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Biomedical subjects

J C Chang

Publications and source records attributed to J C Chang.

At least 91 records · Page 5Linked to original sources
PubMed1996

Relationship of uterine perfusion to outcome of intrauterine insemination.

This prospective study was undertaken to evaluate the prognostic value of uterine perfusion on the day of human chorionic gonadotropin administration in patients who were undergoing intrauterine insemination. Uterine perfusion was evaluated by measuring the pulsatility index of the ascending branch of the uterine arteries on the day of administration of human chorionic gonadotropin. No pregnancy occurred when the pulsatility index of the ascending branch of the uterine arteries was more than 3. The fecundity rate was 18% when the pulsatility index was less than 2 and was 19.8% when the pulsatility index was between 2 and 3 (not significant). The continuing pregnancy rate was 18% when the pulsatility index was less than 2, compared with 12.1% when the pulsatility index was between 2 and 3 (P < 0.05). Our data suggest that the measurement of uterine perfusion on the day of human chorionic gonadotropin administration may have predictive value regarding fecundity and the continuation of pregnancy in intrauterine insemination.

Adult↗
PubMed1996

Early discontinuation of gonadotropin-releasing hormone agonist in controlled ovarian hyperstimulation: a preliminary report.

The purpose of this study was to evaluate the applicability of continuing daily injectable GnRHa, after pituitary desensitization, for the first 4 or 5 days of ovarian stimulation. We proposed a new calculation and estimated that it took as early as 6 to 7 days for pituitary and gonadotropin release to return after cessation of daily administered leuprolide acetate. A modified regimen based on this new calculation, i.e. Daily administered GnRHa continued for the first 4 or 5 days with ovarian stimulation after pituitary desensitization had been achieved was applied to patients undergoing assisted reproductive technology (ART). Thirty-five patients prospectively assigned to use this early discontinuation regimen were analyzed with respect to age, indications, duration of ovarian stimulation, dose of exogenous gonadotropin required, ovarian response and oocytes obtained, rate of fertilization, and rates of pregnancy. There was no spontaneous LH surge occurred. Premature luteinization occurred in one patient. We concluded that, after pituitary desensitization, there was no spontaneous LH surge when daily administered GnRHa continued for 4 or 5 days only with ovarian stimulation. Impacts on the ART outcome required further evaluation in a prospectively randomized study. Based on theoretical estimation, cessation of GnRHa at the beginning of ovarian stimulation might eliminate most, but not all, spontaneous LH surges.

Adult↗
PubMed1996

Coamplification of the ZFX and ZFY genes for sex identification in preimplantation embryos.

Knowledge of the sex of an embryo may be particularly useful for couples who have a high risk of producing offspring with inherited genetic disorders. We present a rapid and reliable nested polymerase chain reaction strategy to simultaneously amplify the ZFX and ZFY genes at the single cell level. Forty single blastomeres isolated from six triploid preembryos were subjected to coamplification of ZFX and ZFY genes. The results obtained from the preembryo were consistent with the assigned genotype. The amplification rate was 80% for ZFX and 84% for ZFY. Our strategy can be applied to preimplantation diagnosis of single gene disorders, and is especially useful for preimplantation diagnosis and prevention of X-linked diseases in in vitro fertilization programs.

Blastocyst↗
PubMed1996

Multivariate analyses of the relationship between umbilical cord length and obstetric outcome.

To investigate the clinical significance of umbilical cord length in human pregnancies, 1087 deliveries at Kaohsiung Chang Gung Memorial Hospital from May 1995 to August 1995 were studied. Our data showed that male fetuses had longer cord length than female and vertex presentation had longer cord length than breech presentation. The cord length and placental weight were significantly related to the birth weight. We found that: 1) only intrauterine growth retardation was associated with the increased risk of fetal distress; 2) secondary arrest of labor and advanced gestational age were correlated with meconium stain; and 3) birth weight and presence of meconium stain were correlated with the secondary arrest (p < 0.05). However, there was no significant correlation between umbilical cord length and fetal well-being. As a result of multivariate analyses, we conclude that the umbilical cord length does not significantly correlate with either maternal age, gestational age (> or = 28 weeks), parity fetal outcome or intrauterine fetal well-being. Birth weight is the only characteristic that is correlated with cord length.

