Search

Abnormal microalbuminuria in insulin-dependent diabetic subjects (IDDS) is significantly associated with pre-clinical nephropathy. In youth-onset IDDS declining plasma renin activity is significantly associated with improved albumin excretion, while persistently elevated renin activity is associated with continued abnormal microalbuminuria. To determine if these changes are reflected in changes in cell count in the juxtaglomerular body and if biopsy findings correlate with abnormal microalbuminuria, renal tissue of 20 IDDS (Study IDDS) ages 16 to 31 years, evaluated concurrently for plasma renin activity and microalbuminuria, were examined by light microscopy. Biopsy or autopsy specimens from 21 normal subjects and 32 IDDS (Non-Study IDDS), ages 2 to 25, were also examined. Specimens from the majority of prepubertal and all pubertal and postpubertal Non-Study IDDS and all Study IDDS independently of status of microalbuminuria had morphologic abnormalities. Normal or mesangially expanded glomeruli were found in association with expanded juxta-glomerular bodies and increased cell number, or with sclerotic bodies and decreased cell number. Sclerosis of juxtaglomerular bodies occurred independently of glomerular sclerosis. The highest percentage of glomeruli with expanded juxtaglomerular bodies and high cell count was present in specimens of Study IDDS with the most abnormal levels of microalbuminuria. T lymphocytes, noted within juxtaglomerular bodies, were present in specimens of 62% of the 52 Study and Non-Study IDDS. Abnormalities of the juxtaglomerular body are distinctive features of renal pathology in IDDS. T lymphocytes in the endocrine juxtaglomerular body suggest the presence of an autoimmune process. Confirmatory studies are necessary.

Acute serum sickness was induced in New Zealand White (NZW) and in C6 deficient (C6D) rabbits, to compare the histology, immunofluorescence, especially distribution of poly C9 (MAC), and electron microscopic characteristics of the disease in each strain. Glomerulonephritis and albuminuria of comparable extent occurred in 13/17 NZW and 4/8 C6D rabbits. In NZW rabbits with albuminuria an early intense glomerular infiltration by mononuclear cells was associated with focal small fine granular glomerular basement membrane (GBM) deposits of IgG and BSA and more diffuse and larger deposits of C3 and MAC. After the disappearance of monocytes and decrease in mesangial cell proliferation, development of large subepithelial GBM deposits rich in all immune reactants was observed in NZB rabbits. In C6D rabbits with albuminuria a similar monocytic infiltrate occurred, but no association with IgG and C3 GBM immune deposits was noted. No deposits of MAC and no large subepithelial GBM 'humps' were observed in C6D rabbits. We conclude that the exudative (monocytic) phase of glomerular injury and albuminuria in acute serum sickness nephritis are not dependent upon terminal complement components, but the subsequent formation of large subepithelial GBM deposits does not occur in this model in the absence of MAC.

Heparan sulfate proteoglycans (HSPG) are negatively charged constituents of the renal extracellular matrix including the glomerular basement membrane (GBM) and mesangial matrix. Biochemical and functional studies of patients with type-1 insulin dependent diabetes mellitus (IDDM) suggest that alterations of HSPG may occur in diabetic nephropathy. We have utilized a specific cytochemical method and electron microscopy to quantitate the distribution of HSPG in the GBM of 10 normal people and in 16 IDDM patients with a spectrum of clinical and structural changes. Enzyme incubation studies of normal infant kidney demonstrated that heparitinase removed 94% of the stainable anionic sites in the lamina rara externa (LRE) and 77% of the sites in the lamina rara interna (LRI) of the GBM. In contrast, incubation in the enzyme chondroitinase ABC did not reduce the number of sites in the LRE but reduced the number of sites in the LRI by 26%. The HSPG anionic sites in normal subjects were distributed in the LRE as 20.9 +/- 1.3, and in the LRI as 13.1 +/- 2.2 per micron GBM length. Anionic sites were slightly reduced (19.6 +/- 1.3, P less than 0.04) in the LRE of IDDM patients with normal urinary albumin excretion rates (UAE), or microalbuminuria, and were reduced in both the LRE and LRI of IDDM patients with clinical proteinuria (13.1 +/- 2.3, P less than 0.001 and 8.9 +/- 2.1, P less than 0.001, respectively). The number of anionic sites in the LRE and LRI, respectively, correlated with UAE (r = +0.78, P less than 0.001, r = +0.58, P less than 0.02), with GBM thickness (LRE, r = +0.81, P less than 0.001; LRI, r = +0.67, P less than 0.01) and with the volume fraction of mesangium (LRE, r = +0.59, P less than 0.02; LRI, r = +0.58, P less than 0.03). These data confirm earlier biochemical findings of a reduction of HSPG in the GBM in advanced diabetic nephropathy but do not provide evidence for the loss of HSPG in the GBM as a mechanism for early microalbuminuria.

