TwinsMX: Exploring the Genetic and Environmental Influences on Health Traits in the Mexican Population.

TwinsMX registry is a national research initiative in Mexico that aims to understand the complex interplay between genetics and environment in shaping physical and mental health traits among the country's population. With a multidisciplinary approach, TwinsMX aims to advance our knowledge of the genetic and environmental mechanisms underlying ethnic variations in complex traits and diseases, including behavioral, psychometric, anthropometric, metabolic, cardiovascular and mental disorders. With information gathered from over 2800 twins, this article updates the prevalence of several complex traits; and describes the advances and novel ideas we have implemented such as magnetic resonance imaging. The future expansion of the TwinsMX registry will enhance our comprehension of the intricate interplay between genetics and environment in shaping health and disease in the Mexican population. Overall, this report describes the progress in the building of a solid database that will allow the study of complex traits in the Mexican population, valuable not only for our consortium, but also for the worldwide scientific community, by providing new insights of understudied genetically admixed populations.

Characterizing T-cell receptor gamma-variable gene in Aotus nancymaae owl monkey peripheral blood.

Gammadelta T lymphocytes have a heterodimeric complex formed by the association of gamma and delta chains as receptor. Proliferation of this lymphocyte population has been observed, when infection by several pathogens such as Mycobacterium tuberculosis and Plasmodium spp. occurs. The New World Monkey Aotus nancymaae has become a very good experimental model for the immunological and physiopathological study of these infectious agents. The A. nancymaae gamma-variable region was characterized from peripheral blood samples by using cDNA and genomic DNA polymerase chain reaction amplification, DNA sequencing, and dot-blot hybridization techniques. Seventeen different T-cell receptor gamma-variable (TCRGV) sequences were obtained. These sequences were distributed among TCRGV subsets 1, 2, or 3, according to human subset classification. Although no subset 4 amplification was obtained, this subset was detected by dot-blot hybridization. The presence of these 4 subsets resembles the behavior displayed by 'gammadelta-low species' (humans and mice), where high diversity among these lymphocytes can be observed. Homologies greater than 70% were found with respect to humans. Sequence convergence between human and A. nancymaae subsets 1 and 3 highlights Aotus as a promising model for studying these lymphocyte functions.

Mutations in mitochondrial aldehyde dehydrogenase (ALDH2) change cofactor affinity and segregate with voluntary alcohol consumption in rats.

Genetic factors influence alcohol consumption and alcoholism. A number of groups have bred alcohol drinker and non drinker rat strains, but genetic determinants remain unknown. The University of Chile rat lines UChA (low drinkers) and UChB (high drinkers) display differences in the relative K(m) for NAD+ of mitochondrial aldehyde dehydrogenase (ALDH2) but no V(max) differences. The relative K(m) differences may be due to mitochondrial changes or to genetic differences coding for ALDH2. We investigated whether there are differences in the coding regions of ALDH2 cDNA in these lines and whether the Aldh2 genotype predicts the phenotype of alcohol consumption and the K(m) of ALDH2 for NAD+. Liver cDNA was prepared, and the Aldh2 transcript was amplified, cloned and sequenced. Genotyping was conducted by DNA amplification and restriction enzyme digestion. When compared to Aldh21 of Sprague-Dawley, 94% of the UChA (low drinker) rats (n = 61), presented a mutation that changes Gln67 to Arg in the mature enzyme (allele referred to as Aldh22). In UChB (high drinker) rats (n = 69), 58% presented the Aldh21 allele, while 42% presented the Gln67Arg change plus a second mutation that changed Glu479 to Lys (allele Aldh23). The Aldh22 allele was absent in high drinker rats. Rats of different Aldh2 genotypes displayed marked phenotypic differences in both ethanol consumption (g/kg/day; means +/- SE): (Aldh21/Aldh21) = 5.7 +/- 0.2, (Aldh22/Aldh22) = 0.9 +/- 0.2 and (Aldh23/Aldh23) = 4.6 +/- 0.2; and K(m)s for NAD+ of 43 +/- 3 microm, 132 +/- 13 microm and 41 +/- 2 microm, respectively (Aldh22 versus Aldh21 or Aldh23; P < 0.0001 for both phenotypes). Overall, the data show that alleles of Aldh2 strongly segregate with the phenotype of ethanol consumption and the relative K(m) for NAD+ of ALDH2. Bases mutated suggest that non drinker Aldh22 is ancestral with regard to the coding changes in either Aldh21 or Aldh23, variants which would allow ethanol consumption and may provide an evolutionary advantage by promoting calorie intake from fermented products along with carbohydrates.

