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A Buschmann

Publications and source records attributed to A Buschmann.

At least 19 recordsLinked to original sources
PubMed2006

Atypical BSE in Germany--proof of transmissibility and biochemical characterization.

Intensive active surveillance has uncovered two atypical German BSE cases in older cattle which resemble the two different atypical BSE phenotypes that have recently been described in France (designated H-type) and Italy (designated L-type or BASE). The H-type is characterized by a significantly higher molecular size, but a conventional glycopattern of the proteinase K treated abnormal prion protein (PrP(Sc)), while the L-type PrP(Sc) has only a slightly lower molecular size and a distinctly different glycopattern. In this paper we describe the successful transmission of both German atypical BSE cases to transgenic mice overexpressing bovine PrP(C). Upon challenge with the L-type, these mice developed BSE after a substantially shorter incubation period than any classical BSE transmission using these mice to date. In contrast, the incubation period was distinctly prolonged when these mice were challenged with the H-type. PrP(Sc) accumulated in the brains of these mice were of the same atypical BSE type that had been used for the transmission. These atypical cases suggest the possible existence of sporadic BSE cases in bovines. It is thus feasible that the BSE epidemic in the UK could have also been initiated by an intraspecies transmission from a sporadic BSE case.

Amino Acid Sequence↗
PubMed2006

Synthetic prions.

The prion theory postulates that prions are novel infectious agents that are composed largely, if not entirely, of abnormally folded host-encoded prion proteins. However, the existence of different prion strains is enigma, if these novel infectious agents lack a genetic element, such as a nucleic acid. The best proof for this 'protein-only' concept would be the in vitro generation of prions from synthetic sources. Indeed, a substantial body of evidence has meanwhile been accumulated in favour of this postulate. This mini review recapitulates all relevant studies and experimental data on the generation of synthetic prions.

Animals↗
PubMed2005

Strain typing of German transmissible spongiform encephalopathies field cases in small ruminants by biochemical methods.

Following the implementation of a large scale transmissible spongiform encephalopathies (TSE) surveillance programme of small ruminants, evidence for a natural transmission of bovine spongiform encephalopathy (BSE) to a French goat has been found. During the years 2002-2004, a massive TSE rapid testing programme on >250,000 small ruminants was carried out in Germany. In this national survey, 186 scrapie-affected sheep were found which originated from 78 flocks. The majority of these cases were of the classical TSE type (115 sheep belonging to 14 outbreaks). However, 71 cases coming from 64 flocks were of the novel atypical scrapie type. According to the regulation EU 999/2001, all TSE cases in small ruminants have to be examined by strain typing methods to explore any possibility of the existence of BSE cases in the field sheep population. Here we report on a biochemical typing strategy (termed FLI-test), which includes the determination of molecular masses, antibody binding affinities and glycosylation pattern of the TSE induced abnormal prion protein. Based on this typing approach none of the analysed German classical TSE outbreaks (total number of analysed sheep: 36) displayed biochemical features indicative for a BSE infection. However, in two cases distinct but BSE-unrelated PrP(Sc) types were found, which alludes to the existence of different scrapie strains in the German sheep population.

Animals↗
PubMed2004

Prion protein allele A136 H154Q171 is associated with high susceptibility to scrapie in purebred and crossbred German Merinoland sheep.

Prion protein (PrP) genotypes were determined in eight sheep that have been tested positive for atypical scrapie from purebred or crossbred Merinoland sheep flocks in Germany and compared with the PrP genotypes of their flock mates. Two restriction fragment length polymorphism (RFLP) analyses were developed to determine all PRNP haplotypes occurring by variations at codons 136, 154 and 171. At least one copy of the A(136) H(154) Q(171) (AHQ) allele was found in all scrapie-positive sheep while the frequency of AHQ varied from over 23% to less than 3% in the whole flocks. There was a significant association between PrP genotype and a positive scrapie diagnosis over all flocks, suggesting a high scrapie susceptibility of PrP genotypes including the AHQ allele, at least in sheep of Merinoland type. These results argue that sheep with the AHQ allele are not generally less susceptible to scrapie and support the hypothesis that the influence of this allele on scrapie susceptibility may vary from flock to flock depending on genetic and/or epidemiological factors. This has to be considered when strategies for the eradication of scrapie in sheep are based on PrP genotypes.

Alleles↗
PubMed2004

Atypical scrapie cases in Germany and France are identified by discrepant reaction patterns in BSE rapid tests.

