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Biomedical subjects

C J Chang

Publications and source records attributed to C J Chang.

At least 181 records · Page 10Linked to original sources

Detection of keratinocyte growth factor (KGF) transcripts from normal human and archival canine benign prostatic hyperplastic tissues.

This study examined the expression of keratinocyte growth factor (KGF) gene in human and canine prostatic tissues. KGF transcript was detected in normal human prostatic tissues by reverse transcription and polymerase chain reactions (RT-PCR). PCR-generated human KGF complementary DNA (cDNA) clone was confirmed by restriction enzyme digestion analysis and partial DNA sequencing. Expression of KGF in archival canine benign prostatic hyperplastic tissues was also examined. In a pilot experiment, RNAs isolated from formalin-fixed (FF) and formalin-fixed and paraffin-embedded (FFPE) canine prostatic tissues were shown to be of sufficient quality to permit amplification of KGF mRNA by RT-PCR. The transcript of a housekeeping gene, glucose-6-phosphate dehydrogenase (G6PD), was detected by RT-PCR indicating the quality of RNAs to be more than adequate for RNA expression analysis. Later, total RNA from two archival canine FF prostate tissue types, benign prostatic hyperplasis and mild glandular hyperplasia, were used to amplify canine KGF transcripts. Southern hybridization analysis using rat and human KGF cDNAs as probes confirmed the fidelity of the amplified PCR product and it was indeed canine KGF.

Animals↗

Frozen preservation of human amnion and its use as a burn wound dressing.

A method of freezing and sterilizing the human amnion enabled it to be stored at -60 degrees C for more than six months. The membranes were obtained from twenty-four cesarean section mothers without a history of endometritis, premature rupture of their membranes or a positive serology. The elongation and break strength of the membranes were evaluated before and after storage. The membranes as prepared have been utilized on twenty-two wounds of ten burn patients. The results indicate that amnion is quite safe and effective as a biological dressing using this preservation method.

Adult↗

[Epidemiological study of anemia in the elderly aged over 65 years in Taiwan].

We investigated the prevalence rate of anemia in a study of the health of the elderly population in four Taiwan urban communities. A total of 2,518 noninstitutionalized persons aged 65-93 were evaluated in 1989-1991. The age-adjusted prevalence rates of anemia (hemoglobin < 12.5 g/dl in men and < 11.5 g/dl in women) were 6.5% in men and 8.3% in women. Prevalence rates increased significantly with age in women, while they were not so prominent in men. The men with anemia had higher creatinine and thyroid stimulating hormone levels, but had lower bilirubin and albumin level than men without anemia. Compared with the non-anemic female group, the anemic women had higher creatinine and lower bilirubin and albumin levels. Regardless of sex, anemic elderly had significantly higher rates of high serum creatinine. Hence, high serum creatinine may be one of the important factors of anemia in the elderly.

Aged↗

Hyperammonemic encephalopathy due to essential amino acid hyperalimentation.

Hyperammonemic encephalopathy has occasionally been reported in uremic patients receiving hyperalimentation with essential amino acid (EAA) as a source of nitrogen as one of the remaining treatment options when the enteric routes were prohibited. We encountered this complication in a patient with normal renal function. A rat animal model was designed to elucidate the mechanism of hyperammonemia resulting from hyperalimentation with EAA as a source of nitrogen. Sixty-four male Long-Evan rats were divided into eight groups receiving feeds ad libitum or different formula of hyperalimentation. Hyperammonemia was found in every rat given hyperalimentation with EAA as the only nitrogen source. Using the Tukey honestly significant difference test, the results were significantly higher (p < 0.001) than that of the control group which were given feeds ad libitum and those groups given hyperalimentation for the same number of days but with mixed amino acid (MAA) as the nitrogen source. Adding arginine to EAA for a further four days after initial administration of EAA hyperalimentation for three days only slightly lowered the mean serum ammonia level. When compared to that of the three-day EAA hyperalimentation group, the difference was not statistically significant. Adding arginine, citrulline, and ornithine to EAA for a further four days significantly lowered the mean serum ammonia level. When we changed EAA hyperalimentation to MAA hyperalimentation for a further four days, the mean serum ammonia level decreased dramatically to nearly normal. Hyperalimentation using EAA as the exclusive source of nitrogen resulted in hyperammonemia. A deficiency of arginine or other amino acids of the urea cycle failed to account completely for the hyperammonemia observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids, Essential↗

Study on the children of Kaohsiung with acute viral infection of lower respiratory tract by direct immunofluorescence assay.

