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Biomedical subjects

C Girard

Publications and source records attributed to C Girard.

At least 19 recordsLinked to original sources
PubMed1992

[3H]muscimol and [3H]flunitrazepam binding sites in the developing cerebellum of mice treated with methylazoxymethanol at different postnatal ages.

Two models of perturbed cerebellar ontogenesis were obtained by a single administration of methylazoxymethanol (MAM), a potent antimitotic agent, to mouse pups either on the day of birth (MAM0 mice) or at postnatal day 5 (MAM5 mice). The alterations of the cerebellar GABAergic system were studied by measuring glutamic acid decarboxylase activity, [3H]muscimol binding sites, which are known to be concentrated in the GABAA receptors in the internal granular layer, and [3H]flunitrazepam binding sites, which are more abundant in the molecular layer. The primary target of the antimitotic agent are the precursors of the glutamatergic and GABAceptive granule cells. In both models GABAergic structures, as revealed by GAD activity measurements, appear to be relatively spared, and recovery of granule cell numbers occurs during development in MAM5 mice. In MAM treated mice the number of [3H]muscimol binding sites (on a per cerebellum basis) decrease as the number of granule cells decrease, although some recovery occurred in MAM5 mice, but not in MAM0 mice. In MAM5 mice, [3H]flunitrazepam binding sites (on a per cerebellum basis) were relatively unaffected, while they were decreased significantly, but to a lesser extent than [3H]muscimol binding sites, in MAM0 animals. The more significant reduction of granule cell numbers and the cytoarchitectural disruption resultant from the more precocious application of the antimitotic appear responsible for the significant alteration and lack of recovery in MAM0 mice.

Animals↗
PubMed1992

Portable image-manipulation software: what is the extra development cost?

A hospital-wide picture archiving and communication system (PACS) project is currently under development at the University Hospital of Geneva. The visualization and manipulation of images provided by different imaging modalities constitutes one of the most challenging component of a PACS. It was necessary to provide this visualization software on a number of types of workstations because of the varying requirements imposed by the range of clinical uses it must serve. The user interface must be the same, independent of the underlying workstation. In addition to a standard set of image-manipulation and processing tools, there is a need for more specific clinical tools that can be easily adapted to specific medical requirements. To achieve this goal, it was elected to develop a modular and portable software called OSIRIS. This software is available on two different operating systems (the UNIX standard X-11/OSF-Motif based workstations and the Macintosh family) and can be easily ported to other systems. The extra effort required to design such software in a modular and portable way was worthwhile because it resulted in a platform that can be easily expanded and adapted to a variety of specific clinical applications. Its portability allows users to benefit from the rapidly evolving workstation technology and to adapt the performance to suit their needs.

Costs and Cost Analysis↗
PubMed1992

Glucose and insulin supply before cardiopulmonary bypass in cardiac surgery: a double-blind study.

A double-blind study versus placebo was carried out to evaluate the effects of a 500-mL infusion of 30% glucose containing 300 units of ordinary insulin and 5 g of potassium chloride administered at a rate of 1.66 mL.kg-1.h-1 for 1 hour before cardiopulmonary bypass. The hemodynamic parameters measured before and after administration of the solution, after cardiopulmonary bypass, after administration of protamine, and 3 hours after leaving the operating room showed the beneficial effect of the glucose-insulin-potassium infusion on cardiac index (+23.6% after protamine infusion) and left (+16.3% 3 hours postoperatively) and right (+47.3% after cardiopulmonary bypass) ventricular workload index with a decrease in systemic vascular resistance. For patients with a cardiac index of less than 2.5 L.min-1.m-2 before administration of the glucose-insulin-potassium solution, the beneficial effect on the cardiac index was further increased 3 hours postoperatively (+33%). During the postoperative period, the requirements in inotropic drugs and disturbances of rhythm were not significantly different between the two groups, although they were twofold lower in patients receiving glucose-insulin-potassium. Laboratory tests showed that postoperative hypoglycemia was more common in the glucose-insulin-potassium group but had no detrimental effects; it no longer occurs since we began administering the glucose infusion at 15 g/h over 8 hours. The data reflect the beneficial effect associated with the action of glucose-insulin-potassium on myocardial protection during heart operations and were confirmed by the hemodynamic results. This argues in favor of the routine use of this technique, especially in patients with poor ventricular function.

