Biomedical subjects

R Fatzer

Publications and source records attributed to R Fatzer.

At least 37 records · Page 2Linked to original sources

PubMed1999

Validation of a western immunoblotting procedure for bovine PrP(Sc) detection and its use as a rapid surveillance method for the diagnosis of bovine spongiform encephalopathy (BSE).

In this report we document the results of several independent studies testing the sensitivity, specificity and reliability of the Prionics Western blotting (PWB) procedure to detect bovine and ovine disease-specific, protease-resistant prion protein (PrP(Sc)). Validation of the technique was obtained by blind analysis of samples from cattle affected with bovine spongiform encephalopathy (BSE), clinically normal animals or cattle with neurological diseases unrelated to BSE. Overall, very high sensitivity, specificity and reliability was observed. It became clear that sampling of the correct brain region and the method used for protein extraction are important factors for correct diagnosis. Furthermore, we tested the usefulness of the PWB technique as an instrument for surveillance purposes. We analyzed animals from a culling scheme as well as older animals from abattoirs to determine the number of subclinical BSE cases detectable by histopathological examination, immunohistochemistry for PrP(Sc) and PWB. In both studies, BSE-affected animals with no overt clinical symptoms were detected. These results demonstrate the usefulness of the PWB procedure in surveillance systems serving as a rapid diagnostic tool to identify animals subclinically infected with BSE.

Animals↗

PubMed1999

Nuclear DNA fragmentation and immune reactivity in bovine spongiform encephalopathy.

To investigate whether apoptosis contributes to neuronal degeneration in bovine spongiform encephalopathy (BSE), morphological changes consistent with apoptosis were sought and in-situ end labelling (ISEL) was applied, in a series of 20 BSE cases and 10 age-matched normal control cattle. Apoptotic changes were not found in neurons but were occasionally seen in glial cells. Relatively few ISEL-positive neurons were found, but many labelled nuclei were seen in glial cells in certain areas. None of the labelled cells showed morphological features of apoptosis. ISEL(+)cells occurred in areas of spongiform change and other areas of grey matter lacking spongiform change. Some association was found between degree of cellular DNA fragmentation and accumulation of abnormal prion protein (PrP(Sc)). Interestingly, small or moderate numbers of T lymphocytes, not present in the normal central nervous system (CNS), were detected in the CNS parenchyma in most BSE cases. There was a pronounced astrogliosis, but markers of macrophage or microglial activation were only slightly increased. The results indicate that nuclear DNA vulnerability is enhanced in certain neuroanatomical areas in BSE, but evidence that apoptosis plays a role in neuronal loss in BSE was very limited. 1999 Harcourt Publishers Ltd.

Animals↗

PubMed1999

Detection of bovine spongiform encephalopathy-specific PrP(Sc) by treatment with heat and guanidine thiocyanate.

The conversion of a ubiquitous cellular protein (PrP(C)), an isoform of the prion protein (PrP), to the pathology-associated isoform PrP(Sc) is one of the hallmarks of transmissible spongiform encephalopathies such as bovine spongiform encephalopathy (BSE). Accumulation of PrP(Sc) has been used to diagnose BSE. Here we describe a quantitative enzyme-linked immunosorbent assay (ELISA) that involves antibodies against epitopes within the protease-resistant core of the PrP molecule to measure the amount of PrP in brain tissues from animals with BSE and normal controls. In native tissue preparations, little difference was found between the two groups. However, following treatment of the tissue with heat and guanidine thiocyanate (Gh treatment), the ELISA discriminated BSE-specific PrP(Sc) from PrP(C) in bovine brain homogenates. PrP(Sc) was identified by Western blot, centrifugation, and protease digestion experiments. It was thought that folding or complexing of PrP(Sc) is most probably reversed by the Gh treatment, making hidden antigenic sites accessible. The digestion experiments also showed that protease-resistant PrP in BSE is more difficult to detect than that in hamster scrapie. While the concentration of PrP(C) in cattle is similar to that in hamsters, PrP(Sc) sparse in comparison. The detection of PrP(Sc) by a simple physicochemical treatment without the need for protease digestion, as described in this study, could be applied to develop a diagnostic assay to screen large numbers of samples.

