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Biomedical subjects

U Gustafsson

Publications and source records attributed to U Gustafsson.

42 records · Page 3Linked to original sources
PubMed1990

The relationship between blood flow, development of edema and leukocyte accumulation in post-ischemic rat skeletal muscle.

The relationship between blood flow (xenon washout method), edema formation (percent total water content), and the number of polymorphonuclear leukocytes (PMNLs), as measured by the level of the enzyme myeloperoxidase, has been investigated in post-ischemic skeletal muscle of rats. A tourniquet model of temporary, complete ischemia of one hindlimb for 3 or 4 hours was used. Biopsies were taken after 0.5, 5 and 12 hours of reperfusion (6 experimental groups) and from a control group that had received only anesthesia. After 4 hours, but not 3 hours of ischemia there was a restricted blood flow during the early reperfusion phase, the "no-reflow" phenomenon, indicating severe ischemia. There was no significant accumulation of PMNLs in the skeletal muscle nor was there a correlation between the number of PMNLs in the post-ischemic muscle and the restricted bloodflow. With 4 hours of ischemia and 0.5 hours of reperfusion there was a statistically significant, positive correlation between the number of PMNLs and the amount of edema; no such correlation was evident in either of the other groups. These results suggest that PMNLs are not the major cause of reduced bloodflow or of edema in the early reperfusion phase after total ischemia.

Animals↗
PubMedDate not supplied

Exogenous adenosine induces flowmotion in skeletal muscle microcirculation of the anesthetized rat.

The aim of this study was to investigate the characteristics of the microcirculatory blood flow with laser-Doppler flowmetry (LDF) in skeletal muscle during both regional and systemic infusions of adenosine. A laser-Doppler flowmeter probe was placed on the left gastrocnemius muscle in anesthetized rats. Adenosine was given either systemically in the jugular vein (group A) or administered regionally in the iliac artery (group B). The infusion of adenosine was increased stepwise by 50 micrograms/kg/min, every 10 min, up to 400 micrograms/kg/min. In group A there was a dose-dependent decrease in mean arterial pressure as well as in LDF flow; flowmotion of the LDF signal with a frequency of 1.6 cycles/min was seen at a mean adenosine dose of 240 micrograms/kg/min at a blood pressure of 60 mm Hg. In group B there was a dose-dependent decrease of mean arterial blood pressure but not as marked compared to group A, meanwhile the LDF flow was unchanged; flowmotion was seen at a mean adenosine dose of 220 microgram/kg/min at a blood pressure of 72 mm Hg, with a frequency of 1.5 cycles/min. This study demonstrates that adenosine, given either regionally intraarterially with maintained blood flow, or intravenously with reduced blood flow, induces flowmotion in skeletal muscle microcirculation with a frequency of approximately 1.5 cycles/min.

Adenosine↗
PubMedDate not supplied

Influence of pentobarbital, propofol and ketamine on skeletal muscle capillary perfusion during hemorrhage: a comparative study in the rabbit.

Anesthetics affect tissue blood flow, which is of importance especially in situations of inadequate perfusion, as in hemorrhage. The present study compared the effect of three commonly used anesthetic agents on skeletal muscle capillary and regional blood flow during and after recovery from hemorrhage. Three groups of rabbits were anesthetized randomly with either pentobarbital, propofol or ketamine, chosen such that the anesthetic level, blood pressure and withdrawn blood volume were comparable in all groups. Capillary blood flow was measured using a local hydrogen clearance technique with a multi-wire microelectrode, placed on the left vastus medialis muscle surface, and the contralateral site served for regional microcirculatory blood flow measurements using laser-Doppler flowmetry. Hemorrhage was induced by withdrawal of blood to a mean arterial pressure of 40 mm Hg and monitoring was continued during the subsequent spontaneous recovery period of 120 min. Both capillary and regional blood flow decreased significantly during hemorrhage in all groups. The flow values in the pentobarbital group were given a mean value of 100% and the other two groups were compared with this. Local hydrogen clearance flow decreased from a relative baseline level of 100 to 64% during hemorrhage with pentobarbital, from 87 to 43% with propofol and from 146 to 70% with ketamine. Laser-Doppler flowmetry flow decreased from relative baseline levels of 100, 96 and 139%, to 71, 77 and 103%, respectively, during hemorrhage, whereas the percentage of zero capillary flow values increased from 4 to 34, 19 to 50 and 5 to 27% in the three groups, respectively. The results of the present study indicate that capillary perfusion is best maintained in the ketamine group followed by pentobarbital and propofol last. Furthermore, the flow distribution shapes for each anesthetic indicate a more pronounced deregulation of capillary blood flow in the propofol group than in the others, even at baseline.

Anesthetics↗
PubMedDate not supplied

Serotonin--one possible link between oxygen metabolism and the regulation of blood flow in the brain?

Hyperoxemia is known to alter tissue oxygenation, which in the brain results in a scattered and an uneven distribution of cerebrocortical tissue oxygen pressures (PtO2). This study examined the effect of ritanserin (a highly specific serotonin receptor antagonist, 5-HT2) on the PtO2 distribution during hyperoxemia. The measurements of brain oxygenation were performed on the motor cortex in anesthetized pigs with a multiwire Clark-type microelectrode. Ritanserin was administered (0.035 mg/kg i.v.) during hyperoxemia (inspired oxygen fraction = 0.70). In 4 of 5 animals, the disturbed oxygenation that was registered during hyperoxemia was normalized after the ritanserin injection. These results indicate that serotonin may be involved in the regulation of brain oxygenation during hyperoxemia, and they also suggest that serotonin may be a link in the coupling between the oxygen metabolism and the regulation of blood flow in the brain.

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