Effect of transcutaneous electrical acupoint stimulation on catheter related bladder discomfort after ureteroscopic lithotripsy / 中国针灸

OBJECTIVE@#To verify the efficacy of transcutaneous electrical acupoint stimulation (TEAS) on catheter related bladder discomfort after ureteroscopic lithotripsy.@*METHODS@#Sixty male patients with selective ureteroscopic lithotripsy under general anesthesia were randomly divided into a TEAS group (30 cases, one case dropped off) and a sham TEAS group (30 cases, 2 cases dropped off). Before anesthesia induction, the patients in the TEAS group were treated with TEAS at Guanyuan (CV 4), Zhongji (CV 3), Zusanli (ST 36) and Sanyinjiao (SP 6) for 30 min, with disperse-dense wave, frequency of 2 Hz/ 15 Hz and current intensity of 6 to 10 mA. The patients in the sham TEAS group were treated with the same TEAS device at the same acupoints, but no electrical stimulation was given. After 30 min, anesthesia induction started. The total dosages of propofol and remifentanil in the two groups were recorded, and the time of operation and anesthesia, the time of wake-up and the time of stay in postanesthesia care unit (PACU) were recorded. The postoperative recovery was evaluated 5 min (T) after wake-up, 1 h (T), 2 h (T) and 6 h (T) after the operation, including the severity of urinary tract irritation and visual analogue scale (VAS) score. The occurrence of adverse reactions was observed, such as nausea and vomiting, dizziness and headache.@*RESULTS@#The dosage of remifentanil in the TEAS group was significantly lower than that in the sham TEAS group (0.05). Compared with the sham TEAS group, the incidence of more-than-moderate urinary tract irritation symptoms in the TEAS group was reduced (<0.05), and the VAS scores 1 and 2 h after operation were reduced (<0.05).@*CONCLUSION@#The 30-min TEAS at Guanyuan (CV 4), Zhongji (CV 3), Zusanli (ST 36) and Sanyinjiao (SP 6) before anesthesia induction could significantly control the severity of postoperative urinary tract irritation in patients with ureteroscopic lithotripsy, reduce the dosage of anesthetic drugs and relieve postoperative pain.

Gene cloning, subcellular localization and expression analysis of the AsERF1 gene from Aquilaria sinensis / 药学学报

Ethylene-response factors, which are a subfamily of the AP2/ERF family, play an important role in ethylene signal transduction, plant growth and plant resistant. In this study, a full-length cDNA of the AsERF1 gene was cloned from Aquilaria sinensis. Sequence analysis, prokaryotic expression and purification, subcellular localization, tissue-specific analysis and expression analysis under different abiotic stresses was performed. The open reading frame (ORF) of the AsERF1 gene was 691 bp, encoding a protein of 229 amino acids with a predicted molecular mass of 25.36 kD. The AsERF1 protein contained the conserved AP2 sequence of ERF protein. A phylogenetic analysis indicated that the AsERF1 protein showed greatest sequence similarity with ERF2 from Populus trichocarpa. The recombinant AsERF1 protein was expressed in Escherichia coli BL21(DE3) cells using the prokaryotic expression vector pET28a-AsERF1 and the recombinant AsERF1 protein was purified. Agrobacterium-mediated protein expression experiments demonstrated that AsERF1 mainly localized to the nucleus. Expression analysis indicated that AsERF1 was primarily observed in leaves. The AsERF1 expression level was induced by salt, drought, low temperature and CdCl2 treatment, while the abundance of AsERF1 was most significantly induced by drought stress. These results provide valuable insights into the role of AsERF1 in plant defense and the mechanism of agarwood formation.

The effect of SvO2-guided early goal directed fluid therapy on hemodynamic and oxygen dynamics in septic shock pig model / 天津医药

