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Biomedical subjects

S Huang

Publications and source records attributed to S Huang.

At least 253 records · Page 14Linked to original sources
PubMed1999

[Comparison of constituents extracted from prepared Licorice by semi-bionic extraction with those by water extraction].

OBJECTIVE: To study the granulation of prepared licorice. METHOD: Semi-bionic extraction(SBE) and water extraction(WE) were used in the extraction of prepared licorice, and then compared with glycyrrhetinic acid, total flavone and extract with which were taken as the indexes. RESULT: SBE is superior to WE. CONCLUSION: It is better to use SBE in the preparation of oral licorice granules.

Drugs, Chinese Herbal↗
PubMed1999

[Expression of ET-1 and Pr ET-1 mRNA in kidney of early diabetic rats].

The purpose of this study was to explore the role of endothelin 1 (ET-1) and pr ET-1 mRNA in kidney of early diabetic rats. The location and level of ET-1 were determined by immuno-histochemical staining; ET-1 cDNA probe was used for in situ hybridization. The expressions of ET-1 and ET-1 mENA in the kidneys of 24 early diabetic rats were detected by microscopy and Mia-2000 patho-image-analysis system. The results revealed that the ET-1 mRNA and ET-1 were principally distributed in the glomerular endothelial cells, mesangial cells, smooth muscle cells of vessels, epithelial cell lining tubules and collecting ducts, showing no difference in the distribution over kidney, but the expressions of ET-1 and ET-1 mRNA were higher in the renal medulla. The levels of ET-1 and ET-1 mRNA in glomeruli significantly decreased at week 1 and week 2(P < 0.05), but increased at week 4(P < 0.05). However, the levels of ET-1 and ET-1 mRNA continually increased from week 1 to week 4 in the medulla of diabetic rats. These data suggest that ET-1 and ET-1 mRNA may induce the glomerular hyperperfusion and damage the tubulointerstitial of the kidneys in early diabetic rats.

Animals↗
PubMed1999

[Immunoregulation of IL-2 in Trichinella-infected mice].

AIM: To study the immunoregulation of IL-2 in Trichinella-infected mice. METHODS: Mice infected respectively with HL strain and AM strain larvae of Trichinella spiralis were treated i.p. with IL-2 from the second day postinfection for 3 days. Serum IgG antibody levels were determined by ELISA and the infection capacity was determined using reproductive capacity index (RCI). RESULTS: In HL, higher dosage of IL-2 injection induced lower RCI and showed apparent anti-Trichinella effect. In AM, both low and high dose of IL-2 had no measurable effect on RCI, however, high dose of IL-2 reduced the infectivity of newborn larvae. CONCLUSION: IL-2 exhibits apparent suppressive effect on the infectivity of T. spiralis of HL strain.

Animals↗
PubMed1999

Characteristics of indocyanine green angiography in exudative age-related macular degeneration.

OBJECTIVE: To observe the characteristics of indocyanine green angiography (ICGA) in exudative age-related macular degeneration (AMD). METHODS: Thirty-one cases (39 eyes) were diagnosed as exudative AMD by ocular examination, fundus color photography, fundus fluorescein angiography (FFA) and ICGA. Their ages ranged from 50 to 82 years and visual acuities from FC/30 cm to 0.7. We analyzed and compared the characteristics of ICGA and FFA in these patients. RESULTS: Of 26 eyes with occult choroidal neovascularization (CNV) by FFA, 15 (57.7%) had classic CNV by ICGA. Of 4 eyes with serous retinal pigment epithelial detachment (PED) without CNV by FFA, 1 had serous PED with classic CNV by ICGA. The hyperfluorescence of the scar staining was detecfed by ICGA. CONCLUSION: ICGA adds clinically useful information and is an important adjunct in the evaluation, classification, and laser treatment of patients with occult CNV in AMD.

Aged↗
PubMed1999

[A Raman spectral studies of rare-earth (REE) fluoro-carbonate minerals].

The Raman spectra of REE fluoro-carbonate minerals were studies by a type of RIT-30 laser Raman spectrometer. On the basis of Raman spectral properties, REE fluoro-carbonate minerals can be divided into three groups: Ba-REE fluoro-carbonate mineral, Ca-REE fluoro-carbonate mineral and REE fluoro-carbonate mineral. Obviously, a differential kind of mineral is different in the vibration frequency of the Raman spectra. They are as follows: Cordylite v1-1 088, v2-967, v3-1 538, v4-720, 628; Hauheite v1-1 089,v3-1 525, 1 596, v4-720, 649; Cerbaite v1-1 088, v2-911, v3-1 516, v4-718,625; Parisite v1-1 095,1 075, v2-915, v3-1 461, v4-744, 732; Bastnesite v1-1 098, v2-835, v3-1 476, 1 447, v4-732.

