Dihydrofolate reductase (DHFR), a housekeeping enzyme in primary metabolism, has been extensively studied as a model of acid-base catalysis and a clinic drug target. Herein, we investigated the enzymology of a DHFR-like protein SacH in safracin (SAC) biosynthesis, which reductively inactivates hemiaminal pharmacophore-containing biosynthetic intermediates and antibiotics for self-resistance. Furthermore, based on the crystal structure of SacH-NADPH-SAC-A ternary complexes and mutagenesis, we proposed a catalytic mechanism that is distinct from the previously characterized short-chain dehydrogenases/reductases-mediated inactivation of hemiaminal pharmacophore. These findings expand the functions of DHFR family proteins, reveal that the common reaction can be catalyzed by distinct family of enzymes, and imply the possibility for the discovery of novel antibiotics with hemiaminal pharmacophore.

Objective To explore the current status of the application of health portals in the field of public health, and analyze the factors affecting users' adoption of health portals, so as to provide a theoretical basis for promoting the use of health portals and promoting health management. Methods Referring to domestic and foreign literature, integrating the technology acceptance model and the dual motivation factor theory, a comprehensive analysis framework was built, and the influencing factors of whether various groups of people adopt health portals were analyzed from multiple dimensions. Results The current status of health portal applications around special groups and specific purposes was analyzed. A comprehensive analysis dimension was constructed with perceived usefulness and perceived ease of use as the basic framework, service quality, social norms and users themselves as specific indicators, and positive and negative impacts as specific directions. Conclusion From the perspective of service, society and individuals, analyzing the positive and negative factors that affect users’ adoption of health portals, it is necessary to strengthen the use of health portals by special groups such as the elderly, to further improve disease prevention and control, deepen public health services, and promote the development of healthy China.

Objective To study the cell morphology and differentiation efficiency when rabbit bone marrow mesenchymal stem cells (BMSCs) were induced osteogenic differentiation as culturing by autologous platelet-rich plasma (PRP) instead of serum,and to explore a new method of inducing BMSCs osteogenic differentiation.Methods The PRP was prepared by arterial blood of rabbit.Punctured and The bone marrow was sampled from rabbit's iliac bone,and BMSCs were collected,which divided into PRP group,fetal calf serum (FBS) group and serum-free control group,and cultured in 10％ autologous PRP,10％ FBS and serum-free respectively,combined with DMEM-F12 medium.The second generation cells were divided into experimental and control groups.The experimental groups' medium was added dexamethasone,β-sodium glycerophosphate and ascorbic acid,and the control groups went on.The cell morphological difference of each group was Observed between anterior and after inducing differentiation,and compared between each group.Results BMSCs of PRP and FBS groups grew quickly,presented like fusiform form before induction,and increasd in volume,became a triangle,polygonal and round form gradually after osteogenic induction.Cells of PRP and FBS groups aggregated spontaneously and multilayered,and formed calcium nodules and bone-like structure after induced 7 days averagely,which could be stained red by alizarin red S;cells of serum-free groups were induced 14 days averagely,only three samples showed osteogenesis performance.Cells of PRP and FBS groups differentiation efficiency was superior to serum-free groups when inducd 20 days,the difference was statistically significant (P＜0.05),and the difference between efficiency of PRP and FBS groups was not significant (P＞0.05).Conclusions Autologous PRP could be used to proliferate and induce osteogenic differentiation of BMSCs instead of serum.

Objective To compare the efficacy of ultrasound-guided lumbar epidural access using paramedian transverse scanning (PMTS) versus paramedian saggital scanning (PMSS) with the needle inplane.Methods Fifty American Society of Anesthesiologists physical status Ⅰ-Ⅲ patients,aged 50-75 yr,weighing 55-85 kg,undergoing lower extremity surgery under combined spinal-epidural anesthesia,were divided into PMSS group (n=25) and PMTS group (n=25) using a random number table.The realtime ultrasound-guided lumbar epidural access (L3,4) was performed using PMTS and PMSS in PMTS and PMSS groups,respectively.The visibility of ligamentum flavum,posterior and anterior dura maters,posterior epidural space on the prepuncture ultrasound images,imaging quality score,time for puncture and depth of puncture were recorded.The development of air ultrasonic contrast sign and backflow of cerebrospinal fluid from the spinal needle were recorded.The development of adverse reactions such as paresthesia and hypokinesia was also recorded on 2 days after operation.Results Compared with group PMSS,the time for puncture was significantly shortened,the depth of puncture was shallower (P＜0.05),and no significant change was found in the visibility of spinal structure,imaging quality score or air ultrasonic contrast sign and incidence of backflow of cerebrospinal fluid in group PMTS (P＞0.05).No significant change was found in adverse reactions such as paresthesia or hypokinesia between the two groups (P＞0.05).Conclusion PMTS provides clear imaging and simple and convenient operation in guiding lumbar epidural access with the needle in-plane when compared with PMSS,and it is worthy of clinical application.