A simple method is presented for selective cell culture of human mesangial cells using explantation of mesangial cell hillocks. Glomeruli which had been incubated with collagenase were explanted on plastic tissue culture flasks. Three to 6 weeks after explantation, a rapidly growing multilayer of elongated mesangial cells was observed to grow over the previously established monolayer of glomerular epithelial cells, ultimately forming multiple nodular foci of mesangial cells or 'mesangial cell hillocks'. By explanting mesangial cell hillocks selectively, pure mesangial cell cultures were easily obtained. When compared with mesangial cells grown in mixed cultures from glomerular explants, the hillock-derived cells were identical in morphology, growth characteristics, cell markers and synthesis of extracellular matrix. This system provides a simple method for the isolation of human mesangial cells in culture.

A boy developed recurrent steroid-responsive nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. The first episode was associated with mild tubulointerstitial rejection on kidney biopsy. Subsequent episodes showed normal histology by light microscopy and epithelial foot process fusion on electron microscopy, consistent with minimal change nephrotic syndrome. Serum analysis for soluble immune response suppressor was negative pre-nephrectomy, positive during each bout of nephrotic syndrome, and negative during each remission. This case represents de novo occurrence of steroid-sensitive minimal change nephrotic syndrome following renal transplantation for congenital nephrotic syndrome. We stress the need for histological examination of the renal allograft to diagnose rejection, recurrent disease, or de novo disease.

A model of posterior urethral valves in fetal lambs was developed in order to evaluate the effect of intrauterine urinary obstruction on the developing kidney. Complete urethral obstruction was induced in five fetal lambs at 43 to 45 days of gestation. Two control fetal lambs underwent sham operations. At full term (140 days), two of the five experimental lambs and both control lambs were available for postmortem examination. Results of gross and histological examination of the control lambs were normal. In contrast, the kidneys of the experimental lambs were markedly asymmetrical in size. Histological examination of the kidneys in experimental lambs showed cystic dilatation of the collecting ducts and occasional cystic dilatation of Bowman's spaces, features compatible with obstruction. Also noted were peripheral cortical cysts and primitive tubules lined with cuboidal epithelium and surrounded by fibromuscular collarettes, characteristic of renal dysplasia. One of the infant lambs had many characteristics of the prune-belly syndrome, including a wrinkled, markedly distended abdomen, deficient abdominal wall musculature, flared chest wall, limb deformities, and undescended testes. These results suggest that early in utero urethral obstruction (at the beginning of the second third of gestation) causes renal dysplasia. The results also support the hypothesis that the prune-belly syndrome results from abdominal distention that occurs early in gestation.

The distribution of IgA, IgG, IgM, C3, and albumin in kidney biopsy specimens from 11 children and adults with recurrent gross and microscopic hematuria and IgA nephropathy and 7 control specimens were evaluated by the direct peroxidase-labeled antibody method and electron microscopy. Granular masses of reaction product (RP), representing IgA, IgG, IgM, and C3, were observed within the mesangial matrix of glomeruli from all patients with IgA nephropathy. Occasional smaller masses of IgA-RP and C3-RP were noted along the peripheral glomerular capillary loops, the tubular basement membranes, and within the interstitial matrix of some patients. Large amounts of IgA-RP and C3-RP were present within the walls of small renal arterioles of several patients. These observations support the concept that immune-complex deposits are involved in the pathogenesis of IgA nephropathy and suggest that vascular deposits may have a more important role in the progression of the disease in some patients.

