Biomedical subjects

R Y Huang

Publications and source records attributed to R Y Huang.

At least 19 recordsLinked to original sources

PubMed2002

Characterization of bone mineral composition in the proximal tibia of cynomolgus monkeys: effect of ovariectomy and nandrolone decanoate treatment.

Life postmenopausal women, ovariectomized cynomolgus monkeys (Macaca fascicularis) experience accelerated loss of bone mass. Treatment of ovariectomized monkeys with nandrolone decanoate results in an increase in bone mass to levels comparable to those of intact animals. The changes in bone composition that occur with these treatments, however, are less well characterized. In the present study, we used synchrotron Fourier-transform infrared microspectroscopy (FT-IRM) and curve-fitting methods to monitor specific changes at cortical, subchondral, and trabecular bone regions in the proximal tibia. Four groups were studied: (1) sham-operated (sham); (2) ovariectomized and treated with placebo for 2 years (ovx); (3) ovx + nandrolone decanoate for 2 years (NAN); and (4) ovx + nandrolone decanoate beginning 1 year after ovx (dNAN). The results demonstrate that ovariectomy and nandrolone treatment did not affect the degree of mineralization as defined by the phosphate/protein ratio, but acid phosphate content (HPO(4)(2-)) in cortical and subchondral bone was increased by ovariectomy, suggesting this bone to be less mature due to increased remodeling that occurs after ovariectomy. In the subchondral and cortical bone regions, ovariectomized monkeys showed a lower total carbonate content (CO(3)(2-)/matrix ratio) than sham controls, specifically due to the decrease in labile carbonate content. In the trabecular region, no change of carbonate content was observed. Treatment with nandrolone decanoate was found to restore the loss in carbonate, where the resulting mineral had a larger quantity of type B carbonate. Finally, we correlated carbonate content with dual-energy X-ray absorptiometry measurements, and found a positive correlation between bone mineral density and type A carbonate in bone, which is stoichiometrically related to the amount of calcium in bone. Therefore, the results presented herein identify significant differences in bone chemistry after ovariectomy and nandrolone treatment, which may help explain previous findings that, although nandrolone decanoate treatment increased bone mass, it could not reverse the decrease in bone strength due to ovariectomy.

Anabolic Agents↗

PubMed2001

Differential expression of integrin mRNAs and proteins during normal rat mammary gland development and in carcinogenesis.

A rat model was used to address the roles of integrins in the regulation of normal mammary epithelial cell (MEC) growth and differentiation and in mammary carcinogenesis. The expression of integrins alpha5, alpha6, beta1, and beta4 was examined via Northern and Western blotting analyses in freshly isolated MEC from various postnatal developmental stages. mRNAs for all four integrins were detectable at puberty and were increased during pregnancy. During lactation, the expression of alpha5, alpha6, and beta1 integrin mRNAs reached a peak, whereas that of beta4 integrin decreased dramatically. At day 7 of involution, the levels of all four integrin mRNAs were similar to or slightly higher than that of the pubertal mammary gland. Although alpha5 integrin protein decreased during pregnancy and lactation, beta1 and beta4 integrin proteins had similar profiles as the expression of their respective mRNAs, suggesting that integrin gene expression is regulated at both transcriptional and post-transcriptional levels. All four integrins were heterogeneously expressed in 7,12-dimethylbenz[a]anthracene- and N-nitroso-N-methyl-urea-induced mammary tumors and in RBA and NMU rat mammary tumor cell lines. Adhesion assays showed that isolated MEC interacted with fibronectin to a greater extent than with laminin and collagen I in vitro, and that tumor cells with altered integrin expression exhibited greater adhesive ability to various substrata. Together, our results indicate that alpha5, alpha6, beta1, and beta4 integrins are differentially expressed during normal MEC development and in mammary tumors, supporting the hypothesis that these integrins play important yet complex roles in the mammary gland.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2001

Adenotonsillar histopathology after organ transplantation.

