Histology and histopathology Vol.13, nº 1 (1998)
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- PublicationOpen AccessThe cytoskeleton in skeletal, cardiac and smooth muscle cells(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Stromer, M. H.The muscle cell cytoskeleton consists of proteins or structures whose primary function is to link, anchor or tether structural components inside the cell. Two important attributes of the cytoskeleton are strength of the various attachments and flexibility to accommodate the changes in cell geometry that occur during contraction. In striated muscle cells, extramyofibrillar and intramyofibrillar domains of the cytoskeleton have been identifi ed , Evidence of the extramyofibrillar cytoskeleton is seen at the cytoplasmic face of the sa rcolemma in striated muscle where vinculin- and dystrophin-rich costameres adjacent to sarcomeric Z lines anchor intermedi a te filaments that span from peripheral myofibrils to the sarcolemma. Intermediate filaments also link Z lines of adjacent myofibrils and may, in some muscles, link successive Z lines within a myofibril at the surface of the myofibril. The intramyofibrillar cytoskeletal domain includes elastic titin filaments from adjacent sarcomeres that are anchored in the Z line and continue through the M line at the center of the sa rcomere; inelastic nebulin filaments also anchored in the Z line and co-extensible with thin filaments; the Z line, which also anchors thin filaments from adjacent sarcomeres; and the M line, which forms bridges between the centers of adjacent thick filaments, In smooth muscle, the cytoskeleton includes adherens junctions at the cytoplasmic face of the sarcolemma, which a nchor B-actin filaments and intermediate filaments of the cytoskeleton, and dense bodies in the cytoplasm, which also anchor actin filaments and intermediate filaments and which may be the interface between cytoskeletal and contractile elements.
- PublicationOpen AccessHistochemical and ultrastructural study of skeletal muscle in patients with sepsis and multiple organ failure syndrome (MOFS)(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Díaz, N. L.; Finol, H. J.; Torres, S. H.; Zambrano, C. I.; Adjounian, H.Muscle biopsies for histochemical and ultrastuctural analysis were obtained from seven critically ill patients admitted to the Intensive Care Unit of the "Domingo Luciani" Hospital, Caracas, Venezuela. The sample included two patients with sepsis of abdominal origin, and five that presented sepsis/MOFS, with renal, hepatic, and respiratory disturbances and muscular weakness. Sections were examined for myosin adenosine triphosphatase (ATPase) after pre-incubation with both acid buffer (pH 4.37 and 4.6) and alkaline buffer (pH 10.3), for reduced nicotinamide dinucleotide diaphorase (NADHd), and for a-glycerophosphate dehydrogenase (a-GPDH). Sections were stained with hematoxilin and eosin to look for pathological changes and examined with a transmission electron microscope. Skeletal muscle of patients in early stage of sepsis showed a normal aspect with light microscopy, but at the ultrastructural level some of the fibres showed atrophy and some capillaries looked altered . Patients with sepsis/MOFS exhibited an evident muscle disorder with oedema. infiltrate, atrophy and segmental necrosis. All fibre types showed decrease in diameter; specially fibre types IIA and lIB . Intramuscular capillaries were thickened and occluded , indexes of capillarity were slightly reduced, and fibre oxidative activity was decreased. At ultrastructural level fibres showed severe atrophy, contractile system disorganization and segmental necrosis. Capillaries were also altered and the mononuclear cell infiltrate was abundant and represented by macrophages. lymphocytes and mastocytes.
- PublicationOpen AccessParacrine control of steroid hormone secretion by chromaffin cells in the adrenal gland of lower vertebrates(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Mazzocchi, G.; Gottardo, G.; Nussdorfer, G. G.The adrenal glands of lowe r vertebrates display a notable intermingling between steroidogenic and chromaffin tissues, which increases from Pisces to Al'es. As in mammals, adrenal chromaffin cells contain and release, in addition to catechol amines, serotonin and several peptides, which may affect the secretory acti vity of steroidogeni c cells in a paracrine manner. Stimulatory molec ul es in c lud e se roto nin , arg inin e-va so tocin. tachykinin s, vasoac ti ve intestinal peptide , pituita ry adenylate cyclase-acti vating peptide and calcitonin generelated peptide: inhibitory molec ul es are dopamine, somatotropic hormone-release inhibiting hormone and ga lanin . Epin ephrine and no repinephrine appe ar to stimulate steroid sec retion in Aves and to inhibit it in Pisces, while their ac tion in Amphibia is controversial. Likewise . atri a l natriureti c peptide exe rts an antisec re ta gog ue ac ti o n in Amphibia and a ma rk ed secretagogue effe ct in Pisces and Aves. The effects of opioids (enkephalins and endorphins) have scarcely been in vesti ga ted a nd th e findin gs obt a ined a re hi g hly qu esti o nabl e. Compared with the ama zin g ma ss of in vestigations carried out in mammals, studies in lower ve rtebrates a re few, and in large part pe rformed in Amphibia and Al'es. It appears that much further work has to be done by comparati ve endocrinologists to fully clari fy the physiolog ica l relevance of th e functi onal interactions between chromaffin and steroidogeni c cells in the adrenal glands of lower vertebrates.
