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Biomedical subjects

R J Glassock

Publications and source records attributed to R J Glassock.

At least 91 records · Page 5Linked to original sources
PubMed1980

Circulating immune complexes in rats with autologous immune complex nephritis.

Autologous immune complex nephritis (Heymann nephritis) was actively induced in rats by immunization with high (10 mg.) and low (1 mg.) doses of renal tubular epithelial antigen in complete Freund's adjuvant. The development of proteinuria and granular capillary wall deposition of IgG confirmed the previously well described membranous nephropathy which characterizes this experimental disease. Circulating immune complexes were demonstrated by both the fluid phase and solid phase C1q binding assays in both high and low dose experimental groups. The prevalence of such immune complexes was significantly greater in the experimental than in the control groups immunized with adjuvant alone or liver homogenate in adjuvant. The circulating immune complexes bound to C1q were 16 to 23 S in size and were proven to contain a renal tubular antigen. These data, in combination with the previous demonstration of renal tubular antigen and its antibody in kidneys from rats with autologous immune complex nephritis, are consistent with a circulating immune complex pathogenesis of this model of the actively induced autologous immune complex nephritis in rats.

Animals↗
PubMed1980

Antibodies to human glomerular basement membrane: modified methodology for detection in human serum.

A new radioimmunoassay for detection of circulating antibodies to human glomerular basement membrane (GBM) is described. GBM was isolated, purified, and an antigenic component extracted by 8 M urea incubation. The 8 M urea extract was radiolabelled, separated on Sephadex G-150, and employed as GBM antigen for detection of binding in a double antibody radioimmunoassay (RIA). Three groups of sera were studied: (a) 40 normal subjects bound a mean of 0.5% +/- 3.4% (s.d.), (b) 12 patients with glomerulonephritis with non-linear immune deposits in direct immunofluorescent staining of kidneys bound a mean of 0.2% +/- 4.4% (s.d.), (c) 14 patients with Goodpasture's syndrome or glomerulonephritis with linear deposits in direct immunofluorescent staining of kidneys bound a mean of 23% +/- 9.1% (s.d.). Serial dilutions of sera from patients with Goodpasture's syndrome showed a progressive reduction in binding while binding of positive sera was inhibited by increasing quantities of unlabelled GBM. The GBM antigen extracted with 8 M urea is convenient to prepare and conditions for performance of the RIA are reproducible. Hence, this may represent a valuable on-site aid for diagnosis and management of patients with anti-GBM mediated glomerulonephritis.

Adult↗
PubMed1979

IgA antibasement membrane nephritis with pulmonary hemorrhage.

Goodpasture's syndrome has characteristically been described as being mediated by IgG antibodies. We have recently seen a 55-year-old man who developed renal failure and hemoptysis; a renal biopsy showed linear deposits of IgA and C3 involving glomerular and tubular basement membrane. Serologic tests for detecting (IgG) antiglomerular basement membrane antibodies were negative. Elution studies of kidney and lung showed the presence of an IgA antibasement membrane antibody only. The patient's serum contained IgA, but not IgG, antibodies reactive with glomerular and tubular basement membrane of normal human kidney and alveolar basement membrane of normal human lung. Attempts to transfer disease with the patient's IgA antibody to a monkey and to Lewis and Brown-Norway rats were unsuccessful. Immunoglobulin A antibasement membrane antibody must be considered in the design of immunoserologic procedures for the diagnosis of Goodpasture's syndrome.

Animals↗
PubMed1979

Soluble oligovalent antigen-antibody complexes. I. The effect of antigen valence and combining ratio on the composition of fluorescein-carrier anti-fluorescein complexes.

Soluble oligovalent antigen--antibody complexes were prepared and analysed by ultracentrifugation in order to study the effect of the combining ratio, antigen valence and concentration upon the size and molecular composition of the composition of the complexes. Fluorescein (F) conjugates of rabbit serum albumin (RSA) and thyroglobulin (RTg) were combined with high affinity rabbit anti-F antibodies to form soluble complexes. The effect of the combining ratio paralleled findings in precipitating systems in that the largest soluble complexes were found at equimolarity and mild molar antibody excess. Tetravalent antigen formed precipitates at combining ratios near equimolarity, whereas trivalent antigens failed to precipitate at similar concentrations. Complexes prepared near equimolarity were most sensitive to changes in concentration, higher concentrations leading to larger complexes. The Ab/Ag ratios of different-size complexes in the same preparation were remarkably similar. This ratio was dependent on the antibody--antigen combining ratio, was limited by antigen valence and was not affected by concentration differences. The data support the hypothesis that soluble complexes are formed in two steps. First, antigen and antibody combine to form subunits whose Ab/Ag ratio is determined by the combining ratio and antigen valence. These subunits then combine to form larger complexes in a manner analogous to polymerization.

