Ca2+ signaling in postsynaptic neurons: Neuroplastin-65 regulates the interplay between plasma membrane Ca2+ ATPases and ionotropic glutamate receptors.

Upon postsynaptic glutamate receptor activation, the cytosolic Ca2+ concentration rises and initiates signaling and plasticity in spines. The plasma membrane Ca2+ ATPase (PMCA) is a major player to limit the duration of cytosolic Ca2+ signals. It forms complexes with the glycoprotein neuroplastin (Np) isoforms Np55 and Np65 and functionally interplays with N-methyl-D-aspartate (NMDA)-type ionotropic glutamate receptors (iGluNRs). Moreover, binding of the Np65-specific extracellular domain to Ca2+-permeable GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type ionotropic glutamate receptors (iGluA1Rs) was found to be required for long-term potentiation (LTP). However, the link between PMCA and iGluRs function to regulate cytosolic Ca2+ signals remained unclear. Here, we report that Np65 coordinates PMCA and iGluRs' functions to modulate the duration and amplitude of cytosolic Ca2+ transients in dendrites and spines of hippocampal neurons. Using live-cell Ca2+ imaging, acute pharmacological treatments, and GCaMP5G-expressing hippocampal neurons, we discovered that endogenous or Np65-promoted PMCA activity contributes to the restoration of basal Ca2+ levels and that this effect is dependent on iGluR activation. Super-resolution STED and confocal microscopy revealed that electrical stimulation increases the abundance of synaptic neuroplastin-PMCA complexes depending on iGluR activation and that low-rate overexpression of Np65 doubled PMCA levels and decreased cell surface levels of GluN2A and GluA1 in dendrites and Shank2-positive glutamatergic synapses. In neuroplastin-deficient hippocampi, we observed reduced PMCA and unchanged GluN2B levels, while GluN2A and GluA1 levels were imbalanced. Our electrophysiological data from hippocampal slices argues for an essential interplay of PMCA with GluN2A- but not with GluN2B-containing receptors upon induction of synaptic plasticity. Accordingly, we conclude that Np65 may interconnect PMCA with core players of glutamatergic neurotransmission to fine-tune the Ca2+ signal regulation in basal synaptic function and plasticity.

Impact of Whole-Body Perfusion in Postoperative Outcomes After Aortic Arch Reconstruction Surgery in Neonates and Infants.

INTRODUCTION: The aim of this study was to determine whether whole-body perfusion (WBP) consisting of a combined antegrade cerebral perfusion (ACP) and lower body perfusion (LBP) improves the outcome after aortic arch reconstruction surgery in neonates compared with ACP. METHODS: Sixty-five consecutive patients under one year of age who underwent aortic arch reconstruction as the main procedure or as part of a more complex surgery from 2014-2020 in our center were included. The patients were separated into two groups, according to the perfusion strategy, either ACP (34 patients) as the control group or WBP (31 patients) as the intervention group. LBP was achieved through an arterial sheath in the femoral artery. Outcome parameters were postoperative renal, gastrointestinal, and neurological complications and 30-day mortality. RESULTS: The patients in the WBP group showed lower intraoperative lactate levels and close to normal early postoperative renal and hepatic enzymes and LDH at PICU admission compared with the patients in the ACP group. The number of patients suffering from postoperative neurological complications and multiorgan failure was lower in the WBP group. CONCLUSION: In our experience, the combined use of ACP and LBP through the femoral artery showed an improvement, regarding postoperative neurologic complications in neonates and infants undergoing aortic arch surgery.

Performance of pre-transplant criteria in prediction of hepatocellular carcinoma progression and waitlist dropout.

