| 1. |
- Tisell, Lars-Eric, 1931, et al.
(author)
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Somatostatin receptor scintigraphy in medullary thyroid carcinoma.
- 1997
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In: The British journal of surgery. - 0007-1323. ; 84:4, s. 543-7
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Journal article (peer-reviewed)abstract
- 111In-radiolabelled (DTPA-D-Phe1)-octreotide scintigraphy can be used to localize neuroendocrine tumours expressing somatostatin receptors (SSTRs). The aim of this paper was to analyse the importance of tumour volume and growth for the visualization by SSTR scintigraphy of metastases from medullary thyroid carcinoma (MTC).
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| 2. |
- Greiff, Lennart, et al.
(author)
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Effects of topical platelet activating factor on the guinea-pig tracheobronchial mucosa in vivo
- 1997
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In: Acta Physiologica Scandinavica. - 0001-6772. ; 160:4, s. 387-391
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Journal article (peer-reviewed)abstract
- Platelet activating factor (PAF) has been reported to produce a variety of airway effects including epithelial damage and increased airway-lung absorption of hydrophilic tracers. The present study examines effects of PAF on the guinea-pig tracheobronchial mucosa in vivo. Vehicle with and without PAF (4.0 and 8.0 nmol) was superfused onto the tracheobronchial mucosa. The levels of 125I-albumin, previously given intravenously, were determined in tracheobronchial lavage fluids as an index of mucosal exudation of plasma. The mucosa was also examined by scanning electron microscopy. In separate animals, 99mTc-DTPA (a low molecular weight, 492 Da, hydrophilic tracer) was superfused onto the mucosal surface through an oro-tracheal catheter, together with vehicle or PAF (8.0 nmol). A gamma camera determined the disappearance rate of 99mTc-DTPA from the airways as an index of mucosal absorption. PAF produced dose-dependent mucosal exudation of plasma up to 20-fold greater than control (P < 0.001). However, PAF did not damage the epithelium and the absorption ability of the airway mucosa was unaffected. The results, in contrast to previous reports, suggest that PAF may not readily damage the airway mucosa even at large exudative doses of the agent. The present finding support the view that the plasticity of the epithelial junctions allows the creation of valve-like paracellular pathways for unidirectional clearance of extravasated plasma into the airway lumen. We suggest that endogenous PAF may participate in first line respiratory defence reactions by causing lumenal entry of bulk plasma without harming the epithelium.
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| 3. |
- Ivancev, Krassi, et al.
(author)
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Abdominal aortic aneurysms: experience with the Ivancev-Malmo endovascular system for aortomonoiliac stent-grafts
- 1997
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In: Journal of Endovascular Surgery. - 1074-6218. ; 4:3, s. 242-251
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Journal article (peer-reviewed)abstract
- PURPOSE: To describe a component-based aortomonoiliac stent-graft system and the first clinical results achieved with this device in endovascular abdominal aortic aneurysm (AAA) repair. METHODS: From November 1993 to October 1996, 45 patients aged 60 to 86 years underwent endoluminal exclusion of true AAAs (median diameter 60 mm) involving the common iliac arteries (median diameter 16 mm right and 15 mm left) using unilimb stent-grafts deployed with the Iancev-Malmo system. RESULTS: Six immediate conversions occurred in the beginning of the series due to endografts that were too short. Complications, including 2 inadvertent renal artery occlusions, 7 kinked grafts, 6 iliac artery dissections, and 3 perioccluder leaks, were prominent features in the first 15 patients. Five patients died in the postoperative period, four of whom were nonsurgical candidates. There were five significant stent-graft migrations: one 3 weeks after surgery due to mechanical injury of the proximal stent and four after 1 year owing to continuous dilation of a wide proximal neck, stent-graft placement in a conical, thrombus-lined proximal neck, and two instances of proximal extension separation from the main graft. Translumbar aneurysm perfusion required embolization in 3 patients. CONCLUSIONS: Despite early complications associated with a learning curve, exclusion of large AAAs using unilimb stent-grafts is feasible. Strict inclusion criteria are necessary in order to improve mortality among nonsurgical candidates and minimize the risk for late migration.
