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Biomedical subjects

K Winther

Publications and source records attributed to K Winther.

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

Beneficial effect of isradipine on the development of left ventricular hypertrophy in mild hypertension.

The objective of this study was to analyze the long-term hemodynamic effects of the calcium antagonist isradipine in mild hypertension compared with those of the beta 1-selective adrenoceptor antagonist atenolol, focusing in particular on the development of cardiac hypertrophy. Ten male patients with mild essential hypertension were entered into a double-blind crossover study. Examinations were carried out after 2 weeks of placebo run-in, and after 6 and 12 months of active treatment. Mean resting blood pressure was reduced from 115 +/- 12 mm Hg to 106 +/- 12 mm Hg with atenolol, and to 107 +/- 8 mm Hg with isradipine. The increase in the product of heart rate times blood pressure was significantly greater during isradipine treatment, as was the maximum exercise capacity. Left ventricular mass was increased from 228 +/- 36 g to 305 +/- 68 g with atenolol whereas it remained unchanged with isradipine (254 +/- 55 g). The results indicate that antihypertensive treatment with isradipine as monotherapy may prevent the development of left ventricular hypertrophy whereas treatment with atenolol as monotherapy does not appear to offer this possibility.

Aged↗
PubMed1993

Beneficial effects of intermittent suction and pressure treatment in intermittent claudication.

The present study reports on the effects of a physical treatment modality in patients with intermittent claudication. During this treatment a major part of the skin surface is subjected to intermittent suction and pressure. In a previous, preliminary study the authors found a beneficial effect of this treatment in intermittent claudication. The study included 34 patients with moderate, stable intermittent claudication. Twenty-two patients participated in a double-blinded, randomized trial comparing the effects of 25 treatments to 25 placebo applications given over a period of two months. Twelve patients participated in an open trial investigating the possible effects of the treatment on platelet aggregation and fibrinolysis. Pain-free and maximal walking distances were measured on a treadmill, and systolic blood pressure was measured on the upper limb, the ankle, and the first toe bilaterally. The threshold for adenosine diphosphate (ADP)-induced platelet aggregation was tested, and the fibrinolytic activity was estimated from the euglobulin clot lysis time. Active treatment resulted in significant improvements in pain-free and maximal walking distances, whereas no changes could be found during placebo administration. The treatment caused significant increments in the ADP thresholds for platelet aggregation, while the effects on fibrinolysis were uncertain. It is concluded that intermittent suction and pressure treatment offers a new approach for conservative treatment of intermittent claudication.

Aged↗
PubMed1993

Decreased platelet activity without change in fibrinolytic activity after low dosages of fish oil.

The effects of low-dose (350 mg daily) polyunsaturated fatty acids from fish oil, either in gelatine capsules or microencapsulated, were investigated in a non-blind, randomized, crossover study of 12 healthy male volunteers. The authors measured the incorporation of eicosapentaenoic acid (EPA) into platelets membranes, platelet aggregability by adenosine diphosphate (ADP) and adrenaline, and fibrinolytic activity as euglobulin lysis time, after two and six weeks of therapy. Both formulations resulted in increased incorporation of EPA into platelet membranes, and the microencapsulated formulation also significantly increased the platelet level of ADP for irreversible aggregation (by about 60%). Fish oil in gelatine capsules had a smaller, non-significant effect in the same direction. Both formulations reduced adrenaline-induced aggregability, but the effects did not attain significance. Neither formulation altered fibrinolysis. The data show that low doses of fish oil in microencapsulated form significantly lower platelet aggregability, without affecting fibrinolysis.

Adenosine Diphosphate↗
PubMed1993

A botanical compound, Padma 28, increases walking distance in stable intermittent claudication.

Thirty-six patients with a median age of sixty-seven years and a median duration of intermittent claudication of five years were randomized to either active treatment with Padma 28 or placebo. The effect of treatment was quantified by measurements of systemic and peripheral systolic blood pressures and by measurements of the pain-free and the maximal walking distance on a treadmill. The ankle pressure index (ankle systolic pressure/arm systolic pressure) was calculated. The group randomized to active treatment received two tablets bid containing 340 mg of a dried herbal mixture composed according to an ancient lamaistic preparation (Padma 28). After active treatments, administered over a period of four months in a double-blinded, randomized design, the patients allocated to this group attained a significant increase in the pain-free walking distance from 52 m (20-106) to 86 m (24-164; P < 0.05) and in the maximal walking distance from 115 m (72-218) to 227 m (73- > 1,000; P < 0.05). The patient-group receiving placebo treatments did not show any significant changes in either the painfree or the maximal walking distance. The authors could not demonstrate any significant changes in the ankle pressure index either during active or during placebo treatment. In conclusion, this study has shown that treatment with Padma 28 over a period of four months significantly increased the walking distance in patients with stable, intermittent claudication of long duration.