Animals↗

PubMed1999

[Multiple cranial nerve deficits after eye injury and eye enucleation. A case report].

A 12-year old Simmental x Red Holstein cow was admitted to the clinic eight months after an eye laceration followed by eye extirpation. The region of the excised eye had healed, however, the cow had additional trigeminal and facial nerve palsy. Nevertheless, the cow was in good general condition, and therefore, was sent home without therapy. After delivering a sound calf, her physical condition deteriorated and she was slaughtered. Histologic examination of the brain revealed degeneration of the right optic nerve and right half of the chiasma opticum as well as left tractus opticus (opposite side); furthermore, degenerative changes with slight inflammation of the right vestibular nuclei were observed. Possible pathogenesis is discussed.

Animals↗

PubMed1998

Neuropathological and aetiological studies of sporadic non-suppurative meningoencephalomyelitis of cattle.

Sporadically occurring non-suppurative encephalitis appears to be a frequent condition of Swiss cattle. Fifty-one such cases diagnosed over a period of 10 years were examined retrospectively to investigate whether they constituted one or more distinct diseases, and to search for aetiological agents. Three cases were characterised by periventricular granulomatous encephalitis, and most probably represented a different disease, but the remaining 48 cases had disseminated non-suppurative encephalitis with widespread neuronal changes. Neuronal degeneration was very marked in the hippocampus of 10 cases and in the cerebellar Purkinje cells of 11. It was thought that the latter cases represented morphological variations of the same disease rather than a different disease because of their overlapping morphological features. The 48 cases had the following features in common: the disease had primarily neurological signs affecting mostly adult cattle, it was a sporadic condition, and there was a clear tendency for it to have a subacute to chronic course. Polymerase chain reaction (PCR) amplification for chlamydial DNA was negative except in one of 32 specimens, and immunohistochemistry did not demonstrate the presence of chlamydial antigens either in the one PCR-positive case or in the other cases examined. Immunohistochemistry for rabies virus, Borna disease virus, and central European tickborne encephalitis virus was negative. In four cases, immunolabelled cells were found in the lesions with antibodies against paramyxovirus antigens.

Animals↗

PubMed1998

[Convulsions in relation to polycythemia: literature review and case description].

Polycythemia--characterized by an excessive number of erythrocytes--is a rare disease in the dog with a chronic progressive course and unspecific symptoms. There are several forms: a primary, a secondary adequate or a secondary inadequate polycythemia. The clinical workup is done step by step and after stabilization of critical patients, the remaining therapy must address the primary cause. We report on a five year old male Leonberger dog suffering from secondary, inadequate polycythemia. He was presented with apathy, gait disturbances and disorientation. On the basis of the diagnostic workup a pathological process in the kidneys was postulated. Initially focal seizures became generalized later, most probably because of formation of a forebrain thrombus with secondary hypoxia. Even after emergency treatment the general state deteriorated. The course indicated possible sepsis. Because of the critical picture with secondary complications and the poor prognosis, the dog was euthanised. The histopathological results showed T-cell renal lymphoma and secondary injury to the forebrain.

Animals↗

PubMed1998

[Transmissible spongiform encephalopathies in animals].

Transmissible spongiform encephalopathies in animals are known for centuries. In particular scrapie in sheep and goats occurs worldwide; it spreads as a natural disease and is genetically controlled. Chronic wasting disease (CWD) in the United States (Wyoming and Colorado) also spreads as natural disease among free ranging and captive elk and mule deer. In contrast, transmissible mink encephalopathy (TME) of mink in fur producing farms is caused by contaminated feed; the source of this food contamination is still controversial. The only occurrence of a TSE in an avian species was reported from a flock of ostriches in a German zoo. The origin of the outbreak of bovine spongiform encephalopathy (BSE) in Great Britain could be traced back to feeding concentrates containing animal proteins contaminated with the agent of sheep scrapie. BSE was introduced into other countries, e.g. Switzerland and France, through the import of contaminated feeds from Great Britain. In addition, sporadic cases of TSE occurred in 10 other species, in particular domestic cats and zoo animals, e.g. antelopes and large cats. The diagnosis is based on the neuropathological examination of the brain as well as the demonstration of the disease specific protease resistant prion protein (PrPres). The first measures against the disease aim at eliminating the risk factors. The most important is the prohibition of feeding animal protein concentrates to ruminants. Thanks to this measure the incidence of BSE diminished remarkably. To protect consumers of beef products, in countries with BSE the potentially infectious organs of all cattle are confiscated at slaughter. Yet, in Great Britain this measure was introduced only at a point of time when BSE had already spread all over the country. Therefore, there is a strong probability of an exposition of consumers of beef with the BSE agent, which might have caused the new variant of Creutzfeldt-Jakob disease (nvCJD).

