Electrical stimulation as a conditioning strategy for promoting and accelerating peripheral nerve regeneration.

The delivery of a nerve insult (a "conditioning lesion") prior to a subsequent test lesion increases the number of regenerating axons and accelerates the speed of regeneration from the test site. A major barrier to clinical translation is the lack of an ethically acceptable and clinically feasible method of conditioning that does not further damage the nerve. Conditioning electrical stimulation (CES), a non-injurious intervention, has previously been shown to improve neurite outgrowth in vitro. In this study, we examined whether CES upregulates regeneration-associated gene (RAG) expression and promotes nerve regeneration in vivo, similar to a traditional nerve crush conditioning lesion (CCL). Adult rats were divided into four cohorts based on conditioning treatment to the common peroneal (fibular) nerve: i) CES (1h, 20Hz); ii) CCL (10s crush); iii) sham CES (1h, 0Hz); or iv) naïve (unconditioned). Immunofluorescence and qRT-PCR revealed significant RAG upregulation in the dorsal root ganglia of both CES and CCL animals, evident at 3-14days post-conditioning. To mimic a clinical microsurgical nerve repair, all cohorts underwent a common peroneal nerve cut and coaptation one week following conditioning. Both CES and CCL animals increased the length of nerve regeneration (3.8-fold) as well as the total number of regenerating axons (2.2-fold), compared to the sham and naïve-conditioned animals (p<0.001). These data support CES as a non-injurious conditioning paradigm that is comparable to a traditional CCL and is therefore a novel means to potentially enhance peripheral nerve repair in the clinical setting.

Design and performance of a large lumen glaucoma drainage device.

PurposeWe report the in vivo testing of a large-lumen glaucoma drainage (LL-GDD) device equipped with a flow regulator. The device's membrane can be non-invasively opened with laser in the postoperative period to adjust aqueous flow and intraocular pressure.MethodsThe initial LL-GDD prototypes were constructed using 22 G silicone angiocatheters cut down to size. A 10 nm PVDF membrane was then affixed to the end using cyanoacrylate. The LL-GDD was tested first in a model eye equipped with ports for infusion and pressure measurement and in New Zealand rabbits.ResultsNew Zealand white satin cross rabbits were used, two eyes receiving the LL-GDD and the two fellow eyes serving as the control group with no intervention performed. After the procedure, the IOP in the LL-GGD surgical group dropped an average of 5.5 mm Hg (P=0.001), which was maintained until the membrane laser procedure at week 5 resulting in an average IOP reduction of 1.8 mm Hg. At week 7, the average IOP in the surgical group was 11 mm Hg compared with 18 mm Hg in the control group (P<0.001). A second laser procedure was done to completely open the membrane face, which resulted in an immediate drop in the average IOP of the surgical group by another 2.7 mm Hg, which was maintained until the study termination at day 55.ConclusionsThe large-lumen glaucoma drainage device demonstrated an ability both to prevent immediate postoperative hypotony and to allow progressively lower IOP on demand in this proof-of-concept study.

Guidelines for the diagnosis of antibody-mediated rejection in pancreas allografts-updated Banff grading schema.

The first Banff proposal for the diagnosis of pancreas rejection (Am J Transplant 2008; 8: 237) dealt primarily with the diagnosis of acute T-cell-mediated rejection (ACMR), while only tentatively addressing issues pertaining to antibody-mediated rejection (AMR). This document presents comprehensive guidelines for the diagnosis of AMR, first proposed at the 10th Banff Conference on Allograft Pathology and refined by a broad-based multidisciplinary panel. Pancreatic AMR is best identified by a combination of serological and immunohistopathological findings consisting of (i) identification of circulating donor-specific antibodies, and histopathological data including (ii) morphological evidence of microvascular tissue injury and (iii) C4d staining in interacinar capillaries. Acute AMR is diagnosed conclusively if these three elements are present, whereas a diagnosis of suspicious for AMR is rendered if only two elements are identified. The identification of only one diagnostic element is not sufficient for the diagnosis of AMR but should prompt heightened clinical vigilance. AMR and ACMR may coexist, and should be recognized and graded independently. This proposal is based on our current knowledge of the pathogenesis of pancreas rejection and currently available tools for diagnosis. A systematized clinicopathological approach to AMR is essential for the development and assessment of much needed therapeutic interventions.

