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Biomedical subjects

D Gu

Publications and source records attributed to D Gu.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Spatial structure and pattern of Nilaparvata lugens population in large-scale].

Brown planthopper(BPH), Nilaparvata lugens, is a major pest of rice. Its spatial distribution of different generations in Guangdong Province was studied by using variograms. The results showed that this population distributed in a clump pattern in rice fields during the 1st rice season. 3 generations of this population had different spatial structures, with the clump range of 400 km, 200 km and 205 km respectively in the 1st rice season. The simulation distribution maps of BPH, which was interpolated by Ordinary Kriging, showed that the density of BPH populations in west Guangdong province were higher than that in the east. The effect of sampling size on the spatial structure of BPH was not significant.

Animals↗
PubMed2001

[The development and application of computer-aided bone histomorphometry system].

The aim of this study is to develop a Computer-aided Bone Histomorphometry System. The method is based on the Micro-graphical Digital System composed of microscope, digital camera, computer and related programs. The methodology was developed to measure the basic data on each image of visual field of hard bone tissue with computer-assistance. Following this, the parameters of bone volume, bone structure and bone metabolism were calculated based on the standardization of bone histomorphometry. Such method has been used in the experimental and clinical studies of osteoporosis to predict the fracture risk and evaluate the drug effect.

Bone Density↗
PubMed2001

[Evaluation on the effect of cardiovascular prevention program in Fangshan, Beijing].

OBJECTIVE: To evaluate the effect of cardiovascular prevention program in Fangshan, Beijing (BFCP) from 1991-1999. METHODS: BFCP was a comprehensive community trial covering 120,000 residents in five communities, including three as intervention communities (IC), and two as control communities (CC), in Fangshan, suburb of Beijing. The program was implemented under both population and high risk individual strategies, focusing on health education and hypertension control. The main intervention measures were as follows: (1) network setup; (2) health education and promotion; (3) health professional training; (4) detection and management of hypertensive patients. RESULTS: Baseline, midterm and final cross-sectional surveys were conducted in the year 1991, 1995 and 1999, respectively. After 9-year intervention, improvement was found in population of IC versus CC (P < 0.01 or P < 0.05) for knowledge, attitude and behavior of CVD prevention, awareness on hypertension, treatment and control rates, as well as the quantity of dietary intake of protein, potassium and calcium. Risk factors such as systolic blood pressure, diastolic blood pressure, rates of smoking and alcohol drinking declined in the population in IC versus CC (P < 0.01). The average morbidity and mortality of stroke were 18.7% (u = 2.81, P < 0.01) and 17.7% (u = 2.91, P < 0.01), significantly lower in the IC versus CC. No significant difference was identified on the morbidity and mortality of coronary heart diseases between IC and CC. CONCLUSION: The comprehensive community prevention approach was feasible and effective in the prevention and control of cardiovascular diseases in rural populations in China.

Adult↗
PubMed2000

Sterols and inhibitors of sterol transport modulate the degradation and secretion of macrophage ApoE: requirement for the C-terminal domain.

Macrophage-derived apoE, produced in the vessel wall, may have important effects during atherogenesis. The production of apoE by macrophages can be regulated at a transcriptional level by cellular differentiation state, cytokines and sterol loading. In addition, there are post-transcriptional and post-translational loci for regulation. We have recently identified an intermediate density cell membrane fraction in which the degradation of apoE can be modulated by sterols. Suppressing degradation of apoE in this fraction by pre-incubating cells in sterols led to enhanced apoE secretion. In this report we demonstrate that the suppressive effect of sterols on the degradation of newly synthesized apoE in this fraction depends on the presence on its C-terminal domain, by studying a macrophage cell line transfected to express a mutant form of apoE in which amino acids beyond amino acid 202 were deleted. In addition, two modulators of cellular sterol transport, progesterone and U1866A, inhibited the degradation of full-length apoE. In contrast, incubation of cells in the acyl-CoA:cholesterol acyltransferase inhibitor S58035 did not influence apoE degradation. As would be predicted based on the results of degradation assays, U1866A, but not S58035, increased the secretion of apoE from a cell line transfected to constitutively express full-length apoE cDNA. The effect of U1866A on apoE degradation, like the effect of sterol, required the presence of the apoE C-terminal domain. Our results indicate that alteration of intracellular sterol homeostasis by pre-incubation in sterols or by drugs that modify the subcellular transport of sterol, modulates the susceptibility of apoE to degradation and that this modulation requires the presence of C-terminal lipid binding domains.

