Biomedical subjects
Publications and source records attributed to Wei Sun.
Three-component reactions of aldehydes, amines, and diethyl phosphite catalyzed by Mg(ClO4)2 or molecular iodine afforded the corresponding alpha-amino phosphonates in excellent yields under mild reaction conditions.
The purpose of this study was to detect changes in coagulation and fibrinolysis of post-severe acute respiratory syndrome (SARS) Chinese patients with osteonecrosis, investigate the aetiology of post-SARS osteonecrosis (ON), and select the sensitive molecular markers for identifying the susceptible population. For this study, blood samples were collected from 88 patients with post-SARS ON and 52 healthy people. Activated partial thromboplastin time (APTT), protein C (PC), antithrombin III (AT-III), plasminogen activator inhibitor (PAI), activated protein C resistance (APC-R), plasminogen (PLG), von Willebrand's factor(vWF), D-dimer (D-D), fibrinogen (Fib), and homocysteine (HCY) were examined by enzyme-linked immunosorbent assay (ELISA). We noted that blood agents of patients with ON changed obviously. APTT, PC, AT-III, PAI, APC-R, and PLG were significantly different between the two groups. Hypercoagulation and hypofibrinolysis were found in patients with post-SARS ON. Therefore, these examinations can be used to screen a population susceptible to ON. Measurements of APTT, PC, AT-III, PAI, APC-R, and PLG are sensitive blood tests for screening purposes.
OBJECTIVE: To investigate the effects of norcantharidin (NCTD) on angiogenesis of human gallbladder carcinoma and its anti-angiogenic mechanisms. METHODS: Human gallbladder carcinoma cells of the line GBC-SD were cultured. BALB/c nude mice were inoculated subcutaneously with the GBC-SD cells and then randomly divided into 6 groups: NCTD group, injected intraperitoneally with 1/5 of the LD(50) of NCTD twice a week for 6 weeks; 5-fluorouracil (5-FU) group, injected intraperitoneally with 1/5 of the LD(50) of 5-FU twice a week for 6 weeks; endostatin (ES) group, intraperitoneally with ES; NCTD + 5-FU group, injected intraperitoneally with 1/5 of the LD(50) of NCTD and 1/5 of the LD(50) of 5-FU twice a week for 6 weeks; NCTD + ES group, injected intraperitoneally with 1/5 of the LD(50) of NCTD and ES twice a week for 6 weeks; and normal saline (NS) group (control group), injected with NS. The mice were killed in the 7th week. The tumors were taken out to measure their volumes and undergo microscopy. SABC method of immunohistochemistry was used to measure the microvessel density (MVD) and the protein expression of the angiogenesis-related factors: proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), angiopoietin (Ang)-2, thrombospondin (TSP), and tissue inhibitor of metalloprotease (TIMP)(2). Suspension of single tumor cell was prepared to examine the cell apoptosis by flow cytometry. RT-PCR was used to examine the mRNA expression of PCNA, VEGF, Ang-2, TSP, and TIMP2. RESULTS: (1) The MVD of the NCTD group was 4.12 +/- 1.4, significantly lower than those of the 5-FU group (15.8 +/- 5.9) and control group (17.6 +/- 3.2) (both P < 0.01), but not significantly different from those of the NCTD + 5-FU group (3.8 +/- 1.7), ES group (4.5 +/- 2.1), and NCTD + ES group (2.9 +/- 1.5) (all P > 0.05). The mice treated with NCTD showed significantly smaller tumor volume, lower PCNA protein expression, higher apoptotic rate, and higher PCNA/apoptosis ratio (P < 0.05 or P < 0.01), and significant correlation between MVD and tumor volume and between MVD and PCNA/apoptosis ratio (both P < 0.05). (2) The protein expression of VEGF and of Ang-2 of the NCTD group were both significantly lower than those of the control and 5-FU groups (all P < 0.01), however, not significantly different from those of the ES, NCTD + 5-FU, and NCTD + ES groups; and the protein expression of TSP and of TIMP2 of the NCTD group were both significantly higher than those of the control and 5-FU groups (all P < 0.01), however, not significantly different from those of the ES, NCTD + 5-FU, and NCTD + ES groups. MVD was positively correlated with VEGF and Ang-2 expression and negatively correlated with the expression of TSP and TIMP2 (all P < 0.05). (3) In comparison with the control group, the mRNA expression of VEGF and of Ang-2 of the tumor cells of the NCTD group were both significantly lower and the mRNA expression of TIMP2 was significantly higher. CONCLUSION: NCTD down-regulates the expression of the angiogenic factors, such as VEF|GF and Ang-2, and up-regulates the expression of the anti-angiogenic factors, such as TDP and TIMP2, thus inhibiting the angiogenesis in tumor, such as human gallbladder carcinoma, and further inhibiting the growth of tumor.
