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Biomedical subjects

S S Iskandar

Publications and source records attributed to S S Iskandar.

33 records · Page 2Linked to original sources

Modification of stroke susceptibility by genotype-dependent maternal influences.

The influence of the prenatal and postnatal maternal environment on stroke susceptibility was evaluated by reciprocally crossing the spontaneously hypertensive (SHR) and the Dahl salt-sensitive (SS/Jr) inbred rat strains to produce reciprocal F1 hybrids that were nurtured, respectively, during prenatal and postnatal life by SHR or SS/Jr mothers. Following placement on a high-salt diet containing 8% NaCl at 35 days of age, F1 rats reared by SHR mothers had shorter survival times and were more likely to die with cerebral hemorrhage than F1s reared by SS/Jrs. Across reciprocal F1 female groups, enhanced susceptibility to stroke was associated with greater elevations of systolic blood pressure, but this association was not seen across reciprocal F1 male groups. There was also an association between blood pressure and stroke within each F1/gender subgroup: Rats eventually suffering strokes developed higher blood pressure after placement on the high-salt diet than rats that did not suffer stroke. Lower day 35 body weights (before exposure to the high-salt diet) were associated with greater likelihood of stroke both across the reciprocal F1 groups, and within three of the four F1/gender subgroups. The differences in stroke susceptibility between the reciprocal F1 groupings may be due to systematic differences in the prenatal and/or postnatal environments of SHR and SS/Jr mothers and may be mediated by variations in the nutritive capacity of the two inbred mothers.

Animals↗

Mesangiolytic glomerulopathy in a bone marrow allograft recipient.

A boy with null-cell leukemia received a bone marrow allograft after preparation with chemotherapy and total body irradiation. Cyclosporine A was not administered following transplantation. Renal biopsy performed 6 months after transplantation because of unexplained deterioration of renal function revealed diffuse mesangiolysis and glomerular sclerosis. The significance of this finding is discussed with reference to similar, recently reported cases.

Bone Marrow Transplantation↗

Enzyme histochemistry of monocytes/macrophages: a study in a murine model of immune complex-mediated glomerulonephritis.

In a model of immune complex glomerulonephritis in BALB/c mice, cells of monocyte/macrophage lineage (M phi), identifiable by electron microscopy, infiltrate the glomerulus. In spite of this, no unequivocal nonspecific esterase activity can be demonstrated histochemically in the glomeruli. On the other hand, many mononuclear cells with strong acid phosphatase activity are consistently present. This observation is in line with other studies that have demonstrated the heterogeneity of enzyme profiles in different M phi populations. Despite the wide acceptance of nonspecific esterases as markers for M phi, the present study indicates that exclusive reliance on a single marker in investigating the participation of M phi in a pathological process can lead to erroneous conclusions. Use of multiple markers and preferably multiple investigative modalities is recommended.

Animals↗

Immune complex acute necrotizing glomerulonephritis with progression to diffuse glomerulosclerosis. A murine model.

Male BALB/c mice given daily intraperitoneal injections of 4 mg of horse-spleen apoferritin develop, in the majority of cases, a proliferative and necrotizing glomerulonephritis with leukocytic infiltration and extensive intraglomerular thrombosis within 10 to 14 days, as previously reported. We now show that if injection of the antigen is discontinued, surviving animals develop extensive glomerulosclerosis (GS). Ten of 13 mice treated as indicated above and sacrificed 4 months after the last horse-spleen apoferritin injection developed segmental GS involving over 40% of their glomeruli. Tubulointerstitial damage of proportionate severity also developed. Ultrastructurally, pronounced mesangial expansion due to matrix deposition obliterated the glomerular architecture. We offer this as a reproducible model of immune complex-mediated GS particularly suited to the study of cellular interactions involved in the pathogenesis of GS.

Animals↗

Cardiomyopathy associated with the acquired immune deficiency syndrome.

Three cases of congestive cardiomyopathy complicating the acquired immune deficiency syndrome (AIDS) are reported. In one case, acute cardiac decompensation resulted in prolonged but ultimately reversible cardiogenic shock. In the second case, clinical signs of cardiac disease were precipitated by acute renal failure and fluid overload. In the third, congestive heart failure developed spontaneously and responded promptly to administration of diuretics but the patient died suddenly, apparently due to an arrhythmia. The etiology of cardiomyopathy in AIDS is unclear and the manifestations of cardiomyopathy in this setting range from subclinical to life threatening.

Acquired Immunodeficiency Syndrome↗

Nephropathy induced in a nephritis-resistant inbred mouse strain with the use of a cationized antigen.

C3H/HeN mice produce small amounts of antibody when challenged daily with 4 mg horse spleen apoferritin and fail to develop significant renal histologic and immunohistologic lesions. When the same dose of antigen is given in cationized form, glomerular deposits of both antigen and IgG, often accompanied by C3, are uniformly found in all animals. Thus it appears that cationized antigens can induce the formation of potentially damaging immune complexes in low-antibody-producing individuals that are not ordinarily susceptible to this kind of immune injury.

Animals↗

Primary cerebral lymphoma with glomerular renal involvement.

We report a case of primary cerebral lymphoma metastasizing to the kidney with exclusive involvement of the glomeruli. We discuss the possible explanations of this unusual phenomenon, and present some of the unusual clinical features of the case. Nephropathologists interpreting glomerular hypercellularity should always consider metastatic neoplasms as a possible, though rare, cause.

Biopsy↗

Pathologic differentiation between lupus and nonlupus membranous glomerulopathy.

