Inhibition of lipid peroxide decomposition by compounds which bind with cytochrome p-450

The kinetics of lipid peroxide decomposition catalysed by microsomal enzymes and inhibited by SKF-525 A, hexobarbital, phenobarbital and aniline were investigated. The results indicate that the in vitro interaction of hexobarbital and SKF-525 A (type I binding compounds) with microsomal cytochrome p-450 inhibits the peroxidase activity while the in vitro interaction of aniline (type II binding compound) only slightly affect the peroxidase activity. It is suggested that LAHPO and type I binding compounds are competing for the hydrophobic binding site on cytochrome p-450, while type II binding compounds such as aniline negate electron transfer non-competitively by combining with the heme.     

Identification of mitogen-activated protein/extracellular signal-responsive kinase kinase 2 as a novel partner of the scaffolding protein human homolog of disc-large

Human disc-large homolog (hDlg), also known as synapse-associated protein 97, is a scaffold protein, a member of the membrane-associated guanylate kinase family, implicated in neuronal synapses and epithelial-epithelial cell junctions whose expression and function remains poorly characterized in most tissues, particularly in the vasculature. In human vascular tissues, hDlg is highly expressed in smooth muscle cells (VSMCs). Using the yeast two-hybrid system to screen a human aorta cDNA library, we identified mitogen-activated protein/extracellular signal-responsive kinase (ERK) kinase (MEK)2, a member of the ERK cascade, as an hDlg binding partner. Site-directed mutagenesis showed a major involvement of the PSD-95, disc-large, ZO-1 domain-2 of hDlg and the C-terminal sequence RTAV of MEK2 in this interaction. Coimmunoprecipitation assays in both human VSMCs and human embryonic kidney 293 cells, demonstrated that endogenous hDlg physically interacts with MEK2 but not with MEK1. Confocal microscopy suggested a colocalization of the two proteins at the inner layer of the plasma membrane of confluent human embryonic kidney 293 cells, and in a perinuclear area in human VSMCs. Additionally, hDlg also associates with the endoplasmic reticulum and microtubules in these latter cells. Taken together, these findings allow us to hypothesize that hDlg acts as a MEK2-specific scaffold protein for the ERK signaling pathway, and may improve our understanding of how scaffold proteins, such as hDlg, differentially tune MEK1/MEK2 signaling and cell responses.     

Improved Oral Bioavalability of Mebudipine Upon Administration in PhytoSolve and Phosal-Based Formulation (PBF)

The aim of this investigation was to examine the efficacy of PhytoSolve and Phosal-based formulation (PBF) to enhance the oral bioavailability of mebudipine, which is a poorly water-soluble calcium channel blocker. The solubility of mebudipine in various oils was determined. PhytoSolve was prepared with a medium-chain triglyceride (MCT) oil (20%), soybean phospholipids (5%), and a 70% fructose solution (75%). The influence of the weight ratio of Phosal 50PG to glycerol in PBF on the mean globule size was studied with dynamic light scattering. The optimized formulation was evaluated for robustness toward dilution, transparency, droplet size, and zeta potential. The in vivo oral absorption of different mebudipine formulations (PhytoSolve, PBF, oily solution, and suspension) were evaluated in rats. The optimized PBF contained Phosal 50PG/glycerol in a 6:4 ratio (w/w). The PBF and PhytoSolve formulations were miscible with water in any ratio and did not demonstrate any phase separation or drug precipitation over 1 month of storage. The mean particle size of PhytoSolve and PBF were 138.5 ± 9.0 and 74.4 ± 2.5 nm, respectively. The in vivo study demonstrated that the oral bioavailability of PhytoSolve and PBF in rats was significantly higher than that of the other formulations. The PhytoSolve and PBF formulations of mebudipine are found to be more bioavailable compared with suspension and oily solutions during an in vivo study in rats. These formulations might be new alternative carriers that increase the oral bioavailability of poorly water-soluble molecules, such as mebudipine.KEY WORDS: mebudipine, oral bioavailability, Phosal 50PG, PhytoSolve     

Substance P analogues function as bombesin receptor antagonists and inhibit small cell lung cancer clonal growth

