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Biomedical subjects

A Magnusson

Publications and source records attributed to A Magnusson.

At least 55 records · Page 3Linked to original sources
PubMed1999

Intrusion into patient privacy: a moral concern in the home care of persons with chronic mental illness.

The aim of this study was to identify and analyse ethical decision making in the home care of persons with long-term mental illness. A focus was placed on how health care workers interpret and deal with the principle of autonomy in actual situations. Three focus groups involving mental health nurses who were experienced in the home care of persons with chronic mental illness were conducted in order to stimulate an interactive dialogue on this topic. A constant comparative analysis of the transcribed audiotaped sessions identified a central theme that concerned the moral symbolic meaning of 'home'. This reflected the health care workers' conflict between their professional role and their moral role, which they perceived as unclear.

Chronic Disease↗
PubMed1998

[Autosomal dominant nocturnal frontal lobe epilepsy. An electroclinical and genetic description of a Norwegian family with ten affected members].

We describe a Norwegian family with clusters of brief nocturnal motor seizures with hyperkinetic or tonic manifestations. Seizures started in childhood. Neurological examination and neuroimaging were normal. Interictal EEG registrations were mostly normal, ictal EEG registrations disclosed left frontal epileptiform discharges in two of three patients examined and just shallow arousal preceding the attack in one of the three patients. Segregation analysis indicated an autosomal dominant inheritance pattern, and the patients were subsequently diagnosed as having autosomal dominant nocturnal frontal lobe epilepsy, a disorder first described in 1995. A missense mutation in the gene for the alpha-4 subunit of the neuronal nicotinergic acetylcholine receptor was recently described in an Australian family with this disorder. Our Norwegian family proved to have a novel insertion mutation (776ins3) in the same gene. This mutation affects the second transmembrane domain (M2) which forms the critical section of the ion channel. This is the first case of idiopathic partial epilepsy where the underlying molecular defect has been found. The fact that a dysfunction of the nicotinergic acetylcholine receptor may give rise to frontal epileptic seizures was surprising and may shed new light on the basic mechanisms of epileptogenesis. Manipulations of the cholinergic system may open up a new therapeutic approach.

Adolescent↗
PubMed1998

The efficacy of FP 736-04 in experimental liver cirrhosis.

PURPOSE: To determine whether the uptake of FP 736-04, a hepatocyte-specific CT contrast agent, is influenced by cirrhotic changes in the liver. MATERIAL AND METHODS: Liver cirrhosis was induced by bile duct ligation (BDL) in Sprague-Dawley rats. Seventy-four animals were divided into three groups comprising: rats with acute BDL; rats with chronic BDL; and normal controls. CT was performed after i.v. infusion of FP 736-04 or saline at a dose of 2 ml/kg b.w., and the mean attenuation in the liver and spleen was measured. The livers from the chronic BDL group were taken for histopathological examination and the extent of the disease was graded according to an arbitrary scale. RESULTS AND CONCLUSION: There was a significant reduction of the native liver attenuation in both chronic and acute BDL groups as compared with the normal controls. FP 736-04 was taken up by the liver parenchyma with a similar degree of enhancement in all three groups.

Animals↗
PubMed1998

Detecting experimental liver metastases at CT with the hepatocyte-specific contrast medium FP 736-03.

PURPOSE: To evaluate the detection of experimental hepatic metastases at CT with the hepatocyte-specific contrast medium FP 736-03. MATERIAL AND METHODS: A nude-rat model of experimental multiple hepatic metastases from a human colonic cancer was used. Three weeks after intraportal tumour cell injection, the CT examination was performed before and after i.v. injection of FP 736-03 at a dose of 0.5 ml/kg b.w. RESULTS: The overall detection rate was determined in a lesion-by-lesion analysis of 87 metastases. Irrespective of metastatic size, the mean detection rate for two viewers was significantly higher at the FP-736-03-enhanced examination (59%) than at the unenhanced CT examination (16%). CONCLUSION: The detection rate increased with the i.v. administration of FP 736-03 at a dose of 0.5 ml/kg b.w. compared with that at unenhanced examination.

Adenocarcinoma↗
PubMed1998

Dynamics of lung collapse and recruitment during prolonged breathing in porcine lung injury.

