[Biochemical and pharmacological check-up in emergency orientation]. / Bilans biochimiques and pharmacologiques d'orientation en urgence.

Biochemical and pharmacological tests usually prescribed in casualty department were reviewed taking into account their physiological significance and predictive value : ions, total proteins, carbohydrate and nitrogenous metabolites, enzymes, tissue markers, pharmacological drugs. Few blood components were kept with the first intention, ideally with a turn around time below one hour: sodium, potassium, chloride, bicarbonate, total proteins, pCO2 and pO2, creatinine, glucose, ketone compounds, calcium, bilirubin, transaminases, lipase, C-reactive protein, myoglobin, troponin, chorionic gonadotropin hormone. Those tests do not have to be systematically performed but prescribed only after the evaluation of pre-test probabilities by the clinician.

[Contribution of molecular biology to the diagnosis of familial hypercholesterolemias in children]. / Apport de la biologie moléculaire au diagnostic des hypercholestérolémies familiales chez l'enfant.

The detection of children at high risk in families with a genetic form of hypercholesterolemia is important for acceptance of prevention under medical control. However, usual lipidic parameters are difficult to interpret during infancy. So we studied by a molecular biology approach 11 families presenting with syndrome of pure hypercholesterolemia where a defect of the LDL receptor (LDL-R) gene was suspected (Familial Hypercholesterolemia: FH IIa). Markers of the LDL-R gene (Restriction Fragment Length Polymorphism RFLP) were studied with intragenic probes. The segregation of the abnormal gene was studied in each family. Our results illustrate the limits of such an approach (its heaviness and the fact that, in 2 families, the analysis was not informative), but also its advantages: indeed, in 8 families, the diagnosis was established (particularly in one case at birth). Moreover in 2 families the LDL-R abnormality was excluded. In such case, as an alternative, the hypothesis of an apo B abnormality was envisaged. This differential diagnosis is interesting since it permits the choice of an adequate treatment.

[Recurrent rhabdomyolysis and deficiency of carnitine palmityl transferase. Evidence of the responsibility of a mutant in 2 brothers]. / Rhabdomyolyse récidivante et déficit en carnitine palmityl transférase. Preuve de la responsabilité d'un mutant chez 2 frères.

In two brothers who had been presenting since childhood with intermittent muscular attacks and myoglobinuria after sustained efforts, muscle carnitine palmityl transferase (CPT) activity was undetectable by the backward hydroxamate colorimetric method. Such a total deficiency could not easily fit in with the clinical features (normal muscular activity outside sustained efforts), with the normal results obtained at electromyography and with the moderate fatty overload detected at muscle biopsy. In order to elucidate these apparently discordant findings, another CPT measurement method, the forward optimized isotopic technique, was used. With this method, the catalytic activity of CPT can be measured, and enzyme inhibition by its substrate and the product of the reaction (palmityl CoA and palmitylcarnitine respectively) can be studied. The results showed that the catalytic activity of CPT was preserved in both patients, but the enzyme was abnormally sensitive to inhibitors. These 2 cases tend to demonstrate the existence of a mutant carnitine palmityl transferase.

[Isoenzymes of N-acetyl-beta-D-glucosaminidase (NAG): new method of evaluating the nephrotoxicity of aminosides. Our experience with dibekacin in geriatrics]. / Les isoenzymes de la N-acétyl-bêta-D-glucosaminidase (NAG): une nouvelle méthode d'évaluation de la néphrotoxicité des aminosides. Notre expérience avec la dibékacine en gériatrie.

To evaluate nephrotoxicity of dibekacin among elderly patients, we studied the daily urinary excretion of NAG and determined isoenzyme levels in the urine of 36 patients (mean age 80 yrs) treated with dibekacin (3 mg.kg-1.day-1). Only two patients developed transient acute renal failure during the first 10 days of treatment. Total NAG urinary activity was however important (304.5 +/- 38.6 U/mmol creat), due primarily to isoenzymes A (58.8 +/- 2.0%) and I (30.8 +/- 1.5%), while B-form excretion was moderately increased (10.3 +/- 1.0%). These results were compared with those obtained with gentamicin (28 patients, 11 transient acute renal failure). The rate of A-form was identical for both antibiotics while excretion of the B-form was significantly higher with gentamicin (p less than 0.001). These results show that nephrotoxic risk is linked to the excretion of the B-form, and allow us to oppose the notion of "functional" enzymuria (low nephrotoxic risk) linked with A- and I-forms with the notion of "lesional" enzymuria (high nephrotoxic risk) linked with the B-form.