MR-T1ρ imaging is one of the novelest MRI techniques in recent years,T1ρ relaxation mainly reflect the interaction between water molecules and the surrounding macromolecu]es.Due to the unique point of view,the technique has been used to investigate a variety of pathological mechanisms in early stage of diseases,such as the content of collagen protein in articular cartilage,neuron apoptosis in neurodegenerative diseases and so on,which provides a new tool for detecting lesions in ultra-early stage or the evaluation of treatment effect.

The coadsorption behavior of two complementary DNA bases,adenine(A) and thymine(T),was studied on Au(111) electrode by cyclic voltammetry(CV) and electrochemical scanning tunneling microscopy ( ECSTM) in aqueous solution. From the CVs,the coadsorption behavior of A and T was more closed to the adsorption behavior of A. In the potential range of physisorption,high- resolution ECSTM images of revealed that a new super-structure was formed by the hydrogen bonds between A and T. A molecular model of the super-structure was proposed based on the STM results and the possible hydrogen bonds between A and T.

Objective: Prader-Willi syndrome (PWS) is characterized by severe hypotonia and feeding difficulties in early infancy, followed by excessive eating and gradual development of morbid obesity in later infancy or early childhood. Patients with PWS are often too young to manifest sufficient features or have atypical findings, making genetic testing important to confirm the diagnosis of PWS. Approximately 99% of patients with PWS have a diagnostic abnormality in the parent-specific methylation imprint within the Prader-Willi critical region (PWCR) at chromosome 15q11.2-q12. Of them, 70% have a paternal deletion; 25% have a maternal uniparental disomy (UPD); and <5% have a mutation in the imprinting center. Methods: Current techniques can identify a diagnostic abnormality, such as paternal deletion or maternal UPD for most of patients with PWS, but they are labor-intensive and cost-expensive. Multiplex ligation-dependent probe amplification (MLPA) is a novel, simple, and cost-effective technique for analysis of relative quantification in a single assay, which has recently been applied for the detection of genomic deletions, duplications, and amplifications in a variety of genes. Results: Six out of 20 patients referred for genetic diagnosis of PWS were found to have a deletion by MLPA, confirmed by FISH and DNA methylation analysis with 100% concordance. Conclusion: MLPA's high sensitivity and specificity for deletion detection is the same as FISH or Southern blot based analysis. Additional collaborative effort for developing and validating the complete MLPA-PWS assay, for not only detecting deletion but also identifying methylation abnormality, is on going.

Objective: Spinal muscular atrophy(SMA), an autosomal recessive neuromuscular degeneration of the anterior horn cells of the spinal cord and brain stem, results in one of the most common diseases with muscle fatigue and atrophy. Most SMA cases including all the types are due to the homozygous deletion of at least exon 7 within the survival motor neuron 1 (SMN-1) gene. Although a "golden standard" assay (PCR with mismatch primer followed by enzyme digestion) is very reliable for the identification of homozygous SMN-1 deletion, the carrier detection of heterozygous SMN-1 deletion remains a challenge. Methods: Some PCR-based gene dosage assays or multiplex PCR allow for the determination of the copy number of SMN-1 gene to identify heterozygous deletion, but these procedures are often time consuming and available on a limited clinical basis. Recently developed MLPA (multiplex ligation-dependent probe amplification) is an efficient procedure that can accurately analyze relative quantification to establish the copy number of the SMN gene. We performed a validation for simultaneous detection of homozygous SMN-1 deletions of SMA patients and heterozygous SMN-1 deletions of SMA carriers in a simple assay using a MLPA-SMA assay specific reagent. Results: Six out of 20 patients with SMA were found to have homozygous SMN-1 deletion, confirmed by the PCR/digestion assay. All 4 parents of the children with SMA had heterozygous SMN-1 deletion, confirmed by an independent relative quantitative analysis. Conclusion: MLPA provides a simple, rapid and accurate method of simultaneously detecting homozygous deletions and heterozygous deletions in a single assay for both SMN-1 and SMN-2 genes.

