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Biomedical subjects

D Colin

Publications and source records attributed to D Colin.

At least 37 records · Page 2Linked to original sources

Methods for quantitative analysis of trabecular bone structure.

Bone mineral density accounts for 70% to 80% of the mechanical resistance of bone but is unrelated to bone tissue structure. The vertebral fracture risk increases with advancing age irrespective of whether or not bone mineral density decreases, suggesting that changes in bone microarchitecture contribute significantly to the development of osteoporosis. In contrast to bone mass, bone architecture is difficult to evaluate. Among the various methods developed to investigate bone structure, biomechanical studies are of limited value since they are done on cadaver bones. Measurement of microarchitectural parameters (e.g., mean trabecular thickness, density and separation) in bone specimens obtained by needle biopsy is the gold-standard technique. Parameters reflecting trabecular interconnections (e.g., total number of nodes and free ends) can also be measured on needle biopsy specimens. New techniques of as yet unproven validity include star volume and trabecular bone pattern factor measurement. Noninvasive techniques capable of supplying qualitative information about bone tissue are also under study. Ultrasonography can theoretically provide data on bone microarchitecture but has not yet been proven useful in clinical practice. Statistical, structural, or fractal analysis techniques can be used to evaluate bone texture on digitized roentgenograms, computed tomography sections, or magnetic resonance imaging displays; although this approach holds great promise, it is still under evaluation and has not yet been compared with histomorphometry. Lastly, the apparent relaxation time of bone marrow determined using magnetic resonance imaging may also provide information on bone structure.

Biomechanical Phenomena

The "anatomic" view of the suprarenals in medical imaging.

Based on coordinates derived from three series of anatomic sections, the authors propose a view for tomographic investigation, applicable in MRI and ultrasound, which reconstructs the ideal image of the suprarenal gland in its quadrilateral as described by Testut. This "anatomic" view is 45 degrees vertical and oblique, intermediate between the sagittal and frontal views, which it can advantageously replace. A new aspect of suprarenal tomography, recalling the image of a triskele, is described in the context of this view.

Adrenal Glands

[Characteristics of fractures of the distal part of the clavicle in children].

Fractures of the clavicle are frequent in children and mostly affect the middle third. On the other hand, traumatic fractures of both medial and lateral thirds of the clavicle are rare. The lesions have special characteristics: difficulty in diagnosis for the medial third; risk of callus formation in the absence of surgical reduction of the lateral third. The authors report two observations of fractures of the medial and lateral thirds of the clavicle; they insist on the value of investigation by CT scan.

Child

Growth, carcass characteristics, and lipid composition of adipose tissue and muscle of pigs fed canola.

Sixty-one finishing pigs (53.4 kg) were fed a control diet (containing soybean meal) or diets containing 20% intact canola (IC) or 20% ground canola (GC) for 8 wk. Diets were not isocaloric. Daily gain and feed efficiency were not affected by dietary treatment, but pigs fed GC ate less than pigs fed either IC or the control diet. Carcass measurements, obtained on 43 of the pigs, were not affected by diet. For 27 pigs, fatty acid composition of perirenal adipose tissue (PRF), subcutaneous adipose tissue (SCF), and longissimus muscle (LDM) was analyzed. Nine pigs (three per treatment) were randomly selected for fatty acid composition analysis of intramuscular adipose tissue (IMF) and for cholesterol analysis of several tissues. Pigs fed canola had greater (P less than .05) proportions of mono- and polyunsaturated fatty acids and less (P less than .05) saturated fatty acids in PRF and SCF. The differences were more pronounced for PRF than for SCF. In the LDM, pigs fed canola tended to have elevated levels of unsaturated fatty acids at the expense of the saturated fatty acids, but this effect was significant for linolenic acid only. The fatty acid composition of IMF was not affected by diet (P greater than .05). Diet did not alter the cholesterol content of the tissues, but cholesterol in IMF was higher (P less than .05) than in PRF, SCF, and LDM. In conclusion, 20% IC or GC did not alter growth performance or carcass characteristics of pigs. Feeding of canola increased the degree of unsaturation of PRF and SCF, but it had less effect on IMF and LDM.

Adipose Tissue

[Techniques of autologous transfusion in hip surgery: a retrospective study].

