PubMed Health⌕ Search

Biomedical subjects

Y F Yang

Publications and source records attributed to Y F Yang.

At least 19 recordsLinked to original sources
PubMed2006

Decreased levels of apolipoprotein A-I in plasma of schizophrenic patients.

This study aims to identify the effects of antipsychotics on plasma proteins, and on the proteins associated with schizophrenia. We applied proteomics technology to screen protein aberrations in Sprague-Dawley rats treated with antipsychotics and schizophrenic patients undergoing medication. ApoA-I was found significantly increased in the chlorpromazine-treated rats and decreased in the patients with treatment-resistant schizophrenia, which suggest that decreased levels of apoA-I might be associated with the pathology of schizophrenia and that chlorpromazine increases apoA-I levels as part of its therapeutic action.

Adult↗
PubMed2006

Scleral-fixated posterior chamber intraocular lenses in non-vitrectomized eyes.

OBJECTIVE: To assess the long-term outcome of scleral-fixated sutured posterior chamber intraocular lens (SPCIOL) implantation in non pars plana vitrectomised eyes (1) to evaluate the long-term visual outcome, (2) to identify preoperative risk factors for poor visual outcomes, and (3) to identify the incidence of vitreoretinal complications. METHOD: A retrospective review of 65 eyes, which had not undergone pars plana vitrectomy prior to scleral-fixated SPCIOL implantation. RESULTS: In all, 65 eyes of 61 patients were analysed. The median follow-up period was 16 months (range 1-68 months). At final follow-up, 43 (66%) eyes had unchanged or improved BCVA at final follow-up. A total of 20 (31%) eyes had at least a two line improvement and eight (12%) eyes had at least a two line deterioration in final BCVA. No significant preoperative risk factors for a poor visual outcome were identified. In all, 24 eyes (37%) had per- and postoperative adverse events. These eyes were significantly more likely to have a poor visual outcome. Three eyes (4.6%) had a retinal detachment in the postoperative period, all of which had no perception of light at final follow-up. CONCLUSIONS: This study confirmed that while scleral-fixated SPCIOL intraocular lens implantation might be beneficial, there is a significant risk of per- and postoperative complications leading to loss of best-corrected vision in some eyes.

Adolescent↗
PubMed2005

Possible association of the MAG locus with schizophrenia in a Chinese Han cohort of family trios.

Neurotransmitter-based hypotheses have so far led to only moderate success in predicting new pathogenetic findings in etiology of schizophrenia. On the other hand, the more recent oligodendroglia hypotheses of this disorder have been supported by an increasing body of evidence. For example, the expression level of the myelin associated glycoprotein (MAG) gene has been shown to be significantly lower in schizophrenia patient groups compared to control groups. Such an effect might be a result of genetic variations of the MAG gene. In order to test this hypothesis, we genotyped four markers within the MAG locus in 413 trios sample of the Han Chinese using allele-specific PCR. None of the four markers revealed noticeable allelic significance. However, the four-marker and two-marker haplotypes covering components rs720309 and rs720308 were observed to be significantly associated with schizophrenia (P < 0.0001) in this study. In addition, we identified one common risk haplotype TA (rs720309-rs720308, present in 78.5% of the general population) that showed increased evidence of overtransmission from parents to affected offspring (P = 0.0001). The results demonstrated MAG might play a role in genetic susceptibility to schizophrenia. Furthermore, our finding of a possible association between the MAG locus and schizophrenia is in agreement with the hypotheses of oligodendrltic and myelination dysfunction.

Adult↗
PubMed2005

Retinal detachment following surgery for congenital cataract: presentation and outcomes.

AIMS: To review the current management and outcomes of retinal detachment following cataract surgery in childhood. METHODS: A retrospective review of 59 eyes of 52 patients. RESULTS: In 37% of patients, the fellow eye was blind (<3/60). The macula was detached at presentation in 81% of eyes. The detachment was obscured by residual lens matter, or a miotic pupil in 67% of eyes that had cataract surgery before 1970, but in only 30% of eyes operated after 1970. The retina was reattached with one operation in 59% of eyes, and final reattachment was achieved in 81%. No retina was reattached by scleral buckling alone. Visual outcomes were slightly better in eyes that had retinal detachment repair after 1 January 1998. Nine patients were blind in both eyes at the latest follow-up. CONCLUSIONS: Retinal detachment following childhood cataract surgery remains a serious condition. There has been some improvement in the prognosis due to a combination of advances in childhood cataract surgery as well as to improvements in the management of retinal detachment. Early recognition and prompt surgery, using an internal approach, may prevent blindness in most cases.

