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Biomedical subjects

Yan Xiao

Publications and source records attributed to Yan Xiao.

At least 19 recordsLinked to original sources

Emergent CSCW systems: the resolution and bandwidth of workplaces.

In any collaborative work settings, people naturally develop physical tools and associated work processes that support the management of the interdependencies in information, materials, and social needs. Field studies of management of operating rooms pointed out that collaborative work is supported by an infrastructure that is composed of mostly non-computerized, physical components. The supporting infrastructure is jointly maintained and exploited, with constantly evolving patterns of usage, in response to complexity of coordination needs and the uncertain environment. To represent status and plans, users seem to invent structures based both on idiosyncratic preferences and on negotiated symbols. The fluidity and ease of restructuring workplaces to support collaborative work may be explained in part by the high resolution and bandwidth of workplaces: a large number of ways in which workers could structure their work and a high capacity to convey rich information and meanings quickly to collaborators. We argue that to support health care workers, designers of computer supported cooperative work (CSCW) systems should learn how the physical and perceptual properties of workplaces are exploited, and that CSCW systems should be designed to allow maximum freedom of restructuring and reconfiguring as part of workplaces to enhance bandwidth and resolution of representation and communication.

Cooperative Behavior↗

Quantum dots--a versatile tool in plant science?

An optically stable, novel class of fluorophores (quantum dots) for in situ hybridisation analysis was tested to investigate their signal stability and intensity in plant chromosome analyses. Detection of hybridisation sites in situ was based on fluorescence from streptavidin-linked inorganic crystals of cadmium selenide. Comparison of quantum dots (QDs) with conventional detection systems (Alexa 488) in immunolabeling experiments demonstrated greater sensitivity than the conventional system. In contrast, detection of QDs in in situ hybridisation of several plant chromosomes, using several high-copy sequences, was less sensitive than Alexa 488. Thus, semiconductor nanocrystal fluorophores are more suitable for immunostaining but not for in situ hybridisation of plant chromosomes.

Journal Article↗

A systematic review of the literature on multidisciplinary rounds to design information technology.

Multidisciplinary rounds (MDR) have become important mechanisms for communication and coordination of care. To guide design of tools supporting MDR, we reviewed the literature published from 1990 to 2005 about MDR on information tools used, information needs, impact of information tools, and evaluation measures. Fifty-one papers met inclusion criteria and were included. In addition to patient-centric information tools (e.g., medical chart) and decision-support tools (e.g., clinical pathway), process-oriented tools (e.g., rounding list) were reported to help with information organization and communication. Information tools were shown to improve situation awareness of multidisciplinary care providers, efficiency of MDR, and length of stay. Communication through MDR may be improved by process-oriented information tools that help information organization, communication, and work management, which could be achieved through automatic extraction from clinical information systems, displays and printouts in condensed forms, at-a-glance representations of the care unit, and storing work-process information temporarily.

Humans↗

A generalized analysis of capillary flows in channels.

Investigations on the motion of a fluid in capillary geometries have been extensively reported in the literature using both experimental and theoretical approaches. In this paper, the theories for capillary flow are generalized to a unified nonlinear second-order differential equation which takes the effects of the entrance, the inertial forces, and the dynamic contact angle into account. An analytical solution of the differential equation is obtained in the form of a double Dirichlet series. The readily evaluated analytical solution is compared with experimental and numerical results in the literature, which shows a good agreement. It is demonstrated that this analytical approach can be used to predict capillary flows for a wide range of fluids and parallel-plate and tube geometries in a unified manner.

Journal Article↗

In vivo disruption of TGF-beta signaling by Smad7 leads to premalignant ductal lesions in the pancreas.

TGF-beta has been postulated to play an important role in the development of pancreatic cancers. More than 50% of human pancreatic cancers bear mutations of Sma- and Mad-related protein (Smad) 4, a critical protein required for TGF-beta signaling. To evaluate the in vivo function of TGF-beta in the development of pancreatic cancers, we generated a transgenic mouse model with pancreas-specific expression of Smad7, a specific inhibitor of TGF-beta signaling. Through the use of elastase I promoter, we directed the tissue specific expression of exogenous Smad7. Consistently, the exogenous Smad7 was detected only in the pancreas in the transgenic mice, and, furthermore, phosphorylation of Smad2 was blocked in the pancreatic tissues. At 6 months of age, most transgenic animals developed premalignant ductal lesions in the pancreas, with characteristics of pancreatic intraepithelial neoplasia (PanIN), a precursor to invasive pancreatic cancers. The premalignant lesions of the pancreas were accompanied by accelerated proliferation of the ductal epithelium and acinar cells, as well as increased fibrosis around the ductal lesions. This study not only demonstrated that in vivo inactivation of TGF-beta signaling is implicated in the development of early stage of pancreatic cancers, but also provided a promising animal model useful for the investigation and intervention of pancreatic cancers in humans.