Recent work suggests that the normal barrier to penetration of the renal glomerular basement membrane by anionic plasma proteins may depend in part on the existence of negatively charged sites within the membrane. We describe an in vitro cytochemical method for the quantitative demonstration of anionic sites in the normal human glomerular basement membrane. In five normal subjects, ranging in age from 10 days to 57 years, the sites were distributed at regular intervals in the lamina rara externa, with a frequency of 23.8 +/- 6.8 sites per 1000-nm length of membrane. A similar distribution was observed in the basement membranes from three normal human fetuses. Ex vivo perfusion of one cadaver kidney revealed a similar distribution of anionic sites. The number of anionic sites in the glomerular basement membranes of five patients with the congenital nephrotic syndrome was reduced to 8.9 +/- 3.7 (P less than 0.001). Prior incubation of sections of normal kidney in purified heparinase resulted in a marked reduction in the number of anionic sites. We conclude that congenital nephrosis results from failure of heparan sulfate--rich anionic sites to develop in the lamina rara externa of the glomerular basement membrane.

Forty-nine patients with systemic lupus erythematosus (SLE) during childhood and adolescence presenting over a period of 17 years were followed during treatment with prednisone and azathioprine. The average period of follow-up was 5.7 years. Detailed analyses of clinical parameters of renal function and sequential changes in glomerular abnormalities by percutaneous renal biopsy are reported. Therapy was directed towards normalizing the results of urinalysis and renal function, eliminating proteinuria and maintaining normal serology (normal serum complement and negative antiDNA titers). The 10 year survival of the entire group was 86 per cent. A survival of 73 per cent and 87 per cent over this interval in patients with diffuse and focal proliferative lupus nephritis, respectively, was achieved. The major cause of mortality in this series was infection. It appears that intensive observation and monitoring of serologic parameters in SLE, along with aggressive steroid and immunosuppressive therapy, lead to a prognosis in SLE more favorable than previously reported.

Utilizing a monoclonal antibody (Poly C9-MA) to a neoantigen of the C9 portion of the membrane attack complex of complement (MAC), immunoelectron (IEM) and immunofluorescent (IF) microscopy were performed on kidney tissue from normal humans and patients with insulin-dependent diabetes mellitus (IDDM) and type II membrano-proliferative glomerulonephritis (MPGN II). Comparative studies were conducted using polyclonal antibodies to human C3, C5, IgG, IgA, and IgM. In normal human tissue, there was a close correlation between increasing chronologic age and the quantity of MAC deposited in the mesangial stalk, along the interstitial aspect of and within tubular basement membranes (TBMs) and in arteriolar walls. IF of kidney tissues from 12 patients with IDDM with varying degrees of mesangial expansion and glomerulosclerosis demonstrated a direct relationship between the degree of tissue damage and the amount of MAC deposited in the mesangium. IEM of three normal and four diabetic specimens revealed reaction product of Poly C9-MA on linear and circular membranous structures within the mesangium, TBMs, and vessel walls, and within the glomerular basement membranes (GBMs) in diabetic subjects. Evidence is presented that these structures, which have been previously described by routine electron microscopy, represent cellular debris in these loci on which Poly C9-MA has been deposited. In MPGN II, Poly C9-MA and C3 were distributed within subepithelial deposits, along either side of the dense deposits (DDs) within the GBMs and TBMs, and around circular masses of DDs within the mesangium.(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral renal disease was produced in rats by left renal perfusion in situ with the aminonucleoside of puromycin or with nephrotoxic serum. The uptake of colloidal carbon by the glomerular mesangium was increased in kidneys perfused with aminonucleoside or nephrotoxic serum compared to contralateral kidneys. The quantities of carbon within the glomerular mesangium remained increased in aminonucleoside perfused kidneys 14 days later. These studies demonstrate that alterations in glomerular mesangial function in aminonucleoside nephrosis and nephrotoxic serum nephritis are related to renal factors rather than differences in host milieu and may be involved in the pathogenesis of the morphologic lesions seen in chronic proteinuria.

