Biomedical subjects

U Nilsson

Publications and source records attributed to U Nilsson.

At least 19 recordsLinked to original sources

PubMed2005

Stress reduction and analgesia in patients exposed to calming music postoperatively: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: This randomized controlled trial was designed to evaluate, first, whether intra- or postoperative music therapy could influence stress and immune response during and after general anaesthesia and second, if there was a different response between patients exposed to music intra- or postoperatively. METHOD: Seventy-five patients undergoing open hernia repair as day care surgery were randomly allocated to three groups: intraoperative music, postoperative music and silence (control group). Anaesthesia and postoperative analgesia were standardized and the same surgeon performed all the operations. Stress response was assessed during and after surgery by determining the plasma cortisol and blood glucose levels. Immune function was evaluated by studying immunoglobulin A (IgA) levels. Patients' postoperative pain, anxiety, blood pressure (BP), heart rate (HR) and oxygen saturation were also studied as stress markers. RESULTS: There was a significantly greater decrease in the level of cortisol in the postoperative music group vs. the control group (206 and 72 mmol L(-1) decreases, respectively) after 2 h in the post anaesthesia care unit. The postoperative music group had less anxiety and pain and required less morphine after 1 h compared with the control group. In the postoperative music group the total requirement of morphine was significantly lower than in the control group. The intraoperative music group reported less pain after 1 h in the post anaesthesia care unit. There was no difference in IgA, blood glucose, BP, HR and oxygen saturation between the groups. CONCLUSION: This study suggests that intraoperative music may decrease postoperative pain, and that postoperative music therapy may reduce anxiety, pain and morphine consumption.

Adult↗

PubMed2003

Evaluation of denuder sampling for a mixture of three common gaseous diisocyanates.

A denuder sampler has been evaluated for a mixture of three gaseous diisocyanates, i.e. toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). Sampling was performed at a total concentration of diisocyanates close to the Swedish occupational exposure limit (OEL), which is 10 ppbv (69-92 microg m(-3)), for a 5-min period. The denuder tube was coated with a chemosorptive stationary phase consisting of SE-30 (polydimethylsiloxane) and the derivatising reagent dibutylamine (DBA). It was shown that the denuder has a collection efficiency for HDI and IPDI comparable to that of an impinger method, while sampling of TDI resulted in an 8% lower concentration. Both short-term (15 min) and long-term (8 h) sampling periods were shown to yield reproducible results. For 8-h measurements, a sampling flow rate of 5 mL min(-1) was shown to be suitable for the investigated concentration range, i.e. 10-100 ppbv (69-921 microg m(-3)). A flow rate of 25 mL min(-1) or higher resulted in breakthrough after 8 h due to chromatography of the compounds in the adsorbent. The limit of detection (LOD) for the air sampling method is nearly 500 times lower than the OEL. The denuder tubes can be prepared at least 10 days prior to sampling without degradation of performance. Furthermore, they can be stored up to 6 days in a freezer after sampling without significant loss of analytes.

Journal Article↗

PubMed2003

Analgesia following music and therapeutic suggestions in the PACU in ambulatory surgery; a randomized controlled trial.

BACKGROUND: This study was designed to determine whether music (M), or music in combination with therapeutic suggestions (M/TS) could improve the postoperative recovery in the immediate postoperative in daycare surgery. METHODS: One-hundred and eighty-two unpremedicated patients who underwent varicose vein or open inguinal hernia repair surgery under general anaesthesia were randomly assigned to (a). listening to music (b). music in combination with therapeutic suggestions or (c). blank tape in the immediate postoperative period. The surgical technique, anaesthesia and postoperative analgesia were standardized. Analgesia, the total requirement of morphine, nausea, fatigue, well-being, anxiety, headache, urinary problems, heart rate and oxygen saturation were studied as outcome variables. RESULTS: Pain intensity (VAS) was significantly lower (P = 0.002) in the M (2.1), and the M/TS (1.9) group compared with the control group (2.9) and a higher oxygen saturation in M (99.2%) and M/TS (99.2%) group compared with the control (98.0%), P < 0.001, were found. No differences were noted in the other outcome variables. CONCLUSION: This controlled study has demonstrated that music with or without therapeutic suggestions in the early postoperative period has a beneficial effect on patients' experience of analgesia. Although statistically significant, the improvement in analgesia is modest in this group of patients with low overall pain levels.

