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50/100

✓ Peer-reviewed alzhub usefulness score 50 out of 100. Brain scans and imaging

Topic: Disease mechanisms in lab and animal studies

Plain-language summary

Objective Soluble oligomers of amyloid beta (Abeta), rather than amyloid fibrils, have been proposed to initiate synaptic and cognitive dysfunction in Alzheimer's disease (AD). However, there is no direct evidence in humans that this mechanism can cause AD. Here, we report a novel amyloid precursor protein (APP) mutation that may provide evidence to address this question. Methods A Japanese pedigree showing Alzheimer's-type dementia was examined for mutations in APP, PSEN1, and PSEN2. In addition, 5,310 Japanese people, including 2,121 patients with AD, were screened for the novel APP mutation. The pathogenic effects of this mutation on Abeta production, degradation, aggregation, and synaptotoxicity were also investigated. Results We identified a novel APP mutation (E693Delta) producing variant Abeta lacking gulutamate-22 (E22Delta) in Japanese pedigrees showing Alzheimer's-type dementia and AD. Although the secretion of total Abeta was markedly reduced by this mutation, the variant Abeta was more resistant to proteolytic degradation. The mutant peptides showed the unique aggregation property of enhanced oligomerization but no fibrillization, and inhibited hippocampal long-term potentiation more potently than wild-type peptide in rats in vivo. Consistent with the nonfibrillogenic property of the variant Abeta, a very low amyloid signal was observed in the patient's brain on positron emission tomography using Pittsburgh compound-B. Interpretation The E693Delta mutation has been suggested as a cause of dementia because of enhanced formation of synaptotoxic Abeta oligomers. Our findings may provide genetic validation in humans for the emerging hypothesis that the synaptic and cognitive impairment in AD is primarily caused by soluble Abeta oligomers.

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APA 7th

Tomiyama, T., Nagata, T., Shimada, H., Teraoka, R., Fukushima, A., Kanemitsu, H., et al. (2008). A new amyloid beta variant favoring oligomerization in Alzheimer's-type dementia. Annals of neurology. https://doi.org/10.1002/ana.21321

Vancouver

Tomiyama T, Nagata T, Shimada H, Teraoka R, Fukushima A, Kanemitsu H, et al. A new amyloid beta variant favoring oligomerization in Alzheimer's-type dementia. Annals of neurology. 2008. doi:10.1002/ana.21321. PMID: 18300294.

BibTeX

@article{tomiyama2008-18300294,
  author  = {Tomiyama, T. and Nagata, T. and Shimada, H. and Teraoka, R. and Fukushima, A. and Kanemitsu, H. and Takuma, H. and Kuwano, R. and others},
  title   = {{A new amyloid beta variant favoring oligomerization in Alzheimer's-type dementia}},
  journal = {Annals of neurology},
  year    = {2008},
  doi     = {10.1002/ana.21321},
  pmid    = {18300294},
  url     = {https://doi.org/10.1002/ana.21321}
}

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How to read this study

Design: our record does not state a study design, so check the methods section of the original before weighing the result.
Size: the record lists 2,121 participants. Ask whether that is enough for the question, and who they were.
Effect: the record gives no effect size, so the summary above cannot say how large any difference was.

What the evidence grade means here

This page is graded low. alzhub.org assigns the grade automatically from keywords in the abstract, not from reading the paper. Low means the abstract matched neither pattern. It is the default label, and it does not mean the work is poor; many sound lab and imaging papers land here. It can add at most 5 of the 100 points in the study score, and it is a label about design, not a verdict on whether the findings are true.

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Key findings

Results We identified a novel APP mutation (E693Delta) producing variant Abeta lacking gulutamate-22 (E22Delta) in Japanese pedigrees showing Alzheimer's-type dementia and AD.
Our findings may provide genetic validation in humans for the emerging hypothesis that the synaptic and cognitive impairment in AD is primarily caused by soluble Abeta oligomers.

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Study details

Participants2,121
Evidence strengthLow

How this study scored 50/100

Published in a leading specialty journal. Scored zero for study design, effect reported and randomized / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multicenter collaboration, so those were left out: it earned 29 of the 58 points we could judge it on, which is 50 out of 100.

Component	Points	Why
Journal tier	9 / 10	Tier 2 — leading specialty journal (Annals of neurology)
Journal's citation record	— / 4	No journal record from OpenAlex — left out of this score
Study design	0 / 12	No study design recorded — scores zero, not guessed (not stated in the record — scored 0)
Strength of evidence	1 / 5	Rated “low” in our summary
Peer-review validation	10 / 10	Peer-reviewed. Published as an article in a named peer-reviewed journal.
How recent	1 / 5	2008 — within 20 year(s) of the newest study here
Sample size	3 / 4	2,121 participants
Effect reported	0 / 3	No effect size reported — scores zero (not stated in the record — scored 0)
Studied in people	3 / 3	Studied in people (participant count stated)
Randomized / blinded	0 / 2	No randomization or blinding stated — scores zero (not stated in the record — scored 0)
Times cited	— / 7	No citation count (not found in OpenAlex) — left out of this score
Citations per year	— / 5	No citation count or no year — left out of this score
Impact for its field and year	— / 6	No field-weighted citation impact (OpenAlex has none yet) — left out of this score
Cited by studies here	— / 6	Not yet checked against this library's citation graph — left out of this score
Still being cited	— / 4	No yearly citation counts — left out of this score
Senior author's track record	— / 4	Senior author's record not available — left out of this score
Institution's track record	— / 3	No institution listed in OpenAlex — left out of this score
Multicenter collaboration	— / 3	Institutions not listed — left out of this score
Indexed in PubMed	2 / 2	Indexed in PubMed (PMID 18300294)
Free to read	0 / 2	Behind a paywall — scores zero
Points	29 / 58	Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 29 of the 58 points we could judge it on is 50 out of 100.
Total	50 / 100	—

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