With the strengthening of nuclear weapon development and the expanding of neutron application in economic area,the injury accidents of neutron radiation are happening from time to time.Neutron exposure,with high linear energy transfer,has high casualty rate,severe symptom and poor prognosis.In comparison with low-LET radiation damage,neutron irradiation induced injuries are more difficult to rescue.This review focused on the recent research progresses of radiation effects,intrinsic mechanisms and clinical prevention measures of neutron radiation,and to provide a theoretical clue for establishing an effective prevention protocol of neutron radiation damage.

BACKGROUND: Pathogenesis and pathophysiological changes of chronic compressive cervical myelopathy havenotbeen completely clarified.OBJECTIVE: To establish an animal model of experimental chronic compressive cervical myelopathy for the exploration of the pathological and electrophysiological changes after chronic spinal compression.DESIGN: A randomized and controlled observatory study using experimental animals as subjects.SETTING: An Animal Experimental Center of a University and an Orthopaedic Laboratory of Affiliated Hospital of a Military Medical University MATERIALS: The study was conducted in the Animal Experimental Center of Nantong Medical University and the Orthopaedic Laboratory of Shanghai Changzheng Hospital from June 2002 to April 2003. Sixty 12-week healthy Chinese rabbits of either gender with a bodymass between 2.5 kg and 3.0 kg were randomly divided into control group( n = 6) and study group( n = 54).METHODS: Titanic metal screw was put into C5 vertebra through cervical anterior approach for progressive compression to establish chronic cervical myelopathy model.MAIN OUTCOME MEASURES:Principal consequences: ①histological examination ;②electrophysiological examination. Secondary consequence:neural function evaluation.RESULTS: Totally 48 rabbits entered into result analysis, in which 6 rabbits from control group and 42 rabbits from study group. Modified Tarlov's motor function evaluation was 3 in 31 rabbits with compression signs, and 4 in 11rabbits without compression signs. The latency of N1 wave in cortical somatosensory evoked potentials (CSEP) was (9.11 ± 1.61 ), ( 11.36 ± 2.17)and (17.55 ± 3.73) ms respectively in animals of control group, animals of study group without compression signs and animals of study group with compression signs. The lantency of CSEP N1 wave was significantly longer in animals of study group with compression signs than that of the animals in the control group and study group without compression signs (P＜0.05).CONCLUSION: This animal model can simulate clinical invasion process of chronic compressive cervical myelopathy. The severer the spinal compression is, the more often the compression signs appear, the longer the lantency of CSEP N1 wave is, and the more serious the spinal pathological damages are.

Objective To explore the preparation of liposomal clodronate and investigate its inducing effects on the apoptosis of peritoneal macrophages in rats after severe acute pancreatitis (SAP).Methods Liposomal clodronate was prepared by means of thin film. SAP rat model was established by retrograde injection of 5% sodium taurocholate into the pancreatic duct. The peritoneal macrophages were obtained from SAP rats. After exposure to different doses of liposomal clodronate (50, 100,150 μl), the PM proliferation was determined by MTT colourimetry. The apoptosis of PM was measured by flow cytometry and agarose gel electrophoresis, respectively. Results The prepared liposomal clodronate had a suitable encapsulation efficiency of clodronate (5.8%) with an average size of 200 nm. The spherical shape of liposome was confirmed by transmission electron microscope. Exposed to liposomal clodronate of different doses resulted in a obvious growth depression (P＜0.01). The apoptotic rate of the PM was (10.32±0.34) %, (18.16±0.49)% and (29.87±0.35)% in three different dose groups and the difference was marked (P＜0.01). 1.2% of agarose gel electrophoresis of DNA extracted from apoptotic macrophages induced by liposomal clodronate showed clearer and characteristic ladder following the liposomal clodronate concentration. Conclusion Liposomal clodronate has a definite effect on peritoneal macrophages in SAP rats.

