Search PubMed⌕ Search

Biomedical subjects

A S Chang

Publications and source records attributed to A S Chang.

At least 55 records · Page 3Linked to original sources
PubMed1991

Self-care burden, stress appraisal, and mood among persons receiving radiotherapy.

This study was undertaken to describe the self-care burden (SCB) of persons receiving radiation as outpatients, to identify factors contributing to SCB, and to test a model of the effects of SCB, symptom distress, and appraisal of illness on mood. The subjects were 72 adults with cancer who had been in treatment an average of 4 weeks. Fatigue was reported to be the most distressing symptom. Among health deviation self-care tasks, coming for treatment was the most demanding, and self-treatment, such as administering medications, was the most difficult. Universal self-care activities most disrupted by treatment were social and recreational activities. Path analysis revealed that dependency was the primary predictor of health deviation SCB, while symptom distress was the best predictor of universal SCB. Universal SCB and family hardiness were the best predictors of appraisal scores. Symptom distress and somatic mood were highly correlated, suggesting collinearity between these factors. Four variables--appraisal, symptom distress, family hardiness, and health deviation SCB--explained 55% of the variance in affective mood scores. Theoretical and clinical implications are discussed.

Activities of Daily Living↗
PubMed1990

Reading activities of registered nurses.

This national study was designed to gather baseline data about the reading activities of registered nurses. Questionnaires were administered by nurse continuing educators to subjects (N = 1406) at 44 sites in 25 states and the District of Columbia. In a week, the mean amount of time devoted to professional literature was four hours, 48 minutes (SD = 3.88) plus eight hours, 12 minutes (SD = 5.15) to general material. This translated to reading one hour and 51 minutes per day, slightly more than the average adult. Educational level, position, and memberships were the best predictors of how much time was spent reading job-related material that might lead to self-development and enhancement of nursing practice.

Adult↗
PubMed1989

What being the parent of a new baby is like: revision of an instrument.

Revision of the self-report instrument, What Being the Parent of a New Baby Is Like (WPL), is reported. The WPL, developed to examine parents' perceptions of themselves as parents and of the parenting experience with young infants, was revised by improving its two subscales, Success (renamed Evaluation) and Centrality, and adding a third subscale, Life Change. With a sample of mothers of healthy infants, all three subscales of the revised instrument, WPL-R, had acceptable levels of internal consistency at 7, 30, and 90 days postpartum, and stability across administrations. Parity differences were demonstrated for all three subscales at 7 days and for Centrality at 30 days. Factor analysis identified item clusters consistent with the three subscales. With improved subscales affording a more comprehensive assessment of maternal experience, the WPL-R is a better instrument for evaluation of maternal adaptation than the WPL.

Adaptation, Psychological↗
PubMed1989

Characterization of a genetically reconstituted high-affinity system for serotonin transport.

By transfecting mouse fibroblast L-M cells with human genomic DNA, we have established and identified several clonal cell lines that stably express a high-affinity serotonin (5-HT)-uptake mechanism absent in untransfected host cells. One such cell line, L-S1, possesses features of 5-[3H]HT uptake similar to those previously characterized in the central nervous system and blood platelets: (i) specificity for 5-HT; (ii) antagonism by imipramine, a known inhibitor of high-affinity 5-HT uptake; (iii) both Na+ and temperature dependences; (iv) kinetic saturability; and (v) high affinity for 5-HT (Km = 0.39 +/- 0.10 microM; Vmax = 2.14 +/- 0.55 pmol/min per mg of protein). This cell line can be used to compare the relative efficacies of known blockers of 5-HT uptake and thereby offers a rapid and reliable assay system for testing novel inhibitors of this system. Since L-S1 contains stably integrated human DNA in its genome, we postulate that the observed 5-HT-uptake system resulted from the expression of human gene(s) coding for the 5-HT transporter. Thus, cell lines such as L-S1 may represent novel means for screening and developing therapeutic agents specific for neurotransmitter-uptake systems as well as substrates for the cloning and elucidation of the genes encoding the various neurotransmitter transporters.

Animals↗
PubMed1987

Mothers' problem-solving skill and use of help with infant-related issues: the role of importance and need for action.

