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Objectives Primary cilia are sensory organelles which co-ordinate several developmental/repair pathways including hedgehog signalling. Studies of human renal allografts suffering acute tubular necrosis have shown that length of primary cilia borne by epithelial cells doubles throughout the nephron and collecting duct, and then normalises as renal function returns. Conversely the loss of primary cilia has been reported in chronic allograft rejection and linked to defective hedgehog signalling. We investigated the fate of primary cilia in renal allografts suffering acute rejection. Results Here we observed that in renal allografts undergoing acute rejection, primary cilia were retained, with their length increasing 1 week after transplantation and remaining elevated. We used a mouse model of acute renal injury to demonstrate that elongated renal primary cilia in the injured renal tubule show evidence of smoothened accumulation, a biomarker for activation of hedgehog signalling. We conclude that primary cilium-mediated activation of hedgehog signalling is still possible during the acute phase of renal allograft rejection.

Primary focal segmental glomerulosclerosis is an important cause of end-stage kidney disease with a high rate of recurrent disease after kidney transplantation. Current therapy achieves remission in only half of patients. Recent interest has focused on the potential role of galactose in binding and inactivating the putative circulating permeability factor, supported by in vitro and clinical case report studies. Orally active and without major adverse effects, galactose has a favourable treatment profile compared with current immunosuppressive treatment options. We describe our experience using galactose therapy in two patients with recurrent focal segmental glomerulosclerosis after renal transplantation. Galactose was associated with symptomatic improvement and stabilization of graft function in one case; the other case was complicated by concurrent malignancy. In both cases, we observed a marked reduction in proteinuria with galactose treatment.

In diabetic patients with acute kidney injury (AKI), kidney biopsy often reveals non-diabetic kidney pathology. This case describes a patient with known Type 1 diabetes who presented with AKI, nephrotic syndrome and haematuria. Combination pathology of seronegative anti-glomerular basement membrane antibody-mediated glomerulonephritis (anti-GBM GN), membranous nephropathy (MN) and diabetic nephropathy (DN) was demonstrated. Strong linear GBM IgG-staining on biopsy with crescentic GN and clinical AKI led to a diagnosis of anti-GBM GN, although serum antibodies were not detectable. Features of DN, Kimmelstiel–Wilson nodules and albumin staining were also present, along with features of MN, such as subepithelial deposits on electron microscopy. Despite treatment with immunosuppression and plasmapheresis, there was no recovery of kidney function. Coexisting anti-GBM GN and MN is well recognized, but the concurrent diagnosis with DN has not been described.

Purpose To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and ≤1 mm), or involved. Results The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was ≤10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin ( P 30 mm ( P =.03), premenopausal status ( P =.03), and negative progesterone receptor status ( P =.05). Conclusions A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

OBJECTIVES The use of colistin in the treatment of life-threatening Gram-negative infections is associated with a high rate of nephrotoxicity that is dose limiting. This study aimed to examine the nephroprotective effect of ascorbic acid against colistin-induced nephrotoxicity. METHODS Rats were treated intravenously twice daily with saline, colistin (cumulative dose of 36.5 mg/kg), a combination of ascorbic acid (50 or 200 mg/kg) and colistin, or ascorbic acid (200 mg/kg) over 7 days. Colistin-induced apoptosis was examined in rats over 5 days and in vitro using rat renal proximal tubular cells NRK-52E over 24 h with and without ascorbic acid. The effect of co-administered ascorbic acid on colistin pharmacokinetics was investigated. RESULTS The 24 h urinary excretion of N-acetyl-β-D-glucosaminidase, a sensitive marker for tubular damage, was significantly lower (P < 0.0001) in the colistin/ascorbic acid 200 mg/kg group. Significant histological abnormalities (P < 0.01) were detected only in the kidneys of the colistin group, which also had the highest percentage (30.6 ± 7.8%) of apoptotic cells (P < 0.005). In the cell culture studies, the percentage of apoptotic cells was significantly higher in the presence of 0.1 mM colistin alone (51.8 ± 2.0%; P < 0.0001) than in the presence of ascorbic acid, which decreased the apoptotic effect in a concentration-dependent manner. Ascorbic acid (200 mg/kg) altered colistin pharmacokinetics, as the total body clearance decreased from 3.78 ± 0.36 mL/min/kg (colistin group) to 2.46 ± 0.57 mL/min/kg (P = 0.0024). CONCLUSIONS This is the first study demonstrating the protective effect of ascorbic acid against colistin-induced nephrotoxicity and tubular apoptosis. Co-administration of ascorbic acid has the potential to increase the therapeutic index of colistin.

SUMMARY: Background: Diabetic nephropathy is a major global health problem. Progression to renal failure is common; however, the mechanisms are unknown. Experimental models suggest a role for macrophages. Therefore, macrophage accumulation and its relationship to the subsequent clinical course were studied. Methods: A retrospective study of baseline histology and the subsequent clinical course over at least 5 years involving 20 consecutive patients with a histological and clinical diagnosis of diabetic nephropathy was performed. The relationship between macrophage accumulation in renal biopsy tissue (KP-1/anti-CD68+ cells), baseline measures of known predictors of progression (proteinuria, tubulointerstitial damage, myofibroblast accumulation) and progression over 5 years (plot of reciprocal of serum creatinine) was quantified. Results: Accumulation of macrophages was apparent in the glomeruli (2.8 + 0.7/gcs vs 1.0 + 0.2 for normals, P = not significant) and interstitium (296.9 + 63.3/mm2vs 19.0 + 1.3/mm2 for normals, P = 0.002) of patients with diabetic nephropathy. Glomerular macrophage number correlated with baseline serum creatinine (r = 0.548, P = 0.012) but not with progression of renal failure as glomerular macrophages were prevalent in early, but not advanced diabetic nephropathy. Interstitial macrophage accumulation correlated strongly with serum creatinine (r = 0.649, P = 0.002), proteinuria (r = 0.779, P

Macrophage migration inhibitory factor (MIF) promotes macrophage accumulation and leucocyte activation during inflammation. Macrophage migration inhibitory factor is upregulated in intrinsic renal cells in many types of kidney diseases, and has a pathogenic role in rat crescentic nephritis. However, little is known about the factors that regulate the production and secretion of MIF in kidney cells. In this study, we evaluated whether interferon-gamma (IFN-gamma), a cytokine implicated in the development of kidney disease and a potent inducer of MIF production in macrophages, could promote MIF synthesis and secretion from renal tubular epithelial cells. Northern blot analysis detected constitutive expression of MIF mRNA in rat tubular epithelial cells (NRK52E), which increased twofold after a 6-h stimulation with IFN-gamma. Macrophage migration inhibitory factor protein was found only in the cytoplasm of NRK52E cells. Following IFN-gamma stimulation, intracellular MIF in NRK52E cells was rapidly secreted with a maximal reduction of 50% after 20 min, which returned to normal levels after 2-4 h. Rapid secretion of MIF in response to IFN-gamma was also seen in rat mesangial cells. These findings indicate that IFN-gamma induces rapid secretion of MIF by tubular epithelial cells, and suggest that this may be an important mechanism leading to inflammatory cell accumulation and activation during kidney disease.

