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Biomedical subjects

R Sun

Publications and source records attributed to R Sun.

At least 163 records · Page 9Linked to original sources
PubMed1995

[The study of growth factors in human colostrum].

OBJECTIVE: To characterize and identify the growth factors in human colostrum and to evaluate the importance of breast-feeding. METHODS: The activity of growth factors in human colostrum was determined by technique of 3H-TdR incorporation into cultured NIH-3T3 cells. The acid growth factor (CAGF) and basic growth factor (CBGF) were purified from human colostrum by a sequence of chromatography. The study of stability and SDS-PAGE was applied to identify the CAGF and CBGF. RESULTS: 0.5% (v/v) of human colostrum and 3.0% (v/v) of bovine serum had the same activity in stimulating DNA synthesis. The specific activity of human colostrum in stimulating DNA synthesis was 20 times greater than that of bovine serum. The activity of growth factors in human colostrum was higher than that in human milk or bovine colostrum, and only human colostrum contained two different kinds of growth factors--CAGF and CBGF. CONCLUSIONS: Human colostrum contains two kinds of growth factors. CAGF is epidermal growth factor like (EGF-like) growth factor and the CBGF is platelet differentiation growth factor like (PDGF-like) growth factor. The effects of human colostrum on promoting baby growth and development is stronger than that of human milk and bovine colostrum.

3T3 Cells↗
PubMed1994

Autoantigenic proteins that bind recombinogenic sequences in Epstein-Barr virus and cellular DNA.

We have identified conserved autoantigenic cellular proteins that bind to G-rich sequence motifs in recombinogenic regions of Epstein-Barr virus (EBV) DNA. This binding activity, called TRBP, recognizes the EBV terminal repeats, a locus responsible for interconversion of linear and circular EBV DNA. We found that TRBP also binds to EBV DNA sequences involved in deletion of EBNA2, a gene product required for immortalization. We show that TRBP binds sequences present in repetitive cellular DNA, such as variable-number tandem repeats (VNTR) and immunoglobulin heavy-chain class switch regions. We propose that EBV utilizes cellular DNA recombination systems to mediate several types of viral genome alterations. These findings may lead to an understanding of the mechanism of rearrangements of EBV DNA that are a central feature of the biology of the virus.

Animals↗
PubMed1994

Role of collagen metabolism changes in the pathogenesis of pulmonary hypertension in rats and its reversibility.

Pulmonary arterial pressure (PAP) was increased obviously in rats after 3 days of normobaric hypoxic exposure and reached a maximum at 14 days of hypoxia. It remained at the same level during prolonged hypoxic exposure of up to 21 days. Right ventricular weight (RV/LV+S) and hydroxyproline (HP) content in the pulmonary artery began to increase at day 7. HP content had increased much faster than the relative rate of increase of PAP after 14 days, but HP content in the thoracic aorta showed no change. The relative proportion of type I to III collagen increased significantly, and compliance of the pulmonary vessels obviously decreased. All parameters returned to the normal range within 14 days after recovery from hypoxia, except for HP content as expressed per vessel. 764-3 treatment obviously attenuated most of the changes caused by hypoxia, though it had no effect on compliance of the pulmonary vessels. It is suggested that collagen, especially type I collagen, accumulation may play an important role in maintaining pulmonary hypertension. 764-3 has certain protective effects and may be useful in the treatment of early chronic obstructive pulmonary disease.

Animals↗
PubMed1994

[Clinical analysis of ovarian and cervical malignant lymphoma].

From Oct. 1980 to Oct. 1990, 456 cases with ovarian malignant tumor and 1,281 cases with cervical malignant tumor were admitted in our hospital. Among them, 7 were ovarian lymphoma and 3 were cervical lymphoma, accounting for 1.5% and 0.23% of ovarian and cervical malignant tumors respectively. According to the standard set up by Foxs, 5 were primary and 5 were metastatic in 10 lymphoma cases. Ovarian and cervical lymphoma were few, the primary cases were fewer. But its prognosis was better than the metastatic cases. The prognosis varied with the stages, the more advanced clinical stage, the high worse prognosis. The following condition indicates poor prognosis: rapid onset of abdominal symptoms; the presence of systemic symptoms; bone marrow infiltration; bilateral ovarian tumors; noncleaved cell pattern and cleaved-noncleaved cell mixture pattern; only treated with chemotherapy. Surgery was the first choice in the treatment of lymphoma. The typical operation on ovarian lymphoma was total hysterectomy, bilateral adnexectomy and omentectomy. The cytoreductive surgery which was used to advanced ovarian cancer was also proper for lymphoma, leaving the remained tumor 2cm in diameter, followed by introperitoneal and intravenous chemotherapy. The chemotherapy method was COP or COHP regimen. The treatment of primary cervical lymphoma was radical hysterectomy and pelvic paraaorta abdominal lymphodenectomy or radiotherapy. It seems that lymphoma was highly sensitive to radiotherapy. But radiotherapy was not proper for the metastatic cases because the affected areas were large. SLDH elevated in 5 cases of the 6 cases. It suggested that SLDH can serve as relative indicator for the diagnosis and prognosis of lymphoma.

