Objective To purify AmpC beta-lactamase from Enterobacter cloacae and study its physical and chemical characteristics.Methods The bacteria were fragmentized by ultrasonication and AmpC beta-lactamase was purified by ion-exchange.The properties of the purified enzyme,such as molecular weight and isoelectric point were determined by electrophoresis.Results The purified AmpC beta-lactamase was obtained and its specificity to substrate was sufficient for classification of class C cephalosporinase.Conclusion AmpC can be successfully purified from Enterobacter cloacae and is effective for application.

Objective To evaluate the variability of four parameters of multi-focal electroretinogram (mERG) a-wave amplitude, b-wave amplitude, a-wave latent period, b-wave latent period. Methods Sixty normal eyes of 46 volunteers were divided into 3 groups of different ages. RETIscan 3 12 system was used to carry out mERG examination. The stimulus matrix of 61 hexagonal elements spanning the central 24?of the visual field. These hexons were scaled with eccentricity and divided into 5 rings. First-order kernel was selected. Results The variability of four parameters of mERG was great. The variability of b-wave latent period was the smallest, its coefficient of variatian was 4.52%～15.62%;that of a-wave latent period held the second place:10.29%~48.67%;that of b-wave amplitude was greater:25.92%~76.11%;that of a-wave amplitude was the greatest:43.82%~88.23%. The results of three groups showed that b-wave amplitude of ring 1 had the smallest variability. Conclusions The variability of latent period is smaller than that of amplitude; the variability of b-wave was smaller than that of a-wave. The longer the centrifugal distance, the lower the amplitude density of a-wave and b-wave. Physiological and anatomical factors might be important for the variability of parameters of multi-focal electroretinogram.

Objective To find the changes and effects of nitric oxide synthase activity in atherosclerotic rabbit models. Methods Thirty rabbits were divided into 3 groups at random: control group, atherogenic diet group, balloon-injury+ atherogenic diet group. Three months later underwent pharmacological triggering with Chinese Russell’s viper venom and histamine to make the plaque rupture. Lipid concentrations and the levels of nitric oxide (NO), NOS and hydroxy radical (OH) in the serum were obtained at different period, and pathologic changes were observed. Results In atherogenic diet group and balloon-injury+ atherogenic diet group, serum lipid concentrations markedly increased, but the levels of NO did not show any difference. The activity of NOS and OH levels were obviously increased after the atherogenic diet. But it reduced after pharmacological triggering and plaque rupture. Conclusion In early period of atherosclerosis, NOS activity up regulated and endothelium functions were compensated. But, When the atherosclerotic plaques were unstable, the activity of NOS descended obviously and endothelium function goes into incompensation.

ObjectiveTo study the correlations among age,sex,eye and mERG results.Methods60 normal eyes of 46 volunteers were divided into 6 groups at different ages.RETIscan 3.12 system of Rodenstock was used to carry out mERG examination.ResultsVariation of mERG parameters among normal eyes was significant.Age,sex and eyes have little influence on mERG results,except latency A was longer in male than in female.The size of pupil and fixation were found to influence the results directly.ConclusionsCare should be exercised in explaining the results.Disease history and other examinations shoud be taken into consideration.Attention should be given to the changes in wave-form and vision mountain in addition to amplitudes and latencies.

BACKGROUND:Col agen suture is made of col agen from animals, and has been widely used because it is absorbable, non-rejection and easy to produce, and convenient in use.
OBJECTIVE:To evaluate the effects of col agen suture and silk suture in wound healing after oral implant surgery.
METHODS:100 patients undergoing oral implantation were randomly assigned into col agen suture group and silk suture group. A 2-0 circular needle with absorbable col agen sutures and a 4-0 circular needle with non-absorbable silk sutures were employed for tension-free suture in the two groups. After 3, 5, 7 days of oral implantation, suture threads and wound healing were observed. The suture was removed at 14 days, and patients were reviewed at 14 days.
RESULTS AND CONCLUSION:The wound healing was better in the col agen suture group than the silk suture group at grade I (P<0.05). At 7 days postoperatively, the suture thread was mostly absorbed in the col agen group but not in the silk suture group. In addition, material alba was invisible in the col agen suture group but clear in the silk suture group. These results indicate that the col agen suture is more proper for tension-free suture than the silk suture, which is better matched to the healing time and keeps a better oral environment.