Objective To investigate the effect of pregnancy on the potency of bupivacaine for spinal anesthesia in rats. Methods Female non-pregnant SD rats weighing 180-220 g and 17 day pregnant SD rats weighing 350-400 g were used in this study. The rats ( 18 non-pregnant, 18 pregnant) in which PE-10 catheter were successfully placed without complications were selected. The 18 non-pregnant rats were randomly divided into 3 groups (n =6 each): control group (group C), 2% bupivacaine group (group B2 ) and 4% bupivacaine group (group B4). The 18 pregnant rats were also randomly divided into 3 groups (n = 6 each): control group (group PC),2% bupivacaine group (group PB2 ) and 4% bupivacaine group (group PB4 ). Group C and PC received intrathecal (IT) normal saline 30 μl, and the other 4 groups received 2% or 4% bupivacaine 30 μl intrathecally. Analgesia was determined using the taifllick latency (TFL) before IT administration (baseline), and at 10 min, 20 min,30 min, 1 h, 2 h, 4 h, 1 d, 2 d, 3 d and 4 d after IT administtation. The percentage of the maximal possible effect (MPE) was calculated. Hind-limb motor function (MF) was also assessed. Results Compared with the baseline value, MPE at 10 min-2 h after administration and MF scores at 10 min-1 h after administration were significantly increased in group B2, MPE at 10 min-4 h after administration and MF scores at 10 min-1 h after administration were significantly increased in group B4;MPE at 10 min-1 d after administration and MF scores at 10 min2 h were significantly increased in group PB2 and MPE at 10 min-1 d after administration and MF scores at 10 min4 h were significantly increased in group PB4 ( P ＜ 0.05 ). Conclusion Pregnancy can enhance the potency of bupivacaine for spinal anesthesia in rats.

Intravoxel incoherent motion (IVIM) can distinguish the molecular diffusion from the pseudo-diffusion of microcircular perfusion to obtain true diffusion coefficient (D),pseudo-diffusion coefficient (D*) and perfusion fraction (f),which are sensitive to detect alterations in cellularity and microcirculation perfusion.IVIM can also evaluate early therapeutic effects,optimize treatment plan,predict prognoses,and provide information for choosing appropriate treatment methods.In this paper,the principle of IVIM and its application in tumor response evaluation were reviewed.

Objective To study the state and trends of Kesan disease in Henan province from 2004 to 2009. Methods Surveillance sites were selected: Guxian village of Luoning country from 2004 - 2007, Zuyang town of Lingbao city in 2008, and Shahe village of Lushi country in 2009. All residents of surveillance sites were examined by clinical and electrocardiogram, and suspected patients were inspected by chest X-ray to measure ardiothoracic ratio. Hair and wheat flour samples were collected and selenium levels were detected with hydride generation atomic fluorescence spectrometry. Results From 2004 to 2009, a total of 4034 people were examined.The numbers of chronic and latent KSD patients were 21 and 75 cases,respectively, and the incidence rates were 0.52%(21/4034) and 1.86%(75/4034), respectively . The number of abnormal electrocardiogram was 751 cases, and the incidence rate was 18.62%. The highest proportion of abnormal electrocardiogram was ST-T changes,accounting for 24.63%(185/751), followed by high-voltage, accounting for 18.11%(136/751), and left ventricular accounting for 13.85% (104/751). Sixty-one grain samples were collected and the wheat flour selenium level was averaged 0.034 mg/kg. Thirty hair samples were collected and the selenium median was 0.285 mg/kg. Conclusions The state of Keshan disease is in a steady state in Henna province, but higher rates of abnormal electrocardiogram is a serious problem and should be studied and prevented.

Objective To understand Kaschin-Beck disease(KBD) status in Henan Province and provide the basis for the further prevention and treatment of KBD. Methods Children aged 7 to 12 in 3 villages(Yaodian, Miaowa and Zhuyang) with the same environment such as topography, physiognomy,production mode and living habits in Shan County and Lingbao City were selected to undertake KBD clinical examination in 2008, X-ray examination of right hand and child hair samples and food samples were collected to determine the content of selenium. Selenium was determined using 2,3-Diaminonaphthalene method. Adults who were 16 years or older in 5 counties(Luoning, Lingbao, Mianchi, Shah and Lushi) were selected and examined for KBD. Results One hundred and ninty children aged 7 to 12 were clinically examined and clinical KBD were found, whereas 3 children were diagnosed as KBD by X-ray examination, the positive rate was 1.58% (3/190). All 20 521 adults were clinically examined and KBD prevelance rate was 6.10%(1251/20 521), including degree Ⅰ (3.97%,814/20 521), degree Ⅱ (1.77%, 364/20 521 ), degree Ⅲ (0.36%, 73/20 521). The average selenium contents in hair and food samples were (0.319±0.128)mg/kg and (0.031±0.009)mg/kg, respectively. Conclusions Child KBD in Henan Province is under control or almost under control, whereas the prevalence of adult KBD was relatively serious, which suggested that secondary prevention with the objective of clinically treating KBD patients should be strengthened.

