Sulfamethizole attenuates poloxamer 407-induced atherosclerotic neointima formation via inhibition of mTOR in C57BL/6 mice

Mammalian target of Rapamycin C1 (mTORC1) inhibition limits plaque progression in atherosclerosis. The present study evaluated the protective effect of sulfamethizole on poloxamer 407-induced atherosclerotic neointima formation in C57BL/6 mice via mTOR inhibition. Poloxamer 407 (P-407) (0.5 g/kg body weight) was administered intraperitoneally to male C57BL/6 mice every third day for 148 days to induce chronic hyperlipidemia. From Day 121 to 148, animals were additionally administered Sulfamethizole (5, 10, and 50 mg/kg, p.o.), Rapamycin (0.5 mg/kg, positive control), or vehicle (1 ml/kg). Plasma lipid levels were measured on Days 120 and 148. Upon sacrifice, histological studies were performed, and aortic tissue interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and mTOR levels were evaluated. A molecular docking study was carried out to mimic the interaction of sulfamethizole with mTOR protein. Chronic P-407 administration significantly (p < 0.001) elevated plasma lipid levels, compared with those of the normal control group. Chronic hyperlipidemia resulted in increased tunica intima thickness, collagen deposition, and IL-6, TNF-α, and mTOR levels. Treatment with Sulfamethizole attenuated these parameters significantly in a dose-dependent manner. Molecular docking studies showed a significant interaction of Sulfamethizole with mTOR. In conclusion, this study suggests that sulfamethizole significantly limits poloxamer 407-induced atherosclerotic neointima formation in C57BL/6 mice via mTOR inhibition.     

Hybrid Adeno-Associated Viral Vectors Utilizing Transposase-Mediated Somatic Integration for Stable Transgene Expression in Human Cells

Recombinant adeno-associated viral (AAV) vectors have been shown to be one of the most promising vectors for therapeutic gene delivery because they can induce efficient and long-term transduction in non-dividing cells with negligible side-effects. However, as AAV vectors mostly remain episomal, vector genomes and transgene expression are lost in dividing cells. Therefore, to stably transduce cells, we developed a novel AAV/transposase hybrid-vector. To facilitate SB-mediated transposition from the rAAV genome, we established a system in which one AAV vector contains the transposon with the gene of interest and the second vector delivers the hyperactive Sleeping Beauty (SB) transposase SB100X. Human cells were infected with the AAV-transposon vector and the transposase was provided in trans either by transient and stable plasmid transfection or by AAV vector transduction. We found that groups which received the hyperactive transposase SB100X showed significantly increased colony forming numbers indicating enhanced integration efficiencies. Furthermore, we found that transgene copy numbers in transduced cells were dose-dependent and that predominantly SB transposase-mediated transposition contributed to stabilization of the transgene. Based on a plasmid rescue strategy and a linear-amplification mediated PCR (LAM-PCR) protocol we analysed the SB100X-mediated integration profile after transposition from the AAV vector. A total of 1840 integration events were identified which revealed a close to random integration profile. In summary, we show for the first time that AAV vectors can serve as template for SB transposase mediated somatic integration. We developed the first prototype of this hybrid-vector system which with further improvements may be explored for treatment of diseases which originate from rapidly dividing cells.     

Investigation of Thermal and Viscoelastic Properties of Polymers Relevant to Hot Melt Extrusion,IV: Affinisol™ HPMC HME Polymers

Most cellulosic polymers cannot be used as carriers for preparing solid dispersion of drugs by hot melt extrusion (HME) due to their high melt viscosity and thermal degradation at high processing temperatures. Three HME-grade hydroxypropyl methylcelluloses, namely Affinisol™ HPMC HME 15 cP, Affinisol™ HPMC HME 100 cP, and Affinisol™ HPMC HME 4 M, have recently been introduced by The Dow Chemical Co. to enable the preparation of solid dispersion at lower and more acceptable processing temperatures. In the present investigation, physicochemical properties of the new polymers relevant to HME were determined and compared with that of Kollidon^® VA 64. Powder X-ray diffraction (PXRD), modulated differential scanning calorimetry (mDSC), thermogravimetric analysis (TGA), moisture sorption, rheology, and torque analysis by melt extrusion were applied. PXRD and mDSC showed that the Affinisol™ polymers were amorphous in nature. According to TGA, the onset of degradation for all polymers was >220°C. The Affinisol™ polymers exhibited less hygroscopicity than Kollidon^® VA 64 and another HPMC polymer, Methocel™ K100LV. The complex viscosity profiles of the Affinisol™ polymers as a function of temperature were similar. The viscosity of the Affinisol™ polymers was highly sensitive to the shear rate applied, and unlike Kollidon^® VA 64, the viscosity decreased drastically when the angular frequency was increased. Because of the very high shear rate encountered during melt extrusion, Affinisol™ polymers showed capability of being extruded at larger windows of processing temperatures as compared to that of Kollidon^® VA 64.KEY WORDS: Affinisol™ HPMC HME, hot melt extrusion, hydroxypropyl methylcellulose, solid dispersion, thermal analysis, viscosity     

