To set up a new method of detecting bacterial number in situ,NADH fluorescence method based on the fluorescent characteristic of NADH was used.When the concentration of NADH ranged from 10 nmol/L to 0.2 mmol/L,its concentration had a good line relationship to the fluorescence intensity(R2= 0.9905).Separating bacterial cells by centrifugation and extracting NADH with hot Tris-HCl buffer,the re-sult of bacterial count detected with NADH standard plot was 1?104 CFU/mL in an hour.In summary,NADH fluorescence method is rapid,sensitive,simple and reliable to detect total bacterial number.There-fore,the method can be widely applied in the field of food sanitation and safety,environment detection and so on.

AIMTo observe the differences of hemodynamics and nitric oxide synthase(NOS) activity of ventricular cardiac muscle in two septic shock models and explore the possible mechanism.

METHODSTwo rat models of septic shock[lipopolysaccharide(LPS)-induced and cecal ligation and puncture (CLP)-induced septic shock] were used. The hemodynamic parameters and nitric oxide synthase activity of ventricular cardiac muscle were measured.

RESULTSThe hemodynamic parameters in CLP-induced model were increased in the early stage and decreased in the late stage while in LPS-induced model the parameters showed the same change of the CLP late stage. Both LPS model and CLP model (late stage) showed significant increase in NOS activity, but there was no difference between the two models. After treatment of the NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME), the parameters of CLP-late stage and LPS model increased significantly. The NOS activity reached the highest level in the CLP-middle stage. The production of nitrite/nitrate decreased significantly in LPS model and CLP model(late stage) after treatment of L-NAME, but the nitrite/nitrate produced by constitutive NOS in LPS model was higher than CLP model(late stage).

CONCLUSIONThe increase of the NOS activity may be the main reason to lead to the depression of the hemodynamic parameters. Inducible NOS may play the leading role in the LPS model while cNOS and iNOS have the same effect in the CLP model.

Animals ; Hemodynamics ; Lipopolysaccharides ; Male ; Myocytes, Cardiac ; metabolism ; Nitric Oxide Synthase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Shock, Septic ; classification ; metabolism

AIMTo investigate the effect of three types of nitric oxide synthase inhibitors on the changes of hemodynamic parameters and thoracic aorta tension induced by septic shock in rats.

METHODSWe used cecal ligation and puncture (CLP) method to establish septic shock in rats, and the three types of nitric oxide synthase inhibitors were injected after CLP. The carotid artery was cannulated and connected to a pressure transducer to determine mean arterial blood pressure (MABP). Ventricular dynamic parameters were determined following intraventricular cannulation via the carotid artery, including heart rate (HR), left ventricular developed pressure (LVDP), maximal rise/fall velocity of ventricular pressure (+/- dP/dt(max)). Isolated thoracic rings were mounted on an organ bath and the tension of the vessel was recorded.

RESULTS(1) After using L-NAME, AMG and 7-NI the mortality decreased to 50.0%, 37.5%, and 42.1%, respectively (from 65.2% in septic shock rats); (2) The MABP in septic shock rats partly recovered after using the NOS inhibitors, all ventricular dynamic parameters partly recovered after using the inhibitors; (3) The hyporeactivity of endothelium-denuded aortic rings to vasoconstrictors induced by septic shock was partly recovered by pretreatment with the inhibitors. However, only L-NAME or 7-NI could inhibit the decrease of vasoconstriction induced by septic shock in endothelium-intact aortic rings.

CONCLUSIONThe three types of nitric oxide synthase inhibitors can improve the hemodynamic parameters and vasoconstriction responsiveness of endothelium-denuded aorta of septic shock rats. Furthermore, L-NAME and 7-NI improve the responsiveness of endothelium-intact aorta.

Animals ; Aorta, Thoracic ; physiopathology ; Enzyme Inhibitors ; pharmacology ; Hemodynamics ; drug effects ; Indazoles ; pharmacology ; Male ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide Synthase ; antagonists & inhibitors ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Shock, Septic ; physiopathology