Objective To investigate the protective effect of glycine (Gly) on hypoxic injury to murine cardiomyocytes and the mechanisms. Methods The survival rate of cardiomyocyte survival was detected by trypan blue exclusion and lactate dehydrogenase (LDH) with an ultraviolet spectrophotometer. Ca 2+ changes in the cardiomyocytes were detected by laser confocal microscopy. Results Glycine markedly improved the survival rate of cardiomyocytes and decreased the release of LDH in cardiomyocytes after hypoxia. The protective effect was in a dose-dependent manner. Glycine could also block calcium overload after hypoxia. Conclusion Glycine has the protective effect on cardiomyocytes through the improvement of survival rate, decrease of LDH release, and blockage of calcium overload after hypoxia.

Objectives: To explore the influence of exercise training on the arterial baroreflex sensitivity （BRS）and correlation between blood pressure and BRS in spontaneously hypertensive rats (SHR). Methods: Male SHR（n=20）and normotensive Wistar rats（n=20）were randomly assigned to normality group and exercise group, n=10 in each group. Rats in two exercise groups received treadmill training at a speed of 20 m/min for 60 min/d, 6 d/w for eight weeks. Systolic blood pressure (SBP) and heart rate (HR) were measured using a tail-cuff method in a conscious state. Intravenous injections of phenylephrine (PE) and sodium nitroprusside (NP) were used to induce depressor and pressor reflex respectively. The ratio of HR over mean arterial pressure (MAP) (HR /MAP) after administration of PE or NP was regarded as an index of depressor reflex sensitivity (BRS-PE) and pressor reflex sensivity (BRS-NP). Results: After eight-week exercise training, compared with SHR normality group, there were significant reduction in resting SBP [(180±8.5) mmHg vs. (163.6±10.7) mmHg] and in HR [(368.4±13.3) beats/min vs. (345.0±9.8) beats/min] in SHR exercise group, P<0.01 both. However, there was no significant difference in resting SBP between Wistar exercise and normality groups (P>0.05), compared with Wistar normality group, there was significant reduction in HR [(362.2 ± 13.0) beats/min vs. (343.9 ± 10.2) beats/min, P <0.05] in Wistar exercise group. Compared with SHR normality group, there were significant rise in BRS [BRS-PE: (0.89 ± 0.13) bpm/mmHg vs. (1.32 ± 0.22) bpm/mmHg, BRS-NP： (0.60± 0.09) bpm/mmHg vs. (1.21± 0.26) bpm/mmHg, P<0.01] in SHR exercise group, but still lower than those of Wistar normality group [BRS-PE: (1.96±0.23) bpm/mmHg, BRS-NP: (1.32±0.17) bpm/mmHg]. Pearson linear correlation analysis indicated that MAP was significantly inversely correlated with BRS (r=-0.734, P<0.01) in SHR normality and exercise group. Conclusion: Exercise training may significantly decrease SHR blood pressure; it is related to improved baroreflex sensitivity induced by exercise, indicating that enhanced baroreflex may be an important mechanism of exercise therapy in hypertensive patients.

Objective To investigate the changes and roles of hypoxia inducible factor 1?(HIF 1?) expression in myocardial tissues in rats following severe scald. Methods Male Wistar rats inflicted with 40% TBSA Ⅲ degree scald were used as animal models. HIF 1? protein in myocardial tissues was detected by Western blot and immunohistochemical technique. Results HIF 1? protein expression in rat myocardial tissues increased significantly in the early stage following scald. The difference in HIF 1? level between the left and right ventricles was significant. The increased HIF 1? protein was mainly located in the nucleus. Conclusion HIF 1? protein expression in myocardial tissues of rats can be induced by severe scald and HIF 1? protein expression in the left ventricle is significantly higher than that in the right ventricle. The increased HIF 1? protein in the nucleus can induce downstream cytokine expression.

