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Biomedical subjects

T Jogestrand

Publications and source records attributed to T Jogestrand.

At least 55 records · Page 3Linked to original sources
PubMed1993

Effect of autonomic blockade on digoxin-induced ECG changes at rest and during exercise in healthy subjects.

The effect of pharmacological autonomic blockade on digoxin-induced electrocardiographic changes at rest and during exercise was studied in nine healthy men. The subjects performed bicycle exercise tests on four occasions after: (1) intravenous injection of sodium chloride, (2) intravenous injection of propranolol and atropine, (3) oral ingestion of digoxin 0.5 mg daily for 2 weeks and intravenous injection of sodium chloride, and (4) oral ingestion of digoxin 0.5 mg daily for 2 weeks and intravenous injection of propranolol and atropine. The ST-T segment was significantly depressed after digoxin plus sodium chloride and digoxin plus propranolol and atropine in comparison with sodium chloride only and propranolol and atropine only. The digoxin-induced ST-T changes after sodium chloride and propranolol-atropine injections were not significantly different. Thus, judging from the results of this study, an effect mediated via the autonomic nervous system is an unlikely explanation of digitalis-induced ST-T changes.

Adult↗
PubMed1993

Pain induces decrease of blood flow in the common carotid arteries in cluster headache attacks.

Eighteen cluster headache patients and five controls were studied using ultrasound duplex techniques to measure blood flow in the common carotid arteries after nitroglycerin and placebo administration. Vessel diameter and blood flow tended to be greater before nitroglycerin in patients in the cluster headache period than in patients out of period and controls. Nitroglycerin tended to increase blood flow only in patients not in the cluster period and in controls. There was a significant decrease in common carotid blood flow and increase in vascular resistance related to maximum pain in both nitroglycerin-induced and spontaneous cluster headache attacks. Blood flow did not reach the initial flow values after the attack was over. In one patient a hyperventilation attack only temporarily decreased the pain. We suggest that the decrease in blood flow and increase in vascular resistance may be due to constriction of intracranial arteries by reflex activation of sympathetic efferents, rather than to decrease of arterial CO2 tension.

Adult↗
PubMed1993

Intracranial hypertension and sumatriptan efficacy in a case of chronic paroxysmal hemicrania which became bilateral. (The mechanism of indomethacin in CPH).

A female patient is described who had a four year long period of unilateral chronic paroxysmal hemicrania (CPH) which then became bilateral. For some years before the CPH started she suffered from periods of about one month with chronic hemicrania without nerve involvement. She also suffered from chronic fatigue, back pain, arthralgia, vertigo, chronic constipation and spontaneous ecchymoses. Blood tests showed chronic leukocytosis, low serum iron, and signs of inflammation in serum electrophoresis during the five years she was studied. CPH attacks could be provoked by breathing 6% carbon dioxide in air. Lumbar cerebrospinal fluid pressure was pathologically increased (30 cm water). The attacks decreased during indomethacin treatment but 275 mg was needed for satisfactory control of the attacks, i.e., more than the 150 mg which, according to the criteria for CPH, should be absolutely effective. Sumatriptan was found to suppress the CPH attacks as well as indomethacin. Due to these findings CPH is considered to be another manifestation of venous vasculitis. The beneficiary mechanism of indomethacin in CPH is considered to be due partly to its anti-inflammatory effects and partly to its reduction of the intracranial blood flow.

Adult↗
PubMed1993

Effects of renal failure on skeletal muscle.

In this cross-sectional study, we examined biopsies from the vastus lateralis muscle of 13 predialytic uremic men (mean age 46 +/- 8 years). Their average glomerular filtration rate was 14 +/- 7 ml/min x 1.73 m2 and their maximal exercise capacity, measured by standardized exercise test on a bicycle ergometer, was 184 +/- 45 W (94% of the expected norm). The proportion of type I fibers (type I%) in the uremic group was similar to that of the reference group (42 +/- 11 vs. 41 +/- 8% NS). The proportion of type IIA fibers (type IIA%) in the uremic group was higher than in the reference group (44 +/- 10 compared to 35 +/- 9%, p < 0.05). The proportion of type IIB fibers (type IIB%) was lower than in the reference group (13 +/- 8 vs. 21 +/- 8%, p < 0.05). Type I fiber area was similar to that of the reference group (4,768 +/- 1,033 vs. 4,627 +/- 1,112 microns 2, NS). Type IIA and type IIB fiber areas tended to be smaller than those of the reference group (type IIA fiber area: 4,515 +/- 929 vs. 5,213 +/- 1,288 microns 2, NS; type IIB fiber area: 3,953 +/- 1,066 vs. 4,406 +/- 1,582 microns 2, NS) with a type IIA area/type I area ratio which was significantly lower than in the reference group. Citrate synthase activity was 0.48 +/- 0.08 mu kat/g in the uremic group and 0.50 +/- 0.08 mu kat/g in the reference group, NS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The effect of digoxin on the serum potassium concentration.

