Transmission Potential of Asymptomatic and Paucisymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infections: A 3-Family Cluster Study in China.

Data concerning the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in asymptomatic and paucisymptomatic patients are lacking. We report a 3-family cluster of infections involving asymptomatic and paucisymptomatic transmission. Eight of 15 (53%) members from 3 families were confirmed with SARS-CoV-2 infection. Of 8 patients, 3 were asymptomatic and 1 was paucisymptomatic. An asymptomatic mother transmitted the virus to her son, and a paucisymptomatic father transmitted the virus to his 3-month-old daughter. SARS-CoV-2 was detected in the environment of 1 household. The complete genomes of SARS-CoV-2 from the patients were > 99.9% identical and were clustered with other SARS-CoV-2 sequences reported from China and other countries.

Genetic polymorphisms of DNA repair pathways influence the response to chemotherapy and overall survival of gastric cancer.

We aimed to evaluate the clinical response to platinum-based chemotherapy and treatment outcome of gastric cancer patients in the present of ERCC1, ERCC2, NBN, RAD51, and XRCC3 gene polymorphisms. A number of 415 patients of gastric cancer that received platinum-based chemotherapy were enrolled in the present study. The presence of ERCC1 rs11615 and rs2298881, ERCC2 rs1799793 and rs13181, NBN rs1805794, rs709816, and RAD51 rs1801321 and XRCC3 rs1799794 were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Conditional regression analysis identified that CC genotype of ERCC1 rs11615 and AA genotype of ERCC2 rs1799793 was associated with a better response to chemotherapy in gastric cancer patients, and the odds ratio (ORs)(95% confidence interval (CI)) were 2.70(1.33-5.70) and 3.12(1.52-6.84), respectively. By the Cox analysis, the CC genotype of ERCC1 rs11615, AA genotype of ERCC2 rs1799793, and CC genotype of NBN rs1805794 were significantly associated with a longer overall survival (OS) of gastric cancer. In conclusion, our results suggest that ERCC1 rs11615, ERCC2 rs1799793, and NBN rs1805794 polymorphisms in the DNA repair pathways may influence the response to chemotherapy and OS of gastric cancer.

Lasting antibody and T cell responses to SARS-CoV-2 in COVID-19 patients three months after infection.

The dynamics, duration, and nature of immunity produced during SARS-CoV-2 infection are still unclear. Here, we longitudinally measured virus-neutralising antibody, specific antibodies against the spike (S) protein, receptor-binding domain (RBD), and the nucleoprotein (N) of SARS-CoV-2, as well as T cell responses, in 25 SARS-CoV-2-infected patients up to 121 days post-symptom onset (PSO). All patients seroconvert for IgG against N, S, or RBD, as well as IgM against RBD, and produce neutralising antibodies (NAb) by 14 days PSO, with the peak levels attained by 15-30 days PSO. Anti-SARS-CoV-2 IgG and NAb remain detectable and relatively stable 3-4 months PSO, whereas IgM antibody rapidly decay. Approximately 65% of patients have detectable SARS-CoV-2-specific CD4+ or CD8+ T cell responses 3-4 months PSO. Our results thus provide critical evidence that IgG, NAb, and T cell responses persist in the majority of patients for at least 3-4 months after infection.

Diet folate, DNA methylation and polymorphisms in methylenetetrahydrofolate reductase in association with the susceptibility to gastric cancer.

Methylenetetrahydrofolate reductase (MTHFR) has been reported to be associated with DNA methylation, an epigenetic feature frequently found in gastric cancer. We conducted a case-control study to explore the association of MTHFR C677T polymorphisms with gastric cancer risk and its relation with the DNA methylation of COX-2, MGMT, and hMLH1 genes. Genotyping of P16, MGMT and HMLH1 was determined by methylation-specific PCR after sodium bisulfate modification of DNA, and genotyping of MTHFR C677T was conducted by TaqMan assays using the ABI Prism 7911HT Sequence Detection System. Folate intake was calculated with the aid of a questionnaire. Compared with the MTHFR 677CC genotype, the TT genotype was significantly associated with 2.08 fold risk of gastric cancer when adjusting for potential risk factors. Individuals who had an intake of folate above 310 µg/day showed protective effects against gastric cancer risk. The effect of MTHFR C677T polymorphisms on the risk of gastric cancer was modified by folate intake and methylation status of MGMT (P for interaction <0.05).

Smoking initiation and schizophrenia: a replication study in a Chinese Han population.

Schizophrenia is associated with a greater probability of ever smoking daily and with higher rates of initiation of daily smoking after age 20 in Caucasian populations. The aims of the current study were to replicate that schizophrenia is associated with smoking and higher risk of initiating daily smoking before schizophrenia starts among a large sample of male Chinese patients. A survival analysis of onset age for daily smoking compared 776 DSM-IV male inpatients with schizophrenia to 560 male controls. The results showed that the cumulative hazard curves for age of smoking initiation in schizophrenia and controls were significantly different (p<0.001), even after controlling for education (p<0.001). After excluding the patients who started smoking within 5 years before schizophrenia started, the cumulative hazard curve for schizophrenia was significantly different from ever-smoked controls (p<0.001), even after adjusting for education (p<0.001). These findings suggest that schizophrenic patients have a higher risk of starting daily smoking suggesting that vulnerability to schizophrenia may be associated with a higher risk of becoming a daily smoker.

The study of BDNF Val66Met polymorphism in Chinese schizophrenic patients.

Accumulating evidence showed that brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of schizophrenia. Recent studies have reported that the Val66Met polymorphism of the BDNF gene may be associated with susceptibility for schizophrenia and age of onset of this disease, with mix results. In the present study, the BDNF Val66Met gene polymorphism was examined in 387 inpatients (259 men and 128 women) meeting the DSM-IV criteria for schizophrenia and unrelated 365 healthy controls (255 men and 110 women). The schizophrenia symptomatology was assessed by the Positive and Negative Syndrome Scale (PANSS). Age of onset was defined as the age at which the psychotic symptoms first appeared. Our results showed that genotype frequency distributions and allelic frequencies did not differ between patients and controls. No interaction was found between sex and genotypes. Analysis of covariance (ANCOVA) showed a significance of the BDNF Val66Met genotypes on the age of onset (F=3.76, p<0.02), after adjusting sex, age and duration of illness. Furthermore, ANCOVA showed that the significance of the BDNFVal66Met genotypes on age of onset was increased comparing the Val66Met heterozygotes with the combination of Val66Val and Met66Met homozygotes (F=5.85, p<0.01). Our results suggest that the BDNF Val66Met polymorphism may not contribute directly to the susceptibility to schizophrenia, but to the onset of the disease. Furthermore, our results show the heterozygous effect of the BDNF Val66Met gene on the clinical variability of schizophrenia phenotype.