Examination was made of the relationship of mothers' appraisal of the importance of and need for action around infant-related issues to maternal experience (parity and time since birth), use of help, and perceived problem-solving competence. Sixty-two mothers (38 primiparae and 24 multiparae) kept for 90 days post-birth a daily log of issues, rated for importance and for need for action, and of help used. Mothers also reported perceived problem-solving competence on an 11-item scale. Findings indicated tentativeness in ratings of importance and action. Ratings of importance were associated with action ratings, except for temperament issues. Action ratings for baby care and illness issues decreased significantly with time. Otherwise, maternal experience had no effect on ratings. More of the variance in perceived competence than use of help was explained by action and importance ratings.

Adaptation, Psychological↗
PubMed1985

Parents' beliefs about themselves as parents of a new infant: instrument development.

The instrument, What Being the Parent of a New Baby is Like (WPL), was designed to assess parental experiences and self-images which are likely to influence problem-solving concerning their infants. Forty-nine mothers responded to the questionnaire on three separate occasions during the infants' first 3 months. These data were the basis for a preliminary examination of the item characteristics, reliability (internal consistency), and validity. The pattern of responses to the WPL was in the expected direction for a sample of mothers who, on the whole, functioned well as parents. Principal components factor analysis with iteration and varimax orthogonal rotation identified two variables (centrality of the infant and success in parenting) that together accounted for 60.1% of the variance; adequate internal consistency for success and modest internal consistency for centrality were demonstrated. Use of the Neonatal Perception and Degree of Bother Inventories demonstrated divergent validity. Expected parity differences tested the known groups technique of construct validity. The significant relationship between success and a measure of parents' perceptions of their problem-solving skills demonstrated concurrent validity. Further testing of WPL with added items on larger and more heterogeneous samples is warranted.

Adolescent↗
PubMed1984

The gene encoding the beta-subunit of rat luteinizing hormone. Analysis of gene structure and evolution of nucleotide sequence.

The nucleotide sequence of the gene encoding the beta-subunit of rat luteinizing hormone (LH beta) has been determined from a genomic DNA fragment cloned in lambda phage Charon 4A. Blot hybridization of restriction enzyme digests of rat genomic DNA indicates that the gene is present in a single copy. The transcriptional unit is 0.98 kilobase in size and contains three exons interrupted by two introns of 245 and 225 base pairs (bp). The locations of the exon/intron junctions at amino acid codons -16/-15 and +41/+42 have been conserved between the rat LH beta gene and the related genes, human LH beta and human chorionic gonadotropin beta. Using S1 nuclease mapping and oligonucleotide-primed reverse transcription of ovariectomized rat pituitary mRNA, the start of transcription was determined to be 7 bp upstream from the start of translation. Characteristic promoter elements are present in the 5'-flanking region of the gene, including the Goldberg-Hogness sequence, TATAAA, 31 bp, and the consensus CAAT box sequence, 167 bp upstream from the start of transcription, respectively. Within the proximal 200 bp flanking the 5'-region of the transcriptional unit, there is strong homology between the rat and human LH beta genes, suggesting that these regions include sequences which may be important for regulation of gene expression. Isolation and characterization of the rat LH beta gene further defines the evolution of glycoprotein hormone genes and will facilitate the study of cellular and molecular mechanisms which regulate LH beta gene expression.

Amino Acid Sequence↗
PubMed1983

Nucleotide sequence of the cDNA encoding the precursor of the beta subunit of rat lutropin.

We have determined the nucleotide sequences of cDNAs encoding the precursor of the beta subunit of rat lutropin, a polypeptide hormone that regulates gonadal function, including the development of gametes and the production of steroid sex hormones. The cDNAs were prepared from poly(A)+ RNA derived from the pituitary glands of rats 4 weeks after ovariectomy and were cloned in bacterial plasmids. Bacterial colonies containing transfected plasmids were screened by hybridization with a 32P-labeled cDNA encoding the beta subunit of human chorionic gonadotropin, a protein that is related in structure to lutropin. Several recombinant plasmids were detected that by nucleotide sequence analyses contained coding sequences for the precursor of the beta subunit of lutropin. Complete determination of the nucleotide sequences of these cDNAs, as well as of cDNA reverse-transcribed from pituitary poly(A)+ RNA by using a synthetic pentadecanucleotide as a primer of RNA, provided the entire 141-codon sequence of the precursor of the beta subunit of rat lutropin. The precursor consists of a 20 amino acid leader (signal) peptide and an apoprotein of 121 amino acids. The amino acid sequence of the rat lutropin beta subunit shows similarity to the beta subunits of the ovine/bovine, porcine, and human lutropins (81, 86, and 74% of amino acids identical, respectively). Blot hybridization of pituitary RNAs separated by electrophoresis on agarose gels showed that the mRNA encoding the lutropin beta subunit consists of approximately 700 bases. The availability of cDNAs for both the alpha and beta subunits of lutropin will facilitate studies of the regulation of lutropin expression.