Cell therapy has a very promising potential for end-stage liver diseases (ESLD).Fetal liver stem/progenitor cells (FLSPCs) have advantages of safety,high survival and proliferation rates,and a small volume,all which make them ideal for liver disease stem cell therapy.During the early phase of our study,we applied a three-step separation method to enrich FLSPCs and obtained a separation efficiency similar to that of the flow-cell sorting method.Additionally,using a fulminant hepatic failure model in rats,we have demonstrated that FLSPCs can contribute to morphological and functional recovery of the liver.This manuscript will discuss how FLSPCs can be induced to accurately differentiate into hepatocytes and cholangiocytes and how FLSPCs maintain self-renewal.The Notch signaling plays a critical role in regulating the differentiation and self-renewal of many types of stem cells.Our previous findings have shown that the Notch signaling plays an important role in FLSPCs differentiation into hepatocytes.Therefore,the Notch signaling might be involved in the differentiation and self-renewal of FLSPCs.We conducted a study on the regulatory effects and relative molecular mechanisms of the Notch signaling on FLSPCs and found the corresponding interfering target,which might become an index for the clinical application of FLSPCs.

Objective To investigate the pathogens distribution and their drug resistance of blood culture-positive neonates with sepsis in neonatal intensive care unit(NICU) and to provide evidence for clinically reasonable use of antibiotics.Methods One thousand four hundred and fifty neonates admitted to our NICU of Affiliated Hospital of Guangdong Medical College from Jan 2009 to Jul 2011 were enrolled.The blood samples from 1 450 neonates were cultured and isolated,and all of the isolates and their resistances were analyzed retrospectively.Results A total of 9 species and 233 pathogenic strains were isolated from 1 450 specimens,and the positive rate was 16.1％.Among the 233 strains,93 strains were gram-positive cocci,103 strains were gram-negative bacilli,and 37 strains were fungus.Among gram-positive cocci,the most dominant organism was coagulase negative staphylococcus,the next was Staphylococcus aureus;while among gram-negative bacilli,Ktebsiella pneumoniae were the most frequently isolated,the next were Escherichia coli and Acinetobacter baumannii,and among the fungus,monilia were the most isolated.The resistance rates of gram-positive cocci to vancomycin,linezolid and teicoplanin were high.Moreover,the antibiotic resistance rates to penicillin,oxazocilline and the β-lactamase were more than 95％.Gram-negative bacilli were sensitive to levofloxacin,imipenem and meropenem.A majority of fungus was Monilia,which was sensitive to antifungal.Conclusion Coagulase negative staphylococcus,Klebsiella pneumoniae and Escherichia coli are the the most common pathogens of neonatal sepsis in NICU,and have high drug resistance.Clinicians should select sensitive drug treatment according to bacterial identification and susceptibility testing.Besides,mycotic infection cannot be ignored and merit our attention.

OBJECTIVE Through the investigations of the pathogen monitoring and drug resistance,we find the evidence for controlling the spread of bacterial drug resistance.METHODS The medical hospital of 1180 patient cases frim 2005 to 2007 were retrospectively investigated and analyzed.RESULTS For recent two years there were isolated 170 strains of pathogenic bacteria and the top five were Pseudomonas aeruginosa,Staphylococcus epidermidis,Candida albicans,Staphylococcus aureus and Escherichia coli.P.aernuginosa was in the first place and its drug rssistance was severe.The sensitive ratio of MRSA and MRCNS to vancomycin was 100% and their resistance ratio to oxacillin,penicillin,amoxicillin/clavulanic acid and ampicilin/sulbactam was 100%;The E.coli and in ESBLs-producting Klebsiella pneumoniaehad multidvug vesistance to various kinds of antibacterials.CONCLUSIONS The resistance of the pathogenic bacteria is increasing year by year,and the multi-drug resistance is also seen,we should use the antibiotic properly in clinicsl to control the increase in bacterial drug resistance.

OBJECTIVETo explore the effects of microtubule depolymerization (MD) on the spontaneous beating rate, action potential (AP), and oxygen consumption of cardiac myocytes in rats and its mechanism.

