Talk:Amyloid

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IAPP[edit]

There are amyloid deposits of IAPP aggressively taking over beta-cell mass in estimated 80% of Type-two diabetes cases... Whether or not IAPP *causes* diabetes is up to debate, but, the deposits are definitely there. This is generally the case for all amyloidoses; whether or not the amyloid peptide is the causative agent is unknown. - (unsigned)

Reasonable enough emendation. I missed this explanation at first: sorry, my oversight, but a "see talk" or some similar notation in an edit summary would make it harder to overlook. - Nunh-huh 06:31, 5 Jul 2004 (UTC)

"links" change[edit]

Research shows that there is a link, whether or not it holds up to further scrutiny is (of course) still up in the air. The existence of a link, is, therefore, undisputable. Whether or not it's "real", that is, not an artifact of whatever methodologies were being used, is a different question. -Unknown

2nd paragraph[edit]

Could someone please rewrite the 2nd paragraph so that it is a little more intelligible to the non-specialist? ike9898 12:59, Aug 12, 2004 (UTC)

Amyloidosis[edit]

I would like to see an expanded discussion of what Amyloidosis (which redirects here) is! — brighterorange (talk) 18:26, 25 September 2005 (UTC)[reply]

Perhaps that should be a seperate page. Amyloid is the substance, while amyloidosis is the disease entity. That page itself should distinguish between the primary amyloidoses (AL amyloidosis, transthyretin-, ApoB-, lysozyme- or fibrinogen-related hereditary amyloid), AA amyloidosis secondary to chronic inflammatory conditions such as rheumatoid arthritis and FMF and some organ-specific amyloid. Clinical info from this page can then be merged there. Would you like to take the first step, Brighterorange? JFW | T@lk 19:12, 25 September 2005 (UTC)[reply]
I see the invitation is still open. Since amyloidosis desparately needs a page of its own, perhaps I will start one up after I finish a few of the more developed projects. InvictaHOG 21:17, 3 August 2006 (UTC)[reply]

Cross-polymerisation?[edit]

It says cross polymerisation is the mechanism of prion replication. What is cross-polymerisation and how is it known that prions replicate that way? It's not a term I've heard of. --Purple 22:36, 7 February 2006 (UTC)[reply]

OK I think I get that it's referring to molecules from one species seeding fibrils of the same protein from another species...--Purple 02:59, 11 March 2006 (UTC)[reply]
Based on the term that sounds in the ballpark, it should go in :) Tyciol 11:54, 12 October 2006 (UTC)[reply]

English please?[edit]

I think a paragraph needs to be added to explain simply the effects and causes of this disease. Recovery statistics, treatments, etc. If this information is already on the page, it is too dificult to understand. Druidan 21:49, 1 May 2006 (UTC)[reply]

The problem is that this is primarily an article about a set of proteins, not a disease. We need to work to bring about a page on amyloidosis itself. InvictaHOG 21:15, 3 August 2006 (UTC)[reply]
This makes sense, it's kind of like wanting an article for atherosclerosis on the cholesterol article. This should remain neutral to simply describing the physical properties, with a note leading to further emphasis on the disease it causes when building up extracellularly, especially in brain tissue for Alzheimers seeing as how popular that is to talk about. Tyciol 11:54, 12 October 2006 (UTC)[reply]
Amyloidosis is a fascinating disease which can more than fill its own article. Bits of both amyloid and amyloidosis will most likely end up on the other page, but separating the clinical syndrome and causes from the biochemistry seems like a natural break. It will probably improve both articles to limit the focus. Your cholesterol/atherosclerosis analogy is a good one! InvictaHOG 12:51, 12 October 2006 (UTC)[reply]

We do need a page about the disease, or at least a blurb explaining a bit of this in English. I love you, biology-people, but you crazy. [Too lazy to sign in.] -Unknown

It's still on my list. Sorry, I'll probably work on it in November! InvictaHOG 01:33, 11 October 2006 (UTC)[reply]
Bio guys sure are crazy, but hey, comes with figuring out how you're basically descended from bacteria :p Tyciol 11:54, 12 October 2006 (UTC)[reply]
Most people are crazy, in my experience. InvictaHOG 12:51, 12 October 2006 (UTC)[reply]

Removed section:[edit]

This talks about amyloidosis (and not amyloid), and does not specify what type of amyolidosis (by default AA amyloidosis is assumed, but the paragraph makes no reference). So should be stricken due to ambiguity, and (even if not) limited scope. If anywhere on wiki, it should go in the article pertaining to the particular type of amyloidosis observed in the cluster. Also some figures with the number of people in the class of "pennsylvania politicians" should be provided, along with population rates. For example, "unusual cluster of politicians with diabetes amyloid" might not be so unusual.

