Identifying Biases in a Multicenter MRI Database for Parkinson's Disease Classification: Is the Disease Classifier a Secret Site Classifier?

Sharing multicenter imaging datasets can be advantageous to increase data diversity and size but may lead to spurious correlations between site-related biological and non-biological image features and target labels, which machine learning (ML) models may exploit as shortcuts. To date, studies analyzing how and if deep learning models may use such effects as a shortcut are scarce. Thus, the aim of this work was to investigate if site-related effects are encoded in the feature space of an established deep learning model designed for Parkinson's disease (PD) classification based on T1-weighted MRI datasets. Therefore, all layers of the PD classifier were frozen, except for the last layer of the network, which was replaced by a linear layer that was exclusively re-trained to predict three potential bias types (biological sex, scanner type, and originating site). Our findings based on a large database consisting of 1880 MRI scans collected across 41 centers show that the feature space of the established PD model (74% accuracy) can be used to classify sex (75% accuracy), scanner type (79% accuracy), and site location (71% accuracy) with high accuracies despite this information never being explicitly provided to the PD model during original training. Overall, the results of this study suggest that trained image-based classifiers may use unwanted shortcuts that are not meaningful for the actual clinical task at hand. This finding may explain why many image-based deep learning models do not perform well when applied to data from centers not contributing to the training set.

A multi-center distributed learning approach for Parkinson's disease classification using the traveling model paradigm

Distributed learning is a promising alternative to central learning for machine learning (ML) model training, overcoming data-sharing problems in healthcare. Previous studies exploring federated learning (FL) or the traveling model (TM) setup for medical image-based disease classification often relied on large databases with a limited number of centers or simulated artificial centers, raising doubts about real-world applicability. This study develops and evaluates a convolution neural network (CNN) for Parkinson's disease classification using data acquired by 83 diverse real centers around the world, mostly contributing small training samples. Our approach specifically makes use of the TM setup, which has proven effective in scenarios with limited data availability but has never been used for image-based disease classification. Our findings reveal that TM is effective for training CNN models, even in complex real-world scenarios with variable data distributions. After sufficient training cycles, the TM-trained CNN matches or slightly surpasses the performance of the centrally trained counterpart (AUROC of 83% vs. 80%). Our study highlights, for the first time, the effectiveness of TM in 3D medical image classification, especially in scenarios with limited training samples and heterogeneous distributed data. These insights are relevant for situations where ML models are supposed to be trained using data from small or remote medical centers, and rare diseases with sparse cases. The simplicity of this approach enables a broad application to many deep learning tasks, enhancing its clinical utility across various contexts and medical facilities.

Image-encoded biological and non-biological variables may be used as shortcuts in deep learning models trained on multisite neuroimaging data

OBJECTIVE

This work investigates if deep learning (DL) models can classify originating site locations directly from magnetic resonance imaging (MRI) scans with and without correction for intensity differences.

MATERIAL AND METHODS

A large database of 1880 T1-weighted MRI scans collected across 41 sites originally for Parkinson's disease (PD) classification was used to classify sites in this study. Forty-six percent of the datasets are from PD patients, while 54% are from healthy participants. After preprocessing the T1-weighted scans, 2 additional data types were generated: intensity-harmonized T1-weighted scans and log-Jacobian deformation maps resulting from nonlinear atlas registration. Corresponding DL models were trained to classify sites for each data type. Additionally, logistic regression models were used to investigate the contribution of biological (age, sex, disease status) and non-biological (scanner type) variables to the models' decision.

RESULTS

A comparison of the 3 different types of data revealed that DL models trained using T1-weighted and intensity-harmonized T1-weighted scans can classify sites with an accuracy of 85%, while the model using log-Jacobian deformation maps achieved a site classification accuracy of 54%. Disease status and scanner type were found to be significant confounders.

DISCUSSION

Our results demonstrate that MRI scans encode relevant site-specific information that models could use as shortcuts that cannot be removed using simple intensity harmonization methods.

CONCLUSION

The ability of DL models to exploit site-specific biases as shortcuts raises concerns about their reliability, generalization, and deployability in clinical settings.

