T.I.E. wrote:
Dead Machine wrote:
T.I.E, we can't eat human flesh, it gives us a disease that makes holes appear in your brain, and then you die.
the Minister says ? :roll:
If you eat too much over a period of time, that is. That's what caused Mad Cow disease in cows, they were eating leftovers from slaughter that weren't fit for market consumption.
Quote:
Prion Diseases
Just as nucleic acids can carry out enzymatic reactions, proteins can be genes. Reed Wickner.
This document describes infectious agents which (almost certainly) do not have a nucleic acid genome. It seems that a protein alone is the infectious agent. The infectious agent has been called a prion. A prion has been defined as "small proteinaceous infectious particles which resist inactivation by procedures that modify nucleic acids". The discovery that proteins alone can transmit an infectious disease has come as a considerable surprise to the scientific community.
Prion diseases are often called spongiform encephalopathies because of the post mortem appearance of the brain with large vacuoles in the cortex and cerebellum. Probably most mammalian species develop these diseases. Specific examples include:
* Scrapie: sheep
* TME (transmissible mink encephalopathy): mink
* CWD (chronic wasting disease): muledeer, elk
* BSE (bovine spongiform encephalopathy): cows
Humans are also susceptible to several prion diseases:
* CJD: Creutzfeld-Jacob Disease
* GSS: Gerstmann-Straussler-Scheinker syndrome
* FFI: Fatal familial Insomnia
* Kuru
* Alpers Syndrome
These original classifications were based on a clinical evaluation of a patients family history symptoms and are still widely used, however more recent and accurate molecular diagnosis of the disease is gradually taking the place of this classification.
The incidence of sporadic CJD is about 1 per million per year.
GSS occurs at about 2% of the rate of CJD.
It is estimated that 1 in 10,000 people are infected with CJD at the time of death.
These figures are likely to be underestimates since prion diseases may be misdiagnosed as other neurological disorders.
The diseases are characterised by loss of motor control, dementia, paralysis wasting and eventually death, typically following pneumonia. Fatal Familial Insomnia presents with an untreatable insomnia and dysautonomia. Details of pathogenesis are largely unknown.
Visible end results at post-mortem are non-inflammatory lesions, vacuoles, amyloid protein deposits and astrogliosis.
GSS is distinct from CJD, it occurs typically in the 4th-5th decade, characterised by cerebellar ataxia and concomitant motor problems, dementia less common and disease course lasts several years to death. (Originally thought to be familial, but now known to occur sporadically as well).
CJD typically occurs a decade later has cerebral involvement so dementia is more common and patient seldom survives a year (originally thought to be sporadic, but now known to be familial as well).
FFI pathology is characterised by severe selective atrophy of the thalamus.
Alpers syndrome is the name given to prion diseases in infants.
Scrapie was the first example of this type of disease to be noticed and has been known about for many hundreds of years. There are two possible methods of transmission in sheep:
1. Infection of pasture with placental tissue carrying the agent followed by ingestion,or direct sheep-lamb transmission i.e. an acquired infection.
2. Parry showed considerable foresight by suggesting that it is not normally an infectious disease at all but a genetic disorder. He further suggested that selective breeding would get rid of the disease.
Humans might be infected by prions in 2 ways:
1. Acquired infection (diet and following medical procedures such as surgery, growth hormone injections, corneal transplants) i.e. infectious agent implicated.
2. Apparent hereditary mendelian transmission where it is an autosomal and dominant trait. This is not prima facie consistent with an infectious agent.
This is one of the features that single out prion diseases for particular attention. They are both infectious and hereditary diseases (?see below). They are also sporadic, in the sense that there are also cases in which there is no known risk factor although it seems likely that infection was acquired in one of the two ways listed above.
Kuru is the condition which first brought prion diseases to prominence in the 1950s. Found in geographically isolated tribes in the Fore highlands of New Guinea. Established that ingesting brain tissue of dead relatives for religious reasons was likely to be the route of transmission. They ground up the brain into a pale grey soup, heated it and ate it. Clinically, the disease resembles CJD. Other tribes in the vicinity with same religious habit did not develop the disease. It is speculated that at some point in the past a tribe member developed CJD, and as brain tissue is highly infectious this allowed the disease to spread. Afflicted tribes were encouraged not to ingest brain tissue and the incidence of disease rapidly declined and is now almost unknown.