Unusual cluster among Pennsylvania politicians[edit]

In the mid-1980s, Pittsburgh Mayor Richard S. Caliguiri was diagnosed with amyloidosis. Within a few years, three of Pennsylvania's most prominent political leaders were also afflicted with the disorder. Caliguiri, longtime Erie Mayor Louis Tullio, and Governor Robert P. Casey were all diagnosed with the incurable and usually fatal disease. All three eventually died from it.

Maybe it's the scrapple? Amyloidosis has been linked to amyloid enhancing factor (AEF), which is found in diseased meat. And Pennsylvania Dutch cuisine is all about organ and scrap meats. Not to mention homemade preserving and canning. 70.184.72.38 17:54, 11 June 2007 (UTC)[reply]

Prion peer review[edit]

I've nominated the prion article for peer review, any comments welcome here! --Purple 02:59, 11 March 2006 (UTC)[reply]

Prions and amyloids are good together? Tyciol 11:54, 12 October 2006 (UTC)[reply]

Amyloid TYPE fibres[edit]

There seems to be a tendency amongest microbiologists to refer to all cross-beta type fibres as being amyloid. Amyloid itself was named after the pathological deposits found in humans. Would anyone mind if I stated this in the opening couple paragraphs, and then removed references to fibres such as curli which although cross beta, are not amyloid? --Simon 12:15, 18 August 2006 (UTC)[reply]

Sounds good, especially if you can add references! InvictaHOG 12:22, 18 August 2006 (UTC)[reply]
The old article used to make a distinction between "biophysicist's" defintion (just beta-sheet) and histopathological definition. I've reverted this edit, especially since the histopathological definition has come into question since Westermark observed IAPP fibrils in an intracellular context in a diabetes mouse model, suggesting that IAPP fibrils (certainly amyloid in the classical definition) start out intracellular and then move to the extracellular milieu.

Cross-beta[edit]

This is mentioned in the article as a key point to explaining what amyloids are, but despite that, it lacks an article. I've honestly no clue, but if no one's going to do it yet, perhaps we can redirect it here, with an explanation of what it is, or theories or whatever, on this page? Tyciol 11:54, 12 October 2006 (UTC)[reply]

An Image with an explanation is forthcoming (TaKometer)

pardon??[edit]

Hi. I've read this article, but I still have no idea what an Amyloid is. Can someone please explain in layman's terms? --Rebroad 23:24, 17 March 2007 (UTC)[reply]

Gotta agree, and I possess at least a rudimentary (if dated) OChem background. Perhaps a preliminary statement reading something like "potentially-harmful protein by product" or "a cellular deposit composed of proteins and manufactured as a by-product of protein processing, but otherwise similar to plaque/fatty deposits" ??? That's as close as I got after the opening 3-4 paragraphs. --Sskoog 05:27, 28 March 2007 (UTC)[reply]

An amyloid is a misfolded protein, a protein that adopts a special three-dimensional shape that it shouldn't. The long needle-like fibers of amyloid proteins are unusually stable and can't be removed by the body's normal procedures for removing badly made proteins. This causes problems for the body, although most researchers believe it is the process of forming these fibers,, rather than the fibers themselves, that are the problem. --Biophysik (talk) 07:35, 6 October 2008 (UTC)[reply]

You're excused[edit]

The problem of ambiguity in this article is alluded to in the introduction. The histopathological definition, although historically first, is itself ambiguous. Amyloid in this context is an insoluble protein deposit that displays apple green birefringence when treated with congo red dye. The problem is that this definition provides no further insight beyond a phenomenological observation, although it accurately describes what histopathologists observe in their microscopes.

The biophysical definition is more precise, but the histopathologists do not like applying this more precise definition, perhaps because it encroaches on their linguistic domain. To avoid conflict, biophysicists have come to using the term "amyloid-like", as if anyone would know what amyloid is "like" without a biophysical characterization.

