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Biomedical subjects

G Csécsei

Publications and source records attributed to G Csécsei.

17 recordsLinked to original sources
PubMed2006

Nitric oxide production in striatum and pallidum of cirrhotic rats.

Ammonium and manganese are neurotoxic agents related to brain metabolic disturbances observed after prolonged liver damage. The aim of this study was to assess the production of nitric oxide (NO) in the brain of cirrhotic rats exposed to manganese. We induced cirrhosis by bile duct ligation for 4 weeks in rats. From brain, striatum and globus pallidus were dissected out, and NO synthase activity and the content of nitrites plus nitrates (NOx) were determined. In pallidum we found a diminished constitutive NO synthase activity from cirrhotic rats, independently of manganese exposure. This result was confirmed by low levels of NOx in the same brain area (P<0.05, two-way ANOVA). This finding was not related to protein expression of NO synthase since no differences were observed in immunoblot signals between cirrhotic and sham-operated animals. Results from present study suggest that the production of NO is reduced in basal ganglia during cirrhosis.

Animals↗
PubMed2005

Quantitative determination of hyaluronan content in cerebral aneurysms by digital densitometry.

OBJECT: Hyaluronan (HA) is a highly hydrated macromolecule; it is one of the essential components of the extracellular matrix (ECM) of the arteries and plays an important role in maintaining the biomechanical features of blood vessels. Although the potential contribution of HA in aneurysms of different vessels has been studied intensively, no data are available about the alteration of the HA content in the extracellular matrix of intracranial aneurysms. The aim of the study was to determine the hyaluronan content in the wall of human cerebral arteries. METHODS: A biotinylated aggrecan fragment that binds specifically to HA was used to stain samples from cerebral aneurysms (n = 11) to compare the HA content to non-aneurysmal arteries of patients who had intracranial aneurysm (n = 11), and to histologically normal arteries of patients who had expired from non-vascular diseases (n = 14). Digital microscopic densitometry was used for the quantitative analysis of the hyaluronan content in these samples. RESULTS: The highest level (169.5 +/- 7.9) was detected in aneurysms, while the HA-level of non-aneurysmal vessels was lower (130.2 +/- 16.8). Both vessel groups contained significantly higher HA than the normal cerebral arteries (32.9 +/- 2.1). CONCLUSIONS: Results suggest that an elevated hyaluronan level in the extracellular matrix may affect the cerebral arterial wall architecture. It is reasonable to suppose that the increased hyaluronan content creates a viscoelastic ECM which might improve the biomechanical resistance of the thinned vessel wall.

Adult↗
PubMed2001

Multiple binding sites for melatonin on Kv1.3.

Melatonin is a small amino acid derivative hormone of the pineal gland. Melatonin quickly and reversibly blocked Kv1.3 channels, the predominant voltage-gated potassium channel in human T-lymphocytes, acting from the extracellular side. The block did not show state or voltage dependence and was associated with an increased inactivation rate of the current. A half-blocking concentration of 1.5 mM was obtained from the reduction of the peak current. We explored several models to describe the stoichiometry of melatonin-Kv1.3 interaction considering one or four independent binding sites per channel. The model in which the occupancy of one of four binding sites by melatonin is sufficient to block the channels gives the best fit to the dose-response relationship, although all four binding sites can be occupied by the drug. The dissociation constant for the individual binding sites is 8.11 mM. Parallel application of charybdotoxin and melatonin showed that both compounds can simultaneously bind to the channels, thereby localizing the melatonin binding site out of the pore region. However, binding of tetraethylammonium to its receptor decreases the melatonin affinity, and vice versa. Thus, the occupancy of the two separate receptor sites allosterically modulates each other.

Antibodies, Monoclonal↗
PubMed1997

Posterior lumbar interbody fusion (PLIF) using the bony elements of the dorsal spinal segment.

Many different types of surgical technics for treating unstable degenerative spondylolisthesis of the lumbar spine has been reported. The most important part of the different procedures is to achieve a solid bony fusion between the two vertebrae. Authors report a new simple method of posterior lumbar interbody fusion in spondylolisthesis. The whole posterior segment of the mobile neural arch is removed and used for fusion. Corticospongiosus dowels and small bone chips are impacted into the disc space emptied totally before. Monosegmental transpedicular fixateur is required for stability. 33 patients with an average follow up of 20 months showed a clinical improvement of 88%. The radiologically proved fusion rate was 90%. Authors achieved good clinical outcome and high bony fusion rate with the one stage operation from posterior approach for treating lumbar spondylolisthesis.

Bone Screws↗
PubMed1996

Fibrin deposition in primary and metastatic human brain tumours.

Extravascular, intratumoral fibrin deposition is frequently observed within and around neoplastic tissue and has been implicated in various aspects of tumour growth. This is the first report on the presence and distribution of fibrinogen/fibrin in primary (14 glioblastomas) and metastatic (nine samples of lung cancer origin) human brain tumours detected by immunofluorescent techniques. All tissue samples showed specific staining for fibrinogen/fibrin. In glioblastomas fibrin deposits could be detected within and around tumour foci, while in metastatic brain tumours the tumour cell nodules were surrounded by fibrin deposits localized almost exclusively in the connective tissue compartment of tumours. Double-labelling reactions for von Willebrand factor and fibrinogen/fibrin has revealed that fibrin deposition occurred throughout the tumour stroma independently of tumour vasculature. The overlapping reactions for fibrinogen/fibrin and factor XIII subunit A, as well as the urea-insolubility of the deposits indicate the crosslinked, highly stabilized nature of fibrin both within and around tumours. Staining with Ki M7 monoclonal antibody specific for phagocytosing macrophages showed these cells to be scattered in the nonnecrotic areas in glioblastomas and to be accumulated at the interface of tumorous parenchyma and connective tissue in both primary and metastatic tumours. The close association between fibrin deposition and macrophage accumulation strongly suggests the active participation of tumour associated macrophages in the formation of stabilized intratumoral fibrin network in human brain neoplasms.