Ambulatory Surgical Procedures↗

PubMed2003

A comparison of intra-operative or postoperative exposure to music--a controlled trial of the effects on postoperative pain.

The effect of intra-operative compared to postoperative music on postoperative pain was evaluated in a controlled trial. In all, 151 patients undergoing day case surgery for inguinal hernia repair or varicose vein surgery under general anaesthesia were randomly allocated to three groups: group 1 listened to music intra-operatively, group 2 listened to music postoperatively and group 3, the control group, listened to 'white noise'. The anaesthetic and postoperative analgesic techniques were standardised. Pain was assessed using a numeric rating scale (0-10) and patients requirements for postoperative morphine, paracetamol and ibuprofen was recorded. The effect of music on nausea, fatigue and anxiety was also investigated. The results showed that patients exposed to music intra-operatively or postoperatively reported significantly lower pain intensity at 1 and 2 h postoperatively and patients in the postoperative music group required less morphine at 1 h compared to the control group. No differences were noted in the other variables. This study demonstrates that there is a short-term pain-reducing effect of music therapy however, the beneficial effects do not differ if the patient is exposed to music intra-operatively or postoperatively.

Adult↗

PubMed2001

Synthesis and evaluation of molecularly imprinted polymers for extracting hydrolysis products of organophosphate flame retardants.

A molecularly imprinted polymer (MIP) that selectively retains diphenyl phosphate was prepared using a structural analogue, ditolyl phosphate, as a template. Diphenyl phosphate is a degradation product of the flame retardant additive, triphenyl phosphate. The latter has been shown to be a common airborne contaminant in indoor environments and to be emitted from various goods such as video display units. Triphenyl phosphate induces several documented biological responses, including allergenic effects. Two different polymers, one prepared from methacrylic acid and the other from 2-vinylpyridine (2-Vpy), were investigated for their ability to recognise diphenyl phosphate. The polymers were used in solid-phase extraction cartridges (MISPE) and evaluated by comparing their recovery and breakthrough parameters with those of corresponding non-imprinted polymers (NIPs). The polymer made from the basic monomer showed the most selective recognition to the acidic analyte. Diphenyl phosphate was adsorbed to the basic MIP (2-Vpy-MIP) when methanol was used as mobile phase, and approximately 80% of the analyte was recovered when eluted from this polymer using a mixture of methanol and trifluoroacetic acid. There was a clear difference in the retention strengths of 2-Vpy-MIP and the corresponding 2-Vpy-NIP. The selectivity of the investigated 2-Vpy-MIP polymer towards a structural analogue of diphenyl phosphate, di(2-ethylhexyl) phosphate was also assessed. This compound was less strongly retained using the same experimental conditions. The results indicate that the prepared 2Vpy-MIP strongly recognises diphenyl phosphate due to the imprinting effect. This interaction probably arises mostly from an ionic interaction between the basic monomers and the acidic analyte. An LC-electrospray ionisation multiple MS method, using negative ion detection and ion-pair chromatography, was developed for separation and quantification of the strongly acidic dialkylated phosphate esters. The instrumental limit of detection was below 50 pg for all investigated compounds and the MS method was shown to be linear in the investigated range of 0.05-85 ng.

Chromatography, Liquid↗

PubMed2001

Determination of gaseous toluene diisocyanate by use of solid-phase microextraction with on-fibre derivatisation.

