Biomedical subjects

G Karlsson

Publications and source records attributed to G Karlsson.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Deep vein thrombosis incidence at Akureyri Hospital, Iceland 1975-1990. Long term prognosis.].

OBJECTIVE: To evaluate the incidence of deep vein thrombosis (DVT) in a rural area of Iceland and the prevalence of post thrombotic syndrome (PTS) in patients with history of DVT. MATERIAL AND METHODS: A retrospective study where all phlebographies (n=177) performed at the department of radiology, Akureyri Hospital, during the period 1975-1990 were re-evaluated. Information on patients with DVT (n=32) were taken both from the Hospital and the Health Center records. All patients alive in December 1997 (n=17), 10.5 years after the diagnosis of DVT were interviewed concerning PTS. RESULTS: The incidence of DVT during the period 1975-1990 was 1/10,000 inhabitants/year, but was 2.3/10,000/ year for the period 1986-1996. The mean age was 60 years and 62% of the patients were males. In 37.5% cases DVT was localized below the popliteal vein, in another 34.4% below the inguinal ligament and 28.1% of the thrombosis extended to the pelvic vein system. Of the patients 23.3% had a history of malignancy and 20% had undergone a major operation or had trauma. Of the patients 46.7% were smokers. At 10.5 years follow-up, 71% of the patients had some problems due to PTS, and these symptoms influenced significantly their quality of daily life. CONCLUSIONS: The prevalence of DVT in Iceland seems to be only half of what foreign studies suggest and patients with history of DVT suffer frequently from PTS 10 years after the DVT. These data indicate that it is necessary to improve the long term treatment of patients with history of DVT.

English Abstract↗

PubMed1999

A multi-step lipid mixing assay to model structural changes in cationic lipoplexes used for in vitro transfection.

Formation of liposome/polynucleotide complexes (lipoplexes) involves electrostatic interactions, which induce changes in liposome structure. The ability of these complexes to transfer DNA into cells is dependent on the physicochemical attributes of the complexes, therefore characterization of binding-induced changes in liposomes is critical for the development of lipid-based DNA delivery systems. To clarify the apparent lack of correlation between membrane fusion and in vitro transfection previously observed, we performed a multi-step lipid mixing assay to model the sequential steps involved in transfection. The roles of anion charge density, charge ratio and presence of salt on lipid mixing and liposome aggregation were investigated. The resonance-energy transfer method was used to monitor lipid mixing as cationic liposomes (DODAC/DOPE and DODAC/DOPC; 1:1 mole ratio) were combined with plasmid, oligonucleotides or Na(2)HPO(4). Cryo-transmission electron microscopy was performed to assess morphology. As plasmid or oligonucleotide concentration increased, lipid mixing and aggregation increased, but with Na(2)HPO(4) only aggregation occurred. NaCl (150 mM) reduced the extent of lipid mixing. Transfection studies suggest that the presence of salt during complexation had minimal effects on in vitro transfection. These data give new information about the effects of polynucleotide binding to cationic liposomes, illustrating the complicated nature of anion induced changes in liposome morphology and membrane behavior.

4-Chloro-7-nitrobenzofurazan↗

PubMed1999

Separation of oxidized and deamidated human growth hormone variants by isocratic reversed-phase high-performance liquid chromatography.

Reversed-phase high-performance liquid chromatography (RP-HPLC) was utilized for the separation of recombinant human growth hormone (hGH) variants on a C18 silica column at 55 degrees C using an isocratic mobile phase which contained 27% 1-propanol in a 25 mM potassium phosphate buffer, pH 6.5. Three of the obtained peaks were characterized by tryptic mapping and mass spectrometry; two of the peaks were found to contain oxidized hGH (dioxy Met14/Met125 and Met125 sulfoxide) while the third contained a deamidated form (Asn149-->Asp149 or Asn152-->Asp152). Compared to the European Pharmacopoeia RP-HPLC method of hGH analysis, this new method gives two additional peaks and a 50% reduction in the analysis time.

Amides↗

PubMed1999

IgE-mediated reactions and hyperreactivity in pregnancy rhinitis.