OBJECTIVES: The increasing number of surviving pediatric organ transplant recipients has resulted in a new clinical controversy surrounding the significance of adenotonsillar hypertrophy. The objective of this study is to evaluate adenotonsillar specimens, understand characteristic histopathology, and to examine the frequency and significance of this finding in this population. METHODS: Twenty-one cases of pediatric transplant recipients with adenoidal and/or tonsillar hypertrophy were reviewed retrospectively in a tertiary-care setting. Particular attention was given to the histopathology of their surgical specimens, including any evidence of posttransplantation lymphoproliferative disorders (PTLD). RESULTS: Using morphologic, immunohistochemical, and molecular genetic analyses, 15 (71%) of 21 patients were noted to have Epstein-Barr virus (EBV)-related lymphoid hyperplasia, including 1 case (4.7%) of PTLD. Six (29%) of 21 had evidence of reactive follicular hyperplasia not related to EBV. B-cell and T-cell markers were nearly uniformly positive when tested for, except in the single patient with PTLD, who exhibited polymorphic, polyclonal B-cell morphology. Kappa and lambda light-chain clonality markers were positive in 11 (92%) of 12 patients. CONCLUSIONS: EBV-related lymphoid hyperplasia is frequently associated with adenotonsillar hypertrophy in pediatric organ transplant patients (71% of our cases); 92% of those cases tested exhibit polyclonal B-cell populations. PTLD, an important cause of morbidity and mortality in this population, represented approximately 5% of our cases. The remainder of cases represent follicular hyperplasia unrelated to EBV or lymphoproliferative abnormalities. Characteristic histopathologic findings are presented.

Adenoids↗

PubMed2001

Mouse ST6Gal sialyltransferase gene expression during mammary gland lactation.

The sialyltransferase ST6Gal mediates the biosynthetic addition of sialic acid, via an alpha2,6 linkage, to the nonreducing end of terminal lactosamine structures. Transcription of the murine ST6Gal gene, Siat1, is regulated by the selective use of multiple promoters in a tissue- and development-specific manner. Here we report that Siat1 mRNA expression is dramatically elevated in lactating (relative to virgin) mouse mammary gland. The predominant ST6Gal mRNA species expressed in lactating mammary gland is a heretofore undocumented isoform containing a unique 5'-untranslated region originating from the mouse Siat1 genetic region, now defined as Exon L, residing 549-bp 5' of the previously characterized Exon X(2). Thus, the novel ST6Gal mRNA form initiates transcription from the region designated as p4 and incorporates the unique sequence from Exon L in 5'-juxtaposition to commonly shared sequences encoded on Exon I to Exon VI. In contrast, cells derived from virgin mammary tissue expressed only the housekeeping mRNA form derived from p3, with Exon O sequence preceding Exons I-VI. The Exon L-containing, p4 class of mRNA was also not detected in a survey of eight other mouse tissues. Previous reports have indicated a strong correlation between mammary cancers and elevated ST6Gal expression in rats and in human patients. However, we uncovered neither elevated expression of ST6Gal mRNA nor appearance of p4 class in mouse breast carcinomas experimentally induced by transformation with the polyoma-middle T oncogene. A number of established breast carcinoma cell lines were also examined, with ST6Gal mRNA and activity generally low. Moreover, with the exception of the Shionogi cell line, p4 class of ST6Gal mRNA was not expressed in any of the mouse breast carcinoma specimens examined. Taken together, our data indicate that murine ST6Gal induction during lactation is achieved by de novo recruitment of a normally silent promoter. Furthermore, the data provide no support for elevated Siat1 expression on the mRNA level in association with murine mammary gland carcinogenesis. With the single exception of the Shionogi cell line, the p3 class remains the predominant ST6Gal mRNA expressed in all other murine mammary carcinoma cells examined.

5' Untranslated Regions↗

PubMed2001

Lack of evoked laryngeal electromyography response in patients with a clinical diagnosis of vocal cord paralysis.

There has been recent debate about whether patients with vocal cord immobility have a neurologic paralysis or whether synkinesis, the misdirection of axons to competing laryngeal muscles, is responsible for the lack of voluntary vocal cord motion. This issue was studied in 15 patients with vocal cord paralysis who underwent laryngeal reinnervation. Evoked electromyography was performed with a surface electrode endotracheal tube. The recurrent laryngeal nerve (RLN) was identified and stimulated with constant current. Of the 15 patients, only 1 produced a compound muscle action potential upon nerve stimulation. The remaining 14 patients had no evoked response during RLN stimulation. A control group of 8 patients with normal vocal cord mobility was studied, and each had a normal evoked electromyography response after RLN stimulation. These results support the assertion that patients who require treatment for vocal cord paralysis do not have synkinesis produced by RLN reinnervation.