Production of macrophage-colony stimulating factor (M-CSF), the major macrophage growth factor, is increased in tissues during inflammation. Therefore, w determined whether M-CSF, acting through its receptor c-fms, contributes to macrophage accumulation at a site of tissue injury. Daily treatment with anti-c-fms or control antibody was given to mice with renal inflammation resulting from unilateral ureteric obstruction (UUO). Following UUO, kidney M-CSF mRNA increased in association with macrophage accumulation (days 1, 5, and 10) and local macrophage proliferation (days 5 and 10). Anti-c-fms treatment caused a minor inhibition of monocyte recruitment at day 1, reduced macrophage accumulation by 75% at day 10, but did not affect blood monocyte counts or the CD4 and CD8 lymphocytic infiltrate. Prevention of macrophage accumulation by anti-c-fms treatment was associated with a 90% reduction in local macrophage proliferation at days 5 and 10 without evidence of increased macrophage apoptosis. Therefore, M-CSF/c-fms signaling plays a key role in macrophage accumulation during tissue injury.

SUMMARY: Current experimental models of glomerulonephritis focus on the acute phases of renal injury. Models replicating the features of human glomerulonephritis, including hypertension, protein-uria, hyperlipidaemia, renal fibrosis and renal failure, are lacking. the aim of this experiment was to define a rat model of glomerulonephritis that replicates the features of progressive glomerulonephritis in humans. Passive accelerated antiglomerular basement membrane disease was induced in inbred Sprague-Dawley rats. Age-matched control rats received pre-immunisation, but were given saline rather than nephrotoxic serum. Groups of diseased rats (n=4–6) were killed at 4, 6 and 7 weeks, and tissues were extracted for histological assessment. Diseased rats developed renal failure over 7 weeks (91% reduction in creatinine clearance vs controls at week 7, P< 0.001). Proteinuria reached a plateau from week 2 to week 7 (269.1 ± 107.9 mg/24h vs 1.00 ± 0.18 mg/mL for controls at week 7, P< 0.001). Diseased rats became hyperlipidaemic (108% increase in cholesterol vs control, P

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays a pathogenic role in experimental crescentic glomerulonephritis (GN). Renal expression of MIF is also upregulated in human GN and correlates with leukocytic infiltration, histologic damage, and renal dysfunction. The study presented here examined whether MIF can be measured in urine and if so, whether the urine MIF concentration reflects the degree of renal injury. Urine and serum MIF was measured by enzyme-linked immunosorbent assay in 10 normal healthy volunteers and in a cohort of 63 patients with GN (2 thin basement membrane disease [TBM], 15 membranous GN, 10 focal segmental glomerular sclerosis, 20 IgA glomerularnephritis, 11 crescentic GN, 10 systemic lupus erythematosis World Health Organization class IV). Renal MIF expression was assessed by immunostaining of biopsy tissue. MIF was detected in urine from normal volunteers (mean +/- SD; 191 +/- 132 pg MIF/micromol creatinine). The urine MIF concentration was unchanged in patients with nonproliferative nephropathies (343 +/- 397 pg MIF/micromol Cr) but was increased 3.4-fold in proliferative nephropathies (645 +/- 527 pg MIF/micromol Cr; P < 0.05 versus normal and nonproliferative). Stratified analysis showed the greatest increase in urine MIF in crescentic GN (4.5-fold). In contrast, serum MIF levels were not different between normal patients and any patient group. Immunostaining demonstrated a significant increase in renal MIF expression in proliferative glomerulonephritides that was associated with macrophage and T cell infiltration. There was a significant correlation between the urine MIF concentration and renal MIF expression, but not with serum MIF, indicating a renal origin for the excreted urine MIF. The urine MIF concentration also correlated with the degree of renal dysfunction, histologic damage, and leukocytic infiltration, but not with the amount of proteinuria. In conclusion, this study shows that the urine MIF concentration is significantly increased in proliferative forms of GN and correlates with the degree of renal injury. Urine MIF levels reflect MIF expression within the kidney and may be a useful noninvasive tool for monitoring patients with crescentic GN, particularly in disease exacerbation.

Background. Macrophage accumulation is a prominent feature in many forms of glomerulonephritis. Local proliferation of macrophages within the kidney has been described in human and experimental glomerulonephritis and may have an important role in augmenting the inflammatory response. The current study examined the relationship between local macrophage proliferation and renal expression of macrophage colony-stimulating factor (M-CSF). Methods. A total of 118 renal biopsies of patients with a wide range of glomerulonephridities were examined for M-CSF protein and macrophage proliferation (KP1 + PCNA + cells) by single and double immunohistochemistry staining, respectively. Results. Biopsies of thin membrane disease (TMD) with histologically normal kidney showed M-CSF protein expression by 33% of cortical tubules, while glomerular M-CSF expression was limited to resident macrophages and some podocytes. Glomerular M-CSF expression increased significantly in proliferative forms of glomerulonephritis, with M-CSF staining of infiltrating macrophages, podocytes and some mesangial cells. Segmental areas of strong M-CSF expression, particularly in crescents, co-localized with KP1 + PCNA + proliferating macrophages. There was also an increase in tubular M-CSF expression in most types of glomerulonephritis. Tubular M-CSF staining was strongest in areas of tubular damage and co-localized with KP1 + macrophages, including KP1 + PCNA + proliferating macrophages. Many interstitial macrophages and α-smooth muscle actin-positive myofibroblasts showed strong M-CSF staining. Statistical analysis showed a highly significant correlation between M-CSF expression and local macrophage proliferation in both the glomerulus and tubulointerstitium. Glomerular and tubular M-CSF expression gave a significant correlation with renal dysfunction. Conclusions. Glomerular and tubulointerstitial M-CSF expression is up-regulated in human glomerulonephritis, being most prominent in proliferative forms of disease. This correlated with local macrophage proliferation, suggesting that increased renal M-CSF production plays an important role in regulating local macrophage proliferation in human glomerulonephritis.

