Vaccination against Toxoplasmosis

The intracellular protozoan parasite Toxoplasma gondii can infect a wide range of animal species, and is one of the main causes of infectious abortion and perinatal mortality in sheep. In humans, the parasite can cause abortion and congenital infection, and fatal disease in immunosuppressed patients. In sheep, toxoplasmosis can be controlled by vaccination with a live, attenuated vaccine. However, since such a vaccine has practical disadvantages and is not acceptable for use in humans, various strategies to develop an effective subunit vaccine have been explored. The major surface antigen of T. gondii, named SAG1, is considered as a promising vaccine candidate. Equally as important as identification of protective antigens is the choice of adjuvant. The immunostimulating complex (iscom) is an adjuvant formulation that induces both humoral and cellular immune responses that are predominantly of type 1, and therefore is likely to be effective against intracellular parasites. The aim of the present study was to produce iscoms containing recombinant SAG1 (rSAG1) and to investigate their immunogenicity and protective capacity against T. gondii using a mouse model. SAG1 expressed in E. coli as a recombinant protein with a hexahistidyl (His6) tag was coupled to preformed iscom matrix (i.e. iscom particles without any antigen) using the affinity of the His6 tag to divalent anions. The matrix contained a chelating lipid and had been loaded with Ni2+ ions. Analytical density gradient centrifugation revealed that a substantial proportion of the SAG1 had bound to the matrix. To investigate the immunogenicity of the rSAG1 iscoms, mice were immunised twice and the cellular immune response examined by in vitro stimulation of spleen cells. Cells from three of four immunised mice proliferated significantly when exposed to rSAG1, whereas cells from only one of five mice were stimulated with T. gondii lysate. ELISA analysis revealed high antibody titres against rSAG1 but only low levels against T. gondii antigens. In two subsequent challenge experiments, three groups of mice were inoculated three times with either rSAG1 iscoms, iscom matrix, or PBS. The third immunisation resulted in substantially higher antibody titres against T. gondii antigen. After inoculation with the virulent RH strain all mice died without any significant differences in survival time between groups (p = 0.179). However, when the mice were inoculated orally with tissue cysts of the Tg-SweF1 strain, significantly lower numbers of brain cysts were found in mice immunised with rSAG1 iscoms than in mice injected with PBS (p < 0.05). In conclusion, although immunisation with rSAG1 iscoms did not protect mice from the lethal challenge infection, partial protection was induced as demonstrated by the reduction of brain cyst load after inoculation with an avirulent strain

Thermal Performance Analysis of a Newly Designed Circular Firewood Boiling Salt Stove

Different biomass stoves are introduced and distributed among people living in rural and urban areas, especially in developing countries. For salt crystal production in Thailand’s rural north-eastern area, open fire stoves are used in domestic and small productive activities. Their thermal efficiency is very low for converting heat into utilization energy. A new stove with a circular configuration was designed and constructed to consider its thermal efficiency and economics, which were compared with those from a traditional and an improved traditional stove. The obtained thermal efficiency of the newly designed stove was 14.77% higher than that of the improved stove and 81.45% higher than that of the traditional stove. For the same initial saline volume, the final amounts of salt crystals and salt flowers obtained from the newly designed stove was higher compared with those obtained from the improved stove and the traditional stove, respectively, resulting in a 69.25% shorter payback period

First report on the molecular detection and genetic diversity of Anaplasma marginale in healthy dairy cattle in Khon Kaen province, Thailand

Background and Aim: Bovine anaplasmosis (BA) is one of the most important diseases of ruminants worldwide, causing significant economic losses in the livestock industry due to the high morbidity and mortality in susceptible cattle herds. Anaplasma marginale is the main causative agent of BA occurring worldwide in tropical and subtropical regions. This study aimed to investigate the first molecular detection and genetic diversity of A. marginale in dairy cattle in Khon Kaen Province, Thailand. Materials and Methods: Blood samples were collected from 385 lactating cows from 40 dairy farms in five districts of Khon Kaen, regardless of age and health status. To detect A. marginale, all DNA preparations were used for molecular diagnosis using a single polymerase chain reaction with the msp4 gene target. A phylogenetic tree was constructed from the msp4 gene sequences using molecular genetic characterization. Genetic diversity was calculated as haplotype diversity, haplotype number, number of nucleotide differences, nucleotide diversity, and average number of nucleotide differences. Results: The overall prevalence of A. marginale was 12.72% (49/385). The highest prevalence (17.19%) was found in Ubolratana district, followed by Muang, Kranuan, Khao Suan Kwang, and Nam Phong districts (14.94%, 14.74%, 13.79%, and 3.70%, respectively). Phylogenetic analysis showed that A. marginale was closely related to isolates from Australia (98.96%), China (99.68%), Spain (99.74%), and the USA (99.63%). Conclusion: The molecular prevalence of BA in dairy cattle is the first to be observed in this area, and the genetic variability with separated clusters shown in the msp4 gene of A. marginale revealed species variation in dairy cattle. This significant genetic diversity contributes to the understanding of the diversity of A. marginale and will be important for the control and prevention of A. marginale in dairy cattle