Adult↗

PubMed2001

Influence of pH on the dewatering of activated sludge by Fenton's reagent.

The specific filtration resistance, moisture, and SVI were used to evaluate the influence of pH on the filtration and dewatering efficiencies when applying Fenton's reagent to treat the excess sludge. The excess sludge used in this study was obtained from the wastewater treatment plant of An-Ping Industrial Park in Tainan, Taiwan. Results show that initial pH has no significant effect on the filtration efficiency of sludge by using the Fenton (Fe2+/H2O2) system as the treatment process. However, the reduction of specific resistance by Fenton-like (Fe3+/H2O2) process decreased suddenly to a level similar to that obtained from the control experiment at initial pH > 4.5. For the moisture of cake sludge, both Fenton and Fenton-like systems have the same tendency; the moisture of cake sludge increased slightly with increasing the initial pH. The SVI values for Fenton process decreased with increasing the initial pH, but the opposite result was obtained from the Fenton-like and control system; higher pH was not favorable for the sludge settling.

Filtration↗

PubMed2000

Extranasopharyngeal angiofibroma.

Juvenile nasopharyngeal angiofibromas are vascular neoplasms, which originate characteristically in the posterior lateral wall of the nasopharynx. Although angiofibromas extend beyond the nasopharynx commonly, they rarely originate outside the nasopharynx. Reports of primary extranasopharyngeal angiofibromas have appeared sporadically in the literature. We present an unusual case of an angiofibroma arising from the middle turbinate. The clinical characteristics of extranasopharyngeal angiofibromas do not conform to that of nasopharyngeal angiofibromas. Therefore, they can present diagnostic challenges. A methodic evaluation and a high index of suspicion are essential in establishing the proper diagnosis and treatment.

Adolescent↗

PubMed2000

Third branchial cleft anomaly presenting as a retropharyngeal abscess.

Branchial cleft anomalies are congenital developmental defects that typically present as a soft fluctuant mass or fistulous tract along the anterior border of the sternocleidomastoid muscle. However, branchial anomalies can manifest atypically, presenting diagnostic and therapeutic challenges. Error or delay in diagnosis can lead to complications, recurrences, and even life-threatening emergencies. We describe a case of an infected branchial cleft cyst that progressed to a retropharyngeal abscess in a 5-week-old female patient. The clinical, radiographic, and histologic findings of this rare presentation of branchial cleft cyst are discussed.

Anti-Bacterial Agents↗

PubMed2000

Tracheal stenosis and congenital heart disease in patients with Down syndrome: diagnostic approach and surgical options.

Upper airway obstruction is a prevalent feature in patients with Down syndrome. However, these patients may be completely asymptomatic in the early months of life. The recognition of a problem within the airway quite often occurs when these children present for cardiac surgery, diagnostic radiography with sedation, or during the induction and intubation for anesthesia. Tracheal stenosis is rare in the general population, but is seen somewhat more frequently in patients with Down syndrome. The incidence of tracheal stenosis in children with congenital heart disease, which is seen in 40% of patients with Down syndrome, has been reported to be 1.2%. Patients with Down syndrome also tend to have other upper airway obstructive pathology such as nasopharyngeal, oropharyngeal, and subglottic compromise. These entities, combined with the high incidence of cardiac disease, put these children at risk for acute and chronic cardiopulmonary compromise. We present two patients with Down syndrome and congenital heart disease who were found to have significant tracheal stenosis at the time of their cardiac surgery. The perioperative management of their airway defects including diagnostic evaluation and treatment modalities are discussed.

Cardiac Surgical Procedures↗

PubMed2000

Adenotonsillar enlargement in pediatric patients following solid organ transplantation.