BACKGROUND & AIM: Liver transplantation (LT) selection models for hepatocellular carcinoma (HCC) have not been proposed to predict waitlist dropout because of tumour progression. The aim of this study was to compare the alpha-foetoprotein (AFP) model and other pre-LT models in their prediction of HCC dropout. METHODS: A multicentre cohort study was conducted in 20 Latin American transplant centres, including 994 listed patients for LT with HCC from 2012 to 2018. Longitudinal tumour characteristics, and patterns of progression were recorded at time of listing, after treatments and at last follow-up over the waitlist period. Competing risk regression models were performed, and model's discrimination was compared estimating Harrell's adapted c-statistics. RESULTS: HCC dropout rate was significantly higher in patients beyond (24% [95% CI 16-28]) compared to those within Milan criteria (8% [95% IC 5%-12%]; p < .0001), with a SHR of 3.01 [95% CI 2.03-4.47]), adjusted for waiting list time and bridging therapies (c-index 0.63 [95% CI 0.57; 0.69). HCC dropout rates were higher in patients with AFP scores >2 (adjusted SHR of 3.17 [CI 2.13-4.71]), c-index of 0.71 (95% CI 0.65-0.77; p = .09 vs Milan). Similar discrimination power for HCC dropout was observed between the AFP score and the Metroticket 2.0 model. In patients within Milan, an AFP score >2 points discriminated two populations with a higher risk of HCC dropout (SHR 1.68 [95% CI 1.08-2.61]). CONCLUSIONS: Pre-transplant selection models similarly predicted HCC dropout. However, the AFP model can discriminate a higher risk of dropout among patients within Milan criteria.

Multiple Breath Washout Testing to Identify Pulmonary Chronic Graft Versus Host Disease in Children After Hematopoietic Stem Cell Transplantation.

Pulmonary chronic graft versus host disease (p-cGvHD) is a highly morbid, late complication of hematopoietic stem cell transplantation (HSCT). The 2014 National Institutes of Health cGvHD consensus criteria require a tissue biopsy or a drop in spirometry (with other features) to establish the diagnosis of p-cGvHD. Unfortunately, children are often incapable of performing spirometry, which can delay the diagnosis of this condition. Multiple breath washout testing (MBW) can detect abnormal pulmonary physiology in older children and adults after HSCT, but its feasibility and utility have not been assessed in younger children and in those who cannot perform spirometry. In this study, we assess the feasibility and sensitivity of MBW to detect p-cGvHD in children as young as 3 years of age after HSCT. We performed a cross-sectional analysis of children age 3 to 18 years, between 100 days and 5 years after allogenic HSCT. Participants were recruited from the HSCT population at BC Children's Hospital (Vancouver, Canada). All participants attempted nitrogen MBW, and children age 6 years and over attempted spirometry. Nonparametric statistical techniques were used; descriptive statistics used median (interquartile range [IQR]) and group medians were compared using Wilcoxon rank-sum test. Twenty-six children, median age 11.0 (range 3.6-18.5) years, were recruited a median of 26.4 (IQR 15.7, 51.8) months after HSCT. Six of the 26 children (23%) had a clinical diagnosis of p-cGvHD. MBW was successful in all (26/26, 100%) participants. The lung clearance index (LCI; the primary outcome of MBW) was higher in those with a history of p-cGvHD (median 11.8 [IQR 9.6, 18.7]) than in those with no history of cGvHD (median 7.7 [IQR 7.1, 8.0]; P = .001) or a history of extrapulmonary cGvHD (median 7.5 [IQR 6.9, 7.6], P = .007). A threshold LCI = 9 resulted in a sensitivity of 100% and specificity of 90% for the correct identification of clinically diagnosed p-cGvHD using MBW (area under the receiver operator characteristic curve is 0.97 [95% confidence interval 0.80, 0.99]). Spirometry was successful in most (17/26, 65%) participants. Similar to LCI, forced expiratory volume in 1 second (FEV1)/ forced vital capacity could distinguish between p-cGvHD and no cGvHD (P = .02) and extrapulmonary cGvHD (P = .01). FEV1 alone could not distinguish between either of these groups (P = .87, P = .24 respectively). MBW is feasible in young children after HSCT and in those who cannot perform spirometry. LCI has high discriminative power for correctly identifying p-cGvHD, but these preliminary results require confirmation in a larger validation cohort.

Lesiones del ligamento cruzado anterior en esquiadores: conceptos actuales / Anterior cruciate ligament injuries in skiers: current concepts

