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Biomedical subjects

B Persson

Publications and source records attributed to B Persson.

At least 415 records · Page 23Linked to original sources
PubMed1985

Computer controlled microwave system for clinical hyperthermia.

A hyperthermia system which has been developed for clinical use is described. Different direct-contact applicators working at the ISM microwave frequency of 915 MHz are used for inducing heat in superficial tumours to a depth of about 3 cm. The system is a further development of an earlier prototype which worked at 2450 MHz. The microwave generator is controlled by a microcomputer governed by temperature measurements with thermistor probes inserted into the tissue. To minimise the influence of the interaction between the microwaves and the temperature probes, a pulsed irradiation technique is used. Up to July 1984, 80 superficial tumours had been treated with radiotherapy combined with local hyperthermia applied using this system.

Computers↗
PubMed1985

Antihypertensive effects of ketanserin in the spontaneously hypertensive rat: mode of action.

In the spontaneously hypertensive rat (SHR), ketanserin and the ketanserin analogues R56413 and ritanserin were studied with regard to their ability to reduce the blood pressure in conscious rats and shift the dose-response curves for phenylephrine and serotonin (5-HT) in pithed rats after acute administration. There was a striking correlation between the degree of hypotension and the degree of inhibition of the phenylephrine-induced pressor responses. 5-HT2-receptor blockade alone by ritanserin did not influence the blood pressure but it potentiated the hypotensive response to alpha 1-adrenoceptor blockade by prazosin. Thus, following acute administration in the SHR, the major portion of the antihypertensive response to ketanserin is due to an alpha 1-adrenoceptor blockade but the 5-HT2-receptor blockade may contribute.

Animals↗
PubMed1985

Chronic serotonergic blockade with ketanserin in the spontaneously hypertensive rat.

Spontaneously hypertensive rats were fed ketanserin-enriched (17 mg/100 g) or control chow for 6 weeks. After 6 weeks the blood pressure was reduced (16%). Pressor responses to phenylephrine were not different from control responses, which indicates that at this time the antihypertensive effect was not directly related to an alpha-adrenoceptor blockade. Cardiovascular responses to stress (jet air), baroreceptor sensitivity (bradycardia to phenylephrine), and central catecholamine turnover were unchanged, which supported the view that central mechanisms probably do not contribute to the antihypertensive effects of ketanserin.

Animals↗
PubMed1985

A comparative and long-term evaluation of ketanserin in the treatment of essential hypertension.

Ketanserin is a serotonin (S2) blocker that reduces blood pressure (BP) in patients with essential hypertension preferentially by a reduction of peripheral vascular resistance. Heart rate is generally not affected or slightly reduced. When given in monotherapy on a 40 mg b.i.d. regimen, ketanserin reduces diastolic BP as effectively as metoprolol 100 mg b.i.d. or hydrochlorotiazide 25 mg b.i.d. The incidence of adverse reactions is low and comparable to these reference drugs. A satisfactory BP control is provided over a 24-h interval on a 40 mg b.i.d. dosage schedule, and the effect is maintained on a long-term basis, i.e., greater than 2 years. The response seems to be more marked in older patients, which may be due to an augmented platelet serotonin release and a vascular hypersensitivity in this age group. The future usefulness of ketanserin, as well as any other antihypertensive agent, will depend on its ability to prevent organ damage, as well as its ability to provide "quality of life" for the patient.

Adrenergic beta-Antagonists↗
PubMed1985

Antihypertensive properties of ketanserin in combination with beta-adrenergic blocking agents.

The antihypertensive effect of ketanserin in combination with beta-adrenergic blockade was assessed in a double-blind crossover (4 weeks) manner in 10 patients with essential hypertension. The addition of ketanserin (40 mg b.i.d.) to optimal doses of beta-adrenergic blockers had significant antihypertensive effects compared with treatment with beta-adrenergic blockers alone. When followed for 24 h at steady-state conditions, ketanserin effectively reduced the blood pressure during a major part of the day, with maximal effect occurring at the time of the peak plasma concentration of ketanserin (1-2 h after tablet intake). Six patients initially reported a slight sedation during ketanserin treatment.

Adrenergic beta-Antagonists↗
PubMed1985

Chronic salt loading and central adrenergic mechanisms in the spontaneously hypertensive rat.

