Biomedical subjects

C Czerny

Publications and source records attributed to C Czerny.

82 records · Page 5Linked to original sources

PubMed1996

Lesions of the acetabular labrum: accuracy of MR imaging and MR arthrography in detection and staging.

PURPOSE: To determine the accuracy of magnetic resonance (MR) imaging and MR arthrography in the detection and staging of lesions of the acetabular labrum. MATERIALS AND METHODS: Fifty-seven hips of 56 patients with chronic hip pain and a strong clinical suspicion of labral lesions were examined with a three-dimensional gradient-echo sequence in the coronal oblique and sagittal oblique projections before and after the intraarticular injection of gadopentetate dimeglumine. The labra were evaluated on the basis of morphology, signal intensity, the presence or absence of a tear, and their attachment to the acetabulum. Twenty-two of the hips underwent surgical intervention, and 35 hips were treated conservatively. RESULTS: Twenty of the 22 labra with surgical proof were staged accurately with MR arthrography. On the conventional MR images, only eight of the 22 labra were staged correctly. Whereas the sensitivity of MR arthrography was 90% and its accuracy was 91%, the sensitivity of MR imaging was 30% and its accuracy was 36%, compared with surgical findings. CONCLUSION: MR arthrography enables accurate detection and staging of lesions of the acetabular labrum and appears to be indicated in the assessment of chronic hip pain in patients with a strong suspicion of labral lesions.

Acetabulum↗

PubMed1996

Correlations between anatomic and MRI sections of human cadaver temporomandibular joints in the coronal and sagittal planes.

Cadaver material was used in this study to correlate sequential sagittal and coronal T1-weighted magnetic resonance images against anatomic detail. Magnetic resonance imaging (MRI) was found to accurately represent soft tissues in normal and deranged joints. In contrast to previous reports, MRI was found to accurately represent the discal-retrodiscal junction and did not appear to give false positive findings for disc displacement. Magnetic resonance imaging provided good images of bony outline, particularly in coronal views. Difficulties in interpretation arose when different adjoining tissues produced the same MR image; the central tendon of the lateral pterygoid muscle can appear as an extension of the disc, imaging as a distorted and displaced disc. In anatomic sections, a medial hernia sac in the lower joint space was seen as a constant indicator of the medial component of disc displacement; however, this was not evident in sagittal and coronal T1-weighted images. Fibrocartilaginous remodeling of the articular surface projecting into a discal perforation presented the same image as normal discal tissue. Because discs are often thinned over the lateral pole, it is difficult to determine whether discal tissue is present between the articular surfaces when MRI is at its present resolution. Subcortical bone spaces may be misinterpreted as areas of avascular necrosis and osteochondritis dissecans. It is recommended that an imaging sequence of the TMJ include a midcondyle image and lateral, central, and medial sagittal images; however, the lateral sagittal image is the most difficult to interpret.

Adult↗

PubMed1995

Rheumatoid arthritis of the craniocervical region by MR imaging: detection and characterization.

OBJECTIVE: The purpose of our study was to evaluate the potential of contrast-enhanced MR imaging to detect and to characterize craniocervical rheumatoid arthritis in a large population group, to compare MR imaging with clinical and conventional radiographic findings, and to examine the relationship between the histopathologic and MR imaging findings in seven patients. SUBJECTS AND METHODS: We performed contrast-enhanced MR imaging using T2-weighted gradient-echo sequences and T1-weighted spin-echo sequences in 136 patients with rheumatoid arthritis. Sequential T1-weighted images were obtained before, 3 min after, and 15 min after injection of contrast material. Plain films were acquired in all patients. Serologic status and neurologic status were determined in each patient within 2 days of MR imaging. Patients were categorized into one of four groups, depending upon whether they had joint effusion, hypervascular pannus, hypovascular pannus, or fibrous pannus according to signal patterns on contrast-enhanced MR images. Signal intensity was measured to assess the enhancement of synovial hypertrophy, joint capsule, joint effusion, and the various stages of pannus tissue. Histologic specimens were obtained from seven patients and were correlated with MR imaging findings. RESULTS: Acute and chronic synovitis were differentiated with contrast-enhanced MR imaging as follows: joint effusion (n = 29), hypervascular pannus (n = 54), hypovascular pannus tissue (n = 8), and fibrous pannus (n = 22). Signal intensity differed significantly among the four groups on contrast-enhanced T1-weighted images. In 59 patients with effusion or hypervascular pannus tissue, atlantoaxial subluxation was diagnosed with plain films. Patients with negative findings on radiographic studies (n = 20) had joint effusion, hypervascular pannus tissue, hypovascular pannus formation, or fibrous pannus tissue on MR imaging studies. Cord compression was found in 10% of all cases and isolated sac compression in 16%. Neurologic findings showed no correlation with MR imaging features. CONCLUSION: Contrast-enhanced T1-weighted spin-echo MR imaging can discriminate between joint effusion and various forms of pannus in patients with rheumatoid arthritis of the craniocervical region. MR imaging also can detect joint effusion and pannus tissue in patients with negative radiographic findings. No relationship between MR imaging findings and clinical symptoms were found. Tissue enhancement and histopathologic findings correlated in a limited number of autopsies.

