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Biomedical subjects

M Yang

Publications and source records attributed to M Yang.

At least 127 records · Page 7Linked to original sources
PubMed2001

[Anaerobic hydrolysis of terramycin crystallizing mother solution].

The terramycin crystallizing mother solution contained high organics and high nitrogen. There were many kinds of bioinhibition in it but not enough electronic donor. Anaerobic hydrolysis of terramycin crystallizing mother solution was completed with up anarobic sludge bed in order to improve the biodegradability of wastewater and electronic donor in it. The variations of pH, COD, NH4+, and SO4(2-) were monitored. The COD removal was in a narrow range between 10% and 16.4% even when the HRT of the reactor was changed from 1.5 h to 6 h. pH increased because of formation of NH3 and reduction of SO4(2-). Most of SO4(2-) was reduced to S2- when the HRT was longer than 2 h. Batch experiments on hydrolyzed wastewater demonstrated that reaction rates of nitrification and denitrification increased by 90.9% and 45.2%, respectively.

Anaerobiosis↗
PubMed2001

[The emulation of aortic valve vibration during early diastole].

A finite element aortic valve model is described. The geometry and material property of the model are more exact than before. The finite element dynamic analysis was used to, emulate the closed valve motion during the early diastole. The results of emulating demonstrate that the closed valve vibrates during early diastole. They also reveal that the increase in stiffness of valve, the augmentation thickness of valve, the decrease in the rate of change of the pressure, and the reduction of the initial pressure may affect the vibration and cause the diminution of the aortic component of the second heart sound.

Aortic Valve↗
PubMed2001

[Treatment of ion-exchange monosodium glutamate wastewater by yeast].

Two strains of yeasts, Candida halophila and Rhodotorula glutinis, were acquired through screening from ion-exchange monosodium glutamate wastewater (IEMGW) which was characterized by its high contents of COD (40,690 mg/L), NH(4+)-N (16,914 mg/L) and SO(4)2- (18,000 mg/L). The mixture of the two species had a good COD removal performance for treating IEMGW in a pH rang of 4-9. The yeast technology was superior to the conventional activated sludge in terms of COD removal and COD decomposition rate, In a dilution rate range of wastewater from 1:1 to 1:9, a COD removal of 84.5% and an average COD decomposition rate of over 1.0 kg/(kg.d) were obtained under an initial pH of 4.

Candida↗
PubMed2001

[Reconstruction of both eyebrows with scalp flaps with the anastomotic branch in occipital region of superficial temporal artery as the pedicle].

OBJECTIVE: To explore the effects of the reconstruction of both eyebrows with scalp flaps with pedicles supplied by superficial temporal arteries. METHODS: The parietal branch of the superficial temporal and its anastomotic branch of occipital artery at temporoparietal region on the same side were designed as the pedicles, with which two scalp flaps on temporoparietal and temporo-occipital regions with reverse directions were employed to restore the eyebrows on both sides. RESULTS: Four patients were treated with this method with satisfactory appearance and survival rate (100%). The reconstructed eyebrows appeared symmetrical and heavy. CONCLUSION: Scalp flaps with the anastomotic branch at occipital region of superficial temporal artery as the pedicle might be a good choice for the reconstruction of lost eyebrows.

Adolescent↗
PubMed2001

[An experimental study on the effects of NGF on the wound healing of deep partial thickness burn in pigs].

OBJECTIVE: To investigate the effects of nerve growth factor (NGF) on wound healing of deep partial thickness burn in pigs. METHODS: Six pigs of about 20 kg each were employed as the model. Twenty -- four deep partial thickness burn wounds (2.5 cm in diameter per wound) were made on the back of each pig by temperature and pressure controller. Six wounds were set to be one group. The wounds were randomly divided into 4 groups, i.e. control group (applied with normal saline, C), three treatment groups with NGF topically applied in doses of 1, 2.5 and 5 microgram/ml, respectively. Histological examination, determination of hydroxyproline, analysis of cellular DNA cycle and wound healing time in every groups were carried out on 3, 5 and 9 postburn days (PBD). RESULTS: The proliferation rate of epithelia was much more active in treatment groups than in control group. Epithelization of the wound in treatment groups was earlier than of that in control group. The hydroxyproline content in treatment groups exhibited an increment after a prior decrement, especially on 5 PBD when the content was much lower in the treatment groups. The analysis of cellular DNA cycle indicated that cell number of S phase in treatment groups was obviously more than that in the control group. Furthermore, the wound healing time in treatment groups was much shorter than that in control group. CONCLUSION: Local application of NGF might promote the wound healing of deep partial thickness burn.