The effects of chronic salt loading on central adrenergic mechanisms were evaluated in spontaneously hypertensive rats maintained on tap water or 1.2% sodium chloride drinking water for 4 weeks. Basal blood pressure was increased by 10% in the high salt group. Central catecholamines were measured spectrofluorimetrically after cation exchange chromatography. Endogenous levels of noradrenaline (NA) were not influenced by salt loading but the NA turnover (disappearance of NA following synthesis inhibition by alpha-methyltyrosine) was increased in the hemisperes. Central alpha 2-adrenoceptor sensitivity was assessed as the clonidine-induced reduction in blood pressure and as the clonidine-induced deceleration of NA turnover and locus coeruleus (LC) NA cell firing rate (single unit recording). The results were slightly disparate but the unchanged sensitivity of clonidine to reduce LC NA cell firing suggests that there were no alterations in central alpha 2-adrenoceptor sensitivity following a salt load. There were also no changes in alpha 1-adrenoceptor function, which was assessed semiquantitatively as the clonidine-induced increase in flexor reflex activity in spinalized rats. In salt loaded rats there was an enhanced blood pressure and heart rate reduction following ganglionic blockade which may be interpreted as an increased basal sympathetic tone. In the periphery the pressor responses to phenylephrine were increased whereas the chronotropic response to isoprenaline was unchanged. In conclusion, in the spontaneously hypertensive rat on a high salt intake the aggravated development of hypertension was not associated with major changes in central alpha 1 and alpha 2-adrenoceptor mediated functions or in neuronal activity of brain stem NA neurons. There were indications of an increased basal sympathetic tone and increased blood pressure response to pressor substances.

Animals↗
PubMed1985

Cardiovascular effects in the Sprague-Dawley rat of 8-hydroxy-2(di-N-propylamino) tetralin, a selective 5-hydroxytryptamine receptor agonist.

The intravenous administration of 8-hydroxy-2(di-N-propylamino) tetralin, a selective 5-HT receptor agonist, caused a biphasic blood pressure response and bradycardia in Sprague-Dawley rats. The initial pressor response involved peripheral alpha 1-adrenoceptors since it was present in pithed rats and was antagonized by prazosin. Though the intracerebroventricular route of administration was not more effective the hypotension and bradycardia were probably of central origin. The bradycardia was prevented by pretreatment with atropine and propranolol suggesting an involvement of vagal as well as sympathetic activity. These results support the view that central 5-HT receptor activation reduces the blood pressure and heart rate.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1985

Visualisation of stereotactic radiolesions by nuclear magnetic resonance.

The ability to visualise stereotactic brain lesions produced by irradiation from the stereotactic Gamma Unit at the Karolinska Hospital was investigated. A patient who had undergone bilateral stereotactic gamma capsulotomy in two stages was examined by the nuclear magnetic resonance imaging technique, which demonstrated that the stereotactic lesions in the internal capsule could be visualised in the immediate postoperative period. This gives stereotactic radiosurgery a reliable anatomical basis and facilitates the planning and follow-up studies in this type of cerebral surgery.

Adult↗
PubMed1985

Surveillance of the diabetic pregnancy with antepartum fetal nonstress testing and urinary estriol excretion.

The value of daily fetal heart rate (FHR) nonstress test (NST) and 24-hour urinary excretion of estriol (E3) were compared in a consecutive series of 76 diabetic pregnancies. The NST scoring system (0-10 points) employed included monitoring of fetal movements in addition to evaluation of FHR decelerations, accelerations as well as frequency and amplitude of oscillations. Patients were delivered electively after 38 weeks of gestation unless spontaneous labor began earlier or if delivery was indicated for either maternal reasons or presumed fetal distress. Fetal distress was believed to be present if two consecutive NST scores were 6 points or less. Seven patients had a day-to-day E3 fall of 50% or more at least once. Six of these patients had normal NST scores and 5 of the infants showed no signs of asphyxia at delivery. Forty-two patients had E3 drops of 30-50% and 27 patients had E3 drops of less than 30%; in contrast, the NST scores were 6 or less in 15 patients but were normal the next day. These data indicate that measurements of urinary excretion of E3 give many false alarms of fetal jeopardy and that daily NST can replace measurement of urinary excretion of E3 and reduce unwarranted intervention and unnecessary prematurity.