Acute Disease↗

PubMed1994

Maintenance of clonal anergy by endogenously produced IL-10.

Inadequate co-stimulation of tumor reactive T cells may contribute to the fact that antigenic tumors are not normally rejected by the immune system. We recently reported that the induction of profound unresponsiveness in a T cell clone by melanoma cells expressing MHC class II antigens may provide a mechanism for these tumor cells to escape immunosurveillance. Here we demonstrate that two T cell clones (sTC3 and sTS5) produced high amounts of IL-10 after being rendered anergic by autologous melanoma cells. Co-culture of these T cell clones with melanoma cell transfectants expressing B7, which failed to induce anergy, resulted in a significantly lower production of IL-10. IL-10 production by the anergic T cell clones correlated with an impaired ability to produce IL-2 in response to TCR mediated activation. Neutralization of IL-10 reduced the duration of T cell unresponsiveness from 14 to only 4 days, but inhibition of IL-10 production during initiation of anergy showed no effect on it. Induction of the unresponsive state, as well as the subsequent IL-10 production in sTC3 cells, could be prevented by the addition of cyclosporin A to the primary co-culture of sTC3 and the autologous melanoma. Taken together, these results indicate that IL-10 is important for maintenance of T cell anergy induced by contact with nonprofessional antigen presenting cells such as MHC class II+ melanoma cells. Furthermore, we were able to detect IL-10 in serum from melanoma patients and IL-10 mRNA in tumor infiltrating lymphocytes isolated from melanoma metastases, suggesting an in vivo relevance of our in vitro findings.

Base Sequence↗

PubMed1994

Hypermutable ligation of plasmid DNA ends in cells from patients with Werner syndrome.

Werner Syndrome is a rare autosomal recessive disorder characterized by an increased cancer risk and by symptoms suggestive of premature aging. Cells from these patients demonstrate a typical pattern of chromosomal instability and a spontaneous hypermutability with a high rate of unusually large deletions. We have studied the in vivo DNA ligation in three lymphoblast cell lines from Werner syndrome patients and three from normal donors. In our host cell ligation assay we transfected linearized plasmid pZ189 and measured the amount of plasmid DNA ends rejoined by these host cells as the ability of the recovered plasmid to transform bacteria. A mutagenesis marker gene close to the ligation site allowed screening for mutations. Subsequent mutation analysis provided information about the accuracy of the ligation process. The cells from Werner syndrome patients were as effective as normal cells in ligating DNA ends. However, mutation analysis revealed that the three Werner syndrome cell lines introduced 2.4-4.6 times more mutations (p < 0.001) than the normal cell lines during ligation of the DNA ends: the mutation rates were 69.4, 97.2, and 58.7%, as compared to 23.6, 21.7, and 24.4% in the normal cell lines. These increased mutation frequencies in plasmids ligated during passage through Werner syndrome cells were mainly due to a significant (p < 0.001) increase in deletions. This error-prone DNA ligation might be responsible for the spontaneous hypermutability and the genomic instability in Werner syndrome cells and related to the apparently accelerated aging and high cancer risk in affected patients.

Cell Line↗

PubMed1994

[Rheumatoid arthritis of the craniocervical transition. Detection of inflammatory changes in contrast CT and MRI].

A total of 136 patients with rheumatoid arthritis underwent MRI with sagittal T1-weighted spin echo sequences before and after i.v. administration of Gd-DTPA and with a 15-min delay. In addition, T2-weighted gradient echo sequences were performed. Conventional radiographs, including tomography in sagittal and a.p. planes, were also taken of all patients; 51 were also examined by CT before and after i.v. administration of contrast medium and in addition with a 15-min delayed series. The signal intensities of MRI and the changes in density caused by contrast uptake on CT were examined visually and measured quantitatively. The inflammatory changes were classified in four phases by the MRI and CT findings and histological results. A correlation (p < 0.05) was found with the erythrocyte sedimentation rate. MRI was superior to CT in 10% of cases. A discrete effusion in the anterior junction was missed in 4 cases and a hypervascular pannus formation in 1 case by CT. The CT was superior to the other methods in detecting bony lesions and calcifications in the atlantödental region. The local activity of the inflammatory changes can be graded by classifying them with contrast-enhanced MRI and CT, which yield an exact result for better monitoring during therapy.