OBJECTIVES: To determine whether respiratory allergy or hyperreactive nasal mucosa is exceptionally common in women with pregnancy rhinitis, and to evaluate other possible risk factors such as clinical asthma or rhinitis, smoking, age, parity, and sex of the child. PATIENTS AND METHODS: From an antenatal questionnaire study, 165 women, 83 (50%) of whom had had pregnancy rhinitis, were examined 6 months after delivery, and multiple antigen simultaneous testing chemiluminescent assay (MAST CLA) (10 airborne allergens) was performed. After histamine provocations, rhinostereometry and acoustic rhinometry were performed in 25 of them. Serum levels of soluble intercellular adhesion molecule-1 were determined 4 times during and once after pregnancy in 5 women with pregnancy rhinitis and 17 without pregnancy rhinitis. RESULTS: Thirty-nine women (24%) were sensitized to 1 or more allergen. The pregnancy rhinitis group showed significantly higher levels of IgE to house dust mites. There were also more smokers in the pregnancy rhinitis group. Clinical asthma or rhinitis, age, parity, and sex of the child did not differ significantly between the 2 groups. Mucosal swelling increased with rising concentrations of histamine, as measured with rhinostereometry, but there was no significant difference between the 2 groups in any of the variables. Serum soluble intercellular adhesion molecule-1 was not elevated in the pregnancy rhinitis group. CONCLUSIONS: This study found no increased frequency of allergy in general in women who have had pregnancy rhinitis. However, IgE against house dust mite was more frequent in the pregnancy rhinitis group. Smoking seems to be a risk factor, but age, parity, sex of the child, and hyperreactive nasal mucosa do not. Soluble intercellular adhesion molecule-1 was not elevated during pregnancy rhinitis.

Adult↗

PubMed1999

Drink driving and criminal behaviours as risk factors for receipt of disability pension and sick leave: a prospective study of young men.

AIM: To examine the extent to which drink driving and criminal behaviour would predict receipt of disability pension and high sickness absence rates in young and middle-aged men. DESIGN AND SETTING: A total of 8122 mandatory conscripts, born in 1950 or 1951, from the County of Stockholm were followed in a 22-year longitudinal study. Information was collected at the time of conscription for military service in 1969 and 1970. Data were linked to records on driving while intoxicated (DWI) and other criminal offences between 1970 and 1991 and to information from the Social Insurance Board. FINDINGS: A total of 211 (2.6%) conscripts were granted a disability pension during the follow-up period between 1970 and 1991, and another 373 (4.6%) conscripts had high sickness absence (at least 180 sick days between 1989 and 1991). A total of 642 men had one or more DWI offences from the time of conscription until 1992. The median number of sick-days/sick-listed between 1989 and 1991 was 35.0 for men who were problem drinkers at conscription, 60.3 for drink drivers, 31.0 for men with less serious and 53.0 for men with serious crimes, compared to 21.0 days for the group as whole. In bivariate regression analysis, drink driving implied a relative risk (RR) of a disability pension/high sickness absence of 3.4 (95% CI: 2.8-4.1), and criminality a RR of 3.6 (95% CI: 3.1-4.1). In multivariate logistic regression analysis, controlling for psychosocial factors from conscription and for criminality, drink driving remained a strong predictor (RR 2.1, 95% CI: 1.7-2.7). CONCLUSIONS: Problem drinking, drink driving and criminality are important risk factors for receipt of disability pension and high levels of sickness absence in young men. The findings suggest that preventive efforts undertaken at the time of conscription and during later military service may pay dividends in term of preventing problems later in life.

Adolescent↗

PubMed1999

Nasal congestion during pregnancy.

We define pregnancy rhinitis as nasal congestion in the last 6 or more weeks of pregnancy without other signs of respiratory tract infection and with no known allergic cause, disappearing completely within 2 weeks after delivery. In order to describe physiological variations of nasal obstruction during pregnancy, subjective scores and nasal as well as oral peak expiratory flow values were recorded daily in 23 pregnancies until 1 month after delivery. Scores were higher during early and late pregnancy than in the month after delivery. Objectively registered blockage increased during pregnancy in eight women only. Unexpectedly nine women showed declining blockage. Five of 23 women had pregnancy rhinitis.

Adult↗

PubMed1999

NMR studies on the 46-kDa dimeric protein, 3,4-dihydroxy-2-butanone 4-phosphate synthase, using 2H, 13C, and 15N-labelling.

