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Biomedical subjects

M Lewandowski

Publications and source records attributed to M Lewandowski.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiology of ARDS.

For decades the incidence of the acute respiratory distress syndrome (ARDS) has been unclear. A first effort to tackle the problem was undertaken by the National Heart and Lung Task Force who, in 1972, provided the scientific community with an arguable estimate of 75 cases per 100,000 inhabitants/year for the USA. Nearly 20 years later, the first population based studies yielded figures of 1.5-4.5 cases per 100 000 inhabitants/year in Europe. Epidemiologic research became much more focused when in 1992 the new ARDS and acute lung injury (ALI) definitions of the American-European Consensus Conference became available. In subsequent studies in which these refined definitions were used, incidence figures ranging from 13-23 cases per 100,000 inhabitants/year for ARDS and 18 cases per 100,000 inhabitants/year for ALI were reported. Latest results from a high-class epidemiological study conducted in Seattle, suggested ARDS/ALI incidence figures of 59 and 79 cases per 100,000 inhabitants/year, respectively. These new figures, similar to the one proposed in 1972, led to a paradigm shift: ARDS and ALI are no longer viewed as rare syndromes but as widespread diseases with a massive socio-economic impact that is comparable with the burden from breast cancer, AIDS, asthma or myocardial infarction.

Humans↗
PubMed2005

Comparison of sound fields generated by different coded excitations--experimental results.

This work reports the results of measurements of spatial distributions of ultrasound fields obtained from five energizing schemes. Three different codes, namely, chirp signal and two sinusoidal sequences were investigated. The sequences were phase modulated with 13 bits Barker code and 16 bits Golay complementary codes. Moreover, two reference signals generated as two and sixteen cycle sine tone bursts were examined. Planar, 50% (fractional) bandwidth, 15 mm diameter source transducer operating at 2 MHz center frequency was used in all measurements. The experimental data were collected using computerized scanning system and recorded using wideband, PVDF membrane hydrophone (Sonora 804). The measured echoes were compressed, so the complete pressure field in the investigated location before and after compression could be compared. In addition to a priori anticipated increase in the signal to noise ratio (SNR) for the decoded pressure fields, the results indicated differences in the pressure amplitude levels, directivity patterns, and the axial distance at which the maximum pressure amplitude was recorded. It was found that the directivity patterns of non-compressed fields exhibited shapes similar to the patterns characteristic for sinusoidal excitation having relatively long time duration. In contrast, the patterns corresponding to compressed fields resembled those produced by brief, wideband pulses. This was particularly visible in the case of binary sequences. The location of the maximum pressure amplitude measured in the 2 MHz field shifted towards the source by 15 mm and 25 mm for Barker code and Golay code, respectively. The results of this work may be applicable in the development of new coded excitation schemes. They could also be helpful in optimizing the design of imaging transducers employed in ultrasound systems designed for coded excitation. Finally, they could shed additional light on the relationship between the spatial field distribution and achievable image quality and in this way facilitate optimization of the images obtained using coded systems.

Journal Article↗
PubMed2005

Identification and quantification of aerosol polar oxygenated compounds bearing carboxylic or hydroxyl groups. 2. Organic tracer compounds from monoterpenes.

In this study, a comparison is made of polar organic compounds found in the field with those produced in secondary organic aerosol from laboratory irradiations of natural hydrocarbons and oxides of nitrogen (NOx). The field samples comprised atmospheric particulate matter (PM2.5) collected at Research Triangle Park (RTP), NC, during the summer of 2003, and the laboratory samples originated from the photooxidation of the following monoterpenes: alpha-pinene, beta-pinene, and d-limonene. To determine the structural characteristics of the polar compounds, the filter samples were solvent extracted and derivatized using a technique based on single and multistep derivatizations. The resulting compound derivatives were analyzed by GC-MS in the methane-Cl and El modes. In addition to previously reported biogenic oxidation products (pinic acid, pinonic acid, norpinic acid, nopinone, and pinonaldehyde), seven multifunctional organic compounds were found in both field and laboratory samples. These compounds, which are proposed as possible atmospheric tracers for secondary organic aerosol from monoterpenes, were consistent with the following identifications: 3-isopropyl pentanedioic acid; 3-acetyl pentanedioic acid; 3-carboxy heptanedioic acid; 3-acetyl hexanedioic acid; 2-isopropyl-1,2-dihydroxybutanol; 4-isopropyl-2,4-dihydroxyhexanol; and 3-(2-hydroxy-ethyl)-2,2-dimethyl-cyclobutane carboxylic acid. Initial attempts have been made to quantify the concentrations of these tracer compounds on the basis of surrogate compound calibrations. The occurrence of these compounds in both laboratory and field measurements suggests that secondary organic aerosol originating from biogenic hydrocarbons are contributing to the regional aerosol burden in the southeastern United States. Several of these compounds also appear to contribute to the global aerosol burden in that they have also been identified in Europe and Brazil.

