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36/100

✓ Peer-reviewed alzhub usefulness score 36 out of 100. Biomarkers

Topic: Gut, metabolism and diet

Plain-language summary

Results of neuropathologic, spectroscopic, and neurochemical studies continue to confirm a major role for ammonia in