Anti-oxidative effect of fluvastatin in hyperlipidemic type 2 diabetic patients. (33/116)

An open-label prospective cross-over trial was performed to evaluate the antioxidative effect of fluvastatin in Japanese type 2 diabetics with hyperlipidemia. The study subjects were 10 patients who were on pravastatin (10 mg/day) or simvastatin (5 mg/day). After at least 12 weeks of continuous pravastatin or simvastatin therapy, the drugs were washed out for 12 weeks and replaced with fluvastatin (30 mg/day), then the treatment was continued for another 12 weeks. Total cholesterol and LDL cholesterol were efficiently and comparably reduced by all three statin agents. There were no differences in serum parameters of oxidative stress such as malondialdehyde-modified low-density lipoprotein, thiobarbituric acid-reactive substances, and 8-iso-prostaglandin F2alpha between pravastatin/simvastatin and fluvastatin. However, fluvastatin, but not pravastatin/simvastatin, significantly reduced 3,5,7-cholestatriene in erythrocyte membrane, representing the extent of membrane cholesterol peroxidation. Our data demonstrated that fluvastatin has a unique anti-oxidative effect in patients with type 2 diabetes and hyperlipidemia, compared with other statins.  (+info)

Hepatocytes targeting of cationic liposomes modified with soybean sterylglucoside and polyethylene glycol. (34/116)

AIM: In this study, a hepatocyte-specific targeting technology was developed by modifying cationic liposomes with soybean sterylglucoside (SG) and polyethylene glycol (PEG) (C/SG/PEG-liposomes). METHODS: The liposomal transfection efficiencies in HepG(2) 2.2.15 cells were estimated with the use of fluorescein sodium (FS) as a model drug, by flow cytometry. The antisense activity of C/SG/PEG-liposomes entrapped antisense oligonucleotides (ODN) was determined as HBsAg and HBeAg in HepG(2) 2.2.15 cells by ELISA. The liposome uptake by liver and liver cells in mice was carried out after intravenous injection of (3)H-labeled liposomes. RESULTS: C/SG-liposomes entrapped FS were effectively transfected into HepG(2) 2.2.15 cells in vitro. C/SG/PEG-liposomes entrapped ODN, reduced the secretion of both HBsAg and HBeAg in HepG(2) 2.2.15 cells when compared to free ODN. After in vivo injection of (3)H-labeled C/SG/PEG-liposomes, higher radiation accumulation was observed in the hepatocytes than non-parenchymal cells of the liver. CONCLUSION: C/SG/PEG-liposomes mediated gene transfer to the liver is an effective gene-delivery method for hepatocytes-specific targeting, which appears to have a potential for gene therapy of HBV infections.  (+info)

cDNA cloning, genomic structure and expression analysis of the bovine lanosterol 14alpha-demethylase (CYP51) in gonads. (35/116)

Meiosis activating sterol (MAS), the intermediate of cholesterol biosynthesis, is an important substance to stimulate oocytes maturation in FSH-induced signal transduction pathway. Lanosterol 14alpha-demethylase (CYP51) converts lanosterol to MAS. Although MAS is firstly isolated from bovine testis, the information about bovine CYP51 gene and its expression is little. In present studies, the cDNA cloning, genomic structure, chromosomal mapping, and expression patterns of bovine CYP51 were demonstrated. The cDNA coding bovine CYP51 contains a 1509 bp open reading frame and a 1119 bp 3' untranslated region. And the bovine CYP51 gene includes 10 exons and spans about 17 kb. Screening the cattle RH5000 panel bovine CYP51 is mapped to chromosome 4 (0cR). The sequenced promoter region is TATA-less and contains several highly conserved regulatory elements, such as GC-box, cAMP-responsive elements (CRE), sterol regulatory element (SRE) which is important fragment for its transcription. No evidence of processed pseudogenes is found using long PCR and Southern blot. Northern blot analysis reveals that an approximately 2.7 kb mRNA is expressed in all the examined bovine tissues, while a 1.8 kb mRNA is found only in the mature bovine testis where the MAS is accumulated. Immunochemistry analysis shows that leydig cells express the highest level of the CYP51 protein in testis. Among different stages follicles it is localized primarily to the oocytes with the level varying slightly. Granulosa cells of primordial, primary and secondary follicles show background staining. While granulosa cells facing the antrum and cumulus granulosa cells of antral follicles show considerably heavier staining. The highest level is expressed in corpus lutea. These data indicate a stage- and cell type-specific expression of CYP51 protein in bovine oogenesis.  (+info)