Objective To investigate the effects of Mailuoning on oxidative stress and ischemic brain injury. Methods A total of 126 healthy male Kunming mice were divided into sham operation (n = 18), normal saline control (n = 54) and Mailuoning (n = 54) groups. A middle cerebral artery occlusion (MCAO) model was induced Two hours after MCAO,Mailuoning injection and equivalent saline were injected via the tail vein in the Mailuoning and normal saline control groups, respectively, and then they were injected every other 24 h.Neurological score was performed, and brain water content, infarct volume, membrane potential,as well as protein oxidative stress metabolites such as 3-nitrotyrosine (3-NT), lipid oxidative stress metabolite 4-hydroxy-2-nonenal (HNE) and nucleic acid oxidative stress metabolite 8-hydroxy-2'-deoxyguanosine (8-OHdG) were detected at 12, 24 and 72 h after MCAO. Results Mailuoning injection could significantly improve the neurological function of cerebral ischemia in mice, decrease brain edema, and reduce infarct volume at different time points after cerebral ischemia Of those, it was most significant at 72 h. Mailuoning injection could reverse the decreased mitochondrial membrane potential in cerebral cortex and internal capsule, and significantly downregulate the increased 3-NT, HNE and 8-OHdG in cerebral cortex, internal capsule and serum after ischemia, of those, the effect of reducing HNE was most significant.Conclusions Mailuoning injection may effectively protect against ischemic brain injury in mice,and its mechanism is associated with inhibiting oxidative stress, particularly anti-lipid oxidation.

BACKGROUND:Olfactory bulb neurogenesis, transformation and maturation have been considered the hot topic. Olfactory bulb experience and nervous activity can influence olfactory bulb neurogenesis. However, no study reports that olfactory bulb functions can affect olfactory bulb neurogenesis in guinea pigs.
OBJECTIVE:To investigate the effect of unilateral olfactory functional deprivation on doublecortin, calbindin and parvalbumin expression in olfactory bulb of juvenile guinea pigs.
METHODS:Total y 24 guinea pigs were randomly divided into two groups, which were kil ed after establishing olfactory functional deprivation model through electric cautery injury at the left peripheral nostrils. At 3 and 6 weeks after modeling, the specimens were harvested. The expression change of doublecortin, calbindin and parvalbumin in two sides’ olfactory bulb of juvenile guinea pigs was detected by immunohistochemistry.
RESULTS AND CONCLUSION:The number of doublecortin, calbindin and parvalbumin positive cells in olfactory bulb at the un-deprived side was significantly higher than that at the deprived side at 3 and 6 weeks (P<0.05). This finding indicates that olfactory neural activities can affect neurogenesis and transformation in guinea pigs.

Objective To investigate the roles of Xenon-CT cerebral blood flow perfusion imaging in cerebral revascularization before surgery and efficacy evaluation.Methods The clinical data of 15 patients with symptomatic cerebral artery stenosis/occlusion of anterior circulation were analyzed retrospectively.Eight patients were treated with endovascular stenting,1 was treated with internal carotid endarterectomy,and 6 were treated with superficial temporal artery-middle cerebral artery bypass grafting.The regional cerebral blood flow (rCBF) detected by Xenon CT within 2 weeks before and after procedure and the modified Ranking scale (mRS) scores at 6 months after procedure were compared.Results (1) The mean rCBF value of 12 patients with abnormal blood perfusion of target vessels before procedure was 30±10 ml/(100 g·min) and that was 32±14 ml/(100 g·min) after procedure.Compared with before procedure,the difference was statistically significant (P<0.05).The mean rCBF value of 3 patients with normal blood perfusion of target vessels before procedure was 48±6 ml/(100 g·min) and that was 50±7 ml/(100 g·min) after procedure.Compared with before procedure,the difference was not statistically significant (P>0.05).(2) The postoperative mRS score was decreased in 8 cases and stable in 7 cases.Compared with before procedure,there were significant differences in mRS scores after procedure in 15 cases (P<0.05).During the follow-up period,none of the patients had new neurological impairment.Conclusion Revascularization can improve the presence of hemodynamic disorders in patients with symptomatic anterior circulation cerebral artery stenosis or occlusion of the target blood vessels in the distal local cerebral perfusion and neurological deficit symptoms.The patients with abnormal perfusion of preoperative Xenon-CT cerebral blood flow perfusion imaging may be more beneficial than those with normal perfusion.

