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Biomedical subjects

G Di Guardo

Publications and source records attributed to G Di Guardo.

At least 19 recordsLinked to original sources
PubMed2006

PrP(Sc) deposition in nervous tissues without lymphoid tissue involvement is frequently found in ARQ/ARQ Sarda breed sheep preclinically affected with natural scrapie.

The pathogenesis of natural scrapie in Sarda breed sheep was investigated in 1050 asymptomatic and 49 sick sheep from scrapie-affected flocks. Central and peripheral nervous system, along with lymphoreticular system (LRS) tissues, were subjected to immunohistochemistry (IHC) and Western-blotting (WB) for detection of pathological isoform of the prion protein (PrP(Sc)). A total of 69 of the 1050 clinically healthy sheep were found to be infected with scrapie, with PrP(Sc) being detected in both the central nervous system (CNS) and enteric nervous system (ENS) plexuses of 60 of the sheep, while IHC and WB yielded evidence of (PrP(Sc)) deposition only in lymphoid tissues of the remaining 9 clinically healthy sheep. PrP(Sc) was also detected in the CNS, as well as in ENS plexuses from all of the 49 clinically affected sheep. Nevertheless, 18 of the 69 clinically healthy animals (26%, 17 ARQ/ARQ and 1 ARQ/AHQ sheep), along with 3 ARQ/ARQ sheep (6%) of the clinically affected group, showed no IHC or WB evidence of PrP(Sc) in lymphoid tissues, but PrP(Sc) could be still detected in their CNS and ENS plexuses. The study demonstrates dual CNS and ENS PrP(Sc) deposition in Sarda sheep with scrapie, in spite of an apparent lack of lymphoid tissue involvement in a number of cases.

Animals↗
PubMed2005

Spontaneous ocular squamous cell carcinoma in twin goats: pathological and biomolecular studies.

Ocular squamous cell carcinoma (OSCC) is a well-characterized tumour occurring spontaneously in cattle and other mammalian species but not previously reported in the goat. This report describes the histological features of well-differentiated OSCCs in twin goats. Biomolecular investigations led to the identification of Papillomavirus-related DNA sequences within the neoplastic ocular parenchyma of both animals, but immunohistochemical and ultrastructural studies failed to demonstrate viral particles. A putative role of Papillomavirus in the aetiology of OSCC is discussed, together with other possible causative factors.

Animals↗
PubMed2005

Morbillivirus infections in aquatic mammals: a brief overview.

Since 1987, at least eight morbillivirus infection (MI) epidemics have caused mass mortality of several free-living pinniped and cetacean populations around the world. The responsible agents, all belonging to the genus Morbillivirus (family Paramyxoviridae), have been characterized as either "canine distemper virus" strains, infecting pinnipeds, or as three new morbilliviruses, namely "phocid (phocine) distemper virus" , "porpoise morbillivirus" and "dolphin morbillivirus" . The last two agents are currently gathered under the common denomination of "cetacean morbillivirus". At post-mortem examination, a commonly occurring macroscopic lesion is represented by more or less severe bilateral pneumonia, with consolidation, congestion and oedema of both lungs, which fail to collapse. Histologically, a non-suppurative broncho-interstitial pneumonia, characterized by type II pneumocyte hyperplasia and by formation of endobronchial, endobronchiolar and endoalveolar "Warthin-Finkeldey type" syncytia, as well as a multifocal, non-suppurative encephalitis, associated with a severe and generalized lymphoid tissue depletion, are common pathological findings. Furthermore, eosinophilic viral inclusions are often detected, at both the intracytoplasmic and intranuclear level, within bronchial and bronchiolar epithelial, pulmonary syncytial, neuronal and other cell types. These inclusions, along with lymphoid and other cellular elements, are often found to be immunohistochemically positive for morbillivirus antigen. Among the still debated, or even controversial issues regarding MI in sea mammals, the one related to the origin of their causative agents is of particular concern. Another intriguing issue regards the synergistic effects, if any, associated with chronic exposure to a number of environmental pollutants, such as organochlorines and heavy metals. In fact, it is also unknown whether and how these chemicals contribute towards modulating the pathogenic and pathogenetic activity primarily displayed by sea mammal morbilliviruses.

Animals↗
PubMed2005

Benign giant cell tumour of tendon sheaths in a European Lynx (Lynx lynx).

