Biomedical subjects

K Gustafsson

Publications and source records attributed to K Gustafsson.

At least 19 recordsLinked to original sources

PubMed2006

Leakage of O2 precursor molecules from inert hydrogen islands on a Pt(111) surface.

We have observed, using infrared spectroscopy, that the precursor-mediated O2 chemisorption on the clean and the partially hydrogen-covered Pt(111) surfaces exhibits opposite temperature dependencies above the temperature for stable O2 physisorption. While the chemisorption probability on the clean surface increases with increasing temperature due to thermal activation of the precursor, it decreases on the partially hydrogen-covered surface which we suggest is due to a general loss of the mobile precursor molecules by thermal desorption from chemically inert hydrogen islands.

Journal Article↗

PubMed2006

Dipole active vibrations and dipole moments of N2 and O2 physisorbed on a metal surface.

We have, in infrared reflection absorption measurements, observed narrow dipole active absorption lines associated with the fundamental internal vibrational transitions of N(2) and O(2) physisorbed at 30 K on the chemically inert Pt(111)(1 x 1)H surface. Such transitions are forbidden for free homonuclear molecules and become dipole active at a metal surface due to polarization induced surface dipole moments. The measurements show that the internal stretch vibration frequencies are lowered by 7-8 cm(-1) relative to the gas phase values. The measured static and dynamic dipole moments are in the ranges of 0.06-0.07 and 0.001-0.002 D, respectively. We find that good estimates of the induced dynamic as well as the static dipole moments can in general be obtained from a van der Waals model but that the ratios of the measured static and dynamic moments indicates a need for a refinement of the dipole moment function.

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PubMed2005

Precision measurement of the weak mixing angle in Møller scattering.

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) +/- 10(syst)] x 10(-9), leading to the determination of the weak mixing angle sin2(thetaW(eff) = 0.2397 +/- 0.0010(stat) +/- 0.0008(syst), evaluated at Q2 = 0.026 GeV2. Combining this result with the measurements of sin2(thetaW(eff) at the Z0 pole, the running of the weak mixing angle is observed with over 6sigma significance. The measurement sets constraints on new physics effects at the TeV scale.

Journal Article↗

PubMed2005

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering.

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Journal Article↗

PubMed2005

Older women and dietary advice: occurrence, comprehension and compliance.

BACKGROUND: When a person becomes ill, traditional food habits may come into conflict with the disease-related recommended diet. AIM: The aim was to study perceptions of receiving dietary advice, the occurrence and comprehension of such advice and compliance among older women diagnosed with Parkinson's disease, stroke or rheumatoid arthritis. METHODS: The study took an ethnographic approach. Fifty-four community-dwelling women, 64-88 years of age, were interviewed using an open-ended interview technique during visits to their homes. FINDINGS: Two themes were found: 'dietary advice - occurrence and comprehension' describes whether the women had received dietary advice and, if so, how they understood the information. In the theme 'compliance with dietary advice', two principal reasons for complying or not complying with advice were found: First, women expressed a 'food interest', such that they were either 'interested in disease-related diet' or held a general view of the significance of foods and complied with the advice for their own 'health interest'. Secondly, the women were 'uninterested in food changes'. This could be because of 'poor appetite', 'food and disease ambivalence', 'habitual and preferred foods'. CONCLUSION: Dietary advice should be based on women's food preferences and habitual foods. It is important to inform about known relations between food and disease, but also to support eating favourite foods, thereby facilitating women's well-being.

Aged↗

PubMed2004

Infrared spectroscopy of oxygen adsorbed on hydrogen covered Pt(111).

Using infrared reflection absorption spectroscopy we have investigated how preadsorbed hydrogen affects the adsorption of O(2) on the Pt(111) surface at temperatures below the onset of the water formation reaction. On the fully hydrogen covered surface, Theta(H)=1, O(2) physisorbs at temperatures below 45 K, the weakly dipole active internal stretch vibration is observed at 1548 cm(-1). Unlike on the clean Pt(111) surface, this adsorption state does not act as a precursor for O(2) chemisorption. The physisorbed molecules simply desorb above 45 K and no chemisorbed O(2) state is populated directly from the gas phase in the temperature range 45-90 K. When the surface is approximately half covered, Theta(H) approximately 0.4, with preadsorbed hydrogen, O(2) chemisorbs on the clean Pt(111) surface regions in the characteristic peroxolike and superoxolike states with vibration frequencies around 700 cm(-1) and 870 cm(-1). These values correspond to dense O(2) islands which develop already at low O(2) coverages. At this hydrogen coverage, we find that the initial sticking probability of chemisorbed O(2) is drastically reduced at 90 K and the general uptake also proceeds slowly when compared with observations for the clean surface. We suggest that this is due to a change in the behavior of the physisorbed O(2) precursor.

