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Biomedical subjects

D Novak

Publications and source records attributed to D Novak.

At least 19 recordsLinked to original sources
PubMed1997

Diagnostic value of MR imaging in comparison to CT in the detection and differential diagnosis of renal masses: ROC analysis.

The aim of this work was to compare MR imaging and CT in the detection of renal masses and in the differential diagnosis between benign and malignant lesions. In 33 patients with 54 renal lesions CT and MR images were evaluated by four readers with regard to tumor detection and characterization using a receiver-operating-characteristics (ROC) analysis. The MRI protocol consisted of a T1-weighted spin-echo (SE) sequence (TR/TE: 300/10 ms) before and after contrast administration and a heavily T2-weighted turbo-SE (TSE) sequence (TR/TE: 5500/150 ms). Az values for the area under the ROC curves for lesion detection were 0.92 +/- 0.04 for CT and 0.91 +/- 0.05 for MRI, respectively, which was not statistically different. The MRI technique was slightly, but not significantly, better than CT in the overall characterization (accuracy in differentiation between benign and malignant) of renal lesions with an Az value of 0.90 +/- 0.05 compared with 0.88 +/- 0.06 for CT. The MRI technique proved to be statistically superior to CT (p < 0.01) in the correct characterization of benign renal lesions. MRI equals CT in the overall detection and differential diagnosis of renal masses. MRI is very helpful for further differential diagnosis of lesions which are equivocal on CT especially in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinoma.

Adult↗
PubMed1996

[Magnetic resonance tomography of the kidney: the testing of new pulse sequences and comparison with CT in the differential diagnosis of space-occupying lesions].

PURPOSE: To evaluate new pulse sequences (turbo-spin-echo [TSE] and turbo-field-echo [TFE] sequences) for study protocol optimisation and to assess the role of MRI in the differential diagnosis of renal tumours. METHODS: In six volunteers MRI of the kidney was performed at 0.5 T using a conventional T2 weighted spin-echo (SE) sequence (TR/TE 1800/90 ms) and three different TSE sequences (TR 1800-5000 ms, TE 90-150 ms). Additionally CT and MRI was performed in 34 patients with 41 renal masses. Two readers evaluated both images regarding the differentiation between malignant and benign masses. RESULTS: The pilot study showed that the heavily T2-weighted TSE sequence (TR/TE 5500/150 ms) was superior to other sequences with regard to image quality and differentiation of the corticomedullary junction. In the clinical study malignant tumours were correctly classified with CT and MRI in 86.4% and 95.5% of the cases, whereas the accuracy in the diagnosis of benign lesions of CT and MRI was 73.7% and 89.5%, respectively. CONCLUSION: Using new puls sequences MRI is superior to CT in the differential diagnosis of renal tumours. MRI is superior to CT in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinomas.

Diagnosis, Differential↗
PubMed1996

Effective doses due to external irradiation from the Chernobyl accident for different population groups of Ukraine.

A model for the external exposure of the Ukrainian population after the Chernobyl accident was developed. It is based on extensive measurements of external gamma-exposure rates (EGER) in air and of external effective doses of members of five population groups. Questionnaires were used to determine the occupancy times of members of the population groups at three types of locations; inside houses, outdoors, and outside of the home settlement. Behavior factors are defined as the ratio of individual external doses to a reference dose for a phantom standing permanently over an open field with the same average 137Cs activity per unit area as in the settlement. The behavior factors were derived for five population groups (children younger than seven years, the age group from eight to seventeen years, employees, agricultural workers, and pensioners) by two methods: first from direct measurements of individual doses by thermoluminescent dosimetry and an experimental determination of the average 137Cs activity per unit area in the settlement of interest; and second from external gamma-exposure rates in air at various types of locations and from the questionnaire data. The methods were found to be consistent and the results were used to calculate external exposures of the five population groups in the years 1987 through 1991.

Adult↗
PubMed1994

Evaluation of RapiDEC Staph for identification of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus saprophyticus.

