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Biomedical subjects

J Persson

Publications and source records attributed to J Persson.

At least 19 recordsLinked to original sources
PubMed2000

Laparoscopic Burch colposuspension for stress urinary incontinence: a randomized comparison of one or two sutures on each side of the urethra.

OBJECTIVE: To compare 1-year cure rates after laparoscopic Burch colposuspension using one double-bite or two single-bite sutures on each side of the urethra. METHODS: Consecutive women with primary stress urinary incontinence at one university hospital were included. Preoperative clinical and urodynamic evaluation included cystoscopy, cystouretrometry at rest and stress, and a standardized pad test. Immediately before surgery, the patients were randomized to have one or two polytetrafluoroethylene (GoreTex CV 2; W. L. Gore Inc., Flagstaff, AZ) sutures placed on each side of the urethra. During surgery, access to the space of Retzius was achieved by transperitoneal videolaparoscopic technique. Women were scheduled for postoperative interview and pad test 1 year after surgery. RESULTS: We included 161 women in the study; 78 were randomized to one suture (group A) and 83 to two sutures (group B). Median time for surgery was significantly shorter for group A than for group B (60 compared with 77 minutes; P < .001). We examined 158 women 1 year after surgery, at which time 148 performed a pad test. Objective cure rate was significantly higher in group B than in group A (83% compared with 58%; P = .001). CONCLUSION: Two single-bite sutures resulted in a significantly higher objective short-term cure rate than one double-bite suture on each side of the urethra.

Aged↗
PubMed1999

Purification of protein and recycling of polymers in a new aqueous two-phase system using two thermoseparating polymers.

In this study we present a new aqueous two-phase system where both polymers are thermoseparating. In this system it is possible to recycle both polymers by temperature induced phase separation, which is an improvement of the aqueous two-phase system previously reported where one of the polymers was thermoseparating and the other polymer was dextran or a starch derivative. The polymers used in this work are EO50PO50, a random copolymer of 50% ethylene oxide (EO) and 50% propylene oxide (PO), and a hydrophobically modified random copolymer of EO and PO with aliphatic C14H29-groups coupled to each end of the polymer (HM-EOPO). In water solution both polymers will phase separate above a critical temperature (cloud point for EO50PO50 50 degrees C, HM-EOPO, 14 degrees C) and this will for both polymers lead to formation of an upper water phase and a lower polymer enriched phase. When EO50PO50 and HM-EOPO are mixed in water, the solution will separate in two phases above a certain concentration i.e. an aqueous two-phase system is formed analogous to poly(ethylene glycol) (PEG)/dextran system. The partitioning of three proteins, bovine serum albumin, lysozyme and apolipoprotein A-1, has been studied in the EO50PO50/HM-EOPO system and how the partitioning is affected by salt additions. Protein partitioning is affected by salts in similar way as in traditional PEG/dextran system. Recombinant apolipoprotein A-1 has been purified from a cell free E. coli fermentation solution. Protein concentrations of 20 and 63 mg/ml were used, and the target protein could be concentrated in the HM-EOPO phase with purification factors of 6.6 and 7.3 giving the yields 66 and 45%, respectively. Recycling of both copolymers by thermoseparation was investigated. In protein free systems 73 and 97.5% of the EO50PO50 and HM-EOPO polymer could be recycled respectively. Both polymers were recycled after aqueous two-phase extraction of apolipoprotein A-1 from a cell free E. coli fermentation solution. Apolipoprotein A-1 was extracted to the HM-EOPO phase with contaminating proteins in the EO50PO50 phase. The yield (78%) and purification factor (5.5) of apolipoprotein A-1 was constant during three polymer recyclings. This new phase system based on two thermoseparating polymers is of great interest in large scale extractions where polymer recycling is of increasing importance.

Apolipoprotein A-I↗
PubMed1999

Purification of recombinant and human apolipoprotein A-1 using surfactant micelles in aqueous two-phase systems: recycling of thermoseparating polymer and surfactant with temperature-induced phase separation.

