Genetic Ancestry, Race, and Severity of Acutely Decompensated Cirrhosis in Latin America.

BACKGROUND & AIMS: Genetic ancestry or racial differences in health outcomes exist in diseases associated with systemic inflammation (eg, COVID-19). This study aimed to investigate the association of genetic ancestry and race with acute-on-chronic liver failure (ACLF), which is characterized by acute systemic inflammation, multi-organ failure, and high risk of short-term death. METHODS: This prospective cohort study analyzed a comprehensive set of data, including genetic ancestry and race among several others, in 1274 patients with acutely decompensated cirrhosis who were nonelectively admitted to 44 hospitals from 7 Latin American countries. RESULTS: Three hundred ninety-five patients (31.0%) had ACLF of any grade at enrollment. Patients with ACLF had a higher median percentage of Native American genetic ancestry and lower median percentage of European ancestry than patients without ACLF (22.6% vs 12.9% and 53.4% vs 59.6%, respectively). The median percentage of African genetic ancestry was low among patients with ACLF and among those without ACLF. In terms of race, a higher percentage of patients with ACLF than patients without ACLF were Native American and a lower percentage of patients with ACLF than patients without ACLF were European American or African American. In multivariable analyses that adjusted for differences in sociodemographic and clinical characteristics, the odds ratio for ACLF at enrollment was 1.08 (95% CI, 1.03-1.13) with Native American genetic ancestry and 2.57 (95% CI, 1.84-3.58) for Native American race vs European American race CONCLUSIONS: In a large cohort of Latin American patients with acutely decompensated cirrhosis, increasing percentages of Native American ancestry and Native American race were factors independently associated with ACLF at enrollment.

New threats in the recovery of large carnivores inhabiting human-modified landscapes: the case of the Cantabrian brown bear (Ursus arctos).

Understanding mortality causes is important for the conservation of endangered species, especially in small and isolated populations inhabiting anthropized landscapes where both natural and human-caused mortality may hinder the conservation of these species. We investigated the mortality causes of 53 free-ranging brown bears (Ursus arctos) found dead between 1998 and 2023 in the Cantabrian Mountains (northwestern Spain), a highly human-modified region where bears are currently recovering after being critically threatened in the last century. We detected natural traumatic injuries in 52.63% and infectious diseases in 39.47% of the 38 bears for which the mortality causes were registered, with 21.05% of these cases presenting signs of both infectious diseases and traumas. More specifically, almost 30% of the bears died during or after intraspecific fights, including sexually selected infanticide (10.53%). In addition, primary infectious diseases such as infectious canine hepatitis, distemper, clostridiosis and colibacillosis caused the death of 15.79% of the bears. The number of direct human-caused deaths (i.e., shooting, poisoning, snare) decreased over the study period. This study also reveals three new mortality causes triggered by pathogens, two of which-Clostridium novyi and verotoxigenic Escherichia coli-not previously described in ursids, and the other one, canine distemper virus, never reported in brown bears as cause of death. New management strategies for the conservation of Cantabrian bears, which are urgently needed due to the rapid expansion of the population, should consider the mortality causes described in this study and must promote further research to elucidate how the high prevalence of infectious diseases may threaten the current recovery of the population.

Swirling Fluid Reduces the Bounce of Partially Filled Containers.

Certain spatial distributions of water inside partially filled containers can significantly reduce the bounce of the container. In experiments with containers filled to a volume fraction ϕ, we show that rotation offers control and high efficiency in setting such distributions and, consequently, in altering bounce markedly. High-speed imaging evidences the physics of the phenomenon and reveals a rich sequence of fluid-dynamics processes, which we translate into a model that captures our overall experimental findings.

Lifestyle behaviors clusters in a nationwide sample of Spanish children and adolescents: PASOS study.