El esquí es un deporte individual con una tasa de lesiones de 1,84 por 1.000 días esquiador en la población general. Las roturas del ligamento cruzado anterior (LCA) son algunas de las más comunes, llegando a una tasa de 5 por cada 100 esquiadores por temporada a nivel competitivo, debido a la gran exigencia a la que se encuentran sometidas las rodillas. Lo anterior presenta un desafío para el traumatólogo a la hora de plantear un manejo. Se realizó una revisión de la literatura respecto de los mecanismos de lesión, tratamiento, prevención, rehabilitación y uso de órtesis en el retorno deportivo. Se describen los mecanismos clásicos de lesión en esquiadores amateurs y competitivos. La mayoría de las lesiones de LCA son de resolución quirúrgica, en que la recomendación de reconstrucción debe ser con injerto autólogo de hueso-tendón patelar-hueso, salvo en los pacientes mayores o en pacientes con fisis abierta, en los que se recomienda el uso de injerto autólogo de semitendinoso-gracilis. La prevención y rehabilitación se basan en mejorar la fuerza y el control neuromuscular de los estabilizadores dinámicos de la rodilla implementándose programas específicos, evaluación del gesto deportivo, y pruebas de control neuromuscular. Se recomienda el uso de órtesis funcionales adecuadas en los pacientes sometidos a reconstrucción del LCA. Las lesiones de LCA en esquiadores de nivel competitivo son habituales, de manejo específico y multidisciplinario. La elección del injerto y del tipo de rehabilitación son fundamentales en el retorno deportivo del esquiador. NIVEL DE EVIDENCIA: V.

Skiing is an individual sport with an injury rate of 1.84 per 1,000 skier days among the general population. Anterior cruciate ligament (ACL) tears are among the most common injuries in skiers, with a rate of 5 per 100 skiers per season at a competitive level, because of the great demand placed on the knees. Their treatment is a challenge for orthopedic surgeons. A review of the literature was carried out regarding injury mechanisms, treatment, prevention, rehabilitation, and the use of bracing in the return to sports. The classic injury mechanisms in amateur and competitive skiers are described. Most ACL injuries require surgical resolution, with reconstruction using autologous bone-patellar tendon-bone graft, except in older patients or those with open physis, who must receive an autologous semitendinosusgracilis graft. Prevention and rehabilitation are based on improving strength and neuromuscular control of the dynamic knee stabilizers, implementing specific programs, evaluating the sport movements, and performing neuromuscular control tests. Suitable functional bracings are recommended in patients undergoing ACL reconstruction. ACL injuries in competitive-level skiers are common, and their management is specific and multidisciplinary. The choice of graft and rehabilitation type is critical to resume skiing. LEVEL OF EVIDENCE: V.

Liver transplantation for hepatocellular carcinoma: impact of expansion criteria in a multicenter cohort study from a high waitlist mortality region.

This study aimed to compare liver transplantation (LT) outcomes and evaluate the potential rise in numbers of LT candidates with hepatocellular carcinoma (HCC) of different allocation policies in a high waitlist mortality region. Three policies were applied in two Latin American cohorts (1085 HCC transplanted patients and 917 listed patients for HCC): (i) Milan criteria with expansion according to UCSF downstaging (UCSF-DS), (ii) the AFP score, and (iii) restrictive policy or Double Eligibility Criteria (DEC; within Milan + AFP score ≤2). Increase in HCC patient numbers was evaluated in an Argentinian prospective validation set (INCUCAI; NCT03775863). Expansion criteria in policy A showed that UCSF-DS [28.4% (CI 12.8-56.2)] or "all-comers" [32.9% (CI 11.9-71.3)] had higher 5-year recurrence rates compared to Milan, with 10.9% increase in HCC patients for LT. The policy B showed lower recurrence rates for AFP scores ≤2 points, even expanding beyond Milan criteria, with a 3.3% increase. Patients within DEC had lower 5-year recurrence rates compared with those beyond DEC [13.3% (CI 10.1-17.3) vs 24.2% (CI 17.4-33.1; P = 0.0006], without significant HCC expansion. In conclusion, although the application of a stricter policy may optimize the selection process, this restrictive policy may lead to ethical concerns in organ allocation (NCT03775863).

Recurrence of hepatocellular carcinoma after liver transplantation: Prognostic and predictive factors of survival in a Latin American cohort.

