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.

Arterial Delivery of Genetically Labelled Skeletal Myoblasts to the Murine Heart: Long-Term Survival and Phenotypic Modification of Implanted Myoblasts

The ability to replace damaged myocardial tissue with new striated muscle would constitute a major advance in the treatment of diseases that irreversibly injure cardiac muscle cells. The creation of focal grafts of skeletal muscle has been reported following the intramural injection of skeletal myoblasts into both normal and injured myocardium. The goals of this study were to determine whether skeletal myoblast-derived cells can be engrafted into the murine heart following arterial delivery. The murine heart was seeded with genetically labeled C2C12 myoblasts introduced into the arterial circulation of the heart via a transventricular injection. A transventricular injection provided access to the coronary and systemic circulations. Implanted cells were characterized using histochemical staining for β-galactosidase, immunofluorescent staining for muscle-specific antigens, and electron microscopy. Initially the injected cells were observed entrapped in myocardial capillaries. One week after injection myoblasts were present in the myocardial interstitium and were largely absent from the myocardial capillary bed. Implanted cells underwent myogenic development, characterized by the expression of a fast-twitch skeletal muscle sarco-endoplasmic reticulum calcium ATPase (SERCA1) and formation of myofilaments. Four months following injection myoblast-derived cells began to express a slow-twitch/cardiac protein, phospholamban, that is normally not expressed by C2C12 cells in vitro. Most surprisingly, regions of close apposition between LacZ labeled cells and native cardiomyocytes contained structures that resembled desmosomes, fascia adherens junctions, and gap junctions. The cardiac gap junction protein, connexin43, was localized to some of the interfaces between implanted cells and cardiomyocytes. Collectively, these findings suggest that arterially delivered myoblasts can be engrafted into the heart, and that prolonged residence in the myocardium may alter the phenotype of these skeletal muscle-derived cells. Further studies are necessary to determine whether arterial delivery of skeletal myoblasts can be developed as treatment for myocardial dysfunction.

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.

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.

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.

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.

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.

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.

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.

Acute hepatitis due to fluoxetine therapy

Fluoxetine-induced hepatotoxicity is generally considered of minimal clinical importance and is not well recognized. Asymptomatic increases in liver enzyme values have been observed in 0.5% of patients who take long-term fluoxetine therapy. This report details 2 cases of acute hepatitis believed to be caused by fluoxetine. Three cases of acute hepatitis caused by fluoxetine have been reported previously. The mechanism of fluoxetine-induced hepatotoxicity is unknown. Although routine monitoring of liver function may not be cost-effective, physicians should be alert to the possibility of fluoxetine-associated hepatitis and consider early discontinuation of the drug if this condition is suspected.

Late consequences of acute ischemic injury to a solitary kidney

The sequelae of acute ischemic injury to a solitary kidney were assessed in rats subjected to right nephrectomy and transient occlusion of the left renal artery; control rats underwent right nephrectomy alone. Incomplete recovery from ischemic injury at 2 wk (serum creatinine levels of 1.1 +/- 0.2 versus 0.5 +/- 0.1 mg/dl, P < 0.05 for ischemia versus control) was followed by deterioration of renal function at 20 wk (serum creatinine levels of 1.7 +/- 0.4 versus 0.7 +/- 0.1 mg/dl, P < 0.05 for ischemia versus control). Morphologic studies showed that impairment of function after ischemic injury was associated with widespread tubulointerstitial disease. Some tubule segments were atrophic and others exhibited cystic dilation, so that the tubular cell volume fraction was reduced (37 +/- 4 versus 53 +/- 2%, P < 0.05), while the tubular lumen and interstitial volume fractions were increased (31 +/- 4 versus 23 +/- 2% and 29 +/- 2 versus 20 +/- 1%, respectively, both P < 0.05). Many glomeruli retained open capillary loops but were no longer connected to normal tubule segments (63 +/- 8 versus 15 +/- 7% of glomeruli, P < 0.05). There was a strong inverse correlation between the prevalence of such glomeruli and the GFR at 20 wk after ischemia (r2 = 0.79, P < 0.001). Tubulointerstitial disease at that time was accompanied by proteinuria and widespread segmental glomerular tuft injury. The occurrence of similar processes in human patients could contribute to the loss of graft kidneys that suffer ischemic injury during transplantation.

