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Biomedical subjects

C J Chang

Publications and source records attributed to C J Chang.

At least 109 records · Page 6Linked to original sources
PubMed1998

Characterization of the hrpC and hrpRS operons of Pseudomonas syringae pathovars syringae, tomato, and glycinea and analysis of the ability of hrpF, hrpG, hrcC, hrpT, and hrpV mutants to elicit the hypersensitive response and disease in plants.

The species Pseudomonas syringae encompasses plant pathogens with differing host specificities and corresponding pathovar designations. P. syringae requires the Hrp (type III protein secretion) system, encoded by a 25-kb cluster of hrp and hrc genes, in order to elicit the hypersensitive response (HR) in nonhosts or to be pathogenic in hosts. DNA sequence analysis of the hrpC and hrpRS operons of P. syringae pv. syringae 61 (brown spot of beans), P. syringae pv. glycinea U1 (bacterial blight of soybeans), and P. syringae pv. tomato DC3000 (bacterial speck of tomatos) revealed that the 13 genes comprising the right half of the hrp cluster (including those in the previously sequenced hrpZ operon) are conserved and identically arranged. The hrpC operon is comprised of hrpF, hrpG, hrcC, hrpT, and hrpV. hrcC encodes a putative outer membrane protein that is conserved in all type III secretion systems. The other four genes appear to be characteristic of group I Hrp systems, such as those possessed by P. syringae and Erwinia amylovora. The predicted products of these four genes in P. syringae pv. syringae 61 are HrpF (8 kDa), HrpG (15.4 kDa), HrpT (7.5 kDa), and HrpV (13.4 kDa). HrpT is a putative outer membrane lipoprotein. HrpF, HrpG, and HrpV are all hydrophilic proteins lacking N-terminal signal peptides. The HrpG, HrcC, HrpT, and HrpV proteins of P. syringae pathovars syringae and tomato (the two most divergent pathovars) had at least 76% amino acid identity with each other, whereas the HrpF proteins of these two pathovars had only 36% amino acid identity. The HrpF proteins of P. syringae pathovars syringae and glycinea also showed significant similarity to the HrpA pilin protein of P. syringae pathovar tomato. Functionally nonpolar mutations were introduced into each of the genes in the hrpC operon of P. syringae pv. syringae 61 by insertion of an nptII cartridge lacking a transcription terminator. The mutants were assayed for their ability to elicit the HR in nonhost tobacco leaves or to multiply and cause disease in host bean leaves. Mutations in hrpF, hrcC, and hrpT abolished or greatly reduced the ability of P. syringae pv. syringae 61 to elicit the HR in tobacco. The hrpG mutant had only weakly reduced HR activity, and the activity of the hrpV mutant was indistinguishable from that of the wild type. Each of the mutations could be complemented, but surprisingly, the hrpV subclone caused a reduction in the HR elicitation ability of the DeltahrpV::nptII mutant. The hrpF and hrcC mutants caused no disease in beans, whereas the hrpG, hrpT, and hrpV mutants had reduced virulence. Similarly, the hrcC mutant grew little in beans, whereas the other mutants grew to intermediate levels in comparison with the wild type. These results indicate that HrpC and HrpF have essential functions in the Hrp system, that HrpG and HrpT contribute quantitatively but are not essential, and that HrpV is a candidate negative regulator of the Hrp system.

Amino Acid Sequence↗
PubMed1998

Coactivator TIF1beta interacts with transcription factor C/EBPbeta and glucocorticoid receptor to induce alpha1-acid glycoprotein gene expression.

