Prioritization of Genetic Variants Predisposing to Alzheimer's Disease in Young Healthy Bulgarian Individuals Using Centenarian Exomes

The present study aims to identify pathogenic/risky variants in the exomes of healthy young individuals predisposing to Alzheimer's disease (AD) by their validation in centenarian's exomes. The group of Bulgarian centenarians included 32 individuals (mean age 102.4) without AD diagnosis and the matched control group of 61 young healthy individuals (mean age 21.9). Two DNA pools were constructed with equimolar amounts of DNA from each participant and whole exome sequencing analysis (WES) was performed. We examined the WES data for pathogenic or risky SNPs predisposing to AD. Of altogether 1929 variants selected from DisGeNet database for association with AD, only 174 (9.02%) were detected in our WES data. One hundred and fifty-two (152) SNPs were present in both studied groups, 8 in centenarians and 14 in controls only. Seven variants have significantly higher frequency in young individuals or absence in centenarians. Based on sufficiently unambiguous literature data, we nominated rs63750264 in APP, rs429358 in APOE, rs1800562 in HFE variants for predisposition to AD in young individuals. To a lesser extent, the carriership of rs2070045 in SORL1, rs6265 in BDNF, rs769449 in APOE, rs4988514 in SST can increase the risk to AD development. These variants could find implication in the Alzheimer's disease estimation in young individuals before the onset of clinical symptoms.

Thrombotic incidents in patients with myelofibrosis suggest to be independent of JAK2 V617f mutational status

INTRODUCTION

Myelofibrosis (MF) belongs to a group of conditions known as Philadelphia-negative myeloproliferative neoplasms (MPN). Bleeding or various vascular complications could be the main causes of morbidity and mortality in patients with MF. MPNrelated thrombosis is a multifactorial process and in the case of myelofibrosis, little is known. The risk factors for thrombotic complications in MF have been rarely assessed.

AIM

The purpose of this study was to investigate the incidence of thrombotic events in MF and the role of JAK2 V617F mutation as a risk factor for thrombotic incidents in patients with MF.

MATERIALS AND METHODS

In our study of 37 patients, 35% had thrombotic events in the past. All patients were admitted to the Clinic of Hematology, St Ivan Rilski University Hospital, Sofia, Bulgaria between 2016 and 2019 and diagnosed based on the WHO criteria of 2016.

RESULTS

The majority of patients (23, 62%) proved positive for JAK2 (Janus kinase) V617F mutation carrying one (16, 70%) or two (7, 30%) mutated alleles. Thirteen of the patients (35%) had a thrombotic event in the past and 9 of them (69%) were carriers of JAK2 V617F mutation. Fourteen patients of those without thrombotic history (24, 58%) were also carriers of JAK2 V617F mutation.

CONCLUSIONS

As a whole, we did not find a statistically significant difference between JAK2 V617F mutation and the frequency of thrombotic events. Rendering an account to the possible life-threatening complications, treatment decisions should be undertaken upon possible antithrombotic prevention in MF.

Centenarian Exomes as a Tool for Evaluating the Clinical Relevance of Germline Tumor Suppressor Mutations

Objectives:

The aim of the present study was to evaluate the clinical relevance of mutations in tumor suppressor genes using whole-exome sequencing data from centenarians and young healthy individuals.

Methods:

Two pools, one of centenarians and one of young individuals, were constructed and whole-exome sequencing was performed. We examined the whole-exome sequencing data of Bulgarian individuals for carriership of tumor suppressor gene variants.

Results:

Of all variants annotated in both pools, 5080 (0.06%) are variants in tumor suppressor genes but only 46 show significant difference in allele frequencies between the two studied groups. Four variants (0.004%) are pathogenic/risk factors according to single nucleotide polymorphism database: rs1566734 in PTPRJ, rs861539 in XRCC3, rs203462 in AKAP10, and rs486907 in RNASEL.

Discussion:

Based on their high minor allele frequencies and presence in the centenarian group, we could reclassify them from pathogenic/risk factors to benign. Our study shows that centenarian exomes can be used for re-evaluating the clinically uncertain variants.

