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Biomedical subjects

A R Andersen

Publications and source records attributed to A R Andersen.

At least 55 records · Page 3Linked to original sources

Symptoms of classic migraine attacks: modifications brought about by metoprolol.

There is little information available concerning whether, and to what extent, migraine-prophylactic agents interfere with the symptoms of migraine attacks. The present study is a placebo-controlled, double-blind study concerning metoprolol in classic migraine. The data refer to the symptoms of single migraine attacks. During metoprolol treatment more attacks were characterized as mild (p = 0.002), and mean global rating (an integrated estimate of headache intensity and of other discomfort) was lower (4.2 versus 5.2, p = 0.003). The mean headache intensity per attack (1.97 versus 2.15) and the mean duration (5.5 versus 6.8 h) were not significantly different. Consumption of analgesics per attack was lower during metoprolol treatment (0.6 versus 1.1; p = 0.02). Attacks with associated symptoms accompanying the headache were fewer during metoprolol treatment (p = 0.014). Total visual and non-visual aura symptoms occurred with similar frequency, but scintillations and paraesthesia were more frequent during metoprolol treatment, whereas speech disturbances were less frequent. In spite of lower consumption of analgesics, the symptoms appeared milder during metoprolol than during placebo. The pattern of changes indicates that metoprolol exerts its action via the sympathetic nervous system; peripheral vasoconstriction is hardly the underlying mechanism of action.

Adolescent↗

Danish very-low-dose aspirin after carotid endarterectomy trial.

The effect of very-low-dose aspirin as an antithrombotic agent was evaluated blindly in 301 patients who had recently undergone carotid endarterectomy. After randomization, 150 patients received aspirin and 151 received placebo. The two groups were comparable with regard to age, sex, blood pressure, previous cerebrovascular events, and smoking habits. The effect of the study medication on platelet aggregation was measured twice in each patient during the first 2 months and at each follow-up visit; the dose was individually adjusted. In 76% of the patients receiving aspirin, 50 mg/day gave satisfactory platelet inhibition, 13% needed 60 mg/day, 8% needed 70 mg/day, and 3% needed 100 mg/day. Platelet aggregation was found to be inhibited in only 1.2% of the measurements in the patients receiving placebo. Observation during treatment averaged 21 months; total intention-to-treat follow-up averaged 25 months. For the combined outcome events of transient ischemic attack, stroke, acute myocardial infarction, and vascular death, aspirin reduced risk by 11% (95% confidence limits: -38% to 48%, p greater than 0.1). Thus, there was no significant effect of very-low-dose aspirin in our trial.

Aspirin↗

Parental perception and management of school-age children's fevers.

Fever is a major childhood complaint. Parents have numerous means at their disposal to assess and manage childhood fevers. Previous studies of parents of infants and preschoolers have uncovered parental fears and misconceptions surrounding fever ("fever phobia"). A study of 84 parents of otherwise well school-age children revealed that these misconceptions remain, regardless of the child's age or parental level of education. The nurse practitioner must understand both parental fears and the body-temperature dynamics of children to successfully access and manage fever in the school-age child.

Adolescent↗

Role of angiotensin in autoregulation of cerebral blood flow.

The presence of the renin-angiotensin system (RAS) in extrarenal tissues, namely the vascular wall and brain tissue, is well established. The availability of effective blocking agents, converting-enzyme inhibitors, has made it possible to further elucidate important functions of the extrarenal RAS. We have found that the angiotensin converting-enzyme inhibitor captopril shifts the limits of cerebral blood flow autoregulation to lower blood pressure levels in normotensive and in spontaneously hypertensive rats. This effect may explain our finding of a remarkable preservation of cerebral blood flow, despite significant blood pressure reduction, in patients with chronic heart failure. We suggest that the effect of angiotensin converting-enzyme inhibition on autoregulation of cerebral blood flow is mediated by a dilatation of larger cerebral arteries, which results from inhibition of the vascular tone normally maintained by locally produced angiotensin II.

Angiotensin II↗

Effect of antihypertensive treatment on kidney function in diabetic nephropathy.

