FDA: too little, too late
Full text of FDA proposed rules -- all 253K of it.
Louping ill update
Faulty protein linked to ALS

FDA: too little, too late

AP 6 Jan 97 and Jan 2 Wall Street Journal

Washington -- The government is preparing to ban slaughtered animal parts in livestock feed because of links to mad ocw disease -- an effort to ensure that cattle epidemics like the one that hit Britain never happen here. Arguing that the nation would be at risk if even one US cow were somehow sickened and then used in feed, the FDA proposed the ban Thursday. [This has likely been happening for decades already -- webmaster]

"if we don't take preventive action today, we may regret it three to four years down the road," explained FDA Commissioner David Kessler. " By saying that cattle and sheep cannot get fed any product that cause this disease, we are in essence erecting a fire wall that will reduce whatever risk humans have even further." [Kessler has announced his resignation effective in January. This may be one of his last acts as commissioner.]

Puttihng therse ruminant products in animal feed not only recycled otehrwise unueable parts of slaughtered animals, it added protein. but last year, the livestock industryannounced it would voluntarily ban sheep and certain other parts from US animal feed.

The FDA's proposed ban goes further, ensuring no cow or sheep would eat feed mad with proteins from cows, sheep, goats, deer, elk, or mink -- species known to be vulnerable to these fatal diseases that literally eat spongy holes in their brains. The ban does not effect pet food or chicken or hog feed. The FDA also will continue to allow cows' blood, gelatin, and milk as feed ingredients [even though there is evidence that thse products might still carry infectious agent -- webmaster]. The ban reportedly would also cover protein from "four-D" animals--those that are dead, dying, diseased or disabled upon arrival at the rendering plant.

The cost to the rendering industry was estimated at $21 to $48 millilon dollars a year. Don Franco, of the National Renderers Association questioned whether the ban was necessary in view of lower US sheep stocks and higher rendering temperatures for longer times. Apparently, this proposal is less than what was requested by the American Feed Industry Association, which is afraid that such a narrow ban is unenforceable. Others worry include the disposal of the waste products (millions of tons of animals in already crowded landfills). The proposal will apparently not include incineration of these products. Still others worry about public perceptions, and estimate that lost sales and disposal costs could reach $1.6 billion.

The public may comment of the FDA's proposed ban for 45 days. Then, the FDA expects to finalize the regulation with months. The full text of the proposed rule on "Substances Prohibited From Use in Animal Food or Feed; Animal Proteins Prohibited in Ruminant Feed" can be accessed at the Federal Register Online via GPO Access. At Search Terms type (with quotes) "page 552" and click on the Submit button. Then choose "Substances Prohibited...." from the next page.

DATES: Written comments by February 18, 1997. FDA proposes that any final rule that may issue based on this proposal become effective 60 days after the date of its publication in the Federal Register. Submit written comments on the collection of information requirements by February 18, 1997.

ADDRESSES: Submit written comments to the Dockets Management Branch (HFA-305), Food and Drug Administration, 12420 Parklawn Dr., rm. 1-23, Rockville, MD 20857. Submit written comments on the information collection requirements to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB), New Executive Office Bldg., 725 17th St. NW., rm. 10235, Washington, DC 20503, ATTN: Desk Officer for FDA.

Louping ill in sheep/cow/people

In the 1930's: 18,000 UK sheep were inoculated against louping ill, a brain inflammatory illness spread by ticks. Despite formalin-treatment of the inoculated agent, the procedure gave rise to 1,500 cases of scrapie. Louping is a Scottish word for fleeing or leaping, related to loping. In humans, louping ill is called Russian spring-summer encephalitis, a meningo-encephalitis with muscular tremors and spasms followed by varying degrees of paralysis.

