The study aims to identify the degradation products of levofloxacin by HPLC-MS. The degradation products of levofloxacin were chromatographed on Agilent Zorbax Extend-C18 column (250 mm x 4.6 mm, 5 microm). The mobile phase was 0.1% ammonium acetate solution (using methanoic acid to adjust to pH 3.5)-acetonitrile at the flow rate of 0.5 mL x min(-1) (gradient elution), the column temperature was 40 degrees C. Descarboxyl levofloxacin, desmethyl levofloxacin and levofloxacin N-oxide were identified through comparing with the standard spectrum and the results of mass spectrometry, i.e. m/z 318.2 was descarboxyl levofloxacin, m/z 348.2 was desmethyl levofloxacin, m/z 378.1 was levofloxacin-N-oxide. This method is simple, fast, accurate and suitable for the identification of degradation products of levofloxacin.
Chromatography, High Pressure Liquid ; methods ; Drug Stability ; Levofloxacin ; Mass Spectrometry ; methods ; Ofloxacin ; analysis ; chemistry ; Photolysis

Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.
Air Pollutants/chemistry/metabolism ; *Environmental Exposure ; Environmental Remediation ; Food Chain ; Humans ; Mercury/chemistry/*metabolism ; Methylmercury Compounds/chemistry/metabolism ; Photolysis ; Sulfur-Reducing Bacteria/metabolism ; Water Pollutants, Chemical/metabolism

BACKGROUND/AIM: Abnormality in GB motility is related with many gallbladder diseases including GB stone. Gallbladder motility is controlled by both hormonal and neural mechanisms. CCK, gastrin, motilin play a role on gallbladder contraction and VIP, somatostatin are inhibitory agents. Nitric oxide(NO) is known to account for the biologic properties of endothelium dependant relaxing factor. It also plays an important role in mediation of relaxation in various types of non-vascular smooth muscle of GI tract. The objective of this study was to determine the effect of nitric oxide in human gallbladder muscle. METHOD: In this study, nitric oxide was generated by photolysis using long wave-length UV lamp(366 nm) on NO carrying molecule, streptozotocin. GB muscle strips were obtained from 10 cholecystectomized patients and contracted by potassium or CCK-8. We also investigated the effect of methylene blue, which is a inhibitor of guanylate cyclase, after addition of methylene blue to the organ bath containing streptozotocin. Gallbladder movements were recorded using Polygraph(Grass model 79E, USA). And we identified the production of nitric oxide using nitrite assay in our No generating system. RESULTS: 1. Streptozotocin, No containing compound, released NO when UV irradiated. The longer UVR and the higher concentration of STZ, the larger is the amount of produced NO. 2. The human GB muscle was relaxed immediately by photo-induced NO and rapidly disappeared. The maximal relaxation under STZ, 60 sec UVR was 23.1 % comparing potassium or CCK induced contraction. 3. The relaxation was significantly inhibited by methylene blue, the inhibitor of gualylate cyclase. CONCLUSION: According to above results, we confirmed that nitric oxide relaxed human gallbladder muscle. And we think that the further study should be done to examine whether the L-arginine/NO pathway exist in human GB.
Baths ; Endothelium ; Gallbladder Diseases ; Gallbladder* ; Gastrins ; Gastrointestinal Tract ; Guanylate Cyclase ; Humans ; Methylene Blue ; Motilin ; Muscle, Smooth ; Negotiating ; Nitric Oxide* ; Photolysis ; Potassium ; Relaxation ; Sincalide ; Somatostatin ; Streptozocin

The mechanism underlying the bladder relaxation during filling is not fully understood. Nitric oxide played an important role in mediation of relaxation in between vascular and various types of non-vascular smooth muscle. Theoretically, an increased activity of nitric oxide-releasing inhibitory nerves to the detrusor could be a factor keeping the bladder relaxed during the filling phase. The role of nitric oxide in detrusor muscle is still not fully characterized. The objective of this study was to determine the effect and action mechanism of nitric oxide in the rat detrusor. In this experiment, nitric oxide was generated by photolysis using a long wavelength UV lamp ( 366nm) under nitric oxide, NO2-carrying molecules( streptozotocin, NG-nitro-L-arginine). This study were consisted of in vitro examination using Polygraph(Grass Model 79E, Quincy, MA, U.S.A.), radioimmunoassay for guanosine 3', 5'-cyclic monophosphate and nitrite assay to identify the production of nitric oxide. Nitric oxide was generated by photolysis from nitric oxide and NO-containing compounds. The longer UV irradiated and the stronger photo energy of light source, the more produced the amount of nitric oxide. The relaxation induced by nitric oxide-containing compound ( streptozotocin) is much more than that by NO2-containing compound(NG-nitro-L-arginine). Nitric oxide was a potent but labile relaxing substance to the rat detrusor strip. The maximal relaxation under streptozotocin treatment and 60 second UV irradiation was approximately 70.0 % comparing to carbachol induced contraction. That relaxation was significantly inhibited by pyrogallol, methylene blue treatment. The photo-induced nitric oxide directly activated soluble form of guanylate cyclase resulting in increased concentration of guanosine 3' 5'-cyclic monophosphate in detrusor strips. From the above results. it was confirmed that nitric oxide relaxed the detrusor muscle, which means that L-arginine/nitric oxide pathway may be present in the mechanism of relaxation. Therefore, new therapeutic approach using exogenous nitric oxide will be an attractive modality in treating functional voiding disturbances such as detrusor hyperreflexia and bladder instability.
Animals ; Carbachol ; Guanosine ; Guanylate Cyclase ; Methylene Blue ; Muscle, Smooth ; Negotiating ; Nitric Oxide* ; Photolysis* ; Pyrogallol ; Radioimmunoassay ; Rats* ; Reflex, Abnormal ; Relaxation ; Streptozocin ; Urinary Bladder

