Failure of thiamphenicol in a penicillin-allergic patient with Listeria meningoencephalitis--delayed cure following penicillin desensitization.

A 27-year-old woman, without compromised immunodefenses, experienced a Listeria meningoencephalitis, with brainstem symptoms. The identified agent exhibited poor susceptibility to usual effective antibiotics, except for penicillins. Knowledge of past history of an allergic reaction to beta-lactam antibiotics lead to appropriate therapy after acute intravenous desensitization of the patient to amoxicillin. Treatment resulted in therapeutic administration rate over 24 h, and in rapid regression of clinical and biological disorders.

Fatty acid composition and kinetic behaviour of liver retinyl esters in vitamin A sufficient and deficient rats.

Weanling rats were fed vitamin A deficient diets (-A) or diets supplemented with vitamin A (+A) (4.4 mg retinol equivalents/kg diet) for a period of 7 or 6 wk, respectively. In liver tissues of these two groups of animals both the subcellular localization as well as the fatty acid composition of the retinyl esters was studied. During vitamin A supplementation or deprivation, the kinetics of the different ester forms were investigated. Results indicate that the subcellular localization of all retinyl esters is similar and dependent on age. Two pools exist, ie one consisting of the nuclear/cell debris and mitochondrial-lysosomal fractions and the other containing the microsomal and cytosol fractions. HPLC analysis showed retinyl palmitate as the predominating (80%) form of the various retinyl esters. By supplementation clearly two kinetic behaviours can be demonstrated: one being a relatively stable storage of the palmitate and stearate, increasing with time and the second one being a more labile pattern for the ester forms with other saturated and unsaturated fatty acids. By vitamin A depletion all retinyl esters are affected indicating that the ester forms other than palmitate and stearate are also storage forms of vitamin A.

Zinc deficiency and lymphocyte subpopulations. A study by flow cytometry.

Zinc deficiency is well known to alter immunity. We report the case of a 18-yr-old female with relapsing Crohn's disease who experienced acrodermatitis enteropathica due to zinc deficiency during total parenteral nutrition (TPN). Blood lymphocytes have been studied by flow cytometry: before zinc treatment an important decrease of T-helper lymphocytes with high level of OKM-5+ lymphocytes had been observed. Zinc-supplemented diet induced within a few days, a rise of T-helper lymphocytes and a proportional reduction of OKM5+ cells. Increased values of high metabolism surface marker (OKT-9) were also observed, as well as cytoplasmic modifications. The authors suggest that lymphocyte surface markers could be useful to monitor TPN in patients at high risk for zinc deficiency.

Effects of retinoic acid on hepatic cytochrome P-450 dependent enzymes in rats under different vitamin A status.

The temporal effects of retinoic acid supplementation on hepatic cytochrome P-450-dependent enzymes were studied on the rat. Four groups of male weanling rats were fed semi synthetic diets: two groups containing 0 or 4.4 mg retinol equivalents per kg diet as retinyl palmitate (A- RA- and A+ RA- groups) and two similar groups supplemented with all trans retinoic acid (12 mg/kg diet) (A- RA+ and A+ RA+ groups). After five or ten weeks of feeding, the rats were killed, liver microsomes were prepared and assayed for aniline hydroxylase, aminopyrine N demethylase activities and cytochrome P-450 levels. Whereas no change was observed between the four groups after 5 weeks, the following modifications appeared after 10 weeks: Vitamin A deficiency decreased hepatic drug metabolism by phase I enzymes (hydroxylase and N demethylase) but only when liver storage pool was not detectable. Vitamin A concentration as low as 4 micrograms/g is sufficient to avoid any perturbation of these enzymes. Parallel to a sparing effect on liver reserves of vitamin A, retinoic acid maintained a normal activity of enzymes of xenobiotic metabolism. However, retinoic acid treatment produced an alteration of phase I enzymes in vitamin A supplemented group (A+ RA+). As this was accompanied by a doubling of vitamin A liver reserves, compared to A+ RA- group, it is suggested that this might result from a liver vitamin A overloading, leading to membrane damage perturbing microsomal enzymes. These results indicate the need for a more careful use of retinoids as a therapeutic agent.

Evidence for two subcellular pools and different kinetic behaviour of retinyl palmitate in rat liver.

Rats were fed vitamin A deficient diets (-A) or supplemented with vitamin A (+A) (4.4 mg retinol equivalents/kg diet), either without (-RA) or with retinoic acid (+RA) (12 mg/kg diet) supplementation for up to six weeks. Plasma and liver levels as well as the subcellular localization of vitamin A were determined. In rats reared on the vitamin A rich diet the localization of retinyl palmitate (principal reserve form) is shown to be dependent on age. Two pools exist, i.e. one consisting of the nuclear and mitochondrial-lysosomal fractions and the other containing the microsomal and cytosol fractions. A rapid replenishment of mitochondrial-lysosomal fractions occurs in the first weeks after the weaning. During six weeks of deficient diet an identical mobilization was seen from the different subcellular fractions. Supplementation with RA caused an immediate and sustained reduction of serum vitamin A levels but did not disturb the subcellular localization of retinyl palmitate. A relationship between these phenomena and the subcellular distribution of the retinyl palmitate hydrolase (RPH) and the cellular vitamin A binding proteins (CRBP) is likely to exist.