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Biomedical subjects

A Nowicki

Publications and source records attributed to A Nowicki.

At least 37 records · Page 2Linked to original sources
PubMed1997

Subcutaneous self-injection and oral self-administration of metallic mercury--case report.

This paper presents a case of 16-year-old schoolboy who injected subcutaneously about 6 ml of metallic mercury to both forearms and administered orally about 5 ml of it. The patient was admitted to hospital two weeks after this incident without any clinical symptoms. Physical examination and all laboratory tests, including chest x-ray were unremarkable except for granulomata at the injection sites. X-ray examination showed numerous, dispersed globules of mercury in subcutaneous tissue of both forearms and in the digestive tract, mainly in the appendix. Granulomatous tissue with a part of mercury from both forearms as well as appendix were surgically removed. During a six-month period no toxic effects of mercury have been observed, in spite of the fact, that blood mercury level was 132 micrograms/L and urinary mercury level was 500 micrograms/L.

Administration, Oral↗
PubMed1996

Impaired tumor growth in colony-stimulating factor 1 (CSF-1)-deficient, macrophage-deficient op/op mouse: evidence for a role of CSF-1-dependent macrophages in formation of tumor stroma.

Macrophages have been suggested to play a major role in the immune response to cancer. They have also been suggested to stimulate the formation of tumor stroma and to promote tumor vascularization. The availability of the op/op mouse, which has no endogenous colony-stimulating factor 1 (CSF-1) and which possesses a profound macrophage deficiency, provides a new model to verify these notions. Subcutaneous growth of transplantable Lewis lung cancer (LLC) is markedly impaired in the op/op mice compared with normal littermates. Treatment of tumor-bearing op/op mice with human recombinant CSF-1 corrects this impairment. Histological analysis of tumors grown in op/op and normal mice revealed marked differences. Tumors grown in op/op mice display a decreased mitotic index and pronounced necrosis, particularly hemorrhagic. Moreover, particularly in the op/op tumors, peculiar sinusoid-like abortive vessels (not filled with blood) have been observed. These tumors, in contrast to tumors grown in normal mice, are almost deprived of regular arteries and veins. In contrast to tumors grown in normal mice, they exhibit almost no Sirius red-stained collagenous fibers and Gomori silver-stained reticular fibers. Our data suggest that the CSF-1-dependent macrophage subpopulation missing in op/op mice plays a primary role in supporting tumor stroma formation and tumor vascularization in murine LLC tumors.

Animals↗
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↗
PubMed1996

[Neoplasms and congenital abnormalities of extrahepatic bile ducts].

Some problems of association of gallbladder carcinoma and congenital abnormalities of extrahepatic bile ducts are discussed in diagnostic and therapeutic aspects. Presented facts have been not quite clear to explain carcinogenesis of extrahepatic bile ducts.

Bile Duct Neoplasms↗
PubMed1995

Gizzard nematodes of Canada geese wintering in southern Illinois.

Gizzards from 64 hunter-shot Canada geese (Branta canadensis) were collected in southern Illinois (USA) in December 1991 and January 1992 to determine the prevalence and intensity of gizzard nematodes. Three species of gizzard nematodes were recovered: Amidostomum anseris, Amidostomum spatulatum, and Epomidiostomum crami. The prevalence of infection was 98%. Mean intensity was 17.8 nematodes per host and was significantly greater for immature geese (40.3 nematodes/host) than for adult geese (10.9 nematodes/host). The intensity of both A. anseris and E. crami was greater in immature geese, but even the most heavily infected birds did not display serious lesions. Despite a dramatic increase in the population of geese, mean intensity in adult geese was similar to mean intensity reported from earlier studies at the same site. Mean intensity in immature geese in 1991 and 1992 was greater than in earlier studies.

Animals↗
PubMed1994

Comparison of the performance of three maximum Doppler frequency estimators coupled with different spectral estimation methods.

