Alzheimer’ s disease ( AD) is one of the most common dementia of neurodegenerative disorders, which results from the deposition of amyloid-beta ( Aβ) and there are no curative treatments for this disease at present.It had been proved that prion protein is the receptor for Aβand it plays a key role in the progress of AD with dual-side effects. Prion protein can not only transfer neurotoxicity to neurons but also protect them from neurotoxicity of Aβ.The polymor-phisms of prion protein encoding gene ( PRNP) affect the AD incubation period and clinical symptoms in humans and other animals.The discovery of PRNP mutational mouse fills the gaps of existing AD mouse models in this research area, which is potential for the studies of pathogenesis, new drugs design and testing aspects.The role and effects of prion protein in AD pathogenesis were summarized in this paper, furthermore, the discovery and utility of PRNP gene mutational mouse in research on AD and/or amyloid diseases were reviewed, and in order to provide some guidance for AD animal model study.

BACKGROUND:Calcium citrate has a better solubility than calcium phosphate, calcium sulfate, and other calcium biomaterials. The synthetic calcium citrate has a good denseness, and stably releases calcium ions at a high efficiency during the degradation. Consequently, it may be more suitable for the fil ing of fracture defects, providing needed calcium ions for early fracture healing.
OBJECTIVE:To prepare calcium citrate biomaterials with a novel formulation based on the natural bio-mineralized oyster shel s and citric acid so as to expect to get a good application in fracture healing repair.
METHODS:Crushing, grinding, and chemical reaction methods were used for refinement. Particle size analyzer, X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy were adopted for analysis of the size distribution, composition, mineral phases, and micro-morphology. Biological characteristics were evaluated through a simulated body fluid experiment.
RESULTS AND CONCLUSION:Oyster shel powder was reacted with saturated citric acid to produce the calcium citrate material that had uniform crystal structure and compact bonding among crystal bodies, and exhibited a certain mechanical ability. The calcium citrate material had a good crystal structure that was conductive to prolong the degradation time. The calcium citrate released calcium ions slowly, and did not produce dramatic changes in the pH value (7.20-7.46) of the surrounding in the dissolution process. With the gradual degradation of calcium citrate materials, Ca2+concentration in solution increased gradual y and stably, and ultimately achieved an appropriate concentration of 7 mmol/L, suitable for osteoblast proliferation and differentiation. Calcium citrate prepared using natural oyster shel has good biological properties, and exhibits a natural superiority to artificial bone materials.

BACKGROUND:Some scholars have prepared zein/chitosan composite membrane based on blending methods, and preliminary evaluation ofitsphysical and chemical properties showsthat chitosan partly improvesthe mechanical properties and hydrophilic properties of zein. Therefore, zein/chitosan composite membrane presumably has good cytocompati bility, which is beneficial to osteogenic differentiation of bone marrow mesenchymal stem cels.
OBJECTIVE:To explore the effect of zein/chitosan composite membrane on the differentiation of bone marrow mesenchymal stem cels into osteoblasts and its feasibility asabone tissue-engineered material.
METHODS:With 60% acetic acid as solvent, zein/chitosan composite membrane was prepared by blending and casting method. The structure and physicochemical properties of the composite membrane were investigated by Fourier transform infrared spectroscopy, tensile testing, water absorption testing and scanning electron microscopy. And the cytocompatibility of the membrane was evaluated byin vitrocel cufture. Besides,bone marrow mesenchymal stem celsfrom Sprague-Dawley ratwere isolatedvia adherence screening method, andthe effects of thecompositemembrane on theosteogenic differentiation ofthese celswere observedby scanning electron microscopy, fluorescent labeling and alkaline phosphatase assay.
RESULTS AND CONCLUSION:The tensile strength, water absorption and hydrophilicity of the films were improved with the chitosan increased; chitosan could promote cel proliferation indicating the good cytocompatibility of the composite films. Moreover, osteogenic induction occurredin bone marrow mesenchymal stem cels cultured on the compositem embrane, and with an increase of chitosan, the induction was promoted. In conclusion, zein/chitosan composite membrane can be applied widely in the field of bone tissue engineering.

0.05).Conclusions These results suggest that the polymorphisms of triplet repeat GGC or combination of CAG and GGC of the androgen receptor is signifi- cantly associated with Han men with androgenetic alopecia in the Eastern China. However, genetic polymor- phism of 5?-reductase may not directly associated with androgenetic alopecia in our study population.