A new word is needed here, but that would ruffle more feathers than simply borrowing the old word. Welcome to science. — Preceding unsigned comment added by 129.24.128.122 (talk) 00:12, 21 May 2014 (UTC)[reply]

Disambiguation[edit]

The amyloid class of fold is different from the amyloid protein (which is so called because it adopts an amyloid fold). I vote for a disambiguation link

Although this technically correct, there is little information on this page as is. I would vote to complete this page before starting another--Biophysik (talk) 07:35, 6 October 2008 (UTC)[reply]

removed the word other from the introduction since amayloidosis causes other pathologies than neurodegenerative processes, in fact tuberculosis related lung amaloidisis would spring to mind first rather than Alzheimers,

"Amyloids are insoluble fibrous protein aggregates sharing specific structural traits. Abnormal accumulation of amyloid in organs may lead to amyloidosis, and may play a role in various (other) neurodegenerative diseases." Jimmy joe joeseph (talk) 20:48, 20 October 2010 (UTC)[reply]

new section on dyes for histopath[edit]

There may be something useful here but this needs to be reworked for better sourcing, NPOV, and to remove the WP:PROMO:

A new complementary approach to histological staining comes from taking the benefits of traditional methods such as congo red and blending them with the benefits of immunohistochemistry. Chemists are now able to synthesise chemical dyes that are specific and sensitive like antibodies, but relatively small, stable and versatile like congo red. Studies in this field started over a decade ago where modifications of thiophene polymers were used to detect amyloid fibril formation.[1] Since then, the field has developed and modified thiophene molecules have been used detect clinical amyloids from systemic amyloidosis to Alzheimer's and Parkinson's.[2][3][4][5][6][7] One of the key benefits of these thiophene probes is that the fluorescence signal comes from changes in the molecule backbone giving rise to a whole range of different spectra depending on the binding conformation. This allowed researchers to use one thiophene probe to differentiate between different amyloid strains aβ and Tau associated with Alzheimers.[8] During the research and development, these probes were not available commercially however in 2015, the Swedish company Ebba Biotech AB began sale and distribution of an amyloid detection probe under the trademark Amytracker™.

References

  1. ^ Nilsson, K.P.R.; Herland, A; Hammarström, P; Inganäs, O (15 March 2005). "Conjugated polyelectrolytes: Conformation-sensitive optical probes for detection of amyloid fibril formation". Biochemistry. 44 (10): 3718–3724. doi:10.1021/bi047402u. PMID 15751948. Retrieved 18 March 2016.
  2. ^ Sjölander, Daniel; Röcken, Christoph; Westermark, Per; Westermark, Gunilla T.; Nilsson, K. Peter R.; Hammarström, Per. "Establishing the fluorescent amyloid ligand h-FTAAfor studying human tissues with systemic andlocalized amyloid". Amyloid: 1350–6129. doi:10.3109/13506129.2016.1158159. Retrieved 18 March 2016.
  3. ^ Sjölander, D; Bijzet, J.; Hazenberg, B.P.; Nilsson, K.P.R.; Hammarström, P (1 March 2015). "Sensitive and rapid assessment of amyloid by oligothiophene fluorescence in subcutaneous fat tissue". Amyloid. 22 (1): 19–25. doi:10.3109/13506129.2014.984063. PMID 25847117. Retrieved 18 March 2016.
  4. ^ Brelstaff, J; Ossola, B; Neher, J.J.; Klingstedt, T; Nilsson, K.P.R.; Goedert, M; Spillantini,, M.G.; Tolkovsky, A.M. (May 2015). "The fluorescent pentameric oligothiophene pFTAA identifies filamentous tau in live neurons cultured from adult P301S tau mice". Frontiers in Neuroscience. 9. doi:10.3389/fnins.2015.00184. Retrieved 18 March 2016.{{cite journal}}: CS1 maint: extra punctuation (link) CS1 maint: unflagged free DOI (link)
  5. ^ Klingstedt, T; Shirani, H; Mahler, J; Wegenast-Braun, B.M.; Nyström, S; Goedert, M; Jucker, M; Nilsson, K.P.R. (26 May 2015). "Distinct Spacing Between Anionic Groups: An Essential Chemical Determinant for Achieving Thiophene-Based Ligands to Distinguish β-Amyloid or Tau Polymorphic Aggregates". Chemistry - A European Journal. 21 (5): 9072–9082. doi:10.1002/chem.201500556. PMID 26013403. Retrieved 18 March 2016.
  6. ^ Sjöqvist, J; Maria, J; Simon, R.A.; Linares, M; Norman, P; Nilsson, K.P.R.; Lindgren, M. "Toward a molecular understanding of the detection of amyloid proteins with flexible conjugated oligothiophenes". 118 (42): 9820–9827. doi:10.1021/jp506797j. PMID 25247879. Retrieved 18 March 2016. {{cite journal}}: Cite journal requires |journal= (help)
  7. ^ Klingstedt, T; Shirani, H; Åslund, K.O.A.; Cairns, N.J.; Sigurdson, C.J.; Goedert, M; Nilsson, K.P.R. (29 July 2013). "The structural basis for optimal performance of oligothiophene-based fluorescent amyloid ligands: Conformational flexibility is essential for spectral assignment of a diversity of protein aggregates". Chemistry - A European Journal. 19 (31): 10179–10192. doi:10.1002/chem.201301463. PMID 23780508. Retrieved 18 March 2016.
  8. ^ Klingstedt, T; Shirani, H; Mahler, J; Wegenast-Braun, B.M.; Nyström, S; Goedert, M; Jucker, M; Nilsson, K.P.R. (26 May 2015). "Distinct Spacing Between Anionic Groups: An Essential Chemical Determinant for Achieving Thiophene-Based Ligands to Distinguish β-Amyloid or Tau Polymorphic Aggregates". Chemistry - A European Journal. 21 (5): 9072–9082. doi:10.1002/chem.201500556. PMID 26013403. Retrieved 18 March 2016.

