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R Olszewski

Publications and source records attributed to R Olszewski.

At least 19 recordsLinked to original sources
PubMed2006

3D CT-based cephalometric analysis: 3D cephalometric theoretical concept and software.

INTRODUCTION: We present an original three-dimensional cephalometric analysis based on a transformation of a classical two dimensional topological cephalometry. METHODS: To validate the three-dimensional cephalometric CT based concept we systematically compared the alignments of anatomic structures. We used digital lateral radiography to perform the classical two-dimensional cephalometry, and a three-dimensional CT surface model for the three-dimensional cephalometry. RESULTS: Diagnoses based on both two-dimensional and three-dimensional analyses were adequate, but the three-dimensional analysis gave more information such as the possibility of comparing the right and left side of the skull. Also the anatomic structures were not superimposed which improved the visibility of the reference landmarks. CONCLUSION: We demonstrated that three-dimensional analysis gives the same results as two-dimensional analysis using the same skull. We also present possible applications of the method.

Cephalometry↗
PubMed2005

[Evaluation of some selected structural and functional parameters of red blood cells as oxidative stress markers in elderly people].

UNLABELLED: The ageing process induces age-related involutionary changes and leads to increased occurrence of many diseases. One of the most important theories of ageing and development of many pathologies is the free radical theory, which assumes that ageing process leads to lost of oxidative balance. THE AIM: of the research was to evaluate the degree of membrane lipid peroxidation, internal microviscosity, activity of membrane ATPase, both total and Na(+)K(+)-dependent, and markers of oxidative damage in erythrocyte membrane protein in elderly people. MATERIAL: The examination was performed on 35 people. The examined group (15 persons, mean age 71,3) consisted of healthy elderly people. The reference group was formed with younger healthy people (20 persons, mean age 55). RESULTS: Erythrocyte membrane lipid peroxidation was found stronger in the group of elderly people. Erythrocyte internal microviscosity was significantly higher in the elderly. The activity of ATPase, both total and Na(+)K(+)-dependent, appeared remarkably greater in the group of younger people. Stronger membrane lipid damage was observed in older age group, which may be implied by lower--SH group concentration, and higher W/S parameter value. CONCLUSION: The obtained results reveal that in elderly people the intensification of oxidative stress in the entire body occurs, which may be confirmed by structural and functional oxidative erythrocyte damage. This conclusion may be significant for pathogenesis of many diseases in this period of life.

Adenosine Triphosphatases↗
PubMed2004

Removing a barrier to computer-based outbreak and disease surveillance--the RODS Open Source Project.

INTRODUCTION: Computer-based outbreak and disease surveillance requires high-quality software that is well-supported and affordable. Developing software in an open-source framework, which entails free distribution and use of software and continuous, community-based software development, can produce software with such characteristics, and can do so rapidly. OBJECTIVES: The objective of the Real-Time Outbreak and Disease Surveillance (RODS) Open Source Project is to accelerate the deployment of computer-based outbreak and disease surveillance systems by writing software and catalyzing the formation of a community of users, developers, consultants, and scientists who support its use. METHODS: The University of Pittsburgh seeded the Open Source Project by releasing the RODS software under the GNU General Public License. An infrastructure was created, consisting of a website, mailing lists for developers and users, designated software developers, and shared code-development tools. These resources are intended to encourage growth of the Open Source Project community. Progress is measured by assessing website usage, number of software downloads, number of inquiries, number of system deployments, and number of new features or modules added to the code base. RESULTS: During September--November 2003, users generated 5,370 page views of the project website, 59 software downloads, 20 inquiries, one new deployment, and addition of four features. CONCLUSIONS: Thus far, health departments and companies have been more interested in using the software as is than in customizing or developing new features. The RODS laboratory anticipates that after initial installation has been completed, health departments and companies will begin to customize the software and contribute their enhancements to the public code base.

Disease Outbreaks↗
PubMed2004

[Limitations of orthognathic model surgery: theoretical and practical implications].

Orthognathic model surgery is a classical technique used to simulate orthognathic surgical cases. However, a detailed analysis of this technique demonstrates that theoretical errors and inaccuracies can occur in routine practice. 2D and 3D cephalometric analysis is the first source of inaccuracies. Then, during the occlusal plane transfer from the patient to the semi-adjustable dental articulator, errors can occur by inaccurate manipulation of the facial bow. Simulating the operation on the plaster cast is difficult due to the lack of a real link between the cephalometric analysis and the model surgery. Rotation and translation movements of the plaster casts are insufficiently controlled during the model surgery stage. Finally, the splint, which transfers the final relative position of maxilla to the mandible, summates all of the errors of the previous stages.

