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Biomedical subjects

Yan Xiao

Publications and source records attributed to Yan Xiao.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Clinical study of human cytomegalovirus infection in colony forming unit-megakaryocyte in patients with idiopathic thrombocytopenic purpura].

OBJECTIVE: Idiopathic thrombocytopenic purpura (ITP) is a hemorrhagic disease in children with blood platelets redundant destruction caused by chaotic immunological mechanism. However, some patients with ITP with negative platelet-associated antibody and ineffective adrenal cortical hormone therapy probably have special pathogenesis. It is indicated that the human cytomegalovirus (HCMV) can incubate in haemopoietic stem cell/ancestral cell to inhibit its generation and differentiation. Therefore, the study was designed to investigate HCMV-late mRNA expression in megakaryoblast for the purpose of examining the pathogenesis of ITP and to examine the effectiveness of ganciclovir on ITP. METHODS: Colony forming unit-megakaryocyte (CFU-MK) of 46 ITP patients with HCMV infection were incubated. Reverse transcription-polymerase chain reaction (RT-PCR) was subsequently used for HCMV-late mRNA detection. Ganciclovir therapy was given to both positive group and negative group for comparison of therapeutic effectiveness. RESULTS: Nineteen out of 46 CFU-MK culture cell specimens with positive HCMV-DNA by PCR or positive CMV-IgM by enzyme linked immunosorbent assay (ELISA) from serum of peripheral blood showed positive for HCMV-late mRNA. While, the remaining 27 were negative. Sixteen positive responders to ganciclovir therapy were observed amongst those with positive HCMV-DNA. Whereas, only 4 positive responders to ganciclovir therapy were noticed amongst those with negative HCMV-DNA. The curative effectiveness in positive group was significantly higher than that in negative group (P < 0.01). CONCLUSION: HCMV can directly infect CFU-MK, which might be one of the mechanisms responsible for ITP. Ganciclovir is an effective therapy resulting in an increase in thrombocyte in ITP patients whose HCMV-late mRNA was positive in their CFU-MK.

Adolescent↗
PubMed2006

[Effect of beta-amyloid peptides on alpha-7 nicotinic receptor status in astrocytes and neurons, and its relationship to pathogenesis of Alzheimer's disease].

OBJECTIVE: To study the alterations of alpha-7 nicotinic receptor (nAChR) status in human brain tissues with Alzheimer's disease (AD) and mouse brain tissues with Swedish APP670/671 gene mutation, and to study the effect of beta-amyloid peptides (A-beta) on alpha-7 nAChR status in cultured astrocytes and neurons. METHODS: Postmortem brain tissues from patients with AD and mouse brain tissues with Swedish APP mutation were collected. The expression of alpha-7 nAChR on astrocytes and neurons was detected by immunohistochemistry (ABC method). The alpha-7 nAChR protein level was measured by Western blotting. On the other hand, cultured astrocytes and neurons were treated with different concentrations of A-beta 25 - 35. The alpha-7 nAChR protein level was then measured. RESULTS: Increased number of astrocytes surrounding senile plaques was observed in AD brain tissues. In AD brain tissues, as compared to age-matched controls, alpha-7 nAChR protein level was increased in astrocytes, but decreased in neurons. High level of alpha-7 nAChR protein was also observed in mouse brain tissues with APP mutation. Exposure to A-beta 25 - 35 induced an increase (up to 38%) in alpha-7 nAChR protein level in astrocytes but a decrease (up to 32%) in neurons. CONCLUSIONS: Decrease in alpha-7 nAChR level in neurons may be related to the pathogenesis of AD, whereas an increased level of alpha-7 nAChR in astrocytes, as induced by excessive A-beta, may represent a compensatory neuroprotective response.

Aged↗
PubMed2005

A review and a framework of handheld computer adoption in healthcare.

