Chemical characterization of chestnut cultivars from three consecutive years: Chemometrics and contribution for authentication

Four Castanea sativa Miller cultivars (Aveleira, Boaventura, Judia and Longal) belonging to the Protected Designation of Origin “Castanha da Terra Fria”, from the Northeast of Portugal, were selected in 2006, 2007 and 2008. Their nutritional, fatty acids, triacylglycerols and tocopherols profiles were evaluated. Water was the major component, followed by carbohydrates, protein and fat, with energetic values lower than 190 kcal/100 g of fresh fruit. Oleic, linoleic and palmitic were the major fatty acids, 1-oleoyl-2-linoleoyl-3-linoleoyl-sn-glycerol, 1-linoleoyl-2-linoleoyl-3-palmitoyl-sn-glycerol, 1-oleoyl-2-linoleoyl-3-oleoyl-sn-glycerol and 1-linoleoyl-2-oleoyl-3-palmitoyl-sn-glycerol were the prevalent triacylglycerols and γ-tocopherol was the most abundant tocopherol. In each parameter, differences between cultivars, harvest year and the possible cultivar × year interaction were screened through a two-way analysis of variance. Differences among cultivars have been attenuated by the variability among years, leading, in general, to a significant interaction effect, which resulted in a relative homogeneity regarding chemical parameters, showing that nutritional and chemical composition was influenced by seasonal variability. A stepwise linear discriminant model, based on 10 (α-tocopherol, γ-tocotrienol, LLL, OLLn, δ-tocopherol, γ-tocopherol, δ-tocotrienol, PLLn, protein and OOO) of the 38 initial evaluated variables was also established. The model allowed the complete discrimination of cultivars with overall sensibilities and specificities of 100%, for both original grouped data and leave-one-out cross-validation procedures. Furthermore, similar results were also obtained using only tocopherols data, showing their usefulness as a discriminant factor for chestnut cultivars.     

Nafoxidine-responsive uterine protein: further characterization and distinction from the "estrogen-induced" protein (IP)

In a previous paper, we reported that nafoxidine (UA) stimulated the synthesis of a uterine protein showing the same electrophoretic mobility as the "estrogen-induced protein" (E2-IP) first described by Notides and Gorski. In the present work, we analyzed the IP-containing electrophoretic zone by SDS polyacrylamide-gel electrophoresis, and found that estradiol-17 beta (E2) and nafoxidine stimulated the synthesis of different proteins. As expected, estradiol-17 beta stimulated the synthesis of the E2-IP of 46 000 Mr. On the other hand, UA stimulated the synthesis of 27 000 and 30 000 Mr proteins (UA-IP). These UA-IP were not precipitated by an antiserum raised against E2-IP. Therefore, UA-IP appear to be independent entities and not degradation or precursor products of E2-IP. Both UA-IP are constitutively present in the uterus and even in higher relative amounts in rat brain. The present finding, that an "anti-estrogen", such as nafoxidine, stimulates the synthesis of different proteins than estrogen, provides a new approach to the study of the molecular mechanism of estrogen action.     

Differentiation between steroid hormone receptors CBG and shbg in human target organ extracts by a single-step assay

The steroid complexes of (plasma) corticosteroid-binding globulin can be distinguished from intracellular steroid-receptor complexes by agar electrophoresis at low temperature in neuraminidase-treated tissue extracts. With this method, the presence of progesterone receptor has been demonstrated in heavily plasma-protein-contaminated human uterus “cytosol”, but not in human mammary carcinoma extracts. SHBG and “basic” receptors for estradiol and dihydrotestosterone in human uterus cytosol could also be assayed simultaneously.     

怀菊花期次生代谢物含量及同功酶活性动态变化研究

目的：研究怀菊花期次生代谢产物的合成代谢规律及同工酶活性的动态变化。方法：测定怀菊花期总黄酮、绿原酸、花青苷的含量，以及苯丙氨酸解氨酶（PAL）、多酚氧化酶（PPO）、过氧化物酶（POD）的活性。结果与结论：怀菊花期各指标均呈先升高后下降的变化趋势，但高峰值出现的时间不同，总黄酮和绿原酸的高峰值出现在花开70％时，花青苷含量于花开50％时达到最高，PPO活性则在花开30％时最高，且2个栽培类型的变化趋势一致；PAL和POD的变化趋势因栽培类型的变化而有一定的差异，怀大白菊中PAL和POD活性在花开70％和30％时最高，而怀小白菊中则出现在花开50％。     

New payment systems: a brilliant opportunity for cytology

An explanation is offered of new payment systems, and an optimistic, practical approach is suggested for dealing with them.     

All-Atom Molecular Dynamics Simulations of Poly(2,6-dimethyl-1,4-phenylene) Oxide: Validation of OPLS-AA Force Field for Conformational Behaviour in Vacuum and in Carbon Tetrachloride

OPLS force field has been successfully validated for poly(2,6-dimethyl-1,4-phenylene) oxide (PPO) in comparison with quantum chemical results and available experimental data. The formation of stable polymer solvent complexes, where solvent molecules are hosted in closed loops, has been detected in molecular dynamics (MD) simulations of OPLS all-atom (OPLS-AA) models of diluted solutions of PPO in CCl₄. Estimations of free energy of solvation indicate an entropic stabilization of the polymer solvent complexes. A very high similarity of these structures with the intra-helical channels observed in the structure of PPO co-crystals suggests their possible role in the nucleation process inducing the crystallization of PPO from organic solvents.     