Aged↗
PubMed1992

Effects on platelet aggregation and fibrinolytic activity during upright posture and exercise in healthy men.

The circadian variation of acute myocardial infarction suggests that daily activities such as assuming the upright posture and performing different daily activities may trigger the onset of coronary thrombosis. Such triggering may result from unfavorable alterations in the balance between the prothrombotic and antithrombotic properties of the blood. The present study compares the effects of 2 common daily activities, assuming the upright posture and exercise, on platelet aggregation and fibrinolytic activity. In healthy male subjects, assuming the upright posture in the morning significantly increased platelet aggregation and produced only a moderate increase in fibrinolytic activity within 10 minutes. These changes were still present after 90 minutes in the upright posture. Supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before initially assuming the upright posture in the morning. Return to the supine posture for 45 minutes resulted in levels of fibrinolytic activity and platelet aggregation comparable to that observed before the initial assumption of upright posture. The changes recurred when upright posture was taken later in the day. Exercise did not increase platelet aggregation to levels beyond that produced by the upright posture, but was associated with a marked increase in fibrinolytic activity. Thus, exercise and upright posture produce distinctive alterations in the thrombogenic potential of the blood that may influence the timing of clinical vascular events.

Adult↗
PubMed1992

[Preclinical and prenatal diagnosis of familial adenomatous polyposis].

In order to investigate the possibility of preclinical and prenatal genetic diagnosis of familial adenomatous polyposis (FAP) by means of DNA-systems and other markers, blood samples were collected from 246 persons in 29 families, including 90 with the clinical diagnosis FAP and 73 clinically unaffected first degree relatives (persons at risk). The material was studied with up to 4 DNA-marker systems located in the region around the disease gene. Among the first degree relatives eight (11%) had probably inherited the disease gene, while 31 persons (42%) in this risk group had probably not inherited the gene. It was not possible to evaluate the risk in the remaining 34 persons (47%). In 45 (85%) out of 53 persons under 40 years the DNA-systems were informative, so that it would be possible to offer the option of prenatal diagnosis. It is concluded that preclinical and possibly prenatal genetic diagnosis may be offered; but the current practice of prophylactic proctosigmoidoscopic surveillance should be maintained.

Adenomatous Polyposis Coli↗
PubMed1992

Rapidity and duration of platelet suppression by enteric-coated aspirin in healthy young men.

The recent demonstration of aspirin's ability to prevent and reduce the severity of myocardial infarction has led to a marked increase in its use and to a need for information regarding the time-course of onset and offset of its antiplatelet effect. A study of healthy men was conducted to determine (1) the rapidity of onset of inhibition of platelet aggregation in response to adenosine diphosphate, and thromboxane A2 production after chewed enteric-coated aspirin (325 mg, n = 10); and (2) the duration of platelet inhibition after cessation of enteric-coated aspirin (325 mg) every other day for 14 days (n = 10). When chewed, enteric-coated aspirin greatly inhibited platelet aggregation response to adenosine diphosphate and thromboxane A2 production within 15 minutes. Complete recovery of platelet aggregation occurred in half of the subjects by day 3, and in 80% of the subjects by day 4; the platelet response was not affected by exercise. This study demonstrates a rapid onset of aspirin's antiplatelet effect and provides information relevant for optimal timing of initiation of aspirin for acute conditions such as myocardial infarction and unstable angina, and cessation of aspirin before surgery.

Adenosine Diphosphate↗
PubMed1992

Enhanced risk of thromboembolic disease in hypertension from platelet hyperfunction and decreased fibrinolytic activity: has antihypertensive therapy any influence?

Enhanced platelet function and a decrease in fibrinolytic activity have been reported in patients with mild hypertension after treatment with various nonselective beta-blockers. Until now, such changes have not been reported during treatment with beta 1-selective drugs or with agents that have intrinsic sympathomimetic activity. The impact of angiotensin-converting enzyme inhibitors and diuretics on platelet function and fibrinolytic activity has not been fully elucidated. Calcium antagonists of various types, however, are known to decrease platelet release in vivo whereas their effects on platelet aggregation and fibrinolytic activity are less clear. The new dihydropyridine calcium antagonist isradipine, when tested in a group of patients with mild hypertension, resulted in a decrease in platelet aggregation, a shortened euglobulin clot-lysis time, and a dramatic increase in t-PA (tissue-plasminogen activator) activity after 14 days of treatment. These changes remained stable throughout the 1-year study period. The fact that antihypertensive therapy does not always result in the hoped-for prolongation of life, despite satisfactory blood pressure reduction, may be in part due to an unfavorable impact on various components of the blood-clotting system.