Wide adoption of mobile computing technology can potentially improve information access, enhance workflow, and promote evidence-based practice to make informed and effective decisions at the point of care. Handheld computers or personal digital assistants (PDAs) offer portable and unobtrusive access to clinical data and relevant information at the point of care. This article reviews the literature on issues related to adoption of PDAs in health care and barriers to PDA adoption. Studies showed that PDAs were used widely in health care providers' practice, and the level of use is expected to rise rapidly. Most care providers found PDAs to be functional and useful in areas of documentation, medical reference, and access to patient data. Major barriers to adoption were identified as usability, security concerns, and lack of technical and organizational support. PDAs offer health care practitioners advantages to enhance their clinical practice. However, better designed PDA hardware and software applications, more institutional support, seamless integration of PDA technology with hospital information systems, and satisfactory security measures are necessary to increase acceptance and wide use of PDAs in healthcare.

Access to Information↗
PubMed2005

Oxidative stress induced by beta-amyloid peptide(1-42) is involved in the altered composition of cellular membrane lipids and the decreased expression of nicotinic receptors in human SH-SY5Y neuroblastoma cells.

The neurotoxic effects and influence of beta-amyloid peptide (Abeta)(1-42) on membrane lipids and nicotinic acetylcholine receptors (nAChRs) in human SH-SY5Y neuroblastoma cells were investigated in parallel. Exposure of the cultured cells to varying concentrations of Abeta(1-42) evoked a significantly decrease in cellular reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5,diphenyl tetrazolium bromide), together with enhanced lipid peroxidation and protein oxidation. Significant reductions in the total contents of phospholipid and ubiquinone-10, as well as in the levels of the alpha3 and alpha7 subunit proteins of nAChRs were detected in cells exposed to Abeta(1-42). In contrast, such treatment had no effect on the total cellular content of cholesterol. Among these alterations, increased lipid peroxidation and decreased levels of cellular phospholipids were most sensitive to Abeta(1-42), occurring at lower concentrations. In addition, when SH-SY5Y cells were pretreated with the antioxidant Vitamin E, prior to the addition of Abeta(1-42), these alterations in neurotoxicity, oxidative stress, composition of membrane lipids and expression of nAChRs were partially prevented. These findings suggest that stimulation of lipid peroxidation by Abeta may be involved in eliciting the alterations in membrane lipid composition and the reduced expression of nAChRs associated with the pathogenesis of AD.

Alzheimer Disease↗
PubMed2005

Rad GTPase attenuates vascular lesion formation by inhibition of vascular smooth muscle cell migration.

BACKGROUND: Rad (Ras associated with diabetes) GTPase is a prototypic member of a new subfamily of Ras-related GTPases with unique structural features, although its physiological role remains largely unknown. In the present study, we characterized the Rad function in vascular smooth muscle cells (VSMCs) and the influence of adenovirus-mediated Rad (Ad-Rad) gene delivery on vascular remodeling after experimental angioplasty. METHODS AND RESULTS: We documented for the first time that neointimal formation using balloon-injured rat carotid arteries was associated with a significant increase in Rad expression as determined by immunohistochemistry and quantitative real-time reverse-transcriptase polymerase chain reaction. The levels of Rad expression in VSMCs were highly induced by platelet-derived growth factor and tumor necrosis factor-alpha. Morphometric analyses 14 days after injury revealed significantly diminished neointimal formation in the Ad-Rad-treated carotid arteries compared with Ad-GFP or PBS controls, whereas the mutated form of Rad GTPase, which can bind GDP but not GTP, increased neointimal formation. Overexpression of Rad significantly inhibited the attachment and migration of VSMCs. In addition, Rad expression dramatically reduced the formation of focal contacts and stress fibers in VSMCs by blocking the Rho/ROK signaling pathway. CONCLUSIONS: Our data clearly identified Rad GTPase as a novel and critical mediator that inhibits vascular lesion formation. Manipulation of the Rad signaling pathway may provide new therapeutic approaches that will limit vascular pathological remodeling.

Actins↗
PubMed2005

Spectrophotometric study of the inclusion complex between beta-cyclodextrin and dibenzoyl peroxide and its analytical application.

