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Biomedical subjects

C Colin

Publications and source records attributed to C Colin.

At least 19 recordsLinked to original sources
PubMed1995

Fine structure of astroglial integration into host brain following xenografting.

Previous investigations showed that fragments of fetal rabbit brain transplanted into striatum of neonatal shiverer mouse give rise to cells that migrate through host tissue and differentiate into astroglia and oligodendroglia within 2 weeks. We studied the integration of transplanted astroglia at the ultrastructural level using pre-embedding labeling with a monoclonal antibody which recognizes an epitope associated with rabbit but not mouse glial fibrillary acidic protein. The morphology of early migrating donor cells does not distinguish them from cells arising in host germinal matrix. Once the cells complete their migration they integrate into host brain in a structurally normal manner. Transplanted astroglia form perivascular foot plates with host capillaries. They also send extensive processes into the neuropil where intimate contacts with neurons and synaptic structures are formed. Oligodendroglia send processes to nearby axons where they form normal-appearing myelin. During the rejection process, which may begin at 4 weeks, donor astroglia show evidence of reaction with increased intermediate filament content. Donor cells are attacked by leukocytes, including eosinophils, and subsequently degenerate. We conclude that cross-species transplantation of glial cells can result in entirely normal structural integration into host brain.

Animals↗
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↗
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

Descriptive analysis of a series of operations for prostatic adenomas in inhabitants of Lyon, France, in 1988. Urological College of Lyon.

A retrospective, population-based study was conducted in Lyon, France, to elucidate the benefits and risks of a treatment for prostatic adenoma (benign prostatic hyperplasia). Case records were reviewed for all prostatectomies performed on patients in Lyon in 1988 for benign prostatic hyperplasia. Data were obtained from all records of public and private hospitals. Of 408 procedures, 312 involved endourethral resection (transurethral resection) and 96 open surgery. The mean weight of resected tissue was 20.3 +/- 0.9 g after endourethral resection and 71.7 +/- 6.4 g after open surgery. About 20% of the resections took place in a university hospital center, 43% in a not-for-profit private hospital, and 37% in a private clinic; there were eight deaths in the first 3 postoperative months, and 11 patients required hospitalization for urologic complications. Length of hospital stay uniquely correlated with age and type of surgery.

Aged↗
PubMed1991

[Hormone substitution therapy in menopause and risk of breast cancer].

If the administration of an estrogen alone increases the risk of breast and endometrium cancer, the addition of a progesterone derivative does not seem to change completely the risk of breast cancer whilst it clearly decreases that of the uterine one. One must be careful in making a large extrapolation of the data on the endometrium (progestogens inhibit the mitotic action of estrogens) to that on the mammary epithelium (inhibition of the estrogen activity at the canal level but synergy with estrogens at the lobe level). The high tissue concentrations of oestradiol at the mammary gland level after menopause could partly explain the small influence of exogenous estrogens administered alone and/or in combination with progestogens on the transformation of a gland already oversaturated with estrogens.

Breast Neoplasms↗
PubMed1990

Influence of early neonatal phenobarbital exposure on cerebral energy metabolism and behavior.

The influence of an early chronic phenobarbital (PhB) exposure on local cerebral glucose utilization (LCGU) and on behavior was studied in the rat. The animals were treated from Postnatal Day 2 to Postnatal Day 35 by a daily injection of 50 mg/kg PhB or by saline and tested between 10 and 35 days for short-term effects of the drug on LCGU and between 70 and 90 days for long-term effects of PhB on LCGU and behavior. PhB induced short- and long-lasting reductions in the overall rates of LCGU in hippocampal and cerebellar areas, but no significant changes in LCGU in the different cell layers of these two cerebral areas. PhB also changed the pattern of maturation of the rates of LCGU as compared to control subjects. The barbiturate treatment induced a decrease in the exploratory behavior of PhB- as compared to saline-treated rats in the open field, as well as a significant 25% decrease in the rate of spontaneous alternation with delay. In addition, PhB-treated rats needed significantly more time than control animals to perform their trials in the nonrewarded T maze testing. However, the neonatal barbiturate exposure did not induce changes in performances of adult rats in the rewarded eight arm maze. The results of the present study show that there is no apparent correlation between the rates of energy metabolism in the hippocampus and the impairment of learning abilities of adult rats in behavioral tests related to the hippocampus.

Animals↗
PubMed1990

Immunodetection of the metastasis-associated laminin receptor in human breast cancer cells obtained by fine-needle aspiration biopsy.

Fine-needle aspiration biopsy of the breast is a very useful technique for the evaluation of a suspect lesion before surgical removal. Increased expression of the 67-kd laminin receptor has been associated with the metastatic phenotype of cancer cells, particularly in colon and breast cancers. In this study, the expression of laminin receptor was evaluated using the immunoperoxidase technique in 81 breast aspirates (26 benign and 55 neoplastic lesions). Cells obtained from benign samples exhibited a low level of laminin receptor antigen detected by affinity-purified antibody raised against a cDNA-derived laminin receptor peptide. In contrast, 71% of smears obtained from malignant breast lesions contained cells that were strongly stained by the antibody. Heterogeneous expression of the laminin receptor was noted in both breast aspirates and fixed tissue specimens. These data suggest that the immunodetection of laminin receptor in cells obtained by fine-needle aspiration of breast lesions could be a valuable adjunct in the prognostic evaluation of breast lesions.

Antibodies↗
PubMed1990

Lymphokine-activated killer cell expansion for clinical trials of adoptive immunotherapy with interleukin-2: optimization of the culture technique.

On leukopheresis products obtained from patients included in a protocol interleukin-2/lymphokine-activated killer (IL-2/LAK) cell therapy, we analyzed, in parallel with the standard culture and on large volumes of these products, different parameters which could either improve LAK cell enhancement or simplify the procedure. We demonstrated first that purification of the mononuclear cells from the leukopheresis product before its culture is not required. An excess of red blood cells and granulocytes (up to 50%) in nonpurified samples improved both the mononuclear cell recovery in short-term culture (4 days) and the activation of LAK cells when the total nuclear cell concentration did not exceed 3 X 10(6)/ml. Different factors can contribute to this enhancing effect: the presence of red blood cells, the liberation of cytokines by granulocytes, or the loss of a population of activated lymphocytes, with liberation of cytokines by granulocytes, or the loss of a population of activated lymphocytes, with larger size and density than resting lymphocytes, during the separation. Supplementation of the medium with 2% heat-inactivated autologous plasma obtained before any treatment rather than with 2% pooled human AB serum does not modify the mononuclear cell recovery in 4-day culture, but it does enhance LAK activity. The inhibitory effect of heat-inactivated autologous plasma on proliferation and activation of LAK cells was never observed, suggesting the absence of suppressive factors in the plasma of the 23 analyzed patients. Similarly, autologous plasma did not modify natural killer and LAK cell functions when added during the cytotoxic assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