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Biomedical subjects

F Stephan

Publications and source records attributed to F Stephan.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Role of retino-hypothalamic pathways in the entrainment of drinking rhythms.

The role of retino-hypothalamic pathways in the re-entrainment of drinking rhythms after a 12 hr phase shift in the light-dark cycle was investigated by comparing the rate of re-entrainment of unilaterally blinded (UB) rats, with split optic chiasms (OCS) and controls. As reported previously, UB rats required more days to invert drinking rhythms than controls. The number of days required to re-entrain OCS rats fell between controls and UB rats but was not statistically significant from either group. Since OCS rats had the fewest retino-hypothalamic connections, the amount of retinal input to the surachiasmatic nuclei does not appear to play an important role in the rate of re-entrainment. The results are consistent with the hypothesis that the unequal distribution of retiono-hypothalamic fibers in UB rats interferes with the entrainment process. Compared to controls, both UB and OCS rats showed a small but significant post-operative reduction in the nocturnality of drinking.

Afferent Pathways↗
PubMedDate not supplied

[Variation in serum nonesterified fatty acids during glucose tolerance test in undernourished patients with anorexia nervosa and in obese patients].

Intravenous glucose tolerance tests (0,33 g glucose per kg body weight) are performed in 11 self starved women suffering from anorexia nervosa, 10 obese and 8 normal women. They have no genetic or chemical diabetes and belong to the same age group. Plasma concentrations of immuno-reactive insuline (IRI) and non esterified fatty acids (NEFA) are determined during these tests. The basal concentrations of NEFA are very high in the obese patients. In the starved women the elevation of the basal plasma NEFA concentration is less striking and statistically not significant. The plasma level of NEFA is reduced in all subjects by hyperinsulinism secondary to hyperglycemia. This drop in NEFA concentration is significantly reduced in the obese patients and markedly inhibited in the starved women. This observation points toward an increased resistance to the antilipolytic action of insulin in anorexia nervosa because, in these patients, the glucose load determines a normal increase in plasma IRI but the fall in plasma NEFA concentration is severely impaired.

Adolescent↗
PubMedDate not supplied

[Clinical and biological patterns of hyperthyroidism in elderly patients (author's transl)].

Aetiological, clinical and biological patterns of hyperthyroidism are studied in 22 consecutive patients over the age of 65 years. In this group the frequency of toxic multinodular goiter and Graves disease are grossly the same. A previous iodine administration could be a significant aetiologic factor in 8/22 patients. The clinical symptomatology is characterized by the predominance of cardiovascular disorders and by the mildness or absence of the other symptoms of thyrotoxicosis. The classical abnormalities of thyroid function tests are only found in 65% of our patients. The others have high total and free thyroxine (T4) and normal triiodothyronine (T3) plasma levels with a marked increase in reverse T3 (RT3) levels. These abnormalities result possibly from an impairment of the peripheral conversion of T4 to T3 as it is seen in fasting or in sick euthyroid patients. Most of our hyperthyroid patients had an associated disease and were undernourished. In the elderly patient the determination of plasma T4 by a radioimmunoassay and the T3 uptake test are the best screening methods for detecting an often hidden thyrotoxicosis.

Aged↗
PubMedDate not supplied

[Hyperthyroidism and subjects hyperresponding to thyrotropin. Importance of simultaneous thyrotropin and prolactin determination following administration of thyroid-releasing hormone].

Primary hypothyroidism is assessed by increased basal and TRH-induced TSH levels. Since basal and TRH induced prolactin (PRL) levels may also be modified by the thyroid status, TSH and PRL responses to TRH are simultaneously determined in patients with mild or evident primary hypothyroidism (n = 22) and in TSH hyperresponders (n = 28) with clinicobiological appearance of euthyroidism. In evident hypothyroidism (free thyroxine index FT4 I = 0,4 +/- 0,1) basal PRL are increased in 8 out of 11 patients and TRH-induced PRL responses are exaggerated in all cases like in mild hypothyroidism (FT 4 I = 1,2 +/- 0, 1) A negative correlation is found between maximal PRL levels and triiodothyronine (T3) levels (p less than 0,01). In presumed euthyroid TSH hyperresponders (FT4 I = 2,2 +/- 0,1) PRL response to TRH is exaggerated in only 7 patients and no correlation exists between maximal PRL and T3 levels. These data suggest that simultaneously exaggerated TSH and PRL responses to TRH are presumably patterns of potential hyperthyroidism for the diagnosis of which the determination of TSH alone seems to be necessary but insufficient.

Adolescent↗
PubMedDate not supplied

[Influence of nutritional factors on the enhancement of renal compensatory hypertrophy by hyperadrenocorticism in the rat (author's transl)].

