A patient with neurological symptoms and abnormal leukotriene metabolism: a new defect in leukotriene biosynthesis.

A 15-year-old male patient presented with mental retardation, mild motor impairment, and partial deafness. Biochemical investigations showed an abnormal urinary profile of leukotrienes. Concentration of leukotriene D(4) (LTD(4)), which is usually not detectable, was highly increased, whereas LTE(4), the major urinary metabolite in humans, was completely absent.

Elevated plasma cysteinylglycine levels caused by cilastatin-associated antibiotic treatment.

Imipenem (thienamycin formamidine), a broad-spectrum beta-lactam antibiotic, is always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin might cause an accumulation of the aminothiol cysteinylglycine. We demonstrate here that when patients are treated with imipenem-cilastatin, their plasma levels of cysteinylglycine are significantly and specifically increased, while cysteine levels are decreased and homocysteine levels are unaffected.

Determination of plasma amino acids by fluorescent derivatization and reversed-phase liquid chromatographic separation.

Amino acid analysis in physiological fluids remains expensive, as it usually requires a dedicated analyzer. We modified an RP-HPLC method originally devoted to peptide and protein hydrolysate analysis in order to apply it to plasma amino acid determination. The described method uses a commercial kit based on 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate derivatization followed by reversed-phase high-performance liquid chromatography.

Does oxidative stress alter quadriceps endurance in chronic obstructive pulmonary disease?

The role of exercise-induced oxidative stress in the reduced quadriceps endurance of chronic obstructive pulmonary disease (COPD) patients has never been shown. We conducted a randomized, double-blind, and crossover study in which nine severe patients performed localized dynamic quadriceps endurance tests at 40% of maximal strength after oral treatment with the antioxidant, N-acetylcysteine (NAC), and placebo. Venous blood was sampled before, immediately after exercise, and 6 hours later.

Evaluation of cardiovascular risk factors in HIV-1 infected patients using carotid intima-media thickness measurement.

Background: Highly active antiretroviral therapies (HAART) in HIV-infected patients are often associated with lipodystrophy syndrome and metabolic disorders. Atherogenic lipid profile could expose these patients to atheromatous cardiovascular disease. We describe carotid artery intima-media thickness (IMT), a surrogate marker of atherosclerosis, according to HIV status, antiretroviral treatment, lipodystrophy and conventional cardiovascular risk factors.

Red blood cell methylfolate and plasma homocysteine as risk factors for venous thromboembolism: a matched case-control study.

Background: Moderate hyperhomocysteinaemia is a risk factor for venous thromboembolism. We do not know whether this risk depends on homocysteine itself or on components of the homocysteine remethylation pathway, such as methylfolate. We did a case-control study to analyse the relation between the major components of the homocysteine remethylation pathway and risk of venous thromboembolism.