Explainable classification of Parkinson's disease using deep learning trained on a large multi-center database of T1-weighted MRI datasets

INTRODUCTION

Parkinson's disease (PD) is a severe neurodegenerative disease that affects millions of people. Early diagnosis is important to facilitate prompt interventions to slow down disease progression. However, accurate PD diagnosis can be challenging, especially in the early disease stages. The aim of this work was to develop and evaluate a robust explainable deep learning model for PD classification trained from one of the largest collections of T1-weighted magnetic resonance imaging datasets.

MATERIALS AND METHODS

A total of 2,041 T1-weighted MRI datasets from 13 different studies were collected, including 1,024 datasets from PD patients and 1,017 datasets from age- and sex-matched healthy controls (HC). The datasets were skull stripped, resampled to isotropic resolution, bias field corrected, and non-linearly registered to the MNI PD25 atlas. The Jacobian maps derived from the deformation fields together with basic clinical parameters were used to train a state-of-the-art convolutional neural network (CNN) to classify PD and HC subjects. Saliency maps were generated to display the brain regions contributing the most to the classification task as a means of explainable artificial intelligence.

RESULTS

The CNN model was trained using an 85%/5%/10% train/validation/test split stratified by diagnosis, sex, and study. The model achieved an accuracy of 79.3%, precision of 80.2%, specificity of 81.3%, sensitivity of 77.7%, and AUC-ROC of 0.87 on the test set while performing similarly on an independent test set. Saliency maps computed for the test set data highlighted frontotemporal regions, the orbital-frontal cortex, and multiple deep gray matter structures as most important.

CONCLUSION

The developed CNN model, trained on a large heterogenous database, was able to differentiate PD patients from HC subjects with high accuracy with clinically feasible classification explanations. Future research should aim to investigate the combination of multiple imaging modalities with deep learning and on validating these results in a prospective trial as a clinical decision support system.

An analysis of the effects of limited training data in distributed learning scenarios for brain age prediction

OBJECTIVE

Distributed learning avoids problems associated with central data collection by training models locally at each site. This can be achieved by federated learning (FL) aggregating multiple models that were trained in parallel or training a single model visiting sites sequentially, the traveling model (TM). While both approaches have been applied to medical imaging tasks, their performance in limited local data scenarios remains unknown. In this study, we specifically analyze FL and TM performances when very small sample sizes are available per site.

MATERIALS AND METHODS

2025 T1-weighted magnetic resonance imaging scans were used to investigate the effect of sample sizes on FL and TM for brain age prediction. We evaluated models across 18 scenarios varying the number of samples per site (1, 2, 5, 10, and 20) and the number of training rounds (20, 40, and 200).

RESULTS

Our results demonstrate that the TM outperforms FL, for every sample size examined. In the extreme case when each site provided only one sample, FL achieved a mean absolute error (MAE) of 18.9 ± 0.13 years, while the TM achieved a MAE of 6.21 ± 0.50 years, comparable to central learning (MAE = 5.99 years).

DISCUSSION

Although FL is more commonly used, our study demonstrates that TM is the best implementation for small sample sizes.

CONCLUSION

The TM offers new opportunities to apply machine learning models in rare diseases and pediatric research but also allows even small hospitals to contribute small datasets.

P-120 Microfluidic sperm selection device increases clinical pregnancy rate in IVF/ PGT-A cycles

Study question

Evaluate the influence of sperm selection according to the sorting technique, and its effects in clinical and laboratory parameters in IVF/PGT-A cycles.

Summary answer

Cycles that used microfluidic sperm selection device presented an increase in clinical pregnancy rates.

What is known already

A common genomic anomaly detected in subfertile men is the Sperm DNA fragmentation. It is resulted of a high concentation of free radicals produced causing oxidative stress in sperm cells. In order to achieve a normal embryonic development is necessary good spermatozoa with intact genetic material. In fact, embryonic quality parameters as lower fertilization, blastocyst formation and pregnancy rates has been related with Sperm DNA fragmentation increased cases. The microfluidic sperm selection device has been commercialized promising to select spermatozoa with a low level of DNA fragmentation and suggest a relationship between embryo quality, euploidy and pregnancy rates.

Study design, size, duration

A case-control study involving 494 IVF/PGT-A cycles that resulted in embryo biopsy between June, 2020 and November, 2021 at a Brazilian private practice unit (Instituto Ideia Fertil) were included in this analysis.