Digital imaging of black and white photomicrographs: impact of file size

The publication of black and white photomicrographs has a long tradition in pathology. High-resolution film and quality objectives have been the backbone of generating quality photomicrographs suitable for publication. However, the digital imaging revolution has changed the way we view and capture images. As the quality of image capture devices increases and as their price decreases, more and more investigators are using digital imaging, and the use of color digital imaging for teleconferencing, telediagnosis, and reproduction is now well established. The purpose of this study was to determine the file sizes needed to obtain publication-quality black and white images using digital imaging technology. In this study, four experts in renal pathology reviewed 70 black and white images of various file sizes obtained from specimens representing a variety of renal histopathology. Without knowledge of the file size, the four renal pathologists graded the degree of pixelation, and the overall diagnostic and publication quality of the images. In all cases, digital imaging was capable of obtaining publication quality images equal to those achieved using film. The file size needed to achieve publication quality black and white images depended on magnification, with lower magnification images requiring larger file sizes.

Contribution of tubular injury to loss of remnant kidney function

BACKGROUND

The remnant kidney model has been widely used to identify mechanisms responsible for the progression of renal disease. However, the structural changes associated with progressive loss of function in this model have not been well characterized.

METHODS

Kidney function and structure were assessed at 10 weeks (REM 10) and 25 weeks (REM 25) after five-sixths renal ablation and in control rats (Control). Serial sections were examined to relate glomerular and tubular structure in individual nephrons.

RESULTS

Remnant kidney function declined between 10 and 25 weeks after ablation (GFR 0.90 +/- 0.34 vs. 0.23 +/- 0.07 ml/min, REM 10 vs. REM 25, P < 0.05). This decline in function was associated with an increase in the prevalence of globally sclerotic glomeruli (14 +/- 10 vs. 0 +/- 0 vs. 0 +/- 0%, REM 25 vs. REM 10 vs. Control, P < 0.05 REM 25 vs. REM 10 and Control). The decline in remnant kidney function between 10 and 25 weeks was also associated with the appearance of glomeruli that were atubular (48 +/- 14 vs. 9 +/- 8 vs. 3 +/- 5%, REM 25 vs. REM 10 vs. Control, P < 0.05 REM 25 vs. REM 10 and Control) or connected to atrophic proximal tubule segments (26 +/- 10 vs. 11 +/- 6 vs. 1 +/- 2%, REM 25 vs. REM 10 vs. Control, P < 0.05 all comparisons). Atubular glomeruli, which usually had open capillary loops available for filtration, were more numerous than globally sclerotic glomeruli at 25 weeks after ablation.

CONCLUSIONS

These findings indicate that tubular injury contributes to progressive loss of renal function following reduction in nephron number.

Frequency of recurrent lupus nephritis among ninety-seven renal transplant patients during the cyclosporine era

OBJECTIVE

To determine the frequency of recurrent lupus nephritis (LN) in patients with systemic lupus erythematosus (SLE) who underwent renal transplantation.

METHODS

We reviewed the posttransplant clinical course and renal biopsy results in 97 consecutive SLE patients who underwent a total of 106 renal transplantation procedures at our center from January 1984 to September 1996.

RESULTS

There were 81 female and 16 male patients, with a mean age of 35 years. Mean duration of dialysis prior to transplantation was 33.5 months; 9 patients were never dialyzed. In all patients, the disease was clinically and serologically quiescent at the time of transplantation. The mean posttransplantation followup period was 62.6 months. Patients underwent a total of 143 posttransplant biopsies. Nine patients had pathologic evidence of recurrent LN. Six of the patients with recurrence had cadaveric grafts, 2 had living-related grafts, and 1 had a living-unrelated graft. Recurrence occurred an average of 3.1 years after transplantation; the longest interval was 9.3 years and the shortest, 5 days. Histopathologic diagnoses on recurrence included diffuse proliferative glomerulonephritis, focal proliferative glomerulonephritis, membranous glomerulonephritis, and mesangial glomerulonephritis. In 4 patients, recurrent LN contributed to graft loss. Three of the patients with recurrence had serologic evidence of active lupus, but only 1 had symptoms of active lupus (arthritis). Three patients who lost their grafts secondary to recurrent LN underwent second renal transplantation procedures and had functioning grafts at 7, 30, and 35 months, respectively.

