Effect of various irrigating fluids on the ultrastructure of articular cartilage.

The effect of five different irrigating fluids on the ultrastructure of articular cartilage was studied utilizing the scanning electron microscope. Gross histologic studies have shown no significant difference amongst commonly used irrigating fluids on the surface or matrix composition of articular cartilage. Recent in vivo and in vitro biochemical studies, in addition, have shown no significant deleterious effects of irrigating fluids on articular cartilage composition. This study was prospectively undertaken to assess the effect of irrigating fluids on the ultrastructure of articular cartilage. When comparing five irrigating solutions utilizing the scanning electron microscope, specimens irrigated with 1.5% glycine seemed to show a more consistently smooth appearance. Ultrastructural changes were noted with the other four irrigating solutions tested.

A rapid DNA probe test for detecting human papilloma virus types 6/11 and 16 in biopsy specimens.

A simple, rapid and sensitive non-radioactive in situ hybridization assay for human papillomavirus (HPV) has been developed and used to detect HPV 6/11 and HPV16 DNA in ano-genital biopsy specimens. A comparative study to determine the sensitivity and the specificity of this assay relative to Southern blot hybridization assays was performed using one hundred biopsy specimens. The sensitivity of the in situ hybridization assay was 88% for HPV type 6/11 and 89% for HPV type 16. The specificity of the test was 99% for both virus types. In addition to its high sensitivity and specificity, this in situ hybridization assay for HPV uses a non-radioactive detection system. The assay is faster and easier to perform than the Southern blot method. Also, in situ hybridization assays permit the simultaneous evaluation of the histology, as well as the DNA content of biopsy tissues because they do not result in the destruction of tissue or cell morphology. This prototype HPV DNA assay was developed using DNA probes for HPV 6/11 and HPV 16 DNA in anogenital biopsy specimens. However, the protocol developed in these studies can easily be extended to include the use of probes for detecting other HPV types in a variety of tissues.

Proteinuria in a child with sialidosis: case report and histological studies.

A 9-year-old body with sialidosis had nephrotic-range proteinuria. Histological studies demonstrated massive distension of renal cells, particularly glomerular visceral epithelial cells, by cytoplasmic vesicles which contained material reactive with concanavalin A and wheat-germ agglutinin. In addition, some glomeruli exhibited segmental mesangial thickening or glomerulosclerosis. Ultrastructurally, focal detachment of visceral epithelial cells from the underlying glomerular basement membrane was observed. We postulate that glomerular visceral epithelial cell dysfunction may underlie the proteinuria and focal glomerulosclerosis exhibited by this patient. Hyperfiltration, as suggested by the child's elevated creatinine clearances, may be a contributing factor.

The gastric mucosal barrier: tight junction structure in gastritis and ulcer biopsies.

Tight junctions of the human gastric mucosa were examined using quantitative freeze-fracture methods. Biopsies examined were from patients with gastric diseases including gastritis, ulcers, and pernicious anemia. No significant differences were seen in strand number or tight junction complex depth among the biopsies analyzed, however, anomalous tight junction structures were observed. Discontinuities in the tight junctions complex and hyperplastic tight junctions (extensions of the apical tight junction strands radiating over the lateral plasma membrane) were seen. These alterations were not associated exclusively with either the diagnosis of gastritis or ulcers. However, a higher frequency of tight junction breaks was seen in stomach biopsies diagnosed as gastritis while those diagnosed as ulcers displayed a higher occurrence of hyperplastic tight junctions.

The effects of 16,16-dimethyl prostaglandin E2 + aspirin on the canine gastric mucosal barrier.

The canine gastric epithelium was exposed to solutions containing 20 mM aspirin and 20 mM aspirin + 30 micrograms/kg 16,16-dimethyl prostaglandin E2 (dmPGE2) for periods of three and forty minutes. No macroscopic hemorrhagic lesions were seen. Light microscopically, surface lesions were reduced from 10 percent (aspirin alone) to 2.5% (aspirin + dmPGE2). However, dmPGE2 does not appear to attenuate aspirin induced tight junction alterations. Discontinuities in the apical occluding complexes, hyperplastic tight junctions and stand number variability were documented in freeze fracture replicas of aspirin as well as aspirin + dmPGE2 treated dog stomachs. The results of these experiments would seem to suggest that 30 micrograms/kg dmPGE2 does not prevent aspirin induced damage to the tight junctions of the canine gastric epithelium or enhance their repair.

