Biomedical subjects

Y H Yang

Publications and source records attributed to Y H Yang.

At least 37 records · Page 2Linked to original sources

PubMed2001

Evaluation of Binax NOW, an assay for the detection of pneumococcal antigen in urine samples, performed among pediatric patients.

In our evaluation of a new assay for the detection of pneumococcal antigen in urine (Binax NOW; Binax), the test result was no more likely to be positive among 88 children with radiographically confirmed pneumonia than among 198 control subjects; however, it was significantly more likely to be positive among children who were nasopharyngeal carriers of pneumococci. This test is not likely to be useful for distinguishing children with pneumococcal pneumonia from those who are merely colonized.

Antigens, Bacterial↗

PubMed2001

Dependence of interleukin-1-induced arthritis on granulocyte-macrophage colony-stimulating factor.

OBJECTIVE: To determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage CSF (M-CSF or CSF-1) are involved in the methylated bovine serum albumin/interleukin-1 (mBSA/IL-1)-induced arthritis model. METHODS: Following systemic injection, IL-1 has been shown to augment a weak inflammatory response to mBSA in murine joints and to induce an acute erosive arthritis. GM-CSF and M-CSF have been implicated in inflammatory reactions, including those in joints, and have recently been shown to exacerbate murine arthritis. Since in vitro studies have found that IL-1 can enhance GM-CSF and M-CSF production, we reasoned that they might be playing a part in IL-1-mediated arthritis. GM-CSF-deficient (GM-CSF-/-) and M-CSF-deficient (op/op) mice were injected intraarticularly with mBSA and subcutaneously with IL-1. Arthritis was monitored histologically on day 7. Normal mice were also treated intraperitoneally with blocking monoclonal antibodies to GM-CSF and M-CSF, and to the M-CSF receptor. Numbers of macrophages (Mac-2 and F4/80 staining) were monitored, as was the number of cycling (bromodeoxyuridine-positive) cells. RESULTS: GM-CSF-/- mice and normal mice treated with anti-GM-CSF antibody did not show IL-1-induced arthritis progression. There was a dramatic reduction in synovial cellularity, including reduced numbers of macrophages and cycling cells. The op/op mice did not develop mBSA/IL-1-induced disease, but blocking antibody to M-CSF or to the M-CSF receptor failed to diminish disease in normal mice. CONCLUSION: GM-CSF is involved in the IL-1-induced arthritis that follows mBSA injection; M-CSF involvement in the model is also suggested, since op/op mice did not develop arthritis. These studies provide the first in vivo evidence for a role of GM-CSF, and possibly M-CSF, in the proinflammatory actions of IL-1.

Animals↗

PubMed2001

The effect of mechanical forces (vibration or external compression) on the dermal water content of the upper dermis and epidermis, assessed by high frequency ultrasound.

An ultrasound scanner, is used to detect changes in water content of the upper dermis. This has previously been found to vary with age and to show diurnal variation. Furthermore, oedema due to venous disease can be shown, using this technique, to respond to elevation. In this study, the water content of the upper dermis and epidermis of the leg in 16 subjects is increased following vibration for 10 minutes using a passive exercise system. A study of pressure applied to the skin of the heel for 10 minutes in 14 volunteers also showed an increase in water content of epidermis and dermis in young persons, but less so in the elderly. It is postulated that the anatomical structure of the vascular bed of the upper dermis predisposes to transsudation when pressure to the skin is applied, thereby maintaining the resilience of the skin in the young, but less so in the elderly.

Adult↗

PubMed2001

Beta2-agonist exerts differential effects on the development of cord blood T cells but not on peripheral blood T cells.

Asthma is a chronic inflammatory disease characterized by reversible airway obstruction caused by edematous airway lining, thickened mucosal secretions, and smooth muscle constriction. Beta2-adrenoceptor agonists are widely used in the treatment of bronchial asthma because of their ability to induce relaxation of airway smooth muscle. Evidence indicates that desensitization and down-regulation of beta-adrenoceptors occurs in long-term beta2-agonist therapy, and these medications were thought to cause increased severity of, and mortality in, asthma. The purpose of this study was to delineate further the potential adverse effects of beta2-agonists on the development of T lymphocytes. T cells isolated from umbilical cord blood and adult peripheral blood were cultured in the presence of salbutamol. Intracellular staining with fluorescence-labeled antibodies was used to differentiate the frequency of type 1 T-helper (Th1) and type 2 T-helper (Th2) cells. The results showed a statistically significant inverse relationship between the concentration of salbutamol and the ratio of Th1 over Th2 on cord blood T cells. However, this trend was not observed in adult peripheral blood T cells. The data revealed another potential adverse effect in which chronic beta2-agonist exposure predisposed differentiation of T lymphocytes towards Th2 while that of Th1 was relatively suppressed, especially in cord blood T cells. Hence, beta2-agonists, despite their effect in symptomatic rescue in asthma, should not be used indiscriminately as long-term therapeutic agents.

