96 resultados para Gastrointestinal-tract
Resumo:
Consumption of arsenic (As) wine is a traditional activity during the classic Chinese festival of Duanwu, colloquially known worldwide as the Dragon Boat Day. Arsenic wine is drunk on the morning of the fifth day of the fifth lunar calendar month to commemorate the death of Qu Yuan, a famed Chinese poet who drowned himself in protest of a corrupt government, and to protect against ill fortune. Although realgar minerals are characteristically composed of sparingly soluble tetra-arsenic tetra-sulfides (As(4)S(4)), purity does vary with up to 10% of As being present as non-sulfur bound species, such as arsenate (As(v)) and arsenite (As(III)). Despite, the renewed interest in As speciation and the bioaccessibility of the active As components in realgar based Chinese medicines, little is known about the safety surrounding the cultural practice of drinking As wine. In a series of experiments the speciation and solubility of As in a range of wines were investigated. Furthermore, a simulated gastrointestinal system was employed to predict the impact of digestive processes on As bioavailability. The predominant soluble As species found in all the wines were As(III) and As(v). Based on typical As wine recipes employing 0.1 g realgar mL(-1) wine, the concentration of dissolved As ranged from ca. 100 to 400 mg L(-1) depending on the ethanol content of the preparation: with the As solubility found to be higher in wines with a lower proportion of ethanol. Based on a common 100 mL measure of wine with a concentration of 400 mg As L(-1), the amount of soluble As would equate to around half of the acute minimal lethal dose for adults. This is likely an underestimate of the bioaccessible concentration, as a three-fold increase in bioaccessibility could be observed in the intestinal phase based on the results from the stimulated gastrointestinal system. (C) 2011 Elsevier B.V. All rights reserved.
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Respiratory syncytial virus (RSV) is a major pathogen that primarily infects airway epithelium. Most infants suffer mild upper respiratory tract (URT) symptoms, while approximately one third progress to lower respiratory tract (LRT) involvement. Despite the ubiquity of URT infection, little is known about the relative cytopathogenesis of RSV infection in infant URT and LRT.
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Background: Chronic antigenic stimulation may initiate non-Hodgkin (NHL) and Hodgkin lymphoma (HL) development. Antecedent, infection-related conditions have been associated, but evidence by lymphoproliferative subtype is limited. Methods: From the US SEER-Medicare database, 44 191 NHL, 1832 HL and 200 000 population-based controls, frequency-matched to all SEER cancer cases, were selected. Logistic regression models, adjusted for potential confounders, compared infection-related conditions in controls with HL and NHL patients and by the NHL subtypes diffuse large B-cell, T-cell, follicular and marginal zone lymphoma (MZL). Stratification by race was undertaken. Results: Respiratory tract infections were broadly associated with NHL, particularly MZL. Skin infections were associated with a 15–28% increased risk of NHL and with most NHL subtypes, particularly cellulitis with T-cell lymphoma (OR 1.36, 95%CI 1.24–1.49). Only herpes zoster remained associated with HL following Bonferroni correction (OR 1.55, 95% CI 1.28–1.87). Gastrointestinal and urinary tract infections were not strongly associated with NHL or HL. In stratified analyses by race, sinusitis, pharyngitis, bronchitis and cellulitis showed stronger associations with total NHL in blacks than whites (P<0.001). Conclusions: Infections may contribute to the aetiologic pathway and/or be markers of underlying immune modulation. Precise elucidation of these mechanisms may provide important clues for understanding how immune disturbance contributes to lymphoma.
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Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) to patients with cystic fibrosis (CF) frequently results in chronic respiratory tract carriage. This is an increasing problem, adds to the burden of glycopeptide antibiotic use in hospitals, and represents a relative contraindication to lung transplantation. The aim of this study was to determine whether it is possible to eradicate MRSA with prolonged oral combination antibiotics, and whether this treatment is associated with improved clinical status. Adult CF patients (six male, one female) with chronic MRSA infection were treated for six months with rifampicin and sodium fusidate. Outcome data were examined for six months before treatment, on treatment and after treatment. The patients had a mean age of 29.3 (standard deviation=6.3) years and FEV(1) of 36.1% (standard deviation=12.7) predicted. The mean duration of MRSA isolation was 31 months. MRSA isolates identified in these patients was of the same lineage as the known endemic strain at the hospital when assessed by pulsed-field gel electrophoresis. Five of the seven had no evidence of MRSA during and for at least six months after rifampicin and sodium fusidate. The proportion of sputum samples positive for MRSA was lower during the six months of treatment (0.13) and after treatment (0.19) compared with before treatment (0.85) (P<0.0001). There was a reduction in the number of days of intravenous antibiotics per six months with 20.3+/-17.6 on treatment compared with 50.7 before treatment and 33.0 after treatment (P=0.02). There was no change in lung function. Gastrointestinal side effects occurred in three, but led to therapy cessation in only one patient. Despite the use of antibiotics with anti-staphylococcal activity for treatment of respiratory exacerbation, MRSA infection persists. MRSA can be eradicated from the sputum of patients with CF and chronic MRSA carriage by using rifampicin and sodium fusidate for six months. This finding was associated with a significant reduction in the duration of intravenous antibiotic treatment during therapy.
