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Biomedical subjects

C L Chang

Publications and source records attributed to C L Chang.

At least 19 recordsLinked to original sources
PubMed2000

Steady-state regulation of the human DNA mismatch repair system.

Steady-state levels of human DNA mismatch repair (MMR) transcripts and proteins were measured in MMR-proficient and -deficient cell lines by the newly developed competitive quantitative reverse transcription- polymerase chain reaction and Western analysis normalized with purified proteins. In MMR-proficient cells, hMSH2 is the most abundant MMR protein and is expressed 3 to 5 times more than hMLH1. The hMLH1 protein was expressed 1.5 to 2.5 times more than hPMS2. Steady-state levels of mRNA expression correlated well with protein expression. hMSH2-mutated LoVo cells did not express detectable hMSH3 or hMSH6 proteins. Similarly, hMLH1-mutated HCT116 cells did not express detectable hMLH1 or hPMS2 protein, whereas in hMLH1-restored HCT116+ch3 cells, hPMS2 protein was re-expressed. In hMSH6-mutated HCT15 cells, both hMSH3 protein and mRNA were increased. In SV40-transformed lung fibroblasts, all MMR mRNAs and proteins examined were expressed at levels 1.5-5-fold higher than in their nontransformed counterpart. The steady-state levels of MMR proteins indicate that substantially more hMutS proteins, which are involved in DNA mismatch recognition, are present in comparison with the hMutL proteins. Stability of hMSH3 and hMSH6 proteins appears to depend upon the presence of the hMSH2 protein, and, similarly, the stability of the hPMS2 protein depends upon hMLH1. When the hMSH6 is mutationally inactivated, hMSH3 increases by both transcriptional up-regulation and enhanced protein stability. A balanced up-regulation of all of the components was seen after viral transformation in a fibroblast model. Quantitative changes of the MMR components are a potential mechanism to modify the DNA MMR capabilities of a cell.

Cell Transformation, Viral↗
PubMed2000

Spleen laceration, a rare complication of laparoscopy.

A 31-year-old woman had secondary infertility of 4 years' duration. Hysterosalpingography revealed bilateral distal tubal occlusion with bilateral hydrosalpinx-like appearance. At laparoscopy, both oviducts were occluded with marked hydropic change. Salpingoplasty was performed to correct bilateral hydrosalpinges and reform the fimbriated tubal ends. The procedure was performed uneventfully by an experienced surgeon in 45 minutes. Nine hours after the operation an emergency exploratory laparotomy was performed due to massive intraabdominal bleeding. The cause was a small tear, 3 cm long and 1 cm deep, with active bleeding in the inferior splenic tail. The laceration was repaired successfully with 1-0 chromic suture. The etiology of splenic laceration during laparoscopic surgery is uncertain. Many complications of laparoscopy are physiologic, and this one might have occurred while establishing pneumoperitoneum. Distortion and stretching of small vascular adhesions of the spleen with the abdominal wall also may have played a role. Gynecologists must be aware of the physiologic insult to patients during laparoscopy.

Adult↗
PubMed2000

Acute cerebral phaeohyphomycosis due to Wangiella dermatitidis accompanied by cerebrospinal fluid eosinophilia.

We report a case of cerebral phaeohyphomycosis due to Wangiella dermaitidis in an immunocompetent adult man. His cerebrospinal fluid (CSF) showed pleocytosis with a high eosinophil count but without peripheral blood eosinophilia. The present case suggested that this black yeast-like fungus should be included when the causes of CSF eosinophilia are considered, even though it is an extremely rare pathogen.

Adult↗
PubMed1999

Association between birth weight and adult blood pressure in twins: historical cohort study.