Estriol↗
PubMed1985

Gestational diabetes mellitus (GDM). Comparative evaluation of two treatment regimens, diet versus insulin and diet.

Two-hundred and two pregnant women with impaired glucose tolerance were randomized to treatment with diet or diet and insulin by stratified selection. Self-monitoring of blood glucose was performed six times a day, 3 days/wk. Dietary treatment was considered inappropriate if fasting and postprandial blood glucose values exceeded 7 and 9 mmol/L, respectively, in which case insulin therapy was instituted. Insulin doses were adjusted according to blood glucose values, aiming at fasting and postprandial values below 5 and 6.5 mmol/L, respectively. There were no perinatal deaths. The two treatment regimens disclosed no differences regarding achieved degree of maternal blood glucose control, hemoglobin A1c at delivery, obstetric or neonatal complications, infant's size at birth including skin-fold thickness, or C-peptide concentration in cord serum. Routine treatment of pregnant women with mild carbohydrate intolerance with insulin seems unnecessary. However, 15 patients (14%) in the diet group needed insulin to achieve acceptable blood glucose control, underlining the importance of monitoring blood glucose to detect those who are at risk of developing overt diabetes.

Adolescent↗
PubMed1985

Fluid homeostasis and haemodynamics during sodium restriction in hypertensive men.

To investigate the antihypertensive effect of moderate sodium restriction, the sodium intake of 11 male outpatients was reduced by 120 mmol/day for 4-6 weeks. These patients and an untreated control group were slightly obese and had mild untreated hypertension (WHO 1-2). All subjects were examined before and at the end of the experiment. Diastolic blood pressure fell significantly in the diet group in comparison with the control group. Invasive haemodynamic examinations in the diet group showed an unchanged mean cardiac output and a reduction of mean total peripheral resistance. Plasma volume (Evan's Blue) did not change, neither did extracellular volume as calculated from determinations of tritiated water, total body potassium and body mass. During sodium restriction, plasma renin activity and urinary aldosterone excretion significantly increased. Noradrenaline and dopamine excretion in urine showed no significant changes during sodium restriction, neither did the plasma concentrations of atrial natriuretic peptides. The reduction in mean arterial blood pressure was correlated significantly with a decrease in 24-h sodium excretion and an increase in urinary aldosterone excretion. In conclusion, moderate dietary sodium restriction seems to lower blood pressure by diminishing the total peripheral resistance while cardiac output, extracellular and intravascular volumes are maintained.

Body Fluids↗
PubMed1985

Random capillary blood glucose and conventional selection criteria for glucose tolerance testing during pregnancy.

The normal variation of random capillary blood glucose values and the usefulness of elevated (greater than or equal to 6.5 mmol/l) blood glucose values as a selection criterion for oral glucose tolerance testing (OGTT) during pregnancy were investigated. A consecutive series of 1,500 pregnant women without signs or symptoms of diabetes and 81 pregnant women with conventional selection criteria for OGTT were studied. The mean blood glucose value was 4.66 mmol/l and the 95% tolerance interval of all blood glucose values was 2.93-6.38 mmol/l. Blood glucose levels were not influenced by time of day or trimester of pregnancy. A blood glucose value of 6.5 mmol/l or higher was found in 174 women, 10 of whom had an abnormal OGTT. Four of thirty women with glycosuria or signs of accelerated fetal growth and 7 of 81 women with conventional selection criteria had abnormal OGTT's. The incidence of carbohydrate intolerance during pregnancy was 1.3%. The results of this study suggest that an elevated (greater than or equal to 6.5 mmol/l) random capillary blood glucose value may be a good selection criterion for OGTT in addition to conventional selection criteria when screening for carbohydrate intolerance during pregnancy.

Adult↗
PubMed1984

Self-monitoring of blood glucose by diabetic women during the third trimester of pregnancy.

