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Biomedical subjects

U Bagge

Publications and source records attributed to U Bagge.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effects of cooling after scald injury to a dorsal skin fold of mouse.

Shaved trunk skin folds of hairy mice were scalded for 20 s by water immersion. In one set of experiments the effect of increasing burn temperature (51 degrees C-60 degrees C) was studied, in another the folds were first scalded at 51 degrees C-54 degrees C and then immediately cooled for 30 min in 8 degrees C water. Animals were killed 2 h and 4 days postburn. Before sacrifice, Evans blue was injected i.v. to some animals to visualize preserved vascular perfusion and areas of increased permeability. Macroscopic observations (and photographic documentation) were made of the outside and inside of the injured skin and biopsies for light microscopy were obtained centrally in the burns. The injured area was measured by planimetry on photographs and expressed in percent of the whole burned area. At 4 days, brownish, oval areas appeared on the skin being progressively larger with increasing burn temperature. The 51 degrees C burn only resulted in a very small, spotlike, tissue injury, while the greater than or equal to 52 degrees C produced a macroscopic necrosis amounting to 40%-94% of the burned area. Postburn cooling did not reduce the damaged area as recorded 4 days postburn. Histologically, the tissues seemed well preserved at 2 h after 51 degrees C scalds, whereas cell damage was obvious and increasingly pronounced after greater than or equal to 53 degrees C burns. After 52 degrees C burns a mixed picture emerged. A similar microscopic pattern was seen at 4 days; 51 degrees C specimens were undamaged, some 52 degrees C and all greater than or equal to 53 degrees C were necrotic.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1985

Proliferative synovitis in rabbit knee joints induced by antigen and preformed immune complexes.

Knee joints of non-immunized rabbits were repeatedly injected with bovine serum albumin (BSA) and preformed BSA-anti-BSA immune complexes which had differing precipitation profiles and abilities to activate complement. Ten days after the last of six injections the antibody and lymphoproliferative responses to BSA were analysed and correlated to the degree of arthritis. Joint swelling, increased numbers of joint fluid leukocytes and morphological changes typical of proliferative synovitis were found only in those rabbits injected with a large dose of antigen or with immune complexes prepared in antigen excess of poor precipitation and complement-activating properties in vitro. The degree of arthritis correlated with the development of humoral and lymphoproliferative immune responses to BSA.

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PubMed1985

Microscopic studies on the influence of erythrocyte concentration on the post-junctional radial distribution of leukocytes at small venular junctions.

The influence of flow patterns and erythrocyte concentration on the post-junctional radial position of leukocytes was studied in microvascular junctions in an isolated mesocaecum preparation and in vivo in the rat cremaster muscle. Main branch and side branch dimensions (mesentery) were approximately 60 micrograms and approximately 20 micrograms, respectively. For the analysis the main branch was divided into three equally wide sectors. Firstly, the observations indicate that the main branch and side branch flows remain separated downstream of a junction and, secondly, that the blood cells mainly leave the junction within their original streams. At zero hematocrit 71-87.5% of the leukocytes from the side branch flowed in the closest main branch sector; 12.5-29% reached the central sector-the lowest numbers were seen in the central sector when the flow velocity ratio, main branch-side branch was 2:1. No cells became marginated. At 20% and 40% hematocrit, all leukocytes from the side branch flowed in the closest main branch sector. Marginated leukocytes in the side branch or upstream in the main branch remained marginated only if passing the junction on the uninterrupted wall. In the cremaster muscle, 3-capillary confluences were studied. The blood from the capillaries seemed to flow in three separate streams in the venule. Since these streams were narrower than those observed in the mesentery, the leukocytes in the capillaries producing the peripheral streams continued to flow in contact with the vascular wall, i.e. they became marginated in the venules without any lateral movement. On the basis of this study and previous work it is proposed that the radial position of leukocytes downstream of a junction is determined not only by leukocyte-erythrocyte interactions but also by the specific flow patterns that arise in microvascular confluences.

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PubMed1984

The importance of 5-HT for tumor cell lodgement in the liver.