We report three cases of women with breast cancer who developed renal impairment following treatment with high-dose ifosfamide. All the women underwent renal biopsy, which demonstrated severe interstitial damage with tubular changes by light and electron microscopy. Although reversible acute tubular dysfunction is well recognised with ifosfamide therapy, the long-term outcome of ifosfamide-induced renal injury remains unclear. The results of the current study suggest that ifosfamide can cause severe irreversible renal tubulointerstitial injury and should be used with caution even when there is initially normal renal function.

Mycosis fungoides (MF) and the leukemic variant, Sezary syndrome (SS) constitute the most common of the cutaneous T cell lymphomas (CTCLs). Subclinical renal involvement with CTCL is not uncommon h...

SUMMARY CD44 is a widely expressed cell surface glycoprotein which is involved in both cell–matrix and cell–cell interactions which regulate a variety of processes, including leucocyte migration and activation. Therefore, we examined the expression of CD44, and its major ligand hyaluronan, during the induction and progression of experimental glomerulonephritis. Antibody staining of normal rat kidney showed constitutive CD44 expression by resident glomerular macrophages, parietal epithelial cells, medullary and occasional cortical tubules. There was a marked increase in CD44 expression over days 1, 7 and 21 of rat crescentic anti-glomerular basement membrane (GBM) glomerulonephritis. Infiltrating monocytes and lymphocytes were CD44+, with ultrastructural studies showing high levels of CD44 expressed on the surface of lymphocytes adherent to activated endothelium. Marked hyaluronan deposition was seen in areas of fibrosis on days 7 and 21, such as glomerular crescents and the periglomerular area. Hyaluronan deposition was accompanied by the presence of many CD44+ cells. Double immunohistochemistry showed that both CD44+ED1+ macrophages and CD44+ myofibroblasts (identified by expression of α-smooth muscle actin) were present in areas of fibrosis. There was also a dramatic increase in cortical tubular CD44 expression, which was most evident in areas of tubular damage. Although tubular epithelial cells expressed CD44 upon both the basolateral and luminal surface, CD44 expression was most prominent within tight junctions, suggesting a role for CD44–CD44 interactions in cell–cell adhesion within the tubule. Analysis of CD44 isoforms by reverse transcriptase-polymerase chain reaction (RT-PCR) showed that the standard form of CD44 predominated in both normal and diseased kidney. However, a series of alternatively spliced CD44 isoforms was also detected, whose expression was markedly increased during disease. At least seven isoforms containing the v6 domain were identified, with the smallest form representing activated T cells. In conclusion, CD44 is constitutively expressed in normal kidney and is dramatically up-regulated in rat anti-GBM disease, suggesting possible roles for the CD44–hyaluronan interaction in leucocyte recruitment, renal fibrosis and tubular cell–matrix and cell–cell interactions during the induction and progression of crescentic glomerulonephritis.

Summary Although CD44 is known to be involved in a wide array of celt to cell and cell to matrix interactions, its role in immune-mediated disease is not well understood. Therefore, using immunogold electron microscopy we have determined the precise !ocalisation of CD44 in the rat lung in experimental Goodpasture’s (GP) syndrome, a model of immune-mediated pulmonary disease. In normal rat lung CD44 was present on the surface of alveolar macrophages but was not detectable on endothelium. In GP syndrome there was strong CD44 expression on all infiltrating inflammatory leucocytes, both adherent to endothelium and within the alveolar spaces and interstitium. However the most striking finding was the progressively strong antibody staining for CD44 on pulmonary endothelium of alveolar capillaries and larger vessels over the 21 days of GP syndrome. In situ hybridisation confirmed that the endothelial CD44 staining was due to local protein synthesis. All epithelial cell surfaces, including bronchial epithelium and type I and 11 alveolar epithelial cells, were negative in normal rat lung and GP syndrome. De novo CD44 expression by endothelial cells during the progression of GP syndrome may contribute to leucocyte recruitment and cell-mediated lung injury.

The nephrotoxicity of polymyxins is a major dose-limiting factor for treatment of infections caused by multidrug-resistant Gram-negative pathogens. The mechanism(s) of polymyxin-induced nephrotoxicity is not clear. This study aimed to investigate polymyxin B-induced apoptosis in kidney proximal tubular cells. Polymyxin B-induced apoptosis in NRK-52E cells was examined by caspase activation, DNA breakage, and translocation of membrane phosphatidylserine using Red-VAD-FMK [Val-Ala-Asp(O-Me) fluoromethyl ketone] staining, a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and double staining with annexin V-propidium iodide (PI). The concentration dependence (50% effective concentration [EC 50 ]) and time course for polymyxin B-induced apoptosis were measured in NRK-52E and HK-2 cells by fluorescence-activated cell sorting (FACS) with annexin V and PI. Polymyxin B-induced apoptosis in NRK-52E cells was confirmed by positive labeling from Red-VAD-FMK staining, TUNEL assay, and annexin V-PI double staining. The EC 50 (95% confidence interval [CI]) of polymyxin B for the NRK-52E cells was 1.05 (0.91 to 1.22) mM and was 0.35 (0.29 to 0.42) mM for HK-2 cells. At lower concentrations of polymyxin B, minimal apoptosis was observed, followed by a sharp rise in the apoptotic index at higher concentrations in both cell lines. After treatment of NRK-52E cells with 2.0 mM polymyxin B, the percentage of apoptotic cells (mean ± standard deviation [SD]) was 10.9% ± 4.69% at 6 h and reached plateau (>80%) at 24 h, whereas treatment with 0.5 mM polymyxin B for 24 h led to 93.6% ± 5.57% of HK-2 cells in apoptosis. Understanding the mechanism of polymyxin B-induced apoptosis will provide important information for discovering less nephrotoxic polymyxin-like lipopeptides.

