Robotic-assisted laparoscopic partial nephrectomy for a 7-cm mass in a renal allograft

Treatment options for a suspicious renal mass in a renal allograft include radical nephrectomy or nephron-sparing surgery (NSS). To our knowledge robotic-assisted laparoscopic partial nephrectomy (RPN) as treatment for a renal mass in a transplant kidney has not been previously reported. We report the case of RPN for a 7-cm renal mass in a transplanted kidney. A 35-year-old female with reflux nephropathy received a living-related donor kidney transplant in 1986. At 24 years after transplantation she had a 7-cm Bosniak III cystic mass of the allograft detected on computerized tomography (CT) scan. Preoperative creatinine was 2.2 mg/dL with an estimated glomerular filtration rate (eGFR) of 25 mL/min/1.73 m(2) . RPN was performed with bulldog clamping of the renal vessels, the graft was left in situ and immunosuppression was maintained postoperatively. Tumor diameter was 7.3 cm with a nephrometry score of 10a. Warm ischemia time (WIT) was 26.5 min. Estimated blood loss was 100 mL. There was no change between pre- and postoperative eGFR. There were no operative complications. Histology was papillary renal cell carcinoma type 1, nuclear grade 2. Margins were negative. RPN is a technically feasible treatment option for a suspicious renal mass in renal allografts.

Distance measurements in model bis-Gd(III) complexes with flexible "bridge". Emulation of biological molecules having flexible structure with Gd(III) labels attached

In this work, we continue to explore Gd(III) as a possible spin label for high-field Double Electron-Electron Resonance (DEER) based distance measurements in biological molecules with flexible geometry. For this purpose, a bis-Gd(III) complex with a flexible "bridge" was used as a model. The distances in the model were expected to be distributed in the range of 5-26 A, allowing us to probe the shortest limits of accessible distances which were found to be as small as 13 A. The upper distance limit for these labels was also evaluated and was found to be about 60 A. Various pulse duration setups can result in apparent differences in the distribution function derived from DEER kinetics due to short distance limit variations. The advantages, such as the ability to perform measurements at cryogenic temperatures and high repetition rates simultaneously, the use of very short pumping and observation pulses without mutual interference, the lack of orientational selectivity, as well as the shortcomings, such as the limited mw operational frequency range and intrinsically smaller amplitude of oscillation related to dipolar interaction as compared with nitroxide spin labels are discussed. Most probably the use of nitroxide and Gd-based labels for distance measurements will be complementary depending on the particulars of the problem and the availability of instrumentation.

Ethical considerations for participation of nondirected living donors in kidney exchange programs

Kidneys from nondirected donors (NDDs) have historically been allocated directly to the deceased donor wait list (DDWL). Recently, however, NDDs have participated in kidney exchange (KE) procedures, including KE 'chains', which have received considerable media attention. This increasing application of KE chains with NDD participation has occurred with limited ethical analysis and without ethical guidelines. This article aims to provide a rigorous ethical evaluation of NDDs and chain KEs. NDDs and bridge donors (BDs) (i.e. living donors who link KE procedures within KE chains) raise several ethical concerns including coercion, privacy, confidentiality, exploitation and commercialization. In addition, although NDD participation in KE procedures may increase transplant numbers, it may also reduce NDD kidney allocation to the DDWL, and disadvantage vulnerable populations, particularly O blood group candidates. Open KE chains (also termed 'never-ending' chains) result in a permanent diversion of NDD kidneys from the DDWL. The concept of limited KE chains is discussed as an ethically preferable means for protecting NDDs and BDs from coercion and minimizing 'backing out', whereas 'honor systems' are rejected because they are coercive and override autonomy. Recent occurrences of BDs backing out argue for adoption of ethically based protective measures for NDD participation in KE.

