Biomedical subjects

J Lewko

Publications and source records attributed to J Lewko.

At least 19 recordsLinked to original sources

PubMed2005

Detection and monitoring of cerebral hemodynamic disturbances with transcranial color-coded duplex sonography in patients after head injury.

Reduced cerebral blood flow after severe head injury results in an increased risk of ischemic brain damage. Blood flow should therefore be monitored with a simple, reliable method. Transcranial color-coded Doppler sonography (TCCS) is an accepted tool for the diagnosis of cerebral vasospasm; however, its usefulness in evaluating patients with head injury has not been proven. Cerebral blood-flow velocity in the middle, anterior, and posterior cerebral arteries was measured with a 2.5 MHz probe (Aplio SSA 770A, Toshiba, Japan) in 36 subjects with moderate or severe head injury. Serial measurements of resistance index (RI), peak-systolic, end-diastolic, and mean velocity in the middle cerebral arteries were performed 2-24 h after head trauma and in the subsequent days during hospitalization. Immediately after head trauma, increased RI values, and unusually decreased blood-flow velocity (mainly in MCA) were observed. Microcirculation disturbances were suspected because the end-diastolic velocity had substantially diminished. Changes in blood-flow parameters correlated with the clinical state, and in most cases, a poor prognosis. In some patients, blood-flow velocity increased above the normal reference limit and this implied poor prognosis. Transcranial color-coded Doppler sonography is a reliable, repeatable, and accessible tool that provides information about cerebral blood-flow disturbances and may hold diagnostic and prognostic importance.

Blood Flow Velocity↗

PubMed2005

The education of patients with rheumatoid arthritis--the knowledge and expectation of patients-the opinions of rheumatology nurses.

Rheumatoid arthritis (RA) is a chronic, progressive, immunologically dependent, systemic diseases of connective tissue, leading to disability, cripplehood or even premature death. Helping to improve the quality of life of RA patients involves teaching them how to cope with disease-related problems of everyday life, with stress and with suffering. The aim of the presented work is to determine the following: the patients' level of knowledge about rheumatoid arthritis; their educational needs; the impact of the level of knowledge on the patients' pro-health behaviours; the knowledge of nurses and their ability to recognize patients' problems; the nurse's tasks in preparing an RA patient for self-care. The subject group consisted of patients with RA diagnosed according to The American Rheumatism Association criteria and nurses from rheumatology clinics and wards. The research method used was a survey questionnaire, which had been constructed for the purpose of the research. The research results indicate a great need of patients, especially those with early rheumatoid arthritis, for education, support and help in adaptation. At the same time, the nurses, even though they do not fully fulfil their educational role, declare a willingness to participate in organized forms of health education.

Arthritis, Rheumatoid↗

PubMed2005

The importance of the health education in life quality improvement in patients with psoriasis.

PURPOSE: The aim of the study was to determine the influence of the psoriatic patient knowledge of the disease on the quality of life. MATERIAL AND METHODS: The study was carried out in 149 patients with psoriasis. All patients answered on anonymous questionnaire, in according to Psoriasis Disability Index (PDI). RESULTS: Almost 43% patients could not show any factor which provoked their disease, 31.5% could not tell any recommendations for cure and care of the psoriatic lesions and 32.2% patients could not point out any methods to avoid psoriatic lesions spread. Almost 60% of the group admitted that their quality of life fell because of the disease. At the same time, patients who did not have enough information concerning the disease had lower quality of life index. CONCLUSIONS: The level of the disease knowledge in the patients with psoriasis influences their quality of live. Therefore it is indicated for the patiens and their families to be involved in the proper educational program.

Adult↗

PubMed2005

Assessment of risk for pressure ulcers using the Norton scale in nursing practice.