Objective To explore the operating methods and its related questions of auricular reconstruction with totally expanded skin in combination with laser hair removal for the treatment of adolescent microtia.Methods From Jan.2013 to Dec.2016,30 adolescent microtia patients were treated with totally expanded skin.At the first stage,the 100 ml kidney-shaped expander was implanted under the skin of mastoid.After expanding capacity of 80 ml,the hair on the expanded skin was depilated once a month with reference to the healthy ear;at the second stage,after expanding capacity of 150 ml,the expander was taken out and the fiber capsule was removed;the tautologous rib cartilage was harvested and the scaffolds were sculptured;the cartilage was implanted and the expanded skin flap was used to cover the frontal surface and back surface of the scaffold;at the third stage,the earlobe transposition,conchal excavation and tragus construction were performed at the same time.Results All the patients were followed up for 3 to 24 months;the results showed 1 case of leakage of expander,4 cases of hematoma,2 case of expanded skin burst,and the complications were treated correctly,all patients were satisfied with the appearance;the color,texture,location,size;and height of ear cranial angle were matched with health ear;there was no obvious scar and auricle subunit structure was clear.Conclusions The laser in combination with the large capacity tissue expander in auricular reconstruction is simple,less trauma and less scarring.

Objective To observe the clinical efficacy of propranolol and 595 nm pulsed dye la ser (PDL) in treatment of infantile hemangioma.Methods 26 infants admitted to our hospital from January 2013 to January 2015 with hemangioma underwent oral propranolol 2 mg/(kg · d) treatment after excluding of taboos.The daily doses were divided equally to two parts,taken on the time of 8:00 and 20:00,when the electrocardiograph and pulse oxygen were monitored and recorded persistently.The patients were discharged from the hospital when it was stable,with review of blood routine examination,fasting blood glucose,liver and kidney function,and the change of size,character and color of hemangioma were recorded,and taken photos every two weeks after discharge.The 595 nm PDL was used to treat the hemangioma faded incompletely when the propranolol was terminated.Results The tension and color of all hemangioma decreased in varying degrees in taking propranolol for 72 hours,and evaluated the efficacy as recovery completely 19 cases;signifivantly effective in 3 cases and partial efficacy in 4 cases;the latter 7 cases were further treated with 595 nm PDL.Followed-up for 6-12 months showed that efficacy of recovery reached 100％.10 cases showed heart rate was mild reversibly slow,with no special treatment.5 cases had diarrhea,and healed with symptomatic treatment.No adverse reactions like liver and kidney dysfunction and so on were found.Conclusions Propranolol and 595 nm PDL can effectively treat infantile hemangioma,and thus it can be used as the recommended treatment of infantile hemangioma.

Objective To evaluate the changes in the expression of neuroligin1 in excitatory postsynaptic membrane of the spinal dorsal horn in a rat model of inc isional pain.Methods Forty-eight pathogen-free healthy adult male Sprague-Dawley rats,aged 6-8 weeks,weighing 280-320 g,were divided into control group (group C,n =12) and incisional pain group (group Ⅰ,n=36) using a random number table.A1 cm long incision was made in the plantar surface of the right hindpaw in group Ⅰ.Cumulative pain score (CPS) was assessed and mechanical paw withdrawal threshold to von Frey stimuli was measured at 3 hand 1 and 3 days after operation (T1,2,3).The animals were then sacrificed and their lumbar segments (L3-6) of the spinal cord were removed for detection of the expression of neuroligin1,postsynaptic density-95 protein (PSD-95),glutamate receptor 1 (GluR1) and GluR2 in the postsynaptic membrane of spinal dorsal horn (by Western blot) and co-expression of neuroligin1 with PSD-95 in spinal dorsal horn (by co-immuno-precipitation).Results Compared with group C,CPS was significantly increased and mechanical paw withdrawal threshold was decreased at T1-3,and the expression of neuroligin1 and GluR1 in the postsynaptic membrane of spinal dorsal horn at T1,2 and co-expression of neuroligin1 with PSD-95 at T1 were up-regulated in group Ⅰ (P＜0.01 or 0.05).Conclusion The development and maintenance of incisional pain is related to the signaling pathway regulated by neuroligin1 in excitatory postsynaptic membrane of the spinal dorsal horn of rats.