Amino Acid Sequence↗
PubMedDate not supplied

Topical capsaicin for chronic neck pain. A pilot study.

Substance P is thought to be the principle neurotransmitter of nociceptive impulses in type C sensory neurons. Prolonged repeated applications of capsaicin cream depletes the sensory C-fibers of substance P. In an open-labeled prospective pilot study, 23 patients with chronic neck pain (greater than 3 mo) completed the study. Patients applied topical capsaicin (0.025%) cream four times a day to painful areas in the neck and shoulder girdle for a 5-wk treatment period. One patient dropped out because of intolerable burning. Statistically significant improvement was obtained in two primary outcome variables, the visual analog pain scale (P = 0.00013) and the pain relief scale (P = 0.002). Paired t tests failed to show a significant improvement in the McGill Pain Questionnaire. This study demonstrated that topically applied capsaicin cream may decrease subjective neck pain. A double-blind, placebo-controlled trial is needed to confirm this treatment effect.

Administration, Topical↗
PubMedDate not supplied

Statistical methods of computing reference values for side-to-side differences in nerve conduction studies.

This study uses theoretic derivations, statistical simulations, and empirical estimations to compare two ways of deriving reference values for side-to-side differences in nerve conduction parameters of healthy subjects. The two methods involve using the side-to-side differences (STSD) and the absolute values of the STSD (AVSTSD). The theoretic derivations showed that the population reference value of the AVSTSD is greater than the STSD reference values by 0.18%. Simulation studies showed that the AVSTSD yields greater sampling errors than the STSD method when establishing the reference values for nerve conduction parameters. However, the sampling variability is substantially reduced by using study samples of greater than 50, and the differences between the two methods in sampling errors are trivial as sample size approaches 100. Using H reflex (HR) and extensor digitorum brevis reflex (EDBR) clinical data, the two methods were compared. In contrast to the small theoretic differences in reference values, the AVSTSD method overestimated the reference value by 0.5 ms for the EDBR and 0.1 ms for the H reflex, when using data from a population sample, increasing the type II error (reducing sensitivity) for the EDBR. The STSD method is recommended for establishment of normal values and for clinical comparisons.

Electromyography↗
PubMedDate not supplied

Polytetrafluoroethylene hemoaccess site infections.

The advent of permanent hemodialysis access has made possible the use of chronic hemodialysis in patients with end-stage renal disease. Although autogenous arteriovenous fistulae remain the conduit of choice, their construction is not always feasible. Prosthetic grafts made of polytetrafluoroethylene (PTFE) are typically the second-line choice for hemoaccess. However, these grafts suffer from decreased rates of patency and an increased number of complications. Although thrombosis is the most common complication, infection of PTFE grafts accounts for a significant number of hospitalizations and uses a large amount of healthcare resources. In this monograph, we address infectious complications of PTFE hemoaccess grafts and present a review of the recent literature.

Biocompatible Materials↗
PubMedDate not supplied

Interleukin-1 beta, interleukin-5, interleukin-6, interleukin-8, and tumor necrosis factor-alpha in chronic sinusitis: response to systemic corticosteroids.

