Biomedical subjects

U Tylén

Publications and source records attributed to U Tylén.

At least 19 recordsLinked to original sources

PubMed2001

Neutrophil-associated activation markers in healthy smokers relates to a fall in DL(CO) and to emphysematous changes on high resolution CT.

Smoking is a risk factor for developing chronic obstructive pulmonary disease (COPD), but there are no good indicators for early identification of subjects who will develop symptomatic COPD. The aim of this study was to investigate inflammatory mechanisms related to changes in lung function and emphysematous changes on high resolution computed tomography (HRCT) in 'healthy' smokers. Subjects were 60-year-old men from a population study. Bronchoscopy was performed in 30 smokers and 18 who had never smoked. Blood tests, lung function measurements and HRCT were carried out in 58 and 34 subjects, respectively. In comparison with never-smokers, smokers had higher levels of myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein (ECP) and lysozyme in blood, higher levels of MPO, interleukin-8 (IL-8) and HNL in bronchial lavage (BL), and of IL-8, HNL and interleukin-lbeta (IL-1beta) in bronchoalveolar lavage (BAL). Smokers also had lower levels of Clara cell protein 16 (CC-16) in blood. HNL in BL and BAL showed strong correlations to other inflammatory markers (MPO, IL-8, IL-1beta). The variations in MPO in BL were explained by variations in HNL (R2 =0.69), while these variations in BAL were explained by variations in HNL and IL-1beta (R2 = 0.76). DL(CO) was the lung function variable most closely related to MPO and IL-8 in BL and BAL and to IL-1beta in BAL. In a multiple regression analysis, MPO, IL-1beta, IL-8 and CC-16 in BL and MPO in BAL contributed to the explanation of variations in DL(CO) to 41% and 22%. respectively, independent of smoking habits. In smokers with emphysematous lesions on HRCT, HNL in BAL correlated to emphysema score (r(s) = 0.71). We conclude that 'healthy' smoking men with a near normal FEV1 show signs of inflammation in the lower airways that are related to a decrease in DL(CO) and to emphysematous lesions on HRCT. This inflammation seems to be the result of both monocyte/macrophage and neutrophil activation.

Acute-Phase Proteins↗

PubMed2000

Emphysematous lesions and lung function in healthy smokers 60 years of age.

We aimed to study the occurrence of emphysematous lesions in symptom free smoking men of about 60 years of age and in a matching group of never-smoking men and the relationship between pulmonary changes at high resolution computed tomography (HRCT) and lung function tests. Our investigation included 57 smoking and 32 never-smoking healthy men from a randomized epidemiological study. HRCT was performed at full inspiration with a 1.5 mm slice thickness and a 3 cm inter-slice distance. Evaluation was made by two radiologists unaware of smoking history. Emphysematous lesions were scored visually. Pulmonary function tests were performed including spirometry and diffusion capacity test (DLCO). Emphysematous changes were demonstrated in 25 of 57 smokers but in only one never-smoker. DLCO/VA was the most sensitive test for early emphysematous lesions. It also correlated with radiographical scoring. Emphysematous lesions were evident in 44% of the healthy symptom free smokers. HRCT may reveal early emphysematous lesions in smokers before clinical symptoms have developed.

Cohort Studies↗

PubMed2000

Interventional treatment of gastrointestinal neuroendocrine tumours.

Neuroendocrine (NE) tumours of the gastrointestinal tract (carcinoids and endocrine pancreatic tumours) are rare diseases. In the presence of liver metastases these patients may suffer from disabling symptoms due to hormone overproduction. Patients with localized disease can be resected for cure and also patients with liver metastases can undergo potentially curative tumour resection. However, long-term follow-up of the latter cases indicates frequent recurrence of tumour. Using close biochemical monitoring of tumour markers combined with newer techniques for tumour visualization, these recurrences can often be diagnosed at an early stage so that repeat surgical procedures can be performed. During the last years very active surgery has been recommended for NE tumours, many of which have a relatively slow growth. Even in patients not amenable to curative liver surgery, debulking can be considered if the main tumour burden can be safely excised. The primary aim of this type of treatment is palliation of hormonal symptoms. An important question is whether the aggressive treatment actually prolongs survival. No prospective studies have been performed. Such studies are hampered by the lack of strict surgical programs running over long periods and the relative rarity of NE tumours. Liver transplantation may be another treatment modality in selected cases.