The performance of three spectral techniques (FFT, AR Burg and ARMA) for maximum frequency estimation of the Doppler spectra is described. Different definitions of fmax were used: frequency at which spectral power decreases down to 0.1 of its maximum value, modified threshold crossing method (MTCM) and novel geometrical method. "Goodness" and efficiency of estimators were determined by calculating the bias and the standard deviation of the estimated maximum frequency of the simulated Doppler spectra with known statistics. The power of analysed signals was assumed to have the exponential distribution function. The SNR ratios were changed over the range from 0 to 20 dB. Different spectrum envelopes were generated. A Gaussian envelope approximated narrow band spectral processes (P. W. Doppler) and rectangular spectra were used to simulate a parabolic flow insonified with C. W. Doppler. The simulated signals were generated out of 3072-point records with sampling frequency of 20 kHz. The AR and ARMA models order selections were done independently according to Akaike Information Criterion (AIC) and Singular Value Decomposition (SVD). It was found that the ARMA model, computed according to SVD criterion, had the best overall performance and produced results with the smallest bias and standard deviation. In general AR(SVD) was better than AR(AIC). The geometrical method of fmax estimation was found to be more accurate than other tested methods, especially for narrow band signals.

Doppler Effect↗
PubMed1994

Antigens of adults and third-stage larvae of the meningeal worm, Parelaphostrongylus tenuis (Nematoda, Metastrongyloidea).

We studied the antigens of adults and third-stage larvae of the meningeal worm, Parelaphostrongylus tenuis, in an attempt to identify potential serodiagnostic molecules for this important infection of wild ungulates. Soluble extracts of P. tenuis adult worms and third-stage larvae were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional (2D) electrophoresis and analyzed by immunoblotting using purified rabbit anti-P. tenuis immunoglobulin G (IgG). The IgG antibodies were obtained from animals immunized with P. tenuis adult worm or third-stage larva soluble extract and serum from elk infected with P. tenuis. Out of more than 75 antigens (as shown by 2D electrophoresis and immunoblotting), 7 antigens from adults (four 170-120-kD molecules with isoelectric points between 6.0 and 6.6, two 55-kD molecules with isoelectric points of 5.6 and 5.8, and one 13-kD molecule) and 2 antigens from third-stage larvae (one 25-30-kD molecule with an isoelectric point of 6.3 and one 13-kD molecule) distinguished P. tenuis from two other nematodes, Dictyocaulus viviparus and Trichinella spiralis. Initial results using serum from experimentally infected elk indicate that this serum recognized a similar profile of P. tenuis antigens when compared with the serum from immunized rabbits. This research has set the foundation for the development of a test for P. tenuis infections in wild and recently domesticated elk and and other ungulates.

Animals↗
PubMed1994

Effect of macrophage-modulating agents on in vivo growth of transplantable Lewis lung cancer in mice.

C57Bl/6 mice, bearing transplantable Lewis lung cancer (non-metastatic subline) implanted either subcutaneously or intraperitoneally were treated with macrophage colony stimulating factor (M-CSF, 10(6) units per mouse, per day for 19 days), Escherichia coli lipopolysaccharide or both. Lipopolysaccharide (5 micrograms per mouse) administered daily once a day for up to 30 days impaired both subcutaneous and intraperitoneal tumor growth and prolonged survival of tumor bearing mice. Macrophage colony stimulating factor, administered daily, inhibited only subcutaneous tumor growth, both when administered alone and in combination with with lipopolysaccharide, and had no effect on intraperitoneal tumor. Moreover, it did not prolong survival of tumor bearing mice, when administered alone, and nullified the effects of lipopolysaccharide when administered concomitantly. These data suggest that macrophage colony stimulating factor, at least in this tumor model and in this dose schedule, offers little benefit. In contrast, the present data confirm earlier suggestions on therapeutic usefulness of bacterial lipopolysaccharide in neoplastic disease, which makes this compound an interesting candidate for future clinical trials.

Adjuvants, Immunologic↗
PubMed1991

[False tendons in the left ventricle--an independent arrhythmogenic factor?].

To assess if the presence of false tendons (FT) in the left ventricle can be an independent factor increasing the risk of ventricular arrhythmias in apparently healthy subjects, we examined 38 persons aged 18-60 years in whom during echocardiographic examination we accidently found FT in the left ventricle. No other echocardiographic disorders were present. Physical examination, ECG and stress ECG showed no symptoms of heart disease. The only ischaemic heart disease risk factor was smoking in 20 persons (in 6--more then 20 cigarettes daily). 24-hours Holter monitoring revealed single supraventricular complexes in 9 persons (34.7%). We found ventricular arrhythmias in 6 persons (15.8%): 4 (10.5%) had single, unifocal ventricular complexes, 1 (2.6%) had more (up to 6 in one minute) ventricular complexes, and 1 (2.6%) had some ventricular couplets. We observed no ventricular arrhythmias in stress ECG. We conclude, that in apparently healthy subjects with FT the frequency of ventricular arrhythmias is not higher, then in the normal healthy population.