Molecular docking analysis of Clostridium perfringens beta toxin model with potential inhibitors from the ZINC database

Beta toxin from Clostridium perfringens after being secreted in gut is capable of causing necrotic enteritis in humans and several other animal species and does not respond to routinely used antibiotics. Therefore, there is a need to design an effective inhibitor for the Clostridium perfringens beta toxin (CPB) using cutting edge drug discovery technologies. Hence, potential CPB inhibitors were identified using computer aided screening of compounds from the ZINC database. Further, we document the molecular docking analysis of Clostridium perfringens beta toxin model (that revealed 4 binding pockets, A-D) with the identified potential inhibitors. We show that ZINC291192 [N-[(1-methylindol-3-yl) methyl eneamino]-7,10-dioxabicyclo[4.4.0]deca-2,4,11-triene-8- carboxamide] has optimal binding features with calculated binding energy of -10.38 kcal/mol and inhibition constant of 24.76 nM for further consideration.     

Sustained release implants of chloroquine phosphate for possible use in chemoprophylaxis of malaria

Implants of chloroquine phosphate (CQP) using biodegradable polymer, gelatin (G) and cross-linked gelatin (CLG) were prepared and evaluated to assess their physicochemical properties and in vitro release profile. The mechanism and kinetics of release were studied to correlate the release phenomenon with the formulation parameters. Out of many batches of the implants investigated, the implant prepared with 20% gelatin at 2:1 drug polymer ratio, 10% crosslinking agent and 2% plasticizer (Batch J) was found to provide optimum release behavior conforming to the requirements of a long term implant for a week. In vivo studies conducted on albino rats showed consistent therapeutic blood level over a period of 7 days. Mean residence time (MRT) of the drug released in the body, calculated as the ratio of the area under the first moment curve (AUMC) to area under concentration time curve (AUC) was 72 hr for implant against 2.42 hr for subcutaneous injection.     

Analysis of plastid DNA-like sequences within the nuclear genomes of higher plants

A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.      

Incidence and levels of fumonisin contamination in Colombian corn and corn products

A survey was conducted to determine the levels of fumonisins B1 and B2 in corn and corn-based products available in Colombia for human and animal consumption. A total of 120 samples were analyzed by acetonitrile-water extraction, cleanup with a strong-anion-exchange column, and liquid chromatography with o-phthaldialdehyde-2-mercaptoethanol derivatization and fluorescence detection. The samples of corn and corn-based products for animal intake were taken at different feed manufacturing plants, whereas the samples used for human foods where purchased from local retail stores. The number of positive samples for fumonisin B1 was 20.0% higher in corn and corn-based products for animal intake (75.0%) than in corn and corn-based products for human consumption (55.0%). The levels of fumonisin B1 were also higher in corn and corn-based products for animal intake (mean = 694 μg/kg; range = 32–2964 μg/kg), than in corn and corn-based products for human intake (mean = 218 μg/kg; range = 24–2170 μg/ kg). The incidence and levels of fumonisin B2 were lower than those for fumonisin B1. Corn and corn-based products for animal consumption had an incidence of fumonisin B2 of 58.3%, with a mean value of 283 μg/kg, and a range of 44–987 μg/kg. The incidence of fumonisin B2 in corn-based products for human intake was 35.0%, with a mean value of 118 μg/kg and a range of 21–833 μg/kg. The highest incidence and levels of fumonisins were found in samples of hominy feed, with concentrations ranging from 86 to 2964 μg/kg fumonisin B1 and 57 to 987 μg/kg fumonisin B2.     

Synthesis and in vitro antibacterial activity of novel methylamino piperidinyl oxazolidinones

Design and synthesis of a few novel methylamino piperidinyl substituted oxazolidinones are reported. Their antibacterial activities have been evaluated in a MIC assay against broader panel of both susceptible and resistant Gram-positive strains. (S)-N-{3-[3-Fluoro-4-(methyl-{1-[3-(5-nitrofuran-2-yl)-acryloyl]-piperidin-4-yl}-amino)-phenyl]-2-oxo-oxazolidin-5-ylmethyl}-acetamide 4i has shown comparable antibacterial activity to linezolid and eperezolid in the MIC assay, additionally compound 4i showed good antibacterial activity with an in vitro MIC value of 2-4 microg/mL against linezolid resistant Staphylococcus aureus (linezolid 16 microg/mL).