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Biomedical subjects

L H Huang

Publications and source records attributed to L H Huang.

At least 37 records · Page 2Linked to original sources
PubMed1996

Differential effects of progestins and estrogens on long control regions of human papillomavirus types 16 and 18.

We have studied effects of a series of progestins and estrogens on regulation of human papillomavirus (HPV) types 16 and 18 gene expression via long control region (LCR), using a transient expression assay which represented the episomal state of HPVs in precancerous lesions. Results showed that HPV gene expression induced by these steroid analogs were diverse. Gene expression via HPV16-LCR was upregulated 2-3 fold under treatment with 10(-7) M estriol, 17 beta-estradiol, and several progestins including pregnenolone, 17 alpha-hydroxy-progesterone, norethynodrel and cyproterone acetate. However, transcription via HPV18-LCR was not or weakly stimulated by these analogs. Our results can divide these analogs into HPV-enhancing and HPV-nonenhancing groups and accordingly impact the relative risk of individual oral contraceptive ingredient in cervical carcinogenesis.

Base Sequence↗
PubMed1996

Regulated nuclear import of the Drosophila rel protein dorsal: structure-function analysis.

The formation of a gradient of nuclear Dorsal protein in the early Drosophila embryo is the last step in a maternally encoded dorsal-ventral signal transduction pathway. This gradient is formed in response to a ventral signal, which leads to the dissociation of cytoplasmic Dorsal from the I kappa B homolog Cactus. Free Dorsal is then targeted to the nucleus. Dorsal is a Rel-family transcription factor. Signal-dependent nuclear localization characterizes the regulation of Rel proteins. In order to identify regions of Dorsal that are essential for its homodimerization, nuclear targeting, and interaction with Cactus, we have performed an in vivo structure-function analysis. Our results show that all these functions are carried out by regions within the conserved Rel-homology region of Dorsal. The C-terminal divergent half of Dorsal is dispensable for its selective nuclear import. A basic stretch of 6 amino acids at the C terminus of the Rel-homology region is necessary for nuclear localization. This nuclear localization signal is not required for Cactus binding. Removal of the N-terminal 40 amino acids abolished the nuclear import of Dorsal, uncovering a potentially novel function for this highly conserved region.

Animals↗
PubMed1996

A multidimensional model of the antecedents of stress and coping appraisals: an approach to studying patients' perceptions of post cardiac surgery pain and their coping strategies.

Lazarus' stress and coping theory has been recognized as a valued conceptual framework for nursing scholars who are interested in studying their client's experiences of stress and coping. However, little data provide in-depth critiques in concepts, availability and limitations of employing Lazarus' theory in nursing phenomena in Taiwan, nor did data provide culturally sensitive propositions for Taiwanese nursing scholars to better understand their clients' stress experience such as post cardiac surgery pain. In order to help Taiwanese critical care nurses better understand the process of theoretical development while assessing their clients' perceptions of post cardiac surgery pain, the historical perspective of the concept of stress and the core components of Lazarus' theory are examined. Following is a critical critique of Lazarus' theory as a conceptual framework with which to study how patients perceive post cardiac surgery pain as a stressor. A multidimensional model of the antecedents of stress and coping appraisals for nurses to assess their clients' perceptions of pain and the resulting coping behaviors is further developed based on the aforementioned critiques. Finally, suggestions for testing theoretical propositions related to this phenomenon, as well as implications for nursing practice, research, as theory are delineated and discussed.

Cardiac Surgical Procedures↗
PubMed1996

Patients' needs and their coping strategies transition to cardiac surgery.

Little data are available concerning Taiwanese patients' needs and the factors contributing to their needs before cardiac surgery. The purpose of this study was to explore the components, nature and definition of patients' needs and their coping strategies of preparation for cardiac surgery during admission transition from patients' perspectives. The admission transition in this study means the patients' stay in the cardiovascular floor unit before surgery. Thirty adult patients (15 men, 15 women) having cardiac surgery were theoretically sampled from three hospitals in Taipei, Taiwan. Data were obtained through a semi-structured interview with the investigator and were analyzed by employing the combination of strategies from grounded theory, qualitative content analysis, linking data, and constant comparison. Ninety percent of participants expressed two types of needs: certain- including met, unmet and expectant needs, and uncertain needs. Needs that participants believed to have been met were the needs for security, maintaining daily living activities, understanding the surgery and recovery process, the needs for optimal physical condition for surgery, receiving quality treatment, and coaching as to use of medical instruments. The unmet needs were the needs for maintaining daily activities, security, fulfilling unfinished family responsibilities, financial support, understanding the surgery and what to expect during the recovery process, freedom from pain, family members' companionship, and spiritual support. The expectant needs included those needs during the ICU and discharge-preparation recovery transitions, throughout the hospitalization and after recovery. The components, nature, definition, reasons, and suggestions for patients' needs and their coping strategies were delineated and discussed. Finally, a conceptual framework was developed to describe and depict this phenomenon.

Activities of Daily Living↗
PubMed1996

Medication-taking behavior of the elderly.