Animals↗
PubMed2001

[Human cytomegalovirus inhibits the proliferation of CFU-MK in vitro].

OBJECTIVE: To investigate the effect of human cytomegalovirus (HCMV) on the proliferation of colony forming unit-megakaryocyte (CFU-MK). METHODS: Semi-solid CFU-MK culture system was used to observe the effect of HCMV AD169 strain on CFU-MK growth of 20 cord blood samples. HCMV DNA and immediate early antigen (IEA) mRNA in CFU-MK were detected by in situ-polymerase chain reaction (IS-PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: HCMV AD169 suppressed the differentiation and proliferation of CFU-MK in vitro significantly. The suppression was in a dose-dependent fashion. HCMV DNA was successfully detected in colony cells from viral infection group, and did the expression of HCMV IEA mRNA. CONCLUSION: HCMV AD169 can directly infect megakaryocyte progenitor and suppress their proliferation and differentiation.

Cell Proliferation↗
PubMed2001

[Study of specific targeting cytotoxicity mediated by anti-CD(3)/anti-CD(20) Diabody].

OBJECTIVE: To study the specific targeting cytotoxicity mediated by an anti-CD(3)/anti-CD(20) diabody. METHODS: The diabody was purified by affinity chromatography and identified by Western blot assay, size exclusion chromatography, FACS and rosetting assay; the effect of the anti-CD(3)/anti-CD(20) diabody mediated lysis of CD(20)-expressing tumor cells was assayed by (51)Cr release assay in vitro and by human B cell tumor nude mice xenograft model in vivo. RESULTS: The anti-CD(3)/anti-CD(20) diabody could bind both Jurkat cells (CD(3)(+)) and Daudi cells (CD(20)(+)) and appeared to be potent in targeting activated peripheral blood mononuclear cell (PBMC) to lyse Daudi cells in vitro. Furthermore, it inhibited tumor growth and prolonged the survival of mice bearing xenografted Raji cells. CONCLUSION: The diabody proved to be a potent agent for targeting peripheral blood lymphocytes to lyse CD(20) antigen expressing tumor cells in vitro and in vivo.

Animals↗
PubMed2001

[Clinical application and evaluation of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis].

OBJECTIVE: To evaluate the clinical application and feasibility of polymerase chain reaction-microwell plate hybridization assay in the detection of Mycobacterium tuberculosis. METHODS: 1130 specimens with strong suspicion for mycobacterium tuberculosis were collected from the hospitals and were detected by fast bacilli stain, culture, PCR-electrophoresis and PCR-microwell plate hybridization respectively. The laboratory results were analyzed in combination with the symptoms and signs of patients and the observations on treatment. Also detected were 100 samples from the clinically evidenced non-tuberculosis patients. RESULTS: In the 100 samples collected from the patients without tuberculosis, the PCR-hybridization method and culture method did not detect Mycobacterium tuberculosis, but the fast bacilli stain method and PCR-electrophoresis method brought out one and two false-positive results respectively. The results of testing the 1030 clinical samples which probably contained Mycobacterium tuberculosis demonstrated that the PCR-hybridization method had the highest positive rate (481/1030) among the four methods, and the positive rates of the other three methods were PCR-electrophoresis (406/1030), culture (365/1030) and fast bacilli stain (256/1030) in proper order. The chi-square test showed that there were significant difference between the PCR-hybridization method and the other three methods respectively (P < 0.0083 or P < 0.0017). CONCLUSION: PCR-Hybridization method is specific, sensitive, accurate and fast in detecting mycobacterium tuberculosis; it is worthy to be used clinically.

Evaluation Studies as Topic↗
PubMed2000

A multilevel model framework for meta-analysis of clinical trials with binary outcomes.

In this paper we explore the potential of multilevel models for meta-analysis of trials with binary outcomes for both summary data, such as log-odds ratios, and individual patient data. Conventional fixed effect and random effects models are put into a multilevel model framework, which provides maximum likelihood or restricted maximum likelihood estimation. To exemplify the methods, we use the results from 22 trials to prevent respiratory tract infections; we also make comparisons with a second example data set comprising fewer trials. Within summary data methods, confidence intervals for the overall treatment effect and for the between-trial variance may be derived from likelihood based methods or a parametric bootstrap as well as from Wald methods; the bootstrap intervals are preferred because they relax the assumptions required by the other two methods. When modelling individual patient data, a bias corrected bootstrap may be used to provide unbiased estimation and correctly located confidence intervals; this method is particularly valuable for the between-trial variance. The trial effects may be modelled as either fixed or random within individual data models, and we discuss the corresponding assumptions and implications. If random trial effects are used, the covariance between these and the random treatment effects should be included; the resulting model is equivalent to a bivariate approach to meta-analysis. Having implemented these techniques, the flexibility of multilevel modelling may be exploited in facilitating extensions to standard meta-analysis methods.