BACKGROUND: Youth is a vulnerable period. To classify lifestyle behaviors and its relationship with health-related outcomes of Spanish children and adolescents. METHODS: Cross-sectional study including 3261 children aged 7.5-17.5 y (52.8% females). Physical activity (PA), screen-time, sleep time, adherence to Mediterranean diet (MD), weight status (WS) by validated methods. Cluster analysis was run considering chronological age. RESULTS: Six clusters were identified: C1: high screen time, low adherence to MD and sleep time (n = 431,13.20%); C2: high WS, medium adherence to MD,high sleep time, and low screen time (n = 466,14.30%); C3: young group with low screen time and high PA, adherence to MD and sleep (n = 537,16.40%); C4: worst profile regarding adherence to MD, PA, WS and sleep time (n = 609,18.70%); C5: low screen time and PA, high sleep time (n = 804,24.70%); C6: high PA and screen time, low WS (n = 414,12.70%). Mean absolute values were statistically different among PA levels, screen and sleep time, adherence to MD, age, and WS (all p < 0.001). CONCLUSIONS: The most prevalent pattern was low levels of PA, MD, and screen time, and high sleep time. The second most prevalent was characterized by very low levels of PA, sleep time, and adherence to MD, and high screen time, and WS in adolescents. IMPACT STATEMENT: The main identified lifestyle behavior was poor physical activity, low adherence to Mediterranean Diet and high screen and sleep time. Children should increase physical activity levels, adherence to Mediterranean diet, decrease screen and sleep the appropriate hours per day. Families, schools, and medical communities must work together to gloss over present and future diseases. Sleep time had not been previously included in cluster analysis with physical activity, sedentary behaviors, obesity, and nutritional status, thus the present data open a new perspective in Spanish population. Health policies should focus on promoting physical activity, Mediterranean diet, adequate sleep and reducing screen time.

Calcium sulphate biomineralisation: Artefact of sample preparation?

Calcium biomineralisation is widely documented in plants. However, crystallisation of Ca-sulphate-containing minerals is closely related to water content, and sample processing, such as drying, alters the water balance of plant tissues. We hypothesised that common sample processing practices may favour the formation of crystals, leading to spurious crystallisation not observed in unaltered plant tissues. We selected three species (Ononis tridentata, Helianthemum squamatum and Gypsophila struthium) with reported gypsum biomineralisation. We used x-ray diffractometry on fresh intact or sliced leaves, and on the same leaves processed by subsequent drying, to address whether sample processing alters crystal formation. Ca-sulphate crystals were detected in dry samples of all species but not in fresh intact samples. Ca-sulphate crystallisation occurred in some cut fresh samples, although the accumulation greatly increased after drying. In addition, G. struthium exhibited Ca-oxalate crystals in both fresh and dry treatments, with a tendency for greater accumulation in dry treatments. Our results demonstrate that the Ca-sulphate crystals observed by x-ray diffractometry in these species are artefacts caused by common sample processing practices, such as excessive drying and slicing samples. We encourage future studies on the biomineral potential of plants to avoid the use of procedures that alter the water balance of tissues.

Liver decompensation is a frequent cause of treatment discontinuation and prognostic factor in intermediate-advanced HCC.

INTRODUCTION AND OBJECTIVES: With the advent of new therapeutic options for patients with hepatocellular carcinoma (HCC) for intermediate or advanced stages of the Barcelona Clinic Liver Cancer (BCLC), regional real-world data regarding prognostic survival factors are of significant importance. PATIENTS AND METHODS: A multicenter prospective cohort study was conducted in Latin America including BCLC B or C patients since 15th May 2018. We report here the second interim analysis focusing on prognostic variables and causes of treatment discontinuation. Cox proportional hazard survival analysis was performed, estimating hazard ratios (HR) and 95% confidence intervals (95% CI). RESULTS: Overall, 390 patients were included, 55.1% and 44.9% were BCLC B and C at the time of study enrollment. Cirrhosis was present in 89.5% of the cohort. Among the BCLC-B group, 42.3% were treated with TACE with a median survival since the first session of 41.9 months. Liver decompensation before TACE was independently associated with increased mortality [HR 3.22 (CI 1.64;6.33); P<.001]. Systemic treatment was initiated in 48.2% of the cohort (n=188), with a median survival of 15.7 months. Of these, 48.9% presented first-line treatment discontinuation (44.4% tumor progression, 29.3% liver decompensation, 18.5% symptomatic deterioration, and 7.8% intolerance), and only 28.7% received second-line systemic treatments. Liver decompensation [HR 2.9 (1.64;5.29); P<.0001], and symptomatic progression [HR 3.9 (1.53;9.78); P=0.004] were independently associated with mortality after first-line systemic treatment discontinuation. CONCLUSIONS: The complexity of these patients, with one-third presenting liver decompensation after systemic therapies, underlines the need for multidisciplinary team management and the central role of hepatologists.