Participants/materials, setting, methods

All cycles that would perform PGT-A were splitted in two groups considering the sperm sorting technique: case - Microfluidic sperm selection device (245 cycles) and control - Density gradient centrifugation + swim-up (249 cycles) were included. The variables considered in this analysis were patient age, sperm concentration, fertilization, D3 top quality, blastocyst top quality, blastulation, ploidy and pregnancy rates. This data were analysed between groups and female age (until 37; 38-40 and over 41).

Main results and the role of chance

The mean age of the female and male patients found were 38.05 and 38.2 respectively and there was not statistically significant different between groups. Fertilization rate compared between case (72.4%) and control (76.5%) groups (p < 0.05) demonstrated statistically significant difference, but when stratified accordingly to the age, only the female age until 37 years old group showed significant difference (73.25%; 76.43%; p < 0.05). The variables analyzed as D3 Top Quality, Blastocyst Top Quality, blastulation and ploidy did not present difference (p = 0.552; 0.699; 0.378). The clinical pregnancy rate analyzed revealed in case group 65.33% and control 56.38% (p < 0.05), demonstrating statistically significant difference. When groups were splitted according to the female age (until 37 years old; 38-40 and over 41) the findings behaved in the same characteristics, increasing only the clinical pregnancy rate. The tests used was Mann-Whitney and Kruskal-wallis.

Limitations, reasons for caution

The DNA fragmentation test was not evaluated because not all patients had this test performed. Besides that, another parameter that will be analysed is live birth rate.

Wider implications of the findings

Microfluidic sperm sorting device made possible to select high quality spermatozoa according to motility, morphology, and low rates of fragmentation, showing the importance of having a good sperm in clinical pregnancy rate.

Trial registration number

none

Constructing evidence-based clinical intrapartum care algorithms for decision-support tools

AIM

To describe standardised iterative methods used by a multidisciplinary group to develop evidence-based clinical intrapartum care algorithms for the management of uneventful and complicated labours.

POPULATION

Singleton, term pregnancies considered to be at low risk of developing complications at admission to the birthing facility.

SETTING

Health facilities in low- and middle-income countries.

SEARCH STRATEGY

Literature reviews were conducted to identify standardised methods for algorithm development and examples from other fields, and evidence and guidelines for intrapartum care. Searches for different algorithm topics were last updated between January and October 2020 and included a combination of terms such as 'labour', 'intrapartum', 'algorithms' and specific topic terms, using Cochrane Library and MEDLINE/PubMED, CINAHL, National Guidelines Clearinghouse and Google.

CASE SCENARIOS

Nine algorithm topics were identified for monitoring and management of uncomplicated labour and childbirth, identification and management of abnormalities of fetal heart rate, liquor, uterine contractions, labour progress, maternal pulse and blood pressure, temperature, urine and complicated third stage of labour. Each topic included between two and four case scenarios covering most common deviations, severity of related complications or critical clinical outcomes.

CONCLUSIONS

Intrapartum care algorithms provide a framework for monitoring women, and identifying and managing complications during labour and childbirth. These algorithms will support implementation of WHO recommendations and facilitate the development by stakeholders of evidence-based, up to date, paper-based or digital reminders and decision-support tools. The algorithms need to be field tested and may need to be adapted to specific contexts.

TWEETABLE ABSTRACT

Evidence-based intrapartum care clinical algorithms for a safe and positive childbirth experience.

B-lines by lung ultrasound is associated with pulmonary symptoms and cardiac function in acute malaria: a prospective cohort study

Background

Malaria patients are at risk of cardiopulmonary complications, but diagnosis and management are difficult in resource limited environments. B-lines by lung ultrasonography (LUS) can identify pulmonary alterations, however, little is known about the usefulness in malaria.

Purpose

We aimed to investigate the occurrence of B-lines in acute malaria patients at baseline and at follow-up, and whether they are associated with shortness of breath and impaired left ventricular ejection fraction (LVEF).

Methods

Adult patients with non-severe acute malaria were prospectively enrolled from June to December 2020 in community healthcare clinics in a remote area. Patients were age- and sex-matched to controls without a prior history of malaria. We examined patients prior to anti-malaria treatment and at follow-up. Malaria treatment was administered according to national guidelines. Patients were excluded if they were pregnant, had concomitant infections or recent chest trauma. Patients underwent LUS (8-zones), echocardiography and peripheral blood smear. Measurements were blinded to clinical variables and outcomes.

