C5a is important in the tubulointerstitial component of experimental immune complex glomerulonephritis.

Interstitial injury is the hallmark of glomerulonephritis which is progressing to end-stage renal disease (ESRD). In humans and experimental animals, we have shown that interstitial disease is accompanied by up-regulation of complement components in tubular epithelial cells. Glomerulonephritis was induced in mice by the intraperitoneal injection of horse spleen apoferritin (HSA) and lipopolysaccharide (LPS). In addition to wild-type C57/B6 mice, animals in which the C5a receptor had been deleted (C5aR KO) were used. Animals were killed after 3 or 6 weeks, and kidneys harvested. At three weeks, both groups had evidence of mild mesangial matrix expansion and increased cellularity; there were no crescents, sclerotic lesions, or interstitial disease. At six weeks, glomerular lesions were advanced, but identical in the two groups. Both groups had evidence of an identical pattern of C3 gene expression in the tubular epithelium by in situ hybridization. There was a marked difference, however, in the extent of interstitial injury. Wild-type animals had significantly greater numbers of infiltrating interstitial cells, greater expansion of the peritubular space, more tubular atrophy, and more apoptotic tubular cells than did C5aR KOs. The anaphylotoxic fragment of C5, C5a, is not likely to be important in the glomerular component of this model of progressive glomerulonephritis. On the other hand, the interstitial component is markedly attenuated in knockout animals. These data support a role for complement in the interstitial component of this glomerulonephritis model. They are consistent with our hypotheses of a role for complement in the progression of some forms of glomerulonephritis to ESRD.

Evidence of a role for C4 in modulating interstitial inflammation in experimental glomerulonephritis.

Activation of C4 releases into the fluid phase a fragment of the alpha chain, C4a. Unlike the analogous fragments of C3 and C2, there is no evidence for an anaphylatoxic effect of C4a. There is actually some in vitro evidence that it could have a modulating effect on inflammation by inhibiting monocyte chemotaxis. We induced an immune complex glomerulonephritis in wild-type (WT) and C4 knock out (C4KO) mice. Although the glomerular component of the disease did not differ in the two groups of animals, there were marked differences in the accompanying tubulo-interstitial injury. Compared to WT animals, the C4KO mice had significantly more infiltrating interstitial cells (1910 vs 2720/mm(2)), foci of tubular atrophy (6.3 vs 14.8/section), and interstitial space (22 vs 30% of cortex). C4 is expressed constitutively by renal tubular epithelial cells. These data support a role for such local C4 in modulating interstitial inflammation, consistent with in vitro experiments.

Glomerulonephritis associated with deficiencies and polymorphisms of complement components encoded in the class III region of the MHC.

An association between the complement system and immune complex glomerular disease in humans has long been recognized. In fact, much of our early understanding of the immunochemistry of complement activation developed with the study of acute and chronic glomerulonephritis (1). This manuscript will examine associations between glomerulonephritis and the three complement components encoded within the major histocompatibility complex: C4, C2, and factor B (B). The mechanisms by which deficiencies or polymorphisms in these components can mediate disease will be examined.

The complement system in renal diseases.

The complement system has long been recognized as having a role in immune glomerular disease. This review provides an update on this association, some strategies for the clinical testing of complement in disease, and a brief commentary on current research directions. Evidence of complement activation in glomerulonephritis comes from characteristic patterns of a decrease in the serum concentrations of specific components, some of which are virtually diagnostic of certain nephritides. These patterns are often accompanied by the presence of complement components in the glomeruli and the detection of complement breakdown products in the circulation. In certain diseases, circulating complement-activating substances can be detected. Although there are over 20 complement proteins, clinical analysis is most often directed at C3 and C4, with occasional measurement of B and C5. Recently, a variety of mechanisms for complement-induced injury has been recognized. These mechanisms go far beyond simple passive lysis of erythrocytes, the earliest functional effect of complement studied. The role of such mechanisms in renal disease is just beginning to be studied. Local synthesis of complement components in the kidney may play a role both in host defense and in the promotion of interstitial inflammation and scarring. Such mechanisms will likely be defined more precisely with the availability of animals with specific complement deficiencies. Ultimately, an understanding of the role of complement in renal disease may permit specific targeted inhibition of one or more complement functions as a form of therapy.

