Development of renal lesions in dogs after 11/12 reduction of renal mass. Influences of dietary protein intake.

Renal failure was induced in 15 normal Beagle dogs by ligation of approximately 5/6 of the renal arteries of the left kidney and contralateral nephrectomy in order to determine how: (a) 11/12 reduction in total renal mass influences urine protein excretion and renal morphology in dogs, and (b) dietary protein intake influences renal function, urine protein excretion, and renal morphology in canine renal failure. Dogs were fed a reduced protein diet for 12 weeks after induction of renal failure, while compensatory renal hypertrophy developed. Renal function was then evaluated and dogs were distributed into 2 groups with approximately equal degrees of renal dysfunction. One group was fed a high protein diet (42% protein) and a second group was fed moderately restricted protein diets (18% protein). After 8 weeks, renal function, magnitude of proteinuria, and renal morphology were re-evaluated. Inulin clearance increased in all dogs fed the 42% protein diet and 3 of 10 dogs fed the 18% protein diets. Proteinuria was significantly greater in dogs fed the high protein diet than dogs fed the reduced protein diets. Compared with previously nephrectomized contralateral control kidneys, glomerular sclerosis and renal interstitial lesions had developed in all dogs, regardless of severity of renal dysfunction or diet fed. Although reduced dietary protein intake did not prevent development of renal lesions, renal lesions were significantly more severe in the 5 dogs fed the 42% protein diet and 3 dogs fed the 18% protein diets in which inulin clearance increased, than in 7 dogs fed the reduced protein diets in which inulin clearance did not increase.

Use of human amnion for microvascular interpositional grafts.

A major problem associated with vascular grafting employing an artificial graft is the inflammatory response provoked by the graft and subsequent complications of classical acute rejection phenomena when the graft is implanted subcutaneously into human volunteers. The favorable results obtained by a preliminary study of subcutaneous implantation of amnion in our laboratory have led us to a prospective study to determine its value as a vascular graft. Tubed conduits of glutaraldehyde-treated amnion were hand constructed of varying diameters and lengths. They were employed as segmental interpositional grafts in experimentally created femoral and aortic arterial defects in Sprague-Dawley rats. Patency rates varied from 60 to 90 percent, with all grafts showing remarkable reendothelialization within 3 to 4 weeks postoperatively. Morphology, antigenic reaction, blood flow, and patency of the different experimental amnion grafts were evaluated and compared to appropriate controls.

Enzyme immunoassay of anti-glomerular basement membrane antibodies.

An immunoassay has been developed to detect anti-glomerular basement membrane (GBM) antibodies in human sera. Various plating conditions, types of microtiter plates, and the use of biotinylated or peroxidase-labeled secondary antibodies were examined. The described assay is reliable, fast, and convenient. Sera with positive reactivity in anti-GBM nephritis and Goodpasture's syndrome are readily discriminated from sera obtained from normal individuals or patients with a variety of other diseases.

Development and heterogeneity of antigens in the immature nephron. Reactivity with human antiglomerular basement membrane autoantibodies.

Indirect immunofluorescence microscopy was performed with 15 human anti-glomerular basement membrane (GBM) antibodies and mouse monoclonal antibodies to Type IV collagen (MBM4) and renal basement membranes (MBM15) on renal tissue from 6 fetuses (gestational age, 15-23 weeks), 8 infants (age, 1-21 days), and 8 children and adults (ages, 3-27 years). Of the 15 human anti-GBM antibodies that react with GBM in adult glomeruli, only 4 identified antigens in the GBM of fetal and infant glomeruli. In contrast, the monoclonal antibodies bound to basement membranes in the uninduced nephron and the GBM throughout all development stages of the fetal kidney. These studies demonstrate that the reactivity of human autoantibodies with GBM is developmentally and gestationally related--some identifying an antigen(s) in fetal glomeruli with early capillary loop formation and others reacting only with GBM in fully mature kidneys.