BACKGROUND & AIM: Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) has a poor prognosis, and the adjusted effect of different treatments on post-recurrence survival (PRS) has not been well defined. This study aims to evaluate prognostic and predictive variables associated with PRS. METHODS: This Latin American multicenter retrospective cohort study included HCC patients who underwent LT between the years 2005-2018. We evaluated the effect of baseline characteristics at time of HCC recurrence diagnosis and PRS (Cox regression analysis). Early recurrences were those occurring within 12 months of LT. To evaluate the adjusted treatment effect for HCC recurrence, a propensity score matching analysis was performed to assess the probability of having received any specific treatment for recurrence. RESULTS: From a total of 1085 transplanted HCC patients, the cumulative incidence of recurrence was 16.6% (CI 13.5-20.3), with median time to recurrence of 13.0 months (IQR 6.0-26.0). Factors independently associated with PRS were early recurrence (47.6%), treatment with sorafenib and surgery/trans-arterial chemoembolization (TACE). Patients who underwent any treatment presented "early recurrences" less frequently, and more extrahepatic metastasis. This unbalanced distribution was included in the propensity score matching, with correct calibration and discrimination (receiving operator curve of 0.81 [CI 0.72;0.88]). After matching, the adjusted effect on PRS for any treatment was HR of 0.2 (0.10;0.33); P < .0001, for sorafenib therapy HR of 0.4 (0.27;0.77); P = .003, and for surgery/TACE HR of 0.4 (0.18;0.78); P = .009. CONCLUSION: Although early recurrence was associated with worse outcome, even in this population, systemic or locoregional treatments were associated with better PRS.

Direct-Acting Antivirals and Hepatocellular Carcinoma: No Evidence of Higher Wait-List Progression or Posttransplant Recurrence.

The association between direct-acting antivirals (DAAs) and hepatocellular carcinoma (HCC) wait-list progression or its recurrence following liver transplantation (LT) remains uncertain. We evaluated the impact of DAAs on HCC wait-list progression and post-LT recurrence. This Latin American multicenter retrospective cohort study included HCC patients listed for LT between 2012 and 2018. Patients were grouped according to etiology of liver disease: hepatitis C virus (HCV) negative, HCV+ never treated with DAAs, and HCV+ treated with DAAs either before or after transplantation. Multivariate competing risks models were conducted for both HCC wait-list progression adjusted by a propensity score matching (pre-LT DAA effect) and for post-LT HCC recurrence (pre- or post-LT DAA effect). From 994 included patients, 50.6% were HCV-, 32.9% were HCV+ never treated with DAAs, and 16.5% were HCV+ treated with DAAs either before (n = 66) or after LT (n = 98). Patients treated with DAAs before LT presented similar cumulative incidence of wait-list tumor progression when compared with those patients who were HCV+ without DAAs (26.2% versus 26.9%; P = 0.47) and a similar HCC-related dropout rate (12.1% [95% CI, 0.4%-8.1%] versus 12.9% [95% CI, 3.8%-27.2%]), adjusted for baseline tumor burden, alpha-fetoprotein values, HCC diagnosis after listing, bridging therapies, and by the probability of having received or not received DAAs through propensity score matching (subhazard ratio [SHR], 0.9; 95% CI, 0.6-1.6; P = 0.95). A lower incidence of posttransplant HCC recurrence among HCV+ patients who were treated with pre- or post-LT DAAs was observed (SHR, 0.7%; 95% CI, 0.2%-4.0%). However, this effect was confounded by the time to DAA initiation after LT. In conclusion, in this multicenter cohort, HCV treatment with DAAs did not appear to be associated with an increased wait-list tumor progression and HCC recurrence after LT.

Echinococcus Granulosus in the Endangered Patagonian Huemul (Hippocamelus bisulcus).

Cystic echinococcosis (CE) is a zoonotic parasitic disease associated with Echinococcus granulosus. The parasite is maintained by domestic and wild canids as definitive hosts with several ungulate species as intermediate hosts in domestic and peridomestic transmission cycles. In Chile, CE is endemic, and the role of livestock and dogs (Canis lupus familiaris) in the cycle and the accidental infection of humans are widely documented at rural sites. However, the role of wild herbivores in wild cycles or the potential transmission of CE from livestock is still unknown in Chile and the rest of South America. We used molecular techniques to describe CE infecting a Patagonian huemul (Hippocamelus bisulcus) in Cerro Castillo National Reserve (Aysén region, Chile). We make inferences about the risk of disease spillover from sympatric domestic and wild species. The DNA-based molecular analysis revealed that the huemul was infected with E. granulosus G1 genotype, sharing haplotypes with other G1 samples collected from sheep (Ovis aries) and cattle (Bos taurus) worldwide. Geographic overlap between sheep and huemul populations in the reserve likely facilitates parasite spillover into wild deer populations, with shepherd or stray dogs and wild foxes (Lycalopex culpaeus) potentially acting as bridging hosts between livestock and the endangered huemul. Further studies are warranted to understand the implications of E. granulosus for huemul conservation throughout the Chilean Patagonia.