3,4-Dihydroxy-2-butanone 4-phosphate synthase catalyses the release of C-4 from the substrate, ribulose phosphate, via a complex series of rearrangement reactions. The cognate ribB gene of Escherichia coli was hyperexpressed in a recombinant E. coli strain. The protein was shown to be a 46-kDa homodimer by hydrodynamic analysis. A variety of protein samples labelled with different grades of 13C, 15N and 2H, i.e. one with 100% 2H and 15N, one with 75% 2H, 99% 13C, 15N, and one with 100% 2H, 99% 13C,15N were prepared. Despite the large molecular size, 2- and 3-dimensional NMR spectra of reasonable quality were obtained. Attempts at the assignment of individual 13C, 15N and 1H signals show, in principle, the feasibility of structure determination. The number of NMR signals shows unequivocally that the homodimeric protein obeys strict C2 symmetry.

Base Sequence↗

PubMed1999

A phenomenological study of fibromyalgia. Patient perspectives.

OBJECTIVE: To describe the way in which the fibromyalgia patients understand the meaning of their illness. DESIGN: Qualitative, empirical phenomenological psychological method. SETTING: A collaborative transdisciplinary interview study of patients' described experiences of living with fibromyalgia. No therapeutic relationships existed between patients and researchers. SUBJECTS: Eighteen patients with fibromyalgia were interviewed. Ten of the 18 taped interviews were transcribed and analysed. MAIN OUTCOME MEASURES: Patients' narratives, described experiences of living with fibromyalgia. RESULTS: The patients were intensively involved in efforts to get their self-images as ill persons confirmed. Their experience was that the disease started dramatically, with a variety of capriciously appearing symptoms of unknown cause that gave rise to the suffering. The fibromyalgia patients seemed to develop strategies to cope with a precarious self-image and find ways to manage the thought of what the future would bring. CONCLUSION: The meaning structures revealed in the patients' ways of describing their experiences of living with fibromyalgia seemed to be partially constituted by their efforts to stand forth as afflicted with a disease, which could be a way to help them to manage the demands that they placed upon themselves.

Adaptation, Psychological↗

PubMed1999

Cryo-TEM Snapshots of Ferritin Adsorbed on Small Zeolite Crystals.

The adsorption of macromolecules on zeolite crystal surfaces has been investigated by cryo transmission electron microscopy (TEM) of frozen hydrates. It was determined that ferritin shows different adsorption behavior on NaY (TEM image on the right) and USY zeolites (TEM image on the left).

Journal Article↗

PubMed1998

Serum level of placental growth hormone is raised in pregnancy rhinitis.

OBJECTIVE: To describe any relationship between pregnancy rhinitis and weight gain or serum levels of estradiol, progesterone, placental growth hormone, or insulinlike growth factor I. PATIENTS: Twenty-seven nonsmoking healthy pregnant women aged 22 to 38 years (mean age, 28 years) who had no history of respiratory allergy or chronic nasal or sinus problems volunteered to enter the study. They had no nasal complaints at entry. METHODS: Nasal patency was registered daily from early pregnancy until 1 month after delivery. Nasal and oral peak expiratory flow rates were established, and the subjective blockage was scored from 0 to 4, with 0 indicating no blockage. Serum samples were collected and weight was measured on 4 occasions during pregnancy and again at the end of the study. Pregnancy rhinitis was diagnosed if the subjective nasal obstruction score was 1 or higher every morning for at least 6 weeks immediately preceding delivery, then returned to 0 within 2 weeks and remained at 0 until the end of the study. If on any day other signs of respiratory tract infection occurred, that day was excluded. RESULTS: Pregnancy rhinitis was diagnosed in 5 women. These 5 women showed significantly higher levels of placental growth hormone than the women without the diagnosis. No significant difference was found between the 2 groups regarding body weight or any of the other serum levels studied. CONCLUSIONS: Serum level of placental growth hormone is raised in pregnancy rhinitis and may be involved in its pathogeny. Pregnancy rhinitis does not significantly raise weight gain or serum levels of estradiol, progesterone, or insulinlike growth factor I.

Adult↗

PubMed1998

Increased serum levels of immunoglobulins, C-reactive protein, type 1 and type 2 cytokines in patients with mixed connective tissue disease.

