Modeling Methods and Influencing Factors for Age Estimation Based on DNA Methylation.

Age estimation based on tissues or body fluids is an important task in forensic science. The changes of DNA methylation status with age have certain rules, which can be used to estimate the age of the individuals. Therefore, it is of great significance to discover specific DNA methylation sites and develop new age estimation models. At present, statistical models for age estimation have been developed based on the rule that DNA methylation status changes with age. The commonly used models include multiple linear regression model, multiple quantile regression model, support vector machine model, artificial neural network model, random forest model, etc. In addition, there are many factors that affect the level of DNA methylation, such as the tissue specificity of methylation. This paper reviews these modeling methods and influencing factors for age estimation based on DNA methylation, with a view to provide reference for the establishment of age estimation models.

[Method of Identifying Male Lineages Based on Main Haplotype and Analysis of the Distribution of Y-STR Haplotype Mismatch Based on the Bayesian Theory].

OBJECTIVE: To establish a classification method to identify different male lineages in a large population, to study the distribution patterns of Y-STR loci mismatches among Han Chinese male lineage members and to explore the mismatch probability distribution among the members with different meiosis intervals in the family. METHODS: Peripheral blood samples of 269 male individuals from 12 lineages in Han Chinese population and 45 unrelated male individuals were collected. Then, Yfiler Plus TM and ZGWZ FSY or Yfiler Platinum amplification kits were used, obtaining 314 Y-STR haplotypes. The Y-STR haplotype with 3 or more repetitions were selected as the main haplotype, in which the largest number was selected as the first data center. According to the standard of Y-STR genotype, those with mismatches within five loci and six steps were clustered and merged. Then, the main haplotype of the largest number in the remaining data was taken as the second data center, and cluster analysis is carried out in turn until there is no main haplotype remained. Pair comparison was conducted between lineage members and unrelated individuals, and the mismatch distribution among lineage members and unrelated individuals was calculated respectively. The average mismatch rate of each locus was subsequently calculated, as well as the mismatch probability distribution among members with different meiosis intervals within the lineage. RESULTS: 269 out of the 314 individuals were divided into 12 groups by cluster analysis method, accomplishing 100% accuracy between the cluster groups thus identified and the 12 known lineages. The remaining 45 unrelated individuals were scattered. The mismatch loci was within 0-7 loci and 0-7 steps among lineage members and the mismatch between unrelated individuals was at least 11 loci and 15 steps. The mismatch loci with the largest number of one-step and two-step mismatch were different in each lineage and had features that were specific to each lineage. The minimum mutation count and average mismatch rate of each locus were significantly correlated with the mutation rate. Two individuals with no mismatch had a 19.7% probability of 1 meiosis interval and a 71.2% probability of less than 6 meiosis interval. Two individuals with 3 loci mismatches had a 65.2% probability of more than 10 meiosis intervals. CONCLUSION: The cluster analysis method based on main haplotypes provided in this paper can quickly and effectively differentiate large male lineage samples. The clustering method and the mismatch probability distribution of different meiosis intervals obtained thus can provide new ideas for research and screening instruments, and important reference for lineage investigation, data analysis and practical application of Y-STR database in the future.

Computer-aided superimposition of the frontal sinus via 3D reconstruction for comparative forensic identification.

The anatomical uniqueness of the frontal sinus morphology has been widely used for comparative forensic identification using various techniques, mostly including 2D X-rays or one fixed slice of an axial computed tomography (CT) scan image. However, computer-aided 3D automatic graphical comparison techniques can provide accurate comparisons between two 3D models that allow users to comply with even the strictest deviation standards, avoiding error-prone identification of frontal sinuses with similar morphologies. The study proposes the use of a computer-aided comparative paradigm based on the 3D-3D frontal sinus model superimposition process and further assesses the anatomical uniqueness of frontal sinuses using a large Chinese Han sample. Three hundred thirty-six patients older than 20 years with two multi-slice CT scans were collected. Frontal sinus 3D models were semi-automatically segmented through Dolphin Imaging software. Automatic pairwise comparisons of 336 matched pairs from the same person and 340 mismatched pairs from different individuals with an analysis of average root mean square (RMS) point-to-point distance were performed using Geomagic Studio Qualify software. RMS ranged between 0.005 and 1.032 (mean RMS 0.390 ± 0.25 mm) in the group of matches and between 1.107 and 19.363 (mean RMS 4.49 ± 2.69 mm) in the group of mismatches. On average, the RMS value was over ten-fold greater in mismatches than in matches. Statistically significant differences in RMS between the group of matches and mismatches were assessed using the Mann-Whitney U test (p < 0.05). This study supports the value of the frontal sinus with a 3D computer-aided superimposition method for human identification with large samples when DNA, fingerprints, and dental materials are not accessible.

