Resistive switching control for conductive Si-nanocrystals embedded in Si/SiO2 multilayers.

In this paper, we report on the enhanced control of resistive switching in multilayer Si/SiO2 structures, which permit the formation of Si nanocrystals with a typical size of 5.88 nm and overall good shape homogeneity. The deposition of a different number of Si and SiO2 bilayers (6, 8 and 10) allowed control of SET/RESET voltages in negative bias ranges 4.5-10 V and 6.3-13 V for six- and ten-bilayer devices, respectively. The corresponding resistance ratio between ON/OFF states varied in the ranges 107-105 for the aforementioned number of bilayers. Based on the result of XPS measurements, we suggest that the resistive switching in the studied system occurs due to the formation and annihilation of Si-Si and Si-O bonds, which serve as conductive pathways and isolating material, respectively.

Association between -174G/C and -572G/C interleukin 6 gene polymorphisms and severe radiographic damage to the hands of Mexican patients with rheumatoid arthritis: a preliminary report.

Several interleukin 6 gene (IL6) polymorphisms are implicated in susceptibility to rheumatoid arthritis (RA). It has not yet been established with certainty if these polymorphisms are associated with the severe radiographic damage observed in some RA patients, particularly those with the development of joint bone ankylosis (JBA). The objective of the present study was to evaluate the association between severe radiographic damage in hands and the -174G/C and -572G/C IL6 polymorphisms in Mexican Mestizo people with RA. Mestizo adults with RA and long disease duration (>5 years) were classified into two groups according to the radiographic damage in their hands: a) severe radiographic damage (JBA and/or joint bone subluxations) and b) mild or moderate radiographic damage. We compared the differences in genotype and allele frequencies of -174G/C and -572G/C IL6 polymorphisms (genotyped using polymerase chain reaction-restriction fragment length polymorphism) between these two groups. Our findings indicated that the -174G/C polymorphism of IL6 is associated with severe joint radiographic damage [maximum likelihood odds ratios (MLE_OR): 8.03; 95%CI 1.22-187.06; P = 0.03], whereas the -572G/C polymorphism of IL6 exhibited no such association (MLE_OR: 1.5; 95%CI 0.52-4.5; P = 0.44). Higher anti-cyclic citrullinated peptide antibody levels were associated with more severe joint radiographic damage (P = 0.04). We conclude that there is a relevant association between the -174G/C IL6 polymorphism and severe radiographic damage. Future studies in other populations are required to confirm our findings.

Endoscopic transchoroidal and transforaminal approaches for resection of third ventricular colloid cysts.

To review our experience over 10 years in endoscopic resection of third ventricular colloid cysts, describing the details of the transventricular-transchoroidal approach used in selected patients. This series included 24 patients with colloid cysts of the third ventricle treated in our department between October 2001 and January 2013 using an endoscopic approach. Clinical presentation, preoperative radiological findings, endoscopic technique employed, and complications were assessed in all patients. The mean length of patient follow-up was 5.16 years. The most common symptom was headache (75%). The average size of the resected colloid cysts was 16.25 mm, the maximum diameter measured in cranial magnetic resonance imaging. Resection was transforaminal in 16 cases (66.7%), transchoroidal in 7 (29.17%), and transseptal in 1; macroscopically complete resection was achieved in 23 of 24 procedures (95.8%). Complications included three intraventricular hemorrhages, four memory deficits (two of them transient), one case of temporary potomania, two soft tissue infections, and one meningitis. There were no statistically significant differences between the route of resection and number of complications. The Glasgow Outcome Scale at 1 year after surgery was 5 in 82.6% of the patients. A transventricular endoscopic approach allows macroscopically complete resection of third ventricle colloid cysts in most cases. The option of opening the choroidal fissure (transventricular-transchoroidal approach) during the procedure can address third ventricle colloid cysts that do not emerge sufficiently through the foramen of Monro without increasing procedure-related morbidity.

The -174G/C and -572G/C interleukin 6 promoter gene polymorphisms in mexican patients with rheumatoid arthritis: a case-control study.