RapiDEC Staph is a test for presumptive identification of the principal human staphylococcal species, Staphylococcus aureus, S. epidermidis, and S. saprophyticus. The test includes control and test cupules for fluorogenic detection of coagulase and chromogenic substrates for alkaline phosphatase and beta-galactosidase. These tests identify S. aureus, S. epidermidis, and S. saprophyticus, respectively. Positive results with both chromogenic substrates provide a presumptive identification of S. xylosus or S. intermedius (S. xylosus-S. intermedius). Test cupules are inoculated with an organism suspension, and reactions are read after a 2-h incubation. RapiDEC-Staph was evaluated with 303 clinical and stock staphylococcal strains. Identifications were compared with those obtained by the tube coagulase test, a latex slide coagulase test (StaphAUREX), another commercial identification system (Staph-TRAC), and additional conventional tests. RapiDEC-Staph correctly identified 100% of 130 S. aureus strains, 70.3% of 74 S. epidermidis strains, and 81.3% of 32 S. saprophyticus strains. Four of five S. xylosus isolates were called S. xylosus-S. intermedius. Unidentified S. epidermidis and S. saprophyticus strains were called "Staphylococcus spp." Among the 62 other coagulase-negative staphylococci, 4 were misidentified as S. epidermidis and 7 were misidentified as S. saprophyticus. While the sensitivity and specificity of the fluorogenic coagulase test for S. aureus were 100%, failure to detect alkaline phosphatase activity in several S. epidermidis isolates resulted in fewer correct identifications by the RapiDEC-Staph test for this species.

Alkaline Phosphatase↗
PubMed1993

Immunocytochemical reactivity of a mouse monoclonal antibody CDI 315B raised against human breast carcinoma.

Our previous report revealed the production of monoclonal antibody (MoAb) CDI 315B by immunization of mice with tumor extract proteins of human invasive ductal breast carcinoma. In the present study we report on the immunocytochemical reactivity of this MoAb with formalin or methacarn fixed, paraffin embedded tissue sections and also with cell cultures. Among breast tissues, positive staining was detected in 88% (64 of 73) of primary breast carcinomas, 77% (7 of 9) of metastatic lymph nodes, 24% (8 of 33) of benign breast disease and 15% (2 of 13) of normal breast tissue. No immunostaining was detected with several other tumors, with the exception of melanoma, where 63% (5 of 8) of positive staining was found. On in vitro cell lines, positive reaction was detected only with breast carcinoma and melanoma cells, but not with other examined cell lines. On benign breast disease tissue sections, positive reaction was detected in areas with cell hyperplasia. On normal breast tissue sections MoAb 315B stained the epithelial cells of terminal ductuli. Since the MoAb 315B recognized some antigen present in the cytoplasm of most breast carcinoma cells, this MoAb may have potential application in diagnosis and management of breast cancer.

Adenofibroma↗
PubMed1992

Developmental changes in hepatic basolateral membrane lipid composition and fluidity.

Membrane fluidity and lipid composition influence the activity of a variety of membrane proteins. Decreased rates of hepatic ion clearance are associated with the neonatal period. We postulated that hepatic basolateral membranes derived from suckling animals might be less fluid than those from adult animals. Basolateral membrane vesicles were prepared from the livers of 1-week-old (SBLMV) and adult (ABLMV) rats by a Percoll gradient method. Na+/K(+)-ATPase activities were similar in the two groups. Double bond index, cholesterol and cholesterol/phosphorus ratios were significantly higher in SBLMV compared with ABLMV, while lipid phosphorus and relative percentages of phospholipid subclasses did not differ. Fluorescence anisotropy measured using diphenylhexatriene as well as 2-(9-anthroyloxy)stearate was significantly greater in SBLMV compared with ABLMV, while measurements made with 12-(9-anthroyloxy)stearate were similar in both age groups. Mean excited state lifetimes, lifetime distributions, and rotational correlation times were similar in both groups. These data suggest that hepatic basolateral membranes derived from suckling rats are less fluid than those from adult animals and further suggest that this difference may be due to increased cholesterol in hepatic basolateral membranes derived from suckling animals.

Animals↗
PubMed1991

Immunological studies of the toxic site in ammodytoxin A.

Two monoclonal antibodies against the native ammodytoxin A and four site-directed polyclonal antibodies against synthetic peptides derived from the primary structure of the toxin were prepared in order to estimate the localization of its toxic site. Some of the antibodies neutralized the lethal toxicity of the toxin, thus indicating an approximate position of the toxic or receptor binding site on the molecule that is different from those predicted by comparison with a number of known sequences.

Amino Acid Sequence↗
PubMed1991

The influence of mouse sera, regenerating liver extracts and bacterial products on the abilities of different cells in vitro.

In the complexity of host tumor relations, the regeneration of the tissue in which the tumor is growing, or in some other tissue in the organism, could influence the maturation of tumor cells, i.e. tumor reversion. Clinical observations and experiments on plants, lower animals, or animal embryos, performed by several authors, and our results on the influence of regenerating mouse liver on the abilities of tumor transplanted there or elsewhere in the organism led us to study the in vitro growth of different cells or bacteria exposed to the extracts of normal or regenerating liver and/or sera from these animals. Further, sterile used bacterial media were added to bacterial or cell cultures, respectively. Depending on the model, liver extracts-particularly extracts and sera from mice with regenerating liver-were shown to inhibit radioactive thymidine incorporation in the cells. In these experiments, the number of bacteria or cells per culture was lower than in otherwise treated corresponding cultures. Further, used sterile media of bacterial cultures stimulated the growth of bacteria but inhibited thymidine incorporation into fibrosarcoma cells in vitro. Whether this means that one or several common regulators exist in nature appears as an intriguing, but still completely open question. The idea of controlling tumor growth by using such regulatory growth factors seems very provocative.

