The advantages and disadvantages of traditional method and "PBL"(Problem-Based Learning) in Basic Medicine education are analyzed.Based on the analysis above,a new method which possesses the advantages and discards the disadvantages is introduced to adapt to the education in Basic Medicine in China and will be applied to the laboratory education.

Objective To study the effect of hyperbaric oxygen (HBO) therapy on changes in the prolifera-tion of endogenous neural stem ceils (NSCs) in neonatal rats after hypoxie ischemic brain damage (HIBD). Meth-ods A total of 150 Sprague-Dawley rats aged 7 d were randomly divided into a normal eontrol group ( CON ), a HIBD group and a HBO treatment group. HBO was administered to the HBO treatment group within 3 h after HIBD at 2 atmospheres, once daily for 7 d. The HIBD model rats were subjected to unilateral carotid artery ligation followed by 2 h of hypoxia (8% O2> ). BrdU/nestin immunofluorescence was used to examine the proliferation of NSCs dynami-cally in the subventricular zone (SVZ) and the dentate gyms (DG) at the 3rd h, 21st h, 3rd d, 7th d and 14th d af-ter HBO therapy. Nestin protein was detected by Western blot analysis at various time points after HIBD. Results In the HIBD rats treated with HBO, proliferation of endogenous NSCs was observed in the SVZ and DG. The prolifer-ating NSCs increased at the 3rd h and 21st h after HBO therapy in the SVZ and DG respectively, peaked at the 7th d after HBO therapy, and decreased by the 14th d after HBO therapy, though their level was still higher than that in the controls. The Western blot analysis showed that nestin protein began to increase at the 21st h after HBO therapy, peaked at the 7th d after HBO therapy, then decreased. Conclusion HBO administered within 3 h after HIBD can promote proliferation of endogenous NSCs in neonatal rats after HIBD.

BACKGROUND:The discovery and concept of pulp tissue-derived stem cells is beneficial to the understanding of tooth development and regeneration and repair mechanisms from the cellular level. OBJECTIVE:To understand the induced differentiation capacity and induced conditions in vitro of human dental pulp stem cells into neuron-like cells. METHODS:Pulp tissue was separated from human healthy third molars. Single cellsuspensions were prepared and seeded into 6-wel plates containing alpha-modified minimum essential medium supplemented with 15%fetal bovine serum. Subconfluent cultures (first passage) of colony forming cells were induced with butylhydroxy anisole, forskolin,β-mercaptoethanol, basic fibroblast growth factor. RESULTS AND CONCLUSION:Immunofluorescence and reverse transcription-PCR assay showed that human dental pulp stem cells positively expressed stro-1, Col-I, dentin sialoprotein after 2 weeks of induction. Nestin and neuron-specific enolase were strongly expressed, but the gingival fibroblasts were negatively expressed. It indicates that adult stem cells in human dental pulp have a high neuron-like celldifferentiation potential under a certain inductive condition.

Objective:To establish a method for determining three residual organic solvents in nimodipine liposomes. Methods:The samples were injected into a DB-624 capillary column (30 m × 0. 32 nm,1. 8 μm) by a headspace sampler and analyzed with an FID detector, the carrier gas was nitrogen, the injector temperature was 250℃, and the detector temperature was 250℃. The column temperature was programmed raised. Results:Three residual solvents, namely ethanol, acetone and acetic ether were completely sepa-rated. There was a good linearity within the experimental concentration range. The average recovery was 98. 9%,98. 5% and 99. 4%(RSD=0. 32%,1. 12%,0. 76%,n=9), respectively. The detection limits was 0. 20, 0. 18 and 0. 22μg·ml-1, respectively . Con-clusion:The method is rapid, sensitive and accurate. It can be used in the determination of residual organic solvents in nimodipine li-posomes.

