Identification of amacrine neurons with a glycinergic and GABAergic phenotype in the mouse retina.

The amacrine neurons in the mammalian retina comprise a large variety of cell types with distinct properties and functions that serve to integrate and modulate signals presented to output neurons. The majority of them use either glycine or GABA as inhibitory neurotransmitters and express the glycine transporter 1 (GlyT1) or glutamic acid decarboxylase (GAD67) and GABA transporters (GAT1 and GAT3), as a glycinergic or GABAergic marker respectively. We report here a novel subpopulation of amacrine neurons expressing both, GABAergic and glycinergic markers, in retinas from wild-type C57BL/6J mice and two transgenic lines. In retinal sections from the transgenic line expressing eGFP under the control of the glycine transporter 2, eGFP expression was exclusively found in cell bodies and dendrites of inhibitory amacrine neurons, identified for their immunoreactivity to syntaxin 1A. All of the glycinergic and a large portion of the GABAergic amacrine neurons contained eGFP; of these, 8-10% of GlyT1 positive neurons were also labeled either with GAD67, GAT1 or GAT3. These findings were confirmed in retinas from a wild-type and a mouse line expressing eGFP under the GAD67 promoter and two different anti-GlyT1 antibodies, showing the presence of a subpopulation with a dual phenotype. Moreover, eGFP-positive dendrites on both mouse lines were found juxtaposed to GlyR subunits and the scaffold protein gephyrin in several areas of the inner plexiform layer, demonstrating the glycinergic character of these neurons. This dual phenotype was also demonstrated in primary retina cultures, in which isolated neurons were positive for GlyT1 and GAD67 or GAT1/3. Altogether, these data provide compelling evidence of a subpopulation of dual inhibitory, glycinergic/GABAergic amacrine neurons. The co-release of both neurotransmitters may serve to strengthen the inhibition on ganglion cells under synaptic hyperexcitability.

Protein-conformational diseases in childhood: Naturally-occurring hIAPP amyloid-oligomers and early ß-cell damage in obesity and diabetes.

BACKGROUND AND AIMS: This is the first time that obesity and diabetes mellitus (DM) as protein conformational diseases (PCD) are reported in children and they are typically diagnosed too late, when ß-cell damage is evident. Here we wanted to investigate the level of naturally-ocurring or real (not synthetic) oligomeric aggregates of the human islet amyloid polypeptide (hIAPP) that we called RIAO in sera of pediatric patients with obesity and diabetes. We aimed to reduce the gap between basic biomedical research, clinical practice-health decision making and to explore whether RIAO work as a potential biomarker of early ß-cell damage. MATERIALS AND METHODS: We performed a multicentric collaborative, cross-sectional, analytical, ambispective and blinded study; the RIAO from pretreated samples (PTS) of sera of 146 pediatric patients with obesity or DM and 16 healthy children, were isolated, measured by sound indirect ELISA with novel anti-hIAPP cytotoxic oligomers polyclonal antibody (MEX1). We carried out morphological and functional studied and cluster-clinical data driven analysis. RESULTS: We demonstrated by western blot, Transmission Electron Microscopy and cell viability experiments that RIAO circulate in the blood and can be measured by ELISA; are elevated in serum of childhood obesity and diabetes; are neurotoxics and works as biomarkers of early ß-cell failure. We explored the range of evidence-based medicine clusters that included the RIAO level, which allowed us to classify and stratify the obesity patients with high cardiometabolic risk. CONCLUSIONS: RIAO level increases as the number of complications rises; RIAOs > 3.35 µg/ml is a predictor of changes in the current indicators of ß-cell damage. We proposed a novel physio-pathological pathway and shows that PCD affect not only elderly patients but also children. Here we reduced the gap between basic biomedical research, clinical practice and health decision making.

Genotyping Toxoplasma gondii with the B1 Gene in Naturally Infected Sheep from an Endemic Region in the Pacific Coast of Mexico.

