PubMed Health⌕ Search

Biomedical subjects

B Huang

Publications and source records attributed to B Huang.

At least 19 recordsLinked to original sources
PubMed2006

Impaired reproductive fitness in mothers of children with juvenile autoimmune arthropathies.

OBJECTIVE: To assess the reproductive fitness of mothers of children with juvenile idiopathic arthritis (JIA). METHODS: A mail survey assessing pregnancy outcome was carried out among mothers of children with JIA (JIA mothers) treated at a tertiary paediatric rheumatology centre. The best friends of the JIA mothers served as controls. Besides family history, sociodemographics and reproductive outcomes were measured, including the number of pregnancies, pregnancy complications and gestational age at the time of delivery. RESULTS: JIA mothers (n = 227) and controls (n = 235) had similar sociodemographics and racial backgrounds. On average, JIA mothers reported a greater number of conceptions than controls (3.5 vs 3.1; P = 0.01) but had significantly higher rates of pregnancy complications (25% vs 15%; P<0.001). Corrected for differences in the absolute number of pregnancies between groups, the chances of having a miscarriage [mean (s.d.), 0.12 (0.18) vs 0.09 (0.16); P = 0.02] or preterm delivery [0.08 (0.21) vs 0.04 (0.15); P<0.02] were significantly greater among JIA mothers than controls. CONCLUSIONS: Mothers of children with JIA have impaired reproductive fitness. This phenomenon is unlikely to be the result of difficulty with conception but rather to be due to higher rates of pregnancy loss and premature delivery.

Abortion, Spontaneous↗
PubMed2005

Attitudes about human papillomavirus vaccine among family physicians.

STUDY OBJECTIVE: Human papillomavirus (HPV) vaccines will soon be available for clinical use, and the effectiveness of vaccine delivery programs will depend largely upon whether providers recommend the vaccine. The objectives of this study were to examine family physicians' attitudes about HPV immunization and to identify predictors of intention to recommend immunization. DESIGN: Cross-sectional survey instrument assessing provider and practice characteristics, knowledge about HPV, attitudes about HPV vaccination, and intention to administer two hypothetical HPV vaccines. PARTICIPANTS: Surveys were mailed to a national random sample of 1,000 American Academy of Family Physicians (AAFP) members. MAIN OUTCOME MEASURE: Intention to administer two hypothetical HPV vaccines (a cervical cancer/genital wart vaccine and a cervical cancer vaccine) to boys and girls of different ages. RESULTS: One hundred fifty-five surveys (15.5%) were returned and 145 were used in the final sample. Participants reported higher intention to recommend both hypothetical HPV vaccines to girls vs. boys (P < 0.0001) and to older vs. younger adolescents (P < 0.0001). They were more likely to recommend a cervical cancer/genital wart vaccine than a cervical cancer vaccine to boys and girls (P < 0.001). Variables independently associated with intention (P < 0.05) included: female gender of provider, knowledge about HPV, belief that organizations such as the AAFP would endorse vaccination, and fewer perceived barriers to vaccination. CONCLUSIONS: Female gender, knowledge about HPV, and attitudes about vaccination were independently associated with family physicians' intention to recommend HPV vaccines. Vaccination initiatives directed toward family physicians should focus on modifiable predictors of intention to vaccinate, such as HPV knowledge and attitudes about vaccination.

Adolescent↗
PubMed2005

Acceptability of human papillomavirus self testing in female adolescents.

OBJECTIVES: To develop scales assessing acceptability of human papillomavirus (HPV) testing in adolescents, to compare acceptability of self to clinician testing, and to identify adolescent characteristics associated with acceptability. METHODS: Female adolescents 14-21 years of age attending a hospital based teen health centre self collected vaginal samples and a clinician, using a speculum, collected cervicovaginal samples for HPV DNA. Acceptability of and preferences for self and clinician testing were assessed at baseline and 2 week visits. RESULTS: The mean age of the 121 participants was 17.8 years and 82% were black. The acceptability scales demonstrated good internal consistency, reliability, test-retest reliability, and factorial validity. Scores were significantly lower for self testing than clinician testing on the acceptability scale and three subscales measuring trust of the test result, confidence in one's ability to collect a specimen, and perceived effects of testing (p < 0.01). Of those who reported a preference, 73% preferred clinician to self testing. Acceptability scores for both self and clinician testing increased significantly pre-examination to post-examination (p < 0.01). Multivariable analyses demonstrated that race was independently associated with pre-examination and post-examination acceptability of self testing, and that sexual behaviours and gynaecological experiences were associated with specific acceptability subscales. CONCLUSIONS: This sample of adolescents found clinician testing for HPV to be more acceptable than self testing and preferred clinician to self testing. If self testing for HPV is offered in the future, clinicians should not assume that adolescent patients will prefer self testing. Instead, they should educate adolescents about available testing options and discuss any concerns regarding self collection technique or accuracy of test results.

