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Biomedical subjects

D Yan

Publications and source records attributed to D Yan.

At least 109 records · Page 6Linked to original sources
PubMed1994

Foot shock-induced changes in blood and brain serotonin and related substances in rats.

The effects of electric foot shock on peripheral and central serotonergic systems in rats have been studied. We have focused on the time course alterations with particular attention being paid to changes in 5-HT, 5-HIAA, tryptophan concentrations and 5-HIAA/5-HT ratios in blood and various parts of the brain, observed within 1 h following stress application. Blood and brain (7 regions) samples were taken immediately after electric foot shock, 30 min, 1 and 24 h later. In the blood stress induced a rise in tryptophan level as well as rises in 5-HT, 5-HIAA levels and 5-HIAA/5-HT ratio within 1 h following stressful treatment. Tryptophan concentration was found to be increased in every part of the brain within 1 h after electric foot shock application. In striatum it remained higher even after 24 h. 5-HT level showed a significant rise only in medulla, while hypothalamus was the sole region where a fall in 5-HT was found. In other parts of the brain 5-HT level remained unaffected by stress. 5-HIAA content increased in almost every brain area studied except cerebellum and striatum. 5-HIAA/5-HT ratios shared the same pattern of changes. Briefly, foot shock altered 5-HT turnover in various brain regions, in particular within the first hour following stress application, whereas delayed response to stress was rarely observed. Increased brain tryptophan level seems to be necessary to cope with the enhanced 5-HT metabolism caused by stress, reflecting as a rise in 5-HIAA concentration and 5-HIAA/5-HT ratio.

Animals↗
PubMed1994

[The effect of medical treatment on hypertension community control--a follow-up study of more than one thousand hypertensives in East City Proper, Beijing].

Hypertension exerts a great threat on human health. Although most of countries promote the management of hypertension in communities, the role of treatment of hypertension is still controversial, it directly influences the strategy of hypertension community control. This study was based on the survey of essential and borderline hypertension in Gu-lou District of East City Proper, Beijing in 1981, and the management of 1339 hypertensives in the follow-up from 1982 to 1985, and the mortality registration in the district by Disease Surveillance System. By observing the prognosis within one year among different treatment groups (nonusers, less than 9 months and more than 9 months within one year), 1289 patients were followed up for a total of 4283 person-years. Crude analyses, stratified and logistic analyses with multi-variables adjustment of age, sex, blood pressure, with or without end-organ damage, etc. could not find that treatments had obvious effects on the reduction of incidence and mortality of stroke, mortality of CVD and all-cause in hypertensives except severe cases. The stratified analyses dy smoking also showed that smoking had a disadvantageous effects for treated hypertensives. Based on our results, we suggest that health education should be a major part of hypertension management program in community; treatments of hypertension should consider the flexible situation of patients and may not be a priority in hypertension community control program.

Aged↗
PubMed1993

An evaluation of two methods of anatomical alignment of radiotherapy portal images.