Objective To evaluate the effect of SvO2-guided early goal directed fluid therapy on hemodynamic and oxygen dynamics in septic shock pig model. Methods Twelve Bama miniature pigs (male, 21-24 kg) were equally randomized into 2 groups, group C and group G. Septic shock was induced by intravenous infusion endotoxin. Group C received hemodynamic support aiming central venous pressure at 8 to 12 mmHg, urinary output 0.5 mL/kg per hour, and mean arterial pressure greater than 65 mmHg. Group G maintained SvO2 greater than 0.65 in addition to the above indicators. The interventions lasted 6 h and at T0-T8 (0, 60, 120, 180, 240, 300, 360, 420 and 480 min) recorded temperature, hemodynamic and oxygen dynamics indexes for each group, and recorded 6 hours for accumulated liquid volume, vascular active drug, and changes of urine. Results There were no significant differences in mean arterial blood pressure (MAP), heart rate (HR) and systemic vascular resistance index (SVRI) at each time point between group G and group C ( P>0.05). Values of CI and CVP were increased at T4-T8 in group G (P<0.05). Values of MPAP and PVRI were decreased at T8 in group G (P<0.05). Values of SvO2 were increased at T3-T8, O2ER were decreased at T3-T8 (P<0.05), DO2 were increased at T4-T8 (P<0.05), Lac were decreased at T5-T8, andΔp(CO2) was decreased at T8 in group G (P<0.05). There were no significant differences in values of VO2 at T1-T8 between two groups (P>0.05). The amount of intravenous infusion and urine volume were more and the amount of norepinephrine was less in animals of group G (P<0.05). The dosage of dobutamine was more in animals of group G, and which was not used in animals of group C. Conclusion SvO2 guided fluid therapy is more effective than conventional treatment to stabilize hemodynamics and oxygen kinetics, which is characterized by the increased cardiac output, increased oxygen supply, normal oxygen uptake rate and good tissue perfusion.

Cloning and expression analysis of allene oxide cyclase gene from Aquilaria sinensis / 药学学报

Allene oxide cyclase (AOC), a key enzyme in biosynthesis of jasmonic acid, plays an essential role in the plant defense system. In present study, a full length cDNA of AsAOC gene was cloned by the reverse transcription PCR from Aquilaria sinensis calli. Meanwhile, the bioinformatics, prokaryotic expression, purification, tissue-specific expression analysis, and expression analysis under different abiotic stresses and hormone treatments were performed. The open reading frame (ORF) of AsAOC1 gene was 753 bp, encoding a protein of 251 amino acids with a calculated molecular mass (MW) of 27.46 kD. Bioinformatic analysis showed that AsAOC1 protein contains a conserved allene_ox_cyc domain in C-terminus. The phylogenetic analysis indicated that AsAOC1 protein had the highest level of homology with the AOC protein from Morus notabilis. The recombinant AsAOC1 protein was successfully expressed in Escherichia coli BL21(DE3) cells using the prokaryotic expression vector pET28a-AsAOC1 and was purified by Ni2+ affinity chromatography. Expression analysis in different tissues indicated that AsAOC1 was primarily observed in stems, and then stem tips and roots, following by leaves. The transcript level of AsAOC1 was induced by various abiotic stresses including salt, drought, cold, and heavy metal stress. Furthermore, AsAOC1 expression level was enhanced upon methyl jasmonate (MeJA), salicylic acid (SA), gibberellin (GA3), and abscisic acid (ABA) treatments. These results provide valuable insights into the role of JA in the mechanism of agarwood formation and plant defense system.

Neuroprotective effects of Ginkgo biloba extract and Ginkgolide B against oxygen-glucose deprivation/reoxygenation and glucose injury in a new in vitro multicellular network model / 医学前沿

Acute ischemic stroke (AIS), as the third leading cause of death worldwide, is characterized by its high incidence, mortality rate, high incurred disability rate, and frequent reoccurrence. The neuroprotective effects of Ginkgo biloba extract (GBE) against several cerebral diseases have been reported in previous studies, but the underlying mechanisms of action are still unclear. Using a novel in vitro rat cortical capillary endothelial cell-astrocyte-neuron network model, we investigated the neuroprotective effects of GBE and one of its important constituents, Ginkgolide B (GB), against oxygen-glucose deprivation/reoxygenation and glucose (OGD/R) injury. In this model, rat cortical capillary endothelial cells, astrocytes, and neurons were cocultured so that they could be synchronously observed in the same system. Pretreatment with GBE or GB increased the neuron cell viability, ameliorated cell injury, and inhibited the cell apoptotic rate through Bax and Bcl-2 expression regulation after OGD/R injury. Furthermore, GBE or GB pretreatment enhanced the transendothelial electrical resistance of capillary endothelial monolayers, reduced the endothelial permeability coefficients for sodium fluorescein (Na-F), and increased the expression levels of tight junction proteins, namely, ZO-1 and occludin, in endothelial cells. Results demonstrated the preventive effects of GBE on neuronal cell death and enhancement of the function of brain capillary endothelial monolayers after OGD/R injury in vitro; thus, GBE could be used as an effective neuroprotective agent for AIS/reperfusion, with GB as one of its significant constituents.