OBJECTIVE: There is a lack of information about the genotype frequencies of IL-6 -174G/C and -572G/C polymorphisms in Mexicans with rheumatoid arthritis (RA). Therefore, the aim of this study was to evaluate the association of the IL-6 -174G/C and -572G/C polymorphisms in Mexican mestizo with RA. METHODS: We included 137 patients with RA and 102 healthy controls. Patients were assessed for clinical characteristics. IL-6 -174G/C and -572G/C polymorphisms were genotyped using PCR-RFLP analysis. Allele and genotype frequencies and the Hardy-Weinberg equilibrium were computed. Odds ratios (ORs) were computed to identify the risk for RA associated with the presence of GG genotype in comparison with the GC or CC genotypes. RESULTS: The genotype -174GG occurred at a higher frequency in cases and controls (77.4% versus 78.4%, P = 0.845). We found similar results for the genotype -572GG (54% in patients versus 60.8% in controls, P = 0.295). CONCLUSIONS: This is the first study to evaluate the association of -174G/C and -572G/C polymorphisms of the IL-6 gene with RA in Mexican mestizo patients. These two polymorphisms were not associated with RA in the studied sample. Additional studies are required to evaluate if these IL-6 polymorphisms have relevance to the development of more severe disease.

Prescription for antiresorptive therapy in Mexican patients with rheumatoid arthritis: is it time to reevaluate the strategies for osteoporosis prevention?

Glucocorticoids are frequently used in rheumatoid arthritis (RA) in order to alleviate symptoms of joint inflammation, retard erosions and to treat extra-articular manifestations, although these drugs may increase the risk of bone mineral loss and osteoporotic fractures. To date, in Mexico there are no studies that identify the frequency of patients with RA with corticosteroids, receiving therapy for osteoporosis. Therefore, we evaluated the prevalence and factors related to the prescription of antiresorptives in 520 Mexican patients with RA. We used a multivariate model to identify variables associated with antiresorptives prescription. We identified that although 79% of patients were under treatment with glucocorticoids, only 13% received antiresorptive agents as preventive therapy for osteoporosis. The multivariate analysis identified that higher proportions of antiresorptive drugs prescriptions were associated with female patients (OR 11.40, 95% CI: 1.5-84.3, P = 0.02), an age of 40 years or more (OR 3.22, 95% CI: 1.3-8.3, P = 0.02) and to consume a lower number of cointerventions with other drugs (OR 1.09, 95% CI: 1.0-1.2, P = 0.03). Corticosteroid treatment was not associated with the prescription of antiresorptives (P = 0.31). In conclusion, a low proportion of Mexicans with RA receive antiresorptive therapy independently regardless of whether they consume or not chronically corticosteroids. Additional strategies should be evaluated to encourage the prevention and early treatment for osteoporosis in patients with RA.

The ACTN3 R577X polymorphism is associated with inflammatory myopathies in a Mexican population.

BACKGROUND: The ACTN3 gene encodes the fast muscle protein α-actinin-3. The ACTN3 R577X polymorphism is a premature stop codon and results in absence of α-actinin-3 in 577XX homozygotes. The aim of this study was to determine the ACTN3 genotype in idiopathic inflammatory myopathies (IIMs). METHODS: We performed ACTN3 genotyping on 27 patients with dermatomyositis (DM), 10 with polymyositis (PM), and 85 healthy subjects. Muscle enzyme levels of creatine phosphokinase (CPK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were recorded at the time of diagnosis and recruitment. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and the allele frequency was analysed. RESULTS: A total of 36% of healthy subjects had the ACTN3 577XX polymorphism (α-actinin-3 deficiency), 18% had the 577RR (homozygous wild type) genotype, and 46% 577RX (heterozygous). In DM/PM, 70% had the ACTN3 577XX polymorphism, 6% RR, and 24% RX [odds ratio (OR) 4.12, 95% confidence interval (CI) 1.67-10.33, p < 0.001]. In healthy subjects, the R allele was present in 41% and the X allele in 59% compared to 18% and 82%, respectively, in the IIM group (OR 3.21, 95% CI 1.57-6.66, p < 0.001). Thus, the ACTN3 577X allele seemed to increase the risk of developing IIM, and DM in particular, although this was not related to severity of expression of the phenotype. CONCLUSIONS: The ACTN3 577X allele appeared to increase the risk of developing IIM; 70% of IIM patients were deficient in α-actinin-3. By contrast, ACTN3 577XX patients seemed to have less severe disease as reflected in lower muscle enzyme levels.

