Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND: Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori. OBJECTIVES: To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started. SEARCH METHODS: We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively. SELECTION CRITERIA: We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as13C or14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities. MAIN RESULTS: We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons. AUTHORS' CONCLUSIONS: In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions

Melatonin ameliorates oxidative damage in hyperglycemia-induced liver injury

Purpose: Melatonin (N-acetyl-5-methoxy-tryptamine) is synthesized mainly by the pineal gland and its antioxidant properties have been demonstrated both in short and long term studies. Our aim was to clarify the effects of hyperglycemia and to administer melatonin on lipid peroxidation, protein oxidation and oxidative DNA damage in rat. Methods: Malondialdehyde (MDA), protein carbonyl (PCO) and total thiol (T-SH) levels were determined in plasma and liver tissue, glutathione (GSH) levels in erythrocyte and liver tissue, and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels in plasma and liver. Thirty-eight male Wistar rats were divided into four groups: 1 - injected with saline (n = 8), 2 - injected with melatonin (n = 10), 3 - injected with STZ (65 mg/kg, i.p.) (diabetic group) (n = 10) and 4 - injected with melatonin (10 mg/kg/day, i.p.) and STZ (65 mg/kg, i.p.) (n = 10) for 8 weeks (diabetic+ melatonin group). Colorimetric methods were used to determine the level of the oxidative stress markers. 8-OhdGwas measured using ELISA. Results: MDA, PCO and 8-OHdG levels in the plasma and the liver homogenates of diabetic rats were higher than controls and were significantly reduced after melatonin treatment. T-SH and GSH levels in samples were markedly reduced in untreated diabetic rats compared with control rats; however, these parameters were increased in diabetic rats following melatonin treatment. Conclusion: Our findings showed that melatonin administration partially ameliorated oxidative damage in liver injury in STZ-induced diabetic rats. The present study suggests that melatonin functions as a potent antioxidant agent in diabetes. Melatonin, a nutritional supplement, may be a good therapeutic option for diabetic patients

Investigation of the Presence of Blastocystis spp. in Stool Samples with Microscopic, Culture and Molecular Methods

Blastocystis species are enteric protozoa frequently detected in human and animals. Seventeen subtypes (STs) have now been identified, nine of them isolating from humans. The pleomorphic structure and genetic diversity of Blastocystis spp. and the absence of standardized diagnostic methods complicate the evaluation of current data. Microscopic methods such as native-lugol and trichrome staining are most frequently used methods in routine diagnosis, while culture and molecular methods are preferred for research purposes. The aims of this study were to investigate the presence of Blastocystis spp. in the stool samples of patients with gastrointestinal complaints by microscopic and culture methods, and to detect the subtypes of isolates by polymerase chain reaction (PCR). A total of 350 stool samples collected from patients with diarrhea (n= 157) and without diarrhea (n= 193) were included in the study. Presence of Blastocystis spp. in the samples were investigated by native-lugol examination, trichrome staining and direct fluorescent antibody (DFA) methods. Ringer's solution containing 10\% horse serum and 0.05\% asparagine was used for cultivation. The cultures were evaluated after 3-4 days of incubation at 37 degrees C by microscopic examination. The subtypes of Blastocystis spp. strains isolated from the cultures have been identified by PCR using sequence-tagged site primers. A total of 66 (19\%) stool samples, of them 26 (16.6\%) were from diarrheal and 40 (21\%) from non-diarrheal cases, yielded Blastocystis sp. growth in culture. Among the evaluated samples, 12\% (42/350) were found positive with native-lugol examination, 17\% (58/350) with trichrome staining, and 19\% (66/350) with DFA method. The agreement of culture and native-lugol method was estimated as strong (kappa= 0.752), while it was very strong between culture with trichrome staining and DFA methods (kappa= 0.922 and kappa= 1.00, respectively). When the culture was accepted as reference method, the sensitivity and specificity rates of native-lugol method were 65\% and 100\%, trichrome staining method were 88\% and 100\%, and DFA method were 100\% and 100\%, respectively. Forty-three (65\%) of Blastocystis spp. positive samples were subtyped by PCR, while 23 isolates could not be subtyped. The most frequent detected subtype was ST3 (12/43; 28\%), followed by ST1 (6/43; 13.9\%), ST4 (5/43; 11.6\%) and ST7 (5/43; 11.6\%), ST2 (3/43; 7\%) and ST6 (1/43; 2.3\%). ST5 was not detected in this study and 11(25.6\%) samples have been identified to have mixed subtypes. The differences of Blastocystis spp. positivity rates and the distribution of the subtypes between the patients with or without diarrhea were not found statistically significant (p> 0.05). In our study, ST3 was the most frequently identified Blastocystis spp. subtype, similar to the previous national studies, however ST6 and ST7 have been identified for the first time. In conclusion, as the sensitivity of native-lugol examination is low, culture is time-consuming and laborious and PCR methods are costly and non-standardized, rapid, practical and high sensitive DFA is considered as the favourable method in the diagnosis of Blastocystis spp. in routine laboratories

Assessment of Effects of Thyrotoxicosis on Gallstone Formation in Rabbits

WOS: 000461743400017Aim: The etiopathogenesis of gallstone formation is well known, but only a few studies have investigated the effects of thyrotoxicosis on gallstone formation. In this study, we investigated the contribution of thyrotoxicosis to gallstone formation in rabbits. Methods: Forty-four New Zealand rabbits were used. The rabbits were divided into six groups, with each group receiving a different diet. At the end of seven weeks, all rabbits were sacrificed, blood was collected for analysis, and cholecystectomy was performed. Results: Serum levels of both free triiodothyronine (FT3) and thyroxine (FT4) were significantly higher in rabbits receiving thyroid hormone (p0.05). Conclusions: Thyrotoxicosis promotes an increase in gallstone formation risk as a result of an increased bile CSI and gallbladder mucosal inflammation

Desflurane anaesthesia in a patient with multiple sclerosis in total hip replacement

A b s t r a c t Multiple sclerosis (MS) is a progressive demyelinating disease presenting with a relapsing-remitting course and affects large areas of the brain and the spinal cord. Surgical stress often induces exacerbation of MS symptoms. It is mandatory to prepare the MS patient very carefully for the surgery and anaesthesia with an effective premedication and an effective postoperative analgesia following a safe and minimal-risk anaesthesia management. In recent reports, results of general and regional anaesthesia in MS patients have been discussed. To our knowledge this is the first case report of the use of desflurane anaesthesia in a patient with MS. In conclusion, desflurane anaesthesia is a safe and useful method for MS patients

Oxidative damage parameters in renal tissues of aged and young rats based on gender

Purpose: Aging is characterized by a gradual functional decrease of all systems including the kidneys. Growing evidence links altered lipid protein redox-homeostasis with renal dysfunction. The effect of sexual dimorphism on the lipid protein redox-homeostasis mechanisms in the aging kidney is obscure. In the current study, we aimed to investigate redox homeostasis as it related to sexual dimorphism on protein oxidation and lipid peroxidation parameters, as protein carbonyl (PCO), total thiol (T-SH), advanced oxidation protein products (AOPP), malondialdehyde, glutathione (GSH), and superoxide dismutase (SOD) activity, as potential aging biomarkers, which may contribute to an analysis of the free radical theory of aging