Measurement and analysis on operating force from Chinese young males / 医用生物力学

Objective To establish the operating force database of Chinese young males and provide basis information for the design of operating force in working place. Methods Anthropometric parameters of 843 Chinese young males from northeast, north, northwest, southwest, southeast, central and south China were collected, including the back force, hand twisting force, arm forces in four exerting directions and with various elbow angles. The data were statistically analyzed and compared with related researches in China and abroad. ResultsFor arm forces in four exerting directions, the pushing force was greater than the pulling force, and the inward force was greater than the outward force. The pushing force was the largest and the outside outward force was the smallest. With the increase of the elbow angle, the pushing and pulling forces were increased significantly, while the inward and outward forces were decreased significantly. A significant correlation existed among the operating forces. There was significant correlation between the operating force and body weight, while weak correlation was found between the operating forces and anthropometric parameters. Operating forces of Chinese young males were relatively smaller than those of the Westerns. Conclusions By sampling on a national scale, the operating force database was established for Chinese young males. This study provides the basic data for the design of operating force in man-machine system and could be also used as reference for ergonomics researchers, occupational health workers and rehabilitation researchers.

Detecting caries susceptible population in children with gtfB oligonucleotide probe / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish a quick, exact and inexpensive method to detect caries susceptibility in children.</p><p><b>METHODS</b>125 caries free children, aged 3-4 years, were randomly sampled. A combination of polymerase chain reaction (PCR) and gtfB oligonucleotide probe hybridization method was used to detect Streptococcus mutans in saliva. The participants were followed up for a year and the clinical examination results were compared with the laboratory results. The perspective study was used to evaluate the detecting approach.</p><p><b>RESULTS</b>When the combination of PCR and hybridization method was used to detect caries susceptibility of the sample, the predictive sensitivity, predictive specificity and predictive reliability were all increased to 69.2%, 46.8% and 54.3%, respectively as compared to only PCR, which were 56.4%, 44.2% and 48.3%, respectively. The samples with both the positive and negative results of hybridization detection had caries clinically, but the dmft index and prevalence were higher in the positive (dmft was 2.15 +/- 0.86, and the prevalence was 23.28%) than in the negative(dmft was 1.58 +/- 0.51, and the prevalence was 10.34%) which was statistically significant (P < 0.05).</p><p><b>CONCLUSION</b>The probe was found to be quite potential in detecting caries susceptibility, but the predictive specificity and predictive reliability values were not significant.</p>

Alteration of gene expression during nasopharyngeal carcinogenesis revealed by oligonucleotide microarray after microdissection of tumor tissue and normal epithelia from nasopharynx / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Microarray and microdissection techniques were being used for many applications to study the carcinogenesis of some human tumors. But seldom studies had hitherto combined these two techniques to study carcinogenesis mechanism of nasopharyngeal carcinoma (NPC). To identify a set of genes involved in the carcinogenesis and development of NPC, we used the microdissected homogeneous NPC tissue cells and the pure normal epithelium pillar cells to construct the whole human genome expression profiles.</p><p><b>METHODS</b>We preserved the tissue samples from nasopharynx of 18 patients (including 13 samples of NPC and 5 samples of normal or inflammatory mucous tissue samples from nasopharynx) in RNAlater Stabilization Reagent. The tissue samples were microdissected to harvest the homogeneous tissue cells, then total RNA was isolated from them. The sufficient antisense RNA (aRNA) was amplified from these total RNA. HG-U133.Plus.2.0 GeneChip was used to construct the human whole genome expression profiling of each sample. Differential patterns of expression of genes correlated with the carcinogenesis, classification and progression of NPC were identified with comparing the expression profiling data respectively in leave one out cross-validation analysis. Correlation between aRNA expression measured by the microarrays and semi-quantitative reverse transcription polymerase chain reaction (sqRT-PCR) were also ascertained, and found that hybridization results were validated in all of the 18 patients.</p><p><b>RESULTS</b>Differential patterns of expression of 127 genes correlated with the carcinogenesis (A P value less than 0.001 with the 2-fold differentiated expression between case group and control group) of the NPC were filtered. The top most up-regulated and down-regulated 8 genes by the way of permutation test were also selected and listed in the paper. Expression of genes E2F6 and TSPAN-1 was identified using aRNA by sqRT-PCR and showed that there was significant difference between the average value of case groups and that of control group respectively (t = 2.170, df = 16, P = 0.045 and t = -2.946, df = 16, P = 0.009).</p><p><b>CONCLUSIONS</b>We had identified some genes which could be the molecular marker during the carcinogenesis and the development of the NPC. The genes which selected from the different subgroups seemed to be implicated for the diagnosis,classification, and progression of NPC, and provided important insights into their underlying biology.</p>