Morphological analysis of three-dimensionally reconstructed frontal sinuses from Chinese Han population using computed tomography.

The uniqueness and reliability of frontal sinuses for personal identification have gained wide recognition in forensics. However, few studies have assessed the usefulness of a three-dimensional (3D) model of the frontal sinus for human identification. This study aimed to develop standardized techniques to classify the frontal sinus according to its 3D morphological metrics and discover the usefulness of the 3D frontal sinus model in identification of Chinese Han population. One hundred and ninety-six computed tomography (CT) scans of patients older than 20 years (84 males and 112 females) were collected. A 3D frontal sinus digital model was segmented using Dolphin Imaging software. The following morphological metrics of the 3D frontal sinus were used to develop the coding system: bilateral or unilateral, spatial relationships of the two sides, number of septations, superior volume side, the shape of the 3D model of each side, shape of the medial surface and frontal ostium on each side, number of accessory septations on each side, number of supra-orbital cells of the medial surface and lateral surface on each side, and number of the arcades on each side. The new coding system accurately identified all of our research individuals. This study discovered a number of individual variations in the 3D frontal sinus morphology patterns. A coding system, which is based on these morphological patterns, exposes the morphological variants of frontal sinuses and presents the usefulness of 3D frontal sinus model for human identification.

Circular Ribonucleic Acid Expression Profile in Mouse Cortex after Traumatic Brain Injury.

Traumatic brain injury (TBI) causes high rates of worldwide death and morbidity because of the complex secondary injury cascade. Circular ribonucleic acid (RNA) (circRNA), a type of RNA that forms a covalently closed continuous loop, may be involved in the regulation of secondary injury because it is expressed widely in the brain and contributes to a large class of post-transcriptional regulators. Deep RNA sequencing (RNA-seq) and bioinformatic analysis were performed to investigate the expression profile and function of circRNAs in the mouse cortex after controlled cortical impact (CCI). A total of 19,794 circRNAs were identified, and 1315 were annotated in circBase. There were 191 filtered differentially expressed circRNAs (98 for up-regulated and 93 for down-regulated). The gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that inflammation, cell death, and repair of damage were the main biological processes and molecular mechanisms related to altered circRNAs. The pathway-circRNA interaction network revealed three core circRNAs and five corepathways related to TBI. The circRNA-messenger RNA (mRNA) interaction network and competitive endogenous RNA (ceRNA) analysis suggested potential microRNA (miRNA) sponges and target mRNAs. In addition to five optimal circRNA-miRNA-mRNA pairs were analyzed, circRNA_16895-miRNA myosin-10 (Myo 10) was predicted to regulate fragment crystallizable gamma receptors (FcγR)-mediated phagocytosis pathway. Four circRNAs were selected for quantitative real-time polymerase chain reaction analysis to validate the sequencing data. Our results provide promising functions of circRNAs aberrantly expressed in TBI to explore molecular mechanisms and potential therapeutic targets for its therapy.

Predicting hepatocellular carcinoma development for cirrhosis patients via methylation detection of heparocarcinogenesis-related genes.

