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Biomedical subjects

C Normand

Publications and source records attributed to C Normand.

At least 73 records · Page 4Linked to original sources
PubMed1986

Long-term maintenance of hepatocyte functional activity in co-culture: requirements for sinusoidal endothelial cells and dexamethasone.

Sinusoidal cells isolated from adult rat liver have been established in primary culture and in cell line. The presence of factor VIII R:Ag and peroxidatic/phagocytosis activities were the criteria used to distinguish in freshly isolated cells the endothelial cells from the Kupffer cells and suggested the endothelial origin of the cell line. Using a co-culture system, the effect of sinusoidal liver cells on hepatocyte functional activity was characterized. A plateau in which the state of differentiation was stabilized could be generated for co-cultured hepatocytes isolated from adult rat and a disappearance of the initial expression of alpha 1-fetoprotein (AFP) and the increase and/or maintenance of albumin secretion were measured with co-cultured hepatocytes isolated from suckling rat. The presence of dexamethasone was required for such beneficial effect. The hepatocyte-stabilizing activity was also produced by a pulmonary endothelial cell line.

Cell Communication↗
PubMed1986

Tumor-like massive thymic hyperplasia in childhood: a possible defect of T-cell maturation, histological and cytoenzymatic studies of three cases.

Contrary to the transitory, enlarged thymic shadow commonly observed in babies, tumor-like Massive Thymic Hyperplasia (MTH) is seldom encountered in infancy and even more rarely in children over 4 years. We present three cases of MTH affecting 10, 5 and 11 years old girls in whom the tremendous enlargement of the thymus (3 to 4 times the normal) led to consideration of a diagnosis of a genuine tumoral process and to either biopsy or surgical removal of the thymic mass. Optical histological examination showed a perfectly normal thymic tissue and indicated that MTH was linked with a simple and homogeneous hyperplasia of the lymphoid cells. Using the dot-like acid alpha-naphtyl acetate esterase (ANAE) as a marker of mature T cells, quantitative and comparative cytoenzymatic studies revealed a definite reduction of ANAE +, mature T cells in the cortical and medullary areas in MTH (p less than or equal to 0.001). These findings suggest that MTH represents an intrathymic accumulation of immature T cells, a condition which may express a failure of cell differentiation perhaps connected with some thymic hormonal insufficiency.

Cell Differentiation↗
PubMed1980

Action of intensive cigarette smoke inhalations on the rat lung. Role of particulate and gaseous cofactors.

The action of high doses of cigarette smoke alone or combined with coal dust or acrolein was investigated in noninbred Sprague-Dawley rats. Inhalation occurred up to six sessions per day (Hamburg machine), the animals being subjected to a treatment with oxygen after each inhalation session to reduce the carbon monoxide level in the blood. The amount of tar found in the lungs depended on the number of inhalation sessions per day rather than on the total number of inhalations. Smoke inhalation caused emphysematous lesions, the extent of which depended on the total dose of smoke inhaled. No lung tumors were observed. Only a hyperplasia of the alveolar lining involving type II alveolar cells and, at a later stage, areas of metaplasia generally limited to the bronchial area were found. The association of coal dust with cigarette smoke did not alter the specific effects of smoke and resulted in effects peculiar to the action of dust: alveolitis of the macrophage type, fibrosis of the reticulin type, limited hyperplasia, and ciliated metaplasia. When smoke was combined with acrolein, the effects due to smoke were not appreciably altered.

Acrolein↗
PubMed1967

Correlations of mechanical stability, morphology, pulmonary surfactant, and phospholipid content in the developing lamb lung.

Pressure-volume characteristics and surface tension measurements of the lamb of 120 to 130 days gestational age were typical of the mature lung in the upper lobes and the immature lung in the lower lobes. By term both upper and lower lobes had findings characteristic of the mature animal. Phospholipid concentration per milligram DNA and per cent saturated fatty acids on pulmonary phosphatidyl choline were relatively constant from 60 to 120 days gestational age; thereafter there was a significant increase in both measurements. These changes usually coincided with an increase in osmiophilic inclusion bodies in the large alveolar cell.A concentration of disaturated phosphatidyl choline per milligram DNA in excess of 0.170 mg per mg was associated with a minimal surface tension below 13 dynes per cm (p < 0.001). Newborn animal lungs contained over 3 times this critical concentration, whereas adult lungs contained 1.5 times this value. The excess disaturated phosphatidyl choline per milligram DNA may represent a reservoir of pulmonary surfactant.

Animals↗
PubMedDate not supplied

Costing neonatal care alongside the Collaborative ECMO trial: how much primary research is required?

Researchers working on economic evaluations alongside trials have to balance minimising data collection with maximising the ability to measure differences in costs. Using existing data sources may keep the costs of research down, but these data may not be entirely appropriate to the evaluation question. When evaluating technologies in intensive care it is particularly important to be able to classify patients correctly by their resource requirements especially when those requirements vary considerably from day to day. This paper describes and justifies methods for costing the care provided for babies in (one arm of) an on-going multi-centre trial, the Collaborative ECMO trial. This trial is evaluating alternative policies of life support for mature (full term) newborn babies with severe respiratory failure. The most reliable cost information on neonatal intensive care is available from a study, conducted independently from the trial, which has used simple cost apportionment on a large sample of units. By drawing on clinical opinion and carrying out a case note exercise we assessed whether this available information was appropriate to estimate 'baseline' costs for the control group during their initial 'acute' phase of illness. We concluded that the available cost estimates would need to be weighted to reflect the additional costs of drugs and investigations for this group of babies during the acute phase. Multidisciplinary collaboration on trials can help economists and other researchers to balance the requirement for simple cost measurements with more detailed primary research.

Cost-Benefit Analysis↗
PubMedDate not supplied

Cellular interactions promote tissue-specific function, biomatrix deposition and junctional communication of primary cultured hepatocytes.

Hepatocytes, prepared from normal adult rat liver, were seeded onto a collagen substratum and cultured alone or in the presence of rat liver endothelial cells. When hepatocytes were cultured alone in a hormonally defined serum-free medium, decreased albumin production and rapid morphological deterioration of bile canaliculi structures and gap junctions occurred within 4 to 5 days. In contrast, hepatocytes cocultured with liver mesenchymal cells remained morphologically intact and biochemically functional for at least 4 weeks. They reorganized into small islands, continued to secrete high levels of albumin, did not express alpha-fetoprotein (a fetal marker), and remained strongly dye coupled. All of the hepatocytes synthesized albumin and retained their gap junctional channels. No junctional communication was observed between hepatocytes and endothelial cells. Long fibers containing fibronectin, Type I collagen and laminin distributed over the hepatocytes were induced in coculture but never appeared in hepatocytes cultured alone. Moreover, supplementation of the hormonally defined medium with phenobarbital and dimethyl sulfoxide, both of which improve the life span and functional activities of cultured hepatocytes, failed to induce reticulin fiber formation in pure culture of hepatocytes. The modulation of albumin secretion, biomatrix deposition and junctional communication observed in hepatocytes cultured with sinusoidal liver cells was also obtained when hepatocytes were in association with various epithelial or mesenchymal cells [rat liver epithelial cells (T51B), mouse embryonic fibroblasts (NIH 3T3), human or rat dermal fibroblasts and bovine aorta endothelial cells (AG 4762)].

Albumins↗