Use of assistive devices to address hearing impairment by older persons with disabilities.

Hearing impairment impacts on the lives of almost half of people over the age of 65. For many people, a hearing aid or other assistive device can enhance communication. However, there is a high rate of dissatisfaction with hearing aids among those who currently use, or have used them in the past. This study of 227 elders with hearing impairment sought to gain a description of their multiple needs relative to demographics, health status physical status, and psychosocial status. Furthermore, we compared along the same dimensions the 227 elders with hearing impairment with 495 frail elders who reported no hearing impairment. We found that hearing-impaired elders are older, have poorer eyesight and have a high level of co-morbidity, especially with arthritis and heart and circulatory conditions. We also found a higher rate of depression among those with hearing impairment. Although hearing aid use increased as the impact of impairment on activity increased, three-quarters of those who reported that hearing impairment had a large impact on daily life did not use a hearing aid. A factor relating to hearing aid use was race; being Caucasian, and living alone. Study participants listed their reasons for dissatisfaction or non-use of their hearing aids and provided suggestions for hearing aid design.

The C5a receptor is expressed by human renal proximal tubular epithelial cells.

The C5a receptor is expressed by a variety of cell types. These studies demonstrate by immunohistochemistry that the receptor is present on the surface of proximal and distal tubular epithelial cells from normal kidney. In addition, the receptor was detected on transitional epithelial cells of the ureter and bladder. Primary proximal tubular cultures and a proximal tubular cell line both also expressed the C5a receptor, as demonstrated by immunofluorescence and by FACS analysis. The presence of mRNA encoding the receptor was confirmed by reverse transcriptase-polymerase chain reaction analysis. As opposed to its effect on glomerular mesangial cells, the receptor did not mediate a proliferative response by the proximal tubular cells. C5a also did not enhance the synthesis/secretion of transforming growth factor-beta 1, monocyte chemoattractant protein-1, platelet-derived growth factor-AB or tumour necrosis factor-alpha by cultured proximal tubular cells. Therefore, although the C5a receptor clearly is expressed by proximal tubular cells, clarification of its functional relevance on this cell type awaits further studies.

Evidence of a role for local complement expression in a murine model of progressive glomerulonephritis.

C57/B6 mice received intraperitoneal horse spleen apoferritin (4 mg) with lipopolysaccharide (0.05 mg); control mice received 0.15 M NaCl. Control and treated animals were killed weekly for 6 wk; blood and urine specimens were obtained, and tissue samples were secured. Treated animals showed evidence of significant chronic disease, with proteinuria, hematuria, and uremia. A mild glomerulonephritis was present at 2 wk, with significant proliferative glomerulonephritis at 4 wk, progressing to chronic disease with tubulointerstitial changes at 6 wk. Changes at each time period were uniform between animals. C3 mRNA was first detected by in situ hybridization at 3 wk. Message was restricted to proximal tubular and periglomerular epithelial cells. Presence of C3 message preceded the development of interstitial inflammation and fibrosis by 1-2 wk, and its location and intensity paralleled the evolving interstitial disease. Although extensive mesangial C3 protein deposits appeared early, there was never C3 message in glomeruli or infiltrating cells. Before C3 message became apparent, two cytokines known to up-regulate C3 transcription in vitro, IL-1 and IL-6, were detected by immunohistochemistry. The temporal sequence in this model is consistent with our hypothesis that local synthesis and activation of C3 in tubular epithelium is important to the interstitial component of chronic glomerulonephritis. The process is independent of the deposition of circulating complement in the glomerulus, but may be triggered by glomerular cytokines.

The effect of a teaching award on the quality of continuing medical education participant evaluations.

OBJECTIVE: To improve compliance with the completion of speakers' evaluation forms in a pediatric hospital continuing medical education program. DESIGN: Preintervention and postintervention analysis. SETTING: Pediatric hospital in Cincinnati, Ohio. PARTICIPANTS: Attendees at pediatric grand rounds programs. MAIN OUTCOME MEASURE: Analysis of speaker evaluation forms for each of 20 pediatric grand rounds programs were used as the basis for speakers' awards. RESULTS: Spontaneous written comments were found on a mean of 7.3 evaluations per preintervention program and 13.5 evaluations per postintervention program (P<.01). The distribution of objective scores in 3 items examined was wider postintervention than preintervention (P<.01). CONCLUSION: When participants in continuing medical education programs know that their evaluations of an activity are used as the basis for an educational award, they may be more reflective in completing such evaluations.