Unbalanced human embryos secrete more hyperglycosylated human chorionic gonadotrophin (hCG-H) than balanced ones

PURPOSE

The aim of this study was to compare the levels of hyperglycosylated human chorionic gonadotropin (hCG-H) secreted from balanced and unbalanced human embryos.

METHODS

Single-step culture media samples from 155 good quality embryos, derived from 90 good prognosis patients undergoing intracytoplasmic sperm injection (ICSI), were collected on the fifth day of embryo cultivation. All embryos were tested by next-generation sequencing (NGS) technique. The hCG-H levels in the culture media were evaluated by ELISA kit (Cusabio Biotech, CBS-E15803h) according to the manufacturer's instructions. Statistical analysis was performed using SPSS v.21 (IBM Corp., Armonk, NY, USA).

RESULTS

The NGS analysis revealed that 36% of the embryos (n = 56) were balanced, and 64% of the embryos were unbalanced (n = 99). The presence of hCG-H was confirmed in all embryo culture media samples but was absent in the negative control. In addition, hCG-H concentration was significantly higher in the culture media from unbalanced embryos compared with the balanced ones (0.72 ± 0.30 mIU/ml vs. 0.62 ± 0.12 mIU/ml, p = 0.02, respectively). Furthermore, the mean levels of hCG-H were significantly increased in the samples from embryos with multiple abnormalities. Finally, the highest levels of hCG-H were expressed from embryos with monosomy of chromosome 11 (1.28 ± 0.04 mIU/ml) and those with trisomies of chromosomes 21 (2.23 mIU/ml) and 4 (1.02 ± 0.35 mIU/ml).

CONCLUSION

Our results suggest that chromosomal aberrations in human embryos are associated with an increased secretion of hCG-H. However, hCG-H concentration in embryo culture media as a single biomarker is not sufficient for an accurate selection of balanced embryos.

Philadelphia-positive case negative for JAK2 V617F mutation with hyperdiploidic karyotype: A case report

Chronic myeloid leukemia (CML) is one of the most common hematological malignancies and accounts for 15-20% of all leukemia cases. The cytogenetic marker of CML is the presence of Philadelphia chromosome (Ph) in >95% of patients. The current case reports a 83-year old woman who was directed to the genetic laboratory for a cytogenetic and molecular-genetic analysis suspected to be Ph positive [(+)]. Karyotype analysis of a bone marrow sample revealed a hyperdiploid karyotype in a part of Ph (+) cells with additional chromosomes 8, 10 and 12. Restriction analysis for V617F JAK2 mutation was negative, while the quantitative RT-qPCR assay indicated BCR-ABL/ABL transcript at the level of 120% International Scale (IS). Generally cytogenetic complexities are important in the prognostic evaluation of CML. Besides the Ph chromosome, a variet of chromosomal aberrations may be associated with CML. A total of 5-10% of these cases show complex translocations involving another chromosome. The current case is Ph(+) demonstrating an additional hyperdiploid karyotype clone with three additional autosomes (8, 10 and 12). This case highlights the significance of cytogenetic abnormalities on the prognosis of CML.

[Glucocorticosteroids for people with alcoholic hepatitis (Cochrane review)]

Alcoholic hepatitis (AH) is a form of alcoholic liver disease. Glucocorticosteroids (GCS) are used as anti - inflammatory drugs for people with alcoholic hepatitis.

AIM

To assess the benefits and harms of GCS in people with AH.

MATERIAL AND METHODS

We identified trials through electronic searches in Cochrane Hepato-Biliary's (CHB) Controlled Trials Register, CENTRAL, MEDLINE, Embase, LILACS, and Science Citation Index Expanded. We considered for inclusion randomised clinical trials (RCTs) assessing GCS versus placebo/no intervention in adult participants with AH. We allowed co - interventions in the trial groups if they were similar. We followed Cochrane methodology, CHB Group methodology using Review Manager 5 and Trial Sequential Analysis(TSA) to perform meta - analysis (M-A), assessed bias risk of the trials, certainty of evidence using GRADE.

