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Biomedical subjects

C H Chen

Publications and source records attributed to C H Chen.

At least 163 records · Page 9Linked to original sources
PubMed2000

Oxidized low-density lipoproteins inhibit endothelial cell proliferation by suppressing basic fibroblast growth factor expression.

BACKGROUND: Hyperlipidemia inhibits proliferation of endothelial cells (ECs) in culture and angiogenesis in vivo and in arterial explants. Elucidation of the mechanisms may suggest novel therapies against atherosclerosis. METHODS AND RESULTS: Basic fibroblast growth factor (bFGF) expression and mitogenic effects were assessed in bovine aortic ECs incubated with oxidized LDL (ox-LDL). Compared with native LDL and lipoprotein-free controls, ox-LDL reduced bFGF mRNA levels in a time- and concentration-dependent manner, 100 microg/mL producing a maximum reduction of 40% to 50% within 24 to 48 hours. There were commensurate reductions in intracellular and extracellular bFGF concentrations, DNA and total RNA syntheses, and cell replication. FGF receptor 1 and beta-actin mRNA levels were unchanged. Ox-LDL accelerated bFGF mRNA degradation in actinomycin D-treated cells. However, inhibition of bFGF expression by ox-LDL was attenuated by cyclohexamide, indicating a requirement for continuous new protein synthesis for posttranscriptional destabilization. Reduced syntheses of DNA and total RNA were completely restored by bFGF but not by vascular endothelial growth factor. Inhibition of total RNA synthesis achieved by exposing cells to a bFGF-neutralizing antibody was similar in magnitude to that induced by ox-LDL. CONCLUSIONS: Cytotoxic effects of ox-LDL on ECs are attributable in part to suppression of bFGF expression.

Animals↗
PubMed2000

Effect of increasing dose of interferon on the evolution of hepatitis C virus 1b quasispecies.

The effects of interferon therapy on hepatitis C virus (HCV) genome are still controversial in terms of biological and clinical significance. Changes in the quasispecies of the hypervariable (HVR) and non-structural 5A (NS5A) regions of HCV 1b were evaluated in nine patients treated with increasing doses of interferon and five untreated controls. HCV quasispecies were analyzed in HVR and NS5A by single-strand conformation polymorphism assay. The HVR quasispecies varied over time both in treated and untreated patients. However, at least one persistent strain was present in all patients. With low doses of interferon, variations in HVR complexity were found in seven of nine patients and in four patients new variants became detectable. A reduction in the heterogeneity of the HVR quasispecies was observed after increase of the interferon dose. In contrast, NS5A profiles remained unmodified in all but three cases in which direct sequencing showed no changes in amino acid sequences of the predominant strain. The results suggest that interferon sensitivity of some HCV strains may be dose dependent. The homogeneity of NS5A pattern populations during treatment suggests that interferon exerts much less pressure on this region.

5' Untranslated Regions↗
PubMed2000

The effects of weight reduction on the rehabilitation of patients with knee osteoarthritis and obesity.

OBJECTIVE: To evaluate the effect of weight reduction on the rehabilitation of patients with knee osteoarthritis and obesity. METHODS: A total of 126 patients with bilateral knee osteoarthritis and obesity were classified into 3 groups by their stages of osteoarthritis. Each group was divided into subgroups a, b, and c. The subjects in subgroup a received weight reduction treatment, those in subgroup b received weight reduction and electrotherapy modalities, and those in subgroup c received electrotherapy modalities to relieve pain. RESULTS: Pain reduction, weight reduction, ambulation speed, and changes of Lequesne's index were greater in patients in subgroups a and b than in subgroup c after treatment. Although the last pain scores in subgroup b were less than those in subgroup a, as measured by a visual analog scale (VAS), there was no significant difference between their functional status. Significant pain relief (VAS < 2) and an acceptable functional status (Lequesne's index < 7) were indicated when weight reduction was more than 15% and 12%, respectively, of the initial body weight of the individual. CONCLUSION: Weight reduction was found to be a practical adjuvant treatment in the rehabilitation of patients with knee osteoarthritis.