Adolescent↗
PubMed2003

Screening of entomopathogenic Deuteromycetes for activities on targets involved in degenerative diseases of the central nervous system.

A selection of 32 fungal strains, belonging to 8 genera of entomopathogenic Deuteromycetes collected in various provinces of China, were screened for activities on targets involved in degenerative diseases of the central nervous system. The strains were grown under various fermentation conditions, and a total of 256 different extracts were obtained. The bioassays included functional screens for NMDA antagonistic activity in stably transfected fibroblasts, for neuritogenic activities in PC-12 cells, and tests for MAO inhibitory and radical scavenging properties. Several extracts with promising activities were identified. Some Paecilomyces extracts induced pronounced axonal-like outgrowths in PC-12 cells. In Paecilomyces militaris RCEF 0095, the neuritogenic activity could be linked to yellow pigments. Three Beauveria and Paecilomyces strains showed radical scavenging properties, which could be localized in the extract by a bioautographic assay on TLC. An extract obtained from the mycelium of Paecilomyces tenuipes RCEF 0275 showed moderate MAO inhibitory activity, whereas extracts of Sporothrix chondracris RCEF 0187 antagonized NMDA receptor mediated cell toxicity.

Animals↗
PubMed2001

Effect of winter cover crops on soil nitrogen availability, corn yield, and nitrate leaching.

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3 leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha(-1), referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N 0, N 2, and N 3 treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency's drinking water standard of 10 mg N l(-1) even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3 leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

Agriculture↗
PubMed2001

Effect of terminal group sterics and dendron packing on chirality transfer from the central core of a dendrimer.

[structure: see text] The conformational properties of intramolecularly hydrogen-bonded dendrimers constructed from (S)-1,1'-bi-2-naphthol as a chiral central core are described. Circular dichroism studies revealed that chirality transfer to the periphery occurs only when sterically demanding terminal esters are employed and when packing interactions are present.

Journal Article↗
PubMed2001

Design and synthesis of glycolic and mandelic acid derivatives as factor Xa inhibitors.

A series of glycolic and mandelic acid derivatives was synthesized and investigated for their factor Xa inhibitory activity. These analogues are highly potent and selective inhibitors against fXa. In a rabbit deep vein thrombosis model, compound 26 showed significant antithrombotic effects (81% inhibition of thrombus formation) at 1.1 microM plasma concentration following intravenous administration.

Acetanilides↗
PubMed2001

A membrane protein enriched in endoplasmic reticulum exit sites interacts with COPII.

Although all mammalian COPII components have now been cloned, little is known of their interactions with other regulatory proteins involved in exit from the endoplasmic reticulum (ER). We report here that a mammalian protein (Yip1A) that is about 31% identical to S. cerevisiae and which interacts with and modulates COPII-mediated ER-Golgi transport. Yip1A transcripts are ubiquitously expressed. Transcripts of a related mammalian homologue, Yip1B, are found specifically in the heart. Indirect immunofluorescence microscopy revealed that Yip1A is localized to vesicular structures that are concentrated at the perinuclear region. The structures marked by Yip1A co-localized with Sec31A and Sec13, components of the COPII coat protein complex. Immunoelectron microscopy also showed that Yip1A co-localizes with Sec13 at ER exit sites. Overexpression of the hydrophilic N terminus of Yip1A arrests ER-Golgi transport of the vesicular stomatitis G protein and causes fragmentation and dispersion of the Golgi apparatus. A glutathione S-transferase fusion protein with the hydrophilic N terminus of Yip1A (GST-Yip1A) is able to bind to and deplete vital components from rat liver cytosol that is essential for in vitro vesicular stomatitis G transport. Peptide sequence analysis of cytosolic proteins that are specifically bound to GST-Yip1A revealed, among other proteins, mammalian COPII components Sec23 and Sec24. A highly conserved domain at the N terminus of Yip1A is required for Sec23/Sec24 interaction. Our results suggest that Yip1A is involved in the regulation of ER-Golgi traffic at the level of ER exit sites.