Amino-functionalized poloxamer 407 with both mucoadhesive and thermosensitive properties: preparation,characterization and application in a vaginal drug delivery system

Lack of mucoadhesive properties is the major drawback to poloxamer 407 (F127)-based in situ hydrogels for mucosal administration. The objective of the present study was to construct a novel mucoadhesive and thermosensitive in situ hydrogel drug delivery system based on an amino-functionalized poloxamer for vaginal administration. First, amino-functionalized poloxamer 407 (F127-NH₂) was synthesized and characterized with respect to its micellization behavior and interaction with mucin. Then using acetate gossypol (AG) as model drug, AG-loaded F127-NH₂-based in situ hydrogels (NFGs) were evaluated with respect to rheology, drug release, ex vivo vaginal mucosal adhesion, in vivo intravaginal retention and local irritation after vaginal administration to healthy female mice. The results show that F127-NH₂ is capable of forming a thermosensitive in situ hydrogel with sustained drug release properties. An interaction between positively charged F127-NH₂ and negatively charged mucin was revealed by changes in the particle size and zeta potential of mucin particles as well as an increase in the complex modulus of NFG caused by mucin. Ex vivo and in vivo fluorescence imaging and quantitative analysis of the amount of AG remaining in mouse vaginal lavage all demonstrated greater intravaginal retention of NFG than that of an unmodified F127-based in situ hydrogel. In conclusion, amino group functionalization confers valuable mucoadhesive properties on poloxamer 407.     

Choline uptake, acetylcholine synthesis and release by Limulus abdominal ganglia

Isolated ganglia from the ventral nerve cord of the horseshoe crab, Limulus polyphemus, were incubated in [³H]choline and subsequently analyzed for choline uptake, conversion of choline to acetylcholine and the release of the newly synthesized acetylcholine. The ganglia readily accumulated radioactivity when incubated in Chao's solution containing 2 μM [³H]choline. The rate of uptake was 0.08 pmols/min/mg tissue and 26% of the [³H]choline taken up during a 1 h period was converted to [³H]acetylcholine. A 15 min exposure of ganglia to 90 mM K⁺ prior to incubation in [³H]choline caused an 89% increase in choline uptake and a 150% increase in its conversion to [³H]acetylcholine. The presence of unlabeled acetylcholine in the uptake medium inhibited both uptake and conversion of [³H]choline.There was a 5-fold increase in the efflux of radioactivity when ganglia incubated in 2 μM [³H]choline were superperfused with 90 mM K⁺. The increased efflux of radioactivity was Ca²⁺-dependent and was inhibited by Mg²⁺ (44%) and by Co²⁺ (72%). Similarly, addition of veratridine caused a Ca²⁺ and Na⁺-dependent release of radioactivity from prelabeled ganglia. Analysis of the superperfusate revealed that virtually all of the released radioactivity was [³H]acetylcholine.The abdominal ganglia of Limulus take up choline at micromolar concentrations, convert substantial amounts of it to acetylcholine and possess a depolarization-triggered, Ca²⁺-requiring mechanism for the specific release of acetylcholine. These results give further support to the view that the abdominal ganglia of Limulus contain a population of cholinergic terminals.     

Radioimmunoassay of thyroxine-binding globulin in human plasma

A highly specific and precise radioimmunoassay for thyroxine-binding globulin (TBG) has been developed. Crossreactivity with albumin and prealbumin was excluded. The normal range in young adults was 0.97 mg/100 ml. In childhood TBG was elevated (1.34 mg/100 ml) and also in old age (1.28 mg/100 ml). In normals and in childhood there was a good correlation of TBG with thyroxine (T₄). T₄ did not correlate with TBG with regard to age. Triiodothyronine (T₃) did not correlate with TBG in any group.T₄and T₃ exhibited a progressive decrease with age. No correlation between age and TBG was found. In mild thyrotoxicosis (T₃ : 4.5 ng/ml, with normal T₄ and negative TRH-test) TBG was slightly increased (1.20 mg/100 ml), whereas in more severe hyperthyroidism (T₃ : 6.4 ng/ml, T₄ : 16.3 Mg/100 ml) TBG concentration was not significantly different from normals. In hypothyroidism TBG was elevated (1.26 mg/100 ml).The conclusion from these data is that TBG does not follow the progressive decrease of T₄ and T₃ with age. Thus, age-dependent euthyroid ranges for thyroid hormone concentration, including TBG concentration, must be established for better clinical discrimination of thyroid function. Possible dependence of TBG on the nature of thyroid hormone concentration must be considered in the production and peripheral kinetics of thyroid hormones.     

Modulation of Intestinal Transport and Absorption of Topotecan,a BCRP Substrate,by Various Pharmaceutical Excipients and Their Inhibitory Mechanisms of BCRP Transporter

Breast cancer resistance protein transporter (ABCG2/BCRP) is highly expressed on the intestinal epithelial membrane and has a significant impact on the oral absorption of topotecan. In this study, we examined 6 pharmaceutical excipients including BL-9EX, Brij97, Cremophor EL, Labrasol, Pluronic F68, and Tween 20 for their BCRP inhibitory effects. A bidirectional transport study using Caco-2 cells demonstrated that Tween 20 and Cremophor EL significantly increased the absorptive transport of topotecan, while simultaneously decreasing secretory transport. Interestingly, Labrasol selectively increased absorptive transport, whereas Pluronic F68 selectively decreased the secretory transport, of topotecan. Further investigation using an in situ closed loop experiment showed that 0.05% (w/v) Tween 20 and Cremophor EL significantly increased the intestinal absorption of topotecan in rats. An LDH assay demonstrated that 0.05% (w/v) Tween 20 and Cremophor EL did not cause significant damage to intestinal epithelial membranes. Furthermore, we examined the absorption-enhancing mechanisms of these excipients and found that Cremophor EL, Tween 20, and Labrasol increased the membrane fluidity of the inner lipid bilayers of the intestine. Therefore, this might be one of the most important mechanisms for inhibition of BCRP function by these excipients in the intestine.