Human small cell lung cancer (SCLC) produces and secretes BN/GRP (bombesin/gastrin releasing peptide). Because BN stimulates the growth of SCLC cells and these cells have receptors for BN-like peptides, it is important to define agents which disrupt this self-promoting autocrine growth cycle. Here, substance P analogues were evaluated as BN receptor antagonists using SCLC cell lines. (D-Arg¹, D-Pro², D-Trp^7,9, Leu¹¹) substance P [(APTTL)SP] was one of the more potent analogues tested in inhibiting BN-like peptide receptor binding with an IC₅₀ value of 1 μM. Micromolar concentrations of (APTTL)SP antagonized BN receptor mediated elevation of cytosolic Ca²⁺ levels and decreased the colony formation in soft agarose. These data suggest that SP analogues function as SCLC BN receptor antagonists and may be useful in disrupting the autocrine growth function of BN-like peptides.     

Mutual Exclusivity of Hyaluronan and Hyaluronidase in Invasive Group A Streptococcus

A recent analysis of group A Streptococcus (GAS) invasive infections in Australia has shown a predominance of M4 GAS, a serotype recently reported to lack the antiphagocytic hyaluronic acid (HA) capsule. Here, we use molecular genetics and bioinformatics techniques to characterize 17 clinical M4 isolates associated with invasive disease in children during this recent epidemiology. All M4 isolates lacked HA capsule, and whole genome sequence analysis of two isolates revealed the complete absence of the hasABC capsule biosynthesis operon. Conversely, M4 isolates possess a functional HA-degrading hyaluronate lyase (HylA) enzyme that is rendered nonfunctional in other GAS through a point mutation. Transformation with a plasmid expressing hasABC restored partial encapsulation in wild-type (WT) M4 GAS, and full encapsulation in an isogenic M4 mutant lacking HylA. However, partial encapsulation reduced binding to human complement regulatory protein C4BP, did not enhance survival in whole human blood, and did not increase virulence of WT M4 GAS in a mouse model of systemic infection. Bioinformatics analysis found no hasABC homologs in closely related species, suggesting that this operon was a recent acquisition. These data showcase a mutually exclusive interaction of HA capsule and active HylA among strains of this leading human pathogen.     

Distribution,degree of damage and risk of spread of Trioza erytreae (Hemiptera: Triozidae) in Kenya

The African citrus triozid (ACT), Trioza erytreae Del Guercio, is a destructive pest particularly on citrus, and vectors, “Candidatus” Liberibacter africanus (CLaf), which is the causal agent of the African citrus greening disease. Our study seeks to establish the distribution and host‐plant relationship of ACT across citrus production areas in Kenya. We also modelled the risk of spread using the maximum entropy modelling algorithm with known occurrence data. Our results infer that ACT is widely distributed and causes severe damage to four alternative host plants belonging to the family Rutaceae. The adults, immature stages (eggs and nymphs), galls and the percentage of infested leaves were significantly higher in shaded than unshaded trees. However, adult ACTs preferred Kenyan highlands to Victoria Lake and coastal regions. The average area under the curve of the model predictions was 0.97, indicating an optimal model performance. The environmental variables that most influenced the prediction were the precipitation of wettest quarter, precipitation of wettest month, mean diurnal range, temperature seasonality and mean temperature of the coldest quarter. The current prediction of ACT exceeded its existing range, especially in the Western, Nyanza, Central, Rift valley and Eastern regions of Kenya. The model predicted a contraction of suitable habitats for a potential spread in 2040 with an inland shift to higher altitudes in the cooler regions. The potential for further expansion to climatically suitable areas was more pronounced for the 2080 forecast. These findings provide relevant information to improve monitoring/surveillance and designing IPM strategies to limit its spread and damage.     

Fusobacterium nucleatum and colorectal cancer: A mechanistic overview

Colorectal cancer (CRC) is the third most prevalent cancer in the world. There are many risk factors involved in CRC. According to recent findings, the tumor microenvironment and feces samples of patients with CRC are enriched by Fusobacterium nucleatum. Thus, F. nucleatum is proposed as one of the risk factors in the initiation and progression of CRC. The most important mechanisms of Fusobacterium nucleatum involved in CRC carcinogenesis are immune modulation (such as increasing myeloid-derived suppressor cells and inhibitory receptors of natural killer cells), virulence factors (such as FadA and Fap2), microRNAs (such as miR-21), and bacteria metabolism. The aim of this review was to evaluate the mechanisms underlying the action of F. nucleatum in CRC.     

