Biomedical subjects

Y C Wang

Publications and source records attributed to Y C Wang.

At least 37 records · Page 2Linked to original sources

PubMed2001

Allelic variants of the alpha1a adrenoceptor and the promoter region of the alpha2a adrenoceptor and temperament factors.

Human personality traits are partially determined by genes. It has been suggested that the reward-dependence dimension assessed by the Tridimensional Personality Questionnaire (TPQ) is related to the central noradrenergic system. Our population-based association study tested the hypothesis that genetic variants of the adrenoceptor are associated with this personality trait. The alpha1a- and the alpha2a-adrenoceptor genotypes were determined for 198 healthy Han Chinese who had completed the TPQ. We found no significant differences for TPQ personality-factor scores, including reward dependence and its subscales, for subjects showing different adrenoceptor genotypes. Our negative findings suggest that polymorphisms of the alpha1a adrenoceptor and of the promoter region of the alpha2a-adrenoceptor have no major effect on the reward-dependence personality trait as assessed by TPQ.

Adult↗

PubMed2001

A study of alpha-adrenoceptor gene polymorphisms and Alzheimer disease.

There exists considerable evidence implicating abnormalities of the alpha (alpha)-adrenergic system in the development of Alzheimer disease (AD). We propose to investigate potential correlations between the presence or otherwise of alpha-adrenoceptor polymorphisms and the presence of AD. We studied the polymorphisms of the alpha1a- and the alpha2a-adrenoceptor genes in 142 AD patients and 98 normal controls. The result demonstrated that none of the alpha2a-adrenoceptor genotypes was associated with increased susceptibility to AD. However, there was a trend that the frequency of the C allele of the alpha1a-adrenoceptor was elevated and an excess of the CC genotype (90.1%) was found in the subjects with AD in comparison with the controls (78.6%). This association was unrelated to the apolipoprotein E genotypes. The hypothesis that the alpha1a-adrenoceptor gene may be implicated in the pathogenesis of AD may deserve further study.

Aged↗

PubMed2001

Imaging columns of the light elements carbon, nitrogen and oxygen with sub Angstrom resolution.

It is reported that lattice imaging with a 300 kV field emission microscope in combination with numerical reconstruction procedures can be used to reach an interpretable resolution of about 80 pm for the first time. A retrieval of the electron exit wave from focal series allows for the resolution of single atomic columns of the light elements carbon, nitrogen, and oxygen at a projected nearest neighbor spacing down to 85 pm. Lens aberrations are corrected on-line during the experiment and by hardware such that resulting image distortions are below 80 pm. Consequently, the imaging can be aberration-free to this extent. The resolution enhancement results from increased electrical and mechanical stability of the instrument coupled with a low spherical aberration coefficient of 0.595 + 0.005 mm.

Journal Article↗

PubMed2001

Sub-Angstrom high-resolution transmission electron microscopy at 300 keV.

Sub-Angstrom transmission electron microscopy has been achieved at the National Center for Electron Microscopy (NCEM) by a one-Angstrom microscope (OAM) project using software and enhanced hardware developed within a Brite-Euram project (Ultramicroscopy 64 (1996) 1). The NCEM OAM provides materials scientists with transmission electron microscopy at a resolution better than 1 A by using extensive image reconstruction to exploit the significantly higher information limit of an FEG-TEM over its Scherzer resolution limit. Reconstruction methods chosen used off-axis holograms and focal series of underfocused images. Measured values of coherence parameters predict an information limit of 0.78 A. Images from a [1 1 0] diamond test specimen show that sub-Angstrom resolution of 0.89 A has been achieved with the OAM using focal series reconstruction.

Journal Article↗

PubMed2001

The DSmurf ubiquitin-protein ligase restricts BMP signaling spatially and temporally during Drosophila embryogenesis.

