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Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 343 records · Page 19Linked to original sources
PubMed1996

Distribution of 7-alkyl-2'-deoxyguanosine adduct levels in human lung.

Human lung tissue is frequently studied as a target organ for DNA damage from carcinogen-DNA adducts. In order to assess the distribution of carcinogen-DNA adducts in human lung, we measured 7-methyl-2'-deoxyguanosine-3'-monophosphate (7-methyl-dGp), 7-ethyl-2'-deoxyguanosine-3'-monophosphate (7-ethyl-dGp) and 4-hydroxy-(3-pyridyl)-1-butanone (HPB)-releasing DNA adducts in different lobes. The first two result from exposure to N-nitrosamines, including tobacco-specific nitrosamines, and the latter only from tobacco-specific nitrosamines. Using a chemically-specific 32P-postlabeling assay for 7-alkyl-2'-deoxyguanosines, adducts were measured in eight separate lung segments of ten autopsy donors. 7-Methyl-dGp levels were detected in all eighty samples (range from 0.3 to 11.5 adducts/10(7) dGp; mean 2.5 +/- 2.3 adducts/10(7) dGp). 7-Ethyl-dGp were detected in all but five of the samples (range from <0.1 to 7.1 adducts/10(7) dGp; mean 1.6 +/- 1.7 adducts/10(7) dGp). 7-Methyl-dGp levels were approximately 1.5-fold higher than 7-ethyl-dGp levels, and they were positively correlated with each other in most individuals. There was no consistent pattern of adduct distribution in the different lobar segments. Most individuals, especially those with the lowest levels, had similar levels among the lobes, while those with the highest levels had a widely variable pattern ranging as much as ten-fold. Moreover 7-methyl-dGp and 7-ethyl-dGp levels in all people showed a highly significant inter-individual variation (P = 0.0001). The levels of 7-alkyl-2'-deoxyguanosine among individuals could not be explained by differences in tobacco exposure (measured by serum cotinine), onset of death, gender, age, race, blood ethanol, or ventilation and perfusion variability. In an effort to corroborate 7-alkyl-2'-deoxyguanosine adducts variability among lobes or individuals, we sought to determine a correlation with HPB-releasing DNA adducts as an independent marker of tobacco exposure. However, this tobacco- specific carcinogen-DNA adduct could not be detected in four individuals tested (detection limit: 0.3 adducts per 10(7) dGp). Based upon the lack of 7-alkyl-2'-deoxyguanosine discernible adduct patterns, no conclusions could be drawn regarding a potential relationship to lobar cancer incidence. The results indicate that in studies of carcinogen-DNA adducts, such as 7-alkyl-dGp in human lungs, for most individuals a random lung sample would be representative of other parts of the lungs. Some individuals however might be misclassified due to highly variable 7-alkyl-dGp levels.

Adult↗
PubMed1996

A population-based study of the incidence of malignant small bowel tumours: SEER, 1973-1990.

BACKGROUND: Little is known about the incidence of cancers of the small bowel. METHODS: Data from cancer registries participating in the Surveillance, Epidemiology, and End-Results (SEER) Program from 1973 to 1990 were analysed to determine the incidence of the four major histological types of cancer occurring in the small intestine: adenocarcinomas, malignant carcinoid tumours, lymphomas and sarcomas. In addition, the incidence rate of lymphomas arising from the small intestine and stomach and adenocarcinomas from the small intestine, stomach and colon were compared over time. RESULTS: Small bowel tumours occurred rarely, with an average annual incidence rate of 9.9 per million people. Carcinoid tumours and adenocarcinomas were the most common histological subtypes, with average annual incidence rates of 3.8 and 3.7 per million people respectively, followed by lymphomas (1.1 per million people) and sarcomas (1.3 per million people). For all histological subtypes, men had higher rates than women. Most tumours occurred in older adults; over 90% of cases occurred in people over the age of 40. During the 18-year study period, the incidence of small bowel tumours has risen slowly. In white men, black men and black women, rises in the incidence of adenocarcinomas, malignant carcinoids and lymphomas contributed to this trend. In white women, the incidence of adenocarcinomas, was stable while malignant carcinoids and lymphomas rose. The incidence of sarcomas was steady for all groups except black women, for which it fell. The histological types were distributed by anatomical subsite: adenocarcinomas were distributed more proximally on average whereas lymphomas were more common distally. In addition, there was an association between the incidence trends of adenocarcinomas occurring in the duodenum and colon suggesting similar risk factors for cancers in these regions. There was no similar correlation for tumours in the jejunum and ileum. The incidence of lymphomas over time rose in all areas of the small intestine, paralleling a similar rise in lymphomas of the stomach. CONCLUSIONS: Cancers of the small bowel are rare despite a slow increase over the past two decades, especially among lymphomas. Higher rates in males and whites deserve further investigation.

