Chronic kidney disease--mineral and bone disorder: a complex scenario.

The chronic kidney disease-bone and mineral disorders (CKD-MBD) represents a dinamic area of research. Recently, new factors such as FGF-23 have been added to the classic list of regulators of bone metabolism, which include calcium, phosphorus, PTH and calcitriol. Vascular calcification, one of the most important complication of CKD-MBD is regulated by a complex variety of  promoters and inhibitors. The relationship between vascular calcification, bone loss and mortality, together with the existence of likely common signaling pathways are subject of interesting investigations.

El complejo escenario de las alteraciones de metabolismo óseo y mineral en la enfermedad renal crónica / Chronic kidney disease-mineral and bone disorder: a complex scenario

Las alteraciones del metabolismo óseo en el escenario de la enfermedad renal crónica (CKD-MBD) constituyen un dinámico campo de estudio. Al conjunto de reguladores clásicos del metabolismo óseo tales como calcio, fósforo, hormona paratiroidea (PTH) y calcitriol se ha añadido el factor de crecimiento fibroblástico 23 (FGF-23). La calcificación vascular, una de las complicaciones más importantes de la enfermedad renal crónica, está sujeta a una compleja regulación en la que intervienen factores promotores e inhibidores del proceso de mineralización. La asociación entre calcificación vascular, desmineralización ósea y mortalidad y la existencia de factores y vías de señalización comunes está siendo objeto de interesantes investigaciones (AU)

The chronic kidney disease-bone and mineral disorders (CKD-MBD) represents a dinamic area of research. Recently, new factors such as FGF-23 have been added to the classic list of regulators of bone metabolism, which include calcium, phosphorus, PTH and calcitriol. Vascular calcification, one of the most important complication of CKD-MBD is regulated by a complex variety of promoters and inhibitors. The relationship between vascular calcification, bone loss and mortality, together with the existence of likely common signaling pathways are subject of interesting investigations (AU)

Socioeconomic impact on device-associated infections in limited-resource neonatal intensive care units: findings of the INICC.

PURPOSE: To evaluate the impact of country socioeconomic status and hospital type on device-associated healthcare-associated infections (DA-HAIs) in neonatal intensive care units (NICUs). METHODS: Data were collected on DA-HAIs from September 2003 to February 2010 on 13,251 patients in 30 NICUs in 15 countries. DA-HAIs were defined using criteria formulated by the Centers for Disease Control and Prevention. Country socioeconomic status was defined using World Bank criteria. RESULTS: Central-line-associated bloodstream infection (CLA-BSI) rates in NICU patients were significantly lower in private than academic hospitals (10.8 vs. 14.3 CLA-BSI per 1,000 catheter-days; p < 0.03), but not different in public and academic hospitals (14.6 vs. 14.3 CLA-BSI per 1,000 catheter-days; p = 0.86). NICU patient CLA-BSI rates were significantly higher in low-income countries than in lower-middle-income countries or upper-middle-income countries [37.0 vs. 11.9 (p < 0.02) vs. 17.6 (p < 0.05) CLA-BSIs per 1,000 catheter-days, respectively]. Ventilator-associated-pneumonia (VAP) rates in NICU patients were significantly higher in academic hospitals than in private or public hospitals [13.2 vs. 2.4 (p < 0.001) vs. 4.9 (p < 0.001) VAPs per 1,000 ventilator days, respectively]. Lower-middle-income countries had significantly higher VAP rates than low-income countries (11.8 vs. 3.8 per 1,000 ventilator-days; p < 0.001), but VAP rates were not different in low-income countries and upper-middle-income countries (3.8 vs. 6.7 per 1,000 ventilator-days; p = 0.57). When examined by hospital type, overall crude mortality for NICU patients without DA-HAIs was significantly higher in academic and public hospitals than in private hospitals (5.8 vs. 12.5%; p < 0.001). In contrast, NICU patient mortality among those with DA-HAIs was not different regardless of hospital type or country socioeconomic level. CONCLUSIONS: Hospital type and country socioeconomic level influence DA-HAI rates and overall mortality in developing countries.

