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Biomedical subjects

C Y Yang

Publications and source records attributed to C Y Yang.

At least 73 records · Page 4Linked to original sources
PubMed1999

Rectal cancer mortality and total hardness levels in Taiwan's drinking water.

The possible association between the risk of rectal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible rectal cancer deaths (986 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (986 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and rectal cancer mortality. Odds ratio and 95% confidence intervals were 1.24 (1.01-1. 55) and 1.38 (1.10-1.73), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for rectal cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.

Age Factors↗
PubMed1999

Esophageal cancer mortality and total hardness levels in Taiwan's drinking water.

The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible esophageal cancer deaths (2084 cases) of Taiwan residents from 1987 through 1996 were compared with deaths from other causes (2084 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year of birth, and year of death. The results show that there is a 42% excess risk of mortality from esophageal cancer in relation to the use of soft water (adjusted odds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an important finding for the Taiwan water industry and human health.

Aged↗
PubMed1999

Distribution of double-negative (CD4- CD8-, DN) T subsets in blood and synovial fluid from patients with rheumatoid arthritis.

Double-negative (CD4- CD8-) T (DNT) cells have been postulated to be potentially autoreactive. However, the role of DNT cells in rheumatoid arthritis (RA) has received limited attention. We investigated the distribution of DNT subsets in peripheral blood (PB) and synovial fluid (SF) from patients with active RA to determine whether these cells have relevance to RA. Two-colour flow cytometric analysis was performed to detect DNT cells in PB from 35 RA patients, 26 healthy controls and in SF aspirated from 19 inflamed rheumatoid joints. The subsets of DNT cells, i.e those expressing T cell receptor alphabeta (alphabeta DNT) or gammadelta (gammadelta DNT) were simultaneously examined. Our results showed that DNT cells constituted a very minor subset of PB lymphocytes. When expressed as a percentage of total lymphocytes, alphabeta DNT levels in normal individuals ranged from 0.27 to 2.08% (average 0.76%), while those of gammadelta DNT ranged from 1.02 to 11.42% (average 3.23%). Compared with normal individuals, RA patients had a similar distribution of alphabeta DNT cells in both PB and SF. However, RA patients had significantly lower levels of gammadelta DNT cells in PB than control subjects (1.38 +/- 1.08% vs 3.23 +/- 2.12%, p<0.05), while the levels of gammadelta DNT cells in SF of RA patients were higher than those in PB from RA patients and normal controls. The difference between PB and SF in RA was statistically significant (3.90 +/- 1.88% vs 1.38 +/- 1.08%, p<0.05). A higher level of gammadelta DNT in SF than their paired PB was consistently noted from nine available paired samples. Our findings suggest that gammadelta NT cells, but not alphabeta DNT cells, are probably relevant to RA. The lower percentage of circulating gammadelta DNT cells might have resulted from migration from the circulation into the synovium, suggesting a role for gammadelta DNT cells in the pathogenesis of rheumatoid synovitis.

Adult↗
PubMed1999

Anatomical and electrophysiological evidence for GABAergic bipolar cells in tiger salamander retina.

Our previous work showed that about 12% of bipolar cells in salamander retina synthesize and take up gamma-aminobutyric acid (GABA), are GABA transporter (GAT)-immunoreactive, and respond with a GAT current to extracellularly applied GABA, suggesting that these bipolar cells use GABA, in addition to glutamate, as a neurotransmitter. Further support for this idea was obtained in this study by use of immunogold electron microscopy and whole-cell patch clamp electrophysiology. Ultrastructural analysis showed that amacrine cell and ganglion cell processes were postsynaptic to GABA-immunoreactive synapses made by bipolar cell axon terminals. Whole-cell recordings were obtained from amacrine and ganglion cells in response to activation of bipolar cells by puffing KCl at their dendrites in the outer plexiform layer. Inhibitory postsynaptic currents were observed in several third order neurons, even after blocking the excitatory postsynaptic responses, generated in the inner plexiform layer, with a combined application of NMDA and non-NMDA receptor antagonists, AP-5 and CNQX. These ultrastructural and electrophysiological data support our previous neurochemical results, and suggest that the retinal through-information pathway in salamander includes both inhibitory GABAergic as well as excitatory glutamatergic synaptic mechanisms.

