The active form of vitamin D,1,25-Dihydroxyvitamin D3 \,is a secosteroid hormone that binds to the vitamin D receptor(VDR),a member of the superfamily of nuclear receptors for steroid hormones,thyroid hormone,and retinoic acid.1,25-Dihydroxyvitamin D3 and its analogue regulate calcium and bone metabolism,control cell proliferation and differentiation,and exert immunoregulatory activities.Recent advances in understanding their functions and novel insights into the immunomodulatory mechanisms they control suggest a wider applicability in the treatment of autoimmune diseases and induction of allograft tolerance.In addition to direct effects on T cell activation,1,25-Dihydroxyvitamin D3 and its analogue modulate with different mechanisms the phenotype and function of antigen-presenting cells(APC),and,in particular,of dendritic cells(DC).In vitro and in vivo experiments have shown that 1,25-Dihydroxyvitamin D3 and its analogue induce DC to acquire tolerogenic properties that favor the induction of regulatory rather than effector T cells.These intriguing actions of 1,25-Dihydroxyvitamin D3 and its nanlogue have been demonstrated in several experimental models and could be exploited,in principle,to treat a variety of human autoimmune diseases,or inhibit allograft rejection.

Objective To study the immunomodulative effects of 1,25-Dihydroxyvitamin D_3 1,25-(OH)_2D_3 on the predominant Th1 response rats. Methods Lewis rats had been fed with 1,25-(OH)_2D_3 (1000ng per rat) for 14 days. The rats in control group were administered vehicle with the same volume as the drug to serve as the experimental group, and then LPS (10ng/kg) was administered intraperitoneally in both groups on the 15th day. 15 rats of each group were sacrificed 6h later and immunological index was measured. Mortality of the remaining ten rats in both group have been observed. Results There was no death in experimental group, while five control rats died at 24h (5/10, 50%), and all the other five control rats survived at 96h. IL-12 and IFN-? were decreased significantly in the experiment group compared with control (3986?328pg/ml vs 4160?289pg/ml, P=0.028; 4840?802pg/ml vs 5264?524pg/ml, P=0.020), while IL-4 was increased (5.57?1.75pg/ml vs 3.72?1.62pg/ml, P=0.036). In white pulp of the spleen of experimental rat the number of lymphocytes decreased significantly as shown with HE-staining, and the PCNA positive cells were distributed focally or dispersively. In addition, by using flow cytometer, it was found that CD4~+ CD25~+ positive lymphocytes were increased significantly in the spleen of experimental rats (1.09%?0.29% vs 0.73%?0.00%, P

The convective-diffusive problems of oxygen and carbon dioxide in human airway at normal respiratory status were studied theoretically in the present paper. The human airway was idealized as a bifurcated(two-branch) trachea tree, based on the understanding of the physiological structure of the human airway, and on Horsfield-Wanner optimization analysis about the trachea system status. It was assumed that the gases in the airway were incompressible, viscous fluid, due mainly to the characteristics of the low pressure drop and low rate of the gases within the human airway. One dimensional, non-steady convective-diffusive equations of oxygen and carbon dioxide were solved using Lax-Wendroff finite difference method, i.e., the so called three-legged finite difference method. The boundary conditions were set up according to the two different situations, respectively. The computational results showed the reasonable distributions of the concentration of oxygen and carbon dioxide in the human airway, respectively.
Bronchi ; physiology ; Carbon Dioxide ; metabolism ; Convection ; Diffusion ; Humans ; Models, Biological ; Oxygen ; metabolism ; Trachea ; physiology

Objective To investigate the consistency of the results detected by different types of blood cell analyzer in the blood center .Methods On the basis of the calibration in each analyzer ,with the analyzer obtaining the excellent result in participating the external laboratory quality assessment hosted by the Ministry of Health as the reference ,the fresh blood samples were adopted to analyze other analyzers .Results For the analyzers after conducting the comparison ,the consistency and accuracy of the detection results were ensured .Conclusion After calibration in different types of blood cell analyzer ,the differences exist in the detection re‐sults .Periodically conducting the comparison among different types of instrument has very practical significance .