Apolipoproteins E↗
PubMed2000

Outcome of an institutional sexual offender treatment program: a comparison between treated and matched untreated offenders.

Data from a sexual offender treatment program operated by the Correctional Service of Canada at the Regional Psychiatric Center (Saskatoon) supported the conclusion that cognitive behavioral treatment can reduce sexual offense recidivism. The study compared 296 treated and 283 untreated offenders followed for a mean of 6 years after their release. An untreated comparison subject was located for each treated offender on three dimensions: (a) age at index offense, (b) date of index offense, and (c) prior criminal history. Data were analyzed using tests of proportion, survival analysis, and analysis of offender Criminal Career Profiles. Over a mean follow-up period of almost 6 years, convictions for new sexual offenses among treated offenders were 14.5% versus 33.2% for untreated offenders. During the follow-up period, 48% of treated offenders remained out of prison compared to 28.3% of untreated offenders. Time series comparisons of treated and comparison samples also showed that treated men reoffended at significantly lower rates after 10 years. A Criminal Career Profile (CCP) was constructed by taking the Age at First Conviction and plotting the offender's successive lengths of time free against time incarcerated. Pre- and posttreatment slopes of the CCP were lower for both groups posttreatment; however, the degree of change was significantly greater for the treated group, indicating a greater reduction in criminal activity among these offenders. Taken together, the results of all three analytic techniques supported the efficacy of appropriate correctional treatment for effective reduction of recidivism.

Adult↗
PubMed2000

Expression of ErbB receptors during pancreatic islet development and regrowth.

We have characterized expression of the ErbB receptor family and one of its ligands, heregulin, in an effort to identify molecules associated with pancreatic development and regeneration. In addition to studying expression during fetal pancreatic development, we have also studied expression during pancreatic regeneration in the interferon-gamma (IFNgamma)-transgenic mouse, which exhibits significant duct cell proliferation and new islet formation. These studies demonstrate significant expression of the ErbB2, ErbB3, and ErbB4 receptors, in addition to heregulin isoforms, in the developing murine fetal pancreas. We also report significant ductal expression of these proteins during IFNgamma-mediated pancreatic regeneration. This striking expression was absent in 1-week-old neonates, but was clearly visible in pups by 5 weeks of age. These data therefore indicate that ErbB receptor and ligand expression decline by birth in both the IFNbeta-transgenic and non-transgenic mice, and that expression resumes early in postnatal life in the IFNbeta-transgenic mice. The expression of ErbB receptor family members at sites of islet development and regrowth suggests that these molecules might be relevant to these processes.

Animals↗
PubMed2000

[Hostility behavior as risk factor of coronary heart disease].

OBJECTIVE: To explore the relationships between hostility, and the risks of coronary-prone behavior and the clusters of unhealthy behaviors in individuals with different levels of hostility. METHODS: A cross-sectional study was carried out among 1 010 male employees from two factories in Beijing Capital Steel and Iron Company in 1997. Data on major risks of cardiovascular, other social-demographic factors and levels of hostility by Cook-Medley Scales were collected. RESULTS: Body mass index, amounts of cigarette smoking and alcohol drinking were significantly increased (P < 0.01) with a characteristic of reduced social support from one's colleagues, when individual's level of hostility increased. In addition, less years of education, higher prevalence of other chronic diseases (P < 0.05) and clustering of various unhealthy behaviors were found related to the increase of individual's hostility. The odds ratio in the group with highest hostility was 2.37 times higher than in the lowest one, after confounding effects from age, blood pressure, education level, status of chronic disease and social support being adjusted. No significant differences on both systolic and diastolic blood pressures among groups with different levels of hostility were discovered. CONCLUSION: The association between hostility, coronary-prone risk behavior and cluster of unhealthy behaviors suggested that hostility might increase the risk of coronary heart diseases through affecting individual's behavior.