RESULTS AND DISCUSSION

Sixteen trials fulfilled the inclusion criteria. Fifteen trials provided data for analysis (927 participants received GCS, 934 - placebo/no intervention). The GCS were administered to adult participants at different stages of AH orally or parenterally for a median of 28 days. There was no evidence of effect of GCCs on our primary outcomes all - cause mortality up to 3 months following randomisation (RR 0.90, 95% CI 0.70-1.15; n=1861), on health - related quality of life (MD - 0.04 points; 95% CI -0.11-0.03; n=377; trial = 1) (EQ-5D-3L scale), on the occurrence of serious adverse events during treatment (RR 1.05, 95% CI 0.85-1.29; n=1861). We found no evidence of a difference between the intervention groups. The risk of bias was high in all the trials except one. The certainty of evidence was very low or low. One of the trials seems to be not industry - funded.

CONCLUSION

We found no evidence of a difference between GCS and placebo or no intervention on all - cause mortality, health - related quality of life, and serious adverse events during treatment. We cannot exclude increases in adverse events and cannot rule out significant benefits and harms of GCSs. Future trials ought to report depersonalised individual participant data.

Familial Papillary Thyroid Carcinoma (FPTC): a Retrospective Analysis in a Sample of the Bulgarian Population for a 10-Year Period

In recent years, there are numerous reports indicating the presence of familial papillary carcinoma. Unfortunately, no genetic defect can be linked directly to the disease. In this study, we set the goal to make a retrospective analysis of the cases with papillary carcinoma in the Department of Endocrine Surgery for the past 10 years, to compare the characteristics of sporadic and familial forms of the disease and to find families with hereditary papillary carcinoma. The study included 810 patients treated for thyroid cancer in the Department of Endocrine Surgery, USBALE "Acad. Iv. Penchev" Hospital, between January 1, 2006 and December 31, 2015. We used chi square test to determine statistical significant difference. The data analysis and interpretation was performed on SPSS 20.0. Both groups had similar demographic distribution. We found that 587 patients have sporadic papillary carcinoma, while 147 have a relative with thyroid pathology in the first degree of kinship. In 8 patients, there was a blood relative with thyroid cancer. When we compared the two groups, we found statistically significant difference only in tumor size. There was no significant difference in aggressiveness of the thyroid cancer (multifocality and lymph node metastasis). When analyzing the results, we identified 147 patients with a family history of thyroid disease (20%). In 8 patients (5.44%), we found at least one relative with papillary thyroid carcinoma. However, our study does not demonstrate any difference in the aggressiveness of familial and sporadic papillary thyroid carcinoma.

Systematic review with meta-analysis: diagnostic accuracy of transient elastography for staging of fibrosis in people with alcoholic liver disease

BACKGROUND

The progression of hepatic fibrosis into cirrhosis is a main prognostic factor for survival in people with alcoholic liver disease. The range of cut-off values characterising the stage of hepatic fibrosis seems to be dependent on the aetiology of the liver disease.

AIMS

To determine the diagnostic accuracy of transient elastography (the index test) for diagnosis of fibrosis in alcoholic liver disease when compared with liver biopsy (the reference standard), using the METAVIR scoring system. To establish the optimal cut-off values for the hepatic fibrosis stages.

METHODS

We followed Cochrane Methodology for diagnostic test accuracy reviews. We identified 14 studies. Among the study participants with alcoholic liver disease, 834 provided numerical data for analysis (August 2014). Only half of the studies were monoaetiology studies. We used the bivariate model and estimated the summary sensitivities and summary specificities. Hence, we calculated the summary likelihood ratios (LRs) to rule in or rule out hepatic fibrosis. We investigated pre-defined sources of heterogeneity.

RESULTS

Severe fibrosis (F3 or worse): summary (95% CI) sensitivity 0.92(0.89-0.96) and specificity 0.70(0.61-0.79); LR+ 3.1(2.1-4.1), LR- 0.11(95% CI 0.06-0.16). Cirrhosis (F4): summary (95% CI) sensitivity of 0.95(0.87-0.98) and specificity 0.71(0.56-0.82); LR+ 3.3(2.1-5.0); LR- 0.07(0.03-0.19).