Objective To investigate the therapeutic efficacy and safety of endoscopic resection of giant gastric stromal tumors without explicit evidence of metastases.Methods A total of 12 giant gastric stromal tumors with no evidence of metastases diagnosed by endoscopic ultrasound (EUS) and computed tomography (CT) scan were managed by endoscopic resection.Operation time,blood loss and the incidence rate of perforation were recorded respectively.The diagnoses of tissue specimens were made by pathological examination and immunohistochemistry.In order to assess local recurrence and distant metastases,endoscopy and endoscopic ultrasound follow-up examinations were performed routinely at 2,6 and 12 months,and the whole abdominal CT scan was also performed at 12 months after operation.Results Endoscopic resections were successfully performed in 10 of 12 cases (83.3％),among which,6 underwent endoscopic submucosal excavation (ESE) without unexpected perforation and 4 endoscopic full-thickness resection (EFR)with intentional perforation.The rate of intentional perforation was 33.3％ (4/12),and all the perforations could be sealed by endoscopic methods.The blood losses were all more than 100 ml,which could be controlled by argon plasma coagulation,electrocoagulation or hemostatic clips.In the 10 encapsulated tumors,8 could be smoothly removed from esophagus,whose long diameter of the minimum cross section was less than 3.5 cm,however,2 tumors whose diameters were larger than 3.5 cm were taken out after segmentation.In the 10 tissue samples,9 were confirmed as low risk GIST,1 larger than 5 cm was pathologically confirmed as high risk GIST.During 1-year follow-up,no local recurrence or peritoneal metastasis was found.2 tumors,larger than 5.0 cm,could not be removed by endoscopic methods due to uncontrolled bleeding.The rate of uncontrolled bleeding was 16.7％ (2/12).The patients were transferred to surgery,and pathologically confirmed as having high risk GIST.Conclusion For low-risk giant gastric stromal tumors whose diameters were less than 5cm without evidence of metastases,endoscopic resection is considered as a safe and effective procedure.Tumors with long diameter of the minimum cross section less than 3.5 cm are more suitable for endoscopic resection,which can be smoothly taken out through cardia.However,for high-risk GIST larger than 5.0 cm,the rate of uncontrolled bleeding is high,so endoscopic resection should be adopted with discretion.

The lungs are naturally irregular and asymmetrical organ in anatomy. The conducting bronchial trees in the lungs display complex self-similar structure. We have established the host mesh coordinates of the right lung on the basis of the anatomical data from the literature. A three-dimensional fractal model of the conducting airways was set up by calculating the coordinates of the mass centers of the divided blocks, searching the branch direction and determining branch lengths with the use of the drawing tool OpenGL. Specific data of the lengths at various grades, branching angles, and capillary diameters were obtained. As a result, the computed data were identical with those of the existing statistical data. The fractal covering dimensionality obtained in the computation of this model was 2.19, which is very close to the ideal dimensionality, 2.17, from the literature. The present model has laid the foundation for further research of the gas diffusion and transfer performance in the lungs using the fractal concept, and furthermore, it helps to save the computer memories and fastening the graphic transfer.
Algorithms ; Bronchi ; anatomy & histology ; Computer Simulation ; Humans ; Imaging, Three-Dimensional ; Models, Anatomic

Based on the principles of the sheet-flow model, oxygen transport in pulmonary capillaries was considered as a process in which oxygen first enters plasma through the respiratory membranes, and then combines with the Hbc. A novel mathematical model about oxygen transport in pulmonary capillaries was established according to the relationship of the oxygen concentration inside the red blood cells with the concentration of haemoglobin and the blood saturation, and according to the basic formula for the correlation between blood saturation and oxygen partial pressure. Furthermore, we adopted the Lax-Wendroff Finite Difference Method and obtained certain valuable results under different physiological states. It was well concluded that the established model could be used to provide useful data for medical researchers as well as doctors.
Biological Transport ; physiology ; Capillaries ; physiology ; Humans ; Models, Biological ; Oxygen ; blood ; Partial Pressure ; Pulmonary Alveoli ; blood supply ; Pulmonary Circulation ; physiology ; Pulmonary Gas Exchange

A three-element model of lumped parameter based on the statistic data of Weible's symmetric model and on the reference anatomic figures of the bronchial tree of the lungs has been proposed using the fluid network theory. It was assumed that the upper five or seven generations of the twenty-four generations of the respiratory airway are asymmetric, while the rest are symmetric. GEAR method was used to solve the ordinary differential equations. The pressure and flow rate distributions in different positions of the lungs during normal respiration and partial bronchial obstruction were compared, respectively. This model has great significance in finding out the air distribution in the human bronchial tree under various physiological and pathological conditions.
Airway Resistance ; Bronchi ; anatomy & histology ; pathology ; physiology ; Humans ; Models, Biological ; Respiration ; Respiratory Mechanics ; physiology

