Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix.

Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the 'drop-cast' method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young's modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young's modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM.

Increase in Mexican and Latin American scientific articles on irritable bowel syndrome.

BACKGROUND: There is an implied perception that little scientific information on irritable bowel syndrome (IBS) comes out of Mexico and Latin America in the international medical literature, but the number and tendencies of articles from the region on IBS are not known. AIMS: To determine the number and type of Mexican and Latin American articles on IBS published between 1990-2015. METHODS: A systematic search of Medline was carried out employing the terms « Irritable Bowel Syndrome ¼ or its abbreviation (IBS). Mexico and every other Latin American country were added to specify the search. The articles were selected if they were published in Mexico and/or the rest of Latin America, if they were international papers on IBS in the region, or if they were written by Mexican and/or Latin American authors. In addition, the articles were classified into the following categories: Reviews/Editorials/Letters to the Editor (REV/ED), Epidemiology/Quality of Life/Psychosocial Factors (EPI/QOL), Diagnostic (DX), Treatment (TX), and Translational/Pathophysiologic (TRANS) studies. RESULTS: A total of 66 articles from Mexico and 47 from Latin America were identified, but only 87.7 and 48.9%, respectively, fit the selection criteria. Category distribution was: EPI/QOL: 36.2%, REV/ED: 27.5%, TRANS: 18.8, TX: 10%, and DX: 7.5% and was similar between Mexico and Latin America (p=0.33). The year 2005 saw an increase in the number of articles in Mexico, with a peak in 2010. The figures for Latin American articles remained stable over the years, with a peak in 2012. CONCLUSIONS: A noticeable increase has been observed over the last decade in the research conducted on IBS in Mexico and Latin America. Even though the EPI/QOL studies predominate, the sophistication of research is reflected in the TRANS studies that are in third place of frequency. The information referred to herein demonstrates maturity in the field, making it possible to carry out consensuses based on local data.

The role of spreading depolarization in subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a devastating disease associated with death and poor functional outcome. Despite decades of intense research and improvements in clinical management, delayed cerebral ischaemia (DCI) remains the most important cause of morbidity and mortality after SAH. The key role of angiographic cerebral vasospasm, thought to be the main cause of DCI, has been questioned. Emerging evidence suggests that DCI is likely to have a multifactorial etiology. Over the last few years, spreading depolarization (SD) has been identified as a potential pathophysiological mechanism contributing to DCI. The presence of cortical spreading ischaemia, due to an inverse hemodynamic response to SD, offers a possible explanation for DCI and requires more intensive research. Understanding the role of SD as another mechanism inducing DCI and its relationship with other pathological factors could instigate the development of new approaches to the diagnosis and treatment of DCI in order to improve the clinical outcome.

Neuronal Ceroid Lipofuscinosis Type 6 (CLN6) clinical findings and molecular diagnosis: Costa Rica's experience.

BACKGROUND: Commonly known as Batten disease, the neuronal ceroid lipofuscinoses (NCLs) are a genetically heterogeneous group of rare pediatric lysosomal storage disorders characterized by the intracellular accumulation of autofluorescent material (known as lipofuscin), progressive neurodegeneration, and neurological symptoms. In 2002, a disease-causing NCL mutation in the CLN6 gene was identified (c.214G > T) in the Costa Rican population, but the frequency of this mutation among local Batten disease patients remains incompletely characterized, as do clinical and demographic attributes for this rare patient population. OBJECTIVE: To describe the main sociodemographic and clinical characteristics of patients with a clinical diagnosis for Batten Disease treated at the National Children's Hospital in Costa Rica and to characterize via molecular testing their causative mutations. METHODS: DNA extracted from buccal swabs was used for CLN6 gene sequencing. Participants' sociodemographic and clinical characteristics were also obtained from their medical records. RESULTS: Nine patients with a clinical diagnosis of Batten disease were identified. Genetic sequencing determined the presence of the previously described Costa Rican homozygous mutation in 8 of 9 cases. One patient did not have mutations in the CLN6 gene. In all cases where the Costa Rican CLN6 mutation was present, it was accompanied by a substitution in intron 2. Patients were born in 4 of the 7 Costa Rican provinces, with an average onset of symptoms close to 4 years of age. No parental consanguinity was present in pedigrees. Initial clinical manifestations varied between patients but generally included: gait disturbances, language problems, visual impairment, seizures and psychomotor regression. Cortical and cerebellar atrophy was a constant finding when neuroimaging was performed. Seizure medication was a common element of treatment regimens. CONCLUSIONS: This investigation supports that the previously characterized c.214G > T mutation is the most common causative NCL mutation in the Costa Rican population. This mutation is geographically widespread among Costa Rican NCL patients and yields a clinical presentation similar to that observed for CLN6 NCL patients in other geographies.