Background: Most hepatocellular carcinoma (HCC) patients have undergone a progression from chronic hepatitis, then liver cirrhosis (LC), and finally to carcinoma. The objective of this study was to elucidate risk factors to predict HCC development for cirrhosis patients. Methods: Multiple methylated specific PCR (MSP) was applied to determine methylation status of heparocarcinogenesis-related genes in 396 tissue and plasma specimens and multivariate cox model was used to analyze the relationship between risk variables and HCC development among cirrhosis patients, followed up in a median period of 30 months. Results: Among 105 LC cases, HCC incidence rate at 30 months was 30.48% (32/105), which were statistically associated with patients' age and aberrant methylation of p16, SFRP, and LINE1 (p<0.05). Receiver operating characteristic (ROC) curve showed the overall predictive accuracy reached the highest (90.7%) if the four risk variables were concurrent to predict HCC development. Moreover, along with the growth of age from 0-40, 40-55, to 55-70 years or the increased number of aberrantly-methylated gene from 0-1 to 2-3, the HCC incidence rate of cirrhosis patients rised from 10.00%, 12.28% to 82.14% and 17.44% to 89.47%, separately. Thus, based on combined analysis with diverse age and number of aberrantly-methylated gene, 105 cases were divided into five groups and computed their respective HCC incidecne rate to categorize them into different risk groups. Of note, A significant lifting of HCC incidence rate in the high-risk group (40-55 years coupled with 2-3 aberrantly-methylated genes, 55-70 years coupled with 0-1 aberrantly-methylated gene, 55-70 years coupled with 2-3 aberrantly-methylated genes; n=33) was observed compared with the low-risk group (0-40 years coupled with 0-1 aberrantly-methylated gene, 40-55 years coupled with 0-1 aberrantly-methylated gene; (n=72) (p<0.01). Conclusions: Ultimately, high-risk cirrhosis patients with 55-over years or 2-3 aberrantly-methylated genes should be paid more attention to be regularly screened with HCC development.

Application of multiplex methylated-specific PCR with capillary electrophoresis to explore prognostic value of TSGs hypermethylation for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is a malignant tumor that severely threatens human health. To date, early detection for HCC patients is particularly significant due to their poor survival rates even after liver resection. METHODS: Therefore, an efficient and sensitive detection method for monitoring liver cancer, multiplex methylation-specific PCR (MSP) coupled with capillary electrophoresis, is developed. RESULTS: Simulations demonstrated that the methylation status of RASSF1A, p16, SFRP1, and ELF could be detected even when DNA equaled or exceeded 12.5 ng simultaneously. Also, its accuracy for methylation detection outweighed polyacrylamide gel electrophoresis (87.5%) and agarose electrophoresis (84.3%), reaching 92.1%. Subsequently, we implemented multiplex MSP with capillary electrophoresis to investigate methylation status of the four tumor suppressor genes in tissue specimens and explore the prognostic value for HCC patients. As the data suggested, multivariate cox regression analysis revealed that the recurrence-free survival of 46 patients was greatly associated with portal vein tumor thrombus (PVTT) and p16 methylation and receiver operating characteristic (ROC) curves demonstrated that the predictive range of portal vein tumor thrombus (PVTT) combined with p16 hypermethylation was more sensitive than that of either PVTT or p16 hypermethylation alone with regard to disease recurrence in patients with HCC, which could be testified as a valuable biomarker in Clinical application. CONCLUSION: Multiplex MSP coupled with capillary electrophoresis has an excellent prospect of clinical application for monitoring early liver cancer and screening valuable biomarkers for prognosis of HCC patients.

Associations between PBDEs exposure from house dust and human semen quality at an e-waste areas in South China-A pilot study.

