Modeling bacterial microcompartment architectures for enhanced cyanobacterial carbon fixation.

The carboxysome is a bacterial microcompartment (BMC) which plays a central role in the cyanobacterial CO2-concentrating mechanism. These proteinaceous structures consist of an outer protein shell that partitions Rubisco and carbonic anhydrase from the rest of the cytosol, thereby providing a favorable microenvironment that enhances carbon fixation. The modular nature of carboxysomal architectures makes them attractive for a variety of biotechnological applications such as carbon capture and utilization. In silico approaches, such as molecular dynamics (MD) simulations, can support future carboxysome redesign efforts by providing new spatio-temporal insights on their structure and function beyond in vivo experimental limitations. However, specific computational studies on carboxysomes are limited. Fortunately, all BMC (including the carboxysome) are highly structurally conserved which allows for practical inferences to be made between classes. Here, we review simulations on BMC architectures which shed light on (1) permeation events through the shell and (2) assembly pathways. These models predict the biophysical properties surrounding the central pore in BMC-H shell subunits, which in turn dictate the efficiency of substrate diffusion. Meanwhile, simulations on BMC assembly demonstrate that assembly pathway is largely dictated kinetically by cargo interactions while final morphology is dependent on shell factors. Overall, these findings are contextualized within the wider experimental BMC literature and framed within the opportunities for carboxysome redesign for biomanufacturing and enhanced carbon fixation.

Differential epigenetic effects of chlorpyrifos and arsenic in proliferating and differentiating human neural progenitor cells.

Understanding the underlying temporal and mechanistic responses to neurotoxicant exposures during sensitive periods of neuronal development are critical for assessing the impact of these exposures on developmental processes. To investigate the importance of timing of neurotoxicant exposure for perturbation of epigenetic regulation, we exposed human neuronal progenitor cells (hNPCs) to chlorpyrifos (CP) and sodium arsenite (As; positive control) during proliferation and differentiation. CP or As treatment effects on hNPCs morphology, cell viability, and changes in protein expression levels of neural differentiation and cell stress markers, and histone H3 modifications were examined. Cell viability, proliferation/differentiation status, and epigenetic results suggest that hNPCs cultures respond to CP and As treatment with different degrees of sensitivity. Histone modifications, as measured by changes in histone H3 phosphorylation, acetylation and methylation, varied for each toxicant and growth condition, suggesting that differentiation status can influence the epigenetic effects of CP and As exposures.

Infantile Refsum Disease: Influence of Dietary Treatment on Plasma Phytanic Acid Levels.

Infantile Refsum disease (IRD) is one of the less severe of Zellweger spectrum disorders (ZSDs), a group of peroxisomal biogenesis disorders resulting from a generalized peroxisomal function impairment. Increased plasma levels of very long chain fatty acids (VLCFA) and phytanic acid are biomarkers used in IRD diagnosis. Furthermore, an increased plasma level of phytanic acid is known to be associated with neurologic damage. Treatment of IRD is symptomatic and multidisciplinary.The authors report a 3-year-old child, born from consanguineous parents, who presented with developmental delay, retinitis pigmentosa, sensorineural deafness and craniofacial dysmorphisms. While the relative level of plasma C26:0 was slightly increased, other VLCFA were normal. Thus, a detailed characterization of the phenotype was essential to point to a ZSD. Repeatedly increased levels of plasma VLCFA, along with phytanic acid and pristanic acid, deficient dihydroxyacetone phosphate acyltransferase activity in fibroblasts and identification of the homozygous pathogenic mutation c.2528G>A (p.Gly843Asp) in the PEX1 gene, confirmed this diagnosis. Nutritional advice and follow-up was proposed aiming phytanic acid dietary intake reduction. During dietary treatment, plasma levels of phytanic acid decreased to normal, and the patient's development evaluation showed slow progressive acquisition of new competences.This case report highlights the relevance of considering a ZSD in any child with developmental delay who manifests hearing and visual impairment and of performing a systematic biochemical investigation, when plasma VLCFA are mildly increased. During dietary intervention, a biochemical improvement was observed, and the long-term clinical effect of this approach needs to be evaluated.

Could Mycobacterium leprae Infection Be an Occupational Disease? A Survey in Healthcare Workers From an Endemic Area in the Amazonian Region.

