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Biomedical subjects

H S Sun

Publications and source records attributed to H S Sun.

At least 19 recordsLinked to original sources
PubMed2006

Search for invisible decays of eta and eta' in J/psi --> phi eta and phi eta'.

Using a data sample of 58 x 10(6) J/psi decays collected with the Beijing Spectrometer II detector at the Beijing Electron Positron Collider, searches for invisible decays of eta and eta' in J/psi to phi eta and phi eta' are performed. The phi signals, which are reconstructed in K+K- final states, are used to tag the eta and eta' decays. No signals are found for the invisible decays of either eta or eta', and upper limits at the 90% confidence level are determined to be 1.65 x 10(-3) for the ratio B(eta-->invisible)/B(eta --> gamma gamma) and 6.69 x 10(-2) for B(eta' --> invisible)/B(eta' --> gammagamma). These are the first searches for eta and eta' decays into invisible final states.

Journal Article↗
PubMed2006

Observation of a broad 1-- resonant structure around 1.5 GeV/c2 in the K+K- mass spectrum in J/psi-->K+K-pi0.

A broad peak is observed at low K+K- invariant mass in J/psi-->K+K-pi(0) decays found in a sample of 5.8x10(7) J/psi events collected with the BESII detector. The statistical significance of the broad resonance is much larger than 5sigma. A partial wave analysis shows that the J;{PC} of this structure is 1--. Its pole position is determined to be [1576(-55)(+49)(stat)-91+98(syst)] MeV/c(2)-i/2[818(-23)(+22)(stat)-133+64(syst)] MeV/c(2). These parameters are not compatible with any known meson resonances.

Journal Article↗
PubMed2006

Measurements of the branching fractions for psi(3770)-->D(0)D[over ](0), D+D-, DD[over ], and the resonance parameters of psi(3770) and psi(2S).

We measure the branching fractions for psi(3770)-->D(0)D[over ](0), D+D-, DD[over ], and non-DD[over ] to be (46.7+/-4.7+/-2.3)%, (36.9+/-3.7+/-2.8)%, (83.6+/-7.3+/-4.2)%, and (16.4+/-7.3+/-4.2)%, respectively. The resonance parameters of psi(3770) and psi(2S) are measured to be M_(psi(3770))=3772.2+/-0.7+/-0.3 MeV, Gamma_(psi(3770))(tot)=26.9+/-2.4+/-0.3 MeV, and Gamma_(psi(3770))(ee)=251+/-26+/-11 eV; M_(psi(2S))=3685.5+/-0.0+/-0.3 MeV, Gamma_(psi(2S))(tot)=331+/-58+/-2 keV, and Gamma_(psi(2S))(ee)=2.330+/-0.036+/-0.110 keV. We also measure the light hadron R value to be R(uds)=2.262+/-0.054+/-0.109 in the energy region from 3.660 to 3.872 GeV.

Journal Article↗
PubMed2006

Observation of a near-threshold enhancement in the omega(phi) mass spectrum from the doubly OZI-suppressed decay J/psi-->gamma(omega)phi.

An enhancement near threshold is observed in the omega(phi) invariant mass spectrum from the doubly Okubo-Zweig-Iizuka-suppressed decays of J/psi-->gamma(omega)phi, based on a sample of 5.8 x 10(7) J/psi events collected with the BESII detector. A partial wave analysis shows that this enhancement favors JP=0+, and its mass and width are M=1812(+19)(-26)(stat)+/-18(syst) MeV/c2 and Gamma=105+/-20(stat)+/-28(syst) MeV/c2. The product branching fraction is determined to be B(J/psi-->gammaX)B(X-->omega(phi))=[2.61+/-0.27(stat)+/-0.65(syst)]x10(-4).

Journal Article↗
PubMed2006

Abundantly expressed genes in pig adipose tissue: an expressed sequence tag approach.

Adipose tissue plays a critical role in metabolism, storage, and release of fatty acids in mammals. Construction of a full-length cDNA library is an effective way to understand the functional expression of genes in adipose tissue, and in addition, novel genes for further research can be found in the library. In this study, adipose tissue RNA was extracted from three 18-mo-old Lee-Sung pigs. The mRNA was isolated, reverse transcribed, and used to construct a cDNA library. After transformation, 2,880 clones were selected and sequenced. Cluster analysis was performed, and the assembled contig of each cluster was subjected to search against DNA sequences in the nucleotide databases (NCBINR/TIGRGI). These sequences were clustered into 1,527 unique sequences; 80% of the sequences were categorized as known genes, and 20% of the sequences were categorized as unknown genes. In this adipose tissue cDNA library, approximately 16% of the genes contained full-length sequences with start and stop codons. Gene ontology analysis was performed to indicate the possible functions of these genes. Genes associated with mitochondrial function were abundant and represented 10% of the total. Several fatty acid transport genes and stearoyl coenzyme A desaturase were among the most abundant genes expressed. Tissue distribution of several abundant genes was analyzed by northern analysis, and many of these genes were transcribed in porcine adipose tissue in high copy number. Our full-length sequence data and tissue distribution data can be used to decipher the functional roles exhibited by the adipocyte under various perturbations via endocrine, environmental, genetic, nutritional, pharmacological, or physiological manipulations.

