The evaluation of drug rechallenge: the casopitant Phase III program

Drug rechallenge (or reinitiation), following an event of drug-induced liver injury, is associated with 13% mortality in prospective series. Rechallenge generally results in much more rapid injury than the initial liver event. The neurokinin-1 antagonist casopitant or its placebo was administered cyclically with ondansetron and dexamethasone in two randomized chemotherapy-induced nausea and vomiting clinical trials in nearly 3000 subjects. Grade 3 ALT elevations were observed in up to 2% of subjects receiving casopitant or placebo treatment. Similar rates of positive rechallenge were observed in the casopitant 8/29 (28%) and placebo groups 2/8 (25%), with no Grade 4 ALT elevations, hypersensitivity or liver-related serious adverse events. Publishing available rechallenge data (positive and negative) will advance our clinical understanding. Rechallenge should only be considered when the potential drug benefit exceeds the risk.     

Glutathione S-transferase and microsomal epoxide hydrolase gene polymorphisms and risk of chronic obstructive pulmonary disease in Slovak population

Aim

To determine the risk of chronic obstructive pulmonary disease (COPD) associated with polymorphisms in the glutathione S-transferase (GST) M1, GST T1, and microsomal epoxide hydrolase (EPHX1) genes in a cohort of Slovak population.

Methods

Two hundred and seventeen patients with the diagnosis of COPD and 160 control subjects were enrolled in the study. Blood samples were collected from all subjects and the DNA from peripheral blood lymphocytes was used for subsequent genotyping assays, using polymerase chain reaction and restriction fragment-length polymorphism methods.

Results

In an unadjusted model, an increased risk for COPD was observed in subjects with EPHX1 His113-His113 genotype (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.20-4.69; P = 0.008), compared with the carriers of the Tyr113 allele. However, after the adjustments for age, sex, and smoking status, the risk was not significant (adjusted OR, 1.79; 95% CI, 0.91-3.53; P = 0.093). In a combined analysis of gene polymorphisms, the genotype combination EPHX1 His113-His113/GSTM1 null significantly increased the risk of COPD in both, unadjusted (OR, 5.08; 95% CI, 1.70-20.43; P = 0.001) and adjusted model (OR, 4.87; 95% CI, 1.57-15.13; P = 0.006).

Conclusion

Although none of the tested gene polymorphisms was significantly related to an increased risk of COPD alone, our results suggest that the homozygous exon 3 mutant variant of EPHX1 gene in the combination with GSTM1 null genotype is a significant predictor of increased susceptibility to COPD in the Slovak population. The findings of the present study emphasize the importance of detoxifying and antioxidant pathways in the pathogenesis of COPD.Chronic obstructive pulmonary disease (COPD) represents a major public health care problem worldwide due to its increasing prevalence, morbidity, and mortality (1). Generally, COPD is characterized by progressive and only partially reversible airflow limitation (2). Although cigarette smoking is the most important risk factor for COPD, only 20%-30% of chronic smokers develop severe impairment of lung function associated with COPD (3). Besides smoking, other environmental and genetic factors and gene-environment interactions influence the development of COPD (4).Severe α-1-antitrypsin deficiency is a well established genetic risk factor for COPD that has provided a basis for the protease-antiprotease hypothesis in the pathogenesis of COPD (5,6). Other candidate genes that might play a role in the development of COPD are involved in endogenous protease/antiprotease imbalance, inflammatory processes, metabolism of mutagens and carcinogens in tobacco smoke, and in mucocilliary clearance (7). Interindividual differences in the polymorphisms of enzymes metabolizing the xenobiotic substances and free radicals contained in the cigarette smoke may play a role in the individual susceptibility to the decrease in lung functions in smokers (8).Microsomal epoxide hydrolase (EPHX1) is generally considered to be a protective enzyme involved in the defense from oxidative damage (9,10). Two common polymorphic sites in the EPHX1 gene that influence the enzyme activity can be detected (11). An exon 3 thymine-to-cytosine mutation changes Tyr residue 113 to His, thus reducing the enzyme activity by about 50%. The second mutation, an adenine-to-guanine transition in exon 4 of the gene, changes His residue 139 to Arg and results in the production of EPHX1 with the activity increased by about 25% (11). The combination of these polymorphisms leads to a formation of several functional phenotypes of EPHX1. The slow metabolizing type of EPHX1 was associated with emphysema and COPD (9). In another study, an association of slow metabolizing EPHX1 phenotype with an accelerated deterioration of lung function in smokers was observed (12). In addition, several studies conducted in different populations have suggested that the EPHX1 genotype may influence individual susceptibility to COPD (9,13-15). Nevertheless, other investigators failed to confirm an association between the EPHX1 gene polymorphisms and COPD (16-18).Glutathione S-transferases (GST) play a role in the detoxification of carcinogenic compounds contained in cigarette smoke and in the antioxidant protection (19,20). Recently, the GSTM1 and the GSTT1 gene polymorphisms have been excessively studied with respect to their potential contribution to the risk of COPD (8,17,21,22). The deficiency in the activity of GSTM1 and GSTT1 enzymes is caused by the inherited homozygous absence of the GSTM1 or GSTT1 gene, respectively (ie, GSTM1 null or GSTT1 null genotype). Previously, the homozygous GSTM1 null genotype has been associated with lung cancer (23), emphysema (21), and reductions in the lung function in Caucasian smokers with non-small-cell lung cancer (22). However, another study conducted in Koreans found no differences in the frequencies of polymorphic genotypes of GSTM1 and GSTT1 genes between patients with COPD and healthy smokers (17).Since current data on the potential associations between an increased COPD risk and genes encoding the enzymes metabolizing xenobiotic substances are inconsistent, the aim of our study was to analyze the relation between COPD and gene polymorphisms of EPHX1, GSTM1, and GSTT1 genes in a sample of Slovak population.     