Eculizumab for the treatment of de novo thrombotic microangiopathy post simultaneous pancreas-kidney transplantation--a case report.

A 34-year-old female recipient of a simultaneous pancreas-kidney transplant presented 7 days posttransplant with acute renal allograft dysfunction, thrombocytopenia, and microangiopathic hemolytic anemia. Renal biopsy revealed acute antibody-mediated rejection (AMR) and acute thrombotic microangiopathy (TMA). Clinical and laboratory manifestations, which had only partly responded to treatment with daily plasma exchange and intravenous immunoglobulin, resolved rapidly and completely to eculizumab (Soliris, Alexion Pharmaceuticals, Inc., Cheshire, Conn), a complement factor C5 antibody. De novo posttransplant TMA is a rare and serious complication that can lead to graft loss in up to one third of cases. This is the first report of successful treatment of de novo TMA with eculizumab, which has previously shown benefit in recurrent atypical hemolytic uremic syndrome as well as in refractory acute AMR. Targeted complement inhibition offers the promise of a safe and effective therapeutic strategy in de novo TMA, especially in light of recent evidence suggesting that genetic mutations in complement regulatory proteins may predispose transplant recipients to this serious disease.

Treatment of multidrug-resistant cytomegalovirus retinitis with systemically administered leflunomide.

Multiresistant cytomegalovirus (CMV) infection is increasingly recognized in solid organ transplant recipients. Leflunomide is a novel drug with both immunosuppressive and anti-CMV properties. Herein we report a case of a renal transplant recipient treated with leflunomide for multiresistant CMV retinitis, and provide correlation between serum and vitreous levels of leflunomide. She had stabilization of her retinitis and measurable levels of drug in her vitreous fluid and serum. These initial findings suggest that leflunomide may be useful in the treatment of CMV disease, including retinitis in patients after solid organ transplantation.

Antibody-mediated rejection of a pancreas allograft.

The role of antibody-mediated rejection (AMR) in pancreas transplantation is poorly understood. Here, we report on a patient who developed AMR of his pancreas allograft after receiving a simultaneous pancreas-kidney transplant. Pre-operative enhanced cytotoxicity and flow cytometry T-cell crossmatches were negative; B-cell crossmatches were not performed as per institutional protocol. The patient's post-operative course was significant for elevated serum amylase levels and development of hyperglycemia approximately 1 month after transplantation. A pancreatic biopsy at this time showed no cellular infiltrate but strong immunofluorescent staining for C4d in the interacinar capillaries. Analysis of the patient's serum identified donor-specific HLA-DR alloantibodies. He received intravenous immunoglobulin (IVIg), rituximab and plasmapheresis, and his pancreatic function normalized. We conclude that clinically significant AMR can develop in a pancreas allograft and recommend that pancreatic biopsies be assessed for C4d deposition if the patient has risk factors for AMR and/or the pathologic evidence for cell-mediated rejection is underwhelming.

Renal disease in rats with type 2 diabetes is associated with decreased renal nitric oxide production.

AIMS/HYPOTHESIS: In several other models of chronic renal disease, decreases in renal nitric oxide activity and nitric oxide synthase (NOS) protein abundance have been demonstrated. Here, we studied diabetic obese Zucker (ZDF Gmi fa/fa) rats that develop severe hyperglycaemia and renal disease, together with their lean control animals, to determine if renal nitric oxide deficiency also occurs in this model. METHODS: Obese Zucker rats aged 10 to 12 weeks were maintained on Purina 5008 diet until 4, 8, or 11 months of age and compared with similarly maintained, 4- and 11-month-old lean Zucker rats. NOS activity and abundance of endothelial NOS (eNOS) and neuronal NOS (nNOS) were measured on homogenates of kidney cortex. Blood was analysed for glucose, lipids, creatinine, and blood urea nitrogen and kidney tissue was obtained for histology. RESULTS: Obese rats exhibited severe hyperglycaemia from 4 months of age and developed increasing hyperlipidaemia, proteinuria, and decreasing renal function with age compared to lean counterparts. At 4 months cortical NOS activity and nNOS abundance were lower in obese rats than in lean ones. At 11 months NOS activity remained depressed and nNOS abundance had declined further in obese rats. Glomerulosclerosis in the obese rats was mild at 4 months, becoming severe by 11 months. Lean rats had only mild age-dependent increases in glomerular injury. CONCLUSIONS/INTERPRETATION: The chronic renal disease that occurs in hyperglycaemic, obese Zucker rats is associated with decreased renal cortical nitric oxide production and increasing renal injury, although the changes do not resemble those of diabetic nephropathy in man.

