Pheochromocytomas can have a highly variable presentation, making diagnosis challenging. To think of the tumor represents the crucial initial step, but establishing the diagnosis requires biochemical ...evidence of excessive catecholamine production and imaging studies to localize the source. Currently, however, there exist no generally agreed upon guidelines based on which tests and testing algorithms should be used to confirm and locate or exclude a suspected pheochromocytoma. Choice of biochemical tests and imaging studies instead usually depends on institutional experience. At the First International Symposium on Pheochromocytoma (ISP2005), held in Bethesda in October 2005, a panel of experts and patient representatives discussed current problems and available options for tumor diagnosis and localization and formulated recommendations, which were subsequently agreed upon by those in attendance at the meeting. This article summarizes the discussion and recommendations derived from that session.
The management of small papillary thyroid cancers, particularly microcarcinomas with low-volume nodal disease confined to the central neck, presents special challenges. Although the overall risk of ...thyroid cancer-related death and distant metastatic recurrence in such patients is low, the risk of local-regional recurrence is quite variable (ranging from 3 to 22 %). In risk stratifying such cases, it is important to consider the aggressiveness of behavior of the nodal metastases (including the number and size of involved nodes and the presence of extranodal extension) and the presence of other adverse prognostic disease features. Ultrasound imaging of the neck is critical in the preoperative evaluation and disease follow-up. The best available observational data are conflicting as to whether radioactive iodine (RAI) adjuvant treatment reduces the risk of thyroid cancer recurrence in this patient group. Randomized controlled trials are needed to clarify the role of RAI adjuvant treatment in this population.
The composition of guard cell walls in sugar beet leaves (Beta vulgaris L.) was studied by using histochemical staining and immunocytochemical detection of cell wall antigens. The findings were ...compared with those in the walls of epidermal and mesophyll cells. Probing of leaf sections with monoclonal antibodies against pectins, terminal fucosyl residues linked α‐(1→2) to galactose, β‐(1→3)‐glucans and arabinogalactan‐proteins revealed several specific features of guard cells. Pectic epitopes recognized by JIM7 were homogeneously distributed in the wall, whereas pectins recognized by JIM5 were not found in the walls themselves, but were abundant in the cuticular layer. Large amounts of molecules bearing terminal fucose were located predominantly in ventral and lateral guard cell walls. Much smaller amounts were detected in dorsal walls of these cells, as well as in the walls of pavement and mesophyll cells. Conspicuous accumulation of these compounds was observed in the vicinity of the guard cell plasmalemma, whereas labelling was scarce in the areas of the wall adjacent to the cell surface. The presence of callose clearly marked the ventral wall between the recently formed, very young guard cells. Callose also appeared in some mature walls, where it was seen as punctate deposits that probably reflected a specific physiological state of the guard cells. Large amounts of arabinogalactan‐proteins were deposited within the cuticle, and smaller amounts of these proteoglycans were also detected in other tissues of the leaf. The histochemical and immunocytochemical structure of the guard cell wall is discussed in the light of its multiple functions, most of which involve changes in cell size and shape.
Thiocyanatonickel(II) and thiocyanatocobalt(II) complexes of the composition Ni(NCS)2(HIm)2 (1) and Co(NCS)2(HIm)2 (2), where HIm = imidazole, were prepared and studied. In particular, the crystal ...structure of Ni(NCS)2(HIm)2 was determined by X-ray methods. This compound crystallizes in the monoclinic system, space group P21/n, with a = 7.720(1) Å, b = 5.557(1) Å, c = 13.774(3) Å, β = 102.54(3)°, and Z = 2. Its structure consists of a one-dimensional polymeric chain in which nickel(II) ions are bridged by two thiocyanate groups bonding in an end-to-end fashion in a trans arrangement. The Ni···Ni distance is 5.557(1) Å. The crystal packing is determined by the intermolecular hydrogen bonds and ring-stacking interactions. From their X-ray powder-diffraction patterns and IR spectra, the complexes 1 and 2 were found to be mutually isomorphous. The coordination compounds were identified and characterized using elemental analysis, magnetic measurements, and infrared and ligand-field spectra. Both complexes are first examples of ferromagnetically coupled one-dimensional polymeric compounds with double end-to-end thiocyanate bridges. The magnetic properties of the title compounds were investigated over the 1.9−290 K temperature range. The compounds exhibit long-range magnetic ordering with T c equal to 5.0 and 5.5 K for 1 and 2, respectively. Their isothermal magnetization was also studied. The magnetostructural properties of the nickel(II) compound obtained are discussed and compared to those of other double end-to-end thiocyanate-bridged nickel(II) complexes.
: Pheochromocytomas can have a highly variable presentation, making diagnosis challenging. To think of the tumor represents the crucial initial step, but establishing the diagnosis requires ...biochemical evidence of excessive catecholamine production and imaging studies to localize the source. Currently, however, there exist no generally agreed upon guidelines based on which tests and testing algorithms should be used to confirm and locate or exclude a suspected pheochromocytoma. Choice of biochemical tests and imaging studies instead usually depends on institutional experience. At the First International Symposium on Pheochromocytoma (ISP2005), held in Bethesda in October 2005, a panel of experts and patient representatives discussed current problems and available options for tumor diagnosis and localization and formulated recommendations, which were subsequently agreed upon by those in attendance at the meeting. This article summarizes the discussion and recommendations derived from that session.
The use of radioactive iodine (131I) for remnant ablation, adjuvant treatment, and treatment of metastases from differentiated thyroid carcinoma may be associated with side effects in numerous organ ...systems. Although many articles address the side effects of 131I, the characterizations of these effects vary widely because of a host of different factors. This chapter attempts to consolidate the literature by presenting, where appropriate, (1) the spectrum of signs and symptoms, as well as the frequency and severity of side effects; (2) a review of selected articles; (3) a discussion of preventive measures to reduce the frequency and severity of side effects; and (4) a discussion of the medical management when selected side effects do occur.
We related changes in the ultrastructural organization of the nucleoli with the results of quantitative in situ hybridizations to characterize rRNA metabolism during the development of microspore ...mother cells in the sugar beet anther (Beta vulgaris L.). In the course of meiotic prophase and early postmeiotic interphase the morphological characteristics of the nucleoli are typical of low or no transcriptional activity and a low rate of rRNA processing. However, we found evidence of an apparent increase in the relative numbers of 18 S rRNA transcripts in some stages of microsporogenesis. This was found in both the nucleoli and cytoplasm of pachytene meiocytes, and in later stages there was a spectacular accumulation of rRNA transcripts in nucleoli of the tetrad cells. Quantitative data are analyzed in the light of morphometric findings in the cell and their compartments to elucidate the degree to which changes in cell size are related to changes in labeling density and distribution. The results are discussed in terms of rRNA synthesis, transport and degradation as processes involved in the regulation of rRNA within microsporocytes and microspores.
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