The noncovalent interaction of dibenzoyl peroxide and beta-cyclodextin (beta-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied. The results showed that beta-CD reacts with dibenzoyl peroxide to form a 2:1 host-guest complex with an apparent formation constant of 2.5 x 10(4)mol(-2)L(2). The beta-CD reacts with benzoic acid to form a 1:1 host-guest complex with an apparent formation constant of 6.9 x 10(2)mol(-1)L after the dibenzoyl peroxide was reduced by hydroxyl ammonium. Based on the enhancement of the absorbance of dibenzoyl peroxide produced through complex formation, a spectrophotometric method for determination of dibenzoyl peroxide in bulk aqueous solution in the presence of beta-CD was developed. A linear relationship between the absorbance and dibenzoyl peroxide concentration was obtained in the range of 0.300-50.0 microg mL(-1). Linear regression equation of the calibration graph C=0.02926+53.25 A, with a correlation coefficient of 0.9984 and a relative standard deviation (R.S.D.) of 3.4%. The detection limit was 0.200 microg mL(-1), and the recovery was from 98.00 to 105.0%. The proposed method was used to determine the dibenzoyl peroxide in the flour with satisfactory results. The principal advantage of the proposed method is its excellent selectivity based on molecule recognition of beta-CD.

Benzoyl Peroxide↗
PubMed2005

Artifacts and collaborative work in healthcare: methodological, theoretical, and technological implications of the tangible.

Although modeled as knowledge work with emphasis on data flow and decision making, healthcare is delivered in the context of a highly structured physical environment, with much effort and emphasis placed on physical and spatial arrangement and re-arrangement of workers, patients, and materials. The tangible aspects of highly collaborative healthcare work have profound implications for research and development of information and communication technology (ICT) despite the tendency to model work as flow of abstract data items. This article reviews field studies in healthcare and other domains on the role of artifacts in collaborative work and draws implications in three areas: methodological, theoretical, and technological. In regard to methodologies, assessment of new ICT and development of user requirements should take into account how artifacts are used and exploited to facilitate collaborative work. In regard to theories, the framework of distributed cognition provides a starting point for modeling the contribution and exploitation of physical artifacts in supporting collaborative work. In regard to technology, design and deployment of new technology should support the functions provided by physical artifacts replaced or disrupted by new technology, and profitable ways for new technology to support collaborative work by embedding ICT into existing infrastructure of physical artifacts.

Artifacts↗
PubMed2005

Simultaneous determination of carvedilol and ampicillin sodium by synchronous fluorimetry.

The carvedilol and ampicillin sodium were simultaneously determined by the synchronous fluorimetry. With excitation wavelength at 254 nm, the maximum emission wavelengths of carvedilol and ampicillin sodium were at 357 and 426 nm, respectively. Because the emission spectra of carvedilol and ampicillin sodium were overlapped partially, carvedilol and ampicillin sodium cannot be determined directly by normal fluorimetric method. However, the synchronous fluorimetry can be used for determining both drugs simultaneously without separation procedure. The (Delta)(lambda) = 80 nm was used. Iso-propanol was selected as sensing reagent. Effects of pH, organic solvents and foreign ions on the determination of both drugs were studied. The linear relationship was obtained between the relative fluorescence intensity and concentration of carvedilol and ampicillin sodium in the range of 0.005-0.1 and 5.0-70.0 microg ml(-1), respectively. The linear regression equation of calibration graph for carvedilol is C = 0.000151F - 0.00210, and for ampicillin sodium is C = 0.0770F - 2.62. The correlation coefficient of linear regression equation is 0.9995 for carvedilol and 0.9998 for ampicillin sodium, respectively. The detection limit is 1 ng ml(-1) for carvedilol and 1 microg ml(-1) for ampicillin sodium. The relative standard deviations of carvidelol and ampicillin sodium are 2.47 and 1.61%, respectively. The recovery is from 96.0 to 103.0% for carcvedilol and from 98.0 to 105.0% for ampicillin sodium. This method was rapid, simple and highly sensitive for the determination of carvedilol and ampicillin sodium without pre-separation. The results obtained by this method agreed with those by the official methods. This method can be used for the determination of carvedilol and ampicillin sodium in the medicine dosage.

