Loss of anionic sites on the glomerular basement membrane in transplant glomerulopathy.

We studied anionic sites on the glomerular basement membrane in patients with chronic renal transplant rejection having clinical and histological features of transplant glomerulopathy. All patients had significant proteinuria (greater than 1 g/24 h as well as light- and electron-microscopic features very like focal segmental glomerulosclerosis, though no patient had that disease in the native kidney. A significant reduction in the density and absolute number of anionic sites was observed compared with controls and with patients having stable graft function. The findings suggest that the loss of anionic sites may play an important part in the pathogenesis of transplant glomerulopathy.

Processing fine needle aspiration biopsies for electron microscopic examination. Experience implementing a procedure.

While processing needle rinses from fine needle aspiration biopsy material for electron microscopy, we experienced difficulties not fully outlined previously. Problems in preservation were traced to the time elapsed before glutaraldehyde was added to the needle rinse, which had been held in a physiologic transport medium; a tendency toward hypotonicity of the commercially prepared transport medium; and vigorous handling of the needle rinse. When these problems were dealt with, preservation improved dramatically. The problem of scanty material available for ultrastructural evaluation was dealt with by decreasing the number of smears made and filtering the needle rinse to capture tissue fragments. Implementation of the procedure required leadership, good communication, motivated cytotechnologists and cytopathologists, and continuous supervision and monitoring. In cases with adequately cellular well-preserved material available for electron microscopy, ultrastructural evaluation made a contribution of clinical value to the diagnosis in 48% of cases.

Intracytoplasmic lumina in squamous epithelial lesions of the oral cavity.

Intracytoplasmic lumina are considered a diagnostic feature of adenocarcinomas and have not been reported in squamous cell carcinomas. We are documenting intracytoplasmic lumina in a case of primary squamous cell carcinoma of the oral mucosa and in the oral squamous mucosa in two cases of graft versus host disease, confirming that intracytoplasmic lumina are also present in squamous epithelia and their tumors. Likely explanations for the presence of intracytoplasmic lumina in non-neoplastic and malignant squamous cells of the oral cavity include multiple differentiation, phagocytosis and immune attack on desmosomes.

Major histocompatibility complex class II-restricted cytotoxicity by self-myelin basic protein-reactive T-cell hybridomas: evidence for a tumour necrosis factor-independent nucleolytic mechanism.

Direct cytotoxicity by class II-restricted T cells has been proposed as a potential mechanism in autoimmune tissue damage, as well as in immunoregulation. We used I-A(s)-restricted non-granular cytotoxic T-cell hybridomas (BP24.29 and BP47.7), specific for self-determinants on myelin basic protein (MBP), and different monoclonal targets, in order to characterize the mechanism of killing used by these cells. An early lesion at the level of the target cell nucleus was indicated by the fact that target DNA lysis ([3H]thymidine release) proceeded 2-2.5-fold as rapidly as cytoplasmic lysis (51Cr release) over the first 14 hr after stimulation. Cytotoxicity was relatively resistant to inhibition by anti-calcium agents (TMB-8 and verapamil), even under conditions which blocked interleukin-2 (IL-2) release. Although tumour necrosis factor (TNF) has been proposed as one mediator of class II-restricted cytotoxicity, these cells (i) released no detectable TNF after stimulation with antigen, concanavalin A (Con A), or anti-CD3, (ii) readily lysed TNF-resistant targets (A20 and LS-102.9), and (iii) had no cytotoxic effect on TNF-sensitive cells (L929). Substantial 'bystander' killing of I-A-mismatched targets was observed, which was 13-37% of the cognate (I-A(s)-restricted) cytotoxicity measured in parallel. This finding may indicate an effector mechanism in autoimmune demyelination, since the myelin-forming oligodendrocytes of the central nervous system are not inducible for major histocompatibility complex (MHC) class II expression.

Fine-needle aspiration biopsies of metastatic neuroendocrine tumors in liver: use of transmission electron microscopy and protein A gold technique in diagnosis.

Five fine-needle aspiration biopsies of liver were studied to evaluate the use of electron microscopy and protein A gold technique in the diagnosis of metastatic neuroendocrine tumors. All five cases had cytologic features suggestive of neuroendocrine tumors and neurosecretory granules on ultrastructural examination. The aspirates were stained by the immunoperoxidase technique and the postembedding protein A gold technique using the antibody to chromogranin A. Three cases were positive for chromogranin A by both immunoperoxidase and protein A gold techniques. Two cases were positive by protein A gold technique and negative by immunoperoxidase technique. Confirmation of neurosecretory granules by immunochemistry is ideal, since ultrastructurally they can be mimicked by other electron-dense inclusions. Advantage of the protein A gold technique is the use of the same material for both ultrastructural evaluation and the protein A gold technique.

Angiosarcoma of the uterus: a case report.

We are reporting a case of angiosarcoma of the uterus in which the diagnosis was confirmed ultrastructurally by demonstration of Weibel-Palade bodies in the tumor cells. Only 10 cases of this entity have been previously documented in the literature.

Acinic cell carcinoma metastatic to the brain: case report and ultrastructural study.

We report a case of isolated cerebral metastasis from an acinic cell carcinoma, which arose in minor salivary glands 20 years previously. The clinical, pathologic and ultrastructural features are described, together with a review of the literature, which suggests that this is an unusual occurrence.