OBJECTIVE: To investigate the hematological changes and related gene mutation of post-severe acute respiratory syndrome (SARS) patients with osteonecrosis so as to find the sensitive molecular symbols for early screening of the high risk populations. METHODS: Fast peripheral venous blood samples were collected from 61 post-SARS patients with osteonecrosis, 25 males and 36 females, aged 30.4 (20 - 60), and 52 sex and age-matched healthy persons as controls. ELISA was used to detect the coagulation and fibrinolysis indicators: activated partial thromboplastin time (APTT), protein C (PC), antithrombin III (AT-III), plasminogen activator inhibitor (PAI), activated protein C resistance (APC-R), plasminogen (PLG), von Willebrand factor (VWF), D-dimer (D-D), and fibrinogen (Fib). Real-time PCR was used to detect the mutation of factor V G1601A (FV Leiden) and prothrombin G20210A. RESULTS: The levels of PC, AT-III, and PLG of the osteonecrosis group were 85% +/- 34%, 84 +/- 29%, and 69 +/- 23%, significantly lower than that of the control group (109% +/- 20%, 104% +/- 14%, and 94% +/- 15% respectively, all P < 0.01). PAI of the osteonecrosis group was 16 U/ml +/- 14 U/ml, significantly higher than that of the control group (8.0 U/ml +/- 4.3 U/ml, P < 0.01). The percentage of patients with abnormal indicators was 99.5% (54/61) in the osteonecrosis group, significantly higher than that of the control group (36.5%, 19/52, P < 0.01). The percentage of patients with 3 or more abnormal indicators was 72.1% (44/61) in the osteonecrosis group, significantly higher than that of the control group (17.3%, 9/52, P < 0.01). No mutations of F V Leiden and prothrombin G20210A was found in both groups. CONCLUSION: Trends of hypercoagulation and hypofibrinolysis exist in the post-SARS patients with osteonecrosis. APTT, PC, AT-III, and PLG can be used as sensitive indicator for screening high risk populations of osteonecrosis.
Ventricular septal defect (VSD) accounts for the largest number of birth congenital heart defects in human, but the genetic programs that control ventricular septation are poorly understood. To identify differentially expressed genes between ventricular septal defect and normal ventricular septum myocardium, we have undertaken suppression subtractive hybridization (SSH) and generated reciprocal cDNA collections of representative mRNAs specific to human heart with ventricular septal defect versus normal control. Following SSH, 1378 clones were sequenced and found to derive from 551 different genes. These predominately expressed genes included genes involved in energy metabolism, cell cycle and growth, cytoskeleton and cell adhesion, LIM protein, zinc finger protein, and development. It is anticipated that further study of genes identified will provide insights into their specific roles in the etiology of VSD, even in cardiac development, aging, and disease.
OBJECTIVES: This paper presents up to 5 years post-program outcomes of Project Towards No Drug Abuse (Project TND), a drug abuse prevention program conducted in South California alternative high school system during years 1994-1999. METHODS: The effects of a 9-session health motivation--social skills--decision-making curriculum were evaluated. Twenty-one schools recruited were randomly assigned to standard care (control), classroom only, or a classroom plus semester-long school-as-community component. Last 30-day use of cigarettes, alcohol, marijuana, and hard drugs were assessed at three time intervals: short-term (year 1), middle-term (years 2 or 3), and long-term (years 4 or 5). Multilevel random coefficients modeling were employed to estimate the adjusted levels of substance use. RESULTS: Among 1578 baseline subjects, follow-up data were available for 68% (year 1), 66% (years 2 or 3), and 46% (years 4 or 5) of subjects, respectively. Results revealed significant positive long-term program effects for hard drug use at year 4 or 5 for the two program interventions (P = 0.02). CONCLUSIONS: Project TND reduced hard drug use in the 46% who were successfully followed. It is the first program to demonstrate long-term self-reported behavioral effects on hard drug use among high-risk youth by using a school-based, limited-session model.