Arrest and lodgement of circulating tumor cells in the microvasculature is a prerequisite for metastasis formation. Aggregation of activated platelets and subsequent release of bioactive substances seem to influence the lodgement process. Since thrombocytopenia has been shown to reduce lodgement and since 5-HT is one of the compounds released from activated platelets, the present investigation was directed toward the influence of this amine on tumor cell lodgement in the liver after intraportal injection of fibrosarcoma cells. Lodgement was quantitated by an isotope technique with simultaneous measurements of 5-HT levels by a LCEC technique in rat liver biopsies from areas with lodged tumor cells as observed with vital fluorescence microscopy. To test the importance of 5-HT released from platelets, thrombocytopenia was induced with anti-platelet serum in one experimental group, while animals in another group were treated with ketanserin (a selective 5-HT2 receptor blocking agent). Animals given tumor cells alone showed a two-fold increase in 5-HT levels compared with animals injected with saline, indicating a relation between 5-HT release and tumor cell lodgement. In thrombocytopenic animals lodgement was reduced to 53% (5-HT levels reduced to 50%) of tumor-cell-injected controls. Ketanserin treatment reduced tumor cell lodgement to 72% (5-HT levels to 63%). The results indicate that 5-HT is one of the substances released from activated platelets and that 5-HT is involved in tumor cell lodgement.

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PubMed1984

Inhibitory effect of honey bee venom on immune complex mediated leukocyte migration into rabbit knee-joints.

The anti-inflammatory effect of purified honey bee venom (HBV) was studied using a recently described animal model in which preformed immune complexes were injected into rabbit knee-joints. As little as a single injection of 1.2 micrograms HBV/kg body weight subcutaneously significantly reduced the immune complex induced joint inflammation as measured by reduction in leukocyte counts in the joint fluid. This decrease was obvious 3 and 6 but not 9 hours after induction of the inflammation. There was no significant effect on leukocyte random migration, chemotactic responsiveness or phagocytosis, indicating that HBV did not interfere with normal phagocyte motility and ingestion. The modifying effects by HBV on the inflammatory response to immune complexes in vivo is most likely due to interference with other components of the inflammatory response.

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PubMed1984

Quantitative studies on the influence of leukocytes on the vascular resistance in a skeletal muscle preparation.

The effects of leukocytes on vascular resistance and capillary filtration coefficient (CFC) of the maximally vasodilated vascular bed of rat hindquarters were measured using servocontrolled isogravimetry . After determination of the pre- and postcapillary resistances and CFC with a cell-free perfusate, a leukocyte bolus was introduced (0.5 to 9 X 10(6) cells/100 g tissue). Experiments were performed at three flows: 0.7-0.9, 1.4-1.6, and 2.4-3.7 ml/(min X 100 g tissue). Changes in vascular resistance were calculated from continuous pressure-flow recordings during a 10-min period, followed by a CFC measurement. Leukocytes were counted in the effluent for calculation of the number of cells remaining in the vascular bed. Leukocyte infusion caused a transient increase of the precapillary resistance (Ra) by as much as 72% after infusion of 9 X 10(6) cells/100 g tissue at 0.7-0.9 ml/(min X 100 g tissue). After the initial peak the Ra usually fell to a lower, constant, level, but was still clearly elevated (maximum 23%) at the low flows of 0.7-0.9 and 1.4-1.6 ml/(min X 100 g tissue). This sustained increase of Ra was positively related to the number of cells remaining in the vasculature. At high flows of 2.4-3.7 ml/(min X 100 g tissue) the Ra increase was very small, irrespective of the number of cells infused or remaining in the vascular bed. These findings, together with the fact that CFC decreased proportionally to the sustained increase of Ra, indicate that the effect of leukocytes on Ra was due to a pressure-dependent occlusion of the microvasculature.

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PubMed1984

Postburn blood flow, edema, and survival of the hairy mouse ear after scald injury at different temperatures.

In one group (a) one ear of NMRI hairy mice was scalded in water at 36 degrees C, 39 degrees C, 42 degrees C, 45 degrees C, 48 degrees C, 51 degrees C, 52 degrees C, 53 degrees C, 54 degrees C, 57 degrees C, and 60 degrees C for 20 s, using a new dip burn model, for evaluation of edema formation 2 h postburn. In another group of mice (b) one ear was scalded in the 45 degrees C-60 degrees C interval and the ear studied in a vital microscope repeatedly for 4 days. In a third group (c), one ear was scalded in the 36 degrees C-60 degrees C interval and the microcirculatory flow was recorded by a laser Doppler flowmeter (1Df) for a period of 2 h postburn. In a fourth group of animals (d) one ear was scalded at 53 degrees C or 54 degrees C. In some animals the ear was then cooled in 8 degrees C water or saline for 30 min. Others were treated preburn with cimetidine, Ketanserin, indomethacin or methylprednisolone. Edema was determined in group (a) by wet-dry weight measurements of punch biopsies from both the burned and the contralateral unburned ear and expressed as an increase in tissue water content. The long-term effect was determined by observing the survival of the ears (groups b and d); the area of necrosis was expressed as a percentage of the total area of the ear. Significant edema was formed in ears immersed in 48 degrees C to 60 degrees C water with a maximum after 53 degrees C burns.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1983

The effect of thrombocytopenia and antiserotonin treatment on the lodgement of circulating tumor cells. A vital fluorescence microscopic, electron microscopic and isotope study in the rat.