CONCLUSION

In the largest single medical center series of renal transplant patients with SLE, recurrent LN was more common than reported in the literature, but was not always associated with allograft loss. Recurrent LN was often present in the absence of clinical and serologic evidence of active SLE.

In utero hematopoietic stem cell transplants prolong survival of postnatal kidney transplantation in monkeys

The authors hypothesized that in utero transplantation of T-cell-depleted paternal marrow into rhesus monkey fetuses would induce tolerance to postnatal kidney grafts from the marrow donor. T-cell-depleted paternal bone marrow was transplanted intraperitoneally into two female fetal rhesus monkeys at 61 +/- 1 days' gestation. Chimeric monkeys (n = 2) received kidney transplants from paternal donors. Control monkeys (n = 2) underwent kidney transplants without prior in utero stem cell transplants. Both chimeric monkeys demonstrated low level (<0.1% donor cells) engraftment in the bone marrow and peripheral blood using the polymerase chain reaction assay for the Y chromosome. The mixed lymphocyte reaction demonstrated hyporeactivity to the donor. Control animals demonstrated severe acute rejection and graft failure 1 week posttransplant. The first chimeric monkey had no significant clinical or sonographic evidence of renal failure until 7 weeks after the transplant. Biopsy findings showed mild rejection 1 week postoperatively, but rejection did not significantly progress until 5 weeks later. The second chimeric monkey had no significant clinical or sonographic changes for 4 weeks, but evidence of moderate rejection was seen on biopsy results. This monkey was given a 10-week course of immunosuppression, and had no clinical or sonographic renal deterioration, although biopsy results showed chronic rejection that was confirmed when electively euthanized 8 months later. Our data suggest that in utero transplantation of hematopoietic stem cells can increase the survival of a kidney allograft in the rhesus monkey.

Retinal function abnormalities in membranoproliferative glomerulonephritis type II

PURPOSE

To characterize retinal electrophysiologic and psychophysical abnormalities associated with membranoproliferative glomerulonephritis type II.

METHODS

Three adults with membranoproliferative glomerulonephritis type II were studied. Retinal function was measured psychophysically (automated perimetry, Farnsworth D-15 color vision testing, and dark adaptometry) and electrophysiologically (full-field flash electroretinography and electro-oculography).

RESULTS

Two symptomatic individuals had prominent drusenlike deposits and retinal pigment epithelial disturbances, findings characteristic of membranoproliferative glomerulonephritis type II retinopathy. These individuals had mild visual field and color vision abnormalities, prolonged dark adaptation, and delayed electroretinographic dark-adapted dim and bright flash responses of normal amplitude. The electro-oculogram of the most severely affected individual was abnormal. The third individual who was asymptomatic had the mildest fundus abnormalities and exhibited normal psychophysical and electrophysiologic responses.

CONCLUSIONS

Membranoproliferative glomerulonephritis type II retinopathy may be associated with symptomatic and measurable psychophysical and electrophysiologic abnormalities of retinal function.

Polyomavirus-induced interstitial nephritis in two renal transplant recipients: case reports and review of the literature

We present two case reports of renal polyomavirus infection leading to renal allograft dysfunction, review the literature of this entity, and discuss the role of specific immunosupressives. Histologically, the virus caused an interstitial infiltrate composed of plasma cells and lymphocytes, interstitial fibrosis, and tubular atrophy. Viral inclusions were seen within tubular cells on light microscopy. Electron microscopy showed viral particles of 40 to 50 nm in a characteristic paracrystalline array. Both patients had been on FK-506-based immunosuppression. In both patients, the virus appeared to clear histologically and renal function stabilized when the patients were converted to cyclosporine-based immunosuppression. Contrary to prior reports, our patients have not lost their grafts and continue to have stable, albeit reduced, graft function at 2.5 years and 4.5 years following the initial diagnosis of renal polyomavirus infection.

