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Biomedical subjects

G Copinschi

Publications and source records attributed to G Copinschi.

115 records · Page 7Linked to original sources
PubMedDate not supplied

[Biologic rhythms. Nyctemeral variation in man].

CORTICOTROPIC AXIS: The nycthemeral pattern of cortisol is a good marker of the circadian clock. Cortisol levels fluctuate between a peak level, observed in the early hours of the morning, and a minimal level around midnight. This variability is considerably reduced or even abolished in Cushing s syndrome. THYREOTROPIC AXIS: The nycthemeral pattern of TSH secretion is dependent on both the circadian clock and sleep (which inhibits hormone secretion). The moment of the evening rise is a reliable marker of the circadian rhythmicity. SOMATOTROPIC AXIS: Growth hormone is essentially pulsatile. GH levels are often undetectable between pulses. The circadian rhythmicity plays only a minor role in the regulation of growth hormone secretion. LACTOTROPIC AXIS: Nycthemeral variations in prolactin secretion are mainly regulated by wake-sleep cycles; peak levels occur in the middle of the night. Prolactin secretion is also modulated by the circadian rhythmicity. GONADOTROPIC AXIS: Gonadotropins are secreted in pulses, following the pulses of GnRH secretion. In adult women, nycthemeral variations in LH are strongly modulated by the menstrual cycle. MELATONIN: The nychtemeral pattern of melatonin is an excellent marker of the circadian clock. Diurnal concentrations are low and vary little whereas peak levels are observed in the middle of the night. Melatonin rhythmicity is not influenced by sleep, but is dependent on exposure to light and darkness.

Adolescent↗
PubMedDate not supplied

[Biologic rhythms. Effect of aging on the desynchronization of endogenous rhythmicity and environmental conditions].

CIRCADIAN AND PULSATILE RHYTHMICITY IN THE AGING PROCESS: The aging process produces morphological and neurochemical alterations in the suprachiasmatic nuclei as well as major alterations in the quality of sleep. In addition, aging is frequently accompanied by changes in life style due to different, often less demanding, social and occupational activities, leading to an attenuation of the synchronizing effects of the light-dark and activity-rest cycles. Together, these different elements contribute to a decline in temporal organization in the elderly, a phenomenon which starts in the third decade for some variables. There is a characteristic phase shift with age: in an 80-year-old individual, the circadian cortisol peak occurs about 3 hours earlier than in a 20 year-old-individual. JET LAG AND NIGHT SHIFT WORK: The circadian rhythm and environmental conditions can become desynchronized after transmeridian flights, a phenomenon commonly called jet lag. In night shift workers, such desynchronization creates an important public health problem. The impact may be underestimated since 15 to 20% of the work force in industrialized countries work permanently or occasionally on night shifts. The resulting dissociation between environmental signals and the wake-sleep cycle leads to various health problems. No truly effective therapeutic strategy has been developed although ongoing research, particularly on the use of light and/or melatonin, provides some promising perspectives.

Circadian Rhythm↗
PubMedDate not supplied

[Pituitary modifications in a case of Schilder disease (author's transl)].

In a case of Schilder disease with a heavy atrophy of adrenal cortex the immunocytological analysis of anterior pituitary shows a generalized hypertrophy and a severe last of granulations of the beta cells which reacted very weakly to au anti-serum anti-ACTH 17-39. These modifications agree with biological titration proving an hypersecretion of ACTH and beta MSH.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

ACTH, cortisol and growth hormone 24-hour profiles in major depressive illness.

Circadian rhythms of ACTH, cortisol and growth hormone have been studied in eighteen major depressives (eight unipolar and ten bipolar) as well as in eight normal controls. Both unipolar and bipolar depressed patients secreted more growth hormone than normal men. This hypersecretion occurred during waking hours rather than during sleep. An early sleep GH increase was found in all but one of the normal men, but was absent in seven of the eight unipolar depressed patients, who had instead a presleep increase. No consistent disturbance of the temporal association between sleep onset and GH secretion was found in bipolar depressed patients. Both unipolar and bipolar depressed patients had higher 24 h mean cortisol levels than normal men, but no significant difference was found for 24 h ACTH levels. An early timing of the nadir of ACTH-cortisol secretion which was observed in our depressed patients also suggest that disorders of circadian time keeping may characterize major endogenous depression.

Adrenal Cortex↗
PubMedDate not supplied

[Functional results of transsphenoidal selective adenomectomy in acromegaly (40 cases)].

Forty acromegalic patients were investigated before, during and after transsphenoidal selective adenomectomy. Pre- and post-operative studies were based on HGH basal levels, OGTT, TRH and LRH stimulation tests, while HGH plasma variations were measured during operation. Selective adenomectomy normalized HGH levels in 70% of all cases (89.5% in grades I-II and 52.4% in grades III-IV); moreover in these cases, OGTT documented normal control of GH secretion. Per-operative GH levels evolution proved to be of pronostic value. Stimulation tests demonstrated normal regulation of other pituitary functions.

Acromegaly↗