An SPME method was developed for sampling gaseous 2,4-toluene diisocyanate (2,4-TDI) involving derivatisation of the isocyanate by reacting with dibutylamine (DBA). The TDI-DBA derivative thus formed was determined by LC-MS-MS utilising atmospheric pressure chemical ionisation (APCI). As a first step, DBA was loaded onto a poly(dimethylsiloxane)/divinylbenzene (PDMS-DVB) fibre coating by direct vapour-phase extraction of a highly concentrated diethyl ether solution of DBA. The DBA-loaded fibre was then exposed to an artificially generated atmosphere of gaseous 2,4-TDI. The linearity of the method ranged from 52.8 to 3100 microg m(-3) (6.8 to 400 ppbv) with a sampling time of 60 min. The proposed method has been applied to 2,4-TDI determination in an artificially generated dynamic standard atmosphere, yielding an approximate method detection limit (MDL) of 2 microg m(-3) (0.25 ppbv). This concentration is one twentieth of the Occupational Safety and Health Administration (OSHA) 8-hour time-weighted average (TWA) exposure limit. The sampler with the PDMS-DVB-DBA coating was found to be stable and retains the required amount of DBA for at least 10 days, an important feature for sampling systems with potential in-situ applications.

Journal Article↗

PubMed2001

Comparison of denuder and impinger sampling for determination of gaseous toluene diisocyanate (TDI).

An air-sampling method employing denuders coated inside with a chemisorptive stationary phase has been evaluated for analysis of the hazardous gaseous 2,4 and 2,6 isomers of toluene diisocyanate (TDI). The denuder stationary phase consisted of polydimethylsiloxane (SE-30) to which dibutylamine (DBA) was added as a reagent for derivatization of TDI. The accuracy and precision of sampling by means of denuders were shown to differ only slightly from those of the established impinger method. The denuder method was, however, also shown to be suitable for long-term measurements (up to 8 h). The limit of determination (LOD) of the method, including LC-APCI-MS-MS analysis, was found to be 1.9 microg m(-3) and 1.2 microg m(-3) for 2,4- and 2,6-TDI, respectively, for short-term measurements (15 min). Significant lower LOD was obtained for long-term measurements. This is well below the Occupational Safety and Health Administration (OSHA) 8-h TWA (time-weighted average) exposure limit, which is 40 microg m(-3) for the sum of the TDI isomers. The denuder method was also found to be robust and easy to handle. The samplers can be prepared several days before sampling with no loss in performance. The contents of denuders should, on the other hand, be extracted immediately after sampling to prevent degradation of the isocyanate derivatives formed.

Journal Article↗

PubMed2001

Development of a personal isocyanate sampler based on DBA derivatization on solid-phase microextraction fibers.

The design and evaluation of a portable diffusive sampler for isocyanates is described. The sampler employs dibutylamine (DBA) loaded onto 60-microm polydimethylsiloxane-divinylbenzene (PDMS-DVB) solid-phase microextraction (SPME) fibers. The DBA-isocyanate derivative is then desorbed by sonication and analyzed by LC-MS using atmospheric pressure chemical ionization (APCI). The samplers are calibrated (i.e. the uptake rate is calculated) by exposing them to a known concentration of hexamethylene diisocyanate (HDI) in a standard gas-generation chamber. The uptake rate for the proposed method, at room temperature (25 degrees C), is 1.13 pg (min ppb(v))(-1) and the method detection limit is 3.2 microg m(-3), equivalent to less than 10% of the airborne time-weighted average (TWA) exposure limits recommended by both the National Institute for Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH). Practical points that should be considered when using the SPME device as a diffusive sampler are discussed.

Air Pollutants, Occupational↗

PubMed2001

A new technique for the analysis of endogenous mediators released following thermal injury.

Few techniques today enable us to measure the complex processes taking place inside a burn wound in vivo. The present in vivo technique was based on a standardised burn model in rat skin. A partial- or full-thickness burn was induced and resulted in a gelatinous oedema located between the skin and the underlying rectus muscle. The oedema has distinct borders to the surrounding connective tissue and is separated and removed easily for further analysis. Myeloperoxidase (MPO) activity used as indicator of neutrofil infiltration was increased significantly in the burn oedema versus non-burned skin. Leukocyte metabolic activity was high as shown by significantly higher free radical formation (ESR) in the oedema than in surrounding burned and non-burned tissue. Leukocyte viability measured by Trypan blue stain was 70% in the oedema of full-thickness burns. In order to decide whether processes taking place in the oedema communicate freely with systemic circulation, we conducted a number of experiments. Results show in burned animals in vivo that intravenous administration of indomethacin induced a strong inhibition of PGE(2) in the burn oedema as compared with saline but, as expected, had no significant effect on LTB(4) synthesis. In conclusion, the present technique allows us to analyse the processes taking place inside the burn wound in vivo and to evaluate the effects of various agents on these processes.