Adolescent↗
PubMed1991

Blood selenium concentrations and glutathione peroxidase activities in patients with breast cancer and with advanced gastrointestinal cancer.

Recent prospective epidemiological studies have shown an association between a low prediagnostic serum selenium (Se) concentration and the risk of cancer. Se concentrations in whole blood and plasma, and the activity of red cell and plasma glutathione peroxidase (GSH-Px) were measured in patients with breast cancer, gastric cancer and colorectal cancer. The observed whole blood and plasma Se concentrations of healthy persons were 99.5 and 78.5 micrograms/L, respectively. Red cell and plasma GSH-Px activities of this group were: 21.0 U/g Hb and 256 U/L plasma. In all investigated cancer patients significantly lower whole blood and plasma Se concentrations, and significantly lower red cell and plasma GSH-Px activities were found, as compared with the values of healthy controls. Low Se concentrations of blood components may be indicative of increased cancer risk.

Adult↗
PubMed1990

On the behavior of instantaneous frequency estimators implemented on Doppler flow imagers.

Analytical and experimental results have been used to examine the behavior of the "autocorrelator" or instantaneous frequency detector (IFD) applied to color-coded Doppler flow mapping. Two effects were studied. The first was the influence of noise, as modified by a stationary echo canceler, on the Doppler frequency detector. Our theoretical considerations predict that uncorrelated input noise signals become partially correlated after cancellation, and bias the response to flow signals. This effect was confirmed by experiment. The canceler introduces a constant negative bias into the denominator of the algorithm implemented by the estimator, thus changing the indicated frequency. The second phenomenon, examined through processing computer simulated Doppler signals added to real noise, is related to the possible ambiguity, called aliasing, of measurements of the mean frequency for wide-band Doppler spectra. We show that aliasing cannot be observed with these spectra unless the signal is first processed by a canceler. Thus, regions of apparent reversed flow direction on two-dimensional flow images of turbulence must usually be due to real reversal of the flow direction.

Algorithms↗
PubMed1989

Bias and variance in the estimate of the Doppler frequency induced by a wall motion filter.

In pulsed Doppler flowmeters, processing of the Doppler signals is often done digitally. The first step in the analysis of the echoes is the filtering which is needed to remove stationary components and low frequency shifts induced by wall motion. This preliminary step is of utmost importance. The influence of uncorrelated noise on the measurement of Doppler signals at the input of this filter is analysed. The frequencies of the Doppler signals are extracted by an algorithm based on correlation techniques. We observed that the filter induces a correlated noise term, which results in an overestimation of the frequency. An effect similar to frequency aliasing may appear. The level of the bias is dependent on filter characteristics and noise level. Our study was carried out on simulated Doppler signals using first and second order filters. An especially desirable solution in flow mapping is proposed in order to decrease this error.

Algorithms↗
PubMed1989

Detection of wall vibrations by means of cepstrum analysis.

Preliminary studies on the usefulness of the cepstrum analysis of Doppler signals for detecting vibrations of periodically vibrating structures, such as aortic valves in children with innocent heart murmurs, were carried out in two stages. First, by cepstrum analysis of computer simulated frequency modulated signals, and second, by the analysis of real Doppler signals generated by a vibrating reflector. Simulation and experimental studies were performed for modulating frequencies from 10 Hz to 60 Hz while changing the amplitude of vibrations from 0.2 mm to 1 mm. The striking similarity between computed cepstra for simulated and for real Doppler signals encouraged further studies in patients. Cepstra computed from two Doppler recordings in children with weak innocent vibratory heart murmurs showed characteristic cepstral lines for modulating frequencies at 21 Hz and 30 Hz in the first and second child, respectively, which were interpreted as the vibration frequencies of the aortic valve leaflets.

Aortic Valve↗