Adenocarcinoma↗
PubMed1996

Molecular cloning of inhibin/activin beta A-subunit complementary deoxyribonucleic acid and expression of inhibin/activin alpha- and beta A-subunits in the domestic hen.

A chicken inhibin/activin beta A-subunit cDNA clone has been isolated and used to detect the beta A-subunit mRNA in the hen. A cDNA library of the hen granulosa layer was screened with a rat inhibin beta A-subunit cDNA probe, and a cDNA of 1540 bp was cloned and sequenced. The clone contains the entire open reading frame of 1272 nucleotides encoding 424 amino acids. It shows 78% nucleotide identity (85% in deduced amino acids) in the full-length coding region and 85% nucleotide identity (98% in deduced amino acids) in the 116-amino acid C-terminal mature region to the rat beta A-subunit cDNA clone. The predicted positions of one N-linked glycosylation site and all cysteine residues are fully conserved as well. Northern blot analysis showed that the major 8.4-kb inhibin/activin beta A-mRNA band was primarily expressed in the granulosa layer of the preovulatory follicles. It was also detected in much less abundance in the theca layer, thyroid gland, heart, muscle, intestine, adrenal gland, liver, lung, spinal cord, and spleen. When a chicken inhibin alpha-subunit cDNA probe was used, the 1.7-kb major band of the inhibin alpha-subunit mRNA was detected most strongly in the granulosa layer and less abundantly in the postovulatory follicle, theca layer, testis, heart, and adrenal gland. Moreover, a distinct 1.3-kb alpha-mRNA was detected in the muscle and lung. The present cloning study extends our understanding of the inhibin/activin beta A-subunit cDNA from studied species to the chicken and shows that the beta A-subunit is highly conserved during evolution. Our data indicate that the mRNAs for inhibin/activin alpha- and beta A-subunits are widely present in a variety of chicken tissues but that the granulosa layer of large preovulatory follicles is the primary site of expression. The present study also suggests that both inhibin and activin may serve as local factors to regulate cell function in chicken tissues.

Activins↗
PubMed1996

Expression of inhibin alpha and inhibin/activin beta A subunits in the granulosa layer of the large preovulatory follicles of the hen.

The expression of the mRNA for the inhibin/activin subunits (alpha and beta A) in the granulosa layer of the five largest preovulatory follicles of the hen was investigated. Total RNA from the granulosa layer of the F5 (the fifth largest) to F1 (the largest) follicles was extracted and analyzed by Northern blot analysis using homologous chicken inhibin alpha and beta A subunit cDNA probes. RNA loading was quantified by a cDNA probe of bovine 18S rRNA. Results showed that for the chicken inhibin alpha subunit mRNA signals (n = 3), the mean relative intensity for the F1, F2, F3, and F4 follicles was 0.50 +/- 0.10 ( +/- SEM,), 0.52 +/- 0.08, 0.59 +/- 0.06, and 0.81 +/- 0.04, respectively, compared to a mean relative intensity of 1.00 (p < 0.05) for the F5 follicle. For the beta A subunit mRNA signals (n = 3), the mean relative intensity for the F5, F4, F3, and F2 follicles was 0.25 +/- 0.06, 0.28 +/- 0.15, 0.40 +/- 0.17, and 0.48 +/- 0.10 (p < 0.05) for the F1 follicle. The inhibin alpha subunit was also estimated to be more abundantly expressed among follicles in the granulosa layer than was the beta A subunit. Our data indicate that the expression of inhibin alpha and beta A subunits is differentially regulated in the hen granulosa layer during follicular development. Expression of the alpha subunit is reduced with follicular development whereas inhibin beta A subunit expression is dramatically enhanced. In addition, the granulosa layer of the large preovulatory follicles may produce more inhibin alpha subunit than beta A subunit, and the F1 follicle may be the primary source of the beta A subunit for dimeric inhibin and/or activin in the hen.