PURPOSE: To evaluate the use of breath-hold three-dimensional (3D) steady-state free precession (SSFP) coronary magnetic resonance angiography (MRA) in patients with coronary artery disease (CAD) in comparison with conventional coronary x-ray angiography (XRA). MATERIALS AND METHODS: Twenty-eight patients with suspected CAD were examined with the use of a breath-hold 3D-SSFP-MRA sequence and conventional XRA. To assess the accuracy of MRA, two clinicians who were blinded to patient information independently reviewed the MRA and XRA data, which were presented in a randomized order. To identify discrepancies between MRA and XRA, and assess features of coronary lesions on MRA, two additional clinicians examined MRA and XRA data that were presented side by side, divided into proximal, mid, and distal segments, and compared them segment by segment. RESULTS: The sensitivity and specificity for diagnosing significant coronary stenoses (> 50% diameter narrowing) were 64% and 94%, respectively. At sites of coronary lesions identified on XRA, bright signals and enlarged vessel profiles, in addition to the characteristic narrow lumen, were frequently observed on MRA. CONCLUSION: Breath-hold SSFP coronary MRA has good specificity but inconclusive sensitivity in diagnosing significant coronary stenoses, and provides important image features for depicting coronary lesions.
PURPOSE: To investigate delayed hyperenhancement during different healing stages of myocardial infarct with and without reperfusion in a pig model. MATERIALS AND METHODS: Twelve pigs were studied. Six pigs were subjected to permanent right coronary artery (RCA) occlusion, and the other six were subjected to transient 90-minute RCA occlusion. In vivo MRI including first-pass perfusion and myocardial delayed enhancement (MDE) was performed at four, eight, 12, and 24 hours, and eight days after the artery occlusion. The MDE scan was repeated four times, two to 32 minutes after contrast administration. RESULTS: For all six pigs without reperfusion, the four-hour MRI showed transmural perfusion defect and no delayed hyperenhancement; from eight hours on, delayed hyperenhancement appeared and its spatial extent gradually increased until it became transmural hyperenhancement at eight days. However, in all six pigs with reperfusion, hyperenhancement was present at every stage from four hours to eight days. Pathology confirmed the existence of infarct at various stages of healing irrespective of reperfusion status. CONCLUSION: Occlusive hyperacute infarct did not exhibit any delayed hyperenhancement, which indicates that perfusion plays an important role in delayed enhancement at the hyperacute stage.
Severe acute respiratory syndrome (SARS) is a severe infectious disease that has affected many countries and regions since 2002. A novel member of the coronavirus, SARS-CoV, has been identified as the causative agent. However, the pathogenesis of SARS is still elusive. In this study, we used 2-D DIGE and MS to analyze the protein profiles of plasma from SARS patients, in the search for proteomic alterations associated with the disease progression, which could provide some clues to the pathogenesis. To enrich the low-abundance proteins in human plasma, two highly abundant proteins, albumin and IgG, were first removed. By comparing the plasma proteins of SARS patients with those of a normal control group, several proteins with a significant alteration were found. The up-regulated proteins were identified as alpha-1 acid glycoprotein, haptoglobin, alpha-1 anti-chymotrypsin and fetuin. The down-regulated proteins were apolipoprotein A-I, transferrin and transthyretin. Most of the proteins showed significant changes (up- or down-regulated) in the progressive phase of disease, and there was a trend back to normal level during the convalescent phase. Among these proteins, the alterations of fetuin and anti-chymotrypsin were further confirmed by Western blotting. Since all the up-regulated proteins identified above are well-known inflammation inhibitors, these results strongly suggest that the body starts inflammation inhibition to sustain the inflammatory response balance in the progression of SARS.
Normal Chinese Liver Proteome Expression Profile is one of the major parts of Human Liver Proteome Project. Before starting the studies, it is necessary to examine the interindividual variation of normal liver proteome and evaluate the minimal size of samples for proteomic analysis. In this study, normal liver samples from ten individual volunteers were collected and the proteome profiles of these samples were analyzed using 2-D difference gel electrophoresis (DIGE) combined with MALDI-TOF/TOF MS. The individual liver tissue lysates were labeled with Cy3 and Cy5 while the pooled sample was labeled with Cy2 as an internal standard, which minimized gel-to-gel variation. After analysis by the DeCyder software, up to 2056 protein spots were detected on the master gel. The CV of standardized abundance was calculated for the protein spots that were matched across all ten gels. The CV values of these protein spots ranged from 6.4 to 108.5% and the median CV was approximately 19%, which demonstrated that the protein expression of normal liver among different individuals was relatively stable. The eight proteins with CV values over 50% were identified which would be a caveat when considering these proteins as potential disease-related markers. Moreover, the one-way ANOVA feature showed a correlation between sample size and individual variations. The results showed that when the sample size exceeded 7, the individual variations were not significant to the whole pool. Our results are an important basis for liver protein expression profiles and comparative proteomics of liver disease.