Amino Acid Sequence↗
PubMed2001

Downregulation of K(+) channel genes expression in type I diabetic cardiomyopathy.

Type I diabetic cardiomyopathy has consistently been shown to be associated with decrease of repolarising K(+) currents, but the mechanisms responsible for the decrease are not well defined. We investigated the streptozotocin (STZ) rat model of type I diabetes. We utilized RNase protection assay and Western blot analysis to investigate the message expression and protein density of key cardiac K(+) channel genes in the diabetic rat left ventricular (LV) myocytes. Our results show that message and protein density of Kv2.1, Kv4.2, and Kv4.3 are significantly decreased as early as 14 days following induction of type I diabetes in the rat. The results demonstrate, for the first time, that insulin-deficient type I diabetes is associated with early downregulation of the expression of key cardiac K(+) channel genes that could account for the depression of cardiac K(+) currents, I(to-f) and I(to-s). These represent the main electrophysiological abnormality in diabetic cardiomyopathy and is known to enhance the arrhythmogenecity of the diabetic heart. The findings also extend the extensive list of gene expression regulation by insulin.

Animals↗
PubMed2001

p15(PAF), a novel PCNA associated factor with increased expression in tumor tissues.

Proliferating cell nuclear antigen (PCNA) is an essential protein in both DNA replication and DNA damage repair. A novel 15 kD protein, p15(PAF), was identified as a PCNA-associated factor in a yeast two-hybrid screen using PCNA as the bait. p15(PAF) is localized primarily in the nucleus. p15(PAF) shares the conserved PCNA binding motif with several other PCNA binding proteins including CDK inhibitor p21. Overexpression of p15(PAF) competes with p21-PCNA binding. Mutation of this motif in p15(PAF) abolished its PCNA-binding activity. Notably, p15(PAF) expression in several types of tumor tissues was significantly increased, especially in esophageal tumors. Like PCNA, p15(PAF) may possess prognostic significance in a broad array of human cancers.

Amino Acid Sequence↗
PubMed2001

Construction and expression of eukaryotic expressing vector pCH510 of polypeptide CH50 and its chemotaxis and antitumor function by in vivo transfection.

To construct an eukaryotic expressing vector that expresses CH50, a recombinant Cell I-Hep II bifunctional-domain polypeptide of human fibronectin, and to investigate the chemotaxis to immune cells and the inhibitory effect on the growth of tumor by the expression of the plasmid in vivo, the plasmid was constructed by DNA recombination. Gene transfection was performed in vitro and in vivo. The expressed product was identified by Western blot. The chemotaxis after gene transfection in vivo was observed by histotomy and staining of muscle tissues. The inhibition of gene transfection on solid tumor was observed in mice. The results showed that plasmid pCH510 was constructed by the recombination of the 5'-terminal noncoding region and signal peptide coding region of human fibronectin cDNA and cDNA fragment coding CH50 polypeptide with a 3'-terminal noncoding region of human FN cDNA, and the insertion of the recombinated fragment into plasmid pcDNA3. 1. After transfection with plasmid pCH510, NIH3T3 cells could produce CH50 polypeptide. The transfection of plasmid pCH510 by the injection in muscle of mouse could produce the effects of chemotaxis on immune cells and the inhibition on the growth of solid tumor. It is concluded that plasmid pCH510 can express in cells and in vivo in mouse. The expression of the plasmid in vivo has a chemotactic effect on immune cells and can inhibit the growth of solid tumor.

3T3 Cells↗
PubMed2001

Speciation of rare earth elements in soil by sequential extraction then HPLC coupled with visible and ICP-MS detection.

The distribution of rare earth elements (REE) in a pooled soil sample collected from Zhangzhou, Fujian Province, China, was screened by a five-step sequential extraction procedure coupled with ICP-MS determination after preconcentration of REE and removal of the matrix by extraction with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP). The results showed that the distribution of REE in the different fractions of the pooled soil sample studied followed the order soluble species (46.76%) > species bound to organic matter (22.08%) > species in the residue (16.77%) > species bound to Fe-Mn oxides (2.02%). An effective method for speciation of REE, which utilized weak cation-exchange HPLC separation hyphenated with post-column derivatization and visible or on line ICP-MS detection, was, moreover, developed and successfully applied to the speciation of REE in the soluble extract of the pooled soil sample. The stability of known complexes of lanthanum during the HPLC separation was investigated with fluoride, citrate, and ethylenediamine tetraacetic acid (EDTA) chosen as ligands modeling those in the soil. REE in the soluble extract of the pooled soil sample were subsequently classified into three types of species--< or = +1 charged complexes (negatively charged, neutral, and +1 charged), +2 charged complexes, and "free" REE species. This method is expected to be useful for identification of bioavailable (or toxic) species of REE in environmental samples.