Atubular glomeruli in patients with chronic allograft rejection

Morphometric studies were performed in 15 patients with chronic renal allograft rejection. Biopsy cores were serially sectioned so that atubular glomeruli could be identified and volumes of individual glomeruli could be measured. Control tissue was obtained from 9 cadaver donors and 8 living donors. Serial sectioning revealed that atubular glomeruli were as common as sclerotic glomeruli in chronic rejection. The prevalence of atubular glomeruli averaged 18 +/- 15% (mean +/- SD) in recipients with chronic rejection, 2 +/- 2% in cadaver donors, and 1 +/- 3% in living donors (P<0.05, recipients vs. donor groups). In comparison, the prevalence of sclerotic glomeruli averaged 19 +/- 13%, 4 +/- 7%, and 7 +/- 10% in the three groups (P<0.05 recipients vs. donor groups). Atubular glomeruli exhibited reduced mean volume (3.1 +/- 0.9 x 10(6)micron(3) vs. 4.5 +/- 1.5 x lO(6)micron(3), atubular vs. open glomeruli in recipients, P < 0.05) but could not be distinguished from open glomeruli by their appearance on single sections. Recipients with chronic rejection exhibited tubular atrophy and interstitial fibrosis with an increase in the interstitial volume fraction to 51 +/- 14% as compared with 29 +/- 6% in cadaver donors and 17 +/- 2% in living donors (P<0.05 recipients vs. donor groups). Similar interstitial expansion was observed in recipients with a high prevalence of atubular glomeruli, recipients with a high prevalence of sclerotic glomeruli, and also in four recipients in whom the predominant form of glomerular injury was transplant glomerulopathy. These results suggest that mechanisms responsible for development of atubular glomeruli are among the processes that contribute to loss of graft function in patients with chronic rejection.

Arterial delivery of genetically labelled skeletal myoblasts to the murine heart: long-term survival and phenotypic modification of implanted myoblasts

The ability to replace damaged myocardial tissue with new striated muscle would constitute a major advance in the treatment of diseases that irreversibly injure cardiac muscle cells. The creation of focal grafts of skeletal muscle has been reported following the intramural injection of skeletal myoblasts into both normal and injured myocardium. The goals of this study were to determine whether skeletal myoblast-derived cells can be engrafted into the murine heart following arterial delivery. The murine heart was seeded with genetically labeled C2C12 myoblasts introduced into the arterial circulation of the heart via a transventricular injection. A transventricular injection provided access to the coronary and systemic circulations. Implanted cells were characterized using histochemical staining for beta-galactosidase, immunofluorescent staining for muscle-specific antigens, and electron microscopy. Initially the injected cells were observed entrapped in myocardial capillaries. One week after injection myoblasts were present in the myocardial interstitium and were largely absent from the myocardial capillary bed. Implanted cells underwent myogenic development, characterized by the expression of a fast-twitch skeletal muscle sarcoendoplasmic reticulum calcium ATPase (SERCA1) and formation of myofilaments. Four months following injection myoblast-derived cells began to express a slow-twitch/cardiac protein, phospholamban, that is normally not expressed by C2C12 cells in vitro. Most surprisingly, regions of close apposition between LacZ labeled cells and native cardiomyocytes contained structures that resembled desmosomes, fascia adherens junctions, and gap junctions. The cardiac gap junction protein, connexin43, was localized to some of the interfaces between implanted cells and cardiomyocytes. Collectively, these findings suggest that arterially delivered myoblasts can be engrafted into the heart, and that prolonged residence in the myocardium may alter the phenotype of these skeletal muscle-derived cells. Further studies are necessary to determine whether arterial delivery of skeletal myoblasts can be developed as treatment for myocardial dysfunction.

Histopathological concordance of paired renal allograft biopsy cores. Effect on the diagnosis and management of acute rejection

To assess the effect of sampling error on renal allograft biopsies, we determined the concordance of diagnoses between 2 biopsy samples from the same renal allograft and the frequency with which 1 biopsy sample would underdiagnose or lead to the undertreatment of acute rejection. Two core samples from the same allograft biopsy procedure were labeled as core A and core B and presented to both unblinded and blinded pathologists, and each pathologist independently assigned an acute and a chronic rejection grade. A set of clinical data with pertinent prebiopsy information was combined with either the core A or core B histopathological diagnosis and presented to 3 transplant nephrologists who made treatment recommendations for each combination. Two cores were obtained in 79 allograft biopsies. Core pairs differed by > or = 1 grade of acute rejection in 30% and 50% of cases for unblinded and blinded pathologist readings, respectively. Moderate or severe acute rejection would have been missed with a 1 core in 9.5% of cases, increasing to 25.6% if only biopsy pairs containing at least 1 reading of moderate or severe acute rejection are included. Therapy would have failed to be increased with a single core in 7.5% of cases, increasing to 10.5% if only pairs containing at least one recommendation of an increase in therapy are included. The use of 2 cores of renal allograft tissue provides better diagnostic information and thereby leads to appropriate increases in antirejection therapy without increasing the complication rate of the procedure.

