Fluorescent staining of nuclei and amyloid substance. Two useful properties of p-phenylenediamine.

Mounting immunofluorescent slides in an oxidized solution of p-phenylenediamine in 90% glycerol, resulted in brown fluorescent staining of nuclei. This contrasts well with the fluorescence of fluorescein and rhodamine conjugates and facilitates excellent morphological localization of antigens. The antifading effect of p-phenylenediamine is maintained in this oxidized solution. In addition, amyloid substance gives a bright yellow-orange fluorescence with this medium. This method of staining is more sensitive and less time consuming than the usual methods for amyloid. Alternative techniques to keep the antifading effect without either nuclear or amyloid counterstain (for identification of nuclear antigens), or to show up amyloid deposits without nuclear counterstain (for small amyloid deposits) are described.

Antitubular basement membrane antibodies in renal allograft rejection.

In a patient with an episode of acute renal allograft rejection, antibodies to tubular basement membranes (TBM) were noted by direct immunofluorescence in a renal biopsy and by indirect immunofluorescence in the serum. The serum antibodies decreased gradually and became undetectable 3 months after the rejected kidney was removed. Anti-RBM antibodies eluted from the rejected kidney were capable of binding in vitro to TBM but not to glomerular basement membranes (GBM) in 39 of 40 human kidneys and various animal kidneys. The specificity was confirmed by blocking studies showing inhibition with ultrasonicated human TBM but not with GBM preparations. Passive transfer experiments showed that anti-TBM antibodies were able to bind in vivo to normal rabbit kidneys, although they could not elicit an inflammatory response. The possible mechanisms of production of anti-TBM antibodies and their potential significance in graft loss are discussed.

Renin storage and cell differentiation in juxtaglomerular cell tumors: an immunohistochemical and ultrastructural study of three cases.

Three renin-secreting juxtaglomerular cell tumors were studied by ultrastructural and immunocytochemical methods. Both active and inactive renins were identified in tumor extracts. By immunofluorescence and the peroxidase-antiperoxidase (PAP) method with antirenin antiserum, immunolabeling was intracytoplasmic and irregularly distributed throughout the tumor tissue. Electron microscopic examination revealed various types of secretory granules, including atypical giant crystalloid protogranules in one case, and the postembedding PAP procedure showed labeling of all types of granules. Acid phosphatase staining was observed within secretory granules and autophagic vacuoles. The process of renin storage and release is discussed. The presence in one case of a neural component and a distal tubular structure supports the view of a hamartomatous lesion.

Solitary meningeal plasmacytoma: Report of a case with electron microscopic and immunohistologic observations.

An unusual case of solitary extraskeletal plasmacytoma (SEP) arising from the meninges of the anterior fossa in a 58-year-old woman is presented. Despite an apparently complete surgical excision and 5000 rads to the tumor area given postoperatively, a recurrence ensued 5 years later. During the 5 years of clinical observation, repeated serum electrophoresis and immunoelectrophoresis, bone surveys, and bone marrow aspirations have ruled out the presence of underlying multiple myeloma. Immunofluorescence studies of the recurrent tumor showed the neoplastic cells to be producing a monoclonal immunoglobulin (IgA, kappa). Ultrastructural examination showed neoplastic plasma cells with marked nucleocytoplasmic asynchrony, frequent cytoplasmic electron-dense bodies, and rough endoplasmic reticulum dilated and filled with with electron-dense material. A critical evaluation of the eight cases of intracranial SEP published in the literature revealed that only three are well-documented examples of this tumor.

Cysts of the tunica albuginea. Report of 4 cases and review of the literature.

Four cases of benign testicular cysts arising from the tunica albuginea are reported. A review of the literature yielded only 4 more instances of such lesions. Clinically, these cysts may be manifested as a tumor or painful swelling, or are discovered incidentally. In 3 cases a diagnosis of testicular carcinoma was entertained and high inguinal orchiectomies were done. The possibility of a conservative surgical approach, as followed in 1 case, is discussed. These cysts appear in the anterior and lateral aspects of the testis, show ample connection to the albuginea and are lined by a cuboidal epithelium. Gland-like inclusion were found in the fibrous cystic walls and in the albuginea. The histogenesis of these lesions is discussed and evidence for a possible origin in mesothelial rests trapped during development is presented. The differential diagnosis of cystic lesion of the tests is reviewd briefly.

Hepatic fibrinogen deposits in pre-eclampsia. Immunofluorescent evidence.

To investigate if fibrin (or fibrinogen), immunoglobulins and complement were present in the liver of patients with toxemia of pregnancy, we performed immunofluorescence studies on needle biopsies of pre-eclamptic women. Fibrin (or fibrinogen) outlining the hepatic sinusoids was found in all 12 cases; in two of them there were also large nodular deposits of fibrin (or fibrinogen) and to a lesser extent of IgG, IgM and C3 in areas of necrosis. Immunofluorescence study of 13 control liver biopsies, six from pregnant women, was negative. Our findings suggest that the factors involved in glomerular and hepatic injury are similar. To explain the predominant involvement of liver and kidney, we propose that in these organs, the vasospasm characteristic of toxemia is more severe; this enhanced severity, in the presence of a systemic yet mild blood hypercoagulability, would create adequate local conditions for the precipitation of fibrin-fibrinogen.

Papillary renal cell carcinoma: a clinical, radiologic, and pathologic study of 34 cases.

