Predictors of academic career progression among early career physician-scientists via an intensive research training program abroad: a case study.

BACKGROUND: Despite extensive efforts to revitalize the physician-scientist pipeline, attrition has been observed along the physician-scientist developmental pathway. Research exposure during clinical training is considered an important factor favoring the decision to pursue an academic career pathway. METHODS: The authors sought to identify factors associated with academic career progression among junior physician-scientists following the completion of an intensive research training program, using the framework of the Social Cognitive Career Theory (SCCT), to benefit the design of efforts to revitalize the physician-scientist career pipeline. We conducted a retrospective study of 108 physicians who completed a long-term research training program abroad during residency, or within a few years post-residency completion, between 2010 and 2017. With potential predictors of academic career progression prioritized by SCCT, multivariable logistic regression was used to identify predictors of sustained research involvement, high productivity and high research competency after training, respectively. The SCCT was used to illuminate our findings. RESULTS: Co-publications with training supervisors abroad and medical oncology/pediatric oncology as a clinical specialty were positively associated with sustained research involvement and high productivity. Joining the training program after the age of 36 was negatively associated with high research competency. All of the predictors shared a common feature of high correlation with both self-efficacy and environmental elements, the reciprocal interactions of which may affect the career progression of physician-scientists. CONCLUSIONS: Insights gained through this analysis provide policy recommendations for the designing of efforts to revitalize the physician-scientist career pipeline. Priorities should be given to institutional oversight to ensure strengthened self-efficacy at the beginning of one's academic career, by providing long-term research training opportunities to young residents and promoting co-publications with their training supervisors during the training. In order to avoid the negative impact to self-efficacy caused by patient-related burnout or academic isolation, academic medical centers should take measures to guarantee protected research time, and to develop a positive culture encouraging mentoring relationships between junior and experienced physician-scientists in medical departments.

Plasma microRNA profiling in nasopharyngeal carcinoma patients reveals miR-548q and miR-483-5p as potential biomarkers.

MicroRNAs (miRNAs), which play a role in tumorigenesis, may also serve as diagnostic or prognostic biomarkers. However, studies on human miRNA profiles in plasma from nasopharyngeal carcinoma (NPC) patients are in their infancy. Here, we used microarrays to perform systematic profiling of human miRNAs in plasma from NPC patients. We subsequently used real-time quantitative polymerase chain reaction (Q-PCR) to validate miRNAs with aberrant expression that could serve as potential biomarkers. By comparing the plasma miRNA profiles of 31 NPC patients and 19 controls, 39 of 887 human miRNAs were found to be aberrantly expressed. Considering the fold change and P value, miR-548q and miR-483-5p were validated in 132 samples from 82 NPC patients and 50 controls. Moreover, high expression of miR-548q and miR-483-5p was further found in 3 NPC cell lines and clinical biopsy tissues from 54 NPC patients and 22 controls. Our results revealed that miR-548q and miR-483-5p are potential biomarkers of NPC. Combining the receiver operating characteristic (ROC) analyses of these 2 miRNAs, an area under the ROC curve (AUC) of 0.737 with 67.1% sensitivity and 68.0% specificity were obtained, showing the preliminary diagnostic value of plasma miRNAs. Moreover, most NPC patients with a poor outcome exhibited high expression (> median) of miR-548q (70.6%) and miR-483-5p (64.7%) in tissue samples, indicating their prognostic value. The high expression levels of miR-548q and miR-483-5p in plasma, cell lines, and clinical tissues of NPC patients indicate that their roles in NPC should be explored in the future.

Centrifugation: an important pre-analytic procedure that influences plasma microRNA quantification during blood processing.

Circulating microRNAs are robustly present in plasma or serum and have become a research focus as biomarkers for tumor diagnosis and prognosis. Centrifugation is a necessary procedure for obtaining high-quality blood supernatant. Herein, we investigated one-step and two-step centrifugations, two centrifugal methods routinely used in microRNA study, to explore their effects on plasma microRNA quantification. The microRNAs obtained from one-step and two-step centrifugations were quantified by microarray and TaqMan-based real-time quantitative polymerase chain reaction (Q-PCR). Dynamic light scattering was performed to explore the difference underlying the two centrifugal methods. The results from the microarray containing 1,347 microRNAs showed that the signal detection rate was greatly decreased in the plasma sample prepared by two-step centrifugation. More importantly, the microRNAs missing in this plasma sample could be recovered and detected in the precipitate generated from the second centrifugation. Consistent with the results from microarray, a marked decrease of three representative microRNAs in two-step centrifugal plasma was validated by Q-PCR. According to the size distribution of all nanoparticles in plasma, there were fewer nanoparticles with size >1,000 nm in two-step centrifugal plasma. Our experiments directly demonstrated that different centrifugation methods produced distinct quantities of plasma microRNAs. Thus, exosomes or protein complexes containing microRNAs may be involved in large nanoparticle formation and may be precipitated after two-step centrifugation. Our results remind us that sample processing methods should be first considered in conducting research.