A serologic survey was conducted to evaluate the prevalence of Mycobacterium leprae infection among healthcare workers and associated factors. Of 280 workers, 26 (9.3%) were positive using immunoglobulin M serology for PGL-I M. leprae antigen. Exposure to leprosy patients in the workplace was significantly associated with seropositivity (P=.044).

D-bifunctional protein deficiency: a cause of neonatal onset seizures and hypotonia.

BACKGROUND: Peroxisomal disorders are classified in two major groups: (1) peroxisome biogenesis disorders and (2) single peroxisomal enzyme/transporter deficiencies. D-bifunctional protein deficiency (OMIM #261515) is included in this last group of rare diseases and leads to an impaired peroxisomal beta-oxidation. D-bifunctional protein deficiencies are divided into four types based on the degree of activity of the 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase protein units. PATIENT DESCRIPTION: We present the first Portuguese reported type II D-bifunctional protein deficiency patient, whose neonatal clinical picture is indistinguishable from a Zellweger spectrum disease. The clinical features and the neuroimaging findings of polymicrogyria raised suspicion of the diagnosis. After biochemical analysis, D-bifunctional protein deficiency was confirmed with the identification of a homozygous p.Asn457Tyr (N457Y) mutation of the HSD17B4 gene. The patient's parents were carriers of the mutated allele, confirming the patient homozygosity status and allowing prenatal diagnosis in future pregnancies. CONCLUSIONS: D-bifunctional protein deficiency is a rare, severe disease and the final diagnosis can only be accomplished after HSD17B4 gene sequencing. Treatment is supportive, aimed at improving nutrition and growth, controlling the central nervous system symptoms, and limiting the eventual progression of liver disease.

Improving Post-Discharge Medication Adherence in Patients with CVD: A Pilot Randomized Trial / Otimização da Adesão Terapêutica Pós-alta Hospitalar de Pacientes com DCV: Ensaio Clínico Randomizado - Estudo Piloto

Background: Effective interventions to improve medication adherence are usually complex and expensive. Objective: To assess the impact of a low-cost intervention designed to improve medication adherence and clinical outcomes in post-discharge patients with CVD. Method: A pilot RCT was conducted at a teaching hospital. Intervention was based on the four-item Morisky Medication Adherence Scale (MMAS-4). The primary outcome measure was medication adherence assessed using the eight-item MMAS at baseline, at 1 month post hospital discharge and re-assessed 1 year after hospital discharge. Other outcomes included readmission and mortality rates. Results: 61 patients were randomized to intervention (n = 30) and control (n = 31) groups. The mean age of the patients was 61 years (SD 12.73), 52.5% were males, and 57.4% were married or living with a partner. Mean number of prescribed medications per patient was 4.5 (SD 3.3). Medication adherence was correlated to intervention (p = 0.04) and after 1 month, 48.4% of patients in the control group and 83.3% in the intervention group were considered adherent. However, this difference decreased after 1 year, when adherence was 34.8% and 60.9%, respectively. Readmission and mortality rates were related to low adherence in both groups. Conclusion: The intervention based on a validated patient self-report instrument for assessing adherence is a potentially effective method to improve adherent behavior and can be successfully used as a tool to guide adherence counseling in the clinical visit. However, a larger study is required to assess the real impact of intervention on these outcomes. .

Fundamento: Intervenções eficazes para melhorar a adesão à terapia medicamentosa são geralmente complexas e caras. Objetivo: Avaliar o impacto de uma intervenção de baixo custo delineada para melhorar a adesão à medicação e desfechos clínicos em pacientes no pós-alta com DCV. Método: Um ECR - estudo piloto foi realizado em um hospital-escola. A intervenção foi baseada na escala de adesão terapêutica de Morisky de quatro itens - MMAS-4. O desfecho primário medido foi a avaliação da adesão à medicação utilizando a MMAS de oito itens no momento da alta, 1 mês após a alta hospitalar, e a reavaliação 1 ano depois da alta. Outros resultados incluíram reinternação e as taxas de mortalidade. Resultados: Foram randomizados 61 pacientes para grupos de intervenção (n = 30) e controle (n = 31). A idade média dos pacientes foi de 61 anos (DP 12,73), 52,5% eram do sexo masculino e 57,4% eram casados ou moravam com parceiro (a). O número médio de medicamentos prescritos por paciente foi de 4,5 (DP 3,3). A adesão à medicação foi correlacionada à intervenção (p = 0,04) e após 1 mês, 48,4% dos pacientes do grupo controle e 83,3% no grupo de intervenção foram considerados aderentes. No entanto, essa diferença diminuiu depois de 1 ano, quando a adesão foi de 34,8% e 60,9%, respectivamente. As taxas de readmissão e de mortalidade foram relacionadas à baixa adesão nos dois grupos. Conclusão: A intervenção com base em um instrumento validado de auto-relato do paciente para avaliar a adesão é um método potencialmente eficaz para melhorar o comportamento aderente e pode ser usado com sucesso como uma ferramenta para orientar o aconselhamento da adesão na visita ...

