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Biomedical subjects

J R Ostergaard

Publications and source records attributed to J R Ostergaard.

At least 55 records · Page 3Linked to original sources
PubMed1986

HLA antigens and complement types in patients with intracranial saccular aneurysms.

The occurrence of HLA-A, -B, -C antigens and the HLA controlled complement factors (Bf, C2, C4) was investigated in an unselected group of 116 consecutively admitted patients with intracranial saccular aneurysms, and compared to that of healthy controls (blood donors). When multiplying the p-values with the number of comparisons made, none remained significant. However, a rather high etiologic fraction of the BfS gene (0.59) was obtained. Moreover, for HLA -B7 a significant deviation from the Hardy-Weinberg equilibrium with an increase of homozygotes was found. Due to linkage disequilibria this could indicate a strong association between HLA-DR2 and saccular aneurysms. The presence of HLA-DR2 was therefore investigated in a series of 15 aneurysm patients used as cadaver kidney donors and not included among the 116 consecutively admitted patients. In this group the HLA-DR2 antigen frequency was significantly increased (66.7% vs. 29.7%, p less than 0.01). The present study thus demonstrates an association of saccular aneurysm and the major histocompatibility complex and shows the existence of a genetic predisposition to saccular aneurysm.

Complement C2↗
PubMed1986

The C3-F gene in patients with intracranial saccular aneurysms.

The C3-F gene has previously been found associated with atherosclerotic vascular diseases. The occurrence of the C3-F gene was therefore investigated in a group of 110 hospitalized patients with intracranial saccular aneurysms. The C3-F gene occurred equally often in patients and controls. In patients with a ruptured aneurysm, however, the C3-F gene frequency was significantly increased in subjects aged 40-49 years followed by a marked and statistically significant decline with increasing age. The findings suggest that the C3-F gene may be a risk factor for early aneurysm rupture.

Adolescent↗
PubMed1985

A long-term follow-up study of juvenile aneurysm patients.

The long-term outcome in 26 patients following operation of intracranial saccular aneurysms before the age of twenty is presented. The duration of follow-up ranged from 4 to 33 years (mean 14 years). The oldest patient is now 51 years old. 19 patients (73%) made a complete or good recovery with resumption of normal life. Only one patient was severely disabled and dependent for daily support. Aspects of social outcome such as working conditions and family relationships were encouraging. No association between presence of vasospasm in the acute phase of the disease and the long-term outcome was demonstrated. In one case rupture of a previously undetected aneurysm had occurred during the followed-up period.

Adolescent↗
PubMed1985

The biological relevance of the protein binding of diazoxide.

The biological importance of the binding of diazoxide to serum protein was studied in vitro. Contractions in the rings of the rabbit pulmonary artery evoked by electrical field stimulation or exogenous noradrenaline (NA) were studied in the absence and presence of serum albumin (45 g/l) in Krebs-Henseleit (K-H) solutions. Diazoxide concentrations up to 128 micrograms/ml in the K-H solution and to 256 micrograms/ml in albumin K-H solutions diminished the contractions and albumin reduced this diminishing effect. Because of an apparent binding of exogenous noradrenaline to albumin only the experiments with electrical field stimulation were used to assess the biological importance of the protein binding of diazoxide. At 2 micrograms/ml of diazoxide the free drug fraction determined by ultrafiltration was 5% but determined by our biological method the free (active) fraction was 65%. In accordance with a previous clinical study we conclude that the binding of diazoxide to serum protein is important for the transportation of the drug to the arteriolar wall which apparently has a much higher affinity for the drug than serum albumin.

Animals↗
PubMed1985

Incidence of multiple intracranial aneurysms. Influence of arterial hypertension and gender.