The structure of the endosomal-associated protein, Hrs, has been determined with cryo-electron microscopy. Hrs interacts with a number of proteins, including SNAP-25 and STAM1, forming a complex that binds ubiquitin moieties. Analytical ultracentrifugation studies revealed that Hrs exists as a hexamer. The symmetry and the structure of the hexameric form of Hrs were determined with the single-particle reconstruction method. Hrs comprises three antiparallel dimers with a central core and distinct caps on either end. Crystal structures of VHS and FYVE domains fit into the Hrs end caps in the EM density map. Thus, the location of domains that interact with the endosomal membrane, the VHS, FYVE, and C-terminal domains, facilitates the anchorage of Hrs to the membrane, initiating the functional processes of Hrs on the endosome. Based on our model, the Hrs hexamer interacts with the membrane and acts as a "master molecule" that presents multiple sites for protein binding.
A recent US-China National Science Foundation-sponsored workshop on biomanufacturing reviewed the state-of-the-art of an array of new technologies for producing scaffolds for tissue engineering, providing precision multi-scale control of material, architecture, and cells. One broad category of such techniques has been termed solid freeform fabrication. The techniques in this category include: stereolithography, selected laser sintering, single- and multiple-nozzle deposition and fused deposition modeling, and three-dimensional printing. The precise and repetitive placement of material and cells in a three-dimensional construct at the micrometer length scale demands computer control. These novel computer-controlled scaffold production techniques, when coupled with computer-based imaging and structural modeling methods for the production of the templates for the scaffolds, define an emerging field of computer-aided tissue engineering. In formulating the questions that remain to be answered and discussing the knowledge required to further advance the field, the Workshop provided a basis for recommendations for future work.
Sphingosine-1-phosphate (S1P), a sphingolipid metabolite, promotes cell proliferation and survival whereas its precursor, sphingosine, has the opposite effects. However, much remains unknown about their regulation. Here we identify a novel human ceramidase (haCER2) that regulates the levels of both sphingosine and S1P by controlling the hydrolysis of ceramides. haCER2 is localized to the Golgi complex and is highly expressed in the placenta. High ectopic expression of haCER2 caused fragmentation of the Golgi complex and growth arrest in HeLa cells due to sphingosine accumulation. Low ectopic expression of haCER2 increased S1P without sphingosine accumulation, promoting cell proliferation in serum-free medium. This proliferative effect was suppressed by dimethylsphingosine, an inhibitor of the S1P formation, or by the RNA interference (RNAi) -mediated inhibition of S1P(1,) a G-protein-coupled receptor for S1P. The RNAi-mediated down-regulation of haCER2 enhanced the serum deprivation-induced growth arrest and apoptosis of HeLa cells, which was inhibited by addition of exogenous S1P. Serum deprivation up-regulated both haCER2 mRNA and activity in HeLa cells. haCER2 mRNA is also up-regulated in some tumors. Taken together, these results suggest that haCER2 is important for the generation of S1P and S1P-mediated cell proliferation and survival, but that its overexpression may cause cell growth arrest due to an accumulation of sphingosine.
Evaluation of yttrium exposure in biological samples has not been fully examined. To evaluate yttrium nephrotoxicity, yttrium chloride was orally administered to male Wistar rats and the urine volume (UV) and N-acetyl-beta-D-glucosaminidase (NAG) and creatinine excretion (Crt) were measured in 24-h urine samples. The urinary yttrium concentration and excretion rate were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES). Large significant decreases of UV (>30%) and Crt (>10%) were observed at yttrium doses of 58.3-116.7 mg per rat, but no significant NAG changes was observed. This response pattern shows that a high yttrium dosage alters glomerular function rather than the proximal convoluted tubules. A urinary yttrium excretion rate of 0.216% and good dose-dependent urinary excretion (r=0.77) were confirmed. These results suggest that urinary yttrium is a suitable indicator of occupational and environmental exposure to this element, an increasingly important health issue because recent technological advances present significant potential risks of exposure to rare earth elements. We propose that the ICP-AES analytical method and animal experimental model described in this study will be a valuable tool for future research on the toxicology of rare earth elements.