Adrenergic beta-Agonists↗

PubMed2001

Epidemiological survey of oral submucous fibrosis and leukoplakia in aborigines of Taiwan.

A population-based survey was designed to investigate the prevalence of areca/betel quid chewing, oral submucous fibrosis and leukoplakia in a typical aboriginal community of southern Taiwan. Three hundred and twelve people 20 years of age or older were collected in the study. The prevalence of chewing areca/betel quid was 69.5%, with an average of 17.3 portions a day for an average 24.4 years. More women (78.7%) than men (60.6%) chewed areca/betel quid. The prevalences of oral submucous fibrosis and leukoplakia were 17.6% and 24.4%, respectively. It was found that the odds ratio for chewing areca/betel quid and having at least one of the above oral mucosal lesions was 8.21. Any additional smoking or drinking habits were not significant for having oral mucosal lesions. Although the areca/betel quid in Taiwan does not contain any tobacco, a significant association was still identified between areca/betel quid chewing and oral mucosal lesions.

Adult↗

PubMed2001

Nitrogen removal from sewage by continuous flow SBR system with intermittent aeration.

A continuous-flow sequential batch reactor system with intermittent aeration known as the intermittent cycle extended aeration system was used to investigate the efficiencies of nitrogen removal for sewage. In the conventional intermittent cycle extend aeration system with continuous aeration process to treat the synthetic sewage wastewater under 3 cycles per day (cycle time = 8 hours), high COD removal efficiencies were achieved, but high levels of nitrate (22.3-23.6 mg l-1) and decreased pH values were also found in the effluent. In the intermittent aeration, the dissolved oxygen in the reactor was reduced from the range of 3.5-5.0 mg l-1 to 0.5-1.2 mg l-1, the nitrogen in the influent was partially oxidized to nitrite-nitrogen, although nitrate-nitrogen was also present in the effluent. In detailed cyclic study of the reactor with relatively low D.O. (0.3-1.0 mg l-1) and high MLSS (3200 mg l-1 at half full water level), the experimental results of intermittent aeration processes showed higher oxidation rates of ammonia to nitrite (1.44-3.55 mg N g-1 MLSS hr-1) than the conversion rates of nitrite to nitrate (0.00-1.22 mg N g-1 MLSS hr-1). It was thus, concluded that denitrification rates were not affected by the limited supplement of soluble organic carbon in the system. In addition, NOx(-)-N could be removed with a total nitrogen removal rate up to 94.9% when the MLSS was controlled in concentrations of 3200 mg l-1 at half full water level with low D.O. The process of intermittent aeration of ICEAS could provide an economic and effective means for nitrogen removal in treating sewage.

Bioreactors↗

PubMed2001

Analysis of cDNA microarray images.

Microarrays are part of a new class of biotechnologies that allow the monitoring of expression levels for thousands of genes simultaneously. Image analysis is an important aspect of microarray experiments, one that can have a potentially large impact on subsequent analyses, such as clustering or the identification of differentially expressed genes. This paper reviews a number of existing image analysis methods used on cDNA microarray data. In particular, it describes and discusses the different segmentation and background adjustment methods. It was found that in some cases background adjustment can substantially reduce the precision--that is, increase the variability of low-intensity spot values. In contrast, the choice of segmentation procedure seems to have a smaller impact.

Data Interpretation, Statistical↗

PubMed2001

Chronic hepatitis C virus infection associated with primary warm-type autoimmune hemolytic anemia.