Structural insights into the regulatory mechanism of the Pseudomonas aeruginosa YfiBNR system

YfiBNR is a recently identified bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) signaling system in opportunistic pathogens. It is a key regulator of biofilm formation, which is correlated with prolonged persistence of infection and antibiotic drug resistance. In response to cell stress, YfiB in the outer membrane can sequester the periplasmic protein YfiR, releasing its inhibition of YfiN on the inner membrane and thus provoking the diguanylate cyclase activity of YfiN to induce c-di-GMP production. However, the detailed regulatory mechanism remains elusive. Here, we report the crystal structures of YfiB alone and of an active mutant YfiB(L43P) complexed with YfiR with 2:2 stoichiometry. Structural analyses revealed that in contrast to the compact conformation of the dimeric YfiB alone, YfiB(L43P) adopts a stretched conformation allowing activated YfiB to penetrate the peptidoglycan (PG) layer and access YfiR. YfiB(L43P) shows a more compact PG-binding pocket and much higher PG binding affinity than wild-type YfiB, suggesting a tight correlation between PG binding and YfiB activation. In addition, our crystallographic analyses revealed that YfiR binds Vitamin B6 (VB6) or L-Trp at a YfiB-binding site and that both VB6 and L-Trp are able to reduce YfiB(L43P)-induced biofilm formation. Based on the structural and biochemical data, we propose an updated regulatory model of the YfiBNR system.

Comparison of the status of STAT4 tyrosine phosphorylation in peripheral T-lymphocytes induced by IL-12 in rheumatoid arthritis and osteoarthritis / 中国骨伤

<p><b>OBJECTIVE</b>To compare the levels of STAT4 tyrosine phosphorylation in peripheral T-lymphocytes induced by IL-12 in rheumatoid arthritis (RA) and osteoarthritis (OA).</p><p><b>METHODS</b>From May 2007 to August 2009, peripheral blood mononuclear cells (PBMCs) were isolated from RA patients [RA group, all the cases were female, the age was from 28 to 55 years with an average of (45.0 +/- 13.0) years] and OA patients [OA group, all the cases also were female; the age was from 55 to 75 years with an average of (67.0 +/- 9.6) years]. The purity of T-lymphocytes from PBMCs was accredited by flow cytometry. The IL-12 of 50 ng/ml added in T-lymphocytes, the levels of STAT4 tyrosine phosphorylation were detected by western blot after different time intervals (0, 10, 30, 60 min).</p><p><b>RESULTS</b>The purity of T-lymphocytes were above 91% through diremption and depuration for peripheral blood monouclear cells. The levels of STAT4 tyrosine phosphorylation in T-lymphocytes from RA induced by IL-12 were higher than that from OA in the different times (10, 30, 60 min); after 30 min, its levels from RA and OA achieved to crest value.</p><p><b>CONCLUSION</b>STAT4 in peripheral T-lymphocytes of rheumatoid arthritis was more easily to be activated than osteoarthritis.</p>

Treatment of fracture of multiple ribs with absorbable rib fixed nail and dacron flap in 12 patients / 中国骨伤

<p><b>OBJECTIVE</b>To introduce the methods of dacron flap application and its indications in treating fracture of multiple ribs, in order to reduce the incidence of the complications of fracture displacement.</p><p><b>METHODS</b>From September 2006 to March 2008, 12 patients with fracture of multiple ribs were treated with absorbable rib fixed nail and dacron flap. Included 8 males and 4 females,the age was from 22 to 51 years with an average of 38.2 years,the operative time was 2 hours to 3 days after injured. All the patients were closed injury and simultaneously accompanied with significant chest pain and chest tightness. 4 cases with dyspnea, blood in sputum and blood oxygen saturation decreased. The X-ray showed 3 cases of unilateral fracture and 9 cases of bilateral rib fractures and all cases accompanied with hemopneumothorax.</p><p><b>RESULTS</b>All patients were followed up from 2 to 26 months with an average of 8 months. All the fractures healed. According to clinical criteria, pain, breathing, ribs alignment etc. to observe the effect, 10 cases got excellent result, 1 case good, 1 case poor.</p><p><b>CONCLUSION</b>It is safe and effective to use absorbable rib fixed nails and dacron flap for treating fracture of multiple ribs and especially for the patients of osteoporosis, comminuted fracture or oblique fracture.</p>