Albumins↗

PubMed2001

Improved recovery after music and therapeutic suggestions during general anaesthesia: a double-blind randomised controlled trial.

PURPOSE: This study was designed to determine whether music or music in combination with therapeutic suggestions in the intra-operative period under general anaesthesia could improve the recovery of hysterectomy patients. METHODS: In a double-blind randomised clinical investigation, 90 patients who underwent hysterectomy under general anaesthesia were intra-operatively exposed to music, music in combination with therapeutic suggestion or operation room sounds. The anaesthesia was standardised. Postoperative analgesia was provided by a patient-controlled analgesia (PCA). The pain scores were recorded by means of a visual analogue scale. Nausea, emesis, bowel function, fatigue, well-being and duration of hospital stay were studied as outcome variables. RESULTS: On the day of surgery, patients exposed to music in combination with therapeutic suggestions required less rescue analgesic compared with the controls. Patients in the music group experienced more effective analgesia the first day after surgery and could be mobilised earlier after the operation. At discharge from the hospital patients in the music and music combined with therapeutic suggestion group were less fatigued compared to the controls. No differences were noted in nausea, emesis, bowel function, well-being or length of hospital stay between the groups. CONCLUSION: This double-blind study has demonstrated that intra-operative music and music in combination with therapeutic suggestions may have some beneficial effects on postoperative recovery after hysterectomy. Further controlled studies are necessary to confirm our results.

Analgesics, Opioid↗

PubMed2001

Complement deposition in renal allografts with early malfunction.

Among patients with early severe impairment of renal allograft function we have previously identified a group displaying isolated deposition of complement factor C3 in glomeruli. Here we studied the pattern of complement deposition more extensively in allograft biopsies from five patients using an immunofluorescence technique. We found a prominent deposition of C3c, C3d and C4d antigens in the glomerular capillary walls, and a positive reaction to vitronectin (S-protein), but only trace amounts of the complement factor C9 neoepitope. Clq, C4c, C3a, iC3b, factor B, properdin, immunoglobulins IgG, IgA or IgM were not found in glomeruli or in any other cortical structure. These findings indicate that most of the demonstrated glomerular C3 consists of C3b and/or C3c/C3d molecules. By immunoelectron microscopy the C3 antigen was found within the glomerular basement membrane. Our findings indicate that there is a mechanism of complement activation involving the early steps of the classical pathway, despite the lack of demonstrable immunoglobulins in the tissue. In analogy with similar reactions described recently in heart allografts, we suggest that this may be a manifestation of a humoral rejection, possibly mediated by a low titer of circulating antibodies directed against endothelial surface antigens, presumed to be the initial step leading to complement activation.

Adult↗

PubMed2001

Production of free radicals measured by spin trapping during operations for stenosis of the carotid artery.

OBJECTIVES: To analyse production of free radicals during operations for stenosis of the internal carotid artery. SETTING: University hospital, Sweden. SUBJECTS: 10 patients operated on for carotid artery stenosis. INTERVENTIONS: Blood samples were repeatedly drawn from the sigmoid sinus through a catheter in the internal jugular vein on the same side, before, during, and after clamping of the internal carotid artery. OXANOH was added to the blood samples in vitro and the radical production calculated from the amount oxidised to OXANO as electron spin resonance. MAIN OUTCOME MEASURES: The relation between radical production and certain clinical variables investigated by partial least squares regression analysis. RESULTS: There were several significant relations. High systolic blood pressure and advanced age were associated with low, and severe degree of stenosis with increased, free radical production. Certain anaesthetic drugs as well as blood variables also influenced the production of radicals. CONCLUSIONS: The technique used seems to offer the possibility to find and study methods to reduce free radical production during this kind of operation.