Cephalometry↗
PubMed2004

[Maxillo-facial surgery in the future, interdisciplinary innovation for medicine].

The computer assisted craniomaxillofacial surgery (CAS-CMFS) is an emergent scientific domain in interaction between maxillofacial surgery, three dimensional CT imaging and remote signal engineering. The different stages to develop a synergy between these scientific areas are presented on example of the HEROL project (2002-2006, Region Wallonne grant). The 3D cephalometric analysis is made first with an original ACRO 3D software. Then, the craniomaxillofacial surgery preoperative planning, using 3D informations from ACRO 3D, is performed with ACROSIM 3D software. The major information concerning craniomaxillofacial surgery (incisions, nerve visualization, osteotomy lines visualization, ostheosynthesis position visualization) are transmitted from the virtual word (ACRO 3D & ACROSIM 3D), through the augmented reality (AR) head-mounted display, to the operating theatre. This study describes the HEROL project real advancement and future potential applications of AR in surgery.

Facial Bones↗
PubMed2001

Stimulation of neutrophil activation during coronary artery bypass grafting: comparison of crystalloid and blood cardioplegia.

BACKGROUND: During myocardial ischemia, activation of polymorphonuclear neutrophils (PMNs) results in the production of free oxygen radicals, which increase myocardial injury. It has been shown that PMNs also produce nitric oxide. It is not clear whether PMNs become activated as a result of their direct contact with ischemic/reperfused myocardium or if PMN activation and free oxygen radical production are effects of specific stimuli released during coronary artery bypass grafting (CABG). The aim of the current study was to evaluate plasma-mediated neutrophil stimulation and production of superoxide anion (O2) and nitric oxide in patients undergoing CABG, and to verify whether crystalloid and blood cardioplegia can modify such stimulation. METHODS: Coronary sinus, peripheral arterial, and venous plasma samples were collected from 50 patients who underwent CABG and were divided into 2 equal groups which received either crystalloid or blood cardioplegia: directly before myocardial ischemia and aortic cross-clamping; at the beginning of reperfusion after aortic clamp release; and 30 minutes after reperfusion. O2 and nitric oxide production by PMN was evaluated by standard methods. RESULTS: There was a significant (p < 0.05) increase in O2 production by PMN incubated with plasma obtained from the coronary sinus immediately after reperfusion in patients receiving crystalloid cardioplegia compared to blood cardioplegia. No difference was observed in plasma stimulation of nitric oxide production by PMN in the 2 groups of patients at different times during the procedure. CONCLUSIONS: Cardioplegia may affect release of neutrophil-oriented stimuli from ischemic myocardium and modify neutrophil activation during coronary artery bypass grafting.

Adult↗
PubMed2000

[Fibrinogen serum levels in patients with stable coronary artery disease and acute coronary syndrome].

Increased plasma fibrinogen level is an important prognostic factor of recurrent unstable angina and myocardial infarction in patients with acute coronary syndrome (ACS). The aim of our study was to assess the plasma fibrinogen level at baseline condition in patients admitted to hospital due to coronary artery disease (CAD). Plasma fibrinogen was measured in 51 consecutive patients presenting with ACS within the last 24 hours and in 50 patients with angiographically proven CAD that was stable for the past 30 days. For statistical analysis Mann-Whitney U test, Student t-test, chi-square test and Pearson correlation was used, p < 0.05 being considered statistically significant. There was significant correlation between fibrinogen level and diagnosis of ACS or CAD (r = 0.29, p = 0.002). In our population plasma fibrinogen levels (g/L +/- SD) were significantly different in patients with ACS when compared to CAD subjects (3.87 +/- 1.2 vs. 3.26 +/- 0.65, p = 0.002). There was difference between ACS and CAD subjects in male:female ratio (40/11 vs. 47/4, p < 0.001) and age (63.4 +/- 10.1 vs. 58.4 +/- 10.0, p = 0.014). Our results confirm the role of fibrinogen in pathogenesis of CAD. In our opinion plasma fibrinogen level may be an important diagnostic tool in assessment of patients with chest pain.

Aged↗
PubMed1999

Endothelin-1 is involved in plasma mediated stimulation of neutrophil adherence during coronary artery bypass grafting.

