Feasibility assessment for the observation of murine retinal vessel by retro-orbital injection of fluorescein isothiocyanate-dextran / 中华实验眼科杂志

Background The incidence of retinal vascular diseases increase annually,such as diabetic retinopathy,retinopathy of prematurity and age-related macular degeneration.The key of treatment for these diseases is how to evaluate retinal vascular change effectively and objectively.Retro-orbital injection of fluorescein isothiocyanatedextran (FITC-dextran) is a simple and effective method for observing C57BL/6J mouse retinal vessels.But,whether it is suitable for other mice and rats is seldom reported.Objective This experiment was to assess the feasibility of the observation of retinal vessels by retro-orbital injection of FITC-dextran in different genus of mouse and offer the reference for relevant study.Methods Twelve animals of C57BL/6J mice,Kunming mice,SD rats and Wistar rats were selected,respectively and divided into the experimental group and control group at average.The right eyes of the animals of the experimental group received the retro-orbital injection of 9 ml/kg FITC-dextran,and the right eyes of animals of the control group received PBS solution at the same volume and way.All the animals were sacrificed 10 seconds after injection and both eyes of each animal were obtained for retinal stretched preparation.The retrobulbar tissue and whole-mount retina were viewed under a fluorescence microscope.The use of the animals complied with Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Retinal blood vessels labeled by FITC-dextran could be observed in both eyes of C57BL/6J mice and Kunming mice to present with a green fluorescence in experimental group under a fluorescence microscope,but no any fluorescence-labeled retinal blood vessel was exhibited in the control mice.The retinal blood vessel could not be observed in all eyes of SD rats and Wistar rats after the injection of FITC-dextran both in the experimental group and the control group under a fluorescence microscope.The surrounding tissues of the right eyes of mice and rats dyed with green fluorescence of FITC-dextran in the experimental group,however,green fluorescence could not be seen in the surrounding tissues of the left eyes of mice and rats.Conclusions Retro-orbital injection of FITC-dextran is a suitable method of observing the retinal vessels of mouse but not rat.

Bioengineering plant resistance to abiotic stresses by the global calcium signal system.

Considerable progresses have taken place both in the methodology available to study changes in intracellular cytosolic calcium and in our understanding of calcium signaling cascades. It is generally accepted that the global calcium signal system functions importantly in coping with plant abiotic stresses, especially drought stress, which has been proved further by the recent transgenic and molecular breeding reports under soil water deficits. In plant cells, calcium plays roles as a universal transducer coupling a wide range of extracellular stimuli with intracellular responses. Different extracellular stimuli trigger specific calcium signatures: dynamics, amplitude and duration of calcium transients specify the nature, implication and intensity of stimuli. Calcium-binding proteins (sensors) play a critical role in decoding calcium signatures and transducing signals by activating specific targets and corresponding metabolic pathways. Calmodulin (CAM) is a calcium sensor known to regulate the activity of many mammalian proteins, whose targets in plants are now being identified. Higher plants possess a rapidly growing list of CAM targets with a variety of cellular functions. Nevertheless, many targets appear to be unique to higher plant cells and remain characterized, calling for a concerted effort from plant and animal scientists to elucidate their functions. To date, three major classes of plant calcium signals encoding elements in the calcium signal system, including calcium-permeable ion channels,Ca(2)+/ H(+) antiporters and Ca(2)+-ATPases, are responsible for drought stress signal transduction directly or indirectly. This review summarizes the current knowledge of calcium signals involved in plant abiotic stresses and presents suggestions for future focus areas of study.

Application of purified recombinant outer membrane lipoprotein LipL32 in detecting antibodies among leptospirosis cases / 中华流行病学杂志

Objective To establish recombinant outer membrane lipoprotein LipL32-based antibody detection assays in identifying leptospirosis. Methods Recombinant leptospiral outer membrane protein LipL32 was obtained by genetic engineering method. This purified protein was used in the indirect and sandwich ELISA assays to test the antibodies in sera of human beings and rats, and the results were compared with those obtained by microscopy agglutination test (MAT) and imported ELISA kit. Results When the acute and convalescent phase specimens from 9 leptospiral patients were tested, the detected rates of three ELISAs were similar to the MAT. Among the 45 probable cases which MAT showed positive, 32 (71.11%) samples were positive by r32-I-ELISA, 36(80.00%) by r32-S-ELISA,while 28.89% (13/45) samples were positive and 55.56% (25/45)were suspicious by D.A.I-ELISA. The specificity of r32-I-ELISA and r32-S-ELISA were 97.10 % (67/69) for 69 specimens. 43 healthy specimens were negative by both r32-I-ELISA and r32-S-ELISA, 14 healthy specimens were negative by D.A.I-ELISA. Among 16 non-leptospirosis patients, two specimens were positive by r32-I-ELISA and r32-S-ELISA, D.A.I-ELISA and identified one positive specimen, while 12 specimens were suspicious by D.A.I-ELISA. For 10 syphilis specimens, data obtained through three ELISAs were in consistent with that by MAT. A sandwiched ELISA, using rLipL32 protein as the antigen was developed to detect rat sera. Considering MAT as standard test, the sensitivity and specificity were 86.75 % (131/151), 99.19 % (122/123) respectively with coincidence rate as 92.34% (253/274). Conclusion The recombinant protein LipL32 had high immunoresctivity and could be used as an antigen for the detection of panthogenic leptospirosis. In summary, the novel sandwiched ELISA with rLipL32 showed similar sensitivity and specificity to that of MAT in the antibody detection of rat leptospirosis. It was suitable for large scales field sero-epidemiological studies.

Study on the epidemiology and etiologic agent of Dengue fever outbreaks in Fuzhou in 2004 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the epidemiology and etiologic characteristics of a Dengue fever outbreak in Fuzhou from the beginning of September to the end of October in 2004 in order to understand the source of infection.</p><p><b>METHODS</b>Data on descriptive epidemiology was collected to study the characteristics and related factors to the epidemic. Dengue virus was isolated through the use of C6/36 cell line while viral serotypes were identified by indirect immunofluorecent assay with type-specific monoclonal antibody. The sources of infection were traced by nucleotide sequencing.</p><p><b>RESULTS</b>During the epidemic, 93 cases occured consistently with the region entomoplily growth and decay. The viruses of 6 strains isolated from 10 patients' blood specimens were identified as dengue virus type 1. Phylogenetic evidence suggested that the viral isolate had high genetic relation with the isolates from Kampuchea (DENV-1/KHM/2001; GenBank Accession No. L0904278).</p><p><b>CONCLUSION</b>The epidemic was caused by introduction of patients migrating into Fuzhou.</p>