Toxoplasma gondii is a protozoan parasite with a broad ecological valence, which has been detected in a wide range of hosts and landscapes. Although the genus is considered monospecific, in recent years it has been demonstrated to exhibit more genetic variability than previously known. In Mexico, there are few genotyping studies, which suggest that classical, autochthonous, and atypical strains are circulating. The goal of this study was to describe T. gondii genetic diversity in naturally infected sheep from Colima, Mexico. This is a good site to study ecological aspects of this parasite since it is located between the Nearctic and Neotropical ecozones and it includes domestic and wild risks for transmission. We analyzed 305 tissue samples of semicaptive sheep from six coastal and central zones of Colima and border zones of Michoacán. We used an 803 bp amplicon of the B1 gene to genotype T. gondii and seroprevalence was determined by ELISA. Indexes for genetic diversity and genetic differentiation were calculated and compared with reference strains from North America (NA) and South America (SA). Twenty-three tissue samples were positive for the B1 gene by PCR, which were sequenced. Crude prevalence was 24.4%. The genetic analysis showed 16 variable sites along the 803 bp region that grouped all sequences into 13 haplotypes in the phylogenetic tree. Bayesian and haplotype network analysis showed nine new B1-types, of which three were frequent and six had unique alleles. Comparisons among sequence sets revealed that the Mexican population had lower differentiation than SA and an intermediate genetic variability between South America and North America. The B1 gene analysis showed new T. gondii haplotypes in naturally infected sheep; therefore, this marker could be initially used in molecular screening studies to identify potentially virulent genotypes of this parasite using natural host samples directly.

Nanomechanical properties of human skin and introduction of a novel hair indenter.

The mechanical resistance of the stratum corneum, the outermost layer of skin, to deformation has been evaluated at different length scales using Atomic Force Microscopy. Nanomechanical surface mapping was first conducted using a sharp silicon tip and revealed that Young׳s modulus of the stratum corneum varied over the surface with a mean value of about 0.4GPa. Force indentation measurements showed permanent deformation of the skin surface only at high applied loads (above 4µN). The latter effect was further demonstrated using nanomechanical imaging in which the obtained depth profiles clearly illustrate the effects of increased normal force on the elastic/plastic surface deformation. Force measurements utilizing the single hair fiber probe supported the nanoindentation results of the stratum corneum being highly elastic at the nanoscale, but revealed that the lateral scale of the deformation determines the effective elastic modulus.This result resolves the fact that the reported values in the literature vary greatly and will help to understand the biophysics of the interaction of razor cut hairs that curl back during growth and interact with the skin.

First isolation of Toxoplasma gondii from cats of Colima, Mexico: tissue distribution and genetic characterization.

Toxoplasma gondii is among the commonest zoonotic infectious agents worldwide. It infects many warm-blooded animals, including felines, the definitive hosts. This parasite is now classified in 15 haplogroups spread out around the world. Few reports reveal a predominance of genotypes I and III in Mexico, although recombinant and atypical variants have also been found in humans and animals. The aim of this study was to detect, isolate and genotype T. gondii from cats of Colima Mexico, and to analyze tissue distribution of the parasite. IgG specific antibodies were investigated in 48 serum samples from unwanted and stray cats by indirect ELISA. Isolation in mice and molecular characterization by PCR-RFLP and sequencing were attempted using pools of brain, heart, liver, lung, spleen and brachiocephalic muscle samples of seropositive cats. Fourteen animals (29.2%) were seropositive, the frequency ranged between 27.3 and 40% among the different localities. Ten seropositive animals were euthanized, eight of them were positive for the B1 gene by conventional PCR. More frequently infected tissues were the brachiocephalic muscle (75.0%) the brain (63.0%) and the spleen (63.0%). Genotype III was determined for the SAG3 locus of the parasite infecting an unwanted cat. Tachyzoites were isolated from the peritoneal cavity of two mice inoculated with the tissue pool of one kitten. Type I alleles were found in SAG1, SAG2, SAG3, BTUB, GRA6, c29-2 and PK1 loci, while c22-8 was type II, and L358 and Apico were type III. This genotype corresponds to ToxoDB genotype #28. This is the first T. gondii isolate genetically characterized in Colima, Mexico and is different to other isolations of the country.

Words translated in sentence contexts produce repetition priming in visual word comprehension and spoken word production.