Current antidotal regimens for organophosphorus compound (OP) poisoning consist of a combination of pretreatment with a spontaneously reactivating AChE inhibitor such as pyridostigmine bromide, and postexposure therapy with anticholinergic drugs such as atropine sulfate and oximes such as 2-PAM chloride (Gray, 1984). Although these antidotal regimens are effective in preventing lethality of animals from OP poisoning, they do not prevent postexposure incapacitation, convulsions, performance deficits, or, in many cases, permanent brain damage (Dunn and Sidell, 1989). These problems stimulated the development of enzyme bioscavengers as a pretreatment to sequester highly toxic OPs before they reach their physiological targets. Several studies over the last two decades have demonstrated that exogenously administered human serum butyrylcholinesterase (Hu BChE) can be used successfully as a safe, efficacious, and single prophylactic treatment to counteract the toxicity of OPs. It also has potential use for first responders (civilians) reacting to terrorist nerve gas release, pesticide overexposure, or succinylcholine-induced apnea. A dose of 200 mg of Hu BChE in humans is envisioned as a prophylactic treatment that can protect from exposure of 2-5 x LD50 of nerve agents (Ashani, 2000).
A novel voltammetric method for the determination of microamounts of fish sperm double-stranded (ds) DNA based on its interaction with phenosafranine (PSF) is proposed in this paper. In a pH 3.5 Britton-Robinson (B-R) buffer solution, PSF had a well-defined second-order derivative linear-sweep voltammetric reductive peak at -0.32 V (vs. SCE) on a mercury electrode. After the addition of dsDNA into the PSF solution, the reductive peak current decreased significantly without a shift of the peak potential, and no new peak appeared. The experiment results showed that a new supramolecular complex was formed after the interaction of dsDNA with PSF, which resulted in a decrease of the diffusion coefficient, and then a decrease of the reductive peak current. The interaction conditions and the electrochemical detection conditions were carefully investigated. Under the optimal conditions, the decrease of the peak current was proportional to the dsDNA concentration in the range 1.0 - 40.0 microg/mL with the linear regression equation DeltaI(p)''(nA) = 32.59C(microg/mL) - 4.03 (n = 13, gamma = 0.998) and a detection limit of 0.25 microg/mL (3 sigma). The interaction mechanism was considered based on the aggregation of the dsDNA-PSF supramolecular complex; the stoichiometry of this supramolecular complex was calculated based on voltammetric data with a binding number of 3 and a binding constant of 2.76 x 10(12). This method was successfully applied to the determination of synthetic samples and the polymerase chain reaction (PCR) product of the nopaline synthase gene (NOS) DNA from genetically modified organisms (GMOs) with satisfactory results.
Previously studied inhibitors of aldose reductase were largely from two chemical classes, spirosuccinamide/hydantoins and carboxylic acids. Each class has its own drawbacks regarding selectivity, in vivo potency, and human safety; as a result, the pathogenic role of aldose reductase in diabetic retinopathy remains controversial. ARI-809 is a recently discovered aldose reductase inhibitor (ARI) of a new structural class, pyridazinones, and has high selectivity for aldose versus aldehyde reductase. To further test the possible pathogenic role of aldose reductase in the development of diabetic retinopathy, we examined the retinal effects of this structurally novel and highly selective ARI in insulinized streptozotocin-induced diabetic rats. ARI-809 treatment was initiated 1 month after diabetes induction and continued for 3 months at a dose that inhibited the polyol pathway in the retina of diabetic rats to a similar extent as sorbinil, a poorly selective hydantoin ARI previously shown to prevent retinopathy in this model. ARI-809 improved survival, inhibited cataract development, normalized retinal sorbitol and fructose, and protected the retina from abnormalities that also occur in human diabetes: neuronal apoptosis, glial reactivity, and complement deposition. Because ARI-809 is a novel chemotype highly selective for aldose reductase, these results support the notion that aldose reductase is the key relay that converts hyperglycemia into glucose toxicity in neural and glial cell types in the retina.
The technology of digital image guidance systems has transformed many aspects of neurosurgery, including intracranial tumor surgery, functional neurosurgery, and spinal surgery. Despite the central role of imaging studies in diagnosis and treatment planning, intraoperative image guidance has so far had very limited application to the surgical correction of craniofacial deformities, particularly those associated with craniosynostosis. The authors report an example of the marriage of computer-assisted design methods to a commercially available neurosurgical image-guidance system in the treatment of a case of anterior plagiocephaly due to unilateral coronal synostosis. They discuss the steps that must yet be taken to make this technology applicable to the management of craniosynostosis in infants.