Adult↗
PubMed1993

Hemodynamic and nonhemodynamic mechanism of experimental pulmonary edema in rats and the effect of anisodamine and tetramethylpyrazine--electron microscopic observation and measurement of pulmonary arterial, pulmonary arterial wedge and systemic arterial pressure (Part 2).

The pulmonary edema (PE) induced by adrenaline (AD) administration is similar to neurogenic PE. Anisodamine (ADM, 654-2, 30 mg/kg) and tetramethylpyrazine (TMP, 120 mg/kg) have shown significant preventive effects. Electron microscopic observation was carried out to study the changes of microvascular permeability, and the dynamic change of mean pulmonary arterial pressure (PAP, 40 rats), mean pulmonary arterial wedge pressure (PAWP, 20 rats) and mean carotid arterial pressure (CAP) were also measured. The results suggested that both ADM and TMP have significant inhibitory effects on PAWP and CAP increase, as well as on the damage responsible for the increase of microvascular and alveolar permeability.

Adrenergic alpha-Agonists↗
PubMed1993

Hemodynamic and nonhemodynamic mechanisms of experimental pulmonary edema in rats and the effects of anisodamine and tetramethylpyrazine--estimation of blood gas analysis, RBC superoxide dismutase and prostaglandin E2 in plasma and bronchoalveolar lavage (Part 3).

Anisodamine (ADM, 654-2, 30 mg/kg) and tetramethylpyrazine (TMP, 120 mg/kg) have shown an apparent preventive effect on pulmonary edema (PE). In this study, the nonhemodynamic mechanism was studied: The dynamic changes of PaO2, O2Sat, PaCO2, and blood pH were measured, and RBC superoxide dismutase (SOD) and plasma and bronchoalveolar lavage (BAL) PGE2 levels were estimated. It was concluded that ADM and TMP exerted inhibitory effects on the hypoxic state. The ability of ADM and TMP to adjust RBC SOD and PGE2 levels may be one of the preventive mechanisms of the drugs.

Animals↗
PubMed1993

Effect of contact lens wear on photorefractive keratectomy.

This study compares refractive effect and epithelial healing after photorefractive keratectomy among patients who wore contact lenses before surgery versus those who wore glasses before surgery. Data were reviewed on 130 photorefractive keratectomy cases at the 1-week, 2-week, and 4- to 6-month postoperative visits. The patients were divided into three groups based on whether or not they wore contact lenses before surgery: 1) rigid gas permeable lens wearers; 2) soft lens wearers; 3) no contact lens wear. There were no significant differences in epithelial healing among the groups. Some regression of refractive effect was observed both in mean spherical equivalent and in mean keratometry in all the groups from 2 weeks to 6 months postoperatively. There was no significant difference in the regression of each group. In addition, the changes of spherical equivalent and keratometry before surgery and 4 to 6 months after surgery were compared among the groups with no significant differences. Based upon these results, we conclude that contact lens wearing does not seem to influence epithelial healing after photorefractive keratectomy surgery and also does not affect the refractive effect in the early postoperative period.

Contact Lenses, Extended-Wear↗
PubMed1993

The role of activated neutrophils and free radical in the pathogenesis of pulmonary hypertension.

In in situ perfused rat lungs, it was demonstrated that the perfusing pressure and permeability of pulmonary capillaries were obviously increased after activated neutrophils (PMNs) were added to the perfusate. The effect of free radicals generated by the xanthine-xanthine oxidase system on isolated rabbit pulmonary arterial ring tension was also observed, and the contractile response was found to be dose dependent: The smaller the vessel diameter, the higher the contractile response. Superoxide dismutase and catalase were able to obviously attenuate the contractile response. The response was endothelium independent, and was influenced neither by indomethacin (cyclooxygenase inhibitor) nor by nordihydroguaiaretic acid (lipoxygenase inhibitor), while removal of Ca from the bath solution or addition of the protein kinase C (PKC) inhibitor "H7" or an antiinflammatory drug (764-3, the effective component of Radix Salvia miltiorrhizae) could significantly inhibit the contractile response. The results suggest that activated PMNs may play an important role in the pathogenesis of pulmonary hypertension.