Acupuncture Therapy↗
PubMed2000

Increased arterial wave reflection may predispose syncopal attacks.

BACKGROUND: The incidence of syncope increases with age, while aging is also associated with increased arterial wave reflection. HYPOTHESIS: The study was undertaken to determine whether increased arterial wave reflection is a predisposing factor of syncope. METHODS: We recruited 38 patients (28 men and 10 women, mean age 57.2 +/- 20.3 years, range 17-87 years) with a history of syncope within 6 months of entry. The etiology of syncope was documented for each patient by a complete assessment of vasomotor function and cerebral flow. All patients received a comprehensive echocardiographic evaluation of cardiac structure and function. Carotid augmentation index (AI) was estimated noninvasively with the tonometry technique. The results were compared with those from 54 age- and gender-matched controls. RESULTS: The most frequent diagnoses of syncope were postural hypotension (13 patients) and cerebrovascular dysautoregulation (10 patients), and the cause could not be determined in 9 patients. Compared with the control group, the syncope group had a greater AI (20 +/- 21 vs. 10 +/- 15%, p = 0.013). Subgroup analysis of 20 patients aged > 50 years and with the aforementioned diagnoses showed even more striking results: AI, 29 +/- 10 vs. 11 +/- 15%, p < 0.001. The enhanced augmentation in the patients remained when age, systolic blood pressure, height, and heart rate were accounted for. Analysis of the carotid pulse wave suggested that both the timing and intensity of wave reflection were enhanced in patients with a history of syncope compared with controls. CONCLUSIONS: Our results support the hypothesis that enhanced arterial wave reflection is associated with the occurrence of syncope, especially in the elderly.

Adolescent↗
PubMed2000

Basement membrane macromolecules: insights from atomic force microscopy.

The major macromolecules of basement membranes-collagen IV, laminin-1, and heparan sulfate proteoglycan (HSPG)-have been analyzed by atomic force microscopy (AFM), both individually and in combination with each other. The positions of laminin binding to collagen IV were mapped and compared with the positions of imperfections in the amino acid sequence of collagen IV; the apparent molecular volumes of the HSPG proteoglycans were measured and used to estimate the corresponding molecular weights. Even the thin, thread-like strands of the polyanion heparan sulfate can be visualized with AFM without staining, coating, or fixation. These strands are single polysaccharide chains and are thus thinner than single-stranded DNA. The heparan sulfate strands in HSPG are necessary for protein filtration in kidney basement membranes. We propose that these thin strands filter proteins by functioning as an entropic brush-i.e., that they filter proteins by their constant thermally driven motion in the basement membrane. These AFM analyses in air are a step toward AFM analyses under fluid of basement membrane macromolecules interacting with each other.

Animals↗
PubMed2000

The prevalence of heavy proteinuria and progression risk factors in children undergoing urinary screening.