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| 4. |
- Karlsson, M K, et al.
(author)
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Remodeling of the spinal canal deformed by trauma
- 1997
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In: Journal of Spinal Disorders. - 0895-0385. ; 10:2, s. 157-161
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Journal article (peer-reviewed)abstract
- Computed tomography (CT) examinations and functional scores were evaluated in 28 patients with thoracolumbar fractures with intraspinal fragments, of whom 20 underwent operation. The cross-sectional area and the sagittal and frontal diameters of the spinal canal were measured after the injury, postoperatively, and at follow-up (mean, 6 years). The operative reduction significantly increased both diameter and area of the spinal canal. During follow-up, a further significant increase of the sagittal diameter and the area was noted, in both surgically and conservatively treated patients. There was no difference in remodeling between the groups. Six patients in the surgically treated group had neurologic deficits at admission, five had improved, and one remained unchanged at follow-up. The presence or absence of intraspinal fragments should not influence the treatment strategy per se in cases without neurologic signs.
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| 5. |
- Malina, Martin, et al.
(author)
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Changing aneurysmal morphology after endovascular grafting: relation to leakage or persistent perfusion
- 1997
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In: Journal of Endovascular Surgery. - 1074-6218. ; 4:1, s. 23-30
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Journal article (peer-reviewed)abstract
- PURPOSE: To relate changing abdominal aortic aneurysm (AAA) morphology after endovascular grafting to the presence of leakage, collateral perfusion, and other factors. METHODS: Thirty-five patients who underwent successful AAA endovascular grafting were evaluated. Self-expanding Z-stents and Dacron grafts were applied in bifurcated and aortomonoiliac systems. Postoperative diameter changes were calculated from repeated spiral computed tomographic scans, angiograms, and ultrasonic phase-locked echo-tracking scans during a median 6-month follow-up (interquartile range [IQR] 3 to 12). RESULTS: At 12 months, the diameters of completely excluded aneurysms had decreased 6 mm (IQR 2 to 11; p = 0.006). The proximal graft-anchoring stents had dilated 2 mm (IQR 0.5 to 3.3; p = 0.01). The aortic diameters immediately below the renal arteries but above the stents had not changed. Endoleakage and collateral perfusion (n = 13) were each associated with preserved aneurysm size and a 12 times higher risk of aneurysm dilation. After the leakage or the collateral perfusion had been treated, the aneurysm size decreased. Aneurysms with extensive intraluminal thrombi presented a reduced risk of leakage or perfusion. CONCLUSIONS: The diameters of endovascularly excluded AAAs decrease, except in cases of leakage or perfusion. Careful follow-up of patients with aortic endografts is necessary.
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| 8. |
- Ahlman, Håkan, 1947, et al.
(author)
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The relevance of somatostatin receptors in thyroid neoplasia.
- 1997
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In: The Yale journal of biology and medicine. - 0044-0086. ; 70:5-6, s. 523-33
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Journal article (other academic/artistic)abstract
- 111In-octreotide scintigraphy in patients with persistent medullary thyroid carcinoma (MTC) visualized tumors in about half of the surgically explored sites. Tumor visualization correlated with rapid tumor growth and large tumor volume as judged from calcitonin levels. The 111In concentration ratio between tumor (T) and blood (B) in surgically excised lymph node metastases of MTC showed a large variation, with low values for microscopic and high values for macroscopic metastases in individual patients. Three cases of MTC, Hürthle cell adenoma and papillary thyroid cancer are reported with preoperative scintigraphy, T/B ratios and Northern analyses of the surgical biopsies. Visualization of tumors was possible in the absence of sstr2 (the high affinity receptor for octreotide) with the exception of microscopic tumor growth. T/B values in the patient with Hürthle cell adenoma were similar to those found in the contralateral thyroid lobe with goitre. The relatively high uptake of 111In in benign thyroid conditions probably limits the use of octreotide scintigraphy in the diagnosis of primary tumors. The technique has certain advantages over radioiodine scintigraphy after the surgical treatment of thyroid tumors: no need for withdrawal of thyroxin substitution; a possibility to diagnose metastases of tumors that do not concentrate radioiodine (MTC, Hürthle cell cancer); and complementary information about metastatic sites of non-medullary thyroid cancer (papillary and follicular tumors).