Association of angiotensin-converting enzyme polymorphisms with systemic lupus erythematosus and nephritis: analysis of 644 SLE families.

Angiotensin II is a strong candidate for the perpetuation of autoimmunity, nephritis and visceral damage in systemic lupus erythematosus (SLE). Our goal was to determine whether angiotensin-converting enzyme (ACE) gene polymorphisms are associated with SLE and/or lupus nephritis (LN). We genotyped 644 SLE patients and 1130 family members for three ACE gene polymorphisms: Alu insertion/deletion (I/D), 23949 (CT)(2/3) and 10698 (G)(3/4). All patients met the American College of Rheumatology (ACR) criteria for SLE, and all LN patients met ACR renal criteria and/or had biopsy evidence of LN. We used the transmission/disequilibrium test (TDT) to examine associations between each polymorphism and SLE, including Caucasian, non-Caucasian, and LN subgroups. We also examined transmission of haplotypes defined by these polymorphisms. The ACE I/D polymorphism was associated with SLE among non-Caucasians (61% transmission, P = 0.026) and the 23949 (CT)(2/3) polymorphism was associated with LN among non-Caucasians (69% transmission, P = 0.014). Several haplotypes defined by these 2 markers demonstrated strikingly increased transmission among non-Caucasians (81% - 66% transmission, P = 0.0046 to 0.010). Due to the choice of study design and analytic method these results are unlikely to be due to population admixture. Our findings suggest that DNA sequence variation in the ACE gene influences the risk of developing SLE and LN.

Comparison of clinical associations of patients with vasculopathic and idiopathic downbeat nystagmus.

OBJECTIVES: To perform a pilot study comparing age and vascular risk factors of patients with vasculopathic and idiopathic downbeat nystagmus (DBN). MATERIALS AND METHODS: We reviewed the case records of 57 patients with DBN evaluated between 1987 and 1999, and classified each patient into three groups: vasculopathic, idiopathic, and other known causes. We then compared age and five weighted established stroke risk factors in patients with vasculopathic and idiopathic DBN. RESULTS: Of ten idiopathic cases, there were seven women and three men, ranging in age from 31 to 90 years (median, 79 years). Of the nine vasculopathic cases, there were seven women and two men, ranging in age from 50 to 86 years (median, 80 years). Using the Mann-Whitney U test, there was no significant difference between the two groups in terms of age (p = 0.84) or vascular risk-factor profile (p = 0.24). CONCLUSIONS: The lack of significant difference between the two groups for age and vascular risk factors supports the hypothesis that some idiopathic cases of DBN may be caused by strategically located and radiographically occult cerebral infarctions.

The Fcgamma receptor IIIA-158F allele is a major risk factor for the development of lupus nephritis among Caucasians but not non-Caucasians.

OBJECTIVE: To determine whether inheritance of Fcgamma receptor (FcgammaR) alleles conferring lower affinity for IgG binding increases the risk of developing lupus nephritis. METHODS: We compared the frequency of low-affinity alleles of two FcgammaR polymorphisms (FcgammaRIIA and FcgammaRIIIA) among 235 patients with systemic lupus erythematosus (SLE) and proven nephritis (nephritis patients) and among 352 SLE patients with no evidence of renal disease (non-nephritis control subjects). The ethnic distribution of patients in the study was 49% Caucasian, 20% Hispanic, 17% Asian/Pacific Islander, 12% African American, and 2% from other ethnic groups. All patients were genotyped for the FcgammaRIIA-131R/H and FcgammaRIIIA-158V/F polymorphisms. We used contingency table analysis to compare allele and genotype distributions for nephritis patients and nonnephritis control subjects, including ethnic-specific strata. Multivariate logistic regression analyses included sex and disease duration as covariates. RESULTS: Univariate and multivariate analyses demonstrated a striking association between the low-affinity FcgammaRIIIA-158F allele and FF genotype and the risk of nephritis among Caucasians, but not among non-Caucasians (multivariate odds ratio [OR] 2.6 for Caucasians with FF genotype), (P = 0.0017). This association was even stronger among Caucasians with severe nephritis (OR 4.4, P < 0.0001). In contrast, inheritance of the low-affinity FcgammaRIIA-131R allele (and RR genotype) was not associated with an increased risk of lupus nephritis among any of the ethnic groups examined. CONCLUSION: The FcgammaRIIIA-158F allele is a major risk factor for the development of lupus nephritis among Caucasians, but not among non-Caucasians. These results suggest that ethnic variation is critical in defining the specific genetic factors underlying the pathogenesis of SLE, and they have important prognostic and therapeutic implications as well.