Oleic acid (OA) injection, lung lavage, and endotoxin infusion are three commonly used methods to induce experimental lung injury. The dynamics of lung collapse and recruitment in these models have not been studied, although knowledge of this is desirable to establish ventilatory techniques that keep the lungs open. We measured lung density by computed tomography during breath-holding procedures. Lung injury was induced with OA, lung lavage, or endotoxin in groups of six mechanically ventilated pigs. After a stabilization period, repetitive computed tomography scans of the same slice were obtained during prolonged expirations with and without positive end-expiratory pressure and during prolonged inspirations after 5 and 30 s of expiration. Lung collapse and recruitment occurred mainly within the first 4 s of breath-holding procedures in all three lung injury models, and some collapse and recruitment occurred even within 0.6 s. OA-injured lungs were significantly more unstable than lungs injured by bronchoalveolar lavage or endotoxin infusion. In this experimental setting, expiration times <0.6 s are required to avoid cyclic alveolar collapse during mechanical ventilation without extrinsic positive end-expiratory pressure.

Animals↗
PubMed1998

Effect of different pressure levels on the dynamics of lung collapse and recruitment in oleic-acid-induced lung injury.

The effects of different inspiratory and expiratory airway pressures (Paw) on the dynamics of lung collapse and recruitment were studied in 14 anesthetized, mechanically ventilated, pigs with oleic-acid-induced lung injury. Repetitive CT scans of the same slice were obtained every 0.8 s during different inspiration and expiration hold procedures. The mean lung density and amount of atelectasis were measured in each scan. Inspiration to a Paw of 15 cm H2O above PEEP resulted in recruitment of collapsed lung tissue, mainly within 1.4 s. During expiration lung density increased rapidly and at an almost even rate within the first 1.4 s, whereas a rapid increase of atelectasis occurred after an initial delay period of 0.6 s with PEEP = 10 or 15 cm H2O. PEEP of 20 or 25 cm H2O almost prevented lung collapse during expiration. Thus, in order to avoid cyclic alveolar collapse during mechanical ventilation in oleic-acid-induced lung injury, a PEEP level >= 20 cm H2O or an expiration time <= 0.6 s is required. Long inspiratory time intervals, as used in inverse ratio ventilation, seem to be of minor importance for the recruitment of collapsed lung tissue in this experimental model.

Analysis of Variance↗
PubMed1998

Light therapy to treat winter depression in adolescents in Iceland.

OBJECTIVE: To determine whether light therapy during winter is beneficial to adolescents with symptoms of seasonal affective disorder (SAD). SETTING: The 3 largest colleges in Reykjavik, Iceland. PARTICIPANTS: Eighteen college students, 18 and 19 years old, suffering from symptoms of SAD. OUTCOME MEASURES: School attendance and self-reported change in indicators (concentration, ability to awaken in the morning, and frequency of breakfast). RESULTS: Light therapy helped some of the students concentrate and wake up in the morning, usually only to a mild degree, but did not improve school attendance. CONCLUSIONS: The lack of effect of light therapy on school attendance in a group of students with symptoms of SAD indicates that school attendance is influenced by several complex factors, of which seasonal disorders are not a major determinant, even in those most at risk.

Adolescent↗
PubMed1997

Internal consistency of the Seasonal Pattern Assessment Questionnaire (SPAQ).

We examined the consistency reliability of the widely used Seasonal Pattern Assessment Questionnaire (SPAQ). In total, 587 questionnaires from a random sample of the general population were analysed. The 6 items of the Seasonality Scale Index (SSI) correlated fairly well, and consequently this scale proved to have a high internal consistency (alpha = 0.82). Items from the SSI that measure seasonal variations in sleep and weight were consistent with other SPAQ scales that also measure these dimensions. Since the questionnaires analysed were from an epidemiological study, the high consistency reliability shows that the symptoms probed for by the SSI, tend to cluster in susceptible individuals in the general population.

Adolescent↗
PubMed1997

Relationship between contrast enhancement and diagnostic accuracy with the liver-specific CT contrast medium FP 736-04 in an experimental model of liver metastases.

