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Biomedical subjects

Y S Yang

Publications and source records attributed to Y S Yang.

At least 73 records · Page 4Linked to original sources

The consistency and reliability of periodontal bone level measurements using digital scanning radiographic image analysis--a pilot study.

The purpose of the present study was to evaluate the consistency and reliability of alveolar bone height measurement using digital scanning radiographic image analysis (DSRIA). A randomly selected (standardized paralleling technique) periapical radiographs of 20 molar teeth (10 maxillary molars and 10 mandibular molars) from 178 individuals with periodontitis were reporting or referred to the patient population of the dental clinics of the teaching hospital. Radiographic measurements were performed and read by two examiners, with a separation time of three weeks of different tooth groups and as established by double reading of 20 molar teeth in 10 individuals using the DSRIA. The calculating data of radiographic alveolar bone loss (RABL) measured and analyzed by the DSRIA for each molar group were compared based on the inter- and intra-examiners' data. The means and standard deviations were calculated to compare radiographs of the inter- and intra-examiners' groups. The reliability coefficients were computed to assess the consistency and reliability for each molar group. The results revealed that the intra- and inter-examiners' reliability coefficients ranged from 0.986 to 0.995 (p < 0.001, significantly different from 0). An excellent reproducibility was indicated in maxillary molar, mandibular molar and of both arches, respectively. It was concluded that the standard periapical radiograph using the DSRIA has the potential to be a valuable and reliable method in measuring linear alveolar bone defects caused by periodontitis.

Adult↗

[The application of multi-pulse stripping amperometric detection to capillary electrophoresis].

There are some drawbacks in amperometric detection in capillary electrophoresis since there is influence of high voltage from electrophoretic instrument. Three electrodes of electrochemical detection system and electrochemical system of capillary electrophoresis are separately placed in capillary outlet buffer reservoir, which can lead to a reduction in the influence of high voltage in the great degree. A carbon fiber with diameter of 7 microns is used as working electrode, and placed just at the separation capillary outlet. The multi-pulse stripping amperometric detection has 1.1 s deposition step and several stripping steps with 0.02 s, which can increase the detection amperometric current and identify the species of each separated component in some classes by different pulse stripping potentials. This detection technique was applied in the separation of Cu, Zn, Pb, Tl and Cd of 25 mg/L by the capillary electrophoresis, and separation efficiency is over 60 thousands theoretical plates. The limit of the multi-pulse stripping amperometry detection was 0.10 microgram/L for cadmium by using water plug field amplified injection.

Carbon↗

Rational engineering of a miniprotein that reproduces the core of the CD4 site interacting with HIV-1 envelope glycoprotein.

Protein-protein interacting surfaces are usually large and intricate, making the rational design of small mimetics of these interfaces a daunting problem. On the basis of a structural similarity between the CDR2-like loop of CD4 and the beta-hairpin region of a short scorpion toxin, scyllatoxin, we transferred the side chains of nine residues of CD4, central in the binding to HIV-1 envelope glycoprotein (gp120), to a structurally homologous region of the scorpion toxin scaffold. In competition experiments, the resulting 27-amino acid miniprotein inhibited binding of CD4 to gp120 with a 40 microM IC(50). Structural analysis by NMR showed that both the backbone of the chimeric beta-hairpin and the introduced side chains adopted conformations similar to those of the parent CD4. Systematic single mutations suggested that most CD4 residues from the CDR2-like loop were reproduced in the miniprotein, including the critical Phe-43. The structural and functional analysis performed suggested five additional mutations that, once incorporated in the miniprotein, increased its affinity for gp120 by 100-fold to an IC(50) of 0.1-1.0 microM, depending on viral strains. The resulting mini-CD4 inhibited infection of CD4(+) cells by different virus isolates. Thus, core regions of large protein-protein interfaces can be reproduced in miniprotein scaffolds, offering possibilities for the development of inhibitors of protein-protein interactions that may represent useful tools in biology and in drug discovery.

Amino Acid Motifs↗

A human immunoglobulin (Ig)A calpha3 domain motif directs polymeric Ig receptor-mediated secretion.