Characterization of the antagonist actions of 5-BDBD at the rat P2X4 receptor.

P2X receptors (P2XRs) are a family of ATP-gated ionic channels that are expressed in numerous excitable and non-excitable cells. Despite the great advance on the structure and function of these receptors in the last decades, there is still lack of specific and potent antagonists for P2XRs subtypes, especially for the P2X4R. Here, we studied in detail the effect of the P2X4R antagonist 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) on ATP-induced currents mediated by the rat P2X4R and compared its specificity among another rat P2XRs. We found that 5-BDBD is a potent P2X4R antagonist, with an IC50 of 0.75 µM when applied for 2 min prior and during ATP stimulation. Moreover, at 10 µM concentration, 5-BDBD did not affect the ATP-induced P2X2aR, P2X2bR, and P2X7R current amplitude or the pattern of receptor desensitization. However, at 10 µM concentration but not 0.75 µM 5-BDBD inhibited the P2X1R and P2X3R-gated currents by 13 and 35% respectively. Moreover, we studied the effects of 5-BDBD in long-term potentiation experiments performed in rat hippocampal slices, finding this antagonist can partially decrease LTP, a response that is believed to be mediated in part by endogenous P2X4Rs. These results indicate that 5-BDBD could be used to study the endogenous effects of the P2X4R in the central nervous system and this antagonist can discriminate between P2X4R and other P2XRs, when they are co-expressed in the same tissue.

Evaluación de los resultados del trasplante hepático con hígados que nadie quiere / Result evaluation of liver transplantation with livers that nobody wants

INTRODUCCIÓN: La escasez de donantes para suplir la demanda de trasplantes es un problema Mundial. "Hígados que nadie quiere" (HNQ) define injertos que fueron rechazados numerosas veces por varios centros antes de su aceptación. OBJETIVO: evaluar los resultados en la utilización de "HNQ" en nuestro centro. Fuente de datos CRESI-SINTRA y una base prospectiva, Periodo 2013-2016. MÉTODOS: Estudio retrospectivo, dos grupos pre-determinados: 1. Pacientes que recibieron un órgano más allá del percentilo 75 de mediana de rechazos 2. Resto de los receptores. RESULTADOS: Se realizaron 1325 trasplantes a nivel nacional, con una mediana de rechazos previos al implante de 5 (IQR3-11). 153 fueron realizados en el HEC y la mediana de rechazos fue de 7 (IQR3-18); 55/36% de esos injertos mas allá de p75, ninguno fue usado para falla fulminante. Comparando 1 vs 2 (55 vs 72), no hubo diferencias estadísticamente significativas en la edad (51 años IQR45-60 vs 50 años IQR39-59 p=0.53), incidencia de falla primaria del injerto (RR 0.65 IC95%0.33-1.32 p=0.19), extubacion temprana (RR 1.16 IC95%0.43-3.16p=0.78),o diálisis (RR 1.36 IC95%0.84-2.21 p=0.26); tampoco en la duración de estadía en UTI (4 días IQR3-6 vs 5 días IQR 3-9 p=0.12) u hospitalaria (8 días IQR 6-14 vs 1.5 días IQR 8-17.5 p=0.06), sobrevida del injerto (p=0.51) y del paciente (p=0.59). El MELD del receptor fue la única diferencia (24 IQR22-25 vs 28 IQR25-33 p<0.05: Un tercio de la población de nuestro centro recibió "HNQ" (injertos rechazados previamente 12 veces), con similares resultados. Futuras investigaciones deberían determinar la causa de esos rechazos.