CONCLUSIONS

Transient elastography may be used as a diagnostic method to exclude cirrhosis or severe fibrosis when the test is negative. Cut-off values of around 12.5 kPa for cirrhosis may be used in clinical practice, but caution is needed, as the values reported in the review are not yet prospectively validated.

Epigenetic alterations in patients with type 2 diabetes mellitus

Epigenetic changes, in particular DNA methylation processes, play a role in the pathogenesis and progression of type 2 diabetes mellitus (T2DM) linking genetic and environmental factors. To clarify this role, we have analyzed in patients with different duration of T2DM: (i) expression levels of methyl-CpG-binding domain protein 2 (MBD2) as marker of DNA methylation, and ii) methylation changes in 22 genes connected to cellular stress and toxicity. We have analyzed MBD2 mRNA expression levels in16 patients and 12 controls and the methylation status of stress and toxicity genes in four DNA pools: (i) controls; (ii) newly-diagnosed T2DM patients; (iii) patients with T2DM duration of <5 years and (iv) of >5 years. The MBD2 expression levels were 10.4-times increased on average in T2DM patients compared to controls. Consistent increase in DNA methylation fraction with the increase in T2DM duration was observed in Prdx2 and SCARA3 genes, connected to oxidative stress protection and in BRCA1 and Tp53 tumor-suppressor genes. In conclusion, increased MBD2 expression in patients indicated general dysregulation of DNA methylation in T2DM. The elevated methylation of Prdx2 and SCARA3 genes suggests disturbance in oxidative stress protection in T2DM. The increased methylation of BRCA1 and Tp53 genes unraveled an epigenetic cause for T2DM related increase in cancer risk.

Gene expression in peripheral blood of patients with hypertension and patients with type 2 diabetes

AIM

To evaluate the expression of atherosclerosis-associated genes in patients with hypertension and type 2 diabetes mellitus.

MATERIAL AND METHODS

Twenty-seven patients (14 men, 13 women), mean age 43.26 ± 11.69 years, were included in the study, which was divided into three groups: group 1 - patients with newly diagnosed hypertension and normal glucose tolerance (n = 9), group 2 - normotensive individuals with newly diagnosed type 2 diabetes (n = 9), and control group - normotensive individuals with normal glucose tolerance (n = 9). Gene expression analysis was performed with Human Atherosclerosis RT2 Profiler PCR Array.

RESULTS

In patients with hypertension, we found eight genes with increased expression - FABP3, FAS, FN1, IL1R2, LPL, SERPINE1, TGFB1, and VCAM1. Decreased expression was observed for two genes - SELPLG and SERPINEB2. In patients with type 2 diabetes we found seven up-regulated genes - APOE, BAX, MMP1, NFKB1, PDGFB, SPP1, and TGFB2, whereas no specifically down-regulated genes were observed. Three genes - KLF2, PDGFRB, and PPARD were found to be expressed only in groups 1 and 2.

CONCLUSION

Hypertension is associated with increased expression of FABP3, FAS, FN1, IL1R2, LPL, SERPINE1, TGFB1, and VCAM1 and decreased expression of SELPLG and SERPINEB2. The up-regulation of FAS, FN1, SERPINE1, TGFB1, and VCAM1 might be associated with an increased cardiovascular risk. Type 2 diabetes is associated with increased expression of APOE, BAX, MMP1, NFKB1, PDGFB, SPP1, and TGFB2. KLF2 and PPARD might be part of protective mechanisms that limit target organ damage in both disease conditions. Expression of PDGFRB might play an important role in the pathogenesis of both hypertension and type 2 diabetes.

Meta-analysis: antioxidant supplements for liver diseases - the Cochrane Hepato-Biliary Group

BACKGROUND

Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal.

AIM

To assess the benefits and harms of antioxidant supplements for patients with liver diseases.