Activins↗
PubMed1996

Tumor necrosis factor-alpha, platelet-activating factor, and hydrogen peroxide activate protein kinase C subtypes alpha and epsilon in human saphenous vein endothelial cells.

Protein kinase C (PKC), the major receptor for tumor-promoting phorbol esters, consists of a family of at least 12 distinct lipid-regulated enzymes. We examined the expression and regulation of PKC isoforms in human saphenous vein endothelial cells (HSVEC). Western blot analysis with PKC isoform-specific antibodies indicated that PKC alpha, PKC epsilon and PKC zeta were expressed in these cells. Translocation and down-regulation of PKC alpha and epsilon but not zeta were detected by short-term and long-term treatment with TPA (12-O-tetradecanoylphorbol 13-acetate), respectively. Tumor necrosis factor-alpha (TNF-alpha 1,600 U/ml) and platelet activating factor (PAF 50 nM) increased the membrane content of PKC alpha and epsilon but not zeta. H2O2 (10 mM) induced the translocation of PKC alpha from the cytosol to the membrane and increased PKC epsilon content in both cytosol and membrane. However, 12-(S)-HETE (12-hydroxyeicosatetraenoic acid) (100 nM), a lipoxygenase metabolite of arachidonic acid, did not affect the two isoforms. These results suggest that the molecular action of TNF-alpha, PAF, and H2O2 in HSVEC might occur through PKC alpha and epsilon activation.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1996

Metabolic bone disease of liver cirrhosis: is it parallel to the clinical severity of cirrhosis?

Metabolic bone disease has long been recognized in chronic liver disease, especially cholestatic or alcoholic liver diseases. The aim of the present study was to investigate the prevalence and severity of osteodystrophy in cirrhotic men and the correlation of its incidence with the clinical severity of cirrhosis in an endemic area of post-necrotic hepatitis. We measured serum levels of osteocalcin, 25-hydroxyvitamin D, parathyroid hormone mid-molecule, calcium and testosterone in 74 cirrhotic men (Child-Pugh's classification grade A n = 30, B n = 21 and C n = 23) and 16 healthy controls. Standard X-rays and bone mineral densities of lumbar spine were performed in 30 patients with post-necrotic cirrhosis and 10 healthy controls. Serum levels of osteocalcin, parathyroid hormone and testosterone were significantly lower in patients with cirrhosis than in controls. Changes paralleling an increased severity of cirrhosis were found in serum levels of 25-hydroxyvitamin D and testosterone, but not in the serum levels of osteocalcin and parathyroid hormone. The lumbar bone mineral density was significantly lower in patients with post-necrotic cirrhosis than in controls (0.97 +/- 0.13) vs 1.07 +/- 0.12 g/cm2, P < 0.05) and was correlated with serum 25-hydroxyvitamin D levels (r = 0.467; P < 0.005). There was no correlation between the bone mineral density and serum osteocalcin or the clinical severity of cirrhosis. The prevalence of spinal osteoporosis, as defined by a lumbar bone mineral density greater than two standard deviations below the mean value of the controls, was 20% in cirrhotic patients compared with 10% in controls. Two (6.7%) patients (both grade C) had spinal compression fractures compared with none in the control group. In conclusion, serum osteocalcin and lumbar bone mineral density were significantly lower in cirrhotic men than in controls. However, they were not correlated with each other or the clinical severity of cirrhosis.