INTRODUCTION: Donor scarcity to supply the demand for transplants is a global problem. "Livers that nobody wants" (LNW) are those grafts that were refused by several centers multiple times before being accepted. OBJECTIVE: to evaluate the results in the use of "LNW" in our center. Data source: CRESI-SINTRA and a prospective database, period 2013-2016. METHODS: Retrospective study in two predetermined groups: 1. Patients who received an organ beyond the 75th percentile of median rejections 2. The rest of recipients. RESULTS: At national level, 1325 transplantations were made, its median refusals prior to implantation being 5 (IQR3-11), of which 153 were made in the HEC and the median refusals were 7 (IQR3-18); out of 55/36% of these grafts beyond the 75th p, none were used in fulminant hepatic failure. In comparing 1 vs 2 groups (55 vs 72), there were no statistically significant differences in age (51 years IQR45-60 vs 50 years IQR39-59 p=0.53), incidence ofdraft primary failure (RR 0.65 IC95%0.33-1.32 p=0.19), early extubation (RR 1.16 IC95%0.43- 3.16p=0.78),or dialysis requirement (RR 1.36 IC95%0.84-2.21 p=0.26); there were no differences either in the ICU stay (4 days IQR3-6 vs 5 days IQR 3-9 p=0.12) or in hospital stay(8 days IQR 6-14 vs 1.5 days IQR 8-17.5 p=0.06), draft survival (p=0.51) and patient survival (p=0.59). The only difference was in the MELD score of the receptor (24 IQR22-25 vs 28 IQR25-33 p<0.05:). A third of the population in our center received LNW (drafts previously refused 12 times) and showed similar results. The cause of these refusals should be determined by future research.

Biomonitoring of blood cholinesterases and acylpeptide hydrolase activities in rural inhabitants exposed to pesticides in the Coquimbo Region of Chile.

In Chile, agriculture is a relevant economic activity and is concomitant with the use of pesticides to improve the yields. Acute intoxications of agricultural workers occur with some frequency and they must be reported to the surveillance system of the Ministry of Health. However the impacts of chronic and environmental pesticide exposure have been less studied. Among pesticides frequently used in Chile for insects control are organophosphates (OP) and carbamates (CB). They are inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). In this study we determined the pattern of both biomarkers activity in three populations with different type of chronic exposure to OP/CB: environmentally exposed (EE), occupationally exposed (OE) and a reference group (RG) without exposure. Besides this, we also measured the activity of acylpeptide hydrolase (APEH), an enzyme involved in relevant functions in the central synapses that is also expressed in erythrocytes and previously reported to be highly inhibited by some OP. A baseline measurement was done in both exposure groups and then a second measurement was done during the spraying season. The RG was measured only once at any time of the year. Our results indicate that people under chronic OP/CB exposure showed an adaptive response through an increase of basal BChE activity. During the spray season only BChE activity was decreased in the EE and OE groups (p<0.05 and p<0.01, respectively) and the higher magnitude of BChE inhibition was observed in the EE group. The analysis of the frequencies of inhibition above 30% (biological tolerance limit declared by Chilean legislation) indicated that BChE was most frequently inhibited in the EE group (53% of the individuals displayed inhibition) and AChE in the OE group (55% of the individuals displayed AChE inhibition). APEH activity showed the highest frequency of inhibition in the EE group independent of its magnitude (64%). Our results demonstrate that the rural population living nearby agricultural settings displays high levels of environmental exposure. APEH activity seems to be a sensitive biomarker for acute low-level exposure and its usefulness as a routine biomarker must to be explored in future studies. Systematic biomonitoring and health outcomes studies are necessary as well as obtaining the baseline for BChE and AChE activity levels with the aim to improve environmental and occupational health policies in Chile.

In Vivo Sub-chronic Treatment with Dichlorvos in Young Rats Promotes Synaptic Plasticity and Learning by a Mechanism that Involves Acylpeptide Hydrolase Instead of Acetylcholinesterase Inhibition. Correlation with Endogenous ß-Amyloid Levels.

Acylpeptide hydrolase (APEH) is a serine hydrolase that displays two catalytic activities, acting both as an exopeptidase toward short N-acylated peptides and as an endopeptidase toward oxidized peptides or proteins. It has been demonstrated that this enzyme can degrade monomers, dimers, and trimers of the Aß1-40 peptide in the conditioned media of neuroblastoma cells. In a previous report, we showed that the specific inhibition of this enzyme by the organophosphate molecule dichlorvos (DDVP) triggers an enhancement of long-term potentiation in rat hippocampal slices. In this study, we demonstrate that the same effect can be accomplished in vivo by sub-chronic treatment of young rats with a low dose of DDVP (0.1 mg/kg). Besides exhibiting a significant enhancement of LTP, the treated animals also showed improvements in parameters of spatial learning and memory. Interestingly, higher doses of DDVP such as 2 mg/kg did not prove to be beneficial for synaptic plasticity or behavior. Due to the fact that at 2 mg/kg we observed inhibition of both APEH and acetylcholinesterase, we interpret that in order to achieve positive effects on the measured parameters only APEH inhibition should be obtained. The treatment with both DDVP doses produced an increase in the endogenous concentration of Aß1-40, although this was statistically significant only at the dose of 0.1 mg/kg. We propose that APEH represents an interesting pharmacological target for cognitive enhancement, acting through the modulation of the endogenous concentration of Aß1-40.

