Impaired lymphocyte transformation response to cytomegalovirus and phytohemagglutinin in recipients of renal transplants: association with antithymocyte globulin

Cell-mediated immunity was assessed in 38 seropositive recipients of renal transplants by measuring the in vitro lymphocyte transformation response (LTR) to cytomegalovirus (CMV) and to phytohemagglutinin; results were correlated with clinical course, viral excretion, and immunosuppressive treatment. Thirteen seropositive controls all responded to CMV with a mean stimulation index of 31 +/- 6; 14 seronegative controls all had stimulation indices of less than 3. LTR to CMV was found to require both thymus-derived lymphocytes and macrophages. Before immunosuppression, responses of patients were similar to those of controls. After renal transplantation mean LTRs to CMV were dramatically reduced up to 18 months postoperatively, especially in patients treated with antithymocyte globulin. Viremia and CMV-related illness were significantly more frequent in recipients of antithymocyte globulin. Although there was only a rough correlation between clinical events and LTR to CMV, five deaths were noted among seven patients (all treated with antithymocyte globulin) who failed to respond to phytohemagglutinin on two consecutive tests.     

Ammonia binding to the oxygen-evolving complex of photosystem II identifies the solvent-exchangeable oxygen bridge (μ-oxo) of the manganese tetramer

The assignment of the two substrate water sites of the tetra-manganese penta-oxygen calcium (Mn₄O₅Ca) cluster of photosystem II is essential for the elucidation of the mechanism of biological O-O bond formation and the subsequent design of bio-inspired water-splitting catalysts. We recently demonstrated using pulsed EPR spectroscopy that one of the five oxygen bridges (μ-oxo) exchanges unusually rapidly with bulk water and is thus a likely candidate for one of the substrates. Ammonia, a water analog, was previously shown to bind to the Mn₄O₅Ca cluster, potentially displacing a water/substrate ligand [Britt RD, et al. (1989) J Am Chem Soc 111(10):3522–3532]. Here we show by a combination of EPR and time-resolved membrane inlet mass spectrometry that the binding of ammonia perturbs the exchangeable μ-oxo bridge without drastically altering the binding/exchange kinetics of the two substrates. In combination with broken-symmetry density functional theory, our results show that (i) the exchangable μ-oxo bridge is O5 {using the labeling of the current crystal structure [Umena Y, et al. (2011) Nature 473(7345):55–60]}; (ii) ammonia displaces a water ligand to the outer manganese (Mn_A4-W1); and (iii) as W1 is trans to O5, ammonia binding elongates the Mn_A4-O5 bond, leading to the perturbation of the μ-oxo bridge resonance and to a small change in the water exchange rates. These experimental results support O-O bond formation between O5 and possibly an oxyl radical as proposed by Siegbahn and exclude W1 as the second substrate water.     

Polymers with antimicrobial groups--synthesis and activity

Polymers with Antimicrobial Groups – Synthesis and Activity The synthesis of insoluble polymers with covalently bonded antimicrobial groups is described. Their activities against Staphylococcus aureus were investigated.     

Angiographic anatomy of hearts with one ventricular chamber: the true single ventricle

Fifteen patients with an isolated ventricular chamber were studied using angiography. These patients constitute 7% of the 218 patients with single ventricle who were examined at our institution over a 10-year period. The atrial situs was solitus in 6 and isomeric in 9. The ventricular chamber showed 3 varieties based on trabecular pattern: right type, mixed and indeterminate. The atrioventricular (AV) connection was through 2 valves in 4 hearts, through a common AV valve in 8 and through a single valve in 3. The morphologic features of the ventricular chamber and the AV valves are considered the most important factors for planning surgical management.     

Kidney transplantation in patients with end stage congenital renal disease: Report of eighteen cases and review of the organ transplant registry

Eighteen patients with end stage congenital renal disease requiring kidney transplantation constituted 12 per cent of the transplantation recipients at this institution over the past six years. The post-transplantation course in this group was remarkably satisfactory, with a 94 per cent graft survival at three years. In addition, we analyzed survival data from over 9,900 patients in the Organ Transplant Registry and demonstrated that transplant recipients with end stage congenital renal disease have equal or better five year patient survival compared with those with acquired end stage renal disease. Only those patients with adult polycystic disease had a less satisfactory prognosis, probably because of age-related factors. In contrast, there were few statistical correlations between renal allograft survival, age, and original disease.