Theoretically, if arterial hypertension plays a role in aneurysm formation, it might also be associated with a higher incidence of multiple aneurysms as compared to their occurrence in normotensive patients. In an unselected series of 737 aneurysm patients, the structure of dependence between 1) number of aneurysms, 2) patients' sex, 3) patients' age, and 4) the presence or absence of hypertension was analyzed using contingency-table analysis. Evidence of arterial hypertension was determined by means of three complementary criteria of hypertension. A significant mutual state of dependence was demonstrated between the presence or absence of hypertension and the number of aneurysms, and between number of aneurysms and sex of the patient. In addition, for patients with a given number of aneurysms, the action of gender was independent of the blood pressure level. No interaction between the age of the patient and the number of aneurysms could be demonstrated. In order to quantify the relative contribution of the patients' sex, the patients' age, and the presence of hypertension to multiplicity of aneurysms, a probability model for multiplicity of aneurysms was estimated by logistic-regression analysis. It was demonstrated that the most important factor explaining multiplicity was the presence of hypertension, whereas the age of the patient had no influence. A "pure" effect of gender was revealed, indicating that females are significantly more susceptible to aneurysm formation, even in cases without arterial hypertension.

Adult↗
PubMed1984

Association of intracranial aneurysm and arteriovenous malformation in childhood.

The simultaneous occurrence in the same patient of an intracranial saccular aneurysm and an arteriovenous malformation (AVM) is a well-known phenomenon. Usually the aneurysms are related anatomically to the arteries supplying the AVM, and it is generally accepted that the aneurysms are caused by hemodynamic stresses resulting from the presence of an AVM. Because patients with both an AVM and an aneurysm are older than those presenting with an AVM alone, a time factor seems essential in the development of the aneurysm accompanying an AVM. In this article, the case reports of two children are presented. They both had a symptom-producing AVM and an attendant saccular aneurysm. The malformations were anatomically closely related and the significance of hemodynamic stresses in the development of the aneurysms cannot be neglected. However, in these two cases, the time factor obviously cannot be of vital importance. Therefore, another factor, possibly in the form of a vascular collagen defect, may be suspected as essential in the formation of aneurysms during childhood. The character of this defect is briefly discussed.

Child↗
PubMed1983

Intracranial arterial aneurysms in children and adolescents.

Throughout the period 1943 to 1980, 1368 patients with verified intracranial saccular aneurysms were treated in the University of Aarhus neurosurgical department. Forty-three (3.1%) patients (25 boys and 18 girls) were 19 years old or younger, and 33 (77%) had an onset of symptoms typical of subarachnoid bleeding. Using the classification system of Hunt and Hess as a basis for clinical assessment on admission, 58% of the patients could be placed in Grade I or II. Cerebral vasospasm was demonstrated in 53% of the patients undergoing angiography between the 4th and 16th day after hemorrhage. There was no increased morbidity or mortality in the group of patients with vasospasm, and no cerebral infarction was demonstrated at necropsy. Therefore, it is possible that vasospasm is of minor prognostic significance in children. In 15 patients (37%), aneurysm rupture was accompanied by intracerebral hematoma. The mortality rate in this group of 15 patients was 50%, whereas in the group without hematoma it was 26%. The overall mortality rate was 33%. The surviving 29 patients were followed for 3 months to 14 years. Twenty-three patients made a good recovery (80% of survivors and 54% of the total series), five were moderately disabled, and one was severely disabled.

Adolescent↗
PubMed1982

Nitroglycerin for ergotism. Experimental studies in vitro and in migraine patients and treatment of an overt case.

Ergotamine was used to induce arterial contraction in vitro (measurement of isometric tension in segments from 3 human temporal arteries) and in vivo (peripheral systolic blood pressure measured by strain gauge plethysmography in 5 migrainous patients). In both these models of ergotism, the directly acting vasodilator nitroglycerine (NTG) effectively relieved the ergotamine-induced arterial contractions. A case of ergotism treated successfully with NTG infusion is reported. The diagnosis was based on history and measurement of peripheral systolic blood pressure by strain gauge plethysmography. The latter technique was also used to monitor the response to treatment for 20 h. Blood levels of ergotamine during ergotism were in the therapeutic range. Possible explanations for this finding are discussed.

Adult↗
PubMed1981

Altered extracranial vascular reactivity in patients with cerebral arterial aneurysm: an in vitro study.

Isolated human superficial temporal arteries were constricted by the addition of potassium, norepinephrine, and 5-hydroxytryptamine. Different responses occurred when the vessels were taken from patients with ruptured intracranial aneurysm and from patients without cerebral aneurysm. In the aneurysm group, significantly stronger contractions were demonstrated upon exposure to potassium and 5-hydroxytryptamine. Because these agents increase the movement of extracellular calcium into smooth muscle cells in the excitation-contraction coupling process, it is suggested that, in vessels from aneurysm patients, there is enhanced influx of calcium across the cell membrane and that cerebral vasospasm is thus not due to extravascular actions alone.

