Hyaluronic acid(HA)is a linear polysaccharide chain composed of alternating ?-1,4-glucuronic acid(GlcA)and ?-1,3-N-acetylglucosamine(GlcNAc)moieties.Construction of engineering strain has become the prevailing strategy for increasing yield and improving its quality,especially the molecular weight.Here the molecular mechanism of HA biosynthesis in Streptococcus strains was reviewed,involving fermentation strains,operon structure,crucial enzyme and construction of engineering strains.In addition,the prevalent problems in HA fermentation production were also discussed and the protocols were tentatively put forward for the upcoming research and industrial production.

Animals ; Animals, Newborn ; Cells, Cultured ; Cyclic AMP ; metabolism ; Glucagon-Like Peptide 1 ; pharmacology ; Insulin ; secretion ; Islets of Langerhans ; drug effects ; secretion ; Peptide Fragments ; pharmacology ; RNA, Messenger ; genetics ; Rats

Background Cystoid macular edema(CME) is an important cause of visual impairment of central retinal vein occlusion(CRVO).Spectral-Domain optical coherence tomography(SD-OCT) has increased speed and higher resolution,offering a better chance of understanding the morphological changes and pathogenesis of CME. Objective This study was to survey the morphologic features of macular edema associated with CRVO by SD-OCT. Methods Clinical data of the patients with CRVO diagnosed in Department of Ophthalmology,Peking Union Medical College Hospital from March 2008 to August 2009 were retrospectively analyzed.SD-OCT features of macular edema induced by CRVO were analyzed and recorded.Results The average macular foveal thickness was(527.5±218.2) μm in macular edemas eyes.Main morphological changes included 55 cases(84.6%) of CME,15 cases of(23.1%) serous macular detachment(SMD),and 10 cases(15.4%) of simple macular edema,and these findings occurred at the same time in some eyes.Cystoid spaces in the parafoveal region were seen in the inner nuclear layer,outer plexiform layer and outer nuclear layer,and discontinuous or weak inner segment/outer segment(IS/OS) line was often seen in CME.The incidence of CME associated with incomplete posterior vitreous detachment(PVD) was 14.5%,and that of neural epithelial edema associated with incomplete PVD was 10.0%,showing an insignificant difference between them(χ2=0.000,P=1.000).The average area of SMD was 1838.4μm ×1428.1μm×190.1μm,and the incidence of partial PVD was higher(χ2=4.266,P=0.039).Conclusion SD-OCT can reveal the micro-morphological change of macular zone in macular edema eye.SD-OCT enabled visualization of its spatial extent in each retinal layer and the condition of IS/OS layer.Serous macular edema is related with partial PVD.

Objective To investigate the effects of hepatocyte growth factor(HGF) on proliferation and collagen synthesis induced by angiotensin Ⅱ(AngⅡ)in SD rat cardiac fibroblasts(CFbs),and determine the role it plays in hypertensive ventricular remodeling.Methods CFbs in SD rat were cultured in vitro and treated with different concentrations of AngⅡ and/or HGF.Collagen type Ⅰ synthesis of CFbs was measured by Western blotting,and proliferation of CFbs was detected by MTT assay. Results AngⅡ promoted collagen synthesis and proliferation in CFbs in a certain concentration range,which can be significantly inhibited by HGF. ConclusionHGF can inhibit the proliferation and collagen synthesis induced by AngⅡin SD rat CFbs,and may protect against hypertensive ventricular remodeling.

Objective To investigate the effect of transplantation of bone marrow mesenchymal stem cells (MSCs) in subarachnoid space on chronic neuropathic pain in rats. Methods One hundred and forty female SD rats weighing 180-200 g were used in this study. Chronic neuropathic pain (NP) was induced by ligation and separation of tibial and common fibular nerves (SNI). Two weeks after the surgery the animals were randomly divided into4 groups (n=35 each):group Ⅰ NP; group Ⅱ NP+ MSC (MSCs); group Ⅲ NP+ phosphate buffer saline (PBS) and group Ⅳ NP+ bone marrow monocyte (BNMCs). MSCs 10 μl, PBS 10 μl and BNMCs 10 μl were injected into subaraclmoid space at 2 weeks after surgery in group Ⅱ , Ⅲ and Ⅳ respectively. Paw withdrawal threshold to yon Frey filament stimulation (PWT) was measured before surgery (T0, baseline), at 2 weeks after surgery (T1) and 1, 2, 3, 4 and 5 weeks after subarachnoid injection (T2-6). Five animals were killed at T1-6 in each group and their lumbar enlargements were removed for determination of BDNF mRNA expression. Results PWT was significantly decreased by SNI at T1 in all 4 groups, and at T2-6 in group Ⅰ , Ⅲ and Ⅳ as compared with the baseline at T0 (P ＜ 0.05). Subarachnoid MSC transplantation significantly reduced mechanical hyperalgesia at T2-6 and up-regulated BDNF mRNA expression at T2-4 as compared with that at T1 (P ＜0.05). There was no significant change in PWT and BDNF mRNA expression after subarachnoid PBS and BNMCs injection in group Ⅲ and Ⅳ (P ＞ 0.05). Compared with group Ⅰ , PWT was significantly increased and BDNF mRNA expression was up-regulated in group Ⅱ (P ＜ 0.05), but no significant change in PBS and BNMCs was found in group Ⅲ (P ＞ 0.05) .Conclusion Up-regulation of BDNF mRNA expression in the spinal cord may be involved in the amelioration of chronic neuropathic pain by subarachnoid bone marrow mesenchymal stem cell transplantation.