Clinical Trials as Topic↗
PubMed2000

Assessment of GABA concentration in human brain using two-dimensional proton magnetic resonance spectroscopy.

A quantitative method to assess in vivo brain gamma-aminobutyric acid (GABA) levels is proposed using a J-resolved, two-dimensional (2D) magnetic resonance spectroscopy (MRS) technique. Localized, J-resolved 2D MR spectra were obtained from a 12-cm(3) voxel in the occipital lobe of 36 healthy volunteers (18 male and 18 female, age: 25.1+/-4.8 years). Based on phantom measurements, a GABA resonance peak located at 2.94 ppm, 7.45 Hz, in J-resolved 2D MRS overlaps the least with other resonance peaks which arise from N-acetylaspartate, choline, creatine, glutamate and glutamine. Measurements of this resonance peak yield in vivo GABA concentrations of 1.01+/-0.36 micromol/cm(3) for male and 1.16+/-0.43 micromol/cm(3) for female volunteers, without correction for T1 and T2 relaxation effects. These results are in good agreement with previously reported data and suggest that, with further development, 2D MRS may provide a practical means to estimate the concentration of this important neurotransmitter.

Creatine↗
PubMed2000

Effects of guanidine hydrochloride on the proton inventory of proteins: implications on interpretations of protein stability.

The DeltaG degrees (N)(-)(D) value obtained from extrapolation to zero denaturant concentration by the linear extrapolation method (LEM) is commonly interpreted to represent the Gibbs energy difference between native (N) and denatured (D) ensembles at the limit of zero denaturant concentration. For DeltaG degrees (N)(-)(D) to be interpreted solely in terms of N and D, as is common practice, it must be shown to be independent of denaturant concentration. Because DeltaG degrees (N)(-)(D) is often observed to be dependent on the nature of the denaturant, it is necessary to determine the circumstances under which DeltaG degrees (N)(-)(D) can be interpreted as a property solely of the protein. Here, we use proton inventory, a thermodynamic property of both the native and denatured ensembles, to monitor the thermodynamic character of denaturant-dependent aspects of N and D ensembles and the N right arrow over left arrow D transition. Use of a thermodynamic rather than a spectral parameter to monitor denaturation provides insight into the manner in which denaturant affects the meaning of DeltaG degrees (N)(-)(D) and the nature of the N right arrow over left arrow D transition. Three classes of proteins are defined in terms of the thermodynamic behaviors of their N right arrow over left arrow D transition and N and D ensembles. With guanidine hydrochloride as a denaturant, the classification of protein denaturations by these procedures determines when the LEM gives readily interpretable DeltaG degrees (N)(-)(D) values with this denaturant and when it does not.

Chymotrypsin↗
PubMed2000

Expression of a recombinant human RGR opsin in Lentivirus-transduced cultured cells.

PURPOSE: Our goals were to produce a functional recombinant RPE retinal G protein-coupled receptor (RGR) opsin for biochemical studies and to test the efficiency of a lentiviral vector for transgene expression of human RGR. METHODS: A human RGR cDNA was cloned into a replication-defective lentiviral vector, and recombinant hRGR-Lentivirus was prepared for transduction of the ARPE-19, a human retinal pigment epithelium (RPE) cell line, and COS-7 cells. Recombinant RGR expression was detected by Western blot analysis, and functionality of the protein was tested by a [3H]all-trans-retinal binding assay. RESULTS: RGR protein was detected in each cell type after transduction with recombinant virus and was not observed in untreated cells. RGR expression in ARPE-19 cells increased steadily for up to 10 days after transduction and was stable for at least 6 months. The transduced ARPE-19 cells produced approximately 100-fold higher amounts of RGR protein than the transduced COS-7 cells. When cell membranes from the ARPE-19 cells were incubated with [3H]all-trans-retinal, the chromophore bound specifically to the expressed protein. Uptake of [3H]all-trans-retinol into the ARPE-19 cells was followed by specific binding of radiolabeled retinoid to RGR. CONCLUSIONS: Using a Lentivirus-derived gene delivery system, we were able to express high amounts of human RGR protein in the ARPE-19 human RPE cell line. The transduced ARPE-19 cells remain able to process all-trans-retinol, and the expressed protein is capable of binding to the all-trans-retinal chromophore. The Lentivirus-based expression of functional RGR can be used to study RGR in cultured cells and to test in vivo transduction of quiescent RPE cells.