To evaluate the prevalence and incidence density of heavy proteinuria and chronic renal insufficiency (CRI) and the factors related to disease progression, 10,288,620 urinary screenings of elementary and junior high-school students from 1992 to 1996 were studied retrospectively. Urinary screening included pH, protein, occult blood, and glucose measurements. Blood sample analysis included total protein, albumin, A/G ratio, blood urea nitrogen, creatinine (Cr), antistreptolysin O titer, C3, cholesterol, hepatitis B virus surface antigen, IgA, and fasting blood sugar. The results showed that the 4-year prevalence of proteinuria was higher in girls than in boys (6.87x10(-4) vs. 4.83x10(-4) respectively). There were 189 cases with disease progression into CRI among the 10,288,620 students screened and followed continuously, with the prevalence of disease progression into CRI higher in boys than in girls (2.24x10(-5) vs. 1.41x10(-5) respectively). Of the 119 cases (63%) presenting with CRI since the first urine screening and blood sampling, only 14 had serum Cr levels higher than 6.0 mg/dl. There were 1,289 patients (10.5%) with proteinuria in 1992 and 705 patients (7.1%) in 1996. The absolute number of patients with heavy proteinuria decreased. The percentage of underlying glomerulonephritis in children on dialysis also decreased from 63.2% in 1992 to 47.0% in 1996. Logistic regression analysis showed that a persistent serum cholesterol level higher than 220 mg/dl, an albumin level lower than 3.5 g/dl, total protein less than 6 g/dl, and diastolic pressure higher than 90 mmHg were the significant risk factors for disease progression to CRI. We conclude that early detection of students with heavy proteinuria by mass urinary screening, early appropriate treatment, and monitoring of significant risk factors may help to decrease or delay the progression of renal disease, delay the introduction of dialysis in these predialysis CRI patients and maintain their growth and development.

Adolescent↗
PubMed2000

Self-organizing arterial pressure pulse classification using neural networks: theoretical considerations and clinical applicability.

A self-organizing classification system for the arterial pressure pulse based on the ART2 (adaptive resonance theory) network was developed. The system consists of a preprocessor and an ART2 recognition network. The preprocessor removes the arterial pressure pulse servo component signals from Finapres, detects the systolic pressure points and divides the acquired signals into minimal cardiac cycles. The ART2 network input is the minimal cardiac cycle detected by the preprocessor. The classification results can be used to assist physicians in evaluating the signs of abnormal and normal autonomic control and has shown its clinical applicability for the examination of the autonomic nervous system.

Artifacts↗
PubMed2000

Ipsilateral fractures of the femoral neck and shaft.

Ipsilateral femoral shaft and neck fractures are difficult to treat. From 1989 to 1998, we treated 18 patients with these complex fractures. There were 14 male and 4 female with an average age of 40 years. Most resulted from high-energy trauma. The average follow-up period is 41 months. All but one of the fractures united well. The mean time to union is 5.2+/-2.3 months in the diaphysis and 4.16+/-2 months in the neck. No cases of the femoral neck fracture or osteonecrosis of the femoral head were observed during the follow-up period. Fourteen cases were treated with a standard protocol of plates for diaphyseal fractures and lag screws or dynamic hip screws (DHS) fixations for the femoral neck fractures. There were 13 good and 1 fair functional results. Two neglected neck fractures were treated with interlocking nailing for diaphyseal fracture with fair results. We conclude that a plate on the shaft and sliding hip screws or separate screws in the hip is a reliable method for ipsilateral femoral neck and shaft fractures.

Activities of Daily Living↗
PubMed2000

A 10-year follow-up study of contraceptive Norplant implants.

OBJECTIVES: To evaluate the long-term efficacy and health problems associated with Norplant implants and re-implants after 5 full years of first implants. METHOD: From 1984 to 1988, 1657 women accepted first implants of Type I and Type II of Norplant, and 394 first acceptors had a re-implant, at a clinic for study. The clinical records and annual follow-up data of acceptors were analyzed. The life-table technique was the main method used. RESULTS: The continuation rates were very high. The cumulative pregnancy rates at 1, 3 and 5 full years of use were 0.0%, 0.1% and 0.7%, respectively. Users with heavier body weight had higher pregnancy rates. The rate of menstrual disturbances peaked at 73% after 3 months and consistently decreased to 20% at 5 years of use. Rates of menstrual disturbances associated with re-implants were much lower. CONCLUSION: Norplant is extremely effective and safe for long-term use.

Adult↗
PubMed2000

Effects of support group intervention in postnatally distressed women. A controlled study in Taiwan.