Identification of sokotrasterol sulfate as a novel proangiogenic steroid. (36/116)

The potential to promote neovascularization in ischemic tissues using exogenous agents has become an exciting area of therapeutics. In an attempt to identify novel small molecules with angiogenesis promoting activity, we screened a library of natural products and identified a sulfated steroid, sokotrasterol sulfate, that induces angiogenesis in vitro and in vivo. We show that sokotrasterol sulfate promotes endothelial sprouting in vitro, new blood vessel formation on the chick chorioallantoic membrane, and accelerates angiogenesis and reperfusion in a mouse hindlimb ischemia model. We demonstrate that sulfation of the steroid is critical for promoting angiogenesis, as the desulfated steroid exhibited no endothelial sprouting activity. We thus developed a chemically synthesized sokotrasterol sulfate analog, 2beta,3alpha,6alpha-cholestanetrisulfate, that demonstrated equivalent activity in the hindlimb ischemia model and resulted in the generation of stable vessels that persisted following cessation of therapy. The function of sokotrasterol sulfate was dependent on cyclooxygenase-2 activity and vascular endothelial growth factor induction, as inhibition of either cyclooxygenase-2 or vascular endothelial growth factor blocked angiogenesis. Surface expression of alpha(v)beta(3) integrin was also necessary for function, as neutralization of alpha(v)beta(3) integrin, but not beta(1) integrin, binding abrogated endothelial sprouting and antiapoptotic activity in response to sokotrasterol sulfate. Our findings indicate that sokotrasterol sulfate and its analogs can promote angiogenesis in vitro and in vivo and could potentially be used for promoting neovascularization to relieve the sequelae of vasoocclusive diseases.  (+info)

Uptake of cholesterol by the retina occurs primarily via a low density lipoprotein receptor-mediated process. (37/116)

PURPOSE: In this study we examined the uptake of circulating lipoproteins into the retina, using a naturally fluorescent cholesterol analog for imaging and deuterated cholesterol for quantification by mass spectroscopy. The purpose of this study was to better understand cholesterol uptake, transport and homeostasis in the retina. METHODS: Human low density lipoprotein (LDL) and high density lipoprotein (HDL) were labeled with the fluorescent cholesterol analog cholesta-5,7,9(11)-trien-3beta-ol (CTL) and deuterated cholesterol (25,26,26,26,27,27,27-[2H]cholesterol, D7Ch). Rats were injected intravenously with CTL-LDL, CTL-HDL and D7Ch-LDL. Fluorescent confocal microscopy was used to image the uptake of CTL and mass spectroscopy was used to quantify D7Ch. Immunohistochemistry and fluorescent confocal microscopy were used to localize apoB (an LDL marker protein) and LDL receptor (LDLR) protein in rat and monkey retinas. RESULTS: CTL-specific fluorescence was imaged by confocal microscopy in the retinal pigment epithelium (RPE), choriocapillaris and parts of the neural retina within 2 h post-injection and was visualized in the photoreceptor outer segments by 4 h. Replacing LDL with HDL as the CTL carrier gave a less robust and more delayed labeling of retinal layers. Human apolipoprotein B (apoB) was also localized in the rat choriocapillaris and RPE by 4 h post-injection. Human apoB was detected by immunoblot analysis in the rat retina primarily as a about 70 kDa protein, suggesting proteolytic degradation. LDL-mediated uptake of cholesterol was quantified by mass spectroscopy using deuterated cholesterol in place of CTL. In addition, apoB and LDLR were localized in monkey retina by immunohistochemistry. CONCLUSIONS: The retina is capable of rapid uptake of circulating LDL via an LDLR-mediated process primarily occurring in the RPE and also possibly Muller cells. Despite the dominance of HDL over LDL in rat serum, LDL appears to be the preferred carrier for cholesterol transport to and uptake by the retina. The results also suggest that blood-borne LDL represents a significant contributor to the steady-state levels of cholesterol and possibly other lipids in the retina.  (+info)

Influence of follicular fluid meiosis-activating sterol on aneuploidy rate and precocious chromatid segregation in aged mouse oocytes. (38/116)

