Influence of renal transplantation and living kidney donation on large artery stiffness and peripheral vascular resistance

BACKGROUND: Vascular status following renal transplantation (RT) may improve while living kidney donation (LKD) is possibly associated with an increased cardiovascular risk. METHODS: We prospectively assessed glomerular filtration rate (mGFR, 51Chrome EDTA clearance) and intermediate vascular risk factors in terms of blood pressure (BP), pulse wave velocity (PWV), central augmentation index (AIx), excess pressure (Pexcess) and forearm vascular resistance in donors (n=58, 45±13 years) and recipients (n=51, 50±12 years) before and one year following LKD or RT. RESULTS: After kidney donation mGFR decreased by 33% to 65±11 ml/min/1.73m2 while recipients obtained a mGFR of 55±9 ml/min/1.73m2. Ambulatory 24-hour mean BP (MAP) remained unchanged in donors but decreased by 5 mmHg in recipients (P<0.05). Carotid-femoral PWV increased by 0.3 m/s in donors (P<0.05) but remained unchanged in recipients. AIx was unaltered after LKD but decreased following RT (P<0.01) while Pexcess did not change in either group. Resting forearm resistance (Rrest), measured by venous occlusion plethysmography, increased after LKD (P<0.05) but was unaffected by RT, while no changes were seen in minimum resistance (Rmin). ΔPWV showed a positive linear association to Δ24-hour MAP in both groups. Multiple linear regression analysis (adjusting for age, gender and the baseline value of the studied parameter) did not detect independent effects of graft function on 24-hour MAP, PWV, AIx, vascular resistance or Pexcess, whereas low post-donation GFR was related to higher AIx and Rrest. CONCLUSIONS: RT reduced BP and AIx without affecting PWV whereas LKD resulted in increased PVW and Rrest, despite unchanged BP

A Formalism for Scattering of Complex Composite Structures. 1 Applications to Branched Structures of Asymmetric Sub-Units

We present a formalism for the scattering of an arbitrary linear or acyclic branched structure build by joining mutually non-interacting arbitrary functional sub-units. The formalism consists of three equations expressing the structural scattering in terms of three equations expressing the sub-unit scattering. The structural scattering expressions allows a composite structures to be used as sub-units within the formalism itself. This allows the scattering expressions for complex hierarchical structures to be derived with great ease. The formalism is furthermore generic in the sense that the scattering due to structural connectivity is completely decoupled from internal structure of the sub-units. This allows sub-units to be replaced by more complex structures. We illustrate the physical interpretation of the formalism diagrammatically. By applying a self-consistency requirement we derive the pair distributions of an ideal flexible polymer sub-unit. We illustrate the formalism by deriving generic scattering expressions for branched structures such as stars, pom-poms, bottle-brushes, and dendrimers build out of asymmetric two-functional sub-units.Comment: Complete rewrite generalizing the formalism to arbitrary functional sub-units and including a new Feynmann like diagrammatic interpretatio