This study retrospectively reviewed those pediatric patients of acute lower respiratory tract infection with positive virus identification by direct immunofluorescence assay (Direct IF) from Jan, 1992 to Dec, 1993. One hundred and eighteen patients with 133 positive Direct IF results (107 cases with single virus identified, and 11 cases with more than one) were included. The sex ratio was 1.6:1 with males predominant; age, 22.1 (1 approximately 154.8) (months); duration of admission, 5.7 (1 approximately 69) (days); peripheral white blood cell count, 10,600 +/- 3,800/mm3; C-reactive protein, 17.0 (0 approximately 163.3) mu/ml; body temperature, 37.1 +/- 1.1 degrees C in those cases with single virus. The symptoms were cough 105 cases (98.1%), rhinorrhea 46 cases (43.0%), dyspnea and/or tachypnea 43 cases (40.2%) and diarrhea 15 cases (14.0%). The viruses identified were: Adenovirus (52 cases, 39.1%). Influenza B (45 cases, 33.8%), Parainfluenza 1 (28 cases, 20.1%), Parainfluenza 3 (19 cases 14.3%), Respiratory Syncytial virus (17 cases, 12.8%), and Influenza A (9 cases, 6.8%). The seasonal incidence rates were spring (49 cases, 36.8%), summer (46 cases, 34.6%), autumn (23 cases, 17.3%), and winter (15 cases, 11.3%). The results showed much similarity with others, except the commonest viral type (Adenovirus in this study; Respiratory Syncytial virus in others) and the seasonal incidence rate (higher in spring and summer in this study but not in others). In conclusion, most children with acute viral lower respiratory tract infection had an uneventful course and Direct IF is a reliable method for viral detection in that disease.

Acute Disease↗

Apoptosis leads to photoreceptor degeneration in inherited retinal dystrophy of RCS rats.

PURPOSE: To determine the pathogenetic mechanism of photoreceptor cell degeneration in the inherited retinal dystrophy in Royal College of Surgeons (RCS) rats. METHODS: The dystrophic retinas of the pink-eyed RCS (RCS-rdy-p) rats were examined for DNA fragmentation by agarose gel electrophoresis of retinal DNA and by TdT-mediated biotin-dUDP nick-end labeling (TUNEL) in paraffin sections. Rats ranging in age from 3 to 60 days were examined. RESULTS: Agarose gel electrophoresis of retinal DNA isolated from animals 25, 30, 35, and 40 days old showed a ladder pattern of degradation with bands corresponding to multiples of 180 to 200 base pair subunits. TUNEL study showed increasing labeling of photoreceptor cells with progression of the retinal dystrophy of the RCS rats. CONCLUSIONS: Apoptosis is the dominant mechanism of photoreceptor degeneration in the RCS rat, which has a genetic defect in the phagocytic activity of retinal pigment epithelium. The onset of the degeneration appeared to vary between rod cells in the different regions of the eye.

Animals↗

Selective inhibition of the growth of ras-transformed human bronchial epithelial cells by emodin, a protein-tyrosine kinase inhibitor.

Emodin (3-methyl-1,6,8-trihydroxyanthraquinone), a naturally occurring protein-tyrosine kinase inhibitor, selectively blocked the growth of v-ras-transformed human bronchial epithelial cells. Half-maximal inhibition of cell growth occurred at a concentration of 4 micrograms/ml. In contrast, emodin at a concentration of 100 micrograms/ml had little effect on the growth of normal human bronchial epithelial cells. Cell cycle analyses indicated that treatment with emodin arrested the v-ras-transformed cells in the G2/M phase of their cell cycle. Immunoblotting experiments using anti-phosphotyrosine antibodies indicated that ras-transformed cells, as compared to their normal counterparts, exhibited elevated levels of phosphotyrosine-containing proteins. Treatment with emodin resulted in a decrease in intracellular protein-tyrosine phosphorylation. These results suggest that compounds that inhibit the ras-dependent elevation in the level of tyrosine phosphorylated proteins may prove to be useful chemotherapeutic agents and may exhibit selective cytotoxicity against cancer cells with an activated ras oncogene.

Bronchi↗

Dopamine metabolism and free-radical related mitochondrial injury during transient brain ischemia in gerbils.

