Minimal and hybrid hydrogenases are active from archaea.

Microbial hydrogen (H2) cycling underpins the diversity and functionality of diverse anoxic ecosystems. Among the three evolutionarily distinct hydrogenase superfamilies responsible, [FeFe] hydrogenases were thought to be restricted to bacteria and eukaryotes. Here, we show that anaerobic archaea encode diverse, active, and ancient lineages of [FeFe] hydrogenases through combining analysis of existing and new genomes with extensive biochemical experiments. [FeFe] hydrogenases are encoded by genomes of nine archaeal phyla and expressed by H2-producing Asgard archaeon cultures. We report an ultraminimal hydrogenase in DPANN archaea that binds the catalytic H-cluster and produces H2. Moreover, we identify and characterize remarkable hybrid complexes formed through the fusion of [FeFe] and [NiFe] hydrogenases in ten other archaeal orders. Phylogenetic analysis and structural modeling suggest a deep evolutionary history of hybrid hydrogenases. These findings reveal new metabolic adaptations of archaea, streamlined H2 catalysts for biotechnological development, and a surprisingly intertwined evolutionary history between the two major H2-metabolizing enzymes.

Rubisco Function, Evolution, and Engineering.

Carbon fixation is the process by which CO2 is converted from a gas into biomass. The Calvin-Benson-Bassham cycle (CBB) is the dominant carbon-consuming pathway on Earth, driving >99.5% of the ∼120 billion tons of carbon that are converted to sugar by plants, algae, and cyanobacteria. The carboxylase enzyme in the CBB, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco), fixes one CO2 molecule per turn of the cycle into bioavailable sugars. Despite being critical to the assimilation of carbon, rubisco's kinetic rate is not very fast, limiting flux through the pathway. This bottleneck presents a paradox: Why has rubisco not evolved to be a better catalyst? Many hypothesize that the catalytic mechanism of rubisco is subject to one or more trade-offs and that rubisco variants have been optimized for their native physiological environment. Here, we review the evolution and biochemistry of rubisco through the lens of structure and mechanism in order to understand what trade-offs limit its improvement. We also review the many attempts to improve rubisco itself and thereby promote plant growth.

Borgs are giant genetic elements with potential to expand metabolic capacity.

Anaerobic methane oxidation exerts a key control on greenhouse gas emissions1, yet factors that modulate the activity of microorganisms performing this function remain poorly understood. Here we discovered extraordinarily large, diverse DNA sequences that primarily encode hypothetical proteins through studying groundwater, sediments and wetland soil where methane production and oxidation occur. Four curated, complete genomes are linear, up to approximately 1 Mb in length and share genome organization, including replichore structure, long inverted terminal repeats and genome-wide unique perfect tandem direct repeats that are intergenic or generate amino acid repeats. We infer that these are highly divergent archaeal extrachromosomal elements with a distinct evolutionary origin. Gene sequence similarity, phylogeny and local divergence of sequence composition indicate that many of their genes were assimilated from methane-oxidizing Methanoperedens archaea. We refer to these elements as 'Borgs'. We identified at least 19 different Borg types coexisting with Methanoperedens spp. in four distinct ecosystems. Borgs provide methane-oxidizing Methanoperedens archaea access to genes encoding proteins involved in redox reactions and energy conservation (for example, clusters of multihaem cytochromes and methyl coenzyme M reductase). These data suggest that Borgs might have previously unrecognized roles in the metabolism of this group of archaea, which are known to modulate greenhouse gas emissions, but further studies are now needed to establish their functional relevance.

Malnutrition risk and associated factors in hospitalized older adult patients with neurological diseases: a retrospective cohort study.

