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Biomedical subjects

E G Olsen

Publications and source records attributed to E G Olsen.

At least 73 records · Page 4Linked to original sources
PubMed1985

Coronary anatomy in patients with various manifestations of three vessel coronary artery disease.

The histology of coronary arteries was compared in patients with rest and effort angina. The arteries came from six patients with three vessel disease who died within four weeks of arteriography and ambulatory ST segment monitoring. Sections of all macroscopically visible arteries were taken every 5 mm and examined histologically. Episodes of ST segment depression had occurred on exertion in two patients, during exertion and rest (nocturnal) in two, and two patients had had no episodes of ST segment depression during ambulatory monitoring. Concentric (29%) or eccentric (62%) intimal thickening due to atheroma or fibroelastic tissue was found in 91% of sections. All but two normal intimal sections (1%) were found to be diseased in patients with ambulatory ST segment changes. Eccentric lesions with medial smooth muscle preservation in areas without intimal thickening, where further luminal narrowing could occur due to increases in smooth muscle tone, were found in 15% of sections. But these areas were not found in the proximal 3.5 cm of any of the major coronary arteries of the two patients with rest and effort ischaemia. Spasm could not have caused total occlusion in any of these arteries because the lumen was splinted by the lesion. There was no difference in mean luminal narrowing between patients with exertional and rest ischaemia and exertional ischaemia only (mean 74%), but mean luminal narrowing was lower in patients with no ambulatory episodes of ST segment change (39%). Thus medial smooth muscle spasm was unlikely to have caused occlusion in patients with ambulatory ST segment changes, although it could have altered lumen diameter. There are no histological differences in the coronary arteries of patients with rest or effort induced myocardial ischaemia.

Aged↗
PubMed1985

Role of calcium in the induction of cardiac hypertrophy and myofibrillar disarray. Experimental studies of a possible cause of hypertrophic cardiomyopathy.

The role of calcium in the pathogenesis of hypertrophic cardiomyopathy was investigated experimentally. For this purpose the calcium antagonist verapamil and the calcium ionophore A23187 were administered to pregnant rats together with triac in order to observe their effect on triac induced myocardial disarray and hypertrophy in developing rat hearts. At a low dose verapamil reduced both the level of disarray and hypertrophy, but a higher dose produced hypertrophy when given alone. A23187 did not appreciably potentiate the actions of triac when given in combination but when administered alone produced both disarray and hypertrophy. Verapamil prevents the inward movement of calcium ions to the myocardial cell, whereas A23187 increases the inflow of calcium ions. The results suggest that the actions of triac in producing myocardial disarray and hypertrophy are attributable to an increased concentration of intracellular calcium.

Animals↗
PubMed1985

The role of biopsy in the diagnosis of myocarditis.

Reference to the background of myocarditis since the early nineteenth century has been made to emphasize the problem of diagnosis of this condition which has been largely overcome by the introduction of the bioptome and morphological evaluation of the fresh endomyocardial biopsies obtained by these means. A definition and classification into active, healing and healed phases has been provided and constitutes a rational approach to therapy with corticosteroids and immunosuppressive agents. The observation that myocarditis is evident in biopsy tissue from patients suspected with dilated cardiomyopathy and additional virological and immunological investigations have shed light on a possible pathogenetic mechanism which in some patients with this condition is an infectious immunological process. In addition, when myocarditis in the active or early healing phases is found, it has been shown that therapy is beneficial to the patient. Myocarditis is also the initial morphological expression of endomyocardial disease associated with eosinophilia. The eosinophils are in addition morphologically abnormal in the form of degranulation. Examination of blood films and endomyocardial biopsies has defined the earliest form of this disease process and early treatment can also now be instituted. This up-to-date overview of our present state of knowledge has repeatedly demonstrated that biopsy examination in the diagnosis of myocarditis plays a vital role.

Biopsy↗
PubMed1985

[Histologically detectable myocarditis in patients with impaired left ventricular function].

