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Biomedical subjects

C Bernard

Publications and source records attributed to C Bernard.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

Blockade of bombesin receptors with [Leu14-psi(CH2NH)-Leu13]bombesin fails to suppress nutrient-induced CCK release from rat duodenojejunum.

The present study was undertaken in order to delineate the contribution of enteric bombesin (BBS)-containing nerves in the food-induced release of intestinal cholecystokinin (CCK). For this purpose, the isolated vascularly perfused rat duodenojejunum model was used and the new compound [Leu14-psi(CH2NH)-Leu13]BBS was infused intraarterially at a concentration of 10(-6) M to block the BBS receptors. Vascular infusion of BBS alone (10(-8) M or 10(-9) M) provoked a dose-dependent release of CCK-like immunoreactivity (CCK-LI). The secretion pattern of CCK was biphasic and consisted of a transient peak (300-400% above basal) followed by a sustained response (200-300% above basal). Vascular coinfusion of the BBS analogue with BBS 10(-9) M completely abolished both phases of CCK release while only the second phase of CCK secretion was profoundly reduced upon coadministration of BBS 10(-8) M with the BBS receptor antagonist. Luminal administration of mixed nutrients induced a prompt and well-sustained release of CCK-LI which was unaffected upon arterial infusion of the BBS analogue. These data suggest that the intestinal supply in BBS-producing nerves is not involved in the food-induced release of intestinal CCK in the rat.

Animals↗
PubMedDate not supplied

Role of calcium in the bombesin-induced intestinal CCK release in rats.

In the isolated vascularly perfused rat duodenojejunum, vascular infusion of bombesin (100 nM) provoked an early, transient (6 min) release of CCK (500% of basal), followed by a sustained response (400% of basal). The calcium chelator EGTA (2 mM) reduced the early peak and abolished the second phase of CCK release. A similar variation was evoked by verapamil (10 microM), whereas diltiazem (100 microM), nifedipine (50 microM), and omega-conotoxin (100 nM) had no significant effect. It is concluded that bombesin-induced CCK release from rat intestine is dependent on the availability of extracellular calcium and on the activation of calcium channels sensitive to blockers of the phenylalkylamine family.

Animals↗
PubMedDate not supplied

Immunological relationship among glyceraldehyde-3-phosphate dehydrogenases in the genera Enterobacter and Escherichia.

The comparative immunological study of glyceraldehyde-3-phosphate dehydrogenase (G-3-PDH) among Enterobacteriaceae carried out with an anti-Enterobacter cloacae G-3-PDH serum pointed out the large heterogeneity of the genera Enterobacter and Escherichia. The use of two-dimensional maps integrating our new data and previously acquired quantitative data confirmed these results.

Enterobacter↗
PubMedDate not supplied

Effect of total parenteral nutrition, constant rate enteral nutrition, and discontinuous oral feeding on plasma cholecystokinin immunoreactivity in children.

Plasma cholecystokinin (CCK) levels were measured by radioimmunoassay in 100 children (mean age: 20 months) on various types of artificial nutrition. Of the 81 children given total parenteral nutrition (TPN), 32 were studied while on cyclic TPN (cTPN), 66 while on partial fractioned feeding completed by parenteral nutrition, 25 while on constant rate enteral nutrition, and 18 while on total discontinuous oral feeding. The remaining 19 control cases were on normal alimentation. Plasma CCK levels during TPN (21.4 +/- 1.6 pg/ml), cTPN (21.8 +/- 2.7 pg/ml), and constant rate enteral nutrition (26.4 +/- 2.8 pg/ml) were not significantly different from each other and were similar to preprandial total discontinuous feeding (21 +/- 2 pg/ml) and control (22.6 +/- 3.5 pg/ml) levels. The postprandial CCK level increased significantly in partial fractionated feeding (33.6 +/- 3.3 pg/ml, p less than 0.02) but remained half that of postprandial total discontinuous oral feeding (75.6 +/- 6.6 pg/ml, p less than 0.001) and postprandial controls (75 +/- 7 pg/ml, p less than 0.001). Thus, basal and stimulated CCK levels are similar in children and adults, and the use of long-term artificial nutritional techniques does not modify the feeding stimulation of CCK. Plasma CCK levels during TPN and constant rate enteral nutrition are similar to fasting values, indicating a possible role for CCK in the biliary sludge.

Child, Preschool↗
PubMedDate not supplied

Control of Candida albicans vaginitis in mice by short-duration butoconazole treatment in situ.