English Abstract↗
PubMed1999

[Fluorescence studies on amoxicillin].

The effects of pH, various organic solvents such as acetone, methanol, ethanol, surface-active agent on amoxicillin have been studied in detail. Put in pH=8 buffer solution, amoxicillin has strong fluorescence emission, excitaion wavelength of 277 nm, and emission wavelength of 303 nm. Calibration curve of amoxicillin was linear between 2 x 10(-5) and 2 x 10(-4) mol/L, with a regression coefficient of 0.9996. CTAB can enhance its fluorescence intensity. The results of fluorescence spectra of amoxicillin added with metal ions (Mg2+, Ca2+, Al3+, Ga3+) at pH=12 showed that there are interactions between amoxicillin and metal ions.

Amoxicillin↗
PubMed1999

[Fluorescence study on phenothiazine and its halogenate derivatives].

The fluorescence spectra of 3-bromine-N-ethyl-phenothiazine with various acid degrees and different polarity surfactants in aqueous solutions were studied in detail. The reasons why fluorescence spectra of Br-Pwere very sensitive to environmental polar and acid changes were discussed based on Lewis acid-base theory. Meanwhile the spectrum of Br-P under ultraviolet ray illumination showed that Br-P had kinetic fluorescence. The method is not only simple but also sensitive with low limit of detection. The calibration curves were linear between 1 x 10(-7) and 1 x 10(-4) mol/L, with a regression coefficient of 0.9995 and RSD<2.8%.

English Abstract↗
PubMed1998

Enhanced rotational dynamics of the phosphorylation domain of the Ca-ATPase upon calcium activation.

We have used labeling conditions that permit the specific and covalent attachment of erythrosin isothiocyanate (Er-ITC) to Lys464 within the phosphorylation domain of the Ca-ATPase in skeletal sarcoplasmic reticulum membranes. These labeling conditions do not interfere with high-affinity ATP binding, phosphoenzyme formation, or phosphoenzyme hydrolysis [Huang, S., Negash, S., and Squier, T. C. (1998) Biochemistry 37, 6949-6957]. Thus, we can use frequency-domain phosphorescence spectroscopy to measure the rotational dynamics of the Ca-ATPase stabilized in different enzymatic states corresponding to the absence of bound ligands (E), calcium activation (E x Ca2), the presence of bound nucleotide (E x ATP), and formation of phosphoenzyme (E-P). We resolve three rotational correlation times corresponding to (i) a large-amplitude domain motion of the phosphorylation domain (phi1 approximately 5 +/- 1 micros), (ii) overall protein rotational motion with respect to the membrane normal (phi2 approximately 50 +/- 10 micros), and (iii) the rotational motion of the SR vesicles (phi3 approximately 1.1 +/- 0.4 ms). No differences are observed in the rotational dynamics of E, E x ATP, or E-P, indicating that phosphoenzyme formation or nucleotide binding result in no global structural changes involving the phosphorylation domain. In contrast, calcium activation enhances the amplitude of motion of the phosphorylation domain. These observed calcium-dependent changes in rotational dynamics result from structural changes within a single Ca-ATPase polypeptide chain, since protein-protein interactions do not change upon calcium binding. Thus, calcium binding induces concerted domain motions within a single Ca-ATPase polypeptide chain that may play a critical role in facilitating substrate binding and utilization.

Animals↗
PubMed1998

Levels of p53 in Epstein-Barr virus-infected cells determine cell fate: apoptosis, cell cycle arrest at the G1/S boundary without apoptosis, cell cycle arrest at the G2/M boundary without apoptosis, or unrestricted proliferation.

The marked increases in p53 and p21/WAF1 levels that occur during Epstein-Barr virus (EBV) infection and the generation of immortal B lymphoblastoid cell lines (LCL) do not lead to growth arrest or apoptosis, although increasing wild-type (wt) p53 levels in EBV-infected cells by transfection or DNA damage induce these effects. We hypothesized that the concentration of p53 relative to that of LMP1 determines whether EBV-infected B cells undergo growth arrest and apoptosis. Cell cycle arrest and apoptosis were evaluated in LCL expressing varying p53 levels achieved by treating the cells with increasing concentrations of cisplatin, and we supplemented this approach with experiments in EBV-infected Burkitt's lymphoma (BL) cells transfected with a temperature-sensitive (ts) mutant human p53 and studies in LCL infected with recombinant adenoviruses expressing wt and ts mutant p53. Small increases in p53 and p21/WAF1 led to cell cycle arrest at the G2/M boundary, but not to apoptosis; moderate increases resulted in growth arrest at the G1/S boundary, also without apoptosis; and large increases also induced apoptosis. These results confirm the hypothesis and reveal unanticipated complexities in cell cycle regulation by p53.