Improving post-discharge medication adherence in patients with CVD: a pilot randomized trial.

BACKGROUND: Effective interventions to improve medication adherence are usually complex and expensive. OBJECTIVE: To assess the impact of a low-cost intervention designed to improve medication adherence and clinical outcomes in post-discharge patients with CVD. METHOD: A pilot RCT was conducted at a teaching hospital. Intervention was based on the four-item Morisky Medication Adherence Scale (MMAS-4). The primary outcome measure was medication adherence assessed using the eight-item MMAS at baseline, at 1 month post hospital discharge and re-assessed 1 year after hospital discharge. Other outcomes included readmission and mortality rates. RESULTS: 61 patients were randomized to intervention (n = 30) and control (n = 31) groups. The mean age of the patients was 61 years (SD 12.73), 52.5% were males, and 57.4% were married or living with a partner. Mean number of prescribed medications per patient was 4.5 (SD 3.3). Medication adherence was correlated to intervention (p = 0.04) and after 1 month, 48.4% of patients in the control group and 83.3% in the intervention group were considered adherent. However, this difference decreased after 1 year, when adherence was 34.8% and 60.9%, respectively. Readmission and mortality rates were related to low adherence in both groups. CONCLUSION: The intervention based on a validated patient self-report instrument for assessing adherence is a potentially effective method to improve adherent behavior and can be successfully used as a tool to guide adherence counseling in the clinical visit. However, a larger study is required to assess the real impact of intervention on these outcomes.

The current status of biomarkers for predicting toxicity.

INTRODUCTION: There are significant rates of attrition in drug development. A number of compounds fail to progress past preclinical development due to limited tools that accurately monitor toxicity in preclinical studies and in the clinic. Research has focused on improving tools for the detection of organ-specific toxicity through the identification and characterization of biomarkers of toxicity. AREAS COVERED: This article reviews what we know about emerging biomarkers in toxicology, with a focus on the 2012 Northeast Society of Toxicology meeting titled 'Translational Biomarkers in Toxicology.' The areas covered in this meeting are summarized and include biomarkers of testicular injury and dysfunction, emerging biomarkers of kidney injury and translation of emerging biomarkers from preclinical species to human populations. The authors also provide a discussion about the biomarker qualification process and possible improvements to this process. EXPERT OPINION: There is currently a gap between the scientific work in the development and qualification of novel biomarkers for nonclinical drug safety assessment and how these biomarkers are actually used in drug safety assessment. A clear and efficient path to regulatory acceptance is needed so that breakthroughs in the biomarker toolkit for nonclinical drug safety assessment can be utilized to aid in the drug development process.

Sperm mRNA transcripts are indicators of sub-chronic low dose testicular injury in the Fischer 344 rat.

Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1) identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD) using microarrays; 2) expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3) test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ). Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q<0.05). All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p<0.05). In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p<0.05). The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat.

Male reprotoxicity and endocrine disruption.

Mammalian reproductive tract development is a tightly regulated process that can be disrupted following exposure to drugs, toxicants, endocrine-disrupting chemicals (EDCs), or other compounds via alterations to gene and protein expression or epigenetic regulation. Indeed, the impacts of developmental exposure to certain toxicants may not be fully realized until puberty or adulthood when the reproductive tract becomes sexually mature and altered functionality is manifested. Exposures that occur later in life, once development is complete, can also disrupt the intricate hormonal and paracrine interactions responsible for adult functions, such as spermatogenesis. In this chapter, the biology and toxicology of the male reproductive tract is explored, proceeding through the various life stages including in utero development, puberty, adulthood, and senescence. Special attention is given to the discussion of EDCs, chemical mixtures, low-dose effects, transgenerational effects, and potential exposure-related causes of male reproductive tract cancers.

Optimization of a filter-lysis protocol to purify rat testicular homogenates for automated spermatid counting.