In patients with impaired left ventricular function in whom dilated cardiomyopathy is initially suspected after performance of comprehensive diagnostic studies, histologic evidence of myocarditis or status-post myocarditis is being documented with increasing frequency since the systematic use of endomyocardial biopsy has been incorporated into the work-up. This investigation was undertaken to analyze the histologic, clinical, hemodynamic and immunologic findings in these patients to delineate possible relationships between histologically-documented myocarditis and dilated cardiomyopathy. Incidence of histologically-documented myocarditis. In our patient population, 41 of 150 patients with impaired left ventricular function, the etiology of which had been unknown, histologic evidence of myocarditis was documented. In seven of eight in whom active myocarditis was diagnosed at initial biopsy, after a mean follow-up period of two years the histologic findings were consistent with dilated cardiomyopathy. In similar groups of patients comparable incidences of myocarditis have been reported by Parrillo et al. in 19 of 100 (19%) and Fenoglio et al. in 34 of 135 patients (25%). A higher incidence has been reported by Zee-Cheng et al. in 22 of 35 patients (63%). Accordingly, pooled data indicate that the overall incidence of histologically-documented myocarditis was 30% in 528 patients initially suspected to have dilated cardiomyopathy. The variances in the incidence reported by the respective authors may be attributable to differences in the histologic definition of myocarditis, number of biopsies obtained, size of the patient population and the epidemiologically-related incidence of viral disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoantibodies↗
PubMed1984

The healing of rabbit corneal endothelium.

A circular 4 mm endothelial defect was induced by transcorneal freezing. The experimental damage and the healing took place in the living rabbit in 15 eyes, and in the isolated cornea in organ culture in further 20 eyes. The reparative process was studied by SEM, and proved to be the same in vivo and in vitro. The defect was covered with endothelial cells after 3 days. The normal hexagonal pattern was regained after 3 weeks. Both cell migration and cell division were involved in the reparative process. Only cells recruited from a zone close to the defect were active; the cells situated more than a few cell diameters from the original edge maintained their form and size unchanged. The first phase of cell division was the formation of a spherical cell with numerous blebs on its surface.

Animals↗
PubMed1984

The healing of human corneal endothelium. An in vitro study.

A 4 mm circular defect was made on the endothelium by transcorneal freezing of 5 normal human corneas. The eyes were enucleated because of malignant tumours, patient age 3 to 74 years. After excision, the corneas were kept in culture medium for 3 (4) days, and subsequently prepared for SEM. At this stage, the defect was covered with endothelium, whose origin was a narrow zone adjoining the edge of the defect. The endothelium on the peripheral, undamaged part of the cornea did not seem to take part in the repair process, neither by proliferation, enlargement nor by migration. Dividing cells were found scattered on the damaged area. The repair process was found to be similar in all five eyes, irrespective of the age of the patient. In organ culture, the healing of corneal endothelial defects is similar in rabbits and in humans.

Adult↗
PubMed1984

The effect of steroids on the healing of the corneal endothelium. An in vivo and in vitro study in rabbits.

The effect of steroids on the repair of a corneal endothelial defect in rabbits was studied by in vivo and by organ culture experiments. A standard 4 mm defect was produced by transcorneal freezing. The situation after 2, 3, and 4 days was studied by scanning electron microscopy. Preliminary experiments demonstrated that topical eye treatment influenced on the repair process of the untreated, contralateral eye. The preservants of commercial eye drops caused delayed healing in organ culture. These effects were excluded from the control experiments. Topical eye treatment with steroid eye drops for 3 days caused a one day delay in the repair process. In culture medium, delayed repair was found at hydrocortisone concentrations greater than or equal to 0.125 mg/ml. The visible influence of hydrocortisone increased with the concentration in the range examined, between 0.05 mg/ml and 1 mg/ml.

Administration, Topical↗
PubMed1984

On the spatial organization of the cornea endothelium.

A hexagonal pattern is formed by the apical aspects of the corneal endothelial cells. However, by electron microscopy of surface-parallel sections it can be seen that the basal part of these cells has a highly irregular shape with deep indentations and high ridges. Near the Descemet membrane numerous cytoplasmic processes are tangled together in a bewildering pattern. A few of these processes are exposed to the posterior surface, where they may be seen as small cell-like areas delineated by cell borders. The hexagonal apical pattern of the endothelium is related to minimum total length of the intercellular apical sealing. This pattern may develop by a minimizing process with analogy to the minimum surface formation of soap bubble film.

Animals↗
PubMed1984

A new method of determining the cell density from a corneal specular micrograph.