Animals↗

Neuronal chemorepellent Slit2 inhibits vascular smooth muscle cell migration by suppressing small GTPase Rac1 activation.

The Slits are secreted proteins with roles in axonal guidance and leukocyte migration. On binding to Robo receptors, Slit2 repels developing axons and inhibits leukocyte chemotaxis. Slit2 is cleaved into Slit2-N, a protein tightly binding to cell membranes, and Slit2-C, a diffusible fragment. In the present study, we characterized the functional role of Slit2-N in vascular smooth muscle cells (VSMCs) and the cell association properties of 2 truncated versions of Slit2-N. Here, we document for the first time that Slit2-N is a chemorepellent of VSMCs. Intact blood vessels expressed Slit2 and Robo receptors as demonstrated by immunohistochemistry and quantitative real time PCR. Recombinant Slit2-N prevented the platelet-derived growth factor (PDGF)-stimulated migration of VSMCs. Slit2-N also abrogated PDGF-mediated activation of small guanosine triphosphatase (GTPase) Rac1, a member of the Rho GTPase superfamily of proteins involved in regulating the actin cytoskeleton. Furthermore, Slit2-N inhibited the PDGF-induced formation of lamellipodia, a crucial cytoskeletal reorganization event for cell motility. Slit2-N had no effect on the PDGF-mediated increase in DNA synthesis determined by [3H]thymidine uptake, suggesting that VSMC growth is unaffected by Slit2. Analysis of 2 engineered Slit2-N fragments (Slit2-N/1118 and Slit2-N/1121) indicated that 3 amino acids upstream of the putative cleavage site (Arg1121, Thr1122) are involved in the association of Slit2-N to the cell membrane. Our data assign a novel functional role to Slit2 in vascular function and show that cell guidance mechanisms that operate in the developing central nervous system are conserved in VSMCs.

Animals↗

Expression of vascular endothelial growth factors A and C in human pancreatic cancer.

AIM: To study the expression of vascular endothelial growth factor A (VEGF-A) and VEGF-C and to determine whether the presence of VEGF-A and VEGF-C was associated with the clinicopathologic characteristics of pancreatic cancer. METHODS: VEGF-A and VEGF-C mRNA transcripts were examined by Northern blot in 6 human pancreatic cancer cell lines and 8 normal pancreatic tissues and 8 pancreatic carcinoma specimens. The expression of VEGF-A and VEGF-C proteins was examined by Western blot in the tested cell lines and by immunohistochemical stain in 50 pancreatic carcinoma samples. RESULTS: VEGF-A and VEGF-C mRNA transcripts were present in all the 6 human pancreatic cancer cell lines. Immunoblotting revealed the presence of VEGF-A and VEGF-C proteins in all the cell lines. Northern blot analysis of total RNA revealed 3.0-fold and 3.6-fold increase in VEGF-A and VEGF-C mRNA transcript in the cancer samples, respectively. Immunohistochemical analysis confirmed the expression of VEGF-A and VEGF-C in cancer cells within the tumor mass. Immunohistochemical analysis of 50 pancreatic cancer tissue samples revealed the presence of VEGF-A and VEGF-C immunoreactivity in 50% and 80% of the cancer tissue samples, respectively. The presence of VEGF-A in these cells was associated with larger tumor size and enhanced local spread (c2 = 6.690, P = 0.035<0.05) but was not associated with decreased patient survival. However, the presence of VEGF-C in the cancer cells was associated with increased lymph node metastasis (c2 = 5.710, P = 0.017 < 0.05), but was not associated with decreased patient survival. There was no correlation between the expression of VEGF-A and VEGF-C in the same cancer cells. CONCLUSION: VEGF-A and VEGF-C are commonly overexpressed in human pancreatic cancer and may contribute to tumor growth and lymph node metastasis. There is no relationship between the expression of VEGF-A and VEGF-C in pancreatic cancer.

Adult↗

Communication technology in trauma centers: a national survey.