Adult↗
PubMed1996

Second trimester diagnosis of thanatophoric dysplasia.

Thanatophoric dysplasia is one of the most common skeletal dysplasia, with an incidence from 1:6,400 to 1:100,000 births. While the etiology is unknown, either autosomal recessive or polygenic transmission with 0.2% recurrence risk had been suggested. It is a lethal disorder characterized by extremely short ribs, tubular bones and macrocephaly. Death is often secondary to pulmonary hypoplasia caused by the small thoracic cavity. We present a fetus with shortening of four limbs, typical thanatophoric dwarfism, diagnosed by sonography at the 25th week of gestation. The second trimester diagnosis by ultrasound was crucial, because it gave an alternative option of pregnancy termination when the affected fetus was discovered.

Adult↗
PubMed1995

CD8+ T-cells in psoriatic lesions preferentially use T-cell receptors V beta 3 and/or V beta 13.1 genes.

Restricted T-cell receptor V beta gene use in animal models of autoimmune disease has led to the development of strategies to treat autoimmune disease by targeting the T-cell receptors of the pathogenic T-cells. Restricted T-cell receptor gene use has been noted in human autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. We report here the finding of restricted T-cell receptor gene use in psoriasis vulgaris, as well. Our results show an elevated skin (over PBL) expression of V beta 3 and/or V beta 13.1 messages in the CD8+ T-cells in a majority of patients studied. CDR3 sequence analysis on these two V beta s from the skin demonstrated monoclonality or marked oligoclonality. A second biopsy performed 3.5 to 8 months later in four patients, at the same or different lesions, again revealed an elevated V beta 3 and/or V beta 13.1 expression and clonality. Moreover, in three of the four patients, the same TcR V beta CDR3 rearrangement was found in both biopsies, although there was no V beta CDR3 homology noted between patients. In two patients in which V beta 3 and/or V beta 13.1 was not elevated in the CD8+ T-cell population, an increase in V beta 17 gene use and clonality was found. The persistence of V beta 3- and/or V beta 13.1-bearing CD8+ T-cells in lesions that did not undergo resolution suggests their role as effector cells rather than as regulatory cells. The effector function of these CD8+ T-cells is further supported by the clonality of TcR V beta sequence data, which indicates they are recruited and expanded in situ. The V beta s identified in this study are candidate targets for selective immunotherapeutic intervention in psoriasis.

Amino Acid Sequence↗
PubMed1995

The effect of passive smoking and tobacco exposure through breast milk on sudden infant death syndrome.

OBJECTIVE: To examine the relationship between sudden infant death syndrome (SIDS) and smoking during pregnancy; postnatal tobacco smoke exposure from the mother, father, live-in-adults, and day care providers; and postnatal smoke exposure from breast-feeding. DESIGN: Case-control study. SETTING: Five counties in Southern California. PARTICIPANTS: A total of 200 white, African-American, Hispanic, and Asian parents of infants who died of SIDS between 1989 and 1992 were compared with 200 control parents who delivered healthy infants. Case infants were matched to control infants on the basis of birth hospital, birth date, gender, and race. All information was obtained from a detailed telephone interview and validated with medical records. MAIN OUTCOME MEASURES: Risk of SIDS associated with passive smoking by the mother, father, live-in adults, and day care providers; smoking in the same room as the infant; total number of cigarettes smoked by all adults; and maternal smoking during the time period of breast-feeding. RESULTS: Conditional logistic regression resulted in overall adjusted odds ratios (ORs) for SIDS associated with passive smoke from the mother of 2.28, the father of 3.46, other live-in adults of 2.18, and all sources of 3.50 (95% confidence interval, 1.81 to 6.75), while simultaneously adjusting for birth weight, sleep position, prenatal care, medical conditions at birth, breast-feeding, and maternal smoking during pregnancy. A dose-response effect was noted for SIDS associated with increasing numbers of cigarettes, as well as total number of smokers. Breast-feeding was protective for SIDS among nonsmokers (OR = 0.37) but not smokers (OR = 1.38), when adjusting for potential confounders. CONCLUSIONS: Passive smoking in the same room as the infant increases the risk for SIDS. Physicians should educate new and prospective parents about the risk of tobacco smoke exposure during pregnancy and the first year of the infant's life.

