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PubMedDate not supplied

Effect of alpha-, beta- and gamma-cyclodextrins on oxygen evolution by the thylakoid membrane. influence of pH and temperature.

The present work investigates the effect of alpha-, beta- and gamma-cyclodextrins (CD), i.e., alpha-CD, beta-CD and gamma-CD, on the oxygen evolution activity, the protein content and the uv-vis spectroscopic characteristics of thylakoid membranes. To study the pH-dependence, the thylakoids were incubated with the cyclodextrins at 273 K for a period of 10 min in the pH range from 5.5 to 9.0. To study the temperature-dependence the membranes were incubated at 273 and 293 K at pH 6.5, that is, the pH which induces a maximal oxygen evolution in the thylakoid preparations. The major observations are: (i) a stimulation of oxygen evolution in thylakoids incubated with alpha- and beta-CD either in acidic or alkaline conditions, (ii) a low inhibitory effect induced by gamma-CD on oxygen evolution, (iii) a significant decrease of the stimulatory effect of alpha- and beta-CD on oxygen evolution as the incubation temperature is raised from 273 to 293 K, (iv) the apparent inability of the cyclodextrins to change the protein contents of the thylakoids, and (v) a significant CD-induced red-shift from 681 to 683 nm observed in the absorption and second derivative spectra of the thylakoid membranes treated with beta-CD. First, it was found that the temperature effect described here is in accord with the general trend of the chemical effect of various cyclodextrins, i.e., the increase of the CD efficiency with decreasing temperature. Secondly, the CD effect is related to the size of the inner cavity diameter of the cyclodextrin molecules. An important conclusion in this work is that the molecular targets of the cyclodextrins are not limited to the thylakoid lipids as was described previously [Rawyler A. and Siegenthaler PA. (1996) Biochim. Biophys. Acta 1278, 89-97], but are located as well in other molecular species exposed at the stromal side of the thylakoid membrane. In particular, the CD-induced red-shift from 681 to 683 nm in the absorption and second derivative spectra of the thylakoid membranes indicates that the cyclodextrins targets might be either the exposed heme macrocycle in cytochrome b559, or the chlorophylls and pheophytins in the pigment-proteins of the photosystems I and II.

Chloroplasts↗
PubMed2001

Treatment of Raynaud's phenomenon with intravenous prostaglandin E1alpha-cyclodextrin improves endothelial cell injury in systemic sclerosis.

OBJECTIVE: To evaluate the efficacy and safety of prostaglandin (PG) E1alpha-cyclodextrin for Raynaud's phenomenon (RP) secondary to systemic sclerosis (SSc) and its effect on variables of immune activation and endothelial injury in SSc such as tumor necrosis factor-alpha (TNF-alpha), soluble interleukin 2 receptor (sIL-2R), circulating intercellular adhesion molecule-1 (cICAM-1), von Willebrand factor (vWF), and tissue-type plasminogen activator (t-PA). METHODS: We studied 36 women with SSc, 24 of them given three 60 microg intravenous PGE1alpha-cyclodextrin infusions on 5 consecutive days at 6 week intervals during the winter. RP symptoms and healing of digital lesions were evaluated. Twenty age matched healthy women were the controls. TNF-alpha, sIL-2R, cICAM-1, vWF, and t-PA were measured after the first and last infusion of PGEE1alpha-cyclodextrin and correlated with clinical features. RESULTS: RP symptoms improved in 87% of the patients. The benefit of each 5 day cycle lasted 4 or more weeks in 75%. PGE1alpha-cyclodextrin reduced the daily frequency of RP symptoms by 20% (p < 0.05), 41% (p < 0.005), and 53% (p < 0.0005) from baseline after the 1st, 2nd, and 3rd infusions, respectively. The severity of the attacks was reduced to a limited degree. In 12 of the 14 patients with digital lesions, these healed completely. Ten patients had mild side effects during treatment (headache, increased intestinal motility, flushing). TNF-alpha, sIL-2R, cICAM-1, vWF, and t-PA plasma concentrations were significantly higher in patients with SSc than controls (p < 0.05, p < 0.001). TNF-alpha, sIL-2R, and cICAM-1 were higher in diffuse SSc and patients with lung involvement. The plasma levels of cICAM-1 and t-PA were significantly reduced after the 1st infusion of PGE1alpha-cyclodextrin (both p < 0.005) and further reduced after the last (p < 0.0005 and p < 0.005). CONCLUSION: PGE1alpha-cyclodextrin reduces RP symptoms and plasma levels of the markers of endothelial injury in SSc, suggesting that an improvement of endothelial dysfunction contributes to its prolonged therapeutic effect.