Adolescent↗

PubMed1993

Tumor escape mechanisms from immunosurveillance: induction of unresponsiveness in a specific MHC-restricted CD4+ human T cell clone by the autologous MHC class II+ melanoma.

The co-existence of tumor specific immunity with a progressing tumor is observed in a variety of experimental systems and remains one of the major paradoxes of tumor immunology. We now report that a human melanoma cell line (SMC) expressing MHC class II was able to induce clonal anergy in a specific, MHC-restricted CD4+ T cell clone (STC3). Clonal anergy is a mechanism of T lymphocyte tolerance induced by antigen receptor stimulation in the absence of co-stimulation. We observed that a CD4+ T cell clone and an autologous melanoma cell line form conjugates with each other that leads to an increase of [Ca++]i in the T cell clone; however, this interaction failed to induce IL-2 production or proliferation of the T cell clone. Furthermore, this interaction rendered this T cell clone unresponsive to subsequent stimulation. All these effects were MHC class II restricted. Therefore, the human melanoma cell line SMC was capable of delivering antigen-specific signals to the T cell clone, but did not deliver the co-stimulatory signals, e.g. a B7/CD28 interaction, necessary for full T cell activation. Transfection of the melanoma cells with an expression vector containing a B7 cDNA that resulted in subsequent expression of B7 on its cell surface rendered it into a fully competent antigen presenting cell, which is able to induce a nuclear factor binding to the IL-2 promoter in the specific T cell clone resulting in enhanced IL-2 transcription, synthesis, and T cell proliferation. These findings suggest that manipulation of co-stimulation may offer new strategies for future tumor immunotherapy.

Base Sequence↗

PubMed1992

[Magnetic resonance tomography in pulmonary hypertension].

We examined 23 patients with pulmonary hypertension of varying aetiology by MRI and compared the results with those of right heart catheterisation. The best correlation was obtained between right ventricular mural thickness and mean pulmonary pressure (R = 0.91, p = 0.001). There was significant correlation (R = 0.85, p = 0.001) for the diameter of the inferior vena cava, which was dilated in all patients with pulmonary hypertension. There was no significant correlation between mean pulmonary pressure and the diameters of the superior vena cava or the main pulmonary artery branches (R = 0.55 and 0.75 respectively, p less than 0.05). Amongst functional measurements there was a correlation between right ventricular ejection fraction and mean pulmonary artery pressure (R = 0.71, p = 0.001). There was no correlation between right ventricular end-systolic and end-diastolic volume. In all patients with pulmonary hypertension, dynamic flow sensitive gradient echo sequences showed the presence of tricuspid insufficiency. A further semiquantitative criterion for the presence of pulmonary hypertension in 4 patients (17%) was an abnormal signal from the main pulmonary artery in early to mid-systole shown on T1-weighted transverse sections.

Adult↗

PubMed1989

[Experimental detection of the paraspecific effects of purified and inactivated poxviruses].

The paraspecific effect of pox viruses i.e. stimulation of the nonspecific part of the complex immune system, was demonstrated in vitro and in vivo for 3 different types of virus (vaccinia virus, avipox virus, parapox virus). By means of purification, concentration and inactivation, it was possible to prove that the paraspecific effect is brought about by the pox virus particle per se. The effect is induced by certain epitopes in the complex structure of the virus and is independent of virus multiplication. Both purified pox viruses and inactivated, purified pox viruses stimulate NK cell activity, the CSA and the formation of interferon, and reach higher efficacy indices in a challenge test with baby mice using stomatitis vesicularis virus than non-purified and non-inactivated cell culture material. The degree of purity of the pox virus preparations was established using the electron microscope and monoclonal antibodies. The purified and concentrated pox virus preparations proved to be pyrogen-free; they were not toxic to baby mice in vivo. An endotoxin-induced effect could be ruled out. The broad paraspecific effect of pox viruses and their structural components lends itself to use as paramunity inducers in prophylaxis and therapy.

Animals↗

PubMedDate not supplied

Dental MR tomography of the mandible.

Imaging of the jaw bones is routinely achieved by conventional X-ray tomography or CT. In this study a new imaging procedure (dental MR tomography) is introduced. Five subjects were positioned in the standard neck coil of a 1.0 T MR scanner, and T1- and T2-weighted imaging of the mandible was performed in the axial plane. After the examination, the data were reconstructed as panorama and cross-sectional images using a software package for dental imaging on a workstation. The neurovascular bundle within the mandibular canal (MC), its relation to the teeth, and the pulp chambers of the teeth were demonstrated excellently in all cases. Edema and reactive hypervascularization due to an inflammatory process were also well visible. Dental MR tomography could become a good alternative to X-ray-based imaging modalities of the jaw bones by additionally offering the advantage of directly imaging the neurovascular bundle within the MC. Furthermore, administration of contrast agent for differentiation of pathological alterations is possible.

Adult↗