Autoimmune hematologic abnormalities are not well recognized in chronic hepatitis C virus infection. We demonstrate an unusual association between primary autoimmune hemolytic anemia and chronic hepatitis C virus infection. A 69-year-old woman who had a history of hepatitis C virus-related liver cirrhosis was found to have deteriorating anemia with reticulocytosis when admitted to the hospital. Laboratory work revealed both positive direct and indirect Coombs' tests, and warm-type immunoglobulin G against surface antigens of red blood cells. After prednisolone therapy, her anemia improved dramatically. To our knowledge, this is the first reported case of chronic hepatitis C virus infection linked with autoimmune hemolytic anemia in its natural course, not related to prior interferon treatment. Our report suggests that isolated autoimmune hemolytic anemia may be one of the unusual hematologic manifestations of chronic hepatitis C virus infection.

Aged↗

PubMed2001

Physician control of pediatric antimicrobial use in Beijing, China, and its rural environs.

BACKGROUND: Antibiotic resistance is recognized as an increasing problem in China. It is widely believed that because antibiotics are available without a prescription, changing physician prescribing behaviors will not decrease inappropriate usage. This study identified the sources of antibiotics and the important influence that physicians have on antibiotic use by children in one region of China. METHODS: Trained medical professionals surveyed parents of children attending several kindergartens in urban Beijing and rural Gu'An, Hebei County. Parents completed a questionnaire concerning the children's recent illnesses, care-seeking patterns and antibiotic use. The team also observed hospital- and non-hospital-based pharmacy purchases of antibiotics for children, assessed the proportion accompanied by a prescription and then interviewed parents about factors influencing those purchases. RESULTS: Of 241 urban and 143 rural kindergarten parents, 76 to 82% usually obtained children's antibiotics from a hospital pharmacy (with a prescription). For 84% the first source of care was usually a physician (primarily western medicine, sometimes traditional Chinese medicine). Only 5% of antibiotics were obtained from independent vendors without prior physician consultation. Among 229 observed antibiotic purchases 72% occurred at hospital-based facilities, even after longer observation times at nonhospital pharmacies. Prescriptions accompanied all hospital-based antibiotic purchases, contrasting with 18% of nonhospital transactions (P < 0.001). Together 86% of parents self-reported that the observed purchase stemmed from a doctor's recommendation. CONCLUSIONS: Doctors directly and indirectly controlled the majority of antibiotic usage for childhood illnesses in Beijing and Gu'An (Hebei County). Physician education and implementation of treatment guidelines might substantially reduce inappropriate antimicrobial usage and help prevent antimicrobial resistance in this region.

Anti-Bacterial Agents↗

PubMed2001

Evaluation of a medium (STGG) for transport and optimal recovery of Streptococcus pneumoniae from nasopharyngeal secretions collected during field studies.

Field studies of Streptococcus pneumoniae (pneumococci) nasopharyngeal (NP) colonization are hampered by the need to directly plate specimens in order to ensure isolate viability. A medium containing skim milk, tryptone, glucose, and glycerin (STGG) has been used to transport and store NP material, but its ability to preserve pneumococci has not been evaluated. Our objective was to qualitatively and semiquantitatively evaluate the ability of STGG to preserve pneumococci in NP secretions. Entwined duplicate calcium alginate NP swab samples were obtained from children. One swab was plated directly onto a gentamicin blood agar plate; the other was placed in STGG. Growth from the directly plated specimen was compared with growth from an STGG aliquot immediately cultured or stored at -70 degrees C for 9 weeks, -20 degrees C for 9 weeks, or 4 degrees C for 5 days. Of 186 specimens, 96 (52%) were positive for pneumococci from the direct plating; 94 (98%) of these were positive from the fresh STGG specimen. Pneumococci were recovered from all 38 positive specimens frozen at -70 degrees C, all 18 positive specimens frozen at -20 degrees C, and 18 of 20 positive specimens stored at 4 degrees C. Recovery of pneumococci after storage of NP material in STGG medium at -70 degrees C is at least as good as that from direct plating. Storage at -20 degrees C is also acceptable. Storage at 4 degrees C for 5 days is not ideal.

Child, Preschool↗

PubMed2001

Triple marker screening for fetal chromosomal abnormalities in Korean women of advanced maternal age.