ICAM-1 and VCAM-1 in human renal allograft rejection. Light microscopy studies have demonstrated heightened ICAM-1 and VCAM-1 expression in renal allograft rejection in experimental animals and in humans, and administration of ICAM-1 blocking antibodies has been shown to prolong graft survival in nonhuman primates. We used a precise ultrastructural immunogold localization technique to identify the exact sites of expression of ICAM-1 and VCAM-1 in both normal human kidney and in renal allograft rejection. In the normal kidney ICAM-1 is moderately strongly expressed in glomeruli, on the endothelium and parietal epithelium and in the interstitium, on the endothelium of peritubular capillaries, arterioles and small arteries, on fibroblast-like interstitial cells and on the brush border of proximal tubules. In contrast, in normal kidney, VCAM-1 expression is restricted to the parietal epithelium and the basolateral surfaces of a few proximal tubule cells. In allograft rejection, although ICAM-1 expression appears to be increased, its pattern of distribution is similar to that seen in the normal kidney. However, VCAM-1 in allograft rejection is widely expressed on the endothelium of peritubular capillaries and arterioles in association with adhesion of mononuclear leukocytes within these vessels. The tubular expression of VCAM-1, although still focal in nature, is increased on the basolateral surfaces in association with lymphocytic infiltration of tubules. Although ICAM-1 expression appears to be up-regulated in renal allograft rejection in a pattern of distribution similar to that seen in the normal kidney, we postulate that it is VCAM-1 which appears on the peritubular capillary endothelium and is strongly focally expressed on the basolateral surfaces of tubules, which is perhaps more strategically placed to be the most relevant adhesion molecule in allograft rejection.

Interleukin-1 is a proinflammatory cytokine produced in glomerulonephritis. Blocking the action of interleukin-1 by the administration of the interleukin-1 receptor antagonist (IL-1ra) has been shown to prevent renal function impairment, reduce glomerular injury, inhibit leukocyte infiltration, and suppress tubulointerstitial damage in experimental antiglomerular basement membrane disease. A key mechanism in the entry of leukocytes into the kidney is the interaction between the interleukin-1 inducible intercellular adhesion molecule-1 (ICAM-1; CD54) and lymphocyte function-associated antigen-1 (CD11a/CD18). Therefore, this study investigated whether the inhibition of this mechanism was the means by which IL-1ra suppressed leukocyte infiltration in rat accelerated antiglomerular basement membrane glomerulonephritis. Disease was induced in two groups of six rats; animals were treated by constant sc infusion of recombinant human IL-1ra or saline from the initiation of disease until being euthanized 14 days later. In saline-treated animals, there was marked up-regulation of ICAM-1 in the glomerulus and interstitium, In which was associated with leukocyte infiltration. In particular, focal accumulation of CD11a+ and CD18+ cells was apparent in areas of tubulointerstitial damage exhibiting intense ICAM-1 expression. IL-1ra treatment partially reduced glomerular ICAM-1 expression and leukocyte infiltration. However, IL-1ra treatment resulted in a dramatic inhibition of interstitial ICAM-1 expression, interstitial leukocyte infiltration, and tubulointerstitial damage. In conclusion, this study has shown that interleukin-1 is a major inducer of ICAM-1 expression within the renal tubulo-interstitium--a process associated with focal leukocyte infiltration and tubulointerstitial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

ICAM-1 directs migration and localization of interstitial leukocytes in experimental glomerulonephritis. Recent studies of rat anti-GBM disease have demonstrated a functional role of the ICAM-1/LFA-1 interaction in the entry of leukocytes into the glomerulus and an association between interstitial ICAM-1 expression, leukocyte infiltration and tubulointerstitial damage. In the current study, we used immunogold ultrastructural techniques to identify ICAM-1/LFA-1 interactions in the initiation of interstitial leukocyte infiltration during the first 24 hours of rat accelerated anti-GBM disease. In normal rats, there was weak constitutive ICAM-1 expression in the interstitium: on the endothelial luminal surface of interstitial capillaries, venules and arterioles, on the entire surface of interstitial fibroblast-like cells and confined to the brush border of proximal tubules. As early as 1.5 hours after injection of anti-GBM serum, there was a marked increase in the intensity of ICAM-1 expression, most notably on capillary endothelium, fibroblast-like cells and brush borders of proximal tubules, particularly in the periglomerular/perihilar areas. Mononuclear leukocytes exhibiting strong surface LFA-1 (CD11a and CD18) expression were seen adherent to the endothelium of interstitial capillaries, with ICAM-1 and LFA-1 antigens present at sites of contact. In addition, mononuclear cells migrating into the interstitium showed areas of close apposition to interstitial fibroblast-like cells, and here ICAM-1 and LFA-1 expression were also prominent at the sites of contact. This is the first study to demonstrate sites of ICAM-1/LFA-1 interaction in mononuclear cell migration and localization in glomerulonephritis. The results suggest that up-regulation of periglomerular/peritubular capillary ICAM-1 expression is important for mononuclear cell entry into the interstitium, while interaction with fibroblast-like cells may facilitate movement and subsequent focal accumulation of mononuclear cells at sites within the interstitium.

Renal primary cilia are sensory antennas required for the maintenance of normal epithelial differentiation and proliferation in the kidney, but they also have a potential role in epithelial differentiation during renal injury and repair. In mice, tubular damage causes an increase in the length of renal cilia, which may modify their sensory sensitivity during repair. Here, we investigated whether the alteration of renal cilium length during renal injury is clinically relevant. Using biopsies of human renal transplants that suffered acute tubular necrosis during transplantation, we compared the length of renal primary cilia with renal function. Serial biopsies showed that acute tubular necrosis resulted in more than a doubling of cilium length throughout the nephron and collecting duct approximately 1 wk after injury. Allografts displayed a trend toward normalization of cilium length in later biopsies, and this correlated with functional recovery. A mouse model of renal ischemia-reperfusion confirmed the increase and subsequent regression of cilium length during renal repair, displaying complete normalization of cilium length within 6 wk of injury. These findings demonstrate that the length of renal cilia is a clinically relevant indicator of renal injury and repair.

Summary We report a case of a 25-year-old man who presented with a large rectal bleed and positive Meckel’s scan followed by surgical excision of a Meckers diverticulum. The diverticulum was lined by gastric body type mucosa showing evidence of active chronic gastritis associated with the presence of Helicobacter pylori organisms, these being identified immunohistochemically with a specific polyclonal antibody. We have reviewed another 21 cases of Meckers diverticula removed at St Vincent’s Hospital between 1984 and 1997: in nine of these cases the diverticulum was lined by ectopic gastric body type mucosa and in one of these there was an active chronic gastritis associated with Helicobacter pylori. There has been considerable controversy regarding both the presence and significance of Helicobacter organisms in Mecket’s diverticula. This is the first study to use immunohistochemistry specifically to identify Helicobacterpyloriwithin two cases of Meckel’s diverticula. Both cases demonstrated an active chronic gastritis present within the gastric body type mucosa, thus suggesting that the organisms play a pathogenic role.