METHODSOne-hundred and eighty neonatal SD rats divided into 12 batches were used in the experiment, and 15 rats in each batch were sacrificed for the isolation and culture of cardiac myocytes after the heart tissues were harvested. The cardiac myocytes were respectively inoculated in one 12-well plate filled with 6 round cover slips, one 12-well plate filled with 6 square cover slips, two cell culture flasks, and two cell culture dishes. After routine culture for three days, the cardiac myocytes from all the containers were divided into normal control group (NC, routinely cultured with 3 mL DMEM/F12 solution rewarmed at 37 °C for 3 h) and group MD (routinely cultured with 3 mL DMEM/F12 solution rewarmed at 37 ° and containing 8 µmol/L colchicine for 3 h) according to the random number table, with 3 holes, 1 flask, or 1 dish in each group. The morphological changes in microtubules were observed with confocal laser scanning microscope after immunofluorescent staining. The content of polymerized or dissociative α-tubulin was determined by Western blotting. Spontaneous beating rate of the cells was observed and calculated under inverted microscope. Dissolved oxygen concentration of DMEM/F12 solution containing cardiac myocytes was determined by oxygen microelectrode system before and after the addition of colchicine. Additionally, dissolved oxygen concentration of DMEM/F12 solution and colchicine + DMEM/F12 solution was determined. The whole-cell patch-clamp technique was used to record AP, delayed rectifier K+ current (I(K)), and L-type Ca2+ current (I(Ca-L)) in cardiac myocytes; current density-voltage (I-V) curves were drawn based on the traces. Data were processed with independent or paired samples t-test.

RESULTS(1) In group NC, microtubules of cardiac myocytes were around the nucleus in radial distribution with intact and clear linear tubiform structure. The microtubules in group MD were observed in dispersive distribution with damaged structure and rough linear tubiform structure. (2) In group MD, the content of dissociative α-tubulin of cells (0.61 ± 0.03) was obviously higher than that in group NC (0.46 ± 0.03, t = -6.99, P < 0.05), while the content of polymerized α-tubulin (0.57 ± 0.04) was significantly lower than that in group NC (0.88 ± 0.04, t = 9.09, P < 0.05). (3) Spontaneous beating rate of cells was (59 ± 8) times per min in group MD, which was distinctly higher than that in group NC [(41 ± 7) times per min, t = 5.62, P < 0.01]. (4) Dissolved oxygen concentration of DMEM/F12 solution containing cardiac myocytes was (138.4 ± 2.5) µmol/L, and it was reduced to (121.7 ± 3.6) µmol/L after the addition of colchicine ( t = 26.31, P < 0.05). There was no obvious difference in dissolved oxygen concentration between DMEM/F12 solution and colchicine + DMEM/F12 solution (t = 0.72, P > 0.05). (5) Compared with that of group NC, AP morphology of cells in group MD changed significantly, with unobvious repolarization plateau phase and shorter action potential duration (APD). The APD20, APD50, and APD90 were respectively (36.2 ± 3.8), (73.7 ± 5.7), and (115.1 ± 8.0) ms in group MD, which were significantly shorter than those of group NC [(40.2 ± 2.3), (121.4 ± 7.0), and (169.4 ± 5.6) ms, with t values respectively 2.61, 15.88, and 16.75, P values below 0.05]. (6) Compared with that of group NC, the I-V curve of I(K) of cells in group MD moved up with higher current density under each test voltage (0 to 40 mV) after activation ( with t values from 2. 70 to 3. 76, P values below 0.05) . (7) There was not much alteration in current density of I(Ca-L) under each test voltage (-30 to 50 mV) between 2 groups (with t values from -1.57 to 1.66, P values above 0.05), and their I-V curves were nearly overlapped.

CONCLUSIONSAfter MD, the I(K) is enhanced without obvious change in I(Ca-L), making AP repolarization faster and APD shortened. Then the rapid spontaneous beating rate increases oxygen consumption of cardiac myocytes of rats.

