Oscillatory Cs-137 Distribution Pattern in Scotch Pine Bark.

The vertical distribution of the anthropogenic radionuclide Cs-137 in the Scots pine (Pinus sylvestris L.) bark was studied in two model trees in the radioactive contamination zone of the Bryansk region. Each tree was divided into 10-cm bars from the trunk base to a length of 17 m, and the bark with the bast was separated from each bar to obtain a separate sample. In addition to Cs-137, the natural radionuclide K-40 was measured in the bark of model tree 2 from the trunk base to a 6.5-m length. Specific activities of Cs-137 and K-40 were measured by γ-ray spectrometry. The vertical distribution of Cs-137 in the bark was for the first time observed to have a wave-like pattern with a period of approximately 1 m. The K-40 distribution showed a similar oscillatory pattern, consistent with a similar mechanism responsible for potassium and cesium behavior in woody plants. The correlation coefficient between specific activities of Cs-137 in model trees 1 and 2 was 0.80; the correlation coefficient between Cs-137 and K-40 activities in model tree 2 was 0.45. Cs-137 was assumed to provide a radiotracer to assess the intake and distribution of chemical elements in Scotch pine tissues. The oscillatory pattern observed for the vertical distributions of cesium and potassium in the pine bark has not been described in the available literature before.

[Radiological Aspects of Transition of Russian Areas Affected by the Chernobyl Accident to Normal Activities].

Dynamics of radiation situation in settlements, agriculture and forestry on the Russian Federation areas af- fected by the Chernobyl accident is presented. A set of challenging problems on public radiation protection and rehabilitation of territories was determined. The main objective at a long-term period after the accident is a stage-wise return of the affected areas to normal activity without any radiological criteria restrictions. For practical realization of this process it is necessary to change the national statutes and regulations consid- ering the contemporary international approaches, to pass to the current exposure situation and to establish reference levels, to define criteria of transition of the areas affected after the Chernobyl accident to normal activity. The change of conceptual approaches will allow one to revise the boundaries of settlement zoning and to develop the regulatory framework on procedures of changing their status from radioactively contami- nated zone to normal activity zone; to develop the regulatory framework on the procedures of transition of agricultural and forest lands classified as radioactively contaminated zones to territories where the traditional husbandry is possible. The Russian Federation has positive experience of transition of areas contaminated as a result of the Chernobyl accident to normal activity.

[Radioecological division of the Russian forests contaminated by radionuclides].

The dependence of trans factor of radionuclides on the soil to the vegetation (wood etc.) caused by natural-climatic conditions determine a duration period of the rehabilitation of ecological and social-economic functions of forests landscapes polluted by radionuclides. It firstly allows to classify forest ecosystems by groups of their radioecological stability with division into three appropriate radioecological districts. The forest ecosystems characterized by a rather short-term duration of the rehabilitation period of ecological and social-economic functions after the radiation contamination (till 30 years) are relatively stable in the radioecological reference. They are typical to steppe and forest-steppe zones and appropriate radiological district (related to natural zone). The forests ecosystems with the intermediate-term rehabilitation period after the radiation impact (30-60 years) are weakly stable in the radioecological reference and typical to broadleaved and coniferous-broadleaved forest zones and appropriate radiological district. The forest ecosystems with a long-term rehabilitation period after the radiation contamination (more than 60 years) are characterized as radioecologically unstable. The appropriate radiological district is include north-taiga forests and pre-tundra open woodlands.

Fluorine-18-fluorodeoxyglucose dual-head gamma camera coincidence imaging of recurrent colorectal carcinoma.

We report our experience with coincidence detection imaging of 18F-fluorodeoxyglucose (FDG) using a dual-head gamma camera. Scanning of the pelvis and abdomen of a patient with recurrent colorectal carcinoma showed recurrent disease in the pelvic floor and the base of the urinary bladder and metastatic disease in the retroperitoneal space of the pelvis. Although the tumor involving the bladder and pelvic floor was detected by CT and magnetic resonance imaging (MRI), metastatic spread to the retroperitoneal nodes on the left side was detected only by 18F-FDG imaging. Based on the ultrasound, CT, MRI and cystoscopy, a local recurrence of cancer was presumed in our patient. An exploratory laparotomy was performed to resect the tumor in its entirety. At the time of surgery, the retroperitoneal metastasis in the pelvis was confirmed. Had the findings of the coincidence detection imaging study been considered, the patient would have been spared the surgical procedure.

Structure and expression of the cytosolic aldehyde dehydrogenase gene in cyclophosphamide-resistant murine leukemia L1210 cells.

These investigations were performed to clarify the molecular basis for the enhanced expression of cytosolic aldehyde dehydrogenase (ALDH-1) enzymatic activity in the cyclophosphamide-resistant L1210/CPA murine leukemia cell line, as compared to the parental L1210/O strain. Western immunoblot analysis was performed using a 15-fold greater quantity of cytosolic protein from the L1210/O as compared to the L1210/CPA cell line. Nevertheless, ALDH-1 immunoreactive protein could be detected only in the L1210/CPA cells. Northern analyses, performed using total cellular and polyadenylated RNA, again demonstrated ALDH-1-specific transcripts only in the L1210/CPA cell line. This transcript was identical in size to the ALDH-1 message expressed by normal murine hepatocytes. On Southern analysis, no evidence of gene amplification, gene rearrangement, or significant mutations of length was detected. These studies suggest that the ALDH-1 protein produced by the L1210/CPA cell line is structurally normal. Moreover, overexpression of the gene does not appear to have arisen as a result of an incremental process, such as gene amplification. Rather, a qualitative abnormality in the regulation of this gene appears to exist in the L1210/CPA cells, which distinguishes them from L1210/O cells and from normal murine lymphocytes.

