Automated Patch Clamp Screening of Amiloride and 5-N,N-Hexamethyleneamiloride Analogs Identifies 6-Iodoamiloride as a Potent Acid-Sensing Ion Channel Inhibitor.

Acid-sensing ion channels (ASICs) are transmembrane sensors of extracellular acidosis and potential drug targets in several disease indications, including neuropathic pain and cancer metastasis. The K+-sparing diuretic amiloride is a moderate nonspecific inhibitor of ASICs and has been widely used as a probe for elucidating ASIC function. In this work, we screened a library of 6-substituted and 5,6-disubstituted amiloride analogs using a custom-developed automated patch clamp protocol and identified 6-iodoamiloride as a potent ASIC1 inhibitor. Follow-up IC50 determinations in tsA-201 cells confirmed higher ASIC1 inhibitory potency for 6-iodoamiloride 94 (hASIC1 94 IC50 = 88 nM, cf. amiloride 11 IC50 = 1.7 µM). A similar improvement in activity was observed in ASIC3-mediated currents from rat dorsal root ganglion neurons (rDRG single-concentration 94 IC50 = 230 nM, cf. 11 IC50 = 2.7 µM). 6-Iodoamiloride represents the amiloride analog of choice for studying the effects of ASIC inhibition on cell physiology.

Challenges in the management of Covid-19 patients in a neurological center in Mexico City.

Not available.

Prion Strain Differences in Accumulation of PrPSc on Neurons and Glia Are Associated with Similar Expression Profiles of Neuroinflammatory Genes: Comparison of Three Prion Strains.

Misfolding and aggregation of host proteins are important features of the pathogenesis of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, frontotemporal dementia and prion diseases. In all these diseases, the misfolded protein increases in amount by a mechanism involving seeded polymerization. In prion diseases, host prion protein is misfolded to form a pathogenic protease-resistant form, PrPSc, which accumulates in neurons, astroglia and microglia in the CNS. Here using dual-staining immunohistochemistry, we compared the cell specificity of PrPSc accumulation at early preclinical times post-infection using three mouse scrapie strains that differ in brain regional pathology. PrPSc from each strain had a different pattern of cell specificity. Strain 22L was mainly associated with astroglia, whereas strain ME7 was mainly associated with neurons and neuropil. In thalamus and cortex, strain RML was similar to 22L, but in substantia nigra, RML was similar to ME7. Expression of 90 genes involved in neuroinflammation was studied quantitatively using mRNA from thalamus at preclinical times. Surprisingly, despite the cellular differences in PrPSc accumulation, the pattern of upregulated genes was similar for all three strains, and the small differences observed correlated with variations in the early disease tempo. Gene upregulation correlated with activation of both astroglia and microglia detected in early disease prior to vacuolar pathology or clinical signs. Interestingly, the profile of upregulated genes in scrapie differed markedly from that seen in two acute viral CNS diseases (LaCrosse virus and BE polytropic Friend retrovirus) that had reactive gliosis at levels similar to our prion-infected mice.

High bioavailability curcumin: an anti-inflammatory and neurosupportive bioactive nutrient for neurodegenerative diseases characterized by chronic neuroinflammation.

Neuroinflammation is a pathophysiological process present in a number of neurodegenerative disorders, such as Alzheimer's disease, Huntington's disease, Parkinson's disease, stroke, traumatic brain injury including chronic traumatic encephalopathy and other age-related CNS disorders. Although there is still much debate about the initial trigger for some of these neurodegenerative disorders, during the progression of disease, broad range anti-inflammatory drugs including cytokine suppressive anti-inflammatory drugs (CSAIDs) might be promising therapeutic options to limit neuroinflammation and improve the clinical outcome. One of the most promising CSAIDs is curcumin, which modulates the activity of several transcription factors (e.g., STAT, NF-κB, AP-1) and their pro-inflammatory molecular signaling pathways. However, normal curcumin preparations demonstrate low bioavailability in vivo. To increase bioavailability, preparations of high bioavailability curcumin have been introduced to achieve therapeutically relevant concentrations in target tissues. This literature review aims to summarize the pharmacokinetic and toxicity profile of different curcumin formulations.

Vitamin D3 (Calcitriol) Monotherapy Decreases Tumor Growth, Increases Survival, and Correlates with Low Neutrophil-to-Lymphocyte Ratio in a Murine HPV-16-Related Cancer Model.

