Aspectos metabólicos y multivitamínicos del maíz

La deficiencia de vitamina A causa 2.2 millones de muertes al año. Por tanto, investigadores intentan elevar el contenido de β-caroteno y otros carotenoides en cereales mediante la ingeniería genética. Mi trabajo consistió en analizar carotenoides en maíz y callos de arroz transgénico con el fin de indentificar y cuantificar estos pigmentos y además analizar la ruta metabólica de los mismos. Por tal motivo, desarrollaré una técnica analítica por HPLC y UHPLC que me permitió separar la mezcla de carotenoides. Estas moléculas se detectaton utilizando un detector de arreglo de diodos y masas. Con éste último se probaron distintas técnicas de ionización (ESI, APCI y APPI) para encontrar la mejor técnica que ionizara carotenos y xantófilas. Además se hallaron transiciones para identificar a cada uno de los carotenoides. Para mostrar la confiabilidad del método analítico, realicé la validación del mismo y determiné factores importantes que influyen en el análisis de carotenoides, como por ejemplo, su estabilidad química. Para analizar la ruta metabólica de los carotenoides, se realizaron distintos experimentos, entre ellos, introducir distintas combinaciones de genes en el maíz y arroz que permitieran entender cuáles eran las enzimas importantes que permitían la acumulación de carotenoides. También se analizó la biosíntesis de carotenoides a distintas etapas del desarrollo de la semilla de maíz, desde los 15 días después de la polinización (DAP) hasta los 60 DAP y su estabilidad química a lo largo de todo este período. Finalmente, se profundizó en la identificación de nuevos carotenoides encontrados en las muestras, como los oxo-carotenoides (utilizados en la industria como colorantes). Para llevar acabo su identificación, se realizaron pruebas químicas, se determinaron sus espectros visibles y sus fragmentos por masas.   

Replacement therapy for iron deficiency improves exercise capacity and quality of life in patients with cyanotic congenital heart disease and/or the Eisenmenger syndrome

La teràpia suplementària de ferro millora la capacitat d’exercici i la qualitat de vida en malalts amb una cardiopatia congènita cianòtica i/ o síndrome d’Eisenmenger El dèficit de ferro és una troballa comú en la cardiopatia congènita cianòtica, i pot ser la causa d’una reducció en la capacitat d’exercici. Actualment, està indicada la reposició dels dipòsits de ferro en aquest grup de malalts, éssent les evidències científiques escasses. En el present treball investiguem la seguretat i eficàcia del tractament amb ferro en malalts amb una cardiopatia congènita cianòtica. Per tal motiu, vint-i-cinc malalts amb una cardiopatia congenita cianòtica i dèficit de ferro van ser inclosos de forma prospectiva entre Agost del 2008 i Gener del 2009. El tractament utilitzat fou fumarat ferròs oral, fins a una dosi màxima de 200 mg tres vegades al dia. En l’anàlisi basal i als tres mesos de seguiment es va utilitzar el test de qualitat de vida “CAMPHOR”, el test de la marxa dels 6 minuts i la prova d’esforç amb consum d’oxigen. L’edat mitja fou 39.9+/-10.9 anys, 80% dones. Catorze malalts tenien la síndrome d’Eisenmenger, sis una malaltia cianòtica complexa i cinc circulació de Fontan. Cap d’ells va haver d'interrompre el tractament degut a efectes adversos. Després de tres mesos de tractament, l’hemoglobina (19.0+/-2.9g/dL a 20.4+/-2.7g/dL, p&0.001), ferritina (13.3+/-4.7mug/L a 54.1+/-24.2mug/L, p&0.001) i saturació de transferrina (17.8+/-9.6% a 34.8+/-23.4%, p&0.001) van augmentar significativament. També hi va haver una millora significativa en la puntuació del test de qualitat de vida (20.7+/-10.9 a 16.2+/-10.4, p=0.001) i el test de la marxa (371.7+/-84.7m a 402.8.0+/-74.9m, p=0.001). No es van evidenciar canvis significatius en els valors de consum d’oxigen (40.7+/-9.2% a 43.8+/-12.4%, p=0.15). En definitiva, la teràpia suplementària amb ferro en els malats amb una cardiopatia congènita cianòtica i dèficit de ferro és segura i millora la qualitat de vida i la capacitat funcional. En aquest grup de malalts, per tant, és aconsellable identificar el dèficit de ferro i restaurar-ne els seus dipòsits.

