Objective To survey on present situation of medical students' study style and to provide references to improve the development of study style. Methods Totally 512 undergraduate stu-dents of one medical university in Tianjing were asked to fill the questionnaire by themselves. Main con-tents of the questionnaire included study targets,study attitudes,study methods,teaching level,teaching equipments,school training system and management system,etc. Epidata3.02 was used to accomplish data entry and SPSS software was used to do statistical analysis. The data were described by percentage. Results More than 50.0% students took attending post-graduate examination,passing college English test band 4 and band 6 and getting diploma as main study purposes. 81.96%(404/499)medical stu-dents spent their spare time on study by themselves. 98.40%(491/499)students took notes in class,while only 8.62%(43/499)students often discussed questions with their teachers after class. 70.54%students said that they ever attended academic lectures organized by college and achieved benefits from them. 40.88%(204/499)students were highly eager to win scholarship. More than half of the students took gloomy atti-tude towards getting a job and this phenomenon should cause educators' attention. 78.56%(392/499 ) students held the opinion that medical professional teachers have higher teaching level and 26.65%(133/499 ) students thought that college's teaching equipments should be improved . Conclusions Following aspects should be emphasized in order to further strengthen and improve medical students' study style:making further efforts to arouse students' study initiative,playing the leading role of teach-ers and promoting study style by promoting teaching style,improving rules and regulations of study style development and strengthening college's hardware construction.

Highly Active Anti-Retroviral Therapy (HAART) has effectively inhibited the prevalence of HIV-1 and reduced the death rate caused by AIDS. In recent years,the emergence of resistance-conferring RT gene mutations in HIV-1 strains has become the major reason for HAART failure. The detection of drug resistance is important for the HAART regimen choice and novel drug development. A novel assay for the detection of HIV-1 RT drug resistance mutations was developed. HIV-1 drug resistance and wild strains in B subtypes were investigated using Two-Step Mutagenically-Separated PCR (MS-PCR),and point mutations including M41L,K70R,K103N,Y181C,T215F were detected. A longer mutant type primer was designed,using microplates hybridization and ELISA technique to detect several point mutations within a mixed mutant-wild type population. The results indicate that the Two-Step MS-PCR is as sensitive and specific as that in the traditional MS-PCR and MS-PCR combined with ELISA can give a good P/N quotient with better sensitivity,low cost,relatively less time consumption and high-throughput screening. It will be used in clinic usage for the detection of HIV-1 drug resistance mutations as well as other point mutations.

HIV-1 envelope glycoprotein gp41,which is a hopeful target for HIV-1 fusion inhibitors,plays a critical role in the fusion of viral and cellular membranes.In order to build up the screening assay of HIV-1 fusion inhibitors targeting gp41,HIV-1 gp41 5-helix and 6-helix were expressed in prokaryotic cells.Gp41 5-helix and 6-helix recombined plasmids were constructed by using PCR,enzyme digestion and ligation taking the clade B HIV-1 genome as a template.The plasmid was transferred into E.coli BL21(DE3)and then induced by IPTG.The expressed protein was purified by affinity chromatography after denaturation and renaturation.The SDS-PAGE analysis was used during expression and purification.Native-PAGE was used to identify the interaction between gp41 5-helix and T-20.The result will be helpful to build up the screening assay of HIV-1 fusion inhibitors targeting gp41.

Objective To detect the sperm apoptosis rate and level of reactive oxygen species (ROS) in seminal plasma and explore their correlation among infertile males. Methods Ninety-two inferitile males were divided into varicocele (VC) group (n=32), leukocytospermia group(n=30) and the other cause group (n=30), and another 24 in vitro fertilization sperm samples were sereved as controls. The routine sperm parameters including seminal pH, sperm viability and sperm density were examined by computer assisted sperm analysis, the sperm apoptosis rate was asseseed using Annexin V/PI staining, and the ROS level in seminal plasma was detected by TBA method. The differences in seminal parameters between three infertile groups and control group were compared, and the correlation of sperm apoptosis rate with level of ROS in seminal plasma was explored in each group. Results The sperm viability of three infertile groups was significantly lower than that of control group (P<0.01). The sperm apoptosis rates and levels of ROS in seminal plasma in VC group and leukocytospermia group were significantly higher than those in control group (P < 0.05 or P < 0.01). The sperm apoptosis rate was positively correlated with the level of ROS in seminal plasma in leukocytospermia group(r=0. 573, P < 0.05). Conclusion The increased sperm apoptosis rate and level of seminal plasma ROS may be related to the infertility of patients with VC and leukocytospermia. The increased level of seminal plasma ROS may be one of the causes of increased sperm apoptosis rate in patients with leukocytospermia.

