Development and Characterization of Enteric-Coated Immediate-Release Pellets of Aceclofenac by Extrusion/Spheronization Technique Using κ-Carrageenan as a Pelletizing Agent

In the present study, an attempt was made to prepare immediate-release enteric-coated pellets of aceclofenac, a poorly soluble nonsteroidal anti-inflammatory drug that has a gastrointestinal intolerance as its serious side effect. Formulation of enteric-coated pellets with improved solubility of aceclofenac could address both of these problems. To achieve these goals, pellets were prepared by extrusion–spheronization method using pelletizing agents that can contribute to the faster disintegration and thereby improve the solubility of the drug. Different disintegrants like β-cyclodextrin, kollidon CL, Ac-Di-Sol, and sodium starch glycolate were tried in order to further improve disintegration time. The pellets were characterized for drug content, particle size distribution, flow properties, infrared spectroscopy, surface morphology, disintegration rate, and dissolution profile. The formulations, which showed best disintegration and dissolution profiles, were coated with Eudragit L100-55, an enteric-coated polymer which does not dissolve at gastric pH but dissolves at intestinal pH, releasing the drug immediately in the dissolution medium. The optimized enteric-coated formulation containing 20% κ-carrageenan, lactose, and sodium starch glycolate as a disintegrant did inhibit the release of the drug for 2 h in 0.1 N HCl, whereas 87% of the drug was released within 45 min. The improvement was substantial when it was compared with solubility of pure drug under the same conditions. Thus, dissolution profiles suggested that combination of κ-carrageenan and sodium starch glycolate resulted into fast-disintegrating, immediate-release pellets, overcoming the bioavailability problem of the poorly soluble drug, aceclofenac, and enteric coating of these pellets avoids the exposure of aceclofenac to ulcer-prone areas of the gastrointestinal tract.     

Pattern of nucleotide substitution and divergence of prophenoloxidase in decapods

Despite the unprecedented development in identification and characterization of prophenoloxidase (proPO) in commercially important decapods, little is known about the evolutionary relationship, rate of amino acid replacement and differential selection pressures operating on proPO of different species of decapods. Here we report the evolutionary relationship among these nine decapod species based on proPO gene and types of selective pressures operating on proPO codon sites. Our analyses revealed that all the nine decapod species shared a common ancestor. The mean percentage sequence divergence at proPO gene was 34.4+/-0.6%. Pairwise estimates of nonsynonymous to synonymous ratio (omega) for Homarus americanus-H. gammarus is greater than one, therefore indicating adaptive evolution (functional diversification) of proPO in these two species. In contrast, strong purifying selection (omega<1) was observed in all other species pairs. However, phylogenetically closely related decapods revealed relatively higher omega value (omega=0.15+/-0.3) than the distantly related species pairs (omega=0.0075+/-0.005). These discrepancies could be due to higher fixation probability of beneficial mutation in closely related species. Maximum likelihood-based codon substitution analyses revealed a strong purifying selection operating on most of the codon sites, therefore suggesting proPO is functionally constrained (purifying selection). Codon substitution analyses have also revealed the evidence of strong purifying selection in haemocyanin subunits of decapods.     

Gene expression variation in Down's syndrome mice allows prioritization of candidate genes

Background  

Down's syndrome (DS), or trisomy 21, is a complex developmental disorder that exhibits many clinical signs that vary in occurrence and severity among patients. The molecular mechanisms responsible for DS have thus far remained elusive. We argue here that normal variation in gene expression in the population contributes to the heterogeneous clinical picture of DS, and we estimated the amplitude of this variation in 50 mouse orthologs of chromosome 21 genes in brain regions of Ts65Dn (a mouse model of DS). We analyzed the RNAs of eight Ts65Dn and eight euploid mice by real-time polymerase chain reaction.     

