Biomedical subjects

C J Chang

Publications and source records attributed to C J Chang.

At least 127 records · Page 7Linked to original sources

PubMed1997

Multidrug-resistance modulators from Stephania japonica.

An alkaloidal extract of the vines of Stephania japonica showed multidrug-resistance-reversing activity as demonstrated by the bicinchoninic acid assay. Two known bisbenzylisoquinoline alkaloids, isotrilobine (1) and trilobine (2), were isolated by bioassay-directed fractionation and separation. Isotrilobine (1) was shown to be as active as verapamil (3) in reversing doxorubicin resistance in human breast cancer cells.

Antineoplastic Agents, Phytogenic↗

PubMed1997

Laser intraductal photocoagulation of bilateral parotid ducts for reducing drooling of cerebral palsied children: a preliminary report.

Previous reports suggested that surgical treatment was effective to reduce abnormal, profuse drooling in children with low cognitive function, but with risk of complications. Laser photocoagulation might be an option to simplify the procedure and decrease complications. Our study considered whether laser photocoagulation could improve drooling in children with cerebral palsy (CP). CP children with drooling were recruited from the pediatric rehabilitation clinic, all of whom had persistent profuse drooling after 6 months of conservative treatment. They received neodymium:yttrium aluminum garnet (Nd:YAG) laser for intraductal photocoagulation to bilateral parotid ducts, and were followed up for 2 to 3 months. Each patient was assessed before and after the procedure by: 1) questionnaire-based semiquantitative assessment of drooling severity and frequency (Thomas-Stonell and Greensberg 1988); 2) quantitative assessment of saliva amount by collection of stimulated saliva for 2 minutes in cooperative children. Six CP children with severe drooling received laser photocoagulation, five of them had remarkable decrease of drooling 1 month later. Patients had cool liquid intake soon after the procedure, and were discharged on the second day after treatment. A period of transient face swelling ranged from 6 to 37 days. No antibiotic treatment was indicated nor were any complications noted after the procedure. As a result of these studies, it is suggested that laser intraductal photocoagulation of bilateral parotid duct could be used as a simple and effective procedure for reducing drooling in CP children, and would avoid complications from conventional surgery.

Cerebral Palsy↗

PubMed1997

Pilot in vitro toxicity study of 5-ALA and Photofrin in microvascular endothelial cell cultures.

Complicated hemangiomas are unique problems in which intervention with the proper laser can be an ideal solution. In this study we evaluated the toxicity of 5-Aminolevulinic acid (5-ALA) and Photofrin using in vitro models. The in vitro toxicity of 5-ALA and Photofrin was examined in a microvascular endothelial cell (MEC) culture system. The measurement of the percentage of MEC killed by various drug concentration using fluorescence viability assay. MEC incubated with 5-ALA at various concentrations for evaluation of dark toxicity showed less than a 50% cell kill. A comparison of different intervals of subcultured MEC showed that the early subculture (3 days after primary culture) is more vulnerable than later subculture (7 days after). Cells treated with Photofrin at various concentrations exhibited less than 50% cell kill (dark toxicity). The comparison of different intervals of subculture (3 days and 7 days after primary culture) showed a result similar to that of 5-ALA. All controls showed 0% cell kill. In conclusion, both 5-ALA and Photofrin are capable of destroying human microvascular endothelial cells in vitro. Drug concentrations and the power density for photodynamic therapy should be considered and will be included in our subsequent studies.

Aminolevulinic Acid↗

PubMed1997

Transcriptional induction of the agp/ebp (c/ebp beta) gene by hepatocyte growth factor.

Hepatocyte growth factor (HGF) is a pleiotropic factor with mitogenic, morphogenic, motogenic, cytotoxic, or growth inhibitory activity. Although the signaling of HGF is mediated through the cell membrane receptor c-Met, the molecular mechanism of downstream signal transduction remains obscure. In this report, we present evidence that shows HGF can stimulate the expression of AGP/EBP (C/EBP beta) and NF-kappaB, which are both key transcription factors responsible for the regulation of many genes under stress conditions or during the acute-phase response. Biochemical and functional analysis indicates that the HGF-responsive element is located in the region -376 to -352 (URE1) of the 5'-upstream regulatory sequence of agp/ebp. Activation of NF-kappaB by HGF was observed to precede the induction of agp/ebp. Further studies indicate that NF-kappaB can cooperate with AGP/EBP or other members of the C/EBP family to activate the agp/ebp gene in both URE1 and URE2-dependent manner. These results suggest that the induction of the agp/ebp gene by HGF is mediated at least in part by its activation of NF-kappaB. The activated NF-kappaB then interacts with AGP/EBP, resulting in the induction of agp/ebp.