Cardiac Surgical Procedures↗
PubMed1992

Effect of age and intake on growth hormone kinetics in dairy heifers.

The effects of aging and intake on growth hormone (GH) kinetics and GH-releasing factor (GRF)-induced GH concentrations were studied in two groups of 12 Holstein heifers each (80 d, 85 kg: young; and 273 d of age, 246 kg: old). Each group was then equally subdivided into full-fed (FF) and restricted-fed (RF) subgroups. After 11 d of intake treatment, animals were infused for 3 hr with GH (1.5 mg/hr) in order to calculate GH metabolic clearance rate (MCR), secretion rate (SR) and half-life (t 1/2). Two d later, total plasma volume was determined and the following day, all heifers received a GRF challenge (5 micrograms/kg i.v.). The following values are LSM +/- SE for young-FF, young-RF, old-FF and old-RF. Rate of secretion was not affected by any treatment, averaging 1.51, 1.25, 1.34, and 1.40 +/- .23 micrograms/min. Aging increased (P < .01) MCR (186, 159, 382, and 300 +/- 21 ml/min) and increased plasma volume (P < .01), which resulted in lower basal GH concentrations. Aging also decreased (P < .01) the area under the GH response curve following GRF injection (AUC: 12442, 21114, 5155, and 6308 +/- 1776 ng.min/ml) but did not affect average GH quantity in the plasma after the GRF challenge. Feed restriction decreased (P < .05) MCR, but not enough to affect basal GH concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Reduction in blood loss and blood use after cardiopulmonary bypass with high-dose aprotinin versus autologous fresh whole blood transfusion.

Ninety patients undergoing cardiac surgery were randomly divided into three groups of 30 patients to compare the effects on bleeding and transfusion requirements of either intraoperative infusion of high-dose aprotinin (GpI) or reinfusion of autologous fresh whole blood (GpII) versus a control group (GpIII). Standardized anesthetic, perfusion, and surgical techniques were used. Platelet counts, hemoglobin concentration, hematocrit, fibrinogen, and Ivy-Nelson bleeding times determined at fixed times perioperatively did not differ among the three groups. The total loss from the chest drains was significantly reduced in GpI (328 +/- 28 mL; mean +/- SEM) as compared with the loss in GpII and GpIII (775 +/- 75 mL and 834 +/- 68 mL, respectively). There was a threefold difference in the total hemoglobin loss (GpI, 14.2 +/- 1.7 g; GpII, 50.1 +/- 5.0 g; GpIII, 45.0 +/- 5.2 g). GpI patients also received less banked blood: 250 +/- 53 mL versus 507 +/- 95 mL in GpII and 557 +/- 75 mL in GpIII. No GpI patient required transfusion of platelets or fresh frozen plasma. Fresh whole autologous blood transfusions had no significant hemostatic effect and failed to reduce the homologous blood requirement. Conversely, high-dose aprotinin reduced blood loss and transfusion requirements.

Adult↗
PubMed1992

Inhaled nitric oxide after mitral valve replacement in patients with chronic pulmonary artery hypertension.

Patients with mitral valve disease can develop pulmonary artery hypertension that persists after mitral valve replacement. In 1987, nitric oxide (NO) was reported to be an important factor accounting for the biologic activity of endothelium-derived relaxing factor. Inhaled NO was subsequently reported to be a selective pulmonary vasodilator in animals and patients. Therefore we investigated the vasodilating effect of inhaled NO in patients with mild pulmonary artery hypertension after mitral valve replacement. Six patients who underwent mitral valve replacement for mitral stenosis presented with a mean pulmonary artery pressure greater than 25 mmHg within 24 h after surgery. During mechanical ventilation at FIO2 0.5, NO (36.8-38.4 ppm) was breathed for 10 min. Hemodynamic data were recorded before NO, after 10 min of NO inhalation, and 30 min after the end of NO inhalation. Statistically significant (P < 0.05) hemodynamic response to inhaled NO included a transient decrease in systolic (-10%), diastolic (-8%), and mean (-10%) pulmonary artery pressures; a decrease in pulmonary vascular resistance (-22%); an increase in mixed venous hemoglobin O2 saturation (+6%); and a decrease in arteriovenous O2 content difference (-7%). During NO inhalation, there was no change in systemic arterial or pulmonary wedge pressures. Methemoglobin levels remained < 1%. Inhalation of this concentration of NO for 10 min causes transient pulmonary artery vasodilation and hemodynamic improvement in patients with mild chronic pulmonary artery hypertension after mitral valve replacement.

