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Biomedical subjects

B Persson

Publications and source records attributed to B Persson.

At least 523 records · Page 29Linked to original sources
PubMed1980

Pre- and postsynaptic alpha-adrenoceptor antagonists: differentiated cardiovascular effects in the rat.

Intravenous (i.v.) injections of yohimbine, phentolamine, prazosine and phenoxybenzamine lowered blood pressure and increased heart rate in conscious rats. Intracerebroventricular (i.c.v.) injections of yohimbine and phentolamine increased blood pressure and heart rate; this was antogonized by pretreatment with clonidine. Phenoxybenzamine and prozosine had no effect or gave hypotension and tachycardia on i.c.v. injection. Pentobarbitone anaesthesia partly antagonized the cardiovascular effects of all alpha-adrenoceptor antagonist. Synthesis and utilization of central noradrenaline was increased by i.v. or i.c.v. yohimbine; anaesthesia partly antagonized this effect. In peripheral tissues others have found that yohimbine, tolazoline, piperoxan and phentolamine are potent blockers of the presynaptic alpha-adrenoceptors while phenoxybenzamine and prazosine act preferentially on postsynaptic alpha-adrenoceptors. The differentiated cardiovascular response to i.c.v. injection of these blockers may reflect their different affinity to central pre- and postsynaptic alpha-adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed1980

[Comparison of Micro-ID, API 20 E and a conventional technique for the identification of Enterobacteriaceae].

A new system, Micro-ID, for the identification of Enterobacteriaceae is described. 100 strains of Enterobacteriaceae (Table I) are identified by Micro-ID and the identifications are compared with the identifications performed by conventional techniques and by the API 20 E system. There is a total agreement between Micro-ID and conventional techniques on 96.5% and between API 20 E and conventional techniques on 90% (Tables II and III). The differences in the reactions between the systems are discussed and explained. It is concluded, that the Micro-ID and the API 20 E both are very suitable for the identification of Enterobacteriaceae.

Bacteriological Techniques↗
PubMed1980

Effects of catecholamines on cardiovascular response and blood flow distribution to normal tissue and liver tumors in rats.

The effects of infusion of adrenaline and noradrenaline were studied in rats with intrahepatic tumors, using 99mTc-and 51Cr-labeled microspheres. The effect on general circulation, cardiac output, and tissue blood flow was pronounced, especially with infusion of noradrenaline. Studies of liver tumor perfusion in relation to surrounding liver parenchyma perfusion showed an increased tumor/liver ratio in noradrenaline-infused rats, thus indicating a preferential blood flow to the tumors induced by this drug. Adrenaline as well as 0.9% NaCl solution infusion had no effect on tumor/liver blood flow ratios. Fluorescence microscopy and monoamine determination could not reveal any noradrenaline containing nerves in the liver tumors. These experiments might suggest that the effect of intraarterial infusion with cytostatic agents might be enhanced by a simultaneously administered vasoconstrictor such as noradrenaline.

Animals↗
PubMed1980

Blood flow in experimental liver tumors: effect of vasoactive drugs.

The effects of infused glucagon, histamine and vasopressin on blood flow in anaesthetized rats with intrahepatic tumors were studied using microspheres labelled with 99Tcm or 51Cr isotopes. Considerable circulatory effects were noted both in central hemodynamic parameters as well as in organ and tissue blood flows. glucagon infusion increased blood flow in the spleen and small intestine while hepatic artery flow was unchanged. Histamine induce a decrease in hepatic and pulmonary blood flow Vasopressin showed a pronounced decrease in blood flow in all organs measured. Relative tumor blood flow was registered as the ratio between tumor flow and arterial hepatic flow. A relative decrease of tumor blood flow in relation to surrounding liver tissue blood flow was registered after infusion of vasopressin. No effects were seen after glucagon or histamine infusion.

Adenocarcinoma↗
PubMed1979

Total cortisol and L/S-ratio in amniotic fluid in late pregnancies complicated by diabetes mellitus.

68 samples of amniotic fluid from 47 women with varying severity of diabetes mellitus and 48 samples from 43 normal women were obtained in the 31st to 40th week of pregnancy before onset of labour. The concentration of total cortisol and the L/S-ratio in amniotic flud were determined and related to gestational age. There was a continous rise of total cortisol with advancing gestational age in the diabetic pregnancies similar to that found in normal pregnancy. Diabetic pregnancies were associated with slightly lower amniotic fluid cortisol levels without significant difference to values found in normal pregnancy. The severity of the disease did not affect the cortisol levels in amniotic fluid. There was no correlation between total cortisol levels and L/S-ratios in amniotic fluid. Determination of total cortisol in amniotic fluid can thus not replace measurements of L/S-ratios to predict fetal lung maturation.

Amniotic Fluid↗
PubMed1979

Ketotic hypoglycemia of childhood--a clinical trial of several unifying etiological hypotheses.