Dilated cardiomyopathy and neonatal lethality in mutant mice lacking manganese superoxide dismutase

The Sod2 gene for Mn-superoxide dismutase (MnSOD), an intramitochondrial free radical scavenging enzyme that is the first line of defense against superoxide produced as a byproduct of oxidative phosphorylation, was inactivated by homologous recombination. Homozygous mutant mice die within the first 10 days of life with a dilated cardiomyopathy, accumulation of lipid in liver and skeletal muscle, and metabolic acidosis. Cytochemical analysis revealed a severe reduction in succinate dehydrogenase (complex II) and aconitase (a TCA cycle enzyme) activities in the heart and, to a lesser extent, in other organs. These findings indicate that MnSOD is required for normal biological function of tissues by maintaining the integrity of mitochondrial enzymes susceptible to direct inactivation by superoxide.

Intimate association of eosinophils to collagen bundles in eosinophilic myocarditis and ranitidine-induced hypersensitivity myocarditis

BACKGROUND

Eosinophilic myocarditis is an inflammatory condition of the heart in which the infiltrate is composed predominately of eosinophils.

DESIGN

We identified three cases of eosinophilic myocarditis in which the infiltrating eosinophils showed a remarkable intimate association with bundles of collagen. Two of the hearts examined were explants from heart transplant recipients with hypersensitivity myocarditis at the time of transplant and the third was from an autopsied patient with Churg-Strauss syndrome. These hearts were examined using light and electron microscopy. The cellular infiltrate in all three cases was characterized using immunoperoxidase stains with a panel including antibodies against myeloperoxidase, common leukocyte antigen (CD45), B lymphocytes (CD20), T lymphocytes (CD3), active-memory T lymphocytes (CD45RO), inactive T lymphocytes (CD45RA), and macrophages (CD68).

RESULTS

Ultrastructural examination in all three cases confirmed the apposition of eosinophils to both large bundles of collagen and smaller aggregates of collagen fibrils. The eosinophils and the bundles of collagen stained strongly for myeloperoxidase, suggesting at least partial degranulation of the eosinophils. A KP-1 stain (CD68) revealed macrophages admixed with the eosinophils adjacent to the collagen bundles, and stains for CD45RA (naive lymphocytes) and CD45RO (memory T cells) showed an interstitial infiltrate of predominantly CD45RO-positive cells. Clinically, the cardiac decompensation of one of the transplant patients was most likely due to ranitidine-induced hypersensitivity myocarditis.

CONCLUSIONS

These results suggest that some cases of eosinophilic myocarditis may be caused by the expression of novel antigens bound to collagen bundles. In one of the patients awaiting cardiac transplant, cardiac decompensation was temporally associated with ranitidine therapy, an agent not previously implicated as a cause of hypersensitivity myocarditis.

Subcutaneously tethered temporary filter: pathologic effects in swine

PURPOSE

To evaluate the histopathologic effects of the Tempo-filter, a temporary caval filter, on the caval wall and determine the feasibility of deployment and removal of the device in swine.

MATERIALS AND METHODS

Filters were placed in the infrarenal inferior vena cava of 11 swine. The tethering catheter was sutured in a subcutaneous pocket near the puncture site. The original tethering catheter used in humans and a stiffer catheter designed to prevent migration in swine were evaluated. Postplacement, mid-study, and preexplant vena cavography procedures were performed. Four swine underwent in situ dissection at 3-10 weeks. Filters were removed from seven animals just before they were killed at 1-6 weeks.

RESULTS

All filters were successfully placed. All seven filters were successfully removed at up to 6 weeks after placement. Cephalic migration of more than 1 cm was observed in 10 of 11 swine (100% of original catheters, 83% of stiff catheters). Other complications were more common with stiffer tethering catheters, including caval stenosis in 40% of original catheters and 100% of stiff catheters, filter cone thrombus in 0% and 67%, tethering catheter thrombus in 20% and 83%, pulmonary embolism in 0% and 50%, and death in 0% and 17%, respectively. There was mild vessel wall damage in the vena cava.

CONCLUSION

Placement of the Tempofilter and removal at up to 6 weeks after placement is feasible.