Polymeric immunoglobulins provide immunological protection at mucosal surfaces to which they are specifically transported by the polymeric immunoglobulin receptor (pIgR). Using a panel of human IgA1/IgG1 constant region "domain swap" mutants, the binding site for the pIgR on dimeric IgA (dIgA) was localized to the Calpha3 domain. Selection of random peptides for pIgR binding and comparison with the IgA sequence suggested amino acids 402-410 (QEPSQGTTT), in a predicted exposed loop of the Calpha3 domain, as a potential binding site. Alanine substitution of two groups of amino acids in this area abrogated the binding of dIgA to pIgR, whereas adjacent substitutions in a beta-strand immediately NH2-terminal to this loop had no effect. All pIgR binding IgA sequences contain a conserved three amino acid insertion, not present in IgG, at this position. These data localize the pIgR binding site on dimeric human IgA to this loop structure in the Calpha3 domain, which directs mucosal secretion of polymeric antibodies. We propose that it may be possible to use a pIgR binding motif to deliver antigen-specific dIgA and small-molecule drugs to mucosal epithelia for therapy.

Amino Acid Sequence↗

Transmission of de novo mutations of the deleted in azoospermia genes from a severely oligozoospermic male to a son via intracytoplasmic sperm injection.

OBJECTIVE: To investigate the transmission of microdeletions in the deleted in azoospermia (DAZ) genes to a male offspring via intracytoplasmic sperm injection (ICSI). DESIGN: Case report. SETTING: Reproductive unit of a university teaching hospital. PATIENT(S): A 29-year-old, severely oligozoospermic male with microdeletions of the DAZ genes in Yq interval 6 and his son, who was conceived via ICSI. INTERVENTION(S): DNA screening for the microdeletions in Yq interval 6 with 24 sequence tagged sites with the use of polymerase chain reaction amplification for the patient, the patient's father, and the patient's son. Paternity identification was performed using nine hypervariable short tandem repeats. MAIN OUTCOME MEASURE(S): Deletion mapping of Yq interval 6 from sequence tagged sites and electropherogram of short tandem repeats for DNA fingerprinting. RESULT(S): The son had the same microdeletions of the DAZ genes as the patient, and the patient's father had normal DAZ genes. The paternity of the patient, the patient's father, and the patient's son was verified. CONCLUSION(S): De novo DAZ microdeletions in an infertile male can be transmitted to a male offspring via ICSI. DNA screening tests for DAZ genes before ICSI may help in the genetic counseling of patients with idiopathic azoospermia or severe oligozoospermia.

Adult↗

Prognostic importance of serial cytokine changes in ascites and pleural effusion in women with severe ovarian hyperstimulation syndrome.

OBJECTIVE: To determine the prognostic value of various cytokine levels in ascites and pleural effusion during the evolution of severe ovarian hyperstimulation syndrome (OHSS). DESIGN: A longitudinal study. SETTING: University teaching hospital. PATIENT(S): Twenty patients with severe OHSS who required either paracentesis or thoracentesis or both from whom ascites (n = 56) or pleural effusion (n = 12) samples were obtained. Control peritoneal fluid was obtained from 20 patients undergoing ovarian stimulation for IVF. INTERVENTION(S): Abdominal paracentesis for tense ascites and thoracentesis for massive pleural effusion. Control peritoneal fluid was obtained before oocyte retrieval. MAIN OUTCOME MEASURE(S): Levels of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), E2, and progesterone concentrations in ascites and pleural effusion. RESULT(S): Levels of VEGF and IL-6 in ascites dropped significantly during the course of OHSS and were not correlated with E2 concentrations. Levels of VEGF were significantly correlated with levels of IL-1 beta, IL-8, and TNF-alpha, as well as progesterone concentrations, hematocrit, and white blood cell counts. None of the cytokine levels measured in pleural effusion were correlated with the course of OHSS. CONCLUSION(S): These results suggest that local cytokines might be involved in the evolution of severe OHSS and possibly serve as prognostic markers for this syndrome.

Adult↗

Expression of leukemia inhibitory factor and its receptor in preimplantation embryos.