A short-duration treatment for candidal vaginitis applying butoconazole in situ was tested in an experimental mouse model. One week after artificial induction of an oestrus state (by oestradiol benzoate injection), mice were inoculated intravaginally with 1.5 x 10(7) blastospores of Candida albicans (strain ATCC 44858). Treatment consisted of butoconazole solutions (1%, 2.5% and 5%) administered intravaginally. The development of the infection was monitored daily for 12 days and then three times a week by local samples plated on BiGGY agar. In parallel, twice a week, the vaginas of three mice in each group (control and treated groups) were isolated in order to estimate organ invasion by C. albicans. This was assessed by anatomopathological studies on a fixed and stained part of the organ and by serial dilutions of a homogenate of the remaining part plated on Sabouraud glucose chloramphenicol agar. After a 48-h incubation period the number of colony forming units per gram of tissue was counted. For each treatment, a remission of 10-15 days was observed, but was followed by a recurrence for the lower dose of butoconazole; only the higher butoconazole concentrations tested (2.5% and 5%) gave an apparent full cure for most of the mice tested. The use of the mouse model of candidal vaginitis confirms that short-duration treatment is possible when elevated doses of butoconazole are used.

Animals↗
PubMedDate not supplied

Pericardial hemangioma presenting as thoracic mass in utero.

Pericardial hemangiomas are rare lesions. We present the case of an infant who was referred to our fetal diagnosis and treatment group for the presence of a left thoracic mass, pleural effusion, and mediastinal shift on fetal ultrasound. The characteristics of the lesion suggested the presence of a pulmonary sequestration. A chest radiograph done at birth was normal. At 2 weeks of age, an enhancing lesion of the left pericardium was identified on chest CT. A cardiac MRI demonstrated enhancement of the mass on T2-weighted images. The patient underwent thoracoscopic assessment of the mass for diagnostic purposes. Multiple lesions were identified along the left pericardium and diaphragm. A frozen section biopsy revealed a hemangioma. The natural history for hemangiomas is gradual regression; however, they may increase acutely in size and cause symptoms prior to involution. Investigations should be performed to identify the involvement of other organs. This case illustrates the need to closely follow all patients with prenatally diagnosed thoracic masses with CT imaging, even when they are asymptomatic and have a normal chest radiograph at birth.

Adult↗
PubMedDate not supplied

Rapid effect of LPS-activated macrophages on the reactivity of the rat mesenteric artery.

This study was designed to evaluate the effects of lipopolysaccharide (LPS)-activated macrophages in the perfused mesenteric circulation of the rat. The mesenteric network of anesthetized rats was perfused in situ under constant flow conditions and the diameter and pressure of the mesenteric artery were continuously recorded. For the first 30 min the mesenteric network was perfused with an RPMI solution (control condition); thereafter it was perfused for 60 min with the same solution containing either (1) LPS (1 microgram/ml), (2) elicited macrophages (10(6) cells/ml), (3) LPS-activated macrophages or (4) supernatants derived from LPS-activated macrophages (SPN). The changes in arterial diameter induced by topical application of phenylephrine (PE, 10 mumol/l) were measured under control conditions and then 30 and 60 min after the onset of perfusions. The intravascular pressure was similarly increased (51 +/- 6%, p < 0.001) by the perfusion of activated macrophages or elicited macrophages but was not affected by perfusion of LPS or SPN. Despite the same level of transmural mesenteric pressure in rats perfused with activated and elicited macrophages, the mesenteric diameter was significantly larger with activated than with elicited macrophages (p < 0.05). Under control conditions, PE induced a marked decrease in arterial diameter from 495 +/- 15 to 265 +/- 13 microns (p < 0.001). Perfusion of LPS, elicited macrophages or SPN did not modify the vascular reactivity to PE. Perfusion of activated macrophages reduced the PE-induced contraction by 77 +/- 6% (p < 0.001). Perfusion of elicited macrophages with a nitric oxide (NO) donor (SIN-1, 10 mumol/l) reproduced the effect of LPS-activated macrophages while addition of an NO scavenger (oxyhemoglobin, 10 mumol/l) prevented the depression of the vascular reactivity to PE by activated macrophages. Finally, activated macrophages preincubated with an inhibitor of NO synthesis (NG-monomethyl-L-arginine); L-NMMA), and then perfused in RPMI solution without L-NMMA had no effect on the PE reactivity of the mesenteric artery suggesting that NO released by activated macrophages directly and rapidly inhibited the contractility of the mesenteric artery. The results of this study demonstrate the opposing effects of macrophages in the mesenteric circulation to increase microvascular resistance by a rheological effect while decreasing the reactivity of the mesenteric artery as a result of NO released by macrophages.