Solid-state flurbiprofen and methyl-β-cyclodextrin inclusion complexes prepared using a single-step, organic solvent-free supercritical fluid process

The aim of this study was to enhance the apparent solubility and dissolution properties of flurbiprofen through inclusion complexation with cyclodextrins. Especially, the efficacy of supercritical fluid technology as a preparative technique for the preparation of flurbiprofen-methyl–β–cyclodextrin inclusion complexes was evaluated. The complexes were prepared by supercritical carbon dioxide processing and were evaluated by solubility, differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, practical yield, drug content estimation and in vitro dissolution studies. Computational molecular docking studies were conducted to study the possibility of molecular arrangement of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin. The studies support the formation of stable molecular inclusion complexes between the drug and cyclodextrin in a 1:1 stoichiometry. In vitro dissolution studies showed that the dissolution properties of flurbiprofen were significantly enhanced by the binary mixtures prepared by supercritical carbon dioxide processing. The amount of flurbiprofen dissolved into solution alone was very low with 1.11 ± 0.09% dissolving at the end of 60 min, while the binary mixtures processed by supercritical carbon dioxide at 45 °C and 200 bar released 99.39 ± 2.34% of the drug at the end of 30 min. All the binary mixtures processed by supercritical carbon dioxide at 45 °C exhibited a drug release of more than 80% within the first 10 min irrespective of the pressure employed. The study demonstrated the single step, organic solvent-free supercritical carbon dioxide process as a promising approach for the preparation of inclusion complexes between flurbiprofen and methyl–β–cyclodextrin in solid-state

Thermal Insulation and Strength Characteristics of Refractory Incorporating Natural Silica

This work emphasizes on the studying of using silica to develop for the production of refractory materials. Materials are tested at the cured times of 7, 14 and 28 days. Results show that the cold crushing strength, flexural strength and bulk density increase with increasing cured times. On the other hand, the permanent linear change (PLC) decreases with increasing cured times. It is also found that adding more silica contents can increase the durability of cracking property due to temperature changing. This study concludes that the silica refractory materials (SRM) shows the enough quality to produce as the refractory material, type of the Conventional Cast/Pound (815 °C) for the agroindustry using the thermal energy of Thailand

Preparation and Characterization of Nifedipine-Loaded Dry Medium Internal-Phase Emulsions (Dry MIPEs) to Improve Cellular Permeability

A nifedipine (NP) dry emulsion was fabricated by the adsorption of medium internal-phase emulsions (MIPEs). Simple homogenizers were first used to mix conventional liquid MIPEs, and then a microfluidizer was used to reduce the resulting emulsions’ droplet sizes. The dry MIPEs (solid) were produced by adsorbing the emulsions onto solid carriers with a high surface area. The dry MIPEs were diluted in a simulated gastric fluid under gentle agitation to form emulsions. The diluted dry MIPEs were divided into three groups based on an NP content of 0.3%, 0.5%, and 0.7%, with sizes of 5026–5404 nm, 2583–3233 nm, and 1318–1618 nm in diameter, respectively. Powder X-ray diffraction (PXRD) measurements and differential scanning calorimetry (DSC) were used to characterize the physical properties of the dry MIPEs. The samples contained 0.5% or 0.7% drug, 2–4% surfactant, and 8–16% oil (5RH2/8, 7RH2/8, and 7RH4/16) and showed the characteristic peak for NP. No NP peak was observed in formulations with 0.3% NP and any oil-phase content (3RH2/8, 3RH4/16, and 3RH8/32). The formulations with 0.5% drug, 4–8% surfactant, 16–32% oil (5RH4/16 and 5RH8/32) and those with 0.7% drug, 8% surfactant, and 32% oil (7RH8/32) also did not show the peak for NP. These findings demonstrated that microfluidization improved the solubility of NP in the formulations. The subsequent drug dissolution results were consistent with the DSC thermogram and PXRD pattern results. 3RH2/8, 3RH4/16, 3RH8/32, 5RH4/16, 5RH8/32, and 7RH8/32 were completely dissolved and showed higher dissolved NP amounts than 5RH2/8, 7RH2/8, 7RH4/16, and NP powder. The lowest mean dissolution time was for 7RH8/32 (13.31 ± 0.87 min). Caco-2 cells were used to determine drug uptake, and 7RH8/32 showed the maximum intracellular uptake (10.89%). After storage under accelerated and normal conditions (3 and 6 months), the selected formulations remained stable. The developed formulations can be used to improve NP solubility and absorption