INTRODUCTION: Malnutrition risk (MR) in older adults with neurological disorders is high, but there is little evidence for validated screening tools in this group, as well as for the clinical and socioeconomic factors associated with a high MR. OBJECTIVES: To determine the association of MR using the Malnutrition Universal Screening Tool (MUST) with mortality and length of stay (LOS) in older adults with neurological diseases. Secondarily, the association of clinical, and socioeconomic factors with MR and clinical outcomes was sought. METHODS: A retrospective cohort study was carried out at a third-level neurological disease referral center in Mexico. All patients older than 60 years admitted from January 2017 to December 2018 were considered. MUST, clinical and socioeconomic factors were assessed at hospital admission. Outcomes were followed up to hospital discharge or a maximum of 6 months. RESULTS: A total of 765 patients were included, of whom 24.7% (n = 189) were at high risk. A high MR was independently associated with mortality (OR 3.09; 95% CI 1.60-5.98, p = .001) and LOS >14 days (OR 4.38; 95% CI 2.79-6.89, p = <.001). The only factors independently associated with high MR was economic dependence and unemployment. Patients with high MR and economic dependence (OR 4.0; 95% CI 1.34-11.99, p = .013) or unemployment (OR 3.43; 95% CI 1.17-10.06, p = .025) had the highest mortality. CONCLUSIONS: In hospitalized older adults with neurological diseases, high MR is independently associated with increased mortality and LOS. Economic dependence or unemployment are associated with worse clinical outcomes in patients with high MR.

Does bioabsorbable mesh reduce hiatal hernia recurrence rates? A meta-analysis.

INTRODUCTION: The use of bioabsorbable mesh at the hiatus is controversial. Long-term data are scant. We evaluated the world literature and performed a meta-analysis to determine if these meshes were effective in reducing recurrence. METHODS: A literature search was performed using PubMed, MEDLINE, and ClinicalKey. We evaluated articles reporting on both Bio-A™ (polyglycolic acid:trimethylene carbonate-PGA:TMC) and Phasix™ (poly-4-hydroxybutyrate-P4HB) used at the hiatus. The DerSimonian-Laird random effects model was used to estimate the overall pooled treatment effect along with a 95% confidence interval (CI). Similar analysis was conducted to compare the clinical outcomes, i.e., recurrence rate, mean surgical time, mean hospital stays and mean follow-up duration between non-Mesh and Mesh group. The I2 statistic was computed to assess the heterogeneity in effect sizes across the studies. RESULTS: A total of 21 studies (12 mesh studies with 963 subjects and 9 non-mesh studies with 617 subjects) were included to conduct the meta-analysis. There was one article reporting outcomes on P4HB mesh (73 subjects) and 11 on PGA:TMC mesh (890 subjects). The bioabsorbable mesh group had a significantly lower recurrence rate compared to the non-mesh group (8% vs. 18%; 95%CI 0.08-0.17), pooled p-value < 0.0001. Surgery time was shorter in the mesh group compared to the non-mesh group (136.4 min vs. 150 min) but not statistically significant (p = 0.54). There tended to be a more extended follow-up period after surgery in the non-mesh group compared to the mesh group (27 vs. 25.8 months, range 10.8-54 months); but not statistically significant (ES: 27.4; 95%CI 21.6-33.3; p = 0.92). CONCLUSIONS: Hiatal hernia repair with bioabsorbable mesh is more effective at reducing hernia recurrence rate in the mid-term than simple suture cruroplasty. Further studies investigating the long-term outcomes and P4HB mesh are needed.

Length of Maternity Leave Impact on Mental and Physical Health of Mothers and Infants, a Systematic Review and Meta-analysis.

BACKGROUND: Recent legislative decisions in the United States have encouraged discussion about national parental leave programs. Currently, over 47% of the United States workforce is female. However, the United States is the only nation of the 37 member countries in the Organization for Economic Co-Operation and Development (OECD) to have no national requirement for maternity leave. The first few months of a child's life are vital to their physical and mental development. Likewise, a gradual return to pre-partum functioning is important for a newly postpartum woman. While it has been shown that maternity leave positively impacts various measures of maternal and infant mental and physical health, we lack consensus on the optimal length of paid or unpaid maternity leave. Accordingly, we conducted a systematic review and meta-analysis to evaluate the optimal length of paid or unpaid maternity leave to encourage maternal and infant mental and physical health in the United States. METHODS: A systematic review and meta-analysis were conducted to synthesize and critically evaluate the current research investigating the association between maternity leave and maternal and infant mental and physical health using the Preferred Reporting in Systematic Reviews and Meta-Analyses guidelines. Databases EMBASE, PsycInfo, and PubMed were searched using specific inclusion and exclusion criteria. Methodological Index for Non-Randomized Studies scale assessed the methodological quality of the included eligible studies. The magnitude of heterogeneity between-study was tested using The Cochrane χ2 test and the Moran's I2 statistic. Possible publication bias was assessed through the funnel plot and the Egger regression test. A p-value of < 0.10 will be considered as an indication for the existence of potential publication bias. All statistical analyses were carried out with Stata software version 15. RESULTS: A total of 21 studies were analyzed. It was found that longer maternity leave may decrease rates of maternal mental and physical health complaints. It was also found that longer maternity leave leads to more positive mother-child interactions, decreased infant mortality, and longer periods of breastfeeding. CONCLUSION: Maternity leave of 12 weeks or more confers the greatest benefit for mothers and their infants.