Adult↗
PubMed2004

Transmission disequilibrium analysis of the GSN gene in a cohort of family trios with schizophrenia.

Apoptosis is thought to play a role in neuronal pathology in schizophrenia. Recently, the GSN gene was reported to have anti-apoptotic properties. In a genome-wide expression analysis on schizophrenia, GSN was also found to be significantly down-regulated in schizophrenia. All the hints suggest that GSN is a novel candidate gene in occurrence of schizophrenia. In this work, we genotyped 3 SNPs around the GSN locus in 493 sets of the Han Chinese trio sample using allele-specific PCR. A weak association or a marginally positive result was detected (0.05 for P-value of the overtransmitted haplotype and 0.02 for a global P-value).

Adult↗
PubMed2004

Confirmation and refinement of a genetic locus for disseminated superficial actinic porokeratosis (DSAP1) at 12q23.2-24.1.

BACKGROUND: Our previous study has identified two loci for disseminated superficial actinic porokeratosis (DSAP), but the genes responsible are still unknown. OBJECTIVES: To narrow down the candidate regions and to assess candidate genes. METHODS: A genome-wide scan and linkage analysis were carried out in a newly collected five-generation Chinese family with DSAP. In addition, six candidate genes were screened for possible DSAP-associated mutations. RESULTS: DSAP in this family was associated with chromosome 12q. Fine mapping and haplotype construction refined the DSAP1 locus to a 4.4-cM interval. No disease-associated mutation was detected in CRY1, C4ST1, TXNRD1, HCF2, CMKLR1 or KIAA0789 genes. CONCLUSIONS: The DSAP1 locus was localized to a 4.4-cM interval at chromosome 12q23.2-24.1. CRY1, C4ST1, TXNRD1, HCF2, CMKLR1 and KIAA0789 genes were not associated with DSAP1.

Adolescent↗
PubMed2002

A novel locus (DSAP2) for disseminated superficial actinic porokeratosis maps to chromosome 15q25.1-26.1.

BACKGROUND: Disseminated superficial actinic porokeratosis (DSAP) is a chronic cutaneous disorder characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. It develops in teenagers in sun-exposed areas of skin and usually follows an autosomal dominant inheritance pattern. The first locus for DSAP was localized to chromosome 12q23.2-24.1, but no gene responsible for porokeratosis has been identified to date. OBJECTIVES: To determine whether DSAP is a genetically heterogeneous disorder and to identify the disease gene locus in a three-generation Chinese family with DSAP. METHODS: Genetic linkage analysis was carried out in this family using 15 microsatellite markers between D12S1671 and D12S369 on chromosome 12q, followed by a genome-wide scan with 382 microsatellite markers from the autosomes. RESULTS: Genetic linkage analysis with chromosome 12q markers suggested that the locus in this family is not linked to chromosome 12q. A genome-wide scan and fine mapping finally localized the locus for DSAP in this family to a 6.4-cM region between markers D15S1023 and D15S1030 at chromosome 15q25.1-26.1. This DSAP locus was named DSAP2. CONCLUSIONS: The previous results and this study have shown that DSAP is a genetically heterogeneous disorder; a novel locus for DSAP, termed DSAP2, was mapped to a 6.4-cM region between markers D15S1023 and D15S1030.

Adolescent↗
PubMed2002

Evidence for the existence of a constitutive nitric oxide synthase in vascular smooth muscle.

1. We have identified a neuronal nitric oxide synthase (NOS)-like constitutive form of NOS in vascular smooth muscle (VSM) using a functional contractility approach as well as immunohistochemical methods. 2. N(G)-Nitro-L-arginine methyl ester, N(G)-monomethyl-L- arginine and N(G)-nitro-L-arginine (L-NOARG), the competitive inhibitors of NOS, inhibited Mg(2+)-induced relaxation of de-endothelialized rat aorta precontracted with phenylephrine (PE). This Mg(2+) relaxation of VSM was not affected by inhibitors of inducible NOS. 3. Electrical field stimulation (EFS; 30-70 Hz) caused relaxation of rat aorta in the presence of tetrodotoxin (therefore not a neurogenic effect) and this EFS relaxation was effectively inhibited by L-NOARG, oxyhemoglobin and methylene blue. 4. Immunohistochemical studies of dog saphenous vein using antibodies raised against neuronal NOS indicated prominent staining along the plasmalemma in a punctate pattern similar to the distribution of antibodies against caveolin-1, a major constituent of the plasmalemmal caveolae. 5. We propose that a constitutive NOS of non-endothelial, non-neuronal origin is present in a special caveolae domain of VSM cell membranes and could be activated by an ionic mechanism yet to be characterized.