An effective system has been developed for purification of apolipoprotein A-1 from Escherichia coli fermentation solution and human plasma using aqueous two-phase extraction and thermal-phase separation. The system included non-ionic surfactants (Triton or Tween) and as top phase-forming polymer a random copolymer of ethylene oxide (50%) and propylene oxide (50%), Breox PAG 50A 1000, was used. The bottom phase-forming polymer was either hydroxypropyl starch, Reppal PES 100 and PES 200, or hydroxyethyl starch, Solfarex A 85. The top-phase-forming polymer and the surfactants are thermoseparating in water solution, i.e., when heated a water phase and a polymer/surfactant phase are formed. Recombinant apolipoprotein A-1, the Milano variant, was extracted from E. coli fermentation solution in a primary Breox-starch phase system followed by thermal separation of the Breox phase where the target protein was recovered in the water phase. Both in the Breox-starch system and in the water-Breox system Triton X-100 was partitioned to the Breox phase. The addition of non-ionic surfactants to the Breox-starch system had strong effect on the purification and yield of the amphiphilic apolipoprotein A-1. In a system containing 17% Breox PAG 50A 1000, 12% Reppal PES 100 and addition of 1% Triton X-100 the purification factor was 7.2, and the yield 85% after thermal separation of the Breox phase. Recycling of copolymer and surfactant was possible after thermal separation of copolymer phase. Approximately 85% of the copolymer and surfactant could be recycled in each extraction cycle. DNA could be strongly partitioned to the starch phase in the primary-phase system. This resulted in a 1000-fold reduction of E. coli DNA in the apolipoprotein A-1 solution obtained after thermoseparation. In extraction from human plasma containing low concentrations of apolipoprotein A-1, it was possible to reach a purification factor of 420 with 98% yield. By reducing the volume ratio to 0.1 Apo A-1 could be concentrated in a small volume of top phase (concentration factor 10) with a yield of 85% and a purification factor of 110.

Apolipoprotein A-I↗
PubMed1999

Thermoseparating water/polymer system: a novel one-polymer aqueous two-phase system for protein purification.

In this study we show that proteins can be partitioned and separated in a novel aqueous two-phase system composed of only one polymer in water solution. This system represents an attractive alternative to traditional two-phase systems which uses either two polymers (e.g., PEG/dextran) or one polymer in high-salt concentration (e.g., PEG/salt). The polymer in the new system is a linear random copolymer composed of ethylene oxide and propylene oxide groups which has been hydrophobically modified with myristyl groups (C(14)H(29)) at both ends (HM-EOPO). This polymer thermoseparates in water, with a cloud point at 14 degrees C. The HM-EOPO polymer forms an aqueous two-phase system with a top phase composed of almost 100% water and a bottom phase composed of 5-9% HM-EOPO in water when separated at 17-30 degrees C. The copolymer is self-associating and forms micellar-like structures with a CMC at 12 microM (0.01%). The partitioning behavior of three proteins (lysozyme, bovine serum albumin, and apolipoprotein A-1) in water/HM-EOPO two-phase systems has been studied, as well as the effect of various ions, pH, and temperature on protein partitioning. The amphiphilic protein apolipoprotein A-1 was strongly partitioned to the HM-EOPO-rich phase within a broad-temperature range. The partitioning of hydrophobic proteins can be directed with addition of salt. Below the isoelectric point (pI) BSA was partitioned to the HM-EOPO-rich phase and above the pI to the water phase when NaClO(4)was added to the system. Lysozyme was directed to the HM-EOPO phase with NaClO(4), and to the water phase with Na-phosphate. The possibility to direct protein partitioning between water and copolymer phases shows that this system can be used for protein separations. This was tested on purification of apolipoprotein A-1 from human plasma and Escherichia coli extract. Apolipoprotein A-1 could be recovered in the HM-EOPO-rich phase and the majority of contaminating proteins in the water phase. By adding a new water/buffer phase at higher pH and with 100 mM NaClO(4), and raising the temperature for separation, the apolipoprotein A-1 could be back-extracted from the HM-EOPO phase into the new water phase. This novel system has a strong potential for use in biotechnical extractions as it uses only one polymer and can be operated at moderate temperatures and salt concentrations and furthermore, the copolymer can be recovered.