Action Potentials↗
PubMed1999

Synaptic architecture of glomeruli in lamina II of the chicken spinal cord, as revealed using ultrathin section and freeze fracture techniques.

Synaptic glomeruli in lamina II of the chicken dorsal horn were studied using the freeze fracture technique, and the results were compared with those obtained using the ultrathin section technique. Our findings using the freeze fracture technique were as follows. (1) On the presynaptic P-face of the central terminal, intramembrane particles (IMPs) were arranged circularly around a small dimple which was reported to be a synaptic vesicle attachment site. A distinct area with aggregated large IMPs was found on the postsynaptic E-face of some peripheral neuronal elements. (2) The area with small IMPs intermingled with several dimples and the area with aggregated large IMPs were present juxtaposed on the same central terminal P-face. The area with aggregated large IMPs indicates that the central terminal functions as a postsynaptic element; accordingly, the two areas represent a reciprocal synapse. (3) Distinct IMP aggregates were observed on the P-face of vesicle-containing dendrites which did not face the central terminal. (4) A fractured septate junction was revealed as numerous parallel-lined furrows on the E-face of the central terminal. The distribution of IMPs in the synaptic glomerulus supports the hypothesis that the synaptic glomerulus is the site of the local inhibitory feedback circuit for pain transmission.

Animals↗
PubMed1999

Fracture of the femoral component associated with polyethylene wear and osteolysis after total knee arthroplasty.

Fracture of the femoral component associated with polyethylene wear and osteolysis after total knee arthroplasty (TKA) has not been well reported before. A 63-year-old man with osteoarthritis of the right knee underwent TKA with a New Jersey LCS Knee, with cementing on the tibia and patella but not on the femoral component. After 42 months, in addition to wearing of polyethylene of the tibia and patella, severe osteonecrosis of the medial femoral condyle was noted. Osteonecrosis caused loss of osseous support of the medial flange of the femoral component, and the bone ingrowth of the central and lateral flange to the distal femur was so good that it overcame the yield stress of the metal of the femoral component and caused fracture of the femoral component. The osteolytic area was filled with autogenous iliac bone, and a new femoral component was inserted and cemented. The patient's condition became satisfactory with relief of pain. Although uncommon, fracture of the femoral component does occur associated with polyethylene wear and osteolysis.

Arthroplasty, Replacement, Knee↗
PubMed1999

Calcium and magnesium in drinking water and the risk of death from hypertension.

Many studies have demonstrated a negative association between blood pressure and calcium and magnesium levels. This report examines whether calcium and magnesium in drinking water are protective against hypertension. All eligible hypertension deaths (2336 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (2336 controls), and the levels of calcium and magnesium in the drinking water of these residents were determined. Data on calcium and magnesium levels in drinking water throughout Taiwan have been obtained from the Taiwan Water Supply Corporation. The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. Magnesium levels in drinking water were inversely related to the risk of death from hypertension. The adjusted odds ratios (95% confidence interval) for the highest versus lowest quintiles of exposure was 0.63 (0.47 to 0.84). After adjustment for magnesium levels in drinking water, there was no difference between the groups with different levels of calcium. The results of the present study show that there is a significant protective effect of magnesium intake from drinking water on the risk of hypertension. This is an important finding for the Taiwan water industry and human health.

Aged↗
PubMed1999

Effect of passivation on the dissolution behavior of Ti6A14V and vacuum-brazed Ti6A14V in Hank's ethylene diamine tetra-acetic acid solution Part I Ion release.