Adipose Tissue↗
PubMed2005

Observation of a resonance in Chi(1835) in J/psi --> gammapi+ pi- eta-.

The decay channel J/psi --> gamma(pi)(+)pi(-)eta is analyzed using a sample of 5.8 x 10(7) J/psi events collected with the BESII detector. A resonance, the Chi(1835), is observed in the pi(+)pi(-)eta invariant-mass spectrum with a statistical significance of 7.7 sigma. A fit with a Breit-Wigner function yields a mass M = 1833.7 +/- 6.1(stat) +/- 2.7(syst) MeV/c(2), a width Tau = 67.7 +/- 20.3(stat) +/- 7.7(syst) MeV/c(2), and a product branching fraction B(J/psi --> gammaChi) . B(Chi --> pi(+)pi(-)eta) = [2.2 +/- 0.4(stat) +/- 0.4(syst)] x 10(-4). The mass and width of the Chi(1835) are not compatible with any known meson resonance. Its properties are consistent with expectations for the state that produces the strong pp mass threshold enhancement observed in the J/psi --> gammapp process at BESII.

Journal Article↗
PubMed2004

Insulin as an in vivo growth factor.

Insulin peptide has been identified to promote regeneration of axons in culture and in some in vivo model systems. Such actions have been linked to direct actions of insulin, or to cross occupation of closely linked IGF-1 receptors. In this work, we examined insulin support of peripheral nerve regenerative events in mice. Systemic insulin administration accelerated the reinnervation of foot interosseous endplates by motor axons after sciatic nerve transection and enhanced recovery of functional mouse hindpaw function. Similarly, insulin accelerated the regeneration-related maturation of myelinated fibers regrowing beyond a sciatic nerve crush injury. That such benefits might occur through direct signaling on axons was supported by immunohistochemical studies of expression with an antibody directed to the beta insulin receptor (IR) subunit. The proportion of sensory neurons expressing IRbeta increased ipsilateral to a similar sciatic crush injury in the L4 and L5 dorsal root ganglia. Insulin receptors, although widely expressed in axons, were also preferentially and intensely expressed on axons regrowing just beyond a peripheral nerve crush injury zone. The findings indicate that insulin imparts a substantial impact on regenerating peripheral nerve axons through upregulation of its expression following injury. Although the findings do not exclude insulin coactivating IGF-1 receptors during regeneration, its own receptors are present and available for action on injured nerves.

Animals↗
PubMed2004

Association of tryptophan hydroxylase gene polymorphism with depression, anxiety and comorbid depression and anxiety in a population-based sample of postpartum Taiwanese women.

Depression and anxiety disorders often coexist clinically and both are known to have a genetic basis, but the mode of inheritance is too complicated to be determined so far. Serotonin is the biogenic amine neurotransmitter most commonly associated with depression and anxiety. Since tryptophan hydroxylase (TPH1) is the rate-limiting enzyme in serotonin biosynthesis, its role in the pathophysiology of these psychiatric diseases has been intensively studied. In this study, we examined whether polymorphism of the TPH1 gene is related to the etiology of major depression, anxiety and comorbid depression and anxiety. Five single nucleoside polymorphisms of the TPH1 gene were studied in a population-based sample of postpartum Taiwanese women consisting of 120 subjects with depression or/and anxiety and 86 matched normal controls. A significant difference (P = 0.0107) in genotype frequency for the T27224C polymorphism was found between the comorbid and normal groups, and risk analysis showed that the C allele conferred a strong protective effect (odds ratio = 0.27; 95% confident interval = 0.11-0.7). Three-allele haplotypes involving T27224C polymorphism were constructed and haplotype associations between particular haplotype combinations and various diseases identified. However, the associations were weak and the overall haplotype frequency profiles in all groups were similar. The results suggest that depression, anxiety, and comorbid depression and anxiety disorders may have related etiologies. In addition, this study suggests that the TPH1 gene might play a role in the pathogenesis of these closely related disorders.

Adult↗
PubMed2003

Endoscopic hemoclipping using a transparent cap in technically difficult cases.

