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C Huang

Publications and source records attributed to C Huang.

At least 361 records · Page 20Linked to original sources
PubMed1996

Ser-268 plays an important role in ligand binding of prostaglandin E2 receptor EP3alpha subtype.

Functional mouse prostaglandin E2 (PGE2) receptor EP3alpha subtype has been expressed in insect cells using the baculovirus system (C. Huang and H. H. Tai, 1995,Biochem . J. 307, 493-498). Site directed mutagenesis was carried out at Thr-221, Ser-268, and Ser-272. These hydroxy amino acid residues are highly conserved among prostaglandin receptors of many species and could potentially form hydrogen bonds with the hydroxyl group or the keto group of the receptor ligand PGE2. The mutant EP3alpha receptors again were expressed in insect cells and were studied by [3h]PGE2 binding assay. The results indicated that (1) replacement of Ser-272 by alanine did not cause any significant change in PGE2-binding activity, (2) replacement of Thr-221 by alanine also did not cause any significant change in PGE2-binding activity, and (3) replacement of Ser-268 by alanine almost abolished the PGE2-binding activity, while replacement by a threonine did not cause significant change in the PGE2-binding activity but did alter subtype specificity. These results suggest that Ser-268 of EP3alpha receptor plays an important role in ligand binding.

Amino Acid Sequence↗
PubMed1996

Hantavirus S RNA sequence from a fatal case of HPS in New York.

In April, 1995, the second fatal case of hantavirus pulmonary syndrome (HPS) occurred in the northeast in a New York State resident. Using the patient's lung tissue obtained at autopsy, the S genomic RNA segment of a hantavirus, designated H-NY1, was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR), cloned, and sequenced. The S RNA was found to contain 2084 nucleotides, 6 nucleotides longer than reported by Hjelle et al. (1995) for the virus associated with the first northeastern case (RI-1). There were 101 nucleotide differences in the S RNA between the H-NY1 and RI-1, which result in the prediction of a single amino-acid change in the nucleocapsid (N) protein. Rodents were trapped for serologic and virologic studies at the patient's residence and work site. The white-footed mouse (Peromyscus leucopus) was the most frequently captured species and more than 50% of those trapped near the patient's residence showed serologic evidence of hantavirus infection. Using RT-PCR it was possible to amplify hantavirus S RNA sequence from the lung tissues of 8 out of 11 seropositive animals. No difference in nucleotide sequence was found between the HPS patient sequence and the P. leucopus sequence (nucleotides 189 to 599). These data are consistent with those of Hjelle et al. (1995) in suggesting that P. leucopus is the primary rodent vector for the etiologic agent of HPS in the northeastern United States.

Adult↗
PubMed1996

Contributions of vertebral fractures to stature loss among elderly Japanese-American women in Hawaii.

Loss of stature is a typical feature of osteoporosis and associated vertebral fractures. However, there have been few prospective population-based studies to estimate the magnitude of this association. Further, the separate contributions of different types of vertebral fractures to stature loss have not been evaluated using prospective data. In this study we investigated the extent to which stature loss could be explained by the number of different types of vertebral fractures (wedge, endplate, and crush fractures) after adjusting for other covariates. Longitudinal data on stature loss and vertebral fractures were collected among 504 postmenopausal Japanese-American women living in Hawaii with mean age 73.4 (SD 4.9) years. During an average of 7.7 years of follow-up, women with at least one incident vertebral fracture had an average of 2.1 cm of stature loss while the average stature loss among those without incident fractures was only 0.4 cm. The mean rate of stature loss was very slight (< 1 mm/year) for those without incident vertebral fractures even after age 80. Our analyses suggest that both the number of wedge and the number of crush fractures are strong predictors of stature loss. After adjusting for age and total height loss in the anterior dimension over T3-L5, the estimated stature loss resulting from each wedge and crush fracture was 0.86 and 1.08 cm, respectively. Endplate fractures did not show significant contributions to stature loss.

Adult↗
PubMed1996

Vertebral fractures and other predictors of back pain among older women.

