Maple syrup urine disease: Characteristics of diagnosis and treatment in 45 patients in Chile.

Maple urine syrup disease (MSUD) is an autosomal recessive disorder characterized by deficient activity of the branched-chain alpha ketoacid dehydrogenase (BCKAD) enzymatic complex due to biallelic variants in the alpha (BCKDHA) or beta (BCKDHB) subunits or the acyltransferase component (DBT). Treatment consists in leucine (LEU), isoleucine (ILE), and valine (VAL) (branched-chain amino acids) dietary restriction and strict metabolic control. to determine the characteristics of the Chilean cohort with MSUD currently in follow-up at Instituto de Nutrición y Tecnología de los Alimentos, during the 1990-2017 period Retrospective analytical study in 45 MSUD cases. Measured: biochemical parameters (LEU, ILE, and VAL), anthropometric evaluation, and neurocognitive development. In 18 cases undergoing genetic study were analyzed according to the gene and protein location, number of affected alleles, and type of posttranslational modification affected. Then, 45 patients with MSUD diagnosis were identified during the period: 37 were alive at the time of the study. Average diagnosis age was 71 ± 231 days. Average serum diagnosis LEU concentrations: 1.463 ± 854.1 µmol/L, VAL 550 ± 598 µmol/L and ILE 454 ± 458 µmol/L. BCKDHB variants explain 89% cases, while BCKDHA and DBT variants explain 5.5% of cases each. Variants p.Thr338Ile in BCKDHA, p.Pro240Thr and p.Ser342Asn in BCKDHB have not been previously reported in literature. Average serum follow-up LEU concentrations were 252.7 ± 16.9 µmol/L in the <5 years group and 299 ± 123.2 µmol/L in ≥5 years. Most cases presented some degree of developmental delay. Early diagnosis and treatment is essential to improve the long-term prognosis. Frequent blood LEU measurements are required to optimize metabolic control and to establish relationships between different aspects analyzed.

Melanocytes and melanin represent a first line of innate immunity against Candida albicans.

Melanocytes are dendritic cells located in the skin and mucosae that synthesize melanin. Some infections induce hypo- or hyperpigmentation, which is associated with the activation of Toll-like receptors (TLRs), especially TLR4. Candida albicans is an opportunist pathogen that can switch between blastoconidia and hyphae forms; the latter is associated with invasion. Our objectives in this study were to ascertain whether C. albicans induces pigmentation in melanocytes and whether this process is dependent on TLR activation, as well as relating this with the antifungal activity of melanin as a first line of innate immunity against fungal infections. Normal human melanocytes were stimulated with C. albicans supernatants or with crude extracts of the blastoconidia or hyphae forms, and pigmentation and TLR2/TLR4 expression were measured. Expression of the melanosomal antigens Melan-A and gp100 was examined for any correlation with increased melanin levels or antifungal activity in melanocyte lysates. Melanosomal antigens were induced earlier than cell pigmentation, and hyphae induced stronger melanization than blastoconidia. Notably, when melanocytes were stimulated with crude extracts of C. albicans, the cell surface expression of TLR2/TLR4 began at 48 h post-stimulation and peaked at 72 h. At this time, blastoconidia induced both TLR2 and TLR4 expression, whereas hyphae only induced TLR4 expression. Taken together, these results suggest that melanocytes play a key role in innate immune responses against C. albicans infections by recognizing pathogenic forms of C. albicans via TLR4, resulting in increased melanin content and inhibition of infection.

Benzene-1,3,5-tri-carb-oxy-lic acid-pyridinium-2-olate (1/3).

The asymmetric unit of the title compound, C9H6O6·3C5H5NO, contains one benzene-1,3,5-tri-carb-oxy-lic acid mol-ecule (BTA) and three pyridin-2-ol mol-ecules each present in the zwitterion form. In the crystal, these entities are linked through O-H⋯O(-) and N(+)-H⋯O(-) hydrogen bonds, forming sheets parallel to (10-1). These layers contain macrocyclic rings of composition [BTA]2[pyol]6 and with graph-set notation R (6) 8(44), which are stacked along c through π-π inter-actions [inter-centroid distances = 3.536 (2)-3.948 (3) Å]. They are inter-connected by N(+)-H⋯O(-) hydrogen-bonded chains of pyridin-2-ol mol-ecules running parallel to c, forming a three-dimensional network. There are also C-H⋯O hydrogen bonds present which reinforce the three-dimensional structure.

