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Biomedical subjects

P Olsson

Publications and source records attributed to P Olsson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Carbohydrate intake and multiple sprint sports: with special reference to football (soccer).

Six male football players competed in a 90 min game (4-a-side) on two occasions following an exercise and diet (either high- approximately 65% or low- approximately 30% carbohydrate intake) regimen designed to manipulate muscle glycogen concentrations. Movement and technical parameters of performance and selected physiological responses were measured. Pre-game muscle glycogen concentrations following the high carbohydrate diet (mean +/- SD) (395.6 +/- 78.3 mmol x kg(-1) dw) were significantly higher than following the low carbohydrate diet (287.1 +/- 85.4 mmol x kg(-1) dw). The results of the movement analysis showed that the players performed significantly more (approximately 33%) high intensity exercise in the game played following the high carbohydrate diet. No significant differences were found, between the two dietary conditions, in any of the measured technical variables. Plasma FFA and glycerol concentrations in the game played following the low carbohydrate diet were significantly higher after 45 min (905 +/- 103 and 293 +/- 23 micromol x l(-1)) and post exercise (1388 +/- 122 and 366 +/- 36 micromol x l(-1)) compared to the game played following the high carbohydrate diet (532 +/- 137 and 202 +/- 55 micromol x l(-1) and 888 +/- 192 and 266 +/- 27 micromol x l(-1), respectively). Post-exercise blood glucose levels were significantly lower in the game played following the low carbohydrate diet (5.8 +/- 0.3 vs 7.2 +/- 0.3 mmol x l(-1)). No significant differences were found in the mean blood lactate values (3.5 +/- 0.6 and 3.9 +/- 0.5 mmol x l(-1)) or mean heart rates (162 vs. 163.5 beats x min(-1)) between the high and low carbohydrate conditions, respectively. The main finding from this study was that the carbohydrate content of the diet influenced the amount of high intensity exercise performed during a small-sided football game. This suggests that to optimise performances, in not only football but possibly also other multiple sprint sports of similar duration, a high carbohydrate diet should be administered in preparation for intense training and competition.

Adult↗
PubMed1999

Ferrous sulphate gel dosimetry and MRI for proton beam dose measurements.

Ferrous sulphate gel dosimetry has the potential for measurement of absorbed dose distributions in proton therapy. The chemical properties of the gel are altered according to the radiation dose and these changes can be evaluated in three dimensions using MRI. The purpose of this work was to investigate the properties of a ferrous gel used with clinical proton beams. The gel was irradiated with both monoenergetic and range-modulated proton beams. It was then evaluated using MRI. The depth dose by means of the 1/T1 distribution was studied and compared with data from a plane-parallel plate ionization chamber. 1/T1 was shown to be proportional to the dose at a mean proton energy of approximately 90 MeV. The dose response was no different from that obtained using photon beams. However, on normalization at the entrance, the relative 1/T1 at the Bragg peak was 15-20% lower than the corresponding ionization chamber data for the monoenergetic proton beam. Better agreement was found for the modulated beam, but with significant differences close to the distal edge of the 1/T1 distribution. The change in sensitivity with depth was explained by means of a linear energy transfer dependence. This property was further studied using Monte Carlo methods.

Calibration↗
PubMed1999

Women with false positive screening mammograms: how do they cope?

OBJECTIVES: To assess the long term psychological impact on women who were recalled for further investigation after mammography screening and to find any factors that might predict coping ability in order to identify those subjects who require additional support at an earlier stage. SETTING: Counties of Västerbotten and Västernorrland, Sweden. METHODS: A prospective design was used in which 252 recalled women completed questionnaires twice--once within a week of having received the all-clear and again at follow up six months later. A group of 1104 randomly selected, screen negative women were followed up in the same way for comparison. The questionnaire included the Psychological Consequences Questionnaire (PCQ) and basic sociodemographic data. The main outcome measure was the total score on the PCQ at six months. RESULTS: Of the 252 women, 235 (93%) completed both questionnaires. In the control group, 987 (89.4%) women responded. Six months after the all-clear, recalled women were still significantly more anxious (p < 0.001) than those who had been screened but not recalled. The strongest predictor of psychological distress at six months was the PCQ score at the first measurement. Other predictors were a low level of education, living in high density urban areas, and having only one child or no children at all. Widows appeared to cope better than other women. CONCLUSIONS: It is possible to define a group of women with false positive results who are already at risk of coping less effectively at the time of recall. Offering these women counselling or other types of support should be considered.

Adaptation, Psychological↗
PubMed1998

Studies of adsorption, activation, and inhibition of factor XII on immobilized heparin.