Vitamin D3 or calcitriol (VitD3) has been shown to have anticancer and anti-inflammatory activity in in vitro models and clinical studies. However, its effect on HPV-16-related cancer has been sparsely explored. In this study, we aimed to determine whether monotherapy or combination therapy with cisplatin (CP) reduces tumor growth and affects survival and systemic inflammation. Treatments were administered to C57BL/6 mice with HPV-16-related tumors (TC-1 cells) as follows: (1) placebo (100 µL vehicle, olive oil, orally administered daily); (2) VitD3 (3.75 µg/kg calcitriol orally administered daily); (3) CP (5 mg/kg intraperitoneally, every 7 days); and (4) VitD3+CP. Tumor growth was monitored for 25 days, survival for 60 days, and the neutrophil-to-lymphocyte ratio (NLR) was evaluated on days 1 (baseline), 7, and 14. VitD3+CP showed greater success in reducing tumor volume compared to CP monotherapy (p = 0.041), while no differences were observed between CP and VitD3 monotherapy (p = 0.671). Furthermore, VitD3+CP prolonged survival compared to CP (p = 0.036) and VitD3 (p = 0.007). Additionally, at day 14 the VitD3 and VitD3+CP groups showed significantly lower NLR values than the CP group (p < 0.05, for both comparisons). Vitamin D3 could be a promising adjuvant in the treatment of cervical cancer or solid tumors and deserves further investigation.

Mobile Health and Wellness Project: A binational collaboration of frontline health services to the Latino population in the United States in times of COVID-19.

Hardly reached communities in the United States greatly benefit from collective efforts and partnerships from Community Based Organizations, Health Institutions and Government Agencies, yet the effort to engage in this collaborative effort is minimal and funding to support these projects is lacking. The COVID-19 Pandemic exacerbated on a national scale what many vulnerable communities experience regularly; difficult access to basic medical care, information and support. In an effort to directly engage with community organizations and curb the infection rate of the COVID-19 virus within vulnerable communities, the US Centers for Disease Control and Prevention (CDC) launched its first targeted effort to partner directly with community based organizations. This article will highlight the first pilot year of activities and key results of COVID-19 education and vaccination efforts by the Mobile Health and Wellness project. This is a fleet of 11 Mobile Health Vehicles managed by the Mexico Section US-Mexico Border Health Commission in partnership with Alianza Americas, Latino Commission on AIDS, and the CDC, targeting Latino, Immigrant and rural communities across the US.

Ventanillas de Salud (VDS) and Mobile Health Units (MHU): A binational collaborative models.

Over the years, the Mexican population in the United States has faced high prevalence of health-related inequalities and disadvantages and represents one of the most vulnerable migrant groups in the country. To help reduce the gaps in health care for the Mexican population, the Mexican government, in collaboration with strategic allies from various sectors, launched the Ventanillas de Salud (VDS) strategy, which was subsequently reinforced through the Mobile Health Units (MHU) care model. Both the VDS strategy and the MHU care model are intended to contribute to the development of initiatives, projects, and actions in health that will benefit the Mexican community living in the United States, which lacks or has difficulty accessing health services. This article provides a descriptive, analytical analysis of the VDS strategy and the MHU care model, as unique collaborative models, which can be replicated, and have achieved a positive impact on the health of Mexican and other Hispanic communities in the United States, at both the individual and community level.

"I prefer to get coronavirus than to stop working": the street vendor's perspective.

During phase 2 of the COVID-19 pandemic in a Mexican City, informal street vendors (cases) and formal employees (controls) were interviewed. A total of 82.6% of street vendors preferred to expose themselves to the coronavirus than to stop working, compared with 18.4% of formal employees (adjusted OR = 19.4, 95%CI: 4.6-81.7, p < 0.001). Street vendors had 7 times less fear of dying from coronavirus (adjusted OR = 0.14, 95% CI: 0.03-0.5, p = 0.005) and showed a 16-times greater lack of real concern for the increase in cases in their community than the formal employees (adjusted OR = 0.06, 95% CI: 0.01-0.3, p = 0.002). Street vendors were the group with the poorest adherence to household and work area containment measures that continued to be in contact with others. The corresponding authorities must plan specific strategies that allow street vendors to survive economically, while at the same time, protecting community health.

