| 1. |
- Blomqvist, S, et al.
(författare)
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Early post-traumatic changes in hemodynamics and pulmonary ventilation in alcohol-pretreated pigs
- 1987
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Ingår i: Journal of Trauma. - 0022-5282. ; 27:1, s. 40-44
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Tidskriftsartikel (refereegranskat)abstract
- Time relations among trauma, pulmonary and systemic circulation, and lung function were studied in pigs. Eleven animals (b.w. 25-30 kg) were investigated under balanced anesthesia. Ventilation was mechanically controlled. Hemodynamics, pulmonary ventilation, and gas exchange were serially recorded. Seven animals were pretreated with 40% ethanol in saline and four with saline only. Ninety minutes after the ingestion of alcohol or saline, the animals were subjected to a standardized soft-tissue trauma. Cardiac output decreased significantly 2 minutes after trauma and remained low in both groups throughout the observation period of 30 minutes. Pulmonary vascular resistance was significantly increased in the alcohol-pretreated group but was virtually unchanged in the control animals. Systemic vascular resistance was similarly reduced in the two groups. Total compliance was somewhat lower in alcohol-pretreated animals and 10 minutes after the trauma arterial oxygen tension was significantly lower in the alcohol group than in control animals. Carbon dioxide elimination was reduced after trauma in both groups. It is concluded that pulmonary vascular response increased and that total pulmonary compliance is somewhat decreased shortly after trauma in the alcohol group while gas exchange is almost unchanged. The results indicate a negative interaction between alcohol and trauma
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| 2. |
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| 3. |
- Ljungberg, Michael, et al.
(författare)
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A Monte Carlo program for the simulation of scintillation camera characteristics
- 1989
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Ingår i: Computer Methods and Programs in Biomedicine. - : Elsevier BV. - 0169-2607. ; 29:4, s. 257-272
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for mathematical modelling for the evaluation of important parameters for photon imaging systems. A Monte Carlo program which simulates medical imaging nuclear detectors has been developed. Different materials can be chosen for the detector, a cover and a phantom. Cylindrical, spherical, rectangular and more complex phantom and source shapes can be simulated. Photoelectric, incoherent, coherent interactions and pair production are simulated. Different detector parameters, e.g. the energy pulse-height distribution and pulse pile-up due to finite decay time of the scintillation light emission, can be calculated. An energy resolution of the system is simulated by convolving the energy imparted with an energy-dependent Gaussian function. An image matrix of the centroid of the events in the detector can be simulated. Simulation of different collimators permits studies of spatial resolution and sensitivity. Comparisons of our results with experimental data and other published results have shown good agreement. The usefulness of the Monte Carlo code for the accurately simulation of important parameters in scintillation camera systems, stationary as well as SPECT (single-photon emission computed tomography) systems, has been demonstrated.
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| 4. |
- Ljungberg, Michael, et al.
(författare)
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Dose planning with SPECT
- 1988
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 41:S2, s. 67-70
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Tidskriftsartikel (refereegranskat)abstract
- In nuclear medicine imaging, single photon emission computed tomography (SPECT) is used with increasing frequency for studies of different organs. A new approach is to use quantitative SPECT for dose planning in radionuclide therapy. Important parameters to estimate dose planning are described here.
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| 5. |
- Pärsson, H, et al.
(författare)
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Experimental evaluation of small diameter synthetic arterial grafts
- 1988
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Ingår i: International Angiology. - 1827-1839. ; 7:1, s. 60-64
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Tidskriftsartikel (refereegranskat)abstract
- Platelets labelled with Indium-111 were used to examine the in vivo thrombogenicity of different vascular grafts. The deposition of platelets in two partly different kinds of umbilical vein grafts, double velour Dacron grafts and double velour Dacron grafts with internal collagen was studied as a function of time. The grafts were inserted end to side in the femoral artery of pigs and then imaged for 120 minutes. Platelet distribution was also studied by in vitro static imaging. No difference was seen between the different umbilical vein grafts. The double velour grafts accumulated more platelets, the platelets mainly located in the midportion of the graft. The collagen-impregnated grafts occluded within 45 minutes
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| 6. |
- Ribbe, Else, et al.