- Jytdog (talk) 15:34, 18 March 2016 (UTC)[reply]

I think just removing last phrase (as I did) would work. Welcome to fix it further if needed. My very best wishes (talk) 18:27, 16 December 2016 (UTC)[reply]
Every one of those is a primary source, every one of those has Nilsson as an author. This is classic UNDUE PROMO (yes, note the last sentence). The WEIGHT and pile of primary sources is the problem. If there is a review discussing this, fine. It should be a review discussing dyes in general so this dye can be put in context. Please do not restore this marketing material. Thanks Jytdog (talk) 22:37, 16 December 2016 (UTC)[reply]
I disagree because: (a) the publications in peer reviewed journals qualify as RS and they are "secondary" to some degree (they involve review and discussion of other publications); (b) this is not a disputable, controversial or contentious material; (c) having one co-author in several papers is not a problem (maybe this is an important lab in this area - I do not know; one could leave only one ref); (d) this not about one specific dye, but about a class of dyes. Saying that, who cares? Certainly not me. My very best wishes (talk) 05:48, 17 December 2016 (UTC)[reply]
They are primary sources; that they are peer-reviewed is irrelevant. You seem unfamiliar with the marketing of research reagents... hm. Jytdog (talk) 12:33, 17 December 2016 (UTC)[reply]
Using peer-reviewed research articles is OK per WP:RS. I saw a lot of such refs, no one objected, and rightly so. Yes, reviews are better, but they are not absolutely required, especially for simple and non-controversial matters. Yes, providing an encyclopedic info about something (which does not involve any COI) can help to market some products. This is fine. You seem to be excessively vigilant about this. My very best wishes (talk) 14:27, 17 December 2016 (UTC)[reply]
As this is the "encyclopedia that anyone can edit" WP is subject to all kinds of advocacy of many kinds which results in articles that have obvious "advertisements" in them in places and holes in others. Content that obviously denigrates X or promotes Y is all over the place -- and by that I mean concretely content that is unsourced or badly sourced and NPOV in one way or another (weight, language, etc).
I've now looked and there is no discussion of these dyes in recent reviews about amyloidosis that are independent of the lab that originated them. Use of these dyes is not "accepted knowledge" and this is entirely UNDUE. But somebody reading this article would think that these dyes must be really important. (or, if they knew the field, they would see that this is obviously weird and doesn't reflect what the field views as important)
And again the originally proposed content makes it clear that this content advertises the dyes and the company (which was founded just in 2015, in the incubator near the university where this lab is (see here). That is not what WP is for.
Keeping content like this out of WP is one of the many reasons why every content policy says WP articles "should" be based on independent, secondary sources. Everything starts with sources Jytdog (talk) 18:46, 17 December 2016 (UTC)[reply]
OK, I trust your judgement. Let's not include it. My very best wishes (talk) 21:22, 17 December 2016 (UTC)[reply]
Thanks, and thanks for talking. Jytdog (talk) 05:36, 18 December 2016 (UTC)[reply]