PURPOSE: The aim of our study was risk assessment for the development of pressure ulcers and thus defining a group of patients considered to be at risk of developing pressure ulcers. It also helped to define the role of the nurse in the early assessment of the risk for developing pressure ulcers. MATERIAL AND METHODS: Risk assessment for the development of pressure ulcers was carried out in 199 patients hospitalised in The District Hospital in Bielsk Podlaski. The research was carried out with patients admitted to The Departments of General Medicine, Infectious Diseases and Long-Term Care. Risk assessment for the development of pressure ulcers was performed with the aid of the Norton scale. CONCLUSIONS: An increased risk for the development of pressure ulcers was found in more than half of the patients examined (53.8%). Pressure sores developed in 17.6% of the patients, women being at significantly greater risk. Risk assessment for the development of pressure ulcers with the aid of one of the recommended scales facilitates the early recognition of those patients at risk of developing pressure ulcers.

Adult↗

PubMed2003

Tympanic temperature reflects intracranial temperature changes in humans.

The purpose of the study was to identify extracranial locations in which temperature changes in humans reflect those of intracranial temperature in a reliable and repeatable way. This was achieved by subjecting 14 non-anaesthetized patients after neurosurgery to face fanning while intracranial and extracranial temperatures were continuously measured. In all patients the cranium was closed and the group included both febrile and non-febrile as well as hyperthermic and normothermic patients. The patients' faces were fanned for 20-30 min, with a small fan at an air speed of 3.25 m s(-1). This gave intracranial temperature changes measured in the subdural space ( T(sd)) that were highly and significantly correlated ( r=0.91, P<0.05, n=14) with changes in tympanic temperatures ( T(ty)). A low, statistically insignificant correlation ( r=0.40, P>0.05, n=12) was found between T(sd) and oesophageal temperatures. In conclusion, intracranial temperature changes, induced by face fanning, were reliably reflected by the changes in T(ty).

Adult↗

PubMed2003

Oscillations of cerebrovascular resistance throughout the menstrual cycle in healthy women.

OBJECTIVES: Increased concentration of endogenous estrogen during a typical menstrual cycle has been shown to correlate with augmentation of blood flow through the internal carotid arteries (ICAs), which may be related to changes in vascular resistance within the brain. In this study we investigated the effects of endogenous estrogen and progesterone on cerebrovascular impedance in young healthy women. METHODS: The blood flow in the ICA and the common (CCA) and external (ECA) carotid arteries was studied with duplex Doppler sonography. The resistance index (RI) was determined and correlated with plasma 17beta-estradiol concentration in 14 young healthy women throughout their menstrual cycle. RESULTS: The concentration of 17beta-estradiol increased in the follicular phase of the cycle and reached a peak on day 14, whereas concentration of progesterone remained low. Along with an increase in estrogen concentration, the ICA RI had decreased from its initial level on average by 9.2% on day 13 and by 6.7% on day 14 (P < 0.05). In contrast, the trend of the ECA RI was to increase during the peak of estrogen concentration. There were no significant changes in the CCA RI or in the systolic blood pressure, heart rate, hematocrit and hemoglobin concentration through the menstrual cycle. CONCLUSIONS: Estrogen-related augmentation of blood flow through the ICA is caused mainly by decreased cerebrovascular impedance, as shown by a decrease in the ICA RI. These changes in RI suggest that estrogen influences cerebral impedance mainly by altering the resistance of cerebral microvasculature.

Adult↗

PubMed2001

Human brain temperature in vivo: lack of heating during color transcranial Doppler ultrasonography.