Results

We included a total of 99 patients (median age 40±15 years, 55% men). Patients suffered from Plasmodium vivax (n=75), P. falciparum (n=22), and a mix of the two (n=2) and median parasite density was 1,595 parasites/mL (interquartile range [IQR] 528–6,585/mL). Follow-up was completed in 71 patients and the median follow-up time was 31 days (IQR 27–40 days).

Patients with acute malaria had significantly more B-lines at baseline than matched controls (P-value<0.001) and fewer B-lines at follow-up (P-value<0.001) (Figure 1). In acute malaria patients, number of B-lines at baseline correlated significantly with shortness of breath (OR 1.20, [1.04 to 1.39], P-value=0.01) and with LVEF (adjusted for age and sex: +8% [+1% to +15%], P-value=0.016 per 1% decrease in LVEF). There was no correlation between number of B-lines and parasite density (+2% [−5% to +11%], P-value=0.53 per 1000 increase in parasite density).

Conclusion

B-lines detected by LUS are more frequent in patients with acute malaria than in age- and sex-matched controls and decrease in response to treatment. B-lines also correlate with shortness of breath and lower LVEF at baseline. Because LUS is a quick and accessible examination, it may potentially facilitate risk stratification and therapeutic decisions regarding cardiopulmonary complications in patients with acute malaria.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Danish Heart Association

Continuing Education in Health: interprofessional practices in the field of Collective Health

Family Health Support Centres (NASFs, in Portuguese) aim to develop interprofessional practices anchored in the assumptions of Primary Health Care, guided by the criteria of shared care specific professional interventions, management processes, interdisciplinarity, intersectoriality, Continuing Education in Health and health promotion. This health management methodology (Matrix Support) still represents a challenge to workers and managers, as it switches the logic of clinical thought from individual-centred, ambulatory and disciplinary care to collective, territory and interdisciplinary care. This study might illustrate and allow sharing of experiences about a work management format for multidisciplinary teams in Primary Health Care. A partnership between the University and the state health department was established in order to elaborate a collaborative, educational and supportive action. We formed a group of workers in the target area (24 municipalities and 18 teams) who had a focus on Continuing Education in Health using Institutional Analysis as theoretical reference. The main goal of the action was to provide spaces to share experiences and learning in the perspective of Continuing Education in Health. How does Continuing Education in Health support interprofessional practices in the field of Collective Health? Among the main results, we list: reflection about organisation practices of multiprofessional work, reflection about care practices and clinic management in the technical-assistance and pedagogic perspectives of Matrix Support; encouragement to improve the services offered in this level of care and their relationship with other points of the network. This experience showed us the importance of three main aspects: Continuing Education in Health, as a strategy of critical analysis about work and workers; the partnership and integration between teaching and service; and interprofessional formation processes (necessary to NASF and Collective Health).

Key messages

Continuing Education in Health is a strategy to deal with challenges and possibilities of interprofessional practices in the field of Collective Health. Enabling experiences and providing spaces for health professionals to share experience and learning.

Chronic thromboembolic and pulmonary arterial hypertension share right ventricular and pulmonary artery CMR features

BACKGROUND

Cardiac magnetic resonance (CMR) imaging has gained importance in pulmonary hypertension (PH) and studies have demonstrated its use as a surrogate marker and in following treatment of these patients. The pathophysiology of PH differs between pulmonary arterial hypertension (PAH, group 1) and chronic thromboembolic PH (CTEPH, group 4).

OBJECTIVES

The present study tested the hypothesis that PAH and CTEPH display different characteristics on CMR imaging.

METHODS

46 patients were evaluated for pulmonary vascular disease in the French National Reference Center for PH (23 PAH and 23 CTEPH matched for age and gender). All patients had the right heart catheterization (RHC) and CMR imaging performed within 48h. CMR imaging was performed on a 1.5 T scanner.

RESULTS

PAH and CTEPH had similar body surface area and similar invasive hemodynamics, including mean pulmonary arterial pressure, cardiac index, pulmonary vascular resistance and right atrial pressure. PAH and CTEPH had similar CMR data. Right ventricular (RV) morphology and function and pulmonary artery (PA) data were also similar.

