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Biomedical subjects

H J Yang

Publications and source records attributed to H J Yang.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of dialysis modalities on gastric myoelectrical activity in end-stage renal disease patients.

Gastric motility is controlled by gastric myoelectrical activity, which propagates from the proximal body to the distal antrum at a frequency of 3 cycles/min. In uremic patients, dyspeptic symptoms are common. To investigate whether dialysis modality affects gastric myoelectrical activity in uremic patients, we performed electrogastrography (EGG) in 41 patients without diabetes with end-stage renal disease (ESRD) undergoing hemodialysis (HD; n = 22) and continuous ambulatory peritoneal dialysis (CAPD; n = 19). EGG was performed noninvasively using abdominal surface electrodes in the fasting state before and 4 hours after HD and at empty and 2 hours after CAPD with 2,000 mL of dialysate. There were no significant differences in age, sex, body weight, duration of dialysis, and percentage of patients with upper gastrointestinal (UGI) symptoms (63.6% versus 42.1%). CAPD patients had significantly lower serum albumin levels (3.4 +/- 0.4 versus 3.9 +/- 0.4 g/dL; P < 0.05), greater serum total-cholesterol levels (189 +/- 33 versus 157 +/- 36 mg/dL; P: < 0.05), and greater percentages of patient with early satiety (42.1% versus 13.6%; P < 0.05) than HD patients. Dominant power significantly increased after HD (251.3 +/- 157.5 versus 512.9 +/- 390.0 dB; P < 0.05) but seemed to decrease after CAPD without statistical significance (416.2 +/- 323.6 versus 283.8 +/- 280.7 dB). There was no difference in the normal slow-wave frequency (NSWF) between HD and CAPD patients (predialysis, 60.7% +/- 29.3% versus 52.2% +/- 36.7%; postdialysis, 56.3% +/- 32.0% versus 50.9% +/- 34.2%). Tachygastria significantly increased after CAPD (pre-CAPD, 2.35% +/- 4.3% versus post-CAPD, 10.0% +/- 14.8%; P < 0.05). There was a significant correlation between changes in tachygastria after CAPD and grade of early satiety in CAPD patients with UGI symptoms (r = 0.74; P: < 0.05). Changes in NSWF after CAPD significantly correlated with age (r = -0.51; P: < 0.05). In conclusion, dialysis modalities seem to have different effects on gastric myoelectrical activity in patients with ESRD.

Female↗
PubMed2000

Performance on the Wisconsin Card Sorting Test among adolescents in Taiwan: norms, factorial structure, and relation to schizotypy.

The aims of this study were to assess developmental trends in performance on the Wisconsin Card Sorting Test (WCST) among 817 randomly selected adolescents aged 13-15 years, and to explore WCST performance factor structure and relationship to schizotypy. The results showed that of the nine WCST indexes, only the Categories Achieved and Failure to Maintain Set scores were associated with age, and only the Learning to Learn scores reached adult levels. Factor analysis of WCST performance scores yielded a three-factor structure. Psychometrically defined schizotypic subjects did not perform significantly worse than control subjects on any WCST indexes. These findings suggest that performance on various WCST indexes might indicate developmental changes at different ages, and deficits in WCST performance might not be sensitive indicators of vulnerability to schizophrenia in adolescence.

Adolescent↗
PubMed2000

Competence and behavioral/emotional problems among Taiwanese adolescents as reported by parents and teachers.

OBJECTIVE: To investigate competence and behavioral/emotional problems among nonreferred adolescents in Taiwan, using a Chinese version of the Child Behavior Checklist (CBCL-C) and the Teacher's Report Form (TRF-C). The psychometric properties of these instruments and cross-cultural differences were also examined. METHOD: Parents of 854 junior high school students aged 12 to 16 years in Taipei, Taiwan, were asked to complete the CBCL-C. Among these students, 162 had their teachers' ratings of the TRF-C. RESULTS: The internal consistency and 1-month test-retest reliability were satisfactory for both the CBCL-C and TRF-C, which were moderately correlated. Both exploratory and confirmatory factor analysis provided some support for the validity of Achenbach's cross-informant model. Parents' reports showed that compared with their American counterparts, Taiwanese adolescents tended to have lower scores on most competence scales, higher scores on scales that reflect covert behavior problems, and lower scores on scales that reflect more overt behavior problems. However, teachers' reports showed no significant differences on most competence and behavior problem scales. CONCLUSION: The CBCL-C and TRF-C are useful tools for assessing the mental health status of Taiwanese adolescents. The cross-cultural differences in adolescent behavior problems are discussed.

