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Biomedical subjects

D McGinley

Publications and source records attributed to D McGinley.

15 recordsLinked to original sources
PubMed1990

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.

Adult↗
PubMed1989

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.

Adult↗
PubMed1987

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.

16,16-Dimethylprostaglandin E2↗
PubMed1986

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.

Animals↗
PubMed1985

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.

Aged↗
PubMed1984

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.

Animals↗
PubMed1984

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.

Freeze Fracturing↗
PubMed1979

Intercellular junctional specializations in human basal cell carcinoma. A freeze-fracture study.

Intercellular junctions of various types were found on the membrane fracture faces of human nodular basal cell carcinoma (BCC) cells. The junctional types represented include desmosomes, tight junctions, and gap junctions. A semiquantitative comparison of undifferentiated and differentiated nodular BCC showed that gap and tight junctions were observed on all exposed membrane fracture interfaces of the differentiated tumors, while only fifty six per cent of the membrane interfaces of the undifferentiated tumor exhibited similar junctional specializations. These membrane specializations may be a partial reflection of differentiation among the different types of BCC and their contribution to the less invasive character of nodular BCC cannot be ruled out.

Basal Cell Carcinoma↗
PubMed1978

Development of Sertoli cell junctions in vitro--a freeze-fracture study.

Seminiferous tubules of 1-day-old rats were maintained in organ culture for up to 40 days. Five classes of intercellular junctions between Sertoli cells were observed by the freeze-fracture method as the tissue aged: (a) typical gap junctions; (b) focal tight junctions; (c) macular tight junctions; (d) meandering tight junctions; and (e) extensive tight junctions. The relative proportions of these types of Sertoli cell junctions were quantitated as the organ cultures progressed. The junctional structures observed and classified in organ culture were identical to those seen in vivo, but the timing of their appearance and/or disappearance, as well as their relative proportions, was different from that observed in the developing animal. Extensive tight junctions, with numerous parallel strands, were observed in the 40-day cultures; however, their oblique orientation with respect to the myoid layer was in contrast to the parallel orientation observed in vivo.

Animals↗
PubMed1978

Pigmented penile papules with carcinoma in situ changes.

Benign appearing, multifocal, pigmented penile papules were found in three patients, showing the histopathological and electron microscopic changes of carcinoma in situ. Their clinical appearance, relation to other carcinoma in situ lesions, as well as possible pathogenesis are discussed.

Adult↗
PubMed1977

Intercellular junctional complexes of the rat seminiferous tubules: a freeze-fracture study.

This paper provides a description of the intercellular junctions in the rat testis, as observed using the freeze fracture technique. These intercellular junctions were categorized into four general types: Sertoli cell tight junctions, myoid cell tight junctions, gap junctions, and "heterogeneous junctions." The Sertoli cell tight junctions had a mean depth of 3.1 micron in the basal to apical direction, and contained 25 to 50 (average: 36) parallel rows of particulate sealing elements. The myoid cell tight junction was neither continuous nor extensive, but focal in nature. Interestingly the sealing elements of this junction, like those of the Sertoli cell tight junction, were quite particulate in nature. Typical gap junctions were observed between Sertoli cells where they were intercalated between the parallel rows of the Sertoli cell tight junction. The most interesting observation was the identification of gap junction-like structures, in various stages of formation, on germ cell membrane fracture faces, both in the basal and adluminal compartments. Lastly, the unusual "heterogeneous junction" was observed on large membrane fracture faces in close proximity to cells in the adluminal compartment, presumably between Sertoli cells. These junctions appeared to consist of both tight and gap junction elements.

Animals↗
PubMedDate not supplied

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.

Adenocarcinoma↗