Patterns of Renal Function in Hypertension Due to Unilateral Renal Artery Occlusion

We performed renal function studies in dogs with chronic renovascular hypertension produced by complete occlusion of a renal artery. In addition, we evaluated in anesthetized dogs the acute effects of a novel angiotensin converting enzyme inhibitor, CGS 16,617, on renal function and plasma neurohormones (epinephrine, norepinephrine and vasopressin) 4 weeks after initiation of 2 kidney, 1 clip hypertension. CGS 16,617 effectively decreased blood pressure in renal hypertensive animals. This response was associated with suppression of angiotensin II indicating effective converting enzyme inhibition. In the non-clipped kidney, acute administration of CGS 16,617 increased effective renal plasma flow but not glomerular filtration rate and urinary sodium excretion. In the clipped kidney, CGS 16,617 caused no change in any parameter of renal function. Plasma norepinephrine, epinephrine and vasopressin were unaffected by administration of CGS 16,617. These studies showed that chronic occlusion of a renal artery does not result in renal infarction because of a compensatory increase in the amount of blood provided through capsular collateral vessels. The collateral circulation which has developed in the clipped kidney explains the lack of a converting enzyme inhibitor effect.

Ligand protons in a frozen solution of copper histidine relax via a T1e -driven three-spin mechanism

Davies electron-nuclear double resonance spectra can exhibit strong asymmetries for long mixing times, short repetition times, and large thermal polarizations. These asymmetries can be used to determine nuclear relaxation rates in paramagnetic systems. Measurements of frozen solutions of copper(L-histidine)(2) reveal a strong field dependence of the relaxation rates of the protons in the histidine ligand, increasing from low (g( parallel)) to high (g( perpendicular)) field. It is shown that this can be attributed to a concentration-dependent T(1e)-driven relaxation process involving strongly mixed states of three spins: the histidine proton, the Cu(II) electron spin of the same complex, and another distant electron spin with a resonance frequency differing from the spectrometer frequency approximately by the proton Larmor frequency. The protons relax more efficiently in the g( perpendicular) region, since the number of distant electrons able to participate in this relaxation mechanism is higher than in the g( parallel) region. Analytical expressions for the associated nuclear polarization decay rate Tau(een) (-1) are developed and Monte Carlo simulations are carried out, reproducing both the field and the concentration dependences of the nuclear relaxation.

Donor kidney volume and outcomes following live donor kidney transplantation

Pre-donation kidney volume and function may be crucial factors in determining graft outcomes in kidney transplant recipients. We measured living donor kidney volumes by 3D helical computed tomography scanning and glomerular filtration rate (GFR) by (125)I-iothalamate clearances in 119 donors, and correlated these values with graft function and incidence of acute rejection at 2 years post-transplantation. Kidney volume strongly correlated with GFR (Pearson r= 0.71, p < 0.001). Body size and male gender were independent correlates of larger kidney volumes, and body size and age were predictors of kidney function. The effects of transplanted kidney volume on graft outcome were studied in 104 donor-recipient pairs. A transplanted kidney volume greater than 120 cc/1.73 m(2) was independently associated with better estimated GFR at 2 years post-transplant when compared to recipients of lower transplanted kidney volumes (64 +/- 19 vs. 48 +/- 14 mL/min/1.73 m(2), p < 0.001). Moreover, recipients of lower volumes had a higher incidence of acute cellular rejection (16% vs. 3.7%, p = 0.046). In conclusion, kidney volume strongly correlates with function in living kidney donors and is an independent determinant of post-transplant graft outcome. The findings suggest that (1) transplantation of larger kidneys confers an outcome advantage and (2) larger kidneys should be preferred when selecting from otherwise similar living donors.

