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Biomedical subjects

S Zhu

Publications and source records attributed to S Zhu.

At least 199 records · Page 11Linked to original sources
PubMed1998

[Effect of CD11b/CD18 on burn-activated PMN-mediated permeability of pulmonary microvascular in isolated perfused lung].

OBJECTIVE: To determine the effect of intercellular adhesion molecule (ICAM-1) CD11b/CD18 in burn-activated PMN-mediated permeability of microvascular in isolated perfused lung. METHOD: Isolated lungs were distributed into 7 groups according to the different contents of perfused fluid: normal perfused fluid, normal rat serum, burn rat serum, normal rat PMN, burn rat PMN, normal rat PMN blocked by monoclonal antibody to adhesion molecule CD11b/CD18 and burn rat PMN blocked by antibody. The extent of isolated lung edema, vascular permeability to small molecules (fluid) and vascular permeability to large molecules (albumin) were expressed by lung weight gain (LWG), fluid filtration coefficient (Kf) and pulmonary albumin permeability-surface area product (PS) respectively. RESULT: Burn serum could increase LWG, Kf PS, so did burn-activated PMN. The latter could make PS increase more obviously. Monoclonal antibody to CD11b/CD18 on PMN could obviously decrease PMN sequestration in isolated perfused lung. The protective effect of antibody on increasing LWG and Kf, and particularly PS was demonstrated. CONCLUSION: (1) The effect of mediators from burn-activated PMN to EC was mediated by PMN adhesion to EC. (2) Some mediators from burn-activated PMN increase mainly the pulmonary vascular permeability to small molecules, and PMN adhesion to EC mediated by CD11b/CD18 may increase directly the permeability to large molecules. (3) Adhesion molecule CD11b/CD18 perhaps have an ability to regulate directly EC by combining its receptor ICAM-1 on EC.

Animals↗
PubMed1998

[Hard nucleus cataract extraction by phacoemulsification with intraocular lens implantation].

OBJECTIVE: To investigate the technique of phacoemulsification for hard nucleus cataract extraction and evaluate its therapeutic effects. METHODS: Three methods of phacoemulsification, the improved divide and conquer, the reserve lens cortex spin and no lens cortex spin, were performed on 62 eyes according to the type of nucleus hardness. RESULTS: With foldable or 5.5 mm PMMA intraocular lens implantation, the improved divide and conquer phacoemulsification was performed on 26 eyes, the reserve lens cortex spin phacoemulsification on 23 eyes and no cortex spin phacoemulsification on 13 eyes. At postoperative 3 days, 5 days and 30 days, the visual acuities without correction 0.5 or better were obtained respectively in 46 eyes (74.2%), 60 eyes (96.8%) and 61 eyes (98.4%). The major complications were corneal edema and posterior capsular rupture. CONCLUSION: The technique of phacoemulsification for hard nucleus cataract is worthy to be spread due to safety, easiness and minimum complication.

Aged↗
PubMed1998

[Hemorrheologic analyses of anterior ischemic optic neuropathy].

OBJECTIVE: To find the pathogenic factor of non-temporal arteritis anterior ischemic optic neuropathy (AION). METHODS: Several items of hemorheology in 39 cases (19 males and 20 females) of acute non-temporal arteritis AION at papilloedema stage were examined and compared with that of the control group including normal comparable 20 males and 20 females. RESULTS: The results showed that hematocrit (HCT), fibrinogen, low shearing viscosity, aggregation index, erythrocyte electrophoresis time were higher in the AION group than that of the control group (P < 0.01 or P < 0.05). Besides, high shearing viscosity and plasma viscosity in the female patient group are also higher than that of the control group (P < 0.01). CONCLUSION: The high blood viscosity is closely related to the pathogenesis of non-temporal arteritis AION.

Blood Viscosity↗
PubMed1998

[The survey of anterior chamber angle in a population of middle and old age].

OBJECTIVE: To determine the condition of anterior chamber angle in a population of middle and old age, and afford data for screening of angle closure glaucoma. METHODS: Two hundred people aged 50 years or older were selected by random sampling in four districts of Doumen county. The anterior chamber angle of all people was evaluated by Goldmann one-mirror gonioscope, and the angle was graded according to the Spaeth and Shaffer's grading system. RESULTS: Three hundred ninety eyes were examined, 12% (inferior angle) to 30% (superior angle) were Shaffer's grade <or= 2. 11.3% (inferior) to 26.4% (superior) were anterior bowing of the peripheral portion of the iris, 27.7% (inferior) to 42.6% (superior) were iris insertion into seleral spur. The three aspects of the angle had significant differences in sex and age. CONCLUSION: The survey shows that the percentage of people with occludable angles increases significantly with age, and women with occludable angles are more than men. This result is important for us to make screening strategy of primary angle-closure glaucoma.