Analgesia multimodal postoperatoria / Postoperative multimodal analgesia

No disponible

Manejo del dolor perioperatorio infantil / Management of pediatric perioperative pain

No disponible

Bloqueo simpático cervical en una complicación de empozoñamiento ofídico por Bothrops: reporte de un caso clínico pediátrico / Cervical sympathetic blockade in a complication of ophidic poisoning by Bothrops: report of a pediatric clinical case

Este caso clínico se refiere a un preescolar, quien fue mordido en la mano derecha por una serpiente perteneciente al género Bothrops. Ingresó a la Unidad de Cuidados Intensivos Pediátricos cinco días después del accidente ofídico, con los siguientes diagnósticos: emponzoñamiento ofídico, sepsis, hemorragia digestiva superior, íleo paralítico, coagulación intravascular diseminada, insuficiencia renal aguda, concomitantemente zonas de necrosis y lisis en mano y antebrazo derecho .Al día siguiente de ingresar, presentó abdomen agudo quirúrgico, se realizó laparotomía exploradora, limpieza quirúrgica del miembro afectado, necrectomía más amputación de falange distal de dedo índice derecho .La analgesia inicial se efectuó con morfina e.v. 8 mg/día durante seis días, luego fentanilo a razón de 1 µg . k g- 1. h- 1.día. Debido necrosis del dedo pulgar se practicó desarticulación del mismo. Persistió cuadro álgido; se incrementó la dosis de fentanilo a 1,5 µg . k g- 1. h- 1. día. A los 8 días de hospitalización es valorado por el anestesiólogo especialista en dolor. La clínica sugirió dolor mantenido por el simpático. Se realizó bloqueo simpático cervical con fines diagnósticos y terapéuticos. Se obtuvo un adecuado control del dolor, realizándose un total de cuatro bloqueos sucesivos, con una evolución satisfactoria. El paciente pudo regresar cuatro días más tarde a una sala general de pediatría (AU)

Crystallization and preliminary X-ray analysis of the formiminotransferase domain from the bifunctional enzyme formiminotransferase-cyclodeaminase.

Formiminotransferase-cyclodeaminase (E.C. 2.1.2.5-E.C. 4.3.1.4) is a bifunctional enzyme involved in the histidine-degradation pathway which exhibits specificity for polyglutamylated folate substrates. The first function of the enzyme transfers the formimino group of formiminoglutamate to the N5 position of tetrahydrofolate, while the second function catalyses the cyclodeamination of the formimino group, yielding N5,10-methenyl-tetrahydrofolate, with efficient channeling of the intermediate between these activities. Initial studies have shown that the enzyme consists of eight identical subunits of 62 kDa each, arranged as a circular tetramer of dimers. It is this formation which results in two different dimeric interfaces, which are necessary for the two different activities. The identical subunits have been shown to consist of two domains, each of which can be obtained as dimers. The formiminotransferase domain has been crystallized in the presence of the substrate analogue folinic acid. The crystals belong to space group P212121, with unit-cell dimensions a = 64.4, b = 103.7, c = 122.3 A. Both a native data set and a mercurial derivative data set have been collected to 2.8 A resolution.

Comparación de los niveles séricos del factor de crecimiento similar a la insulina tipo I en los recien nacidos con peso bajo, normal y alto para la edad gestacional

Para evaluar la relación entre los niveles séricos del factor de crecimiento similar a la insulina tipo 1 (IGF-1) y el peso al nacer en los neonatos, se cuantificaron los niveles séricos del IGF-I en 23 neonatos con bajo peso para la edad gestacional (PBEG), 27 con peso adecuado para la edad gestacional (PAEG) y 27 con peso alto para la edad gestacional (PAEG). El peso al nacer en el primer grupo fue de 1.630ñ 147 gms (MñDS), del segundo fue de 3.108ñ 290gms, y del tercero fue de 4.235ñ 268mgs. Los valores de IGF-I fueron de 0.3ñ 0.08, 47.9ñ 30.4, 104.3ñ 50.1 ng/ml, respectivamente (p<0.0001). Se encontró una correlación significativa entre el peso al nacer y los valores séricos de IGF-I con r=0.7 y p<0.0001. En conclución, hay una relación significativa entre los niveles séricos de IGF-I y el peso al nacer, a mayor peso nivel de IGF-I.

