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Biomedical subjects

J Durand

Publications and source records attributed to J Durand.

At least 109 records · Page 6Linked to original sources
PubMed1986

Oxygen consumption and active sodium and chloride transport in bovine tracheal epithelium.

The O2 consumption (Jr) and the short-circuit current (Ji) were measured simultaneously in bovine tracheal epithelium in vitro. In this tissue, Ji is the sum of two active transport processes, Cl- secretion and Na+ absorption. Jr was determined from the decrease of PO2 in the incubation solution, at 37 +/- 0.05 degrees C and at a PO2 around 600 torr. Microbial contamination and leaks of dissolved O2 from the solution never exceeded 4% of the rate of PO2 decrease due to the O2 consumption of the tissue. Ji and Jr were stable over 5 h of incubation under standard conditions. Ji was 106 +/- 4 nequiv min-1 cm-2 and Jr was 39.8 +/- 1.1 nmol O2 min-1 cm-2 (mean +/- S.E., n = 46). Ji was varied with several agents known to affect ion transport across the tracheal epithelium. Na+ absorption was inhibited partly with amiloride or completely following Na+ substitution with choline. Cl- secretion was selectively suppressed by furosemide. Ji was also reduced to a very low level, using ouabain or K+ suppression to inhibit the Na+-K+-ATPase. All these manoeuvres resulted in significant reductions of both Ji and Jr. Basal Jr was not affected when Ji was modified. A plot of the relative change in suprabasal Jr versus the relative change of Ji gave a straight line (r = 0.98, n = 60). A plot using absolute values yielded a stoichiometric ratio of 13.9 ions per O2 molecule, for Na+ as well as for Cl-. The stoichiometric ratio was also calculated for each experiment. Its mean value was 14.9 ions per O2 molecule. The population of the ratios was widely dispersed, but this was explained as a predictable statistical phenomenon.

Amiloride↗
PubMed1986

Time course of muscular blood metabolites during forearm rhythmic exercise in hypoxia.

O2 concentration, PO2, PCO2, pH, osmolarity, lactate (LA), and hemoglobin (Hb) concentrations in deep forearm venous blood were repeatedly measured during submaximal exercise of forearm muscles. Concentrations of arterial blood gases were determined at rest and during exercise. Experiments were conducted under normoxia and hypobaric hypoxia (PB = 465 Torr). In arterial blood, data obtained during exercise were the same as those obtained during rest under either normoxia or hypoxia. In venous muscular blood, PO2 and O2 concentration were lower at rest and during exercise in hypoxia. The muscular arteriovenous O2 difference during exercise in hypoxia was increased by no more than 10% compared with normoxia, which implied that muscular blood flow during exercise also increased by the same percentage, if we assume that exercise O2 consumption was not affected by hypoxia. Despite increased [LA], the magnitude of changes in PCO2 and pH in hypoxia were smaller than in normoxia during exercise and recovery; this finding is probably due to the increased blood buffer value induced by the greater amount of reduced Hb in hypoxia. Hence all the changes occurring in hypoxia showed that local metabolism was less affected than we expected from the decrease in arterial PO2. The rise in [Hb] that occurred during exercise was lower in hypoxia. Possible underlying mechanisms of the [Hb] rise during exercise are discussed.

Adult↗
PubMed1986

[Migratory circuits in western Mexico].

The author examines patterns of internal and international migration in western Mexico. "Drawing on data from different sources and statistics, the essay demonstrates the importance of both types of migration, the changes in endogenous and exogenous factors which have affected the life and the migratory patterns of the population of this region. The migratory circuit being a flow not only of persons, but of goods and capital as well, the cities, specifically that of Guadalajara, have a strategic importance. They fulfill various functions and have become the backbone of the migratory process: they serve as centers for attracting and 'hosting' internal migrants as well as places of origin for other migrants; jumping-off points for international migrants; and the milieu in which many returning migrants of rural origin settle." (SUMMARY IN ENG AND FRE)

Americas↗
PubMed1986

Effects of harmaline on ion transport and oxygen consumption by the bovine tracheal epithelium.

