Biomedical subjects
Publications and source records attributed to J Aubertin.
In a patient with Waldenström's macroglobulinaemia and peripheral neuropathy, direct immunofluorescence of a peripheral nerve revealed the presence of abundant IgM and kappa light chain deposits in the endoneurium. Electron microscopic examination showed the microtubular structure of these endoneurial deposits, which strongly suggested the presence of cryoglobulin; this was then found in the serum.
Systolic left ventricular function was investigated by echocardiography in 23 young, type 1 diabetics and 11 control subjects. A stimulation by isoproterenol was performed in order to study beta-adrenergic cardiac responsiveness. M-mode recordings were digitized and analyzed by computer. Systolic parameters such as left ventricular fractional shortening and mean velocity of circumferential shortening were not different, but maximal velocity of shortening was increased both at rest (P less than 0.01) and with isoproterenol (P less than 0.05) in the diabetics. An abnormal systolic anterior motion of the mitral valve was found during administration of isoproterenol in 65% of the diabetics and in only one control. These findings are suggestive of a hyperkinetic state, associated with a poor metabolic control (high value of HbA1), together with adrenergic hypersensitivity in type 1 diabetes mellitus.
Tissue insulin sensitivity was measured by the glucose clamp technique in 8 uremic insulin-dependent diabetic patients before and after 3 months on a low-protein diet (LPD) providing daily 35 kcal/kg body weight, 60% of the caloric supply being obtained from carbohydrates. An improvement in tissue insulin sensitivity was observed for each steady state of the clamp and daily insulin requirements decreased significantly from 38.3 +/- 3.2 to 28.2 +/- 2.5 units (p less than 0.01) in spite of an increased carbohydrate intake. It is suggested that LPD lowers the production and accumulation of uremic toxins interfering with insulin sensitivity.
We report the cases of 4 male subjects, 29, 32, 41 and 44 years old, presenting isolated seropositivities for the human immunodeficiency virus (HIV), or full-blown acquired immunodeficiency syndrome, associated with a typical porphyria cutanea tarda (PCT). The 4 patients are in the usual risk groups for HIV infection. Viral hepatitis was observed in 3 of the 4 cases. Over the past 3 years, 15 cases associating HIV infection and PCT have been reported; almost all had the usual risk factors for HIV infection and hepatopathy. We speculate that HIV infection may have favored the occurrence of early PCT in these cases by altering the metabolism of the porphyrins, either directly or by means of the associated hepatopathy.
The role of metformin on platelet aggregation was studied in subjects affected by relatively well controlled type 1 diabetes. 1700 mg of metformin were added to their usual daily treatment; nothing else was changed. Patients were trained to monitor their own glycaemia and presence of degenerative retinopathy was proved. Before the administration of metformin and on day 21, the platelet induced by 1.25, 2.5 and 5 mumol of ADP and by collagen was studied. Fibrinogen, cholesterol, triglycerides, glycosylated haemoglobin and mean blood glucose levels did not show any significant modification after treatment but the maximum aggregation induced by ADP was significantly decreased; the inhibition of aggregation was particularly sensitive for low doses of ADP. No significant correlation was found between the variations in metabolism data and the reduction of the amplitude of platelet aggregation. Metformin, added to the usual treatment undergone by a diabetic treated with insulin, seems to affect platelet aggregation independently of other metabolic factors.
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Dietary fibre and biproducts of some vegetable extracts (Guar etc.) are advocated to reduce postprandial hyperglycaemia but there is some evidence that these may disturb the absorption kinetics of orally administered drugs. The effect of Guar gum on the digestive absorption of metformin was tested in 6 healthy subjects given 1700 mg of metformin with a standardised meal. Metformin blood levels showed that when given together with Guar there was a reduction in the absorption rate over the first 6 hours. These findings suggest that combination therapy may diminish the anti-hyperglycaemic action of metformin.
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Effects of a low protein (0.3 g/kg/day) diet on glucose tolerance and tissue insulin sensitivity were studied in 25 non-diabetic and eight insulin-dependent diabetic uremic patients before and three months after dietary treatment. Carbohydrates accounted for 65% of the caloric intake in the first group and 57% in the second. In the first group, a 50 g oral glucose tolerance test showed that after three months blood glucose was significantly reduced at T60 (P less than 0.05) and serum insulin at T0, T30 (P less than 0.05) and T60 (P less than 0.02). Ten patients of the first group underwent an euglycemic, hyperinsulinemic clamp study; the tissue sensitivity to insulin index of all three clamp periods improved (P less than 0.01 for the first and second, P less than 0.02 for the third). Five patients in the second group underwent a euglycemic clamp study; glucose metabolism increased with each clamp period. Concomitantly, their daily insulin requirements decreased from 37.2 +/- 3.1 to 24.8 +/- 2.7 U/day (P less than 0.05). This conspicuous improvement observed in both groups might be related to a decrease in uremic toxin(s) derived from protein intake. Beneficial results on atherosclerosis and cardiovascular pathology may occur from the reduction of hyperinsulinism.
