The disordering effect of hyoscyamine drugs on phospholipid membranes.

The effect of hyoscyamine drugs on the fluidity of dipalmitoylphosphatidylcholine liposomes has been studied by differential scanning calorimetry (DSC), electron spin resonance spectroscopy (ESR), fluorescence polarization and freeze-fracture electron microscopic techniques. DSC results indicate that anisodamine, anisodine, atropine and scopolamine all increase the fluidity of dipalmitoylphosphatidylcholine liposomes but with different degrees of efficiency. The increasing of fluidity of dipalmitoylphosphatidylcholine liposomes by hyoscyamine drugs is in a dose-dependent way. Increase of the fluidity of phosphatidylcholine liposomes by anisodamine was also shown by the other three methods. The possible mechanism of hyoscyamine-membrane interaction is discussed.

Anisodamine induces the hexagonal phase in phospholipid liposomes.

The effects of anisodamine on the polymorphic phase behaviour of cardiolipin and dioleoylphosphatidylcholine liposomes have been investigated by freeze-fracture electron microscopy. Anisodamine induces the formation of lipidic particles in cardiolipin liposomes at pH 7.0 and hexagonal HII tubes at pH 8.8. When the molar ratio of anisodamine and dioleoylphosphatidylcholine is 4 to 1, lipidic particles can be observed in the fracture faces.

Effect of lanthanide ions on the phase behavior of dipalmitoylphosphatidylcholine multilamellar liposomes.

The effect of lanthanide ions (Ln3+) and their coordination compounds of diethylenetriamine pentaacetic acid (DTPA) on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multi-lamellar liposomes has been studied by differential scanning calorimetry (DSC), Raman spectroscopy, and freeze-fracture electron microscopic techniques. The displacement of Ca2+ binding on DPPC liposomes by lanthanide ions was also studied. The results show that the binding degree of four kinds of chloride salts with DPPC liposomes is: YbCl3 > GdCl3 > LaCl3 > CaCl2. Lanthanide ions increase the phase transition temperature of DPPC liposomes and decrease the membrane fluidity. Freeze-fracture electron microscopic results show that La3+ enhances the order of DPPC membrane. The effect of coordination compounds of lanthanides with DTPA on the phase behavior of DPPC liposomes is smaller than that of their chlorides. La3+, Gd3+, and Yb3+, can displace Ca2+ binding on DPPC liposomes, but there coordination compounds of DTPA can hardly displace Ca2+. Raman spectroscopic results show that a very slight effect in lateral packing order of DPPC liposomes was observed at various concentrations of lanthanides.

Sequelae and complications related to dental extractions in patients with hematologic malignancies and the impact on medical outcome.

OBJECTIVE: The purpose of this retrospective study was to evaluate sequelae and complications after dental extractions and to analyze their impact on medical treatment in patients with myelodysplastic syndrome, acute and chronic leukemia, and multiple myeloma during a 3-year period. STUDY DESIGN: The study population included 388 patients with hematologic malignancies. All medical and dental charts were reviewed in a retrospective fashion to identify patients who received dental extractions. Preexisting dental disease and intervention (extraction) were evaluated, and parameters such as days of hospitalization and survival rate were compared with those of the remainder population who did not receive dental extractions. RESULTS: Of the 388 patients, 69 underwent dental extractions and 9 had sequelae and complications after the intervention. The resulting complication rate of 13% was reported. Although some patients did experience delay of chemotherapy or bone marrow transplant (BMT), or both, no significant difference was found in the number of days in the hospital for BMT and the survival rate for the patients with sequelae and complications (n = 9) and for the remainder population (n = 319) ( >.05). CONCLUSION: Dental extraction intervention provided in the prechemotherapy and pre-BMT time frame did not have a negative bearing on medical outcome.

Effect of hydroxyl radical on Na(+)-K(+)-ATPase activity of the brain microsomal membranes.

Sphingomyelin liposomes and brain microsomes were oxidized by exposure to hydrogen peroxide and ferrous ion. Lipid peroxidation were measured by the formation of thiobarbituric acid- reactive substances (TBAR). Hydroxyl radical was detected using the spin- trapping technique. Incubation of sphingomyelin liposomes with H2O2-Fe2+ resulted in an increase in the formation of TBAR. Na(+)-K(+)-ATPase activity was markedly inhibited and the SH group content decreased during incubation of microsomes in the presence of H2O2-Fe2+. Sodium ferulate effectively inhibited TBAR formation, protected Na(+)-K(+)-ATPase activity and prevented the oxidative modification of SH groups. Spin-trapping experiments showed that sodium ferulate effectively scavenged the hydroxyl radicals.