2-Propanol↗
PubMed2005

An algorithm for processing vital sign monitoring data to remotely identify operating room occupancy in real-time.

We developed an algorithm for processing networked vital signs (VS) to remotely identify in real-time when a patient enters and leaves a given operating room (OR). The algorithm addresses two types of mismatches between OR occupancy and VS: a patient is in the OR but no VS are available (e.g., patient is being hooked up), and no patient is in the OR but artifactual VS are present (e.g., because of staff handling of sensors). The algorithm was developed with data from 7 consecutive days (122 cases) in a 6 OR trauma center. The algorithm was then tested on data from another 7 consecutive days (98 cases), against patient in- and out-times captured by OR surveillance videos. When pulse oximetry, electrocardiogram, and temperature readings were used, OR occupancy was correctly identified 96% (95% confidence interval [CI] 95%-97%) and OR vacancy >99% of the time. Identified patient in- and out-times were accurate within 4.9 min (CI 4.2-5.7) and 2.8 min (CI 2.3-3.5), respectively, and were not different in accuracy from times reported by staff on OR records. The algorithm's usefulness was demonstrated partly by its continued operational use. We conclude that VS can be processed to accurately report OR occupancy in real-time.

Algorithms↗
PubMed2005

In Situ Fourier transform infrared spectroscopic study of the thermal degradation of isotactic poly(propylene).

The conformational change of isotactic poly(propylene) (iPP) during the thermal degradation process has been carefully studied by in situ Fourier transform infrared (FT-IR) spectroscopy. This new method of studying thermal degradation of iPP not only shows the conventional kinetic parameter information of thermal degradation such as the degradation activation energy DeltaE and the degradation factor n, which are in accord with the results of traditional thermogravimetry experiments, but also indicates that many significant molecular structure changes occur during the thermal degradation process that come from some characteristic absorption band changes of in situ FT-IR. A multivariate approach, principal components analysis (PCA), is applied to the analysis of infrared (IR) data, and the results further confirm the multi-step processes of the thermal degradation of iPP. Above all, this is a new application to polymer thermal degradation by in situ FT-IR that connects the intermediate conformational change with final results during thermal degradation.

Algorithms↗
PubMed2005

Simultaneous determination of dopamine and carvedilol in human serum and urine by first-order derivative fluorometry.

A sensitive and selective method for simultaneous determination of carvedilol and dopamine was described. The emission wavelengths of carvedilol and dopamine were at 354 nm and 314 nm with the excitation at 290 nm, respectively. The determination of carvedilol and dopamine by normal fluorometry was difficult because the emission spectra of carvedilol and dopamine were overlapped seriously. The first derivative peaks of carvedilol and dopamine were at 336 nm and 302 nm, respectively. The linear regression equations of the calibration graphs of carvedilol and dopamine were C = 0.000557H-0.00569 and C = 0.00438H-0.0812, with the correlation coefficients were 0.9953 and 0.9988, respectively. The liner range for the determination of carvedilol was 0.002 microg ml(-1) to 0.02 microg ml(-1), and 0.05 microg ml(-1) to 0.6 microg ml(-1) for dopamine. The detection limits were 1 ng ml(-1) for carvedilol and 0.04 microg ml(-1) for dopamine, respectively. The relative standard derivative (RSD) of 4.38% and 4.35% was observed for carvedilol and dopamine, respectively. The recovery of carvedilol was from 95.00% to 106.7% in human serum and from 97.50% to 105.0% in urine sample. The recovery of dopamine was from 100.0% to 102.5% in human serum and from 97.50% to 105.0% in urine sample. This method is simple and can be used for determination of carvedilol and dopamine in human serum and urine sample with satisfactory results.

Calibration↗
PubMed2005

Simultaneous determination of carvedilol and ampicillin sodium by first-derivative fluorometry in the presence of human serum albumin.

