Corticolipotropin immunoreactivity in silent chromophobe adenomas: a light and electron microscopic study

Twenty silent human pituitary adenomas were morphologically studied. Immunoperoxidase methods showed numerous adrenocorticotropic hormone-immunoreactive tumor cells in 14 cases by light microscopy and in one additional case by electron microscopy. Three of these cases were positive for beta-endorphin and one for beta-lipotropin by electron microscopy. These immunoreactions were found in undifferentiated tumors as well as in oncocytic adenomas, and could not be related to the presence of basophils by light microscopy. The peptides so detected in silent adenomas may have no biological activity and may correspond to common precursor molecule subunits.     

Thin glomerular basement membrane disease: light microscopic and electron microscopic studies.

Benign recurrent hematuria usually indicates a good prognosis. This condition is associated with abnormally thin glomerular basement membranes. Of 680 renal biopsy cases in which lower urinary tract disease had been excluded by careful study, 25 cases from seven children and eighteen adults met the criteria for thin glomerular basement membrane disease, placing the incidence of the disease at 3.7%. The mean patient age was 32.4 years and the male to female ratio was 1 to 5.3. The primary finding was microscopic hematuria in eighteen patients and gross hematuria in five patients. Among eighteen patients who had microscopic hematuria, one patient also exhibited proteinuria and one patient suffered from acute renal failure due to acute drug-induced interstitial nephritis. Proteinuria was only found in one patient. All of the patients had normal renal function, with the exception of one who suffered from acute renal failure. The duration of hematuria from the time of detection to the date of biopsy ranged from 3 months to 30 years with a mean interval of 56.6 months. No apparent evidence of familial hematuria in any patient was noted. Under light microscopy most glomeruli were normal. However, five cases showed focal global sclerosis. Under immunofluorescence microscopy seventeen cases were negative for all immunoglobulins, for complement, and for fibrinogen. Eight cases showed nonspecific mesangial deposition of fibrinogen and/or IgM. Ultrastructurally, extensive diffuse thinning of the GBM was a constant finding. The mean thickness of the GBM was 203.2 +/- 28.3 nm (n = 25); the thickness in adult (201.4 +/- 27.5 nm; n = 18) did not differ from that in children (208.1 +/- 32.0 nm; n = 7).     

Morphology of neuroblastoma. Light and electron microscopic studies as a contribution on diagnosis and differential diagnosis

The neuroblastoma is one of the most frequent malignant solid tumors in childhood and is thus of great practical importance. The origin of neuroblastoma cells from neural crest derivatives is generally accepted now, and this histogenesis explains some biochemical and morphological characteristics of the tumor. The cytological and histological features of neuroblastomas can be rather varying and, therefore, the diagnosis and differential diagnosis may be difficult. Our study presents the findings of 48 neuroblastomas after light microscopic examination and the ultrastructural characteristics of 8 neuroblastomas and 1 ganglioneuroma. At light microscopic level, completely undifferentiated neuroblastomas and tumors with variable degrees of differentiation were identified. The differentiation of the tumor tissue to ganglion cell-like elements was indicated by an increasing amount of cellular cytoplasm with development of a cytoplasmic process as well as an alteration of the picture of the nucleus (nuclear enlargement and a clearly visible nucleolus). Differentiation to Schwann cell-like elements was occasionally observed, too. Electron microscopically, in all tumors neurosecretory granules could be recognized, and in the better differentiated areas neurite-like cytoplasmic projections were detectable. Thus, the electron microscopy can be a valuable aid in establishing an unequivocal diagnosis. The histology of neuroblastomas is said to be of prognostic significance. Therefore, grading schemes of malignancy were developed. At present, the grading procedure after Hughes and coworkers is mostly used. The criteria of this grading system are presented and interpreted. Finally, those tumors are briefly characterized which play the main role in the differential diagnosis, i.e. juvenile rhabdomyosarcomas, Ewing's sarcoma (including the extraskeletal type), lymphoblastic lymphoma and histiocytic reticulosarcoma. The most important clinicopathologic differences in comparison to neuroblastomas are referred to. Using a large scale of morphologic methods as well as considering clinical and paraclinical parameters, the exact diagnosis of neuroblastoma should be possible in nearly every case.     

Immunoelectron microscopic studies of GH and alpha subunit in GH secreting pituitary adenomas

9 of 15 cases of GH secreting adenomas showed the localization of GH and a subunit in the adenoma cells. GH and a subunit were frequently colocalized in the same adenomas. Immunoelectron microscopically, GH and a subunit were localized in secretory granules which were packed in the cytoplasm. Immunoelectron microscopic double staining (preembedding method and post-embedding method) showed colocalization of GH and a subunit in the same secretory granules. These data suggested corelease of GH and a subunit by the same secretory granules.     

