Effect of CYP3A4, CYP3A5, MDR1 and POR Genetic Polymorphisms in Immunosuppressive Treatment in Chilean Kidney Transplanted Patients.

Cyclosporine (CsA) and tacrolimus (TAC) are immunosuppressant drugs characterized by a narrow therapeutic range and high pharmacokinetic variability. The effect of polymorphisms in genes related to the metabolism and transport of these drugs, namely CYP3A4, CYP3A5, MDR1 and POR genes, has been evaluated in diverse populations. However, the impact of these polymorphisms on drug disposition is not well established in Latin American populations. Using TaqMan® probes, we determined the allelic frequency of seven variants in CYP3A4, CYP3A5, MDR1 and POR in 139 Chilean renal transplant recipients, of which 89 were treated with CsA and 50 with TAC. We tested associations between variants and trough and/or 2-hour concentrations, normalized by dose (C0/D and C2/D) at specific time points post-transplant. We found that CYP3A5*3/*3 carriers required lower doses of TAC. In TAC treated patients, most CYP3A5*3/*3 carriers presented higher C0/D and a high proportion of patients with C0 levels outside the therapeutic range relative to other genotypes. These results reinforce the value of considering CYP3A5 genotypes alongside therapeutic drug monitoring for TAC treated Chilean kidney recipients.

Kinesin-1-mediated axonal transport of CB1 receptors is required for cannabinoid-dependent axonal growth and guidance.

Endocannabinoids (eCB) modulate growth cone dynamics and axonal pathfinding through the stimulation of cannabinoid type-1 receptors (CB1R), the function of which depends on their delivery and precise presentation at the growth cone surface. However, the mechanism involved in the axonal transport of CB1R and its transport role in eCB signaling remains elusive. As mutations in the kinesin-1 molecular motor have been identified in patients with abnormal cortical development and impaired white matter integrity, we studied the defects in axonal pathfinding and fasciculation in mice lacking the kinesin light chain 1 (Klc1-/-) subunit of kinesin-1. Reduced levels of CB1R were found in corticofugal projections and axonal growth cones in Klc1-/- mice. By live-cell imaging of CB1R-eGFP we characterized the axonal transport of CB1R vesicles and described the defects in transport that arise after KLC1 deletion. Cofilin activation, which is necessary for actin dynamics during growth cone remodeling, is impaired in the Klc1-/- cerebral cortex. In addition, Klc1-/- neurons showed expanded growth cones that were unresponsive to CB1R-induced axonal elongation. Together, our data reveal the relevance of kinesin-1 in CB1R axonal transport and in eCB signaling during brain wiring.

Synthetic Approaches to Phosphasugars (2-oxo-1,2-oxaphosphacyclanes) Using the Anomeric Alkoxyl Radical ß-Fragmentation Reaction as the Key Step.

The anomeric alkoxyl radical ß-fragmentation (ARF) of carbohydrates possessing an electron-withdrawing group (EWG) at C2, promoted by PhI(OAc)2/I2, gives rise to an acyclic iodide through which a pentavalent atom of phosphorus can be introduced via the Arbuzov reaction. After selective hydrolysis and subsequent cyclization, the phosphonate or phosphinate intermediates can be converted into 2-deoxy-1-phosphahexopyranose and 2-deoxy-1-phosphapentopyranose sugars. The ARF of carbohydrates with an electron-donor group (EDG) at C2 proceeds by a radical-polar crossover mechanism, and the cyclization occurs by nucleophilic attack of a conveniently positioned phosphonate or phosphinate group to the transient oxocarbenium ion. This alternative methodology leads to 5-phosphasugars with a 4-deoxy-5-phosphapentopyranose framework. The structure and conformation of the 2-oxo-1,2-oxaphosphinane and 2-oxo-1,2-oxaphospholane ring systems in different carbohydrate models have been studied by NMR and X-ray crystallography.

A multicenter prospective study of 515 febrile neutropenia episodes in Argentina during a 5-year period.

For better management of patients with febrile neutropenia, our study investigated the epidemiologic, microbiologic, and clinical characteristics of adult inpatients with febrile neutropenia and their mortality-associated factors. To this end, we carried out a prospective, observational, multicenter study in 28 Argentinian hospitals between 2007 and 2012. We included 515 episodes of febrile neutropenia from 346 patients, median age 49 years. Neutropenia followed chemotherapy in 77% of cases, half of the cases due to hematological malignancies. Most episodes were classified as high-risk according to MASCC criteria, and 53.6% of patients were already hospitalized at the onset of febrile neutropenia. Bloodstream infections were detected in 14% episodes; whereas an infectious source of fever was identified in 80% of cases. Mortality rate achieved to 14.95%. The binary regression analysis showed that persistence of fever at day 7, or neutropenia at day 14, dehydration and tachycardia at the onset of febrile neutropenia as well as prior infections were significantly associated with mortality. In addition to expanding our current knowledge on the features of adult patients with febrile neutropenia, present findings provide useful information for better management of them in Argentina, given the appropriate representativeness of centers participating in the study.

Synthesis of chiral ß-iodo- and vinylorganophosphorus(V) compounds by fragmentation of carbohydrate anomeric alkoxyl radicals.

A new general methodology for the synthesis of chiral vinylphosphonate and vinylphosphine oxide carbohydrate derivatives has been developed using the anomeric alkoxyl radical fragmentation reaction as the key step. The synthetic sequence proceeded via ß-iodophosphonate and ß-iodophosphine oxide intermediates, which may be interesting synthons for the introduction of phosphorus into organic molecules. These vinylphosphonates could be easily transformed into 2-methylene-1-phosphapentofuranoses (3-methylene-1,2-oxaphospholanes) and ß-aminophosphonates, isosteres of biologically active α-methylene-γ-lactones and ß-amino acids, respectively.