Adult↗
PubMed1981

Effects of 5-hydroxytryptamine and ergotamine on human superficial temporal artery.

Isometric tension was recorded in ring preparations of human superficial temporal arteries contracted by noradrenaline (NA), 5-hydroxytryptamine (5-HT), and ergotamine. In contrast to NA and 5-HT, ergotamine induced long-lasting contractions refractive to additional stimulations and resistant to repeated wash-out. When tested against 5-HT, ergotamine acted as a non-competitive antagonist. When repeating the 5-HT stimulations (4.7 x 10(-5) M) the contractile response decreased indicating tachyphylaxis to this agent. As ergotamine revealed both a vasoconstrictive and a 5-HT-blocking activity, the beneficial effect in migraine may be by an interference during both the vasoconstrictory and vasodilatory phases.

Adult↗
PubMed1981

Effects of ergotamine on isolated human vessels.

In isolated human mesenteric and crural veins, ergotamine induced long-lasting contractions. These contractions were resistant to repeated wash-out and were not affected by alpha-adrenoceptor blockade, but could be abolished by removal of extracellular calcium or by the presence of the calcium-blocker nifedipine. In contrast to its effect on human mesenteric and crural veins, ergotamine had no contractile effect, but a marked relaxant effect on mesenteric arteries mediated via blockade of alpha-receptors. The ergotamine-induced contraction was not affected by indomethacin (0.28--2.8 microM) nor was it influenced by serotonin (5-HT). In both mesenteric and crural veins, the ergotamine-induced contraction was diminished by the 5-HT blocking agent, methysergide. In veins, development of tachyphylaxis to 5-HT was demonstrated. It is concluded that ergotamine has a direct contractile effect on isolated human mesenteric and crural veins. These effects are dependent on unhindered influx of extracellular calcium and are at least partly mediated via 5-HT receptors. In mesenteric arteries, ergotamine acted as an alpha-adrenoceptor blocker, and had no contractant effect.

Adult↗
PubMed1980

Calcium antagonistic effects of terodiline in rabbit aorta and human uterus.

The possible calcium antagonistic action of the anti-anginal drug terodiline was investigated by two experimental techniques. In isolated preparations of rabbit aorta and pregnant human uterus exposed to a calcium-free medium and then depolarized by potassium, terodiline in concentrations of 4.5--36 microM inhibited contractions produced by cumulative addition of calcium to the extracellular medium. This effect of terodiline could be reversed by high concentrations of calcium. Within the same concentration range, terodiline also reduced potassium-induced 45Ca influx in isolated aorta without affecting calcium efflux. It is suggested that terodiline, which structurally has similarities to prenylamine and fendiline, like these drugs can be classified as a calcium antagonist.

Adult↗
PubMed1980

Anticholinergic and calcium antagonistic effects of terodiline in rabbit urinary bladder.

The effects of terodiline on contractions induced in isolated rabbit detrusor by carbachol and potassium, and by electrical field stimulation were investigated. Terodiline relaxed preparations contracted by carbachol and potassium and, when added 15 min before stimulation, decreased the contractile responses to these agents in a concentration-dependent way. Terodiline more effectively inhibited carbachol than potassium induced contractions. The "pure" calcium antagonist nifedipine had the opposite effect. Both atropine and terodiline caused a parallel shift to the right of the concentration-response curve to carbachol. The maximum contractile tension and slope were not affected, suggesting a competitive antimuscarinic effect within the concentration range used. Atropine was approximately 750 times more potent than terodiline. The maximum inhibitory effect of atropine and the calcium antagonist nimodipine on the electrically induced response were 40% and 69%, respectively. Terodiline caused complete inhibition of the response, as also did a combination of nimodipine and atropine. --The results suggest that terodiline in low concentrations has mainly an antimuscarinic action. To this, a calcium antagonistic effect is added at higher concentrations. The two-fold action of the drug makes it an effective inhibitor of bladder contraction, and an interesting tool for investigations of bladder contractility.

Animals↗