Adult↗
PubMed1998

[Intraocular pressure rise early after phacoemulsification with posterior chamber lens implantation].

OBJECTIVE: To investigate intraocular pressure (IOP) changes early after phacoemulsification with posterior chamber lens implantation. METHODS: The IOP was measured in 49 patients 53 eyes before and 10 - 12, 22 - 24, 46 - 48 hours after the operation. RESULTS: The IOP increased obviously in all eyes 10 - 12 hours after the operation, and rose more significantly from the baseline to the maximum 10 - 12 hours after surgery in 20 sutured eyes than that in 33 unsutured eyes (t = 4.41 and 3.32, P = 0.0001 and 0.0020, respectively). It was higher than 3 kPa in 16 eyes, 10 (10/20, 50.0%) in the sutured group, 6 (6/33, 18.2%) in the unsutured group, respectively, and the difference was significant between the two groups (chi2=5.9820, P=0.014). The IOP decreased markedly 22 - 24 hours, and returned to the baseline level 46 - 48 hours after the operation. CONCLUSION: These results indicate that IOP increases early after phacoemulsification with posterior chamber lens implantation, especially in sutured eyes. Therefore, to apply corresponding management properly in time and obtain better therapeutic effects of the operation, IOP should be measured regularly.

Adult↗
PubMed1998

Interleukin-1 receptor antagonist suppresses Langerhans cell activity and promotes ocular immune privilege.

PURPOSE: To determine whether the capacity of Langerhans cells (LCs) to abrogate ocular immune privilege can be suppressed by the topical application of interleukin-1 receptor antagonist (IL-1ra). METHODS: Cautery was applied to corneas of BALB/c mice on day 0 to induce centripetal migration of LCs. Immune privilege was tested by the ability to induce anterior chamber-associated immune deviation (ACAID) to intracamerally injected soluble antigen 1 to 2 weeks after cautery application. The number of LCs was enumerated by immunofluorescent staining. In other experiments, freshly procured Thy-1-depleted epidermal cells, with or without LC depletion, were injected directly into virgin murine corneas before testing for ACAID. All test animals were randomized for treatment with either topical IL-1ra or placebo in a masked fashion for 1 to 2 weeks after induction of LC migration and before intracameral injection of antigen. RESULTS: Intracorneal injection of freshly procured LC-depleted epidermal cells into normal eyes failed to abrogate ACAID, whereas LC-containing cell populations uniformly led to loss of immune privilege (P < 0.01). Topical treatment with IL-1ra led to retention of the cauterized eyes' capacity for ACAID induction (P < 0.01) and to a profound (>80%) suppression of LC migration compared with untreated controls (P < 0.01). Additionally, topical IL-1ra treatment of eyes with intracorneally injected LCs preserved immune privilege and ACAID induction (P < 0.001). CONCLUSIONS: IL-1 mediates mechanisms of immunity in corneal inflammation that subvert the normal eye's immune privileged state. However, its antagonism with topical administration of IL-1ra preserves ocular immune privilege and ACAID through suppression of LC function.

Administration, Topical↗
PubMed1998

[Gene diagnosis of 10 Chinese families with adult polycystic kidney disease from Guangxi region].

OBJECTIVE: To study presymptomatic gene diagnosis in adult polycystic kidney disease (APKD). METHODS: Linkage analysis and haplotype characterization were carried out in 10 unrelated Chinese APKD families from Guangxi region, including 97 individuals and 29 affected members. Members of these families were ultrasonographically examined. Linkage to PKD1 was investigated in all families with four microsatellite markers(SM7, CW2, AC2.5, and KG8). These flanking markers were amplified by PCR. RESULTS: The families were fully informative for gene diagnosis and no evidence of genetic heterogeneity was found. DNA analysis predicted 7 asymptomatic individuals(by 28 years old) as being affected, although they all presented negative ultrasonographs. CONCLUSION: Linkage analysis is still an important way in APKD presymptomatic gene diagnosis.

