Genetic analysis of the NS genes of H5N1 avian influenza viruses isolated from sewage in poultry markets / 病毒学报

In order to investigate the transmission risk of H5N1 avian influenza viruses (AIV) from sewage in Changsha poultry markets, the evolution relationship and molecular characteristics of non-structural (NS) genes of H5N1 AIV from sewage were analyzed. Nine H5N1 AIV environmental sewage specimens were collected from Changsha poultry markets. The NS genes were amplifyed by PCR and then sequenced with TA cloning. Amino acid(aa) sequence alignment and phylogenetic tree analysis were conducted by Lasergene and Mega5 software. Eight NS genes TA cloning were constructed successfully. Phylogenetic tree indicated that they were belonged to the allele A subgroup. Aa homology analysis showed 90.1% 92.5% identity in NS1 proteins and 91.0% - 92.6% identity in NS2 proteins compared with reference viruses of the allele A (A/chicken/ Hubei/ w h/ 1999). The homologies of the amino sequences of NS1 and NS2 in this study were 93.8%-100.0% and 98.4%-100.0%, respectively. The C terminal of all eight H5N1 NS1 proteins from sewage in poultry markets carried a ESEV of PL motif and the 92 amino acids were E, furthermore, the 80 to 84aa were missed which were the characteristics of highly pathogenic AIV. The NS genes of H5N1 AIV from sewage in poultry markets have molecular characteristics of highly pathogenic and have the potential risk of H5N1 virus spreading.

Investigation of health status of workers exposed to low concentration cadmium in a zinc powder factory / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the health status of workers exposed to Cd at low concentration.</p><p><b>METHODS</b>One hundred eighteen workers of zinc powder finishing and 34 staffs were served as the exposure group and control group, respectively. The physical examination, blood cadmium, urinary cadmium, blood lead, urinary 32-microglobin, urine creatine, chest film, pulmonary function , pure tone teat and were detected for all subjects.</p><p><b>RESULTS</b>Twelve air samples from 6 monitoring points in workshop were detected, the air Cd concentrations were 0.002-0.015 mg/m³, which were under the national limit of occupational exposure. In exposure group, the rates of exceeding standards of blood Cd and urinary Cd were 65.25% and 38.16%, respectively, the rate of exceeding standards of urinary Cd for two times was 27.12%, the rate of exceeding standard of urine Cd for two times plus the positive urinary 32-microglobin was 2.54 %. In control group, the rates of exceeding national standard of blood Cd was 26.47 %, but the values of urinary Cd were normal. In exposure group, the rate of exceeding standards of urinary Cd increased with the service length. Smoking could enhance the rates of exceeding standards of blood Cd and urinary Cd.</p><p><b>CONCLUSION</b>In zinc powder finishing, the low-concentration cadmium exposure could cause the occupational cadmium poisoning, the comprehensive protection measures can reduce the occupational cadmium poisoning. It is suggested that the limits of occupational exposure to cadmium should be declined.</p>

Preparation of enamel matrix proteins controlled release microspheres and their biological effects on the proliferation and differentiation of human periodontal ligament cells in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To prepare enamel matrix proteins (EMPs) loaded dextran-based hydrogel microspheres (EMPs-dex-MPs), and to evaluate their EMPs controlled release property and their biological effects on the proliferation and differentiation of human periodontal ligament cells (PDLCs) in vitro.</p><p><b>METHODS</b>Using dimethylbenzene as the oil phase, EMPs-dex-MPs were achieved by emulsion-chemical crosslinking technique. The process of the recombination preparation was optimized by orthogonal factorization method. The configuration and size of EMPs-dex-MPs were determined by scanning electron microscope. The EMPs loading content and encapsulation rate of EMPs-dex-MPs, and their biodegradation characteristic were studied by routine analysis methods. Dynamic dialysis method was used to determine the release characteristic of EMPs-dex-MPs in vitro and its influencing factors. The proliferation of cultured PDLCs was measured by MTF method and the differentiation of PDLCs was measured by their alkaline phosphatase (ALP) activities.</p><p><b>RESULTS</b>The results showed that EMPs-dex-MPs were homogenous and stable with the average diameter 25 microm, and the EMPs loading content was (32.8 +/- 1.2)%, the encapsulation rate was (78.9 +/- 1.0)%. Under 9% physiological saline solution contained a very thimbleful quantity of dextranase EMPs-dex-MPs could be biodegraded completely during about 40 days. The in vitro experiments showed that about 80% of EMPs could be released out in 20 days. Using EMPs-dex-MPs could enhance the proliferation responses and ALP activities of PDLCs more than 12 days.</p><p><b>CONCLUSION</b>As a new sustained release system of growth factors, the dex-MPs is stable, workable and biodegradable. EMPs-dex-MPs, whose drug release can be controlled by preparation technique, may be more effective in promoting periodontal tissue regeneration.</p>