Aged↗
PubMed1996

Serum procarboxypeptidase B, amylase and lipase in chronic renal failure.

Procarboxypeptidase B (human pancreas-specific protein) has been reported to be a good serum marker for the diagnosis of acute pancreatitis. The current study was conducted in order to evaluate the frequency and degree of elevated serum levels of procarboxypeptidase B in chronic renal failure and their correlations with serum levels of amylase, lipase and renal function tests. Blood samples were taken from 84 asymptomatic patients with chronic renal failure, including 34 patients with periodical haemodialysis and 50 patients without haemodialysis. Serum levels of procarboxypeptidase B, amylase, lipase, creatinine and blood urea nitrogen were measured. Serum levels of procarboxypeptidase B in 84 patients were 63.4 +/- 5.5 micrograms/L significantly greater than the figure of 29.6 +/- 1.6 micrograms/L in healthy adults in our previous report (P < 0.0001). There was a significant difference in serum levels of PCPB between patients with and without haemodialysis (78.0 +/- 9.4 vs 53.6 +/- 6.3 micrograms/L; P < 0.01). The frequencies of elevated serum levels of procarboxypeptidase B, amylase and lipase greater than upper normal limits were 27.4, 35.7 and 26.2%, respectively. The frequencies of elevated PCPB in patients with and without haemodialysis were 38.2 and 20%, respectively. Only one patient had a serum procarboxypeptidase B level greater than three-fold the upper normal limit. A significant correlation was found between procarboxypeptidase B and lipase (r = 0.785; P < 0.0001). No significant correlation was noted between procarboxypeptidase B vs amylase or renal function tests. In conclusion, in patients with chronic renal failure, the elevation of serum procarboxypeptidase B is as common as the elevations of other pancreatic enzymes.

Aged↗
PubMed1996

Parathyroid adenomas in the aortopulmonary window.

PURPOSE: To describe localization studies in nine patients with ectopic parathyroid adenomas in the aortopulmonary window. MATERIALS AND METHODS: Nine patients with ectopic parathyroid tissue (eight adenomas, one hyperplastic gland) in the aortopulmonary window were examined with ultrasound (US), computed tomography (CT), magnetic resonance (MR) imaging, and scintigraphy. Diagnostic arteriography (n = 4) and venous sampling (n = 3) were performed in the first four patients; arteriography for the purpose of staining was attempted in the last five patients. RESULTS: The results of CT and MR imaging studies were positive in eight of nine patients (89%) and five of eight patients (63%), respectively. The results of thallium/technetium scintigraphy were negative in three patients scanned (0%), but the results of a repeat study in one patient were positive (33%). Sestamibi scans were positive in six of six patients (100%). Single photon emission CT was performed in all six patients and enabled distinction between adenomas in the aortopulmonary window and those in the thymus. CONCLUSION: Ectopic parathyroid glands in the aortopulmonary window are usually detected at sestamibi scintigraphy, and SPECT is helpful in distinguishing these adenomas from more common adenomas in the anterior mediastinum. CT and MR imaging studies can also enable this distinction, but imaging must extend below the aortic arch.

Adenoma↗
PubMed1996

Association of monoamine oxidase A alleles with alcoholism among male Chinese in Taiwan.

OBJECTIVE: The role of monoamine oxidase (MAO) in alcoholism was assessed by genetic association studies separately in five ethnic groups in Taiwan. METHOD: Restriction fragment length polymorphisms (RFLP) and dinucleotide repeat polymorphisms (DNRP) were used to determine MAOA and MAOB alleles in male alcoholic patients and nonalcoholic comparison subjects among Han Chinese and four aboriginal groups. RESULTS: Significant associations of alcohol dependence with MAOA alleles (RFLP and DNRP) were found among the Han Chinese, but not among the aboriginal groups. No significant association with MAOB DNRP alleles was found in any group. CONCLUSIONS: Genetic heterogeneity may underlie alcoholism among different ethnic groups in Taiwan, and MAOA mutations may play a role in susceptibility to alcoholism among Han Chinese.