PURPOSE: Two techniques have been developed at our institution to allow anatomical registration of digitized portal images to a simulation film. Accuracy of the portal image alignment methods is tested and single intrauser and multiple interuser variation is examined using each technique. METHODS AND MATERIALS: Method one requires the identification of anatomical fiducial points on a simulation image and its corresponding portal image. The parameters required to align the corresponding points are calculated by a least squares fit algorithm. Method two uses an anatomical template generated from the simulation image and superimposing it upon a portal image. The template is then adjusted by a computer mouse to obtain the best subjective anatomical fit on the portal image. Megavoltage portal images of a skull phantom with various known shifts and eight clinical image files were aligned by each method. Each data set was aligned several times by both a single user and multiple users. RESULTS: Alignment of the anatomical phantom portal images demonstrates an accuracy of less than 0.8 +/- 0.9 mm and 0.7 +/- 1.0 degrees with either method. As out of plane rotation increased from 0 to 5 degrees, simulating out of plane malpositioning, alignment orthogonal to the plane of rotation worsened to 1.5 +/- 1.1 mm with the point method and 2.4 +/- 1.6 mm with the template method. Alignment parallel to the axis of the gantry rotation was insensitive to this change and remained constant as did the rotational alignment parameters. For the clinical image files the magnitude of variation for a single user is typically less than +/- 1 mm or +/- 1 degree. The magnitude of variation of alignment increased when multiple users aligned the same image files. The variation was dependent upon anatomical site and to a lesser degree the method of alignment used. The root mean square deviation of translational shifts range from +/- 0.68 mm when using the template method in the pelvis to as high as +/- 2.94 mm with the template method to align abdominal portal images. In the thorax and pelvis translational alignments along the horizontal axis were more precise than along the vertical axis. Multiple user variability was in part due to poor image quality, user experience, non rigidity of the anatomical features, and the difficulty in locating an exact point on a continuous anatomical structure. CONCLUSION: In well controlled phantom studies both the fiducial point and template method provide similar and adequate results. The phantom studies show that alignment error and variance increase with distortion in anatomical features secondary to out of plane rotations. In clinical situations intrauser variation is small, however, multiple interuser variation is larger. The magnitude of variation is dependent upon the anatomical site aligned.

Computer Simulation↗
PubMed1993

The use of on-line image verification to estimate the variation in radiation therapy dose delivery.

PURPOSE: On-line radiotherapy imaging systems provide data that allow us to study the geometric nature of treatment variation. It is more clinically relevant to examine the resultant dosimetric variation. In this work, daily beam position as recorded by the on-line images is used to recalculate the treatment plan to show the effect geometric variation has on dose. METHODS AND MATERIALS: Daily 6 MV or 18 MV x-ray portal images were acquired using a fiberoptic on-line imaging system for 12 patients with cancers in the head and neck, thoracic, and pelvic regions. Each daily on-line portal image was aligned with the prescription simulation image using a template of anatomical structures defined on the latter. The outline of the actual block position was then superimposed on the prescription image. Daily block positions were cumulated to give a summary image represented by the block overlap isofrequency distribution. The summary data were used to analyze the amount of genometric variation relative to the prescription boundary on a histogram distribution plot. Treatment plans were recalculated by considering each aligned portal image as an individual beam. RESULTS: On-Line Image Verification (OLIV) data can differentiate between systematic and random errors in a course of daily radiation therapy. The data emphasize that the type and magnitude of patient set-up errors are unique for individual patients and different clinical situations. Head and neck sites had the least random variation (average 0-100% block overlap isofrequency distribution width = 7 mm) compared to thoracic (average 0-100% block overlap isofrequency distribution width = 12 mm) or pelvic sites (average 0-100% block overlap isofrequency distribution width = 14 mm). When treatment delivery is analyzed case by case, systematic as well as random errors are represented. When the data are pooled by anatomical site, individuality of variations is lost and variation appears random. Recalculated plans demonstrated dosimetric deviations from the original plans. The differences between the two dosimetric distributions were emphasized using a technique of plan subtraction. This allowed quick identification of relative "hot and cold spots" in the recalculated plans. The magnitude and clinical significance of dosimetric variation was unique for each patient. CONCLUSIONS: OLIV data are used to study geometric uncertainties because of the unique nature for individual patients. Dose recalculation is helpful to illustrate the dosimetric consequences of set-up errors.

Humans↗
PubMed1993

Dissociation of alpha 2-plasmin-inhibitor-plasmin complex and regeneration of plasmin activity by SDS treatment.