Antihypertensive Agents↗
PubMed1991

Platelet aggregation and fatty acid composition of platelets in type 1 diabetes mellitus.

A raised content of arachidonic acid in platelets from diabetic patients with retinopathy was found without differences in platelet aggregation: platelet aggregability was not related to platelet fatty acid composition. In diabetes, platelet aggregation was inversely correlated to non-esterified fatty acids in plasma and may suggest an inhibiting effect. Mean platelet volume was raised in the diabetic patients, but without hyperaggregability. The findings do not exclude a relationship between platelet fatty acids and platelet aggregability, but suggest that variations in levels of non-esterified fatty acids in plasma might interfere with platelet aggregation.

Adult↗
PubMed1991

[LongoVital in the prevention of recurrent aphthous stomatitis. 1].

LongoVital (LV) (DK. reg. no. 5178/75) is a herbal based tablet enriched with recommended doses of vitamins. The present study was undertaken to investigate prevention of recurrent aphthous ulceration (RAU) during daily intake of LV for six months as compared with placebo in a double-blind, randomised clinical, cross-over 1-year study. The population comprised 29 otherwise healthy minor RAU patients (18F, 11M) mean age 36 (18-67), with an estimated average number of recurrences the previous year of 12.8 (3-30). The number of recurrences was significantly reduced on treatment with LV during the latter four of the six months (p less than 0.01) where 31% were totally free of recurrences. Subjective all-over evaluation of treatment period was significantly in favour of LV. LV induced no adverse reactions and is the first harmless systemic treatment which has proved better than placebo in the prevention of RAU.

Adult↗
PubMed1991

[Immunomodulating effect of LongoVital in patients with recurrent aphthous stomatitis. 2].

LongoVital (LV) (DK. reg. no. 5178/75) is a herbal-based tablet enriched with recommended doses of vitamins. Peripheral lymphocyte subsets: T-helper/CD4 (OKT4+) and T-suppressor/cytotoxic/CD8 (OKT8+) were studied quantitatively in 31 otherwise healthy patients with minor recurrent aphthous ulceration (RAU) during six months' daily LV intake in a double-blind, randomised, crossover 1-year study. Fourteen had had LV during the first six months (GrA) and 17 LV during the latter six months (GrB). OKT4+ percentages increased significantly during the LV period in both groups (p less than 0.05). OKT8+ percentages increased in both groups, however, only significantly in GrA (P less than 0.05). It is concluded that LV acts as an immunostimulator in patients with RAU and that the increase in T-lymphocyte subsets may account for the previously reported benefit of LV in RAU prevention.

Adult↗
PubMed1991

Decreased fibrinolytic activity and increased platelet function in hypertension. Possible influence of calcium antagonism.

Twelve patients with mild hypertension were compared, after 14 days of placebo, with an age- and gender-matched group of 12 healthy volunteers for platelet aggregability and fibrinolytic activity. Following this, 10 of the 12 hypertensives were treated with the calcium antagonist isradipine for 12 months. Blood was drawn for determinations of platelet aggregation and fibrinolytic activity after two weeks and 12 months of treatment. Platelet aggregation tended to increase in the hypertensives compared with controls, indicated by a lowering of the adenosine diphosphate (ADP) threshold value for irreversible aggregation. Tissue-plasminogen activator (t-PA) activity was significantly decreased in hypertensives compared to controls (P less than .05). During therapy, platelet aggregation decreased and t-PA activity increased (P less than .05). The present data suggest that fibrinolytic activity is decreased and platelet aggregation increased in mild hypertension. Besides the blood pressure-lowering effect, isradipine may protect against thromboembolic diseases by modifying platelet function and fibrinolytic activity.

Adult↗
PubMed1991

Platelet-associated immunoglobulins in patients with primary Sjögren's syndrome.

Ten patients with primary Sjögren's syndrome (7 females) were examined in order to evaluate whether in vivo-bound platelet-associated immunoglobulins (PAIg) and/or in vitro binding of circulating Ig to normal platelets influences platelet function. With an ELISA technique it was found that 9/10 patients had increased amounts of in vivo PAIgG, 4/10 patients of in vivo PAIgA and 5/10 patients of in vivo PAIgM. There was no correlation between patients platelet aggregability and the presence of in vivo PAIg. Incubation of platelets from a healthy person with plasma from the 10 patients caused in vitro binding of IgG in 7/10 cases, of IgA in 0/10 cases and of IgM in 1/10 cases. Adenosine diphosphate (ADP)-induced aggregability of the normal platelets was impaired in 7/10 incubation experiments (no correlation to in vitro PAIg) and unchanged in 3/10 cases. Epinephrine- and collagen-induced platelet aggregability was unchanged in all cases. It is concluded that increased amounts of in vivo and in vitro PAIg seem to occur frequently in patients with primary Sjögren's syndrome, but do not influence platelet aggregability.