We identified Drosophila Smurf (DSmurf) as a negative regulator of signaling by the BMP2/4 ortholog DPP during embryonic dorsal-ventral patterning. DSmurf encodes a HECT domain ubiquitin-protein ligase, homologous to vertebrate Smurf1 and Smurf2, that binds the Smad1/5 ortholog MAD and likely promotes its proteolysis. The essential function of DSmurf is restricted to its action on the DPP pathway. DSmurf has two distinct, possibly mechanistically separate, functions in controlling DPP signaling. Prior to gastrulation, DSmurf mutations cause a spatial increase in the DPP gradient, as evidenced by ventrolateral expansion in expression domains of target genes representing all known signaling thresholds. After gastrulation, DSmurf mutations cause a temporal delay in downregulation of earlier DPP signals, resulting in a lethal defect in hindgut organogenesis.

Animals↗

PubMed2001

Phosphorylation of p90rsk during meiotic maturation and parthenogenetic activation of rat oocytes: correlation with MAP kinases.

This paper reports on the activation of p90rsk during meiotic maturation and the inactivation of p90rsk after electrical parthenogenetic activation of rat oocytes. In addition, the correlation between p90rsk and MAP kinases after different treatments was studied. We assessed p90rsk activity by examining its electrophoretic mobility shift on SDS-PAGE and evaluated ERK1+2 activity by both mobility shift and a specific antibody against phospho-MAP kinase. The phosphorylation of p90rsk during rat oocyte maturation was a sequential process that may be divided into two stages: the first stage was partial phosphorylation, which was irrelevant with MAP kinases because p90rsk phosphorylation took place prior to activation of MAP kinases. The second stage inferred full activation occurred at the time when MAP kinases began to be activated (3 h after germinal visicle breakdown). Evidence for the involvement of MAP kinases in the p90rsk phosphorylation was further obtained by the following approaches: (1) okadaic acid (OA) accelerated the phosphorylation of both MAP kinases and p90rsk; (2) OA induced phosphorylation of both MAP kinases and p90rsk in the presence of IBMX; (3) when activation of MAP kinases was inhibited by cycloheximide, p90rsk phosphorylation was also abolished; (4) dephosphorylation of p90rsk began to take place at 3 h post-activation, temporally correlated with the completion of MAP kinase inactivation; (5) phosphorylation of both kinases was maintained in oocytes that failed to form pronuclei after stimulation; (6) OA abolished the dephosphorylation of both kinases after parthenogenetic activation. Our data suggest that MAP kinases are not required for early partial activation of p90rsk but are required for full activation of p90rsk during rat oocyte maturation, and that p90rsk dephosphorylation occurs following MAP kinase inactivation after parthenogenetic activation of rat oocytes.

1-Methyl-3-isobutylxanthine↗

PubMed2001

Early genes responsive to abscisic acid during heterophyllous induction in Marsilea quadrifolia.

The aquatic fern Marsilea quadrifolia produces different types of leaves in response to changes in natural environment and culture conditions. When the conditions are in favor of producing the submerged-type leaves, exogenous application of the plant hormone abscisic acid (ABA) induces the formation of aerial-type leaves. Tissues responsive to ABA were localized to the shoot apical meristem and the associated organ primordia. From these tissues, at least two tiers of ABA-regulated early genes were identified, including seven primary genes and seventeen secondary genes. These genes, designated ABRH for ABA-responsive heterophylly, showed diverse expression patterns during the course of heterophyllous induction. Changes in the transcript level of ABRH genes started early, within 0.5-1.0 h after the addition of ABA to the culture medium. Some changes were transient while the others were persistent. The ABRHs contain extensive sequence homology to known genes, including those encoding transcription factors, protein kinases, membrane transporters, metabolic enzymes, structural proteins and those encoded by the chloroplast genome. Identification of these ABRHs is a first step toward the understanding of the regulation mechanisms of heterophylly, and the results suggest the involvement of novel metabolic and regulatory pathways in ABA-controlled morphogenesis.

Abscisic Acid↗

PubMed2001

Comparative study of platelet activation markers in diabetes mellitus patients complicated by cerebrovascular disease.

