Automated preparation of platelet concentrates from pooled buffy coats using the Gambro OrbiSac system.
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Blood Platelets↗
Biomedical subjects
S Larsson
Publications and source records attributed to S Larsson.
Total energy expenditure in underweight patients with severe chronic obstructive pulmonary disease living at home.
AIM: The aim of the study was to assess total daily energy expenditure (TDE), as measured by doubly labelled water (DLW), and describe its components in home-living underweight patients with severe chronic obstructive pulmonary disease (COPD). METHODS: Basal metabolic rate (BMR) was measured prior to the study. Ten patients received DLW, followed by urine analysis by isotope ratio mass spectrometry from 10 standardised occasions during 15 days. Dietary intake was registered by each patient the first 7 days of the study. The patients were also interviewed about their physical activity pattern. RESULTS: Measured BMR was higher than predicted in five of the 10 patients using equations from WHO. Using disease-specific equations, estimated BMR was higher for male, but not for female COPD patients. The best estimation of BMR resulted from prediction including fat-free mass. TDE varied considerably between 5200 and 11,100 kJ. Physical activity level (PAL) ranged from 1.15 to 1.80. Energy intake varied between 4500 and 9100 kJ. In underweight patients with severe COPD, TDE is highly variable, ranging from 110 to 200 kJ/kg body weight. CONCLUSIONS: This is the first study assessing and describing total energy expenditure in underweight patients with severe COPD living at home. Energy requirement in the patient group cannot solely be calculated from prediction equations. BMR should be measured and physical activity level assessed.
Aged↗
Value of air trapping in detection of small airways disease in smokers.
PURPOSE: To test the hypothesis that diffuse and/or focal air trapping are sensitive indicators of airflow obstruction in smoker's small airways disease, when age, gender and presence of emphysematous lesions were allowed for. MATERIAL AND METHODS: Fifty-eight smokers and 34 never smokers, recruited from a randomized population study of men born in 1933, were investigated by HRCT and by extended pulmonary function tests, including a sensitive test for small airways disease (N2 slope). Diffuse air trapping was evaluated by calculating a quotient of mean lung density at expiration and inspiration. Focal air trapping was scored visually by consensus. RESULTS: Diffuse air trapping did not differ between non-emphysematous smokers and never smokers. Furthermore, diffuse air trapping correlated well to the quotient between the residual volume and total lung capacity (RV/TLC, p = 0.01) and was consequently higher in emphysematous smokers than in never smokers. Focal air trapping was found as frequently in smokers without emphysema as in never smokers. Smokers with emphysema showed significantly less focal air trapping. Neither the N2 slope nor any of the other lung function variables differed between those with and without focal air trapping among non-emphysematous smokers. CONCLUSION: Neither diffuse nor focal air trapping are sensitive indicators of smoker's small airways disease.
Aged↗
Stability of internally fixed femoral neck fractures augmented with resorbable cement. A prospective randomized study using radiostereometry.
BACKGROUND AND AIMS: Internal fixation of displaced femoral neck fractures is associated with a high risk for complications such as non-union or avascular necrosis. A stable fracture fixation can improve prognosis although stability is often counteracted by weak osteoporotic bone. The aim with this study was to evaluate whether augmentation with resorbable calcium-phosphate cement could improve fracture stability during the early period after surgery as shown in biomechanical studies. MATERIAL AND METHODS: 40 ambulatory patients with a displaced femoral neck fracture were randomized to treatment with cannulated screws alone (controls) or screws combined with calcium-phosphate cement for augmentation (augmented). All patients were allowed unrestricted weight bearing after surgery. Fracture movement was measured with radiostereometry (RSA) at 1 and 6 weeks. RESULTS: At 1 week the augmented fractures had moved on average 1.9 +/- 1.0 mm while movement in the controls was 5.5 +/- 3.4 mm (p < 0.0001). The average total movement at 6 weeks was 6.9 +/- 2.9 mm and 10.9 +/- 5.1 mm, respectively (p < 0.005). Varus angulation and distal migration of the femoral head were the most common movements for both groups although augmented fractures had moved significantly less at both 1 and 6 weeks. There were no significant differences in angulation between groups around the longitudinal and transversal axes or in migration along the transverse or sagittal axes. CONCLUSION: Augmentation with calcium-phosphate cement improved the stability of internally fixed femoral neck fractures during the first six weeks after surgery, with improvement being less pronounced at six weeks compared with at one week.
Aged↗
Storage of platelets in additive solutions: a pilot in vitro study of the effects of potassium and magnesium.
