| 1. |
- Sjöberg, Trygve, et al.
(författare)
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Antagonism of thromboxane receptor induced contractions in isolated human groin lymphatics
- 1989
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Ingår i: Lymphology. - 0024-7766. ; 22:3, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- In vitro studies were performed on lymphatics obtained from the groin in 19 patients undergoing vascular surgery. The lymphatics were mounted in tissue baths, and isometric contractions were induced by increasing concentrations of the thromboxane A2 (TXA2) mimetic U-46619. In comparison to K+ (124mM)-induced contraction, which were used as an internal standard, the response to U-46619 had an Emax of 105 +/- 5.9%. The pEC50-value was 8.14 +/- 0.09. The effects of two thromboxane receptor (TP-receptor) antagonists, L-636,499 and BM-13,505, were investigated. Both antagonists caused concentration-dependent right-ward shifts without depression of Emax of the U-46619 concentration-response curves. The slopes of the regression lines in a Schild plot for both antagonists did not differ from one, indicating competitive antagonism. The pA2-value of BM-13,505 (7.89) was 65 times higher than that of L-636,499 (6.08). The results suggest that the receptor involved in the prostanoid contraction in human groin lymphatics is of the TP-subtype.
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| 2. |
- Sjöberg, Trygve, et al.
(författare)
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Comparative effects of the alpha-adrenoceptor agonists noradrenaline, phenylephrine and clonidine in the human saphenous vein in vivo and in vitro
- 1989
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 136:3, s. 463-471
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Tidskriftsartikel (refereegranskat)abstract
- The alpha-adrenoceptor-mediated contractile effects of noradrenaline (alpha 1 + alpha 2), phenylephrine (alpha 1) and clonidine (alpha 2) on human saphenous veins were investigated in vivo and in vitro. By infusion (0.3 ml min-1) of the drugs (increasing concentrations in the infused solution) into distended (40 mmHg) saphenous veins in six healthy subjects, local vasoconstriction was induced, measured by a photo-electric device. The drugs induced dose-dependent contractions in all subjects, and dose-response curves were constructed. These were compared with concentration-response curves based on in-vitro results. Macroscopically normal saphenous veins, taken at saphenousectomies, were used, and the preparations were contracted isometrically in organ baths by the agonists. From the curves obtained in vivo and in vitro, the relative potencies of phenylephrine and clonidine (in relation to noradrenaline) were calculated and compared. The relative potencies of phenylephrine in vivo (76%) and in vitro (82%) did not differ significantly. However, the relative potency of clonidine was significantly (P less than 0.05) lower in vivo (90%) than in vitro (99%). Thus, it is concluded that there are differences between the results obtained in vivo and in vitro, stressing the importance of comparative in vivo-in vitro studies.
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| 3. |
- Sjöberg, Trygve, et al.
(författare)
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Contractile response in isolated human groin lymphatics
- 1987
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Ingår i: Lymphology. - 0024-7766. ; 20:3, s. 152-160
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Tidskriftsartikel (refereegranskat)abstract
- Lymphatics from the human superficial groin removed at operation in 21 patients (one with lymphedema) were examined in vitro. Histochemically no nerves were identified with either specific catecholamine fluorescence or immunoreactivity to tyrosine hydroxylase or dopamine beta-hydroxylase. Ring preparations of the lymphatics were mounted in tissue baths and isometric induced contractions were recorded after administration of K+ (124 mM), acetylcholine, selected amines and prostanoids. Noradrenaline (NA), adrenaline, dopamine, and acetylcholine had no or only weak contractile effects. In some segments, serotonin induced contractions. Prostaglandin E2 showed no contractile effect and prostaglandin F2 alpha induced contraction in most of the tested lymphatics. The prostaglandin-endoperoxide analogue U44069 uniformly elicited marked concentration-dependent contraction. In the lymphatic segment from the patient with lymphedema, a slightly greater contractile response to NA and serotonin was observed. The results overall suggest an absence of sympathetic innervation and contraction-mediating alpha adrenergic receptors in human superficial groin lymphatics, and support that certain prostanoids may be important regulators of human lymphatic contractility.
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| 4. |
- Sjöberg, Trygve, et al.
(författare)
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Contractility of human leg lymphatics during exercise before and after indomethacin
- 1989
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Ingår i: Lymphology. - 0024-7766. ; 22:4, s. 186-193
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Tidskriftsartikel (refereegranskat)abstract
- Subcutaneous lymphatics in the lower leg were catheterized in the retrograde direction in 6 healthy male subjects. The catheter was connected to a pressure transducer, and pressure was measured during three stages of exercise including standing, tip-toeing, and running in place. Before the third stage, indomethacin (50mg) was given i.v. Rhythmic pressure waves were registered in each subject. During the second stage, when the subjects were "warmed up," the frequency (min-1) was 2.4 +/- 0.5 (mean +/- SEM). The corresponding values during tip-toeing and running were 5.8 +/- 0.7 (p less than 0.05) and 5.4 +/- 0.5 (p less than 0.05), respectively. The amplitudes (mean values between 3.2-4.7mmHg while standing) were not consistently altered during tip-toeing or running in any of the three stages. During standing there was a negative correlation between frequency and amplitude. No such correlation was found during tip-toeing or running, or after injection of indomethacin. Indomethacin did not significantly alter any of the measured parameters, but in two subjects the frequencies and amplitudes were decreased (about 50%) during standing, tip-toeing, and running.
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| 5. |
- Herbst, Andreas, et al.
(författare)
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Infections and antibiotic prophylaxis in reconstructive vascular surgery
- 1989
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Ingår i: European Journal of Vascular Surgery. - 0950-821X. ; 3:4, s. 303-307
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Tidskriftsartikel (refereegranskat)abstract
- In 98 patients undergoing elective vascular surgery, specimens for bacterial cultures were obtained from urine, ischaemic ulcers, incisional wounds and the implanted grafts. Wound and graft infections were registered and compared with the results of these cultures and suspected risk factors in an attempt to find the source of infections. Antibiotic prophylaxis with cefuroxime was given for 24 h beginning at the start of surgery. Patients with ischaemic ulcers also received "spread prophylaxis", directed against isolated bacteria, for ten days. Three cases of graft infection and twelve cases of wound infection occurred. Positive postoperative cultures from wounds did not correlate with pre- or peroperative cultures. Peroperative cultures revealed small numbers of staphylococcus epidermidis in eleven patients, and none of them developed graft infection. Ischaemic ulcers, diabetes or re-do procedures were not accompanied by a significantly increased frequency of wound or graft infection, although each of three patients with graft infection had one of these risk factors. Bacteria, sensitive to cefuroxime, were found in one graft infection, six wound infections, and in two patients with urosepsis, whereas cefuroxime resistant organisms were isolated from one graft infection and three infected wounds. One of the three graft infections was probably caused by bacteria originating from the patient's ischaemic ulcer. In the other two patients the source of bacteria could not be determined. Cefuroxime seems to be an adequate alternative for prophylaxis of vascular graft infection, but in some patients with bacteriuria or indwelling catheters, a one day regimen may be too short.
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| 6. |
- 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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