Biomedical subjects

R Sun

Publications and source records attributed to R Sun.

At least 127 records · Page 7Linked to original sources

PubMed1997

[Clinical study of the relationship between the lateral recesses and the nerve roots].

To explicate the relationship and the clinical signification between the normal or narrow lateral recesses and the nerve roots, we measured the diameter of the entrans zone of the lateral recess, the interval between the upper articular processes and the interval between the nerve root and ab line on 50 normal cases, 43 narrow cases and 32 stenosis cases with VIDS image analysis system. The results showed that the nerve root was in the center side of the ab line in the normal station, with the degrees of the degeneration and cohesion ncreasing, the nerve root was in the lateral recess side of the ab line, and was compressed by the lateral recess. The authors considered that the real clinical signification of the entrance zone of the lateral recess was danger to the nerve root, but the deciding factors were the degrees of the degeneration and cohesion of the upper articular processes. The pathological conditions that resulted in the stenosis of the lateral recess and dangered the nerve root such as disc, flavum ligament and posterior port of the fibra ring were discussed in the article.

Adult↗

PubMed1997

[Changes of PDGF-alpha and beta receptor gene expression in hypoxic rat pulmonary vessels].

OBJECTIVE: To reveal the role of platelet-derived growth factor-alpha and beta receptor in hypoxic pulmonary vascular remodeling. We investigated the changes of PDGF-alpha and beta receptor gene expression under hypoxic condition. METHODS: Hypoxic pulmonary hypertension rats model was reproduced by normobaric hypoxia. Changes of pulmonary PDGF-alpha and beta mRNA were examined by in situ hybridization. RESULTS: The PDGF-alpha receptor mRNA of the hypoxia group (3 days) declined to 86% compared with that of the control group, and shooting up to 217% of control at day 7, then sustained at 224% until day 14. (all P < 0.001). PDGF-beta receptor mRNA markedly increased at day 3 after hypoxia and maintained this increasing tendency consistently. Its top was 164% at day 14 (P < 0.001). The growth inhibitor, heparin had alleviated the increases of both rat pulmonary arterial pressure and PDGF receptor gene expression. CONCLUSION: Hypoxia led to the increase of PDGF-alpha and beta receptor gene expression in pulmonary vascular endothelial and smooth muscle cells, and might be involved in hypoxic pulmonary vascular remodeling.

Animals↗

PubMed1997

[SERS and electrochemistry studies on the inhibition of thiourea and phenyl-thiourea on iron].

An iron electrode was obtained by depositing a thin layer of iron on active silver electrode with overpotential deposition method. The E - I curve and SERS spectra of thiourea (TU) and phenyl-thiourea (PTU) adsorbed on the iron electrode surface were studied by means of electrochemistry and SERS spectroscopy. The results showed that both TU and PTU can be adsorbed on the iron electrode surface and the inhibition of PTU is better than TU in 0.1mol/L KCl solution. The adsorption mode of TU and PTU is similar in the interaction of S atom and iron surface. The cause of better inhibition effect of PTU lies in that the PTU can be more easily adsorbed on iron electrode because of more negative charge in its S atom and benzene ring in PTU is arranged away from the iron surface to form a rather compact adsorption layer due to steric hindrance.

English Abstract↗

PubMed1997

Excimer laser photorefractive keratectomy for residual myopia after radial keratotomy.

OBJECTIVE: To evaluate the surgical outcome of excimer laser photorefractive keratectomy (PRK) for undercorrected myopia after radial keratotomy (RK). DESIGN: Case series. SETTING: Gimbel Eye Centre, Calgary. PATIENTS: Thirty-one patients (37 eyes) who underwent excimer laser PRK for residual myopia after RK and were followed for at least 12 months. OUTCOME MEASURES: Spherical equivalent refraction, uncorrected and best corrected Snellen visual acuity, attempted and achieved correction, and corneal haze. RESULTS: The mean refraction before PRK was -3.11 (standard deviation [SD] 1.48) dioptres and 12 months after PRK, -1.18 D (SD 1.48 D) (p < 0.0001). Twelve months after PRK 24 eyes (64.9%) had an uncorrected visual acuity of 20/40 or better. Five eyes lost one line of best corrected acuity, and one eye lost more than two lines. At 12 months 28 eyes (75.7%) had no corneal haze or trace haze, 8 (21.6%) had mild haze, and 1 (2.7%) had marked haze. CONCLUSIONS: Our results indicate that excimer laser PRK has the potential to manage undercorrection of myopia after RK. The issues of refractive predictability, loss of best corrected visual acuity and corneal haze require further study.