Alcoholism↗
PubMed1996

Alcohol-metabolising genes and alcoholism among Taiwanese Han men: independent effect of ADH2, ADH3 and ALDH2.

BACKGROUND: Previous population association studies have indicated that certain alleles of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) may reduce the risk of alcoholism in Asian populations. The association of ALDH2 and ADH2 with the development of alcoholism was found to be independent of each other and has been replicated in different Asian populations, while the effect of ADH3 is less studied. METHOD: We genotyped the alcohol metabolism genes among Han men with alcohol dependence (n = 46) and their ethnically matched normal controls (n = 63) in Taiwan. Multiple logistic regression was then applied to assess the contribution of ADH3 to alcoholism by controlling the effect of ALDH2 and ADH2. RESULTS: The results of multivariate analyses demonstrated that the odds ratios for an increment of one allele of ADH2*1, ADH3*2 and ALDH2*1 in the development of alcoholism were 4.18, 3.82, and 6.89, respectively. CONCLUSIONS: These findings clearly indicate that all three alcohol-metabolising genes contribute to susceptibility to alcoholism.

Adult↗
PubMed1996

Randomized trial of the cardioprotective agent ICRF-187 in pediatric sarcoma patients treated with doxorubicin.

PURPOSE: We conducted an open-label, randomized trial to determine whether ICRF-187 would reduce doxorubicin-induced cardiotoxicity in pediatric sarcoma patients. METHODS: Thirty-eight patients were randomized to receive doxorubicin-containing chemotherapy (given as an intravenous bolus) with or without ICRF-187. Resting left ventricular ejection fraction (LVEF) was monitored serially with multigated radionuclide angiography (MUGA) scan. The two groups were compared for incidence and degree of cardiotoxicity, response rates to four cycles of chemotherapy, event-free and overall survival, and incidence and severity of noncardiac toxicities. RESULTS: Eighteen ICRF-187-treated and 15 control patients were assessable for cardiac toxicity. ICRF-187-treated patients were less likely to develop subclinical cardiotoxicity (22% v 67%, P < .01), had a smaller decline in LVEF per 100 mg/m2 of doxorubicin (1.0 v 2.7 percentage points, P = .02), and received a higher median cumulative dose of doxorubicin (410 v 310 mg/m2, P < .05) than did control patients. Objective response rates were identical in the two groups, with no significant differences seen in event-free or overall survival. ICRF-187-treated patients had a significantly higher incidence of transient grade 1 serum transaminase elevations and a trend toward increased hematologic toxicity. CONCLUSION: ICRF-187 reduces the risk of developing short-term subclinical cardiotoxicity in pediatric sarcoma patients who receive up to 410 mg/m2 of doxorubicin. Response rates to chemotherapy, event-free and overall survival, and noncardiac toxicities appear to be unaffected by the use of ICRF-187. Additional clinical trials with larger numbers of patients are needed to determine if the short-term cardioprotection afforded by ICRF-187 will reduce the incidence of late cardiac complications in long-term survivors of childhood cancer.

Adolescent↗
PubMed1996

Silent transmission of the dengue virus in southern Taiwan.

Immunoglobulin M (IgM) antibody to dengue virus was examined from a total of 3,099 serum samples collected in southern Taiwan. Of 1,232 sera collected from a junior high school and four elementary schools in Liu-Chiu, 35 were IgM-positive, demonstrating that the dengue virus has been circulating on the island, despite the fact that no epidemic has been reported in the past 10 years. Sixteen of 925 sera collected from three elementary schools in Tung-Kang in 1991 were found to be IgM-positive and two of 192 sera from adults in the local community were positive. The IgM-positive subjects tended to be aggregated around a port. Fishing boats that had stopped in neighboring endemic countries were presumed to have introduced the virus periodically, causing a low level of inapparent infections. In the Kaohsiung area, two of 108 suspected clinical cases and four of 642 community-based sera were IgM-positive. Rapid urbanization has provided appropriate circumstances for vector breeding in this area and the high population density has also increased contact frequency between humans and mosquito vectors. This has, in turn, increased the possibility of silent transmission of the dengue virus via either intermittent reintroduction of the virus or continuation of inapparent infections or both. Establishment of a early warning system using the IgM antibody capture-enzyme-linked immunosorbent assay is suggested for effective monitoring of the disease.