Adult↗
PubMed1998

Synthesis and biological activity of binuclear platinum complexes containing two monofunctional cis-[Pt(NH3)2Cl]+ units bridged by 4,4'-dipyridyl selenides or sulfides.

The synthesis of four binuclear platinum complexes of general formula ¿cis-[Pt(NH3)2Cl]2(L)¿ (NO3)2 [L is 4,4'-dipyridyl sulfide (compound I), 4,4'-dipyridyl selenide (compound II), bis(3-methyl-4-pyridyl) sulfide (compound III) or bis(3-methyl-4-pyridyl) selenide (compound IV)] has been achieved. These compounds have been characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and 195Pt-NMR spectroscopy. The above dinuclear platinum complexes have been assayed for antitumor activity in vitro against the cisplatin-sensitive L1210 (the mice leukemia) and cisplatin-insensitive HCT8 (the human coloadenocarcinoma) cell lines. The compounds show IC50 values comparable to or higher than cisplatin against L1210 cell line; however, they have lower IC50 values than cisplatin against the cisplatin-insensitive HCT8 cell line. The complexes containing S exhibit a cytotoxicity against the two cancer cell lines superior to the Se analogues. DNA binding studies indicate the compound I possibly interacts with DNA nonintercalatively. The mode of DNA binding of the dinuclear Pt(II) complexes bridged by 4,4'-dipyridyl selenides or sulfides may be different to that of the aliphatic diaminebridged dinuclear Pt(II) complexes reported previously.

Animals↗
PubMed1998

Alpha-fetoprotein derived from a human hepatoma prevents growth of estrogen-dependent human breast cancer xenografts.

Alpha-fetoprotein (AFP) is a transport protein that has growth-regulatory properties in many different tissues. It is known to interfere with responses stimulated by estrogen. The purpose of this study was to determine whether human AFP would inhibit the growth of human breast cancer. AFP was isolated from the culture supernatant of human hepatoma cells (HepG2) grown in serum-free medium and was purified by immunoaffinity chromatography. Human breast cancers were grown as xenografts under the kidney capsule of severe combined immunodeficient mice. The minimum inhibitory dose of AFP against estradiol (E2)-stimulated growth of human MCF-7 breast cancer xenografts was 10 microg/mouse/day, and maximum inhibition (no growth) was achieved with 100 microg/mouse/day. Daily treatment was required to sustain inhibition. This 100-microg dose of AFP also inhibited xenograft growth of E2-dependent T47 human breast carcinoma. Estrogen receptor-negative MDA MB 231 and BT20 human breast carcinoma xenografts were not inhibited by AFP (100 microg/mouse/day). Elevation in serum E2 occurred during AFP treatment. AFP did not compete with agonists for the estrogen receptor. These laboratory results are consistent with the findings of a literature search, which consistently showed an association between elevated pregnancy levels of AFP and subsequent reduced risk for breast cancer later in life. We conclude that AFP can inhibit growth of estrogen-dependent breast cancer and warrants further development as an agent for the treatment and perhaps even the prevention of human breast cancer.

Animals↗
PubMed1997

Ribosome targeting of PKR is mediated by two double-stranded RNA-binding domains and facilitates in vivo phosphorylation of eukaryotic initiation factor-2.

Protein kinase PKR is activated in mammalian cells during viral infection, leading to phosphorylation of the alpha subunit of eukaryotic initiation factor-2 (eIF-2alpha) and inhibition of protein synthesis. This antiviral response is thought to be mediated by association of double-stranded RNA (ds-RNA), a by-product of viral replication, with two ds-RNA-binding domains (DRBDs) located in the amino terminus of PKR. Recent studies have observed that expression of mammalian PKR in yeast leads to a slow growth phenotype due to hyperphosphorylation of eIF-2alpha. In this report, we observed that while DRBD sequences are required for PKR to function in the yeast model system, these sequences are not required for in vitro phosphorylation of eIF-2alpha. To explain this apparent contradiction, we proposed that these sequences are required to target the kinase to the translation machinery. Using sucrose gradient sedimentation, we found that wild-type PKR was associated with ribosomes, specifically with 40 S particles. Deletions or residue substitutions in the DRBD sequences blocked kinase interaction with ribosomes. These results indicate that in addition to mediating ds-RNA control of PKR, the DRBD sequences facilitate PKR association with ribosomes. Targeting to ribosomes may enhance in vivo phosphorylation of eIF-2alpha, by providing PKR access to its substrate.

