D-amino acids were believed to have no function in higher organisms several years ago. Recently, D-serine was proved to be synthesized by astrocytes in vivo and be released to work as an effective coagonist at the “glycine-binding” site of the N-methyl-D-aspartate (NMDA) glutamate receptors in central nervous system. In this paper, the synthesis, metabolism and function of D-serine were reviewed briefly.

Objective To explore the applied value of thyroid imaging reporting and data system (TI-RADS) strati?fication in diagnosing thyroid nodules in patients with different ages.Methods A total of 527 patients with thyroid nod?ules (aged 26-65) were divided into four groups:aged 26-35 group, aged 36-45 group, aged 46-55 group and aged 56-65 group. TI-RADS was used to evaluate patients in four groups. The results of TI-RADS were compared with the pathologic di?agnostic analysis. Results For the low aged groups (aged 26-35 group and aged 36-45 group), the positive predictive val?ue, the negative predictive value and accuracy rate were more than 90%. With regard to the patients aged 46-55, the positive and negative predictive values and accuracy rate were 81.5%, 87.5%, and 81.9%, respectively. The positive and negative predictive values, accuracy rate were 76.6%,88.8%and 77.9%for patients aged 56-65 group. The diagnostic rate of TI-RADS in patients with thyroid lesions was lower in aged 56-65 group than that of other groups. Conclusion TI-RADS method is affected by age. The diagnostic rate is lower in the high age group than that of the low age group.

Objective To study the effects of CBL teaching mode on treatment plan making process among orthodontic postgraduates. Methods Totally 42 junior and senior orthodontic post-graduates were randomly divided into 2 groups (21 per group)named as experimental group and test group. Each group was further divided in to 3 teams involved in CBL and traditional teaching. Six cases of the same type malocclusion were selected each time;after 4 teaching cycle,test scores of two groups were analyzed with SPSS 19.0. Results were shown as mean ± standard deviation and t test andχ2 test were applied to evaluate the rationality and accuracy of treatment plan made by students. Survey questionnaire were issued to teachers and students after class and the assessment results of CBL teaching mode were summed up. Results Test scores were (88.61±8.34)in experimental group and (76.13±8.59)in control group with significant differences (t=3.16,P=0.01). Pass rate of two groups were 96.12%and 87.51%with significant differences (χ2=4.76,P=0.02). During the first teaching program, accurate rates of experimental group and control group were respectively 31.00% and 36.70% and ra-tionality were 33.31%and 33.30%. During the second teaching program,accurate rates of experimen-tal group and control group were 68.80%and 45.70%and rationality were 62.72%and 43.37%. During the third teaching program,accurate rates of experimental group and control group were 89.70% and 51.20%,and rationality were 95.00% and 66.70%. During the fourth program,accurate rates of ex-perimental group and control group were respectively 97.80% and 55.30% and rationality were 98.30% and 75.60%. Conclusions CBL teaching mode is helpful to improve the students' ability of analyzing clinical cases and making more accurate and rational treatment plan,however the increasing teaching cost and the course load are also involved.

Objective To evoke cerebral potentials by stimulating nociceptive fibers with contact heat evoked potentials stimulator (CHEPS)and estimate the nerve conduction velocities of peripheral nerve fibers mediating these responses.Methods Subjects were set in supine position.A heat-foil technology with a rapid rising speed at 70 ℃/s was used to elicit pain and contact heat evoked potentials(CHEP).Contact heat was delivered via one circular thermode (diameter 27 mm,area 573 mm~2).Thermal stimuli were sent at two intensity levels (49.5 ℃ and 54.5 ℃) to three body sites:thenar eminence,the dorsum of hand and proximal volar forarm.Contact heat evoked potentials were recorded from Cz and Pz.A systemic effect between stimulus intensities and pain rating were observed,the main components of this evoked potential were observed.Nerve conduction velocity was calculated from latency difference of CHEP and center to center distance of distal and proximal stimulus arrays.Results The pain intensity rating was 3.2?0.3 and 4.4?0.5 when thenar eminence was stimulated at the temperature of 49.5 ℃ and 54.5 ℃ respectively;the rating was 6.3?0.8 and 7.2?0.5 when the dorsum of hand and proximal volar forarm were stimulated at the temperature of 54.5 ℃ respectively.Three components,Cz/N550,Cz/P750 and Pz/P1000,were found in the evoked potentials.Nerve conduction velocities of the fibers were (12.9?7.5) and (1.7?0.4) m/s respectively,which were corresponding to those of A8 fiber and C fiber.Conclusions CHEPs can be elicited reliably and stably.Velocities of peripheral nerve fibers demonstrate that A8 fiber and C fiber mediate the response.