RATIONALE AND OBJECTIVES: The authors sought to establish the optimal level of liver enhancement at computed tomography (CT) with a hepatocyte-specific contrast medium in an experimental model of liver metastases. MATERIALS AND METHODS: Anesthetized nude rats (n = 18) injected intraportally with cells from human colonic adenocarcinoma and Sprague-Dawley rats (n = 11) without metastases were used. A fractional intravenous infusion of contrast material was given in escalating doses up to a total of 4.0 mL per kilogram of body weight. Mean attenuation of the liver was calculated for each accumulated dose, and the overall detection rate was determined on a lesion-by-lesion basis. Sensitivity, specificity, and positive and negative predictive values were also established for each dose. RESULTS: Liver metastases were diagnosed with increasing reliability for enhancement values of up to 30.0 HU +/- 5.2 (mean +/- standard deviation), which corresponded to a dose of 0.5 mL/kg. CONCLUSION: In this model, optimal reliability in the diagnosis of liver metastases with CT was achieved at an enhancement value of approximately 30 HU.

Adenocarcinoma↗
PubMed1997

Effect of temperature history on the freeze-thawing process and activity of LDH formulations.

PURPOSE: The purpose of the study was to investigate the effect of freeze-thawing processes with different temperature histories on thermal transformations and on protein activity of lactate dehydrogenase (LDH) formulations. Polyethylene glycol (PEG 6000) and maltodextrin were used as cryoprotectants. METHODS: The thermal characterization was made by oscillating DSC (ODSC). LDH activity assays were performed spectrophotometrically. RESULTS: The crystallization of the solutions and the melting of the frozen samples occurred at fairly constant heat of crystallisation and heat of fusion values and temperatures. The main difference between the two investigated temperature cycles was an exothermic peak at -45 degrees C, which might reflect the transition between the cubic and hexagonal ice structures. When PEG was added to the system an additional endothermic peak appeared at -15 degrees C in the heating program. It was transformed into the shape of a glass transition at the same temperature when the heating rate was increased. The degree of crystallinity of the samples was evaluated as the quota between the Cp component of heat of transformation and the total heat of transformation values. Only minor differences between the two temperature histories and between the samples were observed. The cp component of the melting endotherm revealed a complex melting process with two overlapping endothermic transformations. The good protein protecting ability of PEG obtained when cooling and heating rate was low, was greatly reduced with increasing rate. The addition of maltodextrin to PEG-containing solutions lowered the activity recovery. CONCLUSIONS: The endothermic transformation of a PEG-ice structure at -15 degrees C in the heating process is strongly correlated to the protective ability of PEG 6000 in the freeze-thawing process of LDH. To obtain the highest protein activity after the freeze-thawing process, the formulation shall be transformed by a low cooling and heating rate. The crystallinity of the system melting at about 2 degrees C is independent of temperature history. The cp component of the melting endotherm, however, shows a complex transformation, where two phases of different crystallinity and stability might be involved.

Calorimetry, Differential Scanning↗
PubMed1997

An iodinated lipid emulsion for CT of the liver. Comparison with iohexol in the detection of experimental hepatic metastases.

PURPOSE: The iodinated hepatocyte-specific lipid emulsion FP 736-03 for CT of the liver was tested against the conventional water-soluble contrast agent iohexol. MATERIAL AND METHODS: A nude rat model of experimental multiple hepatic metastases from a human colonic cancer was used. The animals were examined 3 weeks after intraportal tumor cell injection. Native examination, and iohexol- and FP-736-03-enhanced CT were performed. The detection rate was determined on a lesion-by-lesion basis. Metastatic diameters measured on CT images were compared with corresponding macroscopic serial liver specimens. RESULTS: In a lesion-by-lesion analysis of 140 metastases, the detection rates for 2 viewers were 16.4% and 30.7% for native examination, 12.9% and 17.9% for iohexol-enhanced CT, and 53.6% and 72.1% for FP-736-03-enhanced CT, respectively. The detection rates tended to increase with lesion diameter. CONCLUSION: The hepatocyte-specific contrast medium FP 736-03 improved the detection rate significantly in comparison with both native and iohexol-enhanced CT.

Animals↗
PubMed1997

CT of experimental hepatoma using the hepatocyte-specific lipid emulsion FP 736-03.

PURPOSE: The aim of the study was to investigate whether moderately to well differentiated hepatocellular carcinomas (HCC) possess the same ability to take up a new lipid emulsion contrast medium, FP 736-03, as do hepatocytes. MATERIAL AND METHODS: A rat model of an experimental HCC was used. CT was performed before and after an i.v. bolus injection of 1.0 ml FP 736-03/kg b.w. Attenuation values of normal liver parenchyma and tumour tissue were measured over time. RESULTS: The contrast medium was taken up by the normal liver parenchyma but not by the tumour tissue for which the attenuation remained virtually constant over the observation period. CONCLUSION: The study demonstrated that FP 736-03 was not taken up by the HCC, thus producing a high lesion-to-liver contrast.