Hepatitis A virus genetic diversity in Venezuela: exclusive circulation of subgenotype IA and evidence of quasispecies distribution in the isolates.

Hepatitis A virus (HAV) infection is highly prevalent in Latin America, including Venezuela. Subgenotype IA seems to circulate in an almost exclusive fashion, except in Brazil. The aim of this study was the molecular characterization of the HAV infection in Venezuela, in order to characterize the circulating strains and to analyze the presence of quasispecies in sporadic cases and an epidemic outbreak. A total of 125 (113 sera and 12 feces) samples positive for anti-HAV IgM from sporadic cases and epidemic outbreak, were submitted to hemi-nested RT-PCR for amplification of the VP1 N terminus or complete region of the HAV genome. Sequences obtained from 96 Venezuelan isolates were used for phylogenetic analysis. The quasispecies distribution was evaluated by cloning of HAV amplicons. Phylogenetic analysis of HAV sequences from Venezuela showed the exclusive circulation of subgenotype IA, but with co-circulation of two lineages, not found in other countries. The genetic variability found among Venezuelan strains was also analyzed by single-strand conformation polymorphism (SSCP). This technique allowed the detection of intra-strain variability, which was indeed related to the presence of quasispecies populations in the isolates. The quasispecies heterogeneity was higher in some isolates derived from sporadic cases compared to the one observed in the outbreak. The molecular characterization of HAV isolates from Venezuela showed the circulation of a unique subgenotype IA, but with the presence of diverse strains and quasispecies inside the viral populations.

Autoantibodies to a miRNA-binding protein Argonaute2 (Su antigen) in patients with hepatitis C virus infection.

OBJECTIVES: Chronic liver diseases caused by hepatitis B (HBV) or C virus (HCV) are common worldwide. Despite reports on autoimmunity in viral hepatitis, studies on autoantibodies associated with systemic rheumatic diseases are inconsistent. Testing of a small number of selected autoantibody specificities using ELISA appears to be one reason for inconsistency. Sera from patients with viral hepatitis were tested by immunoprecipitation that will allow unbiased screening of autoantibodies found in systemic rheumatic diseases. METHODS: Ninety Mexican patients (37 male, 53 female, 26 HBV, 6 HBV+HCV, 58 HCV) with chronic viral hepatitis, confirmed by nested or RT-nested-PCR, HBsAg and anti-HCV antibodies, were studied. Autoantibodies were tested by immunofluorescence, immunoprecipitation and ELISA. Specificities were verified using reference sera. RESULTS: Antinuclear antibodies were found in 38% HBV, 17% HBV+HCV, and 28% in HCV. Autoantibodies to Argonaute (Ago2, Su antigen), a microRNA binding protein that plays a key role in RNA-induced silencing complex (RISC), was found in 5% (4/64) of HCV or HBV+HCV coinfected patients but not in HBV (0/26). Anti-Ago2/Su was found in 1/2 of I-IFN-treated case vs. 3/62 in cases without I-IFN. HCV did not have other lupus autoantibodies whereas 19% (5/26) of HBV had anti-U1RNP+Ku, Ro+La, RNA polymerase II, or possible U5snRNPs. CONCLUSIONS: Lupus autoantibodies were uncommon in HCV except anti-Ago2/Su. HCV and I-IFN have many ways to affect TLR signaling, miRNA and miRNA binding protein Ago2/Su. To understand the mechanism of specific targeting of Ago2 in HCV may provide a clue to understand the mechanism of specific autoantibody production.