Biomarkers, Tumor↗

PubMed1999

[Spiral computed tomography--solution to diagnostic problems in pulmonary embolism?].

Clinical diagnosis of pulmonary embolism is difficult and often dependent on radiological methods. In Sweden scintigraphy has hitherto been the method most commonly used, though all too often it leaves the diagnosis in doubt. Spiral computed tomography, performed during continuous infusion of contrast medium, clearly depicts the pulmonaries arteries, emboli appearing as filling defects. The examination takes less than one minute. Although the method has yet to be fully evaluated, it is already available at most Swedish hospitals. Results presented so far suggest that the technique has great potential, and may become the method of choice in the diagnosis of pulmonary embolism.

Contrast Media↗

PubMed1999

Image quality for five modern chest radiography techniques: a modified FROC study with an anthropomorphic chest phantom.

The purpose of the study was to compare the image quality for one conventional and four digital chest radiography techniques. Three storage phosphor systems, one selenium drum system, and one film-screen system were compared using a modified receiver-operating-characteristics method. Simulated pathology was randomly positioned over the parenchymal regions and the mediastinum of an anthropomorphic phantom. Eight observers (four chest radiologists, one specialist in general radiology, one hospital physicist, and two radiographers) evaluated 60 images for each technique. The selenium drum system (Philips, Eindhoven, The Netherlands) rated best for the detection of parenchymal nodules. Together with the storage phosphor system of generation IIIN (Philips/Fuji), the selenium drum system also rated best for detection of thin linear structures. The storage phosphor system of generation V (Fuji) rated best for the detection of mediastinal nodules. The first generation of the storage phosphor system from Agfa (Mortsel, Belgium) rated worst for the detection of parenchymal nodules and thin linear structures. These differences were significant (p < 0.0001). Averaging the results for all test objects, the selenium drum system and the storage phosphor system of generation V were significantly better than the other systems tested. The film/screen system performed significantly better than the first-generation storage phosphor system from Agfa, equal to the generation IIIN storage phosphor system (Philips/Fuji) and significantly worse than the selenium drum system (Philips) and the generation-V storage phosphor system (Fuji). The conclusion is therefore that the image quality of selenium-based digital technique and of the more recent generations of storage phosphor systems is superior to both conventional technique and storage phosphor systems using image plates of older types.

Anthropometry↗

PubMed1998

Pulmonary edema following intravenous injection of nonionic low-osmolar contrast medium--appearance on HRCT. A case report.

Pulmonary edema following i.v. contrast medium injection is a rare adverse reaction. We report on a 71-year-old woman who developed pulmonary edema following i.v. injection of iohexol during spiral CT of the thorax. She developed shortness of breath during the injection, and the first radiographic signs of pulmonary edema were visible on CT images 25 s after the onset of injection. On HRCT images 15 min later, marked edema was demonstrated in both lungs in a mosaic pattern of distribution. After appropriate therapy, the patient recovered without sequelae. A repeat CT 6 days later showed complete normalization.

Aged↗

PubMed1997

Stimulable phosphor plates in chest radiology.

The stimulable phosphor plate technique has revolutionised radiology with portable equipment. The image quality permits diagnosis under difficult control conditions (ICUs). In order to achieve a signal-to-noise ratio, and therefore a contrast resolution similar to the commonly used film/screen systems, a higher radiation dose is needed. However, overall, with this technique a radiation dose reduction may be achieved as a result of the elimination of the need for retakes. The available stimulable phosphor plate systems, with adequate image processing are reliable, and at least as good as conventional film/screen systems for diagnosis in chest radiography. There are, however, other aspects that make the stimulable phosphor plate technique particularly appealing. Firstly, its reproducibility, which particularly in chest radiography allows images to be obtained with the same grey scale and darkness. Secondly, as this technique permits digital archiving and visualisation of images on screen, images can be rapidly distributed over a network making them available when and where they are needed.

