Estrogen receptor α variants affect age at onset of Alzheimer's disease in a multiethnic female cohort.

BACKGROUND/AIMS: Few studies of gene variants that affect estrogen activity investigate their association with age at onset of Alzheimer's disease (AD) in women of different ethnicities. We examined the influence of ESR1 polymorphisms on age at onset of AD in a multiethnic cohort of women. METHODS: Among 1,436 women participating in the Washington Heights Inwood Columbia Aging Project, association with age at AD onset was assessed for 41 single-nucleotide polymorphisms (SNPs) on the ESR1 gene using Cox proportional hazard models, adjusting for presence of an APOE ε4 allele, years of education, and body mass index. RESULTS: Six SNPs in self-identified White women were protectively associated with delayed age of AD onset in this self-identified group, including the two restriction fragment length polymorphisms PvuII (rs2234693) and XbaI (rs9340799) (HR range = 0.420-0.483). Two separate SNPs were found to affect age of AD onset in self-identified Black women. CONCLUSIONS: ESR1 polymorphisms affect age of onset of AD in women, and risk alleles vary by ethnicity. These effects are possibly due to different linkage disequilibrium patterns or differences in comorbid environmental or cultural risk factors mediating the SNP effect on risk for AD.

Aromatase variants modify risk for Alzheimer's disease in a multiethnic female cohort.

BACKGROUND/AIMS: Few studies of gene variants that affect estrogen activity investigate their association with risk for Alzheimer's disease (AD) in women of different ethnicities. We investigated the influence of CYP19 polymorphisms on risk for AD in a multiethnic cohort of women, with individual ethnicity assessed by genetic population ancestry informative markers (AIMs) as well as by self-identified ethnicity. METHODS: Among 1,686 women participating in the Washington Heights Inwood Columbia Aging Project, association with risk for AD was assessed for 41 single nucleotide polymorphisms (SNPs) on the CYP19 gene using multivariable logistic regression, adjusting for age, presence of an APOE ε4 allele, years of education, and body mass index. RESULTS: Risk for AD was associated with 6 SNPs in women of predominantly Caucasian AIMs-defined ancestry. Of these, 2 were also associated with decreased risk of AD in women of admixed/Hispanic AIMs ancestry. Two separate SNPs were found to be protective in women of predominantly African AIMs-based ancestry. CONCLUSIONS: CYP19 polymorphisms affect risk for AD in women, and risk alleles vary by AIMs-defined ancestry. These effects are possibly due to linkage disequilibrium patterns or differences in the prevalence of comorbid risk factors mediating the SNP effect on risk for AD by group.

Dissolution test for ivermectin in oral veterinary paste.

A dissolution test for oral veterinary pastes with ivermectin using the Ph. Eur. paddle apparatus was developed. Sink conditions were achieved with sodium lauryl sulphate in a concentration of 0.5% as dissolution medium. By means of HPLC fast degradation of ivermectin was observed in HCl 0.1 M solution. Rotation speed of the paddle at 75 rpm was appropriate as demonstrated in a study comparing two different products.

Development, evaluation, and application of sediment quality targets for assessing and managing contaminated sediments in Tampa Bay, Florida.

Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting relatively uncontaminated areas of the bay from contamination and reducing the amount of toxic chemicals in contaminated sediments have been identified as high-priority sediment management objectives for Tampa Bay. To address concerns related to sediment contamination in the bay, an ecosystem-based framework for assessing and managing sediment quality conditions was developed that included identification of sediment quality issues and concerns, development of ecosystem goals and objectives, selection of ecosystem health indicators, establishment of metrics and targets for key indicators, and incorporation of key indicators, metrics, and targets into watershed management plans and decision-making processes. This paper describes the process that was used to select and evaluate numerical sediment quality targets (SQTs) for assessing and managing contaminated sediments. These SQTs included measures of sediment chemistry, whole-sediment and pore-water toxicity, and benthic invertebrate community structure. In addition, the paper describes how the SQTs were used to develop site-specific concentration-response models that describe how the frequency of adverse biological effects changes with increasing concentrations of chemicals of potential concern. Finally, a key application of the SQTs for defining sediment management areas is discussed.

Dose reduction of inhaled corticosteroids under concomitant medication with montelukast in patients with asthma.