The aim of the present investigation was to clarify whether immobilized heparin does, as previously suggested, prevent triggering of the plasma contact activation system. Purified FXII in the absence or presence of antithrombin and/or C1 esterase inhibitor as well as plasma was exposed for 1 to 600 seconds to a surface modified by end-point immobilization of heparin. With purified reagents, a process including surface adsorption and activation of FXII occurred within 1 second. In the presence of antithrombin, the resulting surface-bound alpha-FXIIa was inhibited within that time. Likewise, the adsorption of native FXII from plasma was a rapid process. However, the inhibition of surface-bound alpha-FXIIa was slightly slower than with purified components. Nevertheless, neither beta-FXIIa nor FXIa were found in the plasma phase. Exposure of a surface prepared from heparin molecules, lacking antithrombin binding properties, to plasma resulted in surface-bound alpha-FXIIa within 1 second. In the liquid phase, beta-FXIIa was detected after 2.5 seconds and, 12 seconds later, FXIIa and FXIa in complex with the C1 esterase inhibitor appeared. Addition of heparin to plasma prior to surface exposure did not prevent activation of surface-bound FXII, nor did it increase the beta-FXIIa inhibition rate and prevent FXI activation in plasma, although beta-FXIIa and FXIa-AT complex formation occurred. It is concluded that surface-immobilized heparin, unlike heparin in solution, effectively inhibits the initial contact activation enzymes by an antithrombin-mediated mechanism, thereby suppressing the triggering of the intrinsic plasma coagulation pathway.

Adsorption↗
PubMed1998

Uptake, toxicity and radiation effects of the boron compounds DAAC-1 and DAC-1 in cultured human glioma cells.

PURPOSE: To study the uptake, toxicity and radiation effects in vitro of a diol-amino acid-carborane (DAAC-1) and make comparisons with the previously studied diol-amine-carborane (DAC-1). MATERIALS AND METHODS: Toxicity and radiation effects were studied with clonogenic survival, uptake by measuring the cellular boron content and the subcellular distribution was investigated after organelle separation with centrifugation. The studied cell line was human glioma U343. RESULTS: DAAC-1 showed an accumulation of 1-1.5 times, compared with the culture medium, and was non-toxic up to 47 microg boron/ml. The accumulation of DAC-1 was about 90 times, but toxic effects were detectable already at the concentration 5 microg boron/ml. None of the compounds was localized in the cell nucleus. Following irradiation with thermal neutrons, DAC-1 was about 2.5 times more effective than DAAC-1 and about 4.9 times more effective than neutrons alone, at the survival level 0.2. The dose modifying factors, when compared with the neutron beam alone, were for both DAAC-1 and DAC-1 about 1.5 and about 5 when compared with 60Co-gamma-radiation. CONCLUSIONS: DAAC-1 was less toxic than DAC-1 but gave less accumulation of boron. Both substances gave significant boron-dependent cell inactivation when the test cells were exposed to thermal neutrons.

Boranes↗
PubMed1998

Parenthood as talked about in Swedish ante- and postnatal midwifery consultations. A qualitative study of 58 video-recorded consultations.

In order to explore the manner in which parenthood was discussed in midwifery consultations, 58 video-recorded consultations were analysed. A content analysis revealed a variety of topics concerning conversation on parenthood--topics of an intimate nature and discussions from a societal perspective. Parenthood was not of primary importance in visits, which were mostly directed by the midwives. A phenomenological hermeneutic analysis of the meaning of being a mother revealed a complex and difficult situation of being both needed and dependent. The meaning of being a father revealed a struggle between distancing from and closeness to the child. The mate relationship was indicated as important and under strain. The metaphor of the 'spiders web', where the mother is the spider with the child mostly on her back, the father entering the web on her terms, summarizes the understanding. The results from this study could provide a basis for reflection on the status of the topic of parenthood, on the meaning of being a mother and a father disclosed in the consultations, and ultimately on the organization of ante- and postnatal midwifery care.

Adult↗
PubMed1998

Uptake of a boronated epidermal growth factor-dextran conjugate in CHO xenografts with and without human EGF-receptor expression.