Animals↗
PubMed1997

CT with the hepatocyte-specific contrast medium FP 736-04 in an experimental model of liver steatosis.

PURPOSE: To investigate whether liver uptake of the iodinated hepatocyte-specific lipid emulsion FP 736-04 is altered by fatty infiltration of the liver. MATERIAL AND METHODS: Fatty infiltration of the liver was induced in female Sprague-Dawley rats by an intraperitoneal injection of L-ethionine preceded by 15 h of food withdrawal. CT of the liver was performed before and 24 h after the administration of L-ethionine and, in addition at the latter time point, after an i.v. injection of 1.0 ml/kg b.w. of FP 736-04. A control group was subjected to the same CT examination protocol. RESULTS: Intraperitoneal administration of L-ethionine caused liver steatosis, as established by liver triglyceride analysis, leading to a significant decrease in the liver attenuation, from 69.2 +/- 2.4 to 27.8 +/- 12.0 HU. The uptake of FP 736-04 by the fatty liver was significantly reduced, yielding a maximum enhancement of 22.3 +/- 7.9 HU as compared to a value of 32.3 +/- 5.0 HU in the control group. CONCLUSION: Enhancement by FP 736-04 was reduced in the steatotic liver compared with the normal liver. It remains to be established whether this degree of enhancement is sufficient for reliable lesion detection.

Animals↗
PubMed1997

CT with different doses of the hepatocyte-specific contrast medium FP 736-03. Evaluation in a nude-rat model of experimental metastases.

PURPOSE: To study the dose-response relationship in FP 736-03 (48 mg I/ml), hepatocyte-specific contrast medium for CT of the liver. MATERIAL AND METHODS: A nude-rat model of experimental hepatic metastases was used. CT of the liver was performed before and after i.v. injection of FP 736-03 at 4 different doses: 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. Attenuation in the normal liver parenchyma and in the metastases was measured and plotted as a function of time. RESULTS: The enhancement of the normal liver parenchyma increased in the dose range studied. No increase was found in the metastases: the attenuation here remained constant during the observation period. The maximum enhancement values at doses of 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. were (mean +/- SD) 13.5 +/- 2.7, 30.1 +/- 4.2, 33.2 +/- 4.5 and 59.7 +/- 13.1 HU respectively.

Adenocarcinoma↗
PubMed1997

Ropivacaine 0.75% for extradural anaesthesia in elective caesarean section: an open clinical and pharmacokinetic study in mother and neonate.

In an open study we have investigated the efficacy of 20 ml of 0.75% ropivacaine (7.5 mg ml-1) to provide extradural anaesthesia for elective Caesarean section. Plasma concentrations (total and free) were estimated in the mother and neonate. Anaesthesia was effective and safe. Plasma concentrations of ropivacaine in the mother and neonate were within safe limits and consistent with previous studies. Two mothers received accidental i.v. injections of ropivacaine 75 mg and 150 mg, respectively, without serious adverse effects.

Adult↗
PubMed1997

An insertion mutation of the CHRNA4 gene in a family with autosomal dominant nocturnal frontal lobe epilepsy.

Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is the first, and to date only, idiopathic epilepsy for which a specific mutation has been found. A missense mutation in the critical M2 domain of the alpha4 subunit of the neuronal nicotinic acetylcholine receptor (CHRNA4) has been recently identified in one large Australian pedigree. Here we describe a novel mutation in the M2 domain of the CHRNA4 gene in a Norwegian family. Three nucleotides (GCT) were inserted at nucleotide position 776 into the coding region for the C-terminal end of the M2 domain. Physiological investigations of the receptor reconstituted with the mutated CHRNA4 subunit reveal that this insertion does not prevent the receptor function but increases its apparent affinity for ACh. In addition, this mutant receptor shows a significantly lower calcium permeability that, at the cellular level, may correspond to a loss of function. Comparison of the two mutations identified so far in families with ADNFLE illustrates that different mutations can result in similar phenotypes.

Amino Acid Sequence↗