OBJECTIVE: Myocardial ischaemia followed by reperfusion during coronary artery bypass grafting (CABG) is known to result in the activation of polymorphonuclear neutrophils (PMN). The activation of PMN during ischaemia/reperfusion may be a result of their direct contact with activated endothelial cells and/or an effect of stimuli released from ischaemic myocardium. Increased expression of adhesion molecules on the PMN surface, after activation, leads to coronary capillary plugging with a subsequent decrease in blood flow. The purpose of the study was to evaluate plasma-mediated stimulation of PMN adhesion during CABG and to verify if endothelin-1 (ET-1), known to be a potent stimulus for PMN, is involved in stimulation of neutrophils adhesion mediated by integrins. METHODS: Coronary sinus, peripheral artery and peripheral venous plasma samples were taken from 11 patients undergoing coronary surgery before aortal cross-clamping, at the beginning of reperfusion and 30 min thereafter. PMN isolated from five healthy volunteers were incubated with the plasma (20 samples per patient) in the presence of saline or a specific ET-1 receptor blocker, and PMN adherence to a microtiter plate covered with a monoclonal antibody against CD 18 antigen (beta-subunit of the integrin family of adhesion molecules) was evaluated. RESULTS: We have observed a significant increase in adhesion of PMN incubated in the presence of saline with the plasma taken from coronary sinus at the beginning of reperfusion (7.79+/-1.64% of adhering cells) as compared with plasma obtained before aortal cross-clamping from the same place (6.78+/-1.3%, P = 0.04) and from peripheral artery at the beginning of reperfusion (6.64+/-1.1%, P = 0.04, means +/- SEM). ET-1 receptor blocker, significantly decreased stimulation of PMN adhesion by coronary sinus plasma obtained at the beginning of reperfusion (6.7+/-1.51%, P = 0.02). Plasma levels of ET-1 (ELISA) in the samples taken from coronary sinus at the beginning of reperfusion, were higher than in samples obtained before myocardial ischaemia or 30 min after reperfusion. CONCLUSIONS: We conclude, that soluble stimuli capable of stimulation of PMN adhesion are released following myocardial ischaemia during CABG and ET-1 may be involved in PMN stimulation.

Adult↗
PubMed1999

Plasma-mediated stimulation of neutrophil superoxide anion production during coronary artery bypass grafting: role of endothelin-1.

BACKGROUND: Activation of polymorphonuclear neutrophils (PMN) and subsequent release of free oxygen radicals, including the superoxide anion (O2-) has been shown to result in postischaemic myocardial dysfunction during coronary artery bypass grafting (CABG). Several neutrophil-oriented stimuli are known to be released from myocardium during ischaemia and reperfusion. Release of endothelin-1 has been documented during CABG. The aim of the current study was to evaluate plasma-mediated neutrophil stimulation and to verify whether endothelin-1, known to be a stimulus for PMN, is involved in plasma-mediated stimulation of PMN during coronary artery bypass grafting. METHODS: Plasma samples from peripheral artery, peripheral vein, and coronary sinus were obtained from 21 patients undergoing CABG before aortic clamping (global ischaemia), immediately after beginning reperfusion, and 30 min after reperfusion as well as from healthy controls. Plasma was incubated with PMN isolated from healthy donors preincubated in the presence of saline or specific endothelin-1 receptor antagonist (ET-A). PMN O2- production was measured spectrophotometrically. RESULTS: Plasma samples taken from the coronary sinus at the beginning of reperfusion were capable of higher stimulation of neutrophil superoxide anion production (24.2 +/- 2.0 nmol/5 x 10(6)PMN/30 min) than plasma obtained before reperfusion (15.6 +/- 1.5; p < 0.05) or plasma taken from peripheral artery (17.1 +/- 1.7; p < 0.05). Preincubation of PMN with endothelin-1 receptor antagonist decreased superoxide anion production by cells exposed to plasma taken from coronary sinus at the beginning of reperfusion (17.6 +/- 2.0, p < 0.05). CONCLUSIONS: Transcardiac release of soluble stimuli for PMN occurs as a result of myocardial ischaemia during CABG. Endothelin-1 may be involved in the plasma-mediated stimulation of neutrophil superoxide anion production.

Adult↗
PubMed1999

[Contrast agents in echocardiography].