Minimal cobalt metabolism in the marine cyanobacterium Prochlorococcus.

Despite very low concentrations of cobalt in marine waters, cyanobacteria in the genus Prochlorococcus retain the genetic machinery for the synthesis and use of cobalt-bearing cofactors (cobalamins) in their genomes. We explore cobalt metabolism in a Prochlorococcus isolate from the equatorial Pacific Ocean (strain MIT9215) through a series of growth experiments under iron- and cobalt-limiting conditions. Metal uptake rates, quantitative proteomic measurements of cobalamin-dependent enzymes, and theoretical calculations all indicate that Prochlorococcus MIT9215 can sustain growth with less than 50 cobalt atoms per cell, ∼100-fold lower than minimum iron requirements for these cells (∼5,100 atoms per cell). Quantitative descriptions of Prochlorococcus cobalt limitation are used to interpret the cobalt distribution in the equatorial Pacific Ocean, where surface concentrations are among the lowest measured globally but Prochlorococcus biomass is high. A low minimum cobalt quota ensures that other nutrients, notably iron, will be exhausted before cobalt can be fully depleted, helping to explain the persistence of cobalt-dependent metabolism in marine cyanobacteria.

Repetitive transcranial magnetic stimulation for generalized anxiety and panic disorders: A systematic review and meta-analysis.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is an FDA-approved, noninvasive modality for treating major depressive disorder and obsessive-compulsive disorder. Earlier studies evaluating therapeutic effects of rTMS on symptom scores of patients with generalized anxiety disorder (GAD) and panic disorder (PD) have yielded inconsistent findings. METHODS: We performed a systematic review and meta-analysis of interventional studies assessing the effect of rTMS on symptom scores in patients with GAD or PD with or without psychiatric comorbidities using studies published up to April 2021. We used DerSimonian-Laird random effects models to obtain pooled standardized mean difference (SMD) and 95% CI. RESULTS: A total of 13 studies consisting of 677 participants (404 treated with rTMS and 273 without rTMS) were included in this meta-analysis. In GAD patients with or without any comorbidities, rTMS therapy demonstrated significant improvements in anxiety (SMD = 1.45; P < .001) and depression (SMD = 1.65; P < .001) scores regardless of rTMS parameters. Overall anxiety (SMD = 0.24; P = .48) and panic severity (SMD = 1.19; P = .054) scores did not significantly improve after rTMS therapy in patients with PD. CONCLUSIONS: rTMS is safe and improves anxiety and depression scores only in GAD patients, regardless of underlying comorbidities or rTMS parameters.

Fluid balance assessment in pediatric hemodialysis patients by using whole-body bioimpedance spectroscopy (WB-BIS).