The present study aimed at comparing the effects of a dose reduction of inhaled corticosteroids on lung function, indirect measures of airway inflammation and clinical scores during treatment with a leucotriene receptor antagonist. In 50 patients (mean forced expiratory volume in one second (FEV1) 94% predicted), steroid doses (800 microg beclomethasone dipropionate) were first reduced to 50% and then to 25%, for 6 weeks each. One group received a placebo and the other group received montelukast (10 mg). The first reduction did not cause significant effects. During the second, FEV1 and peak expiratory flow decreased in both groups (p<0.001). Daytime symptoms were not altered with placebo but were reduced by montelukast (p<0.05). Night-time symptoms were slightly elevated with placebo (p<0.05) but not montelukast, as well as the use of supplemental salbutamol. Changes in provocative concentration of methacholine causing a 20% fall in FEV1 (PC20), sputum eosinophils and exhaled nitric oxide were mostly nonsignificant for both placebo and montelukast. These data demonstrate that a 75% reduction in the dose of steroid given to patients with asthma led to a deterioration in lung function not prevented by montelukast, whereas changes in clinical state seemed to favour montelukast treatment. It therefore appears that potential effects of montelukast, in the presence of low-dose steroids, could not be attributed to single indices of lung function or airway inflammation.

Acute protection against exercise-induced bronchoconstriction by formoterol, salmeterol and terbutaline.

The onset of bronchoprotection as obtained by various beta2-agonists has not been examined in a comparitive study. In this study, the onset of bronchodilation and protection against exercise-induced bronchoconstriction in asthmatics after inhalation of the long-acting beta2-agonists formoterol and salmeterol and the short-acting beta2-agonist terbutaline were measured. Twenty-five subjects with asthma and a history of exercise-induced bronchoconstriction (mean baseline forced expiratory volume in one second (FEV1): 90% predicted; mean fall in FEV1 after exercise: 31% from baseline) were enrolled in this double-blind, double-dummy, placebo-controlled, randomized, four-period crossover study. Exercise challenges were performed on 12 days at either 5, 30, or 60 min after inhalation of a single dose of formoterol (12 microg Turbuhaler), salmeterol (50 microg Diskus), terbutaline (500 microg Turbuhaler) or placebo. Exercise-induced bronchoconstriction (maximum fall in FEV1 or area under the curve) did not differ significantly between terbutaline, formorerol and salmeterol either 5, 30, or 60 min after inhalation of the study medication. In contrast, the onset of bronchodilation was slower after salmeterol compared to terbutaline and formoterol (p<0.05, each), which both showed a similar time course. At all time points between 5 and 60 min, formoterol provided significantly greater bronchodilation than salmeterol (p<0.05). These data indicate that equipotent doses of the bronchodilators salmeterol, formoterol and terbutaline were similarly effective with respect to their short-term protective potency against exercise-induced bronchoconstriction, despite the fact that the time course of bronchodilation was significantly different between the three beta2-agonists.

Studies on the effect of pH on the lipoidal route of penetration across stratum corneum.

The effect of pH on the excised skin permeability towards two model lipophilic compounds was studied in the range of pH 1.0-10.0 and 1.0-12.0, for hydrocortisone and testosterone, respectively. Suspensions of the model compounds in appropriate buffers (0.1-0.2 M) were applied to the intact skin, delipidized skin, skin pretreated with Azone or sodium lauryl sulfate solution and the percutaneous penetration was observed for 28 h. Within the studied pH range, up to pH 11.0 no change in the penetration through the skin and skin accumulation was observed for both compounds. Significant, 3-4-fold, increase of penetration of testosterone was noted only at pH 12.0, however the change was neither fast not progressing with time. None of the pretreatment procedure influenced the observed relationship between pH and skin permeability. It is concluded that the lipoidal route of penetration is not affected by solutions at pH within the range 1.0-11.0.

Bioavailability of diazepam from aqueous-organic solution, submicron emulsion and solid lipid nanoparticles after rectal administration in rabbits.

