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Biomedical subjects

S Y Zhang

Publications and source records attributed to S Y Zhang.

At least 19 recordsLinked to original sources
PubMed2006

Study of the elastic constants in a La0.6Sr0.4MnO3 film by means of laser-generated ultrasonic wave method.

Two dimensional (2D) displacement field of the laser-generated ultrasonic wave is detected in a two-layered structure of La(0.6)Sr(0.4)MnO(3) (LSMO)/MgO system by means of the optical difference detection method. In order to obtain the elastic constants of the La(0.6)Sr(0.4)MnO(3) thin film, the displacement field of the laser-generated ultrasonic wave for the La(0.6)Sr(0.4)MnO(3)/MgO system is analyzed with finite element method (FEM). We further compare the theoretical simulations with the experimental results, and the elastic constants for the LSMO film, i.e., the Young's modulus and Poisson ratio, are obtained.

Journal Article↗
PubMed2006

Polarized proton collisions at 205 GeV at RHIC.

The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were first accelerated to the record energy of 205 GeV in RHIC with a significant polarization measured at top energy in 2005. This Letter presents the results and discusses the sensitivity of the polarization survival to orbit distortions.

Journal Article↗
PubMed2006

Effects of recombinant human growth hormone on acute lung injury in endotoxemic rats.

OBJECTIVE: To investigate the effects of recombinant human growth hormone (rhGH) on rat acute lung injury (ALI). METHODS: ALI was mimicked by intraperitoneal (i. p.) injection of E. coli. Female Sprague-Dawley rats were randomized into three groups: control group, injected with physiologic saline (i. p.); ALI group, received a bolus injection of E. coli (1 x 10(10) cfu/l, 15 ml/kg, i. p.) followed by intramuscular physiologic saline injection; and ALI + GH group, received a bolus administration of E. coli, and then treated with intramuscular rhGH injection (2.25 U/kg/d). ALI group and ALI + GH group were subdivided into day 1 and day 3 subgroups, respectively. Left lungs were lavaged and bronchial alveolar lavage fluid (BALF) was harvested. Lung injury score, lung wet-to-dry weight (W/D) ratio, percentage of neutrophils (PMNs) in BALF, lung permeability index (LPI), intercellular adhesion molecule-1(ICAM-1) expression and activation of nuclear factor-kappa B (NF-kappaB) in the lungs were determined. RESULTS: (1) On day 1 and day 3, the lung injury score, lung W/D ratio, LPI and protein content in BALF were significantly higher in the ALI group than in the control and ALI + GH groups. rhGH attenuated lung injuries significantly. (2) Compared with the control group, the percentage of PMNs in BALF was elevated significantly in the ALI and ALI + GH groups, especially in ALI group. (3) Nuclear positive rate of NF-kappaB and ICAM-1 expression at the levels of protein and mRNA in the lung in the ALI group on day 1 and day 3 were higher than in the control group. rhGH diminished activation of NF-kappaB and expression of ICAM-1 in the lung markedly. CONCLUSIONS: Treatment with rhGH can significantly attenuate lung injury in the endotoxemic rats, which may be attributed to the reduction of the expression of ICAM-1, the influence on the adhesion and activation of PMNs, the inhibition of the activation of NF-kappaB and the regulation of the transcription of certain proinflammatory cytokines.

Animals↗
PubMed2006

Prevalence and genetic diversity of coronaviruses in bats from China.