The transcription of the alpha1-acid glycoprotein gene is induced by inflammatory cytokines and glucocorticoids. C/EBPbeta is a major transcription factor involved in the induction of the agp gene by some cytokines. In this report, we have identified a novel transcriptional intermediary factor, TIF1beta, which could enhance the transcription of the agp gene by the glucocorticoid receptor (GR) and C/EBPbeta. TIF1beta belongs to a subgroup of RING (really interesting new gene) finger proteins that contain a RING finger preceding two B box-type fingers and a putative coiled-coil domain (RBCC domain). Immunoprecipitation experiments showed that the interaction between GR and TIF1beta is ligand independent. The overexpression of the TIF1beta gene enhances GR-regulated expression in a ligand- and glucocorticoid-responsive element (GRE)-dependent manner. TIF1beta can also augment C/EBPbeta-mediated activity on wild-type and GRE-mutated agp genes, but this augmentation is diminished when all three C/EBPbeta-binding elements are mutated. Functional and biochemical characterizations indicated that the bZIP domain of C/EBPbeta and the RBCC domain, plant homeodomain finger, and bromodomain of TIF1beta are crucial for the interactions of these proteins. Taken together, these results suggest that TIF1beta serves as a converging mediator of signal transduction pathways of glucocorticoids and some inflammatory cytokines.

Animals↗
PubMed1998

Human immunodeficiency virus-associated nephropathy in the Bronx: low prevalence in a predominantly Hispanic population.

Reports of human immunodeficiency virus-associated nephropathy (HIVAN) occurring in Hispanics, females and heterosexuals are scarce. We reviewed 858 charts from our total HIV population to determine the prevalence and epidemiology of HIVAN at our center, and to evaluate the renal and patient survival among individual groups, according to race, sex and HIV risk factor. The prevalence of HIVAN was low (1.9%), relative to other centers (4-13%). Although Hispanics accounted for 56% of the HIV population, only 38% of HIVAN patients were Hispanic. The absolute risk of HIVAN in blacks was 3. 6%, and in Hispanics was 1.3%. The relative risk of blacks vs. Hispanics was 2.8% (p < 0.04). Women and men were represented equally in both the HIVAN and HIV populations. The mean (+/- SE) rate of decline in glomerular filtration rate was 3.7 +/- 0.9 ml/min/month, and patient survival following the onset of HIVAN was 23.6 +/- 4.8 months. We found no difference in renal or patient survival between individual groups. In summary, the risk of HIVAN in Hispanics is similar to that for whites. Male sex is not an independent risk factor. Both renal and patient survival are similar in blacks and Hispanics, and in men compared to women.

AIDS-Associated Nephropathy↗
PubMed1998

Sustained attention deficit and schizotypal personality features in nonpsychotic relatives of schizophrenic patients.

OBJECTIVE: The authors investigated whether nonpsychotic relatives of schizophrenic probands have an elevated risk of deficits in sustained attention as measured by the Continuous Performance Test (CPT), whether such deficits are associated with specific factors of schizotypy, and whether poor CPT performance by probands predicts poor performance by their relatives. In addition, the heritability of CPT performance in the families of schizophrenic probands was estimated. METHOD: The study subjects were 60 schizophrenic probands, 148 of their first-degree relatives, 20 normal comparison probands, and 42 of the comparison probands' first-degree relatives. Subjects completed undegraded and 25% degraded sessions of the CPT and were interviewed with use of the Chinese version of the Diagnostic Interview for Genetic Studies. Subjects' CPT sensitivity indexes, d', were standardized against those of a community sample of 345 subjects, with adjustment for age, sex, and level of education. RESULTS: On average, the d' values of the relatives of schizophrenic probands were lower than those of the relatives of comparison probands but higher than those of schizophrenic probands. Lower sensitivity indexes among the relatives of schizophrenic patients were associated with the interpersonal dysfunction and disorganization factors of schizotypy but not the cognitive/perceptual factor. When schizophrenic probands were divided into two subgroups by a cutoff of -3.0 for adjusted z score on the CPT, the d' values of relatives of probands with CPT deficits were lower than those of relatives of probands without deficits. The estimated heritability of performance on the CPT ranged from 0.48 to 0.62. CONCLUSIONS: Sustained attention deficit may be a genetic vulnerability marker for schizophrenia, and it may be more useful in linkage analysis than traditional phenotype definitions of schizophrenia.

Adult↗
PubMed1998

Fasting plasma glucose in screening for diabetes in the Taiwanese population.