OBJECTIVE: To evaluate the management of adenotonsillar hypertrophy in pediatric patients after transplantation. DESIGN: A retrospective medical record review after transplantation of all pediatric patients undergoing adenotonsillectomy at the University of California, Los Angeles, Medical Center during a 14-month period. SETTING: A tertiary care center. PATIENTS: There were 16 patients in our review, 11 boys and 5 girls. Nine patients had undergone liver transplantation, and 7 had undergone kidney transplantation. INTERVENTION: Fourteen patients underwent adenotonsillectomy, and 2 underwent adenoidectomy alone. Indications for surgical intervention included progressive symptoms of upper airway obstruction, recurrent tonsillitis, and/or evidence of notable adenotonsillar enlargement on physical examination. RESULTS: The mean +/- SD age at the time of transplantation was 3 years 1 month +/- 3 years 5 months. The mean +/- SD duration from allograft transplantation to adenotonsillectomy was 5 years 1 month +/- 2 years 4 months. Histopathologic examination revealed that 1 kidney transplant recipient had posttransplantation lymphoproliferative disorder. Eleven patients were found to have Epstein-Barr virus-related lymphoid hyperplasia. All patients experienced clinical resolution of their symptoms after surgery. CONCLUSIONS: Posttransplantation lymphoproliferative disorder is a condition associated with the Epstein-Barr virus infection in the setting of immunosuppression. Early presentation of posttransplantation lymphoproliferative disorder in children may be manifested by adenotonsillar enlargement. In addition to the role in relieving upper airway obstruction and decreasing upper respiratory tract infection, adenotonsillectomy may be critical in the prompt evaluation and treatment of posttransplantation lymphoproliferative disorder.

Adenoids↗

PubMed2000

Murine B cell differentiation is accompanied by programmed expression of multiple novel beta-galactoside alpha2, 6-sialyltransferase mRNA forms.

ST6Gal I (beta-galactoside alpha2,6-sialyltransferase, ST6N) elaborates the ubiquitously expressed alpha2,6-sialyl linkage. A number of ST6Gal I mRNA isoforms, differing only in their 5'-UT regions, is transcribed from a single mouse gene, Siat1. In B-lineage cells, alpha2,6-sialic acid serves as extracellular ligand for CD22, a participant in cell activation via an intracellular signaling network of tyrosine kinases and SHP phosphastase. Activation and terminal differentiation of mature B cells into plasma cells is accompanied by the appearance of at least four distinct ST6Gal I mRNA isoforms. Resting splenic B-lymphocytes isolated from 8-12 wk C56Bl/6 mice expressed almost exclusively the Exons Q+O-containing form, which is the likely homolog to the previously documented human Y+Z and rat -1+0 forms. In vitro activation using recombinant CD40-ligand and conditioned media from T-helper cells resulted in a 2- to 3-fold elevation of overall ST6Gal I mRNA abundance by Day 3. This coincided with repression of the Q+O form, and appearance of three new isoforms containing 5'-untranslated sequences X(1), X(2), or X(3). The X(1)form persisted through Day 10, when the transition of B cells to plasma cells was completed as evidence by disappearance of CD22 mRNA. In contrast, the X(2)form only transiently appeared at Day 3 and declined to barely detectable levels by Day 7. Expression of the X(3)form, a minor mRNA form, paralleled the X(2)form. The divergent 5'-UT exons are dispersed over 69 kb of linear genomic space of Siat1. Mutually exclusive utilization of these 5'-UT exons in transcripts predicts separate and distinct promoter regulatory regions for each mRNA isoform.

Animals↗

PubMed2000

Changes in ErbB2 (her-2/neu), ErbB3, and ErbB4 during growth, differentiation, and apoptosis of normal rat mammary epithelial cells.

Studies were undertaken to examine the natural role of ErbB2, ErbB3, and ErbB4 during the development of normal rat mammary epithelial cells (MECs) in vivo and in vitro. Immunohistochemical analysis demonstrated that mammary gland terminal end buds expressed abundant ErbB2 and ErbB4 but limited ErbB3 in pubescent rats, whereas luminal epithelial cells in nulliparous rats expressed ErbB2, ErbB3, and/or ErbB4. During pregnancy, ductal epithelial cells and stromal cells expressed abundant ErbB3 but limited ErbB2. Although ErbB2 and ErbB3 were downregulated throughout lactation, both receptors were re-expressed during involution. In contrast, ErbB4 was downregulated throughout pregnancy, lactation, and involution. Immunoblotting and immunoprecipitation studies confirmed the developmental expression of ErbB2 and ErbB3 in the mammary gland and the co-localization of distinct ErbB receptors in the mammary gland of nulliparous rats. In agreement with our in vivo findings, primary culture studies demonstrated that ErbB2 and ErbB3 were expressed in functionally immature, terminally differentiated and apoptotic MECs, and downregulated in functionally differentiated MECs. ErbB receptor signaling was required for epithelial cell growth, functional differentiation, and morphogenesis of immature MECs, and the survival of terminally differentiated MECs. Finally, ErbB4 expression did not interfere with functional differentiation and apoptosis of normal MECs.