Achievement↗
PubMed2000

The common nodulation genes of Astragalus sinicus rhizobia are conserved despite chromosomal diversity.

The nodulation genes of Mesorhizobium sp. (Astragalus sinicus) strain 7653R were cloned by functional complementation of Sinorhizobium meliloti nod mutants. The common nod genes, nodD, nodA, and nodBC, were identified by heterologous hybridization and sequence analysis. The nodA gene was found to be separated from nodBC by approximately 22 kb and was divergently transcribed. The 2. 0-kb nodDBC region was amplified by PCR from 24 rhizobial strains nodulating A. sinicus, which represented different chromosomal genotypes and geographic origins. No polymorphism was found in the size of PCR products, suggesting that the separation of nodA from nodBC is a common feature of A. sinicus rhizobia. Sequence analysis of the PCR-amplified nodA gene indicated that seven strains representing different 16S and 23S ribosomal DNA genotypes had identical nodA sequences. These data indicate that, whereas microsymbionts of A. sinicus exhibit chromosomal diversity, their nodulation genes are conserved, supporting the hypothesis of horizontal transfer of nod genes among diverse recipient bacteria.

Acyltransferases↗
PubMed2000

In situ estrogen synthesized by aromatase P450 in uterine leiomyoma cells promotes cell growth probably via an autocrine/intracrine mechanism.

In the present study we characterized in detail the expression of aromatase P450 in leiomyomas to determine the role of in situ estrogen in the growth advantage of leiomyomas. The levels of aromatase P450 transcripts were determined by quantitative RT-PCR to be significantly higher in leiomyomas than in corresponding myometrium. The overexpression of aromatase P450 in leiomyomas was also confirmed by Western blot analysis. The estimated size of immunoreactive aromatase was 58 kDa, similar to that in placenta. To identify a cell type that express aromatase P450 in leiomyomas, histological specimens were stained for aromatase P450 using a polyclonal antibody. Strong immunoreactivity was detected in the cytoplasm of leiomyoma cells, whereas surrounding normal myometrium displayed weak or negative staining. Smooth muscle-like cells in culture obtained from leiomyomas, positive for actin D fiber, possessed immunoreactive granules of aromatase in the cytoplasm. Conversion of androgen to estrogen was effectively stimulated by phorbol myristate acetate and dexamethasone plus interleukin-1beta and was completely abolished by selective inhibitors of aromatase P450 (fadrozole and TZA-2209), but not by inhibitors of 5alpha-reductase (finasteride and flutamide). The apparent Km of androstenedione was 3 nM in the presence of dexamethasone and interleukin-1beta, corresponding to the plasma concentration of androstenedione in women of reproductive age. To determine whether endogenous aromatase P450 plays a role in the growth promotion of leiomyoma cells, we evaluated the cell growth of smooth muscle-like cells treated with various concentrations of estrogen and androgen using a WST-1 assay. Treatment with testosterone (10(-8) and 10(-7) M) and androstenedione (10(-8) and 10(-7) M) stimulated the growth of smooth muscle-like cells obtained from leiomyomas to the same extent as estradiol (10(-10)-10(-7) M), whereas dihydrotestosterone (10(-11)-10(-8) M) did not. The stimulatory effect of testosterone on cell growth was again abolished by cotreatment with fadrozole. The level of estradiol in the medium of testosterone (10(-8) M)-treated smooth muscle-like cells was 10(-11) M, which was 1 order lower than the minimum concentration of estradiol necessary to promote cell growth (10(-10) M). This indicates that estradiol synthesized in leiomyomas promotes their growth via an autocrine/intracrine mechanism. We conclude that myometrial cells of leiomyomas overexpress aromatase P450 and are able to synthesize sufficient estrogen to accelerate their own cell growth. Overexpression of aromatase P450 may play a role in the growth advantage of leiomyoma tissue over surrounding myometrium via an autocrine/intracrine mechanism.

Adult↗
PubMed2000

Molecular differentiation of three species of Metagonimus by simple sequence repeat anchored polymerase chain reaction (SSR-PCR) amplification.