The clinical value of self-monitoring blood glucose in diabetic pregnancy at home was compared with hospital care in the thirty-second to thirty-sixth week of pregnancy in a prospective randomized study including 100 pregnancies in 97 patients (White's class B, 38; C, 25; D, 28; and F, 9) of which 54 were in the home group and 46 in the hospital group. The duration of pregnancy was not significantly different in two treatment groups, with a median duration of 266.0 days in the home group and 266.5 days in the hospital group. The mean blood glucose values during the study period were 5.9 mmol/L in the home group and 6.0 mmol/L in the hospital group, thus there were no significant group differences. There were no significant group differences in pregnancy complications; however, 10 of 54 (19%) had to interrupt home-monitoring because of pregnancy complications. The perinatal morbidity was not significantly different in the two treatment groups, with the following percentages of complications in the combined series: 4% idiopathic respiratory distress syndrome, 7% transient tachypnea, 2% symptomatic hypoglycemia, 16% hyperbilirubinemia, 22% feeding problems, and 10% erythrocytosis.

Blood Glucose↗
PubMed1984

Adenosine mechanisms in the regulation of breathing in the rat.

The central respiratory effects of various adenosine (A) analogues were studied in halothane-anesthetized rats. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) injections of the A analogues (2-Cla, L-PIA, CHA and NECA) reduced minute ventilation (VE) due to decreases in respiratory frequency (f) as well as tidal volume (VT). Dose-dependent effects were seen after i.c.v. L-PIA in both normal and vagotomized rats. Analysis of the A-induced changes using the occluded breath technique revealed an increase in expiratory time (TE) as well as a decrease in inspiratory drive. NECA, a relatively specific A2 agonist seemed to be somewhat more potent in eliciting respiratory depression than a relatively specific A1 agonist like L-PIA. Pretreatment with the methylxanthine theophylline completely antagonized the respiratory depression induced by L-PIA. It is concluded that central A receptors are involved in the central regulation of breathing and that A interacts with the respiratory control system mainly by decreasing inspiratory neural drive and prolonging expiratory time.

Adenosine↗
PubMed1984

Energy-linked nicotinamide nucleotide transhydrogenase. Properties of proton-translocating mitochondrial transhydrogenase from beef heart purified by fast protein liquid chromatography.

Mitochondrial nicotinamide nucleotide transhydrogenase from beef heart was purified by a novel procedure involving fast protein liquid chromatography and characterized with respect to molecular and catalytic properties. The method is reproducible, gives highly pure transhydrogenase as judged by silver staining, and can be modified to produce large amounts of pure transhydrogenase protein suitable for e.g. sequencing and other protein chemical studies. Transhydrogenase purified by fast protein liquid chromatography is reconstitutively active and pumps protons as indicated by an extensive quenching of 9-aminoacridine fluorescence. Under conditions which generate a proton gradient in the absence of a membrane potential the activity of reconstituted transhydrogenase is close to zero indicating a complete and proper incorporation in the membrane and a preferential regulation of the enzyme by a proton gradient rather than a membrane potential. Treatment of reconstituted transhydrogenase with N,N-dicyclohexylcarbodiimide results in an inhibition of proton pump activity without an effect on uncoupled catalytic activity, suggesting that proton translocation and catalytic activities are not obligatory linked or that this agent separates proton pumping from the catalytic activity.

Aminacrine↗
PubMed1984

Detection by monoclonal antibody of carbohydrate antigen CA 50 in serum of patients with carcinoma.

A solid phase radioimmunoassay was devised for measuring the value of the carcinoma associated carbohydrate antigen CA 50 in serum based on the use of a specific monoclonal antibody (C 50). Samples of serum from 259 patients with carcinoma, 114 patients with other malignancies or inflammatory diseases, and 150 healthy controls were examined. Serum values of CA 50 exceeding the mean plus three standard deviations for control samples from blood donors were found in a high proportion of patients with colorectal adenocarcinomas (50% of those with early, localised tumours and 75% of advanced cases), other gastrointestinal carcinomas (69%), uterine cancer (75% of those with corporeal and 88% of those with cervical cancer), prostatic cancer (90%), lung cancer (52%), and breast, ovarian, kidney, and urinary bladder carcinoma (26-67%). The CA 50 values in samples from patients with inflammatory diseases, including ulcerative colitis, with rare exceptions (0-7%) were within the normal range, as were those in patients with various sarcomas and malignant melanoma. Measuring serum values of CA 50, which is evidently a generalised carcinoma associated antigen, may be useful in clinical research studies of the diagnosis, management, and prognosis of patients with different types of carcinoma.

Aged↗