COMT rs4680 Met is not always the 'smart allele': Val allele is associated with better working memory and larger hippocampal volume in healthy Chinese

Catechol-O-methyltransferase (COMT) Val158Met (rs4680) polymorphism plays a crucial role in regulating brain dopamine level. Converging evidence from Caucasian samples showed that, compared with rs4680 Val allele, the Met allele was linked to lower COMT activity, which in turn was linked to better cognitive performance such as working memory (WM) and to a larger hippocampus (a brain region important for WM). However, some behavioral studies have shown that the function of rs4680 appears to vary across different ethnic groups, with Chinese subjects showing an opposite pattern as that for Caucasians (i.e. the Val allele is linked to better cognitive functions related to WM in Chinese). Using a sample of healthy Han Chinese college students (ages from 19 to 21 years), this study investigated the association of COMT Val158Met genotype with behavioral data on a two-back WM task (n = 443, 189M/254F) and T1 MRI data (n = 320, 134M/186F). Results showed that, compared to the Met allele, the Val allele was associated with larger hippocampal volume (the right hippocampus: β = -0.118, t = -2.367, P = 0.019, and the left hippocampus: β = -0.099, t = -1.949, P = 0.052) and better WM performance (β = -0.110, t = -2.315, P = 0.021). These results add to the growing literature on differentiated effects of COMT rs4680 polymorphism on WM across populations and offer a brain structural mechanism for such population-specific genetic effects.

Activation of glucagon-like peptide-1 receptor inhibits tumourigenicity and metastasis of human pancreatic cancer cells via PI3K/Akt pathway

AIMS

It has been reported that glucagon-like peptide-1 (GLP-1) agents are associated with an increased risk of pancreatic cancer in patients with type 2 diabetes. Reports have indicated that GLP-1 promotes pancreatic metaplasia and premalignant lesions. The aims of this study were to determine the effects of GLP-1-based therapy on pancreatic cancer cells.

METHODS

Immunohistochemistry was used to investigate GLP-1 receptor (GLP-1R) expression in 30 human pancreatic cancer tissues. We also analysed associated clinicopathological data and each patient's prognosis. Two human pancreatic cancer cell lines were used to evaluate the in vitro effects of the GLP-1R agonist liraglutide on cell growth, migration and invasion. Mouse xenograft models of human pancreatic cancer were established to evaluate the effects of liraglutide in vivo.

RESULTS

Human pancreatic cancer tissues showed lower levels or a lack of GLP-1R expression when compared with levels in the tumour-adjacent pancreatic tissues. Negative GLP-1R expression occurred more frequently in advanced tumours with larger diameters and lymphatic metastasis, and was associated with a poor prognosis. GLP-1R activation with liraglutide inhibited tumourigenicity and metastasis of human pancreatic cancer cells in vitro and in vivo. Akt activation was dose-dependently inhibited by liraglutide, and the PI3K inhibitors, LY294002 and wortmannin, displayed similar suppressive effects to liraglutide in human pancreatic cancer cells.

CONCLUSIONS

GLP-1R activation has an antitumour effect on human pancreatic cancers via inhibition of the PI3K/Akt pathway. This finding suggests that GLP-1-based therapies may be beneficial, rather than harmful, in treating type 2 diabetic patients with pancreatic cancer.

Detection of cervical metastatic lymph nodes in papillary thyroid carcinoma by Fourier transform infrared spectroscopy

Background

A previous study demonstrated that Fourier transform infrared (FTIR) spectroscopy can distinguish thyroid cancer from benign thyroid lesions. The aim of this study was to explore the use of FTIR for identifying metastatic lymph nodes of papillary thyroid cancer in vitro, and distinguishing between metastatic and non-metastatic tissue.

Methods

Some 184 freshly removed cervical lymph nodes were obtained from 22 patients with papillary thyroid cancer undergoing thyroid surgery with lymph node dissection. Samples were measured by FTIR spectroscopy before being processed for histopathological diagnosis. The FTIR spectrum of each sample identified 13 bands from 1000 to 4000 cm−1. The peak position, intensity and full width at half maximum of each absorbent band were measured, and the relative intensity ratios were calculated. The FTIR spectra of metastatic lymph nodes were compared with those of non-metastatic nodes, and a linear discriminant analysis was performed based on these data.