Electron microscopic studies of human pituitary tumors. II. Acidophilic adenomas

Nine cases of acidophilic adenoma associated with acromegaly were studied by electron microscopy. The tumor parenchyma contained numerous cells identifiable as somatotrophs, many of which appeared “normalt” and apparently engaged in protein synthesis. In about half of the specimens, there were variations in the electron-opaque characteristics of the parenchymal cells, most frequently affecting somatotrophs. Characteristic of some somatotrophs was a marked electron-opacity of the cytoplasmic matrix and nuclear materials, irregular cell contours, hypertrophied cytomembrane systems frequently containing proteinaceous material, and considerable amounts of secretory granules. Disruptions in plasma membranes were apparent throughout the parenchyma, particularly at the parenchymal-pericapillary interface. This resulted in the release of large numbers of secretory granules and cytoplasmic fragments to pericapillary or extracellular spaces. Small groupings of the disrupted cells often were characterized by scant secretory granules, an electron-lucent cytoplasmic matrix, and were considered the counterpart of giant multinucleate chromophobes observed with the light microscope. Follicular cells were observed rarely, but when present contained an abundance of fine cytoplasmic filaments and closely resembled follicular cells described in ACTH-secreting tumors.     

Bone tissue in osteogenesis imperfecta: light and electron microscopic studies

Osteogenesis imperfecta was studied by light and electron microscopic techniques in 36 cases, of them there were 10 postmortem and 26 bone biopsies. The persons' age was from 0 to 38 years. There were 25 males and 11 females. The microscopic studies indicated a decrease in the basic substance and an increase in the number of osteocytes. The electron microscopic studies revealed a reduction in the granular endoplasmic reticulum, as well as matrix swelling in the mitochondria, their crista degeneration, and the presence of mitochondrial hydroxyappatite; non-uniform mineralization of collagenous structures, their disintegration, a change in the diameter of collagenous fibril, and a decrease in their transversal lines.     

Electron microscopic studies of human pituitary tumors. I. chromophobic adenomas

Ten cases of chromophobic adenoma have been studied by electron microscopy; seven were associated with hypopituitarism and three with acromegaly. Comparison of the tumors revealed that morphological variations in parenchymal cell types were slight, and, based on characteristics of the secretory granules, a single cell type was predominant and common to both varieties of the tumor. The predominant cell type contained varying amounts of secretory granules that measured 80–200 mμ or more in diameter, and had an electronopaque core and perigranular halo. Though the features of these secretory granules were most like those in “normal” adult basophils this classification is considered doubtful. The core material of the secretory granules was homogeneously electron-opaque in some granules and particulate in others. In addition to electron-opaque core material many secretory granules contained aggregates of clear vesicles. Some granules did not contain clear vesicles but were closely associated with numerous cytoplasmic vesicles. Lysosomes were abundant and a consistent feature of the tumor cells. The present observations indicate that cell features are significantly altered in the cells of both varieties of chromophobic adenoma so that ultrastructural criteria used to identify cell types in “normal” pituitary glands are not applicable to the tumor cells. Chromophobic adenomas associated with acromegaly varied more with respect to the features of the predominant cell type than did chromophobic adenomas associated with hypopituitarism. Cell features varied between cells with electronlucent cytoplasmic matrix and scant development of organelles to others with more electron-opaque cytoplasmic matrix and more complex development of organelles. Common to both varieties of tumor were marked variations in the number and structure of mitochondria from cell to cell; occasionally mitochondria filled the cytoplasm.     

Experimental rabies in skunks: immunofluorescence light and electron microscopic studies.

Striped skunks (Mephitis mephitis) were inoculated into the abductor digiti quinti muscle with street rabies virus isolated from salivary glands of rabid skunks. Using the immunofluorescence technique, antigen was detected in muscle cells at the inoculation site before it was detected in the central nervous system. Neurons and their processes in nearly all regions of the brain, spinal cord, cerebrospinal ganglia, and peripheral nerves contained antigen in terminal stages of the disease. Electron microscopically, matrix (viral nucleocapsid), virions, and anomalous viral products were mainly in neuronal perikarya and dendrites, and less often in myelinated axons. Matrices, virions, and crystalloid structures were in muscle fibers at the inoculation site. Viral budding occurred on endoplasmic reticulum, neurotubules, and neuronal plasma membrane. In the brain and dorsal horn of the spinal cord, virus budded from the postsynaptic and adjacent dendritic or perikaryal plasma membrane. There was simultaneous esotropic uptake of these particles by adjacent axon terminals. The results strongly suggest that direct transneuronal transfer of virus from perikarya and dendrites to adjacent axon terminals is a mechanism in dissemination of rabies in the central nervous system of striped skunks. Variation in the length of the incubation period may be due partly to replication or virus in myocytes at the inoculation site and subsequent transfer to peripheral nerves.     