Adult↗

PubMed1997

Management of zonular dialysis in phacoemulsification and IOL implantation using the capsular tension ring.

BACKGROUND AND OBJECTIVES: Cataract surgery with zonular dialysis remains a challenge for surgeons performing phacoemulsification and posterior chamber intraocular lens implantation. In this article, the authors report the results of cataract surgery with zonular dialysis that was managed with the capsular tension ring. PATIENTS AND METHODS: Of the 14 cataract surgery cases with loose or broken zonules managed with capsular tension rings that were retrospectively reviewed, 5 selected cases are presented in this article. RESULTS: The authors found that the capsular tension ring helps to avoid capsular collapse and vitreous presentation during surgery and maintains the circular contour of the capsular bag, allowing the intraocular lens to easily be placed into the bag. There was no observable decentration of the intraocular lens after surgery. CONCLUSION: The capsular tension ring may provide an alternative means to manage zonular dialysis during phacoemulsification and posterior chamber intraocular lens implantation.

Aged↗

PubMed1997

[Study on relationship between personality traits and social life abilities in children].

Author surveyed 330 pupils and their parents by using Eysenck Pensonality Questionnaire (E. P. Q) and Infants-Junior Middle School Students' Social-Life Abilities Scale, to explore the relationship between personality and Social-life abilities in children. Result show there was no relationship between social-Life abilities and degrees of psychoticism, neuroticism and lie in children. It was closely related between social-life abilities and personality of children. The children with low social-life abilities are mostly introverted. The children with high social-life abilities, especially in communication, are mostly extroverted. Children over 10 year-old with high locomotion are mostly extroverted (P < 0.05). As results of the study, parents and pediatric nurses should assist the personality of children to be developed toward extroversion tendencies.

Child↗

PubMed1996

Differential production of interleukin-6 and its close relation to liver metastasis in clones from murine P815 mastocytoma.

Interleukin-6 (IL-6)-producing abilities of plastic-adherent and plastic-non-adherent P815 clones were investigated in connection with the liver metastasis. Most adherent clones produced IL-6 at high level (over 10 ng/10(5) cells per 48 h), and they coincided with highly liver-metastatic clones. The remaining adherent and all the non-adherent clones tested produced IL-6 at low level (under 1.5 ng/10(5) cells), and they coincided with the low or non-liver-metastatic clones. The IL-6 production was greatly enhanced by IL-1 alpha, but not by IL-6, tumor necrosis factor-alpha or interferon-gamma.

Animals↗

PubMed1996

Polyadenylylated nuclear RNA encoded by Kaposi sarcoma-associated herpesvirus.

A newly recognized gamma herpesvirus known as Kaposi sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is present in Kaposi sarcomas and body-cavity-based lymphomas. Here we identify a novel abundant 1.2-kb RNA, polyadenylated nuclear RNA (PAN RNA), encoded by the virus. The majority of cDNAs produced from poly(A)-selected RNA isolated from a human body cavity lymphoma cell line 48 hr after butyrate induction of KSHV lytic replication represented PAN RNA. Within PAN RNA were two 9 and 16 nt stretches with 89% and 94% identity to U1 RNA. A third stretch of 14 nt was 93% complementary to U1. The 5' upstream region of PAN RNA contained both proximal and distal sequence elements characteristic of regulatory regions of U snRNAs, whereas the 3' end was polyadenylylated. PAN RNA was transcribed by RNA polymerase II, lacked a trimethylguanosine cap, and did not associate with polyribosomes. PAN RNA formed a speckled pattern in the nucleus typical of U snRNAs and colocalized with Sm protein. Therefore, PAN represents a new type of RNA, possessing features of both U snRNA and mRNA.

Base Sequence↗

PubMed1996

In vivo CTL immunity can be elicited by in vitro reconstituted MHC/peptide complex.