Apoptosis↗
PubMed1998

Assembly of the Hv190S totivirus capsid is independent of posttranslational modification of the capsid protein.

The genome of Helminthosporium victoriae 190S totivirus (Hv190SV) consists of two large overlapping open reading frames (ORFs), encoding a capsid protein (CP) and an RNA-dependent RNA polymerase. The capsid of Hv190SV, even though encoded by a single gene, contains three closely related capsid polypeptides: p88, p83, and p78. p88 and p83 are phosphorylated, whereas p78, which is derived from p88 via proteolytic processing at the C terminus, is nonphosphorylated. In this study we expressed the CP ORF in bacteria and determined that a single product comigrating with virion p88 was generated. Evidence from in vivo phosphorylation studies indicated that the bacterially expressed p88 was unmodified, and thus autophosphorylation was ruled out. Enzymatic-dephosphorylation experiments using 32P-labeled p88 as a substrate demonstrated that the phosphorylated and nonphosphorylated forms of p88 could not be differentiated based on their mobilities in SDS gels and suggested that the two forms occur in purified virions. We also showed that the unmodified p88 is competent for assembly into virus-like particles, indicating that neither phosphorylation nor proteolytic processing of CP is required for capsid assembly. Posttranslational modification of CP, however, is proposed to play an important role in the life cycle of Hv190SV, including regulation of transcription/replication and/or packaging/release from virions of the viral (+) strand RNA transcript.

Capsid↗
PubMed1998

Oral cancer risk in relation to sexual history and evidence of human papillomavirus infection.

BACKGROUND: Experimental models and analyses of human tumors suggest that oncogenic, sexually transmittable human papillomaviruses (HPVs) are etiologic factors in the development of oral squamous cell carcinoma (SCC). We conducted a population-based, case-control study to determine whether the risk of this cancer is related to HPV infection and sexual history factors. METHODS: Case subjects (n = 284) were 18-65-year-old residents of three counties in western Washington State who were newly diagnosed with oral SCC from 1990 through 1995. Control subjects (n = 477) similar in age and sex were selected from the general population. Serum samples were tested for HPV type 16 capsid antibodies. Exfoliated oral tissue collected from case and control subjects and tumor tissue from case subjects were tested for HPV DNA. Odds ratios (ORs) were calculated after adjusting for age, sex, cigarette smoking, and alcohol consumption. RESULTS: Among males only, oral SCC risk increased with self-reported decreasing age at first intercourse, increasing number of sex partners, and a history of genital warts. Approximately 26% of the tumors in case subjects contained HPV DNA; 16.5% of the tumors contained HPV type 16 DNA. The prevalence of oncogenic HPV types in exfoliated oral tissue was similar in case and control subjects. The ORs for HPV type 16 capsid seropositivity were 2.3 (95% confidence interval [CI] = 1.6-3.3) for all oral SCCs and 6.8 (95% CI = 3.0-15.2) for oral SCCs containing HPV type 16 DNA. The joint association of cigarette smoking and HPV type 16 capsid seropositivity with oral SCC (OR = 8.5; 95% CI = 5.1-14.4) was stronger than predicted from the sum of individual associations with current smoking (OR = 3.2; 95% CI = 2.0-5.2) and seropositivity (OR = 1.7; 95% CI = 1.1-2.6). CONCLUSIONS: HPV type 16 infection may contribute to the development of a small proportion of oral SCCs in this population, most likely in combination with cigarette smoking.

Adult↗
PubMed1998

Bmk1/Erk5 is required for cell proliferation induced by epidermal growth factor.