Animals↗
PubMed2001

A mandatory role for STAT4 in IL-12 induction of mouse T cell CCR5.

IL-12 was recently shown to induce CCR5 on TCR-triggered mouse T cells. Considering that STAT4 is the most critical of IL-12 signaling molecules, this study investigated the role for STAT4 in the induction of CCR5 expression. IL-12R was induced by stimulation with anti-CD3 plus anti-CD28 mAb similarly on T cells from wild-type (WT) and STAT4-deficient (STAT4(-/-)) mice, but the levels of IL-12R induced on IFN-gamma-deficient (IFN-gamma(-/-)) T cells were lower compared with WT T cells. Exposure of TCR-triggered WT T cells to IL-12 induced CCR5 expression. In contrast, TCR-triggered STAT4(-/-) T cells failed to express CCR5 in response to IL-12. IL-12 stimulation induced detectable albeit reduced levels of CCR5 expression on IFN-gamma(-/-) T cells. Addition of rIFN-gamma to cultures of IFN-gamma(-/-) T cells, particularly to cultures during TCR triggering resulted in restoration of CCR5 expression. However, CCR5 expression was not induced in STAT4(-/-) T cells by supplementation of rIFN-gamma. These results indicate that for the induction of CCR5 on T cells, 1) STAT4 plays an indispensable role; 2) such a role is not substituted by simply supplementing rIFN-gamma; and 3) IFN-gamma amplifies CCR5 induction depending on the presence of STAT4.

Animals↗
PubMed2001

Oral immunization with hepatitis B surface antigen expressed in transgenic plants.

Oral immunogenicity of recombinant hepatitis B surface antigen (HBsAg) derived from yeast (purified product) or in transgenic potatoes (uncooked unprocessed sample) was compared. An oral adjuvant, cholera toxin, was used to increase immune responses. Transgenic plant material containing HBsAg was the superior means of both inducing a primary immune response and priming the mice to respond to a subsequent parenteral injection of HBsAg. Electron microscopy of transgenic plant samples revealed evidence that the HBsAg accumulated intracellularly; we conclude that natural bioencapsulation of the antigen may provide protection from degradation in the digestive tract until plant cell degradation occurs near an immune effector site in the gut. The correlate of protection from hepatitis B virus infection is serum antibody titers induced by vaccination; the protective level in humans is 10 milliunits/ml or greater. Mice fed HBsAg-transgenic potatoes produced HBsAg-specific serum antibodies that exceeded the protective level and, on parenteral boosting, generated a strong long-lasting secondary antibody response. We have also shown the effectiveness of oral delivery by using a parenteral prime-oral boost immunization schedule. The demonstrated success of oral immunization for hepatitis B virus with an "edible vaccine" provides a strategy for contributing a means to achieve global immunization for hepatitis B prevention and eradication.

Animals↗
PubMed2001

Nuclear stopping as a probe for in-medium nucleon-nucleon cross sections in intermediate energy heavy ion collisions.

Using an isospin-dependent quantum molecular dynamics, nuclear stopping in intermediate heavy ion collisions has been studied. The calculation has been done for colliding systems with different neutron-proton ratios in beam energy ranging from 15 MeV/ u to 150 MeV/ u. It is found that, in the energy region from above Fermi energy to 150 MeV/ u, nuclear stopping is very sensitive to the isospin dependence of in-medium nucleon-nucleon cross section, but insensitive to symmetry potential. From this investigation, we propose that nuclear stopping can be used as a new probe to extract the information on the isospin dependence of in-medium nucleon-nucleon cross section in intermediate energy heavy ion collisions.

Journal Article↗
PubMed2001

IL-12 as well as IL-2 upregulates CCR5 expression on T cell receptor-triggered human CD4+ and CD8+ T cells.