The use of peptides as a vaccine is a potentially powerful immunization strategy. We explored the possibility of inducing an efficient cytotoxic T lymphocyte (CTL) mediated immune response in mice, using in vitro reconstituted major histocompatibility complex (MHC) class I/peptide complexes as the immunogen. Recombinant derived H-2Kb and beta 2-microglobulin (beta 2m) were properly folded into an MHC class I complex using the vesicular stomatitis virus (VSV)-8mer from the natural nucleocapsid proteinN52-59 (RGYVYQGL), an immunodominant Kb epitope in C57BL/6 (B6) mice. After immunizing mice with the H-2Kb class I/VSV peptide complex and a subsequent in vitro stimulation with the VSV peptide alone, a specific CTL response was demonstrated. The method was also applicable to other peptides, for example, the Sendai virus (SV) peptideN324-332 (FAPGNYPAL). The CTL response was mediated by CD3+/CD8+ T cells and was shown to be allele specific, as only peptide loaded target cells expressing the H-2Kb allele could be recognized. It is of interest that extremely small amounts of injected MHC class I/peptide complex (i.e. 500 pg) could generate a measurable CTL response. The MHC class I/peptide complex had to be intact and properly folded to elicit an immune response, suggesting that the complex protected the peptide for internalization by antigen presenting cells (APCs) or for delivering to the proper site for peptide exchange on the cell surface of APCs. The described immunizing method can be routinely used to prime a CTL response by employing in vitro folded MHC class I/peptide complexes, without the use of adjuvants. It appears to be efficient, sensitive and specific. By using the recombinant protein system, unlimited amounts of MHC class I/peptide complex can be produced for immunization. Moreover, this protocol permits different in vitro combinations of allelic MHC class I molecules and peptide variants.

Amino Acid Sequence↗

PubMed1996

Antibodies to butyrate-inducible antigens of Kaposi's sarcoma-associated herpesvirus in patients with HIV-1 infection.

BACKGROUND: The recent identification in patients with Kaposi's sarcoma of DNA sequences with homology to gammaherpesviruses has led to the hypothesis that a newly identified virus, Kaposi's sarcoma-associated herpeslike virus (KSHV), has a role in the pathogenesis of Kaposi's sarcoma. We developed serologic markers for KSHV infection. METHODS: KSHV antigens were prepared from a cell line (BC-1) that contains the genomes of both KSHV and the Epstein-Barr virus (EBV). We used immunoblot and immunofluorescence assays to examine serum samples from 102 patients with human immunodeficiency virus type 1 (HIV-1) infection for antibodies to KSHV-associated proteins and to distinguish these antibodies from antibodies to EBV antigens. A positive serologic response was defined by the recognition of an antigenic polypeptide, p40, in n-butyrate-treated BC-1 cells and by the absence of p40 recognition in untreated BC-1 cells or EBV-infected, KSHV-negative cells. The detection by the immunofluorescence assay of 10 to 20 times more antigen-positive cells in n-butyrate-treated BC-1 cells than in untreated cells was considered a positive response. RESULTS: Antibodies to the p40 antigen expressed by chemically treated BC-1 cells were identified in 32 of 48 HIV-1-infected patients with Kaposi's sarcoma (67 percent), as compared with only 7 of 54 HIV-1-infected patients without Kaposi's sarcoma (13 percent). These results were confirmed by an immunofluorescence assay. The positive predictive value of the serologic tests for Kaposi's sarcoma was 82 percent, and the negative predictive value 75 percent. CONCLUSIONS: The presence of antibodies to a KSHV antigenic peptide correlates with the presence of Kaposi's sarcoma in a high-risk population and provides further evidence of an etiologic role for KSHV.

Antibodies, Viral↗

PubMed1996

Effect of pharmacological dilation and constriction of pupil on corneal topography.

A prospective study was undertaken to investigate the effect of pharmacological pupillary dilation and constriction on corneal topography. Corneal topography was performed using the EyeSys system on 28 normal subjects before and after pupil dilation, constriction, and then with the pupil intact (no medication). Our results show that both flattening and steepening of the corneal curvature were found in all three examination periods. The numbers of corneas with flattening and steepening in each examination period were compared and found not to be statistically different. Mean change of corneal flattening was compared with mean change of corneal steepening in each examination period and again no significant difference was found. These results indicate that the slight changes in corneal power and radius following pharmacological pupillary dilation or constriction may be due to either the inability to repeat by the subjects, or error by observers or instrument.

Adult↗

PubMed1996

Two 21-kilodalton components of the Epstein-Barr virus capsid antigen complex and their relationship to ZEBRA-associated protein p21 (ZAP21).