BACKGROUND: Fluid overload is a major factor in morbidity and mortality in dialysis patients. Whole-body bioimpedance spectroscopy (WB-BIS) is a noninvasive method for assessing fluid status. We hypothesized that fluid status measurement of changes in total body water (TBW), extracellular fluid (ECF), and intracellular fluid (ICF) by WB-BIS would correlate with the weight (Wt) changes before and after hemodialysis (HD) and the amount of ultrafiltration (UF) in pediatric HD patients. We also examined the relationship between the ECF percent of total body water (ECF%) and ECF/ICF ratio with the pre-HD systolic blood pressure percentile (SBP%ile). METHODS: WB-BIS measurements were made both before and after HD on three separate occasions in each patient. Pre- and post-HD Wt, BP, and UF volumes were collected on the day of BIS measurement. RESULTS: At total of 96 measurements were obtained from 16 HD patients. There were 6 females (mean age: 13.2 ± 4.5 yrs). UF correlated with changes in weight, TBW and ECF (p < 0.001) but not with ICF changes (p = 0.345). Pre-HD SBP%ile correlated with ECF%. CONCLUSIONS: Our findings suggest that WB-BIS can be used to monitor the fluid status in pediatric HD patients. The fluid that is removed from the patient during the HD treatment primarily comes from the ECF and not the ICF. Mobilization of fluid from the ICF appears to be delayed. Patients with significantly higher pre-HD ECF% and ECF/ICF ratio had higher pre-HD systolic BP. A higher resolution version of the Graphical abstract is available as Supplementary information.

Trends and outcomes of minimally invasive surgery for gastrointestinal stromal tumors (GIST).

OBJECTIVE: Minimally invasive surgery (MIS) is increasingly being utilized for the resection of gastrointestinal cancers. National trends for perioperative and oncologic outcomes of MIS for gastrointestinal stromal tumors (GIST) are unknown. We hypothesized that with increased use of MIS, the perioperative outcomes and survival for GIST are preserved. METHODS: The National Cancer Database (2010-2016) was utilized to assess perioperative and oncologic outcomes for GIST of the stomach and small bowel. Kaplan-Meier method and log rank test were used to compare survival outcomes. RESULTS: Data from 8923 gastric and 3683 small bowel resections were analyzed. Over the study period, MIS became the prevalent modality for gastrectomies (2010: robotic: 2.4%, laparoscopic: 26.1%, open: 71.5% vs. 2016: robotic: 9.6%, laparoscopic: 48.8%, open: 41.6%; p < 0.001), with a smaller increase in enterectomies (2010: robotic: 1%, laparoscopic: 17.3%, open: 81.6% vs. 2016: robotic: 3.9%, laparoscopic: 27.2%, open: 68.9%; p < 0.001). Age and Charlson comorbidity index were similar among groups. MIS approaches were associated with fewer readmissions and lower 90 day mortality for gastrectomies and similar rates for enterectomies. MIS did not compromise patient survival even in patients who underwent neoadjuvant treatment or harbored tumors ≥ 10 cm. CONCLUSION: Minimally invasive surgery is increasingly being utilized for resection of gastric and small bowel GIST, with improved postoperative outcomes. In this retrospective review, overall survival after minimally invasive or open surgery was comparable, even in challenging scenarios of neoadjuvant treatment or large tumors (≥ 10 cm).

Parathyroidectomy Versus Cinacalcet for the Treatment of Secondary Hyperparathyroidism in Hemodialysis Patients.

BACKGROUND: Secondary hyperparathyroidism in patients with end stage renal disease on dialysis is associated with bone pain and fractures in addition to cardiovascular morbidity. Cinacalcet is the most commonly used drug to treat such patients, but it has never been compared to surgery. The goal of this study is to compare the long-term outcomes and survival between cinacalcet and parathyroidectomy in the treatment of secondary hyperparathyroidism in hemodialysis patients. METHODS: Adult patients on hemodialysis who were treated with cinacalcet or parathyroidectomy in the United States Renal Data System were included. Patients treated with surgery (n = 2023) were compared using 1:1 propensity score matching ratio to a cohort of patients treated with cinacalcet. A Cox regression analysis was conducted to compare the overall mortality. RESULTS: The propensity score matching successfully created two groups with similar demographics. Patients in the surgery group had a higher mean peak PTH level prior to therapy (2066.8 vs 1425.4, P < 0.001). No difference was observed in the development of new-onset coronary artery disease (7.7% vs 7.9%, P = 0.8) or cerebrovascular disease (7% vs 6.7%, P = 0.8). Surgical patients had a higher rate of pathologic fractures (27.8% vs 24.9%, P = 0.04). Survival analysis showed that patients undergoing surgery had a better 5-year survival (65.6% vs 57.8%) and were less likely to die within the study period (HR 0.77, 95% CI 0.7-0.85, P < 0.0001). CONCLUSIONS: Patients on dialysis undergoing parathyroidectomy for the treatment of secondary hyperparathyroidism have a better overall survival than those treated with cinacalcet.