Assessment comment[edit]

The comment(s) below were originally left at Talk:Amyloid/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Article is lacking a layman's definition in the introduction, sources throughout the article, and a clear description of why amyloid is important--Biophysik (talk) 01:15, 29 October 2008 (UTC)[reply]

Last edited at 01:15, 29 October 2008 (UTC). Substituted at 07:40, 29 April 2016 (UTC)

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Protective?[edit]

I am reading from the Buck Institute for Research on Aging that amyloid plaque may be a more complex phenomenon than previously thought. Based on research from the lab of [Rudolph E. Tanzi]] at Harvard, it now is thought to be produced by the brain as a protection - or protective response rather than as causing the problem, since amyloid has been shown to kill microbes and to respond to chemical crises.

Research wants to find out why the brain produces the amyloid as a response to three different toxic metabolic conditions: (1) inflammation (like oral bacteria) or spirochetes or fungi molds - or high sugar usage, which causes inflammation which activates inflammatory pathways, which includes making this amyloid, where the brain 'elaborates' this as a protectant; (2) Type II Alzheimers, a withdrawal of trophic support (a drop in estradiol, testosterone, vitamin D, nerve growth factor, brain-derived neurotrophic factor, et al.), many trophic molecules that support brain structure and the interactive synapses in the brain, where the response is to make amyloid as part of a brain-downsizing program; and (3) Type III Alzheimers, the amyloid plaque response may result from exposure to certain toxins (divalent metals, mercury, copper, iron, which amyloid binds tightly) or biotoxins, such as mycotoxins, lime-related toxins, etc..

There may be two sides to the amyloid - both protective and capable of harming (neurodegeneration). Many folks have been told that amyloid is a bad thing which gums up the brain and causes Alzheimers, but some research indicates that (a) the amyloid plaque is a protective development which may ALSO be neurodegenerative at some point. Why does the brain 'need' to make this protective response which can ALSO lead to 'collateral damage' - protecting against organisms and binding toxins, but depending upon the genetic predisposition of the individual - to make more or less anyloid, in some this may lead to 'brain downsizing' far earlier than would be biologically necessary?

Also, I'm reading that working with large datasets about very complex organisms discloses that there may be three different root causes for this development, why the patients have the Alzheimer's pathology: inflammatory, atrophic, toxic reasons for producing the amyloid. And there can be combinations of these reasons for the underlying degeneration, such as a glycotoxic insulin resistance which may also couple later with an atrophic response.

Can this be researched in order to improve the article? MaynardClark (talk) 22:14, 1 October 2017 (UTC)[reply]

It is sad that almost 5 years since this important post by Maynard Clark, this issue has not been addressed in the article. I had to open the Talk page to become better informed. JD Lambert(T|C) 00:39, 12 August 2021 (UTC)[reply]

Formation[edit]

I think this section needs a total rework. It makes repeated references to figures that are not included in the section - only the first reference to the sigmoidal growth curve is included. More importantly, the language needs to be far more precise. In distinguishing the models the writing suggests that it is describing how fibrils form, but then in the "Most modern model" it suggests that fibrils form from...pre-existing fibrils that fragment and grow larger? This explains the exponential phase, but it's presented as an alternative to the previous models which focus on the kinetics of nucleation i.e. the lag phase. The first two models present a clear difference: can a single monomer form a "nucleus" or does it have to be an oligomeric non-nucleus that then converts into a nucleus. But once nucleation has occurred, fragmentation and growth is a separate model for the exponential phase. Finally, there is a statement about nucleation to the "surface" of the fibril rather than the ends. After going through a lot of papers on my own I understand somewhat better what mechanism this section is trying to describe, but it's unintelligible and possibly incorrect. This paper seems to pretty forcefully suggest that the mechanism is as follows: monomers can bind to the surface of existing fibrils, upon which they are rapidly converted to generate oligomers, which then fragments off to form a standalone fibril. Can someone with more expertise than me clean up this section and make it reasonably intelligible for non-experts? It took me quite a bit of work to figure out what was being described. — Preceding unsigned comment added by 69.181.36.22 (talk) 01:33, 20 May 2020 (UTC)[reply]