OBJECTIVE: To reveal the relationship between fasting and 2-h postload plasma glucose and to examine the appropriate fasting glucose cutoff as the primary screening test for diabetes. RESEARCH DESIGN AND METHODS: We recruited 5,303 subjects from preventive services of the National Cheng Kung University Hospital. Exclusion criteria were age <20 years, pregnancy, known diabetes, and a history of recent surgery, trauma, or illness. All subjects received the 75-g oral glucose tolerance test. The relationship between fasting and 2-h glucose was examined. Sensitivities, specificities, efficiency, and predictive values were assessed at different cutoffs of fasting glucose for prediction of diabetes. RESULTS: The best fit model for the relationship between fasting and 2-h glucose was fasting glucose = 4.914-0.060 x (2-h glucose) + 0.0144 x (2-h glucose)2. From this model, the fasting glucose was 6.0 mmol/l when 2-h glucose was 11.1 mmol/l. A fasting glucose with 6.25 mmol/l gave the same diabetes prevalence as the World Health Organization 2-h glucose criterion. When 7.8 mmol/l was the fasting glucose cutoff, the sensitivity was 28.5%. Lowering the cutoff from 7.8 to 7.0 mmol/l increased the sensitivity by 11.2% and slightly reduced the specificity and positive predictive value. If the cutoffs were 6.25 and 6.0 mmol/l, the sensitivity increased and the specificity and the positive predictive value decreased accordingly. CONCLUSIONS: Our results suggest that fasting glucose as a screening criterion for diabetes could be revised downward to 7.0 mmol/l, because the slight reduction of positive predictive value was more than balanced by an apparent increase of sensitivity and insignificant change of specificity.

Adult↗
PubMed1998

Electron microscopic studies of microvasculature and sympathetic nerve fibers in dilated cardiomyopathy.

OBJECTIVE: To investigate the ultrastructural pathological alterations of the microvasculature and nerve fibers in the endomyocardial biopsied specimens of the left ventricular myocardium obtained from patients with idiopathic dilated cardiomyopathy and chronic heart failure. METHODS: Transmission electron microscopic observations of endomyocardial biopsied specimens of the left ventricular myocardium were carried out in 10 patients with idiopathic dilated cardiomyopathy and chronic heart failure. RESULTS: Various degrees of ultrastructural pathological alterations in the microvessels and sympathetic nerves in the diseased myocardium were consistently demonstrated in idiopathic dilated cardiomyopathy. In addition, abnormal accumulation of collagen tissue and edematous fluid were often seen in the interspace between myocardial cells and nerve endings and capillaries. CONCLUSIONS: Based on the ultrastructural pathological findings in this study, we consider that all the structures forming the muscle cells and the tissues around them, namely the microvessels and nerves may participate in the pathological process in the course of dilated cardiomyopathy. The damage of microvasculature and sympathetic nerves resulting from the underlying disease processes are considered to be an important pathogenetic mechanism responsible for progressive development of myocardial degeneration and dysfunction throughout the course of the disease. It is hoped that our data may provide some insights into the understanding of the role of microcirculation and sympathetic nerves in the etiopathogenesis of dilated cardiomyopathy.

Adult↗
PubMed1998

Osteochondritis dissecans of the talar dome in a collegiate swimmer: a case report.

OBJECTIVE: To present the case of an intercollegiate swimmer with a stage IV lateral talar dome injury and associated bony fragments. BACKGROUND: Lack of distinct diagnostic symptoms, low index of clinical suspicion, and the difficulty of visualizing the early stages of this injury on standard x-rays cause frequent misdiagnosis of talar dome lesions. DIFFERENTIAL DIAGNOSIS: Ganglion cyst, with inflammatory synovitis secondary to rupture of cyst; loose bodies from previous occult fracture; osteochondral fracture. TREATMENT: Initial treatment with nonsteroidal antiinflammatory drugs and a posterior splint for comfort, followed by arthroscopic excision of loose bodies with abrasion and drilling arthroplasty. UNIQUENESS: Patient presented to the team physician for care of acute left medial ankle pain after the athletic trainer had attempted to rupture a ganglion cyst on the anterolateral aspect of the patient's ankle. CONCLUSIONS: Increased clinical suspicion is necessary to correctly diagnose osteochondral lesions, particularly in the early stages. Aggressive treatment of talar dome lesions has a good success rate and may be an attractive option for competitive athletes.