The bioavailability of diazepam in rabbits after rectal administration of three formulations: organic-aqueous Relsed rectal solution (containing ethanol, benzyl alcohol and propylene glycol), submicron emulsion and solid lipid nanoparticles (SLN), was studied. Submicron emulsion contained MCT oil (20% w/w), egg lecithin and poloxamer; SLN were prepared with cetyl palmitate 10% w/v and non-ionic emulsifying agent, Plantacare. All formulations contained 4 mg/ml of diazepam and the dose administrated to rabbits was 2 mg/kg. In both submicron preparations nearly the same mean size of the dispersed particles (201-206 nm) and the fraction of the free drug in aqueous phase (0.9-1.5%) was determined. Besides very moderate prolongation of drug release, the submicron emulsion as a vehicle did not alter pharmacokinetics of diazepam when compared with the solution: the mean C(max) was 48.9+/-24.0 and 49.5+/-17.0 ng/ml, and area under the curve was 134.0+/-42.3 and 186.8+/-59.8 ng h/ml, for solution and emulsion, respectively. The low relative bioavailability, 47% compared to the solution, was observed after administration of SLN. Transmission electron microscopy pictures revealed that some of diazepam is present on the surface of the SLN and this fraction was immediately absorbed, while the diffusion of the drug in the solid core was not efficient enough to allow a complete release. It may be concluded that submicron emulsion may be a good choice of an ethanol-free drug formulation, but lipid matrix, which is solid at body temperature, is not advantageous system for diazepam rectal delivery, even if delivered as a submicron dispersion.

Evaluation of paracetamol suppositories by a pharmacopoeial dissolution test--comments on methodology.

Ph.Eur. and BP have introduced a dissolution apparatus for suppositories. Suitability of the apparatus for quality control of paracetamol suppositories was evaluated and the effect of experimental conditions on dissolution profiles was studied. Paracetamol suppositories containing 80-500 mg of the drug, on fatty base, were obtained from four manufacturers (A, B, C, D). The diffusion cell was modified by incorporation of an in-built thermoprobe and large difference (up to 1.7 degrees C) between temperature in the water-bath and in the dissolution chamber was observed. This effect was avoided by increasing the length of tubing immersed in the thermostat at the inlet of the cell. The most reproducible results were observed for A and C suppositories, however from suppository C the total dose of paracetamol was released after 3.5-4.5 h while the release from suppository A was slow with only 40-87% of the total dose liberated during 6 h. Suppositories B did not melt at 37 degrees C and less than 5% of the drug was released. Fast release was observed after melting when the temperature was elevated to 39.5 degrees C. The results demonstrate clearly that essentially complete melting of a suppository in the dissolution chamber is required for an appropriate dissolution of paracetamol in vitro. Disintegration time, softening time, drop point and particle size of the suspended drug were measured and the relevance of these parameters for dissolution behaviour of the preparations was discussed.

In vitro studies on penetration of terpenes from matrix-type transdermal systems through human skin.

Polyurethane matrices containing up to 39% of the terpenes eucalyptol, L-limonene, D-limonene, dipentene or terpinolene were produced. Release of the terpenes directly to the acceptor fluid, as well as through isolated human epidermis and dermis, was studied. In the presence of dermis the penetration profiles were very similar to the release profiles, indicating that dermis does not present a barrier for penetration of terpenes. For all terpenes the penetration was slower in the presence of epidermis (K(p) was in the range 0.21-1.8x10(-3) cm/h). Release and penetration through the epidermis and dermis were fastest for dipenetene (mixture of D-limonene and L-limonene), being at least 3-4 times faster than for D-limonene and L-limonene. Large amounts of terpenes found in epidermis (approximately 1.5 mg/cm(2)) indicate that affinity of these compounds to the stratum corneum is very high.

Ab initio calculation of inner-sphere reorganization energies of arenediazonium ion couples.

