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Biomedical subjects

G Manciet

Publications and source records attributed to G Manciet.

At least 37 records · Page 2Linked to original sources
PubMed1988

The electrophysiological effects of thyrotropin-releasing hormone are similar in human TSH- and prolactin-secreting pituitary cells.

We studied the electrophysiological properties of individually characterized TSH-secreting cells cultured from pituitary fragments surgically removed from three patients, two who had primary TSH-secreting adenomas and one who had chronic TSH hypersecretion (hyperplasia) secondary to primary hypothyroidism. The TSH-secreting cells were excitable and had calcium-dependent action potentials. More than 80% of the cells cultured from the two patients with TSH-secreting adenomas were spontaneously active, whereas fewer cells (20%) cultured from the hypothyroid patient were spontaneously active. TRH (50 nmol/L) induced a complex pattern of electrical changes. The initial response was transient hyperpolarization (activation of potassium conductance), followed by increased low amplitude voltage fluctuations occasionally leading to action potentials. These TRH-induced electrophysiological changes were similar to those reported in rat and human PRL-secreting adenoma cells. These results suggest that TRH may have an identical mode of action in tumoral PRL and TSH cells. In the cells from the hypothyroid patient, the initial response to TRH cells was similar, but the second phase response was greater. The findings that the cells cultured from these patients behaved differently with regard to their electrophysiological characteristics (action potentials) and responses to TRH may reflect the different clinical conditions from which they were derived.

Action Potentials↗
PubMed1988

Thallium-201 imaging in the follow-up of differentiated thyroid carcinoma.

Since thallium-201 imaging has been reported as a potential means of follow-up of patients with differentiated thyroid carcinoma (DTC) during ongoing thyroid suppression therapy, the authors evaluated the diagnostic sensitivity of this procedure in 31 patients known to have metastases or local recurrence. Among 51 tumor sites 201TI imaging had a detection rate of 45% whereas 84% was noted for imaging with 131I administered in therapeutic doses. Thus, even though the effectiveness of the two radionuclides is not strictly comparable due to the difference in the administered doses, Thallium imaging cannot be recommended as the only modality for the follow-up of patients with DTC. Six of the eight tumor sites negative with 131I were positive with 201TI (especially metastatic cervico-mediastinal lymph nodes). So 201TI imaging may particularly be helpful in localizing metastases or recurrences in patients with a negative 131I scan and abnormal levels of serum thyroglobulin.

Bone Neoplasms↗
PubMed1987

Hemorheological changes in elderly subjects--effect of pentosan polysulfate and possible role of leucocyte arachidonic acid metabolism.

The effects of pentosan polysulfate (PPS) on various hemorheological parameters were studied in a group of very elderly subjects in good general health. Alterations in blood viscosity and filterability were detected in these patients, without any concomitant changes in factors which are known to affect these parameters: notably hematocrit, fibrinogen and plasma lipid levels. The hemorheological abnormalities were considerably improved by twice daily treatment with 50 mg of PPS (i.m.). Apart from its anticoagulant activity, PPS has been shown to have an anti-inflammatory action. We were interested to investigate its effects on metabolism of exogenous arachidonic acid (AA) by both platelets and leucocytes. It is becoming increasingly recognized that metabolites of AA via the 5 LO pathway appear to play a role in inflammatory processes. In this study, PPS was found to inhibit leucocyte 5 LO activity. Reduction in the levels of these metabolites may therefore have an effect on whole blood rheology.

Adult↗
PubMed1986

[Malaise and loss of consciousness in the elderly patient: prospective evaluation of methods of investigation].

