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Biomedical subjects

J L Olson

Publications and source records attributed to J L Olson.

82 records · Page 5Linked to original sources
PubMed1977

Fine structural studies of a human thyroid adenoma, with special reference to psammoma bodies.

The fine structural morphologic features of a microfollicular thyroid adenoma from a 28 year old female were examined. Although the patient had been laking exogenous thyroxine therapy for 14 months, the morphology of the adenoma was characterized by numerous small to medium sized follicles composed of metabolically active, well differentiated columnar cells with numerous colloid droplets, dilated granular endoplasmic reticulum, large numbers of coated vesicles and lysosomes, large colloid containing "lakes," microtubules, microfilaments, and prominent apical microvillous projections. Of special inetrest were small spherical psammomatous calcospherites ecountered in histiocytes and the interstitium. Also noteworthy were ropelike configurations observed in most of the follicular lumina. Structural-functional correlations and potential origins of psammoma bodies and calcospherites are discussed.

Adenoma↗
PubMedDate not supplied

Repeat dilation of Palmaz stents in pulmonary arteries: study of safety and effectiveness in a growing animal model.

PURPOSE: This study assessed the technical feasibility and safety of repeat dilation of Palmaz stents in growing pulmonary arteries. MATERIALS AND METHODS: Palmaz stents (1.2 cm long) were placed percutaneously into the pulmonary arteries of 20 newborn lambs. After 4 months, pulmonary arteriography was performed. Where vessel growth in excess of stent diameter had created a stenosis (> 15%), stents were dilated again percutaneously. Six months later, pulmonary arteriography was performed, before the animal was killed and histologic examination performed. RESULTS: Twenty-four pulmonary artery stent placements were attempted; 23 were successful. One stent placement was unsuccessful owing to stent displacement from the balloon. Acute complications included branch pulmonary artery occlusion (n = 3) and stent displacement from the delivery balloon (n = 2). At 4 months, the desired degree of stenosis (> 15%) was achieved in 11 animals. The average stenosis was 35% (standard deviation, 16%; range, 17%-66%). The mean predilation stent diameter was 6 mm +/- 1.1 (range, 4-8 mm), and the final diameter of 8 mm +/- 1.4 (range, 6-10 mm), represented a 35% mean increase (P < .001). Complications included stent (n = 1) and branch vessel (n = 1) thrombosis. At 6-month follow-up, all stents were patent. Areas of previously noted branch thrombosis were fully recanalized in all cases. At histologic inspection, only a thin layer of neointima was found on the stents. CONCLUSION: Repeat dilation of Palmaz stents may be safely performed in growing pulmonary arteries in an animal model. Neointimal hyperplasia is minimal in pulmonary artery stents.

Animals↗
PubMedDate not supplied

Subcutaneously tethered temporary filter: pathologic effects in swine.

PURPOSE: To evaluate the histopathologic effects of the Tempo-filter, a temporary caval filter, on the caval wall and determine the feasibility of deployment and removal of the device in swine. MATERIALS AND METHODS: Filters were placed in the infrarenal inferior vena cava of 11 swine. The tethering catheter was sutured in a subcutaneous pocket near the puncture site. The original tethering catheter used in humans and a stiffer catheter designed to prevent migration in swine were evaluated. Postplacement, mid-study, and preexplant vena cavography procedures were performed. Four swine underwent in situ dissection at 3-10 weeks. Filters were removed from seven animals just before they were killed at 1-6 weeks. RESULTS: All filters were successfully placed. All seven filters were successfully removed at up to 6 weeks after placement. Cephalic migration of more than 1 cm was observed in 10 of 11 swine (100% of original catheters, 83% of stiff catheters). Other complications were more common with stiffer tethering catheters, including caval stenosis in 40% of original catheters and 100% of stiff catheters, filter cone thrombus in 0% and 67%, tethering catheter thrombus in 20% and 83%, pulmonary embolism in 0% and 50%, and death in 0% and 17%, respectively. There was mild vessel wall damage in the vena cava. CONCLUSION: Placement of the Tempofilter and removal at up to 6 weeks after placement is feasible.

Animals↗
PubMedDate not supplied

Arterial delivery of genetically labelled skeletal myoblasts to the murine heart: long-term survival and phenotypic modification of implanted myoblasts.