The expression of chemokine receptors on leukocytes is related to their activation state. However, the exact mechanism underlying the induction of each chemokine receptor is poorly understood. Here, we investigated how CCR5, a chemokine receptor implicated in T cell trafficking and HIV infection, is induced in human T cells. CCR5 was marginally detected on a freshly prepared human peripheral blood mononuclear cell (PBMC) population. Long-term (8-day) stimulation of PBMC with IL-2 resulted in high levels of CCR5 expression on T cells. IL-12 failed to induce CCR5 on T cells in such a directly stimulated PBMC population. Stimulation of PBMC T cells with anti-CD3 plus anti-CD28 induced detectable albeit very low levels of CCR5 along with the induction of IL-12 receptor. However, these TCR-triggered T cells expressed much higher levels of CCR5 when stimulated with IL-12. Although IL-2 also induced CCR5 expression, CCR5 expression was more potent in IL-12 than IL-2 stimulation. These results indicate that, in addition to IL-2, IL-12 plays an important role in the induction of CCR5 expression on T cells, particularly TCR-triggered T cells.

CD4-Positive T-Lymphocytes↗
PubMed2001

IFN-alpha acts on T-cell receptor-triggered human peripheral leukocytes to up-regulate CCR5 expression on CD4+ and CD8+ T cells.

Interleukin-12 (IL-12) as well as IL-2 was recently shown to up-regulate CCR5 expression on T-cell receptor (TCR)-triggered human T cells. Because of the functional similarity between interferon-alpha (IFN-alpha) and IL-12, the present study investigated whether IFN-alpha also up-regulates T cell CCR5 expression. CCR5 was marginally detected on T cells from unstimulated human peripheral blood leukocytes (PBLs) and only slightly induced on PBL T cells following stimulation with anti-CD3 plus anti-CD28 monoclonal antibodies (mAbs). When anti-CD3/anti-CD28-triggered PBLs were exposed to IFN-alpha, T cells expressed high levels of CCR5. The levels of CCR5 expression were comparable to those induced by IL-12. However, when purified T cells instead of unfractionated PBL were stimulated with anti-CD3/CD28 and then exposed to IL-12 or IFN-alpha, CCR5 expression was induced by IL-12 but not by IFN-alpha. IFN-alpha was found to act on anti-CD3/anti-CD28-stimulated PBL to promote their IL-12 production. Moreover, addition of anti-IL-12 mAb to IFN-alpha-stimulated cultures of anti-CD3/CD28-pretreated PBL resulted in considerable inhibition of CCR5 expression. Together, these results indicate that IFN-alpha as well as IL-12 up-regulates CCR5 expression on TCR-triggered T cells and that IFN-alpha functions not by acting directly on T cells but via enhancing IL-12 production by PBL.

CD4-Positive T-Lymphocytes↗
PubMed2001

Cryotherapy for retinopathy of prematurity: a MRI study of the surgical-anatomical relationship of the neonatal conjunctival fornices to the globe.

PURPOSE: To demonstrate the surgical-anatomical relationship of the neonatal conjunctival fornices to the globe in order to ascertain whether adequate cryotherapy is possible in infants with stage 3 retinopathy of prematurity using a trans-scleral approach without opening the conjunctiva. METHODS: Magnetic resonance (MR) scans of the orbit were performed on an adult and an infant of 38 weeks post-conceptual age with maximal posterior placement of a MR-compatible replica of the Schulenburg cryoprobe in the nasal and temporal aspects of the globe. RESULTS: In the infant MR scan, the scleral indentation produced by the probe was anterior to the equator on the nasal side and at, or just anterior to, the equator on the temporal side. Nasally, the scleral indentation reached only the more anterior part and not the posterior part of zone 2 and none of zone 1. Temporally, the scleral indentation reached the central part of zone 2 but not the posterior part of zone 2 or zone 1. CONCLUSION: The findings suggest that adequate cryotherapy with a trans-scleral approach without opening the conjunctiva is unlikely to be achieved in the more immature neonate with posteriorly located retinopathy of prematurity. To permit access of the cryoprobe to the more posterior part of the globe, one radial conjunctival incision from the corneal limbus in each quadrant may be required to achieve adequate ablation of the posterior non-vascularised retina in these high-risk infants.

