Production of Feline Universal Erythrocytes with Methoxy Polyethylene Glycol.

Blood group mismatch in veterinary medicine is a significant problem in blood transfusion, sometimes leading to severe transfusion reactions and even patient death. Blood groups vary from species to species and there are three known blood groups in cats: A, B and AB. While A-type cats are most common, there is a shortage of feline B-type blood groups in cats. By using methoxy polyethylene glycol (mPEG) to protect antigenic epitopes on red blood cells (RBCs), we aimed to find the optimal conditions for the production of feline universal RBCs. The surfaces of feline A-type RBCs were treated with mPEG at various molecular weights and concentrations. Agglutination tests showed that the coating of feline A-type RBCs with mPEG of 20 kDa and 2 mM blocked hemagglutination to feline anti-A alloantibodies over 8 h. While no differences in RBC size and shape between intact and mPEG-treated RBCs were seen, coating RBCs with mPEG inhibited the binding of feline anti-A alloantibodies. Furthermore, the mPEG-treated RBCs did not cause spontaneous hemolysis or osmotic fragility, compared to control RBCs. According to a monocyte monolayer assay, mPEG treatment significantly reduced feline anti-A antibody-mediated phagocystosis of RBCs. These results confirm the potential of using activated mPEG on feline A-type RBC to create universal erythrocytes for transfusion to B-type cats.

Effect of PRX-1 Downregulation in the Type 1 Diabetes Microenvironment.

Type 1 diabetes (T1D) is caused by dysregulation of the immune system in the pancreatic islets, which eventually leads to insulin-producing pancreatic ß-cell death and destabilization of glucose homeostasis. One of the major characteristics of T1D pathogenesis is the production of inflammatory mediators by macrophages that result in destruction or damage of pancreatic ß-cells. In this study the inflammatory microenvironment of T1D was simulated with RAW264.7 cells and MIN6 cells, acting as macrophages and pancreatic ß-cells respectably. In this setting, peroxiredoxin-1, an anti-oxidant enzyme was knocked down to observe its functions in the pathogenesis of T1D. RAW264.7 cells were primed with lipopolysaccharide and co-cultured with MIN6 cells while PRX-1 was knocked down in one or both cell types. Our results suggest that hindrance of PRX-1 activity or the deficiency of this enzyme in inflammatory conditions negatively affects pancreatic ß-cell survival. The observed decrease in viability of MIN6 cells seems to be caused by nitric oxide production. Additionally, it seems that PRX-1 affects previously reported protective activity of IL-6 in pancreatic ß cells as well. These results signify new, undiscovered roles for PRX-1 in inflammatory conditions and may contribute toward our understanding of autoimmunity.

CTLA-4-Tg/CD-28-KO Mice Exhibit Reduced T Cell Proliferation in vivo Compared to CD-28-KO Mice in a Graft-versus-host Disease Model.

Activated T cells express inhibitory receptors such as CTLA-4 that can downregulate immune responses. Blockade of or genetic deficiency in CTLA-4 can result in autoimmunity. Therefore, strategies to increase the inhibitory function of CTLA-4 may be attractive in settings of undesirable T cell responses such as autoimmunity or transplant rejection. We have tested the hypothesis that transgenic constitutive expression of CTLA-4 can further attenuate immune responses when compared with normal inducible expression. Our results indicate that transgenic expression of CTLA-4 in mouse T cells (CTLA-4-Tg T cells) results in reduced cell cycle progression and increased apoptosis of TCR-stimulated T cells. CTLA-4-Tg T cells display reduced T cell proliferation in an in vivo model of graft versus host disease (GVHD). These results further our understanding of how CTLA-4 can be manipulated to inhibit immune responses and may help development of new therapeutic strategies for clinical settings of autoimmunity and transplantation.

Clinical characteristics of multiple primary colorectal cancers.

PURPOSE: Although multiple primary colorectal cancer has been recognized as a significant clinical entity, its clinical and pathological features and its prognosis are still controversial. The purpose of this study was to clarify clinical and pathological features of multiple primary colorectal cancer. MATERIALS AND METHODS: Among 1669 patients who underwent surgery for primary colorectal cancer from January 1997 to June 2005, 26 patients (1.6%) with multiple primary colorectal cancer were identified. We reviewed clinical characteristics including diagnostic interval, lesions, operating methods, and TNM stage, and we defined the index lesion as the most advanced lesion among the synchronous lesions. For the purposes of the study, the colon and rectum were classified into three segments. The right-side colon included the appendix, cecum, ascending colon, hepatic flexure, and transverse colon, and the left-side colon included the splenic flexure, descending colon, and sigmoid colon. RESULTS: Of the 26 patients with multiple primary colorectal cancers, nineteen patients were male and seven patients were female, with a mean age of 61.5 years. Nineteen patients had synchronous colorectal cancers and seven patients had metachronous colorectal cancers. In the metachronous cases, the mean diagnostic interval was 36.8 months. The site of the first lesion in metachronous colorectal cancers was the right colon in five cases (71.4%) and the left colon in two cases (28.6%), and the site of the second lesion was the rectum in six cases (55.5%), the right colon in three cases (33.3%), and the left colon in one case. The TNM stage of the second lesions in the metachronous colorectal cancers was stage II in four cases (57.1%), stage III in one case (14.3%), and stage IV in one case (14.3%). For the synchronous colorectal cancers, the operation methods were single-segment resection combined with endoscopic mucosal resection in five cases (26.3%), single-segment resection alone in six cases, two-segment resection in six cases, and total colectomy in two cases. CONCLUSION: In metachronous colorectal cancers, the secondary lesions were later-stage cancer. Therefore, careful postoperative follow-up is necessary for patients who have undergone surgery for colorectal cancers. Further study of therapeutic modalities is important for synchronous colorectal cancers.