Simultaneous distributed acoustic sensing and communication over a two-mode fiber.

We designed and tested a distributed acoustic sensing (DAS) that co-exists with optical communication over a two-mode fiber (TMF). In particular, we excited both linearly polarized (LP) modes, LP01 and LP11a, using a photonic lantern for simultaneous information signal transmission while collecting the backscattered Rayleigh light at the near end of the fiber to detect vibrations from a predetermined source. While transmitting data using on-off keying (OOK) or orthogonal frequency-division multiplexing (OFDM) modulation schemes, the optical fiber DAS offers high signal-to-noise ratio (SNR) values that are always larger than the minimum acceptable 2 dB SNR. In addition, as a proof-of-concept experiment, we report parallel sensing and OFDM transmission achieving a data rate of up to 4.2 Gb/s with a bit error rate (BER) of 3.2 × 10-3.

Seroepidemiology of Toxoplasma gondii infection and parasite DNA in free-range chickens in Aguascalientes, Mexico.

The objectives of the study were to estimate the prevalence of anti-Toxoplasma gondii antibodies in free-range chickens in Aguascalientes, Mexico, its association with certain risk factors, and the frequency of parasite DNA in the heart. Eighty-one small rural family farms were included, and blood and heart samples were taken from 150 clinically healthy, adult, free-range chickens. Serum samples were processed by indirect immunofluorescence antibody test considering a dilution of 1:16 as a positive reaction, while the DNA detection was done by PCR. The correlation between the presence of antibodies and the potential risk factors was estimated with logistic regression. The overall seroprevalence in the examined populations was 67%, with a range from 33% to 100% among municipalities, and 78% of the farms having at least one seropositive bird. The PCR test identified the presence of parasite DNA for one case only. Among the variables, the presence of cats and the presence of other animal species on the farm were the ones that had the highest values, while the presence of feral cats and the presence of noxious fauna were also identified as potential risk factors. The results indicate high soil contamination by T. gondii oocysts, which implies the active role of cats living on the farms.

Validity, reliability, and calibration of the physical activity unit 7 item screener (PAU-7S) at population scale.

BACKGROUND: Validation of self-reported tools, such as physical activity (PA) questionnaires, is crucial. The aim of this study was to determine test-retest reliability, internal consistency, and the concurrent, construct, and predictive validity of the short semi-quantitative Physical Activity Unit 7 item Screener (PAU-7S), using accelerometry as the reference measurement. The effect of linear calibration on PAU-7S validity was tested. METHODS: A randomized sample of 321 healthy children aged 8-16 years (149 boys, 172 girls) from the nationwide representative PASOS study completed the PAU-7S before and after wearing an accelerometer for at least 7 consecutive days. Weight, height, and waist circumference were measured. Cronbach alpha was calculated for internal consistency. Test-retest reliability was determined by intra-class correlation (ICC). Concurrent validity was assessed by ICC and Spearman correlation coefficient between moderate to vigorous PA (MVPA) derived by the PAU-7S and by accelerometer. Concordance between both methods was analyzed by absolute agreement, weighted kappa, and Bland-Altman statistics. Multiple linear regression models were fitted for construct validity and predictive validity was determined by leave-one-out cross-validation. RESULTS: The PAU-7S overestimated MVPA by 18%, compared to accelerometers (106.5 ± 77.0 vs 95.2 ± 33.2 min/day, respectively). A Cronbach alpha of 0.76 showed an acceptable internal consistency of the PAU-7S. Test-retest reliability was good (ICC 0.71 p < 0.001). Spearman correlation and ICC coefficients of MVPA derived by the PAU-7S and accelerometers increased from 0.31 to 0.62 and 0.20 to 0.62, respectively, after calibration of the PAU-7S. Between-methods concordance improved from a weighted kappa of 0.24 to 0.50 after calibration. A slight reduction in ICC, from 0.62 to 0.60, yielded good predictive validity. Multiple linear regression models showed an inverse association of MVPA with standardized body mass index (ß - 0.162; p < 0.077) and waist to height ratio (ß - 0.010; p < 0.014). All validity dimensions were somewhat stronger in boys compared to girls. CONCLUSION: The PAU-7S shows a good test-retest reliability and acceptable internal consistency. All dimensions of validity increased from poor/fair to moderate/good after calibration. The PAU-7S is a valid instrument for measuring MVPA in children and adolescents. TRIAL REGISTRATION: Trial registration number ISRCTN34251612 .