Safety and efficacy of a COVID-19 treatment with nebulized and/or intravenous neutral electrolyzed saline combined with usual medical care vs. usual medical care alone: A randomized, open-label, controlled trial.

Coronavirus disease 2019 (COVID-19) is currently the major public health problem worldwide. Neutral electrolyzed saline solution that contains reactive chlorine and oxygen species may be an effective therapeutic. In the present study, the treatment efficacy of intravenous and/or nebulized neutral electrolyzed saline combined with usual medical care vs. usual medical care alone was evaluated in ambulatory patients with COVID-19. A prospective, 2-arm, parallel-group, randomized, open-label, multi-center, phase I-II clinical trial including 214 patients was performed. The following two outcomes were evaluated during the 20-day follow-up: i) The number of patients with disease progression; and ii) the patient acceptable symptom state. Serial severe acute respiratory syndrome coronavirus 2 naso/oro-pharyngeal detection by reverse transcription-quantitative (RT-q) PCR was performed in certain patients of the experimental group. Biochemical and hematologic parameters, as well as adverse effects, were also evaluated in the experimental group. The experimental treatment decreased the risk of hospitalization by 89% [adjusted relative risk (RR)=0.11, 95% confidence interval (CI): 0.03-0.37, P<0.001] and the risk of death by 96% (adjusted RR=0.04, 95% CI: 0.01-0.42, P=0.007) and also resulted in an 18-fold higher probability of achieving an acceptable symptom state on day 5 (adjusted RR=18.14, 95% CI: 7.29-45.09, P<0.001), compared with usual medical care alone. Overall, neutral electrolyzed saline solution was better than usual medical care alone. Of the patients analyzed, >50% were negative for the virus as detected by RT-qPCR in naso/oro-pharyngeal samples on day 4, with only a small number of positive patients on day 6. Clinical improvement correlated with a decrease in C-reactive protein, aberrant monocytes and increased lymphocytes and platelets. Cortisol and testosterone levels were also evaluated and a decrease in cortisol levels and an increase in the testosterone-cortisol ratio were observed on days 2 and 4. The experimental treatment produced no serious adverse effects. In conclusion, neutral electrolyzed saline solution markedly reduced the symptomatology and risk of progression in ambulatory patients with COVID-19. The present clinical trial was registered in the Cuban public registry of clinical trials (RPCEC) database (May 5, 2020; no. TX-COVID19: RPCEC00000309).

Neurites regrowth of cortical neurons by GSK3beta inhibition independently of Nogo receptor 1.

Lesioned axons do not regenerate in the adult mammalian CNS, owing to the over-expression of inhibitory molecules such as myelin-derived proteins or chondroitin sulphate proteoglycans. In order to overcome axon inhibition, strategies based on extrinsic and intrinsic treatments have been developed. For myelin-associated inhibition, blockage with NEP1-40, receptor bodies or IN-1 antibodies has been used. In addition, endogenous blockage of cell signalling mechanisms induced by myelin-associated proteins is a potential tool for overcoming axon inhibitory signals. We examined the participation of glycogen synthase kinase 3beta (GSK3beta) and extracellular-related kinase (ERK) 1/2 in axon regeneration failure in lesioned cortical neurons. We also investigated whether pharmacological blockage of GSK3beta and ERK1/2 activities facilitates regeneration after myelin-directed inhibition in two models: (i) cerebellar granule cells and (ii) lesioned entorhino-hippocampal pathway in slice cultures, and whether the regenerative effects are mediated by Nogo Receptor 1 (NgR1). We demonstrate that, in contrast to ERK1/2 inhibition, the pharmacological treatment of GSK3beta inhibition strongly facilitated regrowth of cerebellar granule neurons over myelin independently of NgR1. Finally, these regenerative effects were corroborated in the lesioned entorhino-hippocampal pathway in NgR1-/- mutant mice. These results provide new findings for the development of new assays and strategies to enhance axon regeneration in injured cortical connections.

The sensitivity of patient specific IMRT QC to systematic MLC leaf bank offset errors.

