Neuropathologic Findings of Bromethalin Toxicosis in the Cat

Ten random source male domestic shorthair cats, 2 to 6 years old and 3.0–4.4 kg body weight, were each given a single oral dose (1.5 mg/kg) of bromethalin (cat Nos. 1–5) or bait vehicle carrier (cat Nos. 6–10). Bromethalin-dosed cats developed a toxic syndrome characterized by ataxia, focal motor seizures, vocalization, decerebrate posture, decreased conscious proprioception, recumbency, depression, and semicoma. Bromethalin-dosed cats were euthanatized if seizure activity or hindlimb paralysis developed. Survival times were 48 hours (cat No. 1), 89 hours (cat No. 2), 90 hours (cat No. 3), and 97 hours (cat No. 4). Control cats (cat Nos. 6–10) and one bromethalin-dosed cat (cat No. 5) were euthanatized on day 20 after dosing. Spongy change (edema—characterized by the formation of vacuoles in extracellular spaces and myelin lamellae), hypertrophied fibrous astrocytes, and hypertrophied oligodendrocytes were observed in the white matter of the cerebrum, cerebellum, brain stem, spinal cord, and optic nerve of all bromethalin-dosed cats. Spongy change occasionally extended into contiguous cerebellar Purkinje cell layer and cerebral cortical gray matter. The severity of lesions varied among cats but was most pronounced in cat No. 5 (480 hours after dosing). A leukocytic inflammatory response, gitter cell (macrophage) response, or axonal degeneration was not observed in the vacuolated areas. Ultrastructural findings included separation of myelin lamellae at the interperiod lines with the formation of intramyelinic vacuoles (intramyelinic edema), rupture and coalescence of intramyelinic vacuoles into larger extracellular spaces (spongy change), and pronounced cytosolic edema of astrocytes and oligoden-droglial cells.

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Patterns of retrograde axonal degeneration in the visual system

Brain ◽

10.1093/brain/awz221 ◽

2019 ◽

Vol 142 (9) ◽

pp. 2775-2786 ◽

Cited By ~ 1

Author(s):

Willemien A de Vries-Knoppert ◽

Johannes C Baaijen ◽

Axel Petzold

Keyword(s):

Experimental Data ◽

Optical Coherence Tomography ◽

Ganglion Cell ◽

Axonal Degeneration ◽

Ganglion Cell Layer ◽

Cell Layer ◽

Region Of Interest ◽

Plexiform Layer ◽

Inner Plexiform Layer ◽

Layer Region

Abstract Conclusive evidence for existence of acquired retrograde axonal degeneration that is truly trans-synaptic (RTD) has not yet been provided for the human visual system. Convincing data rely on experimental data of lesions to the posterior visual pathways. This study aimed to overcome the limitations of previous human studies, namely pathology to the anterior visual pathways and neurodegenerative co-morbidity. In this prospective, longitudinal cohort retinal optical coherence tomography scans were acquired before and after elective partial temporal lobe resection in 25 patients for intractable epilepsy. Newly developed region of interest-specific, retinotopic areas substantially improved on conventional reported early treatment diabetic retinopathy study (ETDRS) grid-based optical coherence tomography data. Significant inner retinal layer atrophy separated patients with normal visual fields from those who developed a visual field defect. Acquired RTD affected the retinal nerve fibre layer, ganglion cell and inner plexiform layer and stopped at the level of the inner nuclear layer. There were significant correlations between the resected brain tissue volume and the ganglion cell layer region of interest (R = −0.78, P < 0.0001) and ganglion cell inner plexiform layer region of interest (R = −0.65, P = 0.0007). In one patient, damage to the anterior visual pathway resulted in occurrence of microcystic macular oedema as recognized from experimental data. In the remaining 24 patients with true RTD, atrophy rates in the first 3 months were strongly correlated with time from surgery for the ganglion cell layer region of interest (R = −0.74, P < 0.0001) and the ganglion cell inner plexiform layer region of interest (R = −0.51, P < 0.0001). The different time course of atrophy rates observed relate to brain tissue volume resection and suggest that three distinct patterns of retrograde axonal degeneration exist: (i) direct retrograde axonal degeneration; (ii) rapid and self-terminating RTD; and (iii) prolonged RTD representing a ‘penumbra’, which slowly succumbs to molecularly governed spatial cellular stoichiometric relationships. We speculate that the latter could be a promising target for neuroprotection.