Animals↗
PubMedDate not supplied

Oncostatin M induces interleukin-6 and cyclooxygenase-2 expression in human vascular smooth muscle cells : synergy with interleukin-1beta.

Oncostatin M (OSM), a cytokine first identified from activated monocytes and T lymphocytes, is one of the most potent autocrine growth factor for AIDS and Kaposi's sarcoma. Little is known about the effects of OSM on normal vascular cells. We thus exposed human aortic smooth muscle cells (hASMCs) to OSM, examined cell proliferation and morphology, and determined interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) expression. OSM had a weak antiproliferative effect. After a 4-day incubation with 100 ng/mL OSM, cell count decreased to 69+/-3% of control. However, OSM induced striking changes in hASMC morphology, characterized by a polyclonal shape, in contrast to the spindle morphological feature of control hASMCs. OSM stimulated the release of IL-6 by hASMCs in a dose-dependent way; after a 48-hour exposure, values were 8.5+/-0.7, 29.7+/-3.5, 50.9+/-4.4, and 73.8+/-7.6x10(3) U/mL (n=6) at OSM concentrations of 0, 1, 10, and 100 ng/mL, respectively. OSM induced marked expression of COX-2 protein and mRNA. Leukemia inhibitory factor had no effect on hASMCs, indicating that OSM effects on hASMCs were mediated by the OSM type II receptor and not by the leukemia inhibitory factor receptor. OSM used the JAK/STAT signaling pathway, as demonstrated by rapid phosphorylation of JAK1 and specific activation of STAT1. Interestingly, OSM acted in synergy with IL-1beta on IL-6 production and COX-2 expression. In conclusion, OSM is a novel regulator of human smooth muscle cell functions, acting in concert with IL-1beta, and OSM may play a role in major vascular diseases such as atherosclerosis.

Cells, Cultured↗
PubMedDate not supplied

Action of streptomycin and calcium on the apical membrane of hair cells of the frog isolated semicircular canal.

An isolated frog posterior semicircular canal was placed in a two-compartment perspex chamber allowing separate perfusions of the peri- and endolymphatic space with adequate saline solutions. The ampullar receptors were mechanically stimulated with a hydraulic device which imposed sinusoidal movements to the cupulo-endolymphatic system at low frequency (0.10 Hz). Slow potentials recorded with non-polarizable Ag/AgCl electrodes near the crista ampullaris (Adc) and on the ampullar nerve (Ndc) were displayed together with an analog signal of the mechanical stimulation and with the nerve spike frequency, on a strip chart. The streptomycin action or the high calcium concentration action (these two substances being administered together or separately into the ampullar space) indicated that the streptomycin seemed to block mechano-dependent channels (non-specific) assumed to be included into the hair cell apical membrane. The synaptic transmission process was altered by streptomycin but was improved by the high calcium concentration. Also, the mechanisms which would control the spontaneous release of a neurotransmitter, seemed, at least partly, different from those controlling the neurotransmitter release in response to a mechanical stimulation; these last ones were less sensitive to the calcium action.

Action Potentials↗
PubMedDate not supplied

Modelling the arterial wall by finite elements.

The mechanical behaviour of the arterial wall was determined theoretically utilizing some parameters of blood flow measured in vivo. Continuous experimental measurements of pressure and diameter were recorded in anesthetized dogs on the thoracic ascending and midabdominal aorta. The pressure was measured by using a catheter, and the diameter firstly, at the same site, by a plethysmograph with mercury gauge and secondly, by a sonomicrometer with ferroelectric ceramic transducers. The unstressed radius and thickness were measured at the end of each experiment in situ. Considering that the viscous component is not important relatively to the nonlinear component of the elasticity and utilizing several equations for Young modulus calculation (thick and thin wall circular cylindrical tube formulas and Bergel's equation) the following values were obtained for this parameter: 0.6 MPa-2 MPa in midabdominal aorta and 2 MPa-6.5 MPa in thoracic ascending aorta. The behaviour of the aorta wall was modelled considering an elastic law and using the finite element program "Lagamine" working in large deformations. The discretized equilibrium equations are non-linear and a unique axi-symmetric, iso-parametric element of 1 cm in length with 8 knots was used for this bi-dimensional problem. The theoretical estimation of radius vessel, utilizing a constant 5 MPa Young modulus and also a variable one, are in good agreement with the experimental results, showing that this finite element model can be applied to study mechanical properties of the arteries in physiological and pathological conditions.