Biphasic alveolosquamoid renal carcinoma: a histomorphological,immunohistochemical, molecular genetic,and ultrastructural study of a distinctive morphologic variant of renal cell carcinoma

Only a few cases of sarcomatoid renal cell carcinomas (RCCs) with squamous differentiation have been published. We present 2 RCCs exhibiting a hitherto not reported biphasic neoplastic cell population exhibiting a predominantly alveolar architecture where squamoid differentiation was identified in one of the neoplastic cell populations. None of the tumors showed chromophobe features or any evidence of sarcomatoid transformation. The tumors arose in 2 adult patients and were characterized by routine histology, immunohistochemistry, ultrastructure, array comparative genomic hybridization, confirmatory fluorescent in situ hybridization, and loss of heterozygosity analysis. Tumors measured 3 and 4 cm and were located within the renal parenchyma and had no pelvicalyceal connection. Both tumors were composed of a distinctly dual-cell population. The larger tumor cells displayed squamoid features and formed round well-demarcated solid alveolated islands that, in large parts, were surrounded by a smaller neoplastic cell component. The squamoid cells were immunoreactive for cytokeratins (CKs) (AE1-AE3, Cam 5.2, CK5/6, CK7, and CK20), epithelial membrane antigen, racemase/AMACR, and carboanhydrase IX (in 1 case focally). The small cell population was positive for CK7, epithelial membrane antigen, and racemase/AMACR, whereas CK20, AE1-3, and carboanhydrase IX were negative. CD10 was focally positive in the large squamoid cells in 1 case. Cathepsin K, E-cadherin, and CD117 displayed focal positivity in 1 case. Vimentin, RCC marker, parvalbumin, S100 protein, S100 A1, p63, p53, CDX2, uroplakin III, HMB45, TFE3, WT1, synaptophysin, chromogranin A, thyroglobulin, and TTF1 were negative. The proliferative activity (Ki-67) was low (1%) in the small cell component in both cases, whereas the large neoplastic tumor cells displayed a significantly higher proliferation (20%-35%). Ultrastructurally, desmosomes and tonofilaments were identified in the large tumor cells, confirming squamoid differentiation in a subset of tumor cells. Array comparative genomic hybridization of 1 analyzable case (confirmed with fluorescent in situ hybridization and loss of heterozygosity analysis) revealed partial or complete losses of chromosomes 2, 5, 6, 9, 12, 15, 16, 17, 18 and 22, (including biallelic loss of CDKN2A locus) and partial gains of chromosomes 1, 5, 11, 12 and 13. Follow-up at 6 years showed no recurrence or metastasis in 1 patient. The other (male) patients had a subcutaneous metastasis at presentation, but during a 1-year follow-up no evidence of recurrence or further metastatic events have been documented. Our data indicate that biphasic alveolosquamoid renal carcinoma is a unique and distinctive tumor. The large squamoid and small tumor cells have overlapping but still distinctive immunohistochemical patterns of protein expression. Multiple chromosomal aberrations were identified, some of them located in regions with known tumor suppressor genes and oncogenes.     

Closed tube method for rapid screening of IL28B polymorphisms involved in response to hepatitis C treatment

Background &; aimHepatitis C is a liver disease caused by the hepatitis C virus. Interferon and ribavirin combination therapy has been a standard treatment of chronic hepatitis C. But only about 50% of patients have positive response to treatment and achieve so called sustained virological response. Recent studies indicate association of several single nucleotide polymorphisms near IL28B gene and response of hepatitis C patients to combined interferon/ribavirin treatment. In this study, rapid, specific and cost-effective small amplicon genotyping method for the two clinically important polymorphisms, rs12979860 C > T and rs8099917 T > G, near the IL28B gene is described.MethodsThe distribution of genotypes of 181 HCV-uninfected Slovak Caucasians was analyzed using this novel method, based on a real-time melting analysis of the small amplicon.Results and conclusionsThe frequency of wild-type (TT) homozygotes for rs8099917 was 66.30%, frequency of heterozygotes (TG) was 30.94% and we found only 2.76% subjects homozygous for risk G allele (allelic frequencies: T = 81.77%, G = 18.23%) were found. The frequency of wild-type genotype (CC) for rs12979860 was 49.72%, frequencies of heterozygous (CT) and risk-allele homozygous genotypes (TT) were 39.78% and 10.50%, respectively (allele frequencies: C = 69.61%, T = 30.39%). Statistically significant differences in the distribution of the alleles between the men and the women were not found. The novel method developed in our laboratory proved to be simple and highly customizable.     