This study evaluated a variety of fixatives and methods of tissue preparation for application of the direct peroxidase-labeled antibody technique to rat kidney specimens. Tissue ultrastructure was most satisfactorily preserved and the antigens studied (rabbit IgG, human IgG, and rat Tamm-Horsfall protein (THP) were adequately preserved after brief fixation with 1% glutaraldehyde (15 min), a mixture of paraformaldehyde (1%) and glutaraldehyde (0.05%), or a paraformaldehyde, lysine, periodate fixative. Glycerol substitution was considered an important step which minimized ice crystal artifacts. Freezing and thawing were essential steps that facilitated adequate penetration of labeled antibody to specific antigenic sites. The distribution of injected rabbit IgG (anti-rat glumorular basement membrane (GBM) antibody) was predominately on the lamina rara interna and externa of the GBM. Injected aggregated human IgG was found primarily within the spaces between glomerular mesangial cells. Rabbit anti-rat THP was localized primarily on the infolding membranes of cells of the ascending thick limb of Henle. We suggest that the methods described may have wide application.

The demonstration of bacterial antigens in active pyelonephritis in man has been inconsistent. In this paper we have studied 110 rats with experimental pyelonephritis induced by a single intravenous injection of Streptococcus faecalis. The animals were studied at intervals up to 1 year; bacteremia, urine and renal parenchymal bacterial counts were monitored. In these animals it was observed that bacteriuria and positive bacterial cultures of renal tissue persisted up to 1 year in some rats. Bacteria and their antigenic products in small foci were detected by immunofluorescence in the pyelonephritic lesions. The highly focal distribution of the bacterial antigens in bacteriologically positive tissues of this model suggest the need for careful fixation technics, availability of large tissue specimens and careful control of immunologic factors. These specific requirements to detect bacterial antigens may preclude the practical study of human pyelonephritic kidneys.

Heparan sulfate-proteoglycan (HS-PG) anionic sites located in the glomerular basement membrane (GBM) are thought to contribute to glomerular permselectivity in man. The number and distribution of HS-PG anionic sites in the GBM and mesangial matrix of seven normal human kidneys and three kidneys from children with congenital nephrotic syndrome (CNS) were evaluated by ex vivo perfusion of polyethyleneimine (PEI; Mr 40,000 to 60,000). In the normal kidneys lamina rara externa (LRE) anionic sites (21.8 +/- 2.4 per 1000-nm actual GBM length) were well labeled and similar to those obtained by immersion staining of fixed tissue with Mr 1200 PEI. Lamina rara interna (LRI) anionic site number (22.0 +/- 2.6 per 1000-nm GBM) and appearance were better demonstrated by PEI perfusion than by the immersion technique. PEI perfusion also demonstrated regularly arranged (60 to 120 nm apart) mesangial matrix anionic sites (20- to 30-nm diameter) at 4.09 +/- 0.59 x 10(3) sites per nm2 matrix. PEI perfusion of three kidneys from children with CNS demonstrated decreased (16.3 +/- 1.9 per 1000-nm GBM) LRE anionic sites and normal LRI anionic sites (22.0 +/- 3.5 per 1000-nm GBM). Mesangial volume was increased, and mesangial anionic sites were less frequent (3.24 +/- 0.42 x 10(3) per nm2 matrix) and irregular in size in the children with CNS.(ABSTRACT TRUNCATED AT 250 WORDS)

In heterologous immune complex glomerulonephritis glomerular deposition of immune complexes occurs immediately after an injection with heterologous antibody directed against antigen, derived from the brush border of the tubules. The injected antibody is thought to combine with circulating Fx1A antigen to form immune complexes which subsequently are deposited in the glomeruli. However, perfusion of rat kidneys in absence of this antigen likewise resulted in prompt localization of immune complexes along the glomerular basement membrane. Further, Fx1A antigen was shown to be present in the capillary wall, especially in the filtration slits and on the cell membrane of epithelial cells. From these findings it was concluded that in this model of glomerulonephritis the deposited immune complexes are formed locally instead of being deposited from the circulation. This concept of "fixed antigen" may also be relevant to the pathogenesis of other forms of experimental glomerulonephritis and probably also for human glomerulonephritis.