Antibodies↗
PubMed1979

Soluble oligovalent antigen--antibody complexes. II. The effect of various selective forces upon relative stability of isolated complexes.

Soluble oligovalent antigen--antibody complexes were isolated and analysed by ultracentrifugation to assess the effect of several forces upon the composition and stability of soluble complexes. Complexes were prepared with fluorescein (F) conjugates of rabbit serum albumin (RSA) or thyroglobulin (RTg) and high affinity rabbit anti-F antibodies. Isolated complexes containing two antigen molecules (Ag2 complexes) tended to dissociate and form an equilibrium with complexes containing one antigen molecule (Ag1 complexes). This equilibrium was thermolabile, concentration dependent and affected by the original combining ratio and the area in the gradient from which complexes were harvested. Small amounts of free antibody dissociated from soluble complexes also to form a dynamic equilibrium; this equilibrium was much less affected by the above parameters. The data support the concept that complexes grow in size by a process analogous to polymerization of simple subunits and that the driving forces for polymerization are of a lower order of magnitude and more affected by physical variables than the primary reaction between antibody and its antigen.

Antibody Affinity↗
PubMed1978

Acute interstitial nephritis due to methicillin.

Fourteen patients are described with a syndrome of methicillin-induced interstitial nephritis. In all patients severe renal dysfunction developed with an average peak serum creatinine of 8 mg/100 ml. An increased total peripheral eosinophil count was found in all patients. All patients had sterile pyuria and each of nine patients studied by Wright's stain of urine sediment had marked eosinophiluria. These findings are suggestive of methicillin-induced interstitial nephritis, although proteinura was a variable finding in our patients. Eight of 14 patients in our study received prednisone therapy for their interstitial nephritis, and the time lapse between maximal and final base line serum creatinine levels was statistically less in the prednisone-treated compared to the nontreated groups. Clinical manifestations of this syndrome are discussed, and the light and electron microscopic and immunofluorescent findings on renal biospy are described.

Adult↗
PubMed1978

Estimation of relative glomerular capillary surface area in normal and hypertrophic rat kidneys.

The quantity of antiglomerular baSEMent membrane antibodies (antiGBM) binding to the glomeruli of rats 4 hr after i.v. injection of 660 microgram of antiGBM was used as a measure of relative glomerular capillary surface area (Sr). Intact immature and adult rats (N = 27) weighing 46 to 440 g were studied to assess the effect of normal growth on Sr. Young adult rats (N = 36) were studied at 0, 8, 15, and 22 days following uninephrectomy or sham operation to assess the effect of hypertrophic kidney growth on Sr. Bound antiGBM increased from 95 microgram to approximately 350 microgram as rats grew from 46 to 200 g; further growth was associated with no further growth was associated with no further increases in bound antiGBM. In contrast, there was no progressive increase in Sr following uninephrectomy or sham operation despite as 45% increase in kidney weight at 22 days over the comparable kidney in the sham-operated rats (1.32 +/- SEM 0.06 g vs. 0.91 +/- SEM 0.01 g, P less than 0.0001). Thus, increases in GFR during early normal kidney growth parallel anatomic increases in Sr, but increases in GFR with later growth or with compensatory hypertrophy in young adult rats are not accompanied by changes in Sr.

Animals↗
PubMed1978

A clinical and immunopathologic dissection of rapidly progressive glomerulonephritis.

This contribution seeks to illustrate the immunopathogenetic complexities of the syndrome of rapidly progressive glomerulonephritis. As with most of the clinical syndromes of glomerular disease, rapidly progressive glomerulonephritis may be dissected into a number of categories based upon combinations of clinical, morphologic and immunologic observations. It has been demonstrated that such observations have an important bearing on the natural history, prognosis and treatment of this syndrome. Much remains to be learned, particularly with respect to etiological factors, the genesis of extracapillary proliferation and the means of modifying or preventing these diseases.

