Vascular responses to endovascular irradiation of 188Re in the rabbit model after angioplasty

The effects on vascular restenosis of intravascular radiation delivery from ¹⁸⁸Rhenium (Re)-perrhenate liquid-filled balloon through beta-particle radiation are controversial. To determine the effect of beta-radiation on vascular injury in hypercholesterolemic rabbits, thirty rabbits fed with a high cholesterol diet were enrolled into this study. All the rabbits underwent percutaneous transluminal balloon overstretch over left iliac artery. After balloon overstretch, the catheter was withdrawn and immediately followed by irradiation using low dose ¹⁸⁸Re solution (10 Gray) in the vascular wall 0.5 mm distal to intimal surface. After 2 and 6 weeks, arteries were harvested for histological and immunological analysis. This rabbit study suggest that endovascular ¹⁸⁸Re low dose irradiation at the non-injury segment of iliac artery may enhance intima hyperplasia and smooth muscle cell proliferation.     

Dihydrogen-bond-promoted catalysis: catalytic hydration of nitriles with the indenylruthenium hydride complex (eta(5)-C(9)H(7))Ru(dppm)H (dppm = bis(diphenylphosphino)methane)

The indenylruthenium hydride complex (eta(5)-C(9)H(7))Ru(dppm)H was found to be active in catalyzing the hydration of nitriles to amides. The chloro analogue (eta(5)-C(9)H(7))Ru(dppm)Cl was, however, found to be inactive. Density functional theory calculations at the B3LYP level provide explanations for the effectiveness of the hydride complex and the ineffectiveness of the chloro complex in the catalysis. It is learned that the presence of a Ru-H.H-OH dihydrogen-bonding interaction in the transition state lowers the reaction barrier in the case of (eta(5)-C(9)H(7))Ru(dppm)H, but in the chloro system, the corresponding transition state does not contain this type of interaction and the reaction barrier is much higher. A similar dihydrogen-bond-promoting effect is believed to be responsible for the catalytic activity of the hydrotris(pyrazolyl)borato (Tp) ruthenium complex TpRu(PPh(3))(CH(3)CN)H in CH(3)CN hydration. The chloro analogue TpRu(PPh(3))(CH(3)CN)Cl shows no catalytic activity.     

The Reaction of 4-Formylsydnone and Methyl Ketones

In the presence of base, 3-subslituted 4-fonnyl- and 4-acetylsydnones decarbonylated to afford the corresponding 3-substituted sydnones. The Claisen-Schmidt reaction occurred between 3-substituted 4-for-mylsydnones and methyl ketone (such as 4-acetylsydnones, acetone and acetophenone) in dilute basic solution or electrogenerated basic (EGB) solution.     

Kinetic Studies of the Reactions of Pentacyanoferrate(II) Complexes with Peroxydisulfate

Reactions of Fe(CN)(5)L(3-) (L = 4-aminopyridine (4-ampy), pyridine (py), 4,4'-bipyridine (4,4'-bpy), and pyrazine (pz)) with peroxydisulfate, Fe(CN)(5)L(3-) + S(2)O(8)(2-) right harpoon over left harpoon Fe(CN)(5)L(2-) + SO(4)(-) + SO(4)(2-), have been found to follow an outer-sphere electron transfer mechanism. The specific rate constants of oxidation are 1.45 +/- 0.01, (9.00 +/- 0.02) x 10(-2), (5.60 +/- 0.01) x 10(-2), and (2.89 +/- 0.01) x 10(-2) M(-1) s(-1), for L = 4-ampy, py, 4,4'-bpy, and pz, respectively, at &mgr; = 0.50 M LiClO(4), T = 25 degrees C, pH = 4.4-8.8. The rate constants of oxidation for the corresponding Ru(NH(3))(5)L(2+) complexes were also measured and were found to be faster than those of Fe(CN)(5)L(3-) complexes by a factor of approximately 10(2) even after the corrections for the differences in reduction potentials and in the charges of the complexes. The difference in reactivity may arise from the hydrogen bonding between peroxydisulfate and the ammonia ligands of Ru(NH(3))(5)L(2+) and nonadiabaticity observed in the Fe(CN)(5)L(3-) complexes.     