The aim of this study was to examine the medication-taking behavior of older adults living in communities. Factors influencing their medication-taking behavior were also explored. Data were collected by way of a face-to-face interview survey through a random sample of 401 persons over 65 years of age, and were analyzed using SPSS computer software. The sample included two groups of people, one residing in an urban community and the other in a rural community. The results revealed information on the following kinds of medication behavior: self-medication, using non-prescription medications, sharing medication, forgetting to take medications, misusing medications, being non-compliant, using multi-medications, hoarding medications, and combining Western medications with traditional therapies. In comparing the differences between the urban and rural elderly, the urban elderly had more accurate medication knowledge and displayed better medication-taking behavior. An elderly person's age, gender, education level, marital status, living status and health belief were found to affect his/her medication knowledge and behavior. Education of both health care professionals and the general public is urgently needed to ensure the safety of taking medication by the elderly.

Aged↗
PubMed1995

Expression of a Drosophila GATA transcription factor in multiple tissues in the developing embryos. Identification of homozygous lethal mutants with P-element insertion at the promoter region.

GATA transcription factors are DNA-binding proteins that recognize the core consensus sequence, WGATAR. Previous studies indicated that GATA factors play ann important role in the development of tissue-specific functions in vertebrates. Here we report the identification of a new Drosophila melanogaster GATA factor, dGATAc, which displays a distinct expression pattern in embryos. The local concentration of dGATAc transcripts varies at different stages, being most prominent in the procephalic region at stages 6-10 and in the posterior spiracles, the gut, and the central nervous system at stages 11-13. On the basis of its predicted sequence, DNA-binding assays were performed to confirm that the dGATAc gene encodes a zinc finger protein that can bind the GATA consensus motif with predicted specificity. Two independent mutants carrying a P-element insertion at the dGATAc gene promoter region were identified that are homozygous lethal at the embryonic stage. Using a genetic scheme, it was demonstrated that the lack of dGATAc function can block normal embryonic development. Our results suggest that the dGATAc protein is a tissue-specific transcription factor that is vital to the development of multiple organ systems in D. melanogaster.

Amino Acid Sequence↗
PubMed1995

Generation of novel rapamycin structures by microbial manipulations.

A new rapamycin producing culture was isolated and designated as Actinoplanes sp. N902-109. The addition of a cytochrome P-450 inhibitor and precursor feeding using this culture, and biotransformation approaches generated new rapamycin analogs with modifications at C-4, C-9, C-16, C-27, C-28 and/or C-39. The immunosuppressive activity of the resulting analogs was established in the mixed lymphocyte reaction assay.

Actinomycetales↗
PubMed1994

Interferon activation of the transcription factor Stat91 involves dimerization through SH2-phosphotyrosyl peptide interactions.

Stat91 (a 91 kd protein that acts as a signal transducer and activator of transcription) is inactive in the cytoplasm of untreated cells but is activated by phosphorylation on tyrosine in response to a number of polypeptide ligands, including interferon alpha (IFN-alpha) and IFN-gamma. We report here that the inactive Stat91 in the cytoplasm of untreated cells is a monomer and that upon IFN-gamma-induced phosphorylation it forms a stable homodimer. Only the dimer is capable of binding to a specific DNA sequence directing transcription. Through dissociation and reassociation assays, we show that dimerization of Stat91 is mediated through SH2-phosphotyrosyl peptide interactions. Dimerization involving SH2 recognition of specific phosphotyrosyl peptides may well provide a prototype for interactions among family members of STAT proteins to form different transcription complexes.

Amino Acid Sequence↗
PubMed1992

CP-82,009, a potent polyether anticoccidial related to septamycin and produced by Actinomadura sp.

A new polyether antibiotic CP-82,009 (C49H84O17) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53676). Following purification by column chromatography and crystallization, the structure of CP-82,009 was elucidated by spectroscopic (NMR and MS) methods. The absolute stereochemistry was determined by a single crystal X-ray analysis of the corresponding rubidium salt. CP-82,009 is among the most potent anticoccidial agents known, effectively controlling the Eimeria species that are the major causative agents of chicken coccidiosis at doses of 5 mg/kg or less in feed. It is also active in vitro against certain Gram-positive bacteria, as well as the spirochete, Serpulina (Treponema) hyodysenteriae.

Actinomycetales↗
PubMed1991

Application of ligand-exchange chromatography to the assay of L-alanine from DL-aspartic acid by Pseudomonas dacunhae.

A direct chiral ligand-exchange chromatographic method was developed to monitor L-alanine production by fermentation. A mobile phase containing aqueous 0.25 mM Zn2+ solution is utilized to separate amino acids in the fermentation medium. The detection limit for L-alanine is 0.5 ppm and the analysis time for one sample is about 8 min. As sample preparation is simple and the matrix effects are minimal, the assay is fast and convenient. The results indicate that the method has potential for the analysis of complicated fermentation media.

Alanine↗
PubMed1991

Sequence-specific 1H NMR assignments, secondary structure, and location of the calcium binding site in the first epidermal growth factor like domain of blood coagulation factor IX.