[Ventricular haemorrhage in preterm neonates and posthemorrhagic hydrocephalus. Proposal of a management protocol based on early ventriculo-peritoneal shunt]. / Hemorragia intraventricular del prematuro e hidrocefalia post-hemorrágica.Propuesta de un protocolo de manejo basado en la derivación ventrículo-peritonealprecoz.

INTRODUCTION: About 50% of the preterm neonates with a ventricular haemorrhage will develop posthaemorrhagic hydrocephalus. Medical treatment is not effective neither safe, does not reduce shunt's dependence and therefore can not be recommended; early and repetitive ventricular or lumbar punctures and the use of intraventricular fibrynolitic treatment have showed no effect on reducing patient's disability, shunt's necessity or mortality of these patients and furthermore, they can have several and important side effects. The ventriculo-peritoneal shunt can be in many cases the only option for definitive treatment, despite well-known infective and obstructive complications and there is an ongoing debate about the ideal moment for the intervention. OBJECTIVE: To present a diagnostic and treatment protocol for post-haemorrhagic hydrocephalus of the preterm and describe our initial experience with its application on the Paediatric Neurosurgical Department at the Hospital Materno-Infantil Carlos Haya of Málaga. MATERIALS AND METHODS: A total of 21 patients with diagnosis of preterm post-haemorrhagic hydrocephalus were surgically treated at our hospital with ventriculoperitoneal shunt between January 2003 and September 2006 following the designed protocol. All the cases were Papile's grade III or IV with severe ventricular dilation (Thalamus-Caudate index over 1.5 cm) and subacute or chronic presentation. We used medium pressure valves and antibiotic impregnated catheters. We considered 1500 g as the minimum weight permitted for the intervention. We report the early and late postoperative complications and the patients functional state at the ambulatory follow up classifying them in 4 grades (Excellent or Grade 1; Good or Grade 2; Regular or Grade 3; Poor or Grade 4) according to the presence of neurological focal signs, relation with the surrounding environment, response to stimuli and presence of seizures. RESULTS: The most frequent complications were escaphocephalic cranium in 5 patients, persistent subgaleal collections in 2 patients, symptomatic slit ventricles in 2 patients and surgical wound dehiscence with shunt infection in 1 patient. One patient presented a systemic fungical infection with non-diagnosed meningeal compromise previous to the shunt. 7 patients required shunt replacement (14 procedures); in 2 cases of tabicated hydrocephalus an endoscopical septostomy (associated with an ETV that did not function) was done, and in a third case ETV and shunt removal was performed after shunt malfunction, with delayed failure of ETV. For the functional results 9 patients were classified as Grade 1, 5 patients as Grade 2, 3 patients as Grade 3 and 4 patients as Grade 4. This means a 67% of good or excellent results. CONCLUSIONS: We propose a diagnostic and treatment protocol for preterm neonates with haemorrhagic hydrocephalus that we have been using since 2003 at our department. In our experience it is possible to shunt patients starting at 1500 g with low morbidity. The use of protocols can help in reducing complications and improving functional results in these patients.

[Elbow dislocation]. / Luxación de codo.

Elbow dislocation is the most frequent dislocation in the upper limb after shoulder dislocation. Closed reduction is feasible in outpatient care when there is no associated fracture. A review is presented of the different reduction procedures.

Polymorphism rs2073618 of the TNFRSF11B (OPG) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis.