The geometries of a series of substituted arenediazonium cations (p-NO2, p-CN, p-Cl, p-F, p-H, m-CH3, p-CH3, p-OH, p-OCH3, p-NH2) and the corresponding diazenyl radicals were optimized at the HF/6-31G, MP2/6-31G, B3LYP/6-31G, B3LYP/TZP, B3PW91/TZP, and CASSCF/6-31G levels of theory. Inner-sphere reorganization energies for the single electron-transfer reaction between the species were computed from the optimized geometries according to the NCG method and compared to experimental values determined by Doyle et al. All levels of theory predicted a CNN bond angle of 180 degrees in the cation. A bent neutral diazenyl radical was predicted at all levels of theory excepting B3LYP/TZP and B3PW91/TZP for the p-Cl-substituted compound. Inner-sphere reorganization energies determined at the HF, MP2, and CASSCF levels of theory correlated poorly with both experimental results and calculated geometries. Density functional methods correlated best with the experimental values, with B3LYP/6-31G yielding the most promising results, although the ROHF/6-31G survey also showed some promise. B3LYP/6-31G calculations correctly predicted the order of the inner-sphere reorganization energies for the series, excluding the halogen-substituted compounds, with values ranging from 42.8 kcal x mol(-1) for the p-NO2-substituted species to 55.1 kcal x mol(-1) for NH2. The magnitudes of these energies were lower than the experimental by a factor of 2. For the specific cases examined, the closed-shell cation geometries showed the expected geometry about the CNN bond, with variations in the CN and NN bond lengths correlating with the electron-donating/withdrawing capacity of the substituent. As predicted by Doyle et al., a large geometry change was observed upon reduction. The neutral diazenyl radicals showed a nominal CNN bond angle of 120 degrees and variations in the CN and NN bond lengths also correlated with the electron-donating/withdrawing capacity of the substituent. Changes in theta(CNN) and r(CN) both correlated well with calculated lambda(inner). The key parameters influencing inner-sphere reorganization energy were the CN and NN bond lengths and the CNN bond angle. This influence is explained qualitatively via resonance models produced from NRT analysis and is related to the amount of CN double bond character. Based on these observations, B3LYP/6-31G calculations are clearly the most amenable for calculating inner-sphere reorganization energies for the single electron-transfer reaction between cation/neutral arenediazonium ion couples.

Diazepam submicron emulsions containing soya-bean oil and intended for oral or rectal delivery.

Physically stable diazepam submicron emulsions were prepared using soya-bean oil. Diazepam concentration 4 mg/ml, suitable for rectal or oral delivery, was achieved in 20% emulsions. Mixture of egg lecithin (1.2%) and poloxamer (2.0%) has been chosen as the most suitable emulsifying agent. Composition of the emulsion may be supplemented with alpha-tocopherol and parabens. However, the system was not stable when either phenylethanol or chlorhexidine gluconate was added. Taste masking agents commonly used as food additives decreased stability of the preparation and were not efficient in elimination of a bitter taste of the drug-loaded emulsions.

In vivo evaluation of submicron emulsions with pilocarpine: the effect of pH and chemical form of the drug.

Submicron emulsions containing 2.0% w/v pilocarpine as pilocarpine HCl, soybean oil (10% w/v) and egg lecithin (1.2% w/v) were formulated. Emulsions at pH 5.0, 6.5 and 8.5 were applied to the rabbit's eye, and the reduction in pupil diameter was measured for 6 h. The miotic effect was compared with that obtained with aqueous solutions at the same pH. A prolonged miotic effect was observed when the submicron emulsion was used as a vehicle. After application of emulsions at pH 5.0, 6.5 or 8.5, the time when 20% reduction of pupil diameter was still observed was 3.9 +/- 1.1 h, 4.3 +/- 1.3 h and 5.3 +/- 0.8 h, respectively, while, after application of a solution, this parameter was shorter by 30-40%. AUC(0-6h) values were larger after application of the submicron emulsions in comparison to aqueous solutions; however, statistically significant differences were only observed for emulsions at pH 6.5. Although the bioavailability of the drug is pH dependent, emulsions at higher pH cannot be considered for clinical use because of pilocarpine degradation which occurs with a similar rate as in aqueous solutions. Introduction of pilocarpine into the oily phase in the form of pilocarpine base or its oleate did not improve either the physicochemical or the pharmacological properties of the formulations. Irrespective of the pH and chemical form of pilocarpine used for emulsion preparation, practically all drug was found in the aqueous phase of the emulsion; thus, partitioning to the oily phase was negligible.

Submicron emulsions as drug carriers. Studies on destabilization potential of various drugs.

Few drugs have been successfully formulated as submicron emulsions. The physicochemical stability of submicron emulsions on admixture of drugs is the main factor limiting a wider use of this type of vehicle for parenteral or other routes of administration. In a short-term stability studies we have investigated 35 drugs with regard to their compatibility with 20 or 5% parenteral fat emulsions. The study has shown that interaction of drugs with submicron emulsions is complex in nature. Taking into consideration the physicochemical properties of a drug e.g. lipophilicity or ionization, it is difficult to predict changes in the physical stability of the system. If destabilization occurs it is maximal at saturated concentrations and the presence of even significant amounts of the solid phase formed by undissolved drug does not influence the short-term stability of the system. Due to the increased ratio of emulgator to oil, emulsions containing 5% of oily phase are less susceptible to destabilization than 20% emulsions.