Previous research with words read in context at encoding showed little if any long-term repetition priming. In Experiment 1, 96 Spanish-English bilinguals translated words in isolation or in sentence contexts at encoding. At test, they translated words or named pictures corresponding to words produced at encoding and control words not previously presented. Repetition priming was reliable in all conditions, but priming effects were generally smaller for contextualized than for isolated words. Repetition priming in picture naming indicated priming from production in context. A componential analysis indicated priming from comprehension in context, but only in the less fluent language. Experiment 2 was a replication of Experiment 1 with auditory presentation of the words and sentences to be translated. Repetition priming was reliable in all conditions, but priming effects were again smaller for contextualized than for isolated words. Priming in picture naming indicated priming from production in context, but the componential analysis indicated no detectable priming for auditory comprehension. The results of the two experiments taken together suggest that repetition priming reflects the long-term learning that occurs with comprehension and production exposures to words in the context of natural language.

Low-grade systemic inflammation and leptin levels were improved by arm cranking exercise in adults with chronic spinal cord injury.

OBJECTIVE: To ascertain the effect of arm cranking exercise on improving plasma levels of inflammatory cytokines and adipokines in untrained adults with chronic spinal cord injury (SCI). DESIGN: Longitudinal study. SETTING: Community-based supervised intervention. PARTICIPANTS: Men (N=17) with complete SCI at or below T5 volunteered for this study. Participants were randomly allocated to the intervention (n=9) or control group (n=8) using a concealed method. INTERVENTION: A 12-week arm cranking exercise program of 3 sessions per week consisted of warm-up (10-15min), arm crank (20-30min; increasing 2min and 30s every 3wk) at a moderate work intensity of 50% to 65% of heart rate reserve (starting at 50% and increasing 5% every 3wk), and cool-down (5-10min). MAIN OUTCOME MEASURES: Plasma levels of leptin, adiponectin, plasminogen activator inhibitor-1, tumor necrosis factor-alpha, and interleukin-6 were determined. Furthermore, physical fitness (maximum oxygen consumption [V˙O2max]) and body composition (anthropometric index, waist circumference, and body mass index) were also assessed. RESULTS: Plasma levels of leptin, tumor necrosis factor-alpha, and interleukin-6 were significantly decreased after the completion of the training program. Similarly, the anthropometric index and waist circumference were diminished too. A moderate correlation was found between leptin and the anthropometric index. Finally, V˙O2max was significantly increased, suggesting an improvement of physical fitness in the intervention group. No changes were found in the control group. CONCLUSIONS: Arm cranking exercise improved low-grade systemic inflammation by decreasing plasma levels of inflammatory cytokines. Furthermore, it also reduced plasma leptin levels. Long-term, well-conducted studies are still required to determine whether these changes may improve clinical outcomes of adults with chronic SCI.

A short-term training program reduced oxidative damage in elderly diabetic rats.

INTRODUCTION: Recent studies concluded long-term training programs have improved antioxidant system in young and adults diabetic rats. However, to our knowledge, little attention has been paid to elderly individuals. OBJECTIVE: To assess the influence of a shorter training program in reducing oxidative damage in elderly diabetic rats. MATERIAL AND METHODS: Twenty-four male homozygous Zucker diabetic fatty rats (Gmi, fa/fa) aged 18-weeks with an average weight of 370- 450 g were purchased. After a 2-week period of environmental adaptation, animals were randomly distributed into exercised group (n = 12) that performed a 6-week swimming training protocol and sedentary group (n = 12). Animals were sacrificed 24-h after the last exercise session under anesthesia. Serum metabolic profile was determined. Lipid oxidation, expressed as malondialdehyde and protein oxidation, expressed as carbonyl groups, were assessed in plasma samples. This protocol was approved by an Institutional Ethics Committee. RESULTS: Exercised rats improved significantly their metabolic profile in comparison to controls. Plasma malondialdehyde (1.58 ± 0.39 vs. 2.06 ± 0.41 nmol/mL; p = 0.016) and carbonyl group levels (1.37 ± 0.33 vs. 1.62 ± 0.58 UA; p = 0.011) were also significantly lowered in exercised rats when compared to sedentary counterparts. CONCLUSIONS: A 6-week swimming training program reduced lipid and protein oxidation in elderly fatty diabetic rats. Further studies on this topic are required.

Resistance circuit training reduced inflammatory cytokines in a cohort of male adults with Down syndrome.