Animals↗

PubMed1997

Reconstruction of head and neck hemangiomas with tissue expansion in the pediatric population.

A retrospective study of 245 patients with 299 hemangiomas treated from May 1981 to April 1994 was done. A subset of 175 of these patients (58.5%) had hemangiomas of the head and neck. Six of the 175 (3%) required reconstruction following laser therapy. Tissue expansion was chosen for each of these reconstructions. Five females and 1 male underwent tissue expansion. The age of the patients at the time of tissue expansion ranged from 2.5 to 12 years, with an average of 6 years. Tissue expander sizes were 50 cc and 100 cc. Infection was seen during the course of expansion in 1 patient. Satisfactory results were achieved after reconstruction in all cases. Tissue expansion is the treatment of choice for reconstruction of head and neck hemangioma deformities following laser or other surgical procedures as well as involution.

Child↗

PubMed1997

Management of hemangioma of infancy: review of 245 patients.

A retrospective study of patients treated from May of 1981 to April of 1994 was conducted. A total of 245 patients with 299 hemangiomas were studied, which represents the largest series reported to date. The study consisted of 173 females and 72 males ranging in age from 1 day to 59 years, with the average age being 4 years and 7 months. Twenty-six were premature neonates (14 females and 12 males). An interesting finding was a 1:1 sex ratio among this group in contrast to the 3:1 female-male ratio frequently reported in the literature. Onset was at birth in 170, within the first month in 43, and after the age of 1 month in 32 patients. Among the 245 patients, 175 hemangiomas were located on the head and neck, 62 on the trunk, 49 on the extremities, and 13 in the perineal area. Five groups of patients were defined based on clinical management. As a result, these groups are not similar. The five groups are as follows: group I (48), observation; group II (9), steroid treatment; group III (27), excision and reconstruction; group IV (88), laser therapy; and group V (73), combined therapy. The involved area of hemangioma was as follows: group 1, 0.5 x 0.5 to 20 x 8 cm; group II, 2 x 2 to 8 x 8 cm; group III, 0.4 x 0.8 to 7 x 7 cm; group IV, 0.5 x 0.5 to 20 x 9 cm; and group V, 1.5 x 1.5 to 25 x 25 cm. The complications of hemangioma seen at the time of consultation were obstruction (28.6 percent), ulceration (20.4 percent), bleeding (14.7 percent), infection (4.9 percent), and pain (0.4 percent). Treatment periods ranged from 1 month to 11 years, with the mean period in each group as follows: group I, 4 years and 9 months; group II, 2 years and 5 months; group III, 1 year and 1 month; group IV, 2 years and 1 month; and group V, 3 years. The outcomes of each patient were evaluated based on improvement of volume, color, and texture by the following scale: 1, poor (0 to 25 percent); 2, fair (26 to 50 percent); 3, good (51 to 75 percent); and 4, excellent (76 to 100 percent). Each of these parameters was summarized for each of the five groups. Statistical analysis by the Irwin-Fisher test was used for analysis and comparison of the final results between groups. Statistically significant differences in outcomes between treatment groups were demonstrated. Laser therapy was shown to be statistically superior to observation with regard to length of treatment and with regard to outcomes of volume and texture (p < 0.05).

Adolescent↗

PubMed1997

PCR detection of human papillomavirus: comparison between MY09/MY11 and GP5+/GP6+ primer systems.