The viral capsid antigen complex of Epstein-Barr virus (EBV), an important serodiagnostic marker of infection with the virus, consists of at least four components, with molecular masses of 150, 110, 40, and 21 kDa. Here we show that the 21-kDa component of the viral capsid antigen consists of products of two EBV genes, BFRF3 and BLRF2. Both products were expressed from late transcripts, were recognized by human antisera, and were present in virions. The BFRF3 product, but not that of BLRF2, fulfilled the definition of ZEBRA-associated protein p21 (ZAP21). In cells in which EBV was lytically replicating, BFRF3 protein was coimmunoprecipitated together with ZEBRA by a rabbit antiserum directed against amino acids 197 to 245 of BZLF1. In EBV-negative cells cotransfected with BZLF1 and BFRF3 expression vectors, BFRF3 was also coimmunoprecipitated with this antiserum. Although this antiserum could not detect BFRF3 on an immunoblot, it was able to immunoprecipitate BFRF3 in the absence of ZEBRA expression. The rabbit antiserum to amino acids 197 to 245 of BZLF1 was found to detect the same epitope at the carboxy end of BFRF3 as was recognized by rabbit antiserum to BFRF3 itself. Thus, coimmunoprecipitation of BFRF3 p21 with ZEBRA appeared to be due to cross-reactivity of the immunoprecipitating antiserum rather than to direct association of ZEBRA and BFRF3 p21.

Animals↗

PubMed1996

Hypoxic-ischemic brain injury induces an acute microglial reaction in perinatal rats.

Activated microglia may contribute to the progression of neuronal injury after a wide range of CNS insults. In this study, we used two complementary methods to evaluate acute changes in the morphology and regional distribution of microglia induced by a focal hypoxic-ischemic insult in 7-d-old (P7) rats. To elicit injury, P7 rats underwent right carotid ligation followed by 3 h of 8% O2 exposure; rats were killed 10 min to 5 d later (n > or = 3/group). A histochemical assay using Griffonia simplicifolia B4-isolectin enabled detection of both resting and activated microglia in tissue sections; vascular cells were also reactive. Activated microglia were also identified immunocytochemically using a macrophage-specific MAb, ED-1. In normal P7-12 brain, lectin, and ED-1 immunoreactive-activated microglia were concentrated in white matter; lectin-positive resting, ramified microglia were also detected throughout the gray and white matter. Subtle morphologic evidence of microglial activation was noted 10 min posthypoxia-ischemia in the lesioned right cerebral hemisphere; activated microglia began to accumulate within the next 4 h. Accumulation of lectin-positive activated microglia peaked at 2-4 d posthypoxia-ischemia. ED-1 immunoreactive-microglia were first noted 4 h after hypoxic-ischemic injury in the lesioned right hemisphere, and there was a corresponding increase in accumulation over the first 48 h posthypoxia-ischemia. In the left hemisphere, contralateral to the ligation, no increase in activated microglia were detected with either method. In brain sections where no neuronal injury was evident, activated microglia did not accumulate. These data demonstrate that perinatal hypoxic-ischemic brain injury induced rapid accumulation of activated microglia in hypoxic-ischemic forebrain.

Animals↗

PubMed1996

The relationship between adherence and liver metastatic ability in murine mastocytoma cell line.

P815 murine mastocytoma cells were separated to plastic-adherent and -nonadherent cell populations by repetitive in vitro selections. Their abilities of experimental and spontaneous metastases were investigated in the syngeneic DBA/2 mice. While the plastic-adherent populations were found to be liver-metastatic, the plastic-nonadherent populations were liver-nonmetastatic. The inability of plastic-nonadherent P815 cells to metastasize to the liver did not mean that these cells were not tumorigeneic because they could metastasize to tissues and/or organs other than the liver. Hence it could be looked as inability for liver specific metastasis resulted from, or related to, the loss of plastic adhesiveness. By limiting dilution of plastic-adherent and -nonadherent P815 cells, two series of well comparable P815 clones were established: (1) plastic-adherent, liver-metastatic clone and (2) plastic-nonadherent, liver-nonmetastatic one. Since these two series of P815 clone are originated from a common parent line, they might be valuable in the study of the molecular mechanisms of liver specific metastasis and of the relations between liver metastasis and cell adhesiveness.

Animals↗

PubMed1996

Anterior chamber fluid cultures following phacoemulsification and posterior chamber lens implantation.