We examined renal-transplant tissue from 12 diabetic and 28 nondiabetic patients who had had a renal graft for at least two years. In 10 diabetic patients arteriolar hyalinosis lesions developed in the graft. In six these lesions involved both afferent and efferent limbs of glomerular arterioles - a pathological finding virtually diagnostic of diabetes mellitus. In all cases these lesions were present within five years of transplantation. Only three of the 28 nondiabetic patients had hyaline vascular changes (P less than 0.001), which occurred only in rare vessels, did not appear within the first five years after transplantation and did not involve both afferent and efferent arterioles, One diabetic patient had nodular glomerulosclerosis. Thus, the first clearly distinguishable lesion of diabetes to occur with frequency in normal kidneys transplanted into diabetic patients is arteriolar hyalinosis.

A 9-year-old body with sialidosis had nephrotic-range proteinuria. Histological studies demonstrated massive distension of renal cells, particularly glomerular visceral epithelial cells, by cytoplasmic vesicles which contained material reactive with concanavalin A and wheat-germ agglutinin. In addition, some glomeruli exhibited segmental mesangial thickening or glomerulosclerosis. Ultrastructurally, focal detachment of visceral epithelial cells from the underlying glomerular basement membrane was observed. We postulate that glomerular visceral epithelial cell dysfunction may underlie the proteinuria and focal glomerulosclerosis exhibited by this patient. Hyperfiltration, as suggested by the child's elevated creatinine clearances, may be a contributing factor.

Within 20 min after i.v. injection or unilateral renal perfusion of rabbit anti-rat proximal tubular brush border antigens (RARFAXIA) into rats, fluorescence microscopy (FM) demonstrated rabbit IgG (RIgG) in a linear fashion along the endothelial region of the glomerular capillary walls. This finding was confirmed by immuno-electron microscopy (IEM) which revealed the presence of reaction product on the plasma membranes of the endothelial cells. Between 8 h and 26 days following i.v. injection of RARFXIA, granular subepithelial deposits of RIgG were demonstrated by FM and IEM, and the endothelial localization seen at earlier time periods was no longer present. In the later time periods after loss of RIgG from the endothelial region, a second injection of RARFXIA did not result in binding of IgG to this site suggesting loss of the antigen or impairment in antigen-antibody binding affinity. Evidence for depletion of endothelial binding antibody from the circulation was derived from passive transfer experiments, in which sera were harvested from rats either 20 min or 48 h following i.v. injection of RARFXIA-I125. When equivalent doses of these sera were perfused into kidneys of normal rats, minimal glomerular binding was demonstrated with sera obtained at 20 min, but no binding to the capillary wall was observed with sera obtained at 48 h. These observations demonstrate that immediately after the induction of passive Heymann's nephritis (PHN) with the complex polyclonal antibody to FXIA, an antigen-antibody reaction occurs along the endothelial region of the glomerular capillary and that later in the course of the disease in vivo, antibody binding to this site is abrogated. The relationship of this early event to the ultimate development of subepithelial deposits is unknown. This reaction may be a source of immune complexes which migrate through the glomerular basement membrane (GBM) or the early binding of the antibody to an endothelial antigen(s) may result in altered permeability of the glomerular capillary allowing other antibodies to find their putative antigen(s).

Collodial carbon, 70 mg/100 g, was injected into rats which were sacificed for histologic study of the kidneys at intervals of five minutes to seven weeks. Transient thrombocytopenia and albuminuria were observed. Uptake of carbon by the mesangium of glomeruli was maximal at 32 hr and gradually decreased thereafter. Semiquantitative analysis of the distribution of carbon particles within glomeruli revealed a predominately peripheral localization during early time periods, and increased relative concentration of particles within more central zones and in the lacis area at the vascular pole of the glomerulus at two to seven weeks, indicating that one of the mechanisms for clearance of materials from the mesangium was movement of particles in the direction of the lacis area. Sequential electron microscopic studies showed that carbon particles moved through fenestrae in the endothelium covering the mesangium into channels between mesangial cells. Observations at later intervals suggested that carbon eventually reached the vascular pole by being passed on from one mesangial cell to the next. Vasoactive amines or other substances derived from platelets may play an important role in initiating the process of mesangial uptake.