Previous studies have confirmed that house dust is one of the main sources of polybrominated diphenyl ethers (PBDEs) exposure, and also indicated that PBDEs might affect human semen quality. The aim of this study was to explore the association between PBDEs concentration in house dust and the semen quality of male resident. Results showed that the semen qualities of the residents living around the e-waste dismantling workshops for a long time (3-17years) at the e-waste areas in South China significantly decreased, and the DNA damage of sperms were aggravated. The adjusted correlation analysed by multiple linear regression model showed that the sperm concentration and count both had negative correlation with BDE47 level in semen (ß = -0.295, 95%CI: -0.553∼-0.036; ß = -0.400, 95%CI: -0.708∼-0.092, respectively). In addition, the sperm progressive motility [(A+B)%] and sperm viability both had negative correlation with BDE100 level in dust (ß = -0.360, 95%CI: -0.680∼-0.040; ß = -0.114, 95% CI: -0.203∼-0.025, respectively). And there were significant linear positive correlation between PBDE congener (e.g. BDE28, 47, 153) concentrations in dust and in paired semen samples (rs = 0.367-0.547, p < 0.05). This study suggested that exposure to PBDEs from house dust might have adverse effects on human semen quality. But the results need to be confirmed in further studies with a large-scale sampling, and find out more direct and convincing evidence.

No association between single nucleotide polymorphisms in pre-mirnas and the risk of gastric cancer in Chinese population.

OBJECTIVE(S): Accumulating evidence has demonstrated that miRNAs contribute to various genetic and epigenetic modifications in the pathogenesis of gastric cancer (GC). Recent studies focused on the four single nucleotide polymorphisms (SNPs) of pre-miRNAs including rs11614913, rs3746444, rs2910164, and rs2292832. It was suggested that these four SNPs were significantly associated with the risk of GC and were described as candidate susceptibility factors. However, the previous results show conflicting findings. The aim of this study was to investigate whether these four SNPs are associated with GC in Chinese Han population. MATERIALS AND METHODS: Genotype frequencies of these four SNPs of pre-miRNAs in 220 GC patients and 530 control subjects were performed using a PCR-RFLP assay. RESULTS: No significant differences in genotype and allelic distribution were found in these four SNPs between GC and control subjects in the Chinese Han population. However, we found that the allelic frequency distributions of control subjects in these four SNPs were significantly different from those of the Japanese and the Koreans (All the P<0.05). CONCLUSION: The four SNPs did not show any significant correlation with the development of GC in the Chinese Han population, based on the current study.

Engrailed-2 is down-regulated but also ectopically expressed in clear cell renal cell carcinoma.

Engrailed-2 (EN2), a member of the homeobox family of genes, encodes a homeodomain-containing transcription factor that is thought to be a potential oncogene in a number of cancers. Because the role of EN2 in clear cell renal cell carcinoma (CCRCC) has not been determined, we investigated its expression in CCRCC tissues and cell lines. Using immunohistochemical (IHC) staining, we found that EN2 protein was expressed in normal renal cells and tubules, but was frequently down-regulated in tissues from patients with CCRCC and in CCRCC cell lines. In addition, we found that EN2, which functions in the nucleus, was completely localized to the cytoplasm of CCRCC cells as detected by IHC and immunofluorescence staining. Furthermore, expression of EN2 protein was negatively correlated with increasing histological grade of CCRCC tumors (P = 0.003). The exact role of EN2 expression in renal carcinoma carcinogenesis requires further investigation.

Quantitative histological analysis and ultrastructure of the aging human testis.

PURPOSE: To quantitatively assess the histological and ultrastructural changes resulting from aging in the human testis. METHODS: Age-related histological and ultrastructural changes were evaluated using light microscopy, transmission electron microscopy (TEM) and immunohistochemistry on 41 testicular samples obtained from elderly men and, respectively, assigned to group A (n = 20), 54-69 years old or group B (n = 21), 70-89 years old. Testicular samples derived from 17 young men were used for control. RESULTS: The numbers of Sertoli cells in the aged groups were significantly lower than that in the controls (p < 0.05). With the exception of the Sertoli cell ratios (germ cells/Sertoli cells) of spermatogonia and primary spermatocytes, results showed lower levels of the Sertoli cell ratios of round spermatids and elongated spermatids in the elderly men compared with the young men (p < 0.05). A similar degenerative pattern of the organelles was shown in germ cells and Sertoli cells in the aging testes under TEM. Immunohistochemistry revealed an increased apoptosis index (AI) (0.81 ± 0.13) accompanied by a decreased proliferation index (PI) (30.08 ± 4.86) in the group B (p < 0.05), while both AI and PI were similar between the group A (0.54 ± 0.06; 36.38 ± 7.38) and the controls (0.50 ± 0.15; 40.55 ± 7.92) (p > 0.05). CONCLUSIONS: Aging has negative influence on testicular morphology and spermatogenesis, and the failure of spermatogenic cell development is evident from the spermatid level.