The Combined Deletion of S6K1 and Akt2 Deteriorates Glycemic Control in a High-Fat Diet

Signaling downstream of mechanistic target of rapamycin complexes 1 and 2 (mTORC1 and mTORC2) controls specific and distinct aspects of insulin action and nutrient homeostasis in an interconnected and as yet unclear way. Mice lacking the mTORC1 substrate S6 kinase 1 (S6K1) maintain proper glycemic control with a high-fat diet. This phenotype is accompanied by insulin hypersensitivity, Akt- and AMP-activated kinase upregulation, and increased lipolysis in adipose tissue and skeletal muscle. Here, we show that, when S6K1 inactivation is combined with the deletion of the mTORC2 substrate Akt2, glucose homeostasis is compromised due to defects in both insulin action and β-cell function. After a high-fat diet, the S6K1(-/-) Akt2(-/-) double-mutant mice do not become obese, though they are severely hyperglycemic. Our data demonstrate that S6K1 is required for pancreatic β-cell growth and function during adaptation to insulin resistance states. Strikingly, the inactivation of two targets of mTOR and phosphatidylinositol 3-kinase signaling is sufficient to reproduce major hallmarks of type 2 diabetes.     

Fine needle aspiration in aspergilloma of frontal sinus: a case report

BACKGROUND: The increased incidence of fungal diseases in humans is most likely due to indiscriminate use of broad-spectrum antibiotics and increased numbers of immunocompromised patients. Although Aspergillus species are ubiquitous and normally nonpathogenic, they can be opportunistic pathogens in immunocompromised individuals. CASE: A 22-year-old immunocompetent man presented with a gradually increasing subcutaneous swelling near the root of his nose for previous 6 months. The mass was soft to firm, solid, nontender and immobile. There was no superficial skin ulceration and no local signs of inflammation. Proptosis of the left eye was present without any visual impairment. An osteolytic lesion that was contiguous with the subcutaneous mass, with the opacities of both the fontal sinuses was observed radiographically. Fine needle aspiration cytology (FNAC) demonstrated presence of branching hyphae in the cytoplasm of multinucleated giant cells along with mixed inflammatory cells. The species was identified by culture in Sabouraud's agar with chloramphenicol and wet mount with lactophenol cotton blue stain. CONCLUSION: Aspergillosis can remain dormant over a long period. Although uncommon, it can occur in immunocompetent patients. FNA is a very useful tool in establishing the diagnosis     

Vaccination with Recombinant RNA Replicon Particles Protects Chickens from H5N1 Highly Pathogenic Avian Influenza Virus

Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 not only cause a devastating disease in domestic chickens and turkeys but also pose a continuous threat to public health. In some countries, H5N1 viruses continue to circulate and evolve into new clades and subclades. The rapid evolution of these viruses represents a problem for virus diagnosis and control. In this work, recombinant vesicular stomatitis virus (VSV) vectors expressing HA of subtype H5 were generated. To comply with biosafety issues the G gene was deleted from the VSV genome. The resulting vaccine vector VSV*ΔG(HA) was propagated on helper cells providing the VSV G protein in trans. Vaccination of chickens with a single intramuscular dose of 2×10⁸ infectious replicon particles without adjuvant conferred complete protection from lethal H5N1 infection. Subsequent application of the same vaccine strongly boosted the humoral immune response and completely prevented shedding of challenge virus and transmission to sentinel birds. The vaccine allowed serological differentiation of infected from vaccinated animals (DIVA) by employing a commercially available ELISA. Immunized chickens produced antibodies with neutralizing activity against multiple H5 viruses representing clades 1, 2.2, 2.5, and low-pathogenic avian influenza viruses (classical clade). Studies using chimeric H1/H5 hemagglutinins showed that the neutralizing activity was predominantly directed against the globular head domain. In summary, these results suggest that VSV replicon particles are safe and potent DIVA vaccines that may help to control avian influenza viruses in domestic poultry.