Antibodies↗
PubMed1978

Permselectivity of the glomerular capillary wall. Facilitated filtration of circulating polycations.

To examine the electrostatic effects of fixed negative charges on the glomerular capillary wall, polydisperse [(3)H]DEAE dextran, a polycationic form of dextran, was infused into 10 Munich-Wistar rats. Fractional clearances of DEAE ranging in radius from 18 to 44A were determined in these rats, together with direct measurements of the forces and flows governing the glomerular filtration rate of water. These results were compared with data previously obtained in Munich-Wistar rats receiving tritiated neutral dextran (D) and polyanionic dextran sulfate (DS). Measured values for the determinants of the glomerular filtration rate of water in rats given DEAE were found to be essentially identical to those in rats given either D or DS. In addition, DEAE was shown to be neither secreted nor reabsorbed. Fractional clearances of polycationic DEAE were increased relative to both D and DS, the increase relative to D being significant for effective molecular radii ranging from 24 to 44A. Fractional DEAE clearances were also measured in a separate group of six Munich-Wistar rats in the early autologous phase of nephrotoxic serum nephritis (NSN). Fractional DEAE clearances in NSN rats were reduced significantly, relative to values measured in normal rats, for effective DEAE radii ranging from 18 to 42A. Moreover, in NSN rats, fixed negative charges on the glomerular capillary wall were greatly reduced, relative to non-NSN rats, as evidenced by a reduction in intensity of colloidal iron staining. Thus, in NSN rats, DEAE clearances were essentially indistinguishable from values obtained with both neutral D and polyanionic DS.

Animals↗
PubMed1977

Detection of circulating immune complexes in patients with glomerulonephritis.

A panel of three immune complex (IC) assays was used in this study to test sera from patients with glomerulonephritis (GN): the Raji cell radioimmune assay (IRCA), the radio-labeled C1q binding assay (IC1qBA), and the microcomplement consumption test (MCT). The sensitivity and specificity of each assay was evaluated in preliminary studies, and the greater sensitivity (5 to 10microgram of aggreagated human gamma-globulin (AHG) per ml of serum) and IgG specificity of the IRCA was apparent. Problems related to the preliminary heat inactivation of test sera, the interaction of C1q with substances other than IC, and the effects of suboptimal storage of test sera were experienced with the MCT and, to a lesser extent the IC1qBA. The individual reactivities of the different assays were exploited by using them in combination. Thus ICs were detected by one or more of the assays in 87% of patients with systemic lupus erythematosus (SLE), 65% of patients with GN associated with other systemic diseases, and 39% of patients with primary GN. ICs were detected more frequently in patients with acute GN than chronic GN, and in patients with low serum C3, C4, and properdin factor B (C3PA) levels.

Acute Disease↗
PubMed1977

Chronic nephritis induced by antibodies reacting with glomerular-bound immune complexes.

The pathogenesis of chronic membranous glomerulonephritis induced in rats by passive immunization with heterologous antibodies to rat renal tubular epithelial (RTE) antigens was investigated. This model is designated as "passive Heymann nephritis" (PHN) in order to contrast it with classical Heymann nephritis induced by active immunization with homologous RTE in adjuvant. A single i.v. injection of heterologous (rabbit) antibody to RTE evoked chronic proteinuria after a latent period of one to three days. The onset of proteinuria was accompanied by the granular deposition of rabbit IgG and rat beta1C globulin along the glomerular capillary wall. Renal isografts developed PHN only when transplanted within the first three days following injection of the heterologous anti-RTE antibodies. The data suggest that the heterologous antibodies form immune complexes with RTE antigens preexisting in the circulation, and these complexes subsequently deposit in the glomerular capillary walls. Chronic proteinuria is then perpetuated by a host reaction to the foreign protein in the deposits (i.e., rabbit IgG), in a fashion analogous to that seen in the autologus phase of nephrotoxic serum nephritis. These studies indicate that continued glomerular deposition of preformed circulating immune complexes may not always be a requisite for the perpetuation of glomerular injury in immune complex disease.

Absorption↗
PubMed1976

Hereditary nephritis, deafness and abnormal thrombopoiesis. Study of a new kindred.