OBJECTIVE: The symptoms of depression experienced by women during the postnatal period may have profound effects on the lifelong health of both the mother and the child. In this randomized controlled study, we systematically evaluated the effects of weekly supportive group meetings for women with postnatal distress. METHODS: Sixty postnatally distressed women were randomly assigned to support (n=30) and control (n=30) groups. Women assigned to the support group participated in four supportive group sessions that comprised discussions concerning transition to motherhood, postnatal stress management, communication skills, and life planning. RESULTS: Subjects who attended the support sessions had significantly decreased scores on the Beck Depression Inventory (BDI) and the Perceived Stress Scale (PSS), and significantly increased scores on the Interpersonal Support Evaluation List (ISEL) as evaluated at the end of the fourth weekly session. In contrast, no significant changes were observed in the control group during this period. CONCLUSION: This is the first controlled study to provide evidence that participation in support groups for postnatally distressed women provides quantifiable psychosocial benefits.

Adult↗
PubMed2000

Antigen-specific immunotherapy for human papillomavirus 16 E7-expressing tumors grown in the liver.

BACKGROUND/AIMS: We have previously reported a recombinant vaccinia-based vaccine (vac-Sig/E7/LAMP-1) that demonstrated a significant anti-tumor effect in a subcutaneous tumor challenge model. Since the liver is one of the most common sites for tumor metastasis and organ microenvironments may modulate tumor cell responses to therapies, the aim of the present study was to evaluate the potency of vac-Sig/E7/LAMP-1 in treating E7-expressing tumors grown in the liver. METHODS: For in vivo tumor prevention experiments, mice were vaccinated intraperitoneally with vac-Sig/E7/LAMP-1 followed by intrahepatic tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with vac-Sig/E7/LAMP-1 intraperitoneally. In addition, enzyme-linked immunospot assays were used to determine the frequency of E7-specific T cell precursors. RESULTS: For in vivo tumor protection experiments, tumor growth was observed in all of the mice vaccinated with wild-type vaccinia and 60% of the mice vaccinated with wild-type E7 vaccinia. All of the mice vaccinated with vac-Sig/E7/LAMP-1 remained tumor-free 30 days after tumor challenge. For the tumor regression assays, all of the mice vaccinated with vac-Sig/E7/LAMP-1 remained tumor-free 30 days after vaccination. In contrast, all of those mice receiving culture medium, wild-type vaccinia, or wild-type E7 vaccinia developed tumors in the liver. In addition, mice vaccinated with vac-Sig/E7/LAMP-1 had the highest E7-specific CD8+ T cell precursors. CONCLUSIONS: Our data suggest that vac-Sig/E7/LAMP-1 is an effective vaccine for controlling E7-expressing tumors grown in the liver and our model suggests that antigen-specific immunotherapy may represent a powerful tool for treating liver tumors with characterized tumor-specific antigens. In addition, our data indicate that the number of E7-specific CD8+ T cell precursors directly correlated with the anti-tumor effect generated by Sig/E7/LAMP-1 vaccinia.

Animals↗
PubMed2000

Prevalence of subclinical cryoglobulinemia in maintenance hemodialysis patients and kidney transplant recipients.

We studied the prevalence and the clinical spectrum of cryoglobulinemia (Cryo) among 101 maintenance hemodialysis (HD) patients and 148 kidney transplant (KT) recipients, with or without chronic hepatitis C virus (HCV) infection. Cryo was present in 32% (16 of 50) of the HCV-positive HD patients, 5.9% (3 of 51) of the HCV-negative HD patients, 37.8% (28 of 74) of the HCV-positive KT recipients, and 27% (20 of 74) of the HCV-negative KT recipients. Cryoprecipitate in 56.3% (9 of 16) of the HCV-positive Cryo HD patients and 53.8% (14 of 26) of the HCV-positive Cryo KT recipients contained HCV-RNA. Interestingly, the cryocrit values among HD and KT patients were much lower than these in other reports on nonrenal failure cases. Also, the cryoglobulinemic syndrome (with purpura, arthralgia, etc.) in HD and KT patients with Cryo were not common (Tables 1 and 2). There was not correlation between Cryo and age,sex, and liver function. Only longer duration of end-stage renal disease was noted in these patients. In addition, we suggested that KT patients are more susceptible to having Cryo. Further studies are necessary to better define whether any other subclinical viral or nonviral chronic infection may induce Cryo in HCV-negative KT recipients.

