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Biomedical subjects

M W Seiler

Publications and source records attributed to M W Seiler.

30 records · Page 2Linked to original sources
PubMed1980

Neurofilaments in the chick embryo during early development. I. Immunofluorescent study with antisera to neurofilament protein.

The time of appearance of neurofilament protein was determined by indirect immunofluorescence in the chick. Immunofluorescence first appeared in 3-day embryos as a peripheral layer on the ventral and lateral surfaces of the spinal cord and hindbrain. Concomitant with a marked thickening of this layer on the ventrolateral surface of the neural tube, neurofibrils were seen emerging from the cord and the myelencephalon. The immunofluorescent layer could be followed rostrally on the surface of the brain up to the mesencephalic flexure. In this location a large bundle of fibrils was observed emerging from the ventral surface of the mesencephalon. The posterior root ganglia and inner layer of the retina were intensely immunofluorescent on day 4. In the following days of development the spinal cord and ganglia assumed a mature configuration. The appearance of the anterior horns on the 6th day was remarkably segmental, the anterior horns being detected in alternate sections in a series of transverse serial section.

Animals↗
PubMed1979

Pathophysiology of Tamm-Horsfall protein.

Tamm-Horsfall protein, a renal glycoprotein present in normal urine, is the primary constituent of urinary casts. Immunoelectron microscopy has shown that this protein is localized selectively along surface membranes of the thick ascending loop of Henle. In this surface membrane site, the unique aggregation and gel formation of Tamm-Horsfall protein in response to increasing concentrations of electrolytes within physiologic ranges may influence the permeability characteristics of this nephron segment. These aggregation characteristics also play a role in pathologic conditions and lead to the prolonged persistence of interstitial Tamm-Horsfall protein deposits in several tubulointerstitial diseases. Recent studies have demonstrated immunologic responses to this protein, including an immune complex tubulointerstitial nephritis in rats mediated by autoantibodies to Tamm-Horsfall protein.

Animals↗
PubMed1977

Pathogenesis of polycation-induced alterations ("fusion") of glomerular epithelium.

Perfusion of rat kidneys with polycations (protamine sulfate, poly-L-lysine), resulted in glomerular epithelial alterations very similar to those observed in proteinuric states, particularly rat aminonucleoside nephrosis. Such changes did not occur after exposure to neutral or anionic macromolecules (poly-DL-alanine, myoglobin, heparin, poly-L-glutamic acid and ovalbumin). Morphigenetic factors in the polycation-induced lesion included retraction and flattening of foot processes, narrowing of filtration slits, formation of occluding junctions between foot processes and cell swelling. The associated suppression of histochemically demonstrable glomerular polyanion suggested that neutralization of cell surface anionic sites was an important factor in the causation of the lesion, which was reversible by reperfusion with heparin. Observations by freeze-fracture confirmed the similarity of the polycation-induced lesion to the epithelial changes in rat aminonucleoside nephrosis. Following exposure to polycations there was also "staining" of anionic sites on epithelial and endothelial cell membranes and glomerular basement membrane. Reperfusion of protamine-treated kidneys with heparin resulted in restoration of previously suppressed colloidal iron staining and the formation of spherical, electron-dense (heparin-protamine) complexes within the glomerular filter.

Animals↗
PubMed1975

Glomerular epithelium: structural alterations induced by polycations.

Perfusion of rat kidneys with the polycation protamine sulfate caused glomerular epithelial alterations resembling those observed in human and experimental nephrotic states. The changes included swelling, blunting, and flattening of epithelial foot processes, were accompanied by decreased stainability of glomerular anionic sites, and were largely reversed by subsequent perfusion with the polyanion heparin.

Animals↗
PubMed1975

Immunochemical characterization of the outer membrane complex of Bacteroides fragilis subspecies fragilis.