Epithelioid hemangioendothelioma of the lung: pleural effusion cytology, ultrastructure, and brief literature review

Epithelioid hemangioendothelioma (EHE) of the lung is a low-grade malignant tumor of vascular origin initially described under the name intravascular bronchioloalveolar tumor (IVBAT). We present a case of a 44-yr-old Caucasian female with severe radiating back pain, shortness of breath, recurrent malignant pleural effusions, and a negative malignancy workup. Cytopathologic examination of the four pleural fluid specimens revealed large undifferentiated plasmacytoid malignant cells with abundant pink and finely granular cytoplasm, round nuclei, and prominent nucleoli. The differential diagnosis based on the cytologic findings included hepatocellular, adrenal, and renal carcinomas, melanoma, mesothelioma, and neuroendocrine tumors. Electron microscopy performed on a pleural fluid specimen and subsequent histologic examination of pleural and lung biopsies established the diagnosis of EHE.

Detailed characterization of experimental acute alcoholic pancreatitis

BACKGROUND

With the ex vivo perfused canine pancreas preparation, the infusion of acetaldehyde, the primary metabolite of ethanol oxidation, plus a short period of ischemia to convert xanthine dehydrogenase to xanthine oxidase, results in the physiologic injury response of acute pancreatitis (edema, weight gain, hyperamylasemia). The free radical scavengers superoxide dismutase and catalase and a xanthine oxidase inhibitor, allopurinol, ameliorate this injury response, suggesting that toxic oxygen metabolites generated by xanthine oxidase play an intermediary role.

METHODS

The isolated ex vivo canine pancreas preparation was perfused for 4 hours, and weight gain of the preparation and amylase activity in the perfusate were monitored. Changes in pancreatic acinar cell architecture were characterized by light and electron microscopy, and intracellular phosphate metabolism was followed by magnetic resonance spectroscopy in control preparations and in glands simulating alcoholic pancreatitis.

RESULTS

Control preparations and preparations with a 1-hour period of ischemia before perfusion gained little weight (7 +/- 3 gm and 8 +/- 1 gm), amylase activity in the perfusate remained normal (933 +/- 513 units/dl and 1537 +/- 553 units/dl), and no changes in architecture were observed. Weight gain (5 +/- 6 gm) and amylase activity (1188 +/- 173 units/dl) were also normal in the preparations receiving acetaldehyde without preceding ischemia, but mild vascular and islet cell injury were observed on electron microscopy. One hour of ischemia followed by acetaldehyde infusion resulted in edema, increased weight gain (21 +/- 12 gm [p < 0.05]), and amylase activity (2487 +/- 1484 units/dl [p < 0.05]). Microscopy showed mild acinar cell damage and greater injury to the capillaries and the islets. The capillary and islet cell changes were reduced by superoxide dismutase and catalase. Intracellular adenosine triphosphate levels remained at baseline levels in the control preparations. Adenosine triphosphate decreased during ischemia but quickly recovered during perfusion without a significant difference whether acetaldehyde was infused after ischemia. An iron chelator desferoxamine ameliorated the injury response in the preparations simulating acute pancreatitis (weight gain, 13 +/- 6 gm [p = 0.09] and amylase activity, 1198 +/- 471 units/dl [p = 0.08]), but a cholecystokinin receptor antagonist L364,718 did not have an effect. A sulfhydryl group protector, dithiothreitol, decreased weight gain (10 +/- 7 gm [p = 0.06]), and amylase activity was not significantly increased over that of the control group (1582 +/- 641 units/dl), but a serine protease inhibitor phenylmethylsulphonylfluoride was ineffective.

CONCLUSIONS

In this model simulating acute alcoholic pancreatitis, both the early physiologic injury response and the early morphologic changes are mediated at least in part by free radicals, which are generated by xanthine oxidase converted reversibly from xanthine dehydrogenase. In addition to the superoxide radical, the hydroxyl radical may also be an important early intermediate step, but the cholecystokinin receptor is not.

Repeat dilation of Palmaz stents in pulmonary arteries: study of safety and effectiveness in a growing animal model

PURPOSE

This study assessed the technical feasibility and safety of repeat dilation of Palmaz stents in growing pulmonary arteries.

MATERIALS AND METHODS

Palmaz stents (1.2 cm long) were placed percutaneously into the pulmonary arteries of 20 newborn lambs. After 4 months, pulmonary arteriography was performed. Where vessel growth in excess of stent diameter had created a stenosis (> 15%), stents were dilated again percutaneously. Six months later, pulmonary arteriography was performed, before the animal was killed and histologic examination performed.