Adolescent↗
PubMed2000

[Cost-effectiveness analysis of Beijing Fangshan cardiovascular prevention program in 1992 - 1997].

OBJECTIVE: To determine whether a community-based cardiovascular disease (CVD) intervention program, undertaken over six years, was cost-effective. METHODS: Based on Beijing Fangshan Cardiovascular Disease Comprehensive Prevention Program, the cost for intervention and expenditure saved from caring for CVD in the communities with intervention from 1992 to 1997 were calculated, and cost-effectiveness analysis was performed using disability-adjusted life years (DALYs) gained as an indicator of effectiveness. RESULTS: The cost for one DALY gained reduced gradually from 1992 to 1997, with an average ratio of cost to effectiveness of four to one (4:1). It cost annually 1,586.00, 1,380.20, -2,350.80, -905.30, -1,495.60 and -1,766.70 RMB yuan for one life-year saved, from 1992 to 1997 respectively, in a gradually decreasing trend with the increase in length of intervention. After intervention for two years, ratio of cost to effectiveness has become negative since 1994, which meant a positive benefit from intervention. Sensitivity analysis showed that ratio of cost to effectiveness was little sensitive to the changes in discount rate, weight of age and increase in cost of hospitalization for stroke and coronary heart disease, which reflected its reliability. CONCLUSION: Community-based comprehensive intervention for CVD in rural population is cost-effective.

Aged↗
PubMed1999

Immunization levels among premature and low-birth-weight infants and risk factors for delayed up-to-date immunization status. Centers for Disease Control and Prevention Vaccine Safety Datalink Group.

CONTEXT: Studies have noted that health care professionals may not conform to proper immunization schedules for premature and low-birth-weight infants in the United States. Little is known about the success of current efforts to immunize these high-risk infants. OBJECTIVE: To describe current immunization practices for premature and low-birth-weight infants and ascertain risk factors for poor immunization status, using large population-based data sources. DESIGN AND SETTING: Cohort and case-control analyses of immunization data tracked from March 1991 through March 1997 for 3 large health maintenance organizations (HMOs) participating in the Centers for Disease Control and Prevention's Vaccine Safety Datalink project. PARTICIPANTS: A total of 11580 low-birth-weight and premature infants were enrolled from birth to age 2 months; 6832 of these were continuously enrolled from birth to age 24 months. At age 2 months, there were 173373 full-term, normal-birth-weight infants enrolled as controls; at age 24 months, there were 103 324. MAIN OUTCOME MEASURES: Age-specific immunization status by prematurity and birth weight (<1500 g, 1500-2500 g, born at <38 weeks' gestation with birth weight of >2500 g, or full-term with normal birth weight) and patient characteristics associated with up-to-date status. RESULTS: At each age, infants weighing less than 1500 g at birth had lower up-to-date immunization levels than other infants. At age 6 months, 52% to 65% of infants weighing less than 1500 g were up-to-date at each of the 3 HMOs compared with 69% to 73% of those weighing 1500 to 2500 g, 66% to 80% of premature infants weighing more than 2500 g, and 65% to 76% of full-term, normal-birth-weight infants. By age 24 months, 78% to 86% of infants weighing less than 1500 g were up-to-date, significantly less than heavier infants, who had levels of 84% to 89%. Well-child preventive care strongly predicted immunization status, while concomitant pulmonary disease did not. CONCLUSIONS: Our data suggest that infants born prematurely are vaccinated at levels approaching that of the general population, but levels of vaccination for very low-birth-weight infants lag slightly behind.

Health Maintenance Organizations↗
PubMed1999

Necrotizing myopathy induced by overexpression of interferon-gamma in transgenic mice.