Cerebrovascular disease and other vascular diseases are common complications of non-insulin-dependent diabetes mellitus (NIDDM) and are associated with its increased morbidity and mortality. Platelet activation plays an important role in the pathomechanisms of these vascular diseases. Although several indices have been used to assess platelet activation, few data are available indicating which are more sensitive or more valuable in this situation. We have measured platelet arachidonic acid metabolites [thromboxane B2 (TXB2) and 11-dehydro-thromboxane B2 (TXB2)] and plasma P-selectin, platelet fibrinogen binding and membrane glycoproteins in 47 well-characterized NIDDM patients with cerebrovascular disease, 38 NIDDM patients without vascular diseases, and 36 age-matched healthy individuals. Our study shows that platelets were remarkably activated in NIDDM patients with cerebrovascular diseases. The measurement of plasma 11-dehydro-TXB2 and the determination of fibrinogen binding to, and P-selectin expression on platelets would reveal a higher diagnostic sensitivity for detecting in vivo platelet activation than other markers.

Adult↗

PubMed2001

A new mode of percutaneous upper thoracic phenol sympathicolysis: report of 50 cases.

OBJECTIVE: Our previous study demonstrated that a high concentration of phenol (75-90%) with minimal volume (0.02 ml) can elicit serious degeneration of ganglion cells of the stellate ganglia in cats. Another previous study in our clinical patients demonstrated that approximately 84 to 90% of the upper thoracic (T2-T3) sympathetic trunks can be found under an endoscope on the ventral side of the T2-T3 rib heads. In this report, we present a new mode of dorsal percutaneous thoracic phenol sympathicolysis (PTPS) for the treatment of palmar hyperhidrosis or axillary bromidrosis. METHODS: Fifty patients with palmar hyperhidrosis or axillary bromidrosis were injected with 75% phenol into a total of 98 sides of the T2-T3 or T3-T4 sympathetic trunks and ganglia. The injected volume was 0.6 to 1.2 ml (average, 0.8 ml) for each side. The technique of dorsal percutaneous injection was performed under local anesthesia or local with intravenous general anesthesia and under the guidance of a C-arm fluoroscope. RESULTS: Forty patients (80%) showed satisfactory results, including cessation of sweating. The success rates of PTPS were 83.7% (41 of 49 patients) on the left side and 91.8% (45 of 49 patients) on the right side. The skin temperature of the thumb increased by 5.3 to 5.4 degrees C approximately 1 hour after the phenol injection in patients with satisfactory results, whereas it increased by only 1.3 to 2.7 degrees C in patients who had unsatisfactory results. CONCLUSION: PTPS may be a good alternative to endoscopic sympathectomy to treat palmar hyperhidrosis and axillary bromidrosis. The skin temperature of the thumb is still a useful index to evaluate preliminarily whether PTPS has been successful.

Adolescent↗

PubMed2001

Estrogen receptor alpha gene polymorphism in schizophrenia: frequency, age at onset, symptomatology and prognosis.

Schizophrenic disorders are equally distributed for both sexes; however, later onset, milder psychopathology and better outcome are associated with the female gender. This sex difference is thought to be partly due to the estrogen system. Recent studies have determined that estrogen receptor alpha subtype (ER alpha) genetic polymorphisms may affect the expression of ER alpha, and are associated with Alzheimer's disease. For this study, we investigated the association of ER alpha polymorphisms for 125 schizophrenic patients and 142 control subjects. No significant differences for genotype distribution or allele frequency were revealed comparing controls and schizophrenic patients. The ER alpha genotypes were not associated with onset age, psychiatric symptoms or outcome for schizophrenic cases. With new research highlighting the prominent role of sex hormones in neurological and psychological dysfunction, further study is needed to explore the genetic effect of the sex hormone receptor gene on susceptibility mental disorders and associations with different phenotypes.

Adult↗

PubMed2001

Promoter-proximal regulatory elements involved in oriP-EBNA1-independent and -dependent activation of the Epstein-Barr virus C promoter in B-lymphoid cell lines.

