Biomedical subjects

Z Mariak

Publications and source records attributed to Z Mariak.

At least 73 records · Page 4Linked to original sources

PubMed1980

[Rheoencephalographic studies in a group of 102 healthy persons].

Rheoencephalographic (REG) investigations were carried out in a group of 44 women and 58 men aged from 18 to 67 years. It was found that the amplitude of REG waves on the group of women was significantly smaller than in men. A characteristic tendency was observed with progressing age of the subjects for a decrease of the amplitude of REG waves with prolongation of the duration of the ascending arm of the wave and with an increase in the value of the dicrotic index, as well as a decrease in the value of the angle of inclination of this ascending arm to the base. Atherosclerosis of the cerebral vessels was a factor contributing significantly to progression of these changes. On the basis of visual analysis three main types of REG waves were isolated which corresponded to successive phases of elasticity loss of brain vessel walls. The authors suggest accepting the value of 10--90 centile of the determined values of REG wave parameters as the range of normal values for different age groups and the type of REG apparatus used.

Adolescent↗

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Transcranial color Doppler sonography in the emergency diagnosis of middle cerebral artery occlusion in a patient after head injury.

The purpose of this report is to highlight the utility of transcranial color Doppler sonography (TCCDS) in the emergency diagnosis of an ischemic stroke in a 64-year-old patient after head injury. An emergency CT identified a subdural hematoma, subarachnoid hemorrhage, a brain contusion and edema. The patient's status deteriorated after admission, and a second CT revealed an intracerebral hematoma and marked mass effect. Transcranial color sonography revealed no flow in the ipsilateral middle and anterior cerebral arteries, which was consistent with ischemic stroke. This case demonstrates that transcranial color Doppler sonography performed early after head injury may be useful in detecting associated occlusion of cerebral vessels.

Arterial Occlusive Diseases↗

PubMedDate not supplied

Limitations of color Doppler sonography in the imaging of ocular vessels.

PURPOSE: To describe a case where detection of blood flow in the central retinal artery and the central retinal vein was limited by an artifact evoked by the optic disc drusen. METHODS Case report. RESULTS: During color Doppler sonography, examination of optic disc drusen may generate an artifact--the so-called twinkling artifact--which can simulate blood flow and make evaluation of the central retinal vessels impossible. CONCLUSIONS: Twinkling artifact does not allow evaluation of color Doppler sonography in the imaging of ocular vessels.

Artifacts↗

PubMedDate not supplied

Risk factors of massive suprachoroidal hemorrhage during extracapsular cataract extraction surgery.

PURPOSE: To estimate retrospectively the incidence, predisposing factors, and possible mechanisms precipitating massive suprachoroidal hemorrhage (MSCH) development during cataract extraction surgery. METHODS: The study was conducted on 6639 consecutive cataract extractions performed between 1994 and 2002. All of the procedures were carried out using traditional nucleus expression methods. The study cases comprised 19 patients who developed intraoperative MSCH. The remaining 6620 patients served as the control group. Baseline systemic and ocular characteristics, as well as intraoperative factors, were analyzed. Categorical variables were analyzed using the chi-square test and the Fisher exact test. RESULTS: The incidence of MSCH during cataract surgery was 0.28%. Highly significant risk factors included high myopia, glaucoma, and diabetes (p<0.01). Atherosclerotic vascular diseases and/or hypertension were less significantly related to the condition (p<0.05). There was no significant relationship between MSCH formation and age, sex, side of the cataract, history of ocular trauma, or inflammation. The incidence of MSCH did not differ between patients operated on with extracapsular or intracapsular cataract extraction. CONCLUSIONS: Attention to multiple preoperative and intraoperative ocular and systemic variables may allow the identification of, and prophylaxis for, patients at greater risk for MSCH.

Adult↗

PubMedDate not supplied

Pathogenesis of primary internal ophthalmoplegia after head injury.

Primary internal ophthalmoplegia is a rare ocular syndrome after head injury. Its pathogenesis remains unclear and it is only a hypothesis that the pupillomotor fibres on the ventromedial aspect of the oculomotor nerve are slightly contused against the petroclinoid ligament at the moment of impact. We observed a patient after head injury who presented with a fixed, dilated pupil and died within 15 hours of the accident. The postmortem examination revealed an isolated group of fibres on the medial aspect of her oculomotor nerve, which had been torn out of the midbrain. This suggests an alternative explanation in terms of partial injury to the oculomotor nerve to account for primary internal ophthalmoplegia.