Objective To study the expression level of thyroid insulin-like growth factor-Ⅰ (IGF-Ⅰ) in iodine deficiency and excess mice and the effect of thyroid gland IGF-Ⅰ in the thyroid morphological change. Methods Forty-eight Balb/c mice were chosen as studied objects,weighing about 16 g. They were divided into three groups: low iodine(LI,iodine content of 50 μg/kg in feed,drinking deironized water) group,normoi(NI,iodine content of 300 μg/kg in feed,drinking deironized water) group and high(HI,iodine content of 300 μg/kg in feed,iodoine of content 14 700 μg/kg in drinking) group,16 mice in each group. Mice were put to death after 12 weeks and taken out of their thyroid gland. The body weight,absolute and relative weights of thyroid gland were measured and the morphological change of thyroid gland were observed under microscope. The expression levels of thyroid gland IGF-Ⅰ mRNA and protein were detected by RT-PCR and immunohistochemistry,respectively. Results There were statistical significances between groups of thyroid absolute and relative weights(F = 315.881,405.921,all P < 0.01). LI group [(10.71±4.03) mg,(44.98±15.39)mg/100 g body weight]and HI group [(3.42±1.17)mg,(13.50± 3.89)mg/100 g body weight]had heavier thyroid absolute and relative weights than NI group[(2.11±0.53)mg,(8.35±1.98)mg/100 g body weight,all P < 0.01]. Under microscopy,the thyroid follicle capacity grew down and the follicle quantity grew up in LI group,the epithelium was stylolitic,the colloid diminished or absence in follicular cavity,while HI group presented colloid accumulation without follicular hyperplasia. The expression level of thyroid gland IGF-Ⅰ mRNA in LI group(1.03±0.32) was more than that in NI(0.65±0.19) and HI(0.59± 0.20) groups(F= 7.518,P< 0.01). In contrast to NI,there was no difference in the expression level of thyroid gland IGF-Ⅰ mRNA in HI group(P > 0.05). The brownish particles of LI group were more than NI and HI groups in the thyroid follicle epithelium by immunohistochemistry,while HI group was less than NI group. Conclusions The mice of iodine deficiency presented follicular hyperplasia goiter,the mice of iodine excess presented colloid accumulative goiter. The change of IGF-Ⅰ mRNA and protein expression may participate morphologleal change,indicating autocrine IGF-Ⅰ of thyroid gland may play an important role in regulating goiter formation.

Objective To study the effects of different level of iodine nutrition on the thyroid function in women of reproductive age. Methods A total of 100 (50 from each) women of reproductive age but not pregnant were collected from iodine deficient and adequate areas. The questionnaire was obtained individually with items concerning personal history of thyroid diseases, goiters and category of edible salt and drinking water based on the project design. The household salt and drinking water were collected for measuring iodine content, and blood samples were obtained for TSH, FT4 and FT3 testing. Results The coverage of iodized salt and the median level of urinary iodine in iodine deficient women(72.0% and 95.5 μg/L) were obviously lower than that in iodine sufficient women(100.0% and 167.4 μg/L, χ2=16.28, U = 632.00, P < 0.01). Median level of serum TSH in iodine deficient women (2.56 m U/L) appeared in an increasing tendency compared to the iodine sufficient women (1.88 mU/L), but there was no significance (U=990.50, P > 0.05). Serum FT4 mean level in iodine deficient women [(14.7±2.0) pmol/L]was lower than that in iodine sufficient women[(17.0±3.8)pmoI/L, t=3.76, P<0.01]. There was no difference in serum FT3 between two group women[(5.1±1.4), (4.8±0.5)pmoI/L, t = 1.59, P > 0.05]; but FT3/FT4 ratio in iodine deficient women(0.33±0.04) was markedly higher than that in the iodine sufficient women(0.30±0.04, t=3.13, P<0.01). The percentage of thyroid dysfunction in iodine deficient women[20.0% (10/50)]was higher compared with the iodine sufficient women[8.0%(4/50)], but without significance(χ2=2.99, P>0.05). Conclusions Iodine deficiency is a primary cause leading to hypothyroid in women of reproductive age. Long term of iodized salt usage is an efficient way to correct iodine deficiency.