The clinical and histopathologic features of 48 children presenting with the nephrotic syndrome during the first year of life were analyzed. Proteinuria was discovered soon after birth to 3 months of age in 39 infants (congenital nephrotic syndrome), and nine infants had an infantile onset presenting between 4 and 12 months of age. Neither histologic parameters--microglomeruli, epithelial, or mesangial proliferation, focal segmental or global sclerosis, fibrinoid necrosis, or tubular microcysts--nor histologic classification--microcystic disease, mesangial proliferative glomerulonephritis, focal segmental glomerular sclerosis/hyalinosis-predicted the outcome. Rather, age at presentation was found to predict outcome: One of 39 infants with a congenital onset and seven of nine infants with an infantile onset underwent a complete remission (P less than 0.0001).

A nephrotic syndrome caused by immune-complex glomerular disease was diagnosed in a 4-year-old male Great Dane. The syndrome was characterized by proteinuria, hypoproteinemia, hypoalbuminemia, hypercholesterolemia, and subcutaneous edema. Renal biopsy revealed segmental membranous glomerular disease. The edema underwent complete remission 18 days after admission. Two months after admission, there was no clinical or laboratory evidence of glomerular disease. Periodic reevaluation of the dog during the next 2 years revealed recurrence of proteinuria, but no other clinical or laboratory abnormalities. Serial renal biopsies revealed persistence, but no appreciable increase, in the severity of the segmental membranous glomerular disease. The natural course of the nephrotic syndrome and immune-complex glomerular disease has been associated with unpredictable variability. It was concluded that the widespread use of corticosteroid or immunosuppressant therapy in dogs with immune complex glomerular disease should be withheld until the natural course of the disease has been evaluated in a significant number of patients and until the results of well-controlled clinical studies confirm or deny their therapeutic value.

Acute glomerulonephritis is a syndrome characterized by the abrupt onset of hematuria often accompanied by proteinuria, hypertension, edema, and renal dysfunction. Acute glomerulonephritis can be subdivided into primary glomerular disease, postinfectious glomerulonephritis, and glomerulonephritis associated with systemic disease. With few exceptions, the underlying mechanism of acute glomerulonephritis is an immunologic one. To differentiate clinically the specific etiology of the glomerulonephritis, attention must be focused on the presence of signs or symptoms of systemic disease, changes in the environment of the patient, family history of renal disease, and recent history of infectious disease.

The effects of prostacyclin infusion on endotoxin-induced generalized Shwartzman reaction were studied in pregnant rats. Four hours after administration of Escherichia coli endotoxin (0.4 mg) to pregnant rats on the 20th day of gestation, fibrin and platelet thrombi were observed in 72% of the animals. These findings were associated with a decrease in renal blood flow and glomerular filtration rate from 7.0 to 0.7 and 0.8 +/- 0.1 to 2.6 +/- 0.4 and 0.2 +/- 0.8 ml/minute, respectively (p less than 0.0001 and less than 0.05) and a decrease in platelet count (p less than 0.05). The infusion of prostacyclin, at a mean dose of 57 ng/kg/minute prior to and after administration of endotoxin strikingly inhibited the development of fibrin and platelet thrombi in glomerular capillaries (p less than 0.001). Despite hemodynamic changes which were similar to those in control animals, renal blood flow and glomerular filtration rate decreased from 7.2 +/- 0.2 and 0.9 to 2.9 +/- 0.03 and 0.3 +/- 0.1 ml/minute, respectively (p less than 0.001 and less than 0.025). In addition, the mean blood pressure decreased from 118 +/- 3.8 to 86 +/- 3.7 mm Hg (p less than 0.025), whereas the platelet count remained normal. We conclude that prostacyclin infusion prior to endotoxin administration significantly inhibits endotoxin-induced generalized Shwartzman reaction in pregnant rats.

Interstitial deposits of periodic acid-Schiff positive fibrillar material have been detected in a variety of diseases associated with tubulointerstitial pathology. This material has been shown to be Tamm-Horsfall protein by immunofluorescent, immunochemical, and electron microscopic studies. Prospective evaluation of 133 kidneys revealed deposits in 11 per cent. These deposits included medullary cystic disease (50 per cent), obstructive uropathy and vesicoureteral reflux (21 per cent), and tubulointerstitial disease (29 per cent). Tamm-Horsfall protein was also detected in Bowman's space in four cases of obstructive uropathy. It is proposed that these deposits result from severe tubular damage with release of Tamm-Horsfall protein from its normal intracellular and intralumenal locations into the renal interstitium. We speculate that the intersitial deposition of this sequestered protein may result in a continued inflammatory response and progressive renal damage.