BACKGROUND AND OBJECTIVES: Platelet additive solutions (PAS) have been shown to be suitable for extended platelet storage but have required the carryover of substantial (30%) amounts of plasma for success. Improving platelet quality by optimizing the composition of PAS may allow a reduction to be made in the amount of plasma carried over. Reducing the proportion of plasma carried over would facilitate some methods of viral inactivation and make available greater amounts of plasma for other needs. MATERIALS AND METHODS: Platelets from six pools of 25 buffy coat platelet units and five apheresis platelet units were aliquoted for storage in plasma, or converted to PAS units in either a specific additive solution (PAS-III), with 30% or 20% plasma, or a modification of PAS-III containing 5.0 mm potassium and 1.5 mm magnesium (PAS-IIIM), with 30% or 20% plasma. Units were stored at room temperature with agitation for 7 days with in vitro testing for biochemical, haematological and functional parameters. RESULTS: Storage of platelets in PAS-IIIM resulted in a reduced rate of glycolysis and better retention of pH, morphology score and ATP levels. Platelets initially showed less evidence of activation when stored in PAS-IIIM, with reduced P-selectin expression. Storage in PAS-IIIM with 20% (rather than the standard 30%) plasma appeared to result in the retention of in vitro properties, similarly to storage in standard PAS-III with 30% plasma. CONCLUSIONS: Storing platelets in an additive solution containing magnesium and potassium improves the functionality of the platelets, as measured by in vitro testing, and may allow a reduction of the amount of plasma required to be carried over to the final unit.
Adenosine Triphosphate↗
Individual dietary intervention in patients with COPD during multidisciplinary rehabilitation.
UNLABELLED: Dietary intervention studies in COPD patients often are short-term inpatient studies where a certain amount of extra energy is guaranteed. The aim of this study was to evaluate the effect of an 1 year individual multifaceted dietary intervention during multidisciplinary rehabilitation. Eighty-seven patients with severe COPD, not demanding oxygen therapy were included, 24 of them served as controls. A dietary history interview was performed at baseline and at study end. Dietary advice given were based on results from the dietary history and socio-economic status. The intervention group was divided into three parts; NW: normal weight (dietary advice given aiming to weight maintenance), OW: overweight (weight-reducing advice) and UW: underweight (dietary advise based on an energy- and protein-rich diet). RESULTS: UW-group: Eighty-one per cent of the patients gained weight or kept a stable weight. OW-group: Fifty-seven per cent lost more than 2 kg NW-group: Seventy-six per cent kept a stable weight or gained weight. Increased dietary intake from baseline was seen for energy protein, carbohydrates and certain micronutrients (P < 0.05) in the UW group. Six minutes walking distance increased by approximately 20 m in both NW (P < 0.05) and UW patients. To conclude, slight, but uniform, indications of positive effects of dietary intervention during multidisciplinary rehabilitation was seen. Dietary intervention in underweight COPD patients might be a prerequisite for physical training.
Aged↗
Randomized clinical trial of laparoscopic versus open fundoplication: evaluation of psychological well-being and changes in everyday life from a patient perspective.
BACKGROUND: The laparoscopic approach in antireflux surgery might have an impact on the patient's daily activities and well-being. METHODS: Sixty patients were randomized to laparoscopic or open 360 degrees fundoplication. Data were collected by questionnaires and interviews preoperatively, 1 month and 6 months after operation. RESULTS: Five patients in the laparoscopic group were converted to open surgery. Psychological general well-being increased after surgery and reached norm values in both study groups. No significant differences were found between the two types of surgery in the per protocol analysis, while the domain self-control was significantly better after open surgery in the intention-to-treat analysis. There was improvement of diet and sleep in both study groups; after 6 months, disturbed sleep was significantly more uncommon after open surgery. Dysphagia and flatulence were new symptoms that were reported after surgery. Overall perception of the results of the operation did not differ between the groups. CONCLUSIONS: Psychological general well-being, diet and sleep improved after both laparoscopic and open surgery. There were only small differences between the groups, but in some respects the results were better after open surgery.
Adult↗
Treatment of osteoporotic fractures.
Fractures are the most common problem associated with osteoporosis and despite advances in prevention and treatment of osteoporosis the number of fractures continue to increase. Along with the three classic locations hip, spine and wrist, there are several other fractures that commonly are related to osteoporosis. The weak bone makes it difficult to achieve a stable bone-implant construct and general weakness of the patient often prevents reduction of load on the injured extremity during healing. The main treatment goal should be preservation of function even at the expense of restoration of exact anatomy. By development of dynamic load-sharing implants and less invasive techniques the results following fixation of osteoporotic fractures has improved. A new strategy has also been to develop materials that will enhance the strength of the cancellous bone that surrounds the metal implant. By using bioactive cement in conjunction with metal implants improved strength has been shown in internally fixed metaphyseal fractures. Encouraging results have also been reported after cement injection into compressed vertebral fractures, so called vertebroplasty. The specific demands involved in the treatment of osteoporotic fractures calls for specific solutions. Apart from augmentation of the cancellous bone and development of new load-sharing devices, endoprosthetic replacement with specially designed fracture prosthesis has become more frequent.