Journal Article↗

PubMed2004

Observation of parity nonconservation in møller scattering.

We report a measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in Møller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).

Journal Article↗

PubMed2004

Infrared spectroscopy of physisorbed and chemisorbed O2 on Pt(111).

The adsorption of O2 on the Pt(111) surface, with particular emphasis on the influence of substrate temperature, has been studied by infrared reflection absorption spectroscopy (IRAS). In the temperature range 30-90 K the IRAS spectra reveal three different molecular adsorption states. A physisorbed state appears below 40 K while chemisorbed peroxo- and superoxo-like states are observed in the whole temperature range, the characteristic vibrational frequencies are at full coverages of 16O2, 1543 cm(-1) and around 700 cm(-1) and 870 cm(-1), respectively. Flash heating from 30 K to 45 K reveal that the physisorbed state acts as a precursor to the superoxo chemisorption. Theoretical calculations suggest that peroxo molecules may occupy both fcc and hcp threefold sites on the Pt(111) surface. However, within the high resolution of the IRAS measurements we only observe one peroxo state in the temperature range 45-90 K, assigned to occupy the fcc site. The peroxo adsorption probability is significantly lower at 45 K than at 90 K, presumably due to reduced thermal activation from the physisorbed precursor state. A longer lifetime in this precursor state at the low temperature results in formation of larger superoxo islands already at low oxygen coverage.

Journal Article↗

PubMed2004

Parity-violating electron deuteron scattering and the proton's neutral weak axial vector form factor.

We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2=0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51+/-0.57 (stat)+/-0.58 (syst) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions.

Journal Article↗

PubMed2004

Molecular identity, expression and functional analysis of interleukin-1alpha and its isoforms in rat testis.

Interleukin-1alpha (IL-1alpha) is a proinflammatory cytokine that has also been found to act as a paracrine mediator involved in the regulation of testicular functions. The present review provides an overview of the role of IL-1alpha in testicular physiology. Bioactive IL-1alpha isolated from adult rat testis was found to consist of three distinct immunoreactive protein species with apparent sizes of 45, 24 and 19 kDa. These isoforms showed bioactivity in a thymocyte proliferation and steroidogenesis assays with different biopotencies. The background of the molecular heterogeneity and processing, secretion and regulation of the isoforms of testicular IL-1alpha are discussed. All three isoforms have been found to be secreted into the testis tubular lumen and interstitial space. We have provided evidence that IL-1alpha is a paracrine factor that may be of importance in, e.g., the regulation of Leydig cell steroidogenesis. Pathophysiologically, testicular IL-1alpha may contribute to testicular relapse of acute lymphocytic leukemia in boys.

Animals↗

PubMed2004

Five-day food intake in elderly female outpatients with Parkinson's disease, rheumatoid arthritis or stroke.

AIM: The aim of this study was to describe and analyse the intake of food, energy and selected nutrients in elderly outpatients, i.e. women with Parkinson's disease, rheumatoid arthritis or stroke. SUBJECTS AND METHODS: Sixty-three elderly women aged 64-88 years participated in the study. For assessing dietary intake, a repeated 24-h recall and an estimated food diary for three consecutive days were used. RESULTS: The mean age was 73.4 +/- 6.6 years. Mean reported daily energy intake was 6.4 +/- 1.7 MJ, i.e. lower than reference figures for all groups. However, looking at nutrient density, only intakes of vitamin E and folate were below recommended levels. The most frequently consumed food groups were bread, coffee, milk products, buns and cookies, and spreads. CONCLUSION: The reported energy intake among the elderly female outpatients was low. This might be explained by actual low intake and/or under-reporting. However, the intake of most vitamins and minerals, i.e. nutrient density, was adequate, with the exception of vitamin E and folate intake, which was below recommended levels. Food intake showed large variation and good diet composition, and there was a tendency towards high consumption of food items that are easily prepared and eaten.

Aged↗

PubMed2003

Meals and snacks among elderly self-managing and disabled women.