OBJECTIVE: To examine the expression of leukemia inhibitory factor (LIF) and its receptor (LIF-R) transcripts in human and murine preimplantation embryos. DESIGN: Prospective study. SETTING: University medical center. PATIENT(S): Human oocytes were obtained from patients undergoing IVF treatment. Two-cell murine embryos were obtained from ICR strain mice. INTERVENTION(S): Second-day intracytoplasmic sperm injection procedures were performed on oocytes that failed to be fertilized by IVF. Embryos were cultured to various stages and collected for study. MAIN OUTCOME MEASURE(S): The transcript levels of LIF and LIF-R in these embryos were examined and semiquantitated using single-cell reverse transcription-polymerase chain reaction methodology. RESULT(S): Leukemia inhibitory factor and LIF-R transcripts were detectable in most human preimplantation embryos (30 of 34 and 31 of 34 embryos showed LIF and LIF-R messenger RNA, respectively). There was a trend toward decreased expression of both transcripts in embryos at the four-cell stage and in embryos in which growth had been arrested for 24-48 hours. The expression of LIF and LIF-R genes in murine embryos was inconsistent. CONCLUSION(S): Preimplantation human embryos express LIF and LIF-R messenger RNA. It is suggested that LIF may be able to affect embryo development through its action at stages before implantation in an autocrine or paracrine manner.

Animals↗

The expression of killer cell inhibitory receptors on natural killer cells and activation status of CD4+ and CD8+ T cells in the decidua of normal and abnormal early pregnancies.

The establishment of the human placenta in early pregnancy is characterized by the presence of large numbers of natural killer cells within the maternal decidua. These NK cells have an unusual phenotype, CD3- CD16- CD56(bright), distinguishing them from peripheral blood NK cells. They may control trophoblast migration and placentation. Using a panel of monoclonal antibodies to several members of the KIR family and flow cytometry, we found that KIRs are expressed on decidual NK cells. There is variation in both the percentage of cells expressing a particular receptor and the density of receptor expression between decidual NK cells from different individuals. In anembryonic pregnancy, the proportions of decidual NK cells with a particular KIRs (GL183 and EB6) decreased significantly when compared with normal pregnancy (p = 0.01 and 0.01, respectively), raising the possibility that these NK receptors may be involved in recognition of the allogeneic fetus by the mother at the implantation site. In the decidua, more CD4+ and CD8+ T cells expressed CD69 and HLA-DR than in blood, indicating that T cells are regionally activated during early pregnancy. When compared with normal pregnancy, decidual HLA-DR+CD4+CD3+, CD69+CD8+CD3+ and HLA-DR+CD8+CD3+ T lymphocytes are significantly increased in anembryonic pregnancy. The over-activation of decidual T cells during anembryonic pregnancy may thus contribute to the increased NK cytotoxicity activity.

Antigens, CD↗

Serum concentration of the soluble interleukin-2 receptor in vitiligo patients.

Serum levels of sIL-2R can be used to monitor in vivo immune activation and its elevation have been shown to be correlated with T cell mediated immune disease such as atopic dermatitis, psoriasis, lymphoma and systemic sclerosis. Vitiligo is the disease of depigmentation caused by destruction of melanocytes, and there have been extensive studies on the immune pathogenesis. If the pathogenesis of vitiligo is correlated with the activation of T lymphocytes, the change of IL-2R will be detected compared with that of normal control. Therefore we sought the change in sIL-2R to determine whether T lymphocytes from patients with vitiligo show abnormal biological behavior. The quantitation of sIL-2R was done by sandwich enzyme-linked immunosorbent assay (ELISA) from the sera of 79 vitiligo patients and 40 normal controls. The results were summarized as following. The sIL-2R level in vitiligo patients (671.91 +/- 368.59 U/ml) was significantly increased compared with that of controls (370.8 +/- 71.8 U/ml; P < 0.005). According to clinical types, sIL-2R level in focal type of vitiligo patients was significantly higher than those in other types (segmental or generalized; P < 0.05). The sIL-2R level in patients less than 1 year duration was significantly higher than in patients more than 1 year duration (P < 0.05). The sIL-2R levels were not significantly different between active and inactive group. There was no significant differences among sIL-2R levels according to sex or age of onset. Our study showed that sIL-2R level was higher in vitiligo patients compared with that of normal controls, so the activation of T lymphocytes would be an important component in the pathogenesis of vitiligo. The higher sIL-2R levels in recent onset group would suggest that sIL-2R level might be an acute immunologic marker in vitiligo patients.