60 consecutive patients (mean age: 80,7 yrs; s.d.: 6,1 yrs; range 70-94 yrs) referred to a geriatric medicine department with syncope or dizziness were proposectively compared with 40 age and sex matched controls. A battery of non-invasive investigations including tilt-test, glycemia, 12 lead ecg., eeg, 24 hour ambulatory ecg recording,. M--mode echocardiogram and cervical Doppler velocimetry was applied blindly to patients and controls. The proportion of abnormalities was similar in both groups having sick sinus syndrom or complete atrio-ventricular block versus no control (p less than 0.05). By contrast history-case was of great predictive value: 6 of 13 patients reporting abrupt syncope had a 24 ecg recording showing sick sinus syndrom or complete atrio ventricular block, versus 2 of 47 other patients (p less than 0,01); 11 of 14 patients reporting orhostatic dizziness or syncope had a tilt-test consistent with orthostactic hypotension versus 6 of 46 other patients (p less than 0,01).

Accidents↗
PubMed1985

[Peripheral sensitivity to insulin in aged subjects].

Insulin sensitivity has been studied in ten young patients (22 years old means) and in eleven elderly patients (72 years old means). They were free of family diabetes history, glucose intolerance, hypertriglyceridemia, hepatic or renal failure or factor of insulin resistance such as infectious diseases. A two hours hyperinsulinic euglycemic clamp was done with an artificial pancreas (Biostator GCIIS Miles). The ten young patients and the eleven old patients had a stable hyperinsulinic level (93.3 +/- 5 uu/ml and 90 +/- 8 uu/ml) they respectively required 8.08 +/- 0.73 and 5.5 +/- 2.5 mg/kg/min of glucose. Metabolic clearance of insulin does not seem altered with aging. For a same hyperinsulinic level the glucose requirement is less in old patients. So there is an apparent insulin resistance in aging.

Adult↗
PubMed1985

Postprandial thermogenesis and hormonal release in lean and obese subjects.

One group of 10 obese people (1.72 times normal weight) was compared to a control group of 9 normal-weight subjects. Oxygen consumption (VO2), immuno reactive growth hormone (IRGH), and rectal temperature (Tre) were measured every 15 min on an average, during the 5 h following a protein meal composed of 6 egg-whites and 50 g of casein totaling 1 340 kJ. The results show that postprandial thermogenesis (PPT) is the same in both groups: maximum increase in VO2 averages 15% in the obese and 16% in the control groups respectively. Energy expenditure integrated over the 5 h was 129 kJ for the obese and 114 kJ for the control subjects, i.e. 9.6% and 8.5% of the energy meal content. The rise in Tre was identical for both groups (0.4 degrees C over 3 h). For IRGH, the preprandial reference figures were much lower in the obese: 52 pmole.dm-3, as compared to 145 pmole.dm-3. In all control subjects, the protein meal resulted in a IRGH peak of, on average, 455 pmole.dm-3 about 2 h after. This was not observed in 4 of the obese subjects, while in the remaining 6, the mean peak value was 165 pmole.dm-3, occurring after 1 h. The other hormonal or chemical compound simultaneously analysed (glucagon, cortisol, PRL, T3, glucose, lactate, NEFA) do not show any significant variations but insulin blood level for which a postprandial increase was measured in both groups. It is concluded that after a protein test meal: PPT in overweight people is no different from that in people of normal weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Study of insulin metabolism in hyperthyroid patients.

Hyperthyroidism is associated with degradation of carbohydrate metabolism. The insulin metabolism in 12 hyperthyroid patients is compared with 10 control subjects. The patients were connected to an artificial beta cell (Biostator GCIIS Miles) for two hours of insulin infusion (40 mU/m2/mn) while glycemia was maintained at its basal level by a modulated glucose infusion. Blood samples were taken, every 15 minutes for insulin and C peptide dosage. In control subjects the insulin steady state level was 93.3 +/- 5 microU/ml whereas this ranged from 42 +/- 3.4 microU/ml to 68 +/- 3.9 microU/ml in hyperthyroid patients. After treatment the insulin level was not quite normal, and ranged from 52 +/- 4.8 microU/ml to 82.2 +/- 9 microU/ml. A glucose intake not corresponding to the same insulin steady state is not therefore to be interpreted. Here there is no evidence of a correlation between the percentage decrease in the insulin test level and the thyroid hormone levels. An impairment of insulin metabolism is suggested in hyperthyroid patients, which might contribute to the decrease in carbohydrate tolerance.

Adult↗