A serological Survey of Brucella spp., Salmonella spp., Toxoplasma gondii and Trichinella spp. in Iberian Fattening Pigs Reared in Free‐Range Systems

Zoonotic agents such as Brucella spp., Salmonella spp., Toxoplasma gondii and Trichinella spp., all considered high‐risk zoonotic pathogens by the European Food Safety Agency (EFSA), may cause no symptoms of infection in free‐range pigs yet still have a significant public health impact. A serological survey was therefore performed to determine the history of occurrence of these pathogens in such pigs in southern Spain. A total of 709 serum samples were collected at abattoir from pigs from 79 farms and analysed for specific antibodies against the above pathogens using commercially available ELISA kits. Encysted Trichinella spp. larvae were also sought following the artificial digestion method of diaphragm pillar muscle. The results showed Salmonella spp. to be widely distributed among the sampled herds [73.42%, 95% confidence interval (CI₉₅) 65.6–81.78] and Toxoplasma gondii to be present in over half (58.23%, CI₉₅ 47.33–69.07). The seroprevalence of Brucella spp. was very low (3.8%, CI₉₅ 0.18–7.42), and antibodies against Trichinella spp. were not detected. No encysted Trichinella spp. larvae were microscopically detected.     

Inclusion of a universal tetanus toxoid CD4 T cell epitope P2 significantly enhanced the immunogenicity of recombinant rotavirus ΔVP8* subunit parenteral vaccines

Currently available live oral rotavirus vaccines, Rotarix^® and RotaTeq^®, are highly efficacious in developed countries. However, the immunogenicity and efficacy of such vaccines in some developing countries are low. We reported previously that bacterially-expressed rotavirus ΔVP8* subunit vaccine candidates with P[8], P[4] or P[6] specificity elicited high-titer virus neutralizing antibodies in animals immunized intramuscularly. Of note was the finding that antibodies induced with the P[8]ΔVP8* vaccine neutralized both homotypic P[8] and heterotypic P[4] rotavirus strains to high titer. To further improve its vaccine potential, a tetanus toxoid universal CD4⁺ T cell epitope P2 was introduced into P[8] or P[6]ΔVP8* construct. The resulting recombinant fusion proteins expressed in Escherichia coli were of high solubility and were produced with high yield. Two doses (10 or 20 μg/dose) of the P2-P[8]ΔVP8* vaccine or P2-P[6]ΔVP8* vaccine with aluminum phosphate adjuvant elicited significantly higher geometric mean homologous neutralizing antibody titers than the vaccines without P2 in intramuscularly immunized guinea pigs. Interestingly, high levels of neutralizing antibody responses induced in guinea pigs with 3 doses of the P2-P[8]ΔVP8* vaccine persisted for at least 6 months. Furthermore, in the gnotobiotic piglet challenge study, three intramuscular doses (50 μg/dose) of the P2-P[8]ΔVP8* vaccine with aluminum phosphate adjuvant significantly delayed the onset of diarrhea and significantly reduced the duration of diarrhea and the cumulative diarrhea score after oral challenge with virulent human rotavirus Wa (G1P[8]) strain. The P2-P[8]ΔVP8* vaccine induced serum virus neutralizing antibody and VP4-specific IgG antibody production prechallenge, and primed the pigs for higher antibody and intestinal and systemic virus-specific IFN-γ producing CD4⁺ T cell responses postchallenge. These two subunit vaccines could be used at a minimum singly or preferably in bivalent formulation to provide antigenic coverage of most of the G types of global importance.     

川芎嗪对离体豚鼠气道平滑肌的效应及机制研究

目的：探讨川芎嗪( ligustrazine,LIG)对离体豚鼠气道平滑肌( airway smooth muscle,ASM)的效应及机制。方法取正常豚鼠支气管,制作成气管螺旋条,随机分成LIG组、LIG+普萘洛尔组、LIG+阿托品组、LIG+硝苯地平组、LIG+格列苯脲组、对照组。分别观察ASM在静息张力下以及组胺所致的高张力下,各组不同LIG浓度对ASM的效应并比较各组间ASM舒张率。结果(1) LIG对离体豚鼠ASM静息张力以及组胺所致的高张力均具有舒张作用。(2)离体豚鼠ASM在静息张力下,与LIG组比较,LIG+普萘洛尔组在LIG浓度10-7~10-6．5 mol/L时,舒张作用明显受到拮抗( P <0．05)。 LIG +阿托品组、LIG+格列苯脲组在LIG浓度10-7．5~10-3 mol/L时,舒张作用没有明显差别(P>0．05)。 LIG+硝苯地平组在LIG浓度10-6~10-4 mol/L时,舒张作用明显加强( P<0．05)。(3)离体豚鼠ASM在组胺所致的高张力下,与LIG组比较,LIG+普萘洛尔组在LIG浓度10-6.5~10-5 mol/L时,舒张作用明显受到拮抗( P<0．05);LIG+阿托品组、LIG+格列苯脲组在LIG浓度10-8~10-3 mol/L时,舒张作用没有明显差别( P>0．05);LIG+硝苯地平组在LIG浓度10-6.5~10-5 mol/L时,舒张作用明显加强(P<0．05)。结论 LIG可对离体豚鼠ASM静息张力以及组胺所致的高张力产生明显的舒张作用,其效应的产生可能与竞争性激动β2受体以及抑制Ca2+内流有关,这为临床应用川芎嗪治疗支气管哮喘提供了理论依据。     