RESULTS

Twenty-four pulmonary artery stent placements were attempted; 23 were successful. One stent placement was unsuccessful owing to stent displacement from the balloon. Acute complications included branch pulmonary artery occlusion (n = 3) and stent displacement from the delivery balloon (n = 2). At 4 months, the desired degree of stenosis (> 15%) was achieved in 11 animals. The average stenosis was 35% (standard deviation, 16%; range, 17%-66%). The mean predilation stent diameter was 6 mm +/- 1.1 (range, 4-8 mm), and the final diameter of 8 mm +/- 1.4 (range, 6-10 mm), represented a 35% mean increase (P < .001). Complications included stent (n = 1) and branch vessel (n = 1) thrombosis. At 6-month follow-up, all stents were patent. Areas of previously noted branch thrombosis were fully recanalized in all cases. At histologic inspection, only a thin layer of neointima was found on the stents.

CONCLUSION

Repeat dilation of Palmaz stents may be safely performed in growing pulmonary arteries in an animal model. Neointimal hyperplasia is minimal in pulmonary artery stents.

Palmaz stent in the treatment of central venous stenosis: safety and efficacy of redilation

PURPOSE

To assess the safety and efficacy of redilation of central venous stents in a growing animal model.

MATERIALS AND METHODS

Palmaz stents were placed in the inferior vena cava (IVC) in 18 newborn lambs. After 5 months, vena cavography was performed. Those animals in which growth of the IVC adjacent to the stent and/or neointimal hyperplasia had resulted in a stenosis were considered candidates for redilation. Repeat vena cavography, intravascular ultrasound, and histologic examination were performed at 2 or 6 months.

RESULTS

A stenosis of > 20% was demonstrated in 13 animals. Redilation was performed, and a 50% mean increase in stent diameter was achieved. There were no immediate complications. Late complications included nonocclusive laminar clot (n = 2), and a bar of tissue dividing but not occluding the caval lumen (n = 1). Moderate neointimal hyperplasia occurred in all stents. Stent compression (unrelated to redilation) occurred in seven animals.

CONCLUSION

Palmaz stents can be redilated safely and effectively in an animal model of growing central veins.

Cytopathology of pleural effusions after radiotherapy

The cytomorphology of pleural effusions following ionizing radiotherapy (IRT) has not been studied systematically. To determine if IRT produces alterations in pleural fluids that affect the cytopathologic interpretation of these specimens, two reviewers, without clinical information, independently assessed 55 specimens obtained following IRT and 39 control specimens obtained from nonirradiated cancer patients. None of the 24 cytologic features studied were identified significantly more frequently by both reviewers in the irradiated specimens. Only one feature (bizarre cells) was found to occur significantly more frequently in the irradiated specimens (36% versus 15%, P = .03) by either reviewer (reviewer B). Four other features showed a tendency to occur more frequently in the irradiated fluids by one or the other reviewer. They included degenerative changes (27% versus 13%, P = .09 [reviewer A]), smudgy chromatin (16% versus 5%, P = .09 [reviewer A]), large cytoplasmic vacuoles deforming the nuclei (44% versus 26%, P = .07 [reviewer B]) and cytomegaly (38% versus 23%, P = .12 [reviewer B]). The utility of these five features in identifying irradiated specimens was rigorously retested in a second masked review conducted jointly by the two pathologists. None of these features was found more frequently in the irradiated specimens in the second analysis. The results suggest that IRT does not consistently produce distinctive cytologic changes in pleural effusions and that a history of IRT should not affect the interpretation of these specimens.

Myocarditis associated with doxorubicin cardiotoxicity

In contrast to previous reports, the authors were impressed by the frequency of myocarditis in the endomyocardial biopsy specimens of patients treated with anthracyclines. To examine this, they reviewed the histologic and electron microscopic results and immunoperoxidase stains of myocardial biopsy specimens from 11 patients with doxorubicin cardiotoxicity grades 1.0-3.0. Immunoperoxidase stains for lymphocytes, macrophages, and endothelial cells and induced expression of Class II antigen were performed using the avidin-biotin complex procedure. A full panel of monoclonal antibodies was employed on fresh-frozen tissue; a smaller panel was used with formaldehyde-fixed paraffin-embedded material. Four of the 11 endomyocardial biopsy specimens showed myocarditis, and 2 showed borderline myocarditis by the Dallas criteria. The infiltrating lymphocytes were generally characterized as T lymphocytes and were associated with induced Class II antigen expression by arterial endothelial cells. In addition, foci of replacement fibrosis, suggesting a chronic process, were identified. Although this association does not prove a causal relationship, these results suggest that myocarditis can be a component of doxorubicin-induced myocardial injury.

