B. Macrì

Erythropoietin and erythropoietin receptor expression after experimental spinal cord injury encourages therapy by exogenous erythropoietin.

OBJECTIVE:Erythropoietin (EPO) is a pleiotropic cytokine originally identified for its role in erythropoiesis. Recent studies have demonstrated that EPO and its receptor (EPO-R) are expressed in the central nervous system, where EPO exerts neuroprotective functions. Because the expression of the EPO and EPO-R network is poorly investigated in the central nervous system, the aim of the present study was to investigate whether the resident EPO and EPO-R network is activated in the injured nervous system. METHODS:A well-standardized model of compressive spinal cord injury in rats was used. EPO and EPO-R expression was determined by immunohistochemical analysis at 8 hours and at 2, 8, and 14 days in the spinal cord of injured and noninjured rats. RESULTS:In noninjured spinal cord, weak immunohistochemical expression of EPO and EPO-R was observed in neuronal and glial cells as well as in endothelial and ependymal cells. In injured rats, a marked increase of expression of EPO and EPO-R was observed in neurons, vascular endothelium, and glial cells at 8 hours after injury, peaking at 8 days, after which it gradually decreased. Two weeks after injury, EPO immunoreactivity was scarcely detected in neurons, whereas glial cells and vascular endothelium expressed strong EPO-R immunoreactivity. CONCLUSION:These observations suggest that the local EPO and EPO-R system is markedly engaged in the early stages after nervous tissue injury. The reduction in EPO immunoexpression and the increase in EPO-R staining strongly support the possible usefulness of a therapeutic approach based on exogenous EPO administration.

Erythropoietin Receptor Expression in Canine Mammary Tumor: An Immunohistochemical Study

Erythropoietin (EPO) is a cytokine primarily involved in the regulation of the erythropoiesis. Recently, it has been demonstrated that EPO and its receptor (EPOR) are expressed in several neoplastic cell lines and solid tumors. Furthermore, in vitro and in vivo studies have shown that EPO could promote human breast carcinoma growth by means of the binding with its receptor, although a clear function for EPO in this setting has not been yet established. While the human medical literature has been accumulating strong evidence on EPOs role in oncogenesis, to date, there are no veterinary reports focusing on such an issue. The aim of the present study was to investigate the immunohistochemical expression of EPOR in canine mammary gland dysplastic and neoplastic lesions. Our results show a weak to moderate EPOR expression in dysplastic glands, being immunoreactivity enhanced as the lesion shows an increasing malignant pattern. On the basis of these findings, this study describes, for the first time, the evidence for EPOR expression in canine mammary gland tumor and suggests a feasible EPOs role for canine mammary tumor progression.

Acquired melanosis caused by acorn ingestion in the Nero Siciliano pig.

In this study, an acquired pigmentation in Nero Siciliano pigs is reported and evaluated by a multidisciplinary approach to support the hypothesis it is caused by an ingested material. A total of 18 pigs were studied. Fourteen conventionally slaughtered animals showed black discoloration of lymph nodes. The lymph nodes were normal in size and shape but showed diffuse black discoloration of the cortex and medulla. Melanosis of fat was observed in 2 animals and was limited to the back. Histochemical tests performed on tissues enabled identification and differentiation of the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Stains for human melanoma, as well as S-100 protein, did not show any reaction. Histochemical methods for tyrosinase showed colorimetric patterns that confirmed the presence of the enzyme in acorns. The activity was mostly latent. A high tannin content was demonstrated, reaching about 76% of the total phenolic compounds. Our data, and the well-known steps on melanin formation, permit us to hypothesize that swine tyrosinase could act on phenolic substances found in acorns. Tyrosinase activation could take place in genetically predisposed swine after acorns are eaten, and this event could increase the biosynthesis and the anomalous storage of melanin.

Spontaneous schwannoma in zebrafish, Danio rerio (Hamilton).

Peripheral nerve sheath tumours (PNSTs) are neoplastic growths of the peripheral nerves and have been detected in almost all vertebrates. These tumours show either benign peripheral nerve sheath tumours (BPNSTs) or malignant peripheral nerve sheath tumours (MPNSTs) forms. PNSTs have been reported in many teleost species, generally as benign including goldfish, Carassius auratus (L.), (Picci 1933; Schlumberger 1952, 1957; Mawdesley-Thomas 1972), snappers (Lutjanidae) (Lucké 1942), coho salmon, Oncorhynchus kisutch (Walbaum) (Masahito, Ishikawa, Yanagisawa, Sugano & Ikeda 1985), damselfish, Pomacentrus partitus (Poey) (Schmale, Henseley & Udey 1983), rainbow smelt, Osmerus mordax (Mitchill) (Morrison, Harshbarger & McGladdery 1993), and gilthead seabream, Sparus aurata L. (Marino, Germanà & Panebianco 2008). Neurofibroma has been reported in Lumpenus sagitta (Wilimorsky) (McArn & Wellings 1967), C. auratus (Duncan & Harkin 1968), Gadus macrocephalus (Tilesius) (Wellings 1969), and striped mullet (Marino, Macrı̀, Lanteri, Manganaro, Monaco & Germanà 2010). The high expression and peculiar distribution of certain BPNSTs in some fish populations suggested a possible viral aetiology, so far demonstrated only for damselfish schwannoma (Schmale, Gibbs & Campbell 2002). Schwannoma and neurofibroma are the most common BPNSTs in humans, in domestic animals and in lower vertebrates such as teleostean fish. Schwannoma develop from the Schwann cells, whilst neurofibroma originates from fibroblast cells of the peripheral nerves. Despite their different origin, to distinguish schwannoma from neurofibroma was a diagnostic problem for many years and some authors preferred to consider them as a single morphological entity (Cordy 1990; Scarpelli 1969; Jubb & Huxtable 1993; Bambir, Helgason, Marino & Macrı̀ 2000). It can be difficult to differentiate these two tumours from fibromas (Scarpelli 1969). Although ultrastructural features have been used to differentiate schwannomas from neurofibromas (Duncan & Harkin 1969), immunohistochemistry has also been proposed as useful diagnostic tool in fish (Marino, Germanà, Bambir, Helgason, De Vico & Macrı̀ 2006; Marino et al. 2008). Recently, zebrafish mutants for the MMR genes mlh1, msh2 and msh6 have been isolated and homozygous mutants of all three lines develop neurofibromas/MPNST (Feitsma, Kuiper, Korving, Nijman & Cuppen 2008). The role of NF2 and p53 mutations in tumourigenesis has been emphasized by the observation of MPNST development in NF2 (Amsterdam, Sadler, Lai, Farrington, Bronson, Lees & Hopkins 2004) and p53 (Berghmans, Murphey, Wienholds, Neuberg, Kutok, Fletcher, Morris, Xi Liu, Schulte-Merker, Kanki, Plasterk, Zon & Look 2005) mutant zebrafish. tp53-deficient zebrafish lines, after 8.5 months, spontaneously develop Journal of Fish Diseases 2012, 35, 239–242 doi:10.1111/j.1365-2761.2011.01335.x