We examined the prevalence and predictors of back pain (BKP) among 645 postmenopausal Japanese-American women in Hawaii with a mean age of 73.9 years (ranging from 55 to 93 years) and serial spine radiographs during the preceding 12 years. The overall prevalence of BKP was 32.9% and appeared to be constant up to age 80, with an increase thereafter. At most ages, pain in the lower back was the most common, upper BKP was less so, and mid-BKP was the least common. The overall prevalence of BKP among Japanese-American women in Hawaii was about half of that reported for U.S. Caucasians. Vertebral fractures were divided into three categories based on the length of time since the fracture was identified on radiographs. BKP was only associated with recent vertebral fractures (during the previous 4 years, on average) and increased progressively with the number and severity of fractured vertebrae. A history of a single recent fracture was associated with a 2.8-fold increase in the odds of BKP; two recent fractures with a 7.8-fold increase and three recent fractures with a 21.7-fold increase in the odds of BKP. In addition, self-reported disk problems, body mass index, and the number of other painful joints also showed independent associations with BKP. Height, spine bone mineral density (BMD), calcaneus BMD, smoking, and number of live births were not significantly associated with BKP.

Age Distribution↗
PubMed1996

Blinded reading of radiographs increases the frequency of errors in vertebral fracture detection.

We examined the effect of blinding X-rays to film sequence and patient identity on vertebral fracture detection. A sample of 50 postmenopausal women with low bone density and two sets of spine X-rays 3.6 years apart was selected; based on prior morphometric studies, about half of the women had experienced new fractures after the initial film. New morphometric and semiquantitative radiologist readings were each performed twice: blinded and unblinded. For morphometry, incident fractures were defined as vertebral height decreases of more than 15% compared with the initial film. The incidence was slightly higher when blinded versus unblinded (5.6 vs. 5.3% of all vertebrae for morphometry, and 9.7 vs. 8.7% for the radiologist), but these differences were not significant. The error rate was investigated by examining the frequency of "fracture reversals"-vertebrae identified as fractured on the initial film but not on the later film. Agreement between blinded and unblinded readings was generally greater than 80% for fractures but less than 10% for "fracture reversals," suggesting that reversals are not true events but random errors. The number of reversals was higher when the radiologist was blinded (2.1% of all vertebrae vs. 0.8% when unblinded; p = 0.07). The number of vertebrae with increases greater than 15% in size over time was also greater when morphometry readings were blinded versus unblinded: 0.8 versus 0% (p < 0.05). Although these errors are small, they are similar in magnitude to the annual fracture incidence in many populations. These data show that blinding X-rays to sequence offers no advantages, increases the frequency of errors, and may inflate incidence rates. We conclude that the assessment of X-rays for vertebral fractures in clinical trials should not be performed with the evaluator blinded to the sequence of the X-rays.

Diagnostic Errors↗
PubMed1996

Comparison of bone densitometry of the phalanges, distal forearm and axial skeleton in early postmenopausal women participating in the EPIC Study.

We present baseline bone densitometry from the Early Postmenopausal Interventional Cohort study (EPIC, sponsored by Merck, Sharp & Dohme) for the first time, in which 1609 women from England, Oregon, Hawaii and Denmark are participating to investigate the efficacy of daily oral alendronate to prevent early postmenopausal bone loss. We compared radiographic absorptiometry (RA) of the phalanges for bone mineral density (BMD) measurement with single-energy X-ray absorptiometry (SXA) of the distal forearm, and dual-energy X-ray absorptiometry (DXA) of the lumbar spine, proximal femur and distal forearm. In a random subgroup of 308 women, aged 45-60 years, on average 6 years since menopause (YSM), bone densitometry was measured once at baseline by RA of the phalanges besides the mandatory measurements by DXA. Bone densitometry was furthermore measured by SXA at the Danish site (89 women). Sixty-eight of the women had duplicate measurements performed within 1-3 weeks to evaluate the short-term precision error (CV%). One hundred and one healthy premenopausal women, aged 25-48 years, were recruited at the Danish and Hawaiian sites to establish a reference group. The precision error was 1.5% for RA of the phalanges and in the range 1.0-2.2% for SXA and DXA. BMD by RA correlated with BMD measured by SXA and DXA in the range 0.45 < r < 0.72 (p < 0.001). In conclusion, bone densitometry by RA of the phalanges is highly correlated with bone densitometry by SXA and DXA. RA of the phalanges has a short-term precision error comparable to that of SXA and DXA.