It is controversial whether mixed connective tissue disease (MCTD) should be regarded as a distinct disease entity. In the present study, we investigated immunological parameters in patients with MCTD by studying serum levels of immunoglobulins, C-reactive protein (CRP) and cytokines and compared the results to the corresponding values in systemic lupus erythematosus (SLE), in rheumatoid arthritis (RA) patients and in healthy controls. Using the ELISA technique, serum levels of the cytokines interferon-gamma (IFN-gamma), interleukin-10 (IL-10) and tumour necrosis factor-alpha (TNF-alpha) were investigated. Cytokine levels in SLE and MCTD were correlated to disease activity as assessed by systemic lupus activity measure (SLAM). They were also correlated to serum levels of CRP, IgG, IgA and IgM in the three patient groups. The MCTD patients had the highest levels of immunoglobulins, followed by the SLE patients. In contrast, the highest CRP levels were observed in RA patients, followed by the MCTD patients. The MCTD patients had the highest serum levels of IL-10, but also had elevated IFN-gamma and TNF-alpha levels similar to the RA patients. There was no correlation between the investigated cytokine levels and disease activity, as assessed by SLAM. We conclude that MCTD patients have high immunoglobulin levels as well as high CRP levels and that this situation is compatible with the observed increase in both type 1 and type 2 cytokine levels. The findings imply that MCTD shares some distinct immunological properties with both RA and SLE and that MCTD may also be considered as a separate disease entity according to these properties.

Adult↗

PubMed1998

Preparation and characterization of the recombinant selenomethionine analogue of insulin-like growth factor-I.

Insulin-like growth factor-I (IGF-I), a single-chain polypeptide consisting of 70 amino acids and 3 disulfide bridges, is a member of a class of growth factors that are involved in many proliferative and metabolic processes. To assist in solving the crystallographic three-dimensional structure, we have expressed a recombinant fusion protein precursor of IGF-I in a methionine auxotrophic strain of Escherichia coli grown in the presence of selenomethionine. An homogeneous preparation of selenomethionyl-IGF-I was then obtained by chemical cleavage of the fusion protein. The selenomethionine analogue of IGF-I was characterized by electrospray mass spectrometry, peptide mapping, analytical chromatography, and electrophoresis as well as by biological assays. The final preparation of IGF-I was found to incorporate about 90% of selenium and fully retained the functional activity.

Chromatography, High Pressure Liquid↗

PubMed1998

Nasal symptoms and indices of nasal inflammation in flour-dust-exposed bakers.

OBJECTIVE: To analyze whether indices of nasal airway inflammation in bakers were related to nasal symptoms and exposure to airborne flour dust. METHODS: A cross-sectional study was performed in 12 currently flour-exposed bakers. They were examined by nasal lavage (NAL), visual inspection, a test of mucociliary clearance, and nasal peak expiratory flow (nasal PEF). NAL fluid was analyzed according to the inflammatory markers eosinophil cationic protein (ECP), indicating eosinophilic activity; myeloperoxidase (MPO), indicating active neutrophils; hyaluronic acid (HA) from active fibroblasts; tryptase, indicating activation of mast cells; and albumin, indicating plasma exudation. The bakers were also questioned about respiratory symptoms and working history. Their current and cumulative exposure to inhalable flour dust was estimated after exposure measurements and information about earlier work tasks. Office workers (n=16) without occupational exposure to dust or any other known nasal irritant or sensitizer served as controls. RESULTS: Personal inhalable dust measurements among the bakers working as dough makers or bread formers ranged from 1.0 to 3.8 mg/m3. Of the 12 bakers, 10 reported at least 1 nasal symptom (crusts, blockage, or a runny nose), a proportion significantly greater than that of the controls (P=0.009). Bakers with nasal symptoms had higher concentrations of markers of inflammation in their NALs as compared with nonsymptomatic bakers. The difference was significant for MPO (P=0.02) and HA (P=0.04) in relation to a runny nose. Tryptase was detected in only one NAL of the bakers. There was a positive correlation between the cumulative dose of inhalable flour dust and concentrations of MPO and HA in NAL. Two bakers were sensitized to wheat; they had the highest NAL concentrations of inflammatory markers. CONCLUSIONS: Our results indicate that flour dust exposure in bakers at levels below the current occupational exposure limit causes nasal mucosal inflammation, which, in turn, is related to nasal symptoms. We propose that the inflammation may be nonallergic, characterized by activation of neutrophils and fibroblasts.

Adult↗

PubMed1998

New sterically stabilized vesicles based on nonionic surfactant, cholesterol, and poly(ethylene glycol)-cholesterol conjugates.

