Immunization of rabbits with recombinant Clostridium perfringens alpha toxins CPA-C and CTB-CPA-C in a bicistronic design expression system confers strong protection against challenge.

The Clostridium perfringens alpha toxin (CPA), encoded by the plc gene, is the causative pathogen of gas gangrene, which is a lethal infection. In this study, we used an E. coli system for the efficient production of recombinant proteins and developed a bicistronic design (BCD) expression construct consisting of two copies of the C-terminal (247-370) domain of the alpha toxin (CPA-C) in the first cistron, followed by Cholera Toxin B (CTB) linked with another two copies of CPA-C in the second cistron that is controlled by a single promoter. Rabbits were immunized twice with purified proteins (rCPA-C rCTB-CPA-C) produced in the BCD expression system, with an inactivated recombinant E. coli vaccine (RE), C. perfringens formaldehyde-inactivated alpha toxoid (FA-CPA) and C. perfringensl-lysine/formaldehyde alpha toxoid (LF-CPA) vaccines. Following the second vaccination, 0.1 mL of pooled sera of the RE-vaccinated rabbits could neutralize 12× mouse LD100 (100% lethal dose) of CPA, while that of the rCPA-C rCTB-CPA-C-vaccinated rabbits could neutralize 6× mouse LD100 of CPA. Antibody titers against CPA were also assessed by ELISA, reaching titers as high as 1:2048000 in the RE group; this was significantly higher compared to the C. perfringens alpha toxoid vaccinated groups (FA-CPA and LF-CPA). Rabbits from all vaccinated groups were completely protected from a 2× rabbit LD100 of CPA challenge. These results demonstrate that the recombinant proteins are able to induce a strong immune responses, indicating that they may be potentially utilized as targets for novel vaccines specifically against the C. perfringens alpha toxin.

Association of visual hallucinations with very mild degenerative dementia due to dementia with Lewy bodies.

BACKGROUND AND PURPOSE: Complex, well-formed, and detailed visual hallucinations (VHs) are among the core clinical features of dementia with Lewy bodies (DLB). We investigated the diagnostic value of VHs in different types of very mild degenerative dementia. METHODS: Participants were required to complete a structured interview form recording their basic data, clinical history, neuropsychological tests, and neuropsychiatric symptoms. Basic demographic characteristics of the participants were summarized and compared. The frequency and association factors of VHs were compared among three major degenerative dementia groups, namely, Alzheimer's disease (AD), Parkinson's disease dementia (PDD), and DLB. RESULTS: A total of 197 patients with dementia and a clinical dementia rating of 0.5 were investigated, comprising 124 with AD, 35 with PDD, and 38 with DLB. A significantly higher frequency of VHs was found in the DLB group compared with the other groups (DLB, PDD, and AD = 31.6%, 11.4%, and 4.0%; p < 0.001). A multivariable logistic regression test for associations of positive VHs revealed that DLB was the only independently predictive factor (odds ratio: 13.62; p < 0.001). CONCLUSION: Our findings revealed a high diagnostic value of VHs in very mild degenerative dementia. VHs in this stage of dementia were significantly associated with DLB, and more than 30% of patients with very mild dementia caused by DLB presented with VHs.

pH-sensitive micelles for the intracellular co-delivery of curcumin and Pluronic L61 unimers for synergistic reversal effect of multidrug resistance.

Pluronic L61 unimers, which are biomacromolecular modulators, and curcumin, a small-molecule modulator, were co-formulated into pH-sensitive micelles to reveal the full synergistic potential of combination drug treatments to reverse multidrug resistance (MDR). Compared to monotherapy, combined therapy significantly improved the cytotoxicity, cellular uptake and apoptotic effects of doxorubicin (DOX) against MCF-7/ADR cells. In mechanistic studies, both L61 and curcumin enhanced the cytotoxic effect by acting on mitochondrial signalling pathways. The compounds selectively accumulated in the mitochondria and disabled the mitochondria by dissipating the mitochondrial membrane potential, decreasing the ATP levels, and releasing cytochrome c, which initiated a cascade of caspase-9 and caspase-3 reactions. Furthermore, both curcumin and L61 down-regulated the expression and function of P-gp in response to drug efflux from the MCF-7/ADR cells. In the MCF-7/ADR tumour-bearing mouse model, intravenous administration of the combined therapy directly targeted the tumour, as revealed by the accumulation of DiR in the tumour site, which led to a significant inhibition of tumour growth without measurable side effects. In conclusion, co-formulation consisting of L61 and curcumin in pH-sensitive micelles induced significant synergistic effects on the reversal of MDR. Therefore, the intracellular co-delivery of various MDR modulators has great potential to reverse MDR in tumours.