The effect of long term, aggressive antihypertensive treatment on kidney function in diabetic nephropathy was studied prospectively in 11 insulin dependent diabetics (mean age 30). During the mean pretreatment period of 32 (range 23-66) months the glomerular filtration rate decreased significantly and albuminuria and the arterial blood pressure increased significantly. During the 72 (range 32-91) month period of antihypertensive treatment the average arterial blood pressure fell from 143/96 mm Hg to 129/84 mm Hg and albuminuria decreased from 1038 micrograms/min to 504 micrograms/min. The rate of decline in the glomerular filtration rate decreased from 0.89 (range 0.44-1.46) ml/min/month before treatment to 0.22 (range 0.01-0.40) ml/min/month during treatment. The rate of decline in the glomerular filtration rate was significantly smaller during the second three years compared with the first three years in patients who received long term antihypertensive treatment (greater than or equal to 6 years). One patient died from acute myocardial infarction (glomerular filtration rate 46 ml/min/1.74 m2). Effective antihypertensive treatment postpones renal insufficiency in diabetic nephropathy.

Adult↗

Classic migraine: effective prophylaxis with metoprolol.

Metoprolol slow-release tablets (Durules), 200 mg, given once daily in the morning were compared with placebo in the prophylaxis of classic migraine. The trial comprised eight Scandinavian neurologic centres and was designed as a double-blind cross-over study with 4 weeks' run-in, four weeks washout, and 8 weeks of either treatment. Seventy-seven patients with two to eight migraine attacks per month were entered in the trial, and 73 completed it. A total of 1119 attacks with aura symptoms and 374 without were recorded. Metoprolol was significantly better than placebo with regard to the total frequency of attacks (1.8 versus 2.5 attacks/4 weeks), mean duration of attacks (6.0 versus 8.0 h/attack), mean global rating, and consumption of analgesics per attack. Similar differences could be shown for attacks with aura symptoms alone, except for the duration of attacks. Metoprolol is the first drug for which a prophylactic effect in classic migraine has been convincingly demonstrated.

Adolescent↗

Multi-centre versus single-centre trials in migraine.

Migraine trials often have to be performed at many centres, which creates a number of methodological problems. The present paper discusses single-centre versus multi-centre designs and also comments on the design of multiple-independent trials (MIT). From a methodological standpoint, the single-centre design should virtually always be preferred. When it is impossible to recruit enough patients in a single centre within reasonable time, a multi-centre design has to be used. The major advantage of multi-centre trials, apart from recruitment, is that they may yield a more representative basis for conclusions regarding the whole population. Multiple-independent trials give an opportunity to summarize information from different sources. It has not the same methodological strength as the single- or multi-centre trial, but could be valuable, especially for evaluation of side effects.

Clinical Trials as Topic↗

Serial studies of cerebral blood flow using 99Tcm-HMPAO: a comparison with 133Xe.

We have compared the regional distribution of 99Tcm-HMPAO with regional cerebral blood flow (rCBF). CBF was measured by single photon emission computerized tomography (SPECT) using a TOMOMATIC 64 after 133Xe inhalation in 41 patients. With the same SPECT device the distribution of 99Tcm-HMPAO was measured after i.v. injection. High resolution (HR) and low resolution (LR) studies were performed yielding a resolution of 6 to 10 mm (HR) and 15 to 20 (LR). 99Tcm-HMPAO images showed close resemblance to xenon-133 CBF tomograms. Only about 20% of the (decay corrected) brain counts were lost during the first 24 h post injection. A slight decrease in contrast was measured comparing side-to-side asymmetry ratios from the serial studies. This loss of contrast is mainly due to back-diffusion and clearance of a part of the 99Tcm-HMPAO complex from the brain. It could be corrected for by a linearization algorithm. The slight loss of contrast will not be of any importance for the clinical use of this tracer complex.

Brain↗

High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease).

Pure sensory stroke (PSS) is typically caused by a lacunar infarct located in the ventral-posterior (VP) thalamic nucleus contralateral to the paresthetic symptoms. The lesion is usually so small that it cannot be seen on computerized tomography (CT), as illustrated by our case. In our moderately hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen. In addition, NMRI unexpectedly showed diffuse periventricular demyelinization as well as three other lacunar infarcts, i.e., findings characteristic of subcortical arteriosclerotic encephalopathy (SAE). This prompted psychometric testing, which revealed signs of mild (subclinical) dementia, in particular involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric distribution of cerebral blood flow (CBF), with an 18% lower value in the right parietal cortex compared to the left side; this indicated asymmetric disconnection of the cortex by the SAE. Thus, the tomograms of the functional parameter, CBF, correlated better with the deficits revealed by neuropsychological testing than by CT or NMRI.

