The porcine reproductive and respiratory syndrome virus (PRRSV) can cause reproductive barriers in breeding pigs and respiratory symptoms in piglets. In this review, we summarize research progress of the infection and replication mechanisms of the PRRSV. We also review the virulence determinants of the PRRSV. All these fundamental studies are important for the control and elimination of the PRRSV.
Animals ; Porcine Reproductive and Respiratory Syndrome ; virology ; Porcine respiratory and reproductive syndrome virus ; genetics ; pathogenicity ; physiology ; Swine ; Virulence ; Virus Replication

A secretive expression vector of Pichia pastoris system which can be used for the direct cloning of PCR products was constructed,and was verified through the expression of recombinant cellobiohydrolase II in Pichia pastoris.A randomly selected fragment was amplified with properly designed primers by PCR.The XhoI and Eam1105Ⅰ restriction sites were included in the 5'end of the fragment,and the Eam1105Ⅰ and XbaI restriction sites were included in its 3'end.The PCR amplified product was inserted into the P.pastoris expression plasmid pPICZ?A through XhoI and XbaI restriction sites and the resultant plasmid was digested with Eam1105Ⅰ,and lastly the big fragment was recovered,generating the P.pastoris expressive Tvector pPICZ?T.Then the cellobiohydrolase II of T.reesei was successfully expressed in P.pastoris with this expressive Tvector.Such results indicated that the constructed expression Tvector was convenient for PCR product cloning,and was effective for heterologous protein expression in P.pastoris.On the other hand,the application of the expression Tvector avoided the introduction of additional amino acids at the Nterminus of the expressed protein,which generally occurred when normal expression vectors were used in secretive expression system.

Objective: To study the effect of palate repair operation on middle ear function. Methods: Cleft palate was repaired with double-opposing Z-plasty(DOZ) in 20 cases and with routin method (RM ) in 23 cases. Secretory otitismedia (SOM), high negative pressure (HNP), stapedial reflex(SR) and low acoustic compliance (LAC) were determined 3d before and 6 months after operation respectively. Results: Of the total 86 ears, before operation the persentages of SOM, HNP, SR and LAC were 61. 63, 75. 58, 29. 07 and 65. 15; after operation those were 31.39, 43.02, 66.28 and 33.72, respectively. Of the 40 ears of the cases treated with DOZ the persentages of those were 20.00, 27.50, 72.50 and 25.00) while of the 46 ears of the cases treated with RM those were 41.30, 56.52, 60.87 and 41.30 respectivellly. Conclusion: Middle ear function can be improved by palate repairs surgery, better results may be achieved with double opposing Z-plasty technique.

Objective To research the effects of bosentan in on unilateral ureteral obstruction (UUO) rats. Methods Wistar rats were randomly divided into three groups. UUO group was subjected to complete ligation of left ureter, sham operation group with sham operation was used as control. Bosenten group was subjected to complete ligation of left ureter and to stomach with bosentan suspension. Three groups were killed at 5,10,15,20 d. We examined renal pathological changes and the expressions of transforming growth factor-?1 (TGF-?1) in kidney of all rats using immunohistochemistry analisis method. The plasma and ureteral obstructive kidney urinary concentration of endothelin - 1 (ET - 1) was determined by radioimmunoassay. Results In Bos and UUO groups, the urinary concentration of ET - 1 increased substantially and the expression of TGF - ?1 were much higher than those in the S group. At the same time.tubulointerstitial fibrosis was present in the kidney of rats in Bos and UUO group. But the expression of TGF- ?1 and tubu-lointerstitial fibrosis in Bos group were lower than those of UUO group. Conclusion Bosentan can effectively amelirate tubulointerstitial fibrosis in rats with UUO by ET and TGF - ?1 machanism.

Objective To determine the expression of endothelin in kidneys of rats with unilateral ureteral obstruction (UUO). Methods Rats were evenly divided into two groups. Some were subjected to complete ligation of left ureter and the others with sham operation were used as control group.Four weeks later, we examined the mRNA expressions of ET-1 in kidneys of all these rats using reverse transcription-polymerase chain reaction (RT-PCR) method.The immunohistochemistry analysis was carried out to investigate the protein level of ET-1. The urinary concentration of ET-1 was determined by radioimmunoassay.Results In UUO group, the urinary concentration of ET-1 increased substantially;both gene expression and protein level of ET-1 were much higher than those in control group. At the same time, tubulointerstitial fibrosis was present in the kidneys of rats with UUO. Conclusion ET-1 is involved in the pathogenesis of the injury of UUO.

Objective To study a simple and manual contrast board in Double Contrast Examination,so as to decrease labor intensity and the X-ray influence to the work staff.Methods The integrated design consisted of two parts:filled gas and oppressive container.The gas and Barium was injected into the large intestine by manual control and its volume may be adjusted casually according to the requirement.Results It is proved in clinical application that the design is reasonable,the structure is simple and the operation is convenient.Conclusion The device makes the relationship between medical staff and patients more harmonious.It worth popularizing.

Child, Preschool ; China ; epidemiology ; Humans ; Infant ; Infant, Newborn ; Language Development ; Sampling Studies

Adult ; Dust ; Female ; Glass ; Humans ; Male ; Middle Aged ; Occupational Diseases ; epidemiology ; Prevalence ; Skin Diseases ; epidemiology ; Young Adult

Objective To study the chemical constituents of the dried roots of Lepidium meyenii cultivated in Lijiang. Methods The samples were extracted by 90% alcohol, and then isolated by silica column, MCI, and HPLC. The structures of the isolated compounds were elucidated by NMR techniques including 2D NMR such as HSQC, HMBC, and COSY. The cytotoxic activity of the new compound against five cell lines (NB4, A549, PC3, SHSY5Y, and MCF7) was evaluated by MTT methods. Results Three macamides were isolated and identified as N-(3,4-dimethoxybenzyl) hexadec-9Z-enamide (1), N-benzyl-13-oxo-9E,11E-octadecadienamide (2) and N-(3,4-dimethoxybenzyl)-hexadecanamide (3) from this plant. Conclusion Compound 1 is a new compound named macalepidiumide A and shows no significant cytotoxic activity.

Objective To explore the alterations of protein phosphatase-2A (PP-2A) in lymphocytes in mild cognition impairment (MCI) and Alzheimer's disease (AD).Methods The activity PP-2A of was measured by ~(32)p liquid seintillography for incorporated radioactivity in control group(n=11) , the MCI group(n=11),and the AD group(n=11).The expression of PP-2A was determined by Western blot.Results In the control group,the activity of PP-2A (1.01?0.09) and the expression of PP-2A (0.96?0.07) were high while in the MCI group,the activity of PP-2A (0.71?0.12) and the expression of PP-2A (0.80?0.05) were decreased (both P