Animals↗

PubMed1999

Selective changes in EGF receptor expression and function during the proliferation, differentiation and apoptosis of mammary epithelial cells.

Epidermal growth factor (EGF) is a multifunctional regulator of mammary epithelial cells (MEC) that transduces its signals through the EGF receptor (EGFR). To clarify the role of the EGFR in the mammary gland, EGFR expression, localization and function were examined during different developmental stages in rats. Immunoblot analysis demonstrated high levels of EGFR during puberty, pregnancy and involution as well as at sexual maturity, and low levels throughout lactation. An immunohistochemical assay was used to show that EGFR was distinctly expressed in a variety of cell types throughout mammary glands from virgin rats and rats during pregnancy and involution, and was down-regulated in all cell types throughout lactation. To examine the relationship between EGFR expression and function, primary MEC were cultured under conditions that induced physiologically relevant growth, morphogenesis and lactogenesis. Cultured MEC expressed an in vivo-like profile of EGFR. EGFR was high in immature MEC, down-regulated in functionally differentiated MEC, and then up-regulated in terminally differentiated and apoptotic MEC. An inhibitor of the tyrosine kinase domain of EGFR was used to demonstrate that EGFR signaling was required for growth and differentiation of immature MEC, and for survival of terminally differentiated MEC, but not for maintaining functional differentiation.

Adenocarcinoma↗

PubMed1998

Effect of beta-adrenergic agents on intracellular potential of rabbit ciliary epithelium.

PURPOSE: To study the effects of beta-adrenergic agents on intracellular potential (Vm) of the isolated and intact rabbit ciliary epithelium. METHODS: Vm was measured on the isolated intact ciliary epithelium superfused with adrenergic agents and cyclic AMP modulators. RESULTS: The nonselective beta-adrenergic agonist isoproterenol depolarized Vm in a dose-dependent fashion. beta-adrenergic antagonists alone had no effect on baseline Vm. The isoproterenol response was blocked by the nonselective antagonist timolol (5 x 10(-5) M). The selective beta 2-antagonist ICI 118-551 caused a greater inhibition (IC50 approximately 7 x 10(-7)) than the selective beta 1-antagonist betaxolol (IC50 approximately 6 x 10(-6)). The isoproterenol response was also significantly (p < 0.03) blocked by the non-selective alpha-antagonist phentolamine. Cyclic AMP and phosphodiesterase inhibitors significantly decreased Vm. Pretreatment with these inhibitors potentiated the agonist-induced depolarization. Barium, a blocker of Ca(2+)-sensitive K+ channels, significantly decreased baseline Vm. Barium pretreatment blocked the beta-agonist and cAMP induced depolarization of Vm, suggesting that the K+ current is necessary for the observed isoproterenol response. Pretreatment with the cotransport inhibitor bumetanide had no effect on the isoproterenol-induced response. CONCLUSIONS: The beta-adrenergic agonist isoproterenol affects ionic transport processes across the ciliary epithelium (beta 2 > beta 1). This effect is likely mediated through adenylate cyclase coupled to adrenoreceptors and requires the presence of the K+ current. Blockage of the isoproterenol-induced decrease in Vm by a nonselective alpha-adrenergic antagonist indicates an interaction between the two adrenergic systems in the ciliary epithelium.

Adenylyl Cyclases↗

PubMed1997

[Applying Peplau's theory in improving drug compliance of a schizophrenic patient].