Animals↗
PubMed1993

Hemodynamic and nonhemodynamic mechanisms of experimental pulmonary edema in rats and the effect of anisodamine and tetramethylpyrazine. Part 1: Survival rate, pulmonary index, pathological change and pulmonary vascular permeability.

Pulmonary edema (PE) which is similar to the neurogenic type was induced by adrenaline (AD) administration (0.1 mg/kg) in rats. Acute progressive respiratory distress, cyanosis and dyspnea occurred. All the experimental animals in the PE group died within 20 min after AD injection, with a pulmonary index (PI) of 1.70 +/- 0.47 (mean +/- S) which was much higher than that in the normal group. The mortality rate was 100%. It was found that in rats with PE, a protein-rich fluid filled the alveolar and interstitial spaces, and ecchymosis occurred. The capillary permeability as estimated by Evans blue injection showed that Evans blue from extraction fluid and bronchoalveolar lavage (BAL) in the PE rats was at a much higher level than that in the normal control (NC) rats. In anisodamine (ADM, 654-2) and tetramethylpyrazine (TMP) treated rats, almost all the damage was diminished or absent, and the mortality rates were decreased from 100% to 4.4% and 20%, respectively. 654-2 and TMP could significantly inhibit the increase of pulmonary permeability.

Animals↗
PubMed1993

Postoperative astigmatism following phacoemulsification with sutured vs. unsutured wounds.

A total of 293 cases of phacoemulsification cataract surgery with a 5.0- or 6.0-mm frown incision were analysed retrospectively to compare postoperative astigmatism between cases with sutured wounds and those with unsutured wounds. Astigmatic analysis was done with a simplified method (keratometric readings with steep meridians between 46 degrees and 134 degrees were considered "with-the-rule" [WTR], and those with steep meridians less than 46 degrees and greater than 134 degrees, "against-the-rule" [ATR]). Among patients with WTR astigmatism preoperatively, the mean keratometric cylinder in the sutureless group (n = 53) was significantly lower at 1 day and at 4 to 6 months postoperatively than before surgery (p < or = 0.001); in the suture group (n = 120) the mean cylinder was significantly higher at 1 day and significantly lower at 4 to 6 months than before surgery (p < 0.05). Among patients with ATR astigmatism preoperatively, the mean keratometric cylinder in the sutureless group (n = 22) was significantly higher at 1 day than before surgery (p < 0.01); in the suture group (n = 98) the mean cylinder was significantly lower at 1 day than before surgery (p < 0.001), and the difference at 4 to 6 months almost reached statistical significance (p = 0.052). Vector analysis showed that surgically induced cylinders in the suture and sutureless groups were similar. Our findings suggest that in the short term patients with preoperative WTR astigmatism may benefit from unsutured wounds, and those with preoperative ATR astigmatism may benefit from sutured wounds if the incision is placed in the vertical meridian.

Astigmatism↗
PubMed1993

[Interleukin-6 gene expression of human fetal islets and its relation to insulin secretion].

The islet from human fetal pancreas was separated by collagenase type V (0.5 mg/ml) and cultured to observe spontaneous secretion of interleukin-6 (IL-6), its relationship to insulin secretion, regulatory effect of IL-6 on insulin secretion of islets and IL-6 gene expression of human fetal islets. IL-6 was secreted by cultured human fetal islets in vitro and paralleled to their insulin secretion. The MH60.BSF2 cell proliferated by 50 folds when cultured to the supernatant of human fetal islets. RNA dot hybridization with bioting-labelled IL-6 cDNA showed that IL-6 gene expressed on human fetal islets. IL-6 promoted the insulin secretion of islets dose-dependently. The results suggested that IL-6 may be one of the promoting or regulating factors in the insulin secretion of islets.

Cells, Cultured↗
PubMed1992

Mapping the orientation of an antigenic peptide bound in the antigen binding groove of H-2Kb using a monoclonal antibody.