Adult↗
PubMed1992

Bile acid and sterol solubilization in 2-hydroxypropyl-beta-cyclodextrin.

The use of 2-hydroxypropyl-beta-cyclodextrin has made it possible to prepare stable aqueous solutions of cholesterol, 26-hydroxycholesterol, 7 alpha-hydroxycholesterol, and monohydroxy bile acids such as lithocholic and 3 beta-hydroxy-5-cholenoic acids. These solutions are suitable for cell culture studies and for parenteral administration to animals.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1989

[Preventive effect of OP-41483-alpha-CD on cyclosporine A-induced renal tubular and arterial damages].

The aim of this study is to test whether a stable analogue prostaglandin I2 (OP-41483-alpha-CD) (OP) is effective to prevent Cyclosporine A (CsA)-induced nephrotoxicity. Male Lewis rats were administrated with CsA (50 or 100 mg/kg/day, per os) and treated with OP (25 micrograms/kg/day, subcutaneously). For the quantitativeness of qualitative changes, percent area of tubular vacuolization and the grade of renal arteriolar changes were evaluated at light microscopic level, then further examined under electron microscopy. CsA trough levels in the whole blood were also analyzed with HPLC and prostaglandin I2 was assayed by radioimmunoassay of its stable degeneration product 6-keto-PGF1-alpha. As a result, 1) ultrastructurally, perinuclear vacuoles in arteriolar media consisted of cellular intervaginated cytoplasmic processes of neighboring cells, suggesting spastic vasoconstriction induced by CsA, 2) survival rate of OP-treated rats were significantly high compared to that of rats with CsA alone, 3) pathologically, tubular and arterial damages were reduced in OP-treated models, 4) pharmacokinetic studies revealed that CsA trough levels were not different from those of CsA-received alone and OP-treated models, and 5) mean blood 6-keto-PGF1-alpha excretion in rats given CsA was higher than in normal rats.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

The effect on the cornea of alpha cyclodextrin vehicle for cyclosporin eye drops.

We tested four different combinations of alpha-CD and CYA: 0.075% and 80 mg/mL alpha-CD, 0.025% CYA and 40 mg/mL alpha-CD, 0.009% CYA and 20 mg/mL alpha-CD, and 0.003% CYA and 10 mg/mL alpha-CD. We found that 0.025% CYA (alpha-CD[40 mg/mL]) resulted in the least corneal toxicity and penetrated in the cornea 5 to 10 times more than did lipophilic vehicle with CYA.

Administration, Topical↗
PubMed1994

[The beneficial effects of PGI2 analogue (OP-41483-alpha-CD) on hepatic dysfunction after warm ischemic damage].

The purpose of the experimental study was to investigate the beneficial effects of aPGI2 analogue (OP-41483-alpha-CD; aPGI2) on hepatic dysfunction after warm ischemia and reperfusion. Hepatic warm ischemia was produced by temporary clamping of the portal vein and hepatic artery. Experimental groups were divided into three groups: Group I; 60-minutes ischemia, Group II; 90-minutes ischemia, Group III; 90-minutes ischemia with intravenous aPGI2 (0.25 microgram/kg/min) infusion. The results were as follows: 1; In groups I and III, hepatic tissue flow showed a marked increase after reperfusion when compared to Group II. 2; Arterial ketone body ratio in Groups I and III recovered significantly faster than those of Group II. 3; The tissue total adenine-nucleotide levels in Groups I and III were significantly higher than those of Group II. 4; In the comparison of the radical intensity which was measured by ESR spectroscopy, the free radical of the hepatic venous blood was markedly generalized after reperfusion in Group II. However, production of free radical has significantly suppressed in Group III when compared to Group II. These results suggest that aPGI2-treatment might improved the ischemic damaged liver and might improve the prognosis of the transplanted patient.