Laparoscopy-assisted distal gastrectomy (LADG) is a minimally invasive surgical technique, and also an important development of modern surgery. According to Japanese Gastric Cancer Treatment Guideline, indications of LADG must be strictly limited in early gastric cancer patients, while it should be investigated in advanced gastric cancer. Based on available studies, the short-term advantage of LADG for early gastric cancer has been generally accepted, but the totally laparoscopic technique for early gastric cancer is still to be further studied. LADG for advanced gastric cancer continues to be controversial, which needs the relevant final results of randomized controlled trials from China, Japanese, and Korean to determine, although some current studies have demonstrated similar efficacy of LADG plus D2 lymphadenectomy as compared to open gastrectomy.
Adenocarcinoma ; Gastrectomy ; methods ; Humans ; Laparoscopy ; Lymph Node Excision ; Stomach Neoplasms ; surgery

Electromagnetic Fields ; Magnetic Fields ; Microwaves ; adverse effects ; Television

The pol gene of HIV-1 encodes mainly three enzymes: reverse transcriptase (RT), protease (PR) and integrase (IN). Currently, FDA approved drugs targeting RT and PR are available and administered in various combinations, while no anti-IN drug was approved. HIV-1 integrase is an essential enzyme for the viral replication and an interesting target for the design of new pharmaceuticals for multi-drug therapy of AIDS. The 288 amino acids of IN (32kDa) recognizes specific sequences in the long terminal repeats (LTRs) of the retroviral DNA. The IN protein catalyzes the 3′-processing step and the 5′-strand transfer step reaction in vivo, which was called integration and this reaction could be analysed by ELISA Assay in vitro. It has been reported that F185K and C280S mutations of HIV-1 integrase would improve the enzyme solubility, and the catalytical activity of the enzyme was the same as that of the wild-type enzyme in vitro. In order to build the platform of screening inhibitor against integrase of HIV-1 virus, the IN enzyme was expressed and the function of integrase protein was assayed. The cDNA of clade B HIV-1 genome was used as a template, overlapped PCR was used to construct site mutagenesis of F185K/C280S and NdeI/Xho I restriction sites were brought in. The PCR product was cloned into the prokaryotic vector pET-28a(+) to form a recombined plasmid, transferred into the host cell E.coli(BL21 DE3). The recombined clones were identified by PCR and Nde I/Xho I digestion .The positive plasmid was sequenced, and the successfully recombined plasmid in the host cell was induced by IPTG. The expressed IN protein was puriied sy the Co+ affinity chromatography column and SDS-PAGE was used to analyze the molecular weight and specificity. In addition, ELISA assay was used to analyze the function of the recombined IN protein. The recombinant protein was soluble, and expressed highly and stably in E.coli. The molecular weight of the expression product was identical to the expectation. The IN protein was proved to be functional in 3′ processing and 5′strand transfer by ELISA. It will be helpful to build the platform of screening inhibitors against HIV-1 integrase.

0.05).There was significant difference in the 3-year survival rate between A and C group. Conclusions The 3-year survival rate was dramatically increased with combined therapy mainly by cisplatin, the dose of 60～80mg is tolerant for the elderly aged above seventy years, and perioperation complications can be cured.