Biomedical subjects

X Yi

Publications and source records attributed to X Yi.

At least 55 records · Page 3Linked to original sources

PubMed1998

[Observations on rat's muscle at various postmortem intervals by scanning electron microscopy].

The aim of this study was to observe the morphological changes of muscle in the process of rigor mortis. The quadriceps of 40 rats at various postmortem intervals were observed under the scanning electron microscope (SEM) and the light microscope by phosphtungstic acid-haematoxylin staining. The results showed that the striations of muscle were blurred within 4 hours, but they became apparent from 6 hours to 24 hours after death. The authors suggest that this phenomenon be associated with the increased resistance of muscle against the postmortal changes. The observations by scanning electron microscopy and light microscopy have revealed that the muscles do contract in the process of rigor mortis because the distance between two Z lines shortens and the I band narrows, compared with those in anaesthetised animals. The basic biochemical process for the formation of rigor mortis is the same as that of muscle contraction except that the former happens postmortem and the latter antemortem.

Animals↗

PubMed1998

[Schistosoma japonicum: purification and diagnostic application of recombinant 32 kD antigen].

Separation and purification of rSj32 were carried out with SDS-PAGE and electroelution technique. The purified rSj32, AWA and SEA were used to examine sera of patients with schistosomiasis, healthy individuals and patients with other parasitic diseases by ELISA. The results showed that the molecule weight of rSj32 was 37 kD. The sensitivity and specificity of rSj32 as a coating antigen in ELISA were as good as those of AWA and SEA. It is suggested that rSj32 antigen is a potential antigen for immunodiagnosis of schistosomiasis japonica.

Animals↗

PubMed1998

[Relationship between dental severe attrition and the temporomandibular glenoid morphology].

This study used the indices of the temporomandibular glenoid and posterior slope of the eminence by tomography to determine the effect of severe dental attrition on temporomandibular glenoid morphology. The results showed: the temporomandibular glenoid indexes in the group with dental severe attrition and in the control group were respectively 91.49 +/- 8.20 and 92.54 +/- 8.38 (P > 0.05), and the indices of posterior slope of the eminence were 49.79 +/- 5.84 and 50.38 +/- 4.58 (P > 0.05), the difference was not statistical. It was concluded that severe dental attrition would not certainly cause abnormal temporomandibular glenoid.

Cephalometry↗

PubMed1998

Immunoscreening of Schistosoma japonicum egg cDNA library.

AIM: To screen and identify genes encoding vaccine candidates and molecules with diagnostic potential from S. japonicum (S. j) egg cDNA library. METHODS: S. j egg cDNA library was screened by sera from SEA-immunized rabbits. Positive clones were identified after three rounds of screening and were excised automatically in vivo with helper phage. Products of PCR were used to detect insert sizes by agarose gel electrophoresis. DNA samples were obtained by purification using mini-prep kit. Automatic sequencing was carried out and the sequence data were analysed using GCG software. RESULTS: Twelve clones were identified as positive and the inserts were around 1.2 kb in size. Compared with DNA sequences in GenBank, eight clones were homologous to a 70 kDa S. j heatshock protein(S. j HsP70). C18 exhibited 97.8% homology with S. j23. C22 and C23 shared 82.4% and 89.5% homology with S. j calreticulin, respectively. C12 was homologous to S. mansoni(S. m.) immunophilin. CONCLUSION: This paper first reported the results of immunoscreening S. j egg cDNA library by anti-SEA sera. Twelve positive clones were found to be related to protective immunity and/or immunodiagnosis of schistosomiasis.

Animals↗

PubMed1998

[Cross-protection against Schistosoma japonicum infection in mice immunized with Trichinella spiralis muscle larva antigen].

AIM: To explore the cross-protection against S. japonicum cercaria challenge in mice immunized with T. spiralis larva antigen. METHODS: Groups of BALB/c mice were immunized with 4 preparations of T. spiralis larva antigen, respectively. Vaccinated mice were then challenged with 30 and 100 S. japonicum cercariae, respectively. Forty-five days later, all mice were sacrificed and examined for adult worm burden, liver and stool egg count. RESULTS: All groups of mice immunized with 4 preparations of T. spiralis larvae antigen without adjuvant showed significant protection against S. japonicum. Among these antigen preparations, the soluble antigen (TsLSA) presented highest protection with reductions in worm burden and liver and stool egg counts of 21.3%, 48.0% and 58.5%, respectively. When mice were immunized with TsLSA plus Freunds complete adjuvant (FCA) or with double-dose of the antigen, the worm reduction rate was increased to 29.3% and 39.6%, respectively. CONCLUSION: Different preparations of T. spiralis muscle larva antigen could induce protection against S. japonicum in mice.