Aged↗

Home readings of blood pressure in assessment of hypertensive subjects.

Out-patient clinic blood pressure (OPC-BP) was compared to home blood pressure (Home-BP) measured three times daily during a two week period in 122 consecutively referred hypertensive subjects. A semi-automatic device (TM-101) including a microphone for detection of Korotkoff-sounds, self-deflation of cuff pressure and digital display of blood pressure was used. Mean difference between OPC-BP and Home-BP was systolic +13 mm Hg (range -21 - +100 mg Hg) and diastolic +5 mm Hg (range -27 - +36 mm Hg). Although a significant correlation could be demonstrated between Home-BP and OPC-BP, the inter-individual scatter was pronounced and unpredictable from the hypertensive organ damages. It is argued, that home readings should be used to greater extent in the evaluation of patients with hypertension.

Blood Pressure Determination↗

Evaluation of a 99Tcm bound brain scanning agent for single photon emission computed tomography.

D,L HM-PAO-99Tcm (PAO) is a lipophilic tracer complex which is avidly taken up by the brain. We have compared the regional distribution of PAO with regional cerebral blood flow (CBF). CBF was measured by single photon emission computed tomography (SPECT) by Tomomatic 64 after 133Xe inhalation in 41 patients. With the same SPECT the distribution of PAO was measured after intravenous injection. High resolution (HR) and low resolution (LR) studies were performed yielding a resolution of 6-10 mm (HR) and 15-20 mm (LR). PAO images showed close resemblance to 133Xe CBF tomograms. Only 20 per cent of the (decay corrected) brain counts were lost during 24 hours.

Brain↗

Home readings of blood pressure in hypertension.

Out-patient-clinic blood pressure (OPC-BP) was compared to blood pressure taken at home (Home-BP) measured three times daily during a two week period in 66 consecutively referred hypertensive subjects. A semi-automatic manometer was used (TM-101) which included a microphone for detection of Korotkoff sounds, self-deflation of cuff pressure and digital display of blood pressure. Mean difference between OPC-BP and Home-BP was systolic +14 mmHg (range -20/+100 mmHg) and diastolic +5 mmHg (range -27/+28 mmHg). Although a significant correlation could be demonstrated between Home-BP and OPC-BP, the inter-individual scatter was pronounced. There was no preponderance of patients with hypertensive organ damage among those with high OPC-BP or Home-BP. It is proposed that home readings should be included in the assessment and control of patients with hypertension, especially among badly controlled subjects and those with borderline hypertension.

Adolescent↗

Monitoring progression of diabetic nephropathy.

Glomerular filtration rate (GFR, single bolus 51Cr-EDTA technique), serum creatinine and serum beta 2-microglobulin concentrations were measured simultaneously in 49 insulin-dependent diabetics with diabetic nephropathy. GFR ranged from 148 to 23 ml/min/1.73 m2. Inverse serum concentrations of creatinine and beta 2-microglobulin showed a significant correlation with GFR over the whole range of values, r = 0.87 and r = 0.90, respectively (p less than 0.001). In the 31 patients with a GFR less than 80 ml/min/1.73 m2, serum concentration of creatinine and beta 2-microglobulin were within the normal range in 12 and 9 patients, respectively. With GFR below 60 ml/min/1.73 m2, all patients had elevated serum beta 2-microglobulin concentrations, while 24% of the patients still had normal creatinine concentration. Linear regression analysis between log GFR and log serum beta 2-microglobulin showed a better relationship than between log GFR and log serum creatinine, slope -0.90 and -0.57, respectively, p less than 0.01. A prospective study for up to 70 months was performed in 18 of the patients. The study showed a closer relationship between the individual rate of decline in log GFR and log serum beta 2-microglobulin compared to log GFR versus log serum creatinine, p less than 0.01. Neither serum creatinine nor serum beta 2-microglobulin can be used as methods for screening of early impairment of renal function (GFR less than 80 ml/min/1.73 m2 in diabetic nephropathy. Our study suggests that serum beta 2-microglobulin is more ideal endogenous marker for GFR estimation than serum creatinine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