Humans↗

PubMed1996

Treatment of liver metastases of carcinoid tumors.

Liver metastases imply a major problem in patients with carcinoid tumors. Patients with localized disease should always undergo resection for cure. Patients with distant metastatic disease can also undergo resection for potential cure or symptom palliation because of the slow growth rate of many carcinoid tumors. In patients with the midgut carcinoid syndrome and bilobar hepatic disease we have performed primary surgery to relieve such symptoms as intestinal obstruction and ischemia, followed by successive embolizations of the hepatic arteries to reduce functional tumor burden in the liver. For optimal palliation, all patients with residual tumor were treated by octreotide. In a consecutive series of 64 patients with the midgut carcinoid syndrome we thus attained a 5-year survival rate of 70%. Fourteen of the patients underwent intentionally curative surgery (e.g., primary surgery followed by liver surgery). Of these patients, none died from their tumor disease during the period of study. The value of adjunctive interferon therapy is currently under evaluation.

Antineoplastic Agents, Hormonal↗

PubMed1996

Survival of patients with disseminated midgut carcinoid tumors after aggressive tumor reduction.

Sixty-four consecutive patients with disseminated midgut carcinoids were treated during an 8-year period according to a single clinical protocol aimed at aggressive tumor reduction by surgery alone or with subsequent hepatic artery embolization. All patients had markedly elevated urinary 5-hydroxyindoleacetic acid (5-HIAA) levels (581 +/- 79 micromol/24 h) and hormonal symptoms. Fourteen patients (22%) reached anatomic and biochemical cure by surgery alone. At follow-up, the mean 5-HIAA levels were still normal after 69.0 +/- 6. 2 months; two patients had died from unrelated causes. With the introduction of somatostatin receptor scintigraphy, subclinical disease was diagnosed in 7 of these 14 patients. Forty patients with bilobar hepatic disease underwent embolization in combination with octreotide. In this group, 5-HIAA levels were still reduced by 55% after 71 +/- 11 months of follow-up, and the 5-year survival was 56%, estimated from the total death hazard function. After embolization, two subgroups could be identified with marked differences in their long-term response to treatment. Ten patients were not embolized owing to complicating diseases. The 5-year survival for the entire series was 58%. A significantly increased risk of cardiovascular deaths was seen, which underlines the importance of total survival analysis in a disease with multiple hormonal effects. It is concluded that an active surgical approach must be recommended to patients with the midgut carcinoid syndrome. In patients with bilobar hepatic disease, embolization combined with octreotide treatment markedly reduced the 5-HIAA excretion and suggested a prolonged 5-year survival.

Adult↗

PubMed1995

Digital chest radiography: clinical aspects.

Technical development puts the completely digital radiology department within reach. Presently available systems have slightly inferior spatial resolution than film/screen systems. This is well compensated for by image processing. In the future, the digital radiology department working environment will be different. Systems should be designed that conform as much as possible to radiologists' present way of working to facilitate transition to the new system and avoid unnecessary stress.

Humans↗

PubMed1995

Accumulation of natural killer cells after hepatic artery embolisation in the midgut carcinoid syndrome.

Eleven patients with disseminated midgut carcinoid tumour disease were subjected to hepatic artery embolisation. In six patients, lymphocytosis with a predominance of NK cells occurred and the cytotoxic activity of isolated lymphocytes increased. A relation between NK cell accumulation and subsequent radiological and biochemical response was observed, and it is suggested that anti-tumour mechanisms other than ischaemia may contribute to the therapeutic response in these patients.

Cytotoxicity, Immunologic↗

PubMed1995

Assessment of coronary artery stenosis during PTCA by measurement of the trans-stenotic pressure gradient. Comparison with quantitative coronary angiography.