Absorptiometry, Photon↗
PubMed1996

Determinants of vertebral fracture prevalence among native Japanese women and women of Japanese descent living in Hawaii.

Age-adjusted prevalence of vertebral fracture has been reported to be higher among native Japanese women than among women of Japanese descent living in Hawaii. In this cross-sectional population-based study, we examined a variety of potential risk factors for associations with prevalent vertebral fractures and investigated whether these factors could explain the difference in vertebral fracture prevalence between native Japanese and Japanese-American women. Spine radiographs and data on spine bone mineral density (BMD) and other potential risk factors were collected among 802 Japanese women aged 50-88 years living in Hiroshima and 840 Japanese-American women aged 52-88 years living in Hawaii. In logistic regression analysis, BMD was a major predictor of prevalent vertebral fracture. In linear regression models, weight, age, and menstrual history (age at menopause or years between menarche and menopause) were significantly associated with BMD and thus might contribute to fracture risk indirectly through their effects on BMD. However, age and menstrual history provided additional and complementary information about fracture prevalence after adjusting for BMD. These variables together explained much of the difference in vertebral fracture prevalence between the two study populations. We conclude that the observed difference in age-adjusted prevalence of spine fracture between native Japanese and Japanese-American women was accounted for primarily by the differences in BMD, duration of estrogen exposure, and/or duration of estrogen deficiency. Thus, current BMD is a major but not the sole risk factor for vertebral fractures. Age-related and menopause-related mechanisms may also play an important role in spine fracture independent of BMD.

Absorptiometry, Photon↗
PubMed1996

Effects of alcohols on the phase transition temperatures of mixed-chain phosphatidylcholines.

The biphasic effect of ethanol on the main phase transition temperature (Tm) of identical-chain phosphatidyl-cholines (PCs) in excess H2O is now well known. This biphasic effect can be attributed to the transformation of the lipid bilayer, induced by high concentrations of ethanol, from the partially interdigitated L beta, phase to the fully interdigitated L beta I phase at T < Tm. The basic packing unit of the L beta I phase has been identified recently as a binary mixture of PC/ethanol at the molar ratio of 1:2. The ethanol effect on mixed-chain PCs, however, is not known. We have thus in this study investigated the alcohol effects on the Tm of mixed-chain PCs with different delta C values, where delta C is the effective acyl chain length difference between the sn-1 and sn-2 acyl chains. Initially, molecular mechanics (MM) simulations are employed to calculate the steric energies associated with a homologous series of mixed-chain PCs packed in the partially and the fully interdigitated L beta I motifs. Based on the energetics, the preference of each mixed-chain PC for packing between these two different motifs can be estimated. Guided by MM results, high-resolution differential scanning calorimetry is subsequently employed to determine the Tm values for aqueous lipid dispersions prepared individually from a series of mixed-chain PCs (delta C = 0.5-6.5 C-C bond lengths) in the presence of various concentrations of ethanol. Results indicate that aqueous dispersions prepared from mixed-chain PCs with a delta C value of less than 4 exhibit a biphasic profile in the plot of Tm versus ethanol concentration. In contrast, highly asymmetric PCs (delta C > 4) do not exhibit such biphasic behavior. In the presence of a longer chain n-alcohol, however, aqueous dispersions of highly asymmetric C(12):C(20)PC (delta C = 6.5) do show such biphasic behavior against ethanol. Our results suggest that the delta C region in a highly asymmetric PC packed in the L beta I phase is most likely the binding site for n-alcohol.