Gliomas of the Optic Nerve: A SEER-Based Epidemiologic Study.

BACKGROUND: To determine whether patients with biopsy-confirmed optic nerve glioma differ in clinical features and outcomes from those diagnosed by neuroradiologic imaging alone. METHODS: Retrospective comparative analysis. Pilocytic astrocytomas (PAs) and gliomas of the optic nerve were identified through ICD-O codes in the Surveillance, Epidemiology, and End Results (SEER) cancer registry from 1975 through 2017. Demographics, clinical features, and outcomes were compared according to the method of diagnosis (biopsy-confirmed and radiologic only) and by age (birth through 19 years and 20 years of age and older). Differences in proportions were tested with the chi-square test. Associations with tumor-related death were evaluated with logistic regression. Statistical significance: α < 0.01. RESULTS: Over 42 years, 313 PAs and 720 gliomas of the optic nerve were identified. The young age distributions were similar between the 2 groups. PAs were biopsied more often than gliomas (54% vs 13.2% [ P < 0.001]). Tumor-attributable death occurred more often among PAs and gliomas that were biopsied than those that were not (7.1% vs 0.7% [ P < 0.01]; 7.4% vs 1.1% [ P < 0.01], respectively). Roughly 15% of both PAs and gliomas were diagnosed in persons 20 years and older. CONCLUSIONS: Biopsy-confirmed cases of PA and glioma of the optic nerve were associated with more therapeutic interventions and worse outcomes compared with patients who were diagnosed radiologically. Clinical variables relevant to clinical decision-making not captured by SEER likely explain the inability to meaningfully interpret outcome from the registry database. Cancer registries should avoid coding specific histopathologic diagnoses when tissue is not obtained.

Separation of short and medium-chain fatty acids using capillary electrophoresis with indirect photometric detection: Part I: Identification of fatty acids in rat feces.

Short and medium-chain fatty acids (SMCFAs) are known as essential metabolites found in gut microbiota that function as modulators in the development and progression of many inflammatory conditions as well as in the regulation of cell metabolism. Currently, there are few simple and low-cost analytical methods available for the determination of SMCFA. This report focuses on SMCFA analysis utilizing CE with indirect photometric detection (CE-IPD). A ribonucleotide electrolyte, 5'-adenosine mono-phosphate (5'-AMP), is investigated as an IPD reagent due to its high molar absorptivity and dynamic reserve compatible with separation and detection of SMCFA. The operating parameters like the composition of organic solvent, millimolar concentrations of the complexing agent (alpha-cyclodextrin), 5'-AMP and non-absorbing electrolyte (boric acid), as well as the applied voltage, are optimized for resolution, efficiency, and signal-to-noise ratio. A baseline resolution of all nine SMCFAs is achieved in less than 15 min. Additionally, the developed CE-IPD method shows promising potential to identifying SMCFA in rat fecal supernatant. The presented analytical assay is simple, economical, and has considerably good repeatability. The intraday and interday RSD of less than 1 and 2% for relative migration time, as well as less than 14 and 15% for peak area, respectively, were obtained for SMCFA in fecal solution.

Ethnic Differences Between Hispanics and Non-Hispanic Whites in Neuropsychiatric Symptoms Predict Conversion to Mild Cognitive Impairment.

The aim of the study is to ascertain the neuropsychiatric symptoms (NPS) subtypes significantly influencing progression to mild cognitive impairment (MCI) by ethnicity. In this retrospective cohort study, we included 386 cognitively normal individuals participating in the longitudinal Texas Alzheimer's Research and Care Consortium between February 2007 and August 2014. The primary outcome was time to incident MCI. Data driven NPS subtypes at baseline were identified and the effects of these subtypes on the outcome were obtained for Hispanic and non-Hispanic ethnic cohorts and summarized with a hazard ratio (HR). Three NPS subtypes were identified and internally validated: psychomotor apathy factor (including agitation, irritability, apathy), affective mood factor (including depression, anxiety), and physical behavior factor (including nighttime behavior, eating/appetite disturbances). In adjusted analysis, a psychomotor apathy score of NPS was the best predictor for MCI (HR = 2.19, p = 0.037) among non-Hispanics whereas physical behavior score was the most predictive of MCI (HR = 2.55, p = 0.029) among Hispanics. A high score of affective mood factor also tended to increase the risk of MCI (HR = 2.09, p = 0.06) in Hispanics. Progression from normal cognition to MCI was differentially predicted by NPS subtypes in Hispanics and non-Hispanic whites. These data may inform the allocation of efforts for monitoring individuals at-risk of MCI.