A fibreoptic pressure sensor mounted on an 0.018 inch guidewire (Pressure Guide, RadiMedical Systems, Uppsala, Sweden) was used to measure the trans-stenotic pressure gradient in 20 patients admitted for percutaneous transluminal coronary angioplasty (PTCA) of a single, discrete stenosis. Pressure measurements were made both at rest and during maximal vasodilatation induced by intracoronary injection of papaverine. From the ratio of distal coronary pressure divided by the proximal pressure, the relative coronary flow reserve was calculated. The aim of the study was to compare the different pressure-derived parameters by correlating them to stenosis geometry estimated by quantitative coronary angiography. There was a moderate correlation between baseline pressure gradient and percent area stenosis; r = 0.64, P < 0.001 and minimal cross-sectional area; r = 0.45, P < 0.005. A higher correlation was found between hyperaemic pressure gradient and area stenosis (r = 0.80, P < 0.001) and minimal cross-sectional areas, respectively (r = 0.55, P < 0.005). The best correlation was found between relative coronary flow reserve and area stenosis (r = 0.86, P < 0.001) and minimal cross-sectional area (r = 0.70, P < 0.001). In conclusion, pressure measurement using a pressure guidewire is useful as a complement to angiography in evaluation of coronary stenoses during PTCA. Pressures should be measured during maximal vasodilatation. Relative coronary flow reserve calculated from the pressure measurements provides additional information about the fraction of normal maximal flow possible in the presence of a stenosis.

Aged↗

PubMed1993

Embolisation therapy in the midgut carcinoid syndrome: just tumour ischaemia?

Forty-eight patients with midgut carcinoid tumours and disseminated disease were treated at our unit 1986-1991. All patients underwent primary surgery with optimal tumour reduction. Twenty-seven patients with bilobar liver metastases had subsequent embolizations of the hepatic arteries to further reduce the functional tumour mass and were thereafter treated with a low dose of octreotide. The response to this treatment was evaluated by CT at 3 months postembolization. The patients could then be divided into 13 responders (no visible hepatic tumours or more than 50% reduction, group I) and 14 non-responders (less than 50 reduction or progression, group II). When these patients were studied biochemically and in terms of prognosis, the reduction of 5-HIAA levels postembolization was much more pronounced in group I (80 +/- 3%) then in group II (28 +/- 12%). The biochemical and radiological responses were long-lasting in group I, none of the patients needed further ischaemic treatment. Of specific interest were 3 patients with bilobar disease, who after selective unilobar embolisation normalised their 5-HIAA levels and had bilateral tumour regression. These findings indicate involvement of systemic effects in addition to tumour ischaemia alone. The initial biochemical response with marked decrease of 5-HIAA levels in combination with tumour regression may thus serve as an indicator of good prognosis.

Adult↗

PubMed1991

Chronic lower limb ischaemia. A prospective randomised controlled study comparing the 1-year results of vascular surgery and percutaneous transluminal angioplasty (PTA).

In a prospective randomised study, performed over a 6-year period, 102 patients with severe lower limb ischaemia or claudication resistant to exercise training were randomised either to percutaneous transluminal angioplasty (PTA) or vascular surgery. Only patients who could be treated by both methods were included, constituting only 5% of the total number of patients treated during this period. The two groups were similar regarding age, severity of symptoms and diabetes. The immediate and 1-year results showed similar success and complication rates. There was, however, a significantly shorter hospital stay for patients treated with PTA. Due to early complications and initial failures PTA should, however, only be used in institutions where vascular surgical facilities are available since PTA demands access to such treatment.

Adult↗

PubMed1991

Management of disseminated midgut carcinoid tumours.

Forty-one patients with disseminated midgut carcinoid tumours were treated over a 6-year period according to a strict programme including primary surgical treatment. In 10 patients, a total remission of the disease was obtained. Patients with bilobar hepatic disease had ischaemic treatment of their liver metastases by hepatic arterial embolisation after primary surgical and medical treatment (low dose octreotide). Thus, by combining surgical, radiological and medical treatment modalities, we wanted to offer these patients optimal palliation. This treatment programme resulted in good symptomatic relief in all patients accompanied by a marked reduction in 5-hydroxyindoleacetic acid (5-HIAA) levels. At recurrence of symptoms in combination with rising 5-HIAA levels, embolisation was repeated. Ten of the treated patients have deceased during the observation period, but only 5 from their carcinoid disease.