To study the photo-degradation products of 1-[1-(6-methoxy-2-naphthyl) ethyl]-2-(4-nitrobenzyl)-6,7-dimethoxyl-1,2,3,4-tetrahydroisoquinoline hydrobromide (code designation: P91024). The chemical structures of the major photo-degradation products of P91024 were identified by HPLC-MS and spectroscopic methods, and their reference substances were also synthesized for confirmation. The three major photo-degradation products were identified to be N-(4-nitrobenzyl)-6,7-dimethoxyl-3, 4-dihydroisoquinoline bromide, 1-[1-(6-methoxyl-2-naphthyl) ethyl]-6, 7-dimethoxyl-1, 2, 3, 4-tetrahydroisoquinoline and 2-isopropyl-6-methoxyl-naphthalene, respectively.
Chromatography, High Pressure Liquid ; methods ; Fibrinolytic Agents ; chemistry ; Molecular Structure ; Photolysis ; Quality Control ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tandem Mass Spectrometry ; methods ; Tetrahydroisoquinolines ; chemistry

OBJECTIVETo determine the visible light-induced photodegradation kinetics of two xanthene photosensitizers, phloxine B and uranine, in solution and on the surface of silica TLC plates, and to examine the phototoxicity of residues of degradation, which could provide valuable safety data on the two photosensitizers and other xanthene chemicals when applied in the environment.

METHODSUV-Vis absorption during photodegradation was monitored with a Unico 2102 spectrophotometer. Organic content of samples was measured with a Shimadzu TOC 4100. Phototoxicity tests were carried out using Saccharomyces cerevisiae with the methods modified from Daniels.

RESULTSWhen phloxine B and uranine degraded in solution, their apparent rate constant k was 0.0019 and 0.0027 min(-1), respectively. The total organic carbon (TOC) content decreased by approximately 50% during the 8 h irradiation period, which led to a gradual decrease in phototoxicity of the residues. The photodegradation of photosensitizers on the surface of silica TLC plates was much faster than that in the solution. The apparent rate constant k and the half life of phloxine B were 0.0073 min(-1) and 95 min, respectively.

CONCLUSIONVisible light can rapidly induce photodegradation of phloxine B and uranine. The phototoxicity of residues is also decreased. The environmental risk of applications of phloxine B and uranine is minimal.

Eosine I Bluish ; chemistry ; toxicity ; Fluorescein ; chemistry ; toxicity ; Kinetics ; Molecular Structure ; Photolysis ; Photosensitizing Agents ; toxicity ; Saccharomyces cerevisiae ; drug effects ; radiation effects

Although bulk endocytosis has been found in a number of neuronal and endocrine cells, the molecular mechanism and physiological function of bulk endocytosis remain elusive. In pancreatic beta cells, we have observed bulk-like endocytosis evoked both by flash photolysis and trains of depolarization. Bulk-like endocytosis is a clathrin-independent process that is facilitated by enhanced extracellular Ca(2+) entry and suppressed by the inhibition of dynamin function. Moreover, defects in bulk-like endocytosis are accompanied by hyperinsulinemia in primary beta cells dissociated from diabetic KKAy mice, which suggests that bulk-like endocytosis plays an important role in maintaining the exo-endocytosis balance and beta cell secretory capability.
Animals ; Calcium ; metabolism ; Cytoplasmic Granules ; metabolism ; Diabetes Mellitus ; metabolism ; pathology ; Disease Models, Animal ; Dynamins ; metabolism ; Electric Capacitance ; Endocytosis ; physiology ; Insulin ; metabolism ; Insulin-Secreting Cells ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Patch-Clamp Techniques ; Photolysis ; Primary Cell Culture