Synthetic iron (hydr)oxide-glucose associations in subsurface soil: Effects on decomposability of mineral associated carbon.

Soils are a globally important reservoir of organic carbon. There is a growing understanding that interactions with soil mineral phases contribute to the accumulation and retention of otherwise degradable organic matter (OM) in soils and sediments. However, the bioavailability of organic compounds in mineral-organic-associations (MOAs), especially under varying environmental conditions is not well known. To assess the impact of mineral association and warming on the decomposition of an easily respirable organic substrate (glucose), we conducted a series of laboratory incubations at different temperatures with field-collected soils from 10 to 20cm, 50-60cm, and 80-90cm depth. We added 13C-labeled glucose either directly to native soil or sorbed to one of two synthetic iron (hydr)oxide phases (goethite and ferrihydrite) that differ in crystallinity and affinity for sorbing glucose. We found that: (1) association with the Fe (hydr)oxide minerals reduced the decomposition rate of glucose by >99.5% relative to rate of decomposition for free glucose in soil; (2) the respiration rate per gram carbon did not differ appreciably with depth, suggesting a similar degree of decomposability for native C across depths and that under the incubation conditions total carbon availability represents the principal limitation on respiration under these conditions as opposed to reduced abundance of decomposers or moisture and oxygen limitations; (3) addition of free glucose enhanced native carbon respiration at all soil depths with the largest effect at 50-60cm; (4) in general respiration of the organo-mineral complex (glucose and iron-(hydr)oxide) was less temperature sensitive than was respiration of native carbon; (5) the addition of organic free mineral decreased the rate of soil respiration in the intermediate 50-60cm depth soil. The results emphasize the key role of MOAs in regulating the fluxes of carbon from soils to the atmosphere and in turn the stocks of soil carbon.

Response to Comment on "The whole-soil carbon flux in response to warming".

Temperature records and model predictions demonstrate that deep soils warm at the same rate as surface soils, contrary to Xiao et al's assertions. In response to Xiao et al's critique of our Q10 analysis, we present the results with all data points included, which show Q10 values of >2 throughout the soil profile, indicating that all soil depths responded to warming.

Idiopathic macular telangiectasia type 2: Prevalence and a morphometric and phenotypic study. / Telangiectasias maculares idiopáticas de tipo 2: prevalencia en nuestra área y estudio morfométrico y fenotípico.

OBJECTIVE: Type 2 idiopathic macular telangiectasia (MacTel2) is a rare retinal disease that has still not been well-defined. The aim of the present manuscript is to describe the clinical features by multimodal retinal imaging, to present the functional characteristics, and to estimate the prevalence of the disease. METHODS: A retrospective study was conducted on the 12 eyes of 6 patients with MacTel2. Fundus colour photographs, fundus autofluorescence, fluorescein angiography, optical coherence tomography (OCT), and OCT-angiography were performed and subsequently analysed. Visual acuity (VA) was prospectively recorded. The prevalence was established based on the patients referred to a specialised macular diseases unit. Minimum follow-up period was 18 months. RESULTS: Prevalence of MacTel 2 in our study was 0.12%. Clinical features were presented using multimodal retinal imaging. VA remained stable during follow-up. Three patients developed choroidal neovascularisation (CNV), requiring intravitreal treatment with antiangiogenic agents. CONCLUSIONS: The prevalence of the disease found was 0.12%. The study using multimodal imaging allows a more accurate diagnosis and follow-up of this pathology. The VA is maintained during the 18-month follow-up (P=.492). Patients who develop CNV and are treated with antiangiogenic agents appear to respond adequately to them. More studies are needed to establish these conclusions.