Objective To observe the relationship between the change of endothelin-1 (ET-1), nitric oxide synthase(NOS) content and cerebral vasospasm after experiment Sprague-Dawley rat subarachnoid hemorrhage (SAH). Methods SD rat got the tail artery blood and followed prone positioning in a stereotaxic apparatus, injected autologous arterial blood or saline into cisterna magna,2 d later injected in the same way. For basilar artery (BA),internal carotid artery(ICA) ,and middle cerebral artery(MCA) diameter measurements,gelatin-india ink vascular casted,the blood ET-1 and NOS content were detected by immunoradiology or colorimetry measurement. Results Microangiography in SAH showed extensive macroscopic filling deficit,the diameter of MCA,ICA and BA ((169.33 ±8.67)mm, (227.33 ± 14.25) mm, (226.33 ±5.99) mm respectively) were shorter than those in control group((259.5 ±7.48)mm,(228.17 ±8.09)mm,(254. 67 ±8.48)mm respectively) (all P<0.05). Neuronal function score of 7d(9.45 ±1.77) was higher than control group(0.60 ±0.49) (P<0.05). Content of ET-1 and NOS in blood after SAH 7 d were(231.25 ± 19.45)g/L,(198.50 ±9.52) × 103U/L) ,(72.99 ±5.83)g/L, (230.76 ±17.06) × 103U/L),for sham group,there was significant differences (P<0.05). Conclusion Experiment rat double-hemorrhage method from tail artery can makes experimental subarachnoid hemorrhage model,neurological functional score is increased, neuronal function score is associated with diameter of MCA and ET-1 content.

Objective To investigate the apoptosis of Kupffer cell (KC) induced by lipsomal clodronate in rat with acute necrotizing pancreatitis (ANP). Methods Lipsomal clodronate was prepared by means of thin film, the model of ANP was established by injection of 5% sodium taurocholate of 4 ml/kg into the pancreatic capsule. The Kupffer cells were obtained from ANP rat. After exposure to different doses of lipsomal clodronate (0, 50, 100, 150 μl) , then the proliferation and apoptosis of KC was measured by MTT, flow cytometry and agarose gel electrophoresis of DNA. Results The prepared lipsomal clodronate had an average size of 100～200 nm, the spherical shape of liposome was uniform and confirmed by transmission electron microscope. When exposed to different concentration of lipsomal clodronate for 24 h, the growth suppression rate was 17. 4% , 24. 2% and 31. 1% , respectively, while the apoptosis rate of the KC was (14. 12 ±0.37)% , (18.74±0.43)% and (27.51 ±0.39)%, respectively; the difference was statistically significantly (P<0. 01) , the DNA of KC began degradation and gradually showed clear and characteristic ladder. Conclusions Lipsomal clodronate could induce apoptosis and suppress the growth of Kupffer cells in ANP rats.

BACKGROUND: There are few reports addressing the differentiation of bone marrow mesenchymal stem cells (BMSCs) into neurons, and the uncertainties mainly focused on the differentiated neurons had neuron morphology, but did not have neuron function. OBJECTIVE: To investigate the feasibility of rat bone marrow mesenchyma stem cells (BMSCs) differentiation into neuron-like cells and glial-like cells under rat hippocampal neuron's conditional medium. METHODS: Rat BMSCs at passage 5 were divided into 4 groups. The medium of hippocampal neurons and glial cells was added in the conditioned medium group. The Dulbecco's modified Eagle's medium containing bFGF was added in the basic fibroblast growth factor (bFGF) group. The serum-free medium containing Neurobasal and B27 was added in the serum-free medium group. The DMEM supplemented with fetal bovine serum was added in the negative control group. 12 and 24 hours following induction, neuron specific enolase (NSE), microtubule-associated protein-2 (MAP-2) and glial fibrillary acidic protein (GFAP) were detected using immunocytochemical staining in each group. NSE, MAP-2 and GFAP expression was determined using Western-blot assay. RESULTS AND CONCLUSION: 12 and 24 hours following induction, BMSCs were positive for MAP-2, GFAP and NSE in the conditioned medium, bFGF and serum-free medium groups, but negative in the negative control group. Compared with the negative control group, MAP-2 expression was significantly enhanced in the conditioned medium, bFGF and serum-free medium groups 24 hours following induction (P < 0.05), and the increased range was significantly greater in the conditioned medium group compared with other two groups (P < 0.05). No significant difference in NSE and GFAP expression was detected in the conditioned medium, bFGF and serum-free medium groups. Results suggested that hippocampal neuron conditioned medium can in vitro induce the differentiation of rat BMSCs into neuron-like cells and glial cell-like cells. Compared with the bFGF medium and serum-free medium, positive rate was greatest in the hippocampal neuron conditioned medium-induced neurons and glial cells.