The intensified surveillance of scrapie in small ruminants in the European Union (EU) has resulted in a substantial increase of the number of diagnosed cases. Four rapid tests which have passed the EU evaluation for BSE testing of cattle are also recommended currently and used for the testing of small ruminants by the EU authorities. These tests include an indirect ELISA (cELISA), a colorimetric sandwich ELISA (sELISA I), a chemiluminescent sandwich ELISA (sELISA II), and a Western blot (WB). To this point, the majority of samples have been screened by using either sELISA I (predominantly in Germany) or WB (predominantly in France). In this study, it is shown that a number of the German and French scrapie cases show inconsistent results using rapid and confirmatory test methods. Forty-eight German sheep, 209 French sheep and 19 French goat transmissible spongiform encephalopathy (TSE) cases were tested. All cases were recognised by the sELISA I and either one of the confirmatory methods (scrapie-associated fibrils (SAF)-immunoblot or immunohistochemistry). Surprisingly, three rapid tests failed to detect a significant number of scrapie cases (29 in France and 24 in Germany). The possible reasons for these inconsistent reaction patterns of scrapie cases are discussed. Similar discrepancies have not been observed during rapid testing of cattle for BSE, the disease for which all diagnostic methods applied have been evaluated.

Animals↗
PubMed2001

Markedly increased susceptibility to natural sheep scrapie of transgenic mice expressing ovine prp.

The susceptibility of sheep to scrapie is known to involve, as a major determinant, the nature of the prion protein (PrP) allele, with the VRQ allele conferring the highest susceptibility to the disease. Transgenic mice expressing in their brains three different ovine PrP(VRQ)-encoding transgenes under an endogenous PrP-deficient genetic background were established. Nine transgenic (tgOv) lines were selected and challenged with two scrapie field isolates derived from VRQ-homozygous affected sheep. All inoculated mice developed neurological signs associated with a transmissible spongiform encephalopathy (TSE) disease and accumulated a protease-resistant form of PrP (PrPres) in their brains. The incubation duration appeared to be inversely related to the PrP steady-state level in the brain, irrespective of the transgene construct. The survival time for animals from the line expressing the highest level of PrP was reduced by at least 1 year compared to those of two groups of conventional mice. With one isolate, the duration of incubation was as short as 2 months, which is comparable to that observed for the rodent TSE models with the briefest survival times. No survival time reduction was observed upon subpassaging of either isolate, suggesting no need for adaptation of the agent to its new host. Overexpression of the transgene was found not to be required for transmission to be accelerated compared to that observed with wild-type mice. Conversely, transgenic mice overexpressing murine PrP were found to be less susceptible than tgOv lines expressing ovine PrP at physiological levels. These data argue that ovine PrP(VRQ) provided a better substrate for sheep prion replication than did mouse PrP. Altogether, these tgOv mice could be an improved model for experimental studies on natural sheep scrapie.

Animals↗
PubMed2000

Characterization of BSE and scrapie strains/isolates.

Following the BSE epidemic in cattle and the emergence of a variant form of Creutzfeldt-Jakob disease in humans, the question was raised whether BSE has been transmitted to small ruminants by the inadvertent feeding of infectious meat and bone meal. Such infections could easily be concealed in countries where scrapie is endemic. To address this issue by immuno-chemically analyzing the PrP(Sc) fragments, we have developed two lines of research. Firstly we have focused on the development of criteria for the differential characterization of experimental BSE and scrapie strains/isolates in rodents. To date, three criteria have been identified: quantification of the relative banding intensities of PrP(Sc) glycotypes using a photoimaging technique; the non-uniform kinetic of proteinase K degradation of PrP(Sc); and differences in the molecular masses of their non-glycosylated PrP(Sc) fragments after PK cleavage in immunoblot. The second line of research focused on the implementation of the criteria described above to representative samples from scrapie diseased Irish sheep. Using these three criteria, no evidence was found for the presence of a BSE infection in these animals. However, the final conclusion must take into account the results of mouse incubation time and mouse lesion profile data which are currently being generated.

Amino Acid Sequence↗
PubMed2000

Detection of cattle-derived BSE prions using transgenic mice overexpressing bovine PrP(C).

In interspecies transmissions of transmissible spongiform encephalopathies, the agent has to overcome a species barrier that is largely influenced by the rate of homology between the prion proteins (PrP(C)) of the two involved species. Generating transgenic mice expressing PrP(C) of a foreign species is an approach to develop TSE models that are at least partly devoid of a species barrier. The availability of such animals would enable the detection of low doses of infectivity in tissues or bodily fluids derived from other species. We generated transgenic mice that overexpress bovine PrP(C) (Tgbov XV mice) for the development of an improved detection assay for cattle derived BSE prions. These mice succumbed to the disease 250 days after inoculation with a brain homogenate from BSE diseased cattle. Diagnosis of BSE in transgenic mice was confirmed using Western blot, as well as histological and immunohistochemical methods. In contrast, transgenic mice overexpressing murine PrP(C) (tga20 mice) did not display shorter incubation times than nontransgenic RIII mice infected with the same inoculum. The expression of a chimaeric PrP of murine and bovine sequences rendered such mice partly, if not entirely resistant to an infection with the BSE agent.

Animals↗
PubMed1999

A novel epitope for the specific detection of exogenous prion proteins in transgenic mice and transfected murine cell lines.