Monomethoxypoly(ethylene glycol) cholesteryl carbonates (M-PEG-Chol) with polymer chain molecular weights of 1000 (M-PEG1000-Chol) and 2000 (M-PEG2000-Chol) have been newly synthesized and characterized. Their aggregation behavior in mixture with diglycerol hexadecyl ether (C16G2) and cholesterol has been examined by cryotransmission electron microscopy, high-performance gel exclusion chromatography, and quasielastic light scattering. Nonaggregated, stable, unilamellar vesicles were obtained at low polymer levels with optimal shape and size homogeneity at cholesteryl conjugate/ lipids ratios of 10 mol% M-PEG1000-Chol or 5 mol% M-PEG2000-Chol, corresponding to the theoretically predicted brush conformational state of the PEG chains. At 20 mol% M-PEG1000-Chol or 10 mol% M-PEG2000-Chol, the saturation threshold of the C16G2/cholesterol membrane in polymer is exceeded, and open disk-shaped aggregates are seen in coexistence with closed vesicles. Higher levels up to 30 mol% lead to the complete solubilization of the vesicles into disk-like structures of decreasing size with increasing PEG content. This study underlines the bivalent role of M-PEG-Chol derivatives: while behaving as solubilizing surfactants, they provide an efficient steric barrier, preventing the vesicles from aggregation and fusion over a period of at least 2 weeks.

Cholesterol↗

PubMed1998

Mass spectrometry of peptides in neuroscience.

This review focuses on the contributions of modern mass spectrometry to neuropeptide research. An introduction to newer mass spectrometric techniques is provided. Also, the use of mass spectrometry in combination with high-resolution separation techniques for neuropeptide identification in biological samples is illustrated. The amino acid sequence information that is important for the identification and analysis of known, novel, or chemically modified neuropeptides may be obtained using mass spectrometric techniques. Because mass spectrometry techniques can be used to reflect the dynamic properties associated with neuropeptide processing in biological systems, they may be used in the future to monitor peptide profiles within organisms in response to environmental challenges such as disease and stress.

Mass Spectrometry↗

PubMed1998

Cost-effectiveness analysis and capital costs.

Traditionally, economic evaluations in terms of cost-effectiveness analysis are based, explicitly or implicitly, on the assumption of constant returns to scale. This assumption has been criticized in the literature and the role of cost-effectiveness as a tool for decision making has been questioned. In this paper we analyze the case of increasing returns to scale due to fixed capital costs. Cost-effectiveness analysis is regarded as a tool for estimating a cost function. To this cost function two types of decision rules can be applied, the budget approach and the constant price approach. It is shown that in the presence of fixed capital costs the application of these two decision rules to a specific patient group will give different results. The budget approach may lead to suboptimizations, while using the price as a decision rule will give optimal solutions. With fixed capital costs and when an investment can be used for treating several patient groups, these groups are no longer independent. Therefore the cost-effectiveness analysis has to be performed simultaneously for all patient groups that are potential users of the investment.

Budgets↗

PubMed1998

Cancer treatment in Sweden--costs of drugs, inpatient and outpatient care from 1985 to 1996 and cost effectiveness of new drugs.

This study was carried out to investigate the direct costs for treatment of patients with cancer from 1985 to 1996 in Sweden, and to examine health economic effects of changes in treatment pattern. Material for the study was collected from official statistics and from published health economic evaluations of cancer treatment. Costs for inpatient care decreased during the period, while costs for outpatient care and drugs increased. In total, the direct health care costs for cancer treatment decreased from 1985 to 1996. New drugs registered on the market are often more expensive than the drugs they replace. From a health economic perspective it is not clear, however, that higher drug costs necessarily increase total costs. Further health economic research is needed because many treatment alternatives have not yet been evaluated, and furthermore, because a treatment option can be cost effective in one specific indication but not in another.

Ambulatory Care↗

PubMed1998

Methods of evaluating dental care costs in the Swedish public dental health care sector.

Twenty-six Swedish dental health care clinics participating in the intervention study "Evaluation of caries preventive measures" have been analysed with focus on costs, with the aim of demonstrating techniques suitable for evaluating direct dental care costs and also finding out whether charges are acceptable as a proxy for real costs. Three different approaches to calculating unit costs are discussed: average treatment time cost and two methods of different allocation of overhead cost. Average treatment time cost shows treatment time cost regardless of who (dentist, dental hygienist or nurse) provides the dental care. The other two methods reflect both the differences of treatment costs depending on practitioners' skill level and competence (salary) and the methods of handling overhead cost allocation. Our conclusions are that the proposed methods seem useful for evaluating costs in cost-effectiveness and cost-benefit analysis. The alternative to average treatment time cost or unit time cost depends on what data is available and the perspective of the analysis. This study also concludes that charges are not sufficient as an alternative to a more detailed cost evaluation, at least not in Swedish public dental health care, since charges do not cover costs.

Clinical Competence↗