This study was undertaken to assess the effect of ultrasound on human brain temperature in vivo. The investigation consisted of direct recording of intracranial temperature during color transcranial Doppler (TCD) sonography in a neurosurgical patient. The temperature was recorded from 3 thermocouples. One was implanted together with an intracranial pressure sensor into a surgically reduced intraparenchymal hematoma, the second was placed within the subdural space close to the temporal acoustic window, and the third was located extracranially at the outer surface of the temporal bone. Tympanic temperatures were also measured to give an approximation of global brain temperature. A 2.5-MHz transducer was used, and the system settings were as follows: spatial peak temporal average intensity = 234 mW/cm2 in B-mode at a maximum power of 32.3 mW and 2132 mW/cm2 in Doppler mode at a maximum power of 149.3 mW. Neither increase in the intraparenchymal brain temperature nor increase in the temperature at the bone/soft tissue interface was observed during 30 minutes of insonation. The ipsilateral tympanic temperature increased by only 0.06 degree C, and this value may be regarded as a measure of the overall increase in brain temperature. Passive cooling effect produced by the transducer, which was at ambient temperature, was found to reach the brain surface and to surpass any possible heating caused by the ultrasound. The results indicate that no noticeable increases in human brain temperature occur in response to ultrasound emitted by a color TCD device at high transmitter power settings within the diagnostic range.

Body Temperature↗

PubMed2001

Effect of endogenous estrogen on blood flow through carotid arteries.

BACKGROUND AND PURPOSE: Recent evidence suggests that physiological changes in the concentration of endogenous estrogens may influence stroke outcome. The purpose of this study was to determine a menstrual cycle-related profile of blood flow through the carotid arteries and its correlation with estrogen concentration. METHODS: The flow velocity and cross-sectional area of the common carotid artery, internal carotid artery (ICA), and external carotid artery (ECA) were measured with duplex Doppler sonography throughout the menstrual cycle in 14 healthy women. Concentration of plasma 17beta-estradiol, progesterone, hematocrit, hemoglobin, and blood pressure were also determined. RESULTS: In the follicular phase, the concentration of estrogen increased to reach a peak on day 14, whereas concentration of progesterone remained low. The mean and end-diastolic velocities in the ICA increased on average by 15% of their base values, along with increasing concentrations of estrogen (r=0.59 and 0.65, respectively). The profile of flow velocity changes in this artery corresponded to the profile of estrogen concentration. In contrast to the ICA, flow velocities in the ECA decreased from their base value, reaching their minimum in the luteal phase. The mean flow velocity in the common carotid artery increased on day 14 by just 2% of its base value. The lumen of the carotid arteries was stable throughout the cycle. Hematocrit, hemoglobin, and systolic blood pressure also remained unchanged. CONCLUSIONS: Increased concentration of endogenous estrogen correlates with substantial augmentation of flow in the internal carotid artery. This promotion of flow is caused mainly by decreased cerebrovascular resistance with consequent "stealing" of blood from the ECA.

Adult↗

PubMed2001

Ergonomics of living environment for the people with special needs.

A safe, convenient, sound and healthy living environment is the prerequisite for a good house for the people with special needs. The intention of making a house in such a way that it solves basic problems of fixture and fittings. However the construction phase of a good house is a critical to design inside and outside structures. Often the builders do not know all the factors to be considered that can maintain a safe, hygienic and healthy environment. It is believed that when housing is ergonomically furnished, then a maximum benefit will be achieved. To meet with an individual's specific needs, an analysis of user's requirement is the most important factors to be considered in the design of special houses. Users' data such as anthropometric dimension, users' choices and preferences are also necessary to design a suitable living environment. In this regard, this paper illustrates some ergonomic features to design and develop good houses in terms of how people with restricted mobility and communication can truly be helped residing in their homes and performing their daily living activities. Users' social, medical and engineering needs are highlighted following the process of disability, ageing, or impairments to achieve the maximum level of benefits, and ensuring safe and sound living.

Activities of Daily Living↗

PubMed2001

HFs/ergonomics of assistive technology.