A modified Delphi consensus study to identify improvement proposals for COPD management amongst clinicians and administrators in Spain.

AIMS: To identify the obstacles hindering the appropriate management of chronic obstructive pulmonary disease (COPD) in Spain based on consensus amongst clinicians and administrators. METHODS: A two-round modified Delphi questionnaire was sent to clinicians (pulmonologists and GPs) and administrators, all experts in COPD. The scientific committee developed the statements and selected the participating experts. Four areas were explored: diagnosis, training, treatment, and clinical management. Panellists' agreement was assessed using a 9-point Likert scale, with scores of 1 to 3 indicating disagreement and 7 to 9, agreement. Consensus was considered to exist when 70% of the participants agreed or disagreed with the statement. RESULTS: Respective response rates for the first and second round were 68% and 91% for clinicians, and 60% and 100% for administrators. The statements attracting the highest degree of consensus were: "Not enough nursing resources (time, staff, duties) are allocated for performing spirometry" (85.3% clinicians; 75% administrators); "Nurses need specific training in COPD" (84.8% clinicians; 100% administrators); "Rehabilitation programs are necessary for treating patients with COPD" (94.1% clinicians; 91.7% administrators); and "Integrated care processes facilitate the deployment of educational programs on COPD" (79.4% clinicians; 83.3% administrators). CONCLUSIONS: This document can inform the development and implementation of specific initiatives addressing the existing obstacles in COPD management. WHAT'S KNOWN: COPD is a prevalent and underdiagnosed disease that causes substantial morbidity and mortality. The National COPD Strategy established objectives and work programmes to apply in Spain. There are barriers impeding the application of interventions contemplated in the COPD strategy. WHAT'S NEW: Different agents involved in COPD management agree that the main challenges to improve COPD management are resource shortages in primary care nursing and lack of training in the use of COPD clinical guidelines. Clinicians and administrators involved in COPD management support the implementation of urgent measures to tackle the underdiagnosis of COPD, especially in primary care, along with the routine inclusion of respiratory rehabilitation programmes for COPD.

Incidence of Huntington disease in a northeastern Spanish region: a 13-year retrospective study at tertiary care centre.

BACKGROUND: Despite the progress in the knowledge of Huntington disease (HD) in recent years, the epidemiology continues uncertain, so the study of incidence becomes relevant. This is important since various factors (type of population, diagnostic criteria, disease-modifying factors, etc.) make these data highly variable. Therefore, the genetic diagnosis of these patients is important, since it unequivocally allows the detection of new cases. METHODS: Descriptive retrospective study with 179 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per 100,000 inhabitants per year during the period 2007-2019 in Aragon (Spain). RESULTS: 50 (27.9%) incident cases of HD (CAG repeat length ≥ 36) were identified from a total of 179 persons studied. The remaining 129/179 (72.1%) were HD negative (CAG repeat length < 36). 29 (58.0%) females and 21 (42.0%) males were confirmed as HD cases. The overall incidence was 0.648 per 100,000 patient-years. 11/50 positive HD cases (22.0%) were identified by performing a predictive test, without clinical symptoms. The minimum number of CAG repeats found was 9 and the most common CAG length among HD negative individuals was 16. CONCLUSIONS: Our incidence lied within the range reported for other Caucasian populations. Implementation of new techniques has allowed to determine the exact number of CAG repeats, which is especially important in patients with triplet expansions in an HD intermediate and/or incomplete penetrance allele, both in diagnostic, predictive and prenatal tests.