Uninephrectomy is known to accelerate the development of both functional and morphological changes seen with experimental diabetic nephropathy in the rat. The present experiments utilized electron and light microscopic morphometric techniques to assess glomerular basement membrane width and the volumes of the total mesangium and its cellular and matrix components of inbred Lewis rats made diabetic at 6 weeks of age and uninephrectomized 9 days later. Immunofluorescent microscopy was used to evaluate IgG and C3 in the mesangium. The reversibility of established diabetic glomerular lesions in uninephrectomized diabetic rats after 7 months of diabetes was studied by performing intraportal transplant of neonatal pancreatic tissue. Renal biopsies were taken 2 months later in transplanted and non-transplanted animals. Islet transplantation lowered plasma glucose to normal levels (29.6 to 7.3 mmol/l) and raised plasma insulin values (6.3 to 53 muU/I). Glomerular basement membrane width in transplanted rats (268 nm) still exceeded the same measure (226 nm) in nondiabetic uninephrectomized rats. In transplanted animals volumes of the mesangium (0.51 x 10(6) micrometers 3) and of its cellular (0.27 x 10(6) micrometers 3) and matrix (0.24 x 10(6) micrometers 3) components remained higher than similar measures in control rats (0.32 x 10(6), 0.17 x 10(6) and 0.15 x 10(6) micrometers 3, respectively). Mesangial IgG in treated animals approached normal, but mesangial C3 remained similar to levels in non-transplanted diabetic control animals. These observations in uninephrectomized-diabetic rats contrast with previous observations in intact diabetic rats in which mesangial volumes and localization of immunoglobulins and complement returned to normal levels following islet transplantation.

The presence of Goodpasture's (GP) antigen in the glomerular basement membrane (GBM) of the kidney was evaluated by indirect immunofluorescence in nine patients with familial nephritis from five kindreds. The GP antigen was not detected in seven males but was present in an affected sister and mother, an unaffected brother, and 13 normal controls. The specificity of this finding in affected males is supported by the persistence of other GBM antigens identified by monoclonal antibodies. The lack of GP antigen in affected males and its persistence in related females with the disease suggests a possible X-linked dominant mode of inheritance. We propose that the absence of GP antigen leads to severe disease in the male, whereas its presence in related females is associated with mild disease.

Cells from human glomeruli explanted in tissue culture were grown and subcultivated up to 12 to 13 times. Light and electron microscopic studies revealed these cells to be morphologically distinct from fibroblasts. By electron microscopy, an extracellular material resembling basal lamina was seen and prominent intracellular microfilaments were evident. Immunofluorescent microscopy demonstrated reactivity of heterologous antiglomerular basement membrane antibody with aggregates of extracellular material. Absorption experiments using antiglomerular basement membrane antibody showed that the extracellular materiial shared some antigenic components with glomerular basement membrane. Antibody to cultured glomerular cells stained the mesangium and glomerular basement membrane of normal human kidney. This antibody was nephrotoxic in monkeys, induced proteinuria with proliferative glomerulonephritis, and localized to the mesangium and glomerular basement membrane of monkey glomeruli. These findings and the presence of prominent intracellular microfilaments (contractile elements) suggest that the glomerular cells may be of mesangial origin.

Intact and uninephrectomized genetically diabetic (db/db) mice (C57BL/KsJ) and their nondiabetic littermates (dm/m) had renal biopsies performed at 6 months of age. Renal tissues were studied by regular light microscopy and by a variety of immunohistochemical techniques. Intact db/db mice had peripheral mesangial thickening as compared to db/m mice. This thickening, predominantly due to increased mesangial matrix material, extended to the glomerular hilum and the extraglomerular mesangium of the juxtaglomerular apparatus. This abnormality was markedly increased an uninephrectomized db/db mice (db/db-UN) compared to intact db/db mice. Db/m-UN animals had slightly greater mesangial thickness than intact db/mice but less than that of db/db mice. Intact db/db mice had increased mesangial IgM staining compared to db/m mice and these differences were magnified by uninephrectomy. The IgM staining, especially in the diabetic mice, involved the peripheral mesangium and the glomerular hilum extending into extraglomerular mesangium and the distal tubule at the level of the macula densa. The tubular staining in the region of the juxtaglomerular apparatus was between the tubular basement membrane and the epithelial cells and between epithelial cells. The distal tubular epithelial cell cytoplasm also showed increased staining for IgM as the tubule coursed away from the glomerulus. These studies amplify the argument that alterations in glomerular hemodynamics influence the rate of development of diabetic glomerular lesions. Further, these diabetic mice appear to represent an important model for the study of mesangial macromolecular processing mechanisms.