CONCLUSION

Age- and sex-matched PAH and CTEPH patients displayed similar values of the CMR indices of RV and PA morphology and function, suggesting that the RV-PA responses are similar in both groups, mostly related to the overall increase in after load.

Critical analysis of aortic dysmorphism in Marfan Syndrome

Introduction: Marfan syndrome (OMIM #154700) was described for the first time in 1896 by Antoine Bernard-Jean Marfan. It is characterized by its autosomal dominant inheritance pattern, affects 1:5000 of those born alive, and involves the gene that codifies the structural protein fribrillin-1. Fibrillin-1 is critical for the formation of the elastic system backbone and for the negative regulation of the cytokine transforming growth factor beta 1 (TGF-β1). In the syndrome this fibrillar component causes the degeneration of the fibers of the elastic system, which no longer sequesters matrix TGF-β, causing disorganization of the collagen fibers and vascular smooth muscles. The disease affects mainly the cardiovascular system, cardiovascular problems being the main cause of death. This is because arteries have large amounts of elastic fibers that rupture in an adverse process, causing mainly dissections and aneurisms, which have been better clariied in experimental studies with mice. Objective: The objective of this study was to conduct an etiopathogenic and molecular review to describe the advances in the understanding of blood vessel dysmorphism in the syndrome, especially of the aorta. Materials and Methods: For this purpose the literature of the last 35 years was extensively reviewed. Conclusion: The origin of the aortic dysmorphism in the syndrome stems from a number of events that begin with the mutation of the gene fibrillin-1, causing fragmentation of the aortic elastic fibers. Excess cytokine TGF-β increases the amount of metalloproteinases and of vascular smooth muscle cell apoptosis, leading to matrix remodeling and increasing the susceptibility of the vessel to an aneurysm or dissecting process.

Ultrathin Monolithic Zirconia Veneers: Reality or Future? Report of a Clinical Case and One-year Follow-up

Yttria-stabilized polycrystalline zirconia ceramics have greatly advanced over the past few years. High-translucent zirconia is a newly introduced ceramic that affords high strength and esthetics and that has significantly increased the clinical indications of monolithic zirconia restorations. Thus, the purpose of this case report was to evaluate the performance of ultrathin monolithic zirconia veneers adhesively luted to enamel surfaces after minimally invasive preparations; in addition, we aimed at presenting a clinical protocol for zirconia surface treatment in order to promote bonding effectiveness to resin cement. This type of restoration presented very acceptable esthetic results and decreased the risk of fracturing the veneer during try-in and clinical use. The results were still satisfactory after one-year follow-up. However, randomized, prospective, controlled clinical trials are required to determine the long-term clinical durability of this treatment.

Electromyographic study on the sternocleidomastoid and pectoralis major muscles during respiratory activity in humans

Introduction: This study aimed to evaluate the simultaneous and maximum activities ofthe sternocleidomastoid (SCM) and pectoralis major (PM) muscles, to determine how the two types of breathing patterns (normal and forced) can affect these activities , and to verify which of these muscles could be used to establish an evaluation protocol for patients undergoing mechanical ventilation. Methods: Eleven healthy men, aged 18 to 25 years, participated in this study. The individuals remained in supine position using a respiratory belt to monitor both inspiratory and expiratory phase during shifts in the rib cage, performing three repetitions for the normal and forced respiratory movements, while keeping the breathing rhythm with a standard metronome. Electromyographic signals were captured using bipolar surface electrodes placed on the lower third of the SCM muscle and on the lower PM muscle fibers. Electromyographic signals were analyzed and the root mean square (RMS) values were calculated for a complete respiratory cycle. The EMG values were analyzed using the Bonferroni test for multiple comparisons. The homogeneity of variances was verified using the logarithmic transformation (LOG). The level of statistical significance was set at 5% (SPSS 19.0). Results: The values showed that there are signiicant differences between the EMG values of the SCM muscle during normal and forced respiration and the EMG values of the ECM and PM muscles during forced respiration. Conclusion: These results showed that the SCM muscle can be an indicator for the development of parameters to be used in the analysis of patients with respiratory failure.