Journal Article↗
PubMed1998

Photodynamic therapy for facial squamous cell carcinoma in cats using Photofrin.

BACKGROUND: Photodynamic therapy (PDT) has been shown to be an effective treatment modality for surface-oriented neoplasms of the skin, respiratory, gastrointestinal, and urogenital systems. The purpose of our study was to assess the safety and efficacy of PDT using Photofrin in the treatment of squamous cell carcinomas of feline facial skin. MATERIALS AND METHODS: Cats with naturally occurring squamous cell carcinomas of the skin were entered into the study. PDT was delivered to the tumors using an argon-pumped dye laser 48 hours after the administration of the photosensitizer porfimer sodium (Photofrin). Following treatment, the tumors were evaluated for complete response rates and local control durations. RESULTS: Eight tumors were staged T1a, 9 staged T1b, and 14 staged T2b. Complete response rates as well as local control durations were significantly related to stage (p < 0.0001). Complete response was achieved in 100% of the T1a tumors and 53% of the T1b tumors; the overall 1-year local control rate for all treated tumors was 62%. Clinical, hematological, and biochemical evidence of toxicity was not seen in any cat following drug administration. CONCLUSION: PDT with the photosensitizer Photofrin was safe and effective in treating early stage squamous cell carcinomas of the feline skin.

Animals↗
PubMed1998

Temporal trends in the progression of human immunodeficiency virus disease in a cohort of drug users.

We evaluated changes over time in rates of progression to AIDS, mortality, and distribution of AIDS-defining illnesses in 524 human immunodeficiency virus (HIV)-seropositive injection drug users enrolled between 1986 and 1995 in a prospective study of HIV infection in the Bronx, NY. At enrollment, participants attended a hospital-affiliated methadone maintenance program with on-site primary care. Using the 1993 clinical definition of AIDS, we found that the hazard ratio (HR) of progression to AIDS declined for enrollees over time in comparison with the referent group of persons enrolled in 1986-1987. For program enrollees in 1988-1989, the HR was 1.0 [95% confidence interval (CI) = 0.6-1.6]; for enrollees in 1990-1991, the HR was 0.3 (95% CI = 0.1-0.9); for enrollees in 1992-1993, the HR was 0.5 (95% CI = 0.3-0.9); and for enrollees in 1994-1995, the HR was 0.2 (95% CI = 0.1-0.7), after controlling on initial CD4+ cell counts and age. Nevertheless, the greater AIDS-free time of later study entrants was not associated with reduced mortality. The study provides evidence that drug users with access to primary care likely benefited from improved management of HIV disease in prolonging AIDS-free time but, through 1996, did not experience greater survival.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Health and satisfaction among the elderly with chronic conditions: demographic differentials.

This study examines the state of health (physical and mental health) and avowed satisfaction (toward hospital services and towards life-as-a-whole), among 172 elderly subjects (108 outpatients from a family medicine clinic and 64 community residents) with chronic conditions living in Kaohsiung city. Results indicated that (a) the elderly did not perceive any great impact of illness(es) upon their lives and both their physical and mental health were satisfactory; (b) the elderly were generally satisfied with both the hospital services and life as a whole; (c) there were meaningful group differentials in health and satisfaction: older, male, single and financially-dependent elderly had poorer physical and mental health; female, single and financially dependent elderly avowed lower life satisfaction.

Aged↗
PubMed1998

Seroepidemiology of hepatitis C virus infection among drug abusers in southern Taiwan.