Animal Feed↗

PubMed1998

[182 offspring of cows with bovine spongiform encephalopathy (BSE) in Switzerland. 2. Epidemiology and pathological findings].

In order to detect lesions of a spongiform encephalopathy and/or accumulation of the protease resistant prion protein (PrPres), 182 offspring of cows affected with BSE were examined neuropathological and immunohistochemically. Neither spongiform encephalopathy nor PrPres accumulation were found. In seven animals other neuropathological lesions were seen, significant ones in three. Because of the small risk of exposure to contaminated feed in these animals, nearly all of which were born after the introduction of the protein feed ban for ruminants, the occurrence of spongiform encephalopathy in this series of BSE offspring would be suggestive of maternal transmission. However, the value of the study in this respect is quite limited. Only half of the animals were old enough to develop clinical and pathological evidence of the disease. If a maternal effect on the risk for the offspring is only to be expected during the last 6 months of the incubation of the dam as suggested by British investigations, only few animals in this study would fulfil the requirement of having been born during this critical period. Since it cannot be entirely excluded that the BSE agent transiently invades extraneural tissues in the early stages of infection, the above mentioned restriction to the final 6 months of the incubation time of the dam would not necessarily be applicable to all situations. We concluded that this study supports previous observations according to which maternal transmission of BSE is at best a rare event.

Animals↗

PubMed1997

Hydrocephalus with periventricular encephalitis in the dog.

A 3-month-old female Dalmatian dog and a 2.5-month-old Poodle dog were referred with a sudden onset of neurological syndrome consistent with hydrocephalus. Clinical signs included depression, severe ataxia, eye abnormalities and skull enlargement in one case. Postmortem examination revealed severe internal hydrocephalus with cavitation of the cerebral white matter associated with necrotizing and inflammatory lesions of the periventricular nervous tissue. Although no bacteria were isolated from cerebrospinal fluid and no infectious agents were detected in the brains, an infectious etiology was postulated.

Animals↗

PubMed1997

Comparison of inducible nitric oxide synthase expression in the brains of Listeria monocytogenes-infected cattle, sheep, and goats and in macrophages stimulated in vitro.

The expression of inducible nitric oxide synthase (iNOS) was studied in the brains of cattle, sheep, and goat that succumbed to a natural infection with Listeria monocytogenes. The lesions in infected brains are characterized by microabscesses, perivascular cuffs, gliosis, glial nodules, and large areas of malacia. Using immunocytochemistry, we detected bacteria in microabscesses, particularly in sheep and goats, and in areas without signs of inflammation, but not in perivascular infiltrates. iNOS was expressed by macrophage (Mphi)-type cells of microabscesses and glial nodules but rarely by Mphi in areas of malacia, as determined by immunohistochemistry with iNOS-specific antibodies. iNOS was not detected in perivascular cuffs. Major histocompatibility complex class II molecules (MHC-II), another marker of cell activation, showed a different pattern of distribution. Perivascular cuffs contained high numbers of MHC-II-positive cells, including some with Mphi characteristics. Microabscesses in sheep and goats showed low expression of MHC-II, particularly in iNOS-expressing cells. In cattle, the expression of markers for activated or recruited phagocytes, the calcium-binding proteins S100A8 and S100A9 (formerly called MRP-8 and MRP-14, respectively), was largely restricted to cells showing weak or undetectable iNOS expression; iNOS-positive Mphi showed a low expression of S100A8 and S100A9. Thus, iNOS is expressed by a restricted subset of Mphi in listeric encephalitis. In cultured sheep and goat Mphi, a low proportion of cells expressed iNOS upon activation by L. monocytogenes and gamma interferon, resulting in nitrite generation at least 1 order of magnitude lower than that in similarly treated cattle Mphi. Since these species differences were much less obvious in vivo, it appears that the well-known species variation in iNOS expression by Mphi could reflect an in vitro phenomenon.