Objective: To examine the effect of dietary behaviors on handgrip strength loss among the elderly, so as to provide insights into the prevention of handgrip strength loss. Methods : Based on the health surveillance cohort among the elderly in Zhejiang Province, two villages or communities were randomly sampled from each of Shaoxing and Zhoushan cities using a multi-stage cluster sampling method, and all residents that had lived in local areas for one year and longer and had an age of 60 years and older were enrolled. Participants' demographics, dietary behaviors, smoking, drinking, and exercise were collected through questionnaire surveys, and the height, body weight and handgrip strength were measured. The handgrip strength loss was diagnosed according the 2019 Consensus Update on Sarcopenia Diagnosis and Treatment proposed by Asian Working Group for Sarcopenia, and the effect of dietary behaviors on handgrip strength loss was examined using a multivariable logistic regression model. Results: A total of 1 265 residents were enrolled, with a mean age of (70.67±7.30) years, and including 565 men (44.66%) and 700 women (55.34%). The overall prevalence of handgrip strength loss was 42.85% among the participants, and the prevalence was 40.35% in men and 44.86% in women, respectively. Multivariable logistic regression analysis showed that nut intake for 1 to 3 times a week (OR=0.180, 95%CI: 0.088-0.367) and for 4 to 6 times a week (OR=0.241, 95%CI: 0.113-0.514) led to a reduced risk of handgrip strength loss among the elderly, and intake of sugary drinks for 4 to 6 times a week led to an increased risk of handgrip strength loss among the elderly (OR=2.298, 95%CI: 1.120-4.714) after adjustment for age, body mass index, educational level and exercise. Conclusion Intake of nuts and sugary drinks may affect the development of handgrip strength loss among the elderly.

Objective: To analyze the clinical and genetic features of progressive cavitating leukoencephalopathy (PCL). Method: The data of clinical and genetic features of 4 PCL patients diagnosed by Beijing Children′s Hospital between January 2015 and January 2016 were analyzed. The cases with complete clinical data retrieved on literature search at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and PubMed (up to August 2016) by using search terms of"NDUFV1" ,"NDUFS1" , or"leukoencephalopathy" , were summarized. Result: There were three females and one male, two of which were compatriots. The age of onset ranged from 6 months to 15 months. All four children′s first symptoms were motor development regression, and the developmental milestones were almost normal before the onset. Of the 4 patients, 3 had cognitive impairment, 1 had seizures, 4 had dystonia and pyramidal impairment, 2 had emaciation, and 1 had nystagmus. The lactate concentrations of 4 patients were normal in blood. One patient had lactaciduria in the urinary organic acid analysis. Cranial magnetic resonance imaging (MRI) of all patients showed leukoencephalopathy, involved in the corpus callosum, and three patients accompanied by cystic lesions. Follow up for 2-13 years showed that the physical and language development were improved. Genetic analysis revealed that mutations in NDUFS1 were found in three patients and NDUFV1 mutation was found in one patient. All six mutations (p.Arg377Cys and p. Arg377His in NDUFV1; p. Arg482Glyfs^*5, p.Thr368Pro, p.Tyr454X and p. Asp565Gly in NDUFS1) are novel. Five English case reports including 10 PCL patients were collected. Together with this group of 4 cases, a total of 14 cases were involved. All 14 children patients had motor development regression, 11 cases had cognitive impairment and dystonia, 6 cases had pyramidal impairment, 5 cases had irritability, 4 cases had epilepsy and nystagmus, 3 cases had strabismus and swallowing difficulty. Cranial MRI showed patchy leukoencephalopathy with cavities, involved in the corpus callosum. Follow up for 19 months-15 years that the neurology development were improved slowly in all patients. Conclusion NDUFS1 and NDUFV1 gene mutation screening should be performed firstly in patients with PCL clinical and imaging feature.

Objective: To explore the prevalence of sexting among secondary vocational school students and to examine the correlation between sexting and mental health, so as to provide evidence for prevention and intervention on adolescents mental health. Methods: In April 2021, three secondary vocational schools from central urban area, outskirts and outer suburbs in Shanghai, among 1 580 students were selected by cluster sampling. Results: The proportions of students who received and who forwarded others private photos or videos were 11.96% and 2.78%, respectively. The proportion of students who sent others personal photos or videos was 2.54%. And the proportions of boys were higher than those of girls ( χ 2=45.89, 24.09, 6.66, P <0.01). The results of multivariable Logistic analysis showed that compared with those who had never sexted, students who had ever had any sexting were at higher risk of anxiety ( OR=2.40, 95%CI =1.59-3.61), depression( OR=1.86, 95%CI =1.25-2.75), non suicidal self injury intention ( OR=2.34, 95%CI =1.48-3.69) and suicidal intention ( OR=2.96, 95%CI =1.83-4.79)( P < 0.05 ). Conclusion There is a significant correlation between sexting and mental health among secondary vocational school students. The latent risks of sexting should be included in the curriculum of comprehensive sex education for teenagers to enhance their media literacy and decision making capability, so as to prevent sexual assault or abuse caused by sexting and promote sexual and reproductive health and as well as mental health of adolescents.