Regional extracellular release of dopamine (DA) and its metabolites, 3,4-dihydroxy-phenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxytyramine (3-MT) was measured in gerbils (with or without pargyline pretreatment) subjected to bilateral carotid artery occlusion (15 min) and various periods of recirculation (up to 6 hr), utilizing intracerebral microdialysis and high-performance liquid chromatography (HPLC) with electrochemical detection. Mitochondrial monoamine oxidase (MAO) and superoxide dismutase (SOD) activities and in vitro stimulated lipid peroxidation (TBARM) were determined in separate experimental groups of animals. The ischemically induced DA release, decrease of MAO-derived DA metabolites DOPAC and HVA, and accumulation of 3-MT were potentiated and prolonged by pargyline pretreatment. Mitochondrial MAO and SOD activities were significantly reduced during ischemia alone and up to 1 hr of reperfusion, whereas TBARM was enhanced during reflow only. The data suggest that reduced activity of mitochondrial antioxidative enzyme(s) but not DA metabolism by MAO may contribute to free radical-mediated injury of (mitochondrial) membranes.

3,4-Dihydroxyphenylacetic Acid↗

Gossypol inhibits basal and estrogen-stimulated DNA synthesis in human breast carcinoma cells.

Estrogen stimulates the growth of hormone-dependent human breast cancer. Failure of chemotherapy frequently results from the development of multidrug resistance. Gossypol (GP), a naturally occurring toxin, inhibits the growth of various carcinoma cells. Thus, the effects of GP on 17 beta-estradiol (E2)-stimulated DNA synthesis were studied in two hormone-dependent human breast carcinoma cell lines: the wild-type MCF-7 and the multidrug-resistant MCF-7 Adr cells. Cells (5 x 104/well) were cultured for 24 hrs in a chemically-defined, serum-free medium consisting of 1:1 mixture of Dulbecco's Modified Eagle's medium and Ham's nutrient mixture F12 (DMEM/F12) supplemented with insulin (5.0 micrograms/ml), transferrin (5.0 micrograms/ml), epidermal growth factor (EGF; 10.0 ng/ml) and antibiotics E2 (0 or 10.0 nM), GP (0, 2.5, 5.0, 10.0 or 20.0 microM) and bovine serum albumin (BSA; 0 or 0.1 mg/ml) were used as treatments in a factorial experimental design. Cells were treated for 24 hrs and finally pulsed with 3H-thymidine (5.0 microCi/ml) for 3 hrs. E2 significantly stimulated 3H-thymidine incorporation in both MCF-7 and MCF-7 Adr cells. GP at 10.0 and 20.0 microM inhibited both basal and E2-stimulated DNA synthesis in human breast cancer cells. The inhibitory effects of GP at 10.0 microM, but not at 20.0 microM, were blocked by BSA treatment. Results from the present study indicate that GP treatment was antiproliferative in both drug-sensitive and multidrug-resistant cancer cells and that the antiproliferative effects of GP on human breast cancer cells were mediated through mechanisms independent of estrogenic responses. Thus, GP could be potentially very useful for treatment of human breast cancer patients, especially those who have developed multidrug resistance.

Breast Neoplasms↗

Evidence for a phosphoenolpyruvate dependent sugar-phosphotransferase system in the mollicute Acholeplasma florum.

In order to confirm the presence of a phosphoenolpyruvate (PEP)-dependent sugar-phosphotransferase system (PTS) in the mollicute Acholeplasma florum we studied the ability of cell free extracts of this organism to phosphorylate glucose and/or fructose in the presence of PEP. We also cloned and sequenced a DNA fragment coding for a putative polypeptide showing significant similarity with the enzyme II of the beta-glucoside PTS of Escherichia coli. Taken together, these results show that A florum possesses a fructose-PTS, but not a glucose-PTS, and that the amino acid sequence deduced from the DNA fragment is related to beta-glucoside and sucrose enzymes II of PTS from various bacteria.

Acholeplasma↗

Differences in precision of dietary estimates among different population subgroups.