Objective:To investigate the prevalence of chronic obstructive pulmonary disease (COPD) in the adults aged 40 years old and over in Changchun urban area,and to clarify the important significance of early application of pulmonary function examination.Methods:With the help of community workers,10 communities which around Second Hospital of Jilin University were selected and the participants aged 40 years old and over were randomly collected.COPD questionnaire and pulmonary function examination were conducted in all subjects.The patients with COPD were diagnosed according to the criteria established by the Global Initiative for COPD (GOLD).The patients with COPD were divided into the diagnostic group and undiagnostic group,then the patients with COPD who had smoking history were divided into smoking cessation group and smoking group.The pulmonary function of each groups were compared.Results:A total of 1 392 participants aged 40 years old and over were recruited in this survey,including 568 males and 824 females,and their average age was (59.59±6.60) years.Totally 176 subjects were diagnosed as COPD,and the prevalence was 12.64％.Furthermore,160 of them were newly diagnosed,which showed the undiagnostic rate of COPD was 90.91 ％.Among the 176 patients with COPD,16 had been confirmed before,which meant only 9.09％ patients got the accurate diagnose before.The analysis of high-risk factor (smoking) showed that the population had an increased prevalence of COPD (20.71％) compared with non-smokers (8.8％) (P＜ 0.05).The correlational analysis between smoking index and the pulmonary function of the patients with COPD showed that all of the pulmonary function indexes except forced vital capacity (FVC％) and maximum midexpiratory flow (MMEF％) in smoking cessation group were descended along with the increase of smoking index (P＜0.05).All of the pulmonary function indexes except FVC％ in smoking group were descended along with the increase of smoking index (P ＜ 0.05).Conclusion:The high prevalence and underdiagnostic rate of COPD are found in the residents aged 40 years old and over in Changchun urban area.More patients with COPD should be screened by performing pulmonary function examination to treat them at an early stage.

Objective To evaluate the clinical efficacy of “Shamrock” ultrasound images?guided lumbar sympathetic ganglion blockade ( LSGB) . Methods Sixty patients of both sexes, aged 18-60 yr, weighing 50-70 kg, of American Society of Anesthesiologists physical statusⅠorⅡ, undergoing unilater?al LSGB, were divided into groupⅠ ( n=30) and group Ⅱ ( n=30) using a random number table. In group Ⅰ, unilateral LSGB was performed at the L2 level under ultrasound guidance with paramedian trans?verse scanning. In groupⅡ, unilateral LSGB was performed at the L2 level under ultrasound guidance with“Shamrock” ultrasound images. After final needle position was confirmed, 2% lidocaine 6?0 ml was ad?ministered in each patient. At 20 min before and after LSGB, the visual analogue scale scores and skin temperature of the big toe of the affected foot were recorded, and the successful blockade and visibility of important paravertebral structures on ultrasound images were recorded during puncture. Results The visu?al analogue scale scores were significantly lower, and the skin temperature on the affected side was signifi?cantly higher after LSGB than before LSGB in both groups ( P<0?05) . The important paravertebral struc?tures such as erector spinae, quadratus lumborum, psoas major, transverse process of L2 vertebrae, and the curved edge of L2 vertebrae were visible in both groups. The visibility rate of the inferior vena cava or ab?dominal aorta on ultrasound images and the success rate of blockade were significantly lower in group Ⅰthan in group Ⅱ (P<0?01). Conclusion Compared with paramedian transverse scanning, LSGB has some advantages such as real?time monitoring, higher success rate of blockade, better efficacy and avoiding damage to great vessels when performed under “Shamrock” ultrasound image guidance.

BACKGROUND:Early vascularization is crucial for wound healing. A high-porosity, macrovoid alogeneic skin leads to the rapid vascularization and celular infiltration.
OBJECTIVE: To obtain a new alogeneic skin product with high porosity, good cel permeability and good histocompatibility using an improved preparation method of human acelular dermal matrix.
METHODS: Cel components of healthy human skins were removed by the improved method and the traditional method, respectively. The improved method was to remove the subcutaneous fat, eliminate the epidermis (1 mol/L NaCl solution at 37℃ for 24 hours) folowed by shaking processing (2% NaOH at 45℃ for 4 hours), and then, the solution was neutralized with PBS rinsing, dried and stored at 4℃ for standby. We detected the porosity and degradation time in vitroof the acelular dermal matrices prepared by two methods and the cytotoxicity of the material infiltration liquid on the adipose-derived stem cels. Hematoxylin-eosin staining was used for the detection of the cel residual, the integrity of colagen and cel biocompatibility. Scanning electron microscopy was used to detect the pore size.
RESULTS AND CONCLUSION: Both the two methods could completely remove the cel components, and maintain the integrity of the colagen scaffold. The porosity of acelular dermal matrix with the improved method was (93.22±0.99)%, which was significantly higher than that with the traditional method [(74.28±2.06)%;P < 0.001]. However, there was no significant difference in in vitrodegradation time between the two kinds of acelular dermal matrices(P > 0.05). No obvious cytotoxicity of the acelular dermal matrix prepared with the improved method was detected. At 3-7 days of co-culture, the adipose-derived stem cels cultured on the acelular dermal matrix prepared with the improved method could penetrate the basement membrane to the deep dermis, while there was no obvious cel invasion and growth in the deep dermis prepared by the traditional method. Compared with the traditional method, the improved method is more suitable for cel infiltration and growth with higher porosity and larger pore size.