Bone Density↗
Poor retention after closed reduction and cast immobilization of low-energy tibial shaft spiral fractures.
BACKGROUND AND AIMS: The aim of this retrospective study was to analyze retention in cast after closed reduction of low-energy two-fragment tibial shaft fractures. MATERIAL AND METHODS: The material consisted of 72 closed tibial shaft fractures AO/ ASIF type A treated with closed reduction and plaster cast. Fractures were subgrouped according to the AO/ASIF classification and the initial fracture displacement was measured. Final alignment and the frequency of operative intervention due to early loss of reduction were analyzed. RESULTS: 40% of all fractures lost reduction and were operated on. The largest subgroup was A1.2 fractures, a spiral tibial shaft fracture with a fibular fracture at another level. Out of the 28 fractures in this group 61% were converted from cast to early operative intervention. CONCLUSION: Closed reduction and cast treatment of spiral tibial shaft fractures AO/ ASIF type A1.2 had a high failure rate.
Adolescent↗
Good reduction of paresthesia and pain after excision of excessive callus formation in patients with malunited clavicular fractures.
BACKGROUND AND AIMS: Sequelae following non-surgical treatment of clavicular fractures are not uncommon. The aim with this study was to describe results after excision of excessive callus in patients with late onset of paresthesia/numbness. MATERIAL AND METHODS: Eight patients with hypertrophic callus after a malunited clavicular fracture were operated with removal of excessive callus and scar tissue, without stabilizing ostheosynthesis. The reason for surgery was paresthesia/numbness in the arm and hand. There was a delay between trauma and onset of symptoms on average 10 (6-18) months. Neurophysiology prior to surgery was normal in the patients tested. The mean age at trauma was 29 years and the mean time between trauma and operation was 66 months. A prerequisite for surgery was symptoms without recovery for at least 6 months. RESULTS: At follow-up on average 20 months after surgery the paresthesia/numbness, pain at rest, pain during activity, headache and dizziness were significantly reduced or even gone in all patients. The improvement occurred almost immediately after surgery with no signs of recurrence during follow-up. CONCLUSION: Removal of excessive callus and scar tissue after a malunited clavicular fracture can reduce or fully relieve disabling paresthesia and pain even if surgery is done several years after the fracture. Neurophysiological examination is normal due to lack of permanent neurologic damage and can not be used to confirm the symptoms.
Adult↗
Hydroxyapatite coating improves fixation of pedicle screws. A clinical study.
We investigated the effects of hydroxyapatite (HA) coating on the purchase of pedicle screws. A total of 23 consecutive patients undergoing lumbar fusion was randomly assigned to one of three treatment groups. The first received uncoated stainless-steel screws, the second screws which were partly coated with HA, and the third screws which were fully coated. The insertion torque was recorded. After 11 to 16 months, 21 screws had been extracted. The extraction torque was recorded. Radiographs were taken to assess fusion and to detect loosening of the screws. At removal, the extraction torques exceeded the upper limit of the torque wrench (600 Ncm) for many HA-coated screws. The calculated mean extraction torque was 29 +/- 36 Ncm for the uncoated group, 447 +/- 114 Ncm for the partly-coated group and 574 +/- 52 Ncm for the fully-coated group. There were significant differences between all three groups (p < 0.001). There were more radiolucent zones surrounding the uncoated screws than the HA-coated screws (p < 0.001). HA coating of pedicle screws resulted in improved fixation with reduced risk of loosening of the screws.
Adult↗
Improved bone-screw interface with hydroxyapatite coating: an in vivo study of loaded pedicle screws in sheep.