Genomic DNAs from 3 species of Metagonimus in the Republic of Korea, M. yokogawai, M. miyatai, and M. takahashii, were amplified by simple sequence repeat anchored polymerase chain reaction. Primers of 3' or 5' termini of the (CA)n repeats were used; 3 kinds of 3' anchored primers (CA)8RG, (CA)4RG, and (CA)8RY, and 2 kinds of 5' anchored primers BDB(CA)7C and DBDA(CA)7. The results showed distinguishable banding patterns among the 3 species of Metagonimus, suggesting that they have different genotypes.

Animals↗
PubMed2000

Persisting antibody reaction in paragonimiasis after praziquantel treatment is elicited mainly by egg antigens.

Antibody responses in serum and cerebrospinal fluid (CSF) samples from patients with active and chronic paragonimiasis and in sera from patients on whom follow-up studies were done after praziquantel treatment were analyzed using antigens of Paragonimus westermani prepared from eggs, metacercariae, juveniles of 4- and 7-week old, adult worms and recombinant protein of 28 kDa cruzipain-like cysteine protease (rPw28CCP). The patient sera/CSFs of active and chronic paragonimiasis revealed strong antibody reactions against the crude extracts of 4- and 7-week old juveniles as well as against those from egg and adult. rPw28CCP also showed specific reaction to the sera with active paragonimiasis. After the treatment, levels of specific antibodies in the sera gradually decreased to negative range in most patients. In some cases with persisting high antibody levels, however, the reactions at 27 kDa egg protein were sustained throughout the observation period of 34 months. The reactions at 35 and 32 kDa in adult extract and rPw28CCP disappeared rapidly after the treatment. Persistent antibody reactions even after successful treatment are provoked by continuous antigenic challenge from eggs which were not resolved by treatment.

Animals↗
PubMed2000

Seroprevalence of toxoplasmosis in the residents of Cheju island, Korea.

This study was performed to evaluate the epidemiological status of toxoplasmosis among the residents of Cheju island. The sera of local students from 18 high schools (boys 2110, girls 2460) and those of adults (474 admitted to Cheju Chungang General Hospital) were collected and checked for the IgG antibody titers against Toxoplasma gondii. Serum samples collected from both the students and adults showed sero-positive rate of 5.5% and 12.9%, respectively. Although the rates were not significantly different between the sexes (5.4% for the boys and 5.5% for the girls attending school), the geographical difference showed a significant difference between the urban (4.6-6.9%) and rural areas (5.6-8.8%) (p < 0.05). Based on the high positive rates, it should be necessary to control toxoplasmosis in Cheju island.

Adolescent↗
PubMed2000

IgG antibody responses in early experimental sparganosis and IgG subclass responses in human sparganosis.

Antigenic components in the crude extracts of Spirometra mansoni plerocercoid were analyzed in early experimental infections and in IgG subclass observed in clinical sparganosis. By IgG immunoblot, sera obtained serially from experimental mice, fed 5 spargana each, were reacted with the crude extracts. Protein bands at 36-26 kDa and 103 kDa showed positive reactions since two weeks after infection. In a differential immunoblot, in which a monospecific antibody against sparganum chymase at 36 kDa was pre-treated, the reactions at 36-26 kDa disappeared, indicating that the sparganum chymase and its degradation products invoked IgG antibody reactions. When 69 patients sera of human sparganosis were examined for their IgG subclass responses, IgG4 levels showed the highest reaction which was followed by IgG1. The IgG4 antibody also reacted mainly with 36-31 kDa protease. These results indicate that 36 kDa chymase of S. mansoni plerocercoid is the main antigenic component inducing IgG antibody response in early stage of experimental sparganosis and for specific IgG subclass reactions in human sparganosis.

Animals↗
PubMed2000

[Construction and application of an Escherichia coli high effective expression vector with an enhancer].

In this study, we constructed a high effective fusion expression-vector in E. coli. This vector, pTO-T7, was characterized as: (1) an enhancer from tobacco mosaic virus (TMV), omega sequence, was ligated in front of a T7 promoter in the regulatory sequence; (2) the multi-cloning sites include eight restriction enzyme sites. It can facilitate fusion or nonfusion expression; (3) the N terminal of a fusion protein starts with the first 12 amino acids of T7 gene 10, and the C terminal is the hexahistidine tag; (4) kanmycin resistance gene was used as a selective marker. EGFP gene was inserted into pTO-T7 vector as a reporter gene. Expression data showed that fused-EGFP accounted to more than 50% of the total E. coli protein, and more than 90% of which was soluble. The fluorescence characters of fused-EGFP were also studied. The expression yield of target gene from plasmid pTO-T7 compared with that from pT-T7 without omega sequence suggested that omega sequence in pTO-T7 can improve the expression of target gene significantly.