Animals↗

PubMed1998

[Study on the chemical components of Rabdosia excisa].

Four kinds of components were extracted and separated from the stems and leaves of Rabdosia excisa. They had been identified as Kamebakaurin, Ursolic acid, Daucosterol and Liquiritin respectively by physical and chemical methods, as well as spectrum data. It was first time that Liquiritin was obtained from the Robdosia family, and its 13C-NMR data of Liquiritin had not been reported before.

Chromatography, Thin Layer↗

PubMed1997

Vascular endothelial growth factor expression in choroidal neovascularization in rats.

BACKGROUND: The pathogenesis of choroidal neovascularization is largely unknown. We investigated vascular endothelial growth factor (VEGF) expression in laser-induced choroidal neovascularization (CNV) in rats. METHODS: Intense krypton laser photocoagulation was applied to the posterior poles of the eyes of pigmented rats to induce CNV, which was confirmed by fluorescein angiography and histopathology. The eyeballs were enucleated 1, 3, 7, 14 and 28 days after laser photocoagulation. Cryostat sections were prepared for immunofluorescence staining using anti-VEGF and macrophage marker (ED1) antibodies. The posterior segments of eyeballs pooled from photocoagulated and control rats were submitted for immunoprecipitation and immunoblotting by the anti-VEGF antibody, and reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of VEGF mRNA. RESULTS: Very weak immunoreactivity for anti-VEGF antibody was found in the ganglion cell layer, inner nuclear layer, and retinal pigment epithelium (RPE) in the normal retina. In the development of CNV, strong positive staining for anti-VEGF antibody was found in photocoagulated areas in the subretinal space and choroid. Double immunofluorescence staining showed that many cells in lasered lesions were positive both for anti-VEGF and macrophage marker ED1 antibody staining in the early stage of this model. Immunoblots showed a positive band for the VEGF molecule in treated but not control animals. RT-PCR results demonstrated upregulation of VEGF transcripts in the CNV model compared with normal animals. CONCLUSIONS: Our findings showed the upregulation of VEGF expression in experimentally induced CNV, where it may be involved in promoting choroidal angiogenesis. Macrophages may be one of the main sources of VEGF in the early stage of the disease.

Animals↗

PubMed1997

Transformation and tumorigenic properties of a mutant polyomavirus containing a middle T antigen defective in Shc binding.

Polyomavirus middle T antigen is phosphorylated on several tyrosine residues which act as binding sites for cellular proteins, including phosphatidylinositol 3-kinase, Shc, and phospholipase C-gamma. In this report we describe the transforming properties and tumor-inducing ability of a polyomavirus that contains a single-site mutation in middle T antigen which changes a tyrosine residue at amino acid position 250 to serine. This mutation disrupts the association of middle T with the transforming protein Shc. The mutant virus is weakly transforming, inducing foci which are smaller and of different morphology than those of the wild type. Although the virus induced tumors in close to 100% of inoculated mice, the spectrum of tumors and their morphology were altered compared to those of wild-type virus. The mutant virus induced a reduced frequency of kidney and thymic tumors. Both the mammary gland and the thymic tumors that were induced were histologically distinct from those induced by wild-type polyomavirus. These results demonstrate that the signal transduction pathway that is deregulated by the middle T-Shc association is important for full transformation of cells in culture and for tumor induction in some target tissues in the mouse-polyomavirus system.

3T3 Cells↗

PubMed1997

[Cross reaction of Trichinella spiralis larva antigens with sera of schistosomiasis japonica].

Cross reactions of T. spiralis muscular larva antigens (TsMLA) against several sera from patients with other parasitic diseases by ELIB (enzyme-linked immunoblotting technique) were studied. The proteins of 31-100 KDa were recognized by sera of two cases of acute schistosomiasis, while proteins of 44/45, 51/53, 62/64 and 100 KDa were recognized by sera of 11 cases of chronic schistosomiasis. The proteins of 60 KDa showed varied cross reactions against sera of five kinds of patients with other parasitic diseases (filariasis, hookworm diseases, paragonimiasis, ascariasis and clonorchiasis). Only the proteins of 45 KDa were recognized by six of fifteen cases of normal human sera. All of > 29 KDa proteins were recognized by sera of rabbit infected by T. spiralis. It is suggested that there were many antigens in Trichinellen muscular larva which shared in common with several other parasites. The cross reactions of TsMLA against Schistosoma japonicum may be differentiated on the positive reaction bands of 44/45, 51/53, 62/64 and 100 KDa proteins which was specific to the chronic schistosomiasis using the TsMLA by means of ELIB.