[Carbohydrate deficient transferrin, gammaglutamyl transferase and mean corpuscular volume in the evaluation of recent alcohol intake in excessive drinkers]. / Transferrina carbohidrato-deficiente, gammaglutamil transferasa y volumen corpuscular medio en la evaluación de la ingesta alcohólica reciente de bebedores excesivos.

BACKGROUND: There are no reliable markers to detect heavy drinking or as a tool to control abstinence compliance in alcoholic treatments. The Mean Corpuscular Volume (MCV), and the gammaglutamyl transpeptidase (GGT), are widely used although their predictive value is somewhat limited due to their low specificity. On the other hand, the Carbohydrate-deficient transferrin (CDT) described in the eighties is highly specific and would be of value in early detection of problem drinking. AIM: To compare the sensitivity and specificity of CDT, GGT, and MCV in order to evaluate their single and combined use as markers for detection of heavy drinking behaviour. PATIENTS AND METHODS: CDT, GGT, and MCV values were determined in blood samples from (a) alcoholics (drinking more than 100 9 alcohol/day; n = 47) and (b) healthy volunteers, teetotalers from the Church of Saints of Later Days (n = 34). At the time of sampling alcoholics were presently drinking or had been abstinent for no more than six weeks. ROC curves were used to determine the best cut-off point for each marker. RESULTS: Sensitivity was found to be similar for all three markers. Specificity was found higher for GGT (90.9%) and CDT (91.0%). The combined use of MCV, GGT and CDT, that is, when at least one of the markers is altered, was shown to detect 83% of the patients. No correlation was observed between the markers and the level of alcohol intake. CONCLUSIONS: CDT could be of value as a marker to detect heavy drinking when used with GGT and MCV values combined. CDT is particularly higher in drinking alcoholics and remains significantly high for at least six weeks after they stop drinking.

Protein binding of alpha-hydroxyethyl free radicals.

BACKGROUND: The auto-oxidation of ethanol is likely to proceed via the initial formation of hydroxyethyl radicals (HERs), the one-electron oxidation product. In the laboratory, HERs can be generated by the Fenton reaction (H2O2+ Fe+2) in the presence of ethanol. We report studies on the binding of HERs to serum albumin, generated under Fenton and non-Fenton conditions. METHODS: The generation of HER was determined by electron paramagnetic resonance spectroscopy. The formation of ethanol-derived protein adducts was determined by 14C-ethanol incorporation into serum albumin and by the binding of antibodies raised against HER adducts. RESULTS: We report that serum albumin, used as a model protein, is an effective trapping agent of HERs. In addition, HER radicals covalently bind to albumin to form acid stable adducts. Unexpectedly, we found that under aerobic conditions, the incubation of 50 mM ethanol and phosphate buffer (which contains iron traces) in the absence of the Fenton reagent yields HER radicals as shown by electron paramagnetic resonance spectroscopy and the formation of acid stable protein adducts that are recognized by antibodies raised against HER radical adducts. CONCLUSIONS: Proteins (serum albumin used as a model) are avid trapping agents of HER. There are minimal requirements for the generation of HER, because in the presence of oxygen and a phosphate buffer that contains traces of iron, ethanol readily generates HERs. Thus, HER production is likely to occur in many tissues. The ability of proteins to bind this ethanol radical should be valuable in the diagnosis of alcohol abuse and may be relevant to some of the chronic effects of ethanol.

Generation of acetate and production of ethyl-lysine in the reaction of acetaldehyde plus serum albumin.