PURPOSE: Patient specific IMRT QC is performed routinely in many clinics as a safeguard against errors and inaccuracies which may be introduced during the complex planning, data transfer, and delivery phases of this type of treatment. The purpose of this work is to evaluate the feasibility of detecting systematic errors in MLC leaf bank position with patient specific checks. METHODS: 9 head and neck (H&N) and 14 prostate IMRT beams were delivered using MLC files containing systematic offsets (+/- 1 mm in two banks, +/- 0.5 mm in two banks, and 1 mm in one bank of leaves). The beams were measured using both MAPCHECK (Sun Nuclear Corp., Melbourne, FL) and the aS1000 electronic portal imaging device (Varian Medical Systems, Palo Alto, CA). Comparisons with calculated fields, without offsets, were made using commonly adopted criteria including absolute dose (AD) difference, relative dose difference, distance to agreement (DTA), and the gamma index. RESULTS: The criteria most sensitive to systematic leaf bank offsets were the 3% AD, 3 mm DTA for MAPCHECK and the gamma index with 2% AD and 2 mm DTA for the EPID. The criterion based on the relative dose measurements was the least sensitive to MLC offsets. More highly modulated fields, i.e., H&N, showed greater changes in the percentage of passing points due to systematic MLC inaccuracy than prostate fields. CONCLUSIONS: None of the techniques or criteria tested is sufficiently sensitive, with the population of IMRT fields, to detect a systematic MLC offset at a clinically significant level on an individual field. Patient specific QC cannot, therefore, substitute for routine QC of the MLC itself.

Micro-CT scan with virtual dissection of left ventricle is a non-destructive, reproducible alternative to dissection and weighing for left ventricular size.

Micro-CT scan images enhanced by iodine staining provide high-resolution visualisation of soft tissues in laboratory mice. We have compared Micro-CT scan-derived left ventricular (LV) mass with dissection and weighing. Ex-vivo micro-CT scan images of the mouse hearts were obtained following staining by iodine. The LV was segmented and its volume was assessed using a semi-automated method by Drishti software. The left ventricle was then dissected in the laboratory and its actual weight was measured and compared against the estimated results. LV mass was calculated multiplying its estimated volume and myocardial specific gravity. Thirty-five iodine-stained post-natal mouse hearts were studied. Mice were of either sex and 68 to 352 days old (median age 202 days with interquartile range 103 to 245 days) at the time of sacrifice. Samples were from 20 genetically diverse strains. Median mouse body weight was 29 g with interquartile range 24 to 34 g. Left Ventricular weights ranged from 40.0 to 116.7 mg. The segmented LV mass estimated from micro-CT scan and directly measured dissected LV mass were strongly correlated (R2 = 0. 97). Segmented LV mass derived from Micro-CT images was very similar to the physically dissected LV mass (mean difference = 0.09 mg; 95% confidence interval - 3.29 mg to 3.1 mg). Micro-CT scanning provides a non-destructive, efficient and accurate visualisation tool for anatomical analysis of animal heart models of human cardiovascular conditions. Iodine-stained soft tissue imaging empowers researchers to perform qualitative and quantitative assessment of the cardiac structures with preservation of the samples for future histological analysis.

Patient-Reported Health Outcomes After Treatment of COVID-19 with Nebulized and/or Intravenous Neutral Electrolyzed Saline Combined with Usual Medical Care Versus Usual Medical care alone: A Randomized, Open-Label, Controlled Trial.

Background: Coronavirus disease (COVID-19) is currently the main public health problem worldwide. The administration of neutral electrolyzed saline, a solution that contains reactive species of chlorine and oxygen (ROS), may be an effective therapeutic alternative due to its immunomodulating characteristics, in systemic inflammation control, as well as in immune response improvement, promoting control of the viral infection. The present study evaluated the efficacy of treatment with intravenous and/or nebulized neutral electrolyzed saline combined with usual medical care versus usual medical care alone, in ambulatory patients with COVID-19. Methods: A prospective, 2-arm, parallel group, randomized, open-label, phase I-II clinical trial included 39 patients in the control group (usual medical care alone) and 45 patients in the experimental group (usual medical care + intravenous and/or nebulized electrolyzed saline, with dose escalation). Two aspects were evaluated during the twenty-day follow-up: i) the number of patients with disease progression (hospitalization or death); and ii) the Patient Acceptable Symptom State (PASS), a single-question outcome that determines patient well-being thresholds for pain and function. Biochemical and hematologic parameters, as well as adverse effects, were evaluated in the experimental group. Results: The experimental treatment decreased the risk for hospitalization by 92% (adjusted RR=0.08, 95% CI: 0.01-0.50, P=0.007), with a 43-fold increase in the probability of achieving an acceptable symptom state on day 5 (adjusted RR= 42.96, 95% CI: 9.22-200.0, P<0.001). Intravenous + nebulized administration was better than nebulized administration alone, but nebulized administration was better than usual medical care alone. Clinical improvement correlated with a decrease in C-reactive protein, and aberrant monocytes and an increase of lymphocytes, and platelets. Cortisol and testosterone levels were also evaluated, observing a decrease in cortisol levels and an increment of testosterone-cortisol ratio, on days 2 and 4. Conclusions: The experimental treatment produced no serious adverse effects. In conclusion, intravenous and/or nebulized neutral electrolyzed saline importantly reduced the symptomatology and risk of progression (hospitalization and death), in ambulatory patients with COVID-19. Trial registration: Cuban Public Registry of Clinical Trials (RPCEC) Database RPCEC00000309. Registered: 05. May 2020. https://rpcec.sld.cu/en/trials/RPCEC00000309-En.