BACKGROUND: It is widely accepted that muscle strength plays a key role on functional tasks of daily living and employability in individuals with Down syndrome (DS). Recent studies have also reported resistance training may improve chronic inflammation in other clinical situations. This is the first study conducted to determine the effect of resistance circuit training on low-grade systemic inflammation in adults with DS. MATERIAL/METHODS: A total of 40 young male adults with DS were recruited for the trial through different community support groups for people with intellectual disabilities and their families. They had medical approval for physical activity participation. Twenty-four were randomly assigned to perform resistance circuit training with 6 stations, 3 days per week for 12 weeks. Exercise intensity was based on function of the 8RM assessments. The control group included 16 age-, sex-, and BMI-matched adults with Down syndrome. Plasma levels of leptin, adiponectin, and TNF-a were assessed by commercial ELISA kits. C-reactive protein (CRP) was assessed by nephelometry. Body composition was also determined, measuring fat-free mass percentage and waist circumference (WC). This protocol was approved by our Institutional Ethics Committee. RESULTS: Plasma levels of leptin, TNF-a, and IL-6 were significantly decreased after the completion of the training program, as were fat-free mass and WC. No sports-related injuries or withdrawals from the program were reported during the entire study period. No changes were observed in the control group. CONCLUSIONS: Resistance circuit training improved low-grade systemic inflammation in male sedentary adults with DS.

Arm-cranking exercise reduced oxidative damage in adults with chronic spinal cord injury.

OBJECTIVE: To assess the effect of a 12-week arm-cranking exercise program on reducing oxidative damage in untrained adults with chronic spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Community-based supervised intervention. PARTICIPANTS: Male adults with complete SCI at or below the fifth thoracic level (T5) (N=17) volunteered for this study. Participants were randomly allocated to the intervention (n=9) or control (n=8) group using a concealed method. INTERVENTION: A 12-week arm-cranking exercise program, 3 sessions/wk, consisting of warming-up (10-15min) followed by a main part in arm-crank (20-30min [increasing 2min and 30s every 3wk]) at a moderate work intensity of 50% to 65% of the heart rate reserve (starting at 50% and increasing 5% every 3 weeks) and by a cooling-down period (5-10min). MAIN OUTCOME MEASURES: Plasmatic levels of total antioxidant status as well as erythrocyte glutathione peroxidase activity were measured. Lipid and protein oxidation were determined as malondialdehyde and carbonyl group levels, respectively. Furthermore, physical fitness and body composition were assessed. RESULTS: When compared with baseline results, maximum oxygen consumption was significantly increased (P=.031), suggesting an improvement in physical fitness in the intervention group. Regarding the antioxidant defense system, it was found that both total antioxidant status (P=.014) and erythrocyte glutathione peroxidase activity (P=.027) were significantly increased at the end of the training program. As a consequence, plasmatic levels of malondialdehyde (P=.008) and carbonyl groups (P=.022) were significantly reduced. CONCLUSION: A 12-week arm-cranking exercise program improved the antioxidant defense system in adults with chronic SCI, which may finally attenuate both lipid and protein oxidation in this population.

Mejoras del porcentaje y distribución abdominal de masa grasa en mujeres con discapacidad intelectual tras entrenamiento aeróbico de 10 semanas / A short training program reduced fat mass and abdominal distribution in obese women with intellectual disability