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| 9. |
- Nilsson, Kristina
(author)
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Solute exhange across the alveolo-capillary barrier.
- 1997
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Doctoral thesis (other academic/artistic)abstract
- The aim of this thesis was to study the transfer of solutes across the alveolo-capillary barrier in experimental models of alveolar surfactant dysfunction and lung injury as well as in smokers. Experimental studies were performed in anaesthetized, and mechanically ventilated animals. Surfactant dysfunction was induced by administration of a synthetic detergent in aerosol form. Lung injury was induced by intravenous injection of oleic acid. A range of radiolabelled solutes were administrered in aerosol form and the clearance of the tracer from the lungs measured with a gamma camera. Detergent administration results in mild pulmonary oedema and has little effect on compliance of the respiratory system and gas exchange. Oleic acid administration produces severe oedema, reduces compliance and impairs gas exchange. The increase in pulmonary clearance of a small, hydrophilic solute was greater after detergent administration than after injection of oleic acid. Surfactant dysfunction dramatically increased the clearance of small, hydropholic solutes, but had little effect on albumin or on small, lipophilic solutes. The effect of detergent administration on clearance of a small, hydrophilic solute could be partly reversed by administration of natural surfactant. The effect of smoking on clearance of small and large solutes was studied in normal subjects. The effect of smoking was qualitatively similar, but the differences between smokers and non-smokers were greater for the small than for the large solute. The studies provide further evidence that the alveolar surfactant system forms part of the alveolo-capillary barrier against exchange of small, hydrophilic solutes. Clearance of larger solutes may to a greater extent reflect the properties of the structural components of the alveolo-capillary barrier.
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| 10. |
- Wirestam, Ronnie
(author)
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Nuclear magnetic resonance and microcirculation: The influence of pulsatile brain-tissue motion on measurements of intravoxel incoherent motion and assessment of haemodynamics using exo- and endogenous tracers
- 1997
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Doctoral thesis (other academic/artistic)abstract
- In this project, the potential of magnetic resonance (MR) imaging and spectroscopy in studies of microcirculation and haemodynamics was evaluated. The spatial and temporal characteristics of human pulsatile brain-tissue movements in healthy individuals, relevant for the understanding of the cerebrospinal-fluid (CSF) circulation and the pathogenesis of hydrocephalus, were thoroughly investigated. Abnormal motion patterns in brain tissue and CSF were demonstrated in patients with intracranial tumours, and navigator echoes were shown to reduce motion artifacts in phase images. Intravoxel phase dispersion, caused by a spatial distribution of brain-tissue velocities, was shown to act as a source of uncertainty in gradient-sensitised MR imaging of intravoxel incoherent motion (IVIM). The diffusion coefficient was considerably overestimated if measured during inappropriate periods in the cardiac cycle, a finding which may also prove important in IVIM-encoded echo-planar imaging (EPI). Using IVIM-sensitive EPI, the perfusion fraction in patients with acute ischaemic stroke was shown to be considerably smaller in the infarct region than in normal tissue in the contralateral hemisphere. In a deuterium MR spectroscopy study, the D2O washout in animals, after intratissue injection, displayed a pronounced injection-volume dependence as well as a non-physiological component of signal decay. The reproducibility was reasonable in subcutaneous tissue, but rather poor in heterogeneous tumours. In a dynamic susceptibility-contrast MR imaging study, the first passage of an exogenous tracer (Gd-DTPA- BMA) was monitored in the normal human brain, and reasonable regional cerebral blood volume (rCBV) values were observed. The rCBV and the perfusion fraction in white matter showed a promising tendency to correlate. Finally, functional MR imaging (fMRI) studies of cortical activation were initiated in a typical clinical environment, and it was verified that cortical activation is observable both at 1.0 T and 1.5 T. Investigations of the field-strength dependence might, to some extent, provide information on the origin of the fMRI contrast in gradient-echo imaging.
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