Accidents, Traffic↗

PubMedDate not supplied

Cranial nerve II-VII injuries in fatal closed head trauma.

PURPOSE: To study the distribution and mechanism of traumatic injuries to the nerves supplying the eye and muscles protecting the visual apparatus. METHODS: Brain autopsy was carried out in 12 consecutive patients who died within three days after closed head injury. A segment of the brainstem with the entire intracranial portion of nerves II-VII was dissected out in each case and fixed in formalin. The specimens were stripped of the leptomeninges and inspected thoroughly under magnification. RESULTS: Injuries to the nerves were seen in nine subjects. The oculomotor nerve was completely torn off from the midbrain unilaterally in three and bilaterally in two cases. In one patient only a portion of the superficial fibres on the medial aspect of the nerve was ripped out from the brainstem. In two patients the fourth nerve was ruptured. The root of the fifth cranial nerve was contused and the fibres between the brainstem and Gasserian ganglion crushed and separated in one case. Bilateral avulsion of the root of the sixth nerve from the brainstem was found in two cases. The initial segment of the facial nerve was crushed in two subjects. No visible injury to the optic nerves was found. CONCLUSIONS: Cranial nerves related to the visual system are subject to serious injury in a large proportion of cases of severe head trauma resulting from automobile accidents. In the majority of cases damage results from ripping the roots of these nerves out of the brainstem.

Accessory Nerve Injuries↗

PubMedDate not supplied

[Proliferative activity of glial neoplasms of the brain].

The aim of the study including 89 brain gliomas was to determine their proliferative activity assayed with immunohistochemical methods (PCNA and Ki-67) and with the method of AgNORs, as well as to evaluate the correlation between the proliferative activity and features of histological malignancy. The study reveals that the estimation of PCNA, Ki-67 and AgNORs are effective methods for the determination of the proliferative activity of brain gliomas. Statistically significant differences were noted in the proliferative PCNA, Ki-67 and AgNORs between groups of gliomas with lower and higher malignancy, which indicated a distinct correlation between histological malignancy of the tumours and their proliferative activity. High values of PCNA and Ki-67 (> 40%) and AgNORs (> 15) were found to considerably deteriorate prognosis in brain gliomas.

Adult↗

PubMedDate not supplied

[Remote results of conservative treatment of traumatic optic neuropathy].

The problem of pathogenesis and effective treatment of traumatic optic neuropathy (TON) is still an open question. According to current opinions the immediate results of conservative treatment with megadose corticosteroids are similar to those obtained with surgical decompression. No data on late results of both modes of treatment are at present available. This study was undertaken to assess the late results of conservative treatment of traumatic optic neuropathy. The clinical material comprised 15 patients (3 women and 12 men, age 14-64 years), who developed clinical symptoms of TON as a consequence of closed head trauma. All were treated conservatively with megadose steroid therapy. 10 patients presented to follow-up examination performed 3-11 years after the injury. A full ophthalmologic survey and colour-coded Doppler (CCD) examination of the orbital vessels were performed in all subjects. In 6 patients there was full blindness of the affected eye since the injury. Their visual acuity did not improve despite vigorous treatment and their eyes were still blind at the late follow-up examination. No flow found with CCD in their central retinal arteries at follow-up might suggest structural disruption of the nerve. In 5 of these patients ocular atrophy evolved between the injury and follow-up examination. 4 patients, who on admission displayed merely light sensation, responded to 2-3 weeks of steroid therapy with improvement of visual acuity to 3/50, 5/50, 5/10, 5/7. After 4-6 years however, visual acuity of all these patients deteriorated again to mere light perception in three and 1/50 in another one. Optic atrophy was diagnosed in all the affected eyes. Our results indicate that conservative treatment of TON, even if giving satisfactory relief of the symptoms, may not be reliable in permanent restrainment of the sequela of traumatic optic neuropathy.

Adolescent↗

PubMedDate not supplied

[How does the immune system communicate with the brain?].