Animals↗

PubMed1997

Neuronal vacuolation and spinocerebellar degeneration in young Rottweiler dogs.

With the recent epizootic of bovine spongiform encephalopathy in Europe, the differential diagnosis of neuronal vacuolation and spongiform change in other species has become critically important. Four Rottweiler puppies of both sexes, presented at 3-8 months of age, had clinical signs of generalized weakness and ataxia that started at 6 weeks of age. In all pups, neurologic examination detected an ataxia and tetraparesis, most severe in the pelvic limbs, and slowed proprioceptive placing reactions. Subsequently, there was rapid progressive neurologic deterioration, with severe placing deficits, knuckling, severe ataxia, and quadraparesis by 8 months of age. At necropsy, no gross lesions were observed. Microscopic lesions were restricted to the nervous system. The major lesion in all dogs was an intracytoplasmic neuronal vacuolation that was most prominent in the cerebellar roof nuclei and in nuclei of the extrapyramidal system. Similar vacuolation was found in neurons in both dorsal nerve root ganglia, myenteric plexus, and other ganglia of the autonomic nervous system. The single or multiple empty vacuoles were between 1 and 45 microm in diameter. A mild spongiform change was seen in the adjacent neuropil. Purkinje cell vacuolation and degeneration with segmental cell loss was seen in the oldest dog. In ventromedial and dorsolateral areas of the spinal cord white matter, there was mild bilaterally symmetrical axonal degeneration. Immunoblotting and immunocytochemical staining of the brain for protease-resistant scrapie prion protein was negative. All forms of vacuoles were negative for immunohistochemical staining with a variety of lectins. Ultrastructurally, the vacuoles were bound by a single membrane and contained granular material and sometimes membranous profiles. There was mild distension of the cytocavitary network but no unequivocal connection with the vacuoles was found. Axosomatic and axodendritic synapses in affected neurons were intact both ultrastructurally and with synaptophysin immunostaining. The clinicopathologic findings were different from those seen in the other neurologic diseases of Rottweilers. The age of the dogs, distribution and type of the lesions, ultrastructural findings, and negative immunoblotting most likely rule out the possibility of a scrapie agent-associated spongiform encephalopathy. However, the etiology of this new disease was not determined.

Animals↗

PubMed1997

[Frequency of neurologic diseases in cattle].

The cases of neurological diseases at the Institute of Animal Neurology, University of Berne, from 1985-1994 were assessed. During this period 532 cattle with neurological symptoms were examined. After 1980 differential diagnostic investigation of rabies negative brains were not pursued anymore and the number of examined cattle brains had declined to 25-30 per year. With the occurrence of bovine spongiform encephalopathy (BSE) in 1990 in Switzerland the number of cattle brains examined has increased to 75-80 yearly. The most frequently diagnosed neurological diseases found are BSE, followed by listeriosis and viral encephalitides.

Animals↗

PubMed1996

Neuronal degeneration in brain stem nuclei in bovine spongiform encephalopathy.

In 57% of 151 BSE positive brains of Swiss cattle, degenerating neurons were found in BSE predilection sites, either single scattered (34%) or involving large parts of brain stem nuclei (23%). The lesion consisted of central chromatolysis, shrinkage, karyolysis or nuclear pyknosis. In 43% of the BSE positive brains no neuronal changes besides vacuolation were present. Neuronal degeneration other than vacuolation alone is not pathognomonic for BSE but, according to our findings, seems to be of some importance together with the typical vacuolation of neuropil and neurons. There is no correlation between extent of these degenerative changes and accumulation of PrPSc protein, determined by immunohistochemistry. The significance remains obscure, yet as it had not been seen in cattle brains before the outbreak of BSE in Switzerland in 1990 it certainly is linked to the disease. Possible pathogenetic mechanisms are discussed.

Animals↗

PubMed1996

[Reference values of electrodiagnostic and laboratory studies in young Wallis Schwarzhals goats].