In recent studies on the influence of muscular and symphatoadrenergic activity on digoxin pharmacokinetics, the serum potassium concentration was found to increase during 2 h of supine rest in digitalized healthy subjects and out-patients. The present study was made in order to find out whether this change in serum potassium concentration is dependent on inhibition of the Na-K-ATPase activity by digitalis treatment. Ten healthy subjects were investigated on two separate occasions: before and after digitalization with digoxin 0.37-0.50 mg daily for 10 days. Serum potassium and digoxin concentrations were analysed before and after 2 h of rest in the sitting position. Without digoxin treatment, no change in serum potassium concentration was seen. During digoxin treatment, the serum potassium concentration increased by 0.19 +/- 0.23 mmol(l)-1 (p < 0.05) during the period of rest. Thus, a digitalis-induced depression of Na-K-ATPase activity seems to be a prerequisite for the described change in serum potassium concentration.

Adult↗
PubMed1993

Minimally invasive and non-invasive diagnosis of carotid artery obstructive disease: an evaluation of supraorbital fluorescein angiography and ultrasonic duplex technique.

The carotid arteries of twenty-five patients with transient ischaemic attacks, minor stroke or amaurosis fugax were examined by conventional angiography, the ultrasonic duplex technique and supraorbital fluorescein angiography (SOFA). The results of the last two techniques (non-invasive and minimally invasive, respectively) were compared with the results of angiography. We found that the ultrasonic duplex technique is highly sensitive and specific for both high and low-grade carotid stenoses while the less costly SOFA can only identify stenoses equal to or more than 75%. However, since tight stenosis has proved to be an indication for surgical reconstruction, SOFA - or possibly the still simpler procedure with direct ocular inspection of the supraorbital fluorescence pattern without any recording - would be useful for initial screening in smaller units without access to ultrasonic duplex examination. In this way potential candidates for surgery can be identified without delay and forwarded to larger units for further supplementary examinations.

Adult↗
PubMed1992

Effect of salbutamol on digoxin pharmacokinetics.

A single dose of the beta 2-adrenoceptor agonist salbutamol has previously been shown to decrease serum digoxin concentration in healthy volunteers. A possible explanation of the phenomenon is a beta 2-adrenoceptor-mediated increase in the specific binding of digoxin to skeletal muscle. The present study was undertaken to further elucidate the effect of salbutamol on the pharmacokinetics of digoxin in man. Nine volunteers were studied on two occasions during salbutamol or placebo treatment. On test days salbutamol, 4 micrograms.kg-1.h-1 or saline was infused for 10 h, preceded and followed by four and three days, respectively, of oral administration. A single i.v. injection of digoxin 15 micrograms.kg-1, was given 20 min after starting the infusion. At the end of the infusion a muscle biopsy was taken from the vastus lateralis. Blood samples for the analysis of serum digoxin and potassium were repeatedly taken over 72 h. Urine was collected over a period of 24 h for determination of the renal excretion of digoxin and potassium. The serum digoxin concentration, expressed as the AUC 0-6 h was 15% lower during salbutamol infusion than during saline infusion. Salbutamol caused significantly faster elimination of digoxin from the central volume of distribution to deeper compartments. Salbutamol had no effect on the renal clearance of digoxin. The skeletal muscle digoxin concentration tended to be higher (48%) during salbutamol compared to placebo treatment. The serum potassium concentration was significantly lower after salbutamol compared to placebo, as was the rate of renal excretion of potassium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Platelet activation and prostacyclin release in essential hypertension.