Allogeneic Stem Cells From Deciduous Teeth in Treatment for Periodontitis in Miniature Swine

Background: Regeneration of lost periodontium in periodontitis is a challenge in that alveolar bone, cementum, and periodontal ligament need to be restored to their original architecture. Stem cells from exfoliated deciduous teeth (SHEDs) appear to be an attractive candidate for periodontium tissue regeneration. Previously, the authors successfully regenerated periodontal defects using autologous and allogeneic periodontal ligament stem cells (PDLSCs). The purpose of the present study is to investigate the ability of allogeneic SHEDs to regenerate lost periodontium in a swine periodontitis model. Methods: Animal models of periodontitis were established in miniature pigs, and allogeneic stem cells were isolated from miniature pig deciduous teeth (SPDs). The animal models were treated with SPDs plus hydroxyapatite/tricalcium phosphate (HA/TCP). Allogeneic PDLSCs plus HA/TCP or HA/TCP alone were set as positive control or control, respectively. Clinical assessments, computed tomography (CT) scanning, and histologic examination were used to evaluate the outcome of tissue regeneration. Results: Clinical indices including probing depth, gingival recession, and attachment loss showed significant restoration in the SPD and PDLSC treatment groups, compared to the HA/TCP group 12 weeks post‐transplantation. Meanwhile, CT scans showed that 75% of the samples had successful hard‐tissue regeneration in both PDLSC and SPD groups, compared to the HA/TCP group, where the success rate was only 25%. In addition, histologic examination demonstrated that SPD and PDLSC treatment brought about remarkable regeneration of periodontal tissues, whereas periodontal regeneration was rare in the HA/TCP group. Conclusions: Allogeneic SPDs can effectively repair hard and soft tissue loss brought about by periodontitis in a swine model. Allogeneic SHEDs, which are easily accessible, may be applied to treat periodontitis in clinics in the future.     

Dentinogenic Responses after Direct Pulp Capping of Miniature Swine Teeth with Biodentine

Introduction

The aim of this study was to evaluate pulpal responses after experimental direct pulp capping of mechanically exposed teeth with a new calcium silicate–based dentin replacement material.

Methods

Thirty-four anterior and posterior teeth of 3 miniature swine were used. Class V or I cavities were prepared on the buccal or occlusal surfaces, respectively. Pulpal exposures were further performed using a round carbide bur 0.8 mm in diameter. Exposures were treated with white MTA Angelus (Angelus, Londrina, PR, Brazil) or Biodentine (Septodont, Saint Maur des Fosses, France), and the cavities were further restored with Biodentine. The pulpal tissue responses were histologically assessed at postoperative periods of 3 and 8 weeks. Data were statistically analyzed using the Kruskal Wallis and the Mann-Whitney U tests.

Results

Inflammatory infiltration or pulp tissue necrosis was not found in any of the specimens. All teeth showed mineralized matrix formation in the form of a complete hard tissue bridge composed of osteodentin or osteodentin followed by a discontinuous or continuous reparative dentin zone. A significantly higher thickness of the hard tissue bridge was found in the group of teeth treated with Biodentine at both 3 and 8 weeks. A number of teeth, which were under root development at the onset of the experimental procedures, exhibited ectopic pulp calcification.

Conclusions

The application of both calcium silicate–based materials in direct contact with the mechanically exposed pulp of healthy miniature swine teeth led to pulp repair with complete hard tissue bridge formation. The thickness of hard tissue bridges was significantly higher after pulp capping with Biodentine.     

Methicillin-resistant Staphylococcus aureus in food products: cause for concern or case for complacency?

The widespread use of antimicrobial agents, in combination with insufficient infection control measures, is the main driver of the current pandemic of antimicrobial resistance in human pathogens. The use of antimicrobials in food animal production also contributes, because resistant organisms and resistance genes can spread from animals to humans by direct contact or through the food chain. An important, traditionally human, pathogen, methicillin-resistant Staphylococcus aureus (MRSA), is currently endemic in many hospitals around the world and has also emerged in the community. Recently, a new reservoir of MRSA has been identified in food production animals and people in contact with these animals. This involves a specific clone, multilocus sequence type 398 (ST398), which has spread extensively among animals. ST398 has also been found in up to 11.9% of retail meat samples in several surveys from different parts of the world, posing a potential threat to human health.