En la actualidad se acepta que la obesidad es un grave problema de salud pública. La situación es aún más preocupante entre las personas con discapacidad intelectual, especialmente entre las mujeres. Afortunadamente recientes estudios sugieren la utilidad del ejercicio como estrategia frente a la obesidad. Sin embargo, la mayoría de estos estudios utilizan grupos mixtos (hombres y mujeres) o varones, siendo escasa la información sobre un grupo homogéneo de mujeres. Por consiguiente nos planteamos como hipótesis que un programa de entrenamiento de 10 semanas podría reducir el porcentaje de masa grasa y la distribución abdominal en mujeres obesas con síndrome de Down. En nuestro estudio participaron 20 mujeres adultas (18-30 años) con un cociente intelectual de 50-69 según la escala Stanford-Binet y diagnóstico citogenético de trisomía 21. Todas presentaban obesidad definida como IMC>30 kg/m2. Once de las participantes se asignaron aleatoriamente al grupo experimental y desarrollaron un programa de entrenamiento de 10 semanas de tipo aeróbico con 3 sesiones/semana. El porcentaje de masa grasa se determinó mediante impedanciometría bioeléctrica (Tanita TBF521). Para obtener el índice cintura/cadera se midieron las circunferencias de la cintura y la cadera utilizando una cinta antropométrica. Nuestro protocolo fue aprobado por un Comité de Ética Institucional. Nuestros resultados confirman que el ejercicio aeróbico redujo significativamente el porcentaje de masa grasa, el índice cintura/cadera y el perímetro de la cintura (p<0,05). Por el contrario no se observaron cambios en el grupo control. Concluimos que un programa de entrenamiento de 10 semanas consiguió mejorar la composición corporal de mujeres obesas con síndrome de Down. Futuros estudios longitudinales bien conducidos y controlados son necesarios para conocer el impacto de esta mejora en el manejo clínico de este grupo.

Recent studies have reported obesity prevalence in people with intellectual disability is even higher than in the general population what may finally lead to impair their health status and increase healthcare costs. Fortunately several studies have reported regular exercise may improve body composition in obese people with and without intellectual disability. To the best of our knowledge this is the first study conducted exclusively in female participants with intellectual disability, in an attempt to keep our sample homogeneous. To date, many studies focused on the influence of regular exercise in people with intellectual disability have recruited mixed (males and females) groups in order to increase their sample size to strengthen research designs. Therefore, we assessed the influence of a 10-week aerobic training program on fat mass percentage and indices of obesity in women with Down syndrome. To get this goal, twenty obese young women with Down syndrome volunteered for this study. Eleven were randomly assigned to perform a 10-week aerobic training program, 3 sessions/week, consisting of warming-up followed by a main part in a treadmill (30-40 min) at a work intensity of 55-65% of peak heart rate and a cooling-down period. Control group included 9 age, sex and BMI matched women with Down syndrome. Fat mass percentage and fat distribution were measured. This protocol was approved by an Institutional Ethics Committee. When compared to baseline, fat mass percentage, waist circumference and waist to hip ratio were significantly reduced after training. Conversely, no changes were reported in controls. It was concluded a 10-week training program reduced fat mass in obese adult women with Down syndrome.

Anti-inflammatory effect of exercise, via reduced leptin levels, in obese women with Down syndrome.

Recent studies have reported that obese young people with Down syndrome suffer from low-grade systemic inflammation. Whereas this condition may be improved in the general population by regular exercise, the problem has received no attention in the case of people with intellectual disability. Therefore, the authors' aim was to assess the influence of aerobic training on plasma adipokines in obese women with Down syndrome. Twenty obese young women with Down syndrome volunteered for this study, 11 of whom were randomly assigned to a 10-wk aerobic-training program. They attended 3 sessions/wk, which consisted of warm-up exercises followed by the main activity on a treadmill (30-40 min) at a work intensity of 55-65% of peak heart rate and ended with a cooling-down period. The control group included 9 women with Down syndrome matched for age, sex, and body-mass index. Fat-mass percentage and distribution were measured, and plasma adipokine levels (leptin and adiponectin) were assessed. In addition, each participant performed a maximal graded continuous treadmill exercise test. These parameters were assessed pre- and postintervention. Aerobic training produced a significant increase in participants' maximal oxygen uptake (20.2 ± 5.8 vs.23.7 ± 6.3 ml · kg-1 · min-1; p < .001), and plasma leptin levels were significantly reduced in the intervention group (54.2 ± 6.7 vs.45.7 ± 6.1 ng/ml; p = .026). Further significant correlations between plasma leptin and indices of obesity were found. In contrast, no significant changes were found in adiponectin levels (p > .05). None of the tested parameters changed in the control group. In conclusion, a 10-week training program reduced leptin levels in obese young women with Down syndrome.

A 6-week training program increased muscle antioxidant system in elderly diabetic fatty rats.