STUDY DESIGN: An in vivo sheep model with loaded pedicle screws was used, wherein each animal served as its own control. OBJECTIVES: To examine the effects of hydroxyapatite (HA) coating on the bone-to-implant interface in loaded spinal instrumentations. SUMMARY OF BACKGROUND DATA: Spinal instrumentation improves the healing rate in spinal fusion, but screw loosening constitutes a problem. HA coating of other implants has resulted in favorable effects on the bone-to-implant interface. METHODS: Nine sheep were operated on with destabilizing laminectomies at two levels: L2-L3 and L4-L5. Each level was stabilized separately with a four-screw instrumentation. Uncoated screws (stainless steel) or the same type of screws coated with plasma-sprayed HA were used in either the upper or the lower instrumentation in a randomized fashion. The animals were killed at 6 or 12 weeks after surgery. The specimens were embedded in resin, ground to approximately 10 microm, and stained with toluidine blue. Histomorphometric evaluation was carried out in a Leitz Aristoplan (Wetzlar, Germany) light microscope equipped with a Leitz Microvid unit. RESULTS: The average percentage of bone-to-implant contact after 6 weeks was 69 +/- 10 for the HA-coated screws and 18 +/- 11 for the uncoated screws (P < 0.03), and after 12 weeks 64 +/- 31 (HA-coated) and 9 +/- 13 (uncoated, P < 0.02). The average bone volume in the area close to the screw was significantly higher for the HA-coated screws at both 6 and 12 weeks. CONCLUSIONS: HA coating improved the bone-to-implant interface significantly, indicating that HA coating can become useful for improving the purchase of pedicle screws.
Animals↗
Preventing exacerbations of chronic bronchitis and COPD.
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Acetylcysteine↗
Enhanced intersystem crossing in donor/acceptor systems based on zinc/iron or free-base/iron porphyrins.
The deactivation pathways of the singlet excited state of a series of zinc or free-base donor porphyrins covalently linked by a bridge to a paramagnetic iron(III) chloride porphyrin acceptor have been studied. These donor-bridge-acceptor systems all share a similar geometry (25 A donor-acceptor center-to-center distance), but the bridges vary in electronic structure. In previously reported investigations of zinc/iron porphyrin systems, the fluorescence quenching of the donor has predominantly been assigned to electron transfer. However, for the porphyrin systems studied in this paper, we show that the dominant deactivation channels are enhanced intersystem crossing and singlet energy transfer. In both series, the intersystem crossing rate (S1-->T1) of the donor moiety is almost doubled in the presence of a paramagnetic high-spin metal-porphyrin acceptor. The significant spectral overlap of the donor fluorescence and acceptor absorption in both series allows for efficient singlet energy transfer (Forster mechanism). Furthermore, the bridging chromophores mediate energy transfer and the enhancement is inversely dependent upon the energy gap between the donor and bridge excited states. Although Marcus theory predicts thermodynamically favorable electron transfer to occur in the systems investigated, the quenching rate constants were found to be independent of solvent polarity, and no charge-separated state could be detected, indicating very small electronic coupling for electron transfer.
Journal Article↗
Smaller amounts of antiretroviral drugs are needed when combined with an active ribozyme against HIV-1.
We have tested for combined anti-HIV-1 effects of a hammerhead ribozyme and antiretroviral drugs and the possibility of reducing the drug burden of patients on highly active antiretroviral therapy (HAART). The antiretroviral compounds used represent the three groups in HAART: nucleoside analogue reverse-transcriptase inhibitors, nonnucleoside reverse-transcriptase inhibitors, and protease inhibitors. A human T cell line (HUT78), stably expressing a hammerhead ribozyme targeted to nef (hhRz.nef(9016-9029)), was infected with HIV-1(SF2) in the presence of a single drug. The combined effects on HIV-1 replication were measured by p24 antigen determinations over a 2-week period. In the presence of the ribozyme, smaller amounts of antiretroviral drugs were required to reduce the HIV-1 p24 levels equally as much as when only drugs were present. The results support a strategy of combining ribozyme gene therapy with HAART to improve the long-term outcome of anti-HIV-1 therapy.
Alkynes↗
Effect of overexpression of Saccharomyces cerevisiae Pad1p on the resistance to phenylacrylic acids and lignocellulose hydrolysates under aerobic and oxygen-limited conditions.