Hydroa vacciniforme-like cutaneous T cell lymphoma: a case report and literature review / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical features, diagnosis and therapy of hydroa vacciniforme-like cutaneous T cell lymphoma.</p><p><b>METHODS</b>The clinical presentations and the findings of laboratory examinations and skin biopsy of affected tissue in a child with hydroa vacciniforme-like cutaneous T cell lymphoma were retrospectively reviewed.</p><p><b>RESULTS</b>The child manifested as rash, fever and lymph node intumesce. Rash was pantomorphia, including edematous erythema, vesicles, crusts, necrosis and depressed scar, and it was mild in winter and severe in summer, mainly involving in the face and extremities. Epstein-Barre virus (EBV)-IgM was positive. Histopathological findings revealed focal lymphocyte invasion in subcutaneous panniculus adiposus, mainly surrounding the blood vessels. Immunohistochemistry showed CD3 (+), CD43 (+), CD20 (-), pax-5 (-), TIA (+), CD5 (+), CD8 (+), Granmye (+) and CD4 (-). The clinical symptoms were improved after glucocorticoid treatment in this child.</p><p><b>CONCLUSIONS</b>Hydroa vacciniforme-like cutaneous T cell lymphoma has special clinical manifestations. This disorder may be definitely diagnosed by skin biopsy of affected tissue and immunohistochemistry assay. Glucocorticoid treatment is effective. EBV infection may be related to the development of this disorder.</p>

Toxicity of acrylamide on male reproduction / 中华男科学杂志

Acrylamide is a common chemical material, extensively used in industry and scientific experiments. Recently, it has been reported that starchy food cooked at high temperature can produce acrylamide. Acrylamide monomer has several toxic effects and the extensive concern for its toxicity has arisen with the finding of acrylamide formation in some processed foods. Researches have shown that acrylamide monomer can cause reproductive toxicity, including toxic effects on male reproductive behavior, male reproductive endocrine function and spermatogenesis. The mechanisms may include the effects of acrylamide on Leydig cells, the formation of motor protein/ chromosomal/DNA alkylation and damage by oxidative stress.

Subchronic exposure to acrylamide affects reproduction and testis endocrine function of rats / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the effect of subchronic exposure to acrylamide on the reproduction and testis endocrine function of rats.</p><p><b>METHODS</b>Forty healthy adult male SD rats were randomly divided into 4 groups of equal number, exposed to acrylamide at the dose of 0, 4, 10 and 18 mg/(kg x d) respectively for 9 weeks, and then subjected to the determination of the hindlimb landing foot splay, sperm vitality and morphology, the activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) in the testis homogenate, and the levels of testosterone (T) and estradiol (E2) in the serum and testis homogenate. Based on the primary Leydig cell culture models exposed to acrylamide of 0, 0.1, 0.75, 4 and 8 mmol/L, the activity of Leydig cells was measured by the CCK-8 method.</p><p><b>RESULTS</b>Following acrylamide exposure, the hindlimb landing foot splay increased markedly with dose increase (P < 0.01). The rates of sperm vitality were (6.86 +/- 5.46)%, (65.43 +/- 5.16)%, (60.86 +/- 4.26)% and (46.86 +/- 2.73)% in the exposed groups, significantly lower than in the control (P < 0.01); the rates of abnormal sperm were (39.00 +/- 10.95)%, (35.43 +/- 7.54)%, (45.71 +/- 13.28)% and (56.71 +/- 17.01)%, significantly increased in the 10 and 18 mg/(kg x d) groups (P < 0.05); ACP activities were (82.93 +/- 11.05), (73.52 +/- 8.77), (77.67 +/- 3.04) and (68.56 +/- 3.09) U/g prot, showing a decreasing tendency, while ALP activities were (0.96 +/- 0.15), (1.07 +/- 0.22), (1.12 +/- 0.22) and (0.74 +/- 0.10) U/g prot, displaying a tendency of first increasing and then decreasing. Both ACP and ALP activities were inhibited significantly in the 18 mg/(kg x d) group as compared with the control (P < 0.05). A marked reduction was noted in T levels in the serum, (13.44 +/- 4.76), (7.69 +/- 3.84), (5.23 +/- 1.42) and (1.36 +/- 0.86) ng/ml, as well as in the testis homogenate, (4.95 +/- 1.64), (3.01 +/- 0.76), (2.44 +/- 0.91) and (0.85 +/- 0.49) ng/mg prot, (P < 0.01), but no significant changes were observed in 17beta-E2 levels. After 24 hours exposure to acrylamide, the optical densities were 0.82 +/- 0.06, 0.56 +/- 0.07, 0.44 +/- 0.06, 0.26 +/- 0.03 and 0.45 +/- 0.21, showing an evident inhibition of the activity of Leydig cells at the dose of 0.1, 0.75, 4 and 8 mmol/L (P < 0.01).</p><p><b>CONCLUSION</b>Subchronic exposure to acrylamide could affect the normal development of sperm, cause changes of the activity of some enzymes in the testis and significantly influence hindlimb motor coordination. Acrylamide directly damages Leydig cells and affects the endocrine function of the testis.</p>