We report that incubation of acetaldehyde with bovine serum albumin results in the generation of acetate in a reaction that is directly proportional to the levels of albumin and exponentially dependent on the concentration of acetaldehyde. Both reactants need to be present for acetate to be formed. The oxidation of acetaldehyde into acetate requires that a reduced product also be generated in the reaction. It was hypothesized that, at high concentrations, acetaldehyde itself may reduce the Schiff bases formed in the reaction of a second molecule of acetaldehyde with amino groups in the protein, resulting in the generation of ethyl-lysine moieties. Incubation of acetaldehyde (240 mM) with bovine serum albumin was found to generate ethyl-lysine moieties as determined by a specific monoclonal antibody. Immunization of rabbits with products of the reaction of bovine serum albumin with acetaldehyde led to the generation of antibodies that reacted to reduced adducts formed in the reaction of acetaldehyde and proteins in the presence of sodium cyanoborohydride. However, the generation of acetate from acetaldehyde plus albumin was 60-fold greater than could be explained by the reduction of Schiff bases, as determined by the maximal incorporation of [14C]-acetaldehyde into an acid-precipitable protein fraction. Thus, other mechanisms to generate acetate also occur. The present findings provide an explanation for earlier reports that acetaldehyde adducts formed under "nonreducing" conditions generate antibodies that recognize reduced acetaldehyde protein adducts. However, the mechanism by which the bulk of acetate is generated in the reaction of acetaldehyde and bovine serum albumin remains to be elucidated.

Anemia de fanconi: presentación de un caso / Fanconi's anemia: presentation of a case

La anemia de Fanconi es un desorden cromosómico caracterizado por una anemia aplástica familiar de carácter autosómico recesivo, que se manifiesta clínicamente con lesiones de piel, anormalidades congénitas de tipo esquelético, genitourinario y neuroocular, de baja prevalencia mundial. Se presenta un caso de anemia de Fanconi diagnósticado en un preescolar masculino de 33 meses de edad, hospitalizado en el Servicio de Pediatría del Hospital General "Patrocinio Peñuela Ruíz" de San Cristóbal. Se analizan los hallazgos clínicos y aspectos diagnósticos y terapéuticos de esta enfermedad

Efecto sobre S mutans y C albicans en acrílicos tratados con gluconato de clorhexidina al 0.5: in vitro / An in vitro correlation study between action time and inhibition area of S. mutans and C. albicans growing by means of acrylic treated with 0.5 percent clohexidine gluconate

Se trataron discos de acrílico mediante la inmersión en clorhexidina al 0,5 por ciento y se correlacionó el tiempo de exposición a un buffer con el área de inhibición de S. mutans y C. albicans. 102 discos se trataron mediante inmersión en clorhexidina al 0,5 por ciento durante 16 minutos. Del total de discos, 51 fueron destinados para la realización del antibiograma por difusión en un medio sembrado con S. mutans y 51 en uno sembrado con C.albicans. Para la realización del antibiograma, tres discos se llevaron a cultivo, sin sumergir en el buffer, constituyendo el tiempo cero, los restantes fueron sumergidos en solución buffer y retirados en grupos de tres, a intervalos de treinta minutos, hasta completar un total de 17 períodos de observación (8 horas). En otro grupo de 16 discos tratados, se realizó el antibiograma por difusión en un medio sembrado con S. mutans. Para su realización se introdujo al cultivo, un disco sin sumergir en el buffer, el que constituyó el tiempo cero. Los restantes fueron retirados a intervalos de dos minutos, hasta completar un período de observación de treinta minutos. Durante los primeros treinta minutos, se pudo observar que el tratamiento realizado a los discos, permitió la inhibición in Vitro del desarrollo de S. mutans y C. albicans, con una correlación de 85,4 porciento entre disminución de área de inhibición y tiempo de exposición a la solución buffer. Sin embargo, después de los 30 minutos iniciales, la inhibición in vitro fue independiente de la exposición al buffer. A partir de ese momento, se logra un efecto inhibitorio del desarrollo de S. mutans, pero no de C. albicans

Cytochrome P4502E1 hydroxyethyl radical adducts as the major antigen in autoantibody formation among alcoholics.

