A sufficiency and deficiency.

Rats fed with either a sufficient-vitamin A or a vitamin A-free diet were pretreated with 750 mg/kg body weight of retinyl palmitate, alpha-tocopherol acetate, ascorbic acid or glutathione. Benzo[a]pyrene (BaP) metabolism and BaP-induced mutagenesis in Salmonella typhimurium TA98 were investigated and related to lipid peroxidation activities in postmitochondrial (S9) liver fraction. The microsomal mixed-function oxidase activities were decreased by vitamin A deficiency and weakly affected by scavenger treatment. The rate of lipid peroxidation of microsomal membranes was unaffected by vitamin A deficiency because of decreased polyunsaturated fatty acids and increased vitamin E contents. However, lipid peroxidation was decreased by pretreatment with fat-soluble vitamins (chiefly vitamin E) and increased by ascorbic acid. Within each experimental group both BaP metabolism and BaP mutagenic activity were closely correlated with the rate of lipid peroxidation. In vitamin A deficiency, the increased BaP metabolism and mutagenicity could be related to a decrease in cytosolic contents of scavengers (vitamin A and glutathione). In Ames test conditions, the free radical pathway became a route for BaP metabolism and thus the BaP activation to mutagenic metabolites is related to the cellular status in free radical scavengers.

Animals↗
PubMed1991

Meta-analysis.

Meta-analysis corresponds to all systematic methods which use statistical techniques for combining results from several independent studies. The aim is to get a consistent estimation of the global effect of a procedure on a specified outcome. The technique allows us to increase the power of statistical testing, and to get information which cannot be drawn from one individual study. Two approaches are possible, and often combined: the qualitative approach consists of weighing various studies according to their methodological quality; the quantitative approach consists of pooling the results of different studies, in order to generate results with a higher statistical power. A meta-analysis is a long and rigorous process, which follows several steps: statement of objectives; definition of articles inclusion and exclusion criteria; literature search; collection of data and evaluation of the quality of each study; tests for homogeneity; pooling; sensitivity analyses; presentation of results; and conclusions. Meta-analysis has several advantages: it estimates the size of an effect; it improves the generalizability; it compels to rigor; it lessens the part of subjectivity. When meta-analysis is cautiously and properly done, it brings new useful information, and helps physicians and health policy makers in answering to a specific question.

Data Collection↗