Assessment of Lipid and Metabolite Changes in Obese Calf Muscle Using Multi-Echo Echo-planar Correlated Spectroscopic Imaging

Obesity-related conditions including heart disease, stroke, and type 2 diabetes are leading causes of preventable death. Recent evidence suggests that altered myocellular lipid metabolism in obesity may lead to increased insulin resistance (IR) that predisposes to these disorders. To test the hypothesis that muscles rich in type I vs. type II muscle fibers would exhibit similar changes in intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) content in obesity, we utilized a new four-dimensional multi echo echo-planar correlated spectroscopic imaging technique that allows separate determination of IMCL and EMCL content in individual calf muscles in obese vs. normal healthy human subjects. Calf muscles were scanned in 32 obese and 11 healthy subjects using a 3T MRI/MRS scanner, and IR in the obese subjects was documented by glucose tolerance testing. In obese subjects, elevation of both IMCL and EMCL content was observed in the gastrocnemius and tibialis anterior muscles (with mixed type I and II fiber content), while a significant increase in only IMCL content (+48%, p < 0.001) was observed in the soleus muscle (predominantly type I fibers). These observations indicate unexpected differences in changes in myolipid metabolism in type I vs. type II rich muscle regions in obesity, perhaps related to IR, and warrant further investigation.

Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)

The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.

Características de carcaça de cabritos criados em dois sistemas de terminação

Avaliaram-se as características da carcaça de cabritos Saanen confinados, Saanen e 7/8 Boer - 1/8 Saanen semiconfinados, bem como a influência de grupo genético e sistema de terminação sobre o rendimento comercial, índice de compacidade, não constituintes, área de olho de lombo, força de cisalhamento, gordura, teor de umidade e teor de extrato etéreo. Utilizaram-se 31 machos inteiros, com aproximadamente 128 dias de idade e 22,9±2,4kg de peso vivo. Destes, 22 eram da raça Saanen e nove animais eram mestiços 7/8 Boer - 1/8 Saanen. Os animais da raça Saanen foram divididos em dois grupos de 11 animais, sendo um grupo mantido em confinamento e outro em semiconfinamento, enquanto os mestiços foram mantidos em semiconfinamento. Compararam-se os sistemas de terminação na raça Saanen, e os grupos genéticos no sistema semiconfinado. Os animais confinados receberam 3,5% do PV em ração completa peletizada; os semiconfinados tiveram acesso à pastagem e suplementação de 1,5% do PV em ração concentrada peletizada. Aos 47 dias de terminação, os animais foram abatidos e as características de carcaça determinadas por meio de uma amostra de lombo dissecado. Foram observadas diferenças entre sistemas de terminação para rendimento comercial de carcaça, índice de compacidade da carcaça, não constituintes de carcaça, área de olho de lombo, força de cisalhamento, gordura, teor de umidade e de extrato etéreo. Entre os grupos genéticos, foram observadas diferenças para área de olho de lombo, espessura de gordura e matéria mineral. O sistema de terminação exerceu influência sobre as características de carcaça avaliadas. A raça Saanen pode ser utilizada para a produção de carne quando submetida ao confinamento.

The role of bile acids in the neoplastic progression of Barrett's esophagus - a short representative overview

Barrett's esophagus (BE) is an intestinal metaplasia of the distal esophagus in which squamous cells are replaced by a columnar epithelium. It is considered as a premalignant lesion, which can lead to esophageal adenocarcinoma, a very aggressive type of cancer, and can often be found in patients with gastro-esophageal reflux disease (GERD). In spite of the widespread use of acid-suppressing therapy with proton pump inhibitors, the incidence of adenocarcinoma has been steadily rising during the last 30 years. So, it can strongly be suggested that refluxed material other than acid might contribute to the progression of cancer within Barrett's esophagus. Along with gastric acid, bile acids enter the esophagus during an episode of reflux, and bile acids may be important in carcinogenesis. In their refluxates, patients with GERD and BE show high concentrations of the hydrophobic bile salt deoxycholic acid (DCA), which has cytotoxic effects and is able to induce DNA damage in different cell types. Other bile acids, like the hydrophilic urodeoxycholic acid (UDCA), have been therapeutically used to treat cholestatic liver diseases and to prevent colon carcinoma. This article reviews the effects of bile acids and points out new perceptions in the progression of Barrett's-associated carcinogenesis.