METHODS

We identified trials through electronic and manual searches until August 2009. We included randomized trials comparing antioxidant supplements (beta-carotene, vitamin A, C, E and selenium) vs. placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease and cirrhosis (any aetiology). Random-effects and fixed-effect meta-analyses were conducted. Results were presented as relative risks (RR), or mean difference (MD), both with 95% confidence intervals (CI).

RESULTS

Twenty randomized trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials) and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality [relative risk (RR) 0.84, 95% confidence interval (CI) 0.60-1.19, I(2) = 0%] or liver-related mortality (RR 0.89, 95% CI 0.39-2.05, I(2) = 37%). Stratification according to the type of liver disease assessed did not affect the conclusions. Antioxidant supplements significantly increased the activity of gamma glutamyl transpeptidase (MD 24.21 IU/L, 95% CI 6.67-41.75, I(2) = 0%).

CONCLUSIONS

We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzymes.

Assessment of risk of bias in randomized clinical trials in surgery

BACKGROUND

Meta-analysis of randomized clinical trials (RCTs) with low risk of bias is considered the highest level of evidence available for evaluating an intervention. Bias in RCTs may overestimate or underestimate the true effectiveness of an intervention.

METHODS

The causes of bias in surgical trials as described by The Cochrane Collaboration, and the methods that can be used to avoid them, are reviewed.

RESULTS

Blinding is difficult in many surgical trials but careful trial design can reduce the bias risk due to lack of blinding. It is possible to conduct surgical trials with low risk of bias by using appropriate trial design.

CONCLUSION

The risk of providing a treatment based on a biased effect estimate must be balanced against the difficulty of conducting trials with very low risk of bias. Better understanding of the risk of bias may result in improved trials with a closer estimate of the true effectiveness of an intervention.

Systematic review: primary and secondary prevention of gastrointestinal cancers with antioxidant supplements

BACKGROUND

The evidence on whether antioxidant supplements prevent gastrointestinal cancers is contradictory.

AIM

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

METHODS

Using the Cochrane Collaboration methodology, we reviewed the randomized trials comparing antioxidant supplements with placebo or no intervention on the occurrence of gastrointestinal cancers. We searched electronic databases and reference lists until October, 2007. Our outcome measures were gastrointestinal cancers, overall mortality and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence intervals (CI) based on random-effects and fixed-effect models meta-analyses.

RESULTS

We identified 20 randomized trials (211,818 participants) assessing beta-carotene, vitamin A, vitamin C, vitamin E, and selenium. The trial quality was generally high. The antioxidant supplements were without a significant effect on the occurrence of gastrointestinal cancers (RR 0.94, 95% CI 0.83-1.06, I(2) = 54.0%). The heterogeneity seemed to be explained by bias risk (low-bias risk trials RR 1.04, 95% CI 0.96-1.13 compared to high-bias risk trials RR 0.59, 95% CI 0.43-0.80, test of interaction P < 0.0005) and type of antioxidant supplement (beta-carotene potentially increasing and selenium potentially decreasing cancer risk). Antioxidant supplements had no significant effect on mortality in a random-effects model meta-analysis (RR 1.02, 95% CI 0.97-1.07, I(2) = 53.5%) but significantly increased mortality in a fixed-effect model meta-analysis (RR 1.04, 95% CI 1.02-1.07).

CONCLUSIONS

We could not find evidence that the studied antioxidant supplements prevented gastrointestinal cancers. On the contrary, they seem to increase overall mortality.

Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases

BACKGROUND

Animal and physiological research as well as observational studies suggest that antioxidant supplements may improve survival.

OBJECTIVES

To assess the effect of antioxidant supplements on mortality in primary or secondary prevention randomised clinical trials.

SEARCH STRATEGY

We searched The Cochrane Library (Issue 3, 2005), MEDLINE (1966 to October 2005), EMBASE (1985 to October 2005), and the Science Citation Index Expanded (1945 to October 2005). We scanned bibliographies of relevant publications and wrote to pharmaceutical companies for additional trials.

