Activity of peripheral sympathetic efferent nerves in experimental subarachnoid haemorrhage

The efferent activity of the vertebral, cardiac and renal sympathetic nerves was recorded during the so-called "early vasospasm" period, 25-30 minutes after experimentally induced subarachnoid haemorrhage. Experiments were performed on 51 cats with methods described in Part I of our publication. The animals were held either in a sphynx-like position (Pos. I), or in head-down position (Pos. II), when the level of the cisterna magna was 2-3 cm below the level of the spinal cord, facilitating the injected blood to flow in to, and remain at the base of the brain. According to our results during the "early vasospasm" period, we could not observe such changes in the sympathetic efferent activity, which could be specific for this period. With the gradual decrease in the intracranial pressure, the sympathetic overactivity ceased, and in most cases the level of activity was similar to that of the preinjection period. Our results also indicate that because of the remarkable variability of the activity of the renal sympathetic nerve during the intracranial pressure elevation, recording the activity of one sympathetic nerve only may give misleading results concerning the activity of the whole sympathetic system.     

NMR tomography of the major blood vessels in healthy persons

Fourteen normal subjects were examined with the aid of a NMR-tomograph VMT-1100 manufactured by the Brucker Company, FRG. Two methods of image obtaining were employed, namely the recovery of inversion and spin-echo. To visualize the mesenterial vessels, image synchronization according to the ECG R wave was made use of in some cases. On axial sections the vessels showed as rounded formations with a clearly visible wall having a lighter coloration. On sagittal and coronary sections one could see vessels looking like tubular structures with a flat and even wall. The thoracic and abdominal parts of the aorta with the outgoing branches as well as the inferior vena cava were visualized well. To have a more complete visualization of the vessel wall and sites from where the vessels go out, the "zone of interest" was distinguished followed by the enlargement, which allowed a more detailed view of the objects under examination. NMR-tomography permitted obtaining information concerning the status of the vessels together with their form, size, winding and curvatures, the magnitude of the lumen of the vessels and thickness of their walls.     

Assessment of Operational Degradation of Pipeline Steels

This paper summarizes a series of the authors’ research in the field of assessing the operational degradation of oil and gas transit pipeline steels. Both mechanical and electrochemical properties of steels are deteriorated after operation, as is their resistance to environmentally-assisted cracking. The characteristics of resistance to brittle fracture and stress corrosion cracking decrease most intensively, which is associated with a development of in-bulk dissipated microdamages of the material. The most sensitive indicators of changes in the material’s state caused by degradation are impact toughness and fracture toughness by the J-integral method. The degradation degree of pipeline steels can also be evaluated nondestructively based on in-service changes in their polarization resistance and potential of the fracture surface. Attention is drawn to hydrogenation of a pipe wall from inside as a result of the electrochemical interaction of pipe metal with condensed moisture, which facilitates operational degradation of steel due to the combined action of operating stresses and hydrogen. The development of microdamages along steel texture was evidenced metallographically as a trend to the selective etching of boundaries between adjacent bands of ferrite and pearlite and fractographically by revealing brittle fracture elements on the fracture surfaces, namely delamination and cleavage, indicating the sites of cohesion weakening between ferrite and pearlite bands. The state of the X52 steel in its initial state and after use for 30 years was assessed based on the numerical simulation method.     

Prevalence of Hantaviruses Harbored by Murid Rodents in Northwestern Ukraine and Discovery of a Novel Puumala Virus Strain

In Europe, two species of hantaviruses, Puumala orthohantavirus (PUUV) and Dobrava orthohantavirus (DOBV), cause hemorrhagic fever with renal syndrome in humans. The rodent reservoirs for these viruses are common throughout Ukraine, and hence, the goal of this study was to identify the species and strains of hantaviruses circulating in this region. We conducted surveillance of small rodent populations in a rural region in northwestern Ukraine approximately 30 km from Poland. From the 424 small mammals captured, we identified nine species, of which the most abundant were Myodes glareolus, the bank vole (45%); Apodemus flavicollis, the yellow-necked mouse (29%); and Apodemus agrarius, the striped field mouse (14.6%) Using an indirect immunofluorescence assay, 15.7%, 20.5%, and 33.9% of the sera from M. glareolus, A. glareolus, and A. flavicollis were positive for hantaviral antibodies, respectively. Additionally, we detected antibodies to the hantaviral antigen in one Microtus arvalis, one Mus musculus, and one Sorex minutus. We screened the lung tissue for hantaviral RNA using next-generation sequencing and identified PUUV sequences in 25 small mammals, including 23 M. glareolus, 1 M. musculus, and 1 A. flavicollis, but we were unable to detect DOBV sequences in any of our A. agrarius specimens. The percent identity matrix and Bayesian phylogenetic analyses of the S-segment of PUUV from 14 M. glareolus lungs suggest the highest similarity (92–95% nucleotide or 99–100% amino acid) with the Latvian lineage. This new genetic information will contribute to future molecular surveillance of human cases in Ukraine.     