Animals↗
PubMedDate not supplied

[Iliac crest bone CO2 and CO2/Ca ratio in man during respiratory failure (author's transl)].

The bone is often considered as a slow exchanger and bone sampling from the iliac crest, by needle-biopsy, is a commonly used and atraumatic technique; therefore the significance of the evolution of CO2 stores has been investigated in iliac crest in respiratory failure. Samples are taken before ventilation and on the first, second, and in some cases third days after ventilation. The results show that ageing is to be considered, since the CO2/Ca ratio varies according to the age group (0.84 at 30 years and 1.35 at 60 years). Patients with respiratory failure may be distributed into two main categories: hypoxic patients without hypercapnia, and patients with predominant hypercapnia. Hypercapnic patients may be differentiated from the hypoxic ones, both before assisted ventilation and on account of the dynamic phenomena that come into play during respiratory support in this group of patients. If the equilibrium state (at least five days with rigorously steady gazometry), before assisted ventilation, remains unknown, it is not possible to distribute the patients in one of these two groups. The results' significance is discussed, as well as the possible therapeutic applications.

Bone and Bones↗
PubMedDate not supplied

[Mammography].

Mammography is the most important method for the diagnosis and the screening of breast diseases. Sensitivity and accuracy of mammography are very high in the detection of breast cancer. The use of the stereotaxic localization and fine-needle aspiration of nonpalpable breast lesions improve its effectiveness. The American Breast Cancer Detection Demonstration Project (BCDDP) has demonstrated the benefits of breast screening for women over 40 years of age. Many American medical associations and societies have adopted the guidelines based on the BCDDP results, promoting breast cancer screening for these women. However, recently released results of some randomized breast screening studies demonstrated only a 5% reduction in mortality from breast cancer in women 40-49 years of age, and a 40% reduction for women aged over 50 years. There is no explanation for this dilemma at the present time. However, screening mammography should stay available for women over 40 years of age.

Adult↗
PubMedDate not supplied

[Renocolonic fistula complicating vesicorenal reflux and xanthogranulomatous pyelonephritis in a 20-month-old child].

A case of vesico-renal reflux with xanthogranulomatous pyelonephritis complicated with a renocolic fistula in a 20 months old child is reported. Imaging in this case was crucial for the diagnosis and the work up; it included ASP, renal ultrasound, UIV retrograde cystography and CT. The treatment consisted in a right ureteronephrectomy after fistula's section.

Colonic Diseases↗
PubMedDate not supplied

[Aerodigestive papillomatosis in an infant].

A case of juvenile papillomatosis involving the supra glottic area of the larynx and the esophagus in a 10 months old infant is reported. The patient was treated by multiple Laser CO2 resections of papillomas and received autogenous vaccine. He is now 5 years; he is well and apparently free of disease for the last two years. Radiography of the larynx and esophagogram were crucial for the initial diagnosis and the followup of this child.

Esophageal Neoplasms↗
PubMedDate not supplied

[Echographic aspects of cerebral sulci in the ante- and perinatal period].

70 fetuses (10 to 37 weeks) and 30 full term infants were examined by ultrasound (U.S.). Anatomic correlations were made with frontal, axial and sagittal sections of 43 fetal and 3 neonatal brains. At 12 weeks gestational age (w.g.a.) only the inter hemispheric fissure is seen by U.S. The sylvian fissure (21 w.g.a.), the callosal sulcus (21 w.g.a.), the parieto-occipital sulcus (25 w.g.a.), the calcarine fissure (25 w.g.a.), the cingulate sulcus (26 w.g.a.) and the collateral sulcus (25-27 w.g.a.) are visualized rather late with in-utero U.S. The other sulci are more difficult to see. The peripheral location of these sulci contributes to the difficulty encountered in their visualization. The morphology of the sylvian fissure is quite characteristic on U.S. imaging and can be used to estimate the gestational age of the fetus. Compared to the embryological development there is a 2-4 weeks delay between the first infolding of the brain and the visualization of a sulcus by U.S. Abnormal sulcal patterns can be recognized based on the normal appearance for each gestational age. Sulcal anomalies are quite specific in holoprosencephaly, lissencephaly, micropolygyry, schizencephaly, agenesis of the corpus callosum. Silhouetting of the sulci may occur if the parenchymal echogenicity is sufficiently increased that the sulci no longer stand out (ischemia, tumors, encephalitis). Thickening of the sulci occurs in subdural hematomas, external hydrocephalus, meningitis and toxoplasmosis.

Brain↗