Total knee arthroplasty for extension ankylosing deformity / 中华外科杂志

<p><b>OBJECTIVE</b>To discuss the outcomes and complications of total knee arthroplasty (TKA) for extension ankylosing deformity of the knee.</p><p><b>METHODS</b>From January 1996 to June 2006, total knee arthroplasty was performed on 8 patients (9 knees) with extension ankylosing deformity. The preoperative ROM of all patients was 0 degrees . Preoperative knee and function score of KSS were 44 points (from 10 to 68) and 17 points (from -10 to 55) respectively.</p><p><b>RESULTS</b>The complications of all TKAs included patellar tendon avulsion in 1 knee, partial fracture of inferior patella in 1 knee, hematoma in 1, superficial infection in 1. All patients were followed up for an average of 40.4 months (from 7.0 to 120.0). The average postoperative ROM was 89 degrees (from 50 degrees to 120 degrees ). Postoperative knee and function score of KSS were 81 points (from 55 to 93) and 79 points (from 50 to 90) respectively. Extension lag occurred in 2 knees, one was 10 degrees and the other was 25 degrees . One knee had undergone re-revision of changing the thicker tibial spacer for the reason of instability of joint 1 year after revision.</p><p><b>CONCLUSIONS</b>TKA performed in extension ankylosing deformity can get less satisfactory clinical results comparing with fixed flexion deformity. Exposure of the knee joint and separation of the fused bones, providing a mobile joint space plays crucial procedure for the next step of surgery. Preservation of sufficient bone stock of patella, protection of patellar tendon and blood supply of the knee and proper soft tissue balance are the key to TKA for extension ankylosing deformity.</p>

Total knee arthroplasty and perioperative management of hemophilic arthritis / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the clinical results and perioperative management of primary total knee arthroplasty (TKA) in hemophilic patients.</p><p><b>METHODS</b>From February 1997 to February 2006, the data of 6 total knee arthroplasty performed in 4 hemophilic patients was reviewed retrospectively. The values of coagulation factor were maintained at suitable level by monitoring the activity of the factors and their inhibitors during perioperative period. The mean follow-up time was 4.4 years, knee society score and the last postoperative radiographs were recorded.</p><p><b>RESULTS</b>After TKA, the hemophilic patients felt pain of knee relieved, the knee function was improved, but the range of motion increased limitedly. At the early post-operative stage, 3 knees in 2 patients with hemarthrosis or muscle bleeding, 1 of the 2 patients complicated with formation of inhibitor of factor VIII and healing problem in 1 knee after TKA, 1 patient with transient paralysis of the common peroneal nerve, 1 patient with venous circulation insufficiency crisis, but no compartment syndrome. In the late stage after TKA, 1 patient with hemarthrosis of both elbows, but no late infection, loosening, displacement and fracture of the prosthesis in the 6 knees.</p><p><b>CONCLUSIONS</b>Total knee arthroplasty could alleviate knee pain and improve joint function in advanced severe hemophilic arthritic patients. It is important to monitor the activity and inhibitors of coagulation factor VIII or IX, which could decrease the early and late postoperative complications.</p>