Animals↗

PubMed1997

[Identification of antigens in circulating immune complexes of schistosomiasis japonica].

In order to identify antigens in circulating immune complexes (CIC) of Schistosoma japonicum, the antiserum against CIC was first successfully prepared by immunization of New Zealand rabbit with CIC isolated from schistosome-infected rabbit sera. The antigens in CIC were identified and analyzed by EITB (enzyme-linked immunoelectro-transfer blot) techniques, using the prepared antiserum against CIC, adult worm antigens (AWA), soluble egg antigens (SEA) and adult excretory antigens (ESA). The results showed that the antiserum against CIC had recognized the AWA bands of 155, 90, 70, 31/32, 20.5, 14 and 8 KD; the SEA bands of 90, 66, 46, 34.5 and 27 KD and the ESA bands of 155, 92, 87.5, 70, 60, 57.5, 50, 46, 36, 31/32, 24, 18.5, 12 and 8 KD. These findings indicate that the antigens in CIC were derived from both schistosome adult worms and eggs. In addition, the localization of the antiserum against CIC targeted antigens in adult worms was also carried out by IFAT (indirect flourescent antibody test). It is suggested that the antigens in CIC were presented mainly in the tegument and the gut of the parasite.

Animals↗

PubMed1997

[Detection of different class (subclass) antibodies in sera of patients with schistosomiasis japonica for diagnosis and efficiency evaluation].

The subclass antibodies against IgG1, IgG3 and IgG4 in sera of the patients with chronic Schistosomiasis japonica were detected before treatment, and after treatment--6 and 12 months respectively, using Biotin-Avidin-ELISA (BA-ELISA) established by purified 31/32 KD antigen from the adult worms. At the same time IgG1 and IgM were examined by the standard ELISA. False positive reaction with normal control and cross reaction with other parasitic diseases have not been observed. The IgG1 and IgG3 subclasses showed high sensitivity and specificity and reduced quickly 6 months after treatment. These results indicate that the level of specific IgG1 and IgG4 to the 31/32 KD adult worm protein has high value for diagnosis of Schistosomiasis japonica and evaluation of the curative efficiency of the disease.

Animals↗

PubMed1997

[Analysis and prevention of road traffic fatalities in Sichuan Province].

This is an epidemiological survey of the fatalities from road traffic accidents in Sichuan. All fatal accidents that occurred in Sichuan from January 1994 to December 1994 were analysed. The mortalities per million kilometers of vehicle travel, per 100,000 registered motor vehicles and per 100,000 resident population were 4.35, 42.41 and 3.92 respectively. These figures were compared with international death rates and those reported by other countries. The results showed that Sichuan had higher mortalities per million kilometers of vehicle travel and per 100,000 registered vehicles but lower mortality per 100,000 resident population, compared with some industrialized and rich develeping countries. The majority of the victims were males aged 21 to 40. Road traffic fatalities constituted the leading cause of all accident deaths. The cost of road accidents in Sichuan was estimated to be sixty million Yuan. Further strategies and methods to minimize the rate of such accidents have been suggested.

Accidents, Traffic↗

PubMed1997

[A newly developed equipment for cleaning of sample tube used in nuclear magnetic resonance experiment].

Cleaning sample tubes used in nuclear magnetic resonance experiment is a time consuming work. We developed a new type of equipment based on fluidics for cleaning those sample tubes and successfully solved the problem. For several years of application, the developed equipment proved to be time saving and very effective. It is simple in design and easy to make up, and it can wash whatever glassware that is narrow in diameter and long in length.

Magnetic Resonance Spectroscopy↗

PubMed1996

Immunolocalization of basic fibroblast growth factor during wound repair in rat retina after laser photocoagulation.

BACKGROUND: Basic fibroblast growth factor (bFGF) stimulates the mitogenesis of various cells and plays a key role in wound repair. We studied the immunohistochemical localization of bFGF during wound repair in the rat retina after laser photocoagulation. METHODS: Krypton laser photocoagulation was performed on the eyes of pigmented rats. The eyes were enucleated on days 1, 3, 7, 14 and 28 after the photocoagulation, and the immunohistochemical localization of bFGF was assessed. Two different monoclonal antibodies and one polyclonal antibody against bFGF as first antibodies were used. RESULTS: Marked immunoreactivity for bFGF was found in the ganglion cell layer, and weak immunoreactivity for bFGF was found in the retinal pigment epithelial (RPE) cells of the normal adult rat retina. On day 3 after laser photocoagulation, the nuclei and cytoplasm of proliferating RPE cells at the center of the photocoagulated lesion showed intense bFGF immunoreactivity. The nuclei of RPE cells around the lesion showed intense bFGF immunoreactivity. Macrophages that migrated into the lesion showed positive staining for bFGF. These immunoreactivity decreased with time. Controls (0.05 M Tris-HCl buffer, normal serum, or these same antibodies preabsorbed with bFGF) did not show positive staining. CONCLUSION: The finding of an elevated expression of bFGF immunoreactivity in the photocoagulated lesion suggests that bFGF may play a role in wound repair in the rat retina after laser photocoagulation.