SELECTION CRITERIA

We included all primary and secondary prevention randomised clinical trials on antioxidant supplements (beta-carotene, vitamin A, vitamin C, vitamin E, and selenium) versus placebo or no intervention. Included participants were either healthy (primary prevention trials) or had any disease (secondary prevention trials).

DATA COLLECTION AND ANALYSIS

Three authors extracted data. Trials with adequate randomisation, blinding, and follow-up were classified as having a low risk of bias. Random-effects and fixed-effect meta-analyses were performed. Random-effects meta-regression analyses were performed to assess sources of intertrial heterogeneity.

MAIN RESULTS

Sixty-seven randomised trials with 232,550 participants were included. Forty-seven trials including 180,938 participants had low risk of bias. Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases (gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified). Overall, the antioxidant supplements had no significant effect on mortality in a random-effects meta-analysis (relative risk [RR] 1.02, 95% confidence interval [CI] 0.99 to 1.06), but significantly increased mortality in a fixed-effect model (RR 1.04, 95% CI 1.02 to 1.06). In meta-regression analysis, the risk of bias and type of antioxidant supplement were the only significant predictors of intertrial heterogeneity. In the trials with a low risk of bias, the antioxidant supplements significantly increased mortality (RR 1.05, 95% CI 1.02 to 1.08). When the different antioxidants were assessed separately, analyses including trials with a low risk of bias and excluding selenium trials found significantly increased mortality by vitamin A (RR 1.16, 95% CI 1.10 to 1.24), beta-carotene (RR 1.07, 95% CI 1.02 to 1.11), and vitamin E (RR 1.04, 95% CI 1.01 to 1.07), but no significant detrimental effect of vitamin C (RR 1.06, 95% CI 0.94 to 1.20). Low-bias risk trials on selenium found no significant effect on mortality (RR 0.91, 95% CI 0.76 to 1.09).

AUTHORS' CONCLUSIONS

We found no evidence to support antioxidant supplements for primary or secondary prevention. Vitamin A, beta-carotene, and vitamin E may increase mortality. Future randomised trials could evaluate the potential effects of vitamin C and selenium for primary and secondary prevention. Such trials should be closely monitored for potential harmful effects. Antioxidant supplements need to be considered medicinal products and should undergo sufficient evaluation before marketing.

Meta-analysis: antioxidant supplements for primary and secondary prevention of colorectal adenoma

BACKGROUND

Colorectal cancer may be prevented by reducing the development of adenomatous polyps.

AIM

To assess the benefits and harms of antioxidant supplements in preventing colorectal adenoma.

METHODS

Using the Cochrane Collaboration methodology we reviewed all randomized clinical trials comparing antioxidant supplements with placebo or no intervention. We searched electronic databases and the reference lists until October 2005. Outcome measures were development of colorectal adenoma adverse events. We analysed dichotomous outcomes with fixed- and random-effects model meta-analyses and calculated the relative risk with 95% confidence interval.

RESULTS

We identified eight randomized trials (17 620 participants). Neither fixed-effect (relative risk: 0.93, 95% CI: 0.81-1.1) nor random-effect model meta-analyses (0.82, 0.60-1.1) showed statistically significant effects of supplementation with beta-carotene, vitamins A, C, E and selenium alone or in combination. Antioxidant supplements seemed to increase the development of colorectal adenoma in three low-bias risk trials (1.2, 0.99-1.4) and significantly decrease its development in five high-bias risk trials (0.59, 0.47-0.74). The estimates difference is significant (P < 0.0001). There was no significant difference between the intervention groups regarding adverse events, including mortality (0.82, 0.47-1.4).

CONCLUSION

We found no convincing evidence that antioxidant supplements have significant beneficial effect on primary or secondary prevention of colorectal adenoma.