Objective To study the color digital fundus photography of the fundus in the physical examination in screening and clinical importance to guide treatment.Methods 50 245 cases (100 490 eyes) healthy subjects with Topcon TRC NW100 digital color fundus camera to take pictures after the screening analysis.Results The number of the Inspector General,50 245 cases,45 373 cases of normal,accounting for 90.3％,a general description of those 359 cases,accounting for 0.7％,the positive findings in 4513 cases,accounting for 9.0％.Positive comparison between men and women of all age groups showed no significant difference ( P ＞ 0.05 ).Positive findings of retinal arteriosclerosis in the detection rate of 7.4％,0.1％ of the diabetic retinopathy,macular degeneration,0.1％,0.6％ of retinopathy,optic atrophy 0.1％,the optic nerve C/D greater than 0.7％.Screening of the positive findings of the subjects to give timely and accurate diagnosisandtreatmentrecommendations.Conclusion Digitalcolorfundusphotography objectivity,reproducibility andnon-invasive characteristics of the image data to facilitate thestorage and exchange,andretinalmicrovascular disease couldbetter predictthe effects on cardiovascular and cerebrovascularevents,and therefore have important applications in the field ofhealthy value.

Objective To understand the mental health status of healthy young men from 18 districts or counties in Beijing,so as to provide evidence for mental health management.MethodsVolunteers who had participated physical check-ups and got normal results underwent psychological examinations,including computer tests,paper pencil intelligence tests,and structured psychological interviews.Results From 2006 to 2009,a total of 28 386 healthy young men from 18 districts or counties of Beijing completed psychological examinations.The unqualification rate was 2.53%,3.28%,7.56% and 7.52% in year 2006,2007,2008 and 2009,respectively.Conclusion The overall psychological condition of young men living in Beijing may be comparatively better,which might be related to the higher level of psychological education,increased school-entrance rate,better economic condition,higher educational level of parents and improved social and cultural activities.The computer software for psychological test could be stable to some certain extent.

Objective To explore whether differences in high school student health exist between urban and suburban areas in Beijing.Metheds To make comparative analysis on the related data collected from the physical examinations conducted in the 19 districts in Beijing for senior high school admission and college admission in 2007.Results Differences in student health(including height,weight,eyesight)exist between urban and suburban areas in Beijing.There is significant difference in eyesight(t=2.321,P=0.033)between urban and suburban junior school graduates in Beijing.There are significant difierences in height(t=2.617,P=0.018)and the incidence of overweight(t=4.650,P=0.000)between urban and suburban boys junior school graduates.There is significant difference in height(t=3.792,P=0.001)between girls.Conclusions The health condition of high school students is being affected by the overloaded study tasks and unhealthy lifestyle.which needs to be intervened.

BACKGROUND:Gastric cancer mesenchyal stem cel s from clinical stomach cancer specimens and tumorigenic tissues in nude mice are similar to the bone marrow mesenchymal stem cel s in biological characteristics, which have been proved to be an important component of tumor microenvironment to promote tumor growth. It is speculated that biological characteristic of bone marrow mesenchymal stem cel s may change in stomach cancer microenvironment. OBJECTIVE:To observe the effect of stomach cancer microenvironment on morphology and proliferation of bone marrow mesenchymal stem cel s and expressions of CD34 and CD44. METHODS:Rat bone marrow mesenchymal stem cel s were cultured alone as control group. In the test group, rat bone marrow mesenchymal stem cel s were co-cultured with human stomach cancer BGC-823 cel s using Transwel chamber assay to establish the stomach cancer microenvironment. Then, cel morphology, proliferation, cel cycle and CD34, CD44 expressions were observed and detected using inverted phase contrast microscope, MTT assay, and flow cytometry, respectively. RESULTS AND CONCLUSION:In the test group, bone marrow mesenchymal stem cel s were similar to human stomach cancer cel s BGC-823 that arranged disorderly and irregularly, were interconnected loosely, became thinner and longer, and grew in clusters with smal er nuclei. The cel proportion in G 1 phase significantly decreased, but that in S and G 2/M phases significantly increased (P<0.01, P<0.05). The positive rate of CD44 significantly declined, and the CD34 expression significantly raised (P<0.01). In conclusion, stomach cancer microenvironment by non-contact co-culture with BCG-823 cel s has an obvious effect on the morphology, proliferation and surface antigens expressions of bone marrow mesenchymal stem cel s that wil tend to be malignant gastric cancer cel s.