Functional polymorphism in the 5'-UTR of CR2 is associated with susceptibility to nasopharyngeal carcinoma.

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is a squamous cell cancer endemic in Southern China and Southeast Asia. It has been shown that inflammatory and immune responses during EBV infection contribute to the development of NPC. The complement receptor 2 (CR2) gene plays central roles during inflammatory and immune responses and, therefore, is a good candidate susceptibility gene for NPC. We performed PCR-based sequencing to identify multiple single-nucleotide polymorphisms (SNPs) within the exon regions of the CR2 gene in a Cantonese population. Two SNPs were screened in 528 NPC patients and 408 normal individuals to perform a case-control study matched according to age, gender and residence. Furthermore, we cloned the entire 5'-UTR and entire CR2 promoter into a luciferase report system and compared the luciferase activities between the different allelic constructs. A SNP in the 5'-UTR of CR2 (24 T/C, rs3813946) showed a significant association (P<0.01) with NPC in the Cantonese population studied. The subjects were categorized into 2 age groups: group 1, age ≤45 years and group 2, age >45 years. In group 1, the allelic frequencies of 24 T/C in the patients were significantly different from those of the controls (P=0.0034). The odds ratio (OR=1.81) also indicated a higher risk of NPC in individuals who carried the minor allele C. All constructs exerted allelic differences on luciferase activities, but only the susceptible allele +24C construct showed increased activity. Our findings implicate CR2 as a susceptibility gene for NPC and suggest that enhanced CR2 expression may be involved in the oncogenesis and development of NPC.

Elevated Epstein-Barr virus seroreactivity among unaffected members of families with nasopharyngeal carcinoma.

Serum antibodies to Epstein-Barr virus (EBV) antigens can be used to predict the risk of nasopharyngeal carcinoma (NPC). To investigate whether EBV seropositivity rates were higher among healthy family members from multiplex and sporadic families with NPC (i.e., families with multiple or single cases) compared to the general population, a study was conducted on 2,665 unaffected individuals from 140 multiplex and 413 sporadic families. The titers of the IgA antibody to the EBV capsid antigen (VCA-IgA) were compared to those of 904 controls from the general population. The VCA-IgA titer was correlated among sibling pairs to a high significance in both family types (P < 0.0001 and P = 0.0005 for the multiplex and the sporadic families, respectively); parent-offspring pairs also showed significant correlation (P < 0.0001 and P = 0.0002, respectively); and spouse pairs were correlated, but at lower significance levels (P = 0.0790 and P = 0.0040, respectively). When compared to the controls, among first-degree relatives in the multiplex families, the age- and gender-adjusted odds ratio (OR) was 2.06 (95% confidence interval 1.56-2.71), 3.55 (2.24-5.64), and 2.25 (1.57-3.23) for siblings, parents, and children, respectively. In the sporadic families, the adjusted OR was 1.55 (1.21-2.00) and 2.08 (1.51-2.86) for siblings and parents, respectively. The adjusted P-value of spouses lost significance in the multiplex families, but remained significant in the sporadic families (P = 0.0146). In conclusion, EBV seropositivity rates were elevated among unaffected family members in both multiplex and sporadic families with NPC.

[Pathogenesis and treatment of non-alcoholic fatty liver disease].

In order to explore the pathogenesis of non-alcoholic fatty liver disease (NAFLD), and to find the best evidence for clinical practice, recent literature about the pathogenesis and treatment of NAFLD was analyzed, and it was found that the generation of reactive oxygen species (ROS) is the most important factor in development of NAFLD. Based on insulin resistance (IR), generation of ROS is a central link in the course of "two hits". Other factors, such as leptin resistance, caspase-3, Fas and its ligand, peripheral natural killer T cells, cyclooxygenase-2, metabolic nuclear receptors, hepatic deposition of iron, ferritin, haptoglobin, retinol binding protein 4, imbalance of intestinal flora, mitochondrial dysfunction and endoplasmic reticulum stress, also contribute to the progress of NAFLD. In the treatment of NAFLD, beside the conventionally used methods such as IR improvement, antioxidation and lipid metabolism improvement, other medicines such as nuclear metabolism ligands or activators, iron-chelating agents and syndrome differentiation treatment in traditional Chinese medicine also have good efficacy.