The alkaloid harmaline is known to affect various membrane transport systems. This study examines the action of the drug on the short-circuit current (I0) and on the oxidative metabolism (Jr) in the tracheal epithelium of the cow. In this tissue I0 corresponds to the sum of two active transports: Na+ is absorbed and Cl- is secreted by a process based on the activity of the Na+ pump. A well defined relationship has been previously demonstrated between these active transports and the rate of O2 consumption (Schoenenweid et al., 1984 b). Low concentrations of harmaline (10(-6) to 5.10(-6) M) induced a small stimulation of I0. In contrast, larger concentrations (between 5.10(-5) and 10(-3) M) yielded a dose-related inhibition of I0, with an apparent concentration yielding 50% of maximal effect of 7.1.10(-4) M and maximal effect approaching 100%. The action was fully reversible after removal of the drug. The measurements of the fluxes of 22Na and 36Cl revealed that harmaline at a concentration of 8.10(-4) M, which decreased the I0 by 74 +/- 1% (n = 23), diminished both Na+ and Cl- transports, by 81 and 52%, respectively. The time course of I0 decay following the administration of harmaline was made of three components, with half-times of 0.34, 2.2 and 15.2 min. The time course was not appreciably modified when Cl- secretion was abolished with furosemide. Although harmaline, 10(-3)M, inhibited markedly I0, it did not modify Jr significantly. In contrast, when K+ in the incubation solution was omitted, both Ji and Jr were lowered.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMed1986

Effects of chloropyramine, dimethindene and diphenhydramine on transepithelial ion transport: studies in bovine tracheal epithelium and frog skin.

The effects on transepithelial ion transports of chloropyramine, dimetindene and diphenhydramine, which are three antagonists of H1-receptors of histamine, were examined in bovine tracheal epithelium and in frog skin. The short-circuit current I0 across bovine tracheal epithelium is the sum of active secretion of Cl- and absorption of Na+. In this tissue, all three drugs induced a reversible, dose-related inhibition of I0, up to 100%. The concentrations giving 50% of maximal effect were 1.4 X 10(-4) M for chloropyramine, 2.0 X 10(-4) M for dimetindene and 2.5 X 10(-4) M for diphenhydramine. The effect was unrelated to the agonist binding site of H1-receptors of histamine, since it was not altered in the presence of 10(-3) M histamine. Experiments in which Na+ transport was selectively reduced by 5 X 10(-5) M amiloride, or in which Cl- transport was selectively abolished by 10(-3) M furosemide, 10(-4) M bumetanide or Cl- removal, indicated that Na+ and Cl- transports were equally affected by the drugs. The action of chloropyramine was composed of an early inhibition of Na+ and Cl- movements, followed by a slow recovery of Cl- secretion. In frog skin, each one of the three H1-antagonists modified the I0, following two main patterns of response, a stimulation at the lower concentrations tested, or an inhibition at higher concentrations. Dose-response relationships were obscured by a large variability in response of individual skins. These observations in bovine tracheal epithelium and frog skin suggest that H1-antagonists might alter the functioning of other epithelia as well.

Animals↗
PubMed1984

Changes in rectal and mean skin temperature in response to suggested heat during hypnosis in man.

Rectal temperature, mean skin temperature and heart rate were recorded in 7 subjects during hypnosis, induced either alone or while sensations of heat were suggested. During hypnosis alone, a fall in the heart rate of about 10 beat X min-1 was the only autonomic response observed; body temperatures were unaltered. In contrast, during hypnosis with suggestion of heat, the following changes occurred: (1) Mean rectal temperature decreased 0.20 degrees C (p less than 0.05) within 50 min. Its mean time course differed significantly from that for hypnosis alone (p less than 0.001). (2) Comparison of individual rectal temperature time sequences showed that in fact this temperature only declined in 4 subjects out of 7, and tended to form a plateau located 0.35 degrees C below the value of the preceding waking state. Despite reinforcement of heat suggestion, the plateau continued until the end of the hypnotic trance. (3) Mean skin temperature tended to rise. (4) When hypnosis with suggestion ceased, both rectal and skin temperatures very slowly returned to their levels during the preceding waking state.

Adult↗
PubMed1984

High efficiency capillary column-gas chromatography mass spectrometry: analysis of the lipoxygenase pathway in eukaryot cells.

Lipoxygenases are ubiquitous enzymes able to oxygenate polyunsaturated fatty acids. This metabolic pathway leads to hydroperoxides, hydroxyepoxyene compounds and leukotrienes. Using high performance gas chromatography prior to mass spectrometry, we studied the activity of the lipoxygenases from mouse peritoneal macrophages. Further studies on mechanism of biosynthesis of hydroxyepoxyene compounds were successfully carried out using 18O2 labelled precursors.

Animals↗
PubMed1984

Current-induced volume flow across bovine tracheal epithelium: evidence for sodium-water coupling.