Genetic polymorphisms in Matrix Metalloproteinases -1 and -7 and susceptibility to gastric cancer: an association study and meta-analysis.

Matrix Metalloproteinases (MMPs) play an important role in gastric cancer (GC). Accumulated evidence suggests that functional MMP-1 and MMP-7 gene polymorphisms are associated with several tumors. The aim of this study was to investigate two single nucleotide polymorphisms, MMP-1 -1607 1G/2G and MMP-7 -181 A/G, and their potential relationship with GC. We examined 246 GC patients and 252 age-and sex-matched controls from Sichuan province in China. Genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism strategy and DNA sequencing. We also performed a meta-analysis of relevant studies, involving 1084 cases and 1721 controls, to place our findings in a broader context. No significant relationship was observed between the MMP-1 -1607 1G/2G alleles and genotypes and the risk of GC. There were significant differences in the genotypes and allele distributions of the -181 A/G polymorphism of the MMP-7 gene between cases and controls. The -181 A allele carriers had a significantly increased risk of GC compared with -181 G allele carriers (OR=3.051, 95% CI, 1.475-6.310, P=0.002), and the AA genotype of -181 A/G was associated with an increased risk of GC compared with the AG genotype (OR=3.189, 95% CI, 1.523-6.676, P=0.001). A meta-analysis of six studies also showed a significant risk of GC associated with MMP-7 polymorphism.

Expression of basigin in the early phase of acute myocardial ischemia in rats.

Basigin may be involved in cardiovascular disease. In our previous study, suppression subtractive hybridization results indicated that basigin may be associated with the early phase of acute myocardial ischemia (AMI) within 1 h. However, little is known regarding the expression of basigin in the early phase of AMI. The aim of the present study was to evaluate the temporal and spatial expression patterns of basigin mRNA and protein levels in AMI in rats. We constructed an AMI model in rats that received left anterior descending coronary artery ligation for 0, 15, 30, 60, 120 or 240 min. Real­time quantitative PCR and in situ hybridization (ISH) were conducted to reveal the basigin mRNA levels in the early ischemic myocardium (EIM) and non­ischemic myocardium (NIM). The expression levels of basigin protein were detected using western blot analysis and immunohistochemistry. The expression levels of basigin mRNA and protein significantly changed in the EIM as early as 30 min from ischemia, and the changes continued to be present throughout the ischemic period (P<0.05). The expression levels of basigin mRNA were significantly reduced, whilst those of the protein underwent a significant ~2-fold increase in the EIM. However, there were no significant differences in the basigin mRNA or protein expression levels from 0­240 min in the NIM (P>0.05). We failed to detect a signal for basigin mRNA in the myocardium by ISH. Our findings indicated that basigin may be involved in acute myocardial ischemia following continual ischemia for >30 min.

A genetic variant in the promoter region of miR-34b/c is associated with a reduced risk of colorectal cancer.

The miR-34 family members, described as potential tumor suppressors, were downregulated in colorectal cancer (CRC). Loss of miR-34 impairs TP53-mediated cell death, while overexpression of miR-34 induces apoptosis. A potentially functional polymorphism (i.e., rs4938723T/C) in the promoter region of pri-miR-34b/c was predicted to influence the GATA-X binding sites. We aimed to investigate the association between miR-34b/c rs4938723 and TP53 Arg72Pro polymorphisms and the risk of CRC. We genotyped the two polymorphisms in 347 CRC patients and 488 healthy controls using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing assay. We found that the CC genotype and C allele of the miR-34b/c rs4938723 were associated with a significantly decreased risk of CRC compared with the TT genotype and T allele (CC vs. TT: adjusted OR=0.56; 95% CI, 0.34-0.91; C vs. T: adjusted OR=0.78; 95% CI, 0.64-0.97). In combined analysis, a borderline significance was also observed in subjects carrying the rs4938723 CT/CC and TP53 GG genotypes (adjusted OR=0.66; 95% CI, 0.43-0.99). These findings indicate that the rs4938723 in the promoter region of pri-miR-34b/c was a protective factor for the development of CRC. As the significance is marginal, further replication studies are warranted to confirm these results.