We have studied 15 children referred to St. Göran's Children's Hospital because of suspected ketotic hypoglycemia. The patients were investigated according to a program designed to test several hypotheses--old and new--postulated to explain the etiology of ketotic hypoglycemia. We have used the classical ketogenic provocation with a low calorie, high fat diet and measured the blood levels of several substrates and hormones as well as the urinary excretion of certain metabolites and hormones. Out of the 15 children, 6 will fill the criteria of ketotic hypoglycemia at the time of study. The most remarkable finding in these 6 children in contrast to the other children studied was that they did not decrease their peripheral glucose utilization (measured as Kg) during starvation. These 6 children seemed to be more "advanced" in their adaptation to ketogenic diet in all other parameters studied. The children with ketotic hypoglycemia did not differ from the other children in plasma level of cortisol or urinary excretion of nitrogen, urea, 3-methylstidine and catecholamines. We favour the concept that the children with ketotic hypoglycemia represent the tail of the gaussian curve in the normal age-dependent development of the adaptation to starvation.

Alanine↗
PubMed1979

Measurements of cardiac output and organ blood flow in rats using 99Tcm labelled microspheres.

The cardiac output and regional blood flow have been simultaneously determined in the anesthetized rat by using the reference organ method. 99Tcm labelled dextran 15 micron microspheres were injected in the left ventricle while simultaneously an arterial reference sample was drawn at constant known rate. The values calculated regarding cardiac output agree well with previously recorded series. Regional organ blood flow in the rat is presented as ml . min-1 . g-1 tissue and values do agree with those reported by others. The results indicate that the reference organ method can be used in the rat for the study of cardiac output and regional blood flow.

Animals↗
PubMed1979

Acute metabolic and circulatory effects of cigarette smoking in late pregnancy.

The acute metabolic and circulatory effects of cigarette smoking (two cigarettes of a standard brand) in the last trimester of pregnancy were studied. 12 subjects, all of whom where hospitalized because of pregnancy complications, volunteered to participate in the investigation. A statistically significant immediate increment in the maternal heart rate, systolic and diastolic blood pressure, fetal heart rate, plasma glucose and plasma cyclic AMP was noted. Plasma glycerol, plasma insulin and blood lactate did not change significantly. 30 min after smoking there was a small but significant increase in plasma nonesterified fatty acids, plasma beta-hydroxybutyrate and plasma C-peptide.

Blood Glucose↗
PubMed1979

Biological fate of methenamine in man. Absorption, renal excretion and passage to umbilical cord blood, amniotic fluid and breast milk.

Methenamine hippurate was administered orally as tablets or granules to healthy volunteers. Plasma concentrations of methenamine reached a maximum 1--2 hours after a single dose and then declined with a half-life of about 4 hours. The apparent distribution volume was similar to that of total body water. Renal clearance of methenamine was somewhat lower than that of creatinine. In cross-over experiments over six days, methenamine recovered in the urine corresponded to about 80 per cent of the dose given per 12 hours, slightly lower values being obtained from granules than from tablets. The efficient renal elimination of methenamine was confirmed in similar studies on patients post-operatively. Methenamine hippurate was also given to healthy pregnant women during labor, a few hours before expected delivery. Methenamine was found to pass the placental barrier. The concentration of methenamine in umbilical cord plasma was low but reached the level in maternal plasma after about 4 hours. In amniotic fluid the methenamine con centration was low and varying. No correlation was obtained to the maternal or umbilical cord plasma levels. The methenamine concentration in breast milk was of the same magnitude as in maternal plasma. It is concluded that methenamine may be safely given to pregnant and lactating women with respect to the ellbeing of the child.

Absorption↗
PubMed1979

Circulatory and metabolic effects of acute beta 1-blockade in severe pre-eclampsia.

Five mg of a beta 1-adrenoceptor antagonist (atenolol) was given i.v. to 5 women with severe pre-eclampsia in the 3rd trimester of pregnancy. There was a significant decrease of both mean systolic blood pressure, from 171 to 155 mm Hg, and mean diastolic blood pressure, from 116 to 107 mm Hg. The mean maternal heart rate decreased significantly from 90 to 74 and mean fetal heart rate significantly from 145 to 138 beats per min. There were no significant changes in the plasma levels of cyclic AMP, insulin, glucose, free fatty acids, 3-hydroxy-butyrate or glycerol.

Adolescent↗
PubMed1978

An inhibitor from placenta specifically binds urokinase and inhibits plasminogen activator released from ovarian carcinoma in tissue culture.

An inhibitor present in placenta and released in placental tissue culture forms specific complexes with each of two molecular forms of urokinase. Autoradiography demonstrated that the inhibitor shifted the electrophoretic position of 125I-labelled urokinase. It did not change the migration of diisopropyl-fluorophosphate-inactivated 125I-labelled urokinase, thereby indicating complex formation dependent on active serine site in urokinase. The inhibitor had a strong neutralizing effect on the plasminogen activators released from human ovarian carcinoma in tissue culture. The placental inhibitor might prove useful in inhibiting the fibrinolytic process necessary for proliferation of tumour vessels.

Endopeptidases↗