The whole-soil carbon flux in response to warming.

Soil organic carbon harbors three times as much carbon as Earth's atmosphere, and its decomposition is a potentially large climate change feedback and major source of uncertainty in climate projections. The response of whole-soil profiles to warming has not been tested in situ. In a deep warming experiment in mineral soil, we found that CO2 production from all soil depths increased with 4°C warming; annual soil respiration increased by 34 to 37%. All depths responded to warming with similar temperature sensitivities, driven by decomposition of decadal-aged carbon. Whole-soil warming reveals a larger soil respiration response than many in situ experiments (most of which only warm the surface soil) and models.

[Neurologic manifestations of infective endocarditis: a diagnostic and prognostic challenge]. / Manifestaciones neurológicas de la endocarditis infecciosa: un reto diagnóstico y pronóstico.

INTRODUCTION: Infective endocarditis (IE) is an ongoing challenge in terms of excess morbidity and mortality. Neurologic complications occur in 20-40% of patients, and the brain is the main location of IE extracardiac complications. AIM: To analyse clinical characteristics of the neurologic complications found in patients with IE, focused on the diagnostic and prognostic aspects. PATIENTS AND METHODS: We studied retrospectively the cases of patients with IE admitted to the Hospital de Valme and Hospital de la Merced between 1998 and 2003. Laterly, patients with and without neurologic manifestations were compared. Sixty episodes of IE were evaluated. RESULTS: Neurological complications occurred in 12 patients (20%). The most frequent neurologic manifestation was unilateral hemi paresis, which occurred in seven cases (58.3%), three cases with acute confusional state (25%) and two patients developed meningitis (16.6%). Brain infarction was the most common lesion found in neuroimaging, in 6 patients (50%), followed by 2 cases (16.6%) of brain hemorrhage, and without significant findings in the cases left. Cases with neurologic complications had significantly higher mortality (p < 0.001) and higher frequency of negative blood culture (p < 0.001). CONCLUSIONS: Neurologic complications of IE are frequent during the evolution of the disease, and they still constitute a significant problem in clinical practice because they often are not accurately diagnosed and significantly increase patients' mortality.

[HLA-DRB1 typing in Caucasians patients with neuromyelitis optica]. / HLA-DRB1 en pacientes caucasicos con neuromielitis optica.

INTRODUCTION: The existence of antibodies to aquaporin-4 (AQP-4-ab) has identified neuromyelitis optica (NMO) and multiple sclerosis (MS) as different diseases. Although HLA-DRB1 alleles contribute to MS risk, recent studies suggest that HLA back-ground differs between patients with NMO or MS in non-Caucasians populations. Our study was aimed to analyze HLA-DRB1 distribution in Caucasians NMO patients. SUBJECTS AND METHODS: We recruited a cohort of 22 NMO patients (73% were AQP-4-ab positive), 228 MS patients and 225 healthy controls from Spain and we genotyped the HLA-DRB1 locus. Then, we performed a pool analysis using reported data from 45 NMO patients (53% were AQP-4-ab positive), 156 MS patients and 310 healthy controls from Caucasian French population. RESULTS: In the Spanish cohort, NMO was associated with increased frequency of DRB1*10 allele compared with MS (odds ratio, OR = 15.1; 95% confidence interval, 95% CI = 3.26-69.84; p = 0.012). In the pooled analysis, by comparison with healthy controls, NMO was associated with increased frequency of DRB1*03 allele (OR = 2.27; 95% CI = 1.44-3.58; p < 0.0008) which was related to AQP-4-ab seropositivity (OR = 2.74; 95% CI = 1.58-4.77; p < 0.0008). By contrast, MS was associated with increased frequency of DRB1*15 allele (OR = 2.09; 95% CI = 1.62-2.68; p < 0.0008) and decreased frequency of DRB1*07 allele (OR = 0.58; 95% CI = 0.44-0.78; p < 0.0008). CONCLUSIONS: Caucasian patients with NMO and MS have a different HLA-DRB1 allelic distribution. DRB1*03 allele seems to contribute to NMO seropositivity. Multicenter collaborative efforts are needed to adequately address the genetic contribution to NMO susceptibility.