Effects of aspirin on tight junction structure of the canine gastric mucosa.

The effects of aspirin on the canine gastric mucosal barrier were examined using the freeze-fracture and extracellular tracer techniques. Aspirin treatment (3, 20, or 40 min) resulted in alterations in tight junction complex morphology and permeability. Discontinuities in the apical occluding complex, hyperplastic tight junctions (extensions of the apical tight junction strands radiating over the lateral plasma membrane), and a variability in the number of strands (1-20) comprising the complex were observed. A concurrent increase in lanthanum permeability between nonnecrotic surface mucous epithelial cells was also demonstrated. The results of these experiments may suggest that aspirin-induced impairment of the tight junction complexes between viable gastric mucosal epithelial cells may be a major contributing factor in the etiology of stomach disorders.

Gap junctions between gonocytes and epithelial cells in the sex cords of the one day old rat. A freeze fracture study.

In this report we document the presence of gap junctions between gonocytes and epithelial cells in the sex cords of the one day old rat. Morphologically these junctions are comparable to those seen between germ and Sertoli cells in the adult rat seminiferous epithelium. The possibility that gap junctions the adult rat seminiferous epithelium. The possibility that gap junctions between germinal and supporting elements in the one day old rat and in the adult have similar functional roles is also discussed. day old rat and in the adult have similar functional roles is also discussed.

Plasmacytoma with oncocytic changes. A case report.

In this report we will document a readily identifiable, morphologic variant of plasma cells in an extramedullary plasmacytoma. Ultrastructurally, the tumor cell cytoplasm was almost completely occupied by proliferating mitochondria. Localized areas of endoplasmic reticulum were, however, also noted. The light microscopic features of this tumor (i.e. foamy eosinophilic cytoplasm) and special staining (methyl green pyronin (MGP) characteristics were compatible with the fine-structural details of these cells. The usefulness of obtaining a clinical/pathological correlation for the behavior of this type of tumor is discussed.

The gastric mucosal barrier: structure of intercellular junctions in the dog.

The canine gastric mucosa consists of two regions, the surface mucous cells and gland area cells including parietal, chief, and mucous-containing cells. We have used quantitative freeze-fracture methods in conjunction with thin-section extracellular tracers to document and correlate tight junction morphology with epithelial permeability. The number of strands in the tight junction complexes of the surface cells and gland cells is the same, but differences in strand arrangement exist. The surface cells have an interwoven tight junction configuration which is impermeable to extracellular tracers. The gland cell junctions are regularly arranged and often permeable to extracellular lanthanum. The possibility that the observed difference in permeability between the tight junctions of the surface mucous cells and those of the gland cells is related to their structural configuration is discussed.

The use of fresh-frozen tissue in diagnostic transmission electron microscopy.

We have examined the effects of freezing on fresh pathologic human tissue specimens with regard to the fine structural preservation of various organelles that can be of diagnostic importance. Specimens included in this study were frozen either in the cryostat (-20 degrees C) or by quenching in isopentane cooled by liquid nitrogen (-115 degrees C). The results indicate that fresh-frozen tissue that is subsequently fixed and processed for transmission electron microscopy (TEM) provides ultrastructural information that is very nearly equal to that of conventionally processed specimens. Additionally, we performed identical freezing experiments using animal (rat) tissue in order to ensure that the results we obtained using a rather limited number of human specimens were valid. The outcome of these animal experiments thoroughly supports our observations using human pathologic tissue. We believe an appreciation of the fact that fresh-frozen tissue is suitable for TEM examination may become a very valuable resource in the surgical pathology laboratory.

Microtubuloreticular structures in the cerebral vasculature of a patient with herpes simplex encephalitis.

In this report we will document the presence of microtubuloreticular structure (MTRS) in the cerebral vasculature of a patient who had contracted herpes simplex (HSV) encephalitis. Twenty of twenty-one blood vessels (capillaries, arterioles, venules) contained MTRS within the cytoplasm of endothelial and/or associated cells. The use of this evidence to support a diagnosis of HSV encephalitis is discussed.

Occluding junctions in an epithelioid mesothelioma: a freeze-fracture study.