Examined was extracellular-signal regulated kinase (ERK) activation in normal human kidney ( n = 2) and a cohort of glomerulopathies by immunohistochemistry staining for the dual-phosphorylated form of ERK (p-ERK). Cell proliferation was determined by expression of the proliferating cell nuclear antigen (PCNA). In normal human kidney, p-ERK was largely restricted to the cytoplasm of cells of the collecting duct (CD). In glomerulopathies, glomerular ERK activation was highly variable. However, there was colocalization of cell proliferation and ERK activation in the glomerular tuft and crescents. Tubular ERK activation in the different glomerulopathies was confined to the CD in areas with normal architecture. In contrast, ERK activation was prominent in tubules and interstitial cells in areas of tubulointerstitial damage. ERK activation was observed in glomerular and interstitial α-smooth muscle actin–positive myofibroblasts, but few macrophages or T cells showed ERK activation. There was a significant correlation between glomerular p-ERK+ and PCNA+ cells and between tubular p-ERK+ and PCNA+ cells. Glomerular p-ERK+ cells correlated with glomerular cellularity and the percentage of glomeruli with segmental lesions. Tubular p-ERK+ cells correlated with renal dysfunction and interstitial fibrosis and tubular atrophy. In conclusion, activation of the ERK pathway in human glomerulopathies correlates with cell proliferation, histologic lesions, and renal dysfunction. ERK activation may promote renal repair through tubular proliferation while promoting renal fibrosis via proliferation of glomerular and interstitial myofibroblasts.

Activation of the ERK pathway precedes tubular proliferation in the obstructed rat kidney. Background In vitro studies suggest that activation of the extracellular signal-regulated kinase (ERK) pathway plays a critical role in the proliferation of tubular epithelial and myofibroblast-like cells. However, little is known of ERK activation in individual cell types in normal or diseased kidney. The aims of this study were to ( 1 ) localize ERK activation within the kidney, and ( 2 ) examine the relationship between ERK activation and cell proliferation in the injured kidney. Methods Unilateral ureteric obstruction (UUO) was induced in groups of six Wistar rats, which were killed at 30 minutes, 6 hours, and 1, 4, or 7 days after obstruction. Activation of ERK was identified using antibodies specific for the phosphorylated form of ERK (pERK) in Western blots and immunostaining. Proliferating cells were detected using bromodeoxyuridine (BrdU). Results Western blotting showed abundant expression of the two ERK isoforms, ERK-1 and ERK-2, in normal rat kidney. Low levels of activated ERK (pERK-2> pERK-1) were detected in normal rat kidney by Western blotting. Immunostaining showed that ERK activation in normal kidney was largely restricted to collecting ducts in the outer medulla. Within 30 minutes of ureter obstruction, Western blotting showed a sixfold increase in ERK activation followed by a second peak (14-fold increase) on days 4 and 7. The initial peak of ERK activation was localized to medullary collecting ducts and the thick ascending limb of Henle (TALH), whereas the second peak corresponded to a progressive increase in ERK activation in dilated collecting ducts and in interstitial cells in the cortex. Proliferation of tubular epithelial cells closely followed the pattern of ERK activation, being evident first in medullary collecting ducts and TALH on day 1, and then in cortical collecting ducts from day 4. Conclusion This study has identified a discrete pattern of ERK activation in normal rat kidney and an increase in ERK activation following obstruction. The temporal and spatial relationship in which ERK activation preceded tubular cell proliferation suggest that ERK signaling plays a key role in tubular epithelial cell proliferation in the injured kidney.

The p38 mitogen-activated protein kinase (MAPK) pathway is a pro-inflammatory signal transduction pathway. The aim of this study was to examine the role of this pathway in acute renal inflammation. Immunostaining localized components of the p38 MAPK pathway (p38α, p-p38, p-ATF-2) in normal glomeruli, to podocytes, and occasional endothelial cells. This study identified an eightfold increase in glomerular activation of p38 MAPK (phosphorylated p38, p-p38) within 3 h of the induction of rat anti–glomerular basement membrane (GBM) glomerulonephritis and localized p-p38 and p-ATF-2 to infiltrating neutrophils, with increased staining of podocytes and endothelial cells. The relevance of these findings to human acute inflammatory renal disease was determined by examination of biopsy specimens. In patients with post-infectious glomerulonephritis, there was an increased number of positive p-p38 glomerular cells, including p-p38 staining of infiltrating neutrophils, compared with normal human kidney. In rats, administration of a specific p38 MAPK inhibitor, NPC 31145, before induction of anti-GBM disease prevented a loss of renal function and substantially reduced proteinuria. The reduction in renal injury was attributed to a 55% reduction in glomerular neutrophil infiltration and a 68% reduction in platelet accumulation. This was associated with an abrogation of glomerular P-selectin immunostaining and inhibition of glomerular P-selectin gene expression. In summary, this study has localized the components of the p38 MAPK pathway to cells in normal and diseased rat and human kidney and identified a number of important mechanisms by which signaling through the p38 MAPK pathway induces inflammatory renal disease. Blockade of the p38 pathway may be a novel therapeutic strategy for the treatment of acute renal inflammation. E-mail: cosimo.stambe@med.monash.edu.au

A number of well-documented renal lesions have been associated with intravenous drug use. Recently, investigators reported three cases of granulomatous glomerulonephritis in association with intravenous injection of oxycodone suppositories. We report 2 patients with similar glomerular pathology who presented with chronic renal failure. However, we also highlight the widespread tubulointerstitial involvement in this renal lesion. The fibrillar deposits seen within the glomeruli and extensively within tubular basement membranes on electron microscopy do not have the staining characteristics of amyloid and are not associated with immunoglobulin (Ig) deposition. Is this a new form of non-Ig-associated fibrillary glomerulopathy with its pathogenesis linked to some component of the oxycodone suppositories? One of the patients had a history of narcotic addiction but denied intravenous injection of suppositories. In both patients there was progressive deterioration of renal function with 1 patient requiring dialysis within 3 months of initial presentation.