Base Sequence↗
PubMed2000

[Relationship between the sensitivity to tetraethylammonium and firing patterns of injured dorsal root ganglion neurons].

In order to study the relationship between the firing patterns of injured dorsal root ganglion (DRG) neurons of rat and their sensitivity to tetraethylammonium (TEA), spontaneous activities from single fibers of chronically compressed DRG neurons were recorded. Two patterns of spontaneous activity were found: periodic pattern and non-periodic pattern. These two types of neurons showed different sensitivity to TEA with 27.3% in periodic and 93.2% in non-periodic firing neurons responding to TEA (2 mmol/L) (P<0.01). The responses to TEA of different concentrations were greater in the non-periodic firing neurons than in the periodic firing ones (P<0.01). The responses to TEA became apparent in 5 neurons after their periodic firing pattern was transformed into non-periodic firing pattern through an increase in Ca(2+). The non-periodic interburst interval of the bursting discharge decreased significantly while the periodic burst interspike interval had no response to TEA. The unstable period orbits were found in bursting discharge, indicating deterministic chaos during bursting discharge. It is concluded that non-periodic firing neurons with chaos are more sensitive to TEA than periodic firing neurons.

Animals↗
PubMed2000

[Determination of alpha-naphthylacetic acid by high performance liquid chromatography].

A high performance liquid chromatographic method for the determination of alpha-naphthylacetic acid has been established on a Hypersil C18 column(4.6 mm i.d. x 250 mm, 5 microns), with the mobile phase of methanol-water-phosphoric acid(60:40:0.35, V/V), and UV detection at 272 nm. The linear correlation was observed within the range of 16 mg/L-1,000 mg/L(r = 0.9997). The RSD was 0.8%(n = 5). The method is simple and accurate.

Chromatography, High Pressure Liquid↗
PubMed1999

Supratentorial primitive neuroectodermal tumor in children: clinical features, treatment outcome and prognostic factors.

To investigate clinical features, treatment outcome and prognostic factors of pediatric supratentorial primitive neuroectodermal tumors(ST-PNETs), 28 ST-PNET cases were retrospectively analyzed. The prognostic importance of age, sex, size of tumor, M stage, extent of surgical resection, histological features, immunohistochemical labelling indices (Ki-67, p53), and apoptotic index were assessed. The mean age at diagnosis was 6.8 years, and the male-to-female ratio was 18:10. The presenting symptoms in 22 cases were increased intracranial pressure and focal neurological deficits. Gross total resection was achieved in 17 cases, near-total (>90%) resection in 3, and subtotal in 7; biopsy was performed in 1 case. The mean duration of follow-up was 37 months. For 25 patients who completed planned adjuvant therapy, the 3-year survival rate was 73%. Univariate analysis showed that the presence of tumor necrosis (P=0.002) and extent of resection (P=0.04) correlated with survival. Patients with a high Ki-67 labelling index (>10%) tended to have shorter survival (P=0.095). In multivariate analysis, tumor necrosis showed statistical significance(P=0.03).

Adolescent↗
PubMed1999

Jugular foramen schwannomas: surgical approaches and outcome of treatment.

Twelve cases of schwannomas of the jugular foramen that involved surgery in our department between 1983 and 1997 are described. Eight were women and 4 were men (mean age, 40 years), and the duration of their symptoms, the most predominant of which were hearing loss and tinnitus, ranged from 1 month to 20 years (median, 8.5 months). Depending on their radiological and surgical features, tumors were classified as type A, a tumor primarily at the cerebellopontine angle with minimal enlargement of the jugular foramen (n = 5); type B, a tumor primarily at the jugular foramen with or without intracranial extension (n = 4); type C, a primarily extracranial tumor with extension into the jugular foramen (n = 0); or type D, a dumbbell tumor with both intracranial and extracranial components (n = 3). A retrosigmoid suboccipital craniectomy (RSSOC) was performed for type A tumors; for types B and D, the RSSOC or staged infratemporal fossa approach (ITFA)/RSSOC was used. Total removal was achieved in 6 cases, near total removal in 3, and subtotal removal in 3. The most common complication was lower cranial nerve dysfunction (n = 5). The follow-up period ranged from 6 to 173 (mean, 48) months, and there was no recurrence. Two patients showed regrowth of the tumor after subtotal resection, however. In 1 of these, the residual tumor had progressed within 12 months of initial surgery, it was again resected and linac radiosurgery was successful. In the other, the residual mass had progressed within 8 months of initial surgery, and the pathological report indicated malignant peripheral nerve sheath tumor. Conclusively, type A tumors could be totally resected with the retrosigmoid approach alone. For type B and D tumors, however, combined ITFA and retrosigmoid approach showed the better results. In spite of our limited data, cases showing adhesion to critical structures can be managed by subtotal or near total resection followed by radiosurgery to reduce postoperative complications.