It is now evident, that the immune system and the central nervous system (CNS) are functionally connected and interact with one another. The entrance of pathogenic micro-organisms or their products into the body evokes an array of systemic responses, i.e. acute-phase proteinemia, neutrophilic leucocytosis, changes in the circulating levels of various hormones, and fever with specific changes of behaviour. It is now generally recognised that many of these responses are modulated by the brain. Until 1995 it was thought that the transport of immune signals to the brain is mediated by a humoral mechanism, mainly by certain cytokines, produced by activated monocytes and macrophages. The mechanism for the transfer of cytokines through the blood-brain barrier was however not completely understood until recently. It was also not clear, how the fast febrile phase can be signalled within 15 min, if the sequence: external pyrogen-->monocytes-->cytokines-->prostaglandins-->stimulation of the hypothalamus-->fever, requires 40-60 minutes to be activated. In addition to the "classical" humoral mode of transfer, it has recently been proposed that the immune signals are transported to the brain by certain peripheral nerves, predominantly by the vagus. The macrophages of the liver (Kupfer cells) start producing small amounts of cytokines in response to their activation by bacterial lipopolisaccharides, coupled into a complex with the already pre-activated anaphylatoxic component of the complement. These cytokines can immediately activate adjacent sensory paraganglia of the hepatic vagus nerve, which carries these stimuli to the nucleus tractus solitarius, which in turn sends them out to the hypothalamus via the ascending noradrenergic pathways. This fast avenue of communication between the immune system and the brain is activated not only in pathological situations, corresponding to fever, but is an important component of systemic homeostasis, e.g. regulation of body temperature.

Brain↗

PubMedDate not supplied

[Brain temperature during craniotomy in general anesthesia].

Mild hypothermia may occur spontaneously or, because of its putative neuroprotective effect, may be induced purposefully during neurosurgical procedures. Though the brain is the organ targeted for the purpose of neuroprotection, little is known about its temperature during general anaesthesia and craniotomy. The purpose of this study was to define the relations between core, skin and brain temperature during craniotomy and to compare two modes of inducing thermal insulation in patients during operative procedures. To achieve this we recorded core: rectal (Tre), oesophageal (Tes) and tympanic (Try) temperature, brain temperature in the subdural space (Tsd), and skin temperature on the thigh (Tfe), forehead (Tfr) and sternum (Tst) in 15 patients undergoing standard procedure for aneurysm clipping. In 13 patients the core temperature decreased, whereas skin temperature increased, after induction of general anaesthesia with isofluran. Nevertheless the mean body temperature remained unchanged, thus supporting the view that the cause of the resultant core hypothermia was heat redistribution between the thermal core and the periphery. Special thermofoil proved to be only as effective as a plain cotton blanket in preventing further heat loss during the later phases of the operation. Brain temperature was found to be the lowest core temperature throughout the procedure. It differed by as much as 0.1-1.2 degrees C from rectal temperature (mean 0.75 +/- 0.41 degree C) and reached the level of mild hypothermia (below 35 degrees C) even in those patients in whom rectal temperature indicated the state of normothermia. Furthermore tympanic and oesophageal temperature was on average 0.5 degree C higher than brain temperature. In conclusion, temperature measurements obtained in standard sites do not reflect brain temperature reliably during craniotomy and general anaesthesia. This indicates that the direct measurement of intracranial temperature is necessary for correct estimation of brain hypothermia.

Anesthesia, General↗

PubMedDate not supplied

[Correlation of steroid receptors and growth factors expression with peritumoral edema accompanying cerebral neoplasms].

The aetiology of peritumoral brain oedema still remains unclear, despite investigations, attempted to study the role of various clinical factors and histological features of the tumour. The aim of this investigation was to the evaluate correlation of peritumoral brain oedema with expression of progesterone (PR) and oestrogen (ER) receptors and vascular--endothelial growth factor (VEGF). Eighty nine samples of brain tumours were examined, among them 28 meningiomas, 43 gliomas and 18 metastatic tumours. Expression of steroid receptors was examined with the radioreceptor assay method and expression of VEGF by radioimmune assay. A statistically highly significant correlation was found of VEGF expression with the incidence of diffuse pattern of brain oedema around gliomas and metastatic tumours (p < 0.01). PR expression was associated significantly with the occurrence of localized type of oedema around meningiomas, but in gliomas the expression of this receptor correlated with a diffuse pattern of oedema. No correlation was found between ER expression and peritumoral brain oedema.

Brain Edema↗

PubMedDate not supplied

[Brain temperature in patients with central nervous system lesions].