Action Potentials ; Animals ; Cells, Cultured ; Energy Metabolism ; Microtubules ; metabolism ; Mitochondria, Heart ; metabolism ; Myocytes, Cardiac ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tubulin ; metabolism

Objective To explore the possible effects of hepatocyte growth factors (HGF) on prevention and therapy of disused gastrocnemius atrophy in rats by observing their effects on the wet weight and contractile function of the gastrocnemius of fixed hind limbs. Methods Twenty-four Wister male rats were randomly divided into a blank group, a contrast group and an experimental group. Their right hind limbs were fixed for four weeks with plastic piaster from metatarsus to 1 cm up the knee. Their knee joint was fixed in 100?flexion and their ankle joint in 60?plantar flexion. Rats in the contrast group were injected with 0. 2 mL of normal saline, and rats in the ex- perimental group were injected with HGF (10 mg/kg, 10 mg/mL). Their whole gastrocnemius of the right hind limb was dissected four weeks later to measure its contractile function and wet weight. Results Compared with the blank group, single maximal contraction, maximal tetanus, and wet weight of the gastrocnemius in the contrast and experimental groups decreased significantly (P＜0. 05), and fields of electric stimulation also decreased signifi- cantly (P＜0. 05). Compared with the contrast group, single maximal contraction, maximal tetanus, and wet weight of the gastrocnemius in the experimental group were significantly superior (P＜0.05), and fields of electric stimulation significantly increased. Conclusion Since after a local injection of HGF, the contractile function and wet weight can be significantly increased, HGF may have a preventive effect on disused atrophy.

Ion trap performances are investigated based on digital ion trap technique with different collision gases at different pressures. Collision gases of helium (4 amu), nitrogen (28 amu) and argon (40 amu) with various pressures are adopted in ion excitation and dissociation stages to investigate the ion trap performances, including mass resolution, signal intensity, tandem mass spectrometric analysis ability and low-mass cut off (LMCO) effect. It is found that when heavy gas of argon is used, energy can be efficiently transferred and LMCO effect is decreased with higher ion capture and dissociation efficiencies but with low mass resolution. Higher mass resolution is realized with helium as collision gas. Furthermore, at the same gas pressure, heavy gas is beneficial to abundant fragment ions and structural information of precursor ion.

Objective To compare the scores of amplitude-integrated electroencephalogram (aEEG) tracings between preterm infants who were smaller for gestational age (SGA) and those who were appropriate for gestation (AGA).Methods A total of 139 preterm infants were collected in the Neonatal Intensive Care Unit of the Affiliated Hospital of Guangdong Medical College during the period of Mar.2013 to Feb.2014.One hundred and fourteen patients met the inclusion criteria with gestational ages from 32 to 36 weeks at birth,including 54 SGA infants and 60 AGA infants.The aEEG recordings were obtained within 72 h after birth by using the NicoletOne monitor.Duration of each recording was at least 3 h.Five aspects of each tracing,such as continuity (Co),sleep-wake cycling (Cy),amplitude of the lower border (LB),bandwidth (B) and total maturation scores,were evaluated and compared between 2 groups by applying a aEEG scoring system.Results 1.As SGA infants,scores for Co,Cy,LB,B as well as total maturation scores were progressively increased with gestational age advancing(all P ＜ 0.05).As AGA infants,scores for Cy,B and total maturation scores progressively increased with advancing gestational age (all P ＜ 0.05),but there were no statistical differences between each gestational ages in Co,LB scores (all P ＞ 0.05).2.Linear regression analysis of SGA infants' gestational age to Co,Cy,LB,B and total maturation scores showed positively correlation,and the correlation coefficients were 0.438,0.597,0.385,0.606 and 0.608,respectively (all P ＜ 0.05).As AGA infants,a positive correlation between gestational age and Cy,B as well as total maturation scores were observed,and the correlation coefficients were 0.528,0.615 and 0.635,respectively (all P ＜ 0.05).3.At the same gestational age,both the B scores and total maturation scores in SGA group were lower than those in AGA group.Conclusions SGA and AGA,Co,Cy and total maturation scores can be used to evaluate the maturation of cerebral function.At the same gestational age,the scores of B and total maturation scores are lower in the SGA,and this might be associated with their delayed neuromotor development.