One supposes brains of sheep harboring scrapie but exhibiting only louping ill were homogenized, treated with formaldehyde, and injected intra-muscularly into sheep. The sheep became immune to louping ill as expected but contracted scrapie, which was not inactivated, as a side effect. A similar scenario has been put forward for polio vaccine and the origin of AIDS>

There are some intriguing parallels to prion disease, such as failure of the louping envelope protein to stimulate protective immunity, protein glycosylation, infectious focus in UK, and the association with scrapie. Here is what has become of louping illness (the best of Medline):

1) Sequencing and antigenic studies of a Norwegian virus isolated from encephalomyelitic sheep confirm the existence of louping ill virus outside Great Britain and Ireland. J Gen Virol 74 ( Pt 1): 109-14 (1993)

2) Nucleotide sequence of the envelope glycoprotein of Negishi virus shows very close homology to louping ill virus. Virology 190: 515-21 (1992)

3) Genomic sequence of the structural proteins of louping ill virus: comparative analysis with tick-borne encephalitis virus. Virology 180: 411-5 (1991)

4) Louping ill virus envelope protein expressed by recombinant baculovirus and vaccinia virus fails to stimulate protective immunity. Virus Res 26: 213-29 (1992)

5) The virus causing encephalomyelitis in sheep in Spain: a new member of the tick-borne encephalitis group. Res Vet Sci 58: 11-3 (1995)

6) Tick-borne flavivirus NS1 gene: identification of conserved peptides and antigenic analysis of recombinant louping ill virus NS1 protein. Virus Res 31: 245-54 (1994)

7) Studies on the glycosylation of flavivirus E proteins and the role of carbohydrate in antigenic structure. Virology 159: 237-43 (1987)

Faulty Protein Linked to ALS

Gretchen Vogel
Science Volume 274, Number 5293, pg 1612

WASHINGTON, D.C.--Neuroscientists gathered here late last month for their largest annual meeting ever. The presentations covered a wide range of topics, from spinal cord injury and obesity (Science, 29 November, p. 1466) to learning and neurodegenerative disease.

When scientists found the gene at fault in some cases of the neurodegenerative disease amyotrophic lateral sclerosis a few years ago, the discovery was the first real clue to what might cause ALS. But mutations in the gene, which makes an enzyme called superoxide dismutase (SOD1), account for only about 1% of all cases of ALS--also known as Lou Gehrig's disease--which causes a gradual paralysis and usually results in death. And it is still unclear whether SOD1 defects contribute to unexplained "sporadic" cases, which are not inherited and which constitute 95% of all cases. Now a team led by Johns Hopkins University neurologist Jeffrey Rothstein has uncovered an abnormality that seems to be widespread in patients with sporadic ALS.

In a poster session here, Rothstein and his colleagues presented evidence that a brain protein called EAAT2 is improperly made in almost half of the patients they studied. If confirmed, Rothstein says, the finding would strengthen earlier suspicions that a deficiency of the protein, which deactivates and recycles the neurotransmitter glutamate, is a "potential cause or contributor" to the disease, because such a deficiency could lead to a glutamate buildup. Glutamate is toxic to cells in high concentrations, and some researchers have theorized that the paralysis of ALS might be caused by increased levels of the neurotransmitter and the resulting death of neurons that control the muscles.

... Rothstein, postdoctoral researcher Glen Lin, and research associate Lynn Bristol discovered the EAAT2 defects while following up on earlier observations that many ALS patients have abnormally low levels of the protein in areas affected by the disease: the motor cortex and spinal cord. To track down the cause of that deficit, the Hopkins team examined the messenger RNAs (mRNAs), which provide the direct instructions for making the protein, in brain and spinal cord tissue obtained at autopsy from ALS patients. They found that those mRNAs were often edited incorrectly in precisely the same tissues where the low protein levels were seen.

Most genes of higher organisms contain non-protein-coding sequences, called introns, that have to be removed from the mRNAs before the proteins themselves are synthesized. But the Hopkins workers found that the machinery that removes the introns from the EAAT2 mRNAs made mistakes in 11 of the 20 sporadic ALS patients they tested. It either failed to remove an unneeded intron, or it deleted an essential protein-coding sequence, called an exon. As a result, the mRNAs make no EAAT2 at all or make a faulty version. Rothstein and his colleagues did not find the abnormalities in brain tissue from 12 normal subjects or in 16 patients who died of other neurodegenerative diseases, including Alzheimer's and Huntington's. This suggests that the EAAT2 defect is specific to ALS and not just a general consequence of nerve cell death.

Many questions remain unanswered. The researchers do not yet know what causes the mistakes in the mRNAs. It may be that a mutation in the EAAT2 gene gives the cell's RNA-processing machinery the wrong directions for removing the introns. Or the fault may lie in the processing machinery itself. Also unexplained, Rothstein says, is how the defect could be restricted to the motor cortex and spinal cord.