Human papillomavirus (HPV) is an etiologic agent of cervical cancer and is the most common sexually transmitted disease in women. PCR amplification of HPV genomes is the most sensitive method for the detection of cervicovaginal HPV. We have compared the two most commonly used PCR primer sets, MY09/MY11 (MY-PCR) and GP5+/GP6+ (GP+-PCR), for the detection of HPV DNA in cervicovaginal lavage samples from 208 women. Oligonucleotide probes for 39 different HPV types were used. Both primer sets amplified a wide spectrum of HPV genotypes and detected similar overall prevalences of 45% (94 of 208) and 43% (89 of 208), respectively. The MY-PCR system detected 27 of 30 (90%) samples with multiple HPV types, whereas the GP+-PCR system detected 14 of 30 (47%) samples with multiple HPV types. Differences in the detection of HPV types 35, 53, and 61 were noted between the two primer systems. Serial dilution of plasmid templates indicated a 3-log decrease in the amplification of HPV type 35 by MY-PCR and HPV types 53 and 61 by GP+-PCR. These results indicate that although the MY-PCR and GP+-PCR identified nearly equivalent prevalences of HPV in a set of clinical samples, differences in the detection of specific types and infections with multiple types were found. Differences in the sensitivities and characteristics of the PCR systems for the detection of HPV within clinical samples should be considered when comparing data between studies and/or in designing new studies or clinical trials.

DNA Primers↗

PubMed1997

Identification and characterization of a nucleolar phosphoprotein, Nopp140, as a transcription factor.

Expression of the alpha-1 acid glycoprotein (AGP) gene (agp) is activated by a key transcription factor, AGP/enhancer-binding protein (AGP/EBP, commonly called C/EBP beta), in the liver during the acute-phase response. In addition to this positive regulation, agp is negatively regulated by nucleolin (T. H. Yang et al., Mol. Cell. Biol. 14:6068-6074, 1994). Other factors involve in positive regulation of the agp gene are poorly characterized. In a systematic search for factors that may interact with AGP/EBP, we have identified Nopp 140, a phosphoprotein of 140 kDa, by immunoaffinity chromatography. Nopp 140 not only functions as a transcriptional activator per se but also interacts with AGP/EBP to synergistically activate the agp gene in an AGP/EBP-binding motif-dependent manner. In addition to interacting with AGP/EBP, Nopp140 interacts specifically with TFIIB. Distinct regions of Nopp140 that interact with AGP/EBP and TFIIB have been characterized. The sequence of Nopp140 contains several stretches of serine- and acidic amino acid-rich sequences which are also found in ICP4 of herpes simplex virus type 1, a known transcription factor that interacts with TFIIB. The physical interaction between TFIIB and wild-type Nopp140 or several deletion mutants of Nopp140 correlates with the ability of Nopp140 to activate the agp gene synergistically with AGP/EBP. Thus, the molecular mechanism for agp gene activation may involve the interaction of AGP/EBP and TFIIB mediated by coactivator Nopp140.

Amino Acid Sequence↗

PubMed1997

Age and sex effects on HbA1c. A study in a healthy Chinese population.

OBJECTIVE: To evaluate whether glycohemoglobin levels increase with age in both sexes and to determine the effect of BMI on this increment. RESEARCH DESIGN AND METHODS: A cross-sectional survey of 4,580 healthy Chinese men and women, aged 20-85 years, was performed. All subjects who did not have identifiable diseases and who were not on medication known to influence glucose tolerance were recruited from participants at the preventive services of the National Cheng-Kung University Hospital. As an indicator of plasma glucose levels, glycohemoglobin was measured. The subjects were classified according to their age and BMI for both men and women, and any relationships with glycohemoglobin levels were evaluated. RESULTS: In all the BMI groups divided into quartiles, glycohemoglobin levels increased with age. The largest elevation of glycohemoglobin was observed in the 45- to 54-year-old age-group, except in men with a BMI between the lowest and highest quartiles. The group with a BMI above the highest quartile had a higher glycohemoglobin than the group with a BMI below the lowest quartile in men aged < 54 years and women aged 35-64 years. Men had higher average glycohemoglobin levels than women < 55 years of age. CONCLUSIONS: The age factor itself may cause an elevation in glycohemoglobin independent of other age-related factors in Chinese men and women, and there is a sex difference with a lower average glycohemoglobin level in women before menopause. Furthermore, BMI, but not a family predisposition to diabetes or leisure-time physical activity, affects this age-dependent increase in glycohemoglobin levels.

Adult↗

PubMed1997

Urinary estrogen metabolites and breast cancer: a case-control study.