OBJECTIVES: To evaluate the associations in twins between within pair differences in birth weight and subsequent blood pressures as adults thereby removing the impact of potential parental confounding variables. DESIGN: Historical cohort study. SETTING: St Thomas's UK adult twin register, June 1992 to September 1995. PARTICIPANTS: 492 pairs of female twins (mean age 54 years). MAIN OUTCOME MEASURES: Mean within pair differences in adult blood pressure in each of four strata of within pair differences in birth weight (0, 1-500 g, 501-1000 g, >1000 g). Differences in blood pressure were analysed before and after adjustment for potential confounders between adult twins, after exclusion of those twin pairs including at least one twin taking antihypertensive drugs, and by zygosity. RESULTS: Reported mean birth weights of heavier and lighter twins were 2.51 (SD 0.61) v 2.12 (0.59) kg respectively. A graded inverse relation between strata of within pair differences in birth weight and differences in adult blood pressure was apparent, with an adjusted blood pressure range of 8.7/5.1 mm Hg across the four strata (test for trend: systolic, P=0.05; diastolic, P=0.09). After excluding those women taking antihypertensive drugs the significance of the association was similar (systolic, P=0.04; diastolic, P=0.10). When differences in blood pressure were stratified for zygosity similar but non-significant trends were apparent. CONCLUSION: It would seem that birth weight is inversely associated with adult blood pressure and that this association is independent of parental confounding variables probably including, in view of the findings in monozygotic twins, genetic factors. The observed blood pressure differences are likely to result from retarded intrauterine growth due to placental dysfunction rather than inadequate maternal nutrition.

Adult↗
PubMed1999

Effect on stroke of different progestagens in low oestrogen dose oral contraceptives. WHO Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception.

The multicentre WHO collaborative case-control study had limited power to differentiate stroke risks by progestagen component in low dose combined oral contraceptives. Given this caveat, odds ratios for ischaemic, haemorrhagic, and all strokes combined associated with use of oral contraceptives containing desogestrel or gestodene ("third generation") were found to be similar to those containing levonorgestrel in this study.

Adult↗
PubMed1999

Migraine and stroke in young women: case-control study. The World Health Organisation Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception.

OBJECTIVE: To investigate the association between migraine and ischaemic or haemorrhagic stroke in young women. DESIGN: Hospital based case-control study. SETTING: Five European centres participating in the World Health Organisation Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception. SUBJECTS: 291 women aged 20-44 years with ischaemic, haemorrhagic, or unclassified arterial stroke compared with 736 age and hospital matched controls. INTERVENTION: Questionnaire. MAIN OUTCOME MEASURE: Self reported history of headaches. RESULTS: Adjusted odds ratios associated with a personal history of migraine were 1.78 (95% confidence intervals, 1.14 to 2.77), 3.54 (1.30 to 9.61), and 1.10 (0.63 to 1.94) for all stroke, ischaemic stroke, and haemorrhagic stroke respectively. Odds ratios for ischaemic stroke were similar for classical migraine (with aura) (3.81, 1.26 to 11.5) and simple migraine (without aura) (2.97, 0.66 to 13.5). A family history of migraine, irrespective of personal history, was also associated with increased odds ratios, not only for ischaemic stroke but also haemorrhagic stroke. In migrainous women, coexistent use of oral contraceptives or a history of high blood pressure or smoking had greater than multiplicative effects on the odds ratios for ischaemic stroke associated with migraine alone. Change in the frequency or type of migraine on using oral contraceptives did not predict subsequent stroke. Between 20% and 40% of strokes in women with migraine seemed to develop directly from a migraine attack. CONCLUSIONS: Migraine in women of childbearing age significantly increases the risk of ischaemic but not haemorrhagic stroke. The coexistence of oral contraceptive use, high blood pressure, or smoking seems to exert a greater than multiplicative effect on the risk of ischaemic stroke associated with migraine.

Adult↗
PubMed1999

Modified radical hysterectomy for early Ib cervical cancer.