Breast Feeding↗
PubMed1995

Lung cancer in nonsmoking women. Histology and survival patterns.

BACKGROUND: Despite the widespread view that important clinical and etiologic differences exist between histologic categories of lung cancer, few studies have examined the accuracy of hospital-reported pathologic diagnoses of lung cancer. METHODS: A review of pathologic material and an assessment of survival patterns were conducted in conjunction with a recently completed case-control study of lung cancer among nonsmoking women in Missouri. Using established protocols, tissue slides from tumors of 482 patients were reviewed by 3 pathologists. RESULTS: Adenocarcinoma was the most common histologic type among former smokers and lifetime nonsmokers. The overall agreement rate between the original and review diagnoses was 65.6%. The positive predictive value ranged from 0.33 for bronchioalveolar carcinomas to 0.84 for adenocarcinomas. Agreement rates for small, medium, and large hospitals were 63.1, 66.6, and 66.2%, respectively. Survival rates were highest for bronchioalveolar carcinoma and lowest for small cell carcinoma. CONCLUSION: Given the importance of lung cancer to public health and the need to examine risk by histologic type, these data indicate that pathologic review of registry-reported lung cancer cases may be an important component of large scale studies of etiology.

Adenocarcinoma↗
PubMed1995

Thymic epithelial neoplasms in transgenic mice expressing SV40 T antigen under the control of an erythroid-specific enhancer.

The beta-globin locus control region is known to be a powerful erythroid-specific enhancer. In an attempt to produce immortalized erythroid percursor cells, transgenic mice have been generated with the simian virus (SV) 40 T antigen gene under the control of the locus control region. As previously reported, transgenic mice did not develop erythroleukaemia, but rather succumbed to insulinomas and poorly differentiated rhabdomyosarcomas. This paper describes additional mice containing this transgene that developed thymomas of the mixed epithelial/lymphocytic type, in which only the epithelial component expressed the T antigen. Epithelial cell lines have been established from these tumours. This system may be useful in future studies on the pathogenesis of thymomas and the function of thymic epithelial cells.

Animals↗
PubMed1995

Insulin-secretory-granule specific T cell clones in human IDDM.

T cell clones reactive to beta-cell antigens prepared from different species were established in order to identify putative pathogenic T cells in human IDDM. We were able to generate T cell clones from patients, but not from controls, reactive specifically to the insulin secretory enriched fraction (ISG) of a rat insulinoma RIN cell line. This finding is suggestive of an in vivo priming by the antigen(s). To examine the relevance of these T cell clones in the pathogenesis of IDDM, we studied their cytokine profile. T cell clones from the newly onset patients had a Th1 cytokine profile, while those from the prediabetic patient were of the Th2 subtype. This segregation suggests that RIN-ISG contains antigen(s) involved in the pathogenesis of this disease, since IDDM is considered a cell-mediated or Th1 disease. Since two of these clones also responded to a hamster insulinoma cell line HIT, at least two antigens in RIN-ISG could be defined by this panel of T cell clones. Examination of CDR3 sequences confirmed the clonality of the dual-reactive T cell clones. The finding of HIT-reactive cells in IDDM patients may be useful in efforts to identify prediabetic patients for immune intervention. Dual reactivity may provide a better prognosis than single reactivity. In contrast to T cell clones reactive to insulinomas, T cell clones reactive to normal human ISG were not found after over 200 clones were screened. In addition, RIN-ISG specific clones did not respond to either normal human or rat ISG, suggesting that IDDM antigens are below detectable levels in normal beta cells.