The identification of the cellular factors that control the transcription regulatory activity of the Epstein-Barr virus C promoter (Cp) is fundamental to the understanding of the molecular mechanisms that control virus latent gene expression. Using transient transfection of reporter plasmids in group I phenotype B-lymphoid cells, we have previously shown that the -248 to -55 region (-248/-55 region) of Cp contains elements that are essential for oriPI-EBNA1-dependent as well as oriPI-EBNA1-independent activation of the promoter. We now establish the importance of this region by a detailed mutational analysis of reporter plasmids carrying Cp regulatory sequences together with or without oriPI. The reporter plasmids were transfected into group I phenotype Rael cells and group III phenotype cbc-Rael cells, and the Cp activity measured was correlated with the binding of candidate transcription factors in electrophoretic mobility shift assays and further assessed in cotransfection experiments. We show that the NF-Y transcription factor interacts with the previously identified CCAAT box in the -71/-63 Cp region (M. T. Puglielli, M. Woisetschlaeger, and S. H. Speck, J. Virol. 70:5758-5768, 1996). We also show that members of the C/EBP transcription factor family interact with a C/EBP consensus sequence in the -119/-112 region of Cp and that this interaction is important for promoter activity. A central finding is the identification of a GC-rich sequence in the -99/-91 Cp region that is essential for oriPI-EBNA1-independent as well as oriPI-EBNA1-dependent activity of the promoter. This region contains overlapping binding sites for Sp1 and Egr-1, and our results suggest that Sp1 is a positive and Egr-1 is a negative regulator of Cp activity. Furthermore, we demonstrate that a reporter plasmid that in addition to oriPI contains only the -111/+76 region of Cp still retains the ability to be activated by EBNA1.

B-Lymphocytes↗

PubMed2001

Polyamines: new cues in cellular signal transduction.

The naturally occurring polyamines putrescine, spermidine, and spermine are involved in signal transduction. This has been demonstrated by using inhibitors for polyamine biosynthesis (such as alpha-difluoromethylornithine) or adding polyamines to cultured cells. Different polyamines, preferentially activated protein kinases (tyrosine kinases and MAP kinases), stimulated the expression of nuclear protooncogenes (myc, jun, and fos).

Animals↗

PubMed2001

Genetic association analysis of alpha-1-antichymotrypsin polymorphism in Parkinson's disease.

alpha(1)-Antichymotrypsin (ACT) gene has been suggested as a susceptibility factor for Parkinson's disease (PD) and might be related to the onset of PD. We replicated these findings in a Chinese population. The results demonstrated that the ACT genotypic and allelic distributions showed no significant differences between the PD patient and the control groups. The age at onset was younger in the heterozygotes than in the homozygotes (p = 0.042). We suggest that the ACT polymorphism might play some role in the pathogenesis of PD, especially in the onset.

Age of Onset↗

PubMed2001

No association between tryptophan hydroxylase gene polymorphism and Alzheimer's disease.

Serotonergic dysfunction is implicated in Alzheimer's disease (AD) on the basis of studies of serotonin and its metabolite in postmortem specimens and CSF. There were also reports on association of a tryptophan hydroxylase (TPH) intron 7 variant and CSF 5-hydroxyindoleacetic acid concentrations. These suggested TPH might be a candidate to study for possible involvement in AD. Using a case-control association approach, we studied the TPH polymorphism in 150 subjects with AD and 100 controls. There were no significant differences in genotype or allele frequencies between controls and AD patients. The negative findings suggested that this TPH polymorphism has no major effect on the development of AD. However, the genetic variation of the TPH gene related to the symptomatology of AD deserves further investigation.

Aged↗

PubMed2001

Association analysis of a functional catechol-o-methyltransferase gene polymorphism in schizophrenic patients in Taiwan.