Adolescent↗

Management of foreign bodies in the gastrointestinal tract: an analysis of 104 cases in children.

BACKGROUND AND STUDY AIMS: Ingested foreign bodies may be managed by endoscopy, observation, or surgery. The aim of the study was to investigate the methods of removal of foreign bodies according to type and location, success rates, and complications. PATIENTS AND METHODS: The charts of 104 children who had ingested foreign bodies were retrospectively reviewed. RESULTS: Of the patients, 80 (76.9%) were managed endoscopically. The overall success rate for endoscopic management was 98.8%. There were no complications during endoscopic interventions. In 23 cases the foreign bodies spontaneously passed through the gastrointestinal tract (22.1%). Surgical removal of a foreign body was done in only one case (0.96%). The majority of the foreign bodies which were located in the upper gastrointestinal tract could be removed endoscopically regardless of the nature of the material. Foreign bodies in the small and large intestine tended to pass through spontaneously without complications. CONCLUSIONS: It appears that the endoscopic approach is the preferable method for the extraction of upper gastrointestinal foreign bodies in child patients because of its high success rate, and that foreign bodies in the small and large intestine tend to be passed spontaneously without complications.

Adolescent↗

Association of endometrial blood flow as determined by a modified colour Doppler technique with subsequent outcome of in-vitro fertilization.

An endometrial thickness of 10 mm or more has been reported to be favourable for embryo implantation. Nevertheless, many women participating in in-vitro fertilization (IVF) programmes have adequate endometrial thickness but do not achieve satisfactory implantation. With the aid of power Doppler sonography, we examined the association between intra-endometrial vascularity and reproductive outcome. For this study, we enrolled only women with endometrial thickness >/=ISOdia>/=10 mm and excluded those with apparent endometrial pathologies. Of 95 women undergoing IVF cycles, there resulted 37 intrauterine pregnancies. The women were of similar age, body mass index, peak oestradiol concentration and endometrial thickness, and a similar number of embryos were transferred. Those women with an intra-endometrial power Doppler area (EPDA) <5 mm2 achieved a significantly lower pregnancy rate (23. 5 versus 47.5%, P = 0.021) and implantation rate (8.1 versus 20.2%, P = 0.003) than those with an EPDA >/=ISOdia>/=5 mm2. We conclude that, in addition to endometrial thickness, EPDA may serve as a factor indicative of endometrial receptivity. Women with adequate endometrial thickness but a small EPDA tended to have an unfavourable reproductive outcome.

Adult↗

Increase in the production of interleukin-6, interleukin-10, and interleukin-12 by lipopolysaccharide-stimulated peritoneal macrophages from women with endometriosis.

PROBLEM: To verify whether the peritoneal macrophage (PM) is activated in endometriosis. METHOD OF STUDY: We examined the synthesis of nitric oxide (NO), total antioxidant, interleukin (IL)-6, IL-10, and IL-12 by cultured PMs, which were either unstimulated or stimulated with lipopolysaccharide (LPS), from women with endometriosis (early, n = 12; advanced, n = 11) or without endometriosis (n = 13). RESULTS: After stimulation with 2 ng/mL LPS for 24 hr, PMs from women with early-stage endometriosis secreted more NO, IL-6, and IL-10 than the controls. Higher IL-12 levels were noted in women with advanced endometriosis when compared with the controls. After 2 ng/mL-LPS stimulation for 24 hr, we also detected higher total antioxidant levels in the advanced-endometriosis group than those in the early-endometriosis group. CONCLUSION: The increased production of IL-6, IL-10, and IL-12 by stimulated PMs confirmed previous observations that the PM is the principle source of these cytokines in peritoneal fluid.

Endometriosis↗

Wide-angle fluorescein angiographic scanning with high resolution using a scanning laser ophthalmoscope through a mirror image fixation target.