Alcohols↗
PubMed1996

Establishment of monoclonal antibodies against human erythrocyte NADH-cytochrome b5 reductase.

NADH-cytochrome b5 reductase (b5R) is a multifunctional redox enzyme, whose deficiency leads to hereditary methemoglobinemia. By using recombinant human red cell b5R as antigen to immunize BALB/c mice and conventional cell fusion, we have established two mouse hybridoma cell lines secreting IgG monoclonal antibodies (MAbs) to b5R. In immunoblotting, the MAbs were shown to react specifically with b5R. They were also found to be capable of capturing b5R activity from b5R solution and normal human hemolysate. It was implied that the binding sites of the MAbs might not be proximal to the active site of the enzyme, but might be in close proximity to each other. The MAbs will be useful in b5R-related investigations.

Antibodies, Monoclonal↗
PubMed1996

Mapping the neutralizing epitopes on the glycoprotein of infectious haematopoietic necrosis virus, a fish rhabdovirus.

Twelve neutralizing monoclonal antibodies (MAbs) against the fish rhabdovirus, infectious haematopoietic necrosis virus (IHNV), were used to select 20 MAb escape mutants. The nucleotide sequence of the entire glycoprotein (G) gene was determined for six mutants representing differing cross-neutralization patterns and each had a single nucleotide change leading to a single amino acid substitution within one of three regions of the protein. These data were used to design nested PCR primers to amplify portions of the G gene of the 14 remaining mutants. When the PCR products from these mutants were sequenced, they also had single nucleotide substitutions coding for amino acid substitutions at the same, or nearby, locations. Of the 20 mutants for which all or part of the glycoprotein gene was sequenced, two MAbs selected mutants with substitutions at amino acids 230-231 (antigenic site I) and the remaining MAbs selected mutants with substitutions at amino acids 272-276 (antigenic site II). Two MAbs that selected mutants mapping to amino acids 272-276, selected other mutants that mapped to amino acids 78-81, raising the possibility that this portion of the N terminus of the protein was part of a discontinuous epitope defining antigenic site II. CLUSTAL alignment of the glycoproteins of rabies virus, vesicular stomatitis virus and IHNV revealed similarities in the location of the neutralizing epitopes and a high degree of conservation among cysteine residues, indicating that the glycoproteins of three different genera of animal rhabdoviruses may share a similar three-dimensional structure in spite of extensive sequence divergence.

Amino Acid Sequence↗
PubMed1996

The S RNA genomic sequences of Inkoo, San Angelo, Serra do Navio, South River and Tahyna bunyaviruses.

The complete nucleotide sequences of the small (S) genomic RNA segments of five California (CAL) serogroup bunyaviruses (two Inkoo virus strains, San Angelo virus, Serra do Navio virus, South River virus and Tahyna virus) were determined. In agreement with previously published data concerning CAL serogroup viruses, the nucleocapsid (N) and non-structural (NSs) proteins were encoded in over-lapping open reading frames (ORFs). All N protein ORFs were 708 nucleotides in length and encoded a 235 amino-acid gene product. The NSs ORFs were either 279 or 294 nucleotides in length, which would encode 92 or 97 amino-acid proteins, respectively. Comparative analysis of the nucleotide sequences and amino acids corresponding to the nucleocapsid protein resulted in a predicted relationship among these viruses that generally agreed with those determined by serology. The only exception was Inkoo virus, where comparisons based on the S RNA sequence and partial M RNA sequence suggest that this virus is more similar to Jamestown Canyon virus of the Melao complex than it is to viruses such as Tahyna and La Crosse viruses of the California encephalitis complex.

Amino Acid Sequence↗
PubMed1996

Requirement for phosphatidylinositol 3-kinase in epidermal growth factor-induced AP-1 transactivation and transformation in JB6 P+ cells.