The purpose of this paper is to report the application of Peplau's theory to helping a schizophrenic patient deal with drug noncompliance. It was found that the main reasons for noncompliance were poor insight and lack of illness and drug-related knowledge. Based on Peplau's theory of establishing a therapeutic relationship, giving guidance in medication and monitoring the effects of medication in order to improve drug compliance, the most important role of the nurse is as an assessor and educator. Nurse and patient were able to learn to achieve the common goal of drug compliance through the interactive human relationship.

Adult↗

PubMed1996

Multiple DNA elements in ARS305 determine replication origin activity in a yeast chromosome.

A yeast autonomously replicating sequence, ARS305, shares essential components with a chromosome III replicator, ORI305. Known components include an ARS consensus sequence (ACS) element, presumed to bind the origin recognition complex (ORC), and a broad 3'-flanking sequence which contains a DNA unwinding element. Here linker substitution mutagenesis of ARS305 and analysis of plasmid mitotic stability identified three short sequence elements within the broad 3'-flanking sequence. The major functional element resides directly 3' of the ACS and the two remaining elements reside further downstream, all within non-conserved ARS sequences. To determine the contribution of the elements to replication origin function in the chromosome, selected linker mutations were transplaced into the ORI305 locus and two-dimensional gel electrophoresis was used to analyze replication bubble formation and fork directions. Mutation of the major functional element identified in the plasmid mitotic stability assay inactivated replication origin function in the chromosome. Mutation of each of the two remaining elements diminished both plasmid ARS and chromosomal origin activities to similar levels. Thus multiple DNA elements identified in the plasmid ARS are determinants of replication origin function in the natural context of the chromosome. Comparison with two other genetically defined chromosomal replicators reveals a conservation of functional elements known to bind ORC, but no two replicators are identical in the arrangement of elements downstream of ORC binding elements or in the extent of functional sequences adjacent to the ACS.

Base Sequence↗

PubMed1993

A DNA unwinding element and an ARS consensus comprise a replication origin within a yeast chromosome.

We have defined a replication origin, ORI305, within chromosome III of Saccharomyces cerevisiae by means of mutational analysis. cis-acting elements required for origin activity in the chromosome, as assayed by two-dimensional gel electrophoresis of replication intermediates, are the same as those required for the function of an autonomously replicating sequence, ARS305, in a plasmid. Essential elements include (i) an 11 bp sequence that is a near match to the ARS consensus and (ii) a broad sequence directly 3' to the consensus near match. Origin function is inactivated by point mutations in the essential near match sequence, suggesting that the sequence contributes to specifying the origin in the chromosome. Other consensus near matches with different sequences are present but are not required. The essential 3'-flanking sequence exhibits DNA helical instability and is sensitive to deletion mutations that stabilize the DNA helix. The wild-type 3'-flanking sequence can be functionally substituted by dissimilar sequences that also exhibit helical instability. The requirement for DNA helical instability indicates that the essential 3'-flanking sequence serves as a DNA unwinding element in the chromosome.

Amino Acid Sequence↗

PubMed1993

[Stevens-Johnson syndrome: a review of 42 cases].

We retrospectively studied 42 patients hospitalized for Stevens-Johnson syndrome at the Veterans General Hospital-Taipei between 1979 and 1991. Twenty-seven patients were males and 15 females; the ages ranged from 7 months to 82 years old with a mean age 50. The most common precipitating factor was drugs among which diphenylhydantion was the leading offender followed by nonsteroidal anti-inflammatory agents and allopurinol. Sixteen cases might be etiologically associated with infection, including 13 with upper respiratory infection, one with acute hepatitis B, one with pulmonary tuberculosis, and one with fever of unknown origin that was suspected to be viral infection. Although mycoplasma infection was thought in the literature to be a common etiologic factor of Stevens-Johnson syndrome, it was scarcely found in our study. Four patients were not treated with systemic steroids but still recovered uneventfully. Systemic steroid as a whole was not proved to be necessary, but early large-dose steroid therapy might abbreviate the course of the disease. The mortality rate was 11.9% which differs unremarkably from the reported rate (5-15%). Two patients died of pneumonia with sepsis, one of hemorrhagic shock (bleeding of adenocarcinoma of stomach), one of aspiration pneumonia, and one of sepsis with disseminated intravascular coagulation, upper gastrointestinal bleeding, and hyperglycemic hyperosmolar nonketotic coma.

Adolescent↗