Contrast echocardiography is new imaging modality dynamically entering to clinical practice. The efficient application of the contrast agents needs some knowledge of microbubbles physics. In this paper the basic principles of echo-contrast effects are presented and ultrasound microbubble fluid dynamics in the ultrasonic pressure field is addressed briefly. The recent developments in harmonic imaging end the transient and non-linear acoustic phenomena allow ultrasound to detect of blood flow in the microcirculation. In the second part of the paper it was demonstrated a potential for myocardial opacification by contrast echocardiography and the more recent application such as myocardial perfusion. The authors also reported intracardiac shunts imaging, enhancing endocardial border definition and bringing out of weak Doppler signals. The review of new contrast agents coming to the clinical practice is presented.

Contrast Media↗
PubMed1998

Three-dimensional echocardiographic evaluation of left ventricular volume: comparison of Doppler myocardial imaging and standard gray-scale imaging with cineventriculography--an in vitro and in vivo study.

BACKGROUND: Standard gray-scale imaging (GSI), three-dimensional (3D) echocardiography has been shown to be superior to two-dimensional echocardiography in measuring left ventricular volume. However, the often relatively poor quality of transthoracic gray-scale data can limit the potential application of this technique. Doppler myocardial imaging (DMI) is a new ultrasound technique that potentially offers higher-quality 3D images with a transthoracic approach than the 3D GSI technique. This study was designed to compare the accuracy of standard GSI and DMI 3D left ventricular volume measurements in vitro and in vivo. METHODS AND RESULTS: In vitro, the minimum and maximum volume of the contracting single-chamber, tissue-mimicking phantom was calculated by using both techniques. In vivo, GSI and DMI 3D left ventricular volume measurements were performed in 16 patients. End-diastolic and end-systolic left ventricular volumes were computed for both techniques and compared with those calculated by cineventriculography. In vitro, both methods tended to underestimate the true phantom volume, but the systematic error was smaller for DMI than for GSI (-1.2% +/- 1.5% vs. -4.3% +/- 3%; p < 0.01) and was more constant in the case of DMI over the range of different sizes of true volume. In vivo, for GSI the end-diastolic volume mean difference was -12.6 ml and the limits of agreement were +/-18 ml, and for DMI the corresponding values were -4.2 and +/- 10.6 ml, respectively. The difference for end-systole was -6.5 +/- 10.6 ml and -1.5 +/- 10 ml for GSI and DMI, respectively. The magnitude of the difference in volume measurement between 3D echocardiography and cineventriculography was significantly smaller when using the Doppler technique. CONCLUSIONS: The results of this in vitro and in vivo study indicate that DMI is superior to GSI as a transthoracic acquisition technique for 3 D volume computation.

Echocardiography, Three-Dimensional↗
PubMed1998

Soluble adhesion molecules in reperfusion during coronary bypass grafting.

OBJECTIVE: Adhesion of activated leukocytes to the endothelial cells as a result of myocardial ischaemia/reperfusion during open chest coronary artery surgery has been shown to be involved in the development of tissue damage. Activated leukocytes adhere to endothelium via adhesion molecules expressed by both cell types, resulting in the impairment of coronary capillary flow. Upon cell activation, adhesion proteins may be released in the soluble form to circulating blood. The purpose of our study was to verify whether myocardial ischaemia/reperfusion occurring during coronary artery bypass grafting results in release of the soluble adhesion molecules VCAM-1, ICAM-1, E-selectin and L-selectin into the circulation. METHODS: Plasma levels of the soluble adhesion molecules were measured in vein, arterial and coronary sinus blood samples taken from 15 patients undergoing coronary artery bypass grafting (CABG). Blood samples for estimations were collected during the procedure: before aorta cross-clamping, at the beginning of reperfusion and 30 min after reperfusion. Soluble adhesion molecules levels were measured by standard ELISA assays. RESULTS: Mean plasma levels of soluble VCAM-1 in arterial samples increased significantly at the beginning of reperfusion and 30 min after reperfusion. In contrast, soluble L-selectin plasma levels in arterial samples remained unchanged. In coronary sinus samples, levels of soluble ICAM-1 significantly increased 30 min after reperfusion. Moreover, in coronary sinus samples collected 30 min after reperfusion, soluble ICAM-1 levels were significantly higher than in arterial samples obtained at the same time. The mean concentration of soluble E-selectin in samples obtained from coronary sinus decreased significantly 30 min after reperfusion. Moreover, plasma levels of soluble E-selectin in coronary sinus samples obtained 30 min after reperfusion were significantly decreased compared with these observed in arterial samples collected at the same time. CONCLUSIONS: The reperfusion of ischaemic myocardium during CABG results in a significant increase in plasma levels of the soluble endothelial adhesion molecules VCAM-1 and ICAM-1 and significant decrease in soluble E-selectin plasma levels. L-selectin plasma levels during CABG procedure remain unchanged. We propose that the increased plasma concentrations of soluble VCAM-1 and ICAM-1 are a result of endothelial cell activation during ischaemia/reperfusion following bypass surgery.