BACKGROUND: It is widely accepted that oxidative stress is associated with the physiopathology of type 2 diabetes mellitus. In fact, it has been pointed out as a therapeutic target in T2DM. Fortunately, several papers have reported that long-term training programs improved the antioxidant system in young and adult diabetic rats. Accordingly, this study was designed to assess the influence of a shorter training program in elderly diabetic fatty rats. MATERIAL/METHODS: Study subjects were 24 male homozygous Zucker diabetic fatty rats (Gmi, fa/fa) aged 18 weeks with an average weight of 370-450 g. After a 2-week period of environmental adaptation, animals were randomly distributed into the Exercised Group (n=12) that performed a 6-week swimming training protocol and the Sedentary Group (n=12). Animals were sacrificed under anesthesia 24 h after the last exercise session. Serum metabolic profile was determined. Total antioxidant status (TAS), MnSOD expression, glutathione status and ROS generation were assayed in gastrocnemius muscle. RESULTS: When compared with controls, exercised rats significantly improved their metabolic profile. Total antioxidant status (0.19±0.002 vs. 0.13±0.002 µg/mg protein; p<0.001) and MnSOD expression (8471±90 vs. 6258±102 U/µg protein; p=0.003) were also increased in exercised rats. CONCLUSIONS: A 6-week swimming training program improved the antioxidant system in elderly fatty diabetic rats. Fortunately, this improvement was enough to reduce oxidative damage, expressed as protein oxidation. A major finding of this study was that our training protocol lasted just 6 weeks, in contrast to longer protocols previously published.

The bactericidal effect of silver nanoparticles.

Nanotechnology is expected to open new avenues to fight and prevent disease using atomic scale tailoring of materials. Among the most promising nanomaterials with antibacterial properties are metallic nanoparticles, which exhibit increased chemical activity due to their large surface to volume ratios and crystallographic surface structure. The study of bactericidal nanomaterials is particularly timely considering the recent increase of new resistant strains of bacteria to the most potent antibiotics. This has promoted research in the well known activity of silver ions and silver-based compounds, including silver nanoparticles. The present work studies the effect of silver nanoparticles in the range of 1-100 nm on Gram-negative bacteria using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). Our results indicate that the bactericidal properties of the nanoparticles are size dependent, since the only nanoparticles that present a direct interaction with the bacteria preferentially have a diameter of approximately 1-10 nm.

Molecular mechanisms of MHC linked susceptibility in leprosy: towards the development of synthetic vaccines.

Tuberculoid (TT) and lepromatous leprosy (LL) develop in the human host depending on his ability to trigger a specific cellular immune response(CIR). Different genes have been demonstrated in susceptibility/protection and may explain the forms of leprosy. The major histocompatibility complex (MHC) play an important role. The aim of the study was to explore the contribution of human leukocyte antigen (HLA) DRB1, DQA1, DQB1 and DQ promoter genes in LL Mexican patients. Six families (26 LL, three TT patients and 27 controls) were analyzed; 114 unrelated patients were compared with 204 controls. Class I typing was done by the standard microlymphocytotoxicity and class II typing using PCR-SSOP. Haplotype segregation correlated with specific CIR in vivo and in vitro using lepromin. Haplotype sharing was significantly deviated in the affected sibs (p=0.01). Six healthy sibs were non-responders to lepromin and four of them were DQ1 homozgotes. DQ1 was significantly associated with LL and with non-responders. We set up macrophage activation experiments after infecting these cells with 5x10(6) bacilli to demonstrate if elimination occurred in the context or DQ1. When DQ1 was present on macrophages and on T cells, bacteria were poorly eliminated from the cell (32%) while when absent, 76% of the individuals were able to eliminate the bacilli (p=0.03). DRB1*1501 DQA1*0102-DQB1*0602 (DQ1 subtype) was significantly increased in the patients, indicating its participation in susceptibility. QBP 5.11/5.12 promoter present in the mentioned haplotype, and QAP 1.4, linked to DRB1*1301/02 haplotypes were also associated. Two mechanisms are suggested: the promoter polymorphisms may influence allele expression and thus the amount of peptides presented to the T-cell receptor, leading to a deficient CIR: HLA restriction is important for vaccine design; the way peptides anchor the DRB1*1501 groove may be relevant to the activation of TH1 cells, which contribute to an efficient presentation of peptides inducing a protective T-cell response.