Bovine spongiform encephalopathy

Prions—protein particles that lack nucleic acid— cause fatal transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease, scrapie, and bovine spongiform encephalopathy. Prion diseases involve an altered secondary-tertiary strucmre of a namrally occurring protein, PrPc. When PrPc interacts with its pathologic isoform PrPSc, its conformation is transformed from a predominantly a-helical strucmre to the P-sheet strucmre characteristic of PrPSc. 

If the source of the infechon persists, after onset, then the incidence of new cases is maintained at a level which is commensurate with the infechvity of the pathogen and the ffequeney of exposure of individuals. In this manner, if cases of the variant Creutzfeldt-Jacob disease (vCJD), first recognized in the mid-1990s, relates to human exposure to bovine spongiform encephalopathy-infected beef in the early 1980s, then... 

Western blot A method to detect protein in a given sample of tissue homogenate or extract. It uses gel electrophoresis to separate denatured proteins by mass. Some diagnostic applications for the Western blot include Lyme disease, bovine spongiform encephalopathy, and human immunodeficiency virus (HIV) (it is considered the gold standard for HIV diagnostic testing). 

In addition, the regulatory authorities are concerned about contamination with viruses and prions, such as the causative agent of bovine spongiform encephalopathy (BSE), which could be present in mammalian cell cultures. It is necessary to... 

Suggested Alternatives for Differential Diagnosis Sheep Scrapie, pregnancy toxemia, hypocalcemia, tetanus, listeriosis, tick pyemia, hypocuprosis, rabies, hydatid disease, and various plant poisons. Cattle Malignant catarrhal fever, listeriosis, pseudorabies, bovine spongiform encephalopathy, rabies, hypomagnesemia, hypocalcemia, acute lead poisoning, and certain plant poisons. 

The prion diseases are a closely related group of neuro-degenerative conditions which affect both humans and animals. They have previously been described as the subacute spongiform encephalopathies, slow virus diseases and transmissible dementias, and include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and the human prion diseases, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker disease (GSS), fatal familial insomnia (FFI) and kuru. Prion diseases are... 

Bruce, M. etal. Transmission of bovine spongiform encephalopathy and scrapie to mice Strain variation and the species barrier. Philos. Trans. R. Soc. Bond. [Biol] 343 405-411, 1994. 

AChR acetycholine receptor BSE bovine spongiform encephalopathy... 

Improving nutrition is essentially a process of encouraging people to make healthful choices that improve their well-being (Wansink, 2005). What happens, however, when we believe contamination, terrorism, or a genetic incidence threatens a part of the food supply Sometimes crises influence the recall, redesign, and communication efforts of individual companies (such as Tylenol, Perrier, Pilgrim s Pride). Others, such as the threat of mad cow disease (bovine spongiform encephalopathy, or BSE) in beef can compromise an entire industry. 

Fig. 3. Classification of human prion diseases. Sporadic the transformation from PrPc (circle) to PrPSc (square) occurs without apparent cause. Familial a point mutation ( ) is thought to facilitate the transformation. Infectious the transformation arises via PrPSc which acts as a template. The kinetic equations are defined by Eigen (1996). The infectious form includes kuru, iatrogenic CJD (iCJD), variant CJD (vCJD first reported in 1996), bovine spongiform encephalopathy (BSE first reported in 1985), and scrapie. In the nucleation-dependent model, monomeric PrPc and PrPSc are in chemical equilibrium.

The normal cellular form of prion protein (PrPc) can exist as a Cu-metalloprotein in vivo (492). This PrPc is a precursor of the pathogenic protease-resistant form PrPsc, which is thought to cause scrapie, bovine spongiform encephalopathy (BSE), and Creutzfeldt—Jakob disease. Two octa-repeats of PHGGGWGQ have been proposed as Cu(II) binding sites centered on histidine (493). They lack secondary and tertiary structure in the absence of Cu(II). Neurons may therefore have special mechanisms to regulate the distribution of copper. 

Konold T, Sivam SK, Ryan J, Gubbins S, Laven R, Howe MJ (2006) Analysis of clinical signs associated with bovine spongiform encephalopathy in casualty slaughter cattle. Vet 1171 438 144. 

In certain cases, serum (fetal bovine serum—FBS) is added to promote the growth of cells. However, the bovine spongiform encephalopathy (BSE) problem has necessitated tight control on the quality of FBS (refer to Exhibit 10.12). This increases production and downstream processing costs. For new cell lines being developed, serum-free and protein-free media are used to circumvent the possibility of virus contamination from animal sources and the variation that may arise from use of serum from animal herds. 

Bovine spongiform encephalopathy (BSE or mad cow disease) is a progressive neurological degenerative disease in cattle. It is caused by a mutated protein called a prion. BSE was first reported in the United Kingdom in 1986. Creutzfeldt-Jakob disease (CJD) is a rare disease that occurs in humans. Evidence to date indicates it is possible for humans to acquire CJD after consuming BSE-contaminated cattle products. 

With the background of the mad cow crisis in Europe, questions relating to the prion diseases have attracted intensive interest. It is now widely accepted that prion diseases, such as Creutzfeldt-Jakob disease (CJd) in humans and bovine spongiform encephalopathy (BSE) are caused by a conformational change of the prion protein (PrP) from a normally folded cellular form, PrP ", to an alternate, aggregation-prone, pathogenic scrapie form,... 

Encephalopathies have been known in animals for many years, e.g. scrapie, which occurs in sheep. Others include spongiform encephalopathy in domestic cats and, more recently, bovine spongiform encephalopathy. The latter developed in the UK in the 1980s symptoms include uncoordinated movement and frenzy (hence mad cow disease). There is some evidence that it occurred in cows after they were fed offal that was prepared from tissues of other cattle. 

Besides the direct and indirect risks associated with the consumption of agricultural products by humans in general, several risks are specific to the consumption of animal produce from modem agriculture. These have received considerable public attention in the past, i.e. antibiotic and hormone residuals, or just recently, such as Bovine Spongiform Encephalopathy (BSE). 

Scientific procedures for risk assessment include assessment of risk for human health as well as risk for the environment. A substantial part of the EU risk assessment work was in 1997 delegated to the DG SANCO, in relation to the scandal surrounding BSE (bovine spongiform encephalopathy or mad cow disease ). Risk assessment work not under DG SANCO includes pharmaceuticals, working environment, and health effects caused by lifestyle factors such as diet, smoking, and alcohol consumption (EU 2006f). 

EFSA was legally established by a European Parliament and Council Regulation adopted in 2002 following a series of food scares in the 1990s including the Bovine Spongiform Encephalopathy and dioxins scandals, which undermined consumer confidence in the safety of the food chain (EFSA 2007). 

This has been highlighted by a number of food safety issues. For example, lack of confidence that uncertainties were being adequately dealt with has been an important factor in recent public concerns about bovine spongiform encephalopathy and genetically modified crops, especially in Europe. Uncertainty was also a factor in the earlier controversy over alar in apples (e.g., Ames and Gold 1989 Groth 1989 Thayer 1989). 

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