This work aims to investigate the effects of three factors, namely: (1) two differently prepared materials (as-polished Ti6A14V and 2 h brazed Ti6A14V); (2) three different surface passivation treatments (34% nitric acid passivation, 400 degrees C heated in air, and aged in 100 degrees C de-ionized water); and (3) periods of immersion time (up to 32 days), on trace element release in Hank's ethylene diamine tetra-acetic acid (EDTA) solution. After passivation and autoclaving treatment, the specimens were immersed in 8.0 mM EDTA in Hank's solution and maintained at 37 degrees C for periods of time up to 32 days. The 400 degrees C -treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the higher thickness and rutile structure of the surface oxides. For acid-passivated and water-aged treatments, a highly significant decrease in the trace levels of Ti, A1, and V is detected from the brazed Ti6A14V compared to those obtained from the Ti6A14V specimens. It is hypothesized that an anatase-rutile transformation of surface TiO_2 is likely to occur, accelerated by the elements of copper and nickel in the brazed specimens. In addition, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-8 day experimental period. The implication of the results is discussed.

Journal Article↗
PubMed1999

Intestinal peptide transport systems and oral drug availability.

The intestinal peptide transport system has broad substrate specificities. In addition to its physiological function of absorbing di- and tripeptides resulting from the digestion of dietary proteins, this transport system also absorbs some orally administered peptidomimetic drugs, including beta-lactam antibiotics, angiotensin converting enzyme inhibitors, renin inhibitors, bestatin, thrombin inhibitors, and thyrotropin-releasing hormone and its analogues. There have been several studies on the mechanism and substrate structure-affinity relationship for this transport system. Rapid progress has been made recently in studies on the molecular basis of the intestinal peptide transport system. A protein apparently involved in peptide transport has been isolated from rabbit small intestines, and genes for human intestinal peptide transporters have been cloned, sequenced and functionally expressed. This review summarizes these studies and addresses the pharmaceutical potential of the intestinal peptide transport system.

Administration, Oral↗
PubMed1999

Increased expression of down-regulatory CTLA-4 molecule on T lymphocytes from rheumatoid synovial compartment.

Since the CTLA-4 molecule expressed on activated T lymphocytes has recently been suggested to be an important negative regulator in autoimmune diseases, this study was undertaken to investigate the expression and function of CTLA-4 on synovial T cells from patients with rheumatoid arthritis. CTLA-4-expressing T cells were detected using a dual fluorescence flow cytometric method. Only a small percentage of peripheral blood T cells from patients with rheumatoid arthritis had detectable surface CTLA-4 expression (mean +/- SD, 1. 89 +/- 1.92%). However, the levels of CTLA-4-positive T cells was increased significantly in rheumatoid synovial fluids (5.44 +/- 4. 96%) and synovial membranes (28.76 +/- 14.30%). To explore the role of CTLA-4 molecule in the inflammation of rheumatoid joints, CTLA-4 was blocked with anti-CTLA-4 antibody to assess its effects on the production of tumour necrosis factor alpha and interleukin 1beta in synovial fluid mononuclear cell culture. The addition of anti-CTLA-4 antibody enhanced the production of tumour necrosis factor alpha and interleukin 1beta in a dose-dependent manner. The data suggest that the expression of CTLA-4 plays a down-regulatory role in rheumatoid articular inflammation. We thus concluded that CTLA-4 was up-regulated on synovial T cells from patients with RA, and the increased CTLA-4 expression might exert a down-regulation effect on tumour necrosis factor alpha and interleukin 1beta production.

Abatacept↗
PubMed1999

In vitro elution of antibiotic from antibiotic-impregnated biodegradable calcium alginate wound dressing.