Demonstration of Epstein-Barr virus in immunoblastic sarcoma of B-cells arising in a child with primary immunodeficiency disease.

The subject of this investigation was an 11-month-old infant girl who presented with a pathological fracture of the right femur due to a metastasis from an abdominal immunoblastic sarcoma. Her past history included recurrent, intractable bacterial and fungal infections. Investigations of her immune status revealed low numbers of T-lymphocytes, a reversed T-helper (TH)/T-suppressor (TS) cell ratio, no response of her peripheral blood lymphocytes to pokeweed mitogen, phytohemagglutinin, concanavalin A, and Candida albicans, and an inability of her cells to react in a mixed lymphocyte culture. Serum levels of IgG, IgM, and IgA were all below normal. No thymic shadow was visible on the chest radiograph. There was no evidence of adenosine deaminase or nucleoside phosphorylase deficiencies. The tumor cells exhibited both surface IgM and IgG, and many of the cells contained large amounts of cytoplasmic IgM. Light chain specificity was restricted to lambda chain for both surface and cytoplasmic immunoglobulin. Ultrastructural study of the tumor cells revealed the presence of both intranuclear and cytoplasmic virions in roughly 1% of the tumor cells. These viral particles strongly resembled herpes viruses. DNA-hybridization studies on the neoplasm revealed the presence of 7-10 genome equivalents of Epstein-Barr virus-DNA per tumor cell.

Congenital ependymoblastoma presenting as a sacrococcygeal mass in a newborn: an immunohistochemical, light and electron microscopic study.

We describe a case of congenital ependymoblastoma presenting as a subcutaneous mass in the sacrococcygeal area of a newborn male. The tumor was composed of primitive cells disposed in compact sheets and cords and exhibiting focal ependymal differentiation. No other line of cellular differentiation was identified by either immunohistochemistry or ultrastructural study. Elevated serum alpha-fetoprotein was found, which decreased following surgical extirpation of the tumor. We propose that this tumor had its origin in the ependymal medullary vestige, similar to other sacrococcygeal ependymomas.

Nonsecretory parathyroid carcinoma of the mediastinum. Light microscopic, immunocytochemical, and ultrastructural features of a case, and review of the literature.

Nonsecretory parathyroid carcinoma is rare, particularly in extracervical sites. The authors present a case of a 51-year-old man with a large mediastinal mass that was found on a chest x-ray. Light and electron microscopy and immunohistochemical analysis of the resected tumor disclosed findings consistent with parathyroid carcinoma. Clinical and laboratory evaluations failed to reveal evidence of hyperparathyroidism. The nonsecretory state of the tumor was further supported by immunoreactivity for parathormone in tissue sections and, at the same time, normal levels of this peptide in serum. Partial shrinkage of the mediastinal mass occurred after 11 months of combined chemotherapy, with subjective improvement. A literature review of both secretory and nonsecretory parathyroid carcinomas was undertaken, revealing similar clinical features with regard to mean age, age range, and sex incidence among both groups.

Malignant intracranial fibrous histiocytomas. Histologic, ultrastructural and immunohistochemical studies of two cases.

Two cases of malignant intracranial fibrous histiocytoma are presented. In Case 1 the tumour arose from the meninges and showed a disseminated spread throughout the neuroaxis. In the second case the tumour appeared to arise from within the brain substance. In this case surgical intervention and radiotherapy appeared to have achieved a cure, since no residual tumour was found at autopsy. The tumours were examined using ultrastructural and immunohistochemical techniques, which appeared advantageous in delineating this rare tumour from other intracranial neoplasms.

Transmission electron microscopy of horse embryos 3-16 days after ovulation.

The 23 embryos were obtained by flushing the reproductive tract. Though the general cytology was observed, most attention was given to the formation of the embryonic capsule. It first appeared as a thin uniform layer on the inner surface of the zona pellucida of embryos recovered from the uterus on Day 6. By Day 8 the capsule was about 1 micron thick and the zona pellucida had been shed. In fixed embryos of 11 days and over the capsule was 3 microns thick and had a finely stippled but otherwise homogeneous appearance.

Distribution of neurofilaments in myelinated axons of the optic nerve of goldfish (Carassius auratus L.).

Neurofilaments were counted in myelinated axons of the optic nerve of goldfish which were acclimated to 5 degrees and 25 degrees C. The number of neurofilaments increases markedly with increasing axonal size; axons of less than 0.1 micrometer 2 in area contain between 25 and 60 neurofilaments, while in the larger axons of area greater than 1.0 micrometer 2 there are approximately 190. The densities of the neurofilaments in the small axons are noticeably higher than in the larger ones (507 and 160, respectively). A variety of fixation procedures i.e. osmium tetroxide (OsO4) in phosphate buffer, glutaraldehyde (4%) in phosphate buffer or in ethyleneglycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) and piperazine-N-N'-bis-(2-ethanesulphonic acid) (PIPES) and post-fixed with OsO4 had no effect on the numbers of neurofilaments relative to the size of axon. The anaesthetic MS-222 (tricaine methanesulphonate) likewise had no effect on the numbers of neurofilaments. It is proposed that temperature acclimation alters the axon diameter concomitant with an alteration in the number of neurofilaments to fit the new diameter of the axons.