Blood Coagulation↗
PubMed1996

Examinations of the motor conduction time between the motor cortex and the Erb point in patients suffering from tumors of the central nervous system.

The cortical latency and the motor conduction time between the motor cortex and the Erb point were investigated in 85 patients with intracranial and in 9 patients with space-occupying spinal tumors. Electrophysiological examinations revealed pathological changes in 19% of intracranial events, and in 100% of cases of spinal tumors. In these latter cases close correlation was registered between the motor evoked potentials and the clinical symptoms of the patients.

Adult↗
PubMed1988

[Intraoperative monitoring with visual and auditory evoked potentials].

Intraoperative monitoring techniques concerning evoked potentials have been used during operations on the spinal cord as well as in carotid endarterectomy and in aneurysm surgery. The monitoring of early acoustic evoked potentials during surgery of the posterior fossa and the registration of the visually evoked potentials in patients suffering from pituitary adenoma or other space occupying lesions of the sella region seem to provide information about function of nerves and brain stem structures. This paper deals with positive and negative aspects of intraoperative monitoring of visual and acoustic evoked potentials.

Brain Neoplasms↗
PubMed1987

Electrically elicited blink reflex and early acoustic evoked potentials in circumscribed and diffuse brain stem lesions.

In the present paper, the function of the brain stem in patients with brain stem lesions of various aetiology is investigated with electrophysiological methods. The clinical observations are supplemented by experimental investigations on cats, in which the blink reflex and the early acoustic evoked potentials were registered during the acute elevation of intracranial pressure. The findings in patients with circumscribed space-occupying lesions in the posterior fossa document that the registration of the BR and the BAEP have a functional diagnostic significance above and beyond the neurological and radiological investigation. In the case of the cerebellar space occupations, specific alterations could not be observed. On the contrary, the alterations of BR and BAEP indicate a general disturbance of brain stem function, possibly as a result of a general increase of intracranial pressure. In cerebellopontine angle tumours, both BR and BAEP showed specific alterations which were usually asymmetrical. The BR changes ipsilateral to the tumour are of major topodiagnostic significance, whereas the alterations of the contralateral potential are especially informative in the registration of BAEP. The alterations of BR and BAEP also allow an appraisal of the localization and extent of the lesion in primary space occupations in the brain stem: A pathological R1 indicates a pontine lesion, whereas pathological R2 responses are found in medullary and in oral pontine and mesencephalic lesions. In contrast to cerebellopontine angle tumours, the BAEP tends to show symmetrical alterations in primary brain stem lesions. The prolongations of interpeak latencies correspond to the brain stem segment concerned, and the same also applies to pathological amplitude reduction and deformations of individual potentials. In patients with localized brain stem damage, the reflex pathway of R2 is discussed on the basis of the BR findings. In contrast to the view held up to now that only structures situated caudal of the facial nucleus area are responsible for the genesis of the R2 response, it is assumed on the basis of our own observations that pontomesencephalic structures rostral to the facial nuclei are also important for the genesis of R2. Registration of BR and BAEP in patients with acute diffuse brain stem damage shows that both methods have a high diagnostic and prognostic value. Isolated damage and combined brain stem lesion can be demonstrated and the course can be followed up. Normalization of pathological findings reflects clinical recovery, and conversely a secondary deterioration indicates the presence of complications.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1983

Effect of increased intracranial pressure on the blink reflex in cats.

During an acute increase in ICP produced by balloon inflation three different phases could be observed. In the first phase (ICP 40-50 mm Hg) the latencies of R 1 and R 2 showed an initial decrease followed by increase in latency. In the second phase (ICP 50-70 mm Hg) R 2 disappeared, whereas R 1 showed marked alterations, prolongation of the latency and duration, and a decreasing amplitude. In the third phase no response could be evoked. The pathophysiological observations correlated with the morphological alterations. Two ischaemic zones with BBB damage which "transsected" the mesodiencephalic and pontomesencephalic border were found. The results suggest that the disappearance of R 2 depends on rostral damage, whereas alteration of R 1 is caused by a pontomesencephalic lesion.

Animals↗
PubMed1975

[Experiences with oto-rhinogenous brain abscesses (author's transl)].

The results and conclusions of 43 surgical interventions performed on account of oto-rhinogenous brain abscess are reported. In these patients the infection of brain substance occurred in two ways: 1 by contact propagation and 2. per venous reflux, associated with thrombosinusitis. In the 1. the brain abscess was accompanied by purulent meningitis and the majority of the patients died during the postoperative period. In the 2, the patients operated on account of cerebral abscess developed per venous reflux, improved and became health. In order to get more exact localisation of the abscess there are different radiological auxiliary methods available: in supratentorial abscesses exact informations can be obtained by carotid angiography, while in the cases of infratentorial abscesses the pneumography is helpful, notwithstanding the latter is not fully harmless. As the ideal operative solution the total exstirpation of the abscess with undamaged capsule can be proposed.

Adolescent↗