Blood Platelets↗
PubMed1991

Association of wake time and the onset of myocardial infarction. Triggers and mechanisms of myocardial infarction (TRIMM) pilot study. TRIMM Study Group.

A morning increase in onset of acute myocardial infarction (MI) has been documented, but its association with wake time and possible triggering events is unclear. The community-based, ongoing Triggers and Mechanisms of Myocardial Infarction (TRIMM) study was designed to investigate the factors associated with the transition from chronic coronary artery disease to acute MI. During the pilot phase in 1989, 224 consecutive hospitalized MI patients (176 men and 48 women, aged 60.3 +/- 9.2 years) of the prospectively defined Monitoring of Trends and Determinates of Cardiovascular Disease (MONICA) Augsburg MI register were interviewed 16.8 +/- 6.5 days after the event. The frequency of onset of MI was significantly higher (p less than 0.01) during the morning from 6 to 9 AM compared with other times of day. After adjustment for individual wake times, the peak of onset of MI was markedly sharper; the relative risk of MI during the 3-hour peak interval (the 3 hours after awakening) compared with other times of day increased from 1.8 (95% confidence interval, 1.3-2.4) to 2.4 (95% confidence interval, 1.8-3.1). Sixty-seven percent of the patients reported possible acute triggers of MI and/or unusual life events; among those, 52% reported stress or emotional upset. The TRIMM pilot study demonstrated the feasibility of a community-based study of possible triggering events of MI. The circadian variation of MI appears to result primarily from increased onset after awakening. This narrowing of the time frame of increased risk of MI should facilitate study of pathogenic mechanisms and aid in the design of more effective preventive regimens.

Adrenergic beta-Antagonists↗
PubMed1991

Does antihypertensive therapy affect the natural protection against thrombosis?

Fibrinolytic activity was measured in a 14-day placebo-controlled study of propranolol and the calcium antagonist isradipine in 20 mildly hypertensive patients (diastolic blood pressure 95-115 mm Hg) compared with 24 healthy volunteers. The parameters under study included euglobulin clot-lysis time, and tissue-plasminogen activator activity and its inhibitor (PAI). The two drugs exerted equal antihypertensive effects in the patients who had raised blood pressure, but had markedly different actions on the fibrinolytic system. Propranolol substantially reduced the fibrinolytic activity in both the hypertensive and healthy control groups. Isradipine, on the other hand, had no effect on fibrinolytic activity in the controls, but augmented the activity in the hypertensive subjects. The possible mechanisms for the different actions of the two agents may be related to the vascular endothelium.

Adult↗
PubMed1991

Platelet function and fibrinolytic activity in hypertension: differential effects of calcium antagonists and beta-adrenergic receptor blockers.

Platelet function was investigated in healthy volunteers and patients with essential hypertension by measurement of thresholds for ADP and adrenaline-induced aggregation and plasma concentrations of platelet factor 4 (PF-4) and beta-thromboglobulin (beta-TG) after administration of antihypertensive drugs. Fibrinolytic activity was investigated by the euglobulin clot lysis time (ECLT) and tissue plasminogen activator (t-PA) activity. Compared to normotensive controls, patients with essential hypertension showed increased aggregation as evidenced by a decrease in ADP thresholds for ex vivo platelet aggregation. ECLT was significantly prolonged and t-PA significantly lowered, indicating impaired fibrinolytic activity in mild hypertension. In different studies, we have shown that various antihypertensive drug regimens differ in their effects on platelet function and fibrinolytic activity when given to healthy volunteers or patients with mild-to-moderate essential hypertension. In normal volunteers, treatment with the calcium antagonists verapamil, nifedipine, and felodipine lowered plasma concentrations of PF-4 and beta-TG, indicating a reduced platelet activity in vivo. Fibrinolytic activity was not influenced by calcium antagonist treatment in the normal volunteers. Interestingly, however, t-PA increased significantly in the hypertensive group. When compared to placebo or beta 1-selective blockers, propranolol, a non-selective beta-adrenergic blocker without partial agonist activity, reduced ADP and adrenaline threshold values for ex vivo platelet aggregation in hypertensive subjects and impaired fibrinolytic activity in the normal volunteers as well as in the hypertensive groups by increasing ECLT and reducing t-PA. Hypothetically, the effects of antihypertensive drugs on platelet function and fibrinolytic activity could be of importance for their proposed actions on cardiovascular morbidity and mortality.

Adrenergic beta-Antagonists↗