Phosphatidylinositol 3-kinase (PI 3-kinase) plays a role in a variety of biological processes, including regulation of gene expression, cell growth, and differentiation. However, little is known about its role in the cytoplasmic events involved in epidermal growth factor (EGF)-induced transduction of signals to the transcriptional machinery of the nucleus and in EGF-induced cell transformation. In this study, we examined whether PI 3-kinase is a mediator for the activation of AP-1 and neoplastic transformation by EGF in the murine epidermal cell line JB6. The results showed the following. (i) EGF not only induced a high level of PI 3-kinase activity by itself but also enhanced insulin-induced PI 3-kinase activity in JB6 P+ cells, the EGF-induced PI-3 kinase activity could be blocked by constitutive overexpression of a dominant negative P85 subunit of PI 3-kinase (deltaP85), and insulin could markedly promote EGF-induced AP-1 activity in a dose-dependent manner in JB6 P+ cells as well as promote EGF-induced JB6 P+ cell transformation. (ii) Inhibition of PI-3 kinase with wortmannin or LY294002 markedly decreased the AP-1 activity induced by insulin, EGF, or EGF and insulin in a dose-dependent manner, while wortmannin did not block UVB-induced AP-1 activity. (iii) AP-1 activation by insulin, EGF, or EGF and insulin could be completely inhibited by overexpression of deltaP85 in all the dose and time courses studied. (iv) Inhibitors of PI 3-kinase (wortmannin and LY294002) and stable overexpression of deltaP85 inhibited EGF-induced transformation but had no significant inhibitory effect on cell proliferation induced by EGF or EGF and insulin. These results demonstrate for the first time that PI 3-kinase appears to be required for EGF- or insulin-induced AP-1 transactivation and cell transformation but not cell proliferation in JB6 cells.

Androstadienes↗
PubMed1996

[Study on the stability of Japanese encephalitis vaccine--development of freeze-dry dosage form].

In order to prolong shelf-life and improve the quality of the vaccine product, not only an effective stabilizer but also a more proper dosage form has been sought. The stability of a Japanese encephalitis (JE) vaccine produced from mouse brain along with a variety of stabilizers and lyophilization protocols was evaluated. Without any stabilizers added, almost 90% of the antigenicity would vanish after freeze-drying process. Comparative studies of various compounds, including carbohydrates, amino acids, peptides and medium 199, on both antigenicity preservation and thermostability of the vaccine were carried out. The results indicated that the best reconstituted vaccines were prepared with two stabilizer formulations, sucrose and sucrose/gelatin. They were further examined by accelerated stability test at room and higher temperatures. The sucrose-added lyophilized vaccine can retain its original antigenicity for more than 60 days both at 37 degrees C and 45 degrees C. We conclude the thermostability efficiency of each of the stabilizers tested is as that follows: sucrose > sucrose/gelatin > gelatin/medium > gelatin.

Animals↗
PubMed1996

Adenovirus-mediated in vivo gene transfer in a rabbit model of allograft vasculopathy.

BACKGROUND: The long-term success of heart transplantation continues to be in jeopardy because of the development of accelerated vascular myointimal proliferation. Transfer of genes encoding products that can modulate the adverse consequences of phenomena that cause myointimal proliferation, into the allograft vessel wall, may modify these pathologic processes. The purpose of this study was to assess the feasibility of gene transfer and to evaluate the duration of gene expression in a rabbit heterotopic aortic transplant model of allograft vasculopathy. METHODS: The abdominal aortas of 32 outbred New Zealand rabbits were harvested and cross-sectionally bisected (n = 64). Six donor and recipient animals were used in a preliminary study to examine neointimal proliferation without accompanying gene transfer. Of the remaining 26 rabbits (52 allografts), one half of each allograft aorta was administered a control solution, while the other half was incubated with a replication-defective, recombinant, adenoviral vector-encoding, cytomegalovirus promoter-regulated beta-galactosidase. After a 20-minute incubation period, bilateral aorto-carotid transplantations were performed in 26 recipient rabbits. All animals received cyclosporine immunosuppression (10 mg/kg/day subcutaneously). The allografts were harvested at 3, 7, 10, 21, and 28 days after transplantation and assayed for beta-galactosidase activity. RESULTS: Neointimal areas showed an initially slow increase for the first 10 days, followed by a rapid increase up to 21 days, and tended to plateau thereafter. Significant beta-galactosidase was apparent in aortic sections dissected from host rabbits for all time points, except at 28 days. At the 21-day time point, the aortic section from one rabbit was positive, whereas the other two remained negative. However, the one positive section showed intense beta-galactosidase activity, suggesting variability in the experimental model. At 28 days, all aortic sections were negative. CONCLUSIONS: Our findings confirm that genes delivered by this method are expressed for the duration of early rapid intimal proliferation in this heterotopic rabbit model of aortic allograft vasculopathy. These findings suggest that this animal model can be used to assess the therapeutic potential of gene transfer at the time of vascular transplantation and may provide a novel therapeutic approach to prevent or ameliorate the genesis of allograft vasculopathy.