A fourth kindred displaying the triad of hereditary nephritis, deafness and thrombocytopenia with giant platelets is described. Renal involvement, a common cause of death amongst afflicted subjects, appears to have a better prognosis in the affected members of this family. Although the electron microscopic appearance of the megakaryocytes in the present case appears similar to that in previously reported cases, we suggest that the "giant" platelets may result from a degenerative process of megakaryocytes leading to nuclear regression and cytoplasmic fragmentation, rather than the usual blebbing process.

Adolescent↗
PubMed1976

Permselectivity of of the glomerular capillary wall. Studies of experimental glomerulonephritis in the rat using neutral dextran.

Polydisperse [3h] dextran was infused into eight Munich-Wistar rats in the early autologous phase of nephrotoxic serum nephritis (NSN), thereby permitting direct measurements of pressures and flows in surface glomeruli and fractional clearances for dextrans [(U/P) dextran/(U/P) inulin] ranging in radius from 18 to 42 A. Despite glomerular injury, evidenced morphologically and by a marked reduction in the glomerular capillary ultrafiltration coefficient, the glomerular filtration rate remained normal because of a compensating increase in the mean net ultrafiltration pressure. In NSN rats, as in normal controls, inulin was found to permeate the glomerular capillary wall without measurable restriction, and dextrans were shown to be neither secreted nor reabsorbed. For dextran radii of 18, 22, 26, 30, 34, 38, and 42 A, (U/P) dextran/(U/P) inulin in NSN and control rats, respectively, averaged 0.90 vs. 0.99, 0.81 vs. 0.97, 0.63 vs. 0.83, 0.38 vs 0.55, 0.20 vs. 0.30, 0.08 vs. 0.11, and 0.02 vs. 0.03. Using a theory based on macromolecular transport through pores, the results indicate that in NSN rats, effective pore radius is the same as in controls, approximately 50 A. In NSN, however, the ratio of total pore surface area to pore length, a measure of the number of pores, is reduced to approximately 1/3 that of control, probably due to a reduction in capillary surface area. These results suggest that proteinuria in glomerular disease is not due simply to increases in effective pore radius or number of pores, as previously believed. Using a second theoretical approach, based on the Kedem-Katchalsky flux equations, dextran permeability across glomerular capillaries was found to be slightly lower, and reflection coefficient slightly higher in NSN than in control rats.

Animals↗
PubMed1976

Permselectivity of the glomerular capillary wall. Studies of experimental glomerulonephritis in the rat using dextran sulfate.

To determine whether the increased filtration of serum proteins after glomerular injury is the consequence of altered electrostatic properties of the glomerular capillary wall, we measured fractional clearances of the anionic polymer, dextran sulfate, in nine Munich-Wistar rats in the early autologous phase of nephrotoxic serum nephritis (NSN). In agreement with previous studied from this laboratory, whole kidney and single nephron glomerular filtration rates were normal in NSN rats despite histological evidence of glomerular injury, and despite a marked reduction in the glomerular capillary ultrafiltration coefficient to approximately one-third of normal. In the companion study (9), it was shown that in NSN rats the mean fractional clearances of neutral dextrans over the range of effective molecular radii from 18 to 42 A were reduced, compared to normla. In contrast, in the present study the mean fractional clearances for dextran sulfate over the same range of molecular radii were significantly greater than those found previously for normal Munich-Wistar rats. The fractional clearance of dextran sulfate molecules of the same molecular radius as serum albumin (approximately 36 A) was increased markedly, from 0.015 +/- 0.005 (SEM) in nonnephritic controls to 0.24 +/- 0.03 in NSN (P less than 0.001). The sialoprotein content of glomeruli, estimated by the colloidal iron reaction, was reduced in NSN rats as compared to normal controls. It is concluded that the abnormal filtration of anionic serum proteins, such as albumin, seen in glomerulopathies is, at least in part, the consequence of loss of fixed negative charges from the glomerular capillary wall.

Animals↗
PubMed1976

Absence of glomerular renal tubular epithelial antigen in membranous glomerulonephritis.

Renal biopsies from 24 patients with membranous glomerulonephritis were examined by indirect immunofluorescence for the presence of autologous renal tubular epithelial antigen (RTE). Staining of the luminal layer of proximal tubular epithelium was found in all cases, as with normal human kidney, but granular staining along glomerular capillary walls was not observed. The role of RTE in the genesis of human membranous glomerulonephritis has not been confirmed.

Adult↗