The passage of a constant current from lumen to serosa (Il-s), in the range 0.5-2.0 mA, across ouabain-treated bovine tracheal epithelium, induced a stable volume flow (Jv) toward the serosa, proportional to the current. No consistent Jv occurred when current was applied from serosa to lumen. When the standard K+ (6 mM) in the bathing solution was omitted or replaced by choline, Jv was in the same direction as, and proportional to, the current, both with Is-l and with Il-s. The electro-osmotic permeability beta was in the range of 10-15 microl h-1 cm-2 mA-1, i.e. 3-4 X 10(-6) cm s-1 mA-1. The fluxes of Na+, Cl- and mannitol were measured in current-clamp (1 mA, passed from serosa to lumen or lumen to serosa) or voltage-clamp (-20, 0 and +20 mV) conditions, with and without K+. Net transepithelial Na+ fluxes toward the cathode were either smaller than (with Is-l) or equal to (with Il-s) the net fluxes of Cl- toward the anode. The total transepithelial conductance (Gt) increased with the applied electrical gradient, both with Is-l and with Il-s, the change in Gt being larger with Il-s than with Is-l. This increase of Gt was less pronounced when K+ was omitted. The analyses of partial ionic conductances (GNa and GCl) and of the flux ratios indicate the existence of non-conductive diffusion for Cl- and also for Na+. The direction of the electrical gradient influenced the permeability ratio PNa/PCl. With Is-l, PNa/PCl was consistently lower than 0.7, i.e. the mobility ratio of Na+ and Cl- in solution. With Il-s, PNa/PCl was closer to 0.7. The highest Cl- selectivity of the epithelium was observed with Is-l in the presence of K+, i.e. under conditions which failed to induce any conspicuous Jv. The passage of current at 1 mA induced a net flux of mannitol toward the cathode, i.e. in the same direction as Na+ net flux and Jv. However, this mannitol flux was significant only in the absence of K+. These results indicate that Jv was predominantly coupled to the migration of Na+ along the electrical gradient, through a paracellular pathway.

Animals↗
PubMed1983

Hydroperoxyeicosatetraenoic acids. Potent inhibitors of lymphocyte responses.

Arachidonic acid can be transformed into a series of HPETEs by the lipoxygenase enzyme activity of mouse peritoneal macrophages. These resulting HPETEs inhibit some mouse lymphocyte responses. When mice are injected with 15-L-HPETE, their splenocytes show a decreased [3H]thymidine uptake after lectin stimulation.

Animals↗
PubMed1983

Morphological and electrophysiological properties of trigeminal neurones projecting to the accessory abducens nucleus of the cat.

Horseradish peroxidase was injected into the somata or axons of neurones located in the nucleus oralis of the spinal trigeminal complex and projecting to the accessory abducens nucleus. A group of 43 axons with electrophysiologically identified responses to the stimulation of three different areas of the face were studied. The latencies of their orthodromic responses following trigeminal stimulation and their pattern of discharges were compared to those of secondary trigeminal neurones and retractor bulbi motoneurones. Labelled trigeminal axons were found to generate collaterals for the accessory abducens nucleus. Terminal ramifications are present in the rostro-caudal part of the motor nucleus where the dendritic arborization of the motoneurones has been described. Connections to facial and trigeminal motor nuclei were also present, suggesting that secondary trigeminal axons distributed the information to the three motor targets at the brain stem level. It is suggested that the trigemino-retractor bulbi reflex is part of facial reflexes involved in orienting reactions, and protective responses resulting in coordinated movements of the facial musculature.

Abducens Nerve↗
PubMed1983

Ultrastructural and electrophysiological properties of accessory abducens nucleus motoneurones: an intracellular horseradish peroxidase study in the cat.

The physiological and morphological (light and electron microscopy) properties of six retractor bulbi motoneurones were analysed using the technique of intracellular recording and intracellular labelling with horseradish peroxidase. The retractor bulbi motoneurones were identified by antidromic invasion and orthodromic responses following stimulation of trigeminal afferents were studied. Two of these motoneurones were examined ultrastructurally. Terminal boutons forming synapses with labelled soma, labelled proximal and distal dendrites were characterized. Serial sections allowed the axon hillock to be analyzed and the initial segment of a presumed motoneurone to be observed in the section where the injected motoneurone was described. The ultrastructure of unidentified elements observed in the accessory abducens nucleus is stressed.

Abducens Nerve↗
PubMed1983

Intersubject viability in growth hormone time course during different types of work.