Vitamin E but not 17B-estradiol protect against vascular toxicity induced by B-amyloid wild type and the Dutch amyploid variant

Amyloid β-peptide (Aβ) fibril deposition on cerebral vessels produces cerebral amyloid angiopathy that appears in the majority of Alzheimer's disease patients. An early onset of a cerebral amyloid angiopathy variant called hereditary cerebral hemorrhage with amyloidosis of the Dutch type is caused by a point mutation in Aβ yielding AβGlu22→Gln. The present study addresses the effect of amyloid fibrils from both wild-type and mutated Aβ on vascular cells, as well as the putative protective role of antioxidants on amyloid angiopathy. For this purpose, we studied the cytotoxicity induced by Aβ1–40 Glu22→Gln and Aβ1–40 wild-type fibrils on human venule endothelial cells and rat aorta smooth muscle cells. We observed that AβGlu22→Gln fibrils are more toxic for vascular cells than the wild-type fibrils. We also evaluated the cytotoxicity of Aβ fibrils bound with acetylcholinesterase (AChE), a common component of amyloid deposits. Aβ1–40 wild-type–AChE fibrillar complexes, similar to neuronal cells, resulted in an increased toxicity on vascular cells. Previous reports showing that antioxidants are able to reduce the toxicity of Aβ fibrils on neuronal cells prompted us to test the effect of vitamin E, vitamin C, and 17β-estradiol on vascular damage induced by Aβwild-type and AβGlu22→Gln. Our data indicate that vitamin E attenuated significantly the Aβ-mediated cytotoxicity on vascular cells, although 17β-estradiol and vitamin C failed to inhibit the cytotoxicity induced by Aβ fibrils.

Plasma homocysteine and vitamin B12 serum levels, red blood cell folate concentrations, C677T methylenetetrahydrofolate reductase gene mutation and risk of recurrent miscarriage: a case-control study in Spain.

Background: Hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) gene mutation have been postulated as a possible cause of recurrent miscarriage (RM). There is a wide variation in the prevalence of MTHFR polymorphisms and homocysteine (Hcy) plasma levels among populations around the world. The present study was undertaken to investigate the possible association between hyperhomocysteinemia and its causative genetic or acquired factors and RM in Catalonia, a Mediterranean region in Spain. Methods: Sixty consecutive patients with ≥ 3 unexplained RM and 30 healthy control women having at least one child but no previous miscarriage were included. Plasma Hcy levels, MTHFR gene mutation, red blood cell (RBC) folate and vitamin B12 serum levels were measured in all subjects. Results: No significant differences were observed neither in plasma Hcy levels, RBC folate and vitamin B12 serum levels nor in the prevalence of homozygous and heterozygous MTHFR gene mutation between the two groups studied. Conclusions: In the present study RM is not associated with hyperhomocysteinemia, and/or the MTHFR gene mutation.

Patterns of variability of retinol levels in a harbour porpoise population from an unpolluted environment

Organochlorine compounds (OC) are known to induce vitamin A (retinoids) deficiency in mammals, which may be associated with impairment of immunocompetence, reproduction and growth. This makes retinoids a potentially useful biomarker of organochlorine impact on marine mammals. However, use of retinoids as a biomarker requires knowledge about its intrapopulation patterns of variation in natural conditions, information which is not currently available. We investigated these patterns in a cetacean population living in an unpolluted environment. 100 harbour porpoises Phocoena phocoena from West Greenland were sampled during the 1995 hunting season. Sex, age, morphometrics, nutritive condition, and retinol (following saponification) and OC levels in blubber were determined for each individual. OC levels found were extremely low and therefore considered unlikely to affect the population adversely: mean blubber concentrations, expressed on an extractable basis, were 2.04 (SD = 1.1) ppm for PCBs and 2.76 (SD = 1.66) ppm for tDDT. The mean blubber retinol concentration for the overall population was 59.66 (SD = 45.26) mu g g(-1). Taking into account the high contribution of blubber to body mass, blubber constitutes a significant body site for retinoid deposition in harbour porpoises. Retinol concentrations did not differ significantly between geographical regions or sexes, but they did correlate significantly (p <0.001) with age. Body condition, measured by determining the lipid content of the blubber, did not have a significant effect on retinol levels but the individuals examined were considered to be in an overall good nutritive condition. It is concluded that measurement of retinol concentrations in blubber samples is feasible and has a potential for use as a biomarker of organochlorine exposure in cetaceans. However, in order to do so, biological information, particularly age, is critical for the correct assessment of physiological impact

Genetically-defined deficiency of mannose-binding lectin is associated with protection after experimental stroke in mice and outcome in human stroke

The complement system is a major effector of innate immunity that has been involved in stroke brain damage. Complement activation occurs through the classical, alternative and lectin pathways. The latter is initiated by mannose-binding lectin (MBL) and MBL-associated serine proteases (MASPs). Here we investigated whether the lectin pathway contributes to stroke outcome in mice and humans.