A total of 39 patients with selected early Ib cervical cancer were treated with modified radical hysterectomy (MRH) and compared with 102 patients with nonbulky Ib cervical cancer treated with radical hysterectomy (RH). Postoperative voiding difficulty (15.4 vs 46%) and constipation (43.6 vs 74.5%) were significantly less after MRH than after RH. All patients with MRH were followed uneventfully and the 3-year survival rate is 100%. No recurrence or persistence of disease was noted. It is suggested that patients with exophytic squamous cell carcinoma of the cervix less than 2 cm in diameter and invading less than 10 mm, as diagnosed by conization, may be effectively treated with MRH, resulting in less morbidity.

Female↗
PubMed1999

Protein kinase C isoforms during the development of deciduomata in pregnant rats.

In this study, we determined the expression of protein kinase C (PKC) isoforms during pregnancy. At pregnant duration, PKC alpha was down-modulated in the deciduomata but not in the myometrium. Down-modulation was compatible with the increase in cell mitosis, which reached a maximum at 8-9 days. On the other hand, PKC zeta was not down-modulated. It was increased both in the cytosolic and particulate fractions of the deciduomata, and paralleled the frequency of decidual cell mitosis. The other PKC isoform of delta was also increased, but it was associated with the cell regression. Therefore, these findings confirmed that the variable expression of PKC isoforms in decidualizing tissue may be involved in the modulation of decidual cell growth.

Animals↗
PubMed1999

Ethnic differences in the identification of left ventricular hypertrophy in the hypertensive patient.

Left ventricular hypertrophy (LVH) is more prevalent in black than white hypertensives, but this difference is greater when identified by electrocardiography (ECG) than by echocardiography. We evaluated the proposal that current ECG criteria for LVH are less specific, and therefore, less useful, in blacks than whites. In a retrospective cross-sectional study, 408 subjects (271 white, 137 black) referred to a hypertension clinic for assessment of hypertension underwent measurement of blood pressure, ECG voltages (Sokolow-Lyon and Cornell sex-specific), and echocardiographic left ventricular mass index (LVMI). Black subjects had greater ECG voltages than whites, even when closely matched for LVMI. In black subjects, current ECG criteria were twice as sensitive as in whites (Sokolow-Lyon: 44.9% v 22.5%, P = .003. Cornell: 30.4% v 15.7%, P = .03). They were less specific in blacks using the Sokolow-Lyon criteria (73.5% v 86.8%, P = .02) but this failed to reach significance using the Cornell criteria (83.8% v 91.8%, P = .07). When voltage criteria were adjusted to give matched sensitivities and specificities, respectively, differences in specificity and sensitivity were no longer apparent. Receiver operating characteristic curve analyses confirmed no significant differences in overall performance of either ECG criteria between blacks and whites. In conclusion, ECG detection of LVH is insensitive in both ethnic groups. Sensitivity is higher in blacks due to higher LVMI in those with LVH. Apparent differences in specificity are due to ethnic differences in ECG voltages that are unrelated to differences in LVMI. When these differences are taken into account, there are no overall differences in test accuracy. However, given the prognostic importance of the detection of LVH, currently accepted ECG voltage criteria for the detection of LVH remain of equal or greater value in black hypertensives compared with whites.

Adult↗
PubMed1999

Effects of a nitric oxide scavenger, carboxy-PTIO, on isoflurane MAC and cerebellar nitric oxide synthase activity in rats.

Recent studies have indicated that nitric oxide may play a role in inhalation anaesthesia. Inhibition of nitric oxide synthase reduces the minimum alveolar concentration (MAC) for inhalation anaesthetics and decreases cerebellar nitric oxide synthase (NOS) activity in rats. In this study, we have explored further the role of nitric oxide in isoflurane anaesthesia by examining the effects of a nitric oxide scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO 0.075-0.6 mg kg-1) on MAC values and cerebellar NOS activity in rats. Bolus injection of carboxy-PTIO at doses greater than 0.15 mg kg-1 reduced the MAC value of isoflurane (mean 1.36 (SEM 0.07)% at 0.15 mg kg-1, 1.39 (0.14)% at 0.3 mg kg-1 and 1.31 (0.06)% at 0.6 mg kg-1 vs control value of 1.61 (0.19)%. Administration of carboxy-PTIO 0.125 and 0.15 mg kg-1 resulted in increased cerebellar NOS activity during isoflurane anaesthesia (P < 0.05). These findings suggest that the level of nitric oxide may set a baseline from which isoflurane then acts.