The purpose of this study was to determine the risk factors for hepatitis C virus (HCV) infection among drug abusers in southern Taiwan. This survey included 935 drug abusers from Kaohsiung Narcotic Abstention Institute and Kaohsiung prison. The prevalence of anti-HCV antibody was 29.1% among male drug abusers and 19.4% among female drug abusers. The seroprevalence of anti-HCV antibody was 66.4% among intravenous drug abusers and 14.4% among nonintravenous drug abusers. Intravenous drug use, a history of hepatitis, having tattoos, and age were independently related to HCV seropositivity among drug abusers. The prevalence of anti-HCV antibody concentrations significantly increased (10.8-fold) with intravenous drug abuse and with having tattoos (1.7-fold). These findings suggest that hepatitis C virus is mainly transmitted by the parenteral route among drug abusers in southern Taiwan. Due to the high rate of HCV infection among drug abusers, investigation of high-risk behavior should be routine in this group. To prevent HCV infection, emphasis on the use of sterile needles and aseptic procedures in tattooing is important in Taiwan.

Adolescent↗
PubMed1997

Structure-activity relationships of diverse Annonaceous acetogenins against multidrug resistant human mammary adenocarcinoma (MCF-7/Adr) cells.

Fourteen structurally diverse Annonaceous acetogenins, representing the three main classes of bis-adjacent, bis-nonadjacent, and single-THF ring(s), were tested for their ability to inhibit the growth of adriamycin resistant human mammary adenocarcinoma (MCF-7/Adr) cells. This cell line is resistant to treatment with adriamycin, vincristine, and vinblastine and is, thus, multidrug resistant (MDR). Among a series of bis-adjacent THF ring acetogenins, those with the stereochemistry of threo-trans-threo-trans-erythro (from C-15 to C-24) were the most potent with as much as 250 times the potency of adriamycin. A spacing of 13 carbons between the flanking hydroxyl of the THF ring system and the gamma-unsaturated lactone seems to be optimum with a spacing of 11 and 9 carbons being significantly less active. Several single-THF ring compounds were also quite potent with gigantetrocin A (11) being the most potent compound tested. The acetogenins may, thus, have chemotherapeutic potential, especially with regard to MDR tumors.

Adenocarcinoma↗
PubMed1997

Concordance of positive and negative symptoms in coaffected sib-pairs with schizophrenia.

Positive and negative symptom (NGS) dimensions were examined for their concordance in 46 coaffected schizophrenic sib-pairs. Results showed that the symptom dimensions of negative symptoms (NGS), delusion-hallucination (DHS), and thought disorganization (TDS) could be formulated. Discrete genetic endowment of these three symptom dimensions was not found as shown by the low concordance in sib pair analysis (kappa = 0.20-0.30). Thirty-seven pairs (80.4%) and 21 pairs (45.7%) had liability, defined by the presence of NGS in any one member of the coaffected sib-pairs, of NGS of "any degree", and of "severe degree" in 46 sib-pairs, respectively. Both groups had high prevalence (59.1-81.0%) of positive symptoms. Another 9 (19.6%) and 25 (54.3%) pairs had no liability of NGS of "any degree" or of "severe degree" out of 46 sib-pairs, respectively. These two groups had high concordance (kappa = 0.45-1.00) of TDS or DHS between coaffected sib-pairs. Based on the results, it is hypothesized that schizophrenia, as defined by DSM-III-R, may consist of two subtypes: one has liability of NGS and a high prevalence of positive symptoms, while the other has only positive symptoms.

Delusions↗
PubMed1997

Unscheduled DNA replication precedes apoptosis of photoreceptors expressing SV40 T antigen.

Expression of simian virus 40 T antigen (Tag) in the rod photoreceptors of transgenic mice leads to cell death that is completed by the end of the third week of postnatal development. To understand the mechanistic link between Tag expression and the death of the expressing photoreceptors, cell cycle activity was followed in a transgenic mouse family that expresses Tag directed by the mouse opsin promoter. Tag-expressing photoreceptors also expressed rhodopsin suggesting that these cells were differentiated. The presence of Tag in the photoreceptors induced the expression of both proliferating cell nuclear antigen (PCNA) and thymidine kinase (TK). The abnormally high levels of PCNA and TK continued until the complete disappearance of the cells expressing Tag. Photoreceptor cell death was also associated with continued DNA synthesis that ceased shortly after postnatal day 16. The specific loss of the rod photoreceptors that re-entered the cell cycle accounted entirely for the loss of photoreceptors from the outer nuclear layer. The antiproliferative nature of the mature retina is directly involved in the apoptotic death of photoreceptors expressing Tag.

