Objective:To obtain a large amount of erythromycin B and to investigate the activity site in eryK. Methods:The key sequence of the BC loop region in eryK gene was knocked out and the eryK gene with 101 bp deleted was amplified by overlapping PCR,and cloned into vector pWHM3 to construct recombinant plasmid. The Saccharopolyspora erythraea mutant AK17 was constructed through chromosomal homologous recombination technique.Results and Conclusions:The S.erythraea mutant AK17 was constructed. The results of TCL and MS analysis showed that the major fermentation product of AK17 is erythromycin B.

Objective: To verify whether there exists melatoni n(Mel) receptor in human embryonic nervous system. Methods: Spec ific binding of Mel to embryonic brain and spinal cord was measured by radioliga nd binding assay. Results: 125　I-Mel binding s ites in optomeninx was the most, in eptochiasm and sniff ball was next; GTPγS d ose-de pendently inhibited the binding. Conclusion: The results demonst rate the presence of specific binding of Mel in human embryonic brain and spinal cord. GTPγS has some effect on 125　I-Mel specific binding,support ing the theory that Mel receptor is coupled to inhibitory G-proteins.

OBJECTIVETo investigate the protective effects of sildenafil to noise-induced hearing loss in guinea pigs.

METHODSGuinea pigs were randomly divided into control group, noise exposure group and the sildenafil treatment group, with 10 in each group. One week after the exposure of 110 dB (A) white noise, sildenafil [10 mg/(kg×d)] and normal saline [4 ml/(kg×d)] were injected into guinea pigs of noise plus sildenafil group (NSG) and noise plus normal saline group(NNG) respectively. One week after noise exposure to four weeks continuous administration. ABR thresholds were measured respectively prior to the experiment, 1 week post-noise, 1, 2 and 4 weeks post-drugs. The changes of cochlea hair cells were also observed by scanning electron microscope (SEM).

RESULTSAfter noise exposure, the ABR threshold shifts in NSG were significantly fewer than that in the NNG. An average of 19.1 dB in NNG compared with 19.8 dB in NSG. Four weeks after exposure, the threshold shifts were become larger to 22.0 dB in NNG while become smaller to 4.8 dB in NSG. Compared NNG with NSG, in addition to noise exposure time point, there were statistically significant differences in the rest time points after administration of the ABR threshold (P<0.05). SEM showed that the inner and outer hair cells in NNG displayed mess, fusion and imperfections. In NSG, the hair cells displayed slight pathological changes, there was no significant difference when compared with control group.

CONCLUSIONSildenafil is able to reduce the ascending of ABR thresholds shift, and it can significantly protect against noise-induced hearing loss.

Animals ; Auditory Threshold ; drug effects ; Cochlea ; drug effects ; Guinea Pigs ; Hair Cells, Auditory ; drug effects ; Hearing Loss, Noise-Induced ; physiopathology ; Piperazines ; pharmacology ; Purines ; pharmacology ; Sildenafil Citrate ; Sulfones ; pharmacology

At present,the unrealistically high drug prices become an indisputable fact to cause the chaos in the medical field.They are the main reasons of "difficult and too expensive to see doctors".And they are deeply loathed by the people in the country.In addition,the unrealistically high drug prices have become the shackles in deepening medical and health reform.Therefore,a determined effort must be made to resolve the serious problems.Through analyzing the status of high drug prices,the main reasons of the unrealistically high drug prices,and the hazards of high drug prices,the article puts forward countermeasures of state monopoly in national essential drugs to solve the unrealistically high drug prices problems for structural reform of supply side.

AIMOn the model of limb ischemia/reperfusion (LIR), the effects of taurine on pulmonary morphological changes in rats were observed.

METHODSWistar rats were divided into three groups (n=8): control group, ischemia/reperfusion group (IR) and taurine + IR (Tau + IR). Then macroscopic inspection and optical and transmission electron microscopies (TEM) were performed to assess the morphological changes of the lung tissues and their lung index (LI) and lung permeability index (LPI) and reactive oxygen species (ROS), malondialdehyde (MDA) were measured as well.