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Objectives. To conduct a prospective evaluation to determine the utility of the BTA stat test in the detection of upper tract transitional cell carcinoma (UTTCC). Monitoring for UTTCC currently relies on invasive procedures such as upper tract imaging, ureteral washing cytology (UWC) and/or ureteroscopy, or voided urine cytology (VUC). The BTA stat test is a sensitive qualitative immunoassay that detects human complement factor H-related protein in voided urine.
Methods. A total of 81 patients participated, 27 with histopathologically confirmed UTTCC, 26 with upper tract calculi, and 28 with microscopic hematuria but no evidence of urologic disease. Voided specimens collected before surgery or treatment were tested with the BTA stat test and VUC. UWC was performed in specimens collected by a ureteral catheter.
Results. The BTA stat test was significantly more sensitive and specific than VUC or UWC. The overall sensitivity for each was 82%, 11%, and 48%; the specificity was 89%, 54%, and 33%. The positive predictive value for the BTA stat test was 79% and the negative predictive value was 91%, both the highest of the three tests.
Conclusions. The BTA stat test was superior to VUC and UWC in the detection of UTTCC. These results may support the adoption of a less aggressive follow-up policy when monitoring for UTTCC when the BTA stat result is negative. If cystoscopy is negative and the BTA stat test is positive, upper tract investigations should be expedited and, if the bladder is in place, bladder biopsies performed. (C) 2001, Elsevier Science Inc.
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Introduction and aims: The role bacteria play in the development and progression of Chronic Obstructive Pulmonary Disease (COPD) is unclear. We used culture-independent methods to describe differences and/or similarities in microbial communities in the lower airways of patients with COPD, healthy non-smokers and smokers.
Methods: Bronchial wash samples were collected from patients with COPD (GOLD 1–3; n = 18), healthy non-smokers (HV; n = 11) and healthy smokers (HS; n = 8). Samples were processed using the Illumina MiSeq platform. The Shannon-Wiener Index (SW) of diversity, lung obstruction (FEV1/FVC ratio) and ordination by Non-Metric Multidimensional Scaling (NMDS) on Bray-Curtis dissimilarity indices were analysed to evaluate how samples were related. Principal component analysis (PCA) was performed to assess the effect specific taxa had within each cohort. Characteristics of each cohort are shown in Table 1.
Results: There was no difference in taxa richness between cohorts (range: 69–71; p = 0.954). Diversity (SW Index) was significantly lower in COPD samples compared to samples from HV and HS (p = 0.009 and p = 0.033, respectively). There was no significant difference between HV and HS (p = 0.186). The FEV1/FVC ratio was significantly lower for COPD compared to HV (p = 9*10–8) and HS (p = 2*10–6), respectively. NMDS analysis showed that communities belonging to either of the healthy groups were more similar to each other than they were to samples belonging to the COPD group. PCA analysis showed that members of Streptococcus sp. and Haemophilus sp. had the largest effect on the variance explained in COPD. In HS, Haemophilus sp., Fusobaterium sp., Actinomyces sp., Prevotella sp. and Veillonella sp. had the largest effect on the variance explained, while in HV Neisseria sp., Porphyromonas sp., Actinomyces sp., Atopobium sp., Prevotella and Veillonella sp. had the largest effect on the variance explained.
Conclusions: The study demonstrates that microbial communities in the lower airways of patients with COPD are significantly different from that seen in healthy comparison groups. Patients with COPD had lower microbial diversity than either of the healthy comparison groups, higher relative abundance of members of Streptococcus sp. and lower relative abundance of a number of key anaerobes.Characteristics
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Introduction and Aims: The identification of complex chronic polymicrobial infections, such as those observed in the cystic fibrosis (CF) airways, are often a diagnostic challenge. Few studies have compared culture-dependent methods with molecular identification making it hard to describe bacterial communities in a comprehensive manner. The aim of the study is to compare four different methods with respect to their similarities and differences in detection of bacteria. Methods: We compared41 sputum samples fromroutine clinical-culture, extended-culture (aerobic and anaerobic), and molecular identification such as Roche 454-FLX Titanium and T-RFLP to assess concurrence between methodologies in detecting bacteria. The agreement between methodologies in detecting either absence or presence of bacterial taxa was assessed by Kappa (κ) statistics. Results: The majority of bacterial taxa identified by culture were also identified with molecular analysis. In total 2, 60, 25, and 179 different bacterial taxa were identified with clinical-culture, extended-culture, T-RFLP and 454-FLX respectively. Clinical-culture, extended-culture and T-RFLP were poor predictors of species richness when compared to 454-FLX (p < 0.0001). Agreement between methods for detecting Pseudomonas sp. and Burkholderia sp. was good with κ ≥ 0.7 [p < 0.0001] and κ ≥ 0.9 [p < 0.0001] respectively. Detection of anaerobic bacteria, such as Prevotella sp. and Veillonella sp., was moderate between extended-culture and 454-FLX with κ = 0.461 [p < 0.0001] and κ = 0.311 [p = 0.032] respectively, and good between T-RFLP and 454-FLX with κ = 0.577 [p < 0.0001] and κ = 0.808 [p < 0.0001] respectively. Agreement between methods for other main bacterial taxa, such as Staphylcoccus sp. and Streptococcus sp., was poor with only a moderate agreement for detection of Streptococcus sp. observed between T-RFLP and 454-FLX (κ = 0.221 [p = 0.024]). Conclusions: This study demonstrates the increased sensitivity culture-independent microbial identification such as the 454-FLX have over clinical-culture, extended-culture and T-RFLP methodologies. The extended-culture detected majority of the most prevalent bacterial taxa associated with chronic colonisation of the CF airways which were also detected by culture-independent methodologies. However, agreement between methods in detecting number of potentially relevant bacteria is largely lacking.