Age Factors↗

PubMed2000

Cadmium levels in kidney cortex in Swedish farmers.

The cadmium levels in kidney cortex (K-Cd) did not differ statistically between 10 nonsmoking farmers from the south of Sweden, who had a high intake of locally produced food and who were affected by acid precipitation (as indicated by low pH in the drinking water from their private wells) and 10 farmers less affected (medians: K-Cd, 18 vs. 14 microg/g; water pH, 5.2 vs. 7.8). Neither did 10 farmers selected because of "high" blood cadmium (B-Cd) differ from 10 with "low" [medians: K-Cd, 15 vs. 9 microg/g; B-Cd, 2.6 vs. 1.3 nmol/L (0.29 vs. 0.14 microg/L)]. In all 40 farmers, there was an increase of urinary cadmium levels (U-Cd) with decreasing drinking water pH (r(s) = -0.32, P = 0.045). Further, K-Cd increased with rising B-Cd (r(s) = 0.33, P = 0.037), and both B-Cd (r(s) = 0.73, P = 0.0005), and U-Cd (r(s) = 0.74, P = 0.0005) rose with increasing age. Further, there was an association between U-Cd and B-Cd (r(s) = 0.68, P = 0.0005). We could not demonstrate with certainty any effect of the acid precipitation on the cadmium retention in the farmers, although the association between U-Cd and drinking water pH deserves further study.

Adult↗

PubMed1999

Comparative 1H NMR study of hydroxy protons in galabioside and its S-linked 4-thiodisaccharide analogue in aqueous solution.

The NMR data obtained from hydroxy protons have been used to investigate the presence and absence of intramolecular hydrogen bonding in aqueous solutions of 2-(trimethylsilyl)ethyl galabioside (alpha-D-Galp-(1-->4)-beta-D-Galp-O(CH2)2SiMe3) and the S-linked 4-thiodisaccharide analogue. The data show that there is a weak hydrogen bond interaction between O-6H and O-2'H in galabioside, but not in the thio-analogue. The results are in good agreement with those reported for the substances in a Me2SO-d6 solution. It is also shown that the existence of a hydrogen bond can be quite easily monitored by comparing the NMR data of the hydroxy protons.

Carbohydrate Conformation↗

PubMed1999

Are contact allergens stable in patch test preparations? Investigation of the degradation of d-limonene hydroperoxides in petrolatum.

Several of the products formed after oxidation of d-limonene exhibit strong contact allergenic properties. Some, e.g., the hydroperoxides, are unstable compounds. In this study, we have examined whether the limonene hydroperoxides are chemically stable in white petrolatum used for patch testing. We found that the stability of the hydroperoxides was strongly dependent on whether or not the petrolatum was stabilized with alpha-tocopheryl acetate. In the presence of this antioxidant, the hydroperoxides were degraded to a greater extent. The hydroperoxides were shown to be directly reduced to the corresponding alcohols by this agent. On the other hand, the compounds where shown to be stable in non-stabilized petrolatum throughout clinical patch testing for a period of 6 weeks, provided that the preparations were stored in a refrigerator when not used. Thus, it is recommended that vehicles without alpha-tocopheryl acetate are used when peroxy or hydroperoxy compounds are patch tested or used in sensitization experiments. However, it is important to limit the storage time so that optimal conditions are at hand. A fast method was developed to enable isolation and quantification of the hydroperoxides in white petrolatum. This analytical method may also be applicable to other compositions of patch test preparations.

Allergens↗

PubMed1998

Asp477 is a determinant of the enantioselectivity in yeast transketolase.