Morphological transitions during the formation of templated mesoporous materials: theoretical modeling

We put forward a theoretical model for the morphological transitions of templated mesoporous materials. These materials consist of a mixture of surfactant molecules and inorganic compounds which evolve dynamically upon mixing to form different morphologies depending on the composition and conditions at which mixing occurs. Our theoretical analysis is based on the assumption that adsorption of the inorganic compounds onto mesoscopic assemblies of surfactant molecules changes the effective interactions between the surfactant molecules, consequently lowering the spontaneous curvature of the surfactant layer and inducing morphological changes in the system. On the basis of a mean field phase diagram, we are able to follow the trajectories of the system starting with different initial conditions, and predict the final morphology of the product. In a typical scenario, the reduction in the spontaneous curvature leads first to a smooth transition from compact spherical micelles to elongated worm-like micelles. In the second stage, the layer of inorganic material coating the micelles gives rise to attractive inter-micellar interactions that eventually induce a collapse of the system into a closely packed hexagonal array of coated cylinders. Other pathways may lead to different structures including disordered bicontinuous and ordered cubic phases. The model is in good qualitative agreement with experimental observations.

Alemtuzumab induction and sirolimus plus mycophenolate mofetil maintenance for CNI and steroid-free kidney transplant immunosuppression

We performed a pilot study in which 22 kidney recipients (14 LD: 8 DCD) were given alemtuzumab induction (30 mg day 0 and 1), steroids (500 mg mp day 0 and 1, none thereafter), mycophenolate mofetil (MMF) maintenance (500 mg b.i.d) and sirolimus (concentration controlled 8-12 ng/mL). With a mean follow-up of 15.9 months, patient survival is (21/22) 96% and graft survival (19/22) 87%. Acute rejections occurred in (8) 36.3% (two humoral). Of 19 surviving grafts, 18 (95%) remain steroid and 15 (79%) CNI-free. At 1 year, mean creatinine was 1.43 mg/dL. Overall infection rates were low, but 2 patients developed severe acute respiratory distress syndrome (ARDS) at month 3 and 7, respectively, resulting in mortality in one and a graft loss in the other. No cancer or PTLD was observed. Leukopenia was common and MMF dose was reduced or eliminated in 6/22 (27%) patients. The reported higher than expected rate of acute rejection, leukopenia and possible pulmonary toxicity suggests excessive morbidity. Modifications such as an initial period of CNI use should be considered.

Spin Distribution and the Location of Protons in Paramagnetic Proteins

▪ Abstract  Two current frontiers in EPR research are high-field ([Formula: see text]) electron paramagnetic resonance (EPR) and high-field electron-nuclear double resonance (ENDOR). This review focuses on recent advances in high-field ENDOR and its applications to the study of proteins containing native paramagnetic sites. It concentrates on two aspects; the first concerns the determination of the location of protons and is related to the site geometry, and the second focuses on the spin density distribution within the site, which is inherent to the electronic structure. Both spin density and proton locations can be derived from ligand hyperfine couplings determined by ENDOR measurements. A brief description of the experimental methods is presented along with a discussion of the advantages and disadvantages of high-field ENDOR compared with conventional X-band (∼ 9.5 GHz) experiments. Specific examples of both protein single crystals and frozen solutions are then presented. These include the determination of the coordinates of water ligand protons in the Mn(II) site of concanavalin A, the detection of hydrogen bonds in a quinone radical in the bacterial photosynthetic reaction center as well as in the tyrosyl radical in ribonuclease reductase, and the study of the spin distribution in copper proteins. The copper proteins discussed are the type I copper of azurin and the binuclear CuA center in a number of proteins. The last part of the review presents a brief discussion of the interpretation of hyperfine couplings using quantum chemical calculations, primarily density functional theory (DFT) methods. Such methods are becoming an integral part of the data analysis tools, as they can facilitate signal assignment and provide the ultimate relation between the experimental hyperfine couplings and the electronic wave function.