Ultrastructural evidence of cell-mediated endothelial cell injury in cardiac transplant-related accelerated arteriosclerosis

Accelerated arteriosclerosis secondary to chronic allograft rejection is a major long-term complication of heart transplantation. Accelerated arteriosclerosis has been associated with an endothelialitis, and the majority of the involved inflammatory cells are T lymphocytes and macrophages. Coronary arteries from six heart allograft recipients with transplant-related arteriosclerosis were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Four hearts were explants from heart transplant recipients with severe accelerated arteriosclerosis who were undergoing retransplantation, and two were obtained from autopsied recipients. The patients ranged in age from 6 to 60 years (mean, 44 years). The graft survival for these six hearts ranged from 1.4 to 5.6 years (mean, 4.3 years). Lymphocytes, macrophages, and smooth muscle cells were identified by TEM in the intimas of all the vessels examined. The lymphocytes were often in contact with macrophages or in close proximity to injured endothelial cells. Areas of endothelial injury were characterized by vacuolization of endothelial cells and partial denudation of the endothelium with fibrin deposition. SEM also revealed endothelial cell injury with disorganization of the endothelium and gaps between endothelial cells. Leukocytes and platelets were often noted in these gaps. These findings suggest that accelerated arteriosclerosis in heart transplant recipients is associated with an accumulation of macrophages, lymphocytes, and smooth muscle cells in the intima as well as with lymphocyte-directed endothelial injury.

Progressive hemochromatotic cardiomyopathy despite reversal of iron deposition after liver transplantation

Dilated cardiomyopathy is a frequent and serious complication of idiopathic hemochromatosis. The mechanism by which disordered iron metabolism induces heart failure is not entirely understood, but myocardial dysfunction appears to be intimately related to the deposition of iron in myocytes. Cardiac function characteristically worsens or improves in proportion to the degree of iron accumulation in cardiac myocytes. The authors report the case of a 47-year-old man with idiopathic hemochromatosis and cirrhosis who developed symptoms of congestive heart failure and was found to have dilated cardiomyopathy 7 months after receiving a liver transplant. An initial endomyocardial heart biopsy demonstrated severe iron deposition in myocytes. The patient's heart failure worsened in the next 3 years and he eventually required a heart transplant. Examination of the explanted heart revealed dilated cardiomyopathy, but the previously demonstrated iron deposits in the cardiac myocytes were depleted. This "uncoupling" of cardiac function and cardiac iron load suggests that a threshold may be reached at which point the metabolic and ultrastructural derangements of iron deposition are no longer reversible, even with the removal of the inciting agent. Furthermore, displacement of myocyte iron stores after liver transplantation implicates altered hepatic iron metabolism as a primary or contributing mechanism in the pathophysiology of idiopathic hemochromatosis.

Acute effects of a nucleoside analog dideoxyinosine (DDI) on the pancreas

Dideoxyinosine (DDI, Videx) is a recently developed nucleoside analog with activity against the human immunodeficiency virus. A significant number of patients with AIDS or AIDS-related complex treated with DDI have developed acute pancreatitis. This study was performed to investigate the acute effects of DDI on the pancreas utilizing an isolated ex vivo perfused canine pancreas preparation. Control preparations remained normal throughout a 4-hr perfusion period. The addition of 12.5 mg of DDI to the perfusate (ca. 100 mumol/liter) did not induce any changes in the preparation. The addition of 62.5 mg of DDI to the perfusate (ca. 500 mumol/liter) did not induce changes in the gross appearance, weight gain, or amylase activity. However, the arterial pressure and the oxygen consumption of the preparation decreased significantly after the administration of DDI. The amount of zymogen in the acinar cells also decreased, as evaluated by electron microscopy. Protein secretion increased temporarily, probably as a result of acinar cell emptying (increased secretion without new synthesis). Water and bicarbonate secretion were also increased during the fourth perfusion hour.