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Biomedical subjects

J Persson

Publications and source records attributed to J Persson.

At least 19 recordsLinked to original sources
PubMed1998

Purification of recombinant apolipoprotein A-1Milano expressed in Escherichia coli using aqueous two-phase extraction followed by temperature-induced phase separation.

A method for purification of recombinant apolipoprotein A1 in aqueous two-phase systems has been studied. A mutant of apolipoprotein A-1, the Milano variant, was expressed in E. coli. Phase systems containing ethylene oxide (EO)-propylene oxide (PO) random copolymers have been used. These polymers are thermoseparating and have the ability to separate into one water-rich and one polymer-rich phase when heated above a critical temperature i.e. the cloud point. The filtrate from an E. coli fermentation was added to a primary aqueous two-phase system composed of an EO-PO copolymer and Reppal, which is an inexpensive hydroxypropyl starch. Apolipoprotein A-1 was partitioned to the top EO-PO copolymer phase and contaminating proteins to the bottom starch phase. The phase diagrams for Reppal PES 100-EO50PO50 (Ucon) and Reppal PES 100-EO30PO70 were determined. The effect on partitioning, when changing parameters such as polymer concentration, type of polymer, protein concentration, pH, salt concentration and volume ratio, were studied. Studies on E. coli DNA partitioning showed that DNA could be partitioned strongly to the bottom phase. An optimal system was scaled up from 5 g to 5 kg with similar degrees of purification, i.e. 2.5 and 2.7 and yields of 79% and 82% respectively. Furthermore temperature-induced phase formation was used for separation of apolipoprotein A-1 from the copolymer by raising the temperature above the copolymer cloud point; thus, recovering protein in a 'clean' water phase.

Apolipoprotein A-I↗
PubMed1998

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans.

BACKGROUND: Ketamine in sub-dissociative doses has been shown to have analgesic effects in various pain conditions, including neuropathic and phantom-limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood. METHODS: Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS). RESULTS: Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all the patients at the highest dose (0.45 mg/kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. These 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/kg ketamine doses than for morphine 10 mg. CONCLUSION: We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.

Aged↗
PubMed1998

The use of and need for patient classification systems in Swedish neonatal care.

Patient Classification Systems (PCSs) comprise a large group of instruments which describe the condition of a patient regarding severity of disease, severity of illness, risk factors, intensity of nursing care, costs, and so on. They are advocated as an essential ingredient in outcome assessment, but the application of PCSs extends beyond research activities. The aim of this study was to investigate the use of and need for PCSs in Swedish neonatal care units as well as the need for evaluation and improvement of the systems already in use. A survey of 44 units revealed a low level of experience in the use of these systems. Among the 20 units using PCSs, only a few applied standard systems and 11 units pointed out the need for improving these systems. In addition, a second study, based on participant observation and interviews, indicated some potential applications of PCS in a specific unit, such as standard criteria for referring mothers and newborns, staff allocation, staff education and training, standard criteria for parent information, and prognostic systems for medical decision support. Evaluation and adaptation of the existing systems, which are generally developed outside the country, are necessary before they can become a tool for quality assurance, if a national programme for quality of neonatal care is to be established in Sweden.

Attitude of Health Personnel↗
PubMed1997

Technology assessment using the association between outcome measures and patterns of illness severity.

The inclusion of a patient's illness experience as outcome in the assessment of health care technology has revealed methodological limitations such as the interpretation of multi-attribute scores and lack of knowledge about the association between illness and disease information. In an attempt to overcome these limitations, a cross-sectional study is performed to search for patterns of illness severity and investigate the association between illness measures and between illness patterns and disease factors. A sample of 211 patients with ulcerative colitis is studied using the sickness impact profile (SIP) and the rating form for inflammatory bowel disease patient concerns (RFIPC) as illness measures. SIP and RFIPC scores show low association, suggesting that they provide complementary information about the patient's illness status. Cluster analysis is performed using the two measures of illness separately to identify groups of patients with different degrees of severity of illness (clusters). The cluster description covers illness, disease and social and demographic variables. The RFIPC clusters show a general pattern of ascendant rank scores for the RFIPC items. SIP clusters differ, not only in the level of severity, but also in specific types of disability. The patients in the clusters with the highest degree of disability (reflected by SIP) show a non-linear relationship with patients' concerns (reflected by RFIPC) and disease factors.