Quantifying testicular homogenization-resistant spermatid heads (HRSH) is a powerful indicator of spermatogenesis. These counts have traditionally been performed manually using a hemocytometer, but this method can be time consuming and biased. We aimed to develop a protocol to reduce debris for the application of automated counting, which would allow for efficient and unbiased quantification of rat HRSH. We developed a filter-lysis protocol that effectively removes debris from rat testicular homogenates. After filtering and lysing the homogenates, we found no statistical differences between manual (classic and filter-lysis) and automated (filter-lysis) counts using 1-way analysis of variance with Bonferroni's multiple comparison test. In addition, Pearson's correlation coefficients were calculated to compare the counting methods, and there was a strong correlation between the classic manual counts and the filter-lysis manual (r = 0.85, P = .002) and the filter-lysis automated (r = 0.89, P = .0005) counts. We also tested the utility of the automated method in a low-dose exposure model known to decrease HRSH. Adult Fischer 344 rats exposed to 0.33% 2,5-hexanedione in the drinking water for 12 weeks demonstrated decreased body (P = .02) and testes (P = .002) weights. In addition, there was a significant reduction in the number of HRSH per testis (P = .002) when compared to controls. A filterlysis protocol was optimized to purify rat testicular homogenates for automated HRSH counts. Automated counting systems yield unbiased data and can be applied to detect changes in the testis after low-dose toxicant exposure.

Integrative DNA methylation and gene expression analyses identify DNA packaging and epigenetic regulatory genes associated with low motility sperm.

BACKGROUND: In previous studies using candidate gene approaches, low sperm count (oligospermia) has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. METHODS AND RESULTS: Sperm DNA and mRNA were isolated from 21 men with a range of semen parameters presenting to a tertiary male reproductive health clinic. DNA methylation was measured with the Illumina Infinium array at 27,578 CpG loci. Unsupervised clustering of methylation data differentiated the 21 sperm samples by their motility values. Recursively partitioned mixture modeling (RPMM) of methylation data resulted in four distinct methylation profiles that were significantly associated with sperm motility (P = 0.01). Linear models of microarray analysis (LIMMA) was performed based on motility and identified 9,189 CpG loci with significantly altered methylation (Q<0.05) in the low motility samples. In addition, the majority of these disrupted CpG loci (80%) were hypomethylated. Of the aberrantly methylated CpGs, 194 were associated with imprinted genes and were almost equally distributed into hypermethylated (predominantly paternally expressed) and hypomethylated (predominantly maternally expressed) groups. Sperm mRNA was measured with the Human Gene 1.0 ST Affymetrix GeneChip Array. LIMMA analysis identified 20 candidate transcripts as differentially present in low motility sperm, including HDAC1 (NCBI 3065), SIRT3 (NCBI 23410), and DNMT3A (NCBI 1788). There was a trend among altered expression of these epigenetic regulatory genes and RPMM DNA methylation class. CONCLUSIONS: Using integrative genome-wide approaches we identified CpG methylation profiles and mRNA alterations associated with low sperm motility.

Comportamiento de los accidentes en menores de 15 años / Behavior of Accidents in Children Under 15 Years

Se realizó un estudio observacional analítico longitudinal y retrospectivo en el Policlínico Universitario Marta Martínez Figuera del municipio Güines, provincia La Habana. La población objeto de estudio estuvo integrada por 878 niños menores de 15 años que sufrieron accidentes en el transcurso de un año. La incidencia global de accidentes fue de 21,5 por ciento. El sexo masculino fue el más afectado con un 57,6 por ciento. Los grupos etáreos menores de 1 año y de 1 a 4 años presentaron Incidencias específicas iguales, significativamente superiores al grupo de 5 a 14 años. Los factores lesionantes que predominaron fueron los traumatismos y estuvieron presentes en todos los grupos etáreos con un 86,4 por ciento presentando un incremento en los aportes proporcionales a medida que se incrementa la edad y la mayoría de los accidentes ocurrieron en el hogar (AU)

It was conducted a longitudinal, observational and retrospective study, in Marta Martínez Figuera University Polyclinic in Güines Municipality, Havana province. The study population consisted of 878 children under 15 years who suffered accidents in the course of a year. The overall incidence of accidents was 21,5 per cent. The masculine sex was the most affected with 57,6 per cent. The age groups under 1 year and 1-4 years had equal specific incidences, significantly higher than the group of 5-14 years. Injurious factors that predominated were traumatisms and were present in all age groups with 86,4 per cent showing an increase in the proportional contributions as age increases and most accidents occurred at home (AU)