Administration, Inhalation↗
PubMed1992

Ectopic granule cells in mouse cerebellum molecular layer express high affinity GABAA receptor.

The antimitotic/mutagenic agent methylazoxymethanol when injected in mice pups at postnatal days 3 and 4 produces hypogranular adult cerebella with subpial cells clusters and with a supplementary, ectopic granule cells layer in the molecular layer. The internal granular layer of these treated mice displayed a much lower density of [3H]muscimol binding sites than in controls. At the same time these binding sites are expressed in the ectopic granule cells in the middle of the molecular layer, in spite of the unusual localization of the cells and of the alteration of their nerve inputs. The subpial cells do not express these sites. Our autoradiographic data confirm the suggestion that during ontogeny the GABAA receptors in the granule cells appear when these cells leave the subpial region and indicate that the expressed receptor subtype is the same whether granule cells are in the internal granular layer or in the middle of the molecular layer.

Animals↗
PubMed1992

Single lung transplantation for primary pulmonary hypertension without cardiopulmonary bypass.

We report the first case, to our knowledge, of single lung transplantation for primary pulmonary hypertension carried out without cardiopulmonary bypass. This operation seems to be possible even if the right ventricular ejection fraction is low (0.17) and the pulmonary vascular resistance very high (1,096 dynes.s.cm5). Since 1981, heart-lung transplantation has been successfully performed in patients with primary pulmonary hypertension. If heart-lung transplantation results in resolution of pulmonary hypertension, the incidence of obliterative bronchiolitis is significant in heart-lung transplantation recipients. Single lung transplantation has been performed for end-stage interstitial and obstructive lung disease but has not been considered a good option for primary pulmonary hypertension due to concerns that a single transplanted lung would be unable to cope with the entire blood flow. However, recently single lung transplantation has been performed for primary pulmonary hypertension, the risk of obliterative bronchiolitis remaining unknown. The purpose of this communication is to report one case of single lung transplantation for primary pulmonary hypertension and the feasibility of this operation without the use of cardiopulmonary bypass, if cardiopulmonary bypass is thought to be dangerous.

Adult↗
PubMed1992

In vitro colonization of porcine trachea by Mycoplasma hyopneumoniae.

Porcine tracheae maintained in culture were used in order to study the colonization by Mycoplasma hyopneumoniae. Rings excised from tracheae of newborn piglets were infected with M hyopneumoniae strain BQ 14 and, after different incubation times, were examined by light and electron microscopy. Non-infected tracheal mucosae maintained a normal appearance for several days. Infected tracheal rings showed progressive colonization with concomitant progressive damage to the mucosal surface. Early on during the infection, few mycoplasmas occurred over a ciliated epithelium. As the infection progressed, there was gradual loss of cilia; mycoplasmas tended to form microcolonies and to accumulate over the remaining ciliated cells. Mycoplasmas, first seen at the apex of the cilia, were then seen deeper in the inter-ciliary space; some were even seen in contact with microvilli. In histological investigation, the final stage of the infection was characterized by a marked destruction of the epithelium with exfoliation of the epithelial cells. Infected mucosae showed typical damage caused by M hyopneumoniae, namely reduction of ciliary activity after 5 days, loss of cilia, and sloughing of ciliated cells. Our data indicate that porcine tracheal organ culture can be advantageously used to study colonization by M hyopneumoniae.

Animals↗
PubMed1992

Physician satisfaction in a managed care environment.

