China
Africa
Explore chapters and articles related to this topic
Neuropathology of Drugs of Dependence
Published in S.J. Mulé, Henry Brill, Chemical and Biological Aspects of Drug Dependence, 2019
L. Roizin, M. Halpern, M. M. Baden, M. Kaufman, S. Hashimoto, J. C. Liu, B. Eisenberg
Histochemical and electron microscopic investigations reveal that the drugs are bound in the tissues in a diversified distribution and concentration and that adverse and toxic drug reactions are associated with changes of the (a) hydrolytic enzyme systems, (b) fine ultrastructural alterations of the ultracellular organelles, (c) communication or transport mechanisms in the CNS (particularly the synaptic complex and axonal flow), and (d) membrane permeability (including brain-blood barrier).
Angiogenesis
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Conventional histology is widely used to quantitatively analyze angiogenesis. To visualize the vessels, different approaches can be used to prepare the tissue. There are basically two methods. There are injection techniques where the vessels are filled with a substance (e.g., India ink, plastic resins, radio-opaque suspensions for radioautography, fluorescent marker). Altematively, blood cells can be stained and the vessel lumen marked. The pitfall of such techniques is that there is a risk of not filling all the capillaries. This is particularly problematic considering the abundancy of capillary sprouts that are often missed when using these casting methods. Histochemical staining of the basement membrane helps to reveal capillaries in histological sections. The problem here is that the basement membrane is not fully developed and thereby not all vessels stain. Also, the staining of glycosaminoglycans is not specific, and other tissue components (e.g., glycogen) are stained. Enzyme histochemistry is another possibility for detecting capillaries for investigations using alkaline phosphatase or peroxidase staining. Hematoxlin-eosin or Masson’s trichrome are also used by staining the red blood cells and using these as markers of the vessels. Electron microscopy is a technique that can be used to investigate ultrastructure of the newly forming vessels. Together with immunocytochemical methods, substances can be identified that are responsible for vessel growth.8,113–116
Immunological Repertoire of the Dermal Microvascular Unit
Published in Brian J. Nickoloff, Dermal Immune System, 2019
Richard D. Sontheimer, Michael D. Tharp
Very recent work presented by Walsh and co-workers37 has demonstrated that the DPDC can be identified in normal human skin with a monoclonal antibody, MS-1, that was raised against human spleen tissue.38 This antibody was found to react with a previously undescribed high-molecular-weight antigen expressed by sinusoidal endothelial cells in spleen and other organs.38 These workers have now demonstrated that MS-1 reacts with the same population of perivascular dendritic cells in normal newborn and adult human skin that expresses HLA-DR and factor XIIIa.38 This observation strongly suggests that the previously described dermal dendrocyte and DPDC very likely represent the same cell type that can be identified rather specifically by the MS-1 monoclonal antibody.38 In addition, ultrastructural studies presented by Walsh et al.37 further suggest that the MS-1 + dermal dendrocyte/DPDC is morphologically quite similar to the same cell type that has been described as the veil cell.35
Impacts of ingested MWCNT-Embedded nanocomposites in Japanese medaka (Oryzias latipes)
Published in Nanotoxicology, 2021
Melissa Chernick, Alan Kennedy, Treye Thomas, Keana C. K. Scott, Christine Ogilvie Hendren, Mark R. Wiesner, David E. Hinton
Examination of liver ultrastructure corroborated and further expanded upon our observations in vivo and in histology. In addition, certain ultrastructural alterations were unique to specific materials tested. The only ultrastructural change that we observed after PETG exposure was swollen mitochondria within hepatocytes. Alteration of hepatic mitochondria would potentially compromise the high energy demand required by the liver for a variety of functions including bile secretion, gluconeogenesis, and protein synthesis (Lemasters 2013). One hypothesis for the change in mitochondria is that this resulted from leached additives (e.g. plasticizers, stabilizers). For example, inhibition of cytochrome P450s, not pursued in the present study, have, in other studies, generated free radical intermediates that led to mitochondrial-mediated oxidative stress (Anbumani and Kakkar 2018) or altered the first step in steroidogenesis, which occurs in the mitochondrial membrane (Diamante and Schlenk 2018). Another hypothesis is that nanoplastics created during the abrasion process are translocated to mitochondria. Nanoplastics have been shown to directly affect mitochondria in studies with zebrafish (Danio rerio) (Trevisan et al. 2020). However, methodological and analytical challenges associated with the recovery and quantification of nanoplastics prevent the testing of this hypothesis using these materials at this time (da Costa et al. 2019).
Diagnostic and prognostic significance of extent of subepithelial electron dense deposits in membranous glomerulonephritis
Published in Ultrastructural Pathology, 2021
The following questions arise from the ultrastructural findings: Sparse subepithelial electron dense deposit patients had widespread podocyte foot process effacement in areas without deposits, raising the question of what is causing the podocyte damage in areas without subepithelial electron dense deposits.In half of the sparse subepithelial electron dense deposit cases, the subepithelial electron dense deposits had a patchy distribution, rather than being uniformly sparsely distributed. The reason for this is unknown but it may be related to variability of interactions between antibody, podocyte and GBM in different glomerular regions, which in turn may be due to the distribution of the foot processes of individual podocytes on the GBM.Prominent clearing or resorption of deposits (stage 4 of the Ehrenreich and Churg ultrastructural classification of MGN, which in some cases has been associated with remission or resolution of MGN) was not common overall, but it was more common in segmental MGN than in sparse subepithelial electron dense deposits (in which prominent clearing of deposits was not seen) or global MGN. This raises the possibility that, in a minority of cases, segmental MGN may represent a later stage of MGN which is undergoing remission or resolution.
Smoking effect on the ultrastructural properties of cultured lung myofibroblasts
Published in Ultrastructural Pathology, 2021
Siri Lehtonen, Ninni-Ingrid Nurmos, Henna M Karvonen, Elisa Lappi-Blanco, Terttu Harju, Magnus Sköld, Riitta Kaarteenaho
The ultrastructural properties were analyzed as described previously.12 Briefly, the amount of intracellular actin filaments, the amount of extracellular component of FNX and the amount of pericellular ECM were quantified as low (+), moderate (++) or strong (+++). The type of FNX was categorized according to Singer classification into tandem, plaque, or track-like,11 and the subtype of the track-like FNX as follows: straight/rigid, curved or fragmentary/scanty.13 The occurrence of adherens- and gap-type junctions and dilated rER was evaluated as the numbers of positive cases. Two investigators separately assessed the semi-quantitative TEM findings and there was almost perfect agreement in their evaluations (p < .001, Fisher; kappa coefficient = 0.947).