A sensitive and selective method for the simultaneous determination of carvedilol and ampicillin sodium (AS) in the presence of human serum albumin (HSA) is described. The maximum emission wavelengths of carvedilol and AS are at 357 nm and 426 nm with excitation at 254 nm, respectively. The first-derivative peaks of carvedilol and AS were at 337 nm and 398 nm, respectively. The linear-regression equations of the calibration graphs of carvedilol and AS were C = 0.0001H - 0.0063 and C = 1.530H - 43.84; the correlation coefficients were 0.9990 and 0.9986, respectively. The detection limits were 1 ng ml(-1) for carvedilol and 23 microg ml(-1) for AS, respectively. The effects of the pH, the stability of carvedilol and AS and foreign ions on the determination of carvedilol and AS were examined. The recoveries of carvedilol and AS were measured. This method is simple and can be used for the determination of carvedilol and AS in human serum and urine samples with satisfactory results.

Adrenergic beta-Antagonists↗
PubMed2005

[5, 10-methylenetetrahydrofolate reductase polymorphism in three nationalities of Guizhou in China].

OBJECTIVE: To study the genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) among the Han, Buyi and Miao populations in Guizhou and to provide genetic data for establishment of the genetic polymorphism bank of Guizhou Minorities. METHODS: The technique of polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) was used to detect the genotype and allele frequencies at two mononucleotide sites (677 and 1298) of MTHFR among the Han population in Libo county, the Buyi population in Libo county and the Miao population in Leishan county. RESULTS: At the site of 677, the T allele frequencies were found to be 22.8%, 16.1%, 10.6%, for the Han, Buyi, Miao populations respectively. At the site of 1298, the C allele frequencies were 28.9%, 39.1%, 48.7% for the Han, Buyi, Miao populations respectively. The frequencies for the combined heterozygote of 677CT/1298AC were 16.66%, 22.7%, 11.1% for the three populations respectively. Moreover, one case with combined homozygote of 677TT/1298CC was seen in the Miao population. CONCLUSION: The polymorphisms of the two mononucleotide sites (677 and 1298) of MTHFR are diverse in different populations. The C allele frequencies at the site of MTHFR 1298 of the Miao population in Leishan county and the Buyi population in Libo county are high, and the C allele frequency in the Miao population is higher than those hitherto reported in literature.

Base Sequence↗
PubMed2005

Interleukin-1alpha, 6 regulate the secretion of vascular endothelial growth factor A, C in pancreatic cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF, namely VEGF-A) is an angiogenic polypeptide and VEGF-C is a lymphangiogenic polypeptide that has been implicated in cancer growth, invasion and metastasis. Several cytokines and growth factors play an important part in cancer progression. These cytokines and growth factors are the principal mediators of cancer cells--stromal cell interaction, which is critical for invasion of cancer cells to the surrounding tissues and metastatic dissemination to distant organs. In this study, we studied VEGF-A, C expression in cultured human pancreatic cancer cell lines and whether the presence of VEGF-A, C in the cell lines is regulated by cytokines interleukin-1alpha(IL-1alpha), and interleukin-6 (IL-6). METHODS: We used Northern blot and Western blot methods to analyze expression of the gene and protein of VEGF-A, C in all 6 tested cell lines (ASPC-1, CAPAN-1, MIA-PaCa-2, PANC-1, COLO-357 and T3M4) respectively. To analyze what is the regulator for this VEGF-A, C expression in pancreatic cancer, we used the reverse transcription-polymerase chain reaction (RT-PCR) method to analyze VEGF-A, C expression in cultured human pancreatic cancer cell lines (CAPAN-1 and COLO-357) under the stimulation with IL-1alpha(10 microg/L) or IL-6 (100 microg/L). RESULTS: Northern blot analysis revealed the presence of the 4.1 kb VEGF-A mRNA transcript and 2.4-kb VEGF-C mRNA transcript in all 6 tested cell lines. Immunoblotting with highly specific anti-VEGF-A, anti-VEGF-C antibody revealed the presence of a molecular weight of 43-kDa VEGF-A protein and 55-kDa VEGF-C protein in all the cell lines. RT-PCR analysis revealed the levels of the VEGF-A and VEGF-C gene were 1-2 fold and a 1-fold increase in the COLO-357 cell line by stimulation with IL-1alpha, however, no effect was found in the CAPAN-1 cell line. The levels of the VEGF-A and VEGF-C gene were 2-5 fold and a 1-fold increase in the CAPAN-1 cell line by stimulation with IL-6, but no effect was found in the COLO-357 cell line. CONCLUSION: These findings suggested that the expression of VEGF-A, C and their regulation by IL-1alpha, IL-6 in pancreatic cancer contributes to the lymphatic and distant metastasis and the disease progression.