An epidermal growth factor (EGF)-dextran-boron conjugate for targeting against EGF receptor-rich tumours was investigated regarding uptake and distribution in vivo. EGF served as the tumour-seeking part and dextran was the carrier for the potentially toxic boron. Nude mice carrying subcutaneous tumours on the flanks were injected with conjugate either i.v. or intratumorally. The xenografts were from Chinese hamster ovary cells transfected with the gene for the human EGF-receptor (CHO-EGFR), and these cells expressed the EGFR. Non-transfected cells without EGF-receptors (CHO) were used as controls. No accumulations in tumours could be observed following the i.v. injections but there were, in both tumour types, high accumulations in the liver. Following intratumoral injections the accumulations were higher in the CHO-EGFR tumours than in the CHO tumours. The tumour over blood and liver ratios were also higher for the CHO-EGFR tumours than for the CHO tumours. Thyroid accumulations after the intratumoral injections indicate different degradation patterns of the conjugate in CHO-EGFR animals than in CHO animals. In conclusion, after intratumoral injections the conjugate showed receptor-dependent binding to EGFR-rich tumours, and the tumour-to-blood and tumour-to-liver ratios were promising.

Animals↗
PubMed1997

Inhibition of the plasma contact activation system of immobilized heparin: relation to surface density of functional antithrombin binding sites.

End-point immobilization of heparin to artificial materials gives rise to a surface that prevents triggering of the plasma contact activation system and, presumably as a result thereof, generally has thrombo-resistant properties. The present investigation was undertaken to determine what density of immobilized heparin molecules expressing functionally intact antithrombin binding sites is required to achieve these blood compatible properties. Six different heparin surfaces were prepared on polyethylene tubing and studied in contact with human plasma. The content of bound heparin was the same on all surfaces while the densities of antithrombin binding sites ranged from 1 to 28 pmol/cm2. The surfaces expressing 4 pmol/cm2 or more of specific antithrombin binding sites generated no measurable enzymatic activity in contact with plasma, either on the exposed surfaces or in the plasma phases. Below this level, the degree of activation gradually increased with decreasing densities, and in parallel the thrombo-resistant properties deteriorated. Addition of heparin to the plasma phase reduced the capacity of the heparin surfaces to bind antithrombin, leading to a diminished ability of the surfaces to prevent contact activation. This finding supports the hypothesis that antithrombin is the critical coagulation inhibitor for the suppression of contact activation on end-point immobilized heparin.

Anticoagulants↗
PubMed1997

Chemistry and biology of some low molecular weight boron compounds for boron neutron capture therapy.

Boronated DNA targeting agents are especially attractive candidates for BNCT because they may deliver boron-10 to the nuclei of tumor cells. Numerous boron-containing analogs have been synthesized and some have shown promising results in initial biological tests. One of the most challenging tasks in this special field of research remains the finding of suitable targeting strategies for the selective delivery of boron rich DNA-intercalator/alkylator to tumor cells. Synthetic and biological studies of boron compounds suitable for DNA-binding are reviewed. The amino acid p-boronophenylalanine (BPA) is presently of considerable clinical interest. Other boronated amino acids might also be candidates for BNCT either per se, as part of part of tumor-seeking peptides or conjugated to targeting macromolecules. A large number of boronated L- and D-amino acids with varying liphophicility and sterical requirements are now available for evaluation. Recent synthetic and biological studies of aromatic boronoamino acids, carboranylamino acids and carboranyl amines are also reviewed.

Amino Acids↗
PubMed1996

Olsson Replies.

Explore the source record for details and available documents.

Journal Article↗
PubMed1996

Pharmacokinetics and testosterone suppression of a single dose of polyestradiol phosphate (Estradurin) in prostatic cancer patients.

The pharmacokinetics and endocrine effects of polyestradiol phosphate (PEP; Estradurin) were studied by determination of the concentrations of estradiol (E2), unconjugated (E1) and total estrone (tE1; > or = 85% estrone sulfate), and testosterone in serum from 11 prostatic cancer patients after administration of a single intramuscular injection (320 mg). After injection of PEP, serum concentrations of E2, E1, and tE1 increased during 2-3 weeks. Thereafter serum E2 declined monophasically with a mean half-life of 70 days. The elimination of E1 and tE1 seemed to be governed by the formation of E2. The testosterone concentration decreased inversely to the raising E2 level and reached castration levels within 3 weeks and remained at this level for about 2 weeks, whereafter it increased inversely to the decreasing E2 concentrations.

Aged↗
PubMed1996

In vitro determination of toxicity, binding, retention, subcellular distribution and biological efficacy of the boron neutron capture agent DAC-1.