Aerosols↗
PubMed2004

Identification and quantification of aerosol polar oxygenated compounds bearing carboxylic or hydroxyl groups. 1. Method development.

In this study, a new analytical technique was developed for the identification and quantification of multifunctional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) of the multifunctional compound using an alcohol (e.g., methanol, 1-butanol) in the presence of a relatively strong Lewis acid (BF3) as a catalyst. This esterification reaction quickly and quantitatively converts carboxylic acids to their ester forms. The second step is based on silylation of the ester compounds using bis(trimethylsilyl) trifluoroacetamide (BSTFA) as the derivatizing agent. For compounds bearing ketone groups in addition to carboxylic and hydroxyl groups, a third step was used based on PFBHA derivatization of the carbonyls. Different parameters including temperature, reaction time, and effect due to artifacts were optimized. A GC/MS in EI and in methane-CI mode was used for the analysis of these compounds. The new approach was tested on a number of multifunctional compounds. The interpretation of their EI (70 eV) and CI mass spectra shows that critical information is gained leading to unambiguous identification of unknown compounds. For example, when derivatized only with BF(3)-methanol, their mass spectra comprise primary ions at m/z M.+ + 1, M.+ + 29, and M.+ - 31 for compounds bearing only carboxylic groups and M.+ + 1, M.+ + 29, M.+ - 31, and M+. - 17 for those bearing hydroxyl and carboxylic groups. However, when a second derivatization (BSTFA) was used, compounds bearing hydroxyl and carboxylic groups simultaneously show, in addition to the ions observed before, ions at m/z M.+ + 73, M.+ - 15, M.+ - 59, M.+ - 75, M.+ - 89, and 73. To the best of our knowledge, this technique describes systematically for the first time a method for identifying multifunctional oxygenated compounds containing simultaneously one or more hydroxyl and carboxylic acid groups.

Aerosols↗
PubMed2003

[Scoring systems in the intensive care unit].

Scoring systems represent classification systems or point systems which have been designed for making quantitative statements regarding the severity of a disease, its prognosis, and its course. Furthermore, scores may serve the purposes of assessing therapies, of quality control and of quality assurance, and of an economic evaluation of intensive care. Like all measuring methods, scores are susceptible to failures and systematic mistakes. The clinical user should be well aware of these limitations. Generally, one would recommend only using scores which have been rigorously tested for their reliability, validity, and practicability. These include, but are not limited to, the updated versions of the APACHE, the SAPS, and the MPM. Although great strides have been made concerning development, verification, and clinical applicability, scores still exhibit a level of uncertainty which precludes their use in individual patients. Frequently, it may be of benefit to combine the more general scores with one or several organ dysfunction scores to determine the extent of functional impairment of specific organs. If, however, well-trained medical personnel apply tried and tested scoring systems, intensive care units will definitely gain a lot from it.

APACHE↗
PubMed2001

[Is application of electrocardiographic exercise test always usefull in the diagnosis of coronary artery disease? Advantages and limitations of this method].

UNLABELLED: To determine the diagnostic value of the electrocardiographic exercise testing (EET) in 551 patients with chest pain regarded as definite or probable stable angina pectoris (CAD), results of performed EET were compared with coronary angiography. All patients underwent exercise testing according to the Bruce protocol. The criterion for a positive exercise ST-segment response was > or = 1 mm of horizontal or down sloping depression 80 msec after J-point. The indications for cardiac catheterization in each patient were determined at the discretion of the attending physician. Clinically important coronary artery disease was defined as > 50 per cent narrowing of the diameter of at least one major vessel or > or = 50 per cent of the left main coronary artery. RESULTS: The sensitivity and specificity of EET for detection of CAD were for the entire group, in women and men respectively: 93%, 91%, 94% and 21%, 16%, 27%. CONCLUSION: 1. Indications for EET should be based on prior probability of coronary artery disease. 2. Application of higher than conventional ST depression criteria (> or = 2 mm) lowers sensitivity but increases specificity of EET. 3. Variables determining false positive results are as follows: age, sex (female), low probability of CAD, ST-segment depression in leads: II, III, aVF and mitral valve prolapse. 4. Variables determining false negative results are as follows: high probability of CAD, sex (male) and one vessel disease.

Adult↗
PubMed2001

[Taking history in diagnosing coronary artery disease in the 21st century--wasting time or a valuable diagnostic tool?].