Populations vary in consistency of diets. The precision of estimates (E) of nutrient intake depends both on the ratio (R) of intraindividual to interindividual variances, as well as on the number of days of dietary intake recorded (k). We present baseline data from 872 participants in the Trial of Antihypertensive Interventions and Management (TAIM), a randomized clinical trial of diet and drug treatment for mild hypertension. There is wide variation in R among different demographic groups and for different nutrients. This has implications for the ability to estimate the correlations between the nutrient and a physiologic variable such as blood pressure, as well as for power calculations to compare group means on nutrient intake. For example, to achieve the same degree of precision (E = 0.80) in estimating the correlation between sodium intake and blood pressure for whites in New York, 7 days of food records would be required, compared to 2 days for whites in Alabama. Tables are presented indicating within- and between-person variances for different groups and different nutrients. Methods of calculating E, determining k, and calculating samples size are provided. Investigators designing nutritional epidemiologic studies should take into account ratios of intraindividual to interindividual variances of different population subgroups and different nutrients in order to determine the number of daily food records that must be obtained and the sample size for group comparisons.

Adult↗

Flavonoids from Koelreuteria henryi and other sources as protein-tyrosine kinase inhibitors.

The EtOH extract of Koelreuteria henryi was investigated in a search for natural products with potential protein-tryrosine kinase (PTK) inhibitory activity. The PTK inhibitory activity of the crude fractions was determined by measuring their inhibition of p56lck partially purified from bovine thymus using angiotensin I as a substrate. Analysis of those fractions that exhibited significant activity led to the isolation of kaempferol and quercetin, in addition to two kaempferol glycosides, kaempferol-O3-alpha-rhamnopyranoside [1] and kaempferol-O3-alpha-arabinopyranoside [2]. This study represents the first report on the isolation of flavonols and their PTK inhibitory activities from the genus Koelreuteria. Eight other flavonoids were also examined to study the role of the hydroxy groups on the B ring on PTK inhibitory activity.

Animals↗

Kinase inhibitors from Polygonum cuspidatum.

Bioassay-directed fractionation of a medicinal plant, Polygonum cuspidatum (Polygonaceae), has led to the discovery of a hydroxystilbene, resveratrol [1], as an inhibitor of a protein-tyrosine kinase (p56lck) partially purified from bovine thymus. Both trans and cis isomers of resveratrol possess comparable protein-tyrosine kinase inhibitory activity. Comparison of the IC50 values of resveratrol for protein-tyrosine kinase inhibitory activity with those of piceid (resveratrol-O3-beta-glucoside) [2] and resveratrol-O4'-beta-glucoside [3] shows the requirement of free hydroxyl groups on both phenyl rings for the protein-tyrosine kinase inhibition. Protein kinase C inhibitory analysis suggests the requirements of two free hydroxyl groups on one phenyl ring only.

Animals↗

Solid-state nuclear magnetic resonance (NMR) spectra of pharmaceutical dosage forms.

Solid-state 13C NMR spectra of tablets or capsules of prednisolone, enalapril maleate, lovastatin, simvastatin, ibuprofen, flurbiprofen, mefenamic acid, indomethacin, diflunisal, sulindac, and piroxicam were obtained in the CP/MAS mode at 50 MHz. These studies show that (1) solid-state NMR spectroscopy can detect the active ingredients in low-dose tablets and capsules; (2) the use of interrupted decoupling often results in suppression of resonances due to excipients, thereby allowing better detection of resonances from the drug; and (3) the technique permits discrimination between two prednisolone polymorphs present in tablets obtained from various manufacturers even though the tablets contain only approximately 5% (w/w) of the drug.

Anti-Inflammatory Agents, Non-Steroidal↗

Effects of cerebral ischemia on regional dopamine release and D1 and D2 receptors.

To expand on the nature of regional cerebral vulnerability to ischemia, the release of dopamine (DA) and dopaminergic (D1 and D2) receptors were investigated in Mongolian gerbils subjected to bilateral carotid artery occlusion (15 min) alone or with reflow (1-2 h). Extracellular cortical and striatal content of DA and its metabolites was measured by microdialysis using HPLC with electrochemical detection. The kinetic properties of D1 and/or D2 receptor binding sites were determined in cortical and striatal membranes with the use of radiolabeled ligands (125I-SCH23982 and [3H]YM-09151-2, respectively). The ischemic release of DA from the striatum was greater (400-fold over preischemic level) than that from the cortex (12-fold over preischemic content). The affinity for the D1-receptor ligand was lower (KD = 1.248 +/- 0.047 nM) after ischemia than that for sham controls (KD = 0.928 +/- 0.032 nM, p < 0.001). The number of binding sites for D2 receptors decreased in striatum (Bmax = 428 +/- 18.4 fmol/mg of protein) after ischemia compared with sham controls (Bmax = 510 +/- 25.2 fmol/mg of protein, p < 0.05). D1 or D2 binding sites were not changed either in the ischemic cortex or postischemic striatum and cortex. The findings strongly suggest that the ischemic release of DA from striatum is associated with early transient changes in D1- and D2-mediated DA neurotransmission.