A transgenic mouse model has been established in which the cytokine interferon-gamma (IFN-gamma) is overexpressed through the action of the acetylcholine receptor epsilon promoter acting at the neuromuscular junction. While originally developed as a model for the study of the pathogenesis of myasthenia gravis, there are important differences from both human myasthenia gravis and its animal model, experimental autoimmune myasthenia gravis. By 4 months of age there was a well-established inflammatory, predominantly necrotizing myopathy, with marked dystrophic calcification. Dystrophic and degenerative changes in terminal axons and adjacent Schwann cells were also apparent. The acetylcholine receptor was not the primary target of the inflammatory response, since at 10 weeks of age the receptor content was not decreased and antibodies were not detected bound to the receptor. The IFNgamma transgenic mouse model may provide a clinically relevant model of necrotizing myopathy for investigation of the pathological changes associated with, and presumably precipitated by, overexpression of the pro-inflammatory cytokine interferon-gamma on the neuromuscular junction, intramuscular nerves and myofibers.

Animals↗
PubMed1999

Pancreatic expression of keratinocyte growth factor leads to differentiation of islet hepatocytes and proliferation of duct cells.

Keratinocyte growth factor, (KGF), a member of the fibroblast growth factor (FGF) family, is involved in wound healing. It also promotes the differentiation of many epithelial tissues and proliferation of epithelial cells as well as pancreatic duct cells. Additionally, many members of the highly homologous FGF family (including KGF), influence both growth and cellular morphology in the developing embryo. We have previously observed elevated levels of KGF in our interferon-gamma transgenic mouse model of pancreatic regeneration. To understand the role of KGF in pancreatic differentiation, we generated insulin promoter-regulated KGF transgenic mice. Remarkably, we have found that ectopic KGF expression resulted in the emergence of hepatocytes within the islets of Langerhans in the pancreas. Additionally, significant intra-islet duct cell proliferation in the pancreata of transgenic KGF mice was observed. The unexpected appearance of hepatocytes and proliferation of intra-islet duct cells in the pancreata of these mice evidently stemmed directly from local exposure to KGF.

Aging↗
PubMed1999

Unmodified supported thiol/lipid bilayers: studies of structural disorder and conducting mechanism by cyclic voltammetry and AC impedance.

Supported thiol/lipid bilayer assembly, one of the most spectacular bilayer systems in recent years, has provided a good model to study biomembranes because of its high mechanical stability. In this work, the structural and conducting property of unmodified Au supported octadecanethiol/phosphatidylcholine bilayers were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The forming process of bilayer was monitored by capacitance plane plot. The normalized membrane capacitance of supported bilayer is 0.52 microF cm(-2). Kinetically controlled voltammograms determined by Butler-Volmer equation were obtained for both thiol monolayer and thiol/lipid bilayer in linear sweep voltammetry. Results of EIS experiment indicate that collapsed sites and pinhole defects exist in thiol monolayer and lipid monolayer, respectively. The difference between the values of experimental and theoretical standard electron transfer rate constant indicates that the conducting mechanism of Au supported thiol monolayer is electron tunneling at collapsed sites. The conducting mechanism of Au supported thiol/lipid bilayer is attributed as the following: the electroactive species could diffuse through pinholes in the lipid monolayer and reach collapsed sites in thiol monolayer, where electron transfer occurs via a tunneling process. The fractional coverage of the lipid monolayer measure by EIS experiments is about 0.98 or higher.

Electrochemistry↗
PubMed1999

Transgenic expression of epidermal growth factor and keratinocyte growth factor in beta-cells results in substantial morphological changes.

The upregulation of a limited number of growth factors in our interferon-gamma transgenic model for regeneration within the pancreas lead us to propose that these factors are important during pancreatic regeneration. In this study, we have assessed the influence of two growth factors within the pancreas, epidermal growth factor (EGF) and keratinocyte growth factor (KGF), by ectopically expressing these proteins under the control of the human insulin promoter in transgenic mice. This beta-cell-targeted expression of either EGF or KGF resulted in significant morphological changes, including cellular proliferation and disorganized islet growth. Intercrossing the individual Ins-EGF and Ins-KGF transgenic mice resulted in more profound changes in pancreatic morphology including proliferation of pancreatic cells and extensive intra-islet fibrosis. Insulin-producing beta-cells were found in some of the ducts of older Ins-EGF and Ins-EGFxKGF transgenic mice, and amylase-producing cells were observed within the islet structures of the double transgenic mice. These data suggest that both EGF and KGF are capable of affecting pancreatic differentiation and growth, and that co-expression of these molecules in islets has a more substantial impact on the pancreas than does expression of either growth factor alone.