In order to understand the mechanism for the complex between alpha 2-plasmin-inhibitor (alpha 2-PI) and plasmin to express its specific activity on fibrin autography after SDS-PAGE, we analyzed the effects of SDS on alpha 2-PI molecule and alpha 2-PI-plasmin complex. Treatment of alpha 2-PI by SDS at the concentrations of 0.01% and 0.1% abolished the activity of alpha 2-PI to form a stoichiometric complex with plasmin, whereas it did not interfere with plasmin's activity. More interestingly, in the case of 0.01% SDS, alpha 2-PI was further cleaved to a smaller molecule. Treatment of previously formed alpha 2-PI-plasmin complex by SDS at the concentrations of both 0.01% and 0.1% dissociated the complex and expressed specific amidolytic activity against tripeptide substrate (S-2251), which activity was totally quenched by aprotinin. When alpha 2-PI-plasmin complex was treated by higher concentration of SDS for 12 hours, dissociated free plasmin's band could be observed on SDS-PAGE analysis. It is likely, therefore, that the exposure of alpha 2-PI-plasmin complex to SDS during the procedure of SDS-PAGE dissociates the complex and expresses its specific proteolytic activity in fibrin autography. These features of alpha 2-PI and its complex with plasmin are similar to those of plasminogen activator inhibitor type 1 (PAI-1) and its complex with plasminogen activators (PAs), thus they may represent some common features of the SERPINS.

Antifibrinolytic Agents↗
PubMed1993

Correlation between serotonergic measures in cerebrospinal fluid and blood of subhuman primate.

The relationship between the concentration of serotonin (5-hydroxytryptamine; 5-HT), its precursor; tryptophan (Trp) and the main metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) and blood of monkey have been studied. 5-HT, Trp and 5-HIAA underwent circadian changes in both CSF and blood. Significant correlations were found between 5-HT, 5-HIAA and Trp in CSF and blood. The significance of these findings and their relationship to the use of peripheral serotonergic system as a functional model of the central nervous system are discussed.

Animals↗
PubMed1993

Serotonergic measures in blood and brain and their correlations in rats treated with tranylcypromine, a monoamine oxidase inhibitor.

Tranylcypromine, a monoamine oxidase inhibitor, was administered to male Wistar rats in order to investigate its effects on blood and brain serotonin related substances after 1, 4, and 24 h following injection and possible relations between serotonergic measures in central nervous system and periphery. The dose of the drug tested was responsible for an increase in blood serotonin with a simultaneous fall in its metabolite 5-hydroxyindoleacetic acid (5-HIAA) compared to either pretreatment or control values. These changes were the most marked after 4 and 24 h following tranylcypromine injection. Almost all brain areas studied (cerebellum, medulla, hypothalamus, striatum, midbrain, hippocampus, and cortex) were to be affected by monoamine oxidase inhibitor treatment. They exhibited a rise in serotonin content starting from 1 h after drug administration and lasted in many parts of the brain up to 24 h, which was accompanied by a parallel fall in 5-HIAA level. All these changes were significant when compared to baseline and control values. Alterations in blood serotonin correlated positively with changes in brain serotonin and negatively with brain 5-HIAA, while the opposite pattern of correlations was found regarding blood 5-HIAA and the content of serotonin and 5-HIAA in various brain areas studied. This pattern of correlations speaks in favor of an existence of mutual relations between blood and brain serotonin related substances. Our results suggest that blood serotonin and 5-HIAA may serve as an index of monoamine oxidase inhibitor action on the central serotonergic system.

Animals↗
PubMed1993

Interleukin-2-responsive wound-infiltrating lymphocytes in surgical adjuvant cancer immunotherapy.

Wound-infiltrating lymphocytes (WIL) were assessed in murine models of localized sarcoma and carcinoma to evaluate the role of interleukin-2 (IL-2)-responsive lymphocytes in adjuvant immunotherapy. Following tumor resection, IL-2 or diluent was injected at the surgical site for 6 days. Surgical site tissues were harvested and digested in a triple enzyme mixture, and single cell suspensions were prepared. Thy 1.2+ lymphocytes were isolated by incubating cells with monoclonal anti-Thy 1.2 antibody-coated magnetic beads. Lymphocyte-bead complexes were extracted with a magnet and cultured in medium containing IL-2 (100 units/ml) for 1-3 weeks. Perioperative IL-2 immunotherapy led to a three- to four-fold increase in WIL yield. WIL from IL-2-treated mice also demonstrated enhanced cytolysis of the autologous tumor and bound to activated endothelial cells with greater avidity than did the controls. We conclude that perioperative IL-2 therapy augments the yield, as well as the cytolytic and adhesive properties, of wound-infiltrating lymphocytes.