To evaluate platelet activation thromboxane A2 (TxA2) and beta-thromboglobulin (beta TG) were used as markers and in addition we studied the biosynthesis of prostacyclin. Synthesis of TxA2 and prostacyclin was assessed by measurement of urinary metabolites. Fifteen untreated hypertensive patients (HT) and 15 age-matched normotensive controls (NT) were investigated at rest, during and after exercise. HT patients were re-examined after 3 months on enalapril. During basal conditions there was no difference in the excretion of Tx-M, PGI-M or beta TG between the groups. During strenuous exercise HT exhibit a significantly higher increase in prostacyclin synthesis (162%) compared to NT (76%). The levels of beta TG increased with 82% in the HT and 24% in the NT group, Tx-M increased with 27% and 23% respectively. Treatment with the ACE-inhibitor enalapril did not significantly alter these findings. These results indicate that there is no evidence of basal platelet activation in early essential hypertension. Strenuous exercise leads to some increase in Tx-M in both groups, with no pronounced differences between the groups. Hypertensive patients exhibit a significantly increased prostacyclin response to exercise which could be due to differences in vessel-wall reactivity. Enalapril seems to exert no effect on platelet activation or on prostacyclin biosynthesis.

Adult↗
PubMed1992

Non-invasive assessment of vessel-wall changes in hypertensives and normotensive controls.

The aim of this study was to evaluate the feasibility of non-invasive assessment of vessel wall changes in early, untreated hypertension. Measurement of intimal+medial (I-M) thickness in the common carotid artery (CCA) using B-mode ultrasound imaging showed no differences between 12 patients with untreated, newly diagnosed hypertension and 9 age-matched controls (0.63 mm vs 0.63 mm just proximal to the carotid bulb). Echocardiography showed that the hypertensive group had thicker left ventricular walls (LVW) than the normotensive group. Correlation analyses disclosed that I-M thickness was significantly associated with age (r = 0.63; P less than 0.05) for the whole material but not with blood pressure levels, serum lipids, or LVW thickness. These results imply that the arterial I-M layers of the CCA are less responsive to pressure overload than the left ventricle. The feasibility of using I-M thickness as an early marker of structural vessel wall changes in hypertensive patients must await results from large scale prospective studies. In view of the present results, age homogenous materials should be selected for such studies.

Adult↗
PubMed1992

Effect of erythropoietin treatment on physical exercise capacity and on renal function in predialytic uremic patients.

Anemia is already present in patients with moderate renal failure and is a major cause of the decline in exercise capacity seen in these patients. We examined the effects of erythropoietin (EPO) treatment in 12 predialytic uremic patients (EPO group: mean age 46 +/- 12 years; 6 men, 6 women) with a mean glomerular filtration rate (GFR) of 10 +/- 4 ml/min x 1.73 m2. These patients were compared to a control group of 8 patients (5 men, 3 women). The observation period was 3 months. The EPO group received 300 U/kg body weight i.v. once a week. The EPO group increased their total hemoglobin (THb) from 323 +/- 89 to 466 +/- 128 g (p less than 0.001) and their hemoglobin concentration from 86 +/- 8 to 117 +/- 11 milligrams (p less than 0.001). Their exercise capacity, measured by a standardized exercise test on a bicycle ergometer, increased from 128 +/- 45 to 147 +/- 57 W (p less than 0.01). The control group did not change their THb (349 +/- 124 and 357 +/- 131 g), hemoglobin (93 +/- 8 and 94 +/- 10 milligrams) or exercise capacity (98 +/- 49 and 101 +/- 50 W) during the observation period. There was a significant correlation between the increase in THb and the increase in exercise capacity in the EPO group (r = 0.81, p less than 0.005). The GFR was unchanged in both groups (EPO group: 10 +/- 4 and 10 +/- 6 ml/min x 1.73 m2; control group: 8 +/- 3 and 8 +/- 3 ml/min x 1.73 m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effects of adrenaline and mental stress on serum digoxin concentration.