The histological, histochemical, immunohistochemical and ultrastructural features of a benign giant cell tumour (BGCT) of tendon sheaths in a 12-year-old male European lynx (Lynx lynx) are reported herein. The neoplastic mass involved the subcutaneous and inter-muscular tissues of the first, second, third and fourth digit of the left forelimb, from the phalanxes up to the carpus. The tumour appeared as a grey-whitish tissue mottled with darker areas, along with several scattered foci of orange colour. Histologically, the lesion consisted of a mixed population of numerous, multinucleated giant cells and epithelioid or spindle-shaped mononuclear cells embedded in a loose, highly vascular stroma. Neoplastic cells lined cleft formations and synovial-like projections into cystic spaces. No osteoid matrix could be detected. Haemorrhage and necrosis were also observed. The mononuclear and the giant cells were tartrate-resistant acid phosphatase and periodic acid-Schiff positive, being also immunohistochemically reactive for lysozyme and vimentin, with a few cells showing immunopositivity also for alpha-1-antitrypsin. Ultrastructurally, histiocyte-like cells, fibroblast-like cells and multinucleated giant cells were observed, but no virus-like particles could be detected in any of the above cell types. The BGCT of tendon sheaths, a fairly uncommon neoplasm in animals, has not been previously reported in the lynx.

Animals↗
PubMed2005

Heterotopic kidney tissue in the lung of a free-living common dolphin (Delphinus delphis).

A spontaneous case of renal heterotopia involving the lung parenchyma of a free-living, adult, female common dolphin (Delphinus delphis), which was found stranded alive on the North Adriatic Sea coast of Italy, is reported in this study. The lesion, slightly visible from the macroscopic point of view, had the histologic appearance of a "foreign tissue island," which was poorly demarcated from the surrounding pulmonary tissue. Within such an island, several regularly shaped and apparently mature kidney glomeruli and tubules could be observed, with no evidence of secondary tissue reaction. To the best of our knowledge, this should be the first description of heterotopic kidney tissue occurrence in the lung of any domestic or wild animal species.

Animals↗
PubMed2004

Heat shock proteins (HSPs) 27, 72 and 73 in normal and pre-ulcerative mucosa of the gastric pars oesophagea in swine.

Heat shock proteins (HSPs), known to play a key role in cellular homeostasis, may also play a role in the defensive mechanisms of gastric mucosa. By means of appropriate immunohistochemical and immunobiochemical techniques, the expression of HSP27, HSP72 and HSP73 within the epithelium of normal and pre-ulcerative (hyperkeratinized) mucosa of the pars oesophagea of abattoir pigs was assessed. In normal mucosa, HSP72 and HSP73 expression was mainly limited to the basal epithelial cell layer, whereas HSP27 expression was consistently detected within the superficial epithelial cell layers. In hyperkeratinized mucosa, HSP72 and HSP73 immunoreactivity appeared to be more widespread, becoming very intense within epithelial cells affected by hydropic degeneration. Hyperkeratinized mucosa also showed HSP27 immunoreactivity, which was particularly intense in epithelial areas affected by hydropic degeneration. Western blot analysis confirmed HSP27, HSP72 and HSP73 expression in normal and in pre-ulcerative mucosa of the pars oesophagea. Semi-quantitative analysis showed that for all three HSPs the immunoreactivity was more intense in pre-ulcerative mucosa than in normal mucosa. The different expression patterns observed may have functional significance; further studies are needed, however, to define the role of HSPs in swine oesophagogastric lesions, the aetiology and pathogenesis of which are largely unknown.

Animals↗
PubMed2004

Primer extension assay for prion protein genotype determination in sheep.

Scrapie is a transmissible spongiform encephalopathy (TSE) which affects sheep and goats. TSEs are characterised by the conversion of the cellular prion protein (PrP(C)) into the pathological form PrP(Sc). The occurrence of scrapie in sheep is influenced by polymorphisms in the PrP gene; in particular, three codons (136, 154 and 171) are important in conditioning the susceptibility/resistance of sheep to the disease, with the Val/Val(136) Arg/Arg(154) Gln/Gln(171) genotype being the most susceptible and the Ala/Ala(136) Arg/Arg(154) Arg/Arg(171), the most resistant one. The latter genotype seems to confer, in sheep, resistance to the oral infection with bovine spongiform encephalopathy, as well. The selection of genetically resistant sheep populations represents the basis of the recent strategies against ovine TSE in the European Union (EU). Herein, we describe a rapid and simple method, based on the primer extension technique, for PrP genotype determination at codons 136, 154 and 171. Intra-laboratory validation of the method showed accuracy levels comparable to those of sequencing analysis. Such method could be used for both the application of the EU policies requiring PrP genotype analysis in all ovine TSE cases, and the large-scale genotyping claimed by the implementation of breeding programmes for genetic resistance to TSE in sheep.