3,4-Dihydroxyphenylacetic Acid↗

The antitachycardia pacing ICD: impact on patient selection and outcome.

UNLABELLED: Implantable cardioverter defibrillators (ICD) currently undergoing clinical investigation incorporate antitachycardia pacing capabilities, but little is known about their effect on patient selection and outcome. The Bilitch registry database was reviewed to compare the 1,553 patients who initially received standard devices with the 242 patients initially implanted with antitachycardia pacing ICDs (ANT). Baseline characteristics including mean age, ejection fraction, sex, type of cardiac disease, and percent presenting with sudden cardiac death were reviewed. Cumulative first shock occurrence and survival from arrhythmic and all cause mortality were calculated for the two groups. RESULTS: Patient characteristics were similar in the two groups except that the ANT population had a greater male predominance and initially presented with a lower sudden cardiac death incidence (P < 0.05). Cumulative occurrence of first shock was significantly lower in the ANT group up to 24 months of follow-up (28% vs 36%, P < 0.05). ANT group survival from arrhythmic death (99% vs 96%) and all cause mortality (89% vs 94%) was significantly higher at 24 months of follow-up (P < 0.05). CONCLUSIONS: The addition of antitachycardia pacing to ICD therapy appears to significantly limit the occurrence of first ICD shock without adversely affecting mortality in a patient population similar to those implanted with standard ICDs.

Death, Sudden, Cardiac↗

Development of macrovascular diseases in NIDDM patients in northern Taiwan. A 4-yr follow-up study.

OBJECTIVE: To assess the development of macrovascular diseases and explore major associative factors in NIDDM. RESEARCH DESIGN AND METHODS: A total of 479 NIDDM patients > or = 40 yr of age were recruited from four community primary care health centers of northern Taiwan in July 1986 for a cohort study with a 4-yr follow-up. No patient required insulin therapy within 1 yr of diagnosis nor had a history of diabetic ketoacidosis. All were able to participate independently in the activities of daily living. BP and ECG were measured, and a structured questionnaire was asked of each patient. Venous blood after overnight fasting was collected every year to measure cholesterol, HDL cholesterol, plasma glucose, and HbA1c. RESULTS: The duration of diabetes was associated with the development of stroke with a relative risk of 1.063 for every 1-yr increment (P = 0.07). As for HVDs, the significant risk factors were serum cholesterol and HbA1c. For every 1-mg/dl increase in mean total cholesterol level, the relative risk of developing HVD increased 1.016-fold (P = 0.04). For every 1% increase in HbA1c, the relative risk of developing HVD increased 1.170-fold (P = 0.01). With regard to leg VDs, sex and cigarette smoking were significant risk factors. Women diabetic subjects had a higher relative risk than men. Cigarette smoking was significantly associated with leg VD with a relative risk of 6.9 for smokers compared with nonsmokers. The most significant risk factor for LVD was the total cholesterol level. For every 1-mg/dl increase in mean serum cholesterol level, the relative risk of LVD increased 1.013-fold. CONCLUSIONS: In the prevention of macrovascular diseases, effective intervention of the nondiabetic cardiovascular risk factors may be as important as or even more important than the good control of diabetes.

Adult↗

Lumbosacral kinematics in the sagittal plane: a radiographic study in vivo.

Lateral functional radiographs of flexion and extension using Putto's method were examined in 89 normal subjects. A specially-designed radiopaque ruler was placed on each film for calibration. A computer-assisted method was used for digitization and analysis. There were weak negative correlations between age and range of motion, especially at the L4-L5 level (r = 0.437). No significant correlation was noted between age and translation. For flexion-extension rotation, although large variations may limit its usefulness in judging instability in some clinical settings, the data still provide a good diagnostic basis. For translation changes, 2 mm is regarded as acceptable in most cases at levels from L1 to L5, but not at the level of L5-S1 where the average translation change was only 0.4 mm. The differences in the absolute translation value among different positions were not statistically significant (p = 0.064).

Adult↗