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Fluorescent probes were used to visualize the morphology of membranes and of F-actin in rat peritoneal mast cells, exposed to hyperosmotic medium and consequently reversed to isotonicity. Hypertonicity induced cell shrinkage followed by a... more
Fluorescent probes were used to visualize the morphology of membranes and of F-actin in rat peritoneal mast cells, exposed to hyperosmotic medium and consequently reversed to isotonicity. Hypertonicity induced cell shrinkage followed by a regulatory volume increase, and cell alkalinization that was sensitive to amiloride, an inhibitor of the Na(+)/H(+) exchanger (NHE), but not to Latrunculin B, an inhibitor of actin polymerization. Using Bodipy-Sphingomyelin, we have observed formation of vacuole-like dilations (VLDs), primarily at or close to the adhesion plane, following the reversal from hyper- to isotonic medium. VLD formation was not inhibited by Latrunculin B or by amiloride. Phalloidin staining has shown that actin filaments do not surround the vacuoles and latrunculin-induced depolymerization of actin has actually promoted vacuole formation, even in isotonic conditions. The results support the idea that a decrease in membrane tension promotes the internalization of the plasma membrane.
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Research Interests: Biomedical Engineering, Humans, Female, Male, Clinical Sciences, and 4 moreAged, Middle Aged, Adult, and Prognosis
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The Na+/K(+)-pump activity and the utilization of adenosine triphosphate (ATP) were studied in rat peritoneal mast cells after histamine secretion induced by compound 48/80. We measured the ouabain-sensitive K(+)-uptake by a radioactive... more
The Na+/K(+)-pump activity and the utilization of adenosine triphosphate (ATP) were studied in rat peritoneal mast cells after histamine secretion induced by compound 48/80. We measured the ouabain-sensitive K(+)-uptake by a radioactive technique (86Rb+). The ATP content and the glycolytic ATP-production were measured by the bioluminescence technique (firefly lantern) and by measurement of the lactate production under anaerobic conditions (antimycin A, oligomycin), respectively. There was an increased requirement for ATP after the secretory response associated with an increased activity of the Na+/K(+)-pump. The anaerobic, but not the aerobic, pathway for ATP-synthesis was able to respond to the increased ATP-requirement. The ATP-requirement of the Na+/K(+)-pump was only partly satisfied when ATP was supplied from either the glycolytic or the oxidative pathway. This may indicate that the availability of ATP was the limiting factor for the activity of the Na+/K(+)-pump following histamine secretion under these conditions. It is concluded that the large increase in Na+/K(+)-pump activity after a secretory response is a likely explanation for the long lasting ATP-decrease in mast cells that follows histamine secretion.
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Ten patients with liver cirrhosis undergoing portocaval shunt operation have been followed immunologically during their postoperative course regarding antibody titres to various antigens, viral as well as bacterial. The antibody... more
Ten patients with liver cirrhosis undergoing portocaval shunt operation have been followed immunologically during their postoperative course regarding antibody titres to various antigens, viral as well as bacterial. The antibody determinations included rubella, vaccinia and cytomagalo viruses, diptheria toxoid, Candida albicans, streptolysin O, typhoid and paratyphoid O and H and the syphilis reactions: Kahn, Wassermann and Meinicke. Twenty-one blood donors served as controls. Skin test reactions to diptheria, Candida albicans, streptokinase and tuberculin were performed on the same patients. Eight patients submitted to cholecystectomy served as controls for pre-and postoperative skin tests and antibody titres. The liver cirrhosis group before operation had a significantly higher number of elevated antibody titres concomitant with a significantly reduced skin test reactivity to diphtheria toxoid and streptokinase. An increase in the number of elevated antibody titres was seen after portocaval shunt operation. In no case was a higher antibody titre associated with an increase in skin reactivity to the corresponding antigen. A number of significant titre changes to viral antigens were seen in the postoperative course without clinical evidence of the corresponding viral disease. Thes findings indicate that under certain circumstances antibody titre changes should be interpreted with caution.
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Nocodazole depolymerized microtubules and increased the number of microfilaments, and dimethylsulfoxide increased the number of microfilaments. Both drugs inhibited compound 48/80-induced histamine release from rat mast cells. Taxol,... more
Nocodazole depolymerized microtubules and increased the number of microfilaments, and dimethylsulfoxide increased the number of microfilaments. Both drugs inhibited compound 48/80-induced histamine release from rat mast cells. Taxol, which increased the number of microtubules, had no effect on histamine release. These observations support the view that microtubules may not be directly involved in secretion, but apparently an increased number of microfilaments is associated with a decreased capacity of the mast cells for histamine release. We suggest that microfilaments have to be depolymerized or rearranged before secretion can take place.