The hepatic lodgement of intraportally injected fibrosarcoma cells was analysed with a combination of vital fluorescence microscopic, electron microscopic and isotope techniques in normal, thrombocytopenic and antiserotonin treated (Ketanserin) rats. Ketanserin had no effect on the initial arrest of the tumor cells, as measured 5 min after tumor cell injection, which is in analogy with our previous results on thrombocytopenia. Three hours after injection, the number of lodged tumor cells was significantly reduced by both thrombocytopenia and Ketanserin treatment. Thrombocytopenia was more efficient in reducing tumor cell lodgement than antiserotonin treatment. The in vivo and electron microscopic observations indicated that the reduction of tumor cell lodgement was due to an increased destruction of tumor cells. The similar effects of Ketanserin and thrombocytopenia suggest that serotonin, when released from platelets activated in the presence of tumor cells, increases the survival of fibrosarcoma cells lodged in the liver.

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PubMed1983

The arrest of circulating tumor cells in the liver microcirculation. A vital fluorescence microscopic, electron microscopic and isotope study in the rat.

Previous studies have shown that thrombocytopenia reduces the lodgement of circulating tumor cells, thus indicating a role of platelets in tumor cell lodgement. In this study, a vital fluorescence microscopic technique, electron microscopy and isotope measurements were combined to analyse the very first phase (5 min) of tumor cell lodgement using a syngeneic, methylcholantrene induced fibrosarcoma. The mode of tumor cell arrest in the liver microvasculature of normal and thrombocytopenic rats was studied. In addition, tumor cell size and deformability were investigated in vitro. The in vitro experiments showed that the fibrosarcoma cells were very rigid. Both the vital microscopic and electron microscopic studies indicated that the tumor cells mainly became arrested by mechanical trapping in narrow liver sinusoids. Arrest of tumor cells by adherence to venular walls was a rare finding. Platelets did not seem to influence any of these initial phenomena of tumor cell lodgement. The isotope measurements, which showed no difference in the number of tumor cells lodged in the liver between normal and thrombocytopenic rats, further indicated that the initial arrest of the fibrosarcoma cells was not influenced by platelets.

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PubMed1983

The influence of antiserotonin treatment with ketanserin on the pulmonary lodgement of circulating tumour cells in normal and traumatized rats.

As shown in earlier studies, the lodgement of circulating tumour cells in the lungs is reduced by thrombocytopenia in both normal and traumatized rats. Other experiments have shown that thrombocytopenia and antiserotonin treatment with ketanserin, which has a selective effect on 5-HT2 receptors, decrease the hepatic lodgement of intraportally injected tumour cells. The present studies show that treatment with ketanserin also reduces the lodgement of i.v.-injected tumour cells in the lungs in both normal and traumatized rats.

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PubMed1983

The influence of locally deposited fibrin on the biomechanical properties of developing granulation tissue in rats.

A recently developed method for the occlusion of fistulas with a fibrin clot has stimulated studies concerning the effects of deposited fibrin on the formation of granulation tissue (g.t.). In this study the influence of artificially implanted fibrin on the biomechanical properties of developing g.t. was investigated in rats. Perforated Teflon cylinders either empty or fibrin filled, were implanted subcutaneously for two weeks. The g.t. from fibrin filled cylinders was found to adhere significantly better to the cylinder walls which is an important property in the case of fistula closure with fibrin. Mechanical testing, however, showed that the maximum load and the maximum strain were significantly higher in cylinders implanted empty. However, the collagen concentration was no higher in cylinders implanted empty suggesting that in the newly formed g.t. studied, factors other than the collagen concentration determined the strength of the tissue.

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PubMed1983

Ultrastructural observations on endothelial cell vesicles after horseradish peroxidase microinjection into blood and dextran perfused microvessels of rat mesentery.