Objective To establish the method of contact heat evoked potential(CHEP)and to explore the value of this evoked potential in pain testing of patients with cerebral infarction.Methods A total of 100 healthy volunteers and 30 patients were examined.The healthy volunteers were divided into 3 groups according to the length of their arms:(Group A:56.0～65.0 cm ;Group B :65.5～74.0 cm ;Group C :74.5～83.0 cm).A recently de- veloped heat-foil technique with a rapid temperature rising rate at 70℃/s was used to elicit pain and contact heat e- voked potentials.Contact heat was delivered via one circular thermode(diameter 27 mm,area 573 mm~2)and set at two intensity levels(49.5℃and 54.5℃)to three body sites:the thenar eminence,the dorsum of hand and proximal volar forearm.The subjects were asked to rate the pain with numerical rating scale after each stimulus and CHEP was recorded from Cz and Pz.The association between stimulus intensities and pain rating was explored,the main compo- nents of the evuked potential were watched.CHEP,sensory conduction velocity(SCV)and somatosensory evoked potentials(SEP)were performed in patients with hemi-anesthesia caused by cerebral infarction.Results The pain intensity ratings were 3.2?0.3 and 4.4?0.5 at thenar eminence,5.0?0.7 and 6.3?0.8 at the dorsum of hand and 5.3?0.6 and 7.2?0.5 at the proximal volar forearm when the temperature of 49.5℃and 54.5℃was applied, respectively;Three components,Cz/N550,Cz/P750 and Pz/P1000,were identified in the evoked potentials.Cz/ N550 and Cz/P750 appeared when the dorsum of hand and proximal volar forearm were stimulated.In contrast,Pz/ P1000 could be identified when nociceptors of thenar eminence and proximal volar fbrearm were excited.In the pa- tients with cerebral infarction,CHEP disappeared or became abnormal on one side,while SCV and SEP were normal on that side.Conclusion It was suggested that CHEP could be elicited reliably in the controls.CHEP is helpful in the assessment of analgesia in patients with cerebral infarction.

Blood Gas Analysis ; Continuous Positive Airway Pressure ; instrumentation ; Humans ; Infant ; Infant, Newborn ; Pneumonia ; blood ; physiopathology ; therapy ; Respiration

Objective To establish a model to predict the cell-cycle process in response to ionizing radiation.Methods Human choroidal malignant melanoma 92-1 cells were used and the cell cycle distribution of cells was analyzed in 0-96 h after exposure to X-rays.A phenomenological model was constructed based on biological knowledge to describe the cell cycle dynamics in experiments.Results In the present study,a phenomenological model was constructed to describe the cellcycle dynamics of synchronized 92-1 cells in responding to various doses of ionizing radiation.The simulation results obtained with the model were consistent with the experimental data,demonstrating that the model had a good expansibility and could be used to predict the dynamics of cell cycle in responding to ionizing radiation.Further theoretical modeling of the cellcycle dynamics was made and the results were consistent with the simulation.Conclusions A phenomenological model was constructed which could be used to describe the dynamics of cell cycle of cells exposed to ionizing radiation and was supported by the experimental data.Because this model is easy to run by the written code,it has a good expansibility for studying the behaviors of cell populations under various conditions.