Chloride-sensitive renal microangiopathy in the stroke-prone spontaneously hypertensive rat.

BACKGROUND: In the stroke-prone spontaneously hypertensive rat (SHRSP) fed a low-normal NaCl diet, we recently reported that supplemental KCl, but not KHCO(3) or K-citrate (KB/C), exacerbated hypertension and induced hyperreninemia and strokes. We now ask the following question: In these SHRSP, is either such selectively Cl(-)-sensitive hypertension or hyperreninemia a pathogenetic determinant of renal microvasculopathy? METHODS: SHRSPs were randomized to either supplemental KCl, KB/C, or nothing (control) at 10 weeks of age. Four and 14 weeks afterward, we assessed renal microangiopathy histologically and measured plasma renin activity (PRA). From randomization, blood pressure was measured radiotelemetrically and continually; proteinuria was measured periodically. RESULTS: KCl, but not KB/C, amplified renal microangiopathy and proteinuria. Four weeks after randomization, when KCl initially exacerbated hypertension, renal microangiopathy, hyperproteinuria, and hyperreninemia had not yet occurred. However, across all groups, the increment of SBP at four weeks strongly predicted its final increment, severity of renal microangiopathy, proteinuria, and PRA 14 weeks after randomization. Then, the severity of renal microangiopathy varied directly with the levels of systolic blood pressure (SBP; R(2) = 0.9, P < 0.0001), PRA (R(2) = 0.7, P < 0.0001), and proteinuria (R(2) = 0.8, P < 0.0001) as continuous functions across all treatment groups. Renal creatinine clearance was greater with KB/C. CONCLUSIONS: In the SHRSP, (1) like cerebral microangiopathy, renal microangiopathy is selectively Cl(-) sensitive and hence, systemic microangiopathy is as well; (2) Cl(-) likely amplifies microangiopathy by exacerbating hypertension and possibly also by increasing PRA; and (3) Cl(-) might increase blood pressure and PRA by further constricting the renal afferent arteriole.

Effect of angiotensin II blockade on renal injury in mineralocorticoid-salt hypertension.

Kidney function and structure were compared in control rats (group 1) and in 3 groups of rats made hypertensive by administration of aldosterone and saline for 8 weeks (groups 2, 3, and 4). Group 2 rats received only aldosterone and saline, while group 3 also received losartan and group 4 also received enalapril. Rats in all groups were subjected to uninephrectomy before beginning the experiment. Hypertension and proteinuria in rats given aldosterone and saline were not affected by losartan or enalapril (8-week values for blood pressure in mm Hg: 135+/-3 group 1, 193+/-4 group 2, 189+/-4 group 3, 189+/-5 group 4; P<0.05 groups 2, 3, and 4 versus 1; 8-week values for proteinuria in mg/d: 44+/-8 group 1, 278+/-34 group 2, 267+/-37 group 3, 289+/-36 group 4; P<0.05 groups 2, 3, and 4 versus 1). Vascular, glomerular, and tubulointerstitial injury accompanied hypertension and proteinuria at 8 weeks. Losartan and enalapril did not prevent vascular injury, which was characterized by thickening of arterial and arteriolar walls and by fibrinoid necrosis and thrombotic microangiopathy. Likewise, losartan and enalapril did not reduce the prevalence of glomerular segmental sclerosis (1+/-1% group 1, 10+/-2% group 2, 11+/-2% group 3, 13+/-2% group 4; P<0.05 groups 2, 3, and 4 versus 1) or limit tubulointerstitial injury as reflected by the volume fraction of the cortical interstitium (15+/-1% group 1, 20+/-1% group 2, 21+/-1% group 3, 21+/-1% group 4; P<0.05 groups 2, 3, and 4 versus 1). These findings suggest that local angiotensin II activity does not contribute to the development of renal injury in mineralocorticoid-salt hypertension.

Acute megakaryoblastic leukemia in Down syndrome: orbital infiltration.

