The isolated vessel elements from the xylem in Chinese Sarcandra species were observed by scanning electron microscope and optical microscope. The vessel elements with simple pits or (and) bor dered pits or (and) scalariform pits or (and) circular-scalariform pits in their secondary walls are 1200-1900 in length and all have scalariform multiperforation plates in which the numbers of bars are between 60 to 160.

Objective To study the effect of soluble, refolded, recombinant extracellular domain of the human Fc gamma receptor Ⅱ a (huFcγRⅡa) on the binding of human IgG to cells. Methods Extra-cellular domain of the huFcγRⅡ a gene was amplified from recombinant plasmid pe3huR Ⅱ by PCR and then cloned into pET-28a vector. The recombinant plasmid pETshuR Ⅱ was transformed into E. coli BL21 (DE3) after identified by PCR and doubly digested. The inclusion bodies of fusion protein were extracted and purified by washing, dissolved in 6 mol/L guanidine buffer, and refolded by rapid dilution technique. The refolding protein activity was tested by ELISA and flow cytometry. Results Extraceilular domain of the huFcγRⅡa gene was successfully cloned into pET-28a. The results of SDS-PAGE showed that the molecular mass (Mr) of the expressed protein was 24.8 × 103, and the expression rate was 30%. The purity of recom-binant shuR Ⅱ was up to 90% after washing. ELISA showed that the recombinant shuR Ⅱ was able to bind human IgG in a dose dependent manner, shuRⅡ could competitively inhibit the binding of human IgG to huFcγRⅡa expressed on the surface of COS-7 cells by flow cytometry. Conclusion The results demon-strate that it is possible to obtain large quantities of recombinant shuR Ⅱ which has comparable binding prep-erties to those of the whole membrane bound huFcγR Ⅱ a.

Objective To evaluate the efficiency and safety of genipin collagen crosslinking (G-CXL) on rabbit corneas in vivo.Methods Forty healthy New Zealand white rabbits were randomly divided into 0.20％ G-CXL,0.25％ G-CXL,standard UVA-CXL and normal control group.And the right eyes were treated in different grouping.No procedures were performed in the normal control group.The corneal curvature (Km) and central corneal thickness (CCT) of right eyes were evaluated before,7 days and 14 days after crosslinking treatment.Cornea strips were harvested from the right eyes and tensile strain measurements were performed 7 days and 14 days after crosslinking treatment.The structure of corneal stroma was observed under light microscope (LM) and transmission electron microscope (TEM).Results No statistically significant differences in Km were observed among different groups or different timepoints (Fgroup =0.301,P=0.825;Ftime =1.287,P=0.284).Significant difference in CCTs was noticed among different time pionts (Ftime =3.786,P =0.029).Compared with preoperative,the CCTs of all the groups were significantly increased 7 days after crosslinking (all at P＜0.05).No significant difference in CCT was found among the groups (Fgroup =0.557,P=0.646).Seven days after crosslinking treatment,the Young's modulus at 10％ strain was (1 1.96±5.74),(21.24±6.77),(18.76±3.34) and (11.56±4.37) MPa in 0.20％ G-CXL group,0.25％ G-CXL group,UVA-CXL group and normal control group,respectively;the stress at 10％ strain was (0.68 ±0.24),(1.20 ± 0.25),(1.0l ± 0.30) and (0.69 ± 0.26) MPa,respectively;the Young's modulus and stress in 0.25％ G-CXL group was significantly increased when compared with those in 0.20％ G-CXL and normal control group (both at P＜0.05).No significant difference in Young's modulus and stress was observed between 0.25％ G-CXL group and UVA-CXL group (all at P＞0.05).Forteen days after crosslinking treatment,Young's modulus at 10％strain was (16.65±3.19),(19.12±2.39),(22.83 ±4.38) and (12.70±2.72)MPa in 0.20％ G-CXL group,0.25％ G-CXL group,UVA-CXL group and normal control group,respectively;stress at 10％ strain was (0.83 ±0.12),(0.97±0.04),(1.23±0.30) and (0.65±0.20) MPa,respectively;the Young's modulus and stress in UVA-CXL group was significantly increased,when compared with 0.20％ G-CXL group and normal control group (all at P＜0.05).Statistical significance of stress was observed between 0.25％ G-CXL group and UVA-CXL group (P =0.046).There is no significant difference in Young's modulus between 0.25％ G-CXL and UVA-CXL group (P =0.090).LM showed the reduction of keratocytes existed in superficial stroma of 0.20％ and 0.25 ％ G-CXL groups,while the reduction of keratocyte was found in anterior and intermediate stroma of UVA-CXL group.In 0.20％ and 0.25％ G-CXL groups,the ultrastructure of keratocytes was normal except vacuole in some keratocytes.Keratocytes apoptosis was noticed in UVA-CXL group and keratocytes was normal in deep stroma under TEM.Conclusions 0.25％ has a similar biomechanics effect when compared to UVA-CXL.Moreover,histological observation proves a better safety of G-CXL in comparison of UVA-CXL.