Animals↗
PubMed2003

Animal transmissible spongiform encephalopathies and genetics.

The genotype of the host plays a crucial role in the pathogenesis of transmissible spongiform encephalopathies (TSEs). In this respect, the most important factor is represented by the gene of the prion protein (PrP). The present work summarizes the currently available knowledge on the genetic basis of TSEs focusing, in particular, on sheep scrapie. Interest in this disease has grown markedly following the discovery of bovine spongiform encephalopathy, both for scientific and health reasons. In Italy, specific research grants from the Ministry of Health and the National Research Council (CNR), together with cooperation between the Istituto Superiore di Sanità and the Istituti Zooprofilattici Sperimentali, have allowed us to study the PrP genotype and to investigate the genetic susceptibility to scrapie in the most important Italian sheep breeds, with special reference to Sarda, Comisana and Massese. The PrP genotype in relation to scrapie susceptibility was also studied in goats of Ionica breed.

Animals↗
PubMed2001

Genomic organization, comparative analysis, and genetic polymorphisms of the bovine and ovine prion Doppel genes (PRND).

The doppel protein (Dpl) is a prion-like protein encoded by the gene PRND, which has been found downstream of the prion gene, PRNP, in human and mouse. This paper describes the isolation and structural organization of the bovine and ovine PRND genes, which are composed of two exons compared with the three of human and mouse. Intergenic distances between PRNP and PRND were covered by means of long-range PCR and found to be 16.8 and 20 kb, in cattle and sheep respectively. The 5' and 3' untranslated regions (UTR) were analyzed to identify transcription regulatory sequences and compared with those from the PRND and PRNP sequences published for other species. Three polymorphisms (R50H, N110H, and R132Q) were revealed in the cattle coding region; two synonymous substitutions (I12I, A26A) were found in sheep. None of the polymorphisms was significantly associated with either Bovine Spongiform Encephalopathy (BSE) in cattle or scrapie in sheep.

Animals↗
PubMed2001

PrP genotype in Sarda breed sheep and its relevance to scrapie. Brief report.

Several PrP gene polymorphisms modulate sheep scrapie susceptibility. Recently, an increase of scrapie outbreaks has been reported in Italy. A vaccine containing sheep brain homogenate was used in most of the outbreaks. We investigated PrP gene polymorphisms in scrapie-affected and clinically healthy Sarda breed sheep from a flock exposed to the aforementioned vaccine, and in affected Sarda sheep from unexposed flocks. All affected animals were (Gln/Gln)171 homozygous. Moreover, we observed no variation for Ala136 and a new polymorphism (Lys to Asn) at codon 176. Our findings confirm the correlation between scrapie and (Gln/Gln)171 in breeds with no variation for Ala136.

Animals↗
PubMed2001

Pathologic and immunohistochemical findings in naturally occuring West Nile virus infection in horses.

The pathologic and peroxidase immunohistochemical features of West Nile flavivirus (WNV) infection were compared in four horses from the northeastern United States and six horses from central Italy. In all 10 animals, there were mild to severe polioencephalomyelitis with small T lymphocyte and lesser macrophage perivascular infiltrate, multifocal glial nodules, neutrophils, and occasional neuronophagia. Perivascular hemorrhages, also noted macroscopically in two animals, were observed in 50% of the horses. In the four American horses, lesions extended from the basal nuclei through the brain stem and to the sacral spinal cord and were more severe than the lesions observed in the six Italian horses, which had moderate to severe lesions mainly in the thoracolumbar spinal cord and mild rhombencephalic lesions. WNV antigen was scant and was identified within the cytoplasm of a few neurons, fibers, glial cells, and macrophages. WNV infection in horses is characterized by lesions with little associated antigen when compared with WNV infection in birds and some fatal human infections and with other important viral encephalitides of horses, such as alphavirus infections and rabies.

Animals↗
PubMed2001

[Fascicular ventricular tachycardia].