Course teaching for international students in many domestic universities is in English.Some practice and experience of the department of nuclear medicine in Tianjin medical university are introduced from the aspects of teaching course,concerning preparations before class,teaching process and teaching techniques,which will give references to nuclear medicine teaching for international students.

BACKGROUND:With the development of tissue engineering, autologous chondrocyte implantation is often used to repair cartilage defects. And poor integration is one of the common reasons that lead to failure repairing. Many models in vitro are used for related studies.
OBJECTIVE:To develop an interface integrated model of tissue engineered cartilage repair in vitro and to evaluate the effect.
METHODS:Cartilage integration model in vitro was established in pigs. Total y 21 cartilaginous rings were obtained and divided into agarose gel group (n=18) and control group (n=3). In agarose gel group, cartilage rings were covered with agarose gel. Chondrocytes were separated and implanted into the ring. The leakage of cells around the cartilage rings was observed. The sections were stained for histological observation at 1, 2, 4 weeks. The average area of neochondrocytes was measured and compared.
RESULTS AND CONCLUSION:The results from the control group were not processed, because there was no chondrocyte aggregate formation in the center of the explant ring due to earlier chondrocyte leakage outside the explant. While no chondrocytes were found outside the explant ring in the agarose gel group. Tissue sections of the agarose gel group were stained by hematoxylin and eosin, alcian blue, Safranin-O and col agen type II immunohistochemistry at 1, 2, 4 weeks. Neochondrocytes proliferated within cartilage ring, and produced extracellular matrix. After 2 weeks of incubation, these inserted chondrocytes were significantly increased. There was no statistical y significant increment between 2 weeks and 4 weeks (P>0.05), although the area was further increased by 4 weeks. This model provides a convenient simulation of the cartilage integration process in vitro and has a potential application in studies of cartilage integration and cartilage tissue engineering.

Objective: To understand the environmental sanitation situation of rural schools in different geographical areas of Shaanxi, and to provide scientific basis for improving hygiene and sanitation in Chinese rural schools. Methods: Each year during 2016 to 2018, 150 townships in 30 counties of rural areas were randomly selected in various districts and cities throughout the province. In each township one junior high school and one elementary school were randomly selected, and the data was obtained through resource access, interviews, and on-site observations. The data was statistically analyzed and evaluated according to the northern, central and southern regions. Results: The differences of drinking ways among students in the schools were of statistical significance(χ2=25.89,P<0.01). The major drinking water method of students in the monitoring schools of the three regions all was providing boiled water, accounting for 56.16%, 65.88%, 50.39%, all of which have direct drinking unboiled water phenomenon; The water supply method of the self-provided centralized water supply school is mainly precipitation filtration in the central and southern regions, accounting for 38.46%, 53.21%, and untreated in the northern region(60.61%); The differences of the proportions of having sanitary toilets, detached toilets in schools, having toilets in teaching buildings, and having toilets in dormitory buildings in three regions were of statistical significance(χ2=32.04, 12.73, 20.78, 33.11, P<0.01) The proportion of schools with squat toilets in men’s toilets was greater than that of women’s(χ2=86.53, 44.77, 21.88, P<0.01). The differences of the proportion of schools with faucets available in toilets and within 5 meters around toilets, with sinks in or around the toilets, with sinks equipped with soap in or around the toilets were of statistical significance(χ2=90.02, 10.40, 41.96, P<0.01). Conclusion During 2016 to 2018, the environment sanitation of the three major rural primary and middle schools in Shaanxi Province needs to improve corresponding supporting facilities, and increase publicity to improve teachers and students’ awareness of health and safety.