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SEM of Hepatocytes and Biliary Passages in Goldfish Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080213 ◽

1977 ◽

Vol 35 ◽

pp. 556-557

Author(s):

Waykin Nopanitaya ◽

Joe W. Grisham ◽

Johnny L. Carson

Keyword(s):

Carassius Auratus ◽

Cell Layer ◽

Three Dimensional ◽

Cell Types ◽

Biliary System ◽

Fish Food ◽

Commercial Fish ◽

Goldfish Carassius Auratus ◽

Commercial Fish Food

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.

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Anchoring Fibrils in Arterial Endothelium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063287 ◽

1969 ◽

Vol 27 ◽

pp. 274-275

Author(s):

A. Trillo

Keyword(s):

Carotid Arteries ◽

Animal Species ◽

Cell Layer ◽

Present Communication ◽

Internal Elastic Lamina ◽

Endothelial Cell Layer ◽

Structural Details ◽

Rats And Mice ◽

Arterial Endothelium ◽

Elastic Lamina

There are conflicting reports regarding some fine structural details of arteries from several animal species. Buck denied the existence of a sub-endothelial space, while Karrer and Keech described a space of variable width which separates the endothelium from the underlying internal elastic lamina in aortas of aging rats and mice respectively.The present communication deals with the ultrastrueture of the interface between the endothelial cell layer and the internal elastic lamina as observed in carotid arteries from rabbits of varying ages.

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Bronchial stereocilia in the immotile cilia syndrome: A case report

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110635 ◽

1984 ◽

Vol 42 ◽

pp. 52-53

Author(s):

George Price ◽

Lizardo Cerezo

Keyword(s):

Surface Modifications ◽

Respiratory Epithelium ◽

Immotile Cilia ◽

Kartagener's Syndrome ◽

Membrane Blebs ◽

Radial Spokes ◽

Males And Females ◽

Dynein Arms ◽

Ultrastructural Finding ◽

Ultrastructural Findings

Ultrastructural defects of ciliary structure have been known to cause recurrent sino-respiratory infection concurrent with Kartagener's syndrome. (1,2,3) These defects are also known to cause infertility in both males and females. (4) Overall, the defects are defined as the Immotile, or Dyskinetic Cilia Syndrome (DCS). Several ultrastructural findings have been described, including decreased number of cilia, multidirection orientation, fused and compound cilia, membrane blebs, excess matrix in the axoneme, missing outer tubular doublets, translocated doublets, defective radial spokes and dynein arms. A rare but noteworthy ultrastructural finding in DCS is the predominance of microvilli-like structures on the luminal surface of the respiratory epithelium. (5,6) These permanent surface modifications of the apical respiratory epithelium no longer resemble cilia but reflect the ultrastructure of stereocilia, similar to that found in the epidydimal epithelium. Like microvilli, stereocilia are devoid of microtubular ultrastructure in comparison with true cilia.

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Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159692 ◽

1990 ◽

Vol 48 (3) ◽

pp. 430-431

Author(s):

Maria Anna Pabst

Keyword(s):

Apis Mellifera ◽

Distal Part ◽

Cell Layer ◽

Single Layer ◽

Photoreceptor Cells ◽

Distal Segment ◽

Compound Eyes ◽

Thin Sections ◽

Ultrastructural Studies ◽

Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

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New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160467 ◽

1990 ◽

Vol 48 (3) ◽

pp. 582-583

Author(s):

S. F. Hayes ◽

M. D. Corwin ◽

T. G. Schwan ◽

D. W. Dorward ◽

W. Burgdorfer

Keyword(s):

Lyme Disease ◽

Borrelia Burgdorferi ◽

Structural Characterization ◽

Negative Staining ◽

Low Speed ◽

Thin Sectioning ◽

Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

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