Adult↗
PubMed1997

Systemic absorption and block after epidural injection of ropivacaine in healthy volunteers.

BACKGROUND: For local anesthetics, the process of removal from the site of administration influences the duration of anesthesia and the risk for systemic toxicity to develop. The systemic absorption of epidural ropivacaine and the time profile of sensory and motor block were studied in healthy volunteers. METHODS: Nine persons simultaneously received 150 mg ropivacaine hydrochloride (7.5 mg/ml) epidurally and 40 mg deuterium-labeled (2H3)ropivacaine hydrochloride (0.25 mg/ml) intravenously. Peripheral arterial and venous plasma samples were collected, and assessments of sensory and motor block were made. RESULTS: The arterial plasma concentrations increased faster than the venous concentrations, with 50% higher maximum concentrations after both intravenous and epidural administration. The absorption was biphasic. A correlation was seen between the duration of sensory block and the slower absorption half-life; that is, the longer the half-life, the longer the duration. The extent of spread varied among the volunteers, with the median upper block level not exceeding T12. The motor block (Bromage score 1) was of slower onset (median, 0.4 h) and of shorter duration (median, 4.1 h) than the sensory block (onset, 0.2 h; duration, 6.5 h at L2 medians). CONCLUSIONS: As much as 50% differences were seen in the arteriovenous plasma concentrations of ropivacaine during the first hour, which has implications for the interpretation of systemic toxic plasma concentrations. The absorption into the general circulation was biphasic, with a correlation between the sensory block and the slower absorption half-life. A faster onset and a longer duration of sensory compared with motor block was seen.

Absorption↗
PubMed1997

Intraindividual and interindividual variability in the disposition of the local anesthetic ropivacaine in healthy subjects.

To predict the risk of adverse reactions to local anaesthetics used in clinical practice, it is crucial to know whether any nonlinearity exists in their pharmacokinetics. The disposition of ropivacaine, a new local anesthetic agent, was evaluated in healthy subjects on the basis of plasma levels in the concentration range obtained after regional anaesthesia. Three intravenous doses of ropivacaine hydrochloride (20, 40, and 80 mg) were given in a double-blind, randomized, complete crossover design. Analysis of variance was used to assess the importance of intra- versus interindividual variability in the basic pharmacokinetics. The mean plasma clearance (400 ml/min), volume of distribution at steady state (40 l), and terminal half-life (1.7 h) were similar, irrespective of dose. The intersubject variability for these parameters was higher than the intrasubject variability. A slight increase in free fraction (15%) with increasing dose might indicate that the lower limit for saturation of protein binding may be reached at the higher plasma levels. One subject (80 mg) reported numbness of the lower lip 2 min after the end of the infusion, which may be a sign of systemic CNS toxicity. The total and free plasma concentration was extrapolated to 1.7 and 0.08 mg/l, respectively.

Adult↗
PubMed1997

Assistive technology selection: a study of participation of users with rheumatoid arthritis.

A new program based on improved user participation for the selection of assistive devices was implemented and its effectiveness and efficiency assessed. The intervention was compared with traditional routines. The study population comprised persons with rheumatoid arthritis who lived in two communities in Sweden. The selection process yielded increased user participation, user satisfaction, an increased number of prescriptions, and consequently also higher costs. The outcome measures showed more vague improvements. No improvement in functional ability was found regarding pain and difficulty with daily activities in the two study groups, but an increased use of assistive devices was found among women below 64 years in the intervention group (p = 0.001). Women below 64 years in the intervention group rated an improved health-related quality of life regarding both the total score (p = 0.017) and the underlying dimensions of physical function (p = 0.012). Even though the intervention yielded positive results on process-variables as increased user participation and an increased number of prescribed assistive devices, only women below 64 years showed an increased use of assistive devices in daily activities and an improved health related quality of life.

Activities of Daily Living↗
PubMed1997

Mucosal bacterial growth in the upper gastrointestinal tract in alcoholics (heavy drinkers).

