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Biomedical subjects

A Luyckx

Publications and source records attributed to A Luyckx.

At least 37 records · Page 2Linked to original sources
PubMed1981

Glucose oxidation in relation to the size of the oral glucose loading dose.

Using "naturally labeled 13C-glucose" the conversion to expired air CO2 of 100, 66 and 33 g oral glucose loads was evaluated, during 7 hr, in 6 male healthy volunteers. The total amounts of exogenous glucose converted to expired air CO2 were proportional to the loading doses and averaged, in g/7 hr, 14.6 +/- 2.1 for 33 g, 20.8 +/- 2.1 for 66 g and 31.2 +/- 1.6 for 100 g. In contrast total glucose oxidation, evaluated by indirect calorimetry, was similar in the three groups and was not correlated with the dose of glucose given. The plasma insulin response was significantly correlated with the load of glucose (r = 0.86; p less than 0.001) whereas such correlation was not observed with the blood glucose response. Comparison with data available in the literature on the influence of the size of the oral glucose load on endogenous glucose production and on splanchnic glucose output suggests that the greater oxidation of exogenous glucose seen when the oral load of glucose is increased essentially results from a greater enrichment of the systemic glucose pool with exogenous glucose.

Adult↗
PubMed1981

Glucagon immunoreactivity and antidiabetic action of somatostatin in the totally duodeno-pancreatectomized and gastrectomized human.

Ten patients who had been totally duodeno-pancreatectomized and totally (N = 1) or partially gastrectomized (N = 9) for chronic pancreatitis (N = 9) or pancreatic carcinoma (N = 1) were investigated. None had a measurable basal level of either plasma C-peptide or a C-peptide response to i.v. glucagon. Immunoreactive glucagon (IRG) was present in all patients, and the mean level (69 +/- 8 pg/ml) was not significantly different from the mean observed in normal subjects (81 +/- 16 pg/ml). Plasma IRG was unequivocally stimulated by arginine in 2 of the 10 subjects. The effect of somatostatin on plasma glucose and IRG during an oral glucose tolerance test was studied in 5 of the 10 patients. The effects of somatostatin on spontaneous hyperglycemia, plasma growth hormone, and IRG after withdrawal of insulin treatment was studied in 4 patients. Somatostatin blunted both the hyperglycemic and paradoxical IRG responses to the glucose challenge, and reduced the spontaneous rise of blood glucose that occurred after insulin withdrawal. This latter effect was not related to clear-cut changes in plasma growth hormone or in IRG. These data confirm the existence of circulating IRG in pancreatectomized patients and demonstrate the presence of circulating IRG in a completely gastrectomized and pancreatectomized patient. The somatostatin-induced improvement in glucose tolerance in the oral glucose tolerance test seems to be related to a reduction of the paradoxical IRG response. In contrast, the inhibition by somatostatin of the rise in blood glucose which occurs after insulin withdrawal does not seem to be mediated through IRG or growth hormone.

Adult↗
PubMed1981

[Decreased secretion of epinephrine during protein-supplemented fasting in obese subjects (author's transl)].

The protein-supplemented fasting induces a progressive but moderate decrease in blood glucose (-26%) and a marked rise in plasma free fatty acids levels (+ 43%). Nevertheless the secretion of epinephrine by the adrenal medulla, as indirectly estimated by the ratio of the basal urinary elimination to the recovery percentage from the urine of an epinephrine infusion, shows a significant decrease (- 36%) during the protein diet. Thus the enhanced lipolysis does not result from an adrenergic overactivity but merely depends upon the marked reduction in the plasma insulin level (- 38%).

Adrenal Medulla↗
PubMed1980

[Clinical, biological, histological, ultrastructural and therapeutic studies in one case (author's transl)].

The diagnosis of glucagonoma was made in a 51 year-old woman who suffered from a polymorphous dermatitis and an insulin-dependent diabetes mellitus. Denutrition was present and there was a previous history of thrombo-embolism. Immunoreactive plasma glucagon was constantly higher than 1 000 pg/ml (N less than 175). Plasma aminoacids were low. After angiographic confirmation, the tumour and part of its hepatic metastases were resected. The dermatitis disappeared soon after. Its recurrence required chemotherapy (successively mithramycin, streptozotocin, DTIC) and good clinical results were obtained. On histological examination, the cutaneous lesions consisted of an epidermal edema, and a bullous intra-epidermic detachment. The pancreatic tumour was of the trabecular type with a very important sclerosis. On electron microscopy, the tumoral cells, some with a syncitial aspect, contained granules of the D1 type. These granules are different from the typical glucagon granules. The clinical and biological features in this case are compared with those of the 41 cases of glucagonoma previously published.

Adenoma, Islet Cell↗
PubMed1980

Peripheral insulin in response to the sight and smell of food.

Twenty-five obese and 23 reference women were compared with respect to their peripheral insulin concentrations in response to the sight and smell of food. An additional 21 obese women were examined for different control purposes. The women were examined after fasting for approximately 16 hr. Venous blood samples for determination of glucose and insulin were drawn 20, 10, and 1 min prior to the demonstration of food for 5 min. After the food had been presented to the subjects, samples were drawn at 1, 2, 3, 4, 5, 6, 10, 15, and 20 min. The response was calculated in two different ways: method I--the difference between meal basal insulin values and mean insulin values during and/or after stimulation, and method II--the "insulin area" over the mean basal concentration was calculated for 0-20 min after start of food presentation. Both methods resulted in significantly higher insulin responses in obese as compared to reference subjects. However, when performing duplicate experiments in the same subjects only method II resulted in reproducible results and even with this method the error was as high as 60%-90%. The high error of the method was partly expected since the insulin elevation is most likely not only a function of controlled external cues but also dependent on unknown sensorimotor and cognitive-affective alterations. No insulin response was observed when obese women were exposed to an external cue that was not food related. Atropine completely blocked the insulin elevation in response to food related external stimuli indicating that this insulin response is mediated via vagus.

Adult↗