Aged↗
PubMed1998

[The improvement of echocardiographic assessment of the left ventricle by the use of perflenapent and harmonic imaging].

Contrast echocardiography and harmonic imaging (HI) are promising new modalities applied in order to obtain improved visualisation of the left ventricle. Perflenapent (EchoGen, Abbott) is a new generation echocardiographic contrast agent that crosses the pulmonary capillary bed and produces long-term ventricle opacification. Our aim was to assess the left ventricle endocardial visualisation after perflenapent infusion and HI technique. We studied a pilot group of 10 patients (mean age 52.5 +/- 7.6, mean weight 76.9 +/- 10.1 kg, one female) with previously obtained sub-optimal non-contrast echocardiograms. Perflenapent was injected intravenously at dosis 0.05 ml/kg. Echocardiography was performed before perflenapent injection and during the time between injection and LV image disappearance. Images were assessed using four-point scale, 0 standing for the poorest and 3 for excellent visualisation. Perflenapent produced full chamber opacification in all pts. Contrast effect was observed for 550-15824 sec and myocardial enhancement was seen for 176-2116 sec after i.v. administration. After perflenapent administration, endocardial border was significantly better visible than before (1.9 +/- 0.57 vs. 2.9 +/- 0.31, p < 0.001). No hemodynamic effects were noted, as assessed by oxygen saturation, blood pleasure and heart rate. A mild, transient somnolence was seen in one pt. Perflenapent improved left ventricular function diagnostic capabilities, and provided enhanced visualisation of the myocardium.

Adult↗
PubMed1997

Doppler myocardial imaging vs. B-mode grey-scale imaging: a comparative in vitro and in vivo study into their relative efficacy in endocardial boundary detection.

Doppler myocardial imaging (DMI) is a new ultrasound imaging modality in which colour Doppler algorithms are adapted to visualise the myocardium. It allows measurement of regional intramyocardial velocities and quantification of intramural left ventricular function. However promising the technique is, to date the accuracy of endocardial boundary detection by DMI has not been validated. As Doppler velocity estimation is based on measurement of phase shift rather than signal strength, the technique is relatively independent of chest wall attenuation. In the current study, a series of in vitro and in vivo studies was performed to compare standard B-mode grey-scale imaging (GSI) and DMI techniques in endocardial boundary detection. In vitro, the minimum and maximum volumes of a single-chamber tissue-mimicking phantom were calculated using both imaging techniques. In vivo, left ventricular end-diastolic (ED) volume and end-systolic (ES) volume indices were measured from GSI and DMI images in a group of 40 volunteers. All images were obtained in the freeze-frame mode with the Doppler display turned on and off so that simultaneous DMI and GSI information was obtained. In vitro, the limits of agreement between the minimum volume of the phantom and the minimum volume measured by GSI and DMI was 4% and 3%, respectively. For maximum volumes, limits of agreement were 3% for GSI and 2% for DMI. In vivo, the limits of agreement between the two imaging techniques in volume measurements were 6 mL (9%) for ED and 4 mL (11%) for ES. The comparison of the endocardial boundary detection by GSI vs. DMI showed DMI to be significantly superior: ED (72 +/- 16% vs. 85 +/- 8%, respectively; p < 0.05) and ES (71 +/- 13% vs. 88 +/- 7%, respectively; p < 0.05). The results of the study show that: (1) in vitro, based on two-dimensional algorithms, DMI provides as accurate volume measurements as GSI; and (2) in vivo, there is a very good agreement of left ventricular volume measurements between GSI and DMI. However, the endocardial boundary is more reliably displayed and visually easier to detect using DMI than GSI.

Adult↗
PubMed1996

Assessment of wall velocity gradient imaging using a test phantom.

A new phantom has been designed to gain a better understanding of tissue Doppler imaging (TDI). Specifically, the phantom can easily be used to determine myocardial velocity gradients. The phantom mimics the left ventricle and is made of fine-grade sponge material whose ultrasound image closely resembles the gray scale image obtained from heart walls. Theoretical analysis of phantom wall movements offers a plausible explanation for the velocity gradients developing across the heart walls. The results of computer analysis were found to be in very good agreement with TDI M-mode recordings of phantom wall displacement.

Computer Simulation↗