Objective To investigate the diagnosis,treatment and prognosis of isolated epidural hematoma (EDH) in children.Methods Clinical data of 83 children,45 males and 38 females (at age of 0.7-14 years),with EDH treated between January 2012 and October 2014 were retrospectively reviewed.Slipping and falling were the most commonly causes of injury.While motor-vehicle accident was noted with increased age.In 16 patients lesion of hematoma was frontal,in 28 patients temporal,in 13 patients parietal,in 9 patients occipital and in 17 patients posterior fossa.Results Of the 28 patients treated surgically,the outcome evaluated using the Glasgow Outcome Score (GOS) was good in 22 patients,mild disability in 2,moderate and severe disability in 1 and death in 3 (one died of venous sinus rupture and one large area infarction).Of the 55 patients treated conservatively,the outcome was good in 52 patients,mild disability in 1,and death in 2 (both presented with bilateral cerebral hernia on admission and one of them was unable to breath spontaneously).Conclusions Overall prognosis of the patients with isolated EDH in children is excellent.Complications of venous sinus rupture,foramen magnum hernia and large area cerebral infarction may contribute to poor prognosis.

Objective To observe a new phosphodiesterase-4 inhibitor Ro 20-1724 on ketamine anesthesia-induced learning and memory impairment and cAMP/PKA-CREB-BDNF signal pathway in immature rats.Methods Twenty-four 21 day-old SD rats were randomly divided into 4 groups (n=6 each):control group (group C) ;ketamine group (group K) ;ketamine+Ro 20-1724 group(group K+Ro) and ketamine+vehicle (0.1％ ethanol) group (group K+E).Ketamine 70 mg/kg was injected intraperitoneally(IP) once a day for 7 consecutive days in groups K,K+Ro,and K+E.Ro 20-1724 0.5 mg/kg and equal volume of vehicle were injected IP at 30 min after IP ketamine each time respectively.Morris water maze was used to assess learning and memory ability after 2 days normal feeding,the escape latency and frequency of passing the platform were recorded.The animals were killed after water maze test and the cAMP,PKA,p-CREB,and BDNF protein expression in hippocampus were detected.Results Repetitive ketamine anesthesia significantly prolonged the escape latency (P＜0.01),decreased the frequency of passing the platform(P＜0.01),and down-regulated the expression of cAMP,PKA,p-CREB,and BDNF protein ((280±31) pmol/mg vs (210± 19) mol/mg,P＜0.01 ; 1.32±0.11 vs 1.13±0.12,P＜0.01 ; 2.61 ±0.22 vs 2.03 ± ±0.19,P＜0.01 ; 1.51 ±0.14 vs 1.16±0.10,P＜0.05) ; Compared with group K,Ro 20-172,significantly attenuated the escape latency time(P＜0.05,P＜0.01)and increased the frequency of passing the platform(P＜0.01),and ameliorated the expression of cAMP,PKA,p-CREB,and BDNF protein ((210± 19) pmoL/mg vs (240± 27) pmol/mg,P ＜0.05;1.13±0.12 vs 1.28±0.12,P＜0.05;2.03±0.19 vs 2.32±0.21,2.32±0.21;1.16±0.10 vs 1.37±0.11,P＜0.01).There was no difference between group K+Ro and group C,and between group K+E and group K(P＞0.05).Conclusion ketamine anesthesia-induced learning and memory impairment can be improved by Ro 20-1724,and cAMP/PKA-CREB-BDNF signal pathway in hippocampus participated in the changes.

AIM: To determine the ultimate preservation time of murine cardiac grafts in 4℃ Ringer's solution. METHODS: Murine cardiac grafts were implanted to the abdominal vessels heterotopically 2, 4, 6, 8 and 10 hours after cold preservation. Graft survival rate and histological morphological changes, as well as the neutrilphil, T cell, macrophage infiltration, ICAM expression were determined by immunohistochemistry. RESULTS: The cardiac function-recovery rate and 1-week graft survival rate were 100% and 83.3% in 6-hour preservation group. Compared with non-preservation control group, no more apparent histological damages, cell infiltration and ICAM expression were found. CONCLUSION: The ultimate preservation time of murine cardiac graft in 4℃ Ringer's solution was 6 hours. [