BACKGROUND: Follicular fluid meiosis-activating sterol (FF-MAS) protects young oocytes from precocious chromatid separation (predivision). Reduced expression of cohesion and checkpoint proteins and predivision has been hypothesized to occur in age-related aneuploidy in oocytes. METHODS: To know whether FF-MAS also protects aged oocytes from predivision and from age-related non-disjunction, we analysed chromosome constitution in mouse oocytes matured spontaneously with or without 10 microM FF-MAS and in hypoxanthine (HX)-arrested young and aged oocytes induced to resume maturation by FF-MAS. Messenger RNA for checkpoint protein MAD2 and cohesion protein SMC1beta was compared between oocytes matured with or without FF-MAS. RESULTS: Aged oocytes possessed many bivalents with single distal chiasma at meiosis I. Predivision was especially high in aged oocytes cultured sub-optimally to metaphase II in alpha-minimum essential medium (alpha-MEM). FF-MAS reduced predivision significantly (P < 0.001) but neither reduced non-disjunction nor induced aneuploidy in aged oocytes. Polyploidy was high in FF-MAS-stimulated maturation, in particular in the aged oocytes (P > 0.001). Relative levels of Smc1beta mRNA appeared increased by maturation in FF-MAS, and mitochondrial clustering was restored. CONCLUSIONS: Sister chromatids of aged oocytes appear to be highly susceptible to precocious chromatid separation, especially when maturation is under sub-optimal conditions, e.g. in the absence of cumulus and FF-MAS. This may relate to some loss of chromatid cohesion during ageing. FF-MAS protects aged oocytes from predivision during maturation, possibly by supporting Smc1beta expression, thus reducing risks of meiotic errors, but it cannot prevent age-related non-disjunction. Aged oocytes appear prone to loss of co-ordination between nuclear maturation and cytokinesis suggesting age-related relaxed cell cycle control.  (+info)

Effect of rescuing donated immature human oocytes derived after FSH/hCG stimulation following in vitro culture with or without Follicular Fluid Meiosis Activating Sterol (FF-MAS)--an embryo chromosomal and morphological analysis. (39/116)

PURPOSE: Studies in mice and humans have shown that Follicular Fluid - Meiosis Activating Sterol (FF-MAS) induces meiotic maturation of immature oocytes in vitro. A multicenter, prospectively randomised study evaluated chromosomal status of embryos from FSH/hCG primed human immature oocytes, cultured with or without FF-MAS. METHODS: Denuded immature oocytes (n=365) were randomly allocated into inert control, FF-MAS 5 microM or 20 microM. Seventy +/-2 hours after ICSI on matured oocytes, all cleaved embryos were fixed for fluorescence in situ hybridisation analysis. RESULTS: Only 15% of oocytes resulted in cleaved embryos. GV oocytes matured at significantly lower rates (14% and 7%) in the two FF-MAS groups compared to the inert control group (47%). High rates of chromosomal abnormalities were found in all groups. CONCLUSION: Immature oocytes showed poor development with high rates of embryo chromosomal abnormalities. Exposure to FF-MAS in the concentrations, duration and/or formulation used in this study did not improve the results.  (+info)

Human immature oocytes grow during culture for IVM. (40/116)

BACKGROUND: Oocyte competence for maturation and embryogenesis is associated with diameter in many mammals. We aimed to test whether this relationship exists in humans and to quantify its impact upon in vitro maturation (IVM). METHODS: We used computer-assisted image analysis daily to measure average diameter, zona thickness and other parameters in oocytes. Immature oocytes originated from unstimulated patients with polycystic ovaries, and from stimulated patients undergoing intracytoplasmic sperm injection (ICSI). Some were cultured with meiosis activating sterol (FF-MAS). Matured oocytes were inseminated using ICSI and embryo development was monitored. In vivo matured oocytes were also measured. RESULTS: Immature oocytes were smaller at collection than in vivo matured oocytes. Maturation was related to oocyte diameter and many oocytes grew in culture. FF-MAS stimulated growth in oocytes derived from ICSI patients, but only stimulated growth in PCO derived oocytes if they matured in vitro. Degenerating oocytes showed cytoplasmic shrinkage. Neither zona thickness, perivitelline space, nor the total diameter of the oocyte plus zona were informative regarding maturation capacity. CONCLUSIONS: Immature oocytes grow during maturation culture. FF-MAS promotes oocyte growth in vitro. Oocytes from different sources have different growth profiles in vitro. Measuring oocytes in clinical IVM may provide additional non-invasive information that could potentially avoid the use of growing oocytes.  (+info)