Virilizing lipid cell tumor of the ovary: light and electron microscopic studies

Lipid cell tumor of the ovary is among the rarest tumors belonging to the virilizing group of ovarian neoplasms. A lipid cell tumor of the ovary is described in an 18-year-old woman with secondary amenorrhea, hirsutism, and frank virilization. Current diagnostic features, preoperative and postoperative androgen determinations, and histomorphological and ultrastructural studies are presented. Prompt diagnosis and treatment are emphasized in this potentially malignant and disfiguring androgenic tumor that is readily amenable to surgery.     

J chain synthesis in human myeloma cells: light and electron microscopic studies

The presence of J chain in human immunocytes containing various immunoglobulin classes has already been reported and in this paper we investigated the presence of J chain in human myeloma cells using light and electron microscopy. Myeloma cells were positive for cytoplasmic J chain in thirteen cases: six of fifteen IgG myeloma, two of seven IgA myeloma, two of nine B-J myeloma and three of three primary macroglobulinaemia. None of the four with benign monoclonal gammopathy was positive for J chain. The ultrastructural localization of J chain in IgG myeloma cells was similar to that of gamma chain, i.e. around the nuclear membrane, in the endoplasmic reticulum (ER) and in the Golgi apparatus. The latter finding is compatible with the presence of J chain in the urine of the same patient. We examined the urine from nine patients with J chain-positive cells and secretion of J chain was confirmed in three patients: two with IgG myeloma and one with B-J myeloma. In noe of twelve in whom the immunocytochemical findings were negative for J chain was there evidence of urinary J chain.     

Cytoarchitecture of the normal rat olfactory epithelium: light and scanning electron microscopic studies

The three-dimensional cytoarchitecture of the normal rat olfactory epithelium was examined by scanning electron microscopy (SEM) of KOH digested tissues as well as by light and transmission electron microscopy of plastic sections. Observations specimens from the lateral side of the olfactory epithelium allowed identification of four cell types by their surface structure: olfactory neurons, supporting cells, basal cells, and duct cells of the Bowman's gland. The olfactory neurons were characterized by the presence of a thick apical process (i.e., dendrite) and a thin basal process (i.e., axon). These olfactory neurons tended to be aligned along the vertical axis of the epithelium. Immature olfactory neurons were present at the basal part of the epithelium and had a pear-shaped cell body with a thin and long axon and a short dendrite which failed to reach the epithelial surface. Supporting cells were roughly columnar in shape and occupied the full length of the epithelium. They became thinner in the basal two thirds of their length but had branched foot processes spreading on the basal surface of the epithelium. Basal cells located in the basal epithelial region were oval, round or cuboidal and present among the foot processes of the supporting cells. The ducts of the Bowman's gland entered the epithelium from the lamina propria and took straight, perpendicular courses within the epithelium. These intraepithelial ducts were composed of several slender cells. The acinar cells are sometimes present in the epithelium and appeared as a globular bulge of the duct at the basal part of the epithelium. SEM observation of the basal surface of the olfactory epithelium also clearly showed that axon bundles were surrounded by the sheet-like processes of Schwann cells, the investment being found at the base of the epithelium just before axon bundles leave the epithelium.     

Histochemical light and electron microscopic investigations on an eosinophilic granuloma]

An eosinophilic granuloma has been investigated by means of histochemical proofs for enzymes and tissue elements and common staining methods. The best method was be found the proof for the enzyme phenol oxidase (EC 1.14.18.1). In this way it is possible to determine eosinophils rapidly and surely and to receive an overview on the frequency and distribution of these cells. The histiocytic-like cells was identified electron microscopical as Langerhans' cells. This cells are in narrow contact to many eosinophilic granulocytes. Their granula have manifold changes in their structure. The granula are possibly able to produce new structures of the cell. The eosinophilic granuloma correspond to a cell mediating immunological defence reaction approximate to the type of a delayed hypersensitivity.