Identification of differentially expressed genes at two key endosperm development stages using two maize inbreds with large and small grain and integration with detected QTL for grain weight.

Maize endosperm accounts for more than 80% of the grain weight. Cell division and grain filling are the two key stages for endosperm development. Previous studies showed that gene expression during differential stages in endosperm development is greatly different. However, information on systematic identification and characterization of the differentially expressed genes between the two stages are limited. In this study, suppression subtractive hybridization (SSH) was used to generate four subtracted cDNA libraries for the two stages using two maize inbreds with large and small grain. Totally, 4,784 differentially expressed sequence tags (ESTs) were sequenced and 902 were non-redundant, which consisted of 344 unique ESTs. Among them 192 had high sequence similarity to the GenBank entries and represent diverse of functional categories, such as metabolism, cell growth/division, transcription, signal transduction, protein destination/storage, protein synthesis and others. The expression patterns of 75.7% SSH-derived cDNAs were confirmed by reverse Northern blot and semi-quantitative reverse transcription polymerase chain reaction, and exhibited the similar results (75.0%). Genes differentially expressed between two key stages for the two inbreds were involved in diverse physiological process pathway, which might be responsible for the formation of grain weight. 43.8% (70 of the 160 unique ESTs) of the identified ESTs were assigned to 39 chromosome bins distributed over all ten maize chromosomes. Eleven ESTs were found to co-localize with previous detected QTLs for grain weight, which might be considered as the candidate genes of grain weight for further study.

[The investigation of the positive rate of intrinsic factor antibody and deficiency rate of vitamin B(12) in normal physical examination population].

Objective: To explore the positive rate of intrinsic factor antibody (IFAb) and level of vitamin B(12) (VitB(12)) in normal physical examination population and the possible relation between IFAb, VitB12 and sex, age, number of RBC, HGB and MCV. Methods: A total of 1 427 people who came to Peking Union Medical Colleague Hospital (PUMCH) for physical examination were enrolled. There were 758 males with average age of (52.5±14.5) years-old and 669 females with average age of (50.3±14.3) year-old. Beckman DxI800 automatic biochemical-immune analyzer and corollary reagents were used to analyze the level of serum IFAb and VitB(12). The results in different sex, age were documented and their correlation with the value of whole blood cell count was tested later on. Results: Among the 1 427 normal subjects, 66 (4.63%) were positive for IFAb. The positive rate for IFAb in the population≥40 years-old was higher than those<40 years-old (5.66% vs 1.48%, χ(2)=7.46, P=0.006). The deficiency rate of VitB(12) in the population<40 years-old, 40-59 years-old and ≥60 years-old was 2.22%, 2.51% and 5.50%, respectively (χ(2)=8.55, P=0.014). There were no difference between people with different sex in the positive rate of IFAb (5.15% for males and 4.04% for females, χ(2)=0.99, P=0.320) or in the deficiency rate of VitB(1)2 (3.83% for males and 2.69% for females, χ(2)=1.44, P=0.230). The results of multiple linear regression showed that HGB level of IFAb positive subjects was 3.05 g/L lower on average than those of IFAb negative, but IFAb had no effect on both RBC and MCV. There was no correlation between VitB(1)2 deficiency and HGB, RBC and MCV. Conclusion: The positive rate of IFAb and deficiency rate of VitB(1)2 increase as age increases. But the presence of VitB(12) deficiency is later than the positive findings of IFAb. IFAb showed some effects on the level of HGB, which may compensate the limitations of VitB(12) detection to some extent. It is necessary to check the IFAb and level of VitB(12) in people with middle or old ages.

[Clinicopathological characteristics of papillary thyroid microcarcinoma and risk factors for central lymph node metastasis].

Objective: To analyze the clinicopathological characteristics of papillary thyroid microcarcinoma (PTMC) and risk factors for central lymph node metastasis(CLNM) in PTMC. Methods: The data of 900 patients with PTMC initially treated in our hospital from January 2004 to December 2015 were retrospectively analyzed. Chi-square test and Logistic regression analysis were performed to determine the risk factors for CLNM. Results: CLNM affected 162 (22.9%) of 707 patients treated with central lymph node dissection. Age, maximum tumor size, multifocality, bilaterality, and extracapsular spread (ECS) were significantly correlated with CLNM (all P<0.01). Age<45 years, maximum tumor size>5 mm, multifocality, bilaterality, and extracapsular spread were independently correlated with CLNM. Conclusion: A prophylactic central lymph node dissection should be considered in PTMC patients with age<45 years, maximum tumor size>5 mm, multifocality, bilaterality, and extracapsular spread.