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B Canivet

Publications and source records attributed to B Canivet.

At least 37 records · Page 2Linked to original sources
PubMed1985

The endosomal compartment of rat hepatocytes. Its characterization in the course of [125I]insulin internalization.

When freshly isolated hepatocytes are incubated with [125I]insulin in the presence of the microtubule-disrupting agent colchicine, internalization of the labelled hormone is not significantly altered. However, the drug limits the endocytosis of the labelled material to a peripheral band of cytoplasm extending 1 micron beyond the plasma membrane. Both in the presence and absence of colchicine, internalized [125I]insulin preferentially associates with clear vesicles (endosomes) and lysosome-like structures, but the relative amount of labelled material associated with clear vesicles is higher in the presence of the drug than in its absence. An inverse pattern is observed for the lysosome-like structures. As demonstrated by cytochemical methods, clear vesicles do not contain the lysosomal enzyme aryl sulfatase. Moreover, colchicine induces an increase of the clear vesicle diameter without affecting their frequency, while it perturbs multivesicular bodies and dense bodies in an opposite way by increasing their frequency without affecting their size. By reducing and/or delaying the fusion between internalized endocytotic vesicles and lysosomes, colchicine allows better characterization of the endosomal compartment of isolated rat hepatocytes and allows it to be distinguished from other compartments, such as multivesicular bodies and the Golgi apparatus.

Animals↗
PubMed1984

[C-peptide in the insulin-dependent diabetic].

Plasma C-peptide levels were measured in classical insulin-dependent diabetics (group I) and in patients who had become insulin-dependent after a mean 12 years of non-insulin dependent diabetes (group II). All had been under insulin therapy for no more than 2 years. Metabolic control, as assessed by blood glucose and glycosylated A1C haemoglobin levels, was equally poor in both groups. The doses of insulin required were almost identical, though slightly higher in group II, while C-peptide levels were twice as high in group II patients as in group I patients. These findings suggest that patients with initially non-insulin dependent diabetes are more resistant to insulin than classical insulin-dependent diabetics. This low sensitivity to insulin might be due to age (which was more advanced in our group II patients) or might indicate that these patients still retain a degree of insulin-resistance that is characteristic of non-insulin dependent diabetes.

Adult↗
PubMed1984

Glucose metabolism in experimental hyperthyroidism: intact in vivo sensitivity to insulin with abnormal binding and increased glucose turnover.

The characteristics of the dose response of insulin on the glucose turnover rate and erythrocyte insulin binding parameters were determined in five normal men before and during experimentally induced hyperthyroidism [L-T4 (2 micrograms kg-1 day-1) for 4 weeks with additional L-T3 (1 microgram kg-1 day-1) for the following 3 weeks]. Hyperthyroidism was characterized by significant rises in T3 from 1.92 +/- 0.17 (+/- SEM) to 3.66 +/- 0.17 nmol/liter (P less than 0.01) and resting metabolic rate from 39 +/- 0.7 to 48 +/- 1 watt/m2 (P less than 0.001). While the subjects received a diet adapted to the metabolic rate, blood glucose rose from 3.8 +/- 0.07 to 4.46 +/- 0.11 mmol/liter (P less than 0.05) without a significant change in plasma insulin. During the insulin dose-response study, glucose infusion rates were unaltered by hyperthyroidism, and neither the maximum effect nor the sensitivity to insulin was altered. Glucose turnover rate, measured using [6,6-2H2]glucose as tracer, was determined in the basal state and during the 0.4 mU kg-1 min-1 insulin infusion. In the basal state, it was significantly increased by hyperthyroidism (control, 2.3 +/- 0.1; hyperthyroidism, 3.7 +/- 0.1 mg kg-1 min-1). During the insulin infusion, hepatic glucose production was totally suppressed before T4 and T3 treatment, but was 0.96 +/- 0.39 mg kg-1 min-1 during T4 and T3 treatment. A marked decrease in the insulin binding affinity to erythrocytes was found without a change in the insulin receptor number. In conclusion, glucose metabolism in experimental hyperthyroidism is characterized by 1) increases in basal glucose production and utilization; 2) antagonism between the effect of insulin and hyperthyroidism at the hepatic level; and 3) lack of peripheral insulin resistance in spite of marked alteration in erythrocyte insulin binding affinity.

Adult↗
PubMed1983

[Adsorption of insulin directly added to infusion bottles].

A study of insulin adsorption to infusion system was undertaken in the situation of direct addition of insulin alone in the infusion bottles, with use of 125I-labelled insulin and non labelled insulin. The infusion solutions tested were glucose solutions (5, 10, 15 and 30%). There is an important adsorption of insulin (75%) to the infusion system when the insulin concentration in the solution is low. The effluent insulin is not degraded. The glucose content of the solution does not influence the phenomenon. Adsorption of insulin decreases when the insulin concentration in the solution is increased and a plateau is reached starting from an insulin concentration in the solution of about 400 ng/ml; at higher concentrations, 80 to 90% of insulin that has been initially put in the bottle is recovered. Since the insulin concentrations in the solutions used in clinical practice are higher than 400 ng/ml, this adsorption phenomenon can be neglected and therefore can explain the efficiency of this mode of insulin-therapy. Kinetics of effluent insulin is a plateau, stable all along the infusion. Thus, direct addition of insulin alone into infusion bottles is an efficient and controlled mode of insulin-therapy if a minimal insulin concentration in the infused solution has been reached.

Adsorption↗
PubMed1983

[In vitro glucose consumption in severe hyperleukocytosis. A cause of factitious hypoglycemia].

