Intracardiac allogeneic porcine mesenchymal stem cells elicit an immune response despite their low immunogenic profile in vitro. This result suggests that in vivo characteristics of allogeneic MSCs might differ and emphasizes the importance of pursuing research both in vitro and in vivo.
Optimal alginate encapsulation significantly prolonged adult pig islet survival into primates for up to 6 months, even in the presence of antibody response.
The almost uniform failure in transplant patients of tolerance-inducing regimens that have been found to be effective in rodents, has made it necessary to examine large animal models before testing of new approaches clinically. Miniature swine have been shown to share many relevant immunologic parameters with humans, and because of their reproducible genetics, have proved extremely useful in providing such a large animal model. We have previously shown that indefinite systemic tolerance to renal allografts in miniature swine is induced in 100% of cases across a two-haplotype class I plus minor histocompatibility antigen disparity by a 12-d course of Cyclosporine A (CyA), in contrast to irreversible rejection observed uniformly without CyA treatment. In the present study, we have examined the role of the thymus during the induction of tolerance by performing a complete thymectomy 21 d before renal transplantation. This analysis demonstrated a striking difference between thymectomized and nonthymectomized animals. Thymectomized swine developed acute cellular rejection characterized by a T cell (CD25+) infiltrate, tubulitis, endothelialitis and glomerulitis, and anti–donor CTL reactivity in vitro. Nonthymectomized and sham thymectomized animals had a mild T cell infiltrate with few CD25+ cells and no anti–donor CTL response in vitro. These results indicate that the thymus is required for rapid and stable induction of tolerance.
Both methods reduced the level of anti-pig IgM and IgG xenoreactive antibodies to nearly background, but column perfusion caused less hypotension and reduction in platelets than liver perfusion. Four pig kidneys transplanted into monkeys after column perfusion did not undergo hyperacute rejection, remaining functional for 2-10 days, with a mean functional period of 7 days, demonstrating that a pig kidney can support renal function in a primate.
This prospective clinical study suggests that elective laparoscopic surgery for hematological diseases does not allow complete detection of accessory spleens. Moreover, after such a laparoscopic approach, residual splenic tissue is detectable in half of the patients during the follow-up.
The aim of this study was to assess the importance of deconvolution for the calculation of renal perfusion and glomerular filtration rate (GFR) on the basis of concentration-time curves as measured with perfusion MRI. Six rabbits were scanned dynamically after injection of a gadolinium chelate. Concentration-time curves were generated by manually drawing regions of interest in the aorta and the renal cortex. To remove the dependency on the arterial input function, a regularized structured total least-squares deconvolution algorithm was used to calculate the renal impulse response. This curve was fitted by the sum of two gamma variate functions, corresponding to the passage of the contrast agent in the glomeruli and the proximal convoluted tubules. Tracer kinetics models were applied to these two functions to obtain the renal perfusion and GFR.
The VAJ is not planar; it is above the level of the BR from the left/right to the right/non commissure. As a consequence, the external height of the non/left commissure is greater than the other 2 commissures. These findings should be taken into consideration when performing aortic valve-sparing reimplantation or external annuloplasty.
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