Crystallization of the bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase domain of the human trifunctional enzyme.

Methylenetetrahydrofolate([H4] folate) dehydrogenase (D) and methenyl[H4] folate cyclohydrolase (C) coexist as a bifunctional enzyme (DC) or as the amino-terminal domain of a trifunctional enzyme (DCS) where the third activity is 10-formyl[H4]folate synthetase (S). Two crystal forms of the DC domain of the human cytosolic DCS enzyme have been grown from polyethyleneglycol solution. The monoclinic P2(1) crystals diffract to 2.8 A with a = 72.5 A, b = 68.5 A, c = 125.2 A, and beta = 91.8 degrees but were found to be twinned. The orthorhombic P2(1)2(1)2(1) crystals diffract to 2.5 A with a = 67.7 A, b = 135.9 A, c = 61.6 A, and contain two molecules per asymmetric unit.

The nucleotide sequence of porcine formiminotransferase cyclodeaminase. Expression and purification from Escherichia coli.

We have isolated and characterized cDNA clones encoding the porcine liver octameric enzyme, 5-formiminotetrahydrofolate:L-glutamate N-formiminotransferase (EC 2.1.2.5)-formiminotetrahydrofolate cyclodeaminase (EC 4.3.1.4). The cDNA encodes a novel amino acid sequence of 541 residues which contains exact matches to two sequences derived by automated sequence analysis of CNBr cleavage fragments isolated from the porcine enzyme. The recombinant enzyme has been expressed as a soluble protein in Escherichia coli at levels 4-fold higher than those observed in liver, and is bifunctional, displaying both transferase and deaminase activities. With a calculated subunit molecular mass of 58,926 Da, it is similar in size to the enzyme isolated from porcine liver. Purification of the enzyme from E. coli involves chromatography on a novel polyglutamate column which might interact with the folylpolyglutamate binding site of the protein. The purified recombinant enzyme has a transferase specific activity of 39-41 units/mg/min.

The NADP-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase is not expressed in Spodoptera frugiperda cells.

The insect cell line derived from Spodoptera frugiperda (Sf9) does not express the activities of the trifunctional NADP-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase. The lack of synthetase activity was confirmed by the inability to incorporate radiolabeled formate into nucleotides. The cells express, instead, a Mg2+ and NAD-dependent bifunctional methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase with properties similar to the enzyme found in the mitochondria of transformed mammalian cells. In contrast, the enzyme in Sf9 cells is localized in the cytoplasm. Nutritional studies in defined medium with dialyzed serum demonstrated that the Sf9 cell does not required added purines or pyrimidines for growth. It is auxotrophic for cysteine and glycine; this latter requirement is probably due to the absence of mitochondrial serine hydroxymethyltransferase. Incorporation of labeled glycine and serine into DNA indicates that only serine is a source of one-carbon units. These results suggest that the mitochondria in Sf9 cells do not play a major role in folate-mediated metabolism.

Prevalence of maternal HIV infection based on unlinked anonymous testing of newborn babies.

This pilot study established that unlinked anonymous testing of dried blood spots routinely collected on Guthrie cards for neonatal screening is a feasible method for monitoring HIV prevalence in women at the time of delivery. The method was sensitive, specific, and less expensive than more conventional ELISAs. 114,515 dried blood spots taken from cards collected in three Thames regions were tested for antibody to HIV-1. 28 samples were confirmed to be antibody positive by western blot (seroprevalence 0.24 per 1000). Unlinked anonymous screening of newborn babies should be extended to monitor the spread of HIV infection in the heterosexual population and to target preventive strategies and provision of health care.

NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase in transformed cells is a mitochondrial enzyme.

Transformed mammalian cells express a unique bifunctional NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase in addition to the usual NADP-dependent dehydrogenase-cyclohydrolase-synthetase. Subcellular fractionation of murine cell lines revealed that the NAD-dependent dehydrogenase activity is located predominantly in mitochondria, while the NADP-dependent trifunctional dehydrogenase appears to exist only in the cytosol of these cells. Western analysis using monospecific polyclonal antisera confirms the subcellular distribution of these two proteins.