Animals↗
PubMed1999

Ketamine antagonises alfentanil-induced hypoventilation in healthy male volunteers.

BACKGROUND: The effects of ketamine on respiration, alone, or in combination with opioids, have not been completely clarified. Both stimulant and depressant effects have been reported, as well as attenuation of opioid-induced hypoventilation at the expense of increased oxygen consumption. These conflicting results might partly be due to dose-dependent mechanisms. We have, therefore, determined the ventilatory effects of ketamine, in combination with alfentanil, using infusions to different pseudo steady-state concentrations. METHODS: On two separate days, eight healthy male volunteers were given alfentanil as a continuous computer-controlled infusion, aiming at a plasma concentration of 50 ng x mL(-1). After reaching apparent steady-state for alfentanil, racemic ketamine or placebo was administered in a protocol randomised for the two days. On the ketamine days a computer-controlled infusion, aiming for escalating ketamine plasma concentrations of 50, 100 and 200 ng x mL(-1), was added to the alfentanil infusion. On the placebo days saline was added. Using a face-mask with an occlusion valve, respiratory parameters were measured during air-breathing and after 6 repetitive 30-s CO2 challenges. RESULTS: The alfentanil infusion induced hypoventilation by decreasing respiratory rate, while tidal volume and respiratory drive were unaffected. This hypoventilation was antagonised by ketamine in a concentration-dependent manner mainly through an increase in respiratory rate. The CO2 response was not affected by alfentanil or ketamine. CONCLUSION: In the dose range of interest for postoperative, intensive-care and pain-clinic settings, ketamine antagonises the resting hypoventilation induced by alfentanil.

Adult↗
PubMed1999

Parental visiting, communication, and participation in ethical decisions: a comparison of neonatal unit policies in Europe.

AIM: To compare neonatal intensive care unit policies towards parents' visiting, information, and participation in ethical decisions across eight European countries. METHODS: One hundred and twenty three units, selected by random or exhaustive sampling, were recruited, with an overall response rate of 87%. RESULTS: Proportions of units allowing unrestricted parental visiting ranged from 11% in Spain to 100% in Great Britain, Luxembourg and Sweden, and those explicitly involving parents in decisions from 19% in Italy to 89% in Great Britain. Policies concerning information also varied. CONCLUSIONS: These variations cannot be explained by differences in unit characteristics, such as level, size, and availability of resources. As the importance of parental participation in the care of their babies is increasingly being recognised, these findings have implications for neonatal intensive care organisation and policy.

Communication↗
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↗
PubMed1998

Out-patient treatment of acute deep vein thrombosis.

BACKGROUND: To assess whether uncomplicated deep vein thrombosis could be treated in an out-patient setting without increasing the frequency of complications, and to determine the proportion of patients with deep vein thrombosis, traditionally treated as in-patients at the Departments of Medicine, who are eligible for such treatment. METHODS: In a multicentre study, carried out at six hospitals of varying sizes and serving a population of about 600,000, consecutive patients over 18 years of age, with verified deep vein thrombosis, primarily presented as acute cases at the respective Departments of Medicine, were considered for treatment on an out-patient basis during a 1-year period. INTERVENTIONS: Those eligible for out-patient treatment were put on low molecular weight heparin and oral anticoagulants, and scheduled for daily attendance at the out-patient clinic of the respective Dept. of Medicine. Details of any complication were recorded according to a standard check-list. The patients underwent a full checkup at three-month follow-up. MAIN OUTCOME MEASURES: Any bleeding event or pulmonary embolism. Progress of thrombosis. RESULTS: Of 523 patients considered for out-patient treatment, 126 (24%) were excluded according to the defined exclusion criteria, 197 (38%) were treated entirely on an out-patient basis, and another 43 (8%) were initially treated in hospital (median two days) before being transferred to the out-patient setting. Three patients had to be hospitalized for suspected complications, but none of these turned out to be serious. No serious bleeding event or thromboembolic complication was registered. CONCLUSIONS: Uncomplicated acute deep vein thrombosis could be safely treated on an out-patients basis. At least 50% of the patients with this diagnosis, former treated as in-patients at the Depts. of Medicine, are eligible for such treatment.

Acute Disease↗
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↗