Adenoviruses, Human↗
PubMed1996

[Expression of S.sonnei form I antigen gene and V.cholerae toxin B subunit gene in S.flexneri 2a strain and investigation of their immunoprotective response in mice].

The genes encoding S. sonnei form I O antigen and V. cholerae B subunit were cloned into an expression vector containing asd gene of Streptococcus mutans by gene recombination. The final recombination plasmid was transformed into the asd mutant of S. flexneri 2a (strain T32). Analysis of LPS silver staining and western blotting indicated that the genes encoding CT-B and form I O antigen could stably express in the asd mutant T32 strain. Immune protection tests in mice showed that the recombinant strain constructed in this study could provide 100% protection against the challenge from S. flexneri 2a and S. Sonnei and also showed a good immune protection (70%) against V. cholerae. This recombinant strain has the following advantages: trivalent, stable and no vector drug resistance markers.

Animals↗
PubMed1996

Construction of a stable and non-resistant bivalent vaccine candidate strain against Shigella flexneri 2a and Shigella sonnei.

The E. coli cs3 gene coding for CFA/II antigen was site-specifically integrated into the asd gene locus of S. flexneri 2a vaccine strain T32, resulting in the inactivation of the asd gene. Meanwhile, the gene cluster for S. sonnei O antigen was cloned into a non-resistant expression vector pXL378 to construct the plasmid pXL390. By transforming the asd-mutant of the T32 strain with pXL390, the bivalent vaccine candidate strain FS01 against S. flexneri 2a and S. sonnei was finally obtained. Experiments showed that the recombinant plasmid pXL390 was very stable in the asd-T32 strain without the use of any antibiotics; the FS01 strain was genetically stable and expressed two kinds of Shigella LPS-O antigens on the surface without any enhancement of its toxicity. Animal tests demonstrated that FS01 strain, when administered subcutaneously in mice, could provide 100% protection against the intraperitoneal challenges of virulent S. flexneri 2a and S. sonnei.

Animals↗
PubMed1996

[Effect of dihydroetorphini hydrochloride on mice parturition].

OBJECTIVE: To determine the effect of dihydroetorphini hydrochloride (DHE) on parturition of mice. METHODS: 180 pregnant mice were divided equally into 6 groups. DHE was administered intramuscularly (i.m.) to mice group A, B and C at the dose levels of 1, 2 and 4 micrograms/kg respectively. Morphine hydrochloride 200 micrograms/kg (hypodermic) was given to group D and procaine hydrochloride 1000 micrograms/kg i.m. for group E, while for group F as control distilled water was given. Each preparation was given to the pregnant mice 3 times, i.e. 18 hours before the date of confinement, during labor and 2 hours postpartum. RESULTS: No effects on mice parturition were found in group A, B, E, and F. The percentage of cyanosis in newborn mice of group C and D was 13.8% and 22.8% respectively, which was significantly higher than that (7.4%) in group F. CONCLUSION: DHE is safer than morphine and procaine for analgesia during labor, and no adverse effects of DHE at dose levels of 1 microgram/kg and 2 micrograms/kg were observed on mice parturition.

Abdominal Pain↗