Noninvasive assessment of liver fibrosis with combined serum aminotransferase/platelet ratio index and hyaluronic acid in patients with chronic hepatitis B.

AIM: To construct a noninvasive assessment model consisting of routine laboratory data to predict significant fibrosis and cirrhosis in patients with chronic hepatitis B (CHB). METHODS: A total of 137 consecutive patients with CHB who underwent percutaneous liver biopsy were retrospectively analyzed. These patients were divided into two groups according to their aminotransferase (ALT) level. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), the likelihood ratio (LR) of aminotransferase/platelet ratio index (APRI) > or = 1.5 or < 1.5 in combination with different hyaluronic acid (HA) cut-off points were calculated for the presence of moderate to severe fibrosis/cirrhosis (fibrosis stages 2 and 4) and no to mild fibrosis/cirrhosis (fibrosis stages 0 and 1). RESULTS: The APRI correlated with fibrosis stage in CHB patients. The APRI > or = 1.5 in combination with a cut-off HA cut-off point > 300 ng/mL could detect moderate to severe fibrosis (stages 2-4) in CHB patients. The PPV was 93.7%, the specificity was 98.9%. The APRI < 1.5 in combination with different HA cut-off points could not detect no to mild fibrosis in CHB patients. CONCLUSION: The APRI > or = 1.5 in combination with a HA cut-off point > 300 ng/mL can detect moderate to severe fibrosis (stages 2-4) in CHB patients.

[Inhibitory effects of human AFP-derived peptide-pulsed dendritic cells on mouse hepatocellular carcinoma].

BACKGROUND & OBJECTIVE: Alpha-fetoprotein (AFP) is a good candidate antigen for the immunotherapy of hepatocellular carcinoma (HCC). How to overcome the immune tolerance induced by autologous antigen is one of key points for inducing effective antitumor immune reaction. This research was to investigate the effect of human AFP-derived peptide-pulsed dendritic cells (hAFP-DCs) on immunity against mouse HCC. METHODS: Bone marrow-originated DCs were prepared routinely. The activity of hAFP-DC-stimulated cytotoxic T lymphocyte (CTL) against Hepa1-6 cells was examined by MTT assay. C57BL/6 mice were inoculated subcutaneously with 7 x 10(6) Hepa1-6 cells to develop hepatoma, and received intratumor injection of hAFP-DCs, DCs and PBS, respectively, twice a week. Tumor volume was evaluated and the survival of mice after inoculation was observed. RESULTS: We successfully prepared DCs from bone marrow of mice. The cytotoxic activity of CTLs stimulated by hAFP-DCs and DCs showed stronger tendency than that of control, but without significance. The mean tumor volume at 31 days after inoculation with Hepa1-6 cells was (195.04+/-155.22) mm3 in hAFP-DCs group, (360.65+/-209.02) mm3 in DCs group and (756.19+/-503.24) mm3 in PBS group. The differences among these three groups were significant (P < 0.001). The survival rate of mice at 40 days after inoculation was 100% in hAFP-DCs group, 90% in DCs group and 50% in PBS group (P=0.008). CONCLUSION: Human AFP-derived peptide-pulsed DCs can efficiently enhance immunity against HCC in mice.

[Functions of V-val subtype of Epstein-Barr nuclear antigen 1].