Targeting of autonomous parvoviruses to colon cancer by insertion of Tcf sites in the P4 promoter

The Wnt signaling pathway is activated by mutations in the adenomatous polyposis coli (APC) or beta-catenin genes in most colon cancers, leading to the transactivation of promoters containing binding sites for the Tcf/LEF family of transcription factors. We have previously shown that it is possible to confer colon cancer specificity on autonomous parvoviruses by inserting Tcf sites into the viral P4 promoter. The mutant Tcf promoters were responsive to activation of the Wnt pathway but the viruses replicated poorly. We show here that reduction of the number of Tcf sites from four to two leads to an increase in the efficiency of replication and toxicity of the viruses in Co115 colon cancer cells, with only a small reduction in selectivity for cells with an active Wnt signaling pathway. Despite this improvement, virus production by most colon cancer cells remained low. Analysis of parental phH1 virus infection of SW480 colon cancer cells showed that the nonstructural and capsid proteins were expressed, but single stranded DNA and progeny virus were not produced. This defect reflects the dependence of autonomous parvoviruses on host functions for many steps in their replication cycle and represents a major limitation to the use of selectively replicating parvoviruses for colon cancer therapy.

Antioxidant supplements for preventing gastrointestinal cancers

BACKGROUND

Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

SEARCH STRATEGY

We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 1, 2003), MEDLINE, EMBASE, LILACS, and SCI-EXPANDED from inception to February 2003, and The Chinese Biomedical Database (March 2003). We scanned reference lists and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing antioxidant supplements to placebo/no intervention examining the incidence of gastrointestinal cancers.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion and extracted data. The outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on fixed and random effects meta-analyses.

MAIN RESULTS

We identified 14 randomised trials (170,525 participants), assessing beta-carotene (9 trials), vitamin A (4 trials), vitamin C (4 trials), vitamin E (5 trials), and selenium (6 trials). Trial quality was generally high. Heterogeneity was low to moderate. Neither the fixed effect (RR 0.96, 95% CI 0.88 to 1.04) nor random effects meta-analyses (RR 0.90, 95% CI 0.77 to 1.05) showed significant effects of supplementation with antioxidants on the incidences of gastrointestinal cancers. Among the seven high-quality trials reporting on mortality (131,727 participants), the fixed effect (RR 1.06, 95% CI 1.02 to 1.10) unlike the random effects meta-analysis (RR 1.06, 95% CI 0.98 to 1.15) showed that antioxidant supplements significantly increased mortality. Two low-quality trials (32,302 participants) found no significant effect of antioxidant supplementation on mortality. The difference between the mortality estimates in high- and low-quality trials was significant by test of interaction (z = 2.10, P = 0.04). Beta-carotene and vitamin A (RR 1.29, 95% CI 1.14 to 1.45) and beta-carotene and vitamin E (RR 1.10, 95% CI 1.01 to 1.20) significantly increased mortality, while beta-carotene alone only tended to do so (RR 1.05, 95% CI 0.99 to 1.11). Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In four trials (three with unclear/inadequate methodology), selenium showed significant beneficial effect on gastrointestinal cancer incidences.

REVIEWERS' CONCLUSIONS

We could not find evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, they seem to increase overall mortality. The potential cancer preventive effect of selenium should be studied in adequately conducted randomised trials.

[Large uterine myoma during pregnancy and delivery - choice of management]

There are scanty of available data about the management of myoma of the uterus during pregnancy and birth. The authors describe two cases of such a pathology--big myoma of the uterus > 10 sm diameter (d.), who were treated conservatively and ended successfully, without serious complications. The pregnant women were done cesarean section and during the operation the myomas were excisiert. There were no complications intra- and postoperationem. The authors suggest that myectomy during pregnancy and cesarean section must not be don routinely.

