Neuregulin 3 does not confer risk for schizophrenia and smooth pursuit eye movement abnormality in a Korean population

Located on chromosome 10q22-q23, the human neuregulin3 (NRG3) is considered to be a strong positional and functional candidate gene for schizophrenia pathogenesis. Several case-control studies examining the association of polymorphisms in NRG3 with schizophrenia and/or related traits such as delusion have been reported recently in cohorts of Han Chinese, Ashkenazi Jews, Australians and white Americans of Western European ancestry. Thus, this study aimed to comprehensively investigate the association of NRG3 genetic variations with the risk of schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Using TaqMan assay, six single-nucleotide polymorphisms (SNPs) in the intronic region of NRG3 were genotyped and two major haplotypes were identified in 435 patients with schizophrenia as cases and 393 unrelated healthy individuals as controls. A total of 113 schizophrenia patients underwent an eye tracking task, and degree of SPEM abnormality was measured using the logarithmic values of the signal/noise (Ln S/N) ratio. Differences in frequency distributions were analyzed using logistic and regression models following various modes of genetic inheritance and controlling for age and sex as covariates. Subsequent analysis revealed that the frequency distributions of NRG3 polymorphisms and haplotypes were similar between schizophrenia patients and healthy controls of Korean ethnicity. Furthermore, no significant differences were observed between the genetic variants tested for SPEM abnormality. By elucidating a lack of association in a Korean population, findings from this study may contribute to the understanding of the genetic etiology focusing on the role of NRG3 in schizophrenia pathogenesis.

Controlling the phase of a light beam with a single molecule

We employ heterodyne interferometry to investigate the effect of a single organic molecule on the phase of a propagating laser beam. We report on the first phase-contrast images of individual molecules and demonstrate a single-molecule electro-optical phase switch by applying a voltage to the microelectrodes embedded in the sample. Our results may find applications in single-molecule holography, fast optical coherent signal processing, and single-emitter quantum operations.

Gefitinib, cisplatin, and concurrent radiotherapy for locally advanced head and neck cancer: EGFR FISH, protein expression, and mutational status are not predictive biomarkers

BACKGROUND

Gefitinib was demonstrated to be synergistic with cisplatin and radiotherapy (RT) in in vitro studies. Biomarkers predictive of response to gefitinib in squamous cell head and neck cancer is still lacking.

METHODS

Thirty-one patients with locally advanced and easily accessible primary tumor sites for biopsies were recruited. Gefitinib was started 3 weeks before the start of cisplatin/concurrent radiotherapy (CTRT) and continued during the CTRT phase and thereafter for 4 months as consolidation phase. Two baselines and a repeat tumor sample were taken after 2 weeks of gefitinib alone to study its impact on tumor gene expression. Epidermal growth factor receptor (EGFR) protein expression, FISH and mutational status, and matrix metallopeptidase 11 (MMP11) protein expression were correlated with response and survival outcome.

RESULTS

The overall response rate to gefitinib alone was 9.7%. The survival outcome is as follows: median disease free 1.3 years, median survival time 2.4 years, 3-year disease free 42.9%, and 3-year overall survival 48.4%. EGFR FISH, protein expression, and mutational status did not predict for response nor survival outcome of patients. Although MMP11 overexpression did not predict for response, it predicted significantly for a poorer survival outcome.

CONCLUSIONS

Gefitinib can be combined safely with cisplatin/RT. More studies are needed to uncover predictive biomarkers of benefit to gefitinib.

CBP80-promoted mRNP rearrangements during the pioneer round of translation, nonsense-mediated mRNA decay, and thereafter

In mammalian cells, two different messenger ribonucleoproteins (mRNPs) serve as templates for protein synthesis. Newly synthesized mRNPs bound by the cap-binding protein heterodimer CBP80-CBP20 (CBC) initially undergo a pioneer round of translation. One purpose of this round of translation is to ensure the quality of gene expression, as exemplified by nonsense-mediated messenger RNA (mRNA) decay (NMD). NMD largely functions to eliminate mRNAs that prematurely terminate translation, although NMD also contributes to proper gene control, and it targets CBC-bound mRNPs. CBC-bound mRNPs are remodeled to eukaryotic translation initiation factor (eIF)4E-bound mRNPs in steps that (1) are a consequence of the pioneer round of translation and (2) occur independently of translation. Rather than supporting NMD, eIF4E-bound mRNPs provide for the bulk of cellular protein synthesis and are the primary targets of mRNA decay mechanisms that conditionally regulate gene expression. Here, we overview cellular processes by which CBC-bound mRNPs are remodeled to eIF4E-bound mRNPs. We also describe the molecular movements of certain factors during NMD in view of the influential role of CBP80.