- PublicationOpen AccessChemiluminescence: a sensitive detection system in in situ hybridization(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Musiani, M.; Pasini, P.; Zerbini, M.; Roda, A.; Gentilomi, G.; Gallinella, G.; Venturoli, S.; Manaresi, E.Chemiluminescence is the light emission produced by a chemical reaction in which chemically excited molecules decay to the ground state. The phenomenon is utilized in various analytical techniques in which small amounts of analytes or enzymes can be detected and quantified by measurement of the light emitted by bio- or chemiluminescent reactions. Recently chemiluminescence has been proposed as a valid alternative to radioactive or colorimetric methods in in situ hybridization assays, in which target nucleic acids are localized by labeled probes inside individual cells with the preservation of cell morphology. Chemi-luminescence in situ hybridization is performed using probes that are detected using enzymes with their appropriate chemiluminescent substrates. The luminescent signal from the hybrid formation is detected, analysed and measured with a high performance low light level imaging apparatus connected to an optical microscope and to a personal computer for quantitative image analysis. Generally, the instrumental system to detect positive signals after in situ hybridization operates in three steps: firstly tissue structures and cells are recorded in transmitted light then the luminescent signal is measured with an optimized photon accumulation; and then, after a computer elaboration of the luminescent signal with pseudocolors corresponding to the light intensity, an overlay of the two images on the screen provided by the transmitted light and by the luminescent signal allows the spatial distribution of the labeled probe to be localized and evaluated. The main advantages of chemiluminescence in situ hybridization are mainly the sensitivity, the quantifi-cation of the data, the objectivity of the evaluation and the digital imaging of the results. The chemiluminescence in situ hybridization assay, which can be applied to cell smears, archival frozen and paraffin embedded tissue samples, can be a useful tool for a sensitive and specific diagnosis of viral infections and for the detection and study of specific genic sequences inside the cells. The use of the chemi-luminescent in situ hybridization assay is also promising for an estimation and quantification of nucleic acids present in tissue samples or cellular smears and for imaging gene expression in cells.
- PublicationOpen AccessHyperlipidemia and kidney disease: Concepts derived from histopathology and cell biology of the glomerulus(F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 1998) Kamanna, V. S.; Roh, D. D.; Kirschenbaum, M. A.The association between hyperlipidemia and renal disease was noted by Virchow as earl y as the 19th ce ntury. Subseq ue ntl y, similar histopatho log ica l lipid depo siti o ns we re confirme d in diverse huma n a nd experimental renal diseases. Altho ugh, no studies have been established in man to suggest a causal re lationship between lipid s and the pathogenesis of rena l disease . compe llin g ev id e nce acc umul a te d in experimental animals suggests a direct role of lipids in the initiation and progression of glome rular disease. These studi es showed that cho lesterol-feed ing to various experimental animals induced the development of glomerul ar injury. Furthermore. the treatment of hype rlipidemic a nima ls with lipid lowering drugs prevented the deve lopment of glomenllosclerosis. In this article, we will rev iew recent advances made in understanding various aspects of lipid-mediated rena l injury inc ludin g bioc he mi ca l mec ha nisms of hype rlipidemia, a possible direct role of hyperlipidemi a in the pa th oge nesis o f ren a l disease, pathobiological acc umulation of lipids and lipoprote ins, biochemi cal and histological similarities between systemic atherosclerosis and glomerulosclerosis, and cellular processes invo lved in the development of glomerul ar disease. Furthermore, we will define cellular and mo lecul ar hypotheses that provide putative mechanisms by which hyperlipidemia a nd a theroge ni c lipo pro tei ns indu ce se ri es o f cy toregulatory peptide- med iated eve nts in vo lved in the development of glomerul ar disease.