UNLABELLED: The relation of chest pain characteristics and other features of the history of disease to coronary angiograms was assessed in 551 patients with chest pain regarded as definite or probable stable angina pectoris. A standardised questionnaire was used to record demographic details and chest pain characteristics of interviewed patients. The differentiation between typical, atypical or nonanginal pain was based on classification proposed by Diamond. The indications for catheterization in each patient were determined at the discretion of the attending physician. All patients underwent diagnostic coronary angiography (clinically important coronary artery disease was defined as > 50 per cent narrowing of the diameter of at least one major vessel or > or = 50 per cent of the left main coronary artery). CONCLUSION: Chest pain characteristics remains an effective tool for estimating probability of coronary artery disease.

Adult↗
PubMed2000

Thermally excited multiplet states in macerals separated from bituminous coal

Electron paramagnetic resonance searches of thermally excited multiplet states in macerals, exinite, vitrinite, and inertinite of Polish medium-rank coal (85.6 wt% C), were performed. Numerical analysis of lineshape indicates a multicomponent structure of the EPR spectra of macerals heated at 300 degrees and 650 degrees C. EPR spectra of exinite and vitrinite are a superposition of broad Gauss, broad Lorentz (Lorentz 1), and narrow Lorentz (Lorentz 3) lines. Two narrow Lorentz (Lorentz 2 and Lorentz 3) lines were observed in the resonance absorption curves of inertinite. The influence of the measuring temperature (100-300 K) on the EPR lines of the macerals was also studied. The experimentally obtained temperature dependence of the EPR line intensities were fitted by the theoretical functions characteristic for paramagnetic centers with ground doublet state (S = 12) and paramagnetic centers with thermally excited triplet (S = 1) and quadruplet (S = 32) states. Thermally excited multiplet states were found in exinite and vitrinite. Both paramagnetic centers with doublet ground state (S = 12) and paramagnetic centers with thermally excited states, probably quadruplet states (S = 32), exist in the group of paramagnetic centers of exinite and vitrinite with the broad Lorentz 1 lines. Intensities (I) of the broad Gauss and the narrow Lorentz 3 lines of exinite and vitrinite changes with temperature according to the Curie law (I = C/T). The existence of thermally excited multiplet states was not stated for inertinite. The two groups of paramagnetic centers of inertinite with Lorentz 2 and Lorentz 3 lines obey the Curie law. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Skin imaging with high frequency ultrasound - preliminary results.

This study presents the detailed construction and the principle of performance of high frequency (HF) ultrasound scanner for skin examination. The aim of this study was to show a difference between diseased and healthy skin and to evaluate the usefulness of the scanner in monitoring of therapeutic efficacy of morphea and lichen sclerosus et atrophicus (LSA). We examined 48 patients aged between 15 and 64 years; 25 patients with plaque-type morphea, nine patients with linear morphea and 14 patients with LSA. In the course of 18 months all patients were examined before, during and after treatment. In 29 patients ultrasonographic evidence of regression (decreasing of the skin thickness) was observed, in eight patients ultrasound examination showed progression and in 12 patients no difference in the ultrasound scan before and after treatment could be shown. Our study shows that HF ultrasound scanner is suitable to differentiate between the healthy and diseased skin in morphea and LSA as well as to evaluate the treatment efficacy of these diseases.

Adolescent↗
PubMed2000

Hydatidiform mole in 59-years-old woman: a case report.

We describe a clinical data and histopathological findings in hydatidiform mole found in 59-years-old woman. The patient was admitted to Hospital with vaginal bleeding. Diagnostic curettage revealed hydatidiform mole VI group according to Hertig-Sheldon classification. The patient underwent transabdominal hysterectomy and bilateral oophorosalpingectomy. The serum level of beta-HCG has decreased from initially observed 128.6 U/l to less than 3 U/l after 3 courses of MTX therapy. Patient is under every-six-month observation. No further treatment is planned.

Female↗
PubMed1999

Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients: preliminary findings.

OBJECTIVE: The authors investigated the links between depression, cardiac disease, and microcirculatory cerebral blood flow (CBF). METHOD: A magnetic resonance imaging technique based on arterial spin tagging was used to estimate microcirculatory CBF in depressed (N = 5) and comparison (N = 14) elderly subjects with coronary artery disease. Signal intensity ratios corresponding to relative microcirculatory CBF were calculated for four regions on two axial images through the upper and lower halves of the lateral ventricles. RESULTS: On the superior image, estimates of microcirculatory CBF were statistically significantly lower on the left side in the depressed subjects than in the nondepressed group. When the ratios in the superior and inferior images were averaged, the depressed subjects had lower values for both left periventricular regions of interest and the parietal region. CONCLUSIONS: Despite the small study group and indirect estimates of blood flow, these preliminary findings suggest that a relative cerebral hypoperfusion may underlie depression in elderly cardiac patients.

Age Factors↗
PubMed1999

Strumal carcinoid of ovary. A case report with immunohistochemical investigations.