A simple and rapid immunochromatographic test strip incorporating a colloidal gold-labeled recombinant Nsp7 antigen probe was successfully developed for the detection of anti-porcine reproductive and respiratory syndrome virus (PRRSV) antibodies in swine. Recombinant Nsp7 protein of PRRSV labeled with colloidal gold was dispensed on a conjugate pad for use as the detector. Staphylococcal protein A and purified porcine anti-Nsp7 antibodies were blotted on a nitrocellulose membrane to form test and control lines, respectively. A comparison of the strip with standard diagnostic tests, enzyme-linked immunosorbent assays and immunoperoxidase monolayer assay, was also performed. The immunochromatographic test strip was shown to be of high specificity and sensitivity. Furthermore, the strip assay is rapid and easy to perform with no requirement for professional-level skills or equipment. It is suggested that the immunochromatographic test strip can be used to quickly and accurately detect PRRSV antibody and to be suitable for diagnostic purposes in the field.
Antibodies* ; Collodion ; Colloids ; Diagnostic Tests, Routine ; Enzyme-Linked Immunosorbent Assay ; Gold Colloid ; Immunochromatography ; Membranes ; Porcine Reproductive and Respiratory Syndrome* ; Porcine respiratory and reproductive syndrome virus* ; Sensitivity and Specificity ; Staphylococcal Protein A ; Swine

Background Keratoconus is a chronic and progressive non-inflammatory ectatic disorder characterized by corneal thinning and irregular corneal topography,and its pathgenesis is a hot topic.A suitable animal model of keratoconus is still lacking,which limits the progress of relevant research.Corneal ectasia is a main anatomical basis of keratoconus,so we assume that keratoconus model could be constructed by simulating corneal ectasia.Objective This study was to investigate the influence of collagenase type Ⅱ on biomechanical responses detected by corneal visualization Scheimpflug technology (Corvis ST) and the feasibility of construction of rabbit model of corneal ectasia using coliagenase type Ⅱ.Methods This study protocol was approved by Ethic Committee of Peking University First Hospital and followed the Statement about experimental animal use and care from Association for Research in Vision and Ophthalmology (ARVO).Keratectasia models were established in 10 right eyes of 10 New Zealand white rabbits by soaking 8 mm-diameter central cornea using collagenase type Ⅱ solution prepared by PBS solution containing 15％ dextran (200 μl of 5 mg/ml) for 30 minutes after epithelial debridement,and only 200 μl PBS solution containing 15％ dextran was used in the same way in the left eyes as controls.The average corneal curvature (Km) and central corneal thickness (CCT) were measured with hand-held electronic corneal curvature meter and corneal ultra-sonic pachymetry respectively before modeling and 14 days after modeling.Corneal biomechanical parameters and intraocular pressure were measured in vivo by using Corvis ST at day 14 after modeling.The rabbits were sacrificed at day 14 after modeling,and corneal sections were prepared for hematoxylineosin staining and transmission electron microscopic examination.Results There were no significant differences in Km and C CT between model group and control group before modeling (Km:[48.28±2.29] D vs.[48.82± 1.63] D;CCT:[356.50± 19.13] μm vs.[356.20±21.66] μm;both at P＞0.05).The Km increased to (48.87±2.27) D and CCT decreased to (340.40±19.84)μm at day 14 after modeling,which were significantly different from (46.86±1.47) D and (367.80±23.38)μm (both at P＜0.01).The maximal deformation amplitude of model group and control group was (1.25±0.07) mm and (1.15 ±0.13) mm,respectively,showing a considerable difference between them (t=2.65,P＜0.05).No significant differences were found in applanation 1/2 time,applanation 1/2 length,applanation velocity,radius of curvature and peak distance between the two groups (all at P＞0.05).The morphology and ultrastructure examinations revealed that the arrangement of collagen fibers was loose and disorder and the interfiber space was enlarged in comparison with control group.Conclusions Collagenase type Ⅱ can lower corneal biomechanical properties.Soaking of cornea with collagenase type Ⅱ may be a potential way to establish a keratectasia animal model.