Animals↗
PubMed1992

Relationship between serotonergic measures in periphery and the brain of mouse.

Circadian rhythm and the relationship between the concentration of serotonin (5HT) and related substances (5-hydroxyindoleacetic acid; 5HIAA and tryptophan; Trp) in mouse brain, stomach and blood have been studied. All factors underwent circadian changes in the brain and blood. 5HT and 5HIAA levels in the stomach showed no circadian fluctuation. The concentrations of 5HT in the brain and blood did not correlate. Significant correlations were found between other serotonergic parameters analyzed in brain, stomach and blood. A significant negative correlation was observed between brain 5HIAA and blood 5HIAA. The concentration of tryptophan in the brain was correlated with the plasma total tryptophan level. There was fairly significant correlation (p less than 0.06) between brain serotonin and plasma tryptophan levels. The brain serotonin and tryptophan levels were strongly correlated (R = 0.410, p less than 0.03). Significant negative correlation was found between serotonin in the blood and serotonin in the stomach as well as between its level in the brain and in the stomach. The significance of these findings and their relationship to the use of peripheral serotonergic system as a model of neurons are discussed.

Animals↗
PubMed1992

[Primary analysis on hypertension community control in East City].

In order to carry out chronic disease prevention, a hypertension community control program has been conducted in Disease Surveillance Point, East City. Beijing since 1989. The resident committees were randomly divided into two groups. The community control activities were conducted in intervention group, which included home visit, health education. 3190 hypertensive cases were managed in 1991. Current smoking rate was decreased 8.37%, quit and reduce smoking increased 5.81%, drinking decreased 8.77%, reduced salt intake 5.45%, DBP < 95 mmHg increased 27.81%, when compared with base line survey in 1989. These indicators were significant between intervention and control groups. It means hypertension community control program is successful.

China↗
PubMed1990

Marek's disease virus gene clones encoding virus-specific phosphorylated polypeptides and serological characterization of fusion proteins.

Marek's disease virus (MDV) gene clones, RA2 and GA8, constructed in E. coli bacteriophage lambda-gt11 (gt11) were identified by a monoclonal antibody (MAb), H19.47, against a putative transformation-related viral antigen consisting of a complex of three phosphorylated polypeptides, pp41, pp38, and pp24. Both recombinants have a MDV-DNA insert of about 0.5 kb and are mapped to the region of BamHI-H or EcoRI-X fragments of the MDV genome by Southern blot hybridization. Immunoblot and immunoprecipitation with H19.47 identified a recombinant beta-galactosidase-MDV 140-kD fusion protein for RA2 and a 127-kD fusion protein for GA8. Immunoprecipitation of 35S-methionine-labeled, MDV-infected chicken embryo fibroblasts (CEF) with antisera against RA2 and GA8 fusion proteins recognized five polypeptides, of which three (p41, p38, and p24) are specified by H19.47 and the remaining two, p135 and p20, have not been previously identified. Immunoprecipitation of 32P-phosphate-labeled or 3H-glucosamine-labeled, GA-MDV-infected CEF with the antiserum against RA2 fusion protein identified a phosphorylated polypeptide of 38 kD and two glycoproteins of 60 and 49 kD, respectively. The antisera against recombinant fusion proteins thus revealed the existence of epitopes common to the phosphorylated polypeptides and other MDV-specific polypeptides. Sera from chickens or mice hyperimmunized with the purified fusion proteins reacted with serotype 1, MDV-infected CEF in the fluorescent antibody (FA) test to significant titers. These immune sera did not react with either serotype II or III, indicating the serotype specificity of the phosphorylated polypeptides.

Animals↗