Mast cells in canine mammary gland tumour: number, distribution and EPOR positivity

Erythropoietin (EPO)-mediated mitogenic and anti-apoptotic effects involve all the cells expressing functional receptors for EPO (EPOR), as demonstrated by in vitro and in vivo studies. EPO shows pleiotropic effects and acts as an endogenous mediator of adaptive tissue response to metabolic stress protecting tissues from different injuries. Recently, the EPO/EPOR complex has been identified in several neoplastic cell lines and solid tumours. In this study, the authors investigated the mast cells (MCs) number, distribution and their immunoreactivity for EPOR in normal, dysplastic and neoplastic canine mammary gland. The results showed that MCs were more numerous in displastic glands compared with normal and neoplastic glands. As far as the EPOR immunoreactivity is concerned, we did not observe MCs reaction on cancer, in contrast with previously published data where epithelium of neoplastic gland showed an increase in EPOR expression along with the neoplastic progression. Overall, our results might be suggestive for MCs role in oncogenesis and offer new insight regarding to the expression of EPOR in mammary gland cancer in dog.

A Case of Conjoined Cephalopagus Twinning in an Ostrich (Struthio camelus)

Conjoined twinnings have been reported in most domestic animal species and in some avian species. Cases of conjoined twins have not been reported in the ostrich so far. A hybrid Blue neck × African black male ostrich conjoined twinning was born at the end of artificial egg incubation and died spontaneously 24 h after the hatching. It was frozen and sent to the Unit of Veterinary Pathology of the University of Messina for gross examination. The most important gross findings involved the external body and most of the internal organs. On the basis of the duplication, the conjoined twins were classified as a cephalopagus. Radiological features included: development of one head containing a single brain, two spinal cords, deviated vertebral columnae with fusion of the two first cervical vertebrae. In one twin, the synsacrum was absent as well as portions of the vertebral column. Grossly, both twins showed two upper and lower limbs each. The gastro‐enteric apparatuses of the twins were not completely developed and fused at different levels. One liver and one heart localized in the centre of the conjoined twins were observed. The authors conclude that the possible causes of the malformation could be related to a genetic factor.

Experimentally induced melanin-like pigmentation (thesaurismosis) related to acorn ingestion in Nero Siciliano pigs

In this study, an experimental challenge was carried out by feeding Nero Siciliano pigs with acorn to evoke melanin-like pigmentation and support the hypothesis that it is caused by ingested material. Twelve pigs were studied, 6 fed with acorns and 6 fed commercial feed. At slaughter, all the animals fed on acorns showed black discolouration of almost all lymph nodes. The lymph nodes were normal in size and shape. Histochemical tests performed on tissues allowed us to identify and differentiate the pigment. Immunohistochemical staining for macrophage markers showed macrophages containing a variable amount of melanin-like granules. Our data, and the well-known steps of melanin formation, confirm that swine enzymes could act on phenolic substances found in acorns.

Nervous control of photophores in luminescent fishes

Functional studies of the autonomic innervation in the photophores of luminescent fishes are scarce. The majority of studies have involved either the stimulation of isolated photophores or the modulatory effects of adrenaline-induced light emission. The fish skin is a highly complex organ that performs a wide variety of physiological processes and receives extensive nervous innervations. The latter includes autonomic nerve fibers of spinal sympathetic origin having a secretomotor function. More recent evidence indicates that neuropeptide-containing nerve fibers, such as those that express tachykinin and its NK1 receptor, neuropeptide Y, or nitric oxide, may also play an important role in the nervous control of photophores. There is no anatomical evidence that shows that nNOS positive (nitrergic) neurons form a population distinct from the secretomotor neurons with perikarya in the sympathetic ganglia. The distribution and function of the nitrergic nerves in the luminous cells, however, is less clear. It is likely that the chemical properties of the sympathetic postganglionic neurons in the ganglia of luminescent fishes are target-specific, such as observed in mammals.