The conserved residue Asp477 in yeast transketolase is located in the substrate channel of the enzyme and forms a hydrogen bond with the C2-hydroxyl group of the acceptor substrate. The significance of this interaction for the recognition of the preferred acceptor substrates, D-alpha-hydroxyaldehydes was investigated by site-directed mutagenesis. In the wild-type enzyme the kcat/KM values are by three to four orders of magnitude lower for 2-deoxyaldoses or substrates with L-configuration at the C2-atom. In the Asp477 Ala mutant, the kcat/KM values for D-alpha-hydroxyaldehydes are decreased by a thousandfold, while the kcat/KM values for substrates with L-configuration or 2-deoxyaldoses are similar to wild-type enzyme. These results indicate that Asp477 is involved in determining the enantioselectivity of transketolase.

Models, Molecular↗

PubMed1998

Implications of brain imaging for the management of schizophrenia.

Positron emission tomography (PET) can be used to explore relationships between central neuroreceptor occupancy, psychotropic drug blood levels and clinical effects. Treatment with conventional neuroleptics induces high (70-90%) dopamine (D2)-receptor occupancy. The risk of extrapyramidal side effects increases at D2-receptor occupancies above 80%. Standard doses of clozapine induced a low (20-67%) D2-receptor occupancy, but very high (85-90%) 5-hydroxytryptamine (5-HT2A)-receptor occupancy. The novel antipsychotics risperidone and olanzapine induced high occupancy of both D2 and 5-HT2A receptors at suggested standard doses. The occurrence of extrapyramidal side effects in some patients in the higher dose ranges does not support the view that 5-HT2A-receptor occupancy completely prevents the development of extrapyramidal side effects. These results emphasize the need for further exploration of the low dose ranges of risperidone and olanzapine. A preliminary analysis of an ongoing PET study showed that a schizophrenic patient treated with sertindole at 20 mg/day had a D2-receptor occupancy of below 70%. Further studies are needed to show whether sertindole is the first new antipsychotic that induces low occupancy in the clinical dose range, suggesting a mechanism of action distinct from that of classical neuroleptics and analogous to that of clozapine.

Antipsychotic Agents↗

PubMed1998

Bone mineral assessments in the calcaneus after anterior cruciate ligament injury. An investigation of 92 male patients before and two years after reconstruction or revision surgery.

The aim of this study was to assess the Bone Mineral Areal mass (BMA) in the calcaneus of male patients with unilateral anterior cruciate ligament (ACL) injury before and after reconstruction and to assess whether the BMA ratio or the BMA of the injured and uninjured side correlated with the level of activity, functional performance or the time period between the injury and the reconstruction. Ninety-two male patients with unilateral ACL injury were included in the study. The BMA was analysed immediately prior to surgery: a median of 11 (2-192) months after the injury in 30 patients aged 26 (15-41) years scheduled for primary ACL reconstruction (Group A). Forty-nine patients aged 29 (18-49) years had their BMA analysed a median of 24 (23-29) months after the primary ACL reconstruction (Group B). Thirteen patients aged 27 (21-39) years had their BMA analysed a median of 24 (20-45) months after ACL revision surgery (Group C). The median BMA ratio (injured side/uninjured side) was 96 (88-105)% in Group A, 96 (86-118)% in Group B and 95 (83-111)% in Group C. In all three groups, the median BMA value in the calcaneus was significantly lower on the injured side compared with the uninjured side (P=0.001, P=0.0003, P=0.01 in Groups A, B and C, respectively). The time period between the injury and the reconstruction neither correlated with the BMA ratio nor the BMA of the injured or the uninjured side in Group A. The level of activity as measured by the Tegner activity level and the functional performance as measured by the one-leg-hop quotient did not correlate with the BMA ratio in any of the groups. In the 49 patients with a primary ACL reconstruction (Group B), the post-operative Tegner activity level correlated with the BMA, on both the injured and uninjured side (P=0.0003, P=0.0005, respectively), when the BMA was assessed two years after the index operation. Male patients with unilateral ACL injury had a significantly lower BMA in the calcaneus on the injured side compared with the uninjured side before primary reconstruction, two years after primary reconstruction and two years after revision surgery. The time period between the injury and the index operation did not correlate with the BMA. A high level of activity correlated with the BMA on both the injured and the uninjured side two years after primary reconstruction.

Absorptiometry, Photon↗