Conjunctive effects of fibroblast growth factor and glycosaminoglycan on bone metabolism in neonatal bartter syndrome.

The calciotropic activity of urine from a subject with neonatal Bartter syndrome (NBS) has been partially purified using ion-exchange and gel chromatographic techniques. A bioassay using bone disks from rat calvaria was used to estimate calciotropic activity, which in the urine of the subject with NBS appears to be due to basic fibroblast growth factor (bFGF) bound to a glycosaminoglycan susceptible to heparitinase digestion. The calciotropic activity is eluted from DEAE-Sephacel and Sepharose CL-6B in a narrow band in association with metachromatic material and is destroyed by heparitinase and blocked by an antibody to bFGF. After treatment of purified preparations with heparitinase, a component that is inactive alone but develops calciotropic activity in association with heparin can be isolated by affinity chromatography on heparin-Sepharose columns. This component is recovered from the column at NaCl concentrations expected to elute bFGF and is inactivated by antibodies to bFGF. No calciotropic activity can be shown in glycosaminoglycan-containing fractions from urine from a normal boy or a normal man, but such fractions exhibit calciotropic activity if bFGF is added to the assay system. When bFGF is added to urine from either normal subject followed by ion-exchange chromatography on DEAE-Sephacel, calciotropic activity is eluted at NaCl concentrations closely similar to those found to elute calciotropic activity from the urine of the NBS subject. It appears that the abnormal findings in NBS urine are due to excess bFGF, although they could be due to some abnormality of the glycosaminoglycan component.

Climbing harness fit in kidney transplant recipients.

OBJECTIVE: The superficial location of renal transplants places them at risk for traumatic damage. Significant injuries have been reported from automobile seat belts, for example. This study was designed to assess the potential for direct transplant injury from the use of climbing harnesses. METHODS: Ten patients with kidney transplants were fitted with a variety of climbing harnesses after the locations of their grafts were defined. RESULTS: With the exception of two harnesses in a single patient, all devices came into contact with all transplants. CONCLUSION: Sports requiring the use of climbing harnesses (eg, rock climbing, rappelling, and challenge course participation) may be unsafe for recipients of kidney transplants.

Modular variations of the human major histocompatibility complex class III genes for serine/threonine kinase RP, complement component C4, steroid 21-hydroxylase CYP21, and tenascin TNX (the RCCX module). A mechanism for gene deletions and disease associations.

The frequent variations of human complement component C4 gene size and gene numbers, plus the extensive polymorphism of the proteins, render C4 an excellent marker for major histocompatibility complex disease associations. As shown by definitive RFLPs, the tandemly arranged genes RP, C4, CYP21, and TNX are duplicated together as a discrete genetic unit termed the RCCX module. Duplications of the RCCX modules occurred by the addition of genomic fragments containing a long (L) or a short (S) C4 gene, a CYP21A or a CYP21B gene, and the gene fragments TNXA and RP2. Four major RCCX structures with bimodular L-L, bimodular L-S, monomodular L, and monomodular S are present in the Caucasian population. These modules are readily detectable by TaqI RFLPs. The RCCX modular variations appear to be a root cause for the acquisition of deleterious mutations from pseudogenes or gene segments in the RCCX to their corresponding functional genes. In a patient with congenital adrenal hyperplasia, we discovered a TNXB-TNXA recombinant with the deletion of RP2-C4B-CYP21B. Elucidation of the DNA sequence for the recombination breakpoint region and sequence analyses yielded definitive proof for an unequal crossover between TNXA from a bimodular chromosome and TNXB from a monomodular chromosome.

Continuous venovenous hemodiafiltration in the treatment of acute hyperammonemia.

Acute hyperammonemia is an emergent cause of central nervous system dysfunction for which renal replacement therapy is advocated. We report the successful use of continuous venovenous hemodiafiltration in this metabolic emergency, and report the calculated ammonia clearances for both continuous venovenous hemofiltration and hemodiafiltration.