Physical activity and pharmacological stimulation of beta 2-adrenoceptors by salbutamol increase skeletal muscle digoxin binding with a secondary decrease in serum digoxin, possibly due to increased Na-K-ATPase activity. The present study was undertaken to examine if adrenaline (ADR) infusion and sympathoadrenal stimulation by mental stress affect the serum concentrations of digoxin and potassium. After 10 days on 0.50 mg digoxin orally, 35 healthy volunteers were investigated following 2 h of supine rest. They were divided into four groups: intravenous saline (placebo, n = 10). ADR infusion at the rates of 0.1 nmol kg-1 min-1 (ADR-L, n = 8), 0.4 nmol kg-1 min-1 (ADR-H, n = 7), or subjected to a mental stress [a color-word conflict test (CWT), n = 10]. Arterial blood samples were taken before and during the active period (50 min) and during the following 60 min (at rest) to analyze serum digoxin and potassium and plasma ADR and noradrenaline (NA). All variables were stable during placebo infusion. ADR infusions caused significant and dose-dependent decreases in serum digoxin (p less than 0.05 during ADR-L and p less than 0.001 during ADR-H) and serum potassium (p less than 0.05 and p less than 0.001, respectively). CWT, on the other hand, did not reduce serum digoxin and caused a slight decrease in serum potassium only in the poststress period. Thus, ADR caused dose-dependent shifts of digoxin and potassium, whereas mental stress failed to do so, possibly due to a modest ADR response and small increases in sympathetic nerve activity in skeletal muscle.

Administration, Oral↗
PubMed1991

Effects of exercise training in predialytic uremic patients.

We examined the effects of physical training in 10 predialytic uremic patients (7 men, 3 women, mean age 47 +/- 8 years) with an average glomerular filtration (GFR) of 15 +/- 7 ml/min x 1.73 m2. All 10 patients participated in an exercise programme 3 times/week for 3 months and were compared to a control group of 9 patients with comparable baseline variables. The exercise group increased its maximal exercise capacity measured by standardized exercise test on a bicycle ergometer, from an average 159 +/- 49 to 174 +/- 57 W (p less than 0.01). They also showed a decrease in heart rate at equal load (138 +/- 29-123 +/- 18 beats/min, p less than 0.05). The control group did not change its exercise capacity (171 +/- 60 and 171 +/- 65 W, respectively, NS), nor its heart rate at equal load (124 +/- 24 and 123 +/- 24 beats/min, respectively, NS). Thigh muscular function assessed by static endurance increased from a median 77 s (range 27-197) to 113 s (range 66-201), p less than 0.002. Dynamic muscular endurance increased from a median number of 41 movements (range 28-105) to 93 movements (range 45-139), p less than 0.001. The corresponding figures for the controls were: static endurance 60 (range 20-209) and 47 s (range 9-203), respectively, NS; dynamic endurance 53 (range 19-190) and 43 movements (range 10-126), respectively, NS. Total hemoglobin, blood volume, GFR, blood pressure and echocardiographic variables remained unchanged during the observation period. We conclude that in predialytic uremic patients, physical training improves exercise capacity mainly due to an improved muscular function.

Adult↗
PubMed1990

Oral salbutamol decreases serum digoxin concentration.

The effect of a therapeutic dose of oral salbutamol on serum and skeletal muscle digoxin concentrations has been studied in volunteers digitalised with digoxin. On one occasion a biopsy was taken from the quadriceps after 2 h of supine rest and then 3-4 mg salbutamol was given orally. Blood samples were taken before and after that dose and another muscle biopsy specimen was taken from the same thigh 180 min after the medication. On another occasion control blood sampling, ECG and blood pressure recordings were made but without muscle biopsies or salbutamol administration. Compared to the control measurements, salbutamol decreased the serum digoxin concentration (0.30 nmol.l-1). It also reduced the serum potassium concentration (0.58 mmol.l-1). The digoxin concentration in skeletal muscle did not change significantly after the intake of salbutamol. Thus, even a therapeutic oral dose of salbutamol reduces the serum digoxin concentration in man.

Adult↗
PubMed1989

Effect of salbutamol on digoxin concentration in serum and skeletal muscle.

Beta 2-receptor stimulation has been reported to increase the concentration of 3H-ouabain in rat skeletal muscle. The present study was undertaken to see if beta 2-adrenoceptor stimulation by i.v. injection of salbutamol had any influence on the pharmacokinetics of digoxin in man. Ten volunteers were digitalized with digoxin and were investigated on two occasions. On each occasion a muscle biopsy was taken from the quadriceps after 2 h of supine rest. An injection of salbutamol 4 micrograms.kg-1 b.wt. or saline was then given intravenously. Blood samples were taken before and after the injection and further muscle biopsy was taken from the same thigh 120 min after the injection. Compared to the injection of saline, salbutamol caused a decrease in the serum digoxin and potassium concentrations. The change in serum potassium was significantly correlated with that in digoxin. The digoxin concentration in skeletal muscle was not significantly changed by either the salbutamol or saline injections.