Renal insufficiency occurs in at least 1.5% of children with anaphylactoid purpura (AP). We reviewed the records of 16 children who developed end-stage renal disease (ESRD group) secondary to AP and matched them for age, era of onset, renal histology, and clinical severity at onset with 16 children who had AP but whose creatine clearance returned to and remained normal (recovery group). We reviewed creatinine clearances at 1, 3, 5, and 10 years after onset. A creatinine clearance greater than 70 ml/min per 1.73 m2 was present in 50% of the patients in the ESRD group at 3 years and in 25% at 5 years after onset. In contrast, all patients in the recovery group had a creatinine clearance greater than 70 ml/min per 1.73 m2 by 3 years (7 of 16 had a creatinine clearance greater than 125 ml/min per 1.73 m2) and all were normal 95-125 ml/min per 1.73 m2) by 5 years. Thus, the presence of an increased creatinine clearance (greater than 125 ml/min per 1.73 m2) at 3 years predicted recovery, while failure to reach a creatinine clearance of greater than 70 ml/min per 1.73 m2 at 3 years predicted progression to ESRD. There was no evidence of recurrent systemic AP or nephritis in the 14 patients who underwent renal allograft transplantation. We conclude that long-term evaluation of patients over many years is required to identify those who will progress to ESRD from AP and that recurrence of AP in the renal transplant is uncommon.

Immunologically mediated renal diseases include Goodpasture's syndrome, systemic lupus erythematosus, membranoproliferative glomerulonephritis, membranous nephropathy, poststreptococcal glomerulonephritis, IgA-IgG nephropathy and anaphylactoid purpura. In Goodpasture's syndrome, antibodies are directed against the glomerular capillary basement membrane. The other disorders appear to result from circulating immune complexes which deposit in glomerular capillary walls or in the glomerular mesangium. Treatment with steroids and/or immunosuppressives is effective in lupus nephritis; in other diseases, the results are less certain.

Evaluation of pituitary gonadotropins, gonadal steroids, spermatogenesis, and menstrual function was undertaken in 32 patients (19 males and 13 females) treated with cyclophosphamide because of nephrotic syndrome. Patients were treated before, during, or after puberty. Evaluations took place after or in very late puberty. Spermatogenic dysfunction occurred in six of 15 boys who received the entire course before and during puberty and was probably dose related. Menstrual dysfunction did not occur following treatment of six prepubertal or pubertal girls, though only low total doses were used. Therapy after puberty was associated with spermatogenic dysfunction in all four boys, but did not cause menstrual dysfunction in any of seven women. Tentative guidelines are suggested that many minimize gonadal toxicity when cyclophosphamide is used in children with nephrotic syndrome. Factors of particular importance in the interpretation of gonadotropin determinations and of sperm counts in young cyclophosphamide-treated patients are discussed.

Extramembranous glomerulonephritis is an uncommon but distinct pathologic lesion in children. The diagnosis is established by the characteristic light, immunofluorescent, and ultrastructural abnormalities in renal biopsy specimens. This report describes seven of the ten children with this lesion studied in the past 11 years. Emphasis is given to the comparison of four children with idiopathic membranous glomerulonephritis with three others who presented with a nephrotic syndrome but subsequently developed evidence of systemic lupus erythematosus. Two of the latter three children, and three others with SLE and MGN not described in detail, demonstrated deposition of IgA by immunofluorescence along glomerular capillaries. Five of six children with SLE and MGN had microtubular structures in glomerular endothelial cells demonstrable by electron microscopy. These observations suggest that children with MGN require careful and continuing study for evidence of SLE.