Biological Transport↗
PubMed1997

Efficacy of immunosuppressive drugs in islet xenotransplantation: leflunomide in combination with cyclosporine and mycophenolate mofetil prevents islet xenograft rejection in the pig-to-rat model.

BACKGROUND: Morphological characteristics of islet xenograft rejection differ from those of islet allograft rejection. Therefore, prevention of islet xenograft rejection probably requires a different type of immunosuppression from that used in allogeneic transplantation. METHODS: Fetal porcine islet-like cell clusters (ICC) were transplanted into the renal subcapsular space of rats treated with different immunosuppressive protocols. The existence of a cellular infiltrate or deposits of antibodies and complement in the grafts was evaluated at different times after transplantation using immunohistochemistry. RESULTS: Treatment with leflunomide (LEF), cyclosporine (CsA), mycophenolate mofetil (MMF), 15-deoxyspergualin, and rapamycin alone or in combination had an insufficient inhibitory effect on ICC xenograft rejection. However, in animals treated with LEF+CsA, the rejection process was markedly inhibited. However, some macrophages and T cells were still present, and at 24 days, the xenografts were destroyed. In LEF+CsA-treated animals that were given sera containing an excessive amount of rat anti-porcine xenoreactive antibodies, marked deposits of IgG, and to some extent C3 as well, were detected along the border between intact ICC, and the xenografts were surrounded by macrophages. However, almost no cells infiltrated the grafts, and there were many intact ICC. In animals treated with LEF+CsA+MMF, only occasional infiltrating cells were seen at 12 and 24 days after transplantation, and the endocrine tissue was completely intact. CONCLUSIONS: LEF+CsA+MMF prevented rejection of porcine ICC xenografts in the rat for up to 24 days after transplantation.

Animals↗
PubMed1997

RhoGDIgamma: a GDP-dissociation inhibitor for Rho proteins with preferential expression in brain and pancreas.

GDP-dissociation inhibitors (GDIs) play a primary role in modulating the activation of GTPases and may also be critical for the cellular compartmentalization of GTPases. RhoGDI and GDI/D4 are two currently known GDIs for the Rho-subfamily of GTPases. Using their cDNAs to screen a human brain cDNA library under low stringency, we have cloned a homologous cDNA preferentially expressed at high levels in brain and pancreas. The predicted protein, named RhoGDIgamma, is approximately 50% identical to GDI/D4 and RhoGDI. It binds to CDC42 and RhoA with less affinity compared with RhoGDI and does not bind with Rac1, Rac2, or Ras. RhoGDIgamma functions as a GDI for CDC42 but with approximately 20 times less efficiency than RhoGDI. Immunohistochemical studies showed a diffuse punctate distribution of the protein in the cytoplasm with concentration around the nucleus in cytoplasmic vesicles. Overexpression of the protein in baby hamster kidney cells caused the cells to round up with loss of stress fibers. A distinct hydrophobic amino terminus in RhoGDIgamma, not seen in the other two RhoGDIs, could provide a mechanism for localization of the GDI to specific membranous compartment thus determining function distinct from RhoGDI or GDI/D4. Our results provide evidence that there is a family of GDIs for the Rho-related GTPases and that they differ in binding affinity, target specificity, and tissue expression. We propose that RhoGDI be renamed RhoGDIalpha and GDID4 be renamed RhoGDIbeta. The new GDI should widen the scope of investigation of this important class of regulatory protein.

Amino Acid Sequence↗
PubMed1997

p53 mutation as a prognostic marker in advanced laryngeal carcinoma. Department of Veterans Affairs Laryngeal Cancer Cooperative Study Group.