Tolerances on MLC leaf position accuracy for IMRT delivery with a dynamic MLC.

The objective determination of performance standards for radiation therapy equipment requires, ideally, establishing the quantitative relationship between performance deviations and clinical outcome or some acceptable surrogate. In this simulation study the authors analyzed the dosimetric impact of random (leaf by leaf) and systematic (entire leaf bank) errors in the position of the MLC leaves on seven clinical prostate and seven clinical head and neck IMRT plans delivered using a dynamic MLC. In-house software was developed to incorporate normally distributed errors of up to +/- 2 mm in individual leaf position or systematic errors (+/- 1 and +/- 0.5 mm in all leaves of both leaf banks or +1 mm in one bank only) into the 14 plans, thus simulating treatment delivery using a suboptimally performing MLC. The dosimetric consequences of suboptimal MLC performance were quantified using the equivalent uniform doses (EUDs) of the clinical target volumes and important organs at risk (OARs). The deviation of the EUDs of the selected structures as the performance of the MLC deteriorated was used as the objective surrogate of clinical outcome. Random errors of 2 mm resulted in negligible changes for all structures of interest in both sites. In contrast, systematic errors can lead to potentially significant dosimetric changes that may compromise clinical outcome. If a 2% change in EUD of the target and 2 Gy for the OARs were adopted as acceptable levels of deviation in dose due to MLC effects alone, then systematic errors in leaf position will need to be limited to 0.3 mm. This study provides guidance, based on a dosimetric surrogate of clinical outcome, for the development of one component, leaf position accuracy of performance standards for multileaf collimators.

Chronic Microglial Activation in the GFAP-IL6 Mouse Contributes to Age-Dependent Cerebellar Volume Loss and Impairment in Motor Function.

Chronic microglial activation is a prominent feature of many chronic neurodegenerative diseases, including Parkinson's and Alzheimer's disease. To investigate the effects of chronic microglial activation on cerebellar structure and motor function throughout the lifespan, the transgenic GFAP-IL6 mouse model was used. The aim of the study was to examine inflammatory markers and neuronal degeneration while simultaneously characterizing the motor performance of GFAP-IL6 mice at 3, 6, 14, and 24 months of age in comparison to WT (C57BL/6) mice. In respect to markers of neuroinflammation in the cerebellum, increased numbers of Iba1+ microglia were observed as early as at 3 months of age. In addition, TNF-α levels proved to be significantly higher in the GFAP-IL6 compared to WT mice at all time points. A difference in cerebellar volume between the GFAP-IL6 and WT mice was observed later in life, starting at 6 months and increasing to a loss of about 50% in aged (24 months old) GFAP-IL6 mice. Synaptic deficits were also assessed by using pre- (synaptophysin) and post-synaptic (PSD95) markers. While synaptophysin levels remained unchanged, PSD95 levels decreased in the aging GFAP-IL6 mice compared to their WT littermates from 14 months onward. To assess the effect of microglia activation and neurodegeneration on behavior, a variety of motor function tests, semi-quantitative cerebellar ataxia score, accelerod, beam walking, and open field tests were performed. An age-dependent difference between the genotypes was observed in many of the motor function tests. For example, reduced performance on the accelerod and higher ataxia scores were observed at 6 months of age, followed by the beam walking test showing differences at 14 months of age. In summary, this study constitutes a comprehensive, age-dependent examination of inflammatory, synaptic and neurodegenerative changes in the brains of GFAP-IL6 mice leading to a deterioration in motor performance. The results also indicate that early chronic microglia activation in the GFAP-IL6 mouse leads to observable cerebellar volume loss and motor deficits later in life.

