Age and features of adrenal cortical function in cerebral circulatory disorders

The indices of glucocorticoid and androgen activity in the adrenal cortex (the level of circulating eosinophils, the daily urine excretion of 17 OCS and 17 CS) and the functional reserve after an ACTH loading was studied in 2 groups of patients with disorders of cerebral circulation under 45 years of age (247 cases) and over 55 (234 cases). In the acute period of a cerebral stroke there was an increase of the glucocorticoid activity which was more definitely expressed in the younger group and a certain inhibition of the androgen function seen mainly in the older group. In transient disorders of cerebral circulation significant age difference in the functioning of the adrenal cortex was not established. In the period following a stroke the established and potential reserves of the adrenocortical glands were distinctly decreased in patients above 55 years and practically unchanged in the younger group.     

Diagnostic value of determining hemoglobin in cerebrospinal fluid in acute cerebral circulatory disorders

The results of hemoglobin determination in the CSF by the method of fluorescence microscopy in 195 patients speaks in favor of relative diagnostical importance of hemoglobin in the supra fall-out CSF for establishing the character of the stroke. The following circumstances testify to this fact: 1) in an artificial admixture of blood in the CSF in some cases there may be hemolysis of "passing" erythrocytes; 2) in a genuine admixture of blood, tests of hemoglobin in the centrifugate of the CSF may be negative since in some cases the transition of hemoglobin into bilirubin in the subarachmoid space occurs more rapidly than the hemolysis of erythrocytes. Thus, the hemoglobin does not accumulate in the liquid in quantities, sufficient enough to be measured by the existing methods; 3) in a large amount of artificial blood admixture, even without a hemolysis of "passing" erythrocytes the hemoglobin tests in the centrifugate of the CSF may be positive at the expense of hemoglobin of the blood plasma.     

In vitro training model for endovascular embolization of cerebral aneurysms

We present a new in vitro model for the training of endovascular embolizations of cerebral aneurysms. The technique and laboratory set-up described allow the embolization of thin-walled, transparent silicone aneurysm models under "semi-physiologic" conditions, i.e., in a closed circulation with pulsatile flow and pressure, simulating the hemodynamic conditions encountered in biologic systems.     

The pentoxifylline and corglycon treatment of patients with circulatory encephalopathy against a background of atherosclerotic lesions of the major cerebral arteries

As many as 34 patients having stage II-III atherosclerotic dyscirculatory encephalopathy with coexisting ischemic heart disease in the presence of stenosing and occlusive lesions of major brain arteries were evaluated for effects pentoxiphyllin and corglycon on the clinical course of this medical condition as well as systemic and cerebral haemodynamics. In this series, 82.7 percent of patients derived benefit from a single intravenous infusion of pentoxiphyllin and corglycon and course treatment with these drug preparation that was evidenced by an improvement in the parameters of systemic and cerebral hemodynamics and regression of neurologic symptomatology. The results of the studies made permit recommending pentoxiphyllin in combination with corglycon for treatment of those DE patients with eukinetic and hypokinetic types systemic haemodynamics, whereas pentoxiphyllin alone--for those with hyperkinetic type of haemodynamics, taking into consideration its cardiodepressive effects.     

Role of genotypic and environmental factors in the origin of cerebral circulatory disorders in young persons

The paper is concerned with the results of a comparative analysis of clinical signs in cerebral crises, strokes and other symptoms seen in 2 groups of patients younger than 45 years of age, and differing only in the presence (104 cases) or absence (108 cases) of hereditary-familial aggravation by a cardio-vascular pathology. Although in the first group of patients there was a certain tendency towards a more severe disorder of cerebral circulation, it was not possible to mark any statistically significant differences in the clinico-biochemical indices. At the same time different negative environmental influences (alcohol abuse, brain injuries, severe acute and chronic mental traumatization, frequent exacerbations of focal chronic infections of the ENT and the lungs, etc.) and a combination of 2 or 3 of them were significantly more frequently seen in patients without hereditary aggravation (34.8%) rather then with it (10.7%). A conclusion is being made that genotypical factors do not play a decisive role in the etiology of cerebral vascular disorders in young people. They only condition a lesser stability of the organism to unfavourable environmental factors and their different combinations.     

A computational model for blood flow through highly curved arteries with asymmetric stenoses

In this paper, we develop a three dimensional model of blood flow through curved arteries with asymmetric stenoses. Firstly, the Navier-Stokes equations representing Newtonian flow are solved using PHOENICS, a computational fluid dynamics package which utilises the Finite Volume method of solution. The severity of the stenoses considered in this study vary from about 40% to about 70%. Subsequently, the model is solved for Reynolds numbers ranging from 100 to 1200. The pressure drop results show good agreement with published results. The results also show that stenoses on a bent artery has a significant effect on blood flow characteristics.     

