The external defibrillator is an emergency instrument used very widely in clinics. It plays an important role in rescuing ventricle fibrillation (VF) patients. We have designed an external defibrillator using the truncated exponential biphasic waveform. The system consists of three parts: the ECG collection module, the control module and the defibrillator module. They are introduced respectively, listing the main problems and the methods to solve them. Some experiments have been done and the corresponding results are given.
Animals ; Defibrillators ; Equipment Design ; Swine ; Ventricular Fibrillation

BACKGROUNDAdvances in catheter ablation procedures for the treatment of supraventricular arrhythmias have created the need to understand better the morphological and electrophysiological characteristics of the inferior nodal extension (INE) and transitional cellular band (TCB) in the atrioventricular (AV) junctional area.

METHODSFirstly, we observed the histological features of 10 rabbit AV junctional areas by serial sections under light microscopy. Then we recorded the action potentials (APs) of transitional cells (TCs) in the INE, TCBs, AV node, and ordinary right atrial myocytes from the AV junctional area of 30 rabbits using standard intracellular microeletrode techniques.

RESULTSUnder light microscopy, the INE appeared to be mostly composed of transitional cells linking upward to the AV node. Four smaller TCBs originated in the orifice of the coronary sinus, the region between the septal leaflet of the tricuspid valve and the coronary sinus, the inferior wall of the left atrium, and the superior interatrial septum, respectively, all linking to the INE or the AV node. Compared with ordinary atrial myocytes, the AP of the TCs in both the INE and the TCBs had a spontaneous phase 4 depolarization (not present in ordinary atrial myocytes), with a less negative maximum diastolic potential, a smaller amplitude, a slower maximum velocity of AP upstroke, and a longer action potential duration at 50% repolarization (APD50) and at 30% repolarization (APD30). The AP characteristics of these TCs were similar to those of the AV node, except that the velocities of the phase 4 spontaneous depolarization were slower and their action potential durations at 90% repolarization (APD90) were shorter. Moreover, APD50 and APD30 of the TCs of the TCBs were shorter than in the case of TCs of the AV node.

CONCLUSIONSThe TCs of the INE and TCBs are similar to slow response automatic cells. They provide a substrate for slow pathway conduction. In addition, repolarization heterogeneity exists in the AV junctional area.

Action Potentials ; Animals ; Atrioventricular Node ; cytology ; physiology ; Female ; Male ; Rabbits

AIMTo analyse the impurities of gatifloxacin.

METHODSThe impurity of gatifloxacin were analysized and determinated by RP-HPLC/electrospray ionization mass spectrometry with a Zorbax SB-C18(4.6 mm x 150 mm ID, 5 microns). The mobile phase was 3% acetic acid/acetonitrile-3% acetic acid/water (15:85). The two compounds were synthesized: 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-methoxy-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMP) and 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-hydro-7-(3-methy-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMO). Their liquid chromatogram, UV, MS were compared with those of the impurity of gatifloxacin.

RESULTSThe mass of the impurity was 14 less than that of gatifloxacin. It means the impurity was CH2 less than gatifloxacin. The tR (HPLC), UV and MS of DMP were the same as those of the impurity of gatifloxacin.

CONCLUSIONBased on the tR (HPLC), UV and MS, the impurity of gatifloxacin is confirmed as DMP.

Anti-Infective Agents ; analysis ; chemistry ; Chromatography, High Pressure Liquid ; Drug Contamination ; Fluoroquinolones ; analysis ; chemistry ; isolation & purification ; Molecular Structure ; Spectrometry, Mass, Electrospray Ionization

OBJECTIVETo explore the effects of bone marrow mesenchymal stem cells (MSCs) on in vitro expansion potential, the adherent molecules expression of cord blood (CB) CD34(+) cells.

METHODSMSCs were obtained from human bone marrow and their differentiation function and phenotype were identified. CB CD34(+) cells were expanded in culture systems with or without MSC layer. Hematopoietic progenitor cells and adhesion molecules expression were assessed by semisolid culture assay and flow cytometry.

RESULTSThy-1, SH2, SB10, CD44, CD13, CD49e and CD29 were highly expressed on MSCs with no expressions of CD34, CD45, HLA-DR, CD14 and CD31. The MSCs could differentiate into adipocytes and osteoblasts under specific induction conditions. After culturing on MSCs layer with supplement of cytokines for 8 days, the absolute numbers of nuclear cells, CD34(+), CD34(+)CD38(-), CD34(+)CD62L(+) cells and CFU-Cs were increased by 145.57 +/- 17.89, 37.47 +/- 13.78, 69.78 +/- 50.07, 10.74 +/- 5.89 and 20.73 +/- 5.54-folds, respectively, being significantly higher than that cultured with cytokines alone. The expression of ALCAM, VLA-alpha4, VLA-alpha5, VLA-beta1, HCAM, PECAM and LFA-1 on CD34(+) cells remained unaffected. The expressions of ICAM-1 and L-selectin were downregulated during expansion, while the absolute numbers of CD34(+)CD62L(+) and CD34(+)CD54(+) cells were increased.