The preparation of functional alkylidynetricobalt nonacarbonyl complexes from dicobalt octacarbonyl

Various functionally-substituted methylidynetricobalt nonacarbonyl derivatives, RCCo₃(CO)₉, where R is D, Me₃Si, PhMe₂Si, (MeO)₂P(O), (EtO)₂P(O), Me₃COC(O), Me₃SiOC(O), Et₂NC(O), CH₃C(O), C₂H₅C(O), n-C₃H₇C(O), Me₂-CHC(O), n-C₄H₉C(O), Me₃C(O), PhC(O), p-CH₃C₆H₄C(O), p-BrC₆H₄C(O), HOCH₂, HC(O), CH₃O and Me₂N, have been prepared by reaction of dicobalt octacarbonyl with the appropriate RCX₃ or RCHX₂ (XCl or Br) compound.     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

New Triterpenoid Fatty Acid Esters from the Small Twigs of Viburnum Odoratissimum

α‐Amyrin margarate ( 1 ), moretenyl margarate ( 2 ) and moretenyl palmitate ( 3 ), three triterpenoid fatty acid esters, have been isolated from the acetone extract of the small twigs of Viburnum odoratissimum in addition to the three known compounds, α‐amyrin palmitate ( 4 ), ursolic acid ( 7 ) and vibsanin‐K ( 8 ). The structures of compounds 1–3 were elucidated based on extensive spectroscopic analysis and alkaline hydrolysis. Preliminary pharmacological studies revealed that vibsanin‐K and ursolic acid exhibited significant cytotoxicity against human gastric (NUGC) and oral epidermoid (HONE‐1) tumor cells at a concentration of 50 μg/mL while compounds 1–3 were inactive.     

Depth distribution of x-rays in electron microprobe analysis

The dependence of the relative intensityk on the thin film thickness has been measured. This dependence has enabled us to verify the Monte Carlo simulation. From the experimentally determined dependence, distributions of X-rays in the specimen ((z) functions) have been derived. It has been found that the intensities calculated by the present Monte Carlo model are always higher than those measured.The authors wish to thank Prof. R. Kuel of the Faculty of Mathematics and Physics, Charles University, Prague, for the measurement of the sputtered thin films thickness.     

THE EFFECTS OF LOW DENSITY LIPOPROTEINS ON UPTAKE OF PHOTOFRIN II

The cellular uptake of Photofrin II (PII) was studied using fluorescence imaging and chemical extraction. The influence of serum and low density lipoproteins (LDL) was examined under a variety of experimental conditions employing cultured human cells of different origins as well as a subcutaneously SMT-F tumor implanted in mice. Results showed that serum inhibited PII uptake. In general, LDL also inhibits PII uptake with the exception of an initial increase in the first 10-30 min when the cellular concentration of PII was measured by fluorescence imaging instead of chemical extraction. Our results suggest a possible de-aggregation process occurring upon internalization or binding of PII to LDL.     

Pharmacokinetic study of levofloxacin in rat blood and bile by microdialysis and high-performance liquid chromatography

The aim of this study was to develop a rapid and sensitive method for the simultaneous determination of unbound levofloxacin in rat blood and bile using high-performance liquid chromatography coupled with microdialysis for further pharmacokinetic study. Microdialysis probes were simultaneously inserted into the jugular vein toward the right atrium and the bile duct of male Sprague-Dawley rats for biological fluid sampling after administration of levofloxacin 3 mg/kg through the femoral vein. Levofloxacin and dialysates were separated using a Merck LiChrospher reversed-phase C18 column maintained at ambient temperature. The mobile phase was comprised of acetonitrile-1 mM 1-octanesulfonic acid (40:60, v/v, pH 3.0 adjusted with orthophosphoric acid). The fluorescence response for levofloxacin was observed at excitation and emission wavelengths of 292 and 494 nm, respectively. The detection limit of levofloxacin was 50 ng/ml. Intra-day and inter-day precision and accuracy of levofloxacin measurements fell well within the predefined limits of acceptability. The disposition of levofloxacin in the blood and bile fluid suggests that there was rapid exchange and equilibration between the blood and hepatobiliary systems, and the plasma level of levofloxacin was greater than that of the bile. Thus, levofloxacin undergoes hepatobiliary excretion but might not be related to the P-glycoprotein transport system.