Familial Alzheimer's disease presenilin-1 mutants potentiate cell cycle arrest.

We previously reported that overexpression of presenilin 1 and 2 (PS1 and PS2) in HeLa cells leads to cell cycle arrest, and that the PS2(N141I) FAD mutant potentiates cell cycle arrest compared to wild-type PS2. Using similar BrdU incorporation studies we now report that three different PS1 FAD mutants also increase cell cycle arrest compared to wild-type PS1 when overexpressed in either HeLa cells or an ATM deficient cell line. We detected reproducible differences in the degrees to which these FAD mutants induced arrest. PS1(P117L) reduced BrdU incorporation the most (13 to 14%) followed by PS1(P267S) (7.5 to 9%), with the PS1(E280A) mutant inhibiting BrdU incorporation the least (6 to 7%), compared to wild-type PS1. The degree to which the different mutants inhibited cell cycle progression correlates somewhat with the age of AD onset induced by the mutations in carriers. Immunoblot analysis of protein extracts from presenilin-overexpressing cells indicates that the cell cycle-regulated cytoplasmic pool of beta-catenin is dramatically reduced, whereas the insoluble beta-catenin pool remains essentially unaffected. We discuss the implications of these findings in relationship to cell cycle arrest, apoptosis and AD.

Increased partitioning of pilocarpine to the oily phase of submicron emulsion does not result in improved ocular bioavailability.

Submicron emulsions containing pilocarpine as ion-pair with mono-dodecylphosphoric acid were prepared. Physical stability of these preparations was confirmed during 4 months of storage at 4 degrees C. Approximately 50% of the drug was found in the aqueous phase of emulsion separated using an ultrafiltration technique, while the rest was present in the oily phase and interphase. The miotic effect observed in rabbits after application of the ion-pair in aqueous solution or in submicron emulsion was the same; indicating that the drug distribution into the oily phase of the colloidal vehicle does not improve ocular bioavailability.

Investigation of diazepam lipospheres based on Witepsol and lecithin intended for oral or rectal delivery.

Diazepam was incorporated in lipospheres prepared by high pressure homogenization of melted Witepsol (10%) dispersed in aqueous lecithin (2.4%). Diazepam content was 0.4% and more than 98% of the dose was found to be encapsulated in the lipospheres. Although the initial mean particle size was 0.3 micron, the liposhperes agglomerated during storage and this phenomenon was not eliminated by increasing lecithin concentration to 4% or incorporation of oleic acid (0.1%) and co-surfactants, polysorbate 80 (0.5%) or poloxamer (up to 6%). The formulation was not able to mask effectively bitter taste of diazepam, even when lipids of higher melting temperature, namely glyceryl tripalmitate or stearic acid, were introduced.

Effect of penetration enhancers on isosorbide dinitrate penetration through rat skin from a transdermal therapeutic system.

Percutaneous absorption of isosorbide dinitrate (ISDN) from a transdermal therapeutic system (TTS) with or without penetration enhancers was studied. The concentration of ISDN and its metabolites, isosorbide-5-mononitrate (IS-5-MN) and isosorbide-2-mononitrate (IS-2-MN), was determined in rat plasma during a 48 h application of TTS. The increased skin-penetration enhancing effect of oleic acid and propylene glycol in comparison to polyethylene glycol 400 and isopropyl myristate on percutaneous permeation of ISDN was shown. It was expressed by higher values of C(max) and AUC. After the application of TTS, a lower ISDN and molar ratio of its metabolites was observed than after oral administration.

[Percutaneous absorption of heparin: a critical review of experimental results]. / Wchlanianie heparyny przez skóre--krytyczna ocena wyników badan.

Percutaneous penetration of heparin is limited by its large molecular weight, negative charge and hydrophilicity. Although some authors did not find any significant anticoagulant effect of transdermally delivered heparin but several other papers indicate that heparin penetrates the skin barrier. The actual article provides a critical review of the in vitro and in vivo studies on percutaneous absorption of heparin and heparinoids. It is concluded that there is no sufficient evidence that heparin is able to penetrate intact skin. However under clinical conditions the integrity of the skin barrier may be changed what results in promotion of heparin penetration and justifies usage of topical drug formulations like ointments and gels.