Coronaviruses can infect a variety of animals including poultry, livestock, and humans and are currently classified into three groups. The interspecies transmissions of coronaviruses between different hosts form a complex ecosystem of which little is known. The outbreak of severe acute respiratory syndrome (SARS) and the recent identification of new coronaviruses have highlighted the necessity for further investigation of coronavirus ecology, in particular the role of bats and other wild animals. In this study, we sampled bat populations in 15 provinces of China and reveal that approximately 6.5% of the bats, from diverse species distributed throughout the region, harbor coronaviruses. Full genomes of four coronavirues from bats were sequenced and analyzed. Phylogenetic analyses of the spike, envelope, membrane, and nucleoprotein structural proteins and the two conserved replicase domains, putative RNA-dependent RNA polymerase and RNA helicase, revealed that bat coronaviruses cluster in three different groups: group 1, another group that includes all SARS and SARS-like coronaviruses (putative group 4), and an independent bat coronavirus group (putative group 5). Further genetic analyses showed that different species of bats maintain coronaviruses from different groups and that a single bat species from different geographic locations supports similar coronaviruses. Thus, the findings of this study suggest that bats may play an integral role in the ecology and evolution of coronaviruses.

Animals↗
PubMed2005

Magnetic resonance arthrography applied to the diagnosis of intraarticular adhesions of the temporomandibular joint.

The purpose of this study is to investigate the diagnostic accuracy of magnetic resonance arthrography (MRAr) on the diagnosis of intraarticular adhesions of the temporomandibular joint (TMJ). Twenty-four patients (31 joints) diagnosed as internal disorders of TMJ were examined to establish the presence, suspicion or absence of intraarticular adhesions through MRAr according to the MRAr radiographic criteria in a blind fashion, subsequent arthroscopy were performed on all 31 joints. The findings were compared to MRAr with those of arthroscopy. The comparison data were assessed by generating receiver operating characteristic curve (ROC curve) and analyzing the area (Az) under the curve with SPSS11.0 software. The area under the ROC curve was 0.91 (0.86, 0.95), P<0.05. MRAr proves to be an excellent modality to diagnose intraarticular adhesions of TMJ.

Adolescent↗
PubMed2005

Molecular genetic analysis for Ax phenotype of the ABO blood group system in Chinese.

BACKGROUND AND OBJECTIVES: To elucidate the molecular genetic background of the Ax phenotype in the Chinese population. MATERIALS AND METHODS: The ABO genes of eight Ax phenotype samples, four Ax and four AxB, were amplified by polymerase chain reaction (PCR) and were cloned, along with those of 10 random A(1) Chinese subjects. We analysed the ABO gene transcript structure and the sequences of two exons and one intron at the ABO locus. RESULTS: Among the four Ax phenotype samples, we identified one Ax02, two Ax03 and one novel Ax allele with the 543G > T mutation in the A102 background. Two of five family members also carry the allele. Of the four AxB phenotypes, one was designated as cis-AB-1/B101; the other three were shown to carry one B allele and one O with the nt261G deletion. The B alleles of the latter three were identical to B101 except for single point mutation at nt700C > G, nt640A > G and nt641T > C, respectively. The novel B101-like alleles were first associated with A(weak)B phenotypes. CONCLUSIONS: Two ABO*B(A) alleles and an Ax allele clearly differ from all previously reported ABO alleles, suggesting that the molecular genetic background of Ax is heterogeneous in the Chinese population.

ABO Blood-Group System↗
PubMed2004

Effects of a calcium channel blocker on spontaneous neural noise and gross action potential waveforms in the guinea pig cochlea.

The effects of the L-type Ca2+ channel blocker nimodipine on the spectrum of the spontaneous neural noise (SNN) and the waveform of the gross sound-evoked compound action potential (CAP) were investigated by perilymphatic perfusion in the guinea pig cochlea. Both the SNN and the CAP were reversibly suppressed by nimodipine. The percentage reduction in SNN was dose-dependent in a manner very similar to the results obtained with the measures of CAP threshold changes. The reduction in the peak SNN caused by 10 microM nimodipine was the same as that caused by 500 microM kainic acid, which totally eliminated any neural responses. For 1 microM nimodipine there was an apparent dissociation between the SNN and CAP changes such that the SNN could be markedly suppressed with only very small changes in CAP thresholds. These results imply that spontaneous release of neurotransmitter from the inner hair cell is more sensitive to block of calcium channels than evoked release. There was no evidence for any marked shift caused by nimodipine, in the position of the main (900 Hz) spectral peak in the SNN. Comparison of the CAP waveform before and after nimodipine perfusion showed that the CAP waveforms were unchanged despite the change in sensitivity. These data do not support the notion of any significant postsynaptic site of action of nimodipine. The data hence provide further support for an exclusively presynaptic role for L-type Ca2+ channels in the regulation of both evoked and spontaneous neurotransmitter release from inner hair cells.