Adolescent↗
PubMed1996

Ultrasound-guided fine needle aspiration biopsy of small pulmonary nodules abutting to the chest wall.

BACKGROUND: Ultrasound (US)-guided needle biopsies in peripheral pulmonary lesions are widely applied. Most pulmonary lesions had a large size. We report our results in evaluating the availability of US-guided fine needle aspiration biopsy (US-guided FNAB) in diagnosing small pulmonary nodules abutting to the chest wall. METHODS: Forty patients, whose chest radiographs showed peripheral pulmonary nodules of diameter smaller than 3.0cm, received chest sonographic examination and US-guided FNAB. Of those, six patients had no definite diagnoses; the remaining 34 patients with pulmonary nodules, we divided into three groups. There were four tiny nodules of diameters smaller than 1.0cm, 11 nodules between 1.1 and 2.0cm, and 19 nodules between 2.1 and 3.0cm. We evaluated the diagnostic yields and rates of complication in relation to the size or nature of the nodule. RESULTS: In the enrolled 40 patients, six were lost to surveillance and had indeterminate diagnoses. Of the remaining 34 patients with proven pathological diagnoses and compatible clinical conditions, the diagnostic yields of US-guided FNAB achieved 88% (30/34) which include 96% (26/27) in malignancies and 57% (4/7) in benign nodules. According to the nodular size, the diagnostic rate achieved 100% (4/4) in tiny nodules, 91% (10/11) in nodules between 1.1 and 2.0cm, and 84% (16/19) in nodules between 2.1 and 3.0cm. Only one patient with a 2.5-cm nodule developed pneumothorax after the US-guided FNAB procedure. CONCLUSIONS: US-guided FNAB is a useful and safe diagnostic tool for small pulmonary nodules abutting to the chest wall. The nodular nature, but not size, affects the diagnostic yields and rates of complication.

Adult↗
PubMed1996

Home parenteral nutrition in children.

From 1985 to 1994, home parenteral nutrition (HPN) was used as the method of feeding nine pediatric patients. Indications for HPN included congenital or acquired short bowel syndrome. Crohn's disease, chronic intractable diarrhea, chronic idiopathic intestinal pseudo-obstruction and Hirschsprung's disease. During the period, two patients died; one of sepsis and the other from hepatic failure. Three of the remaining patients have since moved on to oral feeding, but four patients continued on HPN. The majority of these patients have attained a normal weight and height for age while receiving HPN. All patients were fed via an implanted silicone catheter. Catheters were removed and replaced due to complications including nine episodes of infection, four episodes of occlusion, three episodes of breakage and two episodes of dislodgement. Catheter-related sepsis was the most common cause of morbidity and hospital readmission in patients receiving HPN, but was acceptably rare. Staphylococcus aureus was the most frequently cultured organism from either the catheter tip or the blood. HPN is a relatively safe feeding method for patients who would otherwise remain hospitalized for prolonged periods on parenteral nutrition for permanent or prolonged intestinal failure.

Adolescent↗
PubMed1996

Epidermolysis bullosa letalis with pyloric atresia in an infant.

Epidermolysis bullosa (EB) is a group of inherited diseases, that are characterized by vesiculobullous lesions that arise in response to minimal trauma or friction. The three major groups of EB differ according to the ultrastructural level of cleavage namely: simplex (epidermolytic), junctional and dystrophic (dermolytic). The combination of EB and pyloric atresia in rare and there is a definite association between them. We report a baby boy who died epidermolysis bullosa complications despite successful surgical correction of this pyloric atresia.

Epidermolysis Bullosa, Junctional↗