Hydroelectrolytic and infectious complications in one year of parenteral nutrition in critical care. / Complicaciones hidroelectrolíticas e infecciosas en un año de nutrición parenteral en cuidados críticos.

OBJECTIVE: Parenteral nutrition consists of the intravenous administration of macronutrients, micronutrients and electrolytes. Our objectives were to evaluate the biochemical alterations during the first ten days of initiation and to quantify the bacteremia related to the central venous catheter during the administration of parenteral nutrition. MATERIAL AND METHODS: Retrospective study of incidence and prevalence. We included 51 patients who started intravenous nutritional support therapy at Critical Care. We intend to know the infectious complications of the central line associated with parenteral nutrition, to evaluate the most frequent hydroelectrolytic complications of parenteral nutrition, and to identify minimum control points in the detection of hydroelectrolytic alterations. RESULTS: Statistically significant daily variations were found for glucose, magnesium, potassium and creatinine, and bordering on the statistical significance for albumin and phosphate, the alterations occurring between the second and third days fundamentally. Hypoalbuminemia and hypocalcemia were very frequent. GGT was the liver enzyme that increased more frequently. The infection rate was 14.86 per 1,000 days of central venous catheter. CONCLUSIONS: We found daily variations in glucose, potassium and magnesium, as well as a decrease in creatinine. We emphasize the frequency of hypoalbuminemia, hypocalcemia and elevation of GGT. The most important variations occurred between the second and third day, highlighting the precocity of potassium alteration and the peak of glycemia. The rate of infection related to the central venous catheter in patients with parenteral nutrition was high.

Progesterone and the oligodendroglial lineage: stage-dependent biosynthesis and metabolism.

Evidence has been accumulated showing that neurosteroids, particularly progesterone (PROG) and its metabolites, may participate in myelination and remyelination in the peripheral nervous system, but very few studies have been undertaken in the central nervous system (CNS). The aim of this work was to investigate the capacities of synthesis and metabolism of PROG at three important stages of the oligodendroglial lineage: oligodendrocyte pre-progenitors (OPP), oligodendrocyte progenitors (OP), and fully differentiated oligodendrocytes (OL). Experiments have been conducted in vitro using highly purified primary cell cultures from rat brain. Cells were incubated with (3)H-pregnenolone ((3)H-PREG), the immediate precursor of PROG, or with (3)H-PROG, and steroids metabolites were then identified by thin layer chromatography and high-performance liquid chromatography (HPLC). mRNA expression of key steroidogenic enzymes was evaluated by reverse transcription-polymerase chain reaction (RT-PCR). The results showed that only OPP and OP, but not OL, expressed 3 beta-hydroxysteroid dehydrogenase/Delta 5-Delta 4 isomerase mRNA and were able to synthesize PROG from PREG. In the three cell types studied, PROG was metabolized by the type 1 isoform of 5 alpha-reductase into 5 alpha-dihydroprogesterone (5 alpha-DHPROG). This enzyme exhibited a 5-fold higher activity in OL than in OPP and OP. 5 alpha-DHPROG was further transformed either into 3 alpha,5 alpha-tetrahydroprogesterone (3 alpha,5 alpha-THPROG), known as a positive allosteric modulator of the GABA(A) receptor, or into the 3 beta-isomer. The 3 alpha,5 alpha-THPROG synthesis was 10 times higher in OPP than in the other cell studied, while the 3 beta,5 alpha-THPROG production did not change with cell differentiation. PROG synthesis and metabolism and the dramatic changes in neurosteroidogenesis observed during the oligodendroglial differentiation may contribute to oligodendrocyte development or the myelination process.