Journal Article↗
PubMed1999

A point mutation in the albumin gene in a Chinese patient with familial dysalbuminemic hyperthyroxinemia.

Familial dysalbuminemic hyperthyroxinemia (FDH) is an autosomal dominant disorder characterized by euthyroid hyperthyroxinemia. However, FDH has not been reported in Chinese or African patients. Here, we report the first case of FDH in a Chinese patient. A 69-year-old Chinese man was found to have increased serum total T(4) concentrations (198-242nmol/l; normal range 58-148nmol/l) and free T(4) concentrations (>58pmol/l; T(4) analog method, normal range 9-28pmol/l). Serum total T(3) and TSH concentrations were normal. The patient was misdiagnosed as hyperthyroid and was later suspected to have a TSH-producing tumor by the finding of a pituitary microadenoma, which was eventually proven to be a non-functional pituitary 'incidentaloma'. Electrophoretic analysis of the patient's serum proteins demonstrated enhanced albumin binding of [(125)I]T(4). Serum free T(4) concentrations were normal (16-19pmol/l, normal range 9-26pmol/l) when a two-step method was used. Direct sequencing of the albumin gene showed a guanine to adenosine transition in the second nucleotide of codon 218, resulting in a substitution of histidine (CAC) for the normal arginine (CGC) in one of the two alleles in the patient. The point mutation was further confirmed by HphI digestion of exon 7 of the albumin gene. The patient's son was not affected. Our studies demonstrated that the point mutation of the albumin gene in a Chinese patient with FDH was similar to that found in western white families, but differed from that in a Japanese family in whom a guanine to cytosine transition at the same position was found.

Aged↗
PubMed1999

Identification of IgE-reacting Clonorchis sinensis antigens.

Clonorchis sinensis is a liver fluke and it is the most prevalent human parasite in Korea at present. The parasite infection induces immune responses, characteristically an increased production of parasite-specific IgE in the host. Major IgE-reacting C. sinensis antigens in infected humans have been protein bands with MWs of 15, 28, 37, 45, 51, 56, 62, 66, 74, 97 and 160 KD identified by immunoblot analysis. Individual variations of the IgE binding pattern to C. sinensis antigens have also been documented. Using immune BALB/c mouse sera, IgE-reacting protein bands have been visualized with MWs of 28, 74, 86, 160 and several > 200 KD. One of the most strongly reacted C. sinensis antigenic proteins with a molecular weight of 28 KD was purified by gel filtration and preparative electrophoresis. Using a monoclonal antibody produced against the antigenic protein, the protein was localized in the parasite's intestine, and also found to be contained in excretory-secretory antigens.

Animals↗
PubMed1999

Clinical response and patient acceptance of a prefilled, disposable insulin pen injector for insulin-treated diabetes.

BACKGROUND: The aim of this study was to evaluate the clinical response and patient acceptance of a prefilled, disposable insulin pen injector (Novolet, Novo-Nordisk, Bagsvaerd, Denmark) for treating insulin-dependent diabetic patients. METHODS: After a run-in period of six weeks, 19 patients participated in an open, randomized, controlled, crossover study with two 12-week periods using insulin pens or conventional syringes. Clinical responses were assessed every 12 weeks, including glycosylated hemoglobin (HbA1c), seven-point blood glucose profiles and hypoglycemic reactions. At the end of the trial, patients completed questionnaires about their acceptance of the insulin delivery device. RESULTS: Neither of the regimens rendered significant changes in HbA1c, blood glucose profiles or hypoglycemic episodes. Most of the study subjects reported that the prefilled, disposable devices were convenient and easy to use, and many of them wished to continue using the device for insulin delivery. CONCLUSIONS: The clinical response was the same for both treatment regimens, but most subjects preferred the prefilled disposable pen injector for insulin delivery because it was more convenient for daily use.

Adult↗