Cyclin-dependent kinase 5 modulates the P2X2a receptor channel gating through phosphorylation of C-terminal threonine 372.

The purinergic P2X2 receptor (P2X2R) is an adenosine triphosphate-gated ion channel widely expressed in the nervous system. Here, we identified a putative cyclin-dependent kinase 5 (Cdk5) phosphorylation site in the full-size variant P2X2aR (TPKH), which is absent in the splice variant P2X2bR. We therefore investigated the effects of Cdk5 and its neuronal activator, p35, on P2X2aR function. We found an interaction between P2X2aR and Cdk5/p35 by co-immunofluorescence and co-immunoprecipitation in HEK293 cells. We also found that threonine phosphorylation was significantly increased in HEK293 cells co-expressing P2X2aR and p35 as compared to cells expressing only P2X2aR. Moreover, P2X2aR-derived peptides encompassing the Cdk5 consensus motif were phosphorylated by Cdk5/p35. Whole-cell patch-clamp recordings indicated a delay in development of use-dependent desensitization (UDD) of P2X2aR but not of P2X2bR in HEK293 cells co-expressing P2X2aR and p35. In Xenopus oocytes, P2X2aRs showed a slower UDD than in HEK293 cells and Cdk5 activation prevented this effect. A similar effect was found in P2X2a/3R heteromeric currents in HEK293 cells. The P2X2aR-T372A mutant was resistant to UDD. In endogenous cells, we observed similar distribution between P2X2R and Cdk5/p35 by co-localization using immunofluorescence in primary culture of nociceptive neurons. Moreover, co-immunoprecipitation experiments showed an interaction between Cdk5 and P2X2R in mouse trigeminal ganglia. Finally, endogenous P2X2aR-mediated currents in PC12 cells and P2X2/3R mediated increases of intracellular Ca in trigeminal neurons were Cdk5 dependent, since inhibition with roscovitine accelerated the desensitization kinetics of these responses. These results indicate that the P2X2aR is a novel target for Cdk5-mediated phosphorylation, which might play important physiological roles including pain signaling.

Catalytic autoantibodies against myelin basic protein (MBP) isolated from serum of autistic children impair in vitro models of synaptic plasticity in rat hippocampus.

Autoantibodies from autistic spectrum disorder (ASD) patients react with multiple proteins expressed in the brain. One such autoantibody targets myelin basic protein (MBP). ASD patients have autoantibodies to MBP of both the IgG and IgA classes in high titers, but no autoantibodies of the IgM class. IgA autoantibodies act as serine proteinases and degrade MBP in vitro. They also induce a decrease in long-term potentiation in the hippocampi of rats either perfused with or previously inoculated with this IgA. Because this class of autoantibody causes myelin sheath destruction in multiple sclerosis (MS), we hypothesized a similar pathological role for them in ASD.

Assessing biomarkers and neuropsychological outcomes in rural populations exposed to organophosphate pesticides in Chile--study design and protocol.