BACKGROUND & AIMS: We have previously reported that alcoholics have increased titers of immunoglobulins reacting with protein adducts of hydroxyethyl free radicals. Because hydroxyethyl radicals are produced during ethanol metabolism by liver microsomes, the aim of this study was to determine whether such antibodies recognize microsomal proteins complexed with hydroxyethyl radicals. METHODS: Liver microsomal proteins reacting with the anti-hydroxyethyl radical antibodies were characterized by an enzyme-linked immunosorbent assay and Western blotting. RESULTS: Alcoholic cirrhotics, but not patients with nonalcoholic cirrhosis or healthy subjects, had increased serum levels of immunoglobulin G and A directed against antigens produced in microsomes incubated with reduced nicotinamide adenine dinucleotide phosphate (NADPH) and ethanol. Such immunoreactivity was completely blocked when microsomes were incubated with ethanol in the presence of the spin-trapping agent 4-pyridyl-1-oxide-t-butyl nitrone or by preincubating the sera with hydroxyethyl radical-bound human albumin. Immunoblotting of proteins from human liver microsomes incubated with NADPH and ethanol showed that 86% of the sera from alcoholic cirrhotics reacted with a 52-kilodalton protein, whereas variable reactivity was observed with proteins of 78, 60, and 40 kilodaltons, respectively, The 52-kilodalton protein was identified by immunoblotting and immunoprecipitation as ethanol-inducible cytochrome P4502E1. CONCLUSIONS: Antibodies from alcoholic cirrhotics specifically recognized hydroxyethyl radical-cytochrome P4502E1 adducts, suggesting the possible implication of these antigens in the development of autoimmune reactions in alcoholic liver disease.

Esmalte aprismático en dientes permanentes: descripción al MEB / Prismless enamel in permanent teeths: SEM description

Existe poca información respecto al esmalte aprismático, para hacer una descripción de micromorfología, se utilizaron premolares y molares sanos los que fueron observados con MEB a diferentes aumentos. Se encontró este tipo de esmalte aprismático en fosas, fisuras y en la zona cervical. Se comentan lagunas consideraciones clínicas del grabado ácido del esmalte aprismático o su eliminación previo a restauración de odontología adhesiva

Ethanol-derived immunoreactive species formed by free radical mechanisms.

Recent studies have shown that the alpha-hydroxyethyl radical (CH3CHOH), a metabolite of ethanol, is produced in vitro and in vivo. We report studies that establish the immunogenicity of alpha-hydroxyethyl radical-derived protein adducts. Rat liver microsomes incubated in the presence of [14C]ethanol and NADPH (under aerobic conditions) incorporate 14C into acid-stable adducts. Incorporation was markedly inhibited by the free-radical scavenger alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone. Rabbits immunized with rat liver microsomes that had been preincubated with ethanol and NADPH generated antibodies that recognized polylysine-acetaldehyde adducts and adducts formed by incubation of proteins with an alpha-hydroxyethyl radical-generating system (ethanol plus H2O2 plus Fe2+). Rabbits immunized with microsomes that had been preincubated with ethanol and NADPH plus alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone generated antibodies that recognized polylysine-acetaldehyde adducts. However, their reactivity against alpha-hydroxyethyl-derived protein epitopes was greatly reduced or was virtually abolished. Data indicate that microsomes metabolizing ethanol generate two types of adducts, acetaldehyde-derived adducts and alpha-hydroxyethyl radical-derived adducts, both of which are immunogenic. Immunization of rabbits with alpha-hydroxyethyl-bovine serum albumin adducts led to the production of antibodies that recognized alpha-hydroxyethyl-rabbit serum albumin adducts but did not recognize the native protein. Chronic alcohol feeding of rats led to the production of antibodies that recognized alpha-hydroxyethyl-rat serum albumin adducts but did not recognize rat serum albumin. The study (i) indicates that alpha-hydroxyethyl radical-derived protein adducts are immunogenic, (ii) supports earlier work that proposed that alpha-hydroxyethyl radicals generated in different systems bind covalently to proteins, and (iii) demonstrates the formation of antibodies to alpha-hydroxyethyl-derived protein adducts after chronic alcohol ingestion in vivo. The findings may have implications in the identification of chronic alcohol abuse and the pathogenesis of alcohol-induced organ damage.