RESULTSThe morphological changes of lung tissue after LIR were characterized by an increase of permeability of the alveoli-capillary membrane and infiltration of inflammatory cells. Under optical microscopy, there were congestion and swelling in pulmonary microvessels with broadened the spaces around the blood vessels. Under TEM, a number of tight-junctional regions between adjacent alveolar epithelial cells and between pulmonary microvessels endothelium were "open". The LI, LPI, MDA and ROS increased. The specimens of Taurine + IR group revealed slight to moderate degrees of damages in the lung tissues.

CONCLUSIONTaurine protects lung from LIR in rats and the protective action on tight-junctional regions between cells and anti-oxygen is one of the protective mechanisms of taurine.

Animals ; Hindlimb ; blood supply ; Lung ; drug effects ; pathology ; Lung Injury ; prevention & control ; Male ; Malondialdehyde ; analysis ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; analysis ; Reperfusion Injury ; prevention & control ; Taurine ; pharmacology ; Tight Junctions ; metabolism

Cardiac Catheterization ; Heart Septal Defects, Ventricular ; therapy ; Humans ; Prosthesis Implantation ; instrumentation ; Septal Occluder Device

OBJECTIVETo define the effects of Astragalus membranaceus on the atrial dynamics and ANP secretion in the perfused beating rabbit atria.

METHODThe experiments have been done in isolated perfused beating rabbit atria. ANP was measured by radioimmunoassay in the atrial perfusate in real-time base.

RESULTA. membranaceus (2.0, 2.5, 3.0 g L(-1)) could increase atria stroke volume from (694.70 +/- 0.01) microL g(-1) (P<0.05) to (1,003.00 +/- 8.80) microL g(-1) (P<0.001); (1,120.00 +/- 17.71) microL g(-1) and (1,195.00 +/- 8.21) microL g(-1) (P<0.001), respectively, and its could difference increase atrial pulse pressure from (0.82 +/- 0.01) kPa to (0.86 +/- 0.01) kPa (P<0.01); (0.96 +/- 0.01) kPa (P<0.001) and (1.02 +/- 0.01) kPa (P<0.001), respectively; A. membranaceus obviously increased rabbit atrial dynamics with dose-dependent manner. Simultaneously, A. membranaceus inhibited ANP secretion. Nifedipine (1.0 micromol L(-1)), a L-type Ca2+ channel inhibitor, and KB-R 7943 (10.0 micromol L(-1)), an inhibitor of reversed Na+ -Ca2+ exchanger, blocked the effects of A. membranaceus-induced augmentation of atrial dynamics but failed to modulation the inhibition of A. membranaceus on ANP secretion.

CONCLUSIONA. membranaceus increases the atrial dynamics via Na+ -Ca2+ exchanger and L-type Ca2+ channel and negatively modulates ANP secretion in beating rabbit atria.

Animals ; Astragalus membranaceus ; chemistry ; Atrial Natriuretic Factor ; metabolism ; secretion ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Female ; Heart Atria ; drug effects ; metabolism ; secretion ; Male ; Myocardial Contraction ; drug effects ; Nifedipine ; pharmacology ; Rabbits ; Radioimmunoassay ; Thiourea ; analogs & derivatives ; pharmacology

Xi'an Jiaotong University has proposed the concept of "less teaching and more learning, interaction between guiding and learning" in medical education, based on its sedimentary deposits, and carried out reform for all clinical medical students since 2001. After more than ten years of educational reform, we have built brand new management framework, and established integrated organ system-based curriculum and PBL teaching pattern. This pattern involves eight aspects of comprehensive reform, including training program, curriculum model, textbook, teaching method, learning style, assessment and evaluation, teaching organization, teaching conditions and guarantee. It will provide paradigm for the integrated curriculum reform in peer colleges, and will be a milestone in the history of medical education in China.