Methylenetetrahydrofolate dehydrogenases in normal and transformed mammalian cells.

Transformed mammalian cells express both the usual NADP-dependent trifunctional methylenetetrahydrofolate dehydrogenase-cyclohydrolase-synthetase as well as the bifunctional NAD-dependent methylenetetrahydrofolate dehydrogenase-cyclohydrolase. Antisera to these proteins do not crossreact, and Western blots of cell extracts indicate that there is no inactive form of the NAD-dependent enzyme in normal tissues. Immunofluorescence studies suggest a cytosolic location for the NAD-dependent enzyme, although sequence homology seen in the N-terminal 10 residues indicates a closer relationship with the mitochondrial form of the yeast NADP dependent trifunctional enzyme.

The NADP-dependent trifunctional methylenetetrahydrofolate dehydrogenase purified from mouse liver is immunologically distinct from the mouse NAD-dependent [corrected] bifunctional enzyme.

Methylenetetrahydrofolate dehydrogenase - methenyltetrahydrofolate cyclohydrolase - formyltetrahydrofolate synthetase was purified to homogeneity from mouse liver, taking advantage of its very high affinity for 2',5'-ADP-Sepharose. Antibodies raised to this trifunctional enzyme and to the bifunctional NAD-dependent dehydrogenase-cyclohydrolase from mouse Ehrlich ascites tumour cells were found not to cross-react with the purified proteins on Western blots. Each of these polyclonal antibodies detects the appropriate protein in extracts of Ehrlich ascites tumour cells after sodium dodecyl sulfate - polyacrylamide gel electrophoresis and electrophoretic transfer of the proteins to nitrocellulose. The procedure has also been used to obtain a purified preparation of the trifunctional enzyme from human liver obtained at autopsy.

NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase from ascites tumor cells. Purification and properties.

NAD-dependent methylenetetrahydrofolate dehydrogenase is expressed in transformed or established mammalian cell lines in vitro but only in the developmental tissues of normal adult animals (Mejia, N. R. and MacKenzie, R. E. (1985) J. Biol. Chem. 260, 14616-14620). The enzyme, which contains methenyltetrahydrofolate cyclohydrolase activity as well, has been purified 6000-fold from Ehrlich ascites tumor cells. The preparation is homogeneous by sodium dodecyl sulfate gel electrophoresis (Mr = 34,000), and results from cross-linking with bis(sulfosuccinimidyl)suberate are consistent with a dimeric structure (Mr = 68,000) for the native bifunctional enzyme. The dehydrogenase is specific for NAD and requires both a divalent cation, Mg2+ or Mn2+, for activity and as well is stimulated by inorganic phosphate. When compared to the usual NADP-dependent methylenetetrahydrofolate dehydrogenase from mouse liver, the NAD-dependent dehydrogenase activity of the murine tumor enzyme shows a greater affinity for the polyglutamate forms of folate.

NAD-dependent methylenetetrahydrofolate dehydrogenase is expressed by immortal cells.

An enzyme activity not detected in normal cells is expressed in embryonic, undifferentiated, or transformed cells. Twenty-one established mammalian cell lines, both tumorigenic and nontumorigenic, were found to have an NAD-dependent methylenetetrahydrofolate dehydrogenase (Scrimgeour, K.G., and Huennekens, F.M. (1960) Biochem. Biophys. Res. Commun. 2, 230-233) in addition to the well-characterized NADP-specific activity. The NAD-dehydrogenase in cell extracts can be separated from the NADP activity by column chromatography. Normal adult tissues including brain, heart, skeletal muscle, liver, and kidney contain the NADP but not the NAD activity. Only normal tissues which contain differentiating cells such as bone marrow, thymus, spleen, and embryonic liver contain the NAD activity. The distribution of the NAD enzyme suggests that it could be useful as an oncodevelopmental marker. Its physiological role is unknown, but it is proposed that it promotes purine synthesis and perhaps contributes to the methionine dependence and rapid growth observed for many established lines.