The catechol-O-methyltransferase (COMT) gene was thought to be a candidate gene for schizophrenia because of its role in inactivating dopamine. This study examined the relationship between a functional polymorphism (val158met) of the COMT gene, schizophrenia and its associated behaviors. One hundred and ninety-eight Chinese schizophrenic patients and 188 controls were genotyped by polymerase chain reaction restriction fragment length polymorphism. Of the schizophrenic patients, 72 had a history of violence and 62 had a history of suicide attempts. The results failed to show significant association between val158met polymorphism and schizophrenia, violence or suicide. However, our results showed a significant difference in age at disease onset among different genotypes (F = 5.501, p = 0.005).

Adult↗

PubMed2001

Serotonin 6 receptor polymorphism in schizophrenia: frequency, age at onset and cognitive function.

The relative abundance of serotonin 6 receptor (5HT6) in some limbic regions and the high affinity of some antipsychotics for 5HT6 suggest that the 5HT6 gene might play a role in the pathogenesis of schizophrenic disorders. A recent study reported an association between a C267T polymorphism of the 5HT6 gene and schizophrenia. In order to test whether the 5HT6 gene plays a role in the pathogenesis of schizophrenic disorders, patients (n = 148) and control subjects (n = 160) were genotyped for 5HT6. We also investigated the relationship between genotypes and patients' age at onset and cognitive function in schizophrenic patients. Cognitive function in the patients was evaluated by the Mini-Mental State Examination (MMSE). The results demonstrated no significant differences in genotype or allele frequencies between controls and patients. In the patient group, age at onset and MMSE score did not differ significantly among the three 5HT6 genotpyes. The results of this study suggest that the 5HT6 C267T polymorphism plays no major role in susceptibility to the development of schizophrenia and is not related to cognitive impairment or age at onset in schizophrenic patients. Further studies of the relation between 5HT6 polymorphism and the symptoms and the therapeutic response in schizophrenic patients may help to elucidate the role of 5HT6 in the pathogenesis of schizophrenia.

Adult↗

PubMed2001

Association study of angiotensin-converting enzyme gene polymorphism with schizophrenia and polydipsia.

Angiotensin-converting enzyme (ACE) is a key enzyme in the renin-angiotensin system and can modulate dopamine turnover in the midbrain. Previous studies have revealed changes in the central ACE levels for schizophrenic patients, possibly related to the polydipsia commonly demonstrated for chronic schizophrenia. An insertion (I)/deletion (D) polymorphism of the ACE gene has been associated with ACE levels. Therefore, we elected to investigate the ACE I/D polymorphism for 124 schizophrenic patients and 117 control subjects. No significant differences for the genotype distribution or the allele frequency were revealed comparing controls and schizophrenic patients. The ACE genotypes were not associated with onset age or psychiatric symptoms for the schizophrenic cases. A modest association was revealed for this ACE polymorphism and polydipsia diagnosis for these patients. Using bearers of the D allele as baseline, the ratio for I/I homozygote was 2.31 (95% CI 0.95-5.65). This association needs further replication as it may have implications for the pathogenesis and the treatment of polydipsia for schizophrenic patients.

Adult↗

PubMed2001

Endoscope-assisted microsurgery for treatment of a suprasellar craniopharyngioma presenting precocious puberty.

Being the most common childhood tumor to involve the hypothalamus and pituitary gland, craniopharyngioma, a histologically benign tumor, is usually related to growth retardation and hypogonadism. The presentation of precocious puberty is very rare for a hypothalamic craniopharyngioma. Here, we report such a case. The female patient had presented with symptoms of menarche and breast development since she was 6 years old. Hormonal therapy with a gonadotropin-releasing hormone analogue was instituted to cease precocious puberty but was unsuccessful. Magnetic resonance imaging of the sella showed a 1-cm tumor in the hypothalamic area. Through a pterional approach, the tumor was removed en bloc with endoscope-assisted microsurgery. After the operation, our patient's symptoms improved, so the hormone therapy was discontinued. This extremely unique association of craniopharyngioma and precocious puberty, the causes and mechanisms involved along with the advantages of endoscope-assisted microsurgery are discussed.

Child↗