Lugares y síntomas justo antes del accidente en pacientes con fibromialgia primaria / Places and symptoms just before the accident in patients with primary fibromyalgia

Se realizó un estudio observacional analítico retrospectivo longitudinal con grupo control en ambos sexos y más de 15 años de edad a través de una tabla de números aleatorios a los pacientes diagnosticados de fibromialgia primaria en las consultas de reumatología de los Policlínicos Docentes Luis Li Tregent y Martha Martínez Figueras del Municipio Güines en el período comprendido desde el 1ero de septiembre del 2006 al 31 de mayo del 2007. La edad osciló entre los 35 y 44 años, la frecuencia de accidentes en pacientes con fibromialgia primaria fue mayor que en el grupo control y aumentó a medida que pasó el tiempo de aparición de los síntomas. El sueño no reparador y no alcanzar el sueño hasta pasado una hora y más de haberse acostado se relacionó significativamente con una mayor frecuencia de accidentes. La aparición de los síntomas cuatro años atrás, se relacionó significativamente con el número de accidentes en el último año. No existió relación significativa entre los síntomas justo antes del accidente y el lugar donde ocurrió. Fue significativa la relación de la aparición de los síntomas desde hace cuatro años y más con la afectación laboral en el último año (AU)

It was carried out a retrospective longitudinal, analytical and observational study with control group in both sexes and more than 15 years of age through a table of random numbers to patients diagnosed with primary fibromyalgia in rheumatology consultations of Luis Li Tregent and Martha Martinez Figueras teaching polyclinics in Güines Municipality in the period from September 1st 2006 to May 31st, 2007. The age ranged between 35 and 44 years, the frequency of accidents in primary fibromyalgia patients was higher than in the control group and it increased as time passed from the onset of symptoms. The non-restful sleep and not getting asleep after more than an hour of lying in bed it was significantly associated with greater frequency of accidents in the past year. There was no significant relationship between symptoms just before the accident and the place. It was significant the relationship between the onset of symptoms since four years and more with the work affectation in the past year

Efecto del cinc sobre el desarrollo y el crecimiento en ratas con crecimiento intrauterino retardado / Effect of zinc on the development and growth in rats with intrauterine growth retardation

Se realizó un estudio experimental para determinar el efecto del sulfato de cinc sobre el crecimiento postnatal del encéfalo en crías de ratas con Crecimiento Intrauterino Retardado. En esta investigación se utilizaron 20 ratas hembras de la línea Sprague Dawley, a las que se les realizó la ligadura de las arterias de ambos cuernos uterinos el día 16 de la gestación (modelo experimental de crecimiento intrauterino retardado). Cien crías se obtuvieron por vía vaginal el día 21 de la preñez y se asignaron aleatoriamente a dos grupos: 50 experimental y 50 control. A las crías del grupo experimental se les administró por vía oral con cánula esofágica una solución de sulfato de cinc al 1 por ciento (5 mg/ kg de peso corporal, equivalente a dos gotas dos veces al día) al nacer, a los 3 y a los 7 días. Por su parte, a las crías del grupo control se les suministró una solución de cloruro de sodio 0,9 por ciento, utilizando iguales vía y momentos de administración que en el grupo experimental. Entre los principales resultados se determinó el efecto positivo del sulfato de cinc sobre el peso, talla y diámetro anteroposterior y biparietal de los cráneos a los 7 y 14 días de nacidas con diferencias estadísticamente significativas (p<0,005)(AU)

An experimental study was carried out to determine the effect of zinc sulfate on the postnatal encephalo growth in a rat litter with intrauterine growth retardation (IUGR). Twenty female rats of the line Sprague Dawley were used in these investigation, which underwent artery ligation of both uterine horns on the 16th day of gestation (experimental model of intrauterine growth retardation). A hundred rat's young were obtained via vagina on the 21st day of pregnancy and they were randomly assigned to two groups: 50 experimental and 50 control. A 1per cent zinc sulfate solution was orally administered with esophagic cannula to the litter of the experimental group (5 mg/ kg of body weight, equivalent to two drops twice a day) at 3 and 7 days of birth. A 0,9 per cent sodium chloride solution was administered to the the litter of the control group using the same via, and moments of administration than in the experimental group. Among the main results it was determined the positive effect of zinc sulfate on the weight, size and antero-posterior and biparietal diameter of the craniums at 7 and 14 days of birth with significant statistical differences (p<0,005)(AU)