In boron neutron capture therapy (BNCT), 10B is delivered selectively to the tumour cells and the nuclide then forms high-LET radiation (4He2+ and 7Li3+) upon neutron capture. Today much research is focused on development of a variety of boron compounds aimed for BNCT. The compounds must be thoroughly analysed in preclinical tests regarding basic characteristics such as binding and subcellular distribution to enable accurate estimations of dose-modifying factors. DAC-1,2-[2-(3-amino-propyl)-1,2-dicarba-closo-dodecaboran (12)-1-yl-methoxy]- 1,3-propanediol was synthesized at our laboratories and the human colon carcinoma cells LS-174T were used as an in vitro model. The boron compound showed a remarkable intracellular accumulation, 20-100 times higher than the boron content in the culture medium, in cultured cells and was not removed by extensive washes. Approximately half of the boron taken up also remained within the cells for at least 4 days. The DAC-1 compound alone was not toxic at boron concentrations below 2.5 micrograms B/g. The intracellular distribution of the boron compound was investigated by subcellular fractionation experiments and low pH treatments. It is possible that DAC-1 binds to some intracellular molecules or to membranes connected with organelles in the cytoplasm or even to the inside of the outer cell membrane. Another possibility is that the compound, due to the somewhat lipophilic properties, is embedded in the membranes. Thermal neutron irradiations were carried out at the Brookhaven Medical Research Reactor (BMRR). At a survival level of 0.1, DAC-1 + thermal neutrons were about 10.5 times more effective in cell inactivation than the thermal neutrons alone. Monte Carlo calculations gave a mean value of the 10B-dependent specific energy, the dose, of 0.22 Gy. The total physical dose during irradiation of DAC-1-containing cells with a neutron fluence of 0.18 x 10(12) n/cm2 was 0.39 Gy. The dose-modifying factor, at survival level 0.1, when comparing irradiation with thermal neutrons with and without DAC-1 was 3.4, while the dose-modifying factor when comparing neutron irradiations of cells with DAC-1 and irradiation of the cells with 60Co-gamma was 7.3. The results are encouraging and in vivo tests of tissue distributions and tumour uptake should now be carried out.

Biological Availability↗
PubMed1996

Antenatal 'booking' interviews at midwifery clinics in Sweden: a qualitative analysis of five video-recorded interviews.

OBJECTIVE: To describe antenatal 'booking' interviews as regards content and illuminate the meaning of the ways midwives and expectant parents relate to each other. DESIGN: Content analysis and phenomenological hermeneutic analysis of transcribed texts from five video-recorded antenatal booking interviews. SETTING: Midwifery clinics at five health centres in the context of Swedish primary care. PARTICIPANTS: Five midwives, five pregnant women (less than 14 weeks pregnant) and two expectant fathers. FINDINGS: A variety of content themes and ways of relating were found. Combined themes of biomedical and obstetric content occurred as frequently as the sum of social, emotional, antenatal care and life-style themes. The midwives' ways of relating formed two main themes; considering and disregarding the uniqueness of the expectant parents. The midwives directed the interview through their choice of content themes and the way they related to the expectant parents. The expectant parents mainly shadowed the midwives' content themes and ways of relating. The expectant fathers seemed like strange visitors in the women's world. Two perspectives of antenatal midwifery care, obstetric and parental, operated alternately and in competition within the interviews. KEY CONCLUSIONS: The content and the ways of relating within the interviews seem to be connected and could be understood in the light of Buber's writings on dialogue. IMPLICATIONS FOR PRACTICE: The findings provide a basis for reflection on the education of midwives and the planning, training and implementation of midwifery care at antenatal 'booking' interviews.

Adult↗
PubMed1995

Control of contact activation on end-point immobilized heparin: the role of antithrombin and the specific antithrombin-binding sequence.

The uptake and activation of FXII from blood plasma was studied in small-diameter polyethylene tubing, surface-modified by end-point immobilization of heparin. Two preparations of heparin were used to modify the contact-activating properties of the plastic tubing: unfractionated, functionally active heparin and low-affinity heparin, lacking the specific antithrombin-binding sequence and virtually devoid of anticoagulant activity. The uptakes of FXII on the two heparin surfaces were similar. No activated FXII could be demonstrated on the unfractionated heparin surface, whereas on the low-affinity heparin surface nearly all FXII underwent spontaneous activation. The suppression of FXII activation on the unfractionated heparin surface was investigated by using plasma depleted of antithrombin, complement C1 esterase inhibitor, or both. The removal of antithrombin resulted in extensive activation of FXII, whereas the depletion of C1 esterase inhibitor had only a minor effect. Experiments with recalcified plasma showed rapid clot formation during exposure to the low-affinity heparin surface. After depletion of antithrombin, but not complement C1 esterase inhibitor, the recalcified plasma clotted in contact with the unfractionated heparin surface as well. We conclude that antithrombin and the antithrombin-binding sequence in the surface-immobilized heparin are essential for the prevention of surface activation of FXII and triggering of the intrinsic coagulation system.

Animals↗