Adult↗

PubMed1991

Demonstration of hepatic veins by computed tomography using axial and angulated scanning.

The main hepatic veins run obliquely into the inferior caval vein. They are often poorly demonstrated on conventional axial computed tomography (CT) performed with a vertical gantry. In order to determine whether CT with caudal tilting of the gantry could improve demonstration of the hepatic veins, 30 consecutive patients of whom 20 had focal lesions in the liver were examined with both a vertical and a 20 degree caudally tilted gantry. As a reference group, 10 patients were examined with a 20 degree cranially tilted gantry. In 14/30 (47%) of the non-enhanced examinations caudally angulated CT demonstrated the hepatic veins better than axial CT, while axial CT was the better technique in one patient. No additional tumors were detected with either technique, but the caudal angulation improved the anatomical location of tumors due to a better demonstration of their relation to hepatic veins. CT with cranial angulation did not in any patient improve the demonstration of veins when compared to axial CT. Angulated CT also included examination with contrast enhancement using bolus technique. In 20 out of 27 (74%) examinations with a caudally tilted gantry and contrast enhancement considered optimal for tumor detection, veins containing contrast medium were depicted for an anatomical description. Caudally angulated CT is a non-invasive technique which should be performed in patients in whom liver resection is considered.

Hepatic Veins↗

PubMed1990

Comparison of non-enhanced, bolus enhanced, and delayed scanning techniques in computed tomography of hepatic tumours.

Non-enhanced, bolus contrast medium enhanced and 4 to 6 hours delayed computed tomography of the liver was performed in a prospective study of 53 patients. Forty patients had focal lesions, in 12 of these they were hypervascular. Contrast medium was administered as an initial bolus followed by a rapid injection of meglumine metrizoate (Isopaque Cerebral). The total iodine dose varied between 56 and 63 g, which gave an average increase in attenuation of 14 HU in normal parenchyma comparing delayed with non-enhanced scanning. Presence and extent of focal lesions were evaluated in a randomized and independent analysis by two radiologists. The percentage of examinations with correct tumour description was higher with bolus scanning (observer I 73%, observer II 75%) and delayed scanning (observer I 75%, observer II 78%) than with non-enhanced scanning (observers I and II 67%). An optimal bolus technique requires an exact timing of the contrast medium administration and scanning. Delayed scanning provides an excellent supplement when the bolus examination is suboptimal or shows equivocal findings.

Adult↗

PubMed1990

Contrast enhancement of liver parenchyma and biliary tract related to liver function at delayed computed tomography.

Computed tomography (CT) of the liver was performed in 53 patients before, during and 4 to 6 hours after intravenous administration of approximately 60 g of iodine in metrizoate. At delayed CT, contrast medium was observed in the extrabiliary ducts in 20 patients (38%) and in the gallbladder in 28 (68%) of the 41 patients with no previous cholecystectomy. The increase in attenuation of liver parenchyma at delayed CT compared with the non-enhanced baseline CT ranged between 2 and 26 HU (mean 13.9). The material was divided into three groups with regard to liver function: normal, intermediate and pathologic. In the normal group contrast medium was observed in the gallbladder in 81 per cent and in the bile ducts in 57 per cent and the mean increase in attenuation of the liver parenchyma was 14.5 HU. In the pathologic group the same parameters were 40 per cent, 7 per cent and 10.6 HU, respectively. Contrast medium in the gallbladder and biliary ducts improved the information about anatomy. Pathology of the gallbladder and tumour growth along the hepatoduodenal ligament were better demonstrated. Delayed CT is a simple and non-invasive technique that may improve planning of liver surgery.

Biliary Tract↗