Lignocellulose hydrolysates, obtained by acid hydrolysis for production of bioethanol, contain, in addition to fermentable sugars, compounds that inhibit the fermenting micro-organism. One approach to alleviate the inhibition problem is to use genetic engineering to introduce increased tolerance. Phenylacrylic acid decarboxylase (Pad1p) catalyses a decarboxylation step, by which aromatic carboxylic acids are converted to the corresponding vinyl derivatives. Pad1p-overexpressing Saccharomyces cerevisiae was cultivated in synthetic medium in the presence of model compounds, ferulic acid [(2 E)-3-(4-hydroxy-3-methoxyphenyl)prop-2-enoic acid] and cinnamic acid [(2 E)-3-phenylprop-2-enoic acid], as well as in a dilute acid hydrolysate of spruce to examine the resistance against fermentation inhibitors. Overexpression of S. cerevisiae phenylacrylic acid decarboxylase (Pad1p) resulted in an improved growth rate and ethanol productivity in the presence of ferulic acid, cinnamic acid, and in a dilute acid hydrolysate of spruce. Vinyl guaiacol (2-methoxy-4-vinylphenol) was identified as a major metabolite of ferulic acid, and dihydroferulic acid [3-(4-hydroxy-3-methoxyphenyl)propanoic acid] was detected under oxygen-limited conditions. Styrene (vinylbenzene) and dihydrocinnamic acid (3-phenylpropanoic acid) were identified as metabolites of cinnamic acid. Transformants overexpressing Pad1p had the ability to convert ferulic and cinnamic acid at a faster rate than a control transformant (PAD(C)) not overexpressing Pad1p. This enabled faster growth for Pad1p-overexpressing transformants under both aerobic and oxygen-limited conditions. Pad1p activity was also studied using non-growing cells. The overexpressing transformants showed approximately tenfold higher activity than PAD(C). The Pad1p overexpressing transformants also showed a 22-25% faster glucose consumption rate, a 40-45% faster mannose consumption rate, and a 24-29% faster ethanol production rate in the dilute acid hydrolysate of spruce.
Acrylates↗
Short-term outcome after laparoscopic and open 360 degrees fundoplication. A prospective randomized trial.
BACKGROUND: Despite the lack of randomized trials supporting the laparoscopic approach, laparoscopic antireflux surgery has gained widespread acceptance during the last decade. The aim of this study was to compare the short-term symptomatic and objective outcome after laparoscopic and open 360 degrees fundoplication in a prospective randomized clinical trial. METHODS: Sixty patients with GERD were randomized to undergo either laparoscopic (LF) or open 360 degrees fundoplication (OF). Endoscopy, esophageal manometry, 24-h pH monitoring, clinical symptom evaluation, and symptom scoring according to a validated questionnaire (the Gastrointestinal Symptom Rating Scale [GSRS]) was performed preoperatively and 6 months after surgery. RESULTS: Five patients randomized to the laparoscopic group were converted to open surgery. Esophageal acid exposure was restored to normal in all patients. Lower esophageal sphincter length and resting pressure were significantly increased after both laparoscopic and open fundoplication (p < 0.001); there were no differences between the groups. No significant differences were seen in symptomatic outcome, although there was a trend toward a higher rate of mild dysphagia (p = 0.051) after laparoscopic surgery. GSRS revealed a decrease in reflux score (p < 0.001) and abdominal pain score (p < 0.001) postoperatively. There were no significant differences in GSRS scores between the two groups. CONCLUSION: Laparoscopic 360 degrees fundoplication is as effective in treating reflux disease as open fundoplication. Six months postoperatively, no significant differences were seen in symptomatic or objective outcome. Long-term evaluation is needed.
Adult↗
Hydroxyapatite coating enhances fixation of loaded pedicle screws: a mechanical in vivo study in sheep.
Loosening of the pedicle screws with subsequent non-union or loss of correction is a frequent problem in spinal instrumentation. In a clinical pilot study, coating of pedicle screws with plasma-sprayed hydroxyapatite (HA) resulted in a significant increase of removal torque. An experimental study was performed to investigate the effects of HA coating on the pull-out resistance. Thirteen sheep were operated on with destabilising laminectomies at two levels, L2-L3 and L4-L5. Two instrumentations with four pedicle screws in each were used for stabilisation. Uncoated screws (stainless steel) or the same type of screws coated with plasma-sprayed HA were used in either the upper or the lower instrumentation in a randomised fashion. Four sheep were examined immediately after the application of the screws, three sheep at 6 weeks and four sheep at 12 weeks. Two sheep were euthanised early due to complications. The pull-out resistance was recorded in two HA-coated and two standard screws in each animal. The maximum pull-out resistance was higher for the HA-coated screws at 0 weeks (P< 0.02) and at 12 weeks (P<0.01) when compared to the uncoated screws, while there was no significant difference between the groups at 6 weeks. We believe that the higher pull-out resistance for HA-coated screws at 0 weeks was mainly caused by differences in surface roughness, while the difference at 12 weeks was due to a favourable bone reaction around the HA-coated screws. At 12 weeks, the average stiffness was significantly higher for the HA-coated screws, while there was no significant differences in stiffness between the two screw types at 0 and 6 weeks. Energy to failure was significantly higher for coated screws when compared to the uncoated screws at all three time points. HA coating improves fixation of loaded pedicle screws, with increased pull-out resistance and reduced risk of loosening.
Animals↗