Preliminary studies suggest that the estrogen metabolite 16 alpha-hydroxyestrone is associated with breast cancer, whereas 2-hydroxyestrone is not. However, epidemiological studies evaluating this relationship and taking established risk factors for breast cancer into account are lacking. The purpose of this study was to examine the association of the ratio of the urinary estrogen metabolites (2-hydroxyestrone and 16 alpha-hydroxyestrone) and of the individual metabolites with breast cancer. A spot urine sample, a brief history, and clinical data were collected from breast cancer cases (n = 42) and from women coming to the hospital for a routine mammogram or attending a free breast cancer screening (n = 64). 2-Hydroxyestrone and 16 alpha-hydroxyestrone were measured by enzyme immunoassay, and the estrogen metabolite ratio (EMR; 2-hydroxyestrone:16 alpha-hydroxyestrone) was computed. Cases and controls were similar in terms of age (mean age of cases, 53.8 +/- 15.1 years, versus 54.2 +/- 10.4 years for controls; P = 0.9) and demographics. Mean EMR was not associated with breast cancer overall (1.67 +/- 0.80 versus 1.72 +/- 0.66; P = 0.7). However, in postmenopausal women, the mean EMR was significantly lower in cases compared to controls (1.41 +/- 0.73 versus 1.81 +/- 0.71; P = 0.05). The multivariate adjusted odds ratios for the intermediate and lowest tertiles of the EMR relative to the highest among postmenopausal women were 9.73 (95% confidence interval, 1.27-74.84) and 32.74 (95% confidence interval, 3.36-319.09), respectively. The test for trend was highly significant (P = 0.003). Analyses of the individual metabolites indicated that 16 alpha-hydroxyestrone was a strong risk factor. The EMR did not show any consistent associations with age, race/ethnicity, age at first birth, parity, body mass index, family history of breast cancer, smoking, or alcohol intake. These data suggest a strong, inverse association of the EMR and a strong positive association of 16 alpha-hydroxyestrone with breast cancer in postmenopausal women. Larger studies are needed to confirm these results and to assess the relationship of the EMR and of the individual metabolites with breast cancer, with attention to menopausal status and clinical factors and with adjustment for known breast cancer risk factors.

Adult↗

PubMed1996

Comparison of isoproterenol with BRL37344 in activation of beta 3-adrenoceptors to inhibit the uptake of [14C]deoxy-D-glucose and translocation of glucose transporter (GLUT4) to membrane fraction in rat adipocytes.

In an attempt to understand the role of beta 3-adrenoceptors in the regulation of glucose uptake, the effect of isoproterenol was compared with BRL37344 in isolated white adipocytes of the rat using [14C]deoxy-D-glucose as an indicator. In the presence of BRL37344, the specific agonist of beta 3-adrenoceptors, spontaneous uptake of [14C]deoxy-D-glucose (glucose uptake) into adipocytes was markedly attenuated. Similar concentration-dependent inhibition of glucose uptake was also observed in the samples treated with isoproterenol, an agonist for all kinds of beta-adrenoceptors. Action of BRL37344 was blocked by propranolol at concentrations sufficient to abolish the activity of isoproterenol. Pindolol reversed BRL37344-induced inhibition more effectively than propranolol. Moreover, unlike the action of isoproterenol, BRL37344 did not modify the insulin-stimulated glucose uptake. Translocation of glucose transporter (GLUT4) from cytosol to membrane stimulated with insulin was reduced by isoproterenol but not by BRL37344. Combination with the findings that isoproterenol prolonged the time for insulin to reach maximum stimulation of glucose uptake, leads to the conclusion that delay of insulin action by isoproterenol can be considered as one of the mechanisms for this inhibition. The results obtained suggest that BRL37344 decreased the spontaneous uptake of glucose via an activation of beta 3-adrenoceptors while the insulin stimulated glucose uptake was inhibited by isoproterenol but not by BRL37344.

Adipocytes↗

PubMed1996

A new method for estimating high mutation rates in cultured cells.