Predictors of hepatitis B screening among patients with cancer

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Background: Patients with hepatitis B virus (HBV) infection are at risk of reactivation after chemotherapy. It is unclear whether all patients or only those with certain risk factors should be screened for HBV before chemotherapy. The purpose of our study was to determine the clinical predictors of HBV screening in a single institution.

Methods: In this retrospective, cross-sectional study, we evaluated new patients who received chemotherapy between 1/1/04 and 9/30/07. We collected data on patients' demographics, types of cancer and chemotherapy, and HBV risk factors such as a previous ICD-9 code for hepatitis C or other liver conditions. We searched for HBV screening as defined by an HBsAg or anti-HBc test ordered prior to chemotherapy. In univariate analyses, we examined the association between each of the patient-related variables and HBV screening. We then determined predictors of HBV screening in a multivariable logistic regression model.

Results: We found 10,729 patients who had chemotherapy during the study period. Overall, 16.7% had HBV screening. All of the following predictors in the univariate analysis were significant for HBV screening at the p<0.01 level: age, gender, ethnicity, U.S. residence, cancer type, chemotherapy type, and having a HBV risk factor. In multivariable logistic regression examining predictors for screening using HBsAg, we found that Asian ethnicity (OR 1.75; 1.16-2.66), hematologic malignancies (OR 22.65; 19.3-26.31), and the receipt of rituxamab (OR 3.71; 3.03-4.48) were significant predictors at the p<0.01 level. Women were less likely to be screened than men (OR 0.68; 0.59-0.78). We repeated the analyses using the anti-HBc screening test, and the results were similar. Overall, 1.5% of the screened patients had a positive HBV test.

Conclusions: We found that ethnicity, cancer types, and chemotherapy drugs predict physician-driven HBV screening. Future research is needed to study the predictors of a positive HBV screening test and reactivation of HBV after chemotherapy.

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Far-infrared conductivity measurements of pair breaking in superconducting Nb 0.5 Ti 0.5 N thin films induced by an external magnetic field

We report the complex optical conductivity of a superconducting thin film of Nb 0.5 Ti 0.5 N in an external magnetic field. The field was applied parallel to the film surface and the conductivity extracted from far-infrared transmission and reflection measurements. The real part shows the superconducting gap, which we observe to be suppressed by the applied magnetic field. We compare our results with the pair-breaking theory of Abrikosov and Gor'kov and confirm directly the theory's validity for the optical conductivity.

Phase II trial of sagopilone, a novel epothilone analog in metastatic melanoma

BACKGROUND

Sagopilone is a novel fully synthetic epothilone with promising preclinical activity and a favourable toxicity profile in phase I testing.

METHODS

A phase II pharmacokinetic and efficacy trial was conducted in patients with metastatic melanoma. Patients had measurable disease, Eastern Cooperative Oncology Group performance status 0-2, adequate haematological, and organ function, with up to 2 previous chemotherapy and any previous immunotherapy regimens. Sagopilone, 16 mg m⁻², was administered intravenously over 3 h every 21 days until progression or unacceptable toxicity.

RESULTS

Thirty-five patients were treated. Sagopilone showed multi-exponential kinetics with a mean terminal half-life of 64 h and a volume of distribution of 4361 l m⁻² indicating extensive tissue/tubulin binding. Only grade 2 or lower toxicity was observed: these included sensory neuropathy (66%), leukopenia (46%), fatigue (34%), and neutropenia (31%). The objective response rate was 11.4% (one confirmed complete response, two confirmed partial responses, and one unconfirmed partial response). Stable disease for at least 12 weeks was seen in an additional eight patients (clinical benefit rate 36.4%).

CONCLUSION

Sagopilone was well tolerated with mild haematological toxicity and sensory neuropathy. Unlike other epothilones, it shows activity against melanoma even in pretreated patients. Further clinical testing is warranted.