OBJECTIVE: The authors investigated the calcium alginate dressing as a drug-delivery system for the treatment of various surgical infections. METHODS: Cytotoxicity of the calcium alginate dressing to fibroblasts and HeLa cells was evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MITT) colorimetric assay. The calcium alginate dressing was mixed with vancomycin, and lyophilized or not lyophilized to form two types of antibiotic dressings. The antibiotic dressings were placed in 2 mL of phosphate buffered saline (PBS) or in PBS containing 0.01% calcium ions, and incubated at 37 degrees C. The PBS was changed daily, and the removed solutions were stored at -70 degrees C until the antibiotic concentration in each sample was determined by high performance liquid chromatography assay. RESULTS: The results suggested that the antibiotic dressings present no obvious toxic risk to their use as a drug-delivery system. The concentration of vancomycin in each sample was well above the breakpoint sensitivity concentration (the antibiotic concentration at the transition point between bacterial kill. ing and resistance to the antibiotic) for more than 14 days. The release was most marked during the first 48 hours. The concentration of calcium ions in PBS and the lyophilization of the manufacture process of antibiotic dressings prolonged the antibiotic diffusion duration. The diameter of the sample inhibition zone ranged from 10 to 11 mm, and the relative activity of vancomycin ranged from 62.88% to 92.18%. CONCLUSION: All antibiotic dressings released bactericidal concentrations of the antibiotics in vitro for the period of time needed to treat surgical infections. This study offers a convenient method to meet the specific antibiotic requirement for different patients.

Alginates↗
PubMed1999

Real-time equalization of region-of-interest fluoroscopic images using binary masks.

In region-of-interest (ROI) radiologic imaging, the x-ray beam is attenuated peripherally to the region of interest to reduce patient exposure. This attenuation reduces the peripheral image brightness which may cause contrast in the periphery to also be reduced due to video chain nonlinearity. For optimal viewing, it is necessary that the image brightness and contrast in the periphery be brought back to the levels in the ROI. Previously, digital subtraction angiography roadmapping equipment has been used for this equalization; however, the procedure is not independent of patient and gantry motion. A new motion independent method to achieve this equalization involves dividing the real-time video signal into two digital streams one of which is brightness and contrast enhanced. A pre-acquired binary mask image is created by thresholding the image of a uniform object obtained with the ROI filter in place. This binary mask is used to control the recombination of the two image streams in a digital pipeline processor in order to select the ROI from the unprocessed stream and the periphery from the enhanced stream. This system provides image equalization at 30 frame/s for real-time ROI imaging display. Images from this method demonstrate excellent image quality even for peripheral exposure reduction factors exceeding 10.

Equipment Design↗
PubMed1999

Short-term effect of ozone on the pulmonary function of children in primary school.

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter < or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations < 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.

Adolescent↗
PubMed1999

Grandparents in the United States and the Republic of China: a comparison of generations and cultures.

Grandparent behaviors in the United States and the Republic of China are examined to identify curriculum themes for helping them adjust to their changing role. The 3,286 non-consanguineous subjects included Chinese (n = 751), African Americans (n = 777), Caucasian Americans (n = 1,086), and Mexican Americans (n = 672). Analyses were performed using 1) Generation with three levels (grandparent, parent, and grandchild) and 2) Culture with four levels (Chinese, African American, Caucasian American, and Mexican American). The results revealed significant differences in perceptions about grandparents across cultures as well as between generations within cultures. All three generations reported grandparent strengths and needs. Specific guidelines and curriculum topics are recommended for education to support grandparent development.

Aged↗
PubMed1999

Selective modification of apoB-100 in the oxidation of low density lipoproteins by myeloperoxidase in vitro.