BACKGROUND & OBJECTIVE: Epstein-Barr viral nuclear antigen 1 (EBNA1) plays a crucial role in the latency of Epstein-Barr virus (EBV). A close relation of V-val subtype of EBNA1 with nasopharyngeal carcinoma (NPC) was suggested by its preference to infect NPC cells. This study was to investigate the functional difference between prototype and V-val EBNA1 in epithelial cell line HEK293. METHODS: The coding sequences of prototype and V-val EBNA1 were amplified by polymerase chain reaction and cloned into pGFP vector, then transfected into HEK293 cells respectively. The biological consequences of EBNA1 gene expression were examined. The transcriptional activation ability was compared between prototype and V-val subtype of EBNA1 using luciferase reporter system containing family of repeats (FR) sequence of EBV. RESULTS: Prototype and V-val EBNA1 showed no effect on cell proliferation, while the cloning efficiency of prototype EBNA1-expressing cells was obviously lower than that of V-val EBNA1-expressing cells. No tumor formed in nude mice after injection of prototype or V-val EBNA1-trasfected HEK293 cells. However, the luciferase activity was significantly higher in V-val EBNA1-expressing HEK293 cells than in prototype EBNA1-expressing HEK293 cells in transient transfection assay. CONCLUSION: Prototype and V-val EBNA1 have no direct transforming activity on cells, whereas the transactivation activity of V-val EBNA1 in FR-containing plasmid is significantly higher than that of prototype EBNA1.

[Expression and implication of base excision repair genes in human nasopharyngeal carcinoma and non-tumor nasopharyngeal tissues].

BACKGROUND & OBJECTIVE: Base excision repair (BER) genes play important roles in maintaining genomic stability and their abnormal expression are associated with several cancers. This study was to investigate the expression of 7 important BER genes (hOGG1, ADPRT, APE1, MBD4, POLB, XRCC1 and LIG3) in nasopharyngeal carcinoma (NPC) and non-tumor nasopharyngeal tissues, and evaluate their clinical significance. METHODS: The expression of hOGG1, ADPRT, APE1, MBD4, POLB, XRCC1 and LIG3 in 24 specimens of NPC and 24 specimens of non-tumor nasopharyngeal tissues was detected by reverse transcription-polymerase chain reaction (RT-PCR). The differential expression of hOGG1 and ADPRT was further detected by immunohistochemistry in 99 specimens of NPC and 28 specimens of non-tumor nasopharyngeal tissues. RESULTS: hOGG1, ADPRT, APE1, MBD4, POLB, XRCC1 and LIG3 were expressed in both NPC and non-tumor nasopharyngeal tissues. Among them, the mRNA levels of hOGG1 and ADPRT were significantly lower in NPC than in non-tumor nasopharyngeal tissues (P<0.001). The protein levels of hOGG1 and ADPRT in NPC were also reduced. The high expression rates of hOGG1 were 50.5% in NPC and and 92.8% in non-tumor nasopharyngeal tissues (P<0.001), and those of ADPRT were 53.5% and 96.4%, respectively (P<0.001). However, the expression levels of hOGG1 and ADPRT had no correlations to the clinical stage and prognosis of NPC. CONCLUSION: The decreased expression of hOGG1 and ADPRT might be closely related to the development of nasopharyngeal carcinoma.

Genetic polymorphisms of TLR3 are associated with Nasopharyngeal carcinoma risk in Cantonese population.

BACKGROUND: Nasopharyngeal carcinoma is endemic in Southern China, displays a strong relationship with genetic susceptibility and associates with Epstein-Barr virus infection. Toll-like receptor 3 (TLR3) plays an important role in the antivirus response. Therefore, we examined the association between TLR3 gene polymorphisms and NPC susceptibility. METHODS: We performed a case-control study of 434 NPC cases and 512 healthy controls matched on age, sex and residence. Both cases and controls are of Cantonese origin from Southern China. Genetic variants in TLR3 were determined by polymerase chain reaction (PCR)-based DNA direct sequencing and four SNPs were genotyped in all samples. RESULTS: Our results showed that allele C for SNP 829A/C increased NPC risk significantly ((p = 0.0068, OR = 1.49, 95%CI:1.10-2.00). When adjusted for age, gender and VCA-IgA antibody titers, the NPC risk was reduced significantly among individuals who carried the haplotype "ATCT" compared to those who carried the most common haplotype "ACCT" (p = 0.0054, OR = 0.028; 95% CI (0.002-0.341). CONCLUSION: The TLR3 polymorphisms may be relevant to NPC susceptibility in the Cantonese population, although the reduction in NPC risk is modest and the biological mechanism of the observed association merits further investigation.

Sequence variants in toll-like receptor 10 are associated with nasopharyngeal carcinoma risk.