Summary Aims The reported association of glomerular disease with chronic lymphocytic leukaemia (CLL) is rare despite the relative frequency of this type of leukaemia. Hence, we have examined the renal biopsies in three patients with CLL and glomerulonephritis. Methods Renal biopsies were examined by light microscopy, immunofluorescence microscopy and electron microscopy. Results One of two patients with mild impairment of renal function and an active urinary sediment had ultrastructural features of idiopathic type I membranoproliferative glomerulonephritis (MPGN), and the other had features of fibrillary/immunotactoid glomerulonephritis with deposits of IgG and C3. One patient with nephrotic syndrome had characteristic electron microscopic appearances of type III MPGN. In all three there was an association with monoclonal gammopathy. The parameters of glomerular damage improved in association with response to drug treatment of the CLL. Conclusion There is a spectrum of types of MPGN seen in patients with CLL and there appears to be an association with the presence of monoclonal gammopathy. This is the first reported case of type III MPGN in CLL.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays a pathogenic role in experimental crescentic glomerulonephritis (GN). Renal expression of MIF is also upregulated in human GN and correlates with leukocytic infiltration, histologic damage, and renal dysfunction. The study presented here examined whether MIF can be measured in urine and if so, whether the urine MIF concentration reflects the degree of renal injury. Urine and serum MIF was measured by enzyme-linked immunosorbent assay in 10 normal healthy volunteers and in a cohort of 63 patients with GN (2 thin basement membrane disease [TBM], 15 membranous GN, 10 focal segmental glomerular sclerosis, 20 IgA glomerularnephritis, 11 crescentic GN, 10 systemic lupus erythematosis World Health Organization class IV). Renal MIF expression was assessed by immunostaining of biopsy tissue. MIF was detected in urine from normal volunteers (mean +/- SD; 191 +/- 132 pg MIF/micromol creatinine). The urine MIF concentration was unchanged in patients with nonproliferative nephropathies (343 +/- 397 pg MIF/micromol Cr) but was increased 3.4-fold in proliferative nephropathies (645 +/- 527 pg MIF/micromol Cr; P0.05 versus normal and nonproliferative). Stratified analysis showed the greatest increase in urine MIF in crescentic GN (4.5-fold). In contrast, serum MIF levels were not different between normal patients and any patient group. Immunostaining demonstrated a significant increase in renal MIF expression in proliferative glomerulonephritides that was associated with macrophage and T cell infiltration. There was a significant correlation between the urine MIF concentration and renal MIF expression, but not with serum MIF, indicating a renal origin for the excreted urine MIF. The urine MIF concentration also correlated with the degree of renal dysfunction, histologic damage, and leukocytic infiltration, but not with the amount of proteinuria. In conclusion, this study shows that the urine MIF concentration is significantly increased in proliferative forms of GN and correlates with the degree of renal injury. Urine MIF levels reflect MIF expression within the kidney and may be a useful noninvasive tool for monitoring patients with crescentic GN, particularly in disease exacerbation.

Factor H-related protein-5 (FHR-5) is a newly described human plasma protein with structural similarities to human factor H and the four other recently described factor H-related proteins. Unlike the other factor H-related proteins, FHR-5 was initially identified at the protein, rather than complementary DNA, level in studies of glomerular immune deposit composition. To determine the incidence and pattern of detection of FHR-5 in human renal biopsy specimens, a prospective study of 100 consecutive biopsies was performed using anti-FHR-5 monoclonal antibody and indirect immunofluorescence. The pattern of FHR-5 deposition is very similar to that of other complement components, C3 and SC5b-9. It is detected in all complement-containing glomerular immune deposits and has a pattern of extraglomerular deposition similar to that of other complement components. This study shows FHR-5 to be strongly associated with glomerular complement deposition and suggests a role in complement activation or regulation. It may be an important mediator of glomerular disease.

Sir,Vascular endothelial growth factor (VEGF) is a key mediator in the pathogenesis of renal cell carcinoma (RCC). VEGF is up-regulated in clear cell RCC as a result of loss of the von Hippel-Linda...

We report the case of a woman with systemic lupus erythematosus initially manifesting with fever, rash and arthritis, and two years later with Class IV lupus nephritis. Following treatment with cyclophosphamide she developed symptoms and signs of chronic intestinal pseudo-obstruction (CIPO) that was initially thought to be due to a neutropenic enterocolitis. However, persistence of symptoms resulted in segmental resection of the ileum which showed widespread myocyte necrosis and active inflammation within the muscularis propria. A subsequent, more extensive ileocolic resection showed severe diffuse atrophy and fibrosis of the muscularis propria throughout the resected bowel. The absence of mesenteric vasculitis and the clinical response of the CIPO to the immunosupressive regimen of prednisolone and cyclosporin A suggest that the bowel muscle coat changes reflect an intestinal myopathy secondary to systemic lupus erythematosus, and may have an auto-immune etiology.

Transforming growth factor-β regulates tubular epithelial-myofibroblast transdifferentiation in vitro. Background We recently found evidence of tubular epithelial-myofibroblast transdifferentiation (TEMT) during the development of tubulointerstitial fibrosis in the rat remnant kidney. This study investigated the mechanisms that induce TEMT in vitro. Methods The normal rat kidney tubular epithelial cell line (NRK52E) was cultured for six days on plastic or collagen type I-coated plates in the presence or absence of recombinant transforming growth factor-β1 (TGF-β1). Transdifferentiation of tubular cells into myofibroblasts was assessed by electron microscopy and by expression of α-smooth muscle actin (α-SMA) and E-cadherin. Results NRK52E cells cultured on plastic or collagen-coated plates showed a classic cobblestone morphology. Culture in 1 ng/ml TGF-β caused only very minor changes in morphology, but culture in 10 or 50 ng/ml TGF-β1 caused profound changes. This involved hypertrophy, a loss of apical-basal polarity and microvilli, with cells becoming elongated and invasive, the formation of a new front-end back-end polarity, and the appearance of actin microfilaments and dense bodies. These morphological changes were accompanied by phenotypic changes. Double immunohistochemistry staining showed that the addition of TGF-β1 to confluent cell cultures caused a loss of the epithelial marker E-cadherin and de novo expression of α-SMA. An intermediate stage in transdifferentiation could be seen with hypertrophic cells expressing both E-cadherin and α-SMA. De novo α-SMA expression was confirmed by Northern blotting, Western blotting, and flow cytometry. In particular, cells with a transformed morphology showed strong α-SMA immunostaining of characteristic microfilament structures along the cell axis. There was a dose-dependent increase in the percentage of cells expressing α-SMA with increasing concentrations of TGF-β1, which was completely inhibited by the addition of a neutralizing anti–TGF-β1 antibody. Compared with growth on plastic, cell culture on collagen-coated plates showed a threefold increase in the percentage of cells expressing α-SMA in response to TGF-β1. Conclusion TGF-β1 is a key mediator that regulates, in a dose-dependent fashion, transdifferentiation of tubular epithelial cells into α-SMA+ myofibroblasts. This transdifferentiation is markedly enhanced by growth on collagen type I. These findings have identified a novel pathway that may contribute to renal fibrosis associated with overexpression of TGF-β1 within the diseased kidney.