2D TRIPLE in orientationally disordered samples--a means to resolve and determine relative orientation of hyperfine tensors

The two-dimensional (2D) TRIPLE experiment provides correlations between electron-nuclear double resonance (ENDOR) frequencies that belong to the same electron-spin manifold, M(S), and therefore allows to assign ENDOR lines to their specific paramagnetic centers and M(S) manifolds. This, in turn, also provides the relative signs of the hyperfine couplings. So far this experiment has been applied only to single crystals, where the cross-peaks in the 2D spectrum are well resolved with regular shapes. Here we introduce the application of the 2D TRIPLE experiment to orientationally disordered systems, where it can resolve overlapping powder patterns. Moreover, analysis of the shape of the cross-peaks shows that it is highly dependent on the relative orientation of the hyperfine tensors of the two nuclei contributing to this particular peak. This is done initially through a series of simulations and then demonstrated experimentally at a high field (W-band, 95 GHz). The first example concerned the (1)H hyperfine tensors of the stable radical alpha,gamma-bisdiphenylene-beta-phenylallyl (BDPA) immobilized in a polystyrene matrix. Then, the experiment was applied to a more complex system, a frozen solution of Cu(II)-bis(2,2':6',2'' terpyridine) complex. There, the 2D TRIPLE experiment was combined with the variable mixing time (VMT) ENDOR experiment, which determined the absolute sign of the hyperfine couplings involved, and orientation selective ENDOR experiments. Analysis of the three experiments gave the hyperfine tensors of a few coupled protons.

New Synthesis and Insight into the Structure of Blue Ultramarine Pigments

A new and easy method for preparing blue sodalite pigments which involves high-temperature calcination of sodalite samples synthesized with aluminum sulfate and an organic template, is presented. Calcination generated the S(3)(-) and S(2)(-) radicals, and the effects of the Al/Si ratio and the calcination temperature on the nature and amounts of the radicals were examined. The radicals were characterized in detail by continuous wave and pulsed EPR at X- and W-band frequencies (approximately 9 and 95 GHz, respectively) complemented by UV-vis measurements. The high-field electron-paramagnetic resonance (EPR) measurements allowed us to clearly resolve the g anisotropy of S(3)(-) and W-band electron nuclear double resonance (ENDOR) measurements detected strong coupling with extra-framework (23)Na cations and weak coupling with framework (27)Al. On the basis of the spectroscopic results and density functional theory (DFT) calculations of the g-tensors of S(3)(-) and S(2)(-) radicals, the EPR signals were attributed to three different radicals, all with the open structure C(2v), that are located within the sodalite beta cages. While two of these radicals are well isolated, the third one is associated with an exchange-narrowed signal originating from S(3)(-) radicals in nearby sodalite cages.

Pathways for the nuclear transport of proteins and RNAs

The nuclear pore complex catalyses the import and export of both proteins and RNAs. The molecular mechanisms of RNA and protein translocation through the nuclear pore are likely to be similar; however, their signals and targeting apparatus may differ. Recent insights into RNA transport have come from studies of kinetic control mechanisms and the preconditions for translocation that include processing, RNP assembly, and a targeting function for 5' caps.

Improving W-band pulsed ENDOR sensitivity--random acquisition and pulsed special TRIPLE

Two approaches for improving the signal-to-noise ratio (S/N) of W-band pulsed electron-nuclear double resonance (ENDOR) spectra are presented. One eliminates base-line problems while the other enhances the ENDOR effect. High field ENDOR spectra measured at low temperatures often suffer from highly distorted base-lines due to the heating effect of the RF pulses that causes some detuning of the cavity and therefore leads to a reduction in the echo intensity. This is a severe problem because it often masks broad and weak ENDOR signals. We show that it can be eliminated by recording the ENDOR spectrum in a random, rather than the standard sequential variation of the RF frequency. The S/N of the ENDOR spectrum can be significantly enhanced by the application of the pulse analog of the continuous wave (CW) special TRIPLE experiment. While this experiment is not applicable in the solid state at conventional X-band frequencies, at W-band it is most efficient. We demonstrate the efficiency of the special TRIPLE Davies and Mims experiments on single crystals and orientationally disordered systems.