The relationship between information and communication technology (ICT) and trauma work coordination has long been recognized. The purpose of the study was to investigate the type and frequency of use of various ICTs to activate and organize trauma teams in level I/II trauma centers. In a cross-sectional survey, questionnaires were mailed to trauma directors and clinicians in 457 trauma centers in the United States. Responses were received from 254 directors and 767 clinicians. Communication with pre-hospital care providers was conducted predominantly via shortwave radio (67.3%). The primary communication methods used to reach trauma surgeons were manual (56.7%) and computerized group page (36.6%). Computerized group page (53.7%) and regular telephone (49.8%) were cited as the most advantageous devices; e-mail (52.3%) and dry erase whiteboard (52.1%) were selected as the least advantageous. Attending surgeons preferred less overhead paging and more cellular phone communication than did emergency medicine physicians and nurses. Cellular phones have become an important part of hospital-field communication. In high-volume trauma centers, there is a need for more accurate methods of communicating with field personnel and among hospital care providers.

Analysis of Variance↗

Mentors decrease compliance with best sterile practices during central venous catheter placement in the trauma resuscitation unit.

BACKGROUND: In the academic trauma unit during initial evaluation and resuscitation of trauma victims, central venous catheters are often placed by multiple operators. There are few data on compliance with accepted, standard sterile practices during such procedures. METHODS: Prospective data were tabulated from video capture of 144 consecutive central venous catheterizations in a trauma resuscitation unit, during peak hours, by a team of trained video technicians. The physicians were surgical and emergency medicine residents. The number of primary operators (trainees) and secondary operators (mentors) for each line was recorded from the video analysis, as well as physician adherence to the use of maximum barrier precautions (MBP; sterile gown, gloves, full operative drape, cap, and mask). Procedures were stratified by level of urgency: Emergent (n = 7), semi-emergent (n = 20), and elective (n = 113). RESULTS: The subclavian vein was used for 73% of the elective catheter placements. For elective central venous catheters, 99 of 113 primary operators (88%) observed MBP, whereas only 31 of 45 secondary operators (69%) did so (p < or = 0.01). Among the 45 elective central venous catheters placed with a secondary operator, there were four instances of frank contamination (9%). CONCLUSIONS: Secondary operators, typically trauma surgery attendings, trauma/critical care fellows, or senior surgical residents, function as mentors in academic institutions and act as role models. Secondary operators participated in many of the studied cases, yet failed to demonstrate consistent use of MBP. In elective central venous catheter placement, those where there was the greatest opportunity to follow MBP, we observed a statistically significant difference in compliance rate between the primary and secondary operators. The study suggests the need to address the performance of the secondary operators and to educate them, as although they may be technically experienced in placing central venous catheters, they may comply less consistently with MBP.

Catheterization, Central Venous↗

Video-based ergonomic analysis to evaluate thoracostomy tube placement techniques.

BACKGROUND: Thoracostomy for relief of pneumo- or hemothorax may be performed emergently at the bedside, in the emergency department or trauma area, often in nonideal circumstances. We hypothesized that ergonomic analysis of thoracostomy techniques can identify areas for potential improvement in patient and operator safety. METHODS: Interviews with Subject Matter Experts (SME) provided steps in the task of thoracostomy; 44 thoracostomies (emergent and elective) were video-recorded and reviewed by SMEs. Ergonomic analyses evaluated surgical performance techniques using video clips. RESULTS: Risks to the patient and operator included instrument-tray positioning and instrument content. Analyses of video records revealed that despite SME-survey consensus, operators inconsistently followed recommended techniques. CONCLUSIONS: Discrepancies between SME-recommended and observed practice are prevalent, with simple ergonomic problems impeding performance, and creating risks for patients and operators. Video-based ergonomic analysis is a rich source for identifying task performance problems and potential solutions.

Chest Tubes↗

[Effects of jinlongshe granules on apoptosis of MKN-45 human gastric cancer cells orthotopically transplanted in nude mice].