Case Report of Mixed Connective Tissue Disease Complicating Pulmonary Hypertension and Its Literature Review / 实用儿科临床杂志

Objective To investigate the diagnosis and treatment of mixed connective tissue disease(MCTD)complicating pulmonary hypertension(PAH) in childhood in order to improve the recognition of this disease.Method According to the symptoms,signs,past history,labratory examinations,the child′s disease was diagnosed and treated,and the relative literature was reviewed.Results The main symptom of the child was interruptable apsychia.Ultrasound showed severe PAH,positive of anti-RNP antibody.After given immunosuppressant and decreased PAH,the patient′s condition was more improved.Conclusions MCTD complicating PAH in childhood onstes delitescently,and it′s difficult to diagnose.Recognition should be elevated to diagnose and treat it earlier.The prognosis can be improved.

Expression of Intercellular Adhesion Molecule-1 in Brain Edema Induced by Lipoposacchride in Rats under Action of Dexamethasone / 实用儿科临床杂志

Objective To explore the expression of intercellular adhesion molecule-1(ICAM-1) in the brain edema induced by lipoposacchride(LPS) in rats under the action of dexamethasone.Methods One hundred and fifty healthy SD rats were randomly divided into three groups of 50 each:normal saline group(NS group),LPS group and dexamethasone group(DXM group).Each group were again divided into 5 groups:4,6,12,24 and 48 h group.Brain edema was induced by LPS.Immunohistochemistry staining methods were used to measure the expression of ICAM-1 in brain tissue of brain edema induced by LPS in rats.And the level of evans blue(EB) was aslo determined.Results At each time point,the content of brain tissue and evans blue(EB) in LPS and DXM group all increased significantly than those in NS group(Pa0.05).In LPS group,brain water content and EB content,expressing quantity of ICAM-1 and brain water content,expressing quantity of ICAM-1 and EB content all had positive relationship(r=0.537,0.467,0.549 Pa

Improvement of the thermostability of xylanase by N-terminus replacement / 生物工程学报

The hybrid xylanase TB was constructed by the substitution of the N-terminus segment of the Streptomyces olivaceoviridis xylanase XYNB with corresponding region of Thermomonosporafusca xylanase TfxA. The hybrid gene tb, encoding the TB, was correctly expressed in Escherichia coli BL21 and Pichia pastoris GS115. TB was purified and its enzymatic properties were determined. The results revealed that the optimal temperature and optimal pH of TB were at 70 degrees C and 6.0, which have been obviously improved compared with those of XYNB. The thermostability of TB were all about six-fold of XYNB's after incubating the properly diluted enzyme solutions at 80 degrees C and 90 degrees C for 3min, respectively. The pH stability of TB was 5 to approximately 9, which was narrower than that of XYNB. Still, TB remains a high specific activity as XYNB does. Analysis of a homology modeling and sequence similarity were used to reveal the factors influencing the enzymatic properties of TB and the discussion for the relationship between structure and function of xylanase was given.

Improving phytase expression by increasing the gene copy number of appA-m in Pichia pastoris / 生物工程学报

In order to improve the fermentation potency of phytase in recombinant host and decrease the production cost, the pichia expression vector pGAPZalpha-A was modified by introduction of an AOX1 promoter from vector pPIC9 and the resulted vector pAOXZalpha is an methanol induced vector. After that, a phytase gene appA-m was cloned into pAOXZalpha to construct the recombinant vector pAOXZalpha-appA-m. The recombinant Pichia pastoris 74#, which already contains one copy of appA-m and its fermentation potency exceeded 7.5 x 10(6) IU/mL, was used as the host strain for the transformation of pAOXZalpha-appA-m. The Pichia pastoris transformants were gained by electroporation. PCR results indicated that the appA-m expression box has integrated into the genome of Pichia pastoris and the original construction of phytase gene has not changed. SDS-PAGE analysis revealed that phytase was overexpressed and secreted into the medium supernatant. Recombinants with high expression level were screened and used for fermentation. In 5L fermentor, the expression level of phytase protein achieved 4 mg/mL and the phytase activity (fermentation potency) exceeded 1.2 x 10(7) IU/mL, which was about 1.6-fold compared with that of the host strain 74#. Moreover, the improved recombinant Pichia pastoris is excellent at expression stability and heredity stability.