Fluctuation analysis allows for the determination of mutation rates in cell cultures in vitro. As originally described by Luria and Delbruck and extended by Lea and Coulson and by Capizzi and Jameson, this analysis has been useful in estimating mutation rates in cultured cells where the frequency of mutational events is low. However. in cultures where high mutation rates and multiple independent mutation events occur, leading to the accumulation of many mutant cells, these standard methods may not apply. Here, we present a new method for the estimation of mutation rates based on the assumption that multiple events may contribute to the accumulation of mutant cells. We compared mutation rates determined by Lea and Coulson's and by Capizzi and Jameson's methods with those determined by our method using experimental and stimulated data from our studies of immunoglobulin gene mutation and isotype switching in B lymphocyte cultures. The three methods resulted in very different calculated rates when many mutants were present in the culture, such as when mutation rates were high, while only small differences in calculated rates were found when mutants were rare. Unlike previous fluctuation analysis calculations, our method is applicable for the estimation of both low and high rates.

Animals↗

PubMed1996

Change in depression as a precursor of cardiovascular events. SHEP Cooperative Research Group (Systoloc Hypertension in the elderly).

OBJECTIVE: To determine the relationship between increasing depressive symptoms and cardiovascular events or mortality. DESIGN: Cohort analytic study of data from randomized placebo-controlled double-blind clinical trial of antihypertensive therapy. Depressive symptoms were assessed semi-annually with the Center for Epidemiological Studies-Depression (CES-D) scale during an average follow-up of 4.5 years. SETTING: Ambulatory patients in 16 clinical centers of the Systolic Hypertension in the Elderly Program. PATIENTS: Generally healthy men and women aged 60 years or older randomized to active antihypertensive drug therapy or placebo who were 70% white and 53% women and had follow-up CES-D scores and no outcome events during the first 6 months (N=4367). MAIN OUTCOME MEASURES: All-cause mortality, fatal or nonfatal stroke, or myocardial infarction. RESULTS: Baseline depressive symptoms were not related to subsequent events; however, an increase in depression was prognostic. Cox proportional hazards regression analyses with the CES-D scale as a time-dependent variable, controlling for multiple covariates, indicated a 25% increased risk of death per 5-unit increase in the CES-D score (relative risk [RR], 1.25;95% confidence interval [CI], 1.15 to 1.36). The RR for stroke or myocardial infarction was 1.18(95%CI,1.08 to 1.30). Increase in CES-D score was an independent predictor in both placebo and active drug groups, and it was strongest as a risk factor for stroke among women (RR,1.29;95%CI,1.07 to 1.34). CONCLUSIONS: Among elderly persons, a significant and substantial excess risk of death and stroke or myocardial infarction was associated with an increase in depressive symptoms over time, which may be a marker for subsequent major disease events and warrants the attention of physicians to such mood changes. However, further studies of casual pathways are needed before wide-spread screening for depression in clinical practice is to be recommended.

Aged↗

PubMed1996

The G1691A mutation of the coagulation factor V gene (factor V Leiden) is rare in Chinese: an analysis of 618 individuals.

To understand the allele frequency of the G1691A mutation of the coagulation factor V gene (factor V Leiden) in Chinese, 618 Chinese individuals, including 54 cases with venous thrombosis, were analyzed. Only one case in the control group was heterozygous for the 1691G allele and the 1691A allele. Our data suggest that the factor V Leiden is rare in Chinese.

Alleles↗

PubMed1996

Factors associated with orthostatic hypotension in the Chinese population in Taiwan.

Factors associated with orthostatic hypotension are heterogeneous, and some of the factors are interrelated and interdependent, which may confound their relationships to orthostatic hypotension. To investigate the factors that were most likely related to orthostatic hypotension, a study of community-dwelling persons (419 men and 309 women) was conducted. Blood pressures and heart rates were measured after the subjects had been recumbent for 5 min and upright for 1 min. A total of 119 persons (16.3%) experienced orthostatic hypotension. Univariate analysis showed that orthostatic hypotension was associated with the following variables: hypertension, diabetes mellitus, cerebrovascular disease, proteinuria, abnormal renal function, or medications use. Those patients with orthostatic hypotension were older in age and had a higher body mass index, seated blood pressure, plasma creatinine, hemoglobin A1c, fasting and 2-h postload glucose levels than those without orthostatic hypotension. Multivariate analysis revealed that diabetes mellitus, hypertension, and age were independently associated factors for orthostatic hypotension. The higher the level of plasma hemoglobin A1c (%) elevation, the higher the likelihood of orthostatic hypotension manifestation. Clinically, elderly persons or patients with hypertension or diabetes mellitus should receive regular monitoring of supine and upright blood pressure in order to detect orthostatic hypotension and prevent its complications.