International and multicenter real-world study of sorafenib-treated patients with hepatocellular carcinoma under dialysis.

BACKGROUND & AIMS: Information on safety and efficacy of systemic treatment in patients with hepatocellular carcinoma (HCC) under dialysis are limited due to patient exclusion from clinical trials. Thus, we aimed to evaluate the rate, prevalence, tolerability, and outcome of sorafenib in this population. METHODS: We report a multicenter study comprising patients from Latin America and Europe. Patients treated with sorafenib were enrolled; demographics, dose modifications, adverse events (AEs), treatment duration, and outcome of patients undergoing dialysis were recorded. RESULTS: As of March 2018, 6156 HCC patients were treated in 44 centres and 22 patients were concomitantly under dialysis (0.36%). The median age was 65.5 years, 40.9% had hepatitis C, 75% had Child-Pugh A, and 85% were Barcelona Clinic Liver Cancer-C. The median time to first dose modification, treatment duration and overall survival rate were 2.4 months (interquartile ranges [IQR], 0.8-3.8), 10.8 months (IQR, 4.5-16.9), and 17.5 months (95% CI, 7.2-24.5), respectively. Seventeen patients required at least 1 dose modification. The main causes of first dose modification were asthenia/worsening of Eastern Cooperative Oncology Group-Performance Status and diarrhoea. At the time of death or last follow-up, four patients were still on treatment and 18 had discontinued sorafenib: 14 were due to tumour progression, 2 were sorafenib-related, and 2 were non-sorafenib-related AE. CONCLUSIONS: The outcomes observed in this cohort seem comparable to those in the non-dialysis population. Thus, to the best of our knowledge, this is the largest and most informative dataset regarding systemic treatment outcomes in HCC patients undergoing dialysis.

Stability of bubble-like fluxons in disk-shaped Josephson junctions in the presence of a coaxial dipole current.

We investigate analytically and numerically the stability of bubble-like fluxons in disk-shaped heterogeneous Josephson junctions. Using ring solitons as a model of bubble fluxons in the two-dimensional sine-Gordon equation, we show that the insertion of coaxial dipole currents prevents their collapse. We characterize the onset of instability by introducing a single parameter that couples the radius of the bubble fluxon with the properties of the injected current. For different combinations of parameters, we report the formation of stable oscillating bubbles, the emergence of internal modes, and bubble breakup due to internal mode instability. We show that the critical germ depends on the ratio between its radius and the steepness of the wall separating the different phases in the system. If the steepness of the wall is increased (decreased), the critical radius decreases (increases). Our theoretical findings are in good agreement with numerical simulations.

First outbreak of bovine haemorrhagic septicaemia caused by Pasteurella multocida type B in Spain - Short communication.

This paper describes the first documented outbreak of haemorrhagic septicaemia (HS) caused by Pasteurella multocida type B in cattle in Spain. This acute, highly fatal septicaemia causes major economic losses in cattle and buffaloes in many areas of Asia and Africa. In other species and in European countries it is an infrequently reported disease. Acute septicaemic pasteurellosis occurred in a free-range farm of 150 cattle and 70 beef calves in Southern Spain. Twenty-one calves and one cow were affected, of which three calves and the adult cow died. Postmortem examination revealed characteristic oedema in the ventral area of the neck and the brisket region, and widespread haemorrhages in all organs. Pure cultures of P. multocida were obtained from all tissues and organs studied. The aetiological agent was further confirmed by molecular and biochemical analysis as P. multocida capsular type B, biovar 3. Although the source of infection could not be determined, wildlife may play an important role. The use of tulathromycin in the initial stage of the disease might be related to the low morbidity and mortality of this outbreak. After using an autogenous vaccine no more cases of HS were observed.