BACKGROUND AND STUDY AIMS: Technical difficulties have been experienced in endoscopic hemoclipping on the posterior wall of the body of the stomach because the angle of approach is tangential. It has been suggested that the use of a transparent cap on the tip of the endoscope could help to solve this problem. The purpose of this study was to examine the efficacy of endoscopic hemoclipping using a transparent cap over the tip of the endoscope. PATIENTS AND METHODS: A total of 74 patients with a bleeding peptic ulcer or stigmata of recent hemorrhage underwent endoscopic hemoclipping. Technical difficulty in hemoclipping was experienced in 18 patients and the transparent cap was used in these cases. We therefore conducted a nonrandomized prospective study to compare bleeding control with the hemoclip with and without the aid of a transparent cap. RESULTS: There were no statistically significant differences between the patients treated with the cap and those treated without the cap with regard to the initial hemostasis rate (94.4 % vs. 91.1 %), the rebleeding rate (11.7 % vs. 11.8 %), or the permanent hemostasis rate (94.4 % vs. 96.4 %). CONCLUSIONS: Although there was no statistically significant difference between patients treated with or without a transparent cap, hemoclipping with the aid of the cap made it possible to clip a lesion too tangential to be clipped without it. However, this study did not compare conventional hemoclipping with hemoclipping using a cap because the cap was only used in cases in which conventional clipping had failed.

Duodenal Ulcer↗
PubMed2002

Neonatal Meishan pigs show POU1F1 genotype effects on plasma GH and PRL concentration.

Chinese Meishan pigs develop rapidly with onset of puberty at less than 100 days of age, and have a smaller placental size and larger litter size as compared with British/Continental breeds. POU1F1 is a member of the POU-domain family gene and is a positive regulator for growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone beta (TSHbeta) in several mammalian species. To investigate the role of POU1F1 in controlling pig growth and reproduction traits, Meishan (MS) pigs segregating a MspI POU1F1 polymorphism were used to determine differences of GH and PRL at both mRNA and circulating hormone concentrations. Animals from nine litters were used to collect pituitary (n=60) and/or blood samples (n=80) at day 0, 15, and 30 after birth, and all animals were genotyped (CC, CD, DD) for the MspI POU1F1 polymorphism. Reverse transcriptase-polymerase chain reaction (RT-PCR) with standard curve quantification was used to quantify mRNA levels for GH, PRL, and two alternative POU1F1 transcripts, POU1F1-alpha, and POU1F1-beta. Radioimmunoassays were done to determine the circulating concentration of GH and PRL in blood plasma. Our results indicated a significant effect of POU1F1 genotype on circulating levels of both GH and PRL at birth, but not thereafter. The DD neonates had lower levels of GH, but higher levels of PRL, than other genotypes. POU1F1-alpha mRNA decreased (P<0.05) from days 0 to 30, which paralleled decreases (P<0.05) in GH mRNA as well as PRL and GH plasma levels over the same period. POU1F1-beta mRNA levels did not significantly change over this period. Correlations were significant between POU1F1-alpha mRNA and both GH mRNA and GH plasma concentration levels, as well as between the two POU1F1 mRNA isoforms. Results from this study add to our understanding of the role of POU1F1 in controlling pig development and reproduction.

Aging↗
PubMed2002

Precise mapping of breakpoints in conserved synteny between human chromosome 1 and pig chromosomes 4, 6 and 9.

Previous comparative mapping suggested that at least five pig chromosomes (Sscr4, 6, 9, 10 and 14) share homology with human chromosome 1 (Hsap1). A significant quantitative trait loci (QTL) for fat deposition has been identified on Sscr4 that appears to be near the junction region between Sscr4 and Sscr9 relative to Hsap1. It is of interest to define the boundaries of conserved synteny between pig chromosomes and Hsap1 to use human map information to identify putative comparative positional candidates for this QTL. Eleven genes, including Janus kinase 1 (JAK1), Prostaglandin E receptor3 (PTGER3), urate oxidase (UOX), coagulation factor 3 (F3), vascular cell adhesion molecule 1 (VCAM1), ribosomal protein L5 (RPL5), POU domain, class 2, transcription factor 1 (POU2F1), coagulation factor 5 (F5), Prostaglandin endoperoxide synthase-2 (PTGS2), myosin binding protein H (MYBPH) and Antithrombin III (SERPINC1), were selected to refine the boundaries of the blocks of conserved synteny between Hsap1 and pig chromosomes. Pig sequence tagged sites (STSs) were developed and used to physically map these 11 genes using a somatic cell hybrid panel. Eight loci have been mapped by using fluorescent in situ hybridization (FISH) to improve map resolution. Heterologous FISH was used to refine the location of VCAM1 on human chromosomes. In addition, human yeast artificial chromosomes (YACs) were mapped by heterologous FISH on pig metaphases to refine the boundaries of the regions of homology between Sscr4 and Sscr9 on Hsap1. Results from this study suggest the precise break in conserved synteny on Hsap1 corresponding to the Sscr4/6 and Sscr4/9 transitions are most likely on the Hsap1p22 and Hsap1q24-25 regions, respectively. Further, our data predict that Hsap1q21-24 is a candidate region for the backfat QTL localized to Sscr4.