Nasopharyngeal carcinoma (NPC) is a common malignancy in southern China and Southeast Asia. Genetic susceptibility is a major factor in determining the individual risk of NPC in these areas. To test the association between NPC and variants in Toll-like receptor 10 (TLR10), we conducted a hospital-based case-control study in a Cantonese-speaking population in Guangdong province. Seven single nucleotide polymorphisms in TLR10, selected with a tagging algorithm, were genotyped. When assessing each unique haplotype compared with the most common haplotype, "GAGTGAA," with the expectation-maximization algorithm in Haplo.stats, the risk of developing NPC was significantly elevated among men who carried the haplotype "GCGTGGC" (P = 0.005). After adjusting for age, gender, and VCA-IgA antibody titers, this association was more significant (P = 0.0007). To further assess the overall differences of haplotype frequency profiles between cases and healthy controls, the global score test, considering all haplotypes and adjusting for age, gender, and VCA-IgA antibody titers, gave a haplo score of 27.52 with P = 0.002. The haplotype specific odds ratio was 2.66 (confidence interval, 1.34-3.82) for GCGTGGC. We concluded that in this Cantonese population-based study, haplotype GCGTGGC with frequency of 11.4% in TLR10 was found to be associated with NPC and this association was statistically significant after adjusting for age, gender, and VCA-IgA antibody titers. It is possible that this is not a causal haplotype for NPC; rather, it is in strong linkage disequilibrium with a causal single nucleotide polymorphism in close proximity.

[Study on clonal expression of T cells bearing dominant TCR Vß in non-small-cell lung cancers].

BACKGROUND: To investigate the distribution of TCR Vß subfamily T clonal cells in peripheral blood lymphocytes (PBL), tumor infiltrating lymphocytes (TIL) and lymphocytes in non-cancerous lung tissues of patients with non-small-cell lung cancer (NSCLC) and to see the inclination of the T cell antigen receptor (TCR) Vß subfamilies' expression. METHODS: Complimentarily determining region 3 (CDR3) of TCR 24 variable region genes was analyzed in PBL, TIL and lymphocytes in non cancerous lung tissues from 24 NSCLC cases with reverse transcriptase-polymerase chain reaction (RT-PCR) and gene scan techniques to identify the distribution and clonality of TCR Vß subfamily T cells. RESULTS: Only a portion of Vß T cells were found in patients with NSCLC, whereas 24 TCR Vß subfamily T cells were detected in 10 healthy controls. Vß5 subfamily was expressed mostly in TIL and the frequency of Vß5 in TIL (6/18, 33.3%) was much higher than that of PBL (1/24, 4.2%) and T cells infiltrating non-cancerous lung tissues (0/12) (P < 0.05). Oligoc lonal T cells were found in 2 cases with Vß5 subfamily and polyclonal T cells in 4 cases. CONCLUSIONS: There are dominant and clonal TCR Vß subfamilies expressed in TIL of NSCLC patients, which may be the tumor associated antigens (TAA) specific.

[The relationship between microvessel density and structure in cancer tissues and prognosis in patients with non-small cell lung cancer].

BACKGROUND: To explore the correlation of microvessel density (MVD) and microvessel structure (MVS) features with the patients' prognosis in non-small cell lung cancer (NSCLC). METHODS: Anti-Von Willebrand factor antibody was used to stain microvessel endothelia by means of LsAB immunohistochemical technique, then the microvessel count and structure features were observed microscopically in 49 primary NSCLC tissues. MVS pattern A had scattered microvessels with relatively integral or thick wall and with relatively regular morphology and MVS pattern B had plexiform or network like microvessels with unintegral or thin wall and with irregular morphology. RESULTS: MVD in primary NSCLC tissues was closely correlated with pTNM stage or lymph node involvement, P=0.043 and P=0.038, respectively. MVS in primary NSCLC tissues was closely correlated with the size of primary carcinoma, P=0.002. The survival of patients (23.2± 18.4 months) with MVD > 52/200× was significantly shorter than that of patients (35.9±20.9 months) with MVD < 52/200× in primary NSCLC tisssues, P=0.01. The survival of patients with MVS pattern A (39.4±17.2 months) was significantly longer than that of patients with MVS pattern B (23.5±20.3 months) in primary NSCLC tisssues, P=0.008. The survival of patients with MVD < 52/200× and MVS pattern A (42.9±19.3 months) was significantly longer than that of patients with MVD > 52/200× and MVS pattern B (15.7±16.8 months) in primary NSCLC tissues, P=0.002. CONCLUSIONS: MVD and MVS are closely associated with prognosis of NSCLC patients and might be served as parameters estimating patients' prognosis and planning assistant therapy after operation.