The outer membrane of gram-negative bacteria is immunologically the most important structure of the cell because of its accessibility to host defense mechanisms. By electron micrographic studies, it has been shown that Bacteroides fragilis has a cell envelope typical of gram-negative bacteria. The outer memberane of this envelope was found to consist of protein, two polysaccharides bound to lipid in various degrees, and loosely bound lipid. The protein component of the outer membrane had a distinct pattern when studied by polyacrylamide gel electrophoresis. Similar peptide band pattern were seen in all strains of Bacteroides fragilis subspecies fragilis studied, but this pattern was distinct from the pattern found in the outer membranes of other subspecies. The carbohydrates and the protein components were both associated with subspecies-specific immunoprecipitins. We propose that this antigenic complex represents the outer membrane of B. fragilis in its native state and that the immunologically important antigens of this organism are associated with this complex.

Antigens, Bacterial↗
PubMedDate not supplied

Retroperitoneal lymphoma with ribosome lamellae complexes, cytoplasmic projections and desmosome-like junctions: an ultrastructural study.

The ultrastructural finding of ribosome-lamellae complexes (RLC) in 15% of tumor cells in an unusual retroperitoneal lymphoma is reported. Tumor cells had numerous nuclear pockets, cytoplasmic projections, and, not infrequently, desmosomelike attachments. RLC were similar to those previously described in patients with hairy cell leukemia and less often in other leukemia types, with the basic configuration of a hollow cylinder. An intimate association with the rough endoplasmic reticulum was evident. A review of the literature disclosed only other reported lymphoma with similar structures.

Aged↗
PubMedDate not supplied

Sarcomatoid renal cell carcinoma metastatic to the heart: report of a case.

An unusual case of metastatic sarcomatoid renal cell carcinoma is presented. Fifteen months after nephrectomy for a typical clear cell carcinoma, a 63-year-old man presented with bilateral pleural effusions, cardiomegaly, and tamponade. A pericardial biopsy showed an anaplastic spindle cell tumor that was strongly keratin positive and showed desmosomes ultrastructurally. The patient died shortly thereafter, and the autopsy revealed massive tumor infiltration of the heart, pulmonary and adrenal metastases, and tumor nodules at the incision site of his nephrectomy. The differential diagnosis of sarcomatoid renal cell carcinoma is discussed.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Aorticopulmonary paraganglioma (aortic body tumor): report of a case.

A case of aorticopulmonary paraganglioma in a 57-year-old man is described. The tumor comprised nests of uniform cells in a fibrovascular stroma. Electron microscopy revealed abundant neurosecretory granules, and S-100 protein staining demonstrated scattered sustentacular cells at the periphery of typical zellballen. The findings in this case correlated with those of studies on the prognosis for extraadrenal paragangliomas.

Aorta↗
PubMedDate not supplied

Carcinoid tumor of the kidney with morphologic and immunohistochemical profile of a hindgut endocrine tumor: report of a case.

A 54-year-old man underwent a radical nephrectomy for a presumed renal cell carcinoma. The tumor was large, showed areas of cystic degeneration and calcification, and had completely obliterated the normal renal parenchyma. The light microscopic appearance was atypical for renal cell carcinoma, and when electron microscopy revealed innumerable neurosecretory granules a diagnosis of carcinoid tumor was made. The tumor cells were argentaffin- and argyrophil-negative but were chromogranin-, neuron-specific enolase-, and leu-7-positive. When tested with a battery of antibodies against specific polypeptide hormones, the tumor exhibited diffuse pancreatic polypeptide and focal somatostatin immunoreactivity. Our case represents only the 16th case of carcinoid tumor of the kidney to be reported and the first with demonstrated pancreatic polypeptide immunoreactivity. The predominantly trabecular histology, nonreactivity with silver stains, and immunohistochemical profile of this case are common characteristics of hindgut carcinoids, suggesting that, like rectal carcinoids, renal carcinoids are tumors of hindgut endocrine cells.

Antigens, Differentiation↗