Horseradish peroxidase (HRP) was injected for 5 sec into the arteriole that supplies the mesocecum in rats. This microperfusion was followed by fixation (with arrest of blood flow in 203 sec) either immediately or after an interval of 10 sec, 20 sec, 60 sec, or 120 sec and a diaminobenzidine cytochemical processing of the tissue was performed. The distribution of HRP was determined in the electron microscope. After immediate fixation HRP labelled 93% of luminal endothelial vesicles, 45% of cytoplasmic, closed vesicles and 4% of the abluminal ones but from 10 sec later virtually no labelling was seen. This finding seems best explained by a vesicular organization where most vesicles communicate with the extracellular space, directly or via other vesicles. However, a few observations of isolated labelled abluminal vesicles, even opposite endothelial cell nuclei already after 5 sec HRP exposure, indicate that classical vesicular transport in quanta also occurs. The same microvasculature was observed after 2 min artificial perfusion with 3% dextran 70 in Tyrode solution with or without 0.2% albumin followed by 5 sec HRP and fixation. In the absence of albumin HRP labelled vacuole-like vesicles and deep-penetrating clusters of vesicles in the endothelium. Moreover, isolated large vesicles and probably also vesicular conglomerates formed transendothelial channels. It is suggested that vesicular conformational changes might contribute to the permeability increasing effect of protein-free perfusion.

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PubMed1983

The initiation of post-capillary margination of leukocytes: studies in vitro on the influence of erythrocyte concentration and flow velocity.

Leukocyte margination is an important rheological phenomenon, being a prerequisite for leukocyte adhesion and invasion of the tissues in inflammation. In the present study the influence on leukocyte radial distribution of erythrocyte concentration and flow velocity was studied with fluorescence microscopy in a glass capillary model. This consisted of a narrow (10 microns) short stenosis expanding into a 50 microns straight tube. The blood cells were brought to the centre of the stream by the stenosis whereas the radial position of the leukocytes was determined in the straight post-stenotic segment of the glass tube. The analyses showed that a 0 hematocrit 86% (flow velocity 0.2 mm/s) to 99% (flow velocity 1.2 mm/s) of the leukocytes stayed in the centre of the tube after leaving the stenosis. No leukocytes were observed at the capillary wall. At 10% hematocrit and low flow velocity, 0.1 and 0.3 mm/s, 36 and 34%, respectively, of the leukocytes were displaced to a marginal position. At 1.0 mm/s only 10% of the leukocytes were displaced from the central stream. At 40% hematocrit, 45, 47 and 40% of the leukocytes were found in a wall near position at 0.1, 0.4 and 0.7 mm/s flow velocity, respectively. Although the results obtained in the present study are valid only for the special geometry of the in vitro model they clearly indicate the importance of leukocyte-erythrocyte interactions for the initiation of leukocyte margination in post-capillary vessels.

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PubMed1983

The kinetics of leucocyte migration into rabbit knee joints elicited by preformed immune complexes with different in vitro characteristics.

Immune complexes were formed in vitro with antibodies obtained from rabbits immunized with bovine serum albumin in Freund's complete (FCA) or incomplete (FIA) adjuvant. The antibodies were mixed with different amounts of antigen. Immune complexes formed at maximum precipitation proportions were efficient in complement activation, whereas immune complexes formed at antigen excess had weak complement-activating properties. When injected into rabbit knee joints, the immune complexes formed at maximum precipitation proportions with FCA or FIA antibodies caused a moderate leucocyte migration into the joints with maximum cell counts 6-8 hr after injection. Injection into the joints of immune complexes formed with FCA antibodies at antigen excess induced a pronounced leucocyte migration with maximum numbers 18 hr after injection. Immunofluorescent studies indicated that these immune complexes became associated with the leucocyte membrane, whereas immune complexes formed at maximum precipitation proportions were found in the leucocyte granulae, indicating that only the complement-activating immune complexes were efficiently eliminated.

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PubMed1982

Effect of cold water immersion on oedema formation in the scalded mouse ear.

One ear of adult white NMRI hairy mice was first scalded and then immersed in cold water in order to study the effect of cooling on oedema formation. Oedema was determined by wet-dry weight measurements of punch biopsies from the ear and expressed as an increase in tissue water content. The temperature of the cold water was 8 degrees C and periods of cooling from 15 to 240 minutes were used. The contralateral ear and the quadriceps muscle were used to study distant effects of scalding and cooling. After scalding, significant oedema was found in the burned ear. Cooling for 30 minutes gave a significant reduction of oedema in this model. Shorter or longer periods of cooling did not reduce oedema significantly. Cooling did not influence the oedema formation of the contralateral (unburned ear). Neither scalding nor cooling changed the water content of the muscle.

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