A case of Actinobacillus ureae meningitis in a 52 year old man with an history of chronic sinusitis and previous skull fractures is reported. Actinobacillus ureae, called for a long time Pasteurella ureae, is a rare cause of meningitis as shown by a short review of the literature (eight cases reported). We have searched the bacteria in the rhinopharynx of the patient's four dogs: this search was unsuccessful in agreement with the literature data which has not yet established an animal host for Actinobacillus ureae.
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Sodium plasma level was followed every three months in 70 non insulin dependent diabetic patients; 112 prescriptions were performed. Five different oral hypoglycemic drugs were used but patients were taken no more than one drug in the same time. 21% of prescription were associated with a low sodium plasma level but it was beneath 129 meq in only 8% of them; a low sodium plasma level was observed with every oral hypoglycemic agent; when the drug was interrupted a normal sodium plasma level was restored; when patients were put under another agent, hyponatremia did not recidive. 67% of patients were free of any symptom. Interference with biological parameters, age of the patients, duration of diabetes and other therapy are studied.
The role of fever on cefotaxime disposition was studied in ten hyperthermic patients. Each subject received intravenously 1 g of cefotaxime on two separated occasions, first when the body temperature was more than 39 degrees C then during a basal state (37 degrees C). Blood samples were taken over 12 hours and urine was collected for 24 hours after injection. After dosing cefotaxime and its metabolite by high performance liquid chromatography, the pharmacokinetic parameters were calculated, especially: plasma and renal clearance, volume of distribution at steady state, area under the curve, and elimination half-life. There is no significant difference in cefotaxime and desacetylcefotaxime disposition between these two states. Hyperthermia has no influence on pharmacokinetics of this cephalosporin.
Over a 24-month period, 274 patients with community-acquired pneumonia were hospitalized in Departments of Medicine at hospitals in Bordeaux, Lyon, Marseille, and Toulouse. Etiology of the pneumonia was determined either by organism identification or by indirect immunofluorescence in only 139 cases (51%). The most frequently isolated etiological agents were Streptococcus pneumoniae (34 cases), Legionella pneumophila (29 cases) and Mycoplasma pneumoniae (24 cases). The majority of patients with legionellosis were male (79%), middle aged (mean age: 53 years), and living in urban areas (69%). Their clinical features were atypical and did not differ from those of other pneumonias. Four patients with legionellosis (13.8%) died. L. pneumophila was isolated directly in only three instances. The study confirms the high prevalence of legionellosis (20%) among pneumonias of identified etiology. The fact that these cases had an atypical clinical presentation and that isolation of the organism was difficult reinforce the need to apply the CDC criteria for the interpretation of positive serological titers.
Ten patients with advanced renal failure (glomerular filtration rate 25 mL/min) were treated with a low phosphorus and low protein diet supplemented with ketoacid analogues. Before starting the diet and four months afterwards, a 50 g oral glucose tolerance test with a three step euglycemic insulin clamp was carried out. A dose-response curve of total body insulin sensitivity was plotted. By the fourth month, glucose tolerance had improved with significantly lower T0, T30, and T60 insulin levels. These results are attributed to the improvement in insulin action as demonstrated by the clamp technique. The dose-response curve had a distinctly higher plateau after dietary treatment, and the tissue sensitivity index to insulin (M/l ratio) was significantly improved. It is suggested that treatment of uremic patients with a low protein diet may reduce levels of a putative insulin inhibitor.
The diagnosis of insulinoma on the basis of persistent hypoglycemia requires further confirmation. The insulin suppression test has been used to support this diagnosis prior to surgical intervention. In this study the euglycemic clamp technique was used to compare five control volunteers with four hypoglycemic patients with suspected insulinoma. Insulin was infused over successive two-hour periods at 2, 4, and 8 mU/kg/min. Plasma glucose levels were clamped at 80 mg/dL (4.4 mmol/L) using an artificial pancreas. High insulin levels were measured in all subjects, ranging from 225 +/- 30 microU/mL (1614 +/- 215 pmol/L) to 1018 +/- 239 microU/mL (7304 +/- 1714 pmol/L). Levels of C peptide fell to 0.1 ng/mL (0.028 nmol/L) in control subjects but remained at high levels in the patients. Insulinoma was confirmed on laparotomy in all four patients. In two patients tested after removal of the tumor the results were found to have returned to normal.