Objective:To investigate the role of mitofusion 2 (Mfn2) in high glucose (HG)-induced endoplasmic reticulum stress (ERS) and apoptosis of podocytes.Methods:(1) Streptozocin was used to induce a diabetes mellitus (DM) rat model. Renal histopathological changes in rats were observed by HE staining. Expression of Mfn2 and CCAAT/enhancer-binding protein homologous protein (CHOP) in glomeruli was observed by immunohistochemistry. Protein levels of Mfn2, protein kinase RNA-like ER kinase (PERK), phospho(p)-PERK, and CHOP in glomeruli were analyzed by Western blotting. (2) Conditionally immortalized human podocytes (HPC) cultured in vitro were divided into control, mannitol (MA) and HG groups. Expression of Mfn2 was observed by immunofluorescence. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. (3) HPC were divided into control, HG, HG+Mfn2-Myc plasmid-transfected and HG+control plasmid-transfected groups. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Expression of CHOP was observed by immunofluorescence. Mitochondrial membrane potential in each group was observed by mitochondrial membrane potential assay kit with JC-1. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. Results:(1) Compared with the control group, the glomerular mesangial matrix of the DM group rats was significantly proliferated, and the expression of Mfn2 was down-regulated with the expression of ERS-related proteins p-PERK/PERK and CHOP up-regulated (all P<0.05). (2) Compared with the control group, Mfn2 was down-regulated and p-PERK/PERK and CHOP were up-regulated in HPC of HG group (all P<0.05). Apoptosis of HPC was also increased in HG group. There was no significant difference in the above indicators between the control group and the mannitol group (all P>0.05). (3) Compared with the HG group, mitochondrial membrane potential of HPC was alleviated and apoptosis of HPC was decreased in HG+Mfn2-Myc plasmid-transfected group ( P<0.05). P-PERK/PERK and CHOP were down-regulated in HG+Mfn2-Myc plasmid-transfected group (both P<0.05). There was no significant difference in the above indicators between the HG group and the HG+control plasmid-transfected group (all P>0.05). Conclusions:Mfn2 down-regulation in HG-stimulated podocytes may induce ERS to increase apoptosis of podocytes. Up-regulation of Mfn2 can alleviate the HG-induced ERS and apoptosis in podocytes.

Objective: To investigate and analyze the drinking water quality among rural primary and secondary schools in Guanzhong area in 2018, and to provide a basis for the targeted improvement of water supply facilities. Methods: Develop a questionnaire on the basic situation of centralized water supply in rural schools, according to the Standard Test Method for Drinking Water (GB/T 5750—2006) and the Sanitary Standard for Drinking Water (GB 5749—2006) for the rural school network in Guanzhong area. The peripheral water collection and testing carried out single factor and multifactor statistical analysis on the relationship between water quality influencing factors and water quality pass rate. Results: The total qualified rate of drinking water quality in rural schools in Guanzhong area was 59.1%. Univariate analysis showed that water quality rate was affected by four factors including water source type, engineering type, sanitation permit and disinfection equipment use, and the difference was statistically significant(P<0.05). Unconditional two-class logistic regression analysis showed that disinfection (OR=3.14), engineering type (OR=2.05), and sanitation permit (OR=1.99)(P<0.05) affected the water quality pass rate. Conclusion It is recommended to further strengthen the investment in the renovation of water supply for rural schools in Guanzhong area, and specifically strengthen water supply treatment and standard disinfection.

Objective To construct a model of Graves'disease ( GD ) with ( or ) Graves'ophthalmopathy ( GO) in BALB/c mice by immunization with pcDNA3. 1/TSHR289. Methods pcDNA3. 1/TSHR289 was injected into the bilateral gastrocnemius muscle of 35 model mice and electroporation was immediately performed. 10 control mice were injected with sterile saline and electroporated, while 5 blank mice were injected with sterile saline only. Each group of mice was immunized at 1, 4, 7, and 10 weeks, respectively. Serum total T4 , TSH, TSAb, and TSBAb were measured before immunization, 2 weeks after each immunization, as well as 5 and 8 weeks after the last immunization. CT scan was used to evaluate the morphological changes of the eyes of the mice.99m TcO4- imaging was used to measure the thyroid uptake function, and the pathological changes of the thyroid and orbital tissues were evaluated by HE staining. Results After the 2nd time immunization, the serum concentrations of TT4 , TSAb and TSBAb in GD mice were significantly higher than those of control and blank groups( F=13.781, 31.435, 36.112, P<0.01, respectively).The TSH continued to be significantly lower than that of control and blank groups(F=13.966, P<0.01) . After the 4th time immunizations, the ability of uptaking99m TcO4- in GD mice thyroid was significantly enhanced compared with the control group. The thyroid goiter with a large amount of lymphocyte infiltration, and the thyroid follicle was thin. CT scan of GO mice showed thickening and swelling of the extraocular muscles, and no abnormalities in tendon and muscle attachment points. HE staining showed thickening of extraocular muscle fibers, lymphocyte infiltration of extraocular muscles and orbital tissue, increased hyaluronic acid, and infiltration of fat cells. Conclusion GD or GO model can be successfully induced by multiple intramuscular injection of pcDNA3.1/TSHR289 in BALB/c mice.