Summary A case is reported of a 75-year-old woman, with a past clinical history of granuloma annulare, who developed groups of papulonodular skin lesions on the trunk and face six weeks after returning from a trip to the Mediterranean. The initial biopsy showed a granulomatous dermatitis which was considered consistent with the sarcoidal variant of granuloma annulare, and the lesions were treated with topical and intralesional steroid. A second biopsy performed four months later revealed large numbers of histiocytes containing diagnostic Leishman bodies. It is not clear whether the first biopsy was from a chronic lesion and the second from an acute lesion, or whether local steroid treatment enhanced proliferation of organisms and made a definitive diagnosis possible on the second biopsy.

The ICAM-1/LFA-1 interaction in glomerular leukocytic accumulation in anti-GBM glomerulonephritis. Recent studies of rat anti-glomerular basement membrane (anti-GBM) disease have demonstrated a functional role for ICAM-1 in the entry of leukocytes into the glomerulus, both in the early polymorphonuclear (PMNL) influx and the more delayed monocyte/macrophage infiltration. In the current study we used immunogold ultrastructural techniques to identify the exact sites of expression of ICAM-1 (CD54) in the glomerulus and the expression of CD11a and CD18 by infiltrating glomerular leukocytes in the first 24 hours of accelerated anti-GBM disease in rats. In normal rats there was constitutive ICAM-1 expression on the luminal surface of the glomerular endothelium and parietal epithelium of Bowman's capsule. In disease ICAM-1 expression was progressively increased over 24 hours on a thickened, reactive glomerular endothelium, being most prominent on endothelium adjacent to the mesangial stalks. Mesangial cells demonstrated surface ICAM-1 expression only in focal areas of superficial mesangiolysis. PMNL, the predominant glomerular inflammatory cell in the first 12 hours of accelerated anti-GBM GN, expressed abundant surface CD18 which was present at the sites of adhesion of the PMNL to the glomerular endothelium. In contrast PMNL expressed only very sparse surface CD11a, suggesting that another β2 integrin, Mac-1, which shares a common β chain with LFA-1 may be the more important PMNL counter receptor for ICAM-1 in the glomerulus. Glomerular monocyte/macrophage infiltration became evident within glomerular capillary loops and the mesangium from 6 to 24 hours. These adherent and migrating leukocytes expressed abundant surface CD11a and moderate CD18 particularly at their sites of adhesion to glomerular endothelium. The presence of both CD11a and CD18 suggest that LFA-1 is the important macrophage counter receptor for ICAM-1 in anti-GBM GN. This is the first study to precisely localize the sites of glomerular ICAM-1 in glomerulonephritis. The results suggest that the up-regulation of glomerular endothelial ICAM-1 plays a role in the early adhesion and localization of glomerular PMNL via the Mac-1 ligand and the later adhesion and migration of macrophages via the β2 integrin LFA-1.

The infiltration and activation of leukocytes within the glomerulus and interstitium play a key role in the initiation and progression of glomerulonephritis. The recent characterization of cellular adhesion molecules has led to the identification of mechanisms by which leukocytes enter the kidney and subsequently interact with renal parenchymal cells. The therapeutic goal of intervening in the infiltration and activation of particular leukocyte populations can be approached by strategies that interrupt binding between specific pairs of adhesion molecules. The ability of anti-ICAM-1 antibody administration to intervene in experiment disease models [29, 39, 58] holds promise for treatment of human glomerulonephritis. Indeed, anti-ICAM-1 antibodies have already proven beneficial in human kidney transplantation [32]. There are many possible alternative therapeutic strategies that do not rely upon mAb therapy. One example is the administration of carbohydrate sialyl-Lewis X, a ligand for P-selectin, which suppresses acute neutrophil-dependent lung injury in rats [54]. Another approach is to block cytokines and other soluble mediators which, amongst other functions, stimulate up-regulation of adhesion molecule expression and leukocyte adhesion. Blockade of PAF action through use of specific antagonists has been shown to reduce injury in various experimental models and part of this effect can be attributed to inhibiting firm adhesion of PMNL to endothelium. Treatment with the IL-1 receptor antagonist can suppress progressive crescentic glomerulonephritis in the rat [43], while anti-IL-8 antibody treatment has been reported to prevent neutrophil-mediated acute glomerular injury in experimental immune complex glomerulonephritis [83]. In summary, the study of adhesion molecules has greatly increased our understanding of pathogenic mechanisms in glomerulonephritis and it holds tremendous potential for development of novel therapies.

The morphological changes in the adrenal cortex and renal juxtaglomerular apparatus have been examined in pregnant sheep subjected to sodium depletion or loading. These changes were similar to those found in non-pregnant sheep in response to sodium depletion or loading, with the additional finding of interstitial edema in the zona glomerulosa of sheep with twin fetuses. As in non-pregnant sheep, sodium depletion resulted in evidence of juxtaglomerular peripolar cell granule release. The major finding was that sodium depletion in sheep with twin fetuses triggered the onset of ovine toxemia or "twin lamb disease".