The major histocompatibility complex class I molecules are receptors for intracellular peptides, both of self and non-self origin. When non-self peptides (eg., pathogen derived) are bound to the class I molecules, they form ligands for T cell receptors resulting in antigen specific lysis of the infected cells by cytotoxic T lymphocytes. Therefore, an understanding of the process of antigen recognition requires the precise definition of the structural features of the bimolecular complex formed by a single well defined antigenic peptide bound to the class I molecule. A strategy using antibodies was developed to probe the structural features of the H-2Kb containing a defined peptide in the antigen cleft. We report that the binding surface area of a Kb specific monoclonal antibody (28-13-3s) includes residues in the alpha 1 (Gly56 and Glu58) and alpha 2 (Trp167) helices of Kb thus, binding across the antigen binding groove. When cells treated with the antigenic peptide of vesicular stomatitis virus, N52-59, and its alanine substituted analogs were tested for 28-13-3s binding, it was found that position 1 of the peptide also forms a part of the antibody binding site. This finding strongly supports the positioning of the N-terminus of N52-59 proximal to pocket A, thus, assuming an orientation parallel to the alpha 1 helix.

Abelson murine leukemia virus↗
PubMed1992

Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA.

The BamHI Z Epstein-Barr replication activator (ZEBRA) mediates disruption of latency and induction of Epstein-Barr virus (EBV) early gene expression in latently infected lymphocytes. Polyclonal rabbit sera raised against ZEBRA were used to immunoprecipitate ZEBRA-associated proteins (ZAPs). ZAPs of 19, 21, 23, and 42 kDa were coimmunoprecipitated with ZEBRA from extracts of EBV-producing lymphoid cell lines. ZAPs were not recognized directly by the rabbit sera, but they were antigenic for EBV+ human sera. Immunoprecipitation of ZAPs by ZEBRA-specific antisera required the presence of ZEBRA. ZAPs were not coprecipitated with ZEBRA from mouse cells expressing only ZEBRA, from Raji (a cell line in which EBV is unable to complete lytic replication), or from cells treated with inhibitors of viral DNA synthesis. Thus, ZAPs are late EBV-encoded proteins. ZEBRA and ZAPs colocalized to a salt-insoluble nuclear fraction, and both were found extracellularly in crude preparations of virions. ZAPs might function to affect the cellular localization of ZEBRA, to alter its capacity to transactivate, or to influence its target gene specificity.

Cell Line↗
PubMed1992

Selective reactivity of CD8-independent T lymphocytes to a cytotoxic T lymphocyte-selected H-2Kb mutant altered at position 222 in the alpha 3 domain.

To study the structural basis for specificity and affinity of cytotoxic T lymphocytes for major histocompatibility complex/peptide complexes, we have employed a cytotoxic T lymphocyte (CTL)-mediated immunoselection approach to obtain H-2Kb structural mutants which are resistant to lysis by a Kb-specific alloreactive CTL clone. In this study we describe the Kb structural mutant, designated R8.60.14, recovered following immunoselection using the CD8-dependent CTL clone 60 as a selective agent. Although serologically unaltered with respect to Kb expression, R8.60.14 is not recognized by CD8-dependent, Kb-specific CTL. DNA sequence analysis revealed a single Glu----Lys amino acid substitution at position 222 in the Kb alpha 3-domain of this variant. To determine if a direct correlation exists between CD8 dependence of a Kb specific CTL and its failure to respond to R8.60.14, we examined the lytic response against R8.60.14 by CD8-independent, Kb-specific CTL obtained from long-term culture in the presence of anti-CD8 monoclonal antibody, 3.155. CD8-independent CTL exhibit no difference in their response against the R8 parent and R8.60.14 variant. This study demonstrates unequivocally that Kb-specific recognition of R8.60.14 by CD8-independent CTL is unaltered, while the response by CD8-dependent CTL is completely abrogated. Thus, the sole basis for emergence of this variant in the CTL-mediated immunoselection approach used in this study resides in the alteration of a single CD8-binding site residue at position 222 in the Kb alpha 3 domain. The functional importance of this Glu222 residue for the interaction between the CD8 molecule on CD8-dependent CTL and the Kb alpha 3 domain is further reinforced by virtue of the recovery of the R8.60.14 variant on the basis of its resistance to lysis by a CD8-dependent CTL clone in this CTL-mediated immunoselection approach.

Animals↗
PubMed1992

[A clinical analysis of atrial-ventricular sequential pacing].

Forty one patients were implanted DDD pacemakers (3 cases DDDR) from August, 1983 to July, 1990. 32 males and 9 females. The mean age was 62.3 years (range 32 to 91). 19 patients had coronary artery disease. The indication for pacing was II degrees-III degrees AV block in 16 patients and sick sinus syndrome in 25 patients. During follow-up period there were 2 patients had displacement, 4 patients had undersensing, 3 patients had pacemaker-mediated tachycardia and 3 patients had crosstalk. That was corrected through external programmer. The experience of this operation was discussed.

Adult↗