Internal and moving targets of scanning laser ophthalmoscopes are not capable of observing the fundus beyond a field of more than 80 degrees with high resolution. The authors enabled wide-angle fundus examination with high resolution through a modification of the target. Mirror image fixation targets(MIFT), which fixated the opposite side of the examined eye onto the mirror image of five lamps placed 1.5 m away from the patient, were used to observe the fundus during fluorescein angiography in five diabetic retinopathy patients. In three of them, the ranges of the fundus examinations were measured using conventional internal fixation targets. The mean ranges of the fundus examinations when using MIFT (77.2 +/- 2.5 degrees horizontally, 67.9 +/- 2.1 degrees vertically) were significantly wider than when using internal fixation targets (65.5 +/- 2.6 degrees horizontally, 44.4 +/- 2.8 degrees vertically). MIFT provided a wide angle fundus view with high resolution equal to that of 40 degrees angle images using a scanning laser ophthalmoscope.

Diabetic Retinopathy↗

Fertilization capability of frozen epididymal sperm for intracytoplasmic sperm injection.

Both microsurgical epididymal sperm aspiration (MESA) and intracytoplasmic sperm injection (ICSI) are great advances in assisted reproductive techniques. By using the ICSI technique, frozen sperm from the epididymis can result in successful fertilization. The epididymal sperm retrieved via MESA can be cryopreserved for an in-vitro fertilization (IVF) procedure, thus, making repeat surgical retrieval of sperm unnecessary. We report a retrospective analysis of 24 ICSI cycles in 16 patients with obstructive or nonreconstructable azoospermia. Fresh epididymal sperm was used in 13 ICSI cycles and frozen-thawed epididymal sperm was used in the other 11. We compared the fertilization capability of ICSI using frozen-thawed epididymal sperm with fresh epididymal sperm. Eleven patients became pregnant and five of these pregnancies resulted from frozen epididymal sperm. The fertilization rate per oocyte was 58% with fresh sperm, and 66% with frozen-thawed sperm. The rate of clinical pregnancy for one embryo transfer was 46% with fresh sperm, and 45% with frozen-thawed sperm. There were no significant differences between fresh and frozen-thawed spermatozoa in the fertilization rate of oocytes or the clinical pregnancy rate. Our results suggest that we should cryopreserve supernumerary spermatozoa during a MESA/ICSI procedure in order to avoid repeated scrotal surgery.

Adult↗

Antimycoplasmal activities of (S)-(-)-9-fluoro-2,3-dihydro-3-methyl-10 -[4-(2-pyridyl)-1-piperazinyl]-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine -6-carboxylic acid (YH-6) in comparison with other antibiotics in vitro.

AIM: To determine the susceptibilities of Mycoplasma and Ureaplasma to (S)-(-)-9-fluoro-2,3-dihydro-3-methyl-10 -[4-(2-pyridyl)-1-piperazinyl]-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine -6-carboxylic acid (YH-6) and to compare it with those referential quinolones, macrolides, and tetracyclines. METHODS: The minimum inhibitory concentration (MIC) were determined by microdilution method in vitro. RESULTS: The MIC of YH-6 for Ureaplasma urealyticum (Uu: 250 micrograms.L-1), Mycoplasma hominis (Mh: 500 micrograms.L-1), M orale (Mo: 125 micrograms.L-1) and M salivarium (Ms: 125 micrograms.L-1) were closely similar to those of macrolides (erythromycin and leucomycin) and were 2-8 folds greater than those of ofloxacin (Ofl). Uu and Mh easily induced resistance to erythromycin and tetracycline. They did not easily form resistance to quinolone (YH-6, Ofl), josamycin and tylosin. Tetracycline-resistance (Tcr) or erythromycin-resistance (EMr) strains of Uu (or Mh) had cross-resistance to erythromycin or tetracycline. However, they had no cross-resistance to quinolone, josamycin and tylosin. CONCLUSION: YH-6 was a highly active quinolone against Mycoplasma, but could hardly induce resistance to Uu. EMr- or Tcr- strains of Uu (or Mh) had no cross-resistance to YH-6.

Anti-Bacterial Agents↗

Colorimetric determination of the purity of 3'-phospho adenosine 5'-phosphosulfate and natural abundance of 3'-phospho adenosine 5'-phosphate at picomole quantities.

