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Biomedical subjects

A Laporte

Publications and source records attributed to A Laporte.

36 records · Page 2Linked to original sources
PubMed1979

A spin label study of myelin fluidity with normal and pathological peripheral nerves.

The myelin fluidity in peripheral nerves from normal subjects and patients with neuropathy has been studied. Nerve biopsies were made in subjects without neuropathy and in patients with Guillain-Barré, alcoholic or diabetic polyneuropathies and heredodegenerative diseases. The fluidity was studied using a stearic acid spin label with a nitroxide radical at C12 (12-doxylstearic acid) which was introduced by exchange between spin label-charged BSA and nerve myelin. Spectra was obtained with a VARIAN E 109 ESR spectrometer, at temperatures from 5 to 45 degrees C. The ultrastructure of biopsied nerves was also studied. The electron spin resonance (ESR) spectra were all typical of a partially immobilized nitroxide with a distance between outer hyperfine lines (2T//) of about 50 G, at room temperature. The curve 2T// against temperature shows two critical temperatures: 10 and 30 degrees C for all nerves. No correlation could be established between ultrastructure and fluidity of nerves. However, the myelin of nerves from diabetic patients showed a significant increase in viscosity. This physicochemical modification may represent an initial alteration of the myelin sheath, and demands further investigation. No modification of the myelin fluidity was observed in any of the other nerves studied.

Adolescent↗
PubMed1979

Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3--4 days.

Seven healthy adult men, five shift-workers and two non-shift-workers (from 21 to 36 years; mean = 26.4) volunteered to record what and when they ate, both at work and at home, every day, during eight consecutive weeks (Oct. - Dec. 1974). 1) All the subjects maintained the timing of main-meal (lunch and supper) during all shifts. 2) The major intake of protein and lipid was concentrated on the two main meals during all shifts. 3) Only the pattern of carbohydrate intake was modified by the shift-work: e.g. night-shift is associated with nibbling behaviour. 4) However, shift-work and in particular the occurence of nibbling behaviour did not result in change either in the mean 24 h caloric intake, or in the percentage of protein calories. 5) The comparison between the constancy of the timing of major meals and the shift of the timing of circadian rhythm acrophases of the 5 shift-workers leads to conclude that meal timing had a poor synchronizing effect, if any.

Adult↗
PubMed1978

Comparative results of 99mTc-pertechnetate scintigraphy and computerized tomography after contrast injection in cerebral pathology.

Fifty-six patients presenting acute cerebral ischemia were investigated by means of 160 CT and 90 RN scans. CT was positive before contrast injection in 90% of cases. A total of 120 CTs were done before and after contrast injection. Only 31% of the ischemic areas were enhanced. Out of 90 RN scans, 50 showed localized uptake. The peak of scintigraphic detection was found on the 15th day of evolution, while enhancement at CT was more frequent between the 15th and 21st days. For the hematomas (13 cases) detection by RN scan depends on the size of the lesion. Among the 47 patients presenting cerebral tumor, the RN uptake depends above all on the intensity of the BBB lesion. RN uptake and CT enhancement both show the same blood-brain barrier disturbance.

Brain↗
PubMed1978

Is the rhythm amplitude related to the ability to phase-shift circadian rhythms of shift-workers?

The magnitude of the circadian acrophase adjustment deltaphi to a phase shift of socio-ecologic synchronizers (as in shift-work) varies from subject to subject. According to J. Aschoff, the ability to adjust rapidly to a phase-shift could be associated with having a small amplitude for certain circadian rhythms. To test this hypothesis, the correlation coefficient (r) between the mean circadian rhythm amplitude A and the acrophase shift deltaphi (measured after the first night-shift) were calculated from estimates of chronobiological time series analyses (Halberg's single cosinor method). Data were obtained from two groups of selected shift-workers (20 and 5 subjects, respectively). A negative correlation between A and deltaphi (the smaller the amplitude, the greater the delpaphi) was observed in the circadian rhythms of the following variables: oral temperature (r = .63;P less than .01), peak expiratory flow (r = . 53: P less than . 01), and urinary 17-OHCS (r = . 60; P less than . 01), but not for other variables such as : grip strength, urinary K+ and Na+. The small amplitude of certain circadian rhythms could be considered as an index of an individual's ability to phase-shift easily. However, chronobiological characteristics, other than the small circadian rhythm ampliture, remain to be identified, for both a better detection of one's ability to do shift-work and a better knowledge for practical applications.

17-Hydroxycorticosteroids↗
PubMed1976

[Evolutive aspects of cerebral vascular complications. Tomodensitometric study].

Seventy patients with clinical evidence of cerebral vascular accidents were studied by tomodensitometry. Forty-eight had clinical signs of acute ischaemia and, by means of 64 investigations, it was possible to follow the development of focal softening. Diagnostic difficulties encountered in the course of the first fortnight of development are described. Twenty-two patients exhibited clinical symptoms of meningeal or cerebro-meningeal haemorrhage. Eighteen haematomas were diagnosed and their development studied in 34 investigations.

Cerebral Hemorrhage↗
PubMedDate not supplied

Sexual behavior and smoking: risk factor for urethritis in men.

Two hundred men who had symptoms of urethritis and 207 controls were interviewed. Because 60% of the men were of foreign nationality, the analysis of risk factors for urethritis was undertaken separately for the French and foreign subpopulations. The risk factors for urethritis were different for the French and foreign men. For the French men who had smoked, the risk of infection was 2.9 times greater than that for men who had never smoked (95% confidence interval, 1.2-7.6), after taking type of sexual behavior into account. There is a significant increase in the risk of urethritis when the amount of tobacco consumed daily increases (P less than 0.02). This finding suggests that smoking is an independent risk factor.

Chlamydia trachomatis↗
PubMedDate not supplied

[Role of folic-acid deficiency in deficiency diseases of the nervous system. Apropos of 12 cases including an anatomo-clinical case].

The authors report 12 cases of neurological syndromes due to folic acid deficiency, due in 8 cases to chronic alcoholism. In 5 cases there was polyneuritis, 3 cases had cerebellar atrophy, whilst 4 patients had subacute combined degeneration of the cord. Folic acid deficiency occurred alone in five cases out of twelve, as in 3 cases vitamin B1 deficiency was associated, and in four cases there was malabsorption of vitamin B12. A neuropathological study of these cases showed: 1) moderate involvement of the mamillary tubercles as observed in deficiency encephalopathies. 2) severe peripheral nerve involvement especially of axonal type. 3) involvement of the anterior horns of the spinal cord with appearances of central chromatolysis and a few atrophic neurones.

Adult↗
PubMedDate not supplied

[Comparative results of 99mTc scintigraphy and computerized tomography after contrast injection in cerebral pathology (author's transl)].

140 patients have been investigated by means of computerized tomography (CT) after contrast injection and radionuclide scan (RN scan). For patients with stroke (56 cases), RN uptake was more frequent (80%) at the 15th day of evolution, enhancement of hypodense images at CT reaches 100% at the 21st day. For the others pathologies (hematoma, tumors), the main difference between both examinations, was the volume of the lesions detected. RN uptake and CT enhancement both show the same blood brain barrier disturbance.

Brain Diseases↗