PURPOSE: To describe an uncommon ocular presentation of acute megakaryoblastic leukemia in a child with Down syndrome. METHOD: Case report. Initial manifestation of disease was bilateral proptosis with secondary exposure keratitis caused by leukemic infiltration of the orbits. RESULTS: Bone marrow biopsy and immunophenotyping established the diagnosis of acute megakaryoblastic leukemia (FAB-M7). The leukemia was treated successfully with chemotherapy, with resolution of proptosis. The patient remained in remission more than 1 year after cessation of treatment. CONCLUSIONS: Bilateral proptosis can be a presenting sign of acute megakaryoblastic leukemia, a malignancy associated with Down syndrome.

Effects of endurance training on standard and signal-averaged electrocardiograms of sled dogs.

OBJECTIVE: To determine the effect of endurance training on QRS duration, QRS-wave amplitude, and QT interval. ANIMALS: 100 sled dogs in Alaska. PROCEDURE: Dogs were examined in early September (before training) and late March (after training). During the interim, dogs trained by pulling a sled with a musher (mean, 20 km/d). Standard and signal-averaged ECG were obtained before and after training. RESULTS: Endurance training significantly increased mean QRS duration by 4.4 milliseconds for standard ECG (mean +/- SEM; 62.3 +/- 0.7 to 66.7 +/- 0.6 milliseconds) and 4.3 milliseconds for signal-averaged ECG (51.5 +/- 0.7 to 55.8 +/- 0.6 milliseconds) without changing body weight. Increase in QRS duration corresponded to a calculated increase in heart weight (standard ECG, 23%; signal-averaged ECG, 27%). Signal-averaged QRS duration was correlated with echocardiographically determined left ventricular diastolic diameter for the X orthogonal lead (r = +0.41), Y orthogonal lead (r = +0.33), and vector (r = +0.35). Training also increased QT interval (234 +/- 2 to 249 +/- 2 milliseconds) and R-wave amplitude in leads II and rV2, increased peak-to-peak voltage and S-wave amplitude in the Y orthogonal lead, and decreased Q-wave amplitude in the Y orthogonal lead. CONCLUSIONS AND CLINICAL RELEVANCE: Electrocardiographic changes reflected physiologic cardiac hypertrophy in these canine athletes in response to repetitive endurance exercise. The QRS duration increases in response to endurance exercise training and, therefore, may be of use in predicting performance in endurance activities.

Transplant glomerulopathy as a cause of late graft loss.

Several pathophysiological processes contribute to chronic kidney transplant rejection. Among the most distinctive is transplant glomerulopathy, characterized by widening of the subendothelial space with accumulation of flocculent material and duplication of the basement membrane. The current study assessed the course of graft loss in patients with and without this form of injury. Twenty-five patients with prominent transplant glomerulopathy were identified from biopsies performed at a single center during 4 years. These patients were compared with control patients with a similar degree of renal dysfunction in whom biopsies showed chronic rejection without transplant glomerulopathy. Patients with transplant glomerulopathy showed an increased rate of graft loss after biopsy. Biopsies were performed longer after transplantation in these patients, however, than in control patients with an equal degree of graft dysfunction. Graft survival from the time of transplantation was therefore not different between the two groups. Morphological studies showed that transplant glomerulopathy was not associated with increased severity of chronic vascular injury characterized by arterial and arteriolar intimal thickening or hyalinosis. These findings show that transplant glomerulopathy may develop late after transplantation and separately from chronic vascular rejection. The appearance of transplant glomerulopathy on a biopsy specimen is followed by accelerated graft loss.

An inactivating point mutation in the inhibitory wedge of CD45 causes lymphoproliferation and autoimmunity.

A model has been proposed for the regulation of CD45, and by homology other RPTPs, in which dimerization inhibits phosphatase activity through symmetrical interactions between an inhibitory structural wedge and the catalytic site. Here, we report the phenotype of mice with a single point mutation, glutamate 613 to arginine, that inactivates the inhibitory wedge of CD45. The CD45 E613R mutation causes polyclonal lymphocyte activation leading to lymphoproliferation and severe autoimmune nephritis with autoantibody production, resulting in death. Both homozygotes and heterozygotes develop pathology, indicating genetic dominance of CD45 E613R. The dramatic phenotype of CD45 E613R mice demonstrates the in vivo importance of negative regulation of CD45 by dimerization, supporting the model for regulation of CD45, and RPTPs in general.