Isotemporal substitution of inactive time with physical activity and time in bed: cross-sectional associations with cardiometabolic health in the PREDIMED-Plus study.

BACKGROUND: This study explored the association between inactive time and measures of adiposity, clinical parameters, obesity, type 2 diabetes and metabolic syndrome components. It further examined the impact of reallocating inactive time to time in bed, light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) on cardio-metabolic risk factors, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. METHODS: This is a cross-sectional analysis of baseline data from 2189 Caucasian men and women (age 55-75 years, BMI 27-40 Kg/m2) from the PREDIMED-Plus study (http://www.predimedplus.com/). All participants had ≥3 components of the metabolic syndrome. Inactive time, physical activity and time in bed were objectively determined using triaxial accelerometers GENEActiv during 7 days (ActivInsights Ltd., Kimbolton, United Kingdom). Multiple adjusted linear and logistic regression models were used. Isotemporal substitution regression modelling was performed to assess the relationship of replacing the amount of time spent in one activity for another, on each outcome, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. RESULTS: Inactive time was associated with indicators of obesity and the metabolic syndrome. Reallocating 30 min per day of inactive time to 30 min per day of time in bed was associated with lower BMI, waist circumference and glycated hemoglobin (HbA1c) (all p-values < 0.05). Reallocating 30 min per day of inactive time with 30 min per day of LPA or MVPA was associated with lower BMI, waist circumference, total fat, visceral adipose tissue, HbA1c, glucose, triglycerides, and higher body muscle mass and HDL cholesterol (all p-values < 0.05). CONCLUSIONS: Inactive time was associated with a poor cardio-metabolic profile. Isotemporal substitution of inactive time with MVPA and LPA or time in bed could have beneficial impact on cardio-metabolic health. TRIAL REGISTRATION: The trial was registered at the International Standard Randomized Controlled Trial (ISRCTN: http://www.isrctn.com/ISRCTN89898870) with number 89898870 and registration date of 24 July 2014, retrospectively registered.

An Integrative Screening Tool of Alcohol Exposure During Early Pregnancy: Combining of the CDT Biomarker with Green Page Questionnaire.

AIMS: In current clinical practice, prenatal alcohol exposure is usually assessed by interviewing the pregnant woman by applying questionnaires. An alternative method for detecting alcohol use is to measure the biomarker carbohydrate-deficient transferrin (CDT). However, few studies measure CDT during pregnancy. This study examines the utility of CDT biomarker in the screening of alcohol exposure during early pregnancy. METHODS: A cohort of 91, first-trimester pregnant women assigned to a public reference maternity hospital, was screened using the Green Page (GP) questionnaire, an environmental exposure tool. CDT levels and other biomarkers of alcohol use were measured and compared with questionnaire data. RESULTS: About 70% of the mothers in the study consumed alcohol during early pregnancy and 22% met high-risk criteria for prenatal exposure to alcohol. CDT measurement showed a statistically significant area under the receiver operating characteristic curve with a value of 0.70. For a value of 0.95% of CDT, a specificity of 93% was observed. The most significant predictors of CDT were the number of binge drinking episodes, women's body mass index and European white race. CONCLUSION: Pregnant women with a CDT value >0.95% would be good candidates for the performance of the GP questionnaire during early pregnancy in order to detect potential high-risk pregnancy due to alcohol exposure.

Colombian experience in the treatment of hepatitis C with direct-acting antiviral agents.