AIM: The aim of this study was to describe the frequency and distribution of self-managing and disabled elderly women's eating events, as well as to investigate which definition/names the women had given their different eating events and to categorise these into meals and snacks. An additional aim was to study the composition of meals and snacks, and analyse the nutritional significance of these eating events in terms of energy and macronutrients. SUBJECTS: Elderly women, both self-managing (n=139) and disabled (n=63; with Parkinson's disease, rheumatoid arthritis or stroke), aged 64-88 years, and living at home participated. METHODS: A repeated 24 h recall and an estimated food diary for three consecutive days were used. RESULTS: The eating events defined by the women that were categorised as meals contributed 74% of the total daily energy intake, while snacks contributed 22-23%. The meals that the women had defined as dinner, was the most energy dense meal. The frequency of eating events not defined by the women, was 30-34%, but contributed only 3-4% of the total daily energy intake. The disabled women had a significantly lower energy content in meals and most snacks, compared to the self-managing women. CONCLUSION: The main conclusion was that elderly women still living at home had their meals distributed during the day and that these meals were characterised by individuality and flexibility.

Aged↗

PubMed2003

Food and nutrient intake in a group of self-managing elderly Swedish women.

BACKGROUND: With the increasing numbers of elderly women living at home, there is an interest to investigate the dietary intake of this group. OBJECTIVE: To investigate the food and nutrient intake in a group of self-managing elderly women in Sweden. DESIGN: A 3-day self-reported food diary and a repeated 24-h dietary recall were used. The study comprised 135 single-living or married/cohabiting women (mean age 79.5 8.0 years). RESULTS: Mean energy intake for the whole group was 6.8 1.9 MJ, and low energy figures were obtained in all age groups indicating some possible under-reporting with a calculated EIrep/BMRest of 1.24 0.36 for the whole group. Overall, energy and nutrient intake was similar in the different age groups (64-68 yrs, 74-78 yrs and 84-88 yrs). Reported intakes of vitamin D (4.8 2.7 mg), tocopherol (5.9 2.2 mg), iron (8.5 2.9 mg), folate (200 8.7 mg) and selenium (29 11 mg) were low compared to recommended intakes. Only minor differences between women in different household types were found. The women reported a variety of food items in their diet. CONCLUSIONS: Overall, the results from this study indicate that self-managing elderly women report low energy figures, but have a sufficient intake of most nutrients. However, there is a tendency that the oldest women, i.e. 84-88 yrs have lower intakes.

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PubMed2002

Reasons among older Swedish women of not participating in a food survey.

OBJECTIVES: To (a) examine participation rate as a function of municipality, age group and living status; and (b) investigate the main reasons for exclusion and declining as stated by the women themselves. DESIGN: Analysis of participation rate and content analysis of statements given in phone calls explaining exclusion or declination from a project in which 24 h recalls and food-diaries were used. SUBJECTS: Self-managing Swedish women (n=505) were systematically selected from a stratified random sample covering single living and cohabiting women aged 64-68, 74-78 and 84-88 y living in three municipalities. RESULTS: No significant differences were found among included and declining women when municipalities and living status was analysed, but significantly more women in the oldest group were excluded (P>0.01). Among those in their 80s living at home, the usual reasons for exclusion were illness, disability or dementia, and many lived in institutions for old people. The four most used explanations to decline participation were 'lack of time', 'tired, fragile, sick or having bad memory', 'not willing to participate in scientific studies' and 'too old and nothing to contribute'. CONCLUSIONS: The participation rate was, compared with other food surveys in the older generation, fairly good, especially among those in their 80s. However, the most active and the very ill and disabled did not participate. SPONSORSHIP: The Swedish Council for Social Research, the Swedish Council for Forestry and Agricultural Research, the Swedish Foundation for Health and Care Sciences and Allergy Research and Uppsala University.

Age Factors↗

PubMed2001

Measurement of the charged pion electromagnetic form factor.

Separated longitudinal and transverse structure functions for the reaction 1H(e,e(')pi(+))n were measured in the momentum transfer region Q2 = 0.6--1.6 (GeV/c)(2) at a value of the invariant mass W = 1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parametrization fitted to very low Q2 elastic data.

Journal Article↗

PubMed2001

Meals and energy intake among elderly women--an analysis of qualitative and quantitative dietary assessment methods.