BACKGROUND/AIMS: Mucosal adherent bacterial flora in chronic alcoholics was studied and compared to a control group referred for upper endoscopy, mainly for dyspepsia. METHODS: 22 alcoholics, admitted to hospital for detoxification, were examined using upper gastrointestinal endoscopy. Gastric and duodenal biopsies were taken for tissue pathology, quantitative and qualitative anaerobic and aerobic bacteriological culture and for culture of Helicobacter pylori (antral biopsies). 12 nonalcoholics, admitted for upper endoscopy mainly for dyspepsia, were chosen as a control group. Seven of these had used gastric acid inhibitors. RESULTS: Gastrointestinal symptoms were common among alcoholics: 20/22 (90%) had diarrhea, nausea and/or abdominal pain. There were signs of gastritis by endoscopy in 64% of the alcoholics and in 58% of the controls. Tissue pathology, however, showed active chronic antral gastritis in 27% of the alcoholics and in 42% of the controls. H. pylori were isolated in 7/22 of the alcoholics and in 4/12 of the controls, which corresponds to the mean prevalence for these age groups in Sweden. Significantly more bacteria, dominated by gram-positive aerobic cocci, were present in the gastric biopsies of alcoholics than in those of controls (mean of 2.9 x 10(6)/g material versus 4.4 x 10(5), p < 0.05). There were 2.6 times more bacteria in the duodenal biopsies of alcoholics than in those of the controls (p > 0.05, NS). Bacterial overgrowth (defined as >2 x 10(3) organisms/g material) was found in the stomach in 20/22 (90%) alcoholics and in 6/12 (50%) controls (p < 0.01). CONCLUSION: Alcoholics have an increased frequency of bacterial overgrowth in the upper gastrointestinal tract. This may contribute to the common gastrointestinal symptoms.

Adult↗
PubMed1997

Surgical correction of dentofacial anomalies: an evaluation of two patient groups with the aid of a a questionnaire.

The study is based on a questionnaire answered by 273 patients with dentofacial anomalies who underwent surgery between 1988-1992 in Boden and Jönköping. The questions concerned how the patients experienced their circumstances before, during, and after treatment, and the care they received. The purpose of the study was to investigate the patients' experience of the treatment, and, thereby, evaluate the treatment team's care in order to improve it. The patients responded mainly positively about the treatment they received, despite it having been both long and trying. The main problems for patients with dentofacial anomalies are functional and aesthetic. Patients were not particularly bothered by the length of time the treatment took or that the results had not been predicted with certainty prior to the treatment. The treatment resulted in a radical change for the better in both appearance and the functional and occlusal aspects of the masticatory system. The questionnaire worked well as an instrument for use by the treatment teams to survey the results of their efforts from the point of view of their patients.

Adolescent↗
PubMed1996

Progression of atherosclerosis in middle-aged men: effects of multifactorial intervention.

OBJECTIVE: To determine the effect of multifactorial intervention against cardiovascular risk factors on ultrasound-determined progression of atherosclerosis in healthy middle-aged men. DESIGN: One hundred and forty-nine healthy middle-aged men were assigned to an intervention group (IG) or a control group (CG). SUBJECTS: The participants had moderately increased risk-factor scores for cardiovascular disease. They were recruited from a health screening programme at the Preventive Medicine Section, Department of Medicine, Lund University, University Hospital, Malmö. During the study period, 32 of the subjects were lost to follow-up, leaving 59 in the IG and 58 in the CG. INTERVENTION: The IG subjects underwent multifactorial intervention for 2 years, the goal being to help them stop smoking and to reduce their blood lipids and blood pressure. MAIN OUTCOME MEASURES: Intima-media thickness and plaque score in the right carotid artery were ultrasonographically determined initially and after 2 years. Blood lipids and blood pressure were measured at the same time, and in the IG also after 3, 6, 12 and 18 months after entry into the study. RESULTS: At the entry into the study, there were no significant differences in major risk factors or ultrasound variables between IG and CG. Blood lipids and smoking decreased significantly during the 2 years of intervention in the IG, whilst these factors remained unchanged in the CG. Intima-media thickness and plaque scores increased significantly in both groups. CONCLUSIONS: No effects on ultrasound variables could be detected after 2 years of multifactorial intervention. A more aggressive intervention programme, possibly more dependent on pharmacological treatment, may be required to obtain reduced progression or regression of atherosclerosis.

Adult↗
PubMed1996

Assistive technologies in stroke rehabilitation from a user perspective.