The knowledge of human brain temperature is still very limited. In this report we investigated the relationship between brain and trunk temperature in neurosurgical patients during normothermia and fever. Another problem addressed was that of possible gradients of temperature within the brain. We carried out direct recordings of temperature in 63 operated, neurosurgical patients with a variety of intracranial pathologies. Flexible, teflon-coated thermocouples were placed intracranially during neurosurgical procedures. Oesophageal, rectal and tympanic temperatures were also monitored. An error of up to 1.3 degrees C is to be expected in single cases if brain temperature is deduced from the rectal or oesophageal temperature. Mean differences between brain temperature and core body temperature measured in the rectum or in the oesophagus, were between 0 to 0.3 degree C. Tympanic temperature (Tty) improved the approximation of brain temperature (Tbr) to within the mean difference between Tbr-Tty close to 0 degree C. Nevertheless Tty also differed from Tbr by as much as 1 degree C in single cases. Brain temperature was the highest body temperature measured, either in normothermia or in fever. Temperature gradients were proved to exist between the warmer brain interior and cooler surface, with maximal differences in temperature reaching 0.6 degree C. This temperature gradient tended to increase along with the rise in intracranial pressure and deterioration of the level of consciousness. Our results suggest that conclusions regarding brain temperature drawn on the basis of other core temperatures, may lead to significant errors, and intracranial temperature measurement is desirable in neurosurgical intensive care. Temperature gradients within the brain may exacerbate its biochemical injury during ischaemia and fever--a combination seen frequently in neurosurgical patients. This may be particularly so, since brain temperature in fever is the highest body temperature in a high proportion of these patients.

Adult↗

PubMedDate not supplied

[Transcranial color Doppler estimation of blood flow parameters in respective basal cerebral arteries in healthy subjects].

Transcranial colour-coded Doppler sonography enables estimation of blood flow parameters in the basal cerebral arteries. Reference values as well as age and gender dependence of these parameters are not sufficiently established in transcranial Doppler studies. There are no reports regarding blood flow in the respective arteries of the circle of Willis. Therefore we examined 185 healthy volunteers--82 men (mean age 47, range 20-78 years old) and 103 women (mean age 47, range 22-86 years old). The subjects were divided into three age groups: 20-40 years old (group I), 41-60 years old (group II) and more than 60 years old (group III). The examinations were performed via the temporal acoustic window with a 2.5 MHz probe. Angle-corrected peak systolic, mean and end-diastolic velocities as well as impedance indices were determined in the anterior, middle and posterior cerebral arteries. In the group I mean velocity values (mean +/- SD) for the anterior, middle and posterior arteries amounted to 56 +/- 14 cm/s, 81 +/- 20 cm/s and 52 +/- 12 cm/s, respectively. In group II the values were 53 +/- 16 cm/s, 73 +/- 19 cm/s and 51 +/- 12 cm/s, and in group III the values were 44 +/- 11 cm/s, 59 +/- 11 cm/s and 40 +/- 9 cm/s. Decline in the blood flow velocities and increase in the impedance indices were found in all vessels with advancing age. This was most pronounced in subjects who were more than 40 years old. The decrease with age in blood flow velocities was more substantial in the middle cerebral arteries than in the anterior and posterior cerebral arteries. In contrast, the impedance indices increased more distinctly in the anterior cerebral arteries than in the middle and posterior cerebral arteries. We have demonstrated that the blood flow Doppler parameters are age and, in the group I (20-40 years old), also gender dependent. The range of the normal reference values of these parameters has proved to be wide. Decrease with age in blood flow velocities was found to be varied in the major cerebral arteries.

Adult↗

PubMedDate not supplied

[Epidermal growth factor expression in brain neoplasms].

Epidermal growth factor (EGF) influences the cell by activation of its specific cell receptor (EGFR). It is regarded as one of the most effective mitogenic factors and plays a role in carcinogenesis. The aim of this study was the assessment of EGF expression in different types of cerebral neoplasms and searching for its correlation with histopathologic features of malignancy and presence of peritumoral oedema. Sixty seven samples of brain tumours were examined. Among them were 17 meningiomas, 34 gliomas and 16 metastases. Expression of EGF was estimated by a radioimmune assay. The authors found the presence of EGF in all types of tumours. No correlation was found between expression of EGF and histopathological signs of tumour malignancy, although a tendency appeared towards a higher level of that factor in anaplastic tumours. Also, no correlation was found between EGF and peritumoral oedema.

Brain Neoplasms↗

PubMedDate not supplied

[Analysis of intracranial pressure signals using artificial neural networks].