Effect of inactive dry yeast from sugar cane as protein source on rumen fermentation in Saanen goats

Five castrated and ruminally cannulated Saanen goats (±48.19kg) were used to evaluate intake, digestibility and rumen fermentation parameters of diets with inactive dry yeast as a soybean meal substitute (0, 25, 50, 75 and 100%). Goats were randomly assigned to a 5×5 (five levels of dry yeast x five periods) Latin square design. Diets were composed of corn silage (40%), ground corn, soybean meal and/or dry yeast and mineral supplement. The intake and digestibility of DM, OM, CP, NDF and TC were not influenced by the treatments. However, EE intake showed negative linear effect. The TDN content did not change with the inclusion of dry yeast in the diets. The pH, N-NH3 concentration and rumen short-chain fatty acids content did not differ among diets. Rumen content scanning electron microscopy observations did not suggest microbial colonization and degradation changes. Dry yeast from sugar cane can replace soybean meal in diets for Saanen goats without changing the rumen fermentation pattern, intake and digestibility.

Rapid ecological assessment of benthic indicators of water quality: a successful capacity-building experience for Brazilian postgraduate students in ecology

Rapid Ecological Assessment protocols are important tools for the training of postgraduate students, as well as the collection of data on poorly-known and protected areas with the potential for the preservation of water supplies for urban areas. The objective of this study was to perform a survey of water quality and diversity of benthic macroinvertebrates in two sub-basins at the Mata do Junco Wildlife Refuge in the Brazilian state of Sergipe. The collection of data in the field, laboratory processing, and the interpretation and discussion of data were conducted in groups by students from two postgraduate programmes in Ecology and Conservation (UFMG and UFS), personnel of the state environment agency (SEMARH), school teachers from the local town of Capela, and members of the reserve's voluntary fire brigade. The results of the assessment were organised, analysed, and presented at the reserve headquarters in the form of posters, for the development of environmental education activities with pupils from local schools, as well as contributing to a SEMARH seminar. Samples were characterised by distinct taxonomic compositions and diversity, as confirmed by MDS and additive partitioning of diversity analyses. The gravel substrate presented the lower mean taxonomic richness in each sampling unit (a1 = 28%), while the average difference among samples (b1 diversity) was elevated for both substrates (39% for leaf litter, 41% for gravel), reflecting the pronounced variation among samples, even adjacent ones within the same stream. Diversity between streams was lower in the case of leaf litter in comparison with gravel (b2 = 21 and 31%, respectively). A total of 57 fish specimens were collected with a predominance of individuals of the orders Characiformes (62%) and Perciformes (21%). This rapid ecological assessment confirmed the importance of the conservation unit and emphasised the need for its continuation, given its importance for the maintenance of water quality and its other ecological services, such as the conservation of the region's aquatic biodiversity and providing the local town of Capela (circa 20,000 inhabitants) with its water supply, the Mata do Junco being its only source.

Pulmonary hypertension diagnosed by right heart catheterisation in sickle cell disease

Recent studies have recognised the importance of pulmonary hypertension (PH) in sickle cell disease (SCD). The aim of this study was to determine the prevalence and prognostic impact of PH and its features in patients with SCD. 80 patients with SCD underwent baseline clinical evaluation, laboratory testing, 6-min walk tests (6MWTs) and echocardiography. Patients with a peak tricuspid regurgitant jet velocity (TRV) of ≥ 2.5 m·s(-1) were further evaluated through right heart catheterisation (RHC) to assure the diagnosis of PH. Our study evidenced a 40% prevalence of patients with elevated TRV at echocardiography. RHC (performed in 25 out of 32 patients) confirmed PH in 10% (95% CI 3.4-16.5%) of all patients, with a prevalence of post-capillary PH of 6.25% (95% CI 0.95-11.55%) and pre-capillary PH of 3.75% (95% CI -0.4-7.9%). Patients with PH were older, had worse performance in 6MWTs, and more pronounced anaemia, haemolysis and renal dysfunction. Survival was shorter in patients with PH. Our study reinforced the use of echocardiography as a screening tool for PH in SCD and the mandatory role of RHC for proper diagnosis. Our findings confirmed the prognostic significance of PH in SCD as its association to pronounced haemolytic profile.

Systematic review: the role of bile acids in the pathogenesis of gastro-oesophageal reflux disease and related neoplasia

BACKGROUND

Factors other than acid may play a role in gastro-oesophageal reflux disease (GERD) and its complications.