Rubella revisited: where are we on the road to disease elimination in Central Europe?

Rubella is a contagious viral disease with few complications except when contracted by pregnant women. Rubella infection in pregnancy can result in miscarriage, stillbirth or an infant born with congenital rubella syndrome (CRS) which comprises deafness, heart disease, cataracts and other permanent congenital manifestations. Clinical diagnosis of rubella is difficult due to overlapping symptoms with many other diseases and confirmation of rubella is not possible without laboratory testing.Effective vaccination programmes are critical to the elimination of rubella and prevention of CRS. Such programmes have been successful in several countries in Europe and around the world. However, rubella outbreaks still occur due to suboptimal vaccine coverage and in the past 10 years rubella has been reported in Central European countries such as Romania and Poland. Over the past decade the elimination of rubella and prevention of congenital rubella infection in Europe has been a high priority for the WHO European Regional Office. In 2010 the WHO regional committee for Europe renewed its commitment to the elimination of rubella and prevention of CRS with a new target of 2015.This paper examines the current situation for rubella and CRS in Central Europe and describes the different rubella vaccination programmes in the region. The Central European Vaccination Advisory Group (CEVAG) recommends that two doses of measles, mumps and rubella vaccine, MMR, should be given to all children. The first dose should be given between 12 and 15 months of age. The second dose can be given between the ages of 21 months and 13 years with the exact age of administration of the second dose depending on the situation specific to each country. All suspected rubella cases should be laboratory-confirmed and monitoring systems to detect and investigate cases of CRS should be strengthened.     

Corrosion Behavior of Zn,Fe and Fe-Zn Powder Materials Prepared via Uniaxial Compression

Powder metallurgy is one of the most prevalent ways for metallic degradable materials preparation. Knowledge of the properties of initial powders used during this procedure is therefore of great importance. Two different metals, iron and zinc, were selected and studied in this paper due to their promising properties in the field of biodegradable implants. Raw powders were studied using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDX). Powders (Fe, Zn and Fe-Zn in a weight ratio of 1:1) were then compressed at the pressure of 545 MPa to the form of pellets with a diameter of 1.7 cm. Surface morphology and degradation behavior in the Hanks´ solution were studied and evaluated. Electrochemical polarization tests along with the static immersion tests carried out for 21 days were employed for corrosion behavior characterization. The highest corrosion rate was observed for pure Zn powder followed by the Fe-Zn and Fe, respectively. A mixed Fe-Zn sample showed similar properties as pure zinc with no signs of iron degradation after 21 days due to the effect of galvanic protection secured by the zinc acting as a sacrificial anode.     

The assessment of intracranial dynamics by transcranial Doppler sonography in perioperative period in paediatric hydrocephalus

Purpose

To evaluate Doppler parameters of anterior cerebral artery (ACA) and relationship to morphological parameters of cerebral ventricles and periventricular brain tissue in paediatric hydrocephalus before and after drainage procedure.

Methods

Forty newborns with hydrocephalus were evaluated before and after the drainage procedure. The morphological parameters of brain (ventricular index, width of ventricles, haemorrhagic lesions, asymmetric ventricular dilatation and dynamics of ventricles) were measured by transcranial ultrasonography. The haemodynamic parameters of ACA (peak systolic blood flow velocity, end-diastolic blood flow velocity and resistance index/RI/) were evaluated by Doppler ultrasonography. The correlation between morphological and haemodynamic parameters was analysed.

Results

We found significant decrease of ventricular dilatation, which was accompanied with significant decrease of basal and compressive RI-ACA after drainage procedure. The correlation between basal RI-ACA, compressive RI-ACA and the dynamics of ventricular dilatation was not significant before and after drainage operation, as well. The significant correlation between preoperative basal RI-ACA, postoperative compressive RI-ACA and asymmetry of cerebral ventricles was confirmed. Statistical analysis showed significant correlation between basal RI-ACA, compressive RI-ACA and haemorrhagic lesions after drainage operation.

Conclusions

The results of our study showed the alteration of Doppler parameters of cerebral circulation in newborns with hydrocephalus before the drainage procedure. The successful drainage operation leads to the improvement of haemodynamic parameters of cerebral circulation. However, the statistical analysis showed the influence of some intracranial factors—the asymmetry of dilatation of lateral cerebral ventricles and periventricular haemorrhagic lesions on the Doppler parameters of cerebral circulation.