Non-contact specular micrographs of the corneal endothelium are usually only a few cell diameters in width. The oblong shape leads to uncertainties in the determination of cell density by counting the number of cells on an area of known size. A new method, particularly suited for a long and narrow picture, is described. A line with a length corresponding to 1 mm is drawn on a specular micrograph. The number n of cells sectioned by this line is counted. It is demonstrated that the average cell size A may be determined from n by the formula A = 1 404 669/n2 micron2. The relation between A and n is presented in Table 1, which also gives the corresponding cell density expressed by the number of cells per mm2.

Animals↗
PubMed1984

Acute myocarditis. Role of histological and virological examination in the diagnosis and assessment of immunosuppressive treatment.

Twelve patients, who presented with congestive cardiac failure after a recent influenza like illness, had a clinical diagnosis of acute myocarditis confirmed histologically after endomyocardial biopsy. Eight were under 30 years of age. Serological testing suggested a viral aetiology in six patients. Nine patients were treated with immunosuppressive drugs (prednisolone and azathioprine in seven, prednisolone alone in two). At two months, seven patients showed clinical and haemodynamic improvement (ejection fraction rose from 26.8 to 49% and left ventricular end diastolic pressure fell from 26.4 to 16.2 mm Hg) with biopsy evidence of healed myocarditis. In two, activity persisted. At six months' follow up only four of these patients had maintained their improvement. One patient relapsed after stopping treatment, subsequently improving on its reinstatement. Two patients developed severe interstitial myocardial fibrosis with gradual deterioration. Virology and myocardial histology were complementary in the diagnosis of acute myocarditis in these young patients, whose response to immunosuppressive treatment was variable. An apparent early response could not be clearly separated from variables in the natural history of the condition. Serial endomyocardial biopsies showed a progression to congestive cardiomyopathy in two patients. Multicentre controlled trials will be necessary to assess fully the role of immunosuppressive treatment in this condition.

Acute Disease↗
PubMed1983

Effect of triac and beta-adrenergic blocking agents on the myocardium of developing rats.

Triiodothyroacetic acid, triac, when given to rats during pregnancy, causes hypertrophy and intracellular disarray in the hearts of their offspring and concurrent treatment with dl propranolol can prevent the latter abnormality. Further experiments have been carried out to test the effect of dl oxprenolol and d propranolol on triac-induced myofibrillar disarray. Administration of dl oxprenolol at the same time as triac prevented disarray but a higher dose than that of dl propranolol was required to produce this effect. Disarray was also prevented by d propranolol. Selective consideration of the membrane stabilising, beta blocking and agonist activities of dl oxprenolol and d and dl propranolol leads to the conclusion that although direct or indirect beta stimulation by triac may play a small part in its disruptive effect on the developing myocardium, its main deleterious action can be blocked by membrane stabilisation.

Animals↗
PubMed1983

Anatomic and light microscopic characterisation of hypertrophic obstructive and non-obstructive cardiomyopathy.

Macroscopically asymmetric hypertrophy of the interventricular septum is the characteristic change, though mild degrees can be seen in normal hearts and in combination with congenital or acquired heart disease. If asymmetric hypertrophy is severe, this alone characterises the condition. Concentric forms have, however, been described. At light microscopic level disarray and often extreme hypertrophy of myocardial fibres together with degenerative changes and interstitial fibrosis are typical. Overlap of individual features with 'ordinary' hypertrophy exists but if all criteria are considered in combination a high degree of diagnostic reliability can be achieved, frequently aided by severe accumulation of glycogen. In support semiquantitative studies will also be presented. The patterns of abnormal fibre arrangement differ in the two clinical types. In cases with obstruction the abnormal fibres are predominantly confined to the interventricular septum, whereas in cases without obstruction they are scattered focally throughout the ventricular walls. Unfortunately, these disturbances are not always present. Subdivisions based on histological changes by other workers will be mentioned. Brief reference will be made to experimental work that has shown that a possible endogenous mechanism may be operative in some of the patients with hypertrophic cardiomyopathy. It is concluded that the morphology of hypertrophic cardiomyopathy is sufficiently characteristic to separate it as a distinct entity and to ensure reliable diagnosis.

Cardiomyopathy, Hypertrophic↗