Fibrillar prion peptide PrP(106-126) treatment induces Dab1 phosphorylation and impairs APP processing and Abeta production in cortical neurons.

Alzheimer's disease and prion diseases (e.g., Creutzfeldt-Jakob disease) display profound neural lesions associated with aberrant protein processing and extracellular amyloid deposits. However, the intracellular events in prion diseases and their relation with the processing of the amyloid precursor protein (APP) and beta-amyloid generation are unknown. The adaptor protein Dab1 may regulate intracellular trafficking and secretase-mediated proteolysis in APP processing. However, a putative relationship between prion diseases and Dab1/APP interactions is lacking. Thus, we examined, in inoculated animals, whether Dab1 and APP processing are targets of the intracellular events triggered by extracellular exposure to PrP(106-126) peptide. Our in vitro results indicate that PrP(106-126) peptide induces tyrosine phosphorylation of Dab1 by activated members of the Src family of tyrosine kinases (SFK), which implies further Dab1 degradation. We also corroborate these results in Dab1 protein levels in prion-inoculated hamsters. Finally, we show that fibrillar prion peptides have a dual effect on APP processing and beta-amyloid production. First, they block APP trafficking at the cell membrane, thus decreasing beta-amyloid production. In parallel, they reduce Dab1 levels, which also alter APP processing. Lastly, neuronal cultures from Dab1-deficient mice showed severe impairment of APP processing with reduced sAPP secretion and A beta production after prion peptide incubation. Taken together, these data indicate a link between intracellular events induced by exposure to extracellular fibrillar peptide or PrP(res), and APP processing and implicate Dab1 in this link.

Phantom evaluation of a commercially available three modality image guided radiation therapy system.

The authors describe a detailed evaluation of the capabilities of imaging and image registration systems available with Varian linear accelerators for image guided radiation therapy (IGRT). Specifically, they present modulation transfer function curves for megavoltage planar, kilovoltage (kV) planar, and cone beam computed tomography imaging systems and compare these with conventional computed tomography. While kV planar imaging displayed the highest spatial resolution, all IGRT imaging techniques were assessed as adequate for their intended purpose. They have also characterized the image registration software available for use in conjunction with these imaging systems through a comprehensive phantom study involving translations in three orthogonal directions. All combinations of imaging systems and image registration software were found to be accurate, although the planar kV imaging system with automatic registration was generally superior, with both accuracy and precision of the order of 1 mm, under the conditions tested. Based on their phantom study, the attainable accuracy for rigid body translations using any of the features available with Varian equipment will more likely be limited by the resolution of the couch readouts than by inherent limitations in the imaging systems and image registration software. Overall, the accuracy and precision of currently available IGRT technology exceed published experience with the accuracy and precision of contouring for planning.

Evaluation of linear accelerator performance standards using an outcome oriented approach.

Radiation therapy, along with other branches of medicine, is moving towards a firmer basis in evidence to optimally utilize resources. As new treatment technology and strategies place greater demands on quality assurance resources, the need to objectively evaluate equipment and process performance standards from the perspective of predicted clinical impact becomes more urgent. This study evaluates the appropriateness of recommended quality control tolerance and action levels for linear accelerators based on the calculated dosimetric impact of suboptimal equipment performance. A method is described to quantify the dosimetric changes, as reflected by the changes in the outcome surrogate, equivalent uniform dose (EUD), of machine performance deviations from the optimal, specifically in the range of tolerance and action levels promulgated by the Canadian Association of Provincial Cancer Agencies (CAPCA). Linear accelerator performance deviations were simulated for the treatment of prostate, breast, lung, and brain using 3D conformal techniques, and the impact evaluated in terms of the changes in the EUD of the target volumes and two principal organs at risk (OARs) per site. The eight key performance characteristics examined are: Output constancy, beam flatness, gantry angle, collimator angle, field size indicator, laser alignment (three directions) and, by inference, the optical distance indicator. Currently accepted CAPCA tolerance levels for these eight performance characteristics are shown to maintain average EUD deviations to within 2% for the targets and 2 Gy for the OARs. However, within the 2% or 2 Gy range, the recommended tolerance levels are found to have markedly different effects on the EUDs of the structures of interest.