Clinical, histological and immunohistochemical findings in a rare ovarian tumor--strumal carcinoid--are presented. Neuropeptides detected by immunoreactions revealed the origin of tumor cells from the midgut. Immunohistochemical reaction revealed parathyroid hormone-related protein (PTHrp) in the carcinoid cells. After surgical resection of the tumor a decrease in serum calcium level was observed.

Carcinoid Tumor↗
PubMed1999

[The diagnostic value of resting electrocardiography in stable coronary artery disease].

The relation of resting electrocardiographic (ECG) patterns to angiographic features was assessed in 566 patients with chest pain regarded as definite or probable stable angina pectoris. The indications for catheterization in each patient were determined at the discretion of the attending physician. All patients underwent diagnostic coronary angiography (clinically important coronary artery disease was defined as > or = 70 per cent narrowing of the diameter of at least one major vessel or > or = 50 per cent of the left main coronary artery) and standard 12 lead electrocardiography which was interpreted by 2 cardiologists independently in coordinating centre. The signs of impaired coronary blood flow were assessed by abnormalities of repolarization (among others S-T segment, the T wave), depolarization and presence of disturbances of cardiac rythm. The resting routine electrocardiogram was assigned to one of three categories: normal, nonspecific abnormalities or typical for coronary insufficiency. The typical pattern for ischemia was present in 104 patients (18%), nonspecific abnormalities were present in 185 patients (33%) and electrocardiogram was normal in 277 patients (49%). Sensitivity and specificity of the typical for coronary insufficiency resting ECG was calculated: 23% and 87% respectively for the entire group, 33% and 81% in women, 20% and 93% in men. In the group with normal resting electrocardiographic pattern 55% of patients have significant stenosis in at least one major coronary artery.

Cardiac Catheterization↗
PubMed1996

Evidence of nitric oxide in the exhaled gas of Asian elephants (Elephas maximus).

Nitric oxide (NO) produced in the respiratory tract is released into the respiratory gases of humans, rabbits, guinea-pigs, and rats. We analysed the NO concentrations in the exhaled gas of four awake Asian elephants. Two methods were employed: (1) exhaled gas was sampled from the elephants' trunks with a 1 L syringe and analysed for NO concentrations by chemiluminescence; (2) respiratory gas was continuously aspirated via a thin plastic tube positioned within the trunk and on-line analysed for NO concentrations by chemiluminescence. Syringe sampling (n = 4), when corrected for dilution by ambient air using linear regression analysis, revealed a mean NO concentration of 31 parts per billion (ppb); highest exhalatory concentrations measured during continuous suctioning were 27 and 28 ppb (n = 2). The exhaled NO concentrations in elephants are similar to those found in humans measured with a comparable technique. This supports the hypothesis that a size-independent 'normal value' of endogenous NO is provided in the airways which may contribute to regulation of pulmonary ventilation and perfusion by autoinhalation in some mammals.

Animals↗
PubMed1991

Echographic diagnosis of anterior hyaloidal fibrovascular proliferation.

High-resolution contact B-scan echographic imaging of the ciliary body and peripheral retina was performed on five eyes with anterior hyaloidal fibrovascular proliferation and media opacity by means of a wide (58 degrees) scanning arc. This technique determined the circumferential and anteroposterior extent of peripheral traction retinal detachment associated with anterior hyaloidal fibrovascular proliferation, which correlated highly with findings at subsequent vitrectomy. Final visual acuity of 20/400 or better was achieved in the two eyes (50%) with more limited peripheral traction detachment. In the presence of media opacity, anterior echographic imaging may allow early detection of traction retinal detachment associated with anterior hyaloidal fibrovascular proliferation and may be useful in characterizing the severity of this condition.

Adult↗
PubMed1991

Acetanilide 4-hydroxylase and acetanilide 2-hydroxylase activity in hepatic microsomes from induced mice.

A simple and sensitive method for the separation of 14C-labelled acetanilide, 4-hydroxyacetanilide, 3-hydroxyacetanilide and 2-hydroxyacetanilide was developed using thin-layer chromatography. This separation is the basis for the assay of acetanilide 4-hydroxylase and acetanilide 2-hydroxylase activity in liver microsomes from DBA2/N male mice that had been treated with phenobarbital, 3-methylcholanthrene, isosafrole or n-butylbenzodioxole. Microsomes were incubated with [14C]acetanilide and extracted with benzene and ethyl acetate. The extract was applied to silica gel plates and developed with a hexane/isopropanol/ammonium hydroxide/water solvent system. The radiolabelled phenolic metabolites and the parent compound were detected using a Berthold Automatic TLC Linear Analyzer. Although the 4-hydroxylated metabolite was the primary product detected, this method can be used to detect other phenolic metabolites.

Acetanilides↗