Hydrodynamics and mathematical modelling in a low HRT inverse fluidized-bed reactor for biological sulphate reduction.

Biological reduction of sulphate at low hydraulic retention time (HRT) is presented in this paper. A sulphidogenic inverse fluidized-bed bioreactor (IFBB) was operated successfully at a progressively decreasing HRT from 1 to 0.125 days for a total of 155 days. Synthetic wastewater containing sulphate at a concentration of 745 (± 17) mg/L was used. COD was supplied as lactate in variable concentrations at COD/SO42- ratios of 1.2-2.4. The pH of the feed ranged between 5.2 and 6.2. The highest measured removal rates were 2646 and 4866 mg SO42-/L day at an HRT of 0.25 and 0.125 days, respectively, using a COD/SO42- ratio of 2.3. The biological sulphate reduction was limited by the influent COD concentrations at a COD/SO42- ratio < 2.3. The IFBB ensured biomass retention at a maximum liquid residence time of θ = 3.84 (± 0.013), according to the residence time distribution analysis. Hydrodynamic studies were carried out at recirculation rates of 0, 200, 300, 350, 400, and 500 L/h to measure the relative bed expansion, the mixing pattern, and the fluidization characteristics of the reactor. A dynamic model is also developed based on COD and sulphate as the two limiting substrates in a Monod-type kinetic equation describing the kinetics of lactate oxidation by SRB. A set of the following parameters [Formula: see text] = 0.23 mg COD of VSS/mg lactate, µmax = 1.758 day- 1, KCOD = 956 mg COD of lactate/L, [Formula: see text] = 316 mg SO42-/L, kd = 0.024 day- 1, tres = 5.7 days, and kexchange = 0.4 day- 1 simulated adequately the residual effluent COD and sulphate concentrations, the produced sulphide concentration as well as the pH of the IFBB effluent. Low HRT values, shown efficient in this study, are prerequisite for industrial applicability and economic feasibility of the sulphur reduction process. In addition, the developed model can be used for optimum experimental design and further process upscale and development.

Analysis of small sample size studies using nonparametric bootstrap test with pooled resampling method.

Experimental studies in biomedical research frequently pose analytical problems related to small sample size. In such studies, there are conflicting findings regarding the choice of parametric and nonparametric analysis, especially with non-normal data. In such instances, some methodologists questioned the validity of parametric tests and suggested nonparametric tests. In contrast, other methodologists found nonparametric tests to be too conservative and less powerful and thus preferred using parametric tests. Some researchers have recommended using a bootstrap test; however, this method also has small sample size limitation. We used a pooled method in nonparametric bootstrap test that may overcome the problem related with small samples in hypothesis testing. The present study compared nonparametric bootstrap test with pooled resampling method corresponding to parametric, nonparametric, and permutation tests through extensive simulations under various conditions and using real data examples. The nonparametric pooled bootstrap t-test provided equal or greater power for comparing two means as compared with unpaired t-test, Welch t-test, Wilcoxon rank sum test, and permutation test while maintaining type I error probability for any conditions except for Cauchy and extreme variable lognormal distributions. In such cases, we suggest using an exact Wilcoxon rank sum test. Nonparametric bootstrap paired t-test also provided better performance than other alternatives. Nonparametric bootstrap test provided benefit over exact Kruskal-Wallis test. We suggest using nonparametric bootstrap test with pooled resampling method for comparing paired or unpaired means and for validating the one way analysis of variance test results for non-normal data in small sample size studies. Copyright © 2017 John Wiley & Sons, Ltd.

Carbohydrate based polymeric materials as slow release electron donors for sulphate removal from wastewater.