An assistive device is designed to accommodate the special needs of disability that can help people with physical, mental or cognitive challenges go through their day-to-day activities with less difficulty. An assistive device usually provide alternatives to functional limitations imposed by the client's disorder, and thereby minimising rehabilitation costs. It is therefore important to know about how assistive technology will function in all the possible aspects of such disabilities and impairements. When designing a technical device, particularly in conjunction with the target user group, ergonomic issues are therefore important to find out the extent to which an assistive device is convenient or not, and to check the quality performance of assistive technology. Since the question of the match or mismatch of an assistive device and a disabled person requires much attention, it is therefore suggested that paying attention on how an assistive device be ergonomically designed and developed is important. Ergonomic applications are to be applied for increasing motivation of prospective customers through innovative performance of AT. The authors believe that there are opportunities in ergonomic applications to manufacture an assistive device as unique, cost saving, and allows less exertation and reduces energy consumption when it is used. Hence this paper highlights human factors and/or ergonomics consideration in the process of design and development of assistive devices synchronising with gerontechnological research and development aiming to emphasise user's requirement.

Cost Savings↗

PubMed2001

Adaptation to night shifts and synchronisation processes of night workers.

Human beings are accustomed to being active and awake during the day, and asleep and rest at night. Since we live in a society which is organised predominantly along daytime activity, therefore working in the night shift may deeply disrupt our social and family life. It is also a well-known fact that night shift causes fatigue and circadian disruption. The basic manifestation of fatigue and circadian rhythm has been linked to health and safety problems, involving decrements in psychophysical and physiological functions, plus subjective complaints. In this context quantitative relationships between shift work and circadian rhythm need to be assessed to explore suitable time schedule, and to minimise sleep depth and fatigue. There is also a great need to discuss circadian disruption, sleepiness and the increasing cost of work related illness among night workers. In this regard, some aspects of fatigue and circadian disruption caused from night shift work are revealed in this paper aiming to increase workers' health, safety and well being as well as productivity. Light/dark cycle and social stimuli issues acting on the circadian timing systems are also explored to solicit opinions and discussion on the controversy of night work. Suggestions are therefore likewise given to enhance workers' adaptation to night shift and synchronization process.

Adaptation, Physiological↗

PubMed2001

MIB-I as a proliferative activity marker of the multiform glioblastomas.

MIB-I is a proliferative activity marker of multiform glioblastomas which are the most frequent tumors of the central nervous system. They are characterizad by differential rate and prognosis. The aim of the study was to determine the proliferative activity of multiform glioblastomas and estimation of the correlation between tumors' proliferative activity and tumors' localization, size, patients' age and sex. 24 patients (18 females and 6 males) with multiform glioblastomas were analyzed. The mean patients' age was 52.1. The proliferative activity was calculated as a proliferation index: IP for MIB-I. Cells with positive reaction were determined by MIB-I which was compared to all neoplastic cells. The most frequent localization of the tumors were frontal and temporal lobes of the brain. The size of the tumors ranged from 2.5 to 5.3 cm (mean 3.9). Mean IP was 43.2 (SD+/-17.4). We found no correlation between IP MIB-I and localization of the tumor, patients' age and sex. There was a marginal statistically significant correlation between IP MIB-I and size of the tumor (p=0.005).

Antigens, Nuclear↗

PubMed2001

[Magnetic resonance proton spectroscopy in neurooncology--preliminary report].

UNLABELLED: MR proton spectroscopy (1H MRS) has been widely applied in characterisation and differentiation of brain tumors, staging, recurrence of pathologic process, post radiotherapy changes and other lesions mimicking neoplasm like abscesses. Despite of many studies performed over last 3 years in many countries spectroscopic pattern (phenotype) of brain tumors is still not well estimated and the role of each metabolite as an indicator of histopathologic grade and type of the tumor is still unknown. MATERIALS AND METHODS: In vivo 1H MR spectroscopy was prospectively performed in 36 patients with intracranial tumors (low grade gliomas, high grade gliomas, meningiomas and abscesses). Examinations was performed with 1.5 T system, using voxels of 8 cc. RESULTS: In high grade gliomas level of NAA was decreased, and consequently low ratios of NAA to other metabolites were obtained; lactate and choline peaks were markedly increased. In patients with meningiomas signal of NAA was reduced, while in abscesses group peaks of acetate and succinate were observed. Authors analysed ratios of metabolites in above-mentioned tumors. The method is especially useful in differential diagnosis in neoplastic and nonneoplastic cases. CONCLUSIONS: Our study confirms diagnostic value of 1H MRS in doubtful cases of intracranial tumors.