Epidermal growth factor (EGF) induces cell proliferation in a variety of cell types by binding to a prototype transmembrane tyrosine kinase receptor. Ligation of this receptor by EGF activates Erk1 and Erk2, members of the mitogen-activated protein (MAP) kinase family, through a Ras-dependent signal transduction pathway. Despite our detailed understanding of these events, the exact mechanism by which EGF causes cells to proliferate is unclear. Big MAP kinase (Bmk1), also known as Erk5, is a member of the MAP kinase family that is activated in cells in response to oxidative stress, hyperosmolarity and treatment with serum. Here we show that EGF is a potent activator of Bmk1. In contrast to Erk1/2, EGF-mediated activation of Bmk1 occurs independently of Ras and requires the MAP-kinase kinase Mek5. Expression of a dominant-negative form of Bmk1 blocks EGF-induced cell proliferation and prevents cells from entering the S phase of the cell cycle. These results demonstrate that Bmk1 is part of a distinct MAP-kinase signalling pathway that is required for EGF-induced cell proliferation and progression through the cell cycle.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1998

Pluripotent tumor cells in benign pituitary adenomas associated with multiple endocrine neoplasia type 1.

Analysis of human tumor cells in vitro enhances the study of numerous neoplastic conditions. However, it has been difficult to establish long-term cultures of adenoma cells, especially those of neuroendocrine origin, because the endocrine cells survive only briefly in culture, and fibroblasts overgrow the culture dish in 1 or 2 weeks. We describe cells isolated from pituitary adenomas in two patients with multiple endocrine neoplasia type 1 in which cells with a mesenchymal phenotype evolved from pituitary tumor cells. It appears that these poorly differentiated cells arose from multipotent adenoma cells. This represents a path of cell differentiation not observed previously in humans and may help explain the diverse nature of the benign tumors in multiple endocrine neoplasia type 1.

Adenoma↗
PubMed1998

[Comparison of genotype and intellectual phenotype in untreated phenylketonuric children].

OBJECTIVE: The main feature of phenylketonuria(PKU) is mental retardation. Although classical PKU is defined as that the hepatic phenylalanine hydroxylase (PAH) activity ranges 0-1% of normal enzyme, the untreated PKU patients show a wide range of intellectual phenotype. This study sought to find the molecular basis of such variation of intellectual phenotype among PKU. METHODS: 45 classical PKU patients included in the research were screened for detecting six mutant alleles which were rather common among Chinese PKU patients, i.e. R243Q, R413P, Y204C, Y356X, W326X and R111X. PCR-ASO and PCR-SSCP techniques were used. The expression of those mutant PAH genes was analysed by methods of site-directed mutagencies. 27 PKU patients whose two mutant alleles were both defined were involved in this study. The IQ of these patients were tested by DDST system. RESULTS: Among 27 patients, 4/27 (15%) were mild retardation, 10/27(37%) were moderate, the severe mental retardation accounted for 12/27(44%). The relationship between genotype and intellectual phenotype in this group was examined. It was found that the intellectual phenotype of 8 patients were compatible with genotype but not well matched in 19 cases. The enzyme activity of Y204C expressed in vitro was 100%, but all 3 patients with Y204C/Y204C were severely mental retarded. Enzyme activities of R413P and Y356X were <3% and 0 respectively in expression analysis, but the patients in this group had mild or moderate mental retardation. CONCLUSION: Intellectual phenotype was not well matched with the genotype in classical PKU patients, so that genotype can not be used to predicte the intellectual phenotype in PKU patients.

Child↗
PubMed1998

[Screening mutations in phenylketonuria by means of nonradioactive reverse dot blot hybridization].

OBJECTIVE: To establish a simple, accurate and rapid method for screening of the mutant genes in phenylketonuria (PKU). METHODS: Four exons harboring the mutations, Y204C (exon6, E6), R243Q(E7), Y356X(E11) and R413P(E12), were amplified by polymerase chain reaction (PCR) with incorporation of biotinylated deoxynucleotide(biotinylated-11-dUTP or biotinylated-14-dCTP). Hybridization between immobilized allele-specific oligonucleotide probes and biotin-labelled amplified DNA was performed and nonradioactively detected by a colorimetric reaction using streptavidin-alkaline phosphatase. RESULTS: The methods of non-radioactive reverse dot blot hybridization were established to screen the mutations. We detected the genotypes of five PKU patients and found that three of them carried R243Q mutation and one of the three also carried Y356X mutation. These results were confirmed by PCR-single strand conformation polymorphism. CONCLUSION: This method is suitable for rapid screening for common mutations in Chinese PKU patients.

Genetic Testing↗
PubMed1998

Climate change record in subsurface temperatures: A global perspective

Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5 degreesC and that the 20th century has been the warmest of the past five centuries. The subsurface temperatures also indicate that Earth's mean surface temperature has increased by about 1.0 degreesC over the past five centuries. The geothermal data offer an independent confirmation of the unusual character of 20th-century climate that has emerged from recent multiproxy studies.

Journal Article↗