The ability to replace damaged myocardial tissue with new striated muscle would constitute a major advance in the treatment of diseases that irreversibly injure cardiac muscle cells. The creation of focal grafts of skeletal muscle has been reported following the intramural injection of skeletal myoblasts into both normal and injured myocardium. The goals of this study were to determine whether skeletal myoblast-derived cells can be engrafted into the murine heart following arterial delivery. The murine heart was seeded with genetically labeled C2C12 myoblasts introduced into the arterial circulation of the heart via a transventricular injection. A transventricular injection provided access to the coronary and systemic circulations. Implanted cells were characterized using histochemical staining for beta-galactosidase, immunofluorescent staining for muscle-specific antigens, and electron microscopy. Initially the injected cells were observed entrapped in myocardial capillaries. One week after injection myoblasts were present in the myocardial interstitium and were largely absent from the myocardial capillary bed. Implanted cells underwent myogenic development, characterized by the expression of a fast-twitch skeletal muscle sarcoendoplasmic reticulum calcium ATPase (SERCA1) and formation of myofilaments. Four months following injection myoblast-derived cells began to express a slow-twitch/cardiac protein, phospholamban, that is normally not expressed by C2C12 cells in vitro. Most surprisingly, regions of close apposition between LacZ labeled cells and native cardiomyocytes contained structures that resembled desmosomes, fascia adherens junctions, and gap junctions. The cardiac gap junction protein, connexin43, was localized to some of the interfaces between implanted cells and cardiomyocytes. Collectively, these findings suggest that arterially delivered myoblasts can be engrafted into the heart, and that prolonged residence in the myocardium may alter the phenotype of these skeletal muscle-derived cells. Further studies are necessary to determine whether arterial delivery of skeletal myoblasts can be developed as treatment for myocardial dysfunction.

Animals↗
PubMedDate not supplied

Ultrastructural evidence of cell-mediated endothelial cell injury in cardiac transplant-related accelerated arteriosclerosis.

Accelerated arteriosclerosis secondary to chronic allograft rejection is a major long-term complication of heart transplantation. Accelerated arteriosclerosis has been associated with an endothelialitis, and the majority of the involved inflammatory cells are T lymphocytes and macrophages. Coronary arteries from six heart allograft recipients with transplant-related arteriosclerosis were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Four hearts were explants from heart transplant recipients with severe accelerated arteriosclerosis who were undergoing retransplantation, and two were obtained from autopsied recipients. The patients ranged in age from 6 to 60 years (mean, 44 years). The graft survival for these six hearts ranged from 1.4 to 5.6 years (mean, 4.3 years). Lymphocytes, macrophages, and smooth muscle cells were identified by TEM in the intimas of all the vessels examined. The lymphocytes were often in contact with macrophages or in close proximity to injured endothelial cells. Areas of endothelial injury were characterized by vacuolization of endothelial cells and partial denudation of the endothelium with fibrin deposition. SEM also revealed endothelial cell injury with disorganization of the endothelium and gaps between endothelial cells. Leukocytes and platelets were often noted in these gaps. These findings suggest that accelerated arteriosclerosis in heart transplant recipients is associated with an accumulation of macrophages, lymphocytes, and smooth muscle cells in the intima as well as with lymphocyte-directed endothelial injury.

Adult↗
PubMedDate not supplied

Cytopathology of pleural effusions after radiotherapy.

The cytomorphology of pleural effusions following ionizing radiotherapy (IRT) has not been studied systematically. To determine if IRT produces alterations in pleural fluids that affect the cytopathologic interpretation of these specimens, two reviewers, without clinical information, independently assessed 55 specimens obtained following IRT and 39 control specimens obtained from nonirradiated cancer patients. None of the 24 cytologic features studied were identified significantly more frequently by both reviewers in the irradiated specimens. Only one feature (bizarre cells) was found to occur significantly more frequently in the irradiated specimens (36% versus 15%, P = .03) by either reviewer (reviewer B). Four other features showed a tendency to occur more frequently in the irradiated fluids by one or the other reviewer. They included degenerative changes (27% versus 13%, P = .09 [reviewer A]), smudgy chromatin (16% versus 5%, P = .09 [reviewer A]), large cytoplasmic vacuoles deforming the nuclei (44% versus 26%, P = .07 [reviewer B]) and cytomegaly (38% versus 23%, P = .12 [reviewer B]). The utility of these five features in identifying irradiated specimens was rigorously retested in a second masked review conducted jointly by the two pathologists. None of these features was found more frequently in the irradiated specimens in the second analysis. The results suggest that IRT does not consistently produce distinctive cytologic changes in pleural effusions and that a history of IRT should not affect the interpretation of these specimens.

Exudates and Transudates↗