Advances in the RNA-directed DNA methylation in plants / 生物工程学报

The RNA-directed DNA Methylation (RdDM) is one type of epigenetic modification which was firstly discovered in plant. RdDM can directly cause DNA modifications of the genome through RNA-DNA interactions. In plant, both of RdDM and mRNA degradation induced by siRNA can silence sequence specific genes through RNA. They play very significant roles in chromosome rearrangement, defence of virus invasion, regulation of gene expression and many processes of plant development. However, the mechanisms of RdDM are still unclear. In this paper the basic characteristics of RdDM were briefly summarized and advances in studies on mechanisms of RdDM were reviewed. These include the kinds of DNA methyltransferases and their functional mechanisms in RdDM, the relationships between DNA methylation and chromatin modification, and important proteins involved in the RdDM process. In plants, RdDM may occur at both the transcriptional and post-transcriptionnal levels, both of which induce gene silencing. Methylation of the target gene promoter correlates with transcriptional gene silencing (TGS) whereas methylation of the coding sequence is associated with post-transcriptional gene silencing (PTGS). RdDM and RNAi all depend on the similar siRNA and enzymes, such as DCL3, RdR2, SDE4 and AGO4. There are at least three kinds of DNA methyltransferases, DRM1/2, MET1 and CMT3, in pants. They can interact with and modifies all cytidines within the DNA regions homologous to RNA sequence. Furthermore, methylation of lysine 9 in Histone H3 can affect the methylation of cytidines.

Expression of NASG gene and its role in human nasopharyngeal homogenous tissue cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The NASG gene has been confirmed as a tumor-suppressor gene candidate related to nasopharyngeal carcinoma (NPC) by previous studies. We further investigated the expression and the role of NASG in the homogeneous tissue cells by microdissecting the samples of tissue from human NPC, and introduced a new way to study the expression of specific genes in tumor tissue.</p><p><b>METHODS</b>The RNAlater reagent was used to preserve the samples of tissue from the nasopharynx of NPC patients. The samples were microdissected to harvest the homogeneous tissue cells and then total RNA was isolated from them. The antisense RNA (aRNA) was amplified from the total RNA by "in vitro transcription (IVT)". We investigated NASG expression in the homogeneous tumor cells of NPC (22 samples) and compared it with that in the pure epithelial pillar cells of normal nasopharyngeal (10 samples) by semi-quantitative reverse transcription-polymerase chain reaction (sqRT-PCR).</p><p><b>RESULTS</b>The high quality total RNA could be harvested from the microdissected homogeneous tissue cells of the nasopharynx, then sufficient aRNA was derived from it. NASG gene expression was identified using aRNA by sqRT-PCR and showed that there was significant difference between the average value of case groups and that of control group (t = -5.275, df = 30, P < 0.001). The NASG gene in the subgroups WHOII tended to express lower levels than those in the subgroup WHOIII although this difference was not statistically significant (t = -1.584, df = 20, P = 0.129 > 0.05).</p><p><b>CONCLUSIONS</b>Microdissection was an effective method to obtain the homogeneous tissue cells of nasopharyngeal tissue (including the samples of NPC and non-NPC) in our study. Sufficient aRNA from amplifying total RNA could be used in sqRT-PCR to analyse the expression of NASG in the pure tissue cells. NASG should be a tumor-suppression gene candidate regarding to NPC.</p>

Preliminary biomarker related to nasopharyngeal carcinoma filtered from the whole genome expression profiling involved in microdissection nasopharyngeal tissues / 中南大学学报(医学版)

OBJECTIVE@#To filter biomarkers of nasopharyngeal carcinoma (NPC) by constructing the homogenesis tissue gene expression profiling with the whole human genome GeneChip.@*METHODS@#The epithelium cells of the homogenesis NPC and the pure nasopharyngeal normal tissues microdissected from nasopharyngeal biopsy which was preserved in the RNAlater were used to isolate RNA and then to harvest the aRNA through in vitro transcription, and aRNA prober was labled to hybridize to HG-U133. plus 2.0, so the expression profiling of each homogenesis tissue could be constructed.@*RESULTS@#Some candidate biomarker genes related to the tumorigenesis of NPC had been filtered by comparing the expression profiling of NPC samples with the expression profiling of normal nasopharyngeal epithelia samples. Any genes regarding the metastasis of NPC might have been selected by comparing the expression profiling of no-metastasis samples with those of the metastasis samples.@*CONCLUSION@#Using the whole genome GeneChip to construct the expression profiling for the microdissected homogenesis tissue is effective to filter the candidate biomarker genes.

Effect of drinking water change upon the dental fluorosis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To assess changes in prevalence and degree of dental fluorosis in individuals born before and after the introduction of water with 1.2 mg/L fluoride instead of water with 2.0-10.0 mg/L fluoride previously used in Da Li County in China.</p><p><b>METHODS</b>The students (n = 291) were divided into 2 groups. The dental fluorosis was scored according to Dean's classification. The statistical analysis was performed by t-test and chi(2) tests.</p><p><b>RESULTS</b>The prevalence of dental fluorosis was significantly lower in the group of the students drinking water from the new well (group 1) as compared to the group of the students drinking the old water (group 2), i.e. 48.8% versus 87.2% (P < 0.01). The percentage of moderate to very severe fluorosis was 13.9% and 0 in group 1 as compared to 32.0% and 8.8% in group 2. The fluorosis community index (FCI), defined by Dean, in group 1 and 2 was medium (1.01) and marked (2.12) respectively.</p><p><b>CONCLUSIONS</b>The results showed that: (1) The prevalence of dental fluorosis was significantly lowered by the new source of drinking water. (2) Drinking water, even with 1.2 mg/L fluoride, may cause dental fluorosis during the period of tooth mineralization.</p>