Many industrial sulphate rich wastewaters are deficient in electron donors to achieve complete sulphate removal. Therefore, pure and expensive chemicals are supplied externally. In this study, carbohydrate based polymers (CBP) as potato (2 and 5 mm3), filter paper (2 and 5 mm2) and crab shell (2 and 4 mm Ø) were tested as slow release electron donors (SRED) for biological sulphate reduction at 30 °C and initial pH of 7.0. Using the CBP as SRED, sulphate reduction was carried out at different rates: filter paper 0.065-0.050 > potato 0.022-0.034 > crab shell 0.006-0.009 mg SO42-.mg VSS-1d-1. These were also affected by the hydrolysis-fermentation rates: potato 0.087-0.070 > filter paper 0.039-0.047 > crab shell 0.011-0.028 mg CODS.mg VSS-1d-1, respectively. Additionally, the sulphate removal efficiencies using filter paper (cellulose, > 98%), potato (starch, > 82%) and crab shell (chitin, > 32%) were achieved only when using CBP as SRED and in the absence of other easily available electron donors. This study showed that the natural characteristics of the CBP limited the hydrolysis-fermentation step and, therefore, the sulphate reduction rates.

Phosphatidylethanol in Postmortem Brain and Serum Ethanol at Time of Death.

BACKGROUND: Phosphatidylethanol (PEth) is a metabolite of ethanol (EtOH), and its concentration in whole blood samples is a direct biomarker of alcohol consumption. Because PEth is also present in the brain and incorporated in lipid membranes, it can be used to classify deceased individuals on alcohol consumption status at the time of death. The purpose of this study was to detect PEth homologs in postmortem brains of individuals known to have had alcohol use disorder (AUD) and to determine the relationship between serum alcohol at the time of death and PEth in the cerebellum (CE) and orbital frontal cortex (OFC). METHODS: Postmortem brain was collected and stored according to standard protocol. Psychiatric symptoms experienced prior to death were obtained by next of kin psychological autopsy to categorize subjects. Thirty male subjects were chosen for analyses: 10 with AUD with positive serum EtOH levels present at time of autopsy (AUD-W), 10 with AUD without positive serum EtOH levels (AUD-WO), and 10 controls. PEth 16:0/18:1 and 16:0/18:2 were quantified in 50 mg of CE and OFC of human postmortem brain using HPLC and mass spectrometric detection (triple quadrupole). RESULTS: Results of this study were as follows: (i) PEth 16:0/18:1 and 16:0/18:2 were detected in the CE and OFC of all subjects diagnosed with AUD, (ii) PEth 16:0/18:1 levels were about 10-fold higher than PEth 16:0/18:2 in all subjects and both areas of brain, (iii) AUD-W subjects had higher PEth homolog levels in CE and OFC than controls and AUD-WO subjects, (iv) PEth 16:0/18:1, but not PEth 16:0/18:2, levels in CE and OFC of AUD-W subjects correlated significantly with serum EtOH levels at the time of death. CONCLUSIONS: Quantification of combined PEth homolog levels in postmortem human brain is a good candidate as a diagnostic factor to classify drinking status, especially for those with AUD at the time of death. For alcohol research studies with postmortem brain, verification of drinking status is essential.

[(CAG)n polymorphism of the ATXN2 gene, a new marker of susceptibility for type 2 diabetes mellitus]. / El polimorfismo (CAG)n del gen ATXN2, nuevo marcador de susceptibilidad para diabetes mellitus tipo 2.

OBJECTIVE: Estimate whether there is an association between the (CAG)n repeat in the ATXN2 gene in the Mexican population and type 2 diabetes mellitus (DM). METHODS: Epidemiological case-control study, including healthy people and diabetics. (CAG)n expansion was detected by end-point polymerase chain reaction (PCR). PCR outputs were analyzed by electrophoresis (PAGE 8%) and silver nitrate staining. RESULTS: (CAG)n nucleotide allele distribution in the study population was similar to that reported in central Mexico. The 22-repeat allele is the most frequent; however, there is an association with carriers of long repeats in the normal range with diabetes. CONCLUSIONS: The results suggest that the (CAG)n repeat of the ATXN2 gene could be a causal factor for type 2 DM.