BACKGROUND:Researches showed that the enriched environment could improve the cognitive dysfunction of rats with vascular dementia. However, there are few reports regarding its mechanism of action.
OBJECTIVE:To explore the effect of enriched environment on the cognitive dysfunction of rats with vascular dementia from the behavioral level.
METHODS:Vascular dementia models weremade by permanent ligation of bilateral common carotid arteries and were divided into vascular dementia group (n=8) and enriched environment group (n=12). Vascular dementia group was taken care under conventional breeding environment for 30 days, while the enriched environment group was subjected to the enriched environment for 30 days. Morris water maze test was adapted to test the cognitive function of rats between two groups. Immunohistochemistry and immunoblotting were applied to observe the number ofDCX+cels and DCX protein level in both groups. The number of DCX-labeled cels co-expressing NeuN was observed using immunofluorescence technique.
RESULTS AND CONCLUSION:(1) The escape latency in the vascular dementia group was longer than that in the enriched environment group (P< 0.05). The times across the platform was less in the vascular dementia group than that in the enriched environment group (P< 0.05). (2) In comparison with the enriched environment group, the number of DCX-positive cels andits protein level in the piriform cortex were significantly decreased in the vascular dementia group (P< 0.05). (3) The number of DCX/NeuN co-labeled cels in the piriform cortex was significantly less in the vascular dementia group than in the enriched environment group (P< 0.05). (4) These findings suggested that enriched environment could improve the cognitive dysfunction of rats with vascular dementia through promoting the expression and differentiation of the immature neurons.

Objective To investigate the relationship between genetic polymorphisms in nucleotide excision repair gene excision repair cross complementing group 6(ERCC6),xeroderma pigmentosum group A(XPA) and coal-burning-borne-arsenism in Guizhou Province.Method ERCC6 A3368G,ERCC6 C-6530G and XPA A23G gene polymorphisms were analyzed by polymerase chain reaction restriction fragment length polymorphism technique(PCR-RFLP) of 205 cases which were chosen as patients with arsenism and 187 residents as control group.Results The distributions of ERCC6 A3368G,ERCC6 C-6530G and XPA A23G in the case group were not statistically significant compared with those of the control group(x2 =3.209,2.963,3.335,all P ＞ 0.05); individuals carrying G allelomorphic gene(AG + GG) had a lower risk than individuals carring A allelomorphic gene(ORadj =0.282,95％CI:0.126-0.628,P =0.002); relationship was not found between single genetic polymorphisms of ERCC6 C-6530G,XPA A23G and coal-burning-borne-arsenism; the risk of arsenism was decreased for individuals carrying the following five genotypes combination:ERCC6 A3368G(AG + GG) genotype and ERCC6 C-6530G CC genotype(ORadj =0.287,95％CI:0.087-0.946,P=0.040); ERCC6 A3368G(AG + GG) genotype and ERCC6 C-6530G(CG + GG) genotype (ORadj =0.226,95％CI:0.077-0.661,P =0.007); ERCC6 A3368G(AG + GG) genotype and XPA A23G AA genotype (ORadj =0.150,95％CI:0.038-0.596,P =0.007); ERCC6 A3368G (AG + GG) genotype and XPA A23G(AG + GG) genotype(ORadj =0.325,95％CI:0.118-0.897,P =0.030) ; ERCC6 C6530G (CG + GG) genotype and XPA A23G AA genotype (ORadj =0.397,95％CI:0.162-0.975,P=0.036).Conclusions Individuals carring ERCC6 A3368G (AG + GG) genotype have a low risk of arsenism.There are five genotypes combination of three gene polymorphisms in two genes,ERCC6 and XPA,which may reduce the risk of coal-burning-borne-arsenism.