Adult↗
PubMed1989

Clinical value of serum digoxin assays in outpatients: improvement by the standardization of blood sampling.

Everyday physical activity previously has been shown to affect serum digoxin concentrations. Standardized rest in the supine position increases outpatient serum digoxin levels 0% to 75%. The present study comprising 56 outpatients treated with digoxin was undertaken to elucidate the clinical importance of a standardized period of rest before collection of the blood sample. Blood samples were taken about 24 hours after the latest dose, before and after 2 hours of rest in the supine position. A careful clinical examination, including electrocardiogram (ECG) findings, systolic time intervals, and chest x-ray studies, was performed to identify adverse effects/intoxication or failure of digitalis treatment. Signs of failure of digitalis treatment occurred in 12% of the patients, with a serum digoxin concentration of 0.68 +/- 0.15 (mean +/- SD) nmol/L before rest and 0.85 +/- 0.22 nmol/L after rest. Eleven percent showed signs of adverse effects/intoxication, with serum digoxin concentrations of 1.70 +/- 0.70 nmol/L before rest and 2.08 +/- 0.80 nmol/L after rest. The serum digoxin concentrations of the adequately treated patients (77%) were 1.02 +/- 0.35 nmol/L before rest and 1.28 +/- 0.41 nmol/L after rest. The importance of standardized rest before blood sampling is illustrated by the fact that only one third of the patients without signs of adverse effects/intoxication or failure of digitalis treatment had serum digoxin concentrations within the therapeutic range most commonly used (1.2 to 2.6 nmol/L) without supine rest. If allowed to rest in the supine position before blood sampling, approximately 60% of the adequately treated patients had serum digoxin concentrations within this range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effect of physical exercise on the pharmacokinetics of digoxin during maintenance treatment.

Blood samples were taken repeatedly and urine was collected for digoxin assays on two occasions from 12 healthy male volunteers after an oral maintenance dose of digoxin. On one occasion the subjects exercised intermittently on a bicycle ergometer for 8 h after the dose. On the other occasion they rested in the supine position during the study period. Thirty and 45 min after the intake of digoxin, the serum digoxin concentration was significantly higher during exercise compared with rest, indicating increased absorption rate during exercise. Two and 4 h after the intake of digoxin, the serum digoxin concentration was significantly lower during exercise than during rest. Furthermore, the intermittent bicycle exercise decreased the renal excretion of digoxin during the study period. It also increased the steady state digoxin concentration measured after a terminating standardized period of rest. The most probable reason for these changes in the pharmacokinetics is a previously described increased binding of digoxin to exercising muscles. According to the results, there is reason to believe that the daily physical activity performed by digoxin-treated patients will determine to some extent the body content of digoxin. Changes in activity from day to day may therefore cause variations in the effect of the drug.

Adult↗
PubMed1989

Factors influencing physical working capacity in renal transplant patients.

Clyne N, Jogestrand T, Lins L-E & Pehrsson SK. Division of Nephrology and Cardiology, Department of Medicine and Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden. We have examined uraemic patients' exercise capacity, and the factors influencing this capacity, before and after successful renal transplantation. Eleven uraemic patients (mean age 41 +/- 10 years) with an average glomerular filtration rate (GFR) of 5 +/- 4 ml/min x 1.73 before and 45 +/- 19 ml/min x 1.73 after transplantation participated in the study. The maximal exercise capacity, measured by standardized exercise test on a bicycle ergometer, averaged 106 +/- 25 W before and 126 +/- 35 W (p less than 0.05) after transplantation. The patients interrupted the tests prior to and after transplantation because of general fatigue, leg tiredness or both. No patient experienced angina pectoris. All, but one, had a normal ECG reaction during exercise. Total haemoglobin (THb) was 55 +/- 8% of the expected normal before and 84 +/- 19% after transplantation (p less than 0.01). The increase in working capacity was linearly correlated to the increase in THb (r = 0.84, p less than 0.01), but not to the improvement in GFR nor to the decrease in parathyroid hormone. In conclusion, successful renal transplantation improves working capacity. The results indicate that an increased THb is a major determinant for this increase in working capacity.

Adult↗