A retrospective study was carried out on 99 patients undergoing hip surgery to evaluate the efficacy of three autotransfusion techniques on sparing of homologous blood. Preoperative normovolemic hemodilution (HDN), delayed autotransfusion (ATD) and recuperation of blood lost during surgery (RSPO) were studied. Patients were divided into 5 groups: group HDN, group ATD, group ATD + HDN, group RSPO, and the control group. The hematocrit was followed intra and postoperatively within these five groups, and mean values homologous blood transfusions calculated for each group. Comparison of mean values was performed using variance analysis (p less than 0.02). The association of delayed autotransfusion and preoperative hemodilution was most effective in sparing homologous blood (0.11 +/- 0.3 unit, p less than 0.02): however these results were obtained with a substantial drop in hematocrit which fell well below the 30% minimal accepted value at the end of the operation. There was no significant difference between delayed autotransfusion (0.35 +/- 0.8 unit) and preoperative hemodilution (0.7 +/- .01 unit) in sparing homologous blood. Hematocrit values with delayed autotransfusion were greater than these obtained with preoperative hemodilution. The difference was significant at the beginning of the operation (p less than 0.001), but not significant at the end. Recuperation of blood lost during surgery was least effective in sparing homologous blood (1 +/- 1.2 unit, p less than 0.02). Because of the moderate decrease in hematocrit, there are very few contraindications to delayed autotransfusion. Recuperation of blood lost during surgery should be associated with another autotransfusion technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

[3-dimensional reconstruction of x-ray computed tomographic views in fractures of the acetabulum].

In 21 cases of acetabulum fractures of 19 patients, the authors compare the findings given by three dimensional reconstructions of axial CT scan cuts with the plain films. The number of CT scan cuts is reasonable for each patient. Working time is about 20 to 30 minutes for the technician. In the cases of complex and displaced fractures, three dimensional imaging brings often decisive informations for the therapeutic management of these patients. Unusual views are often allowed but completely adapted to each type of fracture.

Acetabulum

Treatment of cutaneous candidosis in guinea pigs: effect of zinc oxide on the antifungal efficacy of nystatin.

This article describes the in vivo evaluation of a new topical preparation (Zincostatin) indicated for Candida albicans infected diaper rash. In order to study the influence of the 20% zinc oxide (W/W) (a protectant) on the anti-candidal efficacy of the 100,000 U/g of nystatin found in the ointment, groups of guinea pigs received different treatments with or without local occlusion. Zinc oxide, nystatin, or the combination of both were applied, in the ointment base, on the backs of the animals inoculated with a fresh strain of Candida albicans. Macroscopic and microbiological evaluation of the skin lesions were assessed at regular intervals during 21 days. While the two treatments containing nystatin were more effective than zinc oxide alone, the latter agent did not decrease the efficacy of the antifungal drug in combination therapy. Also, zinc oxide seemed to afford some protection against local maceration induced by occlusion, which increased the severity of the infection.

Animals

[The value of echography in the early diagnosis of renal lesions in the Laurence-Moon-Bardet-Biedl syndrome. Apropos of a case].

The Laurence-Moon-Bardet-Biedl syndrome (LMBB) is characterized by the association of obesity, hypogonadism, polydactyly, mental retardation and pigmentary retinitis. Symptomatic or asymptomatic renal dysplasia (calyceal diverticula, precalyceal tubular ectasia, cysts) is frequently associated with LMBB. The authors consider renal sonography as the convenient investigation for an early detection of such dysplasia as in the case they reported here.

Child

Reproduction study of toxaphene in the rat.

The purpose of the present study was to investigate in rats the reproductive effects of toxaphene, an insecticidal mixture which has been identified as a pollutant in the Great Lakes ecosystem. Groups of 30 female and 15 male weanling rats were given toxaphene in the diets at 0, 4.0, 20, 100 or 500 ppm in a 1 generation 2 litter reproduction study. Toxaphene treatment at the levels studied had no effects on the litter size, pup weight, fertility, or gestation and survival indices. Toxic effects in the parental rats included depressed weight gain, elevated serum cholesterol, and increased liver and kidney weight and hepatic microsomal enzyme activities. Most of these effects were associated only with 500 ppm toxaphene treatment. Treatment-related histological changes in the liver, thyroid and kidney of adult rats were observed at levels as low as 20 ppm. Based on the data presented, the no observable adverse effect dose of toxaphene was considered to be 4.0 ppm in the diet (0.29-0.38 mg/kg b.w./day depending on the amount of dietary intake).

Aminopyrine N-Demethylase