CONCLUSIONSMSCs layer improves expansion of CB CD34(+) cells while inhibiting their differentiation and retaining their homing ability.

Antigens, CD34 ; Cell Adhesion Molecules ; metabolism ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Fetal Blood ; cytology ; Hematopoietic Stem Cells ; cytology ; metabolism ; Humans ; Mesenchymal Stromal Cells

OBJECTIVETo determine the protective effect of monosialoganglionside (GM1) and evaluate the influence of GM1 on expression of N-methyl-D-aspartate receptor subunit 1 (NMDAR1) in Sprague-Dawley (SD) rats with focal cerebral ischemia-reperfusion (I/R).

METHODSLeft middle cerebral artery (MCA) was occluded by an intraluminal suture for 1 h and the brain was reperfused for 72 h in SD rats when infarct volume was measured, GM1 (10 mg/kg) was given ip (intraperitoneally) at 5 min (group A), 1 h (group B) and 2 h (group C) after MCA occlusion (MCAo). Expression of NMDAR1 was detected by Western blot at various time after reperfusion (4 h, 6 h, 24 h, 48 h and 72 h) in ischemic hemispheres of the rats with or without GM1 administered.

RESULTS(1) Adjusted relative infarct volumes of groups A and B were significantly smaller than that of group C and the control group (P<0.01 and P<0.05, respectively). (2) Expression level of NMDAR1 was temporally high at 6 h after reperfusion, and dipped below the normal level at 72 h after reperfusion. GM1 at 5 min after MCAo significantly suppressed the expression of NMDAR1 at 6 h after reperfusion (P<0.05 vs the control). At 72 h after reperfusion, the NMDAR1 expression level of rats treated with GM1 administered (at 5 min or 2 h after MCAo) was significantly higher than that of the control (P<0.05).

CONCLUSIONGM1 can time-dependently reduce infarct volume in rats with focal cerebral I/R partly through stabilizing the expression of NMDAR1.

Animals ; Brain Ischemia ; metabolism ; pathology ; prevention & control ; G(M1) Ganglioside ; pharmacology ; therapeutic use ; Gene Expression Regulation ; drug effects ; Male ; Middle Cerebral Artery ; surgery ; Neurons ; drug effects ; physiology ; Protein Subunits ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Reperfusion Injury ; metabolism ; pathology ; prevention & control ; Treatment Outcome

A simple, sensitive and reliable method was developed for simultaneous determination of ten banned drugs residues including zeranols(ZALs),chloroamphenicol,pentachlorophenol,etc. in swine urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The urine samples were pretreated using lyophilization and QuEChERS procedures, respectively. Acetonitrile and ammonium acetate (5 mmol/L) were chosen as mobile phases. Target compounds were separated well in ZorbaxSB-C18by following the optimized gradient elution program and determined by LC-MS/MS in negative electrospray ionization mode. The linearity of the matrix-matched standard curve of ten analytes in two methods was good in the range of the experimental concentration with correlation coefficients more than 0.99. The recoveries of ten drugs were in the range of 80.7%-107.7% and 73.5%-103.3% at the spiked levels of 5,10 and 20 μg/L by lyophilization and QuEChERS methods,respectively. The coefficients of variation were less than 15%. The limits of detection (LOD) and the limits of quantification (LOQ) from lyophilization and QuEChERS method were 0.1 to 2.0 μg/L and 0.2 to 5.0 μg/L,respectively.

Objective To establish the three-dimensional finite element model of human lower cervical spine C3-7 motion segments after anterior cervical corpectomy and fusion (ACCF) surgery with titanium mesh and bone graft,and to analyze the stability of cervical spine and stress distribution of internal fixation devices after ACCF surgery.Methods The finite element model of cervical spine C3-7 segments after ACCF of C5 segment with titanium mesh,bone graft,plate and screw fixation was established,and C3-7 segment intact model of cervical vertebra was also constructed.The torque moment of 0.5,1.0,1.5,2.0 N · m was applied to the ACCF surgery model.The ROM,maximum stress in facet joint and stress distributions on internal fixation devices under flexion,extension,lateral bending and axial rotation movement were analyzed.Results ROM of reconstructed C5 segment increased with the torque moment increasing after ACCF surgery.In the case of 1.0 N · m tomue moment and 50 N preload,the ROM of reconstructed C5,C3-4,C6-7 and C3-7 segment was reduced by 81％,62％,58％ and 80％ compared with the intact model.The maximum stress in facet joint of reconstructed C5 segment reduced and the stress in adjacent segments significantly increased.The stress of titanium mesh was mainly distributed on the compression side of movement,and high stress was located in the roots of screws.Conclusions ACCF surgery can promote the stability of cewical spine,decrease the stress in facet joint of operation segment,and has better treatment effect on easing compression from spinal cord caused by cervical spondylotic myelopathy.The research results will provide some theoretical basis for clinical application of ACCF surgery.