Adult↗

PubMed1996

Month of birth and schizophrenia in Taiwan: effect of gender, family history and age at onset.

Schizophrenic patients have been shown to have a moderate excess of winter births in the areas where seasonal variations in weather are large. In this report, we examined the seasonality of schizophrenic births in Taiwan, which has a subtropical climate. Using nationwide hospitalization data (2429 male and 1320 female schizophrenic patients), we applied the life table method to compare the risk of schizophrenia among 12 cohorts of month-of-birth for males and females, respectively. Differences among the risks of the 12 cohorts were tested using the logrank test. The samples were further stratified by family history and age at onset. There was a significant association between the risk of being admitted as a schizophrenic and month of birth for both males and females. The cohorts born in November and January had the highest risks. After stratification, the association was significant only for non-familial, male, and early onset schizophrenic patients. The results indicate that seasonally varying factors might increase the risk of schizophrenia, especially in those without a family history of the disease. Men are more vulnerable to such factors than women, and the schizophrenics resulting from such insults tend to be early onset.

Adolescent↗

PubMed1996

Implications of urinary basic fibroblast growth factor excretion in patients with urothelial carcinoma.

1. Angiogenesis occurs in response to wounding, and is of vital importance for tumour growth and metastasis. Basic fibroblast growth factor, a well-known angiogenic factor, has been suggested to be a urine marker for urothelial carcinoma. However, the relevance of its detection has not been evaluated in a large number of patients. 2. Immunoassay of basic fibroblast growth factor was performed on urine samples from different aetiologies of urothelial disorder. Expression of basic fibroblast growth factor in the corresponding tumour was correlated with the urine level. 3. The excretion of basic fibroblast growth factor (ng/g creatinine) was significantly elevated in both inflammatory and neoplastic urological diseases compared with normal individuals (P < 0.05), while it was normalized in tumour-free subjects (P < 0.01). Receiver operating characteristic plotting revealed a sensitivity of 40% for tumour diagnosis at the cut-off point of 3.29 ng/g creatinine. The sensitivity of the test in predicting tumour recurrence was only 14%. The basic fibroblast growth factor level in urine showed a positive association with increasing age of cancer patients (P = 0.02) and with tumour grading (P = 0.05). However, no important relationship was observed regarding tumour stage, size, number, shape or degree of local inflammatory reaction (P > 0.01). Pairwise analysis of the basic fibroblast growth factor level in urine and its expression in corresponding tumours did not reveal a conspicuous correlation (r = -0.097, P = 0.43). 4. Our results suggested that estimation of urinary basic fibroblast growth factor cannot be satisfactory as a tumour marker. The measurement may represent one of the tissue responses to injury or the host-tumour interactions. A longitudinal study is required to elucidate the role of basic fibroblast growth factor in order to select the appropriate treatment strategy for urothelial carcinoma.

Adult↗

PubMed1996

Q-switched ruby laser treatment of mucocutaneous melanosis associated with Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome is an eponym for circumscribed mucocutaneous melanosis in association with gastrointestinal polyposis. Irregular pigmented macules of varying size and color can be found on the perioral skin, lip vermillion border, buccal mucosa, palate, and tongue. Previous treatments, such as surgical excision, cryosurgery, electrodesiccation, dermabrasion, and carbon dioxide or argon laser ablation commonly result in incomplete removal, scarring, or changes in normal pigmentation. The Q-switched ruby laser used at 694 nm, a wavelength well absorbed by melanin relative to other optically absorbing structures in skin, causes highly selective destruction of pigment-laden cells. In addition, the 20-nanosecond pulse duration produced by this laser approximates the thermal relaxation time for melanosomes, thereby confining the energy to the target. The Q-switched ruby laser produces clinically significant fading of mucocutaneous melanosis in association with Peutz-Jeghers syndrome without complications often seen with other therapeutic modalities.

Adolescent↗