Laboratory testing in 10 "Walliser Schwarzhals"-goats included red and white blood cell count, electrolytes, liver enzymes, trace elements and urinalysis, protein determination and cell count of the cerebrospinal fluid (CSF) was also performed. Electrodiagnostic testing included electromyography (EMG) of the head and spinal muscles, motor nerve conduction velocity (MNCV) of the right and left peroneal nerve, brainstem auditory evoked potentials (BAEP) and electroencephalography (EEG). MNCV of the peroneal nerve was 72 +/- 9.24 m/s. Latency and amplitude of the BAEP for P1 was 2.15 +/- 0.08 ms respectively 2.23 +/- 0.7 microV and for P5 5.09 +/- 0.15 ms respectively 0.68 +/- 0.24 microV. P2 (3.2 +/- 0.14 ms/1.37 +/- 0.32 microV) and P3 (3.9 +/- 0.13 ms/0.84 +/- 0.14 microV) were equally distributed between P1 and P5. Whereas the results of EMG and BAEP were similar to those of other species, the electroencephalographic findings consisted of three different patterns depending on duration and depth of isofluran anesthesia. Pattern I had a rhythmic high amplitude (80 microV) and low frequency (1-2 Hz) pattern with aperiodic intervals of relative electric silence. Pattern II was characterized by increased duration of HALF (150 microV), associated with spindles of low amplitude (20-30 microV) and high frequency (10 Hz). Pattern III had generalized delta-activity of high amplitude (70-200 microV). All the results are discussed briefly.

Animals↗

PubMed1995

In situ hybridization and immunohistochemistry for prion protein (PrP) in bovine spongiform encephalopathy (BSE).

In about 5% of the cows showing clinical signs of bovine spongiform encephalopathy (BSE) the histopathological examination is not conclusive. In order to rule out BSE in these cases, additional methods are necessary. For that reason, non-radioactive in situ hybridization (ISH) was performed using a riboprobe against the messenger RNA coding for the prion protein (PrP). In addition, a polyclonal antibody for immunohistochemistry (IHC) was generated against a synthetic peptide derived from bovine PrP. ISH and IHC were used to analyse brain sections of cattle suffering from BSE and various neurological diseases including four cows with clinically suspect but histologically unconfirmed BSE. ISH revealed no differences in localization, distribution and neuronal levels of PrP mRNA between BSE positive and negative cattle. However, there was a BSE-specific staining pattern in IHC allowing to exclude BSE the four suspected cases. Additionally, IHC for PrP is an elegant alternative to search for scrapie associated fibrils by electron microscopy.

Animals↗

PubMed1995

[Examination of the brains of slaughtered cattle for the occurrence of BSE in Italy with attention to non-specific neuronal vacuoles].

In order to find out whether BSE exists in Italy 378 brains of normally slaughtered 2-10 years old cattle submitted from slaughterhouses all over the country were examined histologically. None showed the typical lesions of BSE. About 11.5% of the brains contained large vacuoles in the neurons of brain stem nuclei, in particular the red nucleus in the midbrain. They were considered non specific.

Abattoirs↗

PubMed1995

Neuronal vacuoles in the canine brain.

Intraneuronal vacuoles have been observed in the motor trigeminal nucleus of the medulla oblongata of two dogs which showed neurological deficits. Its significance and possible relation with the same lesions observed in other animal species are discussed.

Animals↗

PubMed1992

[Spongiform encephalopathies with special reference to bovine spongiform encephalopathy].

In Switzerland bovine spongiform encephalopathy (BSE) was detected for the first time in November 1990. It is a transmissible disease of the central nervous system similar to Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS) and kuru in man, and, in animals, scrapie in sheep and goats, chronic wasting disease (CWD) in captive mule deer and elk of North America and transmissible mink encephalopathy (TME) of farm reared mink. The infectious agent of the spongiform encephalopathies (SEs) is extremely small (greater than 100 microns) and very resistant against physical and chemical disinfectants. The infectiousness is closely linked to the so-called prion proteins, the biological and genetic properties of which are not yet fully understood. The first outbreak of BSE occurred in England, and the disease spread rapidly all over Great Britain. The source of infection proved to be bone and meat meal obtained from scrapie-infected slaughter wastes. So far we have diagnosed 17 cases of BSE in our country. The risk of humans contracting CJD by ingestion of meat, milk and their products contaminated with BSE is probably minimal.

Animals↗