The purpose of this article is to assess the value of maternal serum triple marker screening of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) for the prenatal diagnosis of fetal chromosomal abnormalities in Korean women of advanced maternal age. Maternal sera were collected from 458 pregnant Korean women aged 35 between 15 and 20 weeks gestation before amniocentesis. A patient- specific second trimester risk for fetal Down's syndrome was calculated using the median values for AFP, hCG, uE3 and maternal age. Twelve fetal chromosomal abnormalities were identified. These included six cases of trisomy 21, one case of 46,XY/47,XY,+21, two cases of trisomy 18, one case of trisomy 13, and two cases of 45, X. A cutoff level of 1:200 detected 85.7% (6/7) of the cases of Down's syndrome and 20% (1/5) of the other aneuploidies, with a 27.3% false positive rate. However, a cutoff level of 1:270 did not result in any gains in detecting Down's syndrome or other aneuploidies at the expense of a false positive rate of 34.3%. Second trimester triple marker testing is an effective screening tool for detecting fetal Down's syndrome in Korean women > or = 35 years old. However, it is not an effective screening tool for non-Down's chromosomal abnormalities.

Adult↗

PubMed2001

A case with balanced chromosome rearrangement involving chromosomes 9, 14, and 13 in a woman with recurrent abortion.

A phenotypically normal couple was referred for cytogenetic evaluation due to three consecutive first-trimester spontaneous abortions. Chromosomal analysis from peripheral blood was performed according to standard cytogenetic methods using G-banding technique. The husband's karyotype was normal. The wife's karyotype showed a balanced complex chromosome rearrangement (CCR) involving chromosomes 9, 14, and 13. There were three breakpoints: 9p21.2, 14q21, and 13q12.2. The karyotype was designated as 46, XX, t (9;14;13)(p21.2;q21;q12.2). Fluorescence in situ hybridization (FISH) analysis with chromosome-specific libraries of chromosomes 9, 14, and 13 was performed to confirm this rare chromosome rearrangement. The result of FISH coincided with that obtained by standard cytogenetic techniques.

Abortion, Habitual↗

PubMed2001

Correlation of cervical vertebra maturation with hand-wrist maturation in children.

The purpose of this study was to evaluate the reliability of cervical vertebra maturation as an indicator of skeletal age during the circumpubertal period. This was determined by correlating cervical vertebra maturation to hand-wrist maturation. The vertebral skeletal age was assessed using lateral cephalometric radiographs according to maturity indicators modified from Lamparski. The hand-wrist skeletal age was evaluated in radiographs with the system developed by Fishman. The sample consisted of 503 subjects (244 boys and 259 girls), aged 8 through 18 years. The Spearman rank correlation coefficients and Wilcoxon sign rank test showed that a statistically significant relationship existed between the two assessments. Both the intra- and inter-judge tests of reliability displayed no significant differences. The results of this study indicate that skeletal age assessment made from the maturational changes of cervical vertebrae were reliable, reproducible and valid.

Adolescent↗

PubMed2001

Acute lupus pneumonitis mimicking pulmonary tuberculosis: a case report.

We report a case of systemic lupus erythematosus in a 15-year-old girl with initial presentation as acute lupus pneumonitis. A fulminant course with pancytopenia and respiratory distress were developed 3 weeks after symptom onset. Chest radiographs revealed an interstitial pattern with miliary nodules over bilateral lower lung fields that mimics miliary tuberculosis. The patient was treated with intravenous immunoglobulin and antituberculosis drugs because the infection-associated hemophagocytic syndrome and pulmonary tuberculosis could not be excluded from the clinical course. The response to antituberculosis treatment, however, was poor and her respiratory condition deteriorated rapidly to impending respiratory failure 1 week after admission. Systemic lupus erythematosus with acute lupus pneumonitis was then diagnosed based on the fulminant clinical course and accordant laboratory results. Corticosteroid (methylprednisolone) and cytotoxic agent (cyclophosphamide) pulse therapies were applied twice and once, respectively. She recovered gradually after receiving the immunotherapy.

Acute Disease↗

PubMed2001

The effects of arecoline on the release of cytokines using cultured peripheral blood mononuclear cells from patients with oral mucous diseases.