Randomized clinical trials in HEPATOLOGY: predictors of quality

Evidence shows that the quality of randomized clinical trials (RCTs) affects estimates of intervention efficacy, which is significantly exaggerated in low-quality trials. The present study examines the quality of all 235 RCTs published in HEPATOLOGY from the initiation in 1981 through August 1998. Quality was assessed by means of a validated 5-point scale and separate quality components associated with empirical evidence of bias. Only 26% of all RCTs reported sample size calculations, 52% adequate generation of the allocation sequence, 34% adequate allocation concealment and 34% double-blinding. The median quality score of all trials was 3 points (range, 1-5 points). Multiple logistic regression analysis explored the association between quality and therapeutic areas, number of centers, external funding, year of publication, and country of origin. High-quality trials were most likely to investigate portal hypertension (odds ratio [OR]: 2.4; 95% CI: 1.1-5.5; P =.03), be multicentered (OR: 3.4; 95% CI: 1.3-8.9; P =.01), sponsored by public organizations (OR: 4.2; 95% CI: 2.1-8.6; P =.0001), or the drug and device industry (OR: 4.7; 95% CI: 2.2-10.2; P =.0001) compared with other therapeutic areas, single-center trials, and trials with no external funding. Quality did not improve with time and was not associated with country of origin. The main conclusions are that the quality of RCTs in HEPATOLOGY needs improvement and that the probability of high quality increased with the number of centers involved and external funding.

Quality assessment of reports on clinical trials in the Journal of Hepatology

BACKGROUND/AIMS

Electronic searches on databases for randomised clinical trials and controlled clinical trials do not identify as many trials as handsearches, and trial reporting may be flawed. The aims were to identify all fully reported randomised clinical trials in the Journal of Hepatology and to make a qualitative assessment of the reporting.

METHODS

The publications were identified by systematically handsearching the full text of the journal and searching MEDLINE. Central dimensions of trial quality were used to assess the reporting quality of the trials.

RESULTS

Randomised clinical trials represented 8.4% of the original articles (171/2028). Ten original articles (0.5%) could not be classified. A search on MEDLINE identified 81.3% of the randomised clinical trials, i.e., 139 out of the 171 identified by the handsearch. A total of 166 randomised clinical trials could be quality assessed. Forty-seven (28.3%) of them reported adequate generation of allocation sequence; 22 (13.3%) adequate allocation concealment; 95 (57.2%) allowed intention-to-treat analysis with only a few losses to follow-up; 50 (30.1%) were double-blind; 33 (19.9%) reported sample-size calculations; 13 trials (7.8%) employed the crossover design; and the median number of subjects per intervention arm in parallel group trials was 19 subjects (interquartile range: 11-31; range: 5-519). The quality of reporting was significantly better in regular issue articles than in supplement articles.

CONCLUSIONS

Many important randomised clinical trials are published in the Journal of Hepatology, but there seems to be ample room for improvement of quality of reporting.

A novel thermostable inhibitor of trypsin and subtilisin from the seeds of Brassica nigra: amino acid sequence, inhibitory and spectroscopic properties and thermostability

A novel thermostable protein inhibitor of trypsin and subtilisin, called BN, was isolated from the seeds of Brassica nigra. The purified protein gave a single band on SDS-PAGE, corresponding to a molecular mass of 15 500 +/- 1000 Da. The inhibitor is composed of two disulfide-linked polypeptide chains, consisting of 39 and 90 residues, respectively. The amino acid sequence of the two chains was determined by Edman degradation of peptides, isolated from enzyme hydrolysates with TPCK-trypsin, EndoLysC proteinase and a Glu-specific proteinase of reduced and vinylpyridinated protein samples. A segment of the 'heavy' chain, between residues 65 and 81, showed homology with the reactive site loop region of the 6-kDa trypsin inhibitors from Nicotiana alata. The basic residue in position 39 (N. alata) or 70 (napins) is conserved as arginine or lysine in all inhibitors from N. alata and in all napins hitherto sequenced. Probably, the two families of trypsin inhibitors have structurally similar reactive sites. BN exhibits an extremely high thermostability: CD measurements showed that during heating to 97 degrees C it preserves a considerable part of the polypeptide backbone folding. Studies on the fluorescence properties of the inhibitor BN in the absence and presence of neutral or ionic quenchers demonstrated that the intrinsic emission of this protein is dominated by a tryptophyl residue, buried in the interior of the protein matrix. 20% of the light absorbed by Tyr 63 of the 'heavy' chain is transferred to Trp 26 of the 'light' chain.