Blotting, Northern↗
PubMed2005

[Dendrolimus spp. damage monitoring by using NOAA/AVHRR data].

This paper approached the feasibility of quantitatively monitoring Dendrolimus spp. damage by using NOAA/ AVHRR data. The damaged rate of needle leaf was used to represent Dendrolimus spp. harming degree, and < 30%, 30%-60% and > 60% of damaged rate was defined as low, medium and severe harming degree, respectively. The correlation equation of damaged rate and normalized vegetation index (NDVI) was established, based on the ground spectrum observation. The NDVI was 0.8823 when no damage occurred. A relative NDVI value of damaged to undamaged area was used to express the remote sensing index of low, medium and severe harming degree. The index was 1 for undamaged forest, and 0.78-1, 0.57-0.78 and < 0.57 for low, medium and severe harming degrees, respectively. The mixed pixels were separated by linear addable vertical vegetation index in the monitoring, and the quantitative monitoring and analysis was accomplished for years when the three damage degrees happened. It was shown that AVHRR data could be more available in quantitatively monitoring and analyzing serious damage, while low degree damage was difficult to distinguish by AVHRR data, due to the differences of surface properties and atmospheric influences, as well as the lower space resolution of NOAA/AVHRR. The damaged area estimated by AVHRR was 12.1%-14.3% lower than that by TM.

Animals↗
PubMed2004

Lactoferrin down-regulates G1 cyclin-dependent kinases during growth arrest of head and neck cancer cells.

The molecular mechanism of lactoferrin-induced cell growth inhibition is incompletely understood. Studying head and neck cancer cells treated with human lactoferrin, we observed growth arrest in three of four cell lines tested. This growth arrest was caused by cell cycle inhibition at the G0-G1 checkpoint. Lactoferrin-induced growth inhibition was associated with a large increase in p27 protein, accompanied by decreased phosphorylation of retinoblastoma protein, and suppression of cyclin E. Decreased levels of phosphorylated Akt were also observed in lactoferrin-sensitive cell lines after treatment. These findings suggest that in head and neck cancer cells the growth inhibitory effects of lactoferrin are mediated through a p27/cyclin E-dependent pathway that may be modulated in part by changes in Akt phosphorylation.

Cell Cycle Proteins↗
PubMed2004

Cardiomyocyte-restricted peroxisome proliferator-activated receptor-delta deletion perturbs myocardial fatty acid oxidation and leads to cardiomyopathy.

Fatty acid oxidation (FAO) is a primary energy source for meeting the heart's energy requirements. Peroxisome proliferator-activated receptor-delta (PPAR-delta) may have important roles in FAO. But it remains unclear whether PPAR-delta is required for maintaining basal myocardial FAO. We show that cre-loxP-mediated cardiomyocyte-restricted deletion of PPAR-delta in mice downregulates constitutive expression of key FAO genes and decreases basal myocardial FAO. These mice have cardiac dysfunction, progressive myocardial lipid accumulation, cardiac hypertrophy and congestive heart failure with reduced survival. Thus, chronic myocardial PPAR-delta deficiency leads to lipotoxic cardiomyopathy. Together, our data show that PPAR-delta is a crucial determinant of constitutive myocardial FAO and is necessary to maintain energy balance and normal cardiac function. We suggest that PPAR-delta is a potential therapeutic target in treating lipotoxic cardiomyopathy and other heart diseases.

AMP-Activated Protein Kinases↗