Osteoporosis (OP) is highly prevalent in rheumatoid arthritis (RA) and is influenced by genetic factors. Single-nucleotide polymorphism (SNP) rs2073618 in the TNFRSF11B osteoprotegerin (OPG) gene has been related to postmenopausal OP although, to date, no information has been described concerning whether this polymorphism is implied in abnormalities of bone mineral density (BMD) in RA. We evaluated, in a case-control study performed in Mexican-Mestizo women with RA, whether SNP rs2073618 in the TNFRSF11B gene is associated with a decrease in BMD. RA patients were classified as follows: (1) low BMD and (2) normal BMD. All patients were genotyped for the rs2073618 polymorphism by PCR-RFLP. The frequency of low BMD was 74.4%. Higher age was observed in RA with low BMD versus normal BMD (62 and 54 years, resp.; p < 0.001). Worse functioning and lower BMI were observed in RA with low BMD (p = 0.003 and p = 0.002, resp.). We found similar genotype frequencies in RA with low BMD versus RA with normal BMD (GG genotype 71% versus 64.4%, GC 26% versus 33%, and CC 3% versus 2.2%, resp.; p = 0.6). We concluded that in Mexican-Mestizo female patients with RA, the rs2073618 polymorphism of the TNRFS11B gene is not associated with low BMD.

Molecular mechanisms in normal pregnancy and rheumatic diseases.

Pregnancy is a phenomenon that is not totally understood, based on the complex molecular interactions between the mother and the embrio. Once the fecundation is completed the fetus starts to fight for survival. The first challenge is the implantation process and the second one is the interaction with the maternal immune system. This review discusses how the fetus avoids the immune system rejection, and the mechanisms that the maternal immune system adapts in order to be fit for a successful pregnancy. Also, we focus in this paper on the effects of pregnancy in rheumatic diseases, because the myriad clinical outcomes of the disease itself and the obstetric complications dependent of the disease implicated, as for example in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropaties and antiphospholipid syndrome (APS).

The -174G/C Interleukin-6 Gene Promoter Polymorphism as a Genetic Marker of Differences in Therapeutic Response to Methotrexate and Leflunomide in Rheumatoid Arthritis.

Objective. To evaluate the association of -174G/C IL-6 polymorphism with failure in therapeutic response to methotrexate (MTX) or leflunomide (LEF). This prospective, observational cohort included 96 Mexican-Mestizo patients with moderate or severe rheumatoid arthritis (RA), initiating MTX or LEF, genotyped for IL-6 -174G/C polymorphism by PCR-RFLP. Therapeutic response was strictly defined: only if patients achieved remission or low disease activity (DAS-28 < 3.2). Results. Patients with MTX or LEF had significant decrement in DAS-28 (p < 0.001); nevertheless, only 14% and 12.5% achieved DAS-28 < 3.2 at 3 and 6 months. After 6 months with any of these drugs the -174G/G genotype carriers (56%) had higher risk of therapeutic failure compared with GC (RR: 1.19, 95% CI: 1.07-1.56). By analyzing each drug separately, after 6 months with LEF, GG genotype confers higher risk of therapeutic failure than GC (RR = 1.56; 95% CI = 1.05-2.3; p = 0.003), or CC (RR = 1.83; 95% CI = 1.07-3.14; p = 0.001). This risk was also observed in the dominant model (RR = 1.33; 95% CI = 1.03-1.72; p = 0.02). Instead, in patients receiving MTX no genotype was predictor of therapeutic failure. We concluded that IL-6 -174G/G genotype confers higher risk of failure in therapeutic response to LEF in Mexicans and if confirmed in other populations this can be used as promissory genetic marker to differentiate risk of therapeutic failure to LEF.

Metabolic indices shift in the hypothalamic-neurohypophysial system during lactation: implications for interpreting their relationship with neuronal activity.

Metabolic indices of neuronal activity are thought to predict changes in the frequency of action potentials. There are stimuli that do not shift action potential frequency but change the temporal organization of neuronal firing following modifications of excitatory inputs by inhibitory synaptic activation. To our knowledge it is unknown whether this kind of stimulus associates with adjustments of metabolic markers of neuronal activity. Here, we used the hypothalamic-neurohypophysial system of lactating rats to address whether shifts in the temporal organization of neuronal firing relate with modifications of metabolic markers of neuronal activity. Cytochrome oxidase activity, (3)H-2-deoxyglucose uptake, and the area occupied by blood vessels increased in the paraventricular nucleus and neurohypophysis of lactating rats, as compared with their virgin counterparts. Taken together, these results suggest that metabolic demands denote shifts in the temporal organization of action potentials related with the adjustment of excitatory synaptic activation, and support that changes in metabolic markers do not necessarily reflect shifts in the frequency of action potentials.