BACKGROUND: Vascular endothelium growth factor (VEGF) is an endothelium mitogen and angiogenic factor with strong potential during recovery from cerebral infarction (CI). Can such therapeutic effect be detected with magnetic resonance diffusion imaging?OBJECTIVE: To study the therapeutic efficacy of VEGF plasmid in treating focal cerebral infarction in a dog experimental model with the aid of diffusion- and hemodynamic-weighted magnetic resonance imaging (MRI),with the morphological results compared with those of immunohistochemical examination.DESIGN: Completely randomized controlled, double blind evaluation,analysis of variance, Pearson correlation analysis, follow-up for 2 weeks.SETTING: Department of Medical Iconography, the Second Affiliated Hospital of Hebei Medical University.MATERIALS: This study was carried out at the Department of Medical Iconography, the Second Affiliated Hospital of Hebei Medical University,between April 2001 and March 2002. Totally 18 healthy adult dogs weighing 10-15 kg were randomly divided into control group and experiment group with half in each.METHODS: All dogs were subjected to femoral intubation and then made into CI model by the occlusion of middle cerebral artery with an embolus injected through the internal carotid artery. Dogs in control group were put to death at postoperative 24 hours, 1 week and 2 weeks with three at each time point, while four dogs in experiment group were put to death at postoperative 1 week and five at 2 weeks. Dogs in experiment group received microinjection of 0.5 mL fluid containing pcD2/hVEGF121 (500-600 μg)instantly after operation, which was replaced with physical saline of the same volume at the same time point in control group. Then they were subjected to MRI scanning once an hour for 4 times, with the sequence of T1WI, T2WI, 3D-TOFMRA, DWI and CET1WI, which was repeated at postoperative 24 hours, 3 days, 1 week and 2 weeks. Based on the MR images, pathological focuses were selected for morphological observation of cells with the aid of HE staining, and CD34 IHC staining was used for counting micrangium, as well as VEGF staining for VEGF positive cells.Then the apparent distribution coefficient (ADC) was calculated, and the differences between different time points and groups were analyzed by analysis of variance. The number of capillaries and VEGF positive cells of each high-power field was counted, with the results compared with those of MR scanning so as to explore the correlation between MR signal changes and IHC results.MAIN OUTCOME MEASURES: ① The number of capillaries and VEGF positive cells in each high-power field was counted at postoperative 24 hours, 1 week and 2 weeks; ② MR images of each group.RESULTS: Data of the 18 dogs entered the final analysis. ① Diffusionweighted imaging (DWI) showed higher signals at infarctional region at postoperative 1 hour, which became strengthened as time went by. ②ADC decreased to (5.61 ±1.39) mm2/s at postoperative 3-4 hours, about 43% lower than that of the opposite hemisphere [(9.85±2.04) mm2/s]. It resumed to (9.83±1.11) mm2/s, but was still lower than the normal level.③ The subsequent MR scanning proved that ADC ratio presented an increasing tendency in contrast with the decreasing tendency at super-acute stage. The increment was even more marked in control group and the difference was significant at postoperative 2 weeks (P=0.032, 0.006). ④ The number of capillary positive cells on the affected side in experiment group was significantly higher than that in control group at postoperative 2 weeks [(28.80±3.29)/field, (20.70±4.47)/field, (P ＜ 0.01)]. ⑤ The number of VEGF positive cells on the affected side in experiment group was significantly higher than that in control group at postoperative 1 and 2weeks [(64.20±9.40)/field, (51.90±5.74)/filed; (72.70±6.98)/filed,(58.40±6.35)/field, (P ＜ 0.01)].⑥ The results of MR scanning and IHC were subjected to correlation analysis and revealed that ADC ratio was closely correlated with the number of capillary positive cells, with Pearson correlation coefficient being 0.679 (P ＜ 0.01). Moreover, the number of capillaries and the number of VEGF positive cells were significantly correlated (r=0.668, P ＜ 0.01).CONCLUSION:Morphological observation and IHC revealed that both the local capillaries and VEGF protein content increased markedly in timedependant manner due to VEGF plasmid gene therapy.Meanwhile,the change of ADC ratio was found to be closely correlated with the number of VEGF positive cells and the number of capillaries.

T,and 916-917 ins G were SLC26A4 mutations unreported hitherto, which may be specific to the Chinese population. CONCLUSION The EVA syndrome is a typical autosomal recessivehereditary disease caused by mutations in SLC26A4 gene. Genetic testing of SLC26A4 is the one of the important diagnostic methods for EVA syndrome.