BackgroundIdiopathic epiretinal membranes(ERMs) is a common eye disease condition that leads to progressive decline of visual acuity. Studying the risk factors relating to this disease will shed light on its pathogenesis and allow opthalmologists to screen the affected individuals among the high-risk population and prepare for prevention and management strategies. ObjectiveThis survey was to investigate the risk factors of idiopathic ERMs in the population undergoing routine health check-ups. MethodsThe clinical data of idiopathic ERMs was obtained from the population of routine health check-ups in Peking Union Medical College Hospital from November 2009 to October 2010. The examination outcomes were compared between the individuals with and without idiopathic ERMs. The demographic and clinical factors associated with idiopathic ERMs were analyzed and assessed using univariate and multivariate logistic regression analyses. Result A total of 27 400 people were included in the survey and idiopathic ERMs were diagnosed in 76 cases. No obvious eye complaint was obtained from the idiopathic ERMs. The number of people affected with idiopathic ERMs was 12 ( 12/11 659 ) in the below 40 years group, 21 (21/4595) in the 51-60 years group and 32 (32/2544) in the over 60 years group. Hypertension, diabetes, diedyslipidemia, renal function insufficiency ,and cataract were found in 42％ ,5％ ,66％ ,6％ and 8％ of the patients, respectively. The univariate logistic regression analyses revealed that significant correlations were found between age,hypertension,hyperlipidemia and history of cataract( P＜0. 01 ). Multivariate regression models showed that the risk of idiopathic ERMs increased in age of 51-60( OR=2. 5,95％ CI:1. 2-5.4,P=0.02) and over 60 years( OR =7.3,95％ CI:3.4-15.6 ,P＜0.01 ) and patients suffering from hyperlipidemia ( OR--2. 1,95％ CI:1. 3-3.5, P＜0. 01 ). ConclusionsOver the age of 50 years and hyperlipidemia are primary risk factors of idiopathic ERM.

1,3-propanediol production by microbial fermentation has become the research hot spot for its amiability with the environment. Here the molecular mechanism of glycerol bioconversion to 1,3-propanediol was outlined by elucidating the fermentation strains, metabolic pathways, regulon and key enzymes. Of enzymes, glycerol dehydrogenase, the velocity-limiting enzyme in glycerol reductive pathway, was emphatically discussed with regard to its molecular structure and reactivating factors. This paper aims to provide the basis for genetic modification of fermentation strains.
Bacteria ; enzymology ; genetics ; metabolism ; Bacterial Proteins ; genetics ; metabolism ; Biosynthetic Pathways ; Fermentation ; Gene Order ; Glycerol ; metabolism ; Hydro-Lyases ; genetics ; metabolism ; Industrial Microbiology ; methods ; trends ; Propylene Glycols ; metabolism ; Sugar Alcohol Dehydrogenases ; genetics ; metabolism

To compare the effect of insulin glargine combined with nateglinide and continuous subcutaneous insulin infusion(CSII) during intraoperative period in type 2 diabetic patients with fracture. Both of the managements made blood glucose under control [fasting blood glucose(6.89±1.96)vs(6.75±2.33)mmol/L] in similar period [(3.6±1.6)vs(2.9±1.2) d,both P>0.05]. The mean blood glucose was lower in patients treated by CSII than that of the other group.

Objective To investigate the effect of two different odontoblast inducer on the proliferation and apoptosis of rat adiposed-derived stem cells.Methods Adiposed-derived stem cells were collected by enzyme digestion from inguinal fat pads of 4 days post natal mice.Immunocytochemistry was performed to identify the cells.MTT and flow cytometry were tested the prolifera-tion and apotosis of adiposed-derived stem cells by co-cultured with tooth germ cell conditioned medium(TGC-CM)or dentin non-collagenous protein medium (DNCPM).Results Cells displayed a fibroblast-like appearance and positively expressed CD44 and CD105 when cufured to the secend yeneration.After 3 day the cells polarity changed by co-cultured.Count of cells were no obvious change by TGC-CM co-cultured,while that ruduced significantly by DNCPM co-cultured.It confirmed that the proliferation rate of ADSCs in TGC-CM group and control group is higher than DNCPM group(P <0.05),while the apotosis of that in DNCPM group is higher TGC-CM group(P <0.05).Compared with control group,the results had no significant difference(P >0.05).Conclusion TGC-CM may have more advantage as inducer in rat adiposed-derived stem cells differentiate into dentin like cells than DNCPM.

Background Uveal effusion syndrome is uncommon in clinic.To understand the clinical characteristics of uveal effusion syndrome is helpful for rescuing visual acuity of patient.Objective This study was to discuss the diagnosis,classification and surgical outcome of uveal effusion syndrome.Methods This was a descriptive study.The clinical data of 14 eys from 10 patients with uveal effusion syndrome,ineluding ophthalmologic examination,B-scan sonography,ultrasound biomicroscopy (UBM),fundus fluorescence angiography (FFA),indocyanine green angiography (ICGA),surgical treatment and prognosis,were retrospectively analyzed.The follow-up period was 6 months.Results The fundus findings of all impacted eyes showed bullous-shape retinal detachment (RD).B-scan sonography revealed retinal and choroidal detachment.A annular peripheral ciliochoroidal detachment was observed in the cases under the UBM.FFA exhibited leopard spots without any leakage from choroid into the subretinal space.ICGA demonstrated diffusely choroidal granular hyperfluorescence in the very early phase,which presented with an increasing intensity as time lapse until the late phase.Full-thickness sclerectomy was performed on 4 eyes of 2 patients and subscleral sclerectomy was performed in 1 eye of 1 patient,achieving a retinal anatomic reattachment after surgery.All of the patients finished the fellow-up.No recurrence of RD was seen during the followup duration.Conclusions Comprehensive preoperative evaluation,including ophthalmologic ultrasonography,MRI and CT,is crucial for accurate classification of uveal effusion syndrome and determine of proper management strategy.