[Expression of SSB following early myocardial ischemia in rats].

OBJECTIVE: To investigate the expression of Sjögren's syndrome antigen B (SSB) gene and SSB protein in the early ischemic myocardium in rats. METHODS: Adult healthy Sprague-Dawley rats were randomly divided into groups of operation [myocardial ischemia (MI) and non-ischemia (NI)], non-operation (NO) and sham-operation (SO) (n = 6 for MI and NI; n = 4 for NO and SO). According to time of ischemia, it was then divided into groups of 0 min, 15 min, 30 min, 60 min, 120 min, and 240 min. The expression of SSB gene in the myocardium was examined by real-time PCR, and the expression of SSB protein was examined by Western blot and immunofluorescence staining. RESULTS: The expressions of SSB gene was down-regulated at early stage of ischemia. There was significant difference between 0 min and 120 min at the level of expression of SSB gene in MI group, so did that between 120 min group and NO group (P < 0.05). The expression of SSB protein at 60 min after ischemia was significantly decreased compared with that in the group of 0 min (P < 0.05). The expression of SSB protein in NI groups was significantly higher than that in MI groups at the time of 60 min and 120 min after myocardial ischemia (P < 0.05). Additionally, the expression of SSB protein was mainly located in the myocardial nucleus, myocardial plasma, and plasma membrane of partial myocardiocytes according to the result of immunofluorescence staining. CONCLUSION: SSB may participate in pathophysiologic regulation process in myocardial cells at the early stage of myocardial ischemia in rats.

Interactions of interleukin-12A and interleukin-12B polymorphisms on the risk of intracranial aneurysm.

Several lines of evidence indicate that inflammatory processes play pivotal role in the development of intracranial aneurysm (IA). Recently, polymorphisms in the interleukin-12 (IL-12) gene were shown to be associated with immune-mediated inflammatory disease. The aim of this study was to investigate the interactions of IL-12A and IL-12B polymorphisms on the risk of IA in a Chinese population. A total of 422 individuals (including 164 patients with IA and 258 controls) were involved in the study. The polymorphisms (i.e., rs2243115 and rs568408 in IL-12A and rs3212227 in IL-12B) were genotyped by polymerase chain reaction-restriction fragment length polymorphism assay and DNA sequencing. We found an association of the AC/CC genotypes and C allele of IL-12B rs3212227 with an increased risk of IA, compared with the AA genotype and A allele (AC/CC vs. AA: OR = 2.09, 95 % CI: 1.29-3.38; C vs. A: OR = 1.45, 95 % CI: 1.10-1.91). Moreover, a significant gene interaction of IL-12A and IL-12B was evident on the risk of IA, and subjects carrying variant genotypes of IL-12B rs3212227 had an increased risk of IA. In the stratified analysis by gender, the IL-12B rs3212227 AC/CC genotypes had an increased risk of IA compared with the AA genotype in male patients (AC/CC vs. AA: OR = 4.63, 95 % CI: 1.92-11.16). These findings suggest that the IL-12A and IL-12B independently and jointly be involved in the susceptibility to IA.

