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Biomedical subjects

L Karlsson

Publications and source records attributed to L Karlsson.

At least 127 records · Page 7Linked to original sources
PubMed1984

Intratumor distribution of capillary permeability surface area product (PS) correlated to tumor vascular space and blood flow.

The intratumor distribution of the capillary permeability surface area product (PS) correlated to the intratumor distribution of vascular space and of blood flow was studied by labeled albumin in a transplantable rat fibrosarcoma. A wide heterogeneity in intratumor distribution of PS was found. The tumor PS values were not significantly correlated to tumor vascular space or to blood flow values. This might suggest that intravascularly administered drugs could reach a comparative high intratissue concentration also in less vascularized tumor areas.

Albumins↗
PubMed1983

Reduction of gastric haemorrhage by fibrinolysis inhibition - an experimental study in rats.

Gastric ulcerations were induced in rats by pyloric ligature and instillation of 1.0 N HCl. After four hours all rats had developed ulcerations. Increased release of plasminogen activators from the mucosa during these conditions has previously been demonstrated. In the present study we investigated the role of fibrinolysis inhibition versus H2-receptor blockade on the gastric bleeding. Tranexamic acid - a synthetic inhibitor of the fibrinolytic system - was found to significantly (p less than 0.01) reduce blood loss into the gastric juice by 30% measured by 51Cr labelled red blood cells; cimetidine did not reduce the gastric haemorrhage under the experimental conditions used. Both treatment regimes significantly (p less than 0.02) reduced the secretion of gastric juice. These results indicate a contribution of the fibrinolytic system in gastric bleeding from experimentally induced gastric ulcerations.

Animals↗
PubMed1983

Influence of vasoactive drugs on the intratumor distribution of blood flow and vascular volume in a transplantable rat fibrosarcoma.

The intratumor distribution of plasma volume and of blood flow was studied simultaneously by radioisotope techniques in a transplantable rat fibrosarcoma. Intravenous administration of norepinephrine changed the distribution of both plasma volume and blood flow to produce low values in tumor and in normal muscle. Intravenous administration of papaverine was surprisingly followed by similar effects, probably due to a direct influence of papaverine on cardiac function. Intraaortal administration of papaverine into the studied tissue area did not influence tumor blood flow or plasma volume but increased normal muscle plasma volume. The results might support a previously suggested possibility that one can directly influence the tumor vascular bed with vasoconstricting drugs, while tumor vessels are more resistant to pharmacologic dilatation probably because of their normal state of close to maximal dilatation.

Animals↗
PubMed1982

Enrichment of epidermal Langerhans cells: studies with a monolayer technique and flow cytometry sorting.

Langerhans cells were enriched from epidermal cell suspensions by a monolayer technique based on the association of Langerhans cells with solid matrix-bound anti-Ia antibodies or by flow cytometry sorting of fluorescein-isothiocyanate labeled anti-Ia reactive cells. The monolayer technique gave a moderate enrichment (15-37%) whereas considerably higher purity (73-87%) was obtained by flow cytometry sorting. The identity of the enriched anti-Ia reactive cells as Langerhans cells was established by histochemical techniques or electron microscopy. The monolayer-enriched Langerhans cells could function as stimulating cells in the mixed leukocyte culture reaction and as antigen-presenting cells.

Animals↗
PubMed1981

Inhibition of tumour vascularization by tranexamic acid. Experimental studies on possible mechanisms.

The vascularization of an intramuscularly transplanted rat sarcoma was studied by microangiography. Administration of tranexamic acid as well as of indomethacin reduced the vascular connections between tumour and surrounding normal muscle. These drugs also reduced tumour growth rate irrespective of whether they were administered early or late during tumour growth. An electron microscopy study of tumour specimens from animals given tranexamic acid did not reveal any degenerative vascular changes. One explanation of the inhibition of tumour growth and vascularization by tranexamic acid and by indomethacin may be reduction of a local inflammatory reaction induced by tumour transplantation and stimulating tumour vascularization.

Angiography↗
PubMed1981

Influence of tranexamic acid on tumour blood flow.

The influence on the intratumour blood flow distribution in a transplantable rat sarcoma by a potent antifibrinolytic drug, tranexamic acid, administered intraperitoneally for 3 or 10 days was studied by the intratumour distribution of intravenously injected 86Rb. A local Xenon clearance technique was used to study the direct effect of tranexamic acid on local tumour blood flow. local tumour blood flow and the intratumour blood flow distribution after administration of tranexamic acid for 3 days were unchanged compared to controls. Prolonged administration of tranexamic acid changed the intratumour blood flow distribution significantly towards low flow values. This might be one mechanism behind the inhibiting effect of tranexamic acid in tumour growth rate, previously observed in both experimental and clinical studies.