Objective:To investigate the correlationship between early morning blood pressure ,brachial‐ankle artery pulse wave velocity (baPWV ) and risk factors of cardiovascular diseases (early morning blood ,blood lipid ,blood glucose , homocysteine [HCY] ,glomerular filtration rate [eGFR] ,carotid artery plaque) .Methods:Early morning blood pressure was monitored in 297 patients with primary hypertension ,and baPWV ,blood lipid ,blood glucose ,HCY ,eGFR and carotid artery color Doppler were examined .SAS 9 .2 was used to analyze the relationship between baPWV and early morning blood pressure , blood lipid ,blood glucose ,HCY ,carotid plaque and age .The independent risk factors of baPWV were analyzed by regression analysis (Stepwise) .Results:BaPWV was significantly correlated with age ,early morning blood pressure ,low density lipoprotein cholesterol (LDL‐C) ,eGFR and carotid artery plaque (P< 0 .05) .BaPWV was not significantly correlated with fasting glucose or HCY .The regression analysis showed that the early morning blood pressure ,LDL‐C and carotid artery plaque were the independent risk factors of baPWV ( P < 0 .05 ) . Conclusions: The early morning hypertension and hypercholesteremia are correlated with arteriosclerosis in patients with essential hypertension .

OBJECTIVETo investigate the incidence, risk factors, prognosis and high risk patients of invasive fungal infections (IFI) in patients with hematological diseases.

METHODS: Over 2-week hospitalized patients from January 2007 to December 2008 were retrospectively reviewed. Logistic regression was used to analyze the risk factors of IFI, and recursive partitioning to reveal high risk patients. Incidence of IFI was estimated by cumulative incidence function, and the prognosis by Kaplan-Meier method.

RESULTSA total of 1048 assessable treatment cycles were recorded and 93 cases of IFI were diagnosed, with an incidence of 8.87 per 100 treatment cycles. Multivariate logistic regression revealed the following risk factors: age (OR 1.025, 95% CI 1.010-1.041, P = 0.002), duration of neutropenia (OR 1.028, 95% CI 1.014-1.042, P < 0.0001) and uncontrolled underlying diseases (OR 2.620, 95% CI 1.608-4.268, P = 0.0001). Recursive partitioning found two groups of high risk patients: (1) patients with uncontrolled underlying diseases and neutropenia duration > or = 58 days (7/12, 58.3%), (2) patients with uncontrolled underlying diseases and age > or = 33 years (40/208, 19.2%). At the end of follow-up, 111 cases of IFI were recorded in 451 patients, with a 1-year cumulative incidence of 27.1%. In patients with established IFI, overall survival rate and IFI related mortality rate at 12 weeks after diagnosis were 83.4% and 13.5% respectively.

CONCLUSIONAge, duration of neutropenia and uncontrolled underlying diseases are risk factors of IFI; patients with uncontrolled underlying diseases and age > or = 33 years were at high risk of IFI and need major concern. IFI has a better prognosis and a lower related mortality in this study.

Female ; Hematologic Diseases ; diagnosis ; microbiology ; therapy ; Hematopoietic Stem Cell Transplantation ; Humans ; Incidence ; Logistic Models ; Male ; Multivariate Analysis ; Mycoses ; epidemiology ; Prognosis ; Retrospective Studies ; Risk Factors

Chronic myeloid leukemia (CML) at advanced and blastic phase is a disease with poor prognosis, for which allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only treatment choice with curative potential. This study was purposed to investigate the therapeutic efficacy of allo-HSCT and prognosis of advanced CML patients. The 28 cases of CML in accelerated phase or blast crisis received allo-HSCT were analysed retrospectively in terms curative efficacy, basic characteristics before transplant and prognosis, therapeutic strategy before transplant and prognosis, events after transplant and prognosis. The results indicated that 10 out of 28 patients were in complete remission, showing a 3-year overall survival and disease-free survival rate of 34.9% and 35.7% respectively; 18 patients died. Univariate analysis revealed that the clonal evolution and blast amount are baseline risk factor of poor prognosis, and combination of them can be used to predict the outcome of patients; application of imatinib before transplant and achievement of complete hematologic remission could not improve the prognosis; severe aGVHD among post-transplant events was proven to be a negative prognostic factor. It is concluded that for advanced CML patients received allo-HSCT, clonal evolution and blast percentage are prognostic factors, and the pre-transplant use of imatinib did not influence the outcome.
Adolescent ; Adult ; Benzamides ; Child ; Child, Preschool ; Female ; Hematopoietic Stem Cell Transplantation ; methods ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; drug therapy ; surgery ; therapy ; Male ; Middle Aged ; Piperazines ; therapeutic use ; Prognosis ; Pyrimidines ; therapeutic use ; Retrospective Studies ; Young Adult