Conjunctiva↗
PubMed2001

Intraocular pressure and gonioscopic findings in rural communities mesoendemic and nonendemic for onchoceriasis, Kaduna State, Nigeria.

PURPOSE: To report on glaucoma-related ocular parameters, namely intraocular pressure and peripheral anterior synechiae, in the presence of onchocercal infection. METHODS: Two computer-generated random samples of individuals were drawn from communities mesoendemic and nonendemic for onchocerciasis respectively. Applanation tonometry and gonioscopy were carried out on these individuals. RESULTS: Four hundred and thirty-six and 319 individuals from the mesoendemic and nonendemic communities were examined respectively. The mean intraocular pressure was 1.58 mmHg lower in the individuals from the mesoendemic communities compared with those from the nonendemic communities (p < 0.001) despite the prevalence of peripheral anterior synechiae being higher in the mesoendemic communities. In these communities, there was strong evidence that the prevalence of peripheral anterior synechiae increased with increasing microfilarial load. CONCLUSIONS: Onchocercal infection produces a low-grade inflammatory process, which may result in a lowering of intraocular pressure despite the formation of peripheral anterior synechiae. Glaucomatous optic nerve damage may therefore not be the primary cause of visual loss in ocular onchocerciasis as this occurs late and is probably preceded by other blinding onchocercal pathology.

Adolescent↗
PubMed2001

Agonist-mediated down-regulation of rat beta1-adrenergic receptor transcripts: role of potential post-transcriptional degradation factors.

The human beta1-adrenergic receptor (AR) and hamster beta2-AR transcripts can be post-transcriptionally regulated at the level of mRNA stability and undergo accelerated agonist-mediated degradation via interaction of their 3' untranslated regions (UTR) with RNA binding proteins. Using RNase protection assays, we have determined that chronic isoproterenol exposure of rat C6 glioma cells results in the accelerated reduction of beta1-AR mRNAs. To determine the role of cellular environment on the agonist-independent and agonist-mediated degradation of beta1-AR mRNAs, we transfected rat beta1-AR expression recombinants into both hamster DDT1MF2 cells and rat L6 cells. The rat beta1-AR mRNAs in the two transfectant cell pools retain longer agonist-independent half-lives than in the C6 environment and undergo accelerated degradation upon chronic agonist exposure. Using UV-cross-linking/immunoblot and immunoprecipitation analyses, we have determined that the rat beta1-AR 3' UTR recognizes a predominant M(r) 39,000 component, identified as the mammalian elav-like protein HuR, and several other minor components, including the heteronuclear protein hnRNP A1. HuR levels are more highly expressed in C6 cells than in DDT1MF2 and L6 cells and are induced after chronic isoproterenol treatment. Furthermore, C6 transfectants containing an HuR expression recombinant exhibit reduced beta1-AR mRNA half-lives that were statistically comparable with half-lives identified in isoproterenol-treated C6 cells. These results imply that HuR plays a potential role in the agonist-independent and agonist-mediated down-regulation of beta1-AR mRNAs.

3' Untranslated Regions↗
PubMed2001

Persistence of acanthamoeba antigen following acanthamoeba keratitis.

AIM: To investigate the hypothesis that persistent corneal and scleral inflammation following acanthamoeba keratitis is not always caused by active amoebic infection but can be due to persisting acanthamoebic antigens METHODS: 24 lamellar corneal biopsy and penetrating keratoplasty specimens were obtained from 14 consecutive patients at various stages of their disease and divided for microscopy and culture. Histological sections were immunostained and screened for the presence of Acanthamoeba cysts by light microscopy. Cultures were carried out using partly homogenised tissues on non-nutrient agar seeded with E coli. Clinical data were obtained retrospectively from the case notes of these patients. RESULTS: Of the 24 specimens, 20 were obtained from eyes that were clinically inflamed at the time of surgery. Acanthamoeba cysts were present in 16 (80%) of these 20 specimens, while only five (25%) were culture positive. Acanthamoeba cysts were found to persist for up to 31 months after antiamoebic treatment. CONCLUSION: These findings support the hypothesis that Acanthamoeba cysts can remain in corneal tissue for an extended period of time following acanthamoeba keratitis and may cause persistent corneal and scleral inflammation in the absence of active amoebic infection. In view of these findings, prolonged intensive antiamoebic therapy may be inappropriate when the inflammation is due to retained antigen rather than to viable organisms

Acanthamoeba↗