Prevalencia de tabaquismo y actitud de cambio frente al hábito tabáquico en universitarios chilenos: importancia de la formación médica / Prevalence of smoking and attitude towards quitting among university students: the importance of medical training

Chile la tasa de tabaquismo en individuos entre 17 y 24 años es de 55 por ciento. A medida que los estudiantes de Medicina avanzan en su carrera, el conocimiento acerca del tabaquismo como determinante de enfermedad aumenta. Sin embargo, los estudiantes de cursos superiores fuman más que aquellos de cursos iniciales. Objetivo: Determinar la prevalencia de tabaquismo y la actitud de cambio frente al hábito tabáquico en estudiantes de Medicina e Ingeniería, de primer y cuarto año de la Universidad de Chile. Material y método: Estudio descriptivo-transversal. Se utilizó un cuestionario autoadministrado, registrándose variables demográficas, conducta fumadora y actitud de cambio frente al hábito tabáquico. Resultados: La muestra estuvo constituida por490 estudiantes (28,6 por ciento mujeres). La prevalencia actual de tabaquismo fue 18,6 por ciento (17,9 por ciento en mujeres y 18,9 por ciento en hombres, pns). En Medicina la prevalencia actual de tabaquismo fue 21,4 por ciento, en Ingeniería 16,6 por ciento (p<0,01). En ambas carreras los primeros años tuvieron una tasa similar (18,2 por ciento Medicina y 16,8 por ciento Ingeniería, pns). Esta cifra se mantuvo en cuarto año de Ingeniería (16,3 por ciento), pero aumentó significativamente en cuarto año de Medicina (24,3 por ciento). Los estudiantes de Medicina tienen un comportamiento más dinámico en su conducta fumadora que los de Ingeniería. El patrón de conducta tabáquica en mujeres es potencialmente menos dañino que en hombres. Discusión: El conocimiento médico de los efectos nocivos del tabaco no desempeña un rol en disminuir las tasas de tabaquismo. Resulta necesario potenciar en las facultades de Medicina actividades preventivas relacionadas al consumo de tabaco.

Introduction: Smoking is the greatest determinant of public health problems. In Chile, the rate of smoking in individuals between 17 and 24 years is 55 per cent. As medical students advance in their studies, their knowledge of smoking as a determinant of disease increases. Nevertheless, students from more advanced class levels smoke more than those of lower levels. Objective: Determine the prevalence of smoking and the attitude towards quitting in medical and engineering students, in their first and fourth years of studies at the University of Chile. Material and method: Cross sectional descriptive study. A self-administered survey was used, recording demographic variables, smoking behavior, and attitude towards quitting. Results: The sample consisted of 490 students (28.6 percent women). The prevalence of smoking was 18.6 per cent (17.9 percent in women and 18.9 percent in men, p=ns). Among medical students, the prevalence of smoking was 21.4 percent; among engineering students it was 16.6 percent (p<0.01). In both areas the first year students had a similar rate (18.2 percent in medical students and 16.8 percent in engineering, p=ns). This rate was maintained in fourth year engineering students (16.3 percent), but increased significantly in fourth year medical students (24.3 percent). Medical students have a more dynamic attitude towards their smoking habit than engineering students. The pattern of tobacco behavior in women is potentially more harmful than in men. Discussion: Medical knowledge of the harmful effects of tobacco doesn't play a role in decreasing the rates of smoking. It is necessary to promote preventive activities related to the consumption of tobacco in medical schools.

Olfactory or auditory stimulation and their hedonic valúes differentially modulate visual working memory

Working memory (WM) designates the retention of objects or events in conscious awareness when these are not present in the environment. Many studies have focused on the interference properties of distracter stimuli in working memory, but these studies have mainly examined the influence of the intensity of these stimuli. Little is known about the memory modulation of hedonic content of distracter stimuli as they also may affect WM performance or attentional tasks. In this paper, we have studied the performance of a visual WM task where subjects recollect from five to eight visually presented objects while they are simultaneously exposed to additional - albeit weak- auditory or olfactory distracter stimulus. We found that WM performance decreases as the number of items to remember increases, but this performance was unaltered by any of the distracter stimuli. However, when performance was correlated to the subject's perceived hedonic values, distracter stimuli classified as negative exhibit higher error rates than positive, neutral or control stimuli. We demonstrate that some hedonic content of otherwise neutral stimuli can strongly modulate memory processes.

Olfactory or auditory stimulation and their hedonic values differentially modulate visual working memory.

Working memory (WM) designates the retention of objects or events in conscious awareness when these are not present in the environment. Many studies have focused on the interference properties of distracter stimuli in working memory, but these studies have mainly examined the influence of the intensity of these stimuli. Little is known about the memory modulation of hedonic content of distracter stimuli as they also may affect WM performance or attentional tasks. In this paper, we have studied the performance of a visual WM task where subjects recollect from five to eight visually presented objects while they are simultaneously exposed to additional - albeit weak- auditory or olfactory distracter stimulus. We found that WM performance decreases as the number of Items to remember increases, but this performance was unaltered by any of the distracter stimuli. However, when performance was correlated to the subject's perceived hedonic values, distracter stimuli classified as negative exhibit higher error rates than positive, neutral or control stimuli. We demonstrate that some hedonic content of otherwise neutral stimuli can strongly modulate memory processes.