Adult↗
PubMed2000

Community-based epidemiological study of glucose tolerance in Kin-Chen, Kinmen: support for a new intermediate classification.

In this population-based survey, we investigated the prevalence of varying degrees of glucose tolerance among residents of Kin-Chen, Kinmen, as well as the association of glucose tolerance status with potential risk factors for type 2 diabetes and cardiovascular disease (CVD). We focused particularly on subjects with normal 2-h postload glucose level (<7.8 mmol/l) but persistent fasting hyperglycemia (PFH) (5.6-7.8 mmol/l), to examine whether PFH represents an intermediate state between normal glucose tolerance (NGT) and impaired glucose tolerance (IGT). The target population comprised 6346 residents aged 30 years and older. A total of 4354 subjects could be classified into categories of NGT, PFH, IGT, new diabetes, and known diabetes according to medical history, fasting plasma glucose levels, and the results of a 75-g oral glucose tolerance test (OGTT). The potential cardiovascular risk factors assessed included age, obesity (general and central), systolic blood pressure, and fasting levels of insulin, C-peptide, triglyceride, cholesterol, and high-density lipoprotein cholesterol (HDL-C). The age-standardized prevalences of PFH, IGT, new diabetes, and known diabetes were 2.9%, 3.5%, 4.0%, and 3.0%, respectively. Among nondiabetic subjects, the cardiovascular risk factor profiles worsened with decreasing glucose tolerance, with most values differing significantly among the NGT, PFH, and IGT groups. Subjects with PFH, who would be classified as having NGT according to conventional WHO criteria, had physical and biochemical features between those of the NGT and IGT groups. These findings support our previous observation that PFH may be a transition state between NGT and IGT in the progression toward type 2 diabetes.

Adult↗
PubMed2000

Different association of hypertension and insulin-related metabolic syndrome between men and women in 8437 nondiabetic Chinese.

Insulin resistance may cause a metabolic syndrome but whether insulin resistance causes hypertension is very controversial. Furthermore, it remains unclear whether the link between the insulin-resistance-related metabolic syndrome and hypertension is different between men and women. We examined fasting insulin, glucose, triglyceride and high-density lipoprotein (HDL)-cholesterol levels, systolic blood pressure, body mass index, and waist-to-hip ratio in a dataset from 8437 nondiabetic residents (age range, 30 to 89 years) in Kinmen. Factor analysis, a multivariate correlation statistical technique, was used to investigate the clustering and interdependence of these risk variables. Factor analysis identified two factors for men (n = 3659) and three factors for women (n = 4778, respectively. In men, a cluster of insulin, triglyceride, HDL-cholesterol, body mass index, and waist-to-hip ratio (metabolic syndrome) accounted for 29.7%, and a cluster of systolic blood pressure and glucose (hyperglycemia plus hypertension) accounted for 18.1% of the total variance in all variables considered. In women, a cluster of insulin, triglyceride, body mass index, waist-to-hip ratio, and systolic blood pressure (metabolic syndrome plus hypertension) accounted for 29.4%, a cluster of systolic blood pressure, glucose, and triglyceride (hyperglycemia plus hypertension plus dyslipidemia) accounted for 14.0%, and a cluster of triglyceride and HDL-cholesterol (dyslipidemia) accounted for 16.2% of the total variance. In conclusion, a distinct insulin-resistance-related metabolic syndrome characterized by hyperinsulinemia, dyslipidemia, and obesity was observed for both men and women in this Chinese population. However, hypertension was linked to the metabolic syndrome in women only.

Adult↗