Action Potentials↗
PubMed2004

Serologic prevalence of Toxoplasma gondii in field mice, Microtus fortis, from Yuanjiang, Hunan Province, People's Republic of China.

Antibodies to Toxoplasma gondii were investigated in serum samples of field mice, Microtus fortis, from Yuanjiang, Hunan Province, People's Republic of China. The modified agglutination test (MAT) incorporating formalin-fixed whole tachyzoites and mercaptoethanol was used to determine antibodies. Antibodies to T. gondii (MAT > or = 1:20) were found in 36 (29%) of 124 trapped mice. The antibody titers of positive sera (percentage in parentheses) were 1:20 (8.9), 1:40 (3.2), 1:80 (3.2), 1:160 (1.6), 1:320 (1.6), 1:640 (1.6), 1:1,280 (1.6), 1: 2,560 (0.8), and > 1:2,560 (6.5). No antibody to T. gondii was found in 104 sera of laboratory-bred M. fortis infected with Schistosoma japonicum between 1 and 45 days after infection.

Agglutination Tests↗
PubMed2002

Miniaturization of surface acoustic waves rotary motor.

This paper presents the experimental study of a miniaturized surface acoustic waves (SAWs) rotary motor and the theoretical calculation. After the first success in SAW rotary motor operating at 9.85 MHz, a smaller rotary motor is designed. With the operating frequency of 30 MHz and the driving voltage of 120 V(p-p), the motor can rotate at a speed of 270 rpm.

Acoustics↗
PubMed2001

Stationary multifaceted asymmetric radiation from the edge and improved confinement mode in a superconducting tokamak.

Stationary multifaceted asymmetric radiation from the edge (MARFE) is studied by gas-puffing feedback control according to an empirical MARFE critical density ( approximately 1.8 x 10(13) cm(-3)) in the HT-7 Ohmic discharges (where the plasma current I(p) is about 170 kA, loop voltage V(loop)=2-3 V, toroidal field B(T)=1.9 T, and Z(eff)=3-4). It is observed that an improved confinement mode characterized by D(alpha) line emissions drops and the line-averaged density increase is triggered in the stationary MARFE discharges. The mode is not a symmetric "detachment" state, because the quasi-steady-state poloidally asymmetric radiation (e.g., C III line emissions) still exists. This phenomenon has not been predicted by the current MARFE theory.

Journal Article↗
PubMed2001

Mitochondria-to-nucleus stress signaling induces phenotypic changes, tumor progression and cell invasion.

Recently we showed that partial depletion of mitochondrial DNA (genetic stress) or treatment with mitochondrial-specific inhibitors (metabolic stress) induced a stress signaling that was associated with increased cytoplasmic-free Ca(2+) [Ca(2+)](c). In the present study we show that the mitochondria-to-nucleus stress signaling induces invasive phenotypes in otherwise non-invasive C2C12 myoblasts and human pulmonary carcinoma A549 cells. Tumor-specific markers cathepsin L and transforming growth factor beta (TGFbeta) are overexpressed in cells subjected to mitochondrial genetic as well as metabolic stress. C2C12 myoblasts subjected to stress showed 4- to 6-fold higher invasion through reconstituted Matrigel membrane as well as rat tracheal xenotransplants in Scid mice. Activation of Ca(2+)-dependent protein kinase C (PKC) under both genetic and metabolic stress conditions was associated with increased cathepsin L gene expression, which contributes to increased invasive property of cells. Reverted cells with approximately 70% of control cell mtDNA exhibited marker mRNA contents, cell morphology and invasive property closer to control cells. These results provide insights into a new pathway by which mitochondrial DNA and membrane damage can contribute to tumor progression and metastasis.