The pyrimidine derivative BW 1003C87 protects against excitotoxic lesions induced by kainate in the rat striatum.

We have investigated the neuroprotective effect of the pyrimidine derivative BW 1003C87 (5-[2,3,5-trichlorophenyl] pyrimidine-2,4-diamine ethane sulphonate) against striatal and hippocampal lesions induced by kainic acid (KA), N-methyl-D-aspartate (NMDA) and (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ((S)-AMPA) in the rat. BW 1003C87 20 mg/kg i.p. administered pre- and post-treatment (20 min prior to excitotoxic injection and again 4 h later) protects against the lesions induced by KA (1.1 nmol) in the hippocampus (CA2 pyramidal cells only; 40% protection, P < 0.05). In the striatum, the same dose of BW 1003C87 significantly reduces KA toxicity (80% protection, P < 0.001). BW 1003C87 has no significant effect on the lesions induced by NMDA (30 nmol) or S-AMPA (6 nmol) in either brain region. These results are consistent with previous studies showing that the neurotoxicity of KA occurs via an indirect mechanism involving glutamate release.

Efectos del termociclado y las cargas cíclicas sobre dos adhesivos dentinarios SB-2 y SBMP: estudio in vitro / Effects of termocycling and cyclic loads over 2 dentin adhesives: SB-2 and SBMP: in vitro study

In vitro study was carry out in order to compare the microleakage of two different dentin adhesives SB-2 and SBMP in class V. One hundred class V cavities were designed in the enamel-dentin joint. After restorations they were thermocycled, loaded, stained and sectionated before the microlekage were observed. All the groups showed microleakege. The enamel walls presented better beahvior than roots walls. In roots areas were found significative higher microleakage than enamel walls. Enamel walls of Silux Plus, showed les leakage with SB2, white Z 100 worked better in roots walls with SBMP. Enamel areas of ceramic inlays were less leakage with SB2, and composites restoration always showed better sealed than ceramic inlays with both, SB2 and SBMP

Effect of the non-NMDA receptor antagonist GYKI 52466 on the microdialysate and tissue concentrations of amino acids following transient forebrain ischaemia.

The effect of the non-N-methyl-D-aspartate (non-NMDA) receptor antagonist 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride (GYKI 52466) on ischaemia-induced changes in the microdialysate and tissue concentrations of glutamate, aspartate, and gamma-aminobutyric acid (GABA) was studied in rats. Twenty minutes of four-vessel occlusion resulted in a transient increase in microdialysate levels of glutamate, aspartate, and GABA in striatum, cortex, and hippocampus. Administration of GYKI 52466 (10 mg/kg bolus + 10 mg/kg/60 min intravenously starting 20 min before onset of ischaemia) inhibited ischaemia-induced increases in microdialysate glutamate and GABA in striatum without affecting the increases in hippocampus or cortex. Twenty minutes of four-vessel occlusion resulted in immediate small decreases and larger delayed (72 h) decreases in tissue levels of glutamate and aspartate. Transient increases in tissue levels of GABA were shown in all three structures at the end of the ischaemic period. At 72 h, after the ischaemic period, significantly reduced GABA levels were observed in striatum and hippocampus. GYKI 52466, given under identical conditions as above, augmented the ischaemia-induced decrease in striatal tissue levels of glutamate and aspartate, without significantly affecting the decreases in hippocampus and cortex. Twenty minutes of ischaemia resulted in a large increase in microdialysate dopamine in striatum. GYKI 52466 failed to inhibit this increase. Kainic acid (500 microM infused through the probe for 20 min) caused increases in microdialysate glutamate and aspartate in the striatum. GYKI 52466 (10 mg/kg bolus + 10 mg/kg/60 min) completely inhibited the kainic acid-induced glutamate release. In conclusion, the action of the non-NMDA antagonist, GYKI 52466, in the striatum is different from that in the cortex and hippocampus. The inhibition by GYKI 52466 of ischaemia-induced and kainate-induced increases in microdialysate glutamate concentration in the striatum may be related to the neuroprotection provided by GYKI 52466 in this region.