Recently, the role of various cytokines in the pathogenesis of chronic rhinosinusitis has come under investigation. Various studies have reported increased levels of interleukin-3, interleukin-4, interleukin-5, interleukin-13, and granulocyte macrophage-colony stimulating factor in the sinonasal mucosa of patients with chronic rhinosinusitis. The present study investigated the levels of pro-inflammatory cytokines, including interleukin-1 beta (IL-1 beta), interleukin-5 (IL-5), interleukin-6 (IL-6) interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha), in the sinonasal mucosa of patients with chronic rhinosinusitis, and evaluated the response of these cytokines to oral corticosteroids. Chronic rhinosinusitis subjects (n = 15) and control subjects (n = 9) underwent nasal endoscopy and biopsy of the sinonasal mucosa. Chronic rhinosinusitis subjects were subsequently treated with a 10-day tapering dose of prednisone followed by a second sinonasal endoscopic exam and biopsy. Mucosal biopsy specimens were immunostained for IL-1 beta, IL-5, IL-6, IL-8, and TNF-a. In chronic rhinosinusitis subjects, mucosal levels of IL-1 beta, IL-6, IL-8, and TNF-alpha were significantly elevated when compared with control subjects, and levels of IL-5 demonstrated a strong trend toward elevation. In posttreatment chronic rhinosinusitis subjects, levels of IL-6 were significantly decreased when compared with pretreatment levels, and TNF-alpha levels demonstrated a significant trend toward reduction. These findings support the hypothesis that the inflammatory response in chronic rhinosinusitis is associated with elevated levels of pro-inflammatory cytokines, and suggest that oral corticosteroids may exert a beneficial effect by significantly reducing the levels of IL-6 and TNF-alpha.

Administration, Oral↗
PubMedDate not supplied

Hepatitis B virus e antigen and primary hepatocellular carcinoma.

Serum samples from 243 cases of primary hepatocellular carcinoma (PHC) and 302 non-PHC hospital controls were tested for hepatitis B virus (HBV) surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to HBV core antigen (anti-HBc), HBV e antigen (HBeAg) and antibody to HBeAg (anti-HBe) with radioimmunoassays using commercial kits. A total of 236 (97%) PHC cases and 302 (100%) hospital controls were positive for one or more HBV markers. While 188 (77%) PHC cases and 57 (19%) controls were positive for HBsAg, 44 (18%) PHC cases and 5 (2%) controls were positive for both BHsAg and HBeAg. Statistically significant associations with PHC were observed for HBsAg and HBeAg with an odds ratio (OR) of 10.0 and 3.2, respectively, when age, sex and other markers were adjusted. The stratification analysis of interactive effects of HBV infection markers on the development of PHC showed that HBeAg carrier status may increase PHC risk associated with HBsAg status.

Adult↗
PubMedDate not supplied

Stereochemical differences in the metabolism of 3,4-methylenedioxymethamphetamine in vivo and in vitro: a pharmacokinetic analysis.

The in vivo N-demethylation of (+) and (-)3,4-methylenedioxymethamphetamine (MDMA) to 3,4-methylenedioxyamphetamine (MDA) was determined and the pharmacokinetic relationship between the two compounds calculated. The levels of MDA formed after iv administration of (+)MDMA to male rats were about 3 times greater than those for (-)MDMA, although the plasma levels of the parent drugs were comparable. Plasma MDA concentrations were lower in phenobarbital-pretreated rats, but SKF 525-A pretreatment, at the dose used, had minimal effects. In liver microsome experiments conducted with microM concentrations of (+)MDMA, 3,4-dihydroxymethamphetamine (N-methyl-alpha-methyldopamine) was shown to be the major metabolite. MDA was also formed in vitro, but the enantioselectivity was the opposite of that found in vivo, pointing out the difficulties in extrapolation of in vitro observations to in vivo disposition. The high levels of MDA observed after administration of (+)MDMA to intact animals suggest that this active metabolite could be important in the overall effects of (+)MDMA.

3,4-Methylenedioxyamphetamine↗
PubMedDate not supplied

Epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan.

Both descriptive and analytical studies were carried out to examine epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan. The age-adjusted mortality rate of stomach cancer has been decreasing since the early 1970s for both males and females. The male-to-female ratio of the disease has remained around 2:1 in the past three decades. Comparison of the incidence of stomach cancer among Chinese in different countries showed a much lower incidence among Chinese in the USA than those in southeastern Asia. A hospital-based matched case-control study carried out in Taipei metropolitan areas showed a positive association of stomach cancer with blood type A, chronic gastric diseases, cigarette smoking, alcohol drinking, green tea drinking as well as consumption of salted meat, cured meat, smoked food, fried food and fermented beans. There was also a significant negative association between the disease and the consumption of milk.

Alcohol Drinking↗