Synthesis of polyhydroxylated 2H-azirines and 2-halo-2H-azirines from 3-azido-2,3-dideoxyhexopyranoses by alkoxyl radical fragmentation.

The reaction of 3-azido-2,3-dideoxypyranose and 3-azido-2,3-dideoxy-2-halohexopyranose compounds with (diacetoxyiodo)benzene and iodine generated 2-azido-1,2-dideoxy-1-iodoalditols and 2-azido-1,2-dideoxy-1-halo-1-iodoalditols, respectively. These beta-iodo azides could be transformed by chemoselective dehydroiodination into 2-azido-1,2-dideoxy-4- O-formyl-pent-1-enitols and (Z, E)-2-azido-1,2-dideoxy-1-halo-4- O-formyl-pent-1-enitols in good yields. Thermolysis and photochemical studies of these vinyl azides and 1-halovinyl azides for the synthesis of polyhydroxylated 3-alkyl-2 H-azirines and the hitherto unknown 2-halo-3-alkyl-2 H-azirines have also been accomplished.

Fragmentation of carbohydrate anomeric alkoxyl radicals. A new synthesis of chiral beta-iodo azides, vinyl azides, and 2H-azirines.

[reaction: see text] The reaction of 3-azido-2,3-dideoxy-hexopyranose compounds from the d-gluco, d-galacto, d-lacto, and l-arabino carbohydrate series, with (diacetoxyiodo)benzene and iodine, generated 2-azido-1,2-dideoxy-1-iodo-alditols with one carbon less than the starting carbohydrate. These beta-iodo azides could be transformed by dehydroiodination into vinyl azides, which in turn afforded 3-monosubstituted 2H-azirines under thermal conditions. These beta-iodo azides and 2H-azirines may be interesting chiral synthons for the preparation of more complex heterocyclic systems.

Synthesis of phytuberin. 4-endo-tet acid-catalyzed cyclization of alpha-hydroxy epoxides.

The total synthesis of phytuberin, a phytoalexin of the Solanum genus, from (-)-alpha-santonin is reported. The key steps include (a) reductive cleavage of the C-O bond of the gamma-lactone with concomitant protection of the C1 double bond, (b) Sharpless stereocontrolled hydroxy-assisted epoxidation of allylic alcohol 6 and simultaneous deprotection of the C1 double bond, (c) a rare 4-endo-tet acid-catalyzed cyclization of an alpha-hydroxy epoxide, and (d) an unprecedented 4-exo selenocyclization of a homoallylic alcohol.

Tandem beta-Fragmentation-Hydrogen Abstraction Reaction of Alkoxy Radicals in Steroidal Systems.

A number of tertiary or hemiacetalic steroidal alcohols, 2-hydroxy-3,4-dinor-2,3-secocholestan-5-one 2,5-hemiacetal (1), 2beta,3beta-dihydro-3'H-cyclopropa[2,3]-cholestan-5alpha-ol (7), 3beta-phenyl-5alpha-hydroxycholestan-2-one (10), 5alpha-hydroxycholestan-3-one (15), 3beta,5alpha-dihydroxycholestan-7-one 3-acetate (21), and 4,4-dimethyl-19-hydroxy-5alpha-cholestan-3-one 19,3-hemiacetal (27) have been prepared in order to test a new tandem beta-fragmentation-hydrogen abstraction reaction. The alkoxy radicals generated by irradiation of these alcohols with visible light in the presence of (diacetoxyiodo)benzene, iodine, and molecular oxygen undergo a beta-fragmentation reaction followed by peroxidation of the C-radical formed. The peroxy radical reacts further with iodine to give an alkoxy radical and iodoxyl radical (IO(*)). The new alkoxy radical can produce intramolecular functionalization of suitably positioned carbons by hydrogen abstraction through a six-membered cyclic transition state to give tetrahydrofurans or can be intramolecularly trapped by carbonyl groups suitably disposed so as to generate a new alkoxy radical that can afford gamma-lactones by beta-fragmentation.

Cardiomiopatia dilatada en el lactante / Dilatated cardiomyopathy in infants

Se revisan las características clínicas, ECG, Radiológicas y EcoCG de 12 lactantes con Cardiomiopatia dilatada (CD), con un promedio de edad de 9 meses y en un seguimiento desde 1 a 42 meses. El 83% de los pacientes tuvo insuficiencia cardiaca congestiva, soplo sistólico mitral 66%, y el 92% infección respiratoria. El 16% tuvo secuela neurológica por embolía sistémica. Todos tenían alteraciones de la repolarización en el ECG, 75% signos de HVI, 50% crecimiento AI. Un 16% presentó arritmias o bloqueos A-V de primer grado, y en un paciente (8%) se encontró una imagen de pseudoinfarto de pared diafragmática. La radiología mostró Cardiomegalia en el 100%, con relación C/T media de 0,68; en el 66% de los casos había signos sugerentes de hipertensión venocapilar pulmonar. El EcoCG Modo M mostró dilatación VId (x:47,4 mm), disminución de la fracción de acortamiento (FA) (x:13,2%), y aumento de la relación de intervalos sistólicos de aorta (x:0,5). Durante el seguimiento, un 25% ha fallecido, y los que sobreviven aunque han mostrado una mejoría clínica, radiológica y ECG, siguen presentando dilatación VI (x:51.0 mm) y disminución de FA (x:14,4%) en el EcoCG de control. Se concluye que la CD es una patología de mal pronóstico y que el EcoCG es un bueno procedimiento para su diagnóstico, y seguimiento en nuestro medio