Simple method for the preparation of antigen emulsions for immunization.

We have developed a rapid, safe, and reliable method to prepare emulsions of water-soluble antigens in an adjuvant oil phase for immunization purposes. The method, based on well established emulsification principles, employs a three-way 'T' connector to which three disposable syringes are attached. The system allows the stepwise addition of small volumes of the water phase, into the oil phase. We have compared the time required for emulsification, the rate of antigen release from the emulsion into a physiological phase, and the immunogenic properties of bovine serum albumin and transferrin contained in emulsions made by the new stepwise addition method, with those made by the widely used double-hubbed needle method. We report a significantly shorter (P < 0.001) and a more reproducible emulsification time for the stepwise addition method (6.1 +/- 2.1 min; mean +/- SD) than for the double-hubbed needle method (41.1 +/- 28.0 min). The stepwise addition method always yielded water-in-oil emulsions, while the double-hubbed needle method failed, about 20% of the time, to produce a water-in-oil emulsion after 120 min of mixing. Since the stepwise addition method employs a connector with a larger inner diameter (1.75 mm) than the one required for the double-hubbed needle method (0.84 mm); the pressure required for the former is markedly reduced compared with that required for the latter, thus making the new method safer and less labor-intensive. The rate of antigen release from the emulsions was significantly slower when the stepwise addition method was employed (P < 0.01). There were no differences in viscosity and stability in the emulsions prepared by the two methods. The ability of antigen-containing emulsions to elicit an immune response was found to be identical by the two methods; no significant differences were found in antibody titers as determined by enzyme-linked immunosorbent assays. These characteristics make the stepwise addition system the method of choice.

Effect of NO synthase inhibition on NMDA- and ischaemia-induced hippocampal lesions.

We assessed the effect of NG-Nitro-L-arginine methylester (L-NAME), an inhibitor of nitric oxide synthase, on the hippocampal lesions induced either by the focal injection of N-methyl-D-aspartate (NMDA) or (s)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (s-AMPA) or by 10 min of severe forebrain ischaemia (4-vessel occlusion), in the rat. We find that L-NAME, 20 or 40 mg kg-1, selectively decreases NMDA-induced CA1 lesions while it has no effect on AMPA toxicity. L-NAME, 20 mg kg-1, does not decrease hippocampal damage induced by ischaemia. These results suggest that NO contributes to NMDA toxicity and support data indicating that NMDA receptor antagonists fail to protect against hippocampal CA1 lesions in the 4-vessel occlusion model.

Determinación del sellado marginal en incrustaciones cerámicas MOD / Marginal seal determination in MOD ceramic inlays

Se determina mediante MEB el comportamiento de la resina compuesta de cementación, in vitro en restauraciones cerámicas grabadas. Los resultados indican que las microporosidades fueron penetradas por las resinas de cementación. Se obtuvo un espesor promedio de la línea de ementación de 93,7 µm, presentándose mayor desajuste en las zonas marginales. En las 12 piezas estudiadas la resina de cementación mostró un contorno armónico respecto de la restauración cerámica y la pieza dentaria

GYKI 52466 blocks the increase in extracellular glutamate induced by ischaemia.

In vivo microdialysis has been used to study the effect of pre- or post-ischaemic administration of the non-NMDA antagonist 1-(4-amino-phenyl)-4-methyl-7, 8-methyl-endioxyl-5H-2,3- benzodiazepine hydrochloride (GYKI 52466), on the increases in extracellular glutamate levels induced by 20 minutes of four vessel occlusion in rats. In control rats, ischaemia resulted in transient increases in glutamate (4 fold), aspartate (6 fold) and gamma-aminobutyric acid (GABA) (15 fold) and decreases in glutamine (0.5 fold). Intravenous administration of GYKI 52466 (10 mg kg-1 bolus followed by 10 mg kg-1 h-1 infusion) beginning 20 minutes prior to the induction of ischaemia abolished ischaemia-induced glutamate release without affecting the increases in aspartate and GABA and the decrease in glutamine. Administration of GYKI 52466 immediately post-ischaemia resulted in a more rapid return of glutamate levels to basal values.