Progress in Histochemistry and Cytochemistry最新文献

Islets form in the pancreas after the first endocrine cells have arisen as either single cells or small cell clusters in the epithelial cords. These cords constitute the developing pancreas in one of its earliest recognizable stages. Islet formation begins at the time the cords transform into a branching ductal system, continues while the ductal system expands, and finally stops before the exocrine tissue of ducts and acini reaches its final expansion. Thus, islets continuously arise from founder cells located in the branching and ramifying ducts. Islets arising from proximal duct cells locate between the exocrine lobules, develop strong autonomic and sensory innervations, and pass their blood to efferent veins (insulo-venous efferent system). Islets arising from cells of more distal ducts locate within the exocrine lobules, respond to nerve impulses ending at neighbouring blood vessels, and pass their blood to the surrounding acini (insulo-acinar portal system). Consequently, the section of the ductal system from which an islet arises determines to a large extent its future neighbouring tissue, architecture, properties, and functions. We note that islets interlobular in position are frequently found in rodents (rats and mice), whereas intralobularly-located, peripheral duct islets prevail in humans and cattle. Also, we expound on bovine foetal Laguesse islets as a prominent foetal type of type 1 interlobular neuro-insular complexes, similar to neuro-insular associations frequently found in rodents. Finally, we consider the probable physiological and pathophysiological implications of the different islet positions within and between species.

Estradiol synthesis in the ovaries is regulated via feedback mechanisms mediated by gonadotrophin-releasing hormone (GnRH) and gonadotrophins, secreted by the hypothalamus and the pituitary, respectively. Estradiol synthesis also takes place in the hippocampus. In hippocampal slice cultures of female animals, GnRH regulates estradiol synthesis dose-dependently. Hence, both hippocampal and ovarian estradiol synthesis are synchronized by GnRH. Hippocampus-derived estradiol is essential to synapse stability and maintenance because it stabilizes the spine cytoskeleton of hippocampal neurons. Inhibition of hippocampal estradiol synthesis in mice, however, results in loss of spines and spine synapses in females, but not in males. Stereotaxic application of GnRH to the hippocampus of female rats confirms the regulatory role of GnRH on estradiol synthesis and synapse density in the female hippocampus in vivo. This regulatory role of GnRH necessarily results in estrus cyclicity of spine density in the hippocampus of females.

Besides its classical role in bone and calcium homeostasis, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), the active form of vitamin D, has many non-classical effects; antiproliferative, anti-apoptotic and prodifferentiating effects of 1,25(OH)₂D₃ have been described in several tumour types in preclinical models. This review focuses on the insights gained in the elucidation of the role of 1,25(OH)₂D₃ in the normal thyroid and in the pathogenesis, progression and treatment of thyroid cancer, the most common endocrine malignancy. An increasing amount of observations points towards a role for impaired 1,25(OH)₂D₃-VDR signalling in the occurrence and progression of thyroid cancer, and a potential for structural analogues in the multimodal treatment of dedifferentiated iodine-resistant thyroid cancer. A role for vitamin D in thyroid-related autoimmunity is less convincing and needs further study. Altered 1,25(OH)₂D₃-VDR signalling does not influence normal thyroid development nor thyrocyte function, but does affect C-cell function, at least in rodents. If these findings also apply to humans deserves further study.

For a very long time, we studied the metallophilic macrophages of the rodent thymus and in this review our results on morphological, histochemical, enzymehistochemical, immunohistochemical, ultrastructural and functional features of these cells, as well as the molecular regulation of their development, will be presented. Furthermore, the differences between species will also be discussed and the comparisons with similar/related cell types (metallophilic macrophages in the marginal sinus of the spleen, subcapsular sinus of the lymph nodes and germinal centers of secondary lymphoid follicles) will be made. Metallophilic macrophages are strategically positioned in the thymic cortico-medullary zone and are very likely to be involved in: (i) the metabolism, synthesis and production of bioactive lipids, most likely arachidonic acid metabolites, based on their histochemical and enzymehistochemical features, and (ii) the process of negative selection that occurs in the thymus, based on their ultrastructural features and their reactivity after the application of toxic or immunosuppressive/immunomodulatory agents. Taken together, their phenotypic and functional features strongly suggest that metallophilic macrophages play a significant role in the thymic physiology.

Microscopy-based imaging is booming and the need for tools to retrieve quantitative data from images is urgent. This book provides simple but reliable tools to generate valid quantitative gene expression data, at the mRNA, protein and activity level, from microscopic images in relation to structures in cells, tissues and organs in 2D and 3D. Volumes, areas, lengths and numbers of cells and tissues can be calculated and related to these gene expression data while preserving the 2D and 3D morphology. Image cytometry thus provides a comprehensive toolkit to study molecular processes and structural changes at the level of cells and tissues.

The diagnosis of neoplastic disease still lays its foundations on the detection of altered tissue morphology. Most importantly, cancer begins, at least in many cases as a disease with altered tissue pattern formation. It is therefore rather surprising that the issue regarding the possible mechanistic role of such property in the pathogenesis of cancer has received relatively little attention so far. To be more specific, we need to ask the following question: is altered tissue pattern formation a mere bystander, with its pervasive presence along the entire carcinogenic sequence, or does it play a role in fuelling this process? Pathways related to morphogenesis and to the establishment of cell polarity will be considered for their possible mechanistic involvement in early phases of neoplastic disease. Evidences and hypotheses relating altered tissue pattern formation to the emergence of the tumor microenvironment and to neoplastic progression will be discussed.

Since its introduction during the last decade, MALDI mass spectrometry imaging (MSI) is now a routine technique in biology. Nevertheless, a missing link exists in MALDI MSI. Lipids, peptides/proteins, metabolites and drugs can easily be mapped using MALDI-MSI, but this technique has not yet been used to map the transcriptome, which includes microRNA, siRNA and other components. This latter field of research is now one of the major fields in clinical research and needs to be explored using MALDI-MSI. To investigate the transcriptome, a novel imaging technique has been developed called Tag-Mass imaging mass spectrometry. The aim of this review is to discuss this technique from its history to its place in the future of mass spectrometric imaging.

Every amyloid disease needs to be assessed for chemical composition of its amyloid because amyloid is pathogenetically diverse and each of the chemical amyloid types requires a different therapy. Basically four different approaches are being applied for typing of amyloid using immunohistochemistry, immunochemistry, mass spectrometry and chemistry. It is shown here how an easy immunohistochemical procedure has been developed over the years that can be used to classify specifically amyloid proteins for clinico-pathologic routine use. A larger number of tissues with chemically or immunochemically typed amyloids served as prototypes for developing a set of validated amyloid antibodies. These were examined for their performance to classify a larger number of tissues of patients submitted to us and other institutions allowing independent evaluation. The data reveal that out of 663 patients, including 15 different amyloid types, all 119 prototype Amyloids (100%) have been classified correctly and 97.9% of consecutive 581 unknown amyloid tissues submitted for typing to our laboratory of whom 37 became later prototypes. Twelve samples (2.1%) could not be classified. By using appropriate amyloid antibodies in a comparative manner, this procedure is accurate. It identifies the respective amyloid type and excludes simultaneously other amyloids. Its improved performance leads to an accurate amyloid diagnosis in most cases and provides a diagnostic marker which is independend of any other information for therapeutic considerations. These results can be obtained within a day in institutes competent in performing immunohistochemistry. This is the first report on immunhistochemical typing of amyloid providing detailed illustrations of the original results for training purposes. When the immunohistochemical method presented here was compared with mass spectrometry, a more recent method for amyloid typing, the advantages and failures of both methods became apparent in an international blinded comparison.