On a model of reperfusion after ischemia in the hind limbs (LIR) of rats, we used aminoguanidine (AG) which inhibits nitric oxide synthase (NOS) and L-arginine (L-Arg), one of the substrates in the process of nitric oxide synthesis, to observe the changes in NO, NOS, malondialdehyde (MDA), myeloperoxidase (MPO) and wet/dry ratio (W/D) in both skeletal muscles and the lung as well as the changes in phosphatidyl choline (PC) of lung surfactant. The morphologic changes were observed with microscopy. It was observed that the values of NOS, MPO, MDA of the muscle and lung in LIR group increased significantly and the content of PC decreased obviously compared with those of the normal control. Pulmonary observation revealed that after LIR leucocyte assembling and infiltration took place, which was dominated by polymorphocytes with broadened pulmonary interstitial tissue. In LIR+L-Arg group the above changes were reversed, and in LIR+AG group the injuries became more serious. The results obtained suggest that the activity of NOS and the production of NO following ischemia/reperfusion of hind limbs increased significantly, and that the endogenous NO may play a protective role during the early stage of acute lung injury after LIR.
Animals ; Hindlimb ; Lung Diseases ; etiology ; metabolism ; pathology ; Male ; Nitric Oxide ; metabolism ; physiology ; Nitric Oxide Synthase ; metabolism ; Rats ; Rats, Wistar ; Reperfusion Injury ; metabolism

OBJECTIVETo investigate the feasibility of reconstruction of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) with hamstring tendons knot implant fixation.

METHODSFifty-two cases of ACL and PCL old injury were reconstructed under the arthroscopy with double bundles hamstring tendons knot implant fixated in the bottle-necked femoral tunnel. The tibia side were fixated by tendon weave suture cross tied a knot at the bone bridge of tibia. In this group reconstruction of ACL was in 25, PCL and ACL at the same time reconstruction in 15, PCL in 12. The failure test and displacement evaluation were used to study the biomechanics of reconstruction of ACL by hamstring tendon knot implant fixation (n = 13) in porcine knees. The control group were reconstructed with bone-patellar tendon-bone B-PT-B and interference screw (n = 11). The tibia side tendon weave suture immobility by cross tied a knot at the tibia bone bridge (n = 7) and interference screw in the tibia tunnel (n = 8).

RESULTSForty-nine cases were followed up, average 14.6 months. The results of Lanchman test was negative in 46 cases, positive in 3 cases. Preoperative Lysholm score was 56.7, and postoperative was 92.8. According to the knee joint effective evaluate standard, 46 were excellent and 3 good. The maximal pull-out force of hamstring tendons knot implanted fixation had been greater than B-PT-B fixation by interference screw. There were similar displacement in 100 N and 400 N load between hamstring tendons knot implant fixation and B-PT-B (P > 0.05). Peak force test maximal displacement evaluation and failure energy absorption measurement showed that hamstring tendons knot implant fixation was significantly greater than B-PT-B (P < 0.01). The failure test and displacement evaluation of tendon fixation by weave suture knot at the tibia bone bridge cross tie were greater than B-PT-B fixation by interference screw.

CONCLUSIONThe methods of reconstruct of ACL and PCL by hamstring tendons knot implant fixation are feasible. The advantages include: it is biological fixation, not machine fixation; it may benefit for tendons with bone tunnel healing and decrease medical cost. Decreasing or eliminating displacement is helpful to prevent relaxation after reconstruction of ACL and PCL.

Animals ; Anterior Cruciate Ligament ; surgery ; Anterior Cruciate Ligament Injuries ; Biomechanical Phenomena ; Female ; Follow-Up Studies ; Humans ; Knee Injuries ; surgery ; Male ; Orthopedic Procedures ; methods ; Posterior Cruciate Ligament ; injuries ; surgery ; Swine ; Tendons ; surgery