Animals↗

PubMed1996

Expression of basic fibroblast growth factor mRNA in developing choroidal neovascularization.

PURPOSE: Basic fibroblast growth factor (bFGF) is an angiogenic peptide that may be important in the pathogenesis of choroidal neovascularization. We attempted to determine the transcription of the bFGF gene during the development of experimentally induced choroidal neovascularization. METHODS: Rat bFGF cDNA was inserted in the pBluescript to prepare antisense and sense riboprobes. Multiple krypton laser burns were applied to the posterior poles of the eyes of pigmented rats according to a protocol described for producing subretinal neovascularization in these animals. At intervals of up to 4 weeks after photocoagulation, the eyes were removed and cut into thin sections. The sections were subjected to histopathological analysis, cell proliferation study, or in situ hybridization with digoxigenin (DIG)-labeled single-strand riboprobes synthesized from rat bFGF cDNA. RESULTS: In normal adult rat retinas, bFGF mRNA expression was mainly observed in the ganglion cell layer and the inner nuclear layer. After laser photocoagulation, proliferation of RPE cells, fibroblast-like cells and cells in the choroid in the lesions were observed. Expression of bFGF mRNA was observed in the lesions 3 days to 2 weeks after laser treatment. Signals of bFGF mRNA were detected in the proliferating RPE-like cells, choroidal vascular endothelial cells and fibroblast-like cells, all of which are essential for neovascularization. However, bFGF mRNA expression was no longer detectable in these cells 4 weeks after photocoagulation. CONCLUSIONS: Our findings indicate that bFGF is normally transcribed in ganglion cells and the inner nuclear cell layer. During the neovascularization that followed laser photocoagulation, bFGF mRNA expression was detected within the laser lesions. It is thus probable that bFGF acts as a mediator in the neovascularization process.

Animals↗

PubMed1996

Immunohistochemical proof of origin of macrophages in laser photocoagulation lesion in the retina.

The origin of the macrophages which appear in the subretinal space after laser photocoagulation on the rat retina was investigated using immunohistochemistry. The majority of macrophages located in laser lesions were found to be positive to staining for the specific rat monocyte/macrophage marker (ED1). The number of macrophages and activated macrophages were abundant after intense laser photocoagulation in which choroidal neovascularization was induced. After the retinal pigment epithelium (RPE) was damaged by intravenous administration of sodium iodate, the number of migrating macrophages in the subretinal space of lasered areas significantly decreased to a level comparable to the level found in control animals. These results suggested that the macrophages were derived mainly from monocytes in the blood, not from RPE cells, and that they may play a role in the development of the choroidal neovascularization.

Animals↗

PubMed1996

[Isolation and structure flucidation of alkaloids from the bulb of Fritillaria Wabuensis S.Y. Tang et S.C. Yueh].

Eight alkaloids were isolated from the bulb of Fritillaria Wabuensis S.Y. Tang et S.C. Yueh the best "Chuan Bei" cultivated in Sichuan province, which is efficacious against cough. Five of them are known, identified as imperialine (I), peimisine (II), ebeinone (III), isoverticine (IV), and imperialine-beta-N-oxide (V). All the signals for both 1H and 12C-NMR spectra of base (V) were assigned by 2D NMR experiments, and an X-ray structural data of alkaloid (V) was obtained for the first time.

Alkaloids↗

PubMed1996

[Subcellular location of blood group substances ABH using transmission electron microscopical immunocytochemistry technique].

The subcellular location of blood group substances ABH was studied by using transmission electron microscopical immunocytochemistry. The cells were the epithelial cells of both mucous membranes and glands of normal human stomach, duodenum and transverse colon. Both cellular ultrastructure and antigens should be well preserved in transmission electron microscopical immunocytochemistry. In this paper, various fixatives, embedding media and immunostaining methods were investigated and compared. The results indicate that the solution containing 2% paraformaldehyde and 0.2% glutaraldehyde (2PG) is the best fixative and Epon 812 medium is the best embedding medium for preserving ABH antigens and protecting cellular ultrastructure. Post-embedding immunogold staining technique is superior to pre-embedding immunoperoxidase staining.

ABO Blood-Group System↗