Oxidative modification of LDL may be important in the initiation and/or progression of atherosclerosis, but the precise mechanisms through which low density lipoprotein (LDL) is oxidized are unknown. Recently, evidence for the existence of HOCl-oxidized LDL in human atherosclerotic lesions has been reported, and myeloperoxidase (MPO), which is thought to act through production of HOCl, has been identified in human atherosclerotic lesions. In the present report we describe the formation of 2,4-dinitrophenylhydrazine (DNPH)-reactive modifications in the apolipoprotein (apo) by exposure of LDL to myeloperoxidase in vitro. In contrast with the complex mixture of peptides from oxidation of LDL with reagent HOCl, oxidation with MPO in vitro produced a major tryptic peptide showing absorbance at 365 nm. This peptide was isolated and characterized as VELEVPQL(*C)SFILK..., corresponding to amino acid residues 53-66...on apoB-100. Mass spectrometric analyses of two tryptic peptides from oxidation of LDL by HOCl indicated formation of the corresponding methionine sulfoxide (M=O), cysteinyl azo (*C), RS -N= N-DNP, derivatives of EEL(*C)T(M=O)FIR and LNDLNS VLV(M=O)PTFHVPFTDLQVPS(*C)K, which suggest oxidation to the corresponding sulfinic acids (RSO2H) by HOCl. The present results demonstrate that DNPH-reactive modifications other than aldehydes and ketones can be formed in the oxidation of proteins and illustrate how characterization of specific products of protein oxidation can be useful in assessing the relative contributions of different and unexpected mechanisms to the oxidation of LDL and other target substrates. The data also suggest a direct interaction of the LDL particle with the active site on myeloperoxidase and indicate that effects of the protein microenvironment can greatly influence product formation and stability.

Amino Acid Sequence↗
PubMed1999

Non-insulin-dependent diabetes mellitus with type I multiple symmetrical lipomatosis: a case report.

Type I multiple symmetrical lipomatosis (MSL; Madelung's disease) is characterized by lipomas in the nape of the neck and the supraclavicular and deltoid regions, resulting in a bull-necked appearance (Madelung's collar). It is most common in alcoholic men between 35 and 50 years of age. Type I MSL has been reportedly associated with hyperinsulinemia, but its association with diabetes mellitus is rarely discussed. We describe a case of non-insulin-dependent diabetes mellitus (NIDDM) associated with type I MSL. A 47-year-old alcoholic man presented with a seven-year history of hyperglycemia and progressive neck swelling with dysphagia for one year. Physical examination showed diffuse and symmetrical swelling of the bilateral posterior aspects of the neck. Biochemistry profiles revealed elevated concentrations of fasting serum glucose (276 +/- 16 mg/dl), triglycerides (358 +/- 79 mg/dl) and total cholesterol (323 +/- 28 mg/dl). Endocrinologic studies showed normal thyroid function. Neck sonography revealed diffuse thickening and swelling of the fatty structures of both sides of the neck. Normal sonography showed no fatty deposition in the liver. Maxillary and neck computerized tomography revealed diffuse fat accumulation in the submental and posterior neck regions, with no extension to the superior mediastinum. Fine needle aspiration cytology of the neck masses showed only fat cells. The patient received an oral hypoglycemic agent (glibenclamide 5 mg bid) for blood glucose control and lovastatin (20 mg before bed-time) for hyperlipidemia, and ceased drinking alcohol. The neck swelling resolved markedly after 15 months of medical treatment. This suggests that, in addition to the cessation of alcohol consumption, the reduction of blood glucose and lipid concentrations by medication may also assist in resolving the accumulated fat of type I MSL in patients with NIDDM.

Diabetes Mellitus, Type 2↗
PubMed1999

Kimura's disease of bilateral upper eyelids: a case report.

We present a rare case of Kimura's disease of bilateral upper eyelids. A 41-year-old Chinese male had multiple masses over retroauricular, submandibular regions and bilateral upper eyelids since 13 years previously. Tumor recurred after each surgical excision, chemotherapy and Co 60 radiotherapy. Eosinophilia and elevation of blood immunoglobulin E (IgE) were noted in this admission. We operated on left upper eyelid to relieve the blocking of vision. A diffuse infiltration with numerous fibrotic bands was noted. Histological section showed a lymphoid hyperplasia, remarkable infiltration of eosinophils and proliferation of capillaries. Oral prednisolone 60 mg was given postoperatively. The patient had a satisfactory appearance and a relief of visual block.

Adult↗