Fascicular tachycardia is an uncommon idiopathic ventricular tachycardia, originating from the left ventricle; it usually occurs in young male patients, with a high prevalence in south-east Asiatic people. Electrocardiographic aspects of this unique ventricular tachycardia (right bundle branch block morphology and left or right-axis deviation, with a moderate QRS widening) and verapamil sensitivity make it often difficult the differential diagnosis with other forms of supraventricular tachycardia. Reentry is believed to be the operative mechanism of fascicular tachycardia, with the reentrant circuit located in the Purkinje network, in the region of the left posterior or anterior fascicle. The slow conduction zone participating in the reentry circuit, made up of partially depolarized Purkinje fibers, seems to be located in a relatively wide area, from the basal to the apical left interventricular septum. Intravenous verapamil is elective in acute treatment; however oral verapamil shows poor efficacy in preventing tachycardia relapses. Ablative approach is very effective; success is achieved in approximately 90% of patients, with rare complications. Recently diastolic potentials during fascicular tachycardia have been reported and these findings have given rise to new electrophysiological hypotheses and new indications about the successful ablation site.

Age Factors↗
PubMed2000

Histopathological and immunohistochemical studies on cetaceans found stranded on the coast of Italy between 1990 and 1997.

Detailed histopathological and immunohistochemical studies were carried out on 24 cetaceans, 17 of which were striped dolphins (Stenella coeruleoalba), four bottlenose dolphins (Tursiops truncatus) and three Risso's dolphins (Grampus griseus), all found stranded on the Italian coast between 1990 and 1997. The most frequently detected lesions were chronic pneumonia (73.7% of the examined lungs), focal chronic pancreatitis (71.4%), non-purulent encephalitis (50%), chronic hepatitis (42.1%), and chronic focal interstitial nephritis (31.2%). The skin and the subcutaneous panniculus were often (33.3%) affected by parasitic diseases (Phyllobothrium delphini and Pennella sp.). An appreciable percentage of animals showed lymphoid depletion in their lymphatic organs (47.2%), as well as a high rate of parasitic infestations in their alimentary tracts (25%).

Animals↗
PubMed2000

Clinical and neuropathological features of West Nile virus equine encephalomyelitis in Italy.

West Nile (WN) virus infection is a mosquito-borne flavivirosis endemic in Africa and Asia. Clinical disease is usually rare and mild and only in a few cases the infection causes encephalomyelitis in horses, fever and meningoencephalitis in man. We report here the clinical and pathological findings in an epidemic of the disease involving 14 horses from Tuscany, Italy. All cases were observed from August to October 1998. Affected horses showed ataxia, weakness paresis of the hindlimbs and, in 6 cases, there was paraparesis progressing to tetraplegia and recumbency within 2 to 9 days. Eight animals recovered without any important consequences. Serological investigations revealed positivity to WN virus in all the 14 horses and the agent was isolated from the cerebellum and spinal cord of an affected horse. Postmortem examination was carried out on 6 horses. The neuropathological pattern was that of a mild to moderate, nonsuppurative polioencephalomyelitis with constant involvement of the ventral horns of the thoracic and lumbar spinal cord, where focal gliosis and haemorrhage were also apparent in some cases. Differential diagnoses with other equine viral encephalomyelitides are discussed. Climatological and environmental characteristics of the geographic area in which the outbreaks occurred suggest the existence of suitable conditions for the development of the disease. This is the first report of WN virus equine encephalomyelitis in Italy.

Animals↗
PubMed2000

Pulmonary protostrongyliasis in a mountain hare from Italy.

An adult male mountain hare (Lepus timidus), shot during the hunting season on the slopes of Mt. Civetta (eastern Alps, Veneto, northeastern Italy), was eviscerated and diffuse nodular lesions of verminous pneumonia were observed. Adult helminths were collected and male specimens were identified as Protostrongylus pulmonalis. Histologically, a non-purulent interstitial pneumonia and a desquamative bronchiolitis and alveolitis, along with thickening of alveolar septa, were apparent in the nodules. In several enlarged alveoli, a large number of eggs and larvae of nematodes were found. This is the first recorded case of protostrongyliasis in mountain hares from Italy and from an alpine population.

Animals↗
PubMed1999

Primary cilium expression in cells from normal and pathological caprine skin.

Primary cilia were detected in keratinocytes and fibroblasts, from the skin of two healthy and five Saanen goats suffering from a severe papillomatosis of the udder, respectively. Single cilia were detected in very few normal and neoplastic keratinocytes; rare biciliated keratinocytes were also seen. A remarkable number of dermal fibroblasts from healthy goats showed single cilia. Similarly, primary cilia were found in fibroblasts from the tumour stroma in all five goats. These data seem to strengthen the statement that ciliation is a peculiar ultrastructural aspect of fibroblasts, which is of interest in the light of the emerging role of fibroblasts in many physiopathological processes.

Animals↗