Anesthetics, Inhalation↗
PubMed1999

Respiratory abnormalities among male foundry workers in central Taiwan.

The objectives of this study were to determine the relationship between exposure levels and respiratory abnormalities, to measure FVC and FEV1(1) changes per year based on work duties and to investigate the prevalence of and factors related to pneumoconiosis. A total of 583 male workers from 50 iron foundries in central Taiwan were investigated. First, workers' respiratory symptoms were categorized using a modified American Thoracic Society (ATS) questionnaire and then were verified by physician's examination. Next, pulmonary function tests were performed including: forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced expiratory flow rate. A chest radiograph was used to diagnose pneumoconiosis according to ILO criteria. Furnace workers were found to have the highest prevalence of chronic phlegm, thoracic disorders and chronic bronchitis. In general, smokers had a higher prevalence of respiratory symptoms as compared with non-smokers. Pulmonary function abnormalities and pneumoconiosis were closely linked to smoking and work duration. After adjusting for age, height and smoking there was a significant decrease based on work duration in FVC and FEV1 for furnace and moulding workers compared with after-processing and administrative workers. The overall prevalence of pneumoconiosis was 8.8%, highest among furnace (16.3%) and after-processing workers (11.4%) and lowest among administrative workers (2.5%). Using multiple logistic regression, the risk of developing pneumoconiosis (as compared with the administrative workers) for furnace workers was highest (8.98 times greater risk), followed by after-processing workers (6.77 times greater risk) and moulding workers (5.41 times greater risk). Prolonged exposure to free silica, and smoking habits, can result in respiratory abnormalities among foundry workers.

Adult↗
PubMed1999

Rahnella aquatilis sepsis in an immunocompetent adult.

Rahnella aquatilis, a rare enteric gram-negative rod which is infrequently isolated in immunocompromised patients, was isolated as a causative organism of sepsis in a 26-year-old immunocompetent male patient. The contaminated intravenous fluid was confirmed to be the source of the organism.

Adult↗
PubMed1998

Prevalence of and factors related to pneumoconiosis among foundry workers in central Taiwan.

The objective of this study was to investigate the prevalence of and factors related to pneumoconiosis in foundry workers. Seven hundred and eighteen workers from 50 foundries in central Taiwan were interviewed using a constructed questionnaire. A full-sized PA chest radiograph was used to diagnose pneumoconiosis, according to ILO criteria. Overall, pneumoconiosis was found in 7.5% of the workers. The highest prevalence was found among furnace workers (15.9%) and molding workers (8.40%). All foundry workers except those in administrative positions had a significantly increased risk of developing pneumoconiosis. Using a multiple logistic regression, compared to administrative workers, furnace workers had the highest risk (10.63 times), followed by post-treatment workers (6.63 times), and molding workers (5.41 times). In conclusion, the prevalence of pneumoconiosis was significantly related to high concentrations of dust, especially with a high proportion of free silica, however, smoking and length of exposure were also contributing factors.

Adult↗
PubMed1998

Absence of PTEN/MMAC1 germ-line mutations in sporadic Bannayan-Riley-Ruvalcaba syndrome.

Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a rare hamartomatous polyposis condition with features of macrocephaly, intestinal juvenile polyposis, developmental delay, lipomas, and pigmentation spots of the male genitalia. An autosomal dominant pattern of inheritance exists in some families, but others appear as sporadic cases. Germ-line mutations in PTEN, a tyrosine phosphatase and putative tumor suppressor gene, have been demonstrated in two families with BRRS, and chromatin loss at the PTEN gene locus on chromosome 10q23 has been demonstrated in two BRRS patients. Germ-line mutations in PTEN have also been described in Cowden disease and in a small number of patients with juvenile polyposis syndrome. In an attempt to assess the nature of PTEN mutations in BRRS, we analyzed three sporadic BRRS patients for chromosome 10q23 deletion or PTEN germ-line mutations. All 3 patients demonstrated no loss of parental alleles at 15 chromosome 10q23 markers that encompassed the region of PTEN. In addition, analysis of mRNA and genomic DNA revealed no nonsense, missense, or insertion/deletion mutations of PTEN. Thus, other mechanisms besides mutation of PTEN must have occurred to cause BRRS in these patients. We speculate that BRRS and juvenile polyposis syndrome may have a heterogeneous etiology to cause their syndromes.

DNA↗
PubMed1998

Effects of nicotine on spontaneous and amphetamine-induced motor behaviors: the differences between nicotine tolerant and nontolerant rats.

This study was designed to investigate the effect of nicotine on spontaneous and amphetamine (AMP)-induced motor activity in rats with or without tolerance to nicotine. Tolerance were induced by treating the rats with nicotine (0.3 mg/kg, s.c.) 2 hr before receiving challenge doses. Motor activity including locomotion and stereotypy was monitored automatically by videocamera every 15 min for 90 min. The results indicated that: (1) Nicotine increased spontaneous locomotion at 0.15 or 0.3 mg/kg (s.c.) in naive rats and at 0.6 mg/kg in tolerant rats. Nicotine also slightly affected AMP-induced locomotion at 0.15, 0.3 or 0.6 mg/kg in both naive and tolerant rats, and (2) Nicotine increased spontaneous stereotypy at 0.3 or 0.6 mg/kg in naive rats only and showed no effect on AMP-induced stereotypy in either naive or tolerant rats. Comparing the results of spontaneous motor activity between naive and tolerant rats, it revealed behavioral desensitization in locomotion at low doses (0.15 or 0.3 mg/kg) and hyperlocomotion at higher dose (0.6 mg/kg), and revealed desensitization in stereotypy at 0.3 or 0.6 mg/kg. Moreover, nicotine had temporary (at 0-15 min interval) attenuating effect on AMP-induced locomotion in naive rats but showed a potentiating effect on AMP-induced locomotion in tolerant rats. The present results indicated that acute tolerance modified the action of nicotine in both spontaneous and AMP-induced locomotion, while stereotypy was changed only in the spontaneous one but not in the AMP-induced one. In other words, acute tolerance modified the effect of nicotine on locomotion-related dopaminergic system, and it affected the stereotypy-related dopaminergic system only in the spontaneous one but not in the AMP-induced one.

Adenosine Monophosphate↗
PubMed1998

Protein kinase C isoforms during the development of deciduomata in pseudopregnant rats.

In this study, we determined the expression of protein kinase C (PKC) isoforms during trauma-induced decidualization. The findings revealed that at least five PKC isoforms (alpha, delta, zeta, iota and lambda) were present in both control and decidualized tissues. After trauma-stimulation, PKC alpha was down-modulated in the deciduomata but not in the myometrium. Down-modulation was compatible with the increase in cell mitosis which reached a maximum at 2-3 days. On the other hand, PKC zeta was not down-modulated. It was increased both in the deciduomata and myometrium, and paralleled the frequency of decidual cell mitosis. The PKC isoforms of delta, iota and lambda were also increased, but they were associated with the depression of cell mitosis. Therefore, these findings suggested that the variable expression of PKC isoforms in trauma-induced decidualizing tissue in pseudopregnant rats may be involved in the modulation of decidual cell growth.

Animals↗