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Lymphocytes were used as a cellular model for the in vitro measurements of 22Na+-influx during sodium pump inhibition by ouabain. The measurements were made using lymphocytes from young men at increased risk of developing essential... more
Lymphocytes were used as a cellular model for the in vitro measurements of 22Na+-influx during sodium pump inhibition by ouabain. The measurements were made using lymphocytes from young men at increased risk of developing essential hypertension in order to assess any changes and to analyse whether any such changes were associated to borderline hypertension and/or heredity. Four groups were evaluated: 28 normotensive and 20 borderline hypertensive offspring of hypertensives, 12 borderline hypertensives and 28 normotensives with normotensive parents. 22Na+-influx was significantly increased in offspring of hypertensive parents especially in the normotensive offspring of hypertensive parents. The association between heredity and increased 22Na+-influx found by us in vitro may be caused by either an increased passive sodium-influx and/or an increased sodium-sodium exchange mechanism.
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The purpose of this study was to examine how intracellular pH (pHi) regulation and histamine release are affected by HCO3- in rat peritoneal mast cells. The pHi was measured using the pH-sensitive dye 2',... more
The purpose of this study was to examine how intracellular pH (pHi) regulation and histamine release are affected by HCO3- in rat peritoneal mast cells. The pHi was measured using the pH-sensitive dye 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). We observed a pHi of 6.88+/-0.012 (n=24) in resting mast cells exposed to a HEPES buffer (pH 7.4), but a sustained drop of 0.21 pH units to 6.67+/-0.015 (n=23) when we exposed the mast cells to a HEPES/HCO3- buffer equilibrated at all time with 5% CO2 (pH 7.4). This fall in pHi is inhibited by the carbonic anhydrase inhibitor dichlorphenamide and is Na+-independent, indicating the involvement of Na+-independent Cl-/HCO3- exchange activity. Furthermore removal of external Cl- in the presence but not in the absence of HCO3- reversed the Cl-/HCO3- exchange and induced an alkaline load. The recovery from this alkaline load was dependent on external Cl- but independent of Na+. Both the alkalinization and the recovery were inhibited by the anion transport inhibitor 4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). In addition, 36Cl- uptake measurements confirm the presence of a Cl-/HCO3- exchanger. Histamine release stimulated by antigen and compound 48/80 was substantially reduced in the presence of HEPES/ HCO3- buffer (pHo 7.4, pHi 6.66). Histamine release was increased, however, when pHi was clamped to 6.66 in HCO3--free media (pHo 6.9). We conclude that: (1) Na+-independent Cl-/HCO3- exchange determines steady-state pHi in rat peritoneal mast cells; and (2) the reduction in histamine release observed in the presence of HCO3- is not due to its effect on pHi per se, but rather on other changes in ion transport.
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... References. 1. RP Rubin; Pharmac. Rev., 22 (1970), pp. 389–428. ... 2. JC Foreman, JL Mongar; J. Physiol., 224 (1972), pp. 753–769. ... 3. B. Uvnäs, I.-L. Thon; Exp. Cell. Res., 23 (1961), pp. 45–57. ... 4. LG Garland, AN Payne; Br.... more
... References. 1. RP Rubin; Pharmac. Rev., 22 (1970), pp. 389–428. ... 2. JC Foreman, JL Mongar; J. Physiol., 224 (1972), pp. 753–769. ... 3. B. Uvnäs, I.-L. Thon; Exp. Cell. Res., 23 (1961), pp. 45–57. ... 4. LG Garland, AN Payne; Br. J. Pharmac., 65 (1979), pp. 609–613. ... 5. T. Johansen; ...
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Nine knees with persistent radiographic depression of the articular surface after tibial plateau fractures treated by traction and early knee motion were examined using magnetic resonance imaging (MRI). The MRI examinations demonstrated... more
Nine knees with persistent radiographic depression of the articular surface after tibial plateau fractures treated by traction and early knee motion were examined using magnetic resonance imaging (MRI). The MRI examinations demonstrated that the radiographic bone defects were filled up with different tissues, which we interpreted as cartilage, fibrous tissue and synovial plica. The type of tissue in the bone defect did not seem to affect the functional capabilities of the knee. However, a demonstrable thin cover of tissue, with the signal-intensity of cartilage, over the defect, seemed to be associated with an excellent functional result.
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ABSTRACT