[Hyperammonaemic encephalopathy due to valproic acid]. / Encefalopatía hiperamoniémica por ácido valproico.

INTRODUCTION: One of the less frequent idiosyncratic side effects of valproic acid (VPA) is encephalopathy. Here we report one case. CASE REPORT: An 83-year-old female with no relevant past history, who received treatment with VPA following a post-traumatic subarachnoid haemorrhage and two convulsive seizures. A few days later, she was admitted to the Emergency Department because of a progressive clinical picture of mental slowness, nauseas and apathy. The systemic examination was normal. Neurologically, the most striking features were inattention and disorientation, despite her having a good level of consciousness, and mental confusion. Levels of VPA were within the below-therapeutic range and the basic lab findings (including hepatic profile) were normal, except for hyperammonaemia. Neuroimaging studies and cerebrospinal fluid analysis were also normal. An electroencephalogram (EEG) showed signs of severe diffuse encephalopathy with slow, triphasic waves and a non-convulsive epileptic status was therefore ruled out. After withdrawing the VPA, the patient's condition improved until her basal situation was reached in 48 hours and the EEG became normal, as did her ammonium levels. CONCLUSION: When faced with a patient who has recently been taking VPA and who presents a clinical picture of mental confusion, the possibility of encephalopathy due to said drug must be taken into consideration.

Molecular analysis of an NAD-dependent alcohol dehydrogenase from the zygomycete Mucor circinelloides.

NAD-dependent alcohol dehydrogenase (ADH) activity was detected mainly in the cytosol of aerobically cultured mycelium and in anaerobically grown yeast cells of Mucor circinelloides. ADH levels were about 2.5-fold higher in yeast cells than in mycelium; zymogram analysis suggested that the same ADH enzyme is produced in both developmental stages. The enzyme, named ADH1, was purified to homogeneity from yeast cells, using ion-exchange and affinity chromatography. The active ADH1 appears to be a homomeric tetramer of 37,500-kDa subunits. Km values obtained for acetaldehyde, ethanol, NADH and NAD+ indicated that in vivo the enzyme mainly serves to reduce acetaldehyde to ethanol. Amino acid sequences of internal peptides obtained from the purified ADH1 were used to design oligonucleotides that allowed the cloning of the corresponding cDNA by RT-PCR, and the characterization of the genomic DNA sequence. The adh1 ORF is interrupted by two small introns located towards the 5'-end. M. circinelloides adh1 encodes a protein of 348 amino acids, which display moderate to high overall identity to several hypothetical ADH enzymes from the related zygomycete Rhizopus oryzae. adh1 mRNA is expressed at similar levels in aerobic mycelium and anaerobic yeast cells. During exponential growth under aerobic conditions, the level of adh1 transcript was correlated with the glucose concentration in the growth medium.

Cleistogamous capitulum in Centaurea melitensis (Asteraceae): heterochronic origin.

Cleistogamous capitula formed by Centaurea melitensis display a number of morphological and functional changes with respect to chasmogamous capitula that ensure self-fertilization. Because no studies have hitherto addressed the evolution of cleistogamy in Asteraceae, it was considered useful to ascertain whether these changes are attributable to one or more of the heterochronic processes reported in the literature. Bivariate allometric analyses were performed, and changes were represented graphically using Gould's clock models for size, shape, and age of several capitulum and floret structures. Results suggest that the partially paedomorphic appearance of cleistogamous with respect to chasmogamous capitula is attributable to three processes: (1) early onset of floral development (predisplacement), (2) decreased growth rate of the whorls studied (except gynoecium width) and (3) early offset time (progenesis). The latter appears to play the most significant role in the origin of the cleistogamous capitulum.