Idiopathic immune complex glomerulonephritis in dogs with multisystem involvement.

Renal specimens obtained by biopsy and/or at necropsy from 4 dogs with nephrotic syndrome were studied using light, immunofluorescence, and electron microscopies. The glomerulonephritis observed in these dogs was considered an idiopathic immune complex glomerulonephritis associated with multisystem involvement because causes of glomerulonephritis in these dogs could not be established. Immunoglobulin A was observed in granular deposits in the mesangial and subendothelial regions of the glomeruli. The relationship of the clinical and pathologic features of this disease in dogs to various renal syndromes in human beings are described.

A new glomerular antigen in passive Heymann's nephritis.

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).

Immunofluorescence studies of renal basement membranes in dogs with spontaneous diabetes.

Renal tissue from 12 dogs with spontaneous diabetes and 16 control dogs were studied by light, immunofluorescence, and electron microscopies. Significant linear staining for immunoglobulin G and albumin were observed in the glomerular and tubular basement membranes of dogs with spontaneous diabetes--similar to that observed in human diabetes. On immunohistochemical grounds, it would appear that the dog with spontaneous diabetes is an appropriate model of diabetes in persons.

Kinetics of administered aggregated IgG in rats with passive Heymann's nephritis.

The kinetics of radiolabeled heat-aggregated human IgG (AHIgG125I) were studied in rats with passive Heymann's nephritis (PHN) induced 72 hr previously with decomplemented rabbit antiserum to rat FX1A. Control rats were injected with decomplemented normal rabbit serum (NRS). Following administration of AHIgG125I (40 mg per 100 g of body wt) control and FX1A animals were sacrificed in groups of five each at 2, 4, 8, 16, and 24 hr and kidney, liver, spleen, lung, plasma, and blood cells obtained. 131I-Labeled human serum albumin (HSA131I) was administered prior to sacrifice as a plasma marker. In FX1A rats the following observations were made in comparison with control rats: (1) A decrease in the concentration of AHIgG125I in glomeruli was observed at 2, 4, and 8 hr after administration; (2) a significant increase in clearance reflected by a decrease in the concentration of plasma trichloroacetic acid (TCA)-precipitable radioactivity, and AHIgG125I (greater than 7 S) was present; (3) a significant increase in non-TCA-precipitable radioactivity in plasma and blood cells at most time periods; and (4) decreased concentrations of AHIgG125I in liver and spleen but not lung. The specificity of these observations was supported in separate experiments by the lack of any difference in the plasma levels of TCA-precipitable radioactivity after administration of radiolabeled albumin to FX1A and control rats. Studies in FX1A and control rats revealed no differences in body weight, kidney weight, hematocrit, blood volume, urine output, glomerular filtration rate, renal blood flow, or renal vascular resistance. A slight increase in urinary rat albumin excretion was observed in FX1A rats. The lower values of AHIgG125I observed in plasma, liver, and spleen associated with increased levels of non-TCA-precipitable radioactivity in plasma and blood cells suggest enhanced catabolism of AHIgG125I in FX1A rats, leading to decreased localization within the mesangium.

Absence of Goodpasture's antigen in male patients with familial nephritis.

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.

Glucosylated and normal human of rat albumin do not bind to renal basement membranes of diabetic and control rats.

Hyperglucosylated and normal human and rat albumin were injected intravenously into control and streptozotocin-induced diabetic rats. Binding of injected human albumin to renal basement membranes was not observed by immunofluorescence microscopy in the diabetic or control rats irrespective of the form of injected albumin. However, human albumin was found as tubular droplets in both the control and diabetic rats injected with either form of albumin. Spontaneous binding of endogenous rat albumin was observed in a linear pattern on diabetic rat glomerular basement membranes (GBM), but not in the GBM of control rats. No appreciable differences in the intensity of staining for rat albumin was observed in diabetic rats injected with either glucosylated or normal rat albumin. Similarly, no binding of rat albumin to the GBM was observed in control rats irrespective of the type of albumin injected. These studies demonstrate that binding of albumin to renal basement membranes is not dependent on glucosylation.