Objective: To preliminarily investigate the difference of position fixation accuracy between polyurethane styrofoam and vacuum negative pressure pad in intensity-modulated radiation therapy (IMRT) after radical mastectomy for breast cancer. Methods: Forty breast cancer patients, who received breast-conserving surgery followed by hyper-fractionated IMRT of the whole breast (42.56 Gy for 16 times) in our hospital between 2017 and 2018 were recruited and randomly divided into the polyurethane styrofoam group and vacuum negative pressure pad group. Before IMRT treatment, the anterior and lateral films of patients were taken with kilovoltage digital radiographs (KVDRs) by Varian Trilogy machine-borne OBI KV image verification system. The KVDRs images were matched with the DRR images reconstructed by the planned system to obtain the setup errors in the left and right, head and foot, and ventral and back directions between two groups. Each patient was verified for 10 times to obtain 400 sets of data. The independent sample t-test was adopted to analyze the setup errors between two groups. The external expansion value of graded setup errors from clinical target volume (CTV) and planned target volume (PTV) was calculated. Results: The setup errors in the left and right, head and foot, ventral and back directions between the styrofoam fixation and vacuum pad groups were (1.63±1.29) mm and (1.83 ±1.61) mm (P=0.18), (1.46±1.51) mm and (2.26±2.03) mm (P=0.00), and (1.30±1.35) mm and (1.91±1.67) mm (P=0.00), respectively. The external expansion values of setup errors from CTV to PTV were 2.19 mm, 2.51 mm, 1.57 mm and 2.40 mm, 3.97 mm and 2.63 mm, respectively. Conclusion Both two fixation methods meet the clinical requirements. However, the setup accuracy and reproducibility in the polyurethane styrofoam group are better than those in the vacuum negative pressure pad group.

Objective To investigate the difference of styrofoam and breast carrier in postposition fixation of intensity-modulated radiotherapy after breast conservative surgery for breast cancer patients.Methods From February 2018 to August 2018,tweenty-four patients with breast cancer in Sun Yet-Sen Memorial Hospital of Sun Yet-sen University were selected for this study,who underwent hypofactionationed radiotherapy after breast conservative surgery with total dose 42.56 Gy/16Fractions.They were randomized into styrofoam test group and breastcarrier control group.Cone beam CT as used to record the positioning error under the directions of left and right (x),head and foot (y),abdomen and back (y) within two groups at the first,third,fifth,seventh,eleventh time before irradiation.Furthermore,the PTV extension margin was calculated and the positioning time of two groups was recorded.Two sets of pendulum errors were analyzed by independent sample T-test,and the outspread value of inter-fractional set up error of the PTV was calculated.Results The errors of the test group and the control group in the direction of x,y,z were as follows:(2.36±1.89) and (2.56±2.05) mm (P=0.49),(1.76± 1.78) and (3.28±2.79) mm (P＜0.05),(1.47± 1.49) and (1.73± 1.81) mm (P=0.28).The extension values of inter-fractional set up error of CTV to PTV were 2.97,2.92,2.21 mm and 3.41,4.09,2.59 mm respectively.The time of single positioning was (3.4± 1.1) and (5.5 ± 3.1) min respectively (P=0.01).Conclusion Styrofoam has better positioning accuracy and efficiency compared with breast carrier.

Objective To establish a HPLC method for determination of related substances of risedronate sodium tab‐lets .Methods The C18 column ,5 μm ,150 mm × 4 .6 mm ,the buffer solution (3 .22 g tetrabutyl ammonium bromide was added to a buffer solution of 1 000 ml 0 .05 mol/L ammonium chloride ,then adjusted pH to 7 .8 ± 0 .05 by ammonia)‐methanol‐aceto‐nitrile =250:50:25 as mobile phase ,column temperature:room temperature ,flow rate:1 .0 ml/min ,detection length:254 nm . Results Determined by HPLC at high temperature ,acid ,alkali degradation ,the main peak and the impurity peaks were separa‐ted well ,and the peaks had a linear relationship ,Y=1 .28 × 107 X-1 .62 × 105 (r=0 .999 9) .Conclusion The method was rap‐id ,simple ,accurate and sensitive ,and suitable for determination of risedronate sodium tablets related substances .