Animals↗
PubMed2000

Visualizing gene expression by whole-body fluorescence imaging.

Transgene expression in intact animals now can be visualized by noninvasive techniques. However, the instruments and protocols developed so far have been formidable and expensive. We describe here a system for rapidly visualizing transgene expression in major organs of intact live mice that is simple, rapid, and eminently affordable. Green fluorescent protein (GFP) is expressed in the cells of brain, liver, pancreas, prostate, and bone, and its fluorescence is encoded in whole-body optical images. For low-magnification images, animals are illuminated atop a fluorescence light box and directly viewed with a thermoelectrically cooled color charge-coupled device camera. Higher-magnification images are made with the camera focused through an epi-fluorescence dissecting microscope. Both nude and normal mice were labeled by directly injecting 8 x 10(10) plaque-forming units/ml of adenoviral GFP in 20-100 microl PBS and 10% glycerol into either the brain, liver, pancreas, prostate, or bone marrow. Within 5-8 h after adenoviral GFP injection, the fluorescence of the expressed GFP in brain and liver became visible, and whole-body images were recorded at video rates. The GFP fluorescence continued to increase for at least 12 h and remained detectable in liver for up to 4 months. The system's rapidity of image acquisition makes it capable of real-time recording. It requires neither exogenous contrast agents, radioactive substrates, nor long processing times. The method requires only that the expressed gene or promoter be fused or operatively linked to GFP. A comparatively modest investment allows the study of the therapeutic and diagnostic potential of suitably tagged genes in relatively opaque organisms.

Adenoviridae↗
PubMed2000

Refinement of the locus for autosomal dominant hereditary gingival fibromatosis (GINGF) to a 3.8-cM region on 2p21.

Hereditary gingival fibromatosis (HGF, MIM 135300; approved gene symbol GINGF) is an oral disease characterized by enlargement of gingiva. Recently, a locus for autosomal dominant HGF has been mapped to an 11-cM region on chromosome 2p21. In the current investigation, we genotyped four Chinese HGF families using polymorphic microsatellite markers on 2p21. The HOMOG test provided evidence for genetic homogeneity, with evidence for linkage in four families (heterogeneity versus homogeneity test HOMOG, chi(2) = 0. 00). A cumulative maximum two-point lod score of 5.04 was produced with marker D2S390 at a recombination frequency of &theta; = 0 in the four linked families. Haplotype analysis localized the hereditary gingival fibromatosis locus within the region defined by D2S352 and D2S2163. This region overlaps by 3.8 cM with the previously reported HGF region. Single-strand conformation polymorphism and sequence analysis of the coding region of cytochrome P450 1B1 (CYP1B1) excluded it as a likely candidate gene.

Aryl Hydrocarbon Hydroxylases↗
PubMed2000

Structure-based design of an osteoclast-selective, nonpeptide src homology 2 inhibitor with in vivo antiresorptive activity.

Targeted disruption of the pp60(src) (Src) gene has implicated this tyrosine kinase in osteoclast-mediated bone resorption and as a therapeutic target for the treatment of osteoporosis and other bone-related diseases. Herein we describe the discovery of a nonpeptide inhibitor (AP22408) of Src that demonstrates in vivo antiresorptive activity. Based on a cocrystal structure of the noncatalytic Src homology 2 (SH2) domain of Src complexed with citrate [in the phosphotyrosine (pTyr) binding pocket], we designed 3',4'-diphosphonophenylalanine (Dpp) as a pTyr mimic. In addition to its design to bind Src SH2, the Dpp moiety exhibits bone-targeting properties that confer osteoclast selectivity, hence minimizing possible undesired effects on other cells that have Src-dependent activities. The chemical structure AP22408 also illustrates a bicyclic template to replace the post-pTyr sequence of cognate Src SH2 phosphopeptides such as Ac-pTyr-Glu-Glu-Ile (1). An x-ray structure of AP22408 complexed with Lck (S164C) SH2 confirmed molecular interactions of both the Dpp and bicyclic template of AP22408 as predicted from molecular modeling. Relative to the cognate phosphopeptide, AP22408 exhibits significantly increased Src SH2 binding affinity (IC(50) = 0.30 microM for AP22408 and 5.5 microM for 1). Furthermore, AP22408 inhibits rabbit osteoclast-mediated resorption of dentine in a cellular assay, exhibits bone-targeting properties based on a hydroxyapatite adsorption assay, and demonstrates in vivo antiresorptive activity in a parathyroid hormone-induced rat model.

Adsorption↗