This study addresses the question of variability of immunoreactive human growth hormone (IRHGH) response to the following types of muscular exercise. 1) One hour of submaximal exercise with restarting for 30 min after 20 min of recovery. Three types of responses were observed: a rise of [IRHGH] occurred in response to muscular activity; [IRHGH] was maintained at rest level during the first bout and then rose in the second bout; or [IRHGH] rose during the first bout and was no longer modified by the restarting. 2) Thirty minutes of heavy exercise. In some subjects [IRHGH] change was almost linear with time, reaching very high values and dropping as soon as exercise had stopped, whereas in others peak values were similar to those of submaximal exercise but, in contrast, plateaued during recovery. 3) One hour of exercise performed either continuously or with alternate sequences of 30-s exercise and 30-s pause. In intermittent exercise, some subjects displayed a similar time course of [IRHGH] as in continuous exercise and others displayed markedly high values. 4) One hour of submaximal exercise at three different intensities carried out at ambient temperatures of 24 and 33 degrees C. At 33 degrees C, in some subjects, [IRHGH] time course at the three intensities was unchanged at 33 degrees C compared with that at 24 degrees C, whereas the maximal value increased in another subject up to 150 ng X ml-1. A significant intrasubject consistency to a given type of exercise was evident over several months. The study emphasizes that caution should be used in drawing definite conclusions from averaged results with high variability.

Adult↗
PubMed1982

A randomized trial of adjuvant chemotherapy and immunotherapy in cutaneous melanoma.

In a randomized trial of adjuvant chemotherapy, immunotherapy, or immunochemotherapy, 761 evaluable patients with pathological Stage II cutaneous melanoma anywhere on the body or with pathological Stage I melanoma of the trunk (Clark's level 3 to 5) were studied by the World Health Organization International Melanoma Group. Wide local excision and excisional regional lymphadenectomy alone were performed in 185 patients and the results were compared with those of surgery plus chemotherapy with dacarbazine (in 192 patients), surgery plus immunotherapy with bacille Calmette-Guérin vaccine (in 203), and surgery plus chemotherapy combined with immunotherapy (in 181). The rates of disease-free survival and overall survival at 36 months were 30.4 +/- 8.3 per cent (mean +/- S.E.) and 41.6 +/- 10.0 per cent, respectively, after surgical treatment alone; 37.2 +/- 7.9 per cent and 46.5 +/- 8.3 per cent after surgery plus chemotherapy; 34.8 +/- 7.9 per cent and 48.7 +/- 8.7 per cent after surgery plus immunotherapy; and 33.6 +/- 7.9 per cent and 50.0 +/- 8.8 per cent after surgery plus a combination of chemotherapy and immunotherapy. None of the differences between groups was significant, and thus no effect of adjuvant therapy could be demonstrated in this study.

BCG Vaccine↗
PubMed1982

[Ejaculation problems in traumatic paraplegia ].

Basing themselves on 149 cases, the authors describe the spinal neurophysiology of ejaculation in spinal man, and put forward certain hypotheses. They suggest that the reflex of seminal emission is a lumbar reflex, which may be dependent on conductive factor originating in the upper neurological structures, and that the orthosympathetic system, which leaves the spinal cord through the thoracolumbar junction, could provide a highway for the psychological nerve impulses inducing seminal emission.

Adolescent↗
PubMed1982

[Cranio-vertebral junction and Morquio disease. Apropos of 6 cases].

The authors study the anomalies of the cranio-vertebral junction in the Morquio disease. The first 6 cases reported, in addition to the usual vertebral anomalies, suffered from a junctionnal malformations that were operated by posterior decompression and occipito-vertebral arthrodesis. In these cases, they especially study: --the neurological repercussion in 5 cases that could only be evidenced by a very careful examination after a stress test; --the simple roentgenographic examination, in forced position, and gaseous myelography proved on one band, that the instability, which is supposed to be responsible for the neurological symptoms, is actually inconstant (2 case out of 6). But on the other hand a narrow canal was present in every cases; --the surgical procedure performed in the 6 cases consisted of a removal of the posterior arch of the Atlas, of a widening of the occipital foramen if necessary (4 cases) and of an occipito-vertebral arthrodesis. There has been no aggravation compared to the previous state. Three indisputable improvements in the cases with a pyramidal syndrome. The authors compared their cases to those published in the literature and on which most of the time only a simple stabilisation was performed. For the authors this stabilisation can only be considered as a complementary procedure to the decompression which remains the main part of the treatment. The indications are discussed: they are based on the neurological examination and the myelography.

Arthrodesis↗