In Taiwan there is a significant correlation between oral precancer diseases and oral cancer associated with the betel quid chewing habit. The carcinogenic components of betel quid are arecoline, arecaidine and safrole. However, it is unknown whether these substances influence the immune functions. This study investigated the effects of betel quid on the immune system using cultured peripheral blood mononuclear cells from patients with oral mucous diseases. In our experiment, mononuclear cells from 10 normal persons, 12 patients with precancer lesions, and 16 patients with squamous cell carcinoma were separated from blood samples and cultured. After stimulation by arecoline, the amounts of IL-2, TNF-alpha, TGF-beta and IFN-gamma secreted by mononuclear cells were measured using the ELISA method. The results showed that IL-2, TNF-alpha, and TGF-beta were significantly lower in mononuclear cells of normal persons as stimulated by arecoline. The TGF-beta amount in cells from oral submucous fibrosis patients with betel quid chewing habit (OSF-B) was lower than normal persons or patients who had long term betel quid chewing habit but were without oral mucosal diseases (N-B), and was also lower than the squamous cell carcinoma with betel quid chewing group (SCC-B). TNF-alpha was significantly lower in the squamous cell carcinoma with long term betel quid chewing group (SCC-B) than in normal persons. TNF-alpha was significantly higher in the squamous cell carcinoma without betel quid chewing group (SCC-N) than in normal persons and SCC-B groups. In addition, IFN-gamma was significantly lower in patients who had long term betel quid chewing but were without oral mucous lesions than the normal person and the OSF group. The results proved that betel quid influences cytokines production by mononuclear cells.

Arecoline↗

PubMed2001

[The expression characteristics and their biological significance of epidermal growth factor and basic fibroblast growth factor in rat skins at different development stages].

OBJECTIVE: To explore the localization and expression characteristics of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) in rat skins at different development stages (embryonic, newborn, adult). METHODS: Skins from embryonic, newborn and adult rats were taken, and detected by immunohistochemical technique. RESULTS: Positive immunohistochemical signal of EGF could be found in skins from embryonic, newborn and adult rats, mainly in the cytoplasm of the epidermal cells, fibroblasts, hair follicle epithelial cells, and endothelial cells. With the increase in age, the expression amount of EGF was increased. The positive signal of bFGF could be found in skins of newborn and adult rats, while the signal of bFGF in skin of embryonic rats was negative. CONCLUSION: The results indicate that endogenous EGF plays important role in epidermal development in embryonic stage and wound healing in adult after injury. The negative expression of bFGF in skin of embryonic rat indicate that the absence of bFGF may be one of the reasons for the non-scar healing in embryonic stage.

Animals↗

PubMed2001

Risk factors of wheeze and allergy after lower respiratory tract infections during early childhood.

Lower respiratory tract infections (LRIs) during early childhood can lead to bronchial hyperreactivity or recurrent obstructive bronchitis. The role of LRIs in the pathogenesis of allergic diseases such as allergic rhinoconjunctivitis, atopic eczema, and bronchial asthma is less clear. The aim of this retrospective study was to determine the incidence of subsequent wheezing and atopy, and the known risk factors for allergic sensitization in 74 children hospitalized for acute LRIs of various etiologies from January 1994 through December 1994. Results showed that there are no differences in outcomes between patients with respiratory syncytial virus LRI, Chlamydia pneumoniae LRI, and LRIs caused by other agents. Although lower respiratory tract illnesses, especially those caused by respiratory syncytial virus during infancy, were associated with an increased risk of subsequent wheezing during early childhood, wheezing tended to disappear with increasing age in many children. This study also found recurrent episodes of wheezing during the first 5 years of life, and symptoms suggestive of allergic rhinoconjunctivitis were the only factors predictive of subsequent diagnosis of asthma for children who had LRIs during early childhood. In conclusion, this study suggests that prevention of recurrent wheezing LRIs and good control of allergic rhinoconjunctivitis is critical for preventing subsequent development of bronchial asthma.

Asthma↗

PubMed2001

Clinical characteristics of neonatal lupus erythematosus.

Neonatal lupus erythematosus is a rare disorder caused by transplacental autoantibodies from the mother to the fetus. This syndrome is characterized by congenital heart block and/or cutaneous lesion. A total of 10 cases of neonatal lupus erythematosus were diagnosed at the National Taiwan University Hospital from 1988 through 1998. The incidence of cardiac anomaly and other clinical features in patients with neonatal lupus erythemayosus in this study was compared with those in previous studies. Results showed that 50% of patients had congenital heart block and/or cutaneous lesion, which is compatible to previous statistics. However, the findings showed that 80% of the patients were female and 90% of the mothers had acquired an autoimmune disorder, which were much higher compared with that of other studies. To date, no definite treatment is suggested prenatally to prevent the occurrence of congenital heart block, but careful maternal screening and serial fetal echocardiogram are warranted.

Antibodies, Antinuclear↗