Amino Acid Sequence↗
PubMed1995

Selenium content of Brazil nuts from two geographic locations in Brazil.

Brazil nuts (Bertholletia excelsa) natively contain very high concentrations of selenium. Since dietary selenium, including Brazil nuts, have been associated with protection against tumor development in laboratory animal studies, it was of interest to determine the selenium content of the nuts from different nut-growing regions of Brazil. In the work reported, 162 nuts from each of two regions (Acre-Rondonia and Manaus-Belem) were individually analyzed for selenium. The average +/- standard deviation and range of selenium concentrations in ppm, fresh weight for nuts from Acre-Rondonia and Manaus-Belem regions were, respectively, 3.06 +/- 4.01 (0.03-31.7) and 36.0 +/- 50.0 (1.25-512.0). The toxicology of Brazil nut consumption is discussed.

Brazil↗
PubMed1995

Reconstituted high-density lipoprotein neutralizes gram-negative bacterial lipopolysaccharides in human whole blood.

We have tested hypotheses relating lipoprotein structure to function as measured by the relative ability to neutralize endotoxin by comparing natural human lipoproteins, a chemically defined form of reconstituted high-density lipoprotein (R-HDL), and a lipid emulsion (Intralipid). The human whole-blood system was used as an in vitro model of lipopolysaccharide (LPS) binding protein and CD14-dependent activation of cytokine production. When lipoproteins were compared on the basis of protein content, R-HDL was most effective in reducing tumor necrosis factor alpha (TNF-alpha) production followed in order by very low density lipoprotein, low-density lipoprotein, Intralipid, and natural HDL. However, when these particles were compared by protein, phospholipid, cholesterol, or triglyceride content by stepwise linear regression analysis, only phospholipid was correlated to effectiveness (r2 = 0.873; P < 0.0001). Anti-CD14 monoclonal antibodies MY4 and 3C10 inhibited LPS binding protein and CD14-dependent activation of TNF-alpha production by LPS at LPS concentrations up to approximately 1.0 ng/ml. R-HDL (2 mg of protein per ml) blocked TNF-alpha production by LPS from both smooth- and rough-type gram-negative bacteria at concentrations up to 100 ng of LPS per ml but had little effect on heat-killed gram-positive Staphylococcus aureus and no effect on other LPS-independent stimuli tested. These results support our hypothesis that LPS is neutralized by binding to phospholipid on the surface of R-HDL and demonstrate that R-HDL is a potent inhibitor of the induction of TNF-alpha by LPS from both rough- and smooth-form gram-negative bacteria in whole human blood.

Antigens, CD↗
PubMed1995

Predictive value of endometrial sonography in ovulation induction for intrauterine insemination.

This prospective study was undertaken to evaluate the prognostic value of the endometrial sonographic pattern on the day of human chorionic gonadotropin (hCG) administration in patients who underwent intrauterine insemination. The endometrial sonographic patterns were classified as homogenous, hyperechogenic (A), intermediate isoechogenic (B) and multiple-layered "triple-line" (C). Type A had no pregnancies, whereas type B had a 20% fecundity rate and type C had a 21.1% fecundity rate. The continuing pregnancy rate was 10% in type B, as compared to 19.3% in type C. The data suggest that the endometrial sonographic pattern on the day of hCG administration may be of predictive value regarding fecundity and continuing pregnancy in the intrauterine insemination cycle.

Adult↗
PubMed1995

Prostate cancer incidence in Missouri: an updated analysis.

Prostate cancer incidence increased dramatically in Missouri in the 1990s. However, this study demonstrates that the increased incidence parallels the dramatic increase in the earliest stage of the disease. Increased detection for prostate cancer is believed to play a strong role in this rising incidence. Continued surveillance for prostate cancer is necessary to determine the significance of the sharp rise in the incidence in Missouri.

Adolescent↗