The presence of a well-developed tight junction system in a case of diffuse, papillary, malignant mesothelioma of the peritoneum is documented using the freeze-fracture methodology. The mean number of strands within the tight junction network was determined to be 3.83 +/- 0.16. In addition, the tight junctions were specifically located in regions of the plasma membrane adjacent to recognizable microvilli. Gap junctions and desmosomes were found in close association with the occluding complexes; however, they were also seen in areas of the plasma membrane quite distinct from those that exhibit tight junction differentiation. The possible significance of the presence of tight junctions in neoplastic epithelial cells is also discussed.

Electron microscopic identification of the colorectal origins of tumor cells in pleural fluid.

Cellular material from metastatic rectal and lung adenocarcinomas was recovered from pleural and pericardial fluids, respectively. It was examined by electron microscopy (EM) to determine if certain ultrastructural features, which are primarily prominent in colorectal adenocarcinomas, were maintained in the tumor cells in metastatic fluid. These features include the presence of microvilli with dense microfilamentous cores that extend deeply into the apical cytoplasm (cytoplasmic rootlets) and an abundance of glycocalyceal bodies. It was found that tumor cells from the patient with a primary rectal adenocarcinoma exhibited these critical distinguishing characteristics. The cells from the lung adenocarcinoma, while containing many well-developed microvilli, did not possess cytoplasmic rootlets or glycocalyceal bodies. In addition, and possibly of more diagnostic significance, is the observation that the presence of microvilli and cytoplasmic rootlets remained evident in tissue pieces and cell blocks initially processed in paraffin and then reembedded for EM.

Toxic shock syndrome: clinical, laboratory, and pathologic findings in nine fatal cases.

Clinical, laboratory, and pathologic findings in nine of the 12 patients who died from toxic shock syndrome in Minnesota are reported. All patients met the toxic shock syndrome case definition except for desquamation, which occurred in only one patient. Eight were menstruating and at least four were wearing tampons at the time of the acute illness. One patient was using napkins only. Noncardiogenic pulmonary edema was the only clinical development that could be used to predict a fatal outcome. Specific pathologic findings included various degrees of fatty metamorphosis of the liver; pronounced hemophagocytosis by reticuloendothelial macrophages; and a characteristic vaginal lesion consisting of mucosal separation beneath the basal layer with ulceration, severe vasodilatation, inflammation and thrombosis, but with minimal bacterial invasion. This vaginal lesion was noted in two tampon users, but an identical lesion was found in a menstruating patient who used only napkins.

Ectopic immature renal tissue over the dorsum of lumbar and sacral area in two infants.

During reparative surgery for meningomyelocele of the lumbar area, a 7-week-old female infant was found to have a small, well-delineated, subcutaneous, renal blastema. A 3-month-old female infant was found to have immature renal tissue, consisting of glomeruli and tubules, in a soft tissue swelling dorsal to the sacrum. Neither of these patients showed neurologic or renal abnormalities. The second patient has had a disease-free follow-up period of six years. The possible etiology and significance of these benign findings and their relation to the origin of Wilms tumors are discussed.

Membrane associations between subsurface cisternae of endoplasmic reticulum and the plasma membrane of rat Sertoli cells.

Close membrane associations between the endoplasmic reticulum and the plasma membrane (ER-PM) occur in specialized regions of the rat Sertoli cell cytoplasm. They are characterized, in freeze fracture replicas, as mesa-like modifications of E membrane fracture faces or as corresponding discoid depressions on P membrane fracture faces. When these structures lie along transitional regions in the membrane fracture plane, they are seen to be complementary, and the space between them to be greatly reduced. These specialized close membrane associations may represent adhesive sites between the endoplasmic reticulum and the plasma membrane. However, their resemblance to vascular endothelial fenestrae which are known to be sites of increased membrane permeability may suggest other functional roles.

Cell processes in basal cell carcinoma.

Three cell process types are described in basal cell carcinoma. The most abundant are thin processes resembling microvilli; thick processes, mesa-like structures often surmounted by desmosomes; and large bulging processes. Processes occur in the intercellular spaces, and are more numerous in spinocellular cells than in basaloid cells. Despite the abundance of processes in basal cell carcinoma, they do not usually penetrate the basal lamina border of the tumor. This behavior differs from more rapidly invasive squamous cell carcinoma where processes extend through the fragmenting basal lamina into the stroma.