Factor IX is a blood clotting protein that contains three regions, including a gamma-carboxyglutamic acid (Gla) domain, two tandemly connected epidermal growth factor like (EGF-like) domains, and a serine protease region. The protein exhibits a high-affinity calcium binding site in the first EGF-like domain, in addition to calcium binding in the Gla domain. The first EGF-like domain, factor IX (45-87), has been synthesized. Sequence-specific resonance assignment of the peptide has been made by using 2D NMR techniques, and its secondary structure has been determined. The protein is found to have two antiparallel beta-sheets, and preliminary distance geometry calculations indicate that the protein has two domains, separated by Trp28, with the overall structure being similar to that of EGF. An NMR investigation of the calcium-bound first EGF-like domain indicates the presence and location of a calcium binding site involving residues on both strands of one of the beta-sheets as well as the N-terminal region of the peptide. These results suggest that calcium binding in the first EGF-like domain could induce long-range (possibly interdomain) conformational changes in factor IX, rather than causing structural alterations in the EGF-like domain itself.

1-Carboxyglutamic Acid↗
PubMed1991

Substituent effects on the binding constants of arsenical-dithiol adducts.

Proton nuclear magnetic resonance spectroscopy (1H NMR) was used to determine the relative binding constants for several arsenical-dithiol adducts. The compounds investigated were 2,3-dimercaptopropanol (British anti-lewisite; BAL), 1,2-ethane dithiol (ET), and 1,2-propane dithiol (PDT). It was found that PDT has a significantly higher affinity than ET or BAL for phenyldichloroarsine (PDA) in methanol.

Arsenicals↗
PubMed1990

A simple method to create carotid endothelial laceration and acute platelet thrombus in vivo in guinea-pig.

A simple method, named 'clamp method', was developed to create carotid endothelial laceration and produce acute platelet thrombus in vivo in guinea-pig. This method used a hemostatic forceps to clamp common carotid artery of anesthetized guinea-pig at a tangent angle. Our study included two parts. The Part one demonstrated the procedures and effects of the 'clamp method': sixteen guinea-pigs were divided equally into control and heparin-treated groups. These two groups received the same clamping procedures except that the heparin-treated group was administrated with heparin (5,000U/kg) intravenously before clamping. One hour after the clamping, carotid arteries were resected and observed under scanning electron microscopy. The results showed that large carotid mural thrombi were formed in the control group with a mean surface area of 1.75 +/- 0.63 mm2 (M +/- SD, n = 8). In the heparin-treated group, the thrombus formation was prevented and linear endothelial lacerations were seen clearly. The Part two of our study identified the histologic nature of the thrombus produced by the 'clamp method': eight guinea-pigs received same procedures as that of control group in the Part one except that the carotid arteries were resected 5 min after performing the clamping. Four of the eight specimens were prepared for observation under transmission electron microscopy. The results showed that platelets adhered onto the subendothelial substances and formed platelet thrombi in the endothelial lacerations within 5 min after the carotid clamping.

Animals↗
PubMed1990

CP-82,996, a novel diglycoside polyether antibiotic related to monensin and produced by Actinomadura sp.

A new polyether antibiotic CP-82,996 (C50H86O16) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53764). Following purification by silica gel column chromatography and crystallization, the structure of CP-82,996 was determined by a single crystal X-ray analysis. The structure is closely related to monensin, but is unique in that it contains two sugar groups, whereas monensin has none. The 1H and 13C NMR chemical shifts and assignments for CP-82,996 were elucidated, and they were compared with those determined previously for monensin. CP-82,996 is active against certain Gram-positive bacteria, and is a very potent anticoccidial agent. It effectively controlled chicken coccidiosis caused by several Eimeria species at 5-10 ppm in feed, and is 10-20 times more potent than monensin.

Animals↗
PubMed1990

CP-60,993, a new dianemycin-like ionophore produced by Streptomyces hygroscopicus ATCC 39305: fermentation, isolation and characterization.

CP-60,993, 19-epi-dianemycin, is a novel polycyclic ether antibiotic produced by Streptomyces hygroscopicus ATCC 39305. Fermentation recovery, purification and crystallization were achieved using standard procedures. CP-60,993 was characterized as a monocarboxylic acid. Elemental analysis suggested a molecular formula of C47H78O14 for the free acid and C47H77O14 Na for the sodium salt. Crystalline from CP-60,993 sodium salt shows the following properties: m.p. 193-205 degrees C, E1%(1 cm) = 157 at 232 nm, [alpha]25 degrees C(D) + 11.0 (c 1, methanol). The structure, determined by MS, PMR and CMR, differs from dianemycin only in the stereochemistry at position 19. This was confirmed by X-ray crystallography carried out on the rubidium salt of CP-60,993. It exhibited activity in vitro against Gram-positive and anaerobic bacteria, efficacy against Eimeria coccidia in vivo in poultry, and stimulation in vitro of rumen propionic acid production.

Aminoglycosides↗