Embolization of cerebral angiomas by catheterization of cortical arteries

A method of combined direct embolization of submillimetric cortical arteries, after preoperative arteriography, is described and 3 cases of cerebral angiomas presented with striking symptomatic improvement after embolization. Postoperative angiography in one case showed considerable diminution in the size of the angioma.     

Quantitative measurement of cerebral blood flow by the microsphere model with super-early 123I-IMP brain SPECT

Cerebral blood flow (CBF) was quantitatively measured in 6 healthy young volunteers based on "super-early" acquisition of N-isopropyl-p-[123I]iodoamphetamine (IMP) brain SPECT obtained 4-6 min after IMP injection with a three-head rotating gamma camera and the microsphere (MS) model. The ratio of radioactivity (count/pixel/min) in the conventional early SPECT image (taken 25-55 min after IMP injection) to that in the "super-early" image for each brain region negatively correlated with regional CBF value obtained with the "super-early" MS method. This indicates that wash-out of IMP from the regions with higher CBF is faster than that from the regions with lower CBF and that CBF values are underestimated with the conventional MS method in regions with higher CBF. Regional CBF was quantitatively measured with the "super-early" MS method and the ARG method, a recently developed method based on two-compartment model. The mean cortical CBF was 52.5 +/- 7.0 (ml/100 g/min, mean +/- SD) with the "super-early" MS method and 47.5 +/- 3.3 with the ARG method. The CBF values obtained with the "super-early" MS method agreed with those previously reported with positron emission tomography. Since the MS method is theoretically the simplest model, the "super-early" MS method can be applied various disorders of the central nervous system where the behavior of IMP is not fully understood.     

Experimental study of venous circulatory disturbance by dural sinus occlusion

Using a newly devised model of dural sinus occlusion, we investigated the pathophysiology of venous haemorrhage as well as venous circulatory disturbance. The superior sagittal sinus (SSS) and diploic veins (DV) were occluded in 16 cats. Intracranial pressure (ICP), cerebral blood volume (CBV) and regional cerebral blood flow (rCBF) were measured for 12 hours after the occlusion. At the end of the experiment, cerebral water content was estimated. In another 8 cats additional occlusions of cortical veins were carried out. In both groups, the blood-brain barrier permeability was evaluated with Evans blue or horseradish peroxidase. The SSS and DV occlusion produced a significant increase in ICP and CBV concomitant with a significant decrease in rCBF. Cerebral water content also increased significantly. However, there was no transition of Evans blue and horseradish peroxidase through the cerebral vessels, and no haemorrhages could be observed. In contrast, the additional occlusion of cortical veins produced haemorrhagic infarctions with Evans blue extravasation in 6 out of the 8 cats. These data suggest that dural sinus occlusion may lead to an increase in CBV and cerebral water content resulting in intracranial hypertension and decreased rCBF. The brain oedema in this model seemed to be mainly hydrostatic oedema, and might also be contributed by cytotoxic oedema. The additional occlusion of cortical veins might be essential in the development of haemorrhage in this model, and the blood-brain barrier was also disrupted in these areas.     

Treatment and prophylaxis of acute disorders of the cerebral blood circulation in patients with diabetes mellitus

Experiments were conducted on young female rats with the aid of morphological, morphometric and histochemical methods; a study was made of the adrenal glands, mammary and the thyroid glands under conditions of castration and administration of synestrol, progesterone, both sex hormones, hydrocortisone. Sex hormones proved to produce a fulminant growth of the glandular tree against the background of reduction of the functional activity of the thyroid gland and relatively high indices of the hormonal activity of the fasciculo-reticular zone of the adrenal glands. A harmonious development of the glandular tree of the mammary glands was noted only under the effect of a simultaneous administration of synesterol and progesteron. A shift in the hormonal balance in the direction of synestrol caused the appearance of pathological deviations in the mammary glands by the type of cystic mastopathy. Under conditions of castration hydrocortisone produced a moderate stimulating influence on the mammary glands only in case of a prolonged action.     