Massive myeloid sarcoma affecting the central nervous system, mediastinum, retroperitoneum, liver, and rectum associated with acute myeloblastic leukaemia: a case report.

Myeloid sarcomas are extramedullary tumours with granulocytic precursors. When associated with acute myelogenous leukaemia (AML), these tumours usually affect no more than two different extramedullary regions. This report describes a myeloid sarcoma associated with AML with tumour formation at five anatomical sites. The patient was a 37 year old man admitted in September 1999 with a two month history of weight loss, symptoms of anaemia, rectal bleeding, and left facial nerve palsy. The anatomical sites affected were: the rectum, the right lobe of the liver, the mediastinum, the retroperitoneum, and the central nervous system. A bone marrow smear was compatible with AML M2. Flow cytometry showed that the peripheral blood was positive for CD4, CD11, CD13, CD14, CD33, CD45, and HLA-DR. A karyotypic study of the bone marrow revealed an 8;21 translocation. The presence of multiple solid tumours in AML is a rare event. Enhanced expression of cell adhesion molecules may be the reason why some patients develop myeloid sarcomas.

Síndrome de DRESS / DRESS syndrome

No disponible

Melanocitoma meníngeo del ángulo pontocerebeloso: claves imagenológicas para su abordaje / Cerebellopontine meningeal melanocytoma: keys for imaging diagnostic approach

Resumen: Las lesiones del ángulo pontocerebeloso (APC) representan el 6 al 10% de las neoplasias intracraneales, siendo los schwannomas vestibulares y meningiomas los más comunes. Sin embargo, hasta el 15% pueden ser otras lesiones, entre ellas las derivadas a partir de restos de células melanocíticas presentes en las leptomeninges. El diagnóstico diferencial de las patologías tumorales del APC es extenso, siempre teniendo en cuenta las lesiones más comunes. Sin embargo, cuando las características radiológicas no son las esperadas, el enfoque debe orientarse hacia las lesiones inusuales, poniendo en contexto las diferentes estirpes celulares que pueden dar origen a las neoplasias en esta localización, como las neoplasias melanocíticas. Se presenta el caso de un masculino de 74 años con síndrome cerebeloso de tórpida evolución, al cual se le realiza RM de cerebro contrastada, identificando una lesión de base dural en el APC izquierdo, con hiperintensidad de señal en T1 e hipointensidad en T2, atípico para las lesiones más comunes en esta región, que sugiere su contenido melanocítico.

Abstract: Cerebellopontine angle tumors (CPA) represent approximately 6 to 10% of intracranial tumors. Vestibular Schwannomas and meningiomas are the most common, however up to 15% can be of other origin, including from melanocytes derived from the neural crest. The differential diagnosis of CPA pathologies is extensive, always taking into account the most common ones. However, if the radiological characteristics are not the expected, the approach should be directed towards unusual lesions, putting into context the different cell lines that can give rise to the neoplasm at this location, such as melanotic neoplasms. We present a case of a 74-year-old male, who presented with a cerebellar syndrome. Due to an atypical clinical evolution, a contrast enhanced head MRI was performed, revealing a dural based tumor on the left CPA, which was hyperintense on T1 and hypointense on T2 weighted sequences, which is not expected from the common lesions at this region and suggested it's melanotic content.

Curacin D, an antimitotic agent from the marine cyanobacterium Lyngbya majuscula.

Curacin D is a novel brine shrimp toxic metabolite isolated from a Virgin Islands collection of the marine cyanobacterium Lyngbya majuscula. Structure elucidation of curacin D was accomplished through multidimensional NMR, GC/MS, and comparisons with curacin A. Curacin D provides new insights into structure-activity relationships in this natural product class as well as some aspects of the likely biosynthetic pathway of the curacins.