The following clinical and pathologic features were evaluated in 170 patients with electron microscopically documented membranous glomerulopathy: age, sex, race, American Rheumatism Association lupus criteria, serum ANA, serum complement, glomerular hypercellularity, stage of subepithelial dense deposits, endothelial tubuloreticular inclusions, tubular basement membrane deposits, tissue ANA, glomerular deposition of IgG, IgM, IgA, C3, C4, and Clq. At the time of biopsy 148 patients had no clinical evidence for lupus, and 22 had a clinical diagnosis of lupus. Six additional patients eventually developed overt lupus after an average of 12 months. Incidences of serologic and pathologic features in lupus as compared with nonlupus membranous glomerulopathy were determined. These data were used to calculate sensitivity, specificity, positive and negative predictive values, and overall efficiency of each parameter in differentiating between lupus and nonlupus membranous glomerulopathy. In general, serologic, morphologic and immunohistopathologic features are more accurate at ruling out lupus than making the diagnosis of lupus. However, a number of features are significantly more frequent in lupus membranous glomerulopathy. Therefore, identification of these features, especially more than one, warrants a high suspicion of lupus rather than nonlupus membranous glomerulopathy even in patients without clinically overt systemic lupus erythematosus. The positive/negative predictive values of some of the pathologic features studied are as follows: mesangial dense deposits 63/99, subendothelial dense deposits 77/93, tubuloreticular inclusions 61/96, intense C1q deposition 47/95, tubular basement membrane deposits 100/87, and glomerular hypercelularity 26/86.

Antibodies, Antinuclear↗

Influence of antibody avidity on glomerular immune complex localization.

Immune-complex-mediated glomerulonephritis (IC-GN) was induced with daily intraperitoneal injections of horse apoferritin (HAF) for varying intervals in Swiss albino and BALB/c mice. Anti-HAF antibody avidity in plasma pools from mice with predominantly mesangial immune deposits was compared with avidity in plasma pools from mice with predominantly capillary wall deposits. Plasma from Swiss mice having predominantly mesangial deposits after 7 or 14 days of HAF had higher avidities than plasma from Swiss mice with predominantly capillary wall deposits after 14 days or more than 28 days of HAF. Plasma from BALB/c mice with exclusively mesangial deposits after 7 days of HAF had higher avidity than plasma from BALB/c mice with predominantly capillary wall deposits after 14 or more days of HAF. Therefore, there was a correlation between glomerular site of immune deposition and avidity of circulating anti-HAF antibodies, with higher avidity antibodies associated with mesangial immune deposits and lower avidity antibodies with capillary wall deposits.

Animals↗

Interaction of antigen load and antibody response in determining heterologous protein nephritogenicity in inbred mice.

Genetically disparate inbred mouse strains mounting quantitatively different immune responses to a potentially nephritogenic heterologous protein had varied development of glomerulonephritis (GN) dependent upon the interaction between level of antibody response and antigen dose. High responder BALB/c mice given high doses of horse apoferritin developed a severe necrotizing GN. BALB/c mice given low dose horse apoferritin developed less severe GN, or when antibodies were in extreme excess, no GN. Low responder C3H mice given high dose horse apoferritin were in extreme antigen excess and developed no GN. C3H mice given low dose horse apoferritin developed a glomerulopathy characterized by capillary loop immune deposits. Interstrain differences in immune clearance and avidity did not account for this varied nephritogenicity, although avidity did relate to glomerular site of immune deposits in the BALB/c model. In the models under consideration susceptibility to heterologous antigen-induced glomerular injury was a function of the magnitudes of both the antibody response and the antigenic challenge.

Animals↗

Interstrain variations in nephritogenicity of heterologous protein in mice.

Swiss albino, BALB/c, and eight substrains of C3H mice were given daily intraperitoneal injections of horse apoferritin (HAF) for up to 56 days. At varying intervals, renal tissue was examined by light, immunofluorescence, and electron microscopy. Swiss mice developed proliferative glomerulonephritis after 7 to 14 days of HAF, and 45 per cent progressed to severe crescentic glomerulonephritis after from 21 to 56 days of HAF. In Swiss mice, glomerular immune deposits evolved from predominantly IgM mesangial deposits at 7 days to mesangial IgG at 14 days to capillary wall IgG after 21 or more days of HAF injections. BALB/c mice given identical HAF doses never developed severe crescentic glomerulonephritis but rather an extensive global necrotizing glomerulonephritis most prevalent after from 9 to 18 days of HAF. The distinct evolution of glomerular immune deposits observed in Swiss mice was less clear-cut in BALB/c mice, with greater persistence of mesangial deposits and IgM over time. Only 11 per cent of C3H mice (confined to two substrains) developed glomerular lesions by light microscopy after 2 to 3 weeks of HAF administration. No C3H/HeN mice developed glomerulonephritis even after up to 47 days of HAF injection. From 7 days on, 45 per cent of HAF-injected C3H mice had low level IgM mesangial immune deposits but did not manifest the evolution from mesangial to capillary deposition observed in BALB/c and Swiss albino mice. F1 hybrid and congenic mice carrying BALB/c H-2 genetic information developed glomerular lesions similar to those produced in BALB/c mice. These data (1) indicate an interrelated morphologic and immunohistologic evolution of heterologous protein induced glomerular lesions in mice, (2) demonstrate morphologic and immunohistologic differences in glomerular lesions development between genetically disparate mouse strains given identical antigen exposures, and (3) support the genetic control of heterologous protein-induced glomerulonephritis and suggest a role for the major histocompatibility region in this genetic regulation.

Animals↗