This work presents novel colorimetric methods not only to measure 3'-phospho adenosine 5'-phosphate (PAP) and 3'-phospho adenosine 5'-phosphosulfate (PAPS) in the range of picomoles, but also to determine the purity of PAPS or PAP contaminants in PAPS in the range of nanomoles. These methods exploit the availability of overexpressed phenol sulfotransferase (PST) and the fact that sulfuryl group transfer requires the use of PAP or PAPS as a cofactor or cosubstrate. Experimental results indicate that absorption at 400 nm due to the production of 4-nitrophenol (pNP) is catalyzed by PST when the sulfuryl group transfers from 4-nitrophenylsulfate (pNPS) to PAP or to 2-napthol. In the absence of an acceptor substrate, PAPS is hydrolyzed to PAP by PST and is determined by sulfation with pNPS before and after this reaction. The change of absorption of pNP at 400 nm corresponds to the amount of PAP that is hydrolyzed from PAPS. Moreover, a standard curve is constructed using authentic PAP and PAP-free PST. Furthermore, this curve is used to determine the amount of PAP in extracts of pig liver, rat liver, and Escherichia coli.

Adenosine Diphosphate↗

Effects of 3'-phosphoadenosine 5'-phosphate on the activity and folding of phenol sulfotransferase.

Known spectroscopic and kinetic data are used to formulate pathways of the physiological and transfer reactions and the substrate inhibition of phenol sulfotransferase. Kinetic mechanisms indicate that release of PAP from enzyme complex is required for the physiological reaction but not for the transfer reaction. The pathways explain rate difference between the physiological and transfer reactions since the release of PAP is the rate-limiting step of the former reaction. Two enzyme species of phenol sulfotransferase which distinguish the physiological and transfer reaction were found to involve the binding of PAP. Differences between two forms of phenol sulfotransferase, alpha and beta, indicate that they assemble through different folding process. It is demonstrated that only alpha enzyme renatures in the presence of PAP and beta enzyme renatures only in the absence of PAP in vitro. In the over-expressed system, formation of alpha and beta phenol sulfotransferase is also dependent on the availability of PAP in Escherichia coli. It is concluded that folding of phenol sulfotransferase is assisted by PAP to form alpha enzyme. In the absence of PAP, beta form of phenol sulfotransferase is produced.

Animals↗

Crystal structure of p14TCL1, an oncogene product involved in T-cell prolymphocytic leukemia, reveals a novel beta-barrel topology.

BACKGROUND: Chromosome rearrangements are frequently involved in the generation of hematopoietic tumors. One type of T-cell leukemia, T-cell prolymphocytic leukemia, is consistently associated with chromosome rearrangements characterized by the juxtaposition of the TCRA locus on chromosome 14q11 and either the TCL1 gene on 14q32.1 or the MTCP1 gene on Xq28. The TCL1 gene is preferentially expressed in cells of early lymphoid lineage; its product is a 14 kDa protein (p14TCL1), expressed in the cytoplasm. p14TCL1 has strong sequence similarity with one product of the MTCP1 gene, p13MTCP1 (41% identical and 61% similar). The functions of the TCL1 and MTCP1 genes are not known yet. They have no sequence similarity to any other published sequence, including those of well-documented oncogene families responsible for leukemia. In order to gain a more fundamental insight into the role of this particular class of oncogenes, we have determined the three-dimensional structure of p14TCL1. RESULTS: The crystal structure of p14TCL1 has been determined at 2.5 A resolution. The structure was solved by molecular replacement using the solution structure of p13MTCP1, revealing p14TCL1 to be an all-beta protein consisting of an eight-stranded antiparallel beta barrel with a novel topology. The barrel consists of two four-stranded beta-meander motifs, related by a twofold axis and connected by a long loop. This internal pseudo-twofold symmetry was not expected on basis of the sequence alone, but structure-based sequence analysis of the two motifs shows that they are related. The structures of p13MTCP1 and p14TCL1 are very similar, diverging only in regions that are either flexible and/or involved in crystal packing. p14TCL1 forms a tight crystallographic dimer, probably corresponding to the 28 kDa species identified in solution by gel filtration experiments. CONCLUSIONS: Structural similarities between p14TCL1 and p13MTCP1 suggest that their (unknown) function may be analogous. This is confirmed by the fact that these proteins are implicated in analogous diseases. Their structure does not show similarity to other oncoproteins of known structure, confirming their classification as a novel class of oncoproteins.

Amino Acid Sequence↗