Animals↗
PubMed1997

Effects of beta-carotene and other factors on outcome of cervical dysplasia and human papillomavirus infection.

Women with histopathologically confirmed cervical intraepithelial neoplasia (CIN) were followed at 3-month intervals in a randomized double-blinded trial to evaluate the efficacy of beta-carotene to cause regression of CIN. Questionnaire data, plasma levels of micronutrients, and a cervicovaginal lavage for human papillomavirus (HPV) detection were obtained at each visit, and an endpoint biopsy was performed at 9 months. Sixty-nine subjects had a biopsy endpoint evaluation; 9 of 39 (23%) subjects in the beta-carotene group versus 14 of 30 (47%) in the placebo group had regression of CIN (P = 0.039). Independent risk factors for persistent CIN at 9 months included type-specific persistent HPV infection (OR = 11.38, P = 0.006) and continual HPV infection with a high viral load (OR = 14.25, P = 0.007) at baseline and 9 months, an initial diagnosis of > or =CIN II (OR = 6.74, P = 0.016), and older age (OR for > or =25 years = 4.10, P = 0.072). After controlling for these factors, the beta-carotene and placebo groups did not differ in risk for having CIN at 9 months (OR = 1.53, P = 0.550). Resolution of baseline HPV infection was significantly correlated with non-high-risk HPV types (RR = 2.94, P = 0.015), age <25 years (RR = 2.62, P = 0.014), and douching after sexual intercourse (RR = 3.02, P = 0.012), but not with randomization group. Our data indicate that a large proportion of mild CIN lesions regress; age and HPV infection play an important role in the natural course of CIN; and repeated HPV testing may have a value in distinguishing women who need aggressive treatment for CIN versus those who do not. Supplementation of beta-carotene does not appear to have a detectable benefit in treatment of CIN.

Adult↗
PubMed1997

Contrasting effects of identical nutrients given parenterally or enterally after 70% hepatectomy: bacterial translocation.

High mortality occurs in rats with 70% hepatectomy fed intravenous (IV) total parenteral nutrition (TPN; 13.9% glucose, 4.17% amino acids, 1.46% fat, electrolytes, trace minerals, and vitamins providing 216 kcal.kg-1.d-1) but not when the identical nutrients are given at the same rate enterally (gastrostomy). We hypothesized that a difference in bacterial translocation (BT) was a contributing factor to this phenomenon. Forty-five male Sprague-Dawley rats (300-360 g) were divided into five groups and underwent the following: control (no operation), sham (intraperitoneal [IP] pentobarbital anesthesia, central venous and gastrostomy catheters, laparotomy, sham hepatectomy), standard oral feeding (SOF), TPN (IV nutrients), and total enteral nutrition (TEN; gastrostomy). The SOF, TPN, and TEN groups had IP pentobarbital anesthesia, central venous and gastrostomy catheters, and 70% hepatectomy. Postoperatively, control and SOF (both catheters plugged) rats ate a commercial rat chow and drank tap water ad libitum pre- and postoperatively. The sham, TPN, and TEN groups were given the identical infusate composition as above, but the nutrient concentrations were cut in half (110 kcal/kg) and three-quarters (165 kcal/kg) on postoperative days 1 and 2, respectively. At the end of postoperative day 2, all rats were euthanized. BT to mesenteric lymph nodes (MLNs), liver, spleen, and lungs was significantly higher in the TPN rats compared with all other groups, except that BT to the MLNs was similar in the TPN and TEN groups. Bacteremia was found only in the TPN rats. BT in TPN rats with 70% hepatectomy was significantly greater 48 h after operation than in those fed the identical nutrients enterally at the same rate; this correlates with the previously reported significantly greater mortality in rats with 70% hepatectomy receiving TPN.

Animals↗