(författare)
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Platelet aggregation on peritoneal tube grafts and double velour grafts in the inferior vena cava of the pig
- 1988
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 75:1, s. 81-85
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Tidskriftsartikel (refereegranskat)abstract
- In 14 pigs the infrarenal vena cava was replaced with a peritoneal tube graft or a collagen-coated double velour graft. With 111In-labelled platelets dynamic in vivo imaging of platelet aggregation over the graft was carried out using a scintillation camera. After removal, the grafts were examined by autoradiography for an evaluation of the platelet aggregation pattern. Measurements of activity in different regions of the grafts were also performed. The results indicated low activity uptakes both in vivo and in vitro. The dynamic study did not show any uniform increase of activity content 1-3 h postoperatively, in any of the groups. During the period 2-3 h postoperatively no increasing activity accumulation was found. Hemashield Microvel grafts had an uptake of 0.19 per cent of the total activity while the corresponding figure for peritoneal tube grafts was 0.17 per cent. The activity distribution on different parts of the grafts indicated lower accumulation on the Hemashield graft surfaces than in the anastomoses, while the accumulation was higher on the graft surface of peritoneal tube grafts. The autoradiographical findings supported this indication. In conclusion, low platelet aggregation was found with both dynamic in vivo imaging and in vitro activity measurements on both peritoneal tube grafts and collagen-coated double velour grafts.
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| 7. |
- Thörne, Johan, et al.
(författare)
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Early posttraumatic pulmonary platelet trapping and its potentiation by oral pretreatment with alcohol
- 1986
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Ingår i: The American Journal of Surgery. - : Elsevier BV. - 1879-1883 .- 0002-9610. ; 151:2, s. 216-220
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Tidskriftsartikel (refereegranskat)abstract
- Soft tissue trauma is associated with platelet aggregation and sequestration in the lungs. This is believed to be an early step in the later development of adult respiratory distress syndrome. In the present experiment using a new method for in vivo dynamic studies of platelet sequestration, we wanted to evaluate the effect of soft tissue trauma on pulmonary platelet trapping in pigs and the influence of acute alcohol intoxication. The results show that significant pulmonary platelet trapping is registered within minutes of trauma and that alcohol significantly increases platelet sequestration in the lungs. This indicates an increased risk for posttraumatic pulmonary problems in alcohol-intoxicated trauma victims
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| 8. |
- Thörne, Johan, et al.
(författare)
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Effect of ticlopidine and prostaglandin E on endotoxin-induced pulmonary platelet sequestration in vivo
- 1986
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Ingår i: Circulatory Shock. - 0092-6213. ; 20:1, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- Prostaglandin E1 has earlier been shown to decrease pulmonary platelet trapping (PPT) following shock. This experiment was performed to evaluate a new method to study PPT in vivo, and to study the effect of prostaglandin E1 and a new antiplatelet drug (ticlopidine) on PPT in rabbits after i.v. administration of endotoxin. Following platelet labeling with In-111, the rabbits were placed under a scintillation camera for continuous measuring of the activity distribution for 40 minutes. The first five minutes represented reference values, whereafter endotoxin E. coli was injected i.v. The following 2-4 minutes showed a sudden increase of radioactivity over the lungs and a simultaneous decrease over the heart, indicating PPT in the nontreated animals, followed by a slow decrease to almost preshock values during the following 30 minutes. Animals receiving prostaglandin E1 showed a significantly lower activity peak in the lungs after the administration of endotoxin, while the corresponding peak in ticlopidine-treated animals did not differ from that seen in the nontreated animals. In all groups, endotoxin caused a decrease in platelet count, but it was significantly lower in the PGE1-treated animals. The results have shown that this diagnostic model for PPT is reliable and may be used for evaluation of the effect on platelet aggregation in vivo of different drugs
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| 9. |
- Widner, Håkan, et al.
(författare)
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Scintigraphic method to quantify the passage from brain parenchyma to the deep cervical lymph nodes in rats
- 1987
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - 1619-7070. ; 13:9, s. 456-461
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Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the kinetics of the passage from the brain parenchyma to the lymphatic system in vivo a high resolution scintillation camera technique was developed. Albumin, albumin colloids and dextran labelled with 99mTc were injected into the right side of the thalamus of anesthetized rats. Continuous measurement of the activity distribution in head and neck were performed for 70 min. Rate constants were calculated by means of a computer program for compartment analysis. The animals were killed 10 h postinjection, to measure the activity in tissue samples. For some animals, images were registered up to 24 h after injection. This work presents an in vivo technique to clarify the particle flow paths in the brain and make quantification possible. The method is simple and does not require continuous blood or lymph sampling. Our work shows that there is a substantial flow of injected material from the brain via lamina cribriformis to the lymphatic system. This route is of great interest for the drainage of the interstitial fluid of the brain. We have also shown a difference in flow for dextran particles with different charge
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