OBJECTIVE: To assess the effects of Jinlongshe Granules (JLSG) on tumor growth of gastric carcinoma. METHODS: Fifty nude mice orthotopically transplanted with MKN-45 human gastric cancer cells were divided into five groups: untreated group, 5-fluorouracil (5-FU)-treated group and high-, medium-, and low-dose JLSG-treated groups. Corresponding antitumor drugs were administered in each group except the untreated group. The antitumor effects in vivo were evaluated. Cell cycle distribution and apoptosis of MKN-45 human gastric cancer cells were determined by using flow cytometry (FCM) and Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining assay. The ultrastructure of MKN-45 gastric cancer cells was observed by transmission electron microscope. RESULTS: In the mice treated with high-, medium-, and low-dose JLSG, the growth inhibition rates of gastric cancer were 68.13%, 55.94% and 50.31% respectively, and this antitumor effect was dose-dependent. In the mice treated with intraperitoneal injection of 5-FU, the growth inhibition rate of gastric cancer was 53.43% and not much different from those treated with JLSG. The apoptotic rates in the high-, medium-, and low-dose JLSG-treated groups were 22.81%, 28.27% and 38.54% respectively, in a dose-dependent manner, with the cell cycle arrested at G(0)/G(1) phase. An Annexin V-FITC/PI staining assay revealed that the percentages of early apoptotic cells in the three dose JLSG-treated groups were all significantly higher than that in the 5-FU-treated group, whereas the late apoptotic and necrotic cells were much more in the 5-FU-treated group than those in the three dose JLSG-treated groups. CONCLUSION: Jinlongshe Granules exert an inhibiting effect on MKN-45 human gastric cancer cell.

Animals↗

[Effects of Rhizoma kaempferiae volatile oil on tumor growth and cell cycle of MKN-45 human gastric cancer cells orthotopically transplanted in nude mice].

OBJECTIVE: To evaluate the effects of Rhizoma kaempferiae volatile oil on tumor growth and cell cycle of MKN-45 human gastric cancer cells orthotopically transplanted in nude mice. METHODS: One hundred and five nude mice orthotopically transplanted with MKN-45 human gastric cancer cells were randomly divided into seven groups: untreated group, normal saline-treated group, dissolvant-treated group, cyclophosphamide (CTX)-treated group and high-, medium-, and low-dose Rhizoma kaempferiae volatile oil-treated groups. Corresponding interventions were implemented in each group except the untreated group. The antitumor effects in vivo were evaluated. Cell cycle distribution and apoptosis of MKN-45 human gastric cancer cells were determined by using flow cytometry (FCM). The ultrastructure of MKN-45 gastric cancer cells was observed by a transmission electron microscope. RESULTS: In the high-, medium-, and low-dose Rhizoma kaempferiae volatile oil-treated groups, the growth inhibition rates of gastric cancer were 57.2%, 28.0% and 5.0% respectively, and the gastric cancer cells were arrested at G(0)/G(1) phase. This antitumor effect was dose-dependent. The apoptotic cells occurred more frequently in the high-dose Rhizoma kaempferiae volatile oil-treated group and the CTX-treated group than those in the medium- and low-dose Rhizoma kaempferiae volatile oil-treated groups. CONCLUSION: The Rhizoma kaempferiae volatile oil is an effective composition for growth inhibition of gastric cancer, and its mechanism may be related to regulating the cell cycle and inducing apoptosis.

Animals↗

[Influence of beta-amyloid peptide on cell membrane lipids and cholinergic receptors in human neuroblastoma SH-SY5Y cells].

OBJECTIVE: To study the effects of beta-amyloid peptide (Abeta) on cell membrane lipids and cholinergic receptors of human neuroblastoma cells. METHODS: Human SH-SY5Y neuroblastoma cells were treated with different concentrations of Abeta(1-42) with and without pretreatment of vitamin E. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] reduction, lipid peroxidation, protein oxidation and phospholipids were measured by spectrophotometry. Levels of cholesterol and unbiquinone were determined by high-performance liquid chromatography (HPLC). The numbers of cholinergic receptor binding sites were determined by receptor binding assay and the protein levels of nicotinic receptor alpha3 and alpha7 subunits were studied by Western blotting. RESULTS: SH-SY5Y cells showed decreased reduction rates of MMT and phospholipids, and increased lipid peroxidation and protein oxidation after exposure to Abeta (0.1 micromol/L) as compared to the control. The number of cholinergic receptor binding sites, the protein level of nicotinic receptor alpha3 and alpha7 subunits and the content of ubiquinone decreased in cells treated with high dose of Abeta (1 micromol/L). Although the level of cholesterol was not changed in any way, vitamin E partially prevented the neurotoxic effects of Abeta. CONCLUSION: beta-amyloid peptide reduces the level of cell membrane lipids and cholinergic receptors in human SH-SY5Y neuroblastoma cells, likely through the induction of an enhanced oxidative stress.

Amyloid beta-Peptides↗

[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↗

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↗

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↗

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↗

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↗