Animals↗
PubMed1989

[Anti-RANA antibodies and rheumatoid arthritis].

Anti RANA antibodies were determined by the method of indirect immunofluorescence in 51 patients with the classic resp. definitive form of rheumatoid arthritis (ARA) and in 19 healthy persons. Anti RANA antibodies were found in 92% of the patients with rheumatoid arthritis and in 16% of the control group. The reactive nuclear antigen is present in human B lymphocyte tissue cell cultures transformed by the EPSTEIN-BARR virus--Raji cells. The anti RANA antibody test is very suitable for use in the diagnosis of rheumatoid arthritis.

Antibodies, Antinuclear↗
PubMed1988

Evaluation of a gerontological nursing continuing education programme: effect on nurses' knowledge and attitudes and on patients' perceptions and satisfaction.

The purpose of this study was to evaluate the effects of a four-session (8-hour) gerontological nursing continuing education (CE) programme on nurses' knowlege of and attitudes towards the elderly. The study also sought to ascertain the effects of the CE programme on patient satisfaction with and perceptions of nursing care. Seventy-six nurses completed the Miller-Dodder Revision of the Palmore Facts on Ageing Quiz and the Kogan Attitudes Towards Old People Scale before and after participating in the CE programme. Post-test scores on both measures were slightly but significantly higher than pretest scores. Thirty hospitalized elderly patients were interviewed before and 33 were interviewed after the CE programme was offered to the nurses on their hospital units, using the LaMonica-Oberst Patient Satisfaction Scale and the Harrison-Novak Patient Perception Scale. Post-test measures of patient satisfaction and perception were not significantly different from pretest scores. Patients were generally satisfied with their nursing care, but perceived that nurses did not focus on health promotion activities. In addition, 59% of the patients indicated that they were unable to distinguish nurses from other health care providers. The article identifies implications of the study for nursing education, practice and research.

Aged↗
PubMed1983

Applicability of liquid radiopaque polyurethane for transcatheter embolization.

Polyurethane Bayer was tested as an occlusive agent for experimental embolization in postmortem and postnephrectomy kidneys which served as a tumor model. Coaxial and balloon catheters were used for the embolization. To make polyurethane radiopaque, the material was labeled with different water-soluble, oily and solid contrast agents. Best results were achieved with oily contrast materials, e.g., Pantopaque. We found that polyurethane can easily be injected during a predetermined working time of 8-10 min. The embolization results in a complete, permanent, and homogeneous occlusion of the proximal arterial branches and small peripheral vessels.

Embolization, Therapeutic↗
PubMed1983

Indications for and comparative diagnostic value of combined ultrasound and X-ray mammography.

A standardised method of ultrasound mammography is described. In order to achieve the same position, form, and shape of the breast as during röntgen mammography a Lucite plate in horizontal, and vertical position is used. Ultrasound contact scanning of the whole breast is carried out in cranio-caudal as well as in medio-lateral direction of the ultrasound beam. Ultrasound scanning is performed with the compression of the breast corresponding to the compression during röntgen mammography. It was found that the ultrasound breast examination combined with X-ray mammography optimizes the differentiation benign and malignant masses and therefore may reduce the incidence of breast biopsy. A combined use of both examination modalities in the evaluation of the breast is advocated.

Abscess↗
PubMed1981

[The value of angiography, sonography and computed tomography in follow-up studies after palliative renal tumour embolization (author's transl)].

Palliative transcatheter tumour embolization was performed in 40 patients having non-operable renal carcinoma using particulate, semiliquid and liquid embolizing substances. In addition the Gianturco-Andersen-Wallace (GAW) coil was applied in 7 patients showing remarkable vascular recanalization. Effects of the angiotherapeutic procedures were controlled by re-angiography in 33 cases. Sonography was performed in 15 cases and computed tomography in 24 patients before and after embolization. It was found that the re-angiography was necessary: a) as thhe first control to prove the extension of thrombotic obstruction and to assess the remaining collateral circulation; b) as an indication for re-embolization in 7 cases showing remarkable recanalization. Follow-up computed tomography and sonography helped to observe the long-term changes: shrinkage of the tumour and the embolized kidney, and recurrence of the tumor growth or local retroperitoneal and liver metastases. The analysis of our observations confirms the value of re-angiography for the short-term follow-up study. Sonography and computed tomography are reliable procedures for the further follow-up of patients.

Adenocarcinoma↗