Animals↗
PubMed1999

[Iridoid glycosides from Pedicula dicora Franch].

OBJECTIVE: To study the components in the root of Pedicula dicora. METHODS: Column chromatography with silica gel and polyamide was employed for the isolation and purification of ingredients. The structures were elucidated by spectral method. RESULT: Three iridoid glycosides were obtained and elucidated as mussaenoside, shanzhiside methyl ester and lamalbid. CONCLUSION: All the three compounds were separated from P. dicora for the first time.

Glucosides↗
PubMed1998

[Incorporation of cortical allograft: a biomechanical study].

OBJECTIVE: To explore the changes of biomechanical properties of cortical allograft in different mechanical environments. METHOD: Cortical allograft was transplanted to each side of the midshaft diaphyseal ulnar of 40 rabbits. The left transplanted allograft underwent normal physiological load, while the right underwent lower load. Animals were killed and specimens taken for examination of bone mineral density, bone porosity and maximal three-point-bend breaking load. RESULT: The union strength of allograft-host bone junction increased constantly, while the internal creeping substitution led to an initial greater weakening of the cortical allograft itself and the later recovery of its strength. In comparison, the union strength of the normally loaded graft-host surface was significantly higher than that of the lower loaded side at eight and sixteen weeks after transplantation. At the sixteenth week, there was greater bone strength in normally loaded graft than that in less loaded graft. CONCLUSION: The internal repair would lead to initial greater weakening of cortical allograft and the later gradual recovery of its strength. The effect of physiological load can accelerate the improvement of the biomechanical properties of allograft.

Animals↗
PubMed1998

[Protective effects of Ginkgo biloba extract on focal cerebral ischemia and thrombogenesis of carotid artery in rats].

Rat focal cerebral ischemia induced by occlusion and thrombogenesis of middle cerebral artery(MCAO) was used as experimental model to study the effects of extract of Ginkgo biloba (EGb) and the positive control drugs were urokinase and nimodipine on cerebral infarct size and neurological deficits. The results showed that cerebral ischemia and neurological deficits appeared in rat focal cerebral ischemic models, and the degree was of cerebral ischemia larger in occlusion model than in thrombogenesis model. The cerebral infarct size was significantly smaller and neurological deficits greatly improved at large dose of EGb(200 mg.kg-1, i.v.), the preventive effect appeared to be better than the treatment effect. The positive control drugs urokinase and nimodipine were also shown to distinctly decrease the cerebral infarct size and improve the neurological deficits in the models. Small dose of EGb(100 mg.kg-1, i.v.) was found to decrease the cerebral infarct size of thrombogenesis model, and improve neurological deficits of both thrombogenesis and occlusion model. EGb was also shown to inhibit the thrombogensis of rat common carotid artery stimulated by electrical current in dose-dependent manner. This experiment indicates that EGb might have beneficial effects on prevention and treatment of ischemic stroke and thrombogenesis.

Animals↗
PubMed1998

[Vitrectomy for the treatment of retinal detachment uncomplicated by advanced proliferative vistreoretinopathy].

PURPOSE: To determine the role of vitrectomy be used in retinal detachment uncomplicated by proliferative vitreoretinopathy (PVR). METHODS: We studied 54 cases who had undergone vitrectomy for retinal detachment uncomplicated by severe proliferative vitreoretinopathy. The indications for vitrectomy fell into three main groups: 1) retineal detachment of PVR-B (n = 15), 2) Retinal breaks at the posterior of PVR-C1 or C2 (n = 11), 3) retinal view was poor (n = 28). RESULTS: The success rate with one procedure was 74% and with further surgery retinal reattachment was achieved in 96%. After surgery, the visual acuity was improved in 43 eyes (79.6%) unchanged in 9 eyes (16.7%), and worse in 2 eyes (3.7%). CONCLUSION: Vitrectomy is an effective method for treatment of selected cases of retinal detachment uncomplicated by proliferative vitreoretinopathy.

Adolescent↗