BACKGROUND: Osteoporosis is a genetic disease associated with many enes. To date, the genes that regulate bone mass are incompletely defined.OBJECTIVE: To investigate the relationship between polymorphisms of steoprotegerin (OPG) gene promoter with bone mineral density (BMD) in remenopausal and postmenopausal women.DESIGN: Prospective study.SETTING: Peking Union Medical College Hospital.PARTICIPANTS: In July 2002, 495 Han nationality women selected from Peking Union Medical College Hospital were non-related volunteers and gave their informed consent prior to the study, which included 306 premenopausal women aged 20-39 years, 189 postmenopausal women aged 50-84 years.METHODS: ① BMD measurement: BMD was measured at the Lumbar Spine and Femoral Neck, trochanter, Ward's triangle by dual-energy X-ray absorptiometry. ② Genotyping: Whole blood genome DNA was extracted by QIAGEN DNA extraction kit. The PCR product and the result of endonuclease digest were confirmed by sequencing (Bioasia Biotechnology,Shanghai, China). The impact of the polymorphisms on BMD was also investigated using multiple Logistic regression.MAIN OUTCOME MEASURES: ① Distribution of OPG genotypes and the relationship with BMD. ② Association between OPG polymorphisms and osteoporosis.RESULTS: All 495 subjects were involved in the final analysis. ① These polymorphisms were in Hardy-Weinberg equilibrium (χ2= 0.056 -0.222, P＞ 0.05). The frequencies of genotypes of these subjects were as follows: AA (70.1%), AG (26.9 %), GG (3.0 %) for 163A→G polymorphism; TT (71.3 %), TG (25.9 %), GG (2.8 %) for 245T→G polymorphism. BMD was lower in premenopausal women with GG +AG genotype than AA genotype for 163A→G polymorphism, so did GG+TG genotype than TT genotype for 245T→G polymorphism. But there was no significant difference. BMD was lower in postmenopausal women with AG+GG genotype than AA genotype for 163A→G polymorphism at Lumbar Spine 2-4, Femoral Neck, Ward's triangle and Trochanter (P ＜ 0.05). For 245T→G polymorphism, BMD of postmenopausal women with TG+GG genotype was lower at Femoral Neck,Ward's triangle and Trochanter than TT genotype (P ＜ 0.05). For 245T→G polymorphism, BMD of postmenopausal women with TG+GG genotype was lower at Femoral Neck, Ward's triangle, and Trochanter than TT genotype (P ＜ 0.05). ② Age, weight, height, years since menopause, and 163A→G/245T→G genotypes were sewed as covariates. AG+GG genotype was contributed to low BMD at Lumbar Spine 2-4 and Ward's triangle (OR =2.045, OR=2.956, P ＜ 0.05, 95% CI 1.05-6.7). TG+GG genotype was risk factor for osteoporosis at Lumbar Spine 2-4, Ward's triangle,and Trochanter (OR=2.059, OR=2.859, OR=2.123, P ＜ 0.05, 95% CI 1.04-6.5).CONCLUSION: BMD was lower in postmenopausal women with the variant G allele for 163A→G and 245T→G polymorphisms at Femoral Neck,Ward's triangle, and Trochanter. The variant allele G may associate with lower BMD in postmenopausal women.

BACKGROUND:It is generaly believed that the spine wil be extended, and vertebral muscle atrophy, bone loss of vertebral body, increased height and area of intervertebral disc, changes of composition of intervertebral disc wil occur in the condition of weightlessness. These are likely to be the cause of high incidence of low back pain. OBJECTIVE:To observe changes in lumbar spine bone microstructure analysis of simulated weightlessness on rhesus lumbar spine biomechanics. METHODS:Fourteen young rhesus monkeys were randomly divided into two groups: control group (n=7;free activities in the cage during the experiment), and experimental group (n=7; the use of head-down-10° on a special bed by bundle lying to simulate weightlessness). RESULTS AND CONCLUSION:(1) The results of Micro-CT examination: in the experimental group, structure model index in trabecular bone of increased. Trabecular bone changed from plate-like to the rod-like change. The intersection number of bone tissue in unit length to non-bone tissue declined. The average width of the canal between the trabecular bone increased, suggesting that there have been signs of osteoporosis in the experimental group. (2) Under an optical microscope, in the experimental group, bone hyperplasia line was disordered and irregular. Thick endplate trabecularbone became smal, shalow, and arranged substantialy perpendicular to the direction of trabecular bone and cartilage endplate. The closer the endplate surface, the smaler trabecular bone was. Compared with the control group, these smal trabecular bones were thin and curved. Bone marrow cavity was oval. The degree of the connection between the trabecular bones is poor, reflecting the structural characteristics of significant osteoporosis. (3) It is indicated that weightlessness affected the biomechanical properties of rhesus lumbar motion unit.