BACKGROUND: The professional literature suggests that changes toward the bureaucratization of medical practice have led to increasing job dissatisfaction, especially in primary care. To investigate this claim, we surveyed physicians in Dane County, Wisconsin, who practice in a bureaucratic setting. Dane County has experienced essentially a demise in independent practice, ie, most physicians practice in organizational settings where expenses and total patient income are pooled. About 85% of physicians have joined one of the six competing health maintenance organizations (HMOs). METHODS: In 1986 all 850 physicians in Dane County were surveyed to determine their perceptions of clinical freedom, satisfaction with income, status in their profession, autonomy, resources, and professional relations, and their overall satisfaction. RESULTS: We found that over 69% of primary care physicians were very satisfied or satisfied with their practices overall compared with 68% of physicians in all specialties. Differences between family practice and other primary care specialties were not statistically significant. Our regression analysis showed that only for satisfaction with income were responses from primary care physicians significantly different from those of physicians in surgical specialties. Perceptions of clinical autonomy and specific organizational settings were more important to predicting satisfaction. Also, age and sex contributed to differences in satisfaction with resources and status, respectively. CONCLUSIONS: We conclude that satisfaction can be fairly high for primary care physicians in bureaucratic settings similar to that of Dane County.

Group Practice↗
PubMed1991

Ectopic granule cell layer in mouse cerebellum after methyl-azoxy-methanol (MAM) treatment.

Previous results from our laboratory (Bejar et al. 1985) indicated that a single injection in mouse pups of the antimitotic/mutagenic agent methylazoxymethanol at postnatal day 5 typically produces hypogranular cerebella with no changes in foliation, in contrast to the severe alterations observed after the more usual injection on the day of birth. Here we report that injection of a higher dose (30 mg/kg) of methylazoxymethanol, always at postnatal day 5, leads to the additional presence of a ectopic cell layer in adult cerebellum. Immunostaining with several antibodies recognizing cell specific proteins ruled out the possibility that these ectopic cells were glial and electron microscopy indicated that they were morphologically mature granule cells. In the molecular layer of other cerebellar areas and apparently unrelated with granule cell ectopia, ectopic Golgi epithelial cells were observed. The reason for the presence of these ectopic cells of different type in the molecular layer was discussed in relation with analogous ectopias obtained by other means.

Animals↗
PubMed1991

Autoradiographic characterization of [3H]L-glutamate binding sites in developing mouse cerebellar cortex.

Postnatal changes of [3H]L-glutamate binding sites in mouse cerebellum were studied by in vitro autoradiography. These sites were already present at birth, their density globally increased until postnatal day 25, and at all ages it was higher when Cl- and Ca2+ were present in the incubation buffer. At birth, these binding sites were diffused through the whole cerebellar mass, but became distinctly concentrated in the molecular and the internal granular layers by postnatal day 10. From this age on, binding site sensitivity to ions and glutamate analogues takes a different course in each layer. The external granular layer and the white matter never displayed significant amounts of binding. In the molecular layer the Cl-/Ca2+ effect increased during ontogeny until, in adults, the ion-dependent binding was threefold higher than the ion-independent binding. Quisqualate-sensitive sites accounted for 80% of the total binding sites already at postnatal day 15, while displacement by alpha-amino-3-hydroxy-methyl-4-isoxazolepropionic and ibotenic acids attained the maximum (68%) at postnatal day 60. N-Methyl-D-aspartate displaced glutamate binding (50%) only in the presence of Cl- and Ca2+. Starting from postnatal day 15, binding site density in the molecular layer of lobules VIb and VII of the vermis was lower than in other lobules. In the internal granular layer, the Cl-/Ca2+ effect observed in young animals decreased during development. These transient binding sites were sensitive to quisqualic and ibotenic acid. In adults, the majority of glutamate binding sites were ion-independent and mainly sensitive to D,L-amino-5-phospho-valeric acid and N-methyl-D-aspartate. Throughout development and in both layers, sites displaced by kainate were present at low density and sites displaced by D,L-2-amino-4-phosphonobutyric acid were not detected. The localized postnatal changes of the [3H]L-glutamate binding sites were correlated with the events occurring during growth and maturation of cerebellar structures. The increase of the Cl-/Ca(2+)-dependent binding in the molecular layer is simultaneous with the growth of Purkinje cell dendrites and of parallel fibres and with the formation of the synapses between them. This suggests that these binding sites are localized in these synapses. The changing pattern of sensitivity to different agonists during development might correspond to the maturation of these synapses. The low density of [3H]L-glutamate binding in the molecular layer of lobules VIb and VII probably indicates the presence of specific nerve projections to these areas.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