Comparison of methods eliciting cerebral ischaemic pressor response in the cat

Three methods of intercepting the blood supply to the brain were tested by means of X-ray angiography and by monitoring the pressor response following cerebral ischaemia. The methods were: (1) occlusion of carotid and basilar artery; (2) occlusion of carotids and vertebral arteries in the cervical canal of the third vertebra; (3) occlusion of carotid and subclavian arteries. The X-ray angiographs showed that in most cases we could close the accessory sources of the cerebral circulation and drastically reduce the blood supply to the brain of the cat. With all three methods the cerebral ischaemia evoked strong blood pressor elevation, which was weaker however when the carotid and basilar artery were clamped, in comparison with the other two methods. This may be explained by the existence of small arteries supplying the lower brain stem and originating intracranially from the vertebral artery near to the junction of the vertebral and anterior spinal artery.     

Der Einfluß von Adrenalin auf die Tätigkeit des „Sympathicus“

Zusammenfassung Adrenalin wirkt bei narkotisierten Katzen nicht direkt hemmend auf den sympathischen Tonus. Die Hemmung der sympathischen Aktionsströme nach Adrenalininjektion ist nur durch die Pressoreceptoren über den Blutdruckanstieg ausgelöst. Eine hemmende Wirkung von Adrenalin auf das periphere sympathische Schaltganglion konnte nicht nachgewiesen werden. Die sympathische Antwortreaktion bei Reizung spinaler Afferenzen wird durch Adrenalin ebenfalls nicht direkt, sondern nur über die Pressoreceptoren beeinflußt. Die gewonnenen Ergebnisse machen es wahrscheinlich, daß außer den bekannten pressosensiblen Strukturen noch andere, uns unbekannte vorhanden sind.

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Summary Adrenaline does not directly inhibit the sympathetic tonus in anaesthetised cats. The inhibition of the sympathetic action potentials after injection of adrenaline is brought about only by the pressoreceptors after an increase in blood pressure. An inhibitory action of adrenaline on the peripheral sympathetic ganglion does not occur. The sympathetic response after stimulation of afferent spinal nerves is not influenced directly by adrenaline but only via pressoreceptors. The results make it seem possible that in addition to the known pressosensible structures other unknown pressosensible structures exist.

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Mit 5 Textabbildungen

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Industrial aerosols are a risk factor of oncologic diseases in underground miners

The paper contains new data on the carcinogenicity of industrial aerosol to miners engaged to underground extraction of sulphide copper and nickel ores. Earlier appearance of oncologic diseases (lung and stomach cancer) is typical of this category of workers, exposed to higher aerogenic concentration of nickel in mine atmosphere. This fact demonstrates that the leading role in the ethiology of these diseases is played by multicomponent industrial aerosol containing nickel in the form of complex sulphides.     

Detection of thrombotic vascular lesions by MR tomography

Magnetic resonance tomography (MRT) was used to investigate 54 patients with a variety of vascular lesions; 38 of those had essential hypertension, including malignant arterial hypertension in 9. Sixteen patients had vascular arterial hypertension, with thrombosis-complicated vascular lesions: unilateral renal artery thrombosis was detected in 6, aortic aneurysm with perimural thrombosis, in 5, Leriche's syndrome, in 3, and unilateral iliac artery thrombosis, in 2. Twenty seven normal subjects, investigated by radionuclide angiography, were taken as controls. Hypertensive patients showed aortic convolution, thickened aortic wall and a certain irregularity of signals inside the aortic lumen, an evidence of possible perimural thrombosis as well as turbulent currents. These data coincided with ultrasonic, computerized tomographic and angiographic findings. In patients with unilateral renal arterial thrombosis, an area of prostenotic dilatation or the thrombosed renal artery itself could be clearly seen. In patients with Leriche's syndrome, thrombosed iliac artery was better visualized because of a greater vascular diameter. In patients with aortic aneurysm, aneurysmal bag, with impulses of different intensity inside the lumen and blurred outline, could be clearly seen. It is concluded that MRT can be used for the diagnosis of vascular thrombotic lesions.     

Activity of peripheral sympathetic efferent nerves in experimental subarachnoid haemorrhage

Summary The origin and pathomechanism of vegetative disturbances in patients suffering from subarachnoid haemorrhage are not completely clarified. Since some of these alterations in vegetative functions may well be attributed to acute changes in sympathetic activity, we initiated a study to investigate this modality in experimentally induced subarachnoid haemorrhage. Experiments were performed on 51 cats, anaesthetized with alpha-chloralose and urethane, immobilized and artificially ventilated. Compound electrical discharges of the left vertebral, cardiac and renal sympathetic nerves, ECG, EEG, end-tidal CO 2, systemic arterial blood pressure and intracranial pressure were recorded on a polygraph. Subarachnoid haemorrhage was simulated by the injection of 1–5 ml of fresh, autologous blood into the cisterna magna. Mock cerebrospinal fluid was also injected as a control.Our results showed that in induced subarachnoid haemorrhage, not the blood itself but the intracranial pressure elevation might be responsible for the strong increase in sympathetic efferent activity. With the direct recording of the electrical activity of the three sympathetic nerves, we were able to verify the sympathetic overactivity underlying the cardiovascular disturbances during intracranial pressure elevation. Regarding the mechanism of the overactivity, most probably not the ischaemia or hypoxia, but the mechanical distortion of the medulla could be the adequate stimulus of the sympathetic overactivity and the Cushing response during intracranial pressure elevation.This work was supported in part by the Hungarian Medical Research Council.