OBJECTIVE: To determine the relationship of p53 mutations in advanced laryngeal carcinomas to p53 immunohistochemistry, organ preservation, and patient survival. DESIGN: Paraffin-embedded tumor specimens were obtained from patients enrolled in the Department of Veterans Affairs Laryngeal Cancer Cooperative Study, a multi-institutional randomized clinical trial comparing induction chemotherapy (cisplatin and fluorouracil) plus radiation therapy surgery plus postoperative radiation therapy. Tumor specimens were analyzed for p53 mutations in exons 5 through 8 by using single-strand conformational polymorphism (SSCP) analysis followed by DNA sequencing of all variants. Five-year follow-up data were available for all patients studied. SUBJECTS: Forty-four patients enrolled in the Department of Veterans Affairs Laryngeal Cancer Cooperative Study from whom paraffin-embedded tumor specimens were readily available. RESULTS: p53 immunostaining did not correlate with p53 SSCP and DNA sequencing results. More than half (62% [16/26]) of the tumors that overexpressed p53 immunohistochemically did not have a detectable p53 gene mutation. Similarly, 39% (7/18) of tumors that did not overexpress p53 did have a p53 gene mutation. p53 mutations were present in 39% of tumors tested. Mutations within exon 5 made up 41% of p53 gene mutations in laryngeal carcinomas. Transitions were the most common type of mutation in this study (92% of mutations). CONCLUSIONS: The presence of a p53 mutation as detected by SSCP is associated with decreased patient survival. Further study is required to confirm this relationship and to determine whether specific p53 mutations predict organ preservation.

Carcinoma, Squamous Cell↗
PubMed1997

Identification and characterization of growth hormone receptors in snakehead fish (Ophiocephalus argus cantor) liver.

The specific binding of 125I-labeled fish growth hormone (GH) to hepatic membranes prepared from several freshwater fish was assessed. A high level of growth hormone receptor (GHR) was detected on the hepatic membranes of the snakehead fish (Ophiocephalus argus Cantor). Scatchard analysis of the binding data showed a single class of high affinity binding site with a binding affinity (Ka) of 1.45 +/- 0.23 x 10(9) M-1 and a binding capacity (Bmax) of 198 +/- 57 fmol/mg protein. The binding was specific for fish GH and was saturable. In addition, the specific binding was temperature- and time-dependent, reaching a steady state after 16 hr of incubation at 25 degrees . The molecular weight of GHR as measured by Sephadex G-200 column chromatography and Western blot analysis using a monoclonal antibody (Mab263) against GHR was found to be 200-400 and 90-93 kDa, respectively. Two bands at 65 and 89 kDa were identified in ligand crosslinking studies of membrane receptors. A sensitive teleost GH radioreceptor assay (RRA) was developed, using recombinant fish GH and a membrane preparation from snakehead fish liver, capable of measuring bioactive GH in fish sera or other samples.

Animals↗
PubMed1997

Combined effects of hand-arm vibration and noise on temporary threshold shifts of hearing in healthy subjects.

OBJECT: To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects. METHOD AND DESIGN: Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s2, 60 Hz), noise [90 dB(A)] and both, respectively. The subject's right hand was placed on the plate of a vibrator and the right ear exposed to noise via headphones. Subjects were exposed to vibration and/or noise for 3 min and after a 1-min pause the exposure was repeated five times. Hearing thresholds at 1, 4 and 6 kHz were measured during the time periods before, between (during pauses) and after exposure. RESULTS: Exposure to vibration alone caused almost no hearing threshold changes at every frequency tested. But exposure to noise or a combination of vibration and noise caused a significant increase in TTSs at 4 and 6 kHz. Moreover, exposure to a combination of vibration and noise caused significantly higher TTSs than exposure to noise at 4 and 6 kHz. CONCLUSION: The present results demonstrate the combined effects of hand-arm vibration and noise can enhance exposure to hand-arm vibration and noise can enhance the TTS of hearing more than noise exposure, though hand-arm vibration alone may hardly affect TTS.

Adult↗
PubMed1997

Electron microscopic observation on a non-occluded baculo-like virus in shrimps.

A severe disease of farm-raised shrimp, Penaeus chinensis has spread throughout Chinese coasts since 1993. Recently, a baculo-like virus has been diagnosed as the causative agent for this epidemic disease. The electron microscopic observation of the virus is described. Thin sections of hepatopancreatic and hypodermic tissue of diseased P. chinensis showed many rod-shaped, enveloped, baculo-like virions in hypertrophied nuclei of infected cells. The virion was filled with a highly electron dense core. No occlusion bodies have been found. Negative stained intact virions, purified from infected tissues by centrifugation on sucrose discontinuous gradients, demonstrated that the viral envelops had been broken, but the cylindrical nucleocapside could be observed clearly. The nucleocapsid of average 62 nm x 314 nm was composed of a helix system of capsomers, giving rise to an open stacked ring structure and repeating approximately every third ring. The number of repeating unit was 13 to 15. We propose that the virus described here could be designated as Non-Occluded Shrimp Virus (NOSV) or Penaeus chinensis Baculo-Like Virus (PcBLV).

Animals↗