Results

Histopathological examination confirmed 61 metastatic and 123 non-metastatic lymph nodes. The FTIR parameters of metastatic and non-metastatic lymph nodes differed owing to the content or configuration alterations of nucleic acids, proteins, lipids and carbohydrates. The sensitivity for FTIR in diagnosing metastatic lymph nodes was 80·3 per cent, the specificity was 91·9 per cent and the accuracy was 88·0 per cent.

Conclusion

FTIR spectroscopy is a novel technique for detection of metastatic lymph nodes and may prove useful in surgery for papillary thyroid cancer.

Simplified method of heterotopic rat heart transplantation using the cuff technique: application to sublethal dose protocol of methotrexate on allograft survival

Rodent heterotopic heart transplantation (HHT) models have been developed for the study of transplantation immunology. Most of these transplantations are performed by hand-suture techniques, requiring several months of training. We describe a modified technique of rat HHT in the neck, using a cuff method that can be mastered by beginners within a few weeks. Our main modification of the rat HHT in the neck is that the right superior vena cava of the graft is chosen as an outflow duct, while the pulmonary artery has been taken as an effluent drainage in the ordinary HHT models. The aorta of the donor is anastomosed with the carotid artery of the recipient. Donation can be completed within 5 min and vascular connections in the recipient done within 3 min, resulting in a minimum of ischemia time. Using this minimum surgical intervention model, we tested the immunosuppressive effect of a sublethal dose of methotrexate (MTX), which has been widely used in cancer therapy. Our results showed that high doses of MTX severely suppressed the recipient bone marrow, but prolonged heart allografts for more than 365 days after HHT. In conclusion, the new model simplified the rat HHT procedure and made it possible for the beginner of rodent transplantation to master this skill within a few weeks. Using this minimized intervention technique, we found that the high doses of MTX can significantly prolong the survival of fully mismatched DA heart graft in PVG/c recipient.

Liver Transplant With Portocaval Hemitransposition: Blood Supply With Only Hepatic Artery Is Possible?

We present herein a case of orthotopic liver transplantation (OLT) with portocaval hemitransposition. The patient underwent OLT for hepatocellular carcinoma with diffused portomesenteric vein thrombosis. The unique feature of this case was that 6 months after the operation, because of recurrent carcinoma, the hepatic vein was occluded and the portal vein became the drainage vein and the hepatic artery was the only vessel that supplied the liver. Yet the patient survived. Regarding the unique hemodynamic changes of the patient, could we let the portal vein alone in case of diffuse portomesenteric thrombosis in OLT?

Students’ Value Orientations in Contemporary China: Analysis of Measurement Invariance and Latent Mean Differences in Comparison With Students From Germany and Russia

The present study examined Chinese students’ personal value orientations according to the Schwartz value theory in comparison with students from Germany and Russia. The theory postulates 10 value orientations grouped into four higher-order factors: conservation versus openness to change and self-transcendence versus self-enhancement. Schwartz’ value orientations have been extensively investigated in Europe but less in East Asian countries such as China. We hypothesized that Chinese students would score higher on conservation and self-enhancement than German and Russian students, but lower on self-transcendence. Regarding openness to change, a null hypothesis was formulated. Students from China ( n = 9,601), Germany ( n = 1,118), and Russia ( n = 3,890) completed the Portrait Values Questionnaire (PVQ-21). To ensure methodological preconditions for cross-cultural comparison, measurement invariance of the PVQ-21 was tested. In a first step, confirmatory Factor Analysis (CFA) was conducted separately for each country. Due to the high correlation between the 10 values, the four higher-order dimensions were studied separately. Configural, metric, and scalar invariance models were tested using multigroup CFA. Full metric and partial scalar invariance models held for all higher-order factors. Thereafter, latent means of values were compared across samples. As a result, Chinese students scored highest on the four higher-order dimensions when compared with Russian and German samples, thus the hypotheses were only partly confirmed. Results of this study could reflect the value conflicts emerging from various cultural influences in contemporary China: Young people are confronted with daily negotiation between Confucian tradition and the rapid economic development.