Early Generation of New PrPSc on Blood Vessels after Brain Microinjection of Scrapie in Mice.

UNLABELLED: Aggregation of misfolded host proteins in the central nervous system is believed to be important in the pathogenic process in several neurodegenerative diseases of humans, including prion diseases, Alzheimer's disease, and Parkinson's disease. In these diseases, protein misfolding and aggregation appear to expand through a process of seeded polymerization. Prion diseases occur in both humans and animals and are experimentally transmissible orally or by injection, thus providing a controllable model of other neurodegenerative protein misfolding diseases. In rodents and ruminants, prion disease has a slow course, lasting months to years. Although prion infectivity has been detected in brain tissue at 3 to 4 weeks postinfection (p.i.), the details of early prion replication in the brain are not well understood. Here we studied the localization and quantitation of PrPSc generation in vivo starting at 30 min postmicroinjection of scrapie into the brain. In C57BL mice at 3 days p.i., generation of new PrPSc was detected by immunohistochemistry and immunoblot assays, and at 7 days p.i., new generation was confirmed by real-time quaking-induced conversion assay. The main site of new PrPSc generation was near the outer basement membrane of small and medium blood vessels. The finding and localization of replication at this site so early after injection have not been reported previously. This predominantly perivascular location suggested that structural components of the blood vessel basement membrane or perivascular astrocytes might act as cofactors in the initial generation of PrPSc. The location of PrPSc replication at the basement membrane also implies a role for the brain interstitial fluid drainage in the early infection process. IMPORTANCE: Neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and prion diseases, of humans are characterized by misfolding and aggregation of certain proteins, resulting in the destruction of brain tissue. In these diseases, the damage process spreads progressively within the central nervous system, but only prion diseases are known to be transmissible between individuals. Here we used microinjection of infectious prion protein (PrPSc) into the mouse brain to model early events of iatrogenic prion transmission via surgical instruments or tissue grafts. At 3 and 7 days postinjection, we detected the generation of new PrPSc, mostly on the outer walls of blood vessels near the injection site. This location and very early replication were surprising and unique. Perivascular prion replication suggested the transport of injected PrPSc via brain interstitial fluid to the basement membranes of blood vessels, where interactions with possible cofactors made by astrocytes or endothelia might facilitate the earliest cycles of prion infection.

Factores de riesgo en el desarrollo de úlceras por presión en pacientes sometidos a cirugía de columna, en un hospital de tercer nivel / Risk factors in the prevention of pressure ulcers in patients undergoing spine surgery, in a third-level hospital

Introducción: las úlceras por presión (UPP) son un problema de salud pública e impacto social, por ello presentamos algunos factores para su prevención en pacientes sometidos a cirugía de columna, en un hospital de tercer nivel. Objetivo: identificar factores de riesgo para el desarrollo de úlceras por presión (UPP) en el agente de cuidado sometido a cirugía de columna en posicionamiento decúbito prono en un hospital de tercer nivel. Material y métodos: estudio cuantitativo, prospectivo y longitudinal, realizado en una institución de tercer nivel, con una n de 20 pacientes. Análisis estadístico descriptivo. Resultados: el porcentaje de género para el estudio fue 50 % para masculino y 50 % para femenino, el predominio de edad fue entre 40 a 59 años con un 60 %, peso y talla representan un factor determinante, las UPP que se desarrollaron con mayor prevalencia en los agentes de cuidado fueron estadio I en un 72% y estadio II en 28%, relacionadas con el tiempo quirúrgico y la presión entre dos planos ejercida durante el procedimiento quirúrgico, por último, los dispositivos terapéuticos representan en el 100% de los casos un factor de riesgo determinante para la aparición de UPP. Conclusión: Es importante que el profesional de enfermería en conjunto con el equipo multidisciplinario del área neuroquirúrgica lleve a cabo las intervenciones de cuidado necesarias para su prevención, pues los factores de riesgo asociados con el desarrollo de UPP son: peso, talla, horas de cirugía y el tipo de superficie de apoyo empleada.