Stomach-specific drug delivery of 5-fluorouracil using floating alginate beads

A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time, target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing 5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%. Results indicate that FDF performed significantly better than the simple tablet dosage form. Published: June 22, 2007     

Nutritional and antinutritional attributes of faba bean (Vicia faba L.) germplasms growing in Bihar,India

Eleven germplasms of faba bean seeds from four agroclimatic regions of Bihar, India, have been investigated to estimate their nutritional (soluble protein, free amino acids, starch, reducing and non reducing sugar, total soluble sugar) and antinutritional (total extractable phenol and condensed tannin/proanthocyanidin) parameters. These parameters were found in varying concentration in all genotypes studied. The highest concentration of total extractable phenol and proanthocyanidin (condensed tannin) (2.56 and 1.59 % leucocyanidin equivalents respectively on dry matter basis) were found in Samastipur while the lowest from Patna (0.95 and 0.426 % leucocyanidin equivalent on dry matter basis). The different nutritional parameters were also found to be in variable concentration among different germplasms viz. total soluble protein ≈ 20–32 %, free amino acids ≈ 188–348 mg/100 g, starch ≈ 27–33 %, reducing sugars ≈ 85–188 mg/100 g, non reducing sugars ≈ 0.7–1.7 % and total soluble sugars ≈ 0.8–1.9 %.     

USP7 deubiquitinase promotes ubiquitin-dependent DNA damage signaling by stabilizing RNF168*

During DNA damage response (DDR), histone ubiquitination by RNF168 is a critical event, which orchestrates the recruitment of downstream DDR factors, e.g. BRCA1 and 53BP1. Here, we report USP7 deubiquitinase regulates the stability of RNF168. We showed that USP7 disruption impairs H2A and ultraviolet radiation (UVR)-induced γH2AX monoubiquitination, and decreases the levels of pBmi1, Bmi1, RNF168 and BRCA1. The effect of USP7 disruption was recapitulated by siRNA-mediated USP7 depletion. The USP7 disruption also compromises the formation of UVR-induced foci (UVRIF) and ionizing radiation-induced foci (IRIF) of monoubiquitinated H2A (uH2A) and polyubiquitinated H2AX/A, and subsequently affects UVRIF and IRIF of BRCA1 as well as the IRIF of 53BP1. USP7 was shown to physically bind RNF168 in vitro and in vivo. Overexpression of wild-type USP7, but not its interaction-defective mutant, prevents UVR-induced RNF168 degradation. The USP7 mutant is unable to cleave Ub-conjugates of RNF168 in vivo. Importantly, ectopic expression of RNF168, or both RNF8 and RNF168 together in USP7-disrupted cells, significantly rescue the formation of UVRIF and IRIF of polyubiquitinated H2A and BRCA1. Taken together, these findings reveal an important role of USP7 in regulating ubiquitin-dependent signaling via stabilization of RNF168.     

Development and molecular characterization of wheat--Aegilops kotschyi addition and substitution lines with high grain protein, iron, and zinc

Over two billion people, depending largely on staple foods, suffer from deficiencies in protein and some micronutrients such as iron and zinc. Among various approaches to overcome protein and micronutrient deficiencies, biofortification through a combination of conventional and molecular breeding methods is the most feasible, cheapest, and sustainable approach. An interspecific cross was made between the wheat cultivar 'Chinese Spring' and Aegilops kotschyi Boiss. accession 396, which has a threefold higher grain iron and zinc concentrations and about 33% higher protein concentration than wheat cultivars. Recurrent backcrossing and selection for the micronutrient content was performed at each generation. Thirteen derivatives with high grain iron and zinc concentrations and contents, ash and ash micronutrients, and protein were analyzed for alien introgression. Morphological markers, high molecular weight glutenin subunit profiles, anchored wheat microsatellite markers, and GISH showed that addition and substitution of homoeologous groups 1, 2, and 7 chromosomes of Ae. kotschyi possess gene(s) for high grain micronutrients. The addition of 1U/1S had high molecular weight glutenin subunits with higher molecular weight than those of wheat, and the addition of 2S in most of the derivatives also enhanced grain protein content by over 20%. Low grain protein content in a derivative with a 2S-wheat translocation, waxy leaves, and absence of the gdm148 marker strongly suggests that the gene for higher grain protein content on chromosome 2S is orthologous to the grain protein QTL on the short arm of group 2 chromosomes.     

Evaluation of hadacidin analogues

Several derivatives of hadacidin have been developed and evaluated for activity against adenylosuccinate synthetase.