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Gastrointestinal hormones such as cholecystokinin (CCK), glucagon like peptide 1 (GLP-1), and peptide YY (PYY) play an important role in suppressing hunger and controlling food intake. These satiety hormones are secreted from enteroendocrine cells present throughout the intestinal tract. The intestinal secretin tumor cell line (STC-1) possesses many features of native intestinal enteroendocrine cells. As such, STC-1 cells are routinely used in screening platforms to identify foods or compounds that modulate secretion of gastrointestinal hormones in vitro. This chapter describes this intestinal cell model focussing on it’s applications, advantages and limitations. A general protocol is provided for challenging STC-1 cells with test compounds.
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The reported incidence of gastrointestinal endocrine tumours is variable. In Northern Ireland circumstances allowing such an assessment are favourable with a central diagnostic laboratory and register established to collect data on tumours from a well-defined population of 1.5 million people. From 1970 to 1985, 368 cases were recorded of which 85 per cent were carcinoid tumours. The annual incidence of carcinoid tumours was 1.3 per 100,000 of the population and the majority occurred in the appendix (61 per cent). No patients presented with the carcinoid syndrome. The annual incidence for other tumours was 0.12 per 100,000 for insulinomas; islet cell tumours of unknown type 0.07; Zollinger-Ellison syndrome 0.05; and multiple endocrine neoplasia (MEN) 0.05. There were two cases of VIPoma, one glucagonoma, one neurotensinoma and one tumour producing ACTH. It is possible that some tumours are more uncommon than others because of difficulty in diagnosis.
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Despite the increasing availability of digital slide viewing, and numerous advantages associated with its application, a lack of quality validation studies is amongst the reasons for poor uptake in routine practice. This study evaluated primary digital pathology reporting in the setting of routine subspecialist gastrointestinal pathology, commonplace in most tissue pathology laboratories and representing one of the highest volume specialties in most laboratories. Individual digital and glass slide diagnoses were compared amongst three pathologists reporting in a gastrointestinal subspecialty team, in a prospective series of 100 consecutive diagnostic cases from routine practice in a large teaching hospital laboratory. The study included a washout period of at least 6 months. Discordant diagnoses were classified, and the study evaluated against recent College of American Pathologists (CAP) recommendations for evaluating digital pathology systems for diagnostic use. The study design met all 12 of the CAP recommendations. The 100 study cases generated 300 pairs of diagnoses, comprising 100 glass slide diagnoses and 100 digital diagnoses from each of the three study pathologists. 286 of 300 pairs of diagnoses were concordant, representing intraobserver concordance of 95.3 %, broadly comparable to rates previously published in this field. In ten of the 14 discordant pairs, the glass slide diagnosis was favoured; in four cases, the digital diagnosis was favoured, but importantly, the 14 discordant intraobserver diagnoses were considered to be of minor clinical significance. Interobserver, or viewing modality independent, concordance was found in 94 of the total of 100 study cases, providing a comparable baseline discordance rate expected in any second viewing of pathology material. These overall results support the safe use of digital pathology in primary diagnostic reporting in this setting
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Preclinical toxicity testing in animal models is a cornerstone of the drug development process, yet it is often unable to predict adverse effects and tolerability issues in human subjects. Species-specific responses to investigational drugs have led researchers to utilize human tissues and cells to better estimate human toxicity. Unfortunately, human cell-derived models are imperfect because toxicity is assessed in isolation, removed from the normal physiologic microenvironment. Microphysiological modeling often referred to as 'organ-on-a-chip' or 'human-on-a-chip' places human tissue into a microfluidic system that mimics the complexity of human in vivo physiology, thereby allowing for toxicity testing on several cell types, tissues, and organs within a more biologically relevant environment. Here we describe important concepts when developing a repro-on-a-chip model. The development of female and male reproductive microfluidic systems is critical to sex-based in vitro toxicity and drug testing. This review addresses the biological and physiological aspects of the male and female reproductive systems in vivo and what should be considered when designing a microphysiological human-on-a-chip model. Additionally, interactions between the reproductive tract and other systems are explored, focusing on the impact of factors and hormones produced by the reproductive tract and disease pathophysiology.