Prion diseases are closely linked to the conversion of host-encoded cellular prion protein (PrPC) into its pathological isoform (PrPSc). PrP conversion experiments in scrapie infected tissue culture cells, transgenic mice, and cell-free systems usually require unique epitopes and corresponding monoclonal antibodies (MAbs) for the immunological discrimination of exogenously introduced and endogenous PrP compounds (e.g., MAb 3F4, which is directed to an epitope on hamster and human but not on murine PrP). In the current work, we characterize a novel MAb designated L42 that reacts to PrP of a variety of species, including cattle, sheep, goat, dog, human, cat, mink, rabbit, and guinea pig, but does not bind to mouse, hamster, and rat PrP. Therefore, MAb L42 may allow future in vitro conversion and transgenic studies on PrPs of the former species. The MAb L42 epitope on PrPC includes a tyrosine residue at position 144, whereas mouse, rat, and hamster PrPs incorporate tryptophane at this site. To verify this observation, we generated PrP expression vectors coding for authentic or mutated murine PrPCs (i.e., codon 144 encoding tyrosine instead of tryptophan). After transfection into neuroblastoma cells, MAb L42 did not react with immunoblotted wild-type murine PrPC, whereas L42 epitope-tagged murine PrPC was strongly recognized. Immunoblot and fluorescence-activated cell sorting data revealed that tagged PrPC was correctly posttranslationally processed and translocated to the cell surface.

Amino Acid Sequence↗
PubMed1998

Cellular prion proteins of mammalian species display an intrinsic partial proteinase K resistance.

Prion diseases are characterized by the intraneuronal accumulation of a pathological isoform (PrP(Sc)) of host-encoded prion protein (PrP(C)). While PrP(Sc) displays a partial resistance, PrP(C) is easily degraded by this enzyme. As it turned out in our experiments, PrP(C) of six species is initially degraded to an intermediate fragment of 25-28 kDa prior to complete proteolysis which was solely detected by antibodies binding to epitopes carboxy-terminally of amino acid 144 of PrP(C). The intermediate fragment thus lacked the aminoterminus of PrP(C). These findings are well in line with the putative structure of PrP(C): the amino-terminus consists of a highly flexible and thus more proteinase K sensitive tail while the carboxy-terminus is folded into possibly more resistant alpha-helices and beta-sheets. We observed significant differences in the PK sensitivities of PrP(C) from six different species and from three ovine PrP alleles, while no remarkable variation was seen in PrP(C) from six regions of an ovine brain. This indicates that variations in the sequence of PrP may alter its three-dimensional structure and consequently change its sensitivity towards proteolytic enzymes.

Animals↗
PubMed1998

Sensitivity of the Western blot detection of prion protein PrPres in natural sheep scrapie.

The sensitivity of Western blot detection of PrPres using two different extraction procedures on brain material of 30 scrapie-affected sheep was compared. Whereas PrPres could be detected in all sheep after extraction with the first method, 30% did not give any signal after extraction with the second method. However, the second method, when positive, permitted the detection of PrPres from smaller amounts of infected brain tissue. When used with the ruminant specific monoclonal antibody p4, the second method gave positive signals corresponding to less than 12.5 microg of scrapie-infected brain, that, up to now, is the highest sensitivity described for PrPres detection from naturally infected ruminant brains. The overall results showed highly variable levels of PrPres between sheep and are presented in relation to breed, survival time and animal genotype data. Further progress can thus be expected for PrPres detection in prion diseases, if more efficient extraction procedures and more sensitive immunological reagents are used. Such technical improvements could contribute to more accurate diagnosis in animals affected naturally.

Animals↗
PubMed1997

Interleukin-8 in urine: a new diagnostic parameter for intra-amniotic infection after premature rupture of the membranes.

Interleukin-8 (IL-8), a 72 amino acid peptide secreted by cells of the immune system and of the amnion, chorion and decidua, was measured in women in late pregnancy. IL-8 was detected in the urine of 91 of 104 women with premature rupture of the fetal membranes, with values exceeding 1000 ng/L in cases of severe intra-amniotic infection. Women with urinary tract infections were excluded. The routine measurement of IL-8 in urine, together with C-reactive protein in serum, thus provides a low risk and technically simple approach to the assessment of intra-amniotic infection.

Amnion↗
PubMed1975

[Problems of plastic and reconstructive surgery in the face].

For reconstruction of extensive skin defects on the face two techniques can be suggested: the sliding graft from the area of the skin adjacent to the defect (technique of the sliding graft and rotation) and the technique of distant flaps. If possible preference should be given to the first technique, as it certainly leads to better results regarding function, form and structure of the skin.

Burns, Electric↗
PubMed1975

[Surgery of hypospadias (author's transl)].

The formation of an opening on the lower side of the masculine urethra is a developmental malformation. It is never combined with incontinence of the bladder. Difficulties with micturition and erection are due to a usually stenotically misdirected external orifice of the urethra, with a shortened urethra and nonelastic chorda, a remnant of the undeveloped corpus spongiosum urethra. For surgical correction (construction of a sufficiently long urethra and adequate skin extensibility) several operations are necessary, which are discussed. The most frequent complications are fistulas and problems in the wound-healing process (in approximately 30 percent of cases).

Adolescent↗