There are few published real-world studies on hepatitis C in Latin America. This paper describes a cohort of Colombian subjects treated with direct-acting antiviral agents. A total of 195 patients from 5 hepatology centers in 4 Colombian cities were retrospectively studied. For each patient, serum biomarkers were obtained, and Child-Pugh, MELD, cirrhosis and fibrosis stage were calculated. Additionally, viral load was quantified at initiation, end of treatment and at 12 weeks of completion. Adverse effects were recorded. Patients with liver transplant were compared with non-transplanted patients in terms of serum biomarkers. The patients had received 9 different regimes. The most prevalent viral genotype was 1b (81.5%). Overall, 186 patients (95.4%) attained sustained virologic response. When comparing transplanted vs. non-transplanted patients, those in the non-transplanted group were more likely to have cirrhosis (52.6% vs. 12.5%, p = 0.0004). Pre-treatment viral load was higher in the transplant group (1 743 575 IQR = 1 038 062-4 252 719 vs. 345 769 IQR = 125 806-842 239; p < 0.0001) as well as ALT and AST levels (82.5 IQR 43.5-115.5 vs. 37.0 IQR = 24.7-73.3; p = 0.0009 and 70 IQR = 41-140 vs. 37 IQR = 24-68; p = 0.004 respectively). Adverse events were reported by 28.7% of the patients; asthenia (5.6%) was the most prevalent. Our results are comparable with those from other countries in terms of therapy and biomarkers. However, our cohort reported less adverse events. Further research is needed in the region.

A perfusion chamber for monitoring transepithelial NaCl transport in an in vitro model of the renal tubule.

Transepithelial electrical measurements in the renal tubule have provided a better understanding of how kidney regulates electrolyte and water homeostasis through the reabsorption of molecules and ions (e.g., H2 O and NaCl). While experiments and measurement techniques using native tissue are difficult to prepare and to reproduce, cell cultures conducted largely with the Ussing chamber lack the effect of fluid shear stress which is a key physiological stimulus in the renal tubule. To overcome these limitations, we present a modular perfusion chamber for long-term culture of renal epithelial cells under flow that allows the continuous and simultaneous monitoring of both transepithelial electrical parameters and transepithelial NaCl transport. The latter is obtained from electrical conductivity measurements since Na+ and Cl- are the ions that contribute most to the electrical conductivity of a standard physiological solution. The system was validated with epithelial monolayers of raTAL and NRK-52E cells that were characterized electrophysiologically for 5 days under different flow conditions (i.e., apical perfusion, basal, or both). In addition, apical to basal chemical gradients of NaCl (140/70 and 70/140 mM) were imposed in order to demonstrate the feasibility of this methodology for quantifying and monitoring in real time the transepithelial reabsorption of NaCl, which is a primary function of the renal tubule.

Immunohistochemical characterization of tuberculous lesions in sheep naturally infected with Mycobacterium bovis.

BACKGROUND: Sheep have been traditionally considered as less susceptible to Mycobacterium bovis (Mbovis) infection than other domestic ruminants such as cattle and goats. However, there is increasing evidence for the role of this species as a domestic Mbovis reservoir, mostly when sheep share grazing fields with infected cattle and goats. Nevertheless, there is a lack of information about the pathogenesis and the immune response of Mbovis infection in sheep. The goals of this study were to characterize the granuloma stages produced by the natural infection of Mbovis in sheep, to compare them with other species and to identify possible differences in the sheep immune response. Samples from bronchial lymph nodes from twelve Mbovis-naturally infected sheep were used. Four immunohistochemical protocols for the specific detection of T-lymphocytes, B-lymphocytes, plasma cells and macrophages were performed to study the local immune reaction within the granulomas. RESULTS: Differences were observed in the predominant cell type present in each type of granuloma, as well as differences and similarities with the development of tuberculous granulomas in other species. Very low numbers of T-lymphocytes were observed in all granuloma types indicating that specific cellular immune response mediated by T-cells might not be of much importance in sheep in the early stages of infection, when macrophages are the predominant cell type within lesions. Plasma cells and mainly B lymphocytes increased considerably as the granuloma developed being attracted to the lesions in a shift towards a Th2 response against the increasing amounts of mycobacteria. Therefore, we have proposed that the granulomas could be defined as initial, developed and terminal. CONCLUSIONS: Results showed that the study of the lymphoid tissue granulomata reinforces the view that the three different types of granuloma represent stages of lesion progression and suggest an explanation to the higher resistance of sheep based on a higher effective innate immune response to control tuberculosis infection.