Journal Article↗
PubMed2001

Spatial alterations of Kv channels expression and K(+) currents in post-MI remodeled rat heart.

OBJECTIVE: The hypothesis being tested in the present study is that increased anisotropic properties occurs in the remodeled post-infarction heart due to spatial alterations in Kv channels expression and K(+) currents of the remodeled myocardium. METHODS: Three to 4 weeks post myocardial infarction (MI) in the rat, we measured the two components of the outward K(+) current, I(to-fast (f)) and I(to-slow(s)) in the epicardium (epi) and endocardium (endo) of noninfarcted remodeled left ventricle (LV) using patch clamp techniques. Alterations in mRNA and/or protein levels of potassium channel genes Kv1.4, Kv1.5, Kv2.1, Kv4.2 and Kv4.3 were measured in epi, midmyocardium (mid), and endo regions of LV and in the right ventricle (RV). RESULTS: In sham operated rat heart, the density of I(to-f) was 2.3 times greater in epi compared to endo myocytes. In post-MI heart, the density of I(to-f) and I(to-s) decreased to a similar degree in LV epi and endo but the difference in I(to-f) density between epi and endo persisted. The mRNA and/or protein levels of Kv1.4, Kv2.1, Kv4.2 and Kv4.3 but not Kv1.5 decreased to a varying extent in different regions of LV but not in RV of post-MI heart. CONCLUSIONS: Our results suggest that regional downregulation of Kv channels expression and density of K(+) currents can be a significant determinant of increased spatial electrophysiological heterogeneity and contribute to increased electrical instability of the post-MI heart.

Analysis of Variance↗
PubMed2001

Involvement of antioxidants and lipid peroxidation in the adaptation of two cool-season grasses to localized drought stress.

In natural environments, drought often occurs in surface soil while water is available for plant uptake deeper in the soil profile. The objective of the study was to examine the involvement of antioxidant metabolism and lipid peroxidation in the responses of two cool-season grasses to surface soil drying. Kentucky bluegrass (Poa pratensis L) and tall fescue (Festuca arundinacea Schreb.) were grown in split tubes, consisting of two sections (each 10 cm in diameter and 20 cm long). Grasses were subjected to three soil moisture regimes: (a) well-watered control: whole soil profile was watered; (b) surface drying: surface 20 cm of soil was dried by withholding irrigation and the lower 20 cm of soil was watered; (c) full drying: whole soil profile was dried. Surface drying had no effects on relative water content (RWC) and chlorophyll content (Chl) for both grasses and only slightly reduced shoot growth for tall fescue. Superoxide dismutase (SOD) activity increased, while catalase (CAT) and peroxidase (POD) activities remained unchanged during most periods of surface drying. Malondialdehyde (MDA) content was unaffected by surface drying for tall fescue, but increased initially and then decreased to the control level for Kentucky bluegrass. Under full drying, RWC, Chl content, and shoot dry weight decreased, but MDA content increased in both grasses; SOD and POD activities initially increased transiently and then decreased; CAT remained unchanged for 25 days and then decreased. These results suggested that both Kentucky bluegrass and tall fescue were capable of surviving surface soil drying. This capability could be related to increases in antioxidant activities, particularly SOD and CAT. However, full drying suppressed antioxidant activities and induced lipid peroxidation.

Journal Article↗
PubMed2001

Regulation of plant water loss by manipulating the expression of phospholipase Dalpha.

Phospholipase D (PLD) has been implicated in various processes, including signal transduction, membrane trafficking, and membrane degradation. Multiple forms of PLD with distinct biochemical properties have been described in the cell. In Arabidopsis, PLDalpha and PLDgamma, but not PLDbeta, were detected in guard cells, and antisense suppression resulted in a specific loss of PLDalpha. The abrogation of PLDalpha rendered plants less sensitive to abscisic acid and impaired stomatal closure induced by water deficits. PLDalpha-depleted plants exhibited accelerated transpirational water loss and a decreased ability to tolerate drought stress. Overexpression of PLDalpha enhanced the leaf's sensitivity to abscisic acid. These findings provide molecular and physiological evidence that PLDalpha plays a crucial role in regulating stomatal movement and plant-water status.

Abscisic Acid↗