Brain Abscess↗

PubMed2000

Intracranial pressure processing with artificial neural networks: prediction of ICP trends.

It is well known that intracranial pressure (ICP) is influenced by an array of predictable and unpredictable factors, which gives rise to a signal heavily loaded with stochastic, i.e. random components. Hence, statistical modelling of this signal has proved to be of limited utility, in spite of the very sophisticated mathematical methods applied. In recent years, neural network algorithms (ANN), which are an alternative to statistical methods, have proved their effectiveness in the prediction of trends, as applied in a variety of medical and non-medical tasks. We therefore attempted to test the efficiency of neural models in the on-line prediction of ICP values, compare their effectiveness to statistically oriented algorithms and combine ANN methods with some newer signal processing algorithms, like wavelet decomposition. Prediction horizons of up to 5 minutes have been tested with various architectures of the neural predictor. For a 3 minute prediction horizon, a satisfactory accuracy of forecasting has been achieved with "plain" ANN, as expressed by the "average relative variance coefficient". This was measured by the ratio of the prediction error obtained, in relation to the error which would occur if a current value were taken as the forecasted one. The prediction quality with statistical autoregressive models has proved unsatisfactory, whilst the result obtained using the ANN model with the wavelet transform incorporated, performed significantly better than the ANN models alone. The prediction quality obtained with the ANN methodology seems to be satisfactory over a short time horizon, though no conclusion can be derived at this stage of the study, as to the clinical utility of this method. In particular, even with this methodology, it is not possible to forecast any sudden dehiscencies of the ICP signal with any practical reliability. From the point of view of modelling theory, such sharp deviations of the signal may be regarded as a "catastrophe". This implies the necessity for a different approach to the ICP signal analysis with the artificial intelligence methodology; one, that is more oriented towards the global properties of the signal.

Cerebral Hemorrhage↗

PubMed2000

Intracranial pressure processing with artificial neural networks: classification of signal properties.

Intracranial pressure (ICP) is commonly used by neurosurgeons as a source of valuable information about the current condition of the neurosurgical patient. Nevertheless, despite years of effort, extracting clinically valuable information from the ICP signal is still problematical. Approaches, using current values of ICP, may fail to disclose imminent risk, because unpredictable factors can rapidly change the properties of the signal. An alternative approach is to determine some global characteristics of the signal within a longer time interval and such statistical analyses have been proposed by several authors. A further, rarely considered, problem is assessment of the results obtained from the point of view of their practical utility and/or such classification of the obtained properties of the signal that they correspond to certain clinical states of the patient. While this might be a typical task for discriminant analysis, we approached the analysis using an alternative methodology, that of computational intelligence, implemented in artificial neural networks (ANN). We tested two variants of the ANN algorithms for classification and discrimination of global properties of the ICP signal. In a "dynamic pattern classification" the network was presented with several sections of ICP records together with information from the expert-neurosurgeon, classifying 4 risk groups. In this mode no data pre-processing was carried out, in contrast to our second approach, in which the signal had been pre-processed using published statistical analyses and only these intermediate coefficients were fed into the ANN classifier. The results obtained with both classification methods at their current stage of training were similar and approximated to a 70% rate of judgements consistent with the expert scoring. Nevertheless, the method based on the assessment of global parameters from the ICP record looks more promising, because it leaves the possibility for modification of the set of parameters analysed. The new parameters may include information extracted not only from the ICP signal, but also from other diagnostic modalities, like colour coded Doppler ultrasonography. The ultimate goal of this work is to build up a pseudo-intelligent computer expert system, which would be able to reason from a reduced set of input information, available from a standard monitoring modality, because it had been taught salient links between these data and higher-order data, upon which expert scoring was based.

Cerebral Hemorrhage↗

PubMed1999

Direct cooling of the human brain by heat loss from the upper respiratory tract.

