Abnormal neuronal and glial argyrophilic fibrillary structures in the brain of an aged albino cynomolgus monkey (Macaca fascicularis)

An aged albino male cynomolgus monkey (Macaca fascicularis) more than 35 years old died after showing neurological signs including gait disturbance, trembling, drowsing tendency and a decrease in activity. Neuropathological examination revealed glial fibrillary tangles (GFTs) mainly distributed in the putamen, caudate nucleus, thalamic nuclei, substantia nigra, red nucleus, globus pallidus, trapezoid body, pyramid, pons and medulla oblongata of the brain, and neurofibrillary tangles (NFTs) in the thalamic nuclei. These structures were positively stained by the modified Gallyas-Braak (GB) method and immunostained for tau. The tau-positive argyrophilic GFTs were morphologically classified into four types, as in human cases, i.e., tufts of abnormal fibers (TAFs), thorn-shaped astrocytes (TSAs), glial coiled bodies (GCBs) and argyrophilic threads (ATs) depending on their GB profiles, and GCBs were the major structures in this case. Some of these structures were also immunoreactive for α-synuclein. The glial cells possessing the structures were negative for glial fibrillary acidic protein, a marker for astrocytes, indicating that the argyrophilic GFTs were present in oligodendroglia. In addition, marked neuronal loss and ubiquitin-positive spheroid bodies were observed in the substantia nigra and globus pallidus. According to the characteristic distribution of the argyrophilic structures in neurons and glial cells as well as clinical signs, the monkey might have suffered from a neurodegenerative disease such as progressive supranuclear palsy (PSP). This is the first report of the occurrence of a neurodegenerative disease in a nonhuman animal. Received: 16 November 1999 / Revised, accepted: 31 January 2000     

Lectin histochemistry in the aged dog brain

Formalin-fixed and paraffin-embedded canine brains were examined histochemically using 15 selected lectins. Concanavalin A (Con A), Lens culinaris agglutinin, Lycopersicon esculentum agglutinin (LEL) and Limulus polyphemus agglutinin (LPA) labeled neurons in an age-dependent manner. These and some other lectins [Dolichos biflorus agglutinin (DBA), Vicia villosa agglutinin (VVA), Ricinus communis agglutinin 120 (RCA-I), Bandeiraea simplicifolia agglutinin (BSL-I), and Phaseolus vulagaris agglutinin-L (PHA-L)] also age-dependently labeled glial cells. These results indicate that monosaccharide composition and biochemical metabolism in brain cells change with age and that these lectins may be useful as histochemical markers for investigating senile changes in the canine brain. However, no significant correlation was found between ApopTag-positive and lectin-positive cells. Amyloid plaques were positive for Con A, DBA, Glycine maximus agglutinin (SBA), LEL, PHA-L, Limax flavus agglutinin (LFA) and VVA. Among these lectins, VVA, SBA and LFA intensely stained amyloid both in blood vessel walls and senile plaque cores. Therefore, the sugar residues recognized by these lectins likely play specific roles in β-amyloid deposition in the aged dog brain. Received: 2 June 1997 / Revised: 21 July 1997, 28 August 1997 / Accepted: 3 October 1997     

Deposition of amyloid β protein (Aβ) subtypes [Aβ40 and Aβ42(43)] in canine senile plaques and cerebral amyoloid angiopathy

To clarify the immunohistochemical features of canine senile plaques (SPs) and cerebral amyloid angiopathy (CAA), the distribution of the amyloid β protein (Aβ) subtypes Aβ40 and Aβ42(43), Aβ precursor protein (APP), and glial cell reaction were examined in the brains of seven aged dogs (12–18 years). Aβ42(43) was found to be deposited in all types of SPs, whereas Aβ40 was deposited only in mature (classical and primitive) plaques. CAA, which was located along parenchymal and meningeal arterioles and capillaries, consisted of both subtypes of Aβ. APP was exhibited in normal and degenerative neurons and swollen neurites of mature plaques. It was, therefore, considered that Aβ42(43) in diffuse plaques might be derived from APP in neurons, while Aβ40 and Aβ42(43) in mature plaques might be generated from APP in swollen neurites in the plaque. In contrast to the case in humans, in whom deposition of Aβ40 and Aβ42(43) in the mature plaques is predominantly associated with microglial reaction, in dogs we found that it was closely associated with astroglial reaction. The present findings showed characteristics of canine SPs which are different from those of humans. Received: 11 October 1996 / Revised: 27 March 1997, 10 April 1997 / Accepted: 10 April 1997     

First Evidence of Carp Edema Virus Infection of Koi Cyprinus carpio in Chiang Mai Province,Thailand

The presence of carp edema virus (CEV) was confirmed in imported ornamental koi in Chiang Mai province, Thailand. The koi showed lethargy, loss of swimming activity, were lying at the bottom of the pond, and gasping at the water’s surface. Some clinical signs such as skin hemorrhages and ulcers, swelling of the primary gill lamella, and necrosis of gill tissue, presented. Clinical examination showed co-infection by opportunistic pathogens including Dactylogyrus sp., Gyrodactylus sp. and Saprolegnia sp. on the skin and gills. Histopathologically, the gill of infected fish showed severe necrosis of epithelial cells and infiltrating of eosinophilic granular cells. Electron microscope examination detected few numbers of virions were present in the cytoplasm of gill tissue which showed an electron dense core with surface membranes worn by surface globular units. Molecular detection of CEV DNA from gill samples of fish was performed by polymerase chain reaction (PCR) and confirmed by nested-PCR. Phylogenetic analyses revealed that CEV isolate had 99.8% homology with the CEV isolated from South Korea ({"type":"entrez-nucleotide","attrs":{"text":"KY946715","term_id":"1311086786","term_text":"KY946715"}}KY946715) and Germany ({"type":"entrez-nucleotide","attrs":{"text":"KY550420","term_id":"1272735997","term_text":"KY550420"}}KY550420), and was assigned to genogroup IIa. In conclusion, this report confirmed the presence of CEV infection of koi Cyprinus carpio in Chiang Mai province, Thailand using pathological and molecular approaches.