Immunoglobulin M and C1q mesangial labeling in IgA nephropathy.

Colabeling with complement compont C1q or immunoglobulin M (IgM) is occasionally reported in biopsy specimens from patients with IgA nephropathy. The significance of this finding has been questioned. In 83 children and young adults with otherwise typical IgA nephropathy, 15 patients had more than trace mesangial labeling for IgM or C1q. Of these, 14 patients (93%) had greater than 1 + proteinuria at the time of biopsy. This was in marked distinction to the patients with no mesangial labeling for these reactants, only 15% of whom had greater than 1 + proteinuria. The children with IgM or C1q colabel did not differ from those lacking this finding in age at presentation, length of follow-up, or current renal function. In childhood IgA nephropathy, colabeling with IgM or C1q is seen frequently, probably is a function of heavy proteinuria at the time of biopsy, and does not contribute adversely to outcome.

Humoral factor in children with neonatal Bartter syndrome reduces bone calcium uptake in vitro.

The neonatal Bartter syndrome (NBS) is associated with a complex disorder of mineral metabolism in children, including hypercalciuria, nephrocalcinosis, and diminished bone mineral density. Although cyclooxygenase inhibition usually brings about improvement in these findings, there is a variable component which is resistant to such therapy in many children. The factor mediating this disorder has not been identified. Blood and urine from 12 children with NBS were examined. When compared with samples from normal children and adults, all (NBS) sera reduced bone calcium uptake in a bone disc bioassay. This effect persisted in the presence of parathyroid hormone (PTH) antibody and PTH receptor blockade, indicating that neither PTH nor PTH related peptide was responsible. It was eliminated by indomethacin, suggesting that prostanoid generation was essential. Protamine was also inhibitory, as was the addition of ecteola, an anion binder. Activity could be recovered from ecteola by elution with hypertonic buffer. Urine samples from children with NBS had the same calcitropic effect. The agent was removed by ecteola and recovered by hypertonic elution. Activity was eliminated by protamine and by heparinase, but not by trypsin digestion. Size exclusion centrifugation showed that the activity was associated with a material between 10 and 30 kilodaltons. Finally, urine ecteola eluates from NBS patients raised serum concentrations of calcium after intraperitoneal injection in rats. These data suggest that children with NBS have a calcitropic substance in their serum and urine which is not found in normal individuals. The substance is heparin like, and mediates its effects through prostanoid production. These studies provide additional evidence against a direct renal cause of the urinary calcium disturbance characteristic of the disorder.

Total anatomic urinary tract replacement and renal transplantation: a surgical strategy to correct severe genitourinary anomalies.

During renal transplantation, the donor ureter is normally anastomosed to the recipient bladder. However, preexisting anomalies of the lower urinary tract or previous surgical interventions may render the recipient bladder unusable. Although in such situations urine may be externalized via cutaneous ureterostomy or an ileal conduit, both techniques are frequently complicated by bacterial colonization or chronic infection. To overcome these problems, the authors have been treating such children via extensive, staged, bladder reconstruction (augmentation) before transplantation. On rare occasions, however, the absence of a usable bladder necessitates the creation of a complete neobladder from other visceral tissues. The authors present two cases in which patients underwent complete anatomic reconstruction of the lower urinary tract before renal transplantation. This approach results in the optimal environment for allograft function and leads to a greater rehabilitation than that achieved with urinary diversion.

The phenotype of SLE associated with complete deficiency of complement isotype C4A.

Complete deficiency of the complement C4A isotype is a known genetic risk factor for systemic lupus erythematosus (SLE). The disease phenotype of C4A-deficient patients has never been defined. Among 200 patients with SLE from five centers, 18 (9%) with C4A deficiency were identified. These individuals were compared to those who were C4A replete with regard to a series of clinical and serologic features. The only significant differences between the two groups were in the presence of renal disease (C4A deficient, 11%; C4A replete, 46%; P < 0.006) and a decrease in the serum concentrations of C3 (C4A deficient, 11%; C4A replete, 35%; P < 0.04). There was also a trend for the C4A-deficient individuals to have milder disease. In light of the tendency for C4A-deficient individuals to have lower serum concentrations of C4, it is important that such patients not be subjected to overly aggressive efforts to "normalize" their C4 levels.