Levels of p53 protein increase with maturation in human hematopoietic cells.

Transfection of the wild-type p53 gene into malignant cell lines usually results in an inhibition of proliferation. However, the physiological function of the endogenous p53 gene product has been difficult to ascertain. In order to examine whether p53 is involved in the regulation of proliferation and/or differentiation of hematopoietic tissue, we modified a recently developed flow cytometric assay to assess p53 protein expression in normal human hematopoietic cells, primary leukemias, and selected leukemia cell lines. In normal human bone marrow, p53 protein was not detected in the proliferative, progenitor cell populations identified by the cell surface antigens CD34 (progenitor cells of multiple lineages) or glycophorin (erythroid precursors). In contrast, low but detectable levels of p53 protein were observed in the nonproliferative, mature lymphoid, granulocytic, and monocytic cell populations. Similarly, p53 levels increased and DNA synthesis decreased during 12-O-tetradecanoylphorbol-13-acetate-induced differentiation of ML-1 myeloblastic leukemia cells. Both of these results suggest that endogenous, wild-type p53 protein may play a role in hematopoietic cell maturation, possibly by contributing to the inhibition of proliferation that occurs during terminal differentiation. Leukemia cells deviated from this pattern of expression: (a) in contrast to the normal, proliferative bone marrow progenitor cells, a significant percentage of patient leukemia samples expressed detectable levels of p53 protein; and (b) leukemia cell lines exhibited lineage-specific abnormalities in p53 expression, with overexpression in lymphoid cell lines and lack of expression in myeloid cell lines.

Interferon therapy for agnogenic myeloid metaplasia complicated by immune hemolytic anemia.

A 69-year-old man with agnogenic myeloid metaplasia was treated with interferon-alpha 2 as part of a Phase II clinical trial. The patient responded to this treatment with a definite improvement in bone marrow histology, demonstrating increased numbers of hematopoietic colonies and partial resorption of the myelofibrosis. Chromosomal analysis on 20 cells suggested the re-emergence of normal hematopoietic progenitor cells: whereas previously, all metaphase spreads demonstrated a deletion in chromosome 20, the patient was now chimeric, with two of 20 cells exhibiting a normal karyotype. Nevertheless, the patient's anemia progressed during interferon therapy, with the development of an immunologically mediated hemolytic disorder. This hemolytic process developed after prolonged treatment with interferon, accelerated during therapy, and resolved following splenectomy and withdrawal of the drug. Initially, screening tests failed to detect the presence of the autoantibody. Similar immunologic processes may have been overlooked in other patients treated with interferon, especially if tests for autoantibodies were obtained early in their course of treatment. This case suggests a therapeutic role for interferon-alpha 2 in the management of the myeloproliferative diseases. It is presented, too, to underscore the immunomodulatory potential of the biologic response modifiers and their capacity to induce immunologic disorders.

Constitutive expression of the c-fos protooncogene in murine keratinocytes: potentiation of the mitogenic response to insulin-like growth factor 1.

In order to determine the biological effects of activation of the c-fos protooncogene on growth and differentiation of BALB/MK mouse keratinocytes, these cells were transfected with the plasmid pMAN-fos, which encompasses the human c-fos coding region under transcriptional control of a mouse mammary tumor virus promoter, as well as the gene encoding neomycin phosphotransferase. Of approximately 70 individual clones obtained by selection in Geneticin, 5 clones that constitutively expressed c-fos mRNA as well as p55fos protein were selected for phenotypic analysis. Each of these clones displayed density-dependent growth arrest at confluency when deprived of serum and mitogens. DNA synthesis could be reinitiated in quiescent cultures by treatment with epidermal growth factor to a similar extent as in the parental line. In four of five fos transfectants, insulin-like growth factor 1 potentiated the mitogenic response to epidermal growth factor more than 10-fold, compared to only 2.5-fold in the parental cells. The enhanced response to insulin-like growth 1 could not be attributed to changes in the number or the affinity of receptors for the growth factor. Finally, the constitutive expression of c-fos did not interfere with the induction of terminal differentiation by calcium.

Primary pulmonary Hodgkin's disease.

Primary pulmonary Hodgkin's disease is a rare but distinct entity, to be distinguished from nodal Hodgkin's disease and from lymphomas involving the lung secondarily. Sixty-one cases have now been reported in the world's literature. This lymphoma affects women more frequently than men, and typically involves the superior portions of the lungs. Radiologically, it appears as a solitary mass or multinodular disease; inhomogeneity or cavitation of these lesions are common. Since the presentation of this disease is nonspecific, and as noninvasive tests are rarely revealing, diagnosis requires an open thoracotomy and lung biopsy. Factors which correlate with a poorer prognosis include "B" symptoms, bilateral disease, multilobe involvement, penetration of the pleura, and cavitation. The staging and treatment of these lymphomas according to the extent of pulmonary involvement are recommended, as radiotherapy or combination chemotherapy may be effective in appropriately selected patients.