Animals↗
PubMed2001

[Construction of three-dimensional finite element model of rat molar].

OBJECTIVE: This paper was to construct three-dimensional finite element model of rat molar, and to access mechanical stress distribution in the tooth and periodontia. METHODS: The first maxillary molar of adult rat was moved for 2 weeks with initial force of 40 g and 100 g. The histological specimen of tooth and surrounding structures were sectioned serially at 4 microns-thick slices in the coronary direction. The section's microscopic photographic images were made every 140 microns. The structural information of images was traced and fed into computer for three-dimensional reconstruction of the structure and finite element model. RESULTS: The stress distribution in periodontia which lies between tooth and alveolar bone was very complicated. CONCLUSION: The three-dimensional finite element model of rat molar is simple, precise, and effective for analyzing stress in tooth and periodontia.

Animals↗
PubMed2001

Glomerular extracellular matrix and growth factors in diffuse mesangial sclerosis.

UNLABELLED: Diffuse mesangial sclerosis, isolated (IDMS) or observed in the context of Denys-Drash syndrome (DDS) due to WT1 mutation, is characterized by early onset nephrotic syndrome progressing to renal failure. A striking morphological feature is the rapid development of glomerulosclerosis. THE AIMS OF OUR STUDY WERE: (1) to analyze the glomerular distribution of extracellular matrix (ECM) antigens at the early stage of DMS, (2) to determine the composition of the ECM accumulated within the mesangial areas and leading to glomerular sclerosis, and (3) to analyze the expression of growth factors, transforming growth factor-beta 1 (TGF beta 1) and platelet-derived growth factor A (PDGFA). In glomeruli of patients with IDMS and DDS, the glomerular basement membrane (GBM) expression of the heparan sulfate chain of heparan sulfate proteoglycan (HSPG) was decreased from the early stage of DMS, at a time when ECM proteins retained a normal distribution. In fully developed lesions, mesangial and subendothelial accumulation of collagenous and noncollagenous glycoproteins normally expressed in the mesangial area (types IV [alpha 1(IV)2 alpha 2(IV)] and VI collagen, beta 1 laminin, fibronectin, tenascin, and perlecan) increased with progression of mesangial sclerosis. This was associated with mesangial expression of proteins normally restricted to the GBM (agrin, alpha 1/alpha 5, beta 2, and gamma 1 laminin chains) and with accumulation of chondroitin sulfate proteoglycan. The distribution of the alpha 3-alpha 5 chains of type IV collagen was normal. Focal accumulation of types I, III, and V collagen was seen only in severely sclerotic glomeruli. Expression of growth factors TGF beta 1 and PDGFA was increased in 9 of 10 and 5 of 10 patients, respectively. Early decreased GBM expression of the heparan sulfate chain of HSPG could play a role in the proteinuria of DMS patients. Changes in the composition of the ECM accumulated within the mesangial areas are not specific. We speculate that deregulation of the expression of growth factors normally downregulated by WT1, is one of the factors responsible for the rapid and massive mesangial deposition of basement membrane material in DDS.

Child↗
PubMed2001

Evaluation of renal biopsy samples of patients with diabetic nephropathy.

OBJECTIVE: To evaluate the usefulness of renal biopsy in the overall management of patients with diabetes mellitus (DM), we examined the relationship between the clinical parameters and histopathological findings of renal biopsy samples. METHODS: Renal biopsy specimens were obtained from 109 type 2 diabetic patients with proteinuria. Samples were divided into the following two groups: Diabetic Nephropathy (DN) group (n=80) had typical diabetic lesions without other renal diseases, complication group (n=29) had diabetic lesions with other renal diseases. Furthermore, DN group was subdivided into two subgroups: slow progressive group (SP group, n=32), the level of serum creatinine (s-Cr) was normal at the time of renal biopsy and three years after renal biopsy, and fast progressive group (FP group, n=14), the level of s-Cr was normal at the time of renal biopsy but more than doubled three years after renal biopsy. RESULTS: The level of total protein was significantly lower and HbA1c significantly higher in the DN group than in the Complication group. However, other clinical parameters were not significantly different between the two groups. Urinary protein, systolic and diastolic blood pressure in FP group were significantly higher than in SP group. The percentage of sclerotic glomeruli, the severity of mesangial expansion, tubular injury and cell infiltration were significantly greater in FP than in SP group. CONCLUSIONS: Our results indicated that a complete evaluation of renal pathology in DM could not be made by clinical parameters only, and that the progression of DN could be accurately predicted by histopathological evaluation. Therefore, this study emphasizes the importance of renal biopsy in the overall management of patients with DM and/or DN.