Animals↗
PubMed1980

Intratumor distribution of blood flow and of vascular volume in a transplantable rat sarcoma.

The intratumor distribution of plasma volume and of blood flow was studied simultaneously by radioisotope techniques in a transplantable, slightly differentiated 20-methylcholanthrene-induced rat sarcoma. A significant change toward lower tumor blood flow was found in the sarcoma with increasing tumor growth, accompanied by a reduced plasma volume. The distributions of plasma volume and blood flow were similar in peripheral and central parts of tumors. However, no significant correlation between plasma volume and blood flow was found in separate tumor specimens.

Animals↗
PubMed1978

Studies on toxemia of pregnancy with special reference to blood pressure. I. Incidence and some characteristic features of the mothers and infants.

An investigation was made of 150 women who were diagnosed at the Department of Obstetrics and Gynaecology, University Hospital, Uppsala in 1964-68 as having toxaemia of pregnancy. Eleven had eclampsia and the remainder pre-eclampsia. Toxaemia occurred in 0.88% (average) of all parturients during the study period. Some characteristics of the mothers and their infants are reported. Thus, there were more instrumental deliveries in the toxaemia group than in the non-toxaemic patients delivered in the clinic. The maternal weight at delivery was also greater in the toxaemia group. The frequency of complications among the infants was higher in the group with toxaemia. There were more stillbirths, lower birth weights and more congenital malformations. With regard to blood pressure, almost identical pressures were noted in the eclamptic and pre-eclamptic groups, with one exception. The maximum blood pressure recorded during delivery was higher in the eclamptic than in the pre-eclamptic group (198/127 and 175/117).

Birth Weight↗
PubMed1978

Studies on toxaemia of pregnancy with special reference to blood pressure. II. Results after 6-11 years' follow-up.

One hundred and fifty women with a diagnosis of toxaemia of pregnancy treated in the Department of Obstetrics and Gynaecology, University Hospital, Uppsala between 1964 and 1968 were investigated. One hundred women were still living in the area in 1975 and thus could be restudied. The participation rate was 100% in this group. After this follow-up period of 6-11 years 17 women were hypertensives at the investigation and 12 were already on antihypertensive therapy. The incidence of hypertension was thus 29%. The toxaemic women who had developed gypertension showed a higher frequency of a family history of hypertension as well as of cardiovascular lesions than the toxaemic women with normal blood pressures at follow-up. At the time of the toxaemia the future hypertensive women (n=29) had a higher blood pressure on admission, as well as a greater body weight, than the women who were normotensive at the follow-up investigation. Forty-six of the 100 re-studied women were taking contraceptive pills. Seven developed hypertension while 'on the pill'. Four of these became normotensive after discontinuating the pill.

Blood Pressure↗
PubMed1977

Per-operative intravascular tumor cell shedding. An experimental methodological study.

A previously reported experimental technique for estimation of the per-operative intravascular tumor cell shedding was further studied. A significant increased tumor cell shedding was found in rats after tumor biopsy compared with animals operatively prepared for such a biopsy. An attempt was made to estimate the number of intravascularly shedded vital tumor cells under biopsy.

Animals↗
PubMed1976

Plasma high-density lipoprotein cholesterol concentrations determined after removal of other lipoproteins by heparin/manganese precipitation or by ultracentrifugation.

The widely used heparin/MnCl2 precipitation procedure for determination of plasma high-density lipoprotein cholesterol has been re-examined in light of recent reports that isolated preparations of the lipoprotein are only partly precipitated under the test conditions. In the present study, the procedure as applied to plasma tolerated rather wide variations in heparin and MnCl2 concentrations without significant effects on the assayed values in several plasma pools tested. The procedure was further tested on 129 individual samples by comparison with an ultracentrifugal method in which high-density lipoprotein-cholesterol is assumed to be represented by the cholesterol content of the plasma fraction of relative (to water) density greater than 1.063. Our results indicate that high-density lipoprotein is not precipitated under the test conditions when applied to unfractionated plasma.

Cholesterol↗
PubMed1972

Nonrandom bioelectrical signals in plant tissue.

The results of investigations on nonevoked bioelectrical activity in the India-rubber tree (Ficus elastica) are presented. Metal electrodes inserted into the plant issue were used as the ionic-to-electronic conduction converting elements. Nonevoked pulse bursts were observed with amplitudes in the 10 to 200 microvolts range. An upper limit value of the cell refractory period has been estimated from the maximum pulse frequency observed.

Journal Article↗