1,720,968 research outputs found
Infestazione non letale da larve di gnatidi (Crustacea, Isopoda, Gnathiidae) in un acquario marino ornamentale mediterraneo
No full textPatologie nell’allevamento in condizioni controllate del goodeide messicano estinto in natura Zoogoneticus tequila (Webb & Miller, 1998)
No full textHistopathological findings in the central nervous system of Montezuma swordtail (Xiphophorus montezumae Jordan & Snyder, 1899) fry with early mortality associated with severe neurological signs
No full textIntroduction: Neurological syndromes in fry may be associated with internal or external hydrocephalus
caused by a variety of injuries, including toxic, nutritional, infectious, and genetic/heritable
factors. However, limited information concerning histopathological features of nervous tissue of fish
with neurological signs is available.
Materials and Methods: A total of 33 live, swim-up fry were produced in an aquarium colony of
the live-bearer Xiphophorus montezumae, composed by 3 females and 1 male. About fifteen days
after birth, fry showed severe neurological signs ranging from anorexia and lethargy to swimming
difficulties, whirling and loss of equilibrium. No gross abnormality was evident. Immediately after
spontaneous death, 31 fry were formalin-fixed and routinely processed for histology. Two fry survived
without clinical signs. Adult fish were not affected.
Results: Histological examination of all affected fry revealed various degrees of external hydrocephalus
characterized by increased space between the meninges and the brain, with presence
of scant protein-like material in the sub-arachnoid space. Variable, usually mild, vacuolation of the
nervous tissue was also observed. Brain was only covered by the skin on the dorsal part of chondrocranium.
Conclusions: This is the first description of neurological disease associated with histological features
of external hydrocephalus in the Montezuma swordtail. Water quality analysis and absence
of pharmacological treatments allowed to exclude toxic causes. Vitamin deficiencies were also unlikely,
since a well-balanced and integrated, commercial diet specific for swim-up fry was provided.
Based upon the lack of evidence for an infectious, especially viral, etiology, a congenital, possibly
genetic, condition may be supposed
Spinal deformities in a wild line of Poecilia wingei bred in captivity: report of cases and review of the literature
No full textPathology Survey on a Captive-Bred Colony of the Mexican Goodeid, Nearly Extinct in the Wild, Zoogoneticus tequila (Webb & Miller 1998)
Full text linkThe Mexican Goodeid, Zoogoneticus tequila, is considered nearly extinct in the wild and it is maintained in captivity by the nonprofit international “Goodeid Working Group.” The unique Italian colony has produced about 180 fish so far. The observable diseases were registered and some fish were submitted, immediately after spontaneous death, to necroscopic and histopathologic exams. Encountered diseases included the following: 7 cases of scoliosis (2 males and 5 females); 2 fish with a similar congenital deviation of ocular axis; 1 adult male with left corneal opacity, presumably of traumatic origin; 1 female fish with a large subocular fluid-filled sac, histologically referable to a lymphatic cyst, similarly to the eye sacs of a Goldfish variety (Carassius auratus) called bubble eye; and 1 female fish with recurrent abdominal distension consequent to distal bowel dilation and thinning, associated with complete mucosal atrophy, and comparable to intestinal pseudo-obstruction syndromes described in humans and various animal species. The absence of infectious or parasitic diseases, as well as the low incidence of diseases potentially related to environmental alterations or nutritional disorders such as spinal deformities, suggests the adequacy of breeding management techniques of Z. tequila for its conservation and reintroduction in to the original habitat in the near future
Histological observations on conjoined twins occurring among a captive-bred wild line of Poecilia wingei (Poeser, Kempkes & Isbrücker)
No full textMultiple, life-compatible, congenital physical deformities in association with splenic lymphangiomatosis in Zoogoneticus tequila (Webb & Miller, 1998)
No full textThe present case describes an adult female Zoogoneticus tequila showing a congenital, marked
shortening with left deviation of the upper and lower jaws, in association with microphthalmia
of the left eye. The fish was normally fed and had a normal reproductive behaviour. After
spontaneous death occurred at an advanced age, the fish was submitted for necropsy
examination, which revealed the presence of an oval, 1 cm × 0.5 cm × 0.5 cm in size, cystic
structure containing clear amber fluid, located in the coelomic cavity, in place of the spleen.
Histopathological examination revealed multiple cystic spaces empty or filled with a slightly
eosinophilic, homogenous, proteinaceous material, and lined by flattened, vimentin-positive
endothelial-like cells. Residual parts of splenic tissue were also admixed with cystic spaces,
suggesting a final diagnosis of cystic lymphangiomatosis of the spleen, which has not been
previously described in fish. This is the first report of multiple, life-compatible, congenital
physical deformities in association with splenic lymphangiomatosis in Zoogoneticus tequila
Ovarian teratoma in an adult female Zoogoneticus tequila (Webb & Miller 1998): histological and immunohistochemical features.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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