Twenty-three patients presenting between 1973 and 1987 with the clinical signs of preeclampsia in pregnancy and no apparent past history of hypertension or renal disease underwent renal biopsy intrapartum or in the immediate postpartum period. Three groups were identified using light and electron microscopy, the first with the classical glomerular “endotheliosis” lesion of preeclampsia (55% of cases), the second with endotheliosis coexistent with underlying renal disease (40% of cases), and the third with renal disease alone (5% of cases). The major type of coexisting renal disease was glomerulonephritis. Immunofluorescence studies were not of great value in helping to distinguish cases with endotheliosis alone from those with underlying renal disease.The finding of 40% of cases with endotheliosis in association with preexisting renal disease suggests that the previously unrecognised renal pathology in these patients increases their susceptibility to developing preeclampsia in pregnancy

Regulation of human renal adenocarcinoma cell growth by retinoic acid and its interactions with epidermal growth factor. Retinoic acid (RA) is a natural derivative of vitamin A which regulates the growth and differentiation of epithelia. We have previously proposed that RA participates in compensatory kidney growth and reported that RA inhibits rat mesangial cell growth. This paper describes the effects of RA on a human renal adenocarcinoma cell line (PAD) under different growth conditions, and its interactions with epidermal growth factor (EGF). PAD cells were shown to express RA receptors α and β by Northern blot analysis. In serum free cultures, addition of RA (10-7 M) markedly increased thymidine incorporation by PAD cells (155 ± 7% mean ± se vs. control in 6 separate experiments; P < 0.0001). RA also caused a significant increase in thymidine incorporation by PAD cells under conditions of rapid growth in serum supplemented medium (115 ± 2% vs. control; P < 0.001). RA by itself was unable to reverse contact inhibition of PAD cell growth (NS vs. control), but it synergistically enhanced the mitogenic effect of EGF on confluent monolayers (110 ± 0.6% vs. EGF alone; P < 0.05). Northern blot analysis demonstrated that PAD cells express EGF receptor mRNA, and this was not significantly modified by the addition of RA. Growth arrested (serum starved) PAD cells expressed RAR-α mRNA which was up-regulated eightfold at three hours following the addition of 10% FCS. Thus, our data show that RA is directly mitogenic for serum starved human renal adenocarcinoma cells and that it exerts complex modulation of cell growth in the presence of EGF and serum components.

Tubules are the major site of M-CSF production in experimental kidney disease: Correlation with local macrophage proliferation . Background Local proliferation of macrophages occurs within both the glomerulus and the interstitium in severe forms of human and experimental glomerulonephritis and plays an important role in amplifying renal injury. Macrophage colony-stimulating factor (M-CSF) is thought to be the growth factor driving this local macrophage proliferation. Previous studies have found that glomeruli are the predominant source of M-CSF production. However, this is difficult to reconcile with the prominent macrophage accumulation and proliferation seen in the interstitial compartment in glomerulonephritis. To address this issue, we localized M-CSF expression in rat models of glomerular versus tubulointerstitial injury and examined its relationship to local macrophage proliferation. Methods M-CSF expression (Northern blotting, in situ hybridization, immunostaining, Western blotting) and local macrophage proliferation (double immunostaining) was examined in normal rat kidney on days 1 and 14 of rat anti-glomerular basement membrane (anti-GBM) glomerulonephritis and on day 5 following unilateral ureteric obstruction. Results M-CSF mRNA and protein expression were identified in small numbers of glomerular podocytes, approximately 25% of cortical tubules, and most medullary tubules in normal rat kidney. Northern blotting showed a significant increase in whole kidney M-CSF mRNA in rat anti-GBM glomerulonephritis. Up-regulation of glomerular and, most prominently, tubular M-CSF production was confirmed by three independent methods: in situ hybridization, immunostaining, and Western blotting. The increase in M-CSF expression colocalized with local macrophage proliferation (ED1+PCNA+ cells) in both the glomerulus and tubulointerstitium. On day 5 after ureter ligation, there was a significant increase in tubular M-CSF mRNA and protein expression in the obstructed kidney, with no change in glomerular M-CSF. In parallel with M-CSF expression, macrophage accumulation and proliferation was prominent in the interstitium, but was absent from glomeruli. Conclusions The tubular epithelial cell is the major site of M-CSF production within the injured kidney. Indeed, substantial macrophage accumulation and local proliferation can occur in the tubulointerstitium in the absence of glomerular inflammation. These results suggest that M-CSF production within the kidney, particularly by tubular epithelial cells, plays an important role in regulating local macrophage proliferation in experimental kidney disease.

The ultrastructural changes in various components of the renal juxtaglomerular apparatus have been examined in sheep subjected to sodium depletion or loading. In normal sheep, juxtaglomerular arteriolar myoepithelioid cell granulation was relatively sparse whereas peripolar cell granulation was prominent. Sheep subjected to rapid sodium depletion in response to parotid cannula drainage showed features indicating increased activity of the renin-angiotensin system with a rise in plasma renin concentration, an increase in the juxtaglomerular index and morphological evidence of increased renin granule production in arteriolar myoepithelioid cells. In contrast, in sheep subjected to dietary sodium loading, there was evidence of decreased activity of the renin-angiotensin system with a fall in plasma renin concentration and relatively poor myoepithelioid cell granulation. In sodium depleted sheep, juxtaglomerular peripolar cells showed increased synthetic activity and marked heterogeneity of granule density; in sodium loaded sheep, peripolar cells showed no consistent changes. A major new finding was the detection of exocytotic release of granule material from peripolar cells into the urinary space during sodium depletion, confirming the secretory nature of such cells and supporting the concept that they may play a role in sodium homeostasis.

The renal biopsies of ten women with preeclampsia without other underlying renal disease were examined in detail using light and electron microscopy and immunofluorescence. Characteristic preeclamptic glomerular lesions with endocapillary cell swelling, subendothelial and mesangial deposits, and mesangial interposition were detected in each patient. Juxtaglomerular regions were not prominent and were poorly granulated on light microscopy; ultra-structurally, they showed myoepithelioid cells with sparse renin granulation and considerable heterogeneity of granule size and density in association with relatively meagre granular endoplasmic reticulum and Golgi profiles. These morphologic findings suggest that, in patients with clinical and renal biopsy evidence of preeclampsia, there is no significant stimulation of the renin–angiotensin system.

Ultrastructural changes in renal tubules associated with glomerular bleeding. Renal biopsies from ten patients presenting with macroscopic or heavy microscopic hematuria, shown to be glomerular in origin, were examined by light and electron microscopy. All biopsies showed erythrocytes within tubules by light microscopy and, in five cases, there were morphologic features of acute tubular necrosis. In four biopsies there was clear evidence by electron microscopy of uptake of erythrocytes by renal tubular epithelial cells, associated with some blunting of epithelial microvilli, vacuolar change and increased lysosomal content. Associated with erythrophagocytosis, the subsequent pathway of erythrocyte destruction within renal tubular epithelial cells closely resembled the hemolytic pathway described in macrophages of the reticuloendothelial system.

The cultivable flora was examined in seven plaque samples collected from New Guinea indigenes with active radicular caries. The predominating organisms were streptococci. Actinomyces