Systemic mastocytoma associated with lymposarcoma in an aged cat.

Systemic mastocytoma was diagnosed in a 16 year old cat. Prednisone therapy was initiated but discontinued after 11 months because of development of a duodenal ulcer. Twenty months after the initial diagnosis the cat developed dyspnea, due to enlarged pharyngeal lymph nodes. Euthanasia was performed; systemic mastocytoma and lymphosarcoma were found at necropsy.

A double balloon catheter technique for alloxan diabetogenesis in the dog.

Venous injection of alloxan monohydrate is a standard method to produce a canine model of diabetes. Others have reported mortalities greater than 45 per cent and yields of diabetic dogs of less than 36 per cent with this technique. In this study, a new method for alloxan diabetogenesis is reported upon: alloxan monohydrate is injected intravenously with protection of the renal arteries at the time of injection by a 7F, triple lumen double balloon catheter placed in the abdominal aorta. The balloons are inflated under fluoroscopic control to occlude the renal arteries at the time of injection. Forty-three age-matched beagle dogs were initially injected with 60 milligrams per kilogram of alloxan monohydrate: 26 or 61 per cent became diabetic-defined as persistently doubled fasting serum glucose and glucosuria; ten failed to become diabetic, 23 per cent, and seven died, 16 per cent. The ten initial failures were reinjected with 65 milligrams per kilogram of alloxan monohydrate: six or 60 per cent then became diabetic, three were persistent failures, 30 per cent, and one dog died, 10 per cent. Thus, the over-all yield of diabetic dogs was 74 per cent, with an 18 per cent mortality. Minimal renal damage occurred, as evidenced by creatinine clearance, blood urea nitrogen and renal biopsy studies. These results suggest a significantly improved method--a twofold improvement over standard success rates with a twofold less mortality--of producing diabetic dogs by alloxan injection.

Evaluation of renal biopsy in 197 dogs and cats.

A retrospective study of needle biopsy of the kidney of 163 dogs and 34 cats was performed to evaluate its clinical value and postbiopsy complications. Complications included microscopic hematuria (41 of 53 cases in which urinalyses were performed within 48 hours following the biopsy), gross hematuria (4 dogs), and hydronephrosis (3 of 82 dogs and 1 of 19 cats necropsied). Satisfactory needle biopsy specimens were obtained by use of Franklin-Silverman, Metcoff, and true-cut needles. The necropsy diagnosis matched the biopsy diagnosis in 80 of 82 dogs necropsied and in 17 of 19 cats necropsied.

Multiple cardiac anomalies in a family of Saluki dogs.

Clinical studies of a family of Saluki dogs demonstrated a spectrum of cardiac malformations, which ranged from mild thickening of a pulmonic valve leaflet to a complex condition composed of tricuspid valve insufficiency, pulmonic stenosis, patent ductus arteriosus, and mitral valve insufficiency. All affected dogs had patent ductus arteriosus or ductus diverticulum, which is an incomplete or atypical form of patent ductus arteriosus. The clinical findings varied with the type of cardiac lesion(s) found. Pedigree evaluation suggested a genetic cause, though environmental factors could not be excluded.

Atrial septal defect (sinus venosus type) in a dog.

A 2-year-old Old English Sheepdog had right-side congestive heart failure characterized by pericardial effusion, pleural effusion, ascites, and increased pulmonary wedge pressure. A diagnosis of atrial septal defect was made by means of cardiac catheterization and angiography. Surgical correction initially was deferred because of pulmonary hypertension. However, when congestive heart failure could not be managed adequately, surgical correction was attempted. Postsurgically, thrombocytopenia developed and that led to bleeding, oliguira, and pulmonary edema. The bleeding was controlled by whole blood transfusion, but the oliguria and pulmonary edema were not resolved, even with intensive diuretic therapy. The dog died 24 hours after surgery.