BACKGROUND AND OBJECTIVE: A randomized, prospective study was undertaken to evaluate the incidence of positive cultures in the anterior chamber following cataract surgery when using intracameral gentamicin compared with no antibiotic. PATIENTS AND METHODS: A total of 97 patients were enrolled-- 48 receiving gentamicin in the irrigating solution and 49 receiving no intracameral antibiotics (control group). Each cataract extraction was accomplished by phacoemulsification followed by intraocular lens implantation. At the end of surgery, o.1 ml of anterior chamber fluid from each case was collected and cultured. RESULTS: All cultures were negative in the group receiving gentamicin. However, one positive culture occurred in the control group. There was no significant difference in the positive culture rate between the two groups (P = .52). CONCLUSION: This study suggests that cataract extraction with phacoemulsification and intraocular lens implantation has greatly reduced the incidence of bacterial contamination of anterior chamber fluid, with or without the use of intracameral antibiotic.

Anterior Chamber↗

PubMed1996

Effects of anti-intercellular adhesion molecule-1 and anti-lymphocyte-function-associated antigen-1 monoclonal antibodies on the metastasis of murine tumors.

Anti-intercellular adhesion molecule-1 (anti-ICAM-1) and anti-lymphocyte-function-associated antigen-1 (anti-LFA-1) monoclonal antibodies (mAbs) were injected into mice and their effects on tumor metastasis were investigated using two murine models. Depending on the dose, the anti-ICAM-1 mAb (KAT-1) expressed both inhibitory and promoting effects on liver metastases of ICAM-1 + LFA-1 + P815 mastocytoma cells, whereas it enhanced lung metastases of the ICAM-1-LFA-1-Meth-A fibrosarcoma cells at any doses. In contrast, anti-LFA-1 mAb (KBA) showed promoting effects only on the metastases of both tumor lines. Treatment of mice with either mAb enhanced metastases of P815 mastocytoma cells in the spleen.

Animals↗

PubMed1996

Effect of commercial dilating agents on laser flare-cell measurements.

OBJECTIVE: To compare the effect of tropicamide alone and tropicamide-phenylephrine on anterior chamber flare and cell measurements obtained with a laser flare-cell meter. DESIGN: Prospective study. SETTING: Gimbel Eye Centre, Calgary. SUBJECTS: Twenty white subjects (10 with blue irides and 10 with brown irides) aged 24 to 45 (mean 30.2) years without any known systemic or ocular disease. INTERVENTIONS: Laser flare-cell measurements were obtained 30 minutes after pupillary dilation with 1% tropicamide in one eye and a combination drop of 0.8% tropicamide and 5% phenylephrine in the other eye. The average of five readings was taken for each eye. OUTCOME MEASURES: Flare and cell measurements. RESULTS: There was no statistically significant difference in flare photon count or cell count between the eyes dilated with tropicamide and those dilated with tropicamide-phenylephrine. In addition, iris colour was not found to have a significant effect on flare and cell measurements. CONCLUSIONS: Our results suggest that pupillary dilation for laser flare-cell measurements can be done with either mydriatic agent in healthy white subjects of any eye colour without significant effects on the measurements. Further study is needed to determine whether the same is true in older subjects.

Administration, Topical↗

PubMed1996

[Three-dimensional recons-truction of lumbar-sacral canal and its contents: experimental study].

In order to suit the needs of studies in spinal column surgery on three-dimensional spatial structure and morphology of lumbar-sacral canal and the nervous tissue within it, an experimental model was applied by the authors using lumbosacral specimens from two fresh young adult cadavers. Successive 2mm thick CTM screening was carried out from L3 to S2 vertebral bodies with an interval of 1mm. The serial two-dimensional CT photographical pictures so obtained were inputted into a computer and the three-dimensional images were reconstructed through a VIDAS image analysis system. The experimental results indicated that the three-dimensional images of reconstructed vertebral canal and the nervous tissue within it were lifelike. These images could not only reveal their three-dimensional structure and morphology, but also be cut and composed together at any direction and section by turning and transpositioning along X, Y and Z axes. The authors hold that the visual effect expressed by three-dimensional images reconstructed from two-dimensional pictures can play important role in stereomorphologic, biomechanical, and other studies in fields of anatomy, image analysis, and clinical medicine.

Adult↗