Animals↗
PubMed2002

Two cases of steakhouse syndrome associated with nutcracker esophagus.

The most common type of esophageal food-related foreign body is the meat bolus, which is frequently associated with underlying esophageal stenosis. Herein, we report two cases of meat bolus impaction associated with nutcracker esophagus. In the first case, the 63-year-old male patient had chest discomfort and swallowing difficulty after ingestion of butcher's meat. In the second case, the 55-year-old male patient had complained of swallowing difficulty after ingestion of chicken. In both cases, no pathologic findings were observed endoscopically after removal of the esophageal meat bolus. We performed esophageal manometry, which showed very high amplitudes of esophageal pressure in the mid- and distal esophagus. These findings were consistent with nutcracker esophagus. These cases show that esophageal motility disorder may be the cause of esophageal foreign body impaction, and esophageal manometry should be performed for evaluation of the cause of foreign body, especially in an endoscopically normal patient.

Deglutition Disorders↗
PubMed2001

Do denervated peripheral nerve trunks become ischemic? The impact of chronic denervation on vasa nervorum.

The long-term relationship between the peripheral nerve trunk and its vascular supply, the vasa nervorum, has not been considered in the context of denervation and regeneration. While the microvessels of peripheral nerve are not thought to influence Wallerian degeneration itself, in this work we explored how vasa nervorum respond to denervation of the nerve trunk. Our hypotheses were that the presence of axons had a significant impact on the vasa nervorum and that the absence of reinnervation might eventually lead to an unfavorable ischemic regenerative microenvironment. We studied rat sciatic nerve trunks for up to 6 months following transection and either prevented regeneration or allowed it to proceed. Vasa nervorum were studied in several ways: (i) measurements of local endoneurial blood flow using microelectrode hydrogen clearance polarography; (ii) measurements of erythrocyte flux (flow) in the extrinsic nerve plexus using laser Doppler flowmetry; (iii) India ink perfusion of microvessels in unfixed nerve; (iv) mRNA expression of vascular endothelial growth factor (VEGF) using reverse transcription polymerase chain reaction. Early after injury, there were rises in endoneurial and extrinsic flow, microvessel numbers, and VEGF mRNA expression. Angiogenesis was apparently confined to the epineurial and perineurial compartments. Later, however, there were substantial declines in flow observed in long-term (6-month) denervated sciatic nerve trunks associated with declines in the caliber of new microvessels. Reinnervated sciatic nerves had restored endoneurial blood flow. The findings confirm important relationships between axon presence and local blood flow. Angiogenesis is a feature of the injured peripheral nerve, but long term denervated nerve trunks have declines of flow despite retaining new microvessels.

Animals↗
PubMed2001

Detection of putative periodontal pathogens in non-insulin-dependent diabetes mellitus and non-diabetes mellitus by polymerase chain reaction.

It has been assumed that there is a relationship between periodontal diseases and diabetes mellitus, however the putative periodontal microorganisms in non-diabetes mellitus (non-DM) individuals and non-insulin-dependent diabetes mellitus (NIDDM) patients have not been well studied. In this study, the detection rates of 5 putative periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Eikenella corrodens, Treponema denticola, and Candida albicans by polymerase chain reaction (PCR) between NIDDM and non-DM adults were compared. A total of 246 adults were randomly recruited and periodontal parameters including: plaque index (P1I), gingival index (GI), probing depth (PD) and attachment level (AL) were recorded. Subgingival plaque samples were collected by sterile curettes from the most diseased and healthy sites based on PD and AL. The differences in periodontal parameters and microbiological data in healthy and diseased sites between non-DM and NIDDM patients were compared by chi-square analysis. The results showed no significant differences in age, gender, GI, P1I, PD, and prevalence of the 5 microorganisms between the NIDDM and the non-diabetic groups. However, except for A. actinomycetemcomitans, the prevalence of the periodontal microorganisms tested was significantly higher (p <0.001) in diseased sites than in the healthy sites in both groups. The P1I, GI, PD and AL were significantly higher in T. denticola positive sites than in negative sites. The results suggested that P. gingivalis, T. denticola, E. corrodens and C. albicans may play important roles in the periodontitis of both NIDDM and non-DM individuals, however the etiology of periodontitis in both groups may not be different from each other.

Adult↗