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Biomedical subjects

J Durand

Publications and source records attributed to J Durand.

At least 145 records · Page 8Linked to original sources
PubMed1979

Basal level of human platelet prostaglandins: PGE1 is more elevated than PGE2.

Radioimmunoassays of platelet prostaglandins E1 and F1 alpha in platelet rich plasma or platelet suspension, demonstrate that both PGE1 and PGF1 alpha are present at higher concentrations than prostaglandins E2 and F2 alpha. Gas chromatography--mass spectrometry determinations of prostaglandins E1 and E2 in resting washed platelets confirm this difference. Lastly, there is a greater incorporation of [1--14C] acetate into prostaglandins E1 and F1 alpha compared to that into prostaglandins E2 and F2 alpha.

Blood Platelets↗
PubMed1978

[The affected medullary segment in paraplegics. Relation to sexual function in men (author's transl)].

The authors made a detailed clinical analysis of 119 stabilized total paraplegics in order to define, as precisely as possible, the limits of the medullary segment which, for each patient, had lost all its functional value. The relationships between the affected segments and the sexual capabilities of these patients show that the segment must: --exclude the sacral spinal cord if reflex erections are to occur; --underly Th. IX at least, or better still Th. XI, for psychogenic turgescence to appear; the efferent pathways seem therefore, to emerge from the cord quite close to the level which receives testicular afferent pathways; --underly or overly Th. XII, L I, and L II for at least the greater part, for emission of sperm to occur; a true abrupt ejaculation probably requires the complementary integrity of the sacral spinal cord.

Adult↗
PubMed1977

Uptake of noradrenaline in high altitude native's heart.

Uptake of 3H-noradrenaline by the heart was studied with sections of isolated atria obtained from high or lowlanders. In native highlanders, affinity for 3H-noradrenaline by human atria is more significant than in lowlanders. Furthermore, the Michaelis Menten constant is lower in high altitude native's heart.

Adaptation, Physiological↗
PubMed1977

[Late syringomyelic syndromes in paraplegics].

The authors have reviewed 35 cases in the literature and reported on 12 cases seen personally of late onset syringomyelia in paraplegics. Initial pain was found to be present in only slightly more than half the cases and an insidious onset particularly with sensory disturbance led sometimes to delayed recognition. In the fully developed case, it can closely simulate idiopathic syringomyelia with arthropathy but impairment of touch and proprioception sometimes occurs in addition. Neurosurgical treatment to the fluid-filled cavity, does not seem to modify obviously the spontaneous evolution of the condition. In 5 cases, the paraplegia was not of traumatic origin. Possible mechanisms are discussed.

Adolescent↗
PubMed1976

New method for the preparation of highly stable polysiloxane-coated glass open-tubular capillary columns and application to the analysis of hormonal steroids.

A new approach to the preparation of methylsiloxane-coated glass open-tubular capillary columns is described. A siloxane polymeric mixture is first prepared by hydrolysis of dimethyldichlorosilane. The polymer is then coated on to the previously etched glass wall by a base-catalyzed reaction to yield a non-polar system of high stability and showing satisfactory chromatographic properties. This type of column has been used for the high-resolution separations of complex hormonal steroid mixtures. The flexibility of this method should permit the preparation of capillary systems with a wide range of polarity.

Adult↗
PubMed1976

High altitude influence on the level and turn-over time of cardiac norepinephrine in rats.

In rats exposed to an altitude of 2,900 meters the level of endogenous cardiac norepinephrine decreases after the 5th day of exposure. The turner-over time of the amine proceeds in 3 steps which are probably related to periods of stress and adaptation: initial increase, important decrease from the 5th day and return to a normal value from the 12th day.

Adaptation, Physiological↗
PubMed1976

Glass capillary columns applied to prostaglandins measurement: a useful tool for gas-chromatography mass spectrometry analysis.

The difficulties to analyse prostaglandins (PG) by gas-liquid chromatography are mainly due to the lack of sensitivity of the gas-chromatograph itself (higher than 200 ng) and to the poor resolution of the packed columns. Therefore the use of glass capillary columns which has been applied with success for other biological compounds was tempting. We describe a comparison of the preparation of the columns and their use for PG analysis of standards and of human semen. A complete resolution of PG-1 from PG-2 series was achieved. The sensitivity was multiplied 100 fold with a flame ionisation detector when compared to packed columns and was equal to the one obtained with electron capture detectors without the inconveniences of this technique. The successful coupling of glass capillary columns to a mass spectrometer leads to promising results and allows profile studies of primary PG and their metabolites as seen with human semen.

Chromatography, Gas↗
PubMed1975

[Vascular responses to tilting in paraplegic subject compared to normal (author's transl)].

1 Vascular tone is higher in paraplegics than in normals, both in capacitance and resistance vessels. This is possibly correlated with the increase in circulating catecholamines which has recently been reported. 2 Tilting at 30 degrees from horizontal induces a hydrostatic increase in transmural pressure in the affected vascular bed. This pressure change causes: an initial decrease in resistance, followed by a progressive increase which can be explained by the Bayliss reflex. The time sequence and amplitude of the responses are comparable for normal and paraplegic subjects; an increase in vascular tone of the capacitance vessels (increase in venous pressure, decrease in local blood volume). This response was constantly observed in paraplegic subjects and was absent or weak in normal subjects. 3 In conclusion, reflex changes in vascular tone due to upright posture persist after traumatic section of the spinal chord. Orthostatic hypotension and blood pooling in the lower limbs in paraplegic subjects is probably due primarly to a deficit of the pumping action of the leg muscles.

Adult↗
PubMed1975

[Muscular blood flow in human highlanders and in lowlanders living at altitude (3 800 m) (author's transl)].

Muscular blood flow (MBF) was measured in the tibialis anteiror muscle by the 133Xe washout technique. Measurements were made in lowlanders at sea level, in native highlanders at 3 800 m and in lowlanders who had been living at this altitude for less than 6 months. At rest and during exercise, MBF is smaller in highlanders and in the high altitude visitors than in lowlanders. If, instead of total blood flow, the red cell flow is calculated (by multiplying MBF by the haematocrit) these differences are no longer significant at rest and are minimized during exercice. These results are consistent with reduction of cardiac output and blood supply to other regions in subjects who are acclimatized to altitude.

Adult↗
PubMed1975

[10 cases of giant lumbo-sacral neurinoma].

Among giant tumours of the cauda equina, apart from ependymomas, neurinomas merit a special place. Depending on their site, they give rise to severe lumbar pain or root pain, with, almost constantly, aggravation during the night. X ray suggests the diagnosis when one finds displacement of the bone without inflammation, a regular bony defect, well-limited and asymmetric, and when the tumour is frequently prolonges in several directions across the bony orifices, sometimes giving a very large paravertebral mass which requires a double approach during surgery. The prognosis of isolated neurinomas is excellent, with disappearance of the pain immediately after operation, regression of the neurological signs or, at any rate, stabilisation when the latter are important. As far as the problem of spinal stability is concerned, this has been solved by sufficient spontaneous bony reconstruction.

Adolescent↗