Revision hip arthroplasty with the cementless prosthesis: 4 years follow-up study / 中华外科杂志

<p><b>OBJECTIVE</b>To examine the two to eight-year results associated with the use of this hip system.</p><p><b>METHODS</b>Between November 1996 and January 2001, 56 revision total hip arthroplasties with insertion of a Zweymüller BICON-PLUS cup and a cementless SLR-PLUS stem were performed in 55 consecutive patients (average age, fifty-nine years old, range, thirty to eighty years old).</p><p><b>RESULTS</b>At the time of the latest follow-up, 23 patients (24 hips) had lost to follow-up, leaving 32 patients for a minimum of 2 years of clinical and radiographical follow-up. The mean follow-up time was 4 years. Only 3 peri-operative complications occurred, including 1 great trochanter fracture during implant removal, 1 dislocation 2 d after operation with successful closed reduction, and 1 deep wound infection which necessitated reentry and debridement. No femoral stems or cups needed re-revision surgery. The average Harris hip score increased from 40.6 points preoperatively to 80.4 points at final follow-up. Radiographic analysis demonstrated that the position of stems and cups was unchanged and all showed radiographic evidence of bone ingrowth.</p><p><b>CONCLUSION</b>The favourable medium-term clinical results with the cementless Zweymüller hip system show that it is suitable as a revision system for total hip failures of both cemented and cementless primary fixation.</p>

Hydrophobic interaction between beta-sheet B1 and B2 in xylanase XYNB influencing the enzyme thermostability / 生物工程学报

A homology modeling of xylanase XYNB from Streptomyces olivaceoviridis A1 was made by Swiss-Model. The hydrophobic Interaction between beta-sheet B1 and B2 in the tertiary structure model of XYNB was compared with other thermophilic xylanase. A T11Y mutation was introduced in XYNB by site-dirrected mutagenesis to improve the thermostability of the enzyme. The XYNB and mutant xylanase (XYNB') expressed in Pichia pastoris were purified and their enzymatic properties were determined. The result revealed that the thermostability of XYNB' was obviously higher than that of XYNB. The optimal temperature of XYNB' for its activity was 60 degrees C, similar to XYNB. But, compare to XYNB, the optimal pH value, the Km value and the specific activity of XYNB' had also been changed. The research results suggested that the aromatic interaction between beta-sheet B1 and B2 in xylanase should increase enzyme thermostability. The mutant xylanase XYNB' is a good material for further research in the relationship between structure and function of xylanase.

Expression of acidophilic alpha-amylase from Alicyclobacillus acidocaldarius / 生物工程学报

The alpha-amylase (EC 3.2.1.1) from the Gram-positive Alicyclobacillus acidocaldarius was one kind of thermoacidophilic enzyme, with optimal temperature and pH of 75 degrees C and 3, respectively. The nucleotide sequence of the gene amy was cloned by PCR. The gene amy was 3901bp long, comprising one open reading frame encoding a polypeptide of 1301 amino acids. The calculated molecular weight of the alpha-amylase AMY was about 140kD. The gene amy was expressed in E. coli BL21 (DE3) and Pichia pastoris respectively, and both of the cloned proteins had bioactivity. The activity of amylase expressed in P. pastoris was further testified by amylase activity staining. The alpha-amylase expressed in P. pastoris had been purified and characterized. The apparent molecular weight of that was about 160kD according to SDS-PAGE. The optimum of pH for the enzyme was pH 3.2 as the native enzyme was; but the optimum of temperature was 65 degrees C and a little lower than that of the native enzyme. Above 50% of relative activity remained after incubation for 30 minutes in 70 degrees C. So the enzyme expressed by P. pastoris was also thermoacidophilic. Moreover some sequence was cloned by PCR, which ranged from + 1174 bp to + 3288 bp in the gene amy, encoding 705 amino acids with the calculated molecular weight of 79kD. The truncated gene amy' was expressed in E. coli BL21 (DE3) induced by 1 mmol/L IPTG, and the expressed enzyme also retained alpha-amylase activity.