OBJECTIVE: The objective of this study was to analyse whether a qualitative method, in relation to traditional dietary assessment methods, was adequate to establish sufficient energy intake and energy content in separate meals in a population of elderly women. METHODS: One hundred and thirty-five elderly women, aged 63-88 years, living at home from three communities in mid-eastern Sweden participated in the present study. The quantitative methods used were a combination of repeated 24-h recall and a 3-day estimated food diary. The qualitative method used was the Food-Based Classification of Eating episodes model (FBCE). RESULTS: The mean intake of energy estimated by the 5-day registration was 6.8 +/- 1.9 MJ. The total number of eating events was 5.22 +/- 1.04 per day. On a group level, FBCE was useful to describe the diet among a group of elderly women; however, on an individual level, some complete meals were low or very low in energy, due to small portion sizes. CONCLUSION: The main conclusion was that a qualitative method, such as FBCE, must be supplemented with a dietary assessment method giving the energy intake to ensure that it is sufficient, especially when studying groups at risk for malnutrition.

Aged↗

PubMed2001

Effects on the nervous system in different groups of workers exposed to aluminium.

OBJECTIVE: To investigate possible neurotoxic effects in groups of aluminium pot room and foundry workers, aluminium welders, and a small group of workers exposed to aluminium in the production of flake powder. METHODS: Exposure to aluminium was evaluated with aluminium concentrations in blood and urine as well as a questionnaire. The groups exposed to aluminium were compared with a group of mild steel welders. Neurotoxic effects were studied with mood and symptom questionnaires and several psychological and neurophysiological tests. RESULTS: The pot room and foundry workers showed very low aluminium uptake as their aluminium concentrations in blood and urine were close to normal, and no effects on the nervous system were detected. The group of workers exposed to flake powder had high concentrations of aluminium in blood and urine, even higher than those of the aluminium welders. However, aluminium could not be shown to affect the functioning of the nervous system in flake powder producers. Although significant effects could not be shown in the present analysis of the data on welders, the performance of the welders exposed to high concentrations of aluminium was affected according to the analyses in the original paper from this group. CONCLUSIONS: For the pot room and foundry workers no effects related to the exposure to aluminium could be found. For the group of flake powder producers exposed for a short term no effects on the nervous systems were evident despite high levels of exposure. Due to the high concentrations of aluminium in the biological samples of this group, measures to reduce the exposure to aluminium are recommended, as effects on the central nervous system might develop after protracted exposures. However, this assumption needs to be verified in further studies.

Adult↗

PubMed2000

Efficient gene delivery to vascular smooth muscle cells using a nontoxic, synthetic peptide vector system targeted to membrane integrins: a first step toward the gene therapy of chronic rejection.

BACKGROUND: Chronic rejection is now the major cause of allograft failure. A prominent characteristic of the histopathology is extensive intimal proliferation of vascular smooth muscle cells. Targeting vascular smooth muscle cells by gene therapy techniques offers a possible avenue for arresting or reversing chronic rejection. Defining suitable non-viral DNA vectors for this application is the objective of this study. METHODS: A 31 amino acid synthetic peptide has been evaluated as a DNA vector for primary cultures of vascular smooth muscle cells of man, rabbit, and rat. The vector comprises a 15 amino acid integrin-binding domain and a chain of 16 lysines for electrostatic binding of DNA. Three agents known to promote exit of vector/DNA complexes from endocytic vesicles were studied systematically to define optimal, non-toxic conditions for gene delivery. RESULTS: Initial binding studies on frozen sections showed that the integrin-binding domain binds strongly to vascular smooth muscle cells in all three species, thereby establishing vascular smooth muscle cells as a potential target for this receptor-targeted DNA vector system. Primary cultures of vascular smooth muscle were therefore studied. The use of chloroquine to assist endocytic exit, which works well on immortalized cell lines, was of little value because of toxicity to the primary vascular smooth muscle cells. The addition of cationic lipids to polylysine-molossin/DNA conjugates gave excellent reporter gene expression, but required mildly toxic doses of cationic lipid, and resulted in some loss of integrin specificity of the vector system. The optimal system involved the use of the amino terminal 20 amino acids of the hemagglutinin of the influenza virus. This peptide, when added to polylysine-molossin/DNA complexes at an optimal w/w ratio of 5:1:2 (polylysine-molossin/DNA/fusogenic peptide) resulted in 25-30% transfection of vascular smooth muscle cells with good levels of gene expression and no toxicity. CONCLUSION: This represents an effective and safe DNA vector, comprised entirely of small synthetic peptides, and therefore readily standardized for clinical and experimental application.

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