Association between single-nucleotide polymorphisms in interleukin-12A and risk of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterized by airflow obstruction due to chronic bronchitis, emphysema, and/or disease of small airways. It has been reported that the genetic variation may play a role in the development and severity of COPD. The purpose of this study was to investigate whether single-nucleotide polymorphisms (SNP) in interleukin (IL)-12A and IL-12B were associated with COPD in a Chinese population. The IL-12A rs2243115 and IL-12B rs3212227 polymorphisms were genotyped by performing polymerase chain reaction-restriction fragment length polymorphism in 298 patients with COPD and 346 healthy controls. We observed that the frequencies of GT and GT+GG of IL-12A rs2243115 were significantly different from TT in the COPD group and the control group (GT vs. TT: odds ratio [OR]=2.35, 95% confidence interval [CI]=1.55-3.57, p<0.001; GT+GG vs. TT: OR=2.46, 95% CI=1.63-3.71, p<0.001). These data suggest that the IL-12A rs2243115 polymorphism may contribute to genetic susceptibility to COPD in a Chinese population.

Association between pri-miR-218 polymorphism and risk of hepatocellular carcinoma in a Han Chinese population.

MicroRNAs are noncoding RNA molecules of 18-25 nucleotides that regulate gene expression at the post-transcriptional level. The aim of this study was to investigate whether pri-miR-218 rs11134527 A/G polymorphism influences the risk of hepatocellular carcinoma (HCC) or not. pri-miR-218 rs11134527 A/G was genotyped in 302 HCC patients and 513 control subjects using the polymerase chain reaction-restriction fragment length polymorphism assay. The AG genotype of pri-miR-218 rs11134527 A/G was associated with family history (p=0.018, odds ratio [OR]=2.96, 95% confidence interval [CI]: 1.16-7.56) and elevated serum α-fetoprotein (serum alpha-fetoprotein [AFP]) levels (≥20 ng/mL; p=0.009, OR=1.92, 95% CI: 1.17-3.14) in HCC patients. These findings suggested that the AG genotype of pri-miR-218 rs11134527 might relate to genetic predisposition and be involved in regulating the expression of AFP in Chinese HCC patients.

Stereological analysis of age-related changes of testicular peritubular cells in men.

This work aimed to analyze quantitative changes of peritubular cells in testes of aged men. Testicular tissues were obtained from 42 aged men with advanced prostate cancer and 16 young men with biopsy, quantitatively investigated with stereological techniques with quadrate mask grid, measured the parameters volume density (V(V)), numerical density on area (N(A)), and numerical density (N(V)) with grid test points. No significant differences were found in cell ratio, peritubular cell number per tubule, diameter of seminiferous tubules between young and old men (p>0.05). Aged men had higher pathologic assignment score than that of young men, which demonstrated more severe pathologic changes (p<0.05). Peritubular cell V(V) and pachytene germ cell V(V) increased significantly in old men compared to young men (p<0.05). Sertoli cell (SC) number per tubule in two-dimensional was significantly less in aged men than that of young men, p<0.01. Peritubular cell N(A), N(V) decreased significantly in aged men compared to young one, p<0.05. It is concluded that the stereological data of peritubular cells from three-dimensional level in testes of aged men suggest a significant decrease when compared with young men, indicating age-related changes.

[Relationship between RNA degradation and postmortem interval in mice].

OBJECTIVE: To investigate the degradation changes of beta-actin mRNA and 18S rRNA in different time points and temperature after death, and to explore the relationship between the changes and postmortem interval (PMI) in the brain of mice. METHODS: Twenty-four health adult C57BL/6 mice were randomly divided into two groups (12 each group). They were sacrificed by cervical dislocation and placed in chamber with two different temperature (4 degrees C and 37 degrees C, humidity was 80%). The mice brains were sampled at 6 different time points(immediately, 0.5h, 2h, 6h, 24h, 48h), and total brain RNA were extracted. Ct value of each sample was obtained using RT-PCR and real-time PCR technology, and beta-actin mRNA and 18S rRNA content ratio was calculated. The correlation between the content ratio and PMI was expressed using statistical regression analysis. RESULTS: At 37 degrees C, RNA degradation rate was faster than 4 degrees C, which showed that there was correlation between temperature and RNA degradation. Comparing with the stability of beta-actin mRNA, 18S rRNA was more stable. CONCLUSION: The study on degradation of beta-actin mRNA and 18S rRNA in mice brain using real time PCR technology could provide a new theoretical basis for estimation of PMI and would be supplementary to the traditional methods.