This study is the first report on human intracranial temperature in conscious patients during and after an upper respiratory bypass. Temperatures were measured in four subjects subdurally between the frontal lobes and cribriform plate (T(cr)) and on the vault of the skull (T(sd)). Further measurements were taken in the esophagus (T(es)) and on the tympanic membrane. Reinstitution of airflow in the upper respiratory tract under conditions of mild hyperthermia gave a rapid drop in T(cr) of 0.4-0.8 degrees C. In three patients the intracranial temperature at the basal aspect of the frontal lobes fell below T(es). Thus local selective cooling of the brain surface below that of the trunk temperature was shown to occur. Intensive breathing by the patients after extubation for a 3-min period produced a cooling at the site of T(cr) measurement at a rate of up to 0.1 degrees C/min, and this response could be evoked on demand. The results support the view that cooling of the upper airway can directly influence human brain temperature.

Adult↗

PubMed1999

Transcranial color Doppler sonography of basal cerebral arteries in 182 healthy subjects: age and sex variability and normal reference values for blood flow parameters.

OBJECTIVE: Only a limited number of transcranial color-coded Doppler studies have provided ranges for the normal reference values of cerebral hemodynamic parameters. These reports are not fully convergent in relation to the range of values or to the age and sex dependence of blood flow parameters. The aim of the present study was to provide data regarding normal reference ranges. SUBJECTS AND METHODS: We examined 182 healthy volunteers (79 men and 103 women; age range, 20-86 years old) with color-coded Doppler sonography via a temporal acoustic window with a 2.5-MHz transcranial probe. The subjects were divided into three age groups: 20-40 years old (group 1), 41-60 years old (group 2), and more than 60 years old (group 3). Angle-corrected peak systolic, end-diastolic, and mean velocities as well as impedance indexes were determined in anterior, middle, and posterior cerebral arteries. RESULTS: Mean velocity values for middle, anterior, and posterior cerebral arteries in age group 1 were 81+/-20, 56+/-14, and 52+/-12 cm/sec (mean +/- SD), respectively. In group 2, the values were 73+/-19, 53+/-16, and 51+/-12 cm/sec (mean +/- SD), and in group 3, the values were 59+/-11, 44+/-11, and 40+/-9 cm/sec (mean +/- SD). Decrease in blood flow velocities and a concomitant increase in impedance indexes were found in all vessels with advancing age-findings that were most pronounced in subjects who were more than 40 years old. In the 20- to 40-year-old group, mean velocities for all vessels were higher in women than in men, whereas impedance indexes were not significantly different. CONCLUSION: Flow velocities in basal cerebral arteries range widely and are significantly age dependent. Age and sex matching of Doppler sonographic data is a prerequisite for clinically valuable conclusions.

Adult↗

PubMed1999

The influence of post-traumatic syndrome in determining capacity to return to work after closed head injury.

Neuropsychological deficits following closed head injury are responsible for a significant part of the post-traumatic syndrome. Nonetheless such deficits frequently elude standard neurological examination and head injured subjects are not recognised as suffering from any impairments, despite these having a significant effect on their ability to return to work. As a result, subjects are refused disability status, resulting in a large number of litigation appeals. The criteria for determining disability status after head injury are often inadequate, as they do not take into account the post-traumatic syndrome, and medical experts, if they are sensitive to these issues are left in a quandary as to how to justify their decisions before the courts. Equally, psychological assessment, where it is included, is frequently limited to the examination of intellectual functions and memory, which are not always grossly disturbed in these cases. It is recommended that neuropsychological assessments should form part of routine practice in the evaluation of outcome in closed head injury and the test instruments be of adequate sensitivity to measure the deficits occurring after head injury. However, it is necessary to bear in mind that these subjective symptoms, which in reality hamper subjects' ability to return to work, may be the result of disruption of fine cognitive functions, which are inaccessible to currently available test methods.

Adult↗