In the rat compensatory hypertrophy (RCH) was enhanced by hyperadrenocorticism induced by the administration of a long acting ACTH at a dose of 18 Y/100 g body weight/d. for 7 d. after uninephrectomy (UN). In the present experiments we compared the differences delta between the weight, the content in protein, RNA and DNA of the left solitary kidney and the same determinations done on the right kidney excised at UN 7 d. earlier. The rats drank freely a isotonic solution of NaCl (G1) or KCl (G2) or glucose (G3, G4). The rats of group G1, G2 and G3 received a standard solid food; the G4 rats ate a K poor diet. About half of the animals were treated with ACTH. RCH occurred in all the rats even when they lost body weight. The pain in weight of the solitary kidney was enhanced in all the rats treated with ACTH but not in the G2 rats loaded with KCl. This renotrophic action of hyperadrenocorticism was most prominent in the K depleted G4 rats. The protein/DNA ratio, a marker of cellular hypertrophy, was increased by hyperadrenocorticism in the G1 and G2 rats drinking respectively the NaCl or the KCl solutions. This ratio did not change in the ACTH treated G3 and G4 rats drinking the glucose solution suggesting that, in this experimental condition, cellular hyperplasia and hypertrophy occurred at the same extent. These experiments suggest that, in the uninephrectomized rat, the renotrophic action of ACTH is modulated by nutritional factors. The enhancement of RCH by ACTH may be related to hyperglycemia, hyperinsulinism or altered handling of Na+ and K+ by the nephron.

Adrenocortical Hyperfunction↗
PubMedDate not supplied

[Different effects of tricyclic (clomipramine and amitriptyline) and tetracyclic (maprotiline) antidepressors on the release of thyroid stimulating hormone, prolactin and growth hormone to thyrostimulating releasing hormone in patients with psychoaffective disorders (author's transl)].

The hormonal alterations induced by tricyclic and tetracyclic antidepressors (AD) were studied in patients with psychoaffective disorders (PAD) to ascertain the role of certain biogenic amines in the regulation of thyroid stimulating hormone (TSH), prolactin (PRL) and growth hormone (GH). The responsiveness of plasma TSH, PRL and GH to synthetic thyrostimulating release hormone (TRH; 250 microgram i.v.) was determined in 57 patients distributed in 5 groups according to the treatment: 10 non treated patients, 16 tricyclic (clomipramine and amitriptyline) treated patients, 6 patients treated by clomipramine in association with lithium, 6 tetracyclic (maprotiline) treated patients and 19 patients treated by major neuroleptics. Results of untreated patients were compared to those observed in 10 age and sex matched normal subjects. Basal plasma levels of TSH were normal in all the patients. The TSH response to TRH (delta TSH) was blunted in non treated patients. delta TSH was normal in the patients treated by maprotiline or neuroleptics and increased in the group treated by tricyclic AD in association with lithium. Basal plasma levels of PRL and PRL response to TRH (delta PRL) were decreased in the women treated by tricyclic AD, but remained normal under maprotiline. They were markedly increased in the neuroleptic group. No inadequate response of GH to TRH was noted in our series of patients. The different hormonal effects induced by AD--dissociation between delta TSH and delta PRL under tricyclics and normal or increased delta TSH under maprotiline--may be logically explained by the various ways of action of these AD on the brain monoamines. delta TSH decrease and tendency to an increased delta PRL observed with clomipramine argue for a serotoninergic regulation of these two hormones, whereas the normalisation of delta TSH under maprotiline argues for a noradrenergic regulation of this hormone. Effectively, tricyclic AD inhibits mainly the serotonin recaptation and tetracyclic inhibits rather norepinephrine recaptation. The persistent delta TSH increase observed in the group treated by the association clomipramine-lithium demonstrates that the tricyclics do not interact with the hypophyso-thyroid positive feedback.

Adult↗
PubMedDate not supplied

[Thyroid function in patients with alcoholic cirrhosis (author's transl)].

Total serum thyroxine (T4), total serum triidothyronine (T3), thyrotropin (TSH) and TRH induced TSH release have been measured in 50 clinically euthyroid men with alcoolic cirrhosis and compared to 20 age matched control men in order to determine the thyroid status in cirrhosis. Free serum thyroxin (FT4), free triiodothyronine (FT3) and reverse T3 (rT3), were measured in 34 patients. In these patients, a clinical and biological index was devised to score the severity of the disease. Finally, thyroxine-binding-globulin (TBG) levels were measured in 20 patients. In cirrhotics, the mean total T4 level is normal but the mean T3 level is markedly reduced: FT4 is slightly raised and FT3 is decreased. Serum rT3 levels are often very high and correlated in T3. Basal TSH concentration were slightly significantly higher than normal; the mean magnitude of TSH responses to TRH is comparable to controls but the individual responses are very variable, insufficient or exaggerated, and non correlated with other thyroid function tests. The mean TBG level is also normal and non correlated with total free thyroid hormones. Correlation of thyroid function tests with liver function showed significant correlations between T3, FT3, rT3 or TSH and serum albumin concentration and particularly between T3, rT3 and the clinical and biological index. So the ratio rT3/T3 may be proposed as a valuable index of prognosis and severity of the disease. In conclusion, in alcoholic cirrhosis, thyroid function and regulation are characterized by normal T4 and low T3 levels related to reduced extrathyroidal T4 and T3 conversion levels - and thus maintain the euthyroid state - and by a hypothalamo-pituitary dysfunction. These alterations are related to the degree of liver dysfunction.

Humans↗