Papillary renal cell carcinoma (RCC) is known by its tendency to avascularity by angiography; however, data concerning its clinicopathologic spectrum and prognosis are not available. In a review of 224 renal cell carcinomas accesioned in our files, 34 were found to be papillary and 190 of other histologic types. A comparative analysis of these two gropus revealed marked differences. The majority of papillary tumors (85.3%) were in pathologic stage I, whereas more than half of the nonpapillary tumors had extended beyond the limits of the kidney. Follow-up data revealed that the survival for papillary RCC was significantly higher than that for nonpapillary tumors. This difference held true even when tumors in the same pathologic stage were compared. Many papillary tumors, particularly those with a favorable course, were massively necrotic, densely infiltrated by macrophages, or both. In view of these findings, the possibility that host mechanisms are involved in destruction and confinement of the tumor is discussed. Examination of kidney tissue distant from the tumor disclosed, in some cases, atypical hyperplastic changes of collecting tubules; this raises the possibility that some papillary tumors arise from distal tubular epithelium. Hypo- or avascularity was present in all papillary RCC's studied by angiography.

Clinical comparison between vascular and avascular renal cell carcinoma.

Of 72 patients with renal cell carcinoma 19 were found to have an angiographic avascular neoplasm. These avascular tumors have a lower incidence of vein and capsule invasion than vascular tumors. Among these avascular cancers papillary adenocarcinoma was the predominant histologic pattern. Patients with papillary tumors seem to have a lower clinical stage and increased survival rate than patients with non-papillary tumors.

Idiopathic microscopic polyarteritis nodosa: ultrastructural observations on the renal vascular and glomerular lesions.

Although the glomerulonephritis (GN) and renal vasculitis in polyarteritis nodosa (PAN) are generally considered to be immune-mediated, the pathogenesis of the renal injury and the role of immune complex (IC) deposition are unclear. To better define the nature of the glomerular and vascular injury in PAN, we performed a detailed ultrastructural study of 27 renal biopsies from 20 patients with histologically confirmed PAN of the microscopic or overlap (microscopic/macroscopic) type. A total of 48 arteries and arterioles were studied ultrastructurally, including 20 vessels with recognizable vasculitis in 1 micron-thick survey sections. By immunofluorescence, glomerular and vascular immunoglobulin deposits were generally scanty, primarily located in areas of necrosis or sclerosis. Fibrinogen, C3 and C1 were more commonly detected, often in the absence of demonstrable immunoglobulin. By electron microscopy, discrete electron-dense deposits of probable immune-type were found in the glomeruli of five initial biopsies. No electron-dense deposits were identified in any of the arteries or arterioles studied. In both glomeruli and vessels, endothelial injury and subendothelial fibrin deposition were the earliest detectable ultrastructural changes. The pathogenetic implications of these findings are discussed.

IgG Fc membrane receptor on normal human glomerular visceral epithelial cells.

This study demonstrates that human glomerular epithelial cells are able to bind heat aggregated immunoglobulins and antigen-antibody complexes. This has been observed on kidney cryostat sections, on whole glomeruli and on cultured visceral epithelial cells. Binding depends on the presence of the Fc portion of IgG and occurs in the absence of complement, showing that the IgG Fc receptor is different from the C3b receptor. The use of heat aggregated anti-peroxidase IgG and of peroxidase anti-peroxidase complexes allowed us to demonstrate, at the ultrastructural level, that the binding of the reagents at the plasma membrane was followed by their internalization within coated pits of vesicles. These observations strongly suggest that glomerular visceral epithelial cells are capable of receptor mediated endocytosis. The role of this process in glomerular diseases remains to be established.

Phagocytosis of heat-aggregated immunoglobulins by mesangial cells: an immunoperoxidase and acid phosphatase study.

It has been demonstrated previously that mesangial cells (MC) phagocytose particulate material and nonimmune proteins, but that cells are able to engulf aggregated immunoglobulins (Igs) has not been proven so far. To investigate this cell function, heat-aggregated antiperoxidase (HRP) Igs were injected intravenously into Lewis rats. Sequential immunoelectron microscopic studies revealed that the injected material accumulates progressively in the extracellular compartment from 10 minutes to 5 hours and disappear afterward. This disappearance was related in part to the incorporation of aggregated anti-HRP Igs within phagosomes and phagolysosomes by MC. Quantitation of the phagocytic process showed that it starts as early as 10 minutes after injection and reaches its peak at 2.5 hours. Endocytosis seems to be associated with the sequestration of injected Igs within large cytoplasmic invaginations and with micropinocytosis. To further support these observations, ultrastructural cytochemistry for acid phosphatase activity was performed. Quantitative studies showed that the number of acid phosphatase-labeled lysosomes in MC was up to 7-fold greater in rats receiving aggregated anti-HRP Igs than in noninjected ones. In conclusion, our combined immunoperoxidase and acid phosphatase studies show that MC possess a vacuolar (lysosomal) apparatus capable of handling heat-aggregated Igs. Whether these cells are also operational in the disposal of soluble immune complexes in spontaneous and experimental conditions remains to be proven. In addition, observations suggesting the drainage of macromolecules from mesangium to the juxtaglomerular apparatus and from mesangium to the urinary space are presented.

Cavernous hemangioma of the kidney.

Three patients with cavernous hemangiomas of the kidney all presented with hematuria. In each there was found a poorly defined renal medullary mass with displacement of the calyces and renal vessels and paradoxical hypovascularity of the mass. This rare, benign tumor of the kidney should be considered in the presence of this characteristic clinical picture.