Novel mechanism by which hemoglobin induces constriction of cerebral arteries

Since oxyhemoglobin (OxyHb) is implicated in the pathogenesis of cerebral vasospasm, we have investigated the role of protein tyrosine phosphorylation in OxyHb-mediated signalling in canine cerebral arteries and cultured canine cerebrovascular smooth muscle cells. OxyHb produced a contraction of basilar artery preparations, which was reversed by genistein, an inhibitor of tyrosine kinases, and PD098059, an inhibitor of mitogen-activated protein kinase. In cerebrovascular smooth muscle cells, OxyHb induced tyrosine phosphorylation of 42, 46, 54-60 and 80-100 kDa proteins with a time-course which paralleled the contractile action of OxyHb, suggesting that these events might be functionally linked. The 42 and 60 kDa proteins were immunologically related to the mitogen-activated protein kinase, extracellular signal regulated protein kinase (ERK2), and to p60c-Src (c-Src), respectively. The increase in protein tyrosine phosphorylation was attenuated by genistein, and the phosphorylation of the 42 kDa protein (ERK2) was inhibited by PD098059. These results suggest that OxyHb-mediated signalling utilizes a protein tyrosine kinase-based mechanism.     

The treatment of hemoptysis by embolization of the systemic arteries (author's transl)

The authors present their still limited experience of embolization of systemic arteries as the treatment of hemoptysis. Their cases illustrate the indications, contra-indications, causes of failure and effectiveness of this therapeutic method in pneumology. They had to refuse who patients: in the first, the pathological bronchial artery arose from a common trunk with the intercostal which gave rise to an anterior spinal artery. The second patient showed signs of medullary involvement on injection of a pathological right intercostal artery, which in their opinion is also a contra-indication of embolization, although no anterior spinal artery was demonstrated on the arteriogrammes. Six patients were treated by embolization. In the case of one patient, treatment was a failure owing to incomplete embolization. A main esophageal pedicle supplied a high flow bronchial artery anastomosis. These important collateral esophageal vessels compromize the effectiveness of bronchial embolization.     

Diagnosis of cerebral circulatory arrest with Doppler sonography. Results of a survey

OBJECTIVES: To assess the feasibility and potential diagnostic usefulness of colour-Doppler flow imaging (CDFI) to detect complications of supra-aortic vascular bypass grafts in Takayasu's arteritis (TA). DESIGN: A prospective study. MATERIALS: Nine supra-aortic grafts in six patients with Takayasu's arteritis. METHODS: The minimal, maximal, and true colour-flow image diameters of the lumens of the grafts were measured and stenoses, occlusions, and dilatations were evaluated and compared with angiographic findings. RESULTS: The sensitivity for detection in > 50% stenoses and in total occlusions was 75% while specificity was 100%. Only one 40% stenosis had been overlooked in whole. The maximal difference of stenosis by two methods was otherwise 20%. CONCLUSIONS: CDFI was in general able to expose stenoses in supra-aortic grafts, but the lack of visibility of some grafts throughout their length cause the false results. It appears that some angiographies can be replaced by CDFI and that this is a suitable method for follow-up in symptom-free patients with grafts.     

The prognostic value of the lactate concentration and lactate/pyruvate ratio in cerebrospinal fluid following acute cerebral circulatory disorders

The study was conducted in 80 patients with ischaemic and 29 with haemorrhagic cerebral stroke. Lactate, pyruvate, the lactate/pyruvate ratio and glucose were determined in the arterial blood and lumbar CSF. A high prognostic value of the CSF lactate content was found in cases of ischaemic stroke. According to the data obtained, an elevation of the CSF lactate concentration above 4.0 mEq/l should be considered life-threatening. Haemorrhagic stroked was found to be accompanied by a reduced CSF glucose level and an elevated lactate content, as well as by a significant proportional elevation of the lactate and red blood cells count in the CSF. The conducted calculations demonstrated that 1/4 to 1/3 of the CSF lactate is formed at the expense of the glycolytic metabolism in the CSF erythrocytes. This constitutes the main reason of the discordance between the CSF lactate content in haemorrhagic stroke and the routine criteria of prognosis in ischaemic stroke. The lactate/pyruvate ratio in the CSF is of no prognostic importance in both forms of cerebral stroke.     

Mechanism of disorders of the cerebral blood supply during stress in spontaneously hypertensive rats

The immobilization- and sound stimulus-induced changes in cerebral circulation were studied in spontaneously hypertensive rats. It was found that there was a stress-induced increase in the levels of epinephrine and norepinephrine in brain tissue, which was associated with lower levels of vasoactive prostaglandins E and F2 and with their imbalance with vasodilator prostaglandins E being prevalent. The change in the cerebral ratio of biologically active substances results in cerebral blood flow autoregulation failure and development of large cerebral hemorrhages.