AIM

To assessed the role of bile acids in the pathogenesis of GERD, Barrett's oesophagus and Barrett's-related neoplasia.

METHODS

We conducted a systematic review of computerised bibliographic databases for original articles involving humans or human oesophageal tissue or cells that assessed exposure to or manipulation of bile acids. Outcomes assessed included GERD symptoms; gross oesophageal injury; Barrett's oesophagus and related neoplasia; and intermediate markers of inflammation, proliferation or neoplasia.

RESULTS

Eighty-three original articles were included. In in vivo studies, bile acids concentrations were higher in the oesophageal aspirates of patients with GERD than controls, and bile acids infusions triggered GERD symptoms, especially in high concentrations or in combination with acid. In ex vivo/in vitro studies, bile acids stimulated squamous oesophageal cells and Barrett's epithelial cells to produce inflammatory mediators (e.g., IL-8 and COX-2) and caused oxidative stress, DNA damage and apoptosis. They also induced squamous cells to change their gene expression pattern to resemble intestinal-type cells and caused Barrett's cells to increase expression of intestinal-type genes.

CONCLUSIONS

In aggregate, these studies suggest that bile acids may contribute to the pathogenesis of symptoms, oesophagitis and Barrett's metaplasia with related carcinogenesis in patients with GERD. However, all study results are not uniform and substantial differences in study parameters may explain at least some of this variation.

Survival in incident and prevalent cohorts of patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease. We studied 674 consecutive adult patients who were prospectively enrolled in the French PAH registry (121 incident and 553 prevalent cases). Two survival analyses were performed. First, the cohort of 674 patients was followed for 3 yrs after study entry and survival rates described. Then, we focused on the subset with incident idiopathic, familial and anorexigen-associated PAH (n = 56) combined with prevalent patients who were diagnosed <3 yrs prior to study entry (n = 134). In the cohort of 674 patients, 1-, 2-, and 3-yr survival rates were 87% (95% CI 84-90), 76% (95% CI 73-80), and 67% (95% CI 63-71), respectively. In prevalent idiopathic, familial and anorexigen-associated PAH, 1-, 2-, and 3-yr survival rates were higher than in incident patients (p = 0.037). In the combined cohort of patients with idiopathic, familial and anorexigen-associated PAH, multivariable analysis showed that survival could be estimated by means of a novel risk-prediction equation using patient sex, 6-min walk distance, and cardiac output at diagnosis. This study highlights survivor bias in prevalent cohorts of PAH patients. Survival of idiopathic, familial and anorexigen-associated PAH can be characterised by means of a novel risk-prediction equation using patients' characteristics at diagnosis.

Characteristics of joint involvement and relationships with systemic inflammation in systemic sclerosis: results from the EULAR Scleroderma Trial and Research Group (EUSTAR) database

OBJECTIVE

To determine the prevalence of and independent factors associated with joint involvement in a large population of patients with systemic sclerosis (SSc).

METHODS

This study was cross-sectional, based on data collected on patients included in the European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) registry. We queried this database to extract data regarding global evaluation of patients with SSc and the presence of any clinical articular involvement: synovitis (tender and swollen joints), tendon friction rubs (rubbing sensation detected as the tendon was moved), and joint contracture (stiffness of the joints that decreased their range of motion). Overall joint involvement was defined by the occurrence of synovitis and/or joint contracture and/or tendon friction rubs.

RESULTS

We recruited 7286 patients with SSc; their mean age was 56 +/- 14 years, disease duration 10 +/- 9 years, and 4210 (58%) had a limited cutaneous disease subset. Frequencies of synovitis, tendon friction rubs, and joint contractures were 16%, 11%, and 31%, respectively. Synovitis, tendon friction rubs, and joint contracture were more prevalent in patients with the diffuse cutaneous subset and were associated together and with severe vascular, muscular, renal, and interstitial lung involvement. Moreover, synovitis had the highest strength of association with elevated acute-phase reactants taken as the dependent variable.

CONCLUSION

Our results highlight the striking level of articular involvement in SSc, as evaluated by systematic examination in a large cohort of patients with SSc. Our data also show that synovitis, joint contracture, and tendon friction rubs are associated with a more severe disease and with systemic inflammation.