[en] This research consists of two parts. In one part irradiation was used to determine the radiosensitivity of prenatal female germ cells. Mice were given 18 rads of ⁶⁰Co γ-radiation (l rad/min) at various times in utero. The effect of this treatment was measured by light microscopic enumeration of unilaminar follicles remaining in the ovary at 49 days after birth. Greatest sensitivity was seen for irradiation on day 11 post conception. However the germ cells at this period were not as sensitive as are dictyate oocytes of the juvenile mouse. The other part of this study involved γ-irradiation of 14-day-old female mice. Electron microscopy was used to examine the ultra-structural changes taking place in the dictyate oocyte as a response to the radiation. Among the observed changes were irregular nuclear shape, nuclear membrane swelling, chromatin clumping, increased numbers of lysosomes and enlarged lysosomal areas. The significance and degree of these changes are discussed

[en] Short communications only

[en] This study was made to investigate the ultrastructural changes of the male mouse(ICR strain) kidney tissue affected by lead(Pb). Pb, as a form of Pb(CH₃COO)₂ was injected within the peritoneal cavity at the time interval of 24 hrs, 48 hrs and 72 hrs from injection time. In the meantime, electron microscopy was used to investigate the histologic changes occured in control animals, experimental animals. In kidney cells of experimental animals, changes of the nuclear chromatin were little, but cristae of mitochondria presented in cytoplasm was impaired, vacuolation was risen, thoseby many vacuole was formed. Especially, in the case of 5 mg/kg and 10 mg/kg Pb concentration, mitochondrial presented in cytoplasm was considerably deformed. While, with 20 mg/kg of Pb(CH₃C00)₂, it was observed that normal structure was presented in the nucleus electrodensity in cytoplasm was decreased mostly, but mitochondrial deform was slightly decreased. (Author)

[en] Purpose: To analyze locoregional deformation patterns indicative of contact areas in patellar cartilage after different loading exercises. Materials and Methods: 7 healthy patellae were examined in-vivo before and immediately after standardized loading (kneeling, squatting or knee bends) and after 90 minutes of rest using a sagittal 3D-T1-w FLASH WE sequence (22 msec/ 9.8msec/ 15 / 0.3 x 0.3 x 1.5 mm³) at 3 T. After cartilage segmentation and 3D reconstruction, voxel-based and global precision errors (PR) were calculated. The former were used to determine significant differences in local cartilage thickness. Voxel-based 2σ-thickness difference maps were calculated to visualize locoregional deformation patterns. Global changes in volume (Vol), mean thickness (mTh) and cartilage-bone-interface area (CBIA) were calculated. Results: The voxel-based PR depended on cartilage thickness (D) ranging from 0.12 - 0.35 mm. For D ≥ 1 mm the RF was < 0.31 mm (< voxel size), and for D ≥ 2 mm, the RF was < 0.22 mm. The global PR was 83 mm³ (2.4 %) for Vol, 0.06 mm (2.0 %) for mTh and 16 mm² (1.4 %) for CBIA. The focal cartilage deformation equaled 14 % of the local thickness reduction. The deformation areas were oval and located in the peripheral medial (more vertically oriented, all exercises) and caudo-lateral (more horizontally oriented, kneeling and knee bends) aspects of the patella and were least pronounced in knee bends. Significant changes for Vol/mTh ranged from 2.1 to 3.7 %. Conclusion: This MRI-based study is the first to identify in-vivo voxel-based patellar cartilage deformation patterns indicating contact and loading zones after kneeling and squatting. These zones are anatomically and functionally plausible and may represent areas where stress induced degeneration and subsequent OA can originate. The data may facilitate understanding of individual knee loading properties and help to improve and validate biomechanical models for the knee. (orig.)

No abstract available

[en] Magnetic resonance (MR) diffusion-weighted imaging (DWI), dynamic susceptibility contrast-enhanced perfusion imaging (DSC), and MR spectroscopy (MRS) techniques provide specific physiologic information that may distinguish malignant glioma progression from post-radiation change, yet no single technique is completely reliable. We propose a simple, multiparametric scoring system to improve diagnostic accuracy beyond that of each technique alone. Fifteen subjects with lesions suspicious for glioma progression following radiation therapy who had also undergone 3-tesla DWI, DSC, and MRS studies of the lesion were retrospectively reviewed. Minimum apparent diffusion coefficient (ADC) ratio, maximum regional cerebral blood volume (rCBV) ratio, and maximum MRS choline/creatine (Cho/Cr) and choline/N-acetyl-aspartate (Cho/NAA) metabolic peak-height ratios were quantified within each lesion. Each parameter (ADC ratio, rCBV ratio, and combined Cho/Cr and Cho/NAA ratios) was scored as either glioma progression (one point) or radiation change (zero point) based upon thresholds derived from our own data. For each lesion, the combined parameters yielded a multiparametric score (0 to 3) for prediction of tumor progression or post-radiation change. Optimum thresholds for ADC ratio (1.30), rCBV ratio (2.10), and either combined Cho/Cr (1.29) and Cho/NAA (1.06) yielded diagnostic accuracies of 86.7%, 86.7%, and 84.6%, respectively (p < 0.05). A combined multiparametric score threshold of 2 improved diagnostic accuracy to 93.3% (p < 0.05). In this small series combining 3-T DWI, DSC, and MRS diagnostic results using a simple, multiparametric scoring system has potential to improve overall diagnostic accuracy in distinguishing glioma progression from post-radiation change beyond that of each technique alone. (orig.)

[en] Short note

No abstract available

[en] Our aim was to relate MRI findings in patients with severe traumatic brain injury (TBI) to clinical severity and long-term outcome. We studied 37 patients with severe TBI, who were submitted to clinical assessment for disability and cognition and to MRI 60-90 days after trauma. Clinical assessment was also performed 3, 6 and 12 months later. The number and volume of lesions in various cerebral structures were calculated semiautomatically from FLAIR and fast field-echo images. Possible correlations between total and regional lesion volume and clinical deficits were then investigated. The frontal and temporal lobes were most frequently involved. Total lesion volume on FLAIR images correlated significantly with clinical outcome, whereas that on FFE images did not. Regional analysis showed that FLAIR lesion volume in the corpus callosum correlated significantly with scores on disability and cognition scales at the first clinical assessment. FLAIR lesion volume in the frontal lobes correlated significantly with clinical scores 1 year later. (orig.)

[en] Exposure of lambda phage to triplet acetone, generated during the aerobic oxidation of isobutanal by peroxidase, leads to genome lesions. The majority of these lesions are detected as DNA single-strand breaks only in alkaline conditions, so true breaks were not observed. Also, no sites sensitive to UV-endonuclease from Micrococcus luteus were found in DNA from treated phage. The participation of triplet acetone in the generation of such DNA damage is discussed. (Author)