Adult↗
PubMed2001

Image cytometry of cyclin D1: a prognostic marker for head and neck squamous cell carcinomas.

CCND1 gene amplification and cyclin D1 protein overexpression are indicators for poor prognosis in invasive head and neck carcinomas. Increased CCND1 gene dosage is a more sensitive prognostic factor than protein overexpression as evaluated by conventional immunohistochemical techniques. Qualitative immunohistochemistry cannot distinguish cyclin D1 overexpression accompanied by amplification of the CCND1 gene from overexpression associated with normal CCND1 gene copy number. To improve the sensitivity of cyclin D1 protein determination, we applied quantitative techniques of image analysis to evaluate cyclin D1 in 54 head and neck carcinomas. There was a significantly higher rate of occurrence of adverse events (P = 0.043) among patients with CCND1 gene amplification than among those without gene amplification. There was a strong association between CCND1 gene amplification (as detected by Southern blot analysis) and the highest nuclear score (by image cytometry of the immunostained tumor sections). The predominance of cells in the lowest nuclear score category was significantly associated with normal copy number (P = 0.005). Conversely, the highest nuclear score was a significant predictor of gene dosage (P = 0.02). Similarly, high nuclear score was a good predictor of death as the final outcome of the disease (P = 0.01). Although somewhat less accurate than Southern blotting, image cytometry of immunohistochemical cyclin D1 stain appears to be a promising tool that could be useful for other tumor marker expression studies.

Adult↗
PubMed2001

[Studies on polysaccharide of Cynomorium songaricum Rupr].

OBJECTIVE: To study the acidic heteropolysac charides of Cynomorium songaricum. METHOD: The polysaccharides were purified by Sephadex G-100 and G-150 gel column chromatography. Purity and molecular weight of the polysaccharides were determined by high performance gel permeation chromatography; neutral sugars composition were identified by PC, TLC and GC. Uronic acids were determined by carbazole method. RESULT: The molecular weight of SYP-A and SYP-B were estimated to be 3.1 x 10(5) and 2.8 x 10(5) respectively, and neutral sugars were composed of galactose, glucose, arabinose, rhamnose, mannose and ribose. The molar ratio for SYP-A and SYP-B were 5.1:4.1:1.6:1.0:0.5:0.3 and 5.2:4.2:1.5:1.0:0.5:0.2 respectively, The contents of uronic acids were 10.7% and 10.5% respectively. CONCLUSION: SYP-A and SYP-B are homogeneous acidic heteropolysaccharides.

Cynomorium↗
PubMed2001

[Studies on the anthraquinones of Cassia siamea].

AIM: To study the anthraquinone constituents of the stem of Cassia siamea. METHODS: The compounds were isolated by chromatography on silica gel, MHPLC, and identified on the basis of spectral analysis including IR, EI-MS, FAB-MS, 1HNMR, 13CNMR and DEPT. RESULTS: Three compounds were isolated and identified as: chrysophanol (I), chrysophanol-1-O-beta-D-glucopyranoside (II) and 1-[(beta-D-glucopyranosyl-(1-->6)-0-beta-D-glucopyranosyl) oxy]-8-hydroxyl-3-methy-9,10-anthraquinone (III). CONCLUSION: III is a new compound, II was obtained from this plant for the first time.

Anthraquinones↗