Alanine Transaminase↗
PubMed1993

Effects of OP-41483.alpha-CD, a stable prostacyclin analog, on cultured endothelial cell dysfunction caused by 15(S)-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE) in vitro.

We studied the effect of OP-41483.alpha-CD, a stable prostacyclin analog, on, 15-HPETE induced bovine endothelial cell dysfunction, which was assessed by measuring a number of endothelial cells attached to plastic plates. 15-HPETE decreased the number of attached endothelial cells in a concentration- and time-dependent manner. OP-41483.alpha-CD and PGI2 significantly inhibited 15-HPETE induced dysfunction of the cells at a concentration of more than 10(-9)M. Besides, DDA (10(-6) - 10(-4)M) an adenylate cyclase inhibitor, diminished the inhibitory effect of OP-41483.alpha-CD on 15-HPETE induced cell dysfunction in a concentration-dependent manner. Furthermore, OP-41483.alpha-CD increased cAMP levels in the endothelial cells in the range of 10(-10) to 10(-8)M in a dose-dependent manner. These data suggest that OP-41483.alpha-CD could exert an inhibitory action on 15-HPETE induced endothelial cell dysfunction via partly increasing its effect on the intracellular cAMP level.

Alprostadil↗
PubMed1993

Cholesterol and 27-hydroxycholesterol 7 alpha-hydroxylation: evidence for two different enzymes.

The use of 2-hydroxypropyl-beta-cyclodextrin as a vehicle for solubilizing cholesterol and 27-hydroxycholesterol has led to a study of their rates of 7 alpha-hydroxylation in microsomal preparations from hamster liver and HepG2 cells. Addition of the vehicle alone to the cholesterol 7 alpha-hydroxylase assay always caused a several-fold increase in activity. Preloading the vehicle with cholesterol further augmented the rate of 7 alpha-hydroxycholesterol formation. Preloading the vehicle with 27-hydroxycholesterol or 27-hydroxycholestanol (molar ratio 1/1.2) minimally decreased cholesterol 7 alpha-hydroxylase activity (-12%), compared with preloading with cholestanol (-50%), a known competitive inhibitor of the enzyme. Microsomes from hamster liver yielded rates of 7 alpha,27-dihydroxcholesterol formation of 1.5 to 3.0 nmol/min per mg protein, compared with 0.3 nmol/min per mg protein for 7 alpha-hydroxycholesterol. Although cholesterol and cholestanol had minimal effects on the rate of 7 alpha-hydroxylation of 27-hydroxycholesterol, addition of an approximately equimolar amount of 27-hydroxycholestanol inhibited the rate of formation by 65%. Attempts to separate and identify the two C-27 sterol 7 alpha-hydroxylases chromatographically led to the finding that Emulgen 913 selectively inactivates 7 alpha-hydroxylation of 27-hydroxycholesterol. These results indicate that the metabolic pathway for bile acid synthesis from 27-hydroxycholesterol is not governed by cholesterol 7 alpha-hydroxylase.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1993

[Intracavernous injection of lipo prostaglandin E1 for the diagnosis of impotence: a comparative study with prostaglandin E1-CD].

Intracavernous injection of 20 micrograms prostaglandin E1-CD (PGE1-CD, 8 cases), 5 micrograms lipo prostaglandin E1 (Lipo PG-E1, 8 cases) or 10 micrograms Lipo PGE1 (9 cases) was performed in patients with functional impotence in order to comparatively analyze the diagnostic efficacy of these drugs. Full erection was observed in all patients who received intracavernous injection of 20 micrograms PGE1-CD or 10 micrograms Lipo PGE1. However, full erection was observed in 4 out of 8 patients administered 5 micrograms Lipo PGE1. RigiScan was used on all patients, and latency until erection (achievement of maximum rigidity of the base) after injection, maximum rigidity of the penile tip and base and circumferential expansion rate of the penile tip and base were measured. With regard to these RigiScan data and duration of erection, there were no significant differences among the 3 groups. There were no severe side effects in any of the patients. These findings indicate that 10 micrograms Lipo PGE1 and 20 micrograms PGE1-CD have similar effects and that Lipo PGE1 may be an effective drug for the diagnosis and treatment of impotence.

Adult↗