The purpose of the study was to provide knowledge, from a user perspective, about the selection process for assistive devices. Thirty-eight persons who had suffered stroke were interviewed about their assistive devices, approximately one year after stroke. It was found that the patients had little influence on the choice of assistive devices and that the maintenance and follow-up routines varied among patients. In some cases follow-up was not done at all. Despite these deficits, the patients used their assistive devices as intended.

Activities of Daily Living↗
PubMed1995

Central nervous system effects of subdissociative doses of (S)-ketamine are related to plasma and brain concentrations measured with positron emission tomography in healthy volunteers.

Plasma concentrations, maximum regional brain concentrations, and specific regional binding in the brain after administration of 0, 0.1, and 0.2 mg/kg doses of (S)-ketamine were measured in a randomized, double-blind, crossover study in five volunteers and were related to induced effects such as analgesia, amnesia, and mood changes. Specific binding in the brain was assessed by simultaneous administration of (S)-[N-methyl-11C]ketamine quantified by positron emission tomography. High radioactivities in the brain corresponded to regional distribution of N-methyl-D-aspartate receptor complexes. A significant and dose-dependent reduction of binding was measured as a result of displacement of (S)-[N-methyl-11C]ketamine. Memory impairment and psychotomimetic effects were related to dose, plasma concentration 4 minutes after administration, and decreased regional binding of (S)-ketamine in the brain and were consistently seen at plasma and maximum regional brain (S)-ketamine concentrations higher than 70 and 500 ng/ml, respectively. The magnitude of specific binding of (S)-ketamine, measured with positron emission tomography, can be related directly to drug effects.

Adult↗
PubMed1995

Organotellurium compounds as efficient retarders of lipid peroxidation in methanol.

Diaryl tellurides were found efficiently to retard azo-initiated lipid peroxidation of linoleic acid in methanol. The most efficient compounds, 31 and 39, contained one and two hydroxyl groups, respectively, in the para positions and methyl groups in all four positions ortho to tellurium. As determined by the values of n.kinh, these materials were as effective retarders of lipid peroxidation as vitamin E. Contrary to the conventional antioxidants examined, diaryl tellurides were found to inhibit peroxidation for long times, seemingly with an autocatalytic mechanism. Diaryl tellurides were found to be partially oxidized during the peroxidation. The reduction of tellurium (IV) compounds to the divalent state during the conditions of the experiment is discussed. The reactivity of some diaryl chalcogenides toward 2,2-diphenyl-1-picrylhydrazyl (DPPH) in methanol was studied. All compounds investigated were less reactive than vitamin E. One of the most active organotellurium compounds, bis(4-aminophenyl) telluride, reacted considerably faster with DPPH than the corresponding selenide or sulfide. It was concluded that mechanisms involving both hydrogen atom transfer and electron transfer were operative in the reaction of organotellurides with DPPH.

Antioxidants↗
PubMed1995

Technology and disability. Assessment needs and potential.

In assessing technologies for disabled people, the aims of habilitative or rehabilitative interventions, the concepts of disability and handicap, and the potential of existing and emerging technologies in various social arenas, as well as the structure of service delivery systems, are of importance. A discussion of these issues in the light of previous work on cost and effectiveness in the field is given.

Persons with Disabilities↗
PubMed1995

Assessment of rehabilitation technologies in stroke. Outcomes and costs.

Initial functional ability (Barthel Index, mean 57) was found to be an important predictor of functional ability 1 year after stroke (mean 80) and for costs during the period. On average the total cost for a stroke patient was about SEK 200,000; the main expense, accommodation, averaged about SEK 140,000, while assistive devices amounted to SEK 2,600. Those who use assistive devices, although having achieved a high functional ability, perceive and rate their life situation (Nottingham Health Profile) considerably more impaired than those without assistive devices.

Aged↗
PubMed1995

The cost of the Swedish handicap service system. Implications for technology assessment.

The total cost of the Swedish handicap system is estimated at US $10.7 billion for 1989. The cost is distributed across different authorities with separate legal and financial responsibility. The concept of technology must be extended to include consideration of both the resources spent and benefits gained in the public sector and the magnitude and distribution of transfer payments from social insurance to fulfill its function in handicap policy decision making.

Costs and Cost Analysis↗