Search

Induced oral tolerance to mucosal-exposed antigens in immunized animals is of particular interest for the development of immunotherapeutic approaches to human allergic diseases. This is a unique feature of mucosal surfaces which represent the main contact interface with the external environment. However, the influence of oral tolerance on specific and natural polyreactive IgA antibodies, the major defense mechanism of the mucosa, is unknown. We have shown that oral administration of an extract of the dust mite Dermatophagoides pteronyssinus (Dp) to primed mice caused down-regulation of IgE responses and an increase in tumor growth factor-ß secretion. In the present study, we observed that primed inbred female A/Sn mice (8 to 10 weeks old) fed by gavage a total weight of 1.0-mg Dp extract on the 6th, 7th and 8th days post-immunization presented normal secretion of IL-4 and IL-10 in gut-associated lymphoid tissue and a decreased production of interferon gamma induced by Dp in the draining lymph nodes (13,340 ± 3,519 vs 29,280 ± 2,971 pg/ml). Mice fed the Dp extract also showed higher levels of serum anti-Dp IgA antibodies and an increase of IgA-secreting cells in mesenteric lymph nodes (N = 10), reflecting an increase in total fecal IgA antibodies (N = 10). The levels of secretory anti-Dp IgA antibodies increased after re-immunization regardless of Dp extract feeding. Oral tolerance did not interfere with serum or secretory IgA antibody reactivity related to self and non-self antigens. These results suggest that induction of oral tolerance to a Dp extract in sensitized mice triggered different regulatory mechanisms which inhibited the IgE response and stimulated systemic and secretory IgA responses, preserving the natural polyreactive IgA antibody production.

This paper presents the performance evaluation of an amplify-and-forward (AF) relay-assisted multiuser multiple input-multiple output (MU-MIMO) downlink transmission system for correlated fading channels. The overall system performance was improved by incorporating a double-quadrature spatial modulation (DQSM) scheme. The bit error rate (BER) performance and detection complexity of the AF-MU-MIMO-DQSM system were analyzed and com-pared with those of a conventional AF-MU-MIMO system under the same conditions and parameters. The results showed that the correlated fading channel severely affected the performance of systems with higher spectral efficiency (SE). Considering an SE of 12 bpcu/user, the AF-MU-MIMO-DQSM system yielded a gain of up to 3 dB in BER performance compared with that of its conventional counterpart for the analyzed cases. In terms of detection com-plexity, the AF-MU-MIMO-DQSM system showed a reduction of up to 56 % compared with that of the conventional system for the optimal maximum likelihood detection criterion.

This paper proposes a Simplified Finite-Set Model Predictive Power Controller (MPPC) to improve the performance of the Doubly-Fed Induction Generator (DFIG). The MPPC is implemented to regulate the stator active and reactive powers of DFIG, minimizing the error between them and their references, with an optimized null vector selection and a reduced number of active vectors, to decrease the computational burden. This reduction is applied in a two-level converter, reducing the test to 4 or 2 active vectors. Simulations and laboratory experiments were performed, showing results for a 0.56 kW DFIG. Finally, it was verified that the proposed system can maintain the stator powers at a reference.

Angiotensin-(1–7) is a peptide produced by different pathways, and regardless of the route, the angiotensin-converting enzyme 2 (ACE-2) is involved in one of the steps of its synthesis. Angiotensin-(1–7) binds to Mas receptors localized in different cells throughout the body. Whether angiotensin-(1–7) exerts any action in the urinary bladder (UB) is still unknown. We investigated the effects of intravenous and topical (in situ) administration of angiotensin-(1–7) on intravesical pressure (IP) and cardiovascular variables. In addition, the Mas receptors and ACE-2 gene and protein expression were analyzed in the UB. Adult female Wistar rats were anesthetized with 2% isoflurane in 100% O2 and submitted to the catheterization of the femoral artery and vein for mean arterial pressure (MAP) and heart rate (HR) recordings, and infusion of drugs, respectively. The renal blood flow was acquired using a Doppler flow probe placed around the left renal artery and the renal conductance (RC) was calculated as a ratio of Doppler shift (kHz) and MAP. The cannulation of the UB was performed for IP recording. We observed that angiotensin-(1–7) either administered intravenously [115.8 ± 28.6% angiotensin-(1–7) vs. −2.9 ± 1.3% saline] or topically [147.4 ± 18.9% angiotensin-(1–7) vs. 3.2 ± 2.8% saline] onto the UB evoked a significant (p < 0.05) increase in IP compared to saline and yielded no changes in MAP, HR, and RC. The marked response of angiotensin-(1–7) on the UB was also investigated using quantitative real-time polymerase chain reaction and western blotting assay, which demonstrated the mRNA and protein expression of Mas receptors in the bladder, respectively. ACE-2 mRNA and protein expression was also observed in the bladder. Therefore, the findings demonstrate that angiotensin-(1–7) acts in the UB to increase the IP and suggest that this peptide can be also locally synthesized in the UB.

ABSTRACT: Periodontal disease is the most common infectious disease that occurs in feline patients. Although it occurs in both sexes, different age groups, and any breeds, the prevalence and severity seem much higher in cats living in animal shelters. This paper aimed to describe the clinical, radiological, cytopathological, and virological aspects of periodontal disease and its complications in cats, based on these aspects and, consequently, on the importance it brings to cat feline medicine in shelter cats. For this, nine cats with periodontal disease from a single animal shelter were evaluated. These cats demonstrated a disease characterized by halitosis, excessive salivation, and oral discomfort. Lymphadenomegaly of the mandibular and retropharyngeal lymph nodes was observed in 44.4% of the cases. Oral lesions consisted of varying degrees of gingival hyperemia, complete loss of free gingival margins, and consequently gingival retraction, dental calculus deposition, dental mobility, complete exposure of the furcation of premolars and molars, and dental roots of canines and incisors, loss of bone radiopacity due to alveolar bone resorption and tooth loss. Complications included chronic ulcerative paradental stomatitis (22.2%), faucitis (22.2%), and chronic gingivostomatitis (11.1%). None of the cats affected by periodontal disease was positive for FIV or FeLV. In 33.3% of the cases, cats were carriers of feline calicivirus, but not feline herpesvirus.