Following the observation, in a patient with leukemia, of a factitious hypoglycemia that was related to in vitro glucose consumption by leukocytes, a study of glucose fall in vitro in the blood of 17 patients with leukemia of various types and with various grades of leukocytosis was undertaken. Results show that in vitro glucose consumption is linked to the intensity of leukocytes concentration, and is independant of the type of leukocyte. Factitious hypoglycemia may thus frequently occur in patients with high blood leukocyte count. This phenomenon, that was previously described, is again of interest to day because many laboratories do not yet use any more glycolysis inhibitors that partially inhibit it. Indeed, these inhibitors interfere with measures of other biological parameters that are simultaneously determined in autoanalysers.

Adult↗
PubMed1983

[Angiotensin-converting enzyme and diabetes mellitus].

Elevation of serum angiotensin-converting enzyme (ACE) has been reported to occur in 25 p. 100 of diabetic patients. This finding would decrease the specificity of increased ACE level in sarcoidosis. We measured serum ACE in 90 diabetic patients with simultaneous analysis of various parameters including those appreciating the degree of metabolic control. Serum ACE values, observed in diabetics are not different from values measured in controls, respectively 22,3 +/- 6,4 and 21,1 +/- 6,7 U/ml (means +/- SD). Only 5,5 p. 100 of diabetic patients had (slightly) increased serum ACE levels, i.e.: levels above mean +/- 2 SD of values observed in controls. Serum ACE levels were higher in insulin-dependent diabetics: 24,7 +/- 6,7 (n = 34) than in non insulin-dependent diabetics: 20,8 +/- 5,9 (n = 56) (p = 0,01). In the diabetic group, there is a positive linear correlation between serum ACE level and 24h-glycosuria or glycosylated A1c hemoglobin. These are parameters appreciating middle or long-term metabolic control. In the other hand, no correlation was observed between serum ACE and glycemia, triglyceridemia, serum creatinin, blood pressure or the presence of diabetic retinopathy. These findings do not show an elevation of serum ACE in diabetic patients. However, they suggest that long-term metabolic control of diabetes influence serum ACE level.

Diabetes Mellitus↗
PubMed1983

[Adsorption of insulin introduced directly into perfusion bottles].

A study of insulin adsorption to infusion system was undertaken in the situation of direct addition of insulin alone in the infusion bottles, with use of 125I-labelled insulin and non labelled insulin. The infusion solutions tested were glucose solutions (5, 10, 15 and 30%). There is an important adsorption of insulin (75%) to the infusion system when the insulin concentration in the solution is low. The effluent insulin is not degraded. The glucose content of the solution does not influence the phenomenon. Adsorption of insulin decreases when the insulin concentration in the solution is increased and a plateau is reached starting from an insulin concentration in the solution of about 400 ng/ml; at higher concentrations, 80 to 90% of insulin that has been initially put in the bottle is recovered. Since the insulin concentrations in the solutions used in clinical practice are higher than 400 ng/ml, this adsorption phenomenon can be neglected and therefore can explain the efficiency of this mode of insulin-therapy. Kinetics of effluent insulin is a plateau, stable all along the infusion. Thus, direct addition of insulin alone into infusion bottles is an efficient and controlled mode of insulin-therapy if a minimal insulin concentration in the infused solution has been reached.

Adsorption↗
PubMed1982

[Hepatitis and hyperthyroidism (author's transl)].

Two cases of hyperthyroidism with hepatic manifestations are reported. In both the clinical picture was misleading. In one case, hyperthyroidism was responsible for liver involvement. Hépatic manifestations of hyperthyroidism are both polymorphic and non-specific. Diagnosis should be considered only after outruling other possibilities. In the other case, cholestatic hepatitis developed independantly from hyperthyroidism. The resulting clinical picture was confusing. All patients should be checked for non-thyrotoxic liver disease which may be of prognostic and therapeutic significance.

Aged↗
PubMed1982

[In vitro glucose consumption in severe hyperleukocytosis. A cause of factitious hypoglycemia].

Following the observation, in a patient with leukemia, of a factitious hypoglycemia that was related to in vitro glucose consumption by leukocytes, a study of glucose fall in vitro in the blood of 17 patients with leukemia of various types and with various grades of leukocytosis was undertaken. Results show that in vitro glucose consumption is linked to the intensity of leukocytes concentration, and is independent of the type of leukocyte. Factitious hypoglycemia may thus frequently occur in patients with high blood leukocyte count. This phenomenon, that was previously described, is again of interest to day because many laboratories do not yet use any more glycolysis inhibitors that partially inhibit it. Indeed, these inhibitors interfere with measures of other biological parameters that are simultaneously determined in autoanalysers.

Adult↗
PubMed1981

[Gastric bezoar in diabetes mellitus. 3 cases (author's transl)].

Diabetic gastroparesis is the gastric manifestation of diabetic autonomic neuropathy and may result, on rare occasions, in the formation of a bezoar. This was the case in 3 patients (two women aged 36 and 66 and a 19-year-old man) whose insulin-dependent diabetes was complicated with neuropathy. All patients had marked glycaemic instability apparently related to digestive function. In one patient, a stable normoglycaemic state was obtained by continuous intravenous administration of carbohydrates until the bezoar had disappeared. In the other two patients, who had a long history of neglected digestive disorders, the bezoars provided intractable. In diabetics with dyspeptic symptoms, and particularly when neuropathy is present, it would be advisable to investigate for gastroparesis in order to prevent the development of a bezoar by dietetic and therapeutic measures.

Adult↗