Intracranial pressure (ICP) is influenced by an array of predictable and unpredictable factors. Statistical modelling of this signal has only limited applicability because of the significant load of stochastic components. We tested the efficiency of an alternative approach, based on the methodology of artificial neural networks (ANNs) in the on-line prediction of future values of ICP and in the classification of signal properties. Satisfactory accuracy of forecasting was achieved with the ANNs for a 3-minute prediction horizon, while the prediction quality with autoregressive models of statistical origin was proved unsatisfactory. The results obtained with the ANNs were further improved when signal pre-processing with wavelet transform was employed. Nevertheless, even with the ANN methodology, no sudden breakdowns in the ICP signal (which in this respect might be compared to a "catastrophe") can be forecast with any practical applicability. We therefore applied two ANN algorithms, oriented at classification and discrimination of the global properties of the ICP signal. The neural network was expected to discriminate those sets of signal properties, which were assumed to correspond to certain clinical conditions of the patient. In a "dynamic pattern classification" the network was presented with several sections of ICP records. This was combined with information about the assignment of a given record to one of four arbitrary classes of danger. In this mode no data pre-processing was carried out, in contrast to our second approach, in which the signal was pre-processed with statistical analyses and only these intermediate coefficients were fed to the ANN classifier. The results obtained with both classification methods at their present stage of training were similar and approximated to a 70% rate of judgements consistent with expert scoring. Nevertheless, the method based on the assessment of global parameters of the ICP record seems more promising, because it leaves the possibility of extending the set of training data by information from other diagnostic modalities. The study aims towards the development of a pseudo-intelligent computer expert system, which has would be taught salient links between data extracted from the ICP signal and higher- order data, which contributed to the expert score. Hence the system would be able to make decisions on the basis of a reduced set of input information, available from a standard monitoring modality.

Algorithms↗

PubMedDate not supplied

Brain abscess as a rare complication in a hemodialysed patient.

BACKGROUND: Infections remain among the most common morbid events and are an important cause of death in end stage renal disease. They have reduced immune response and increased hazard of infections due to repeated puncture of an arterio-venous fistula, formation of haematoma at the site of cannulation and central vein catheterisation. CASE REPORT: We report a case of brain abscess in chronically haemodialysed patient admitted to our department due to haedache, vomiting, accelerated hypertension and fever. The clinical examination revealed narroving of the right palpebral slit, weeping and right oral angle hanging loose. He had mild microcytic anaemia and high level of g-globulin. Ophtalmologic examination showed normal oculi fundi. The computed tomography revealed heterogenous mass marginally enhanced with contrast agent in the right frontal cerebral lobe. The right fronto-temporal craniotomy was performed and the right frontal lobe abscess was found and totally excised. The postoperative course was uneventful besides of seizures which were effectively treated with carbamazepine. After bilateral nephrectomy the patient undervent succesfull kidney transplantation and is in good condition without any neurological defect. A probable cause of his brain abscess was peridontal abscess recognized 3 month earlier or bilateral vesicoureteral refluxes. CONCLUSIONS: 1. Uremic patients have a reduced immunocapacity and are a high risk group for infections of various etiology. 2. Prompt eradication of all sources of infection is essential in hemodialysed patients.

Adult↗

PubMedDate not supplied

[Vascular endothelial growth factor expression in cerebral neoplasms].

Angiogenesis plays an important role in growth of neoplasm. Among a variety of proangiogenic agents, vascular endothelial growth factor (VEGF) is regarded as a crucial mediator of tumour angiogenesis. It acts in a paracrine way through the receptors localised in endothelial cells. Many authors maintain that rich vasculature of the neoplasm is associated with its malignant nature. The aim of this study was to examine the relations between expression of VEGF and features of malignancy of brain tumours. Sixty-seven samples of brain tumours were examined: 17 meningiomas, 34 gliomas and 16 metastases to the central nervous system. Expression of VEGF was estimated by radioimmune assay. The authors confirmed the presence of this factor in all types of tumours but the highest concentration of VEGF was found in high-grade gliomas.

Brain Neoplasms↗

PubMedDate not supplied

[Internal ophthalmoplegia as a direct consequence of head injury. Report on 2 cases].

The authors describe two cases admitted following head injury and presenting with a dilated, stiff pupil. CT scan of the head revealed no intracranial mass lesion. The symptoms persisted over a year in one case, whereas in the other one they faded away within a few weeks. The symptoms are believed to arise due to a downward shift of the brainstem which is known to occur at the moment of head injury. The oculomotor nerve is ++over-stretched and is supposed to be partially damaged at the posterior petroclinoid ligament. The roots of the pupillomotor fibers may also be supposedly torn at the site where they leave the brainstem.

Adult↗