BACKGROUND: Health effects of pesticides are easily diagnosed when acute poisonings occurs, nevertheless, consequences from chronic exposure can only be observed when neuropsychiatric, neurodegenerative or oncologic pathologies appear. Therefore, early monitoring of this type of exposure is especially relevant to avoid the consequences of pathologies previously described; especially concerning workers exposed to pesticides on the job. For acute organophosphate pesticides (OPP) exposure, two biomarkers have been validated: plasma cholinesterase (ChE) and acetylcholinesterase (AChE) from erythrocytes. These enzymes become inhibited when people are exposed to high doses of organophosphate pesticides, along with clear signs and symptoms of acute poisoning; therefore, they do not serve to identify risk from chronic exposure. This study aims to assess a novel biomarker that could reflect neuropsychological deterioration associated with long-term exposure to organophosphate pesticides via the enzyme acylpeptide-hydrolase (ACPH), which has been recently identified as a direct target of action for some organophosphate compounds. METHODS/DESIGN: Three population groups were recruited during three years (2011-2013): Group I having no exposure to pesticides, which included people living in Chilean coastal areas far from farms (external control); Group II included those individuals living within the rural and farming area (internal control) but not occupationally exposed to pesticides; and Group III living in rural areas, employed in agricultural labour and having had direct contact with pesticides for more than five years. Blood samples to assess biomarkers were taken and neuropsychological evaluations carried out seasonally; in three time frames for the occupationally exposed group (before, during and after fumigation period); in two time frames for internal control group (before and during fumigation), and only once for the external controls. Neuropsychological evaluations considered cognitive functions, affectivity and psychomotor activity. The biomarkers measured included ChE, AChE and ACPH. Statistical analysis and mathematical modelling used both laboratory results and neuropsychological testing outcomes in order to assess whether ACPH would be acceptable as biomarker for chronic exposure to OPP. DISCUSSION: This study protocol has been implemented successfully during the time frames mentioned above for seasons 2011, 2012 and 2013-2014.

Monoamniotic twin pregnancy discordant for lethal open cranial defect: management dilemmas.

OBJECTIVE: To report the sonographic findings, prenatal courses, and management options in four cases of monoamniotic twin pregnancy complicated by a discordant, lethal open cranial vault defect. METHODS: Cases were collected from two Latin American fetal medicine referral centers after the sonographic detection of a monoamniotic twin pregnancy in which one fetus was structurally normal and the other had a lethal open cranial vault defect. Three abnormal fetuses had acrania-anencephaly sequence and one had a large occipital encephalocele. The diagnosis was confirmed at referral, at which time umbilical cord entanglement was also diagnosed with color Doppler ultrasound in all cases. RESULTS: Two cases were managed with selective termination, one of which required referral to a fetal surgery center abroad because this option was illegal in Chile. The other case underwent radiofrequency ablation of the fetal intra-abdominal umbilical vessels after the corresponding ethics and legal committees approved the procedure. In both cases, the non-anomalous twin was born after 35 weeks and had no perinatal complications. Expectant management was performed in the other two cases, resulting in the death of the normal twin at 25 weeks. CONCLUSIONS: Monoamniotic twin pregnancy discordant for severe cranial vault defect is a serious condition with a high risk of fetal demise of the structurally normal fetus. Our experience, although limited, suggests that aggressive management with selective termination of the abnormal twin and transection of its umbilical cord in these cases may prevent the demise of the structurally normal co-twin.

[Bilateral mature teratoma and pregnancy: case report]. / Teratoma bilateral maduro y embarazo: reporte de un caso.

We report a case of a 21 years old woman, pregnant (14.1 weeks of gestation), and with 24 hours of abdominal pain received at the emergency room. During examination we found gravid uterus and a mass in the right inguinal area and flank, independent from uterus, painful and with no uterine activity. We perform an obstetric ultrasound with this results: 13 weeks pregnancy and right adnexal cystic tumor with 15 x 14 cm. Patient undergo to emergency exploratory laparotomy, with previous application of indomethacin end progesterone. During surgery performance we observe a bilateral adnexal masse, right side affecting the complete ovary (salpingactomized), and left side extirpated leaving functional tissue ovary. Three days after, patient leaves the hospital without any complication. Pathology reports a bilateral mature teratoma.

[Benign senile pyometra: case report]. / Piometra senil benigno: comunicación de un caso.

Pyometra is a pus accumulation in the endometrium cavity, with an incidence from 0.02% to 1.5%. The benign senile pyometra is a disease mainly reported in elder women, with an average age of 74 years. We present the case of a 59-year-old woman with the diagnosis of benign senile pyometra. The patient came to our service presenting purulent vaginal discharge, in bad condition with pelvic pain and altered hematic cytology. In the physical examination a pelvic mass was found, in the vaginal examination, the cervix was found estenotic, and the hysterometer could not be introduced. The image studies revealed an increased size of the uterus was liquid collection in its interior, compatible with blood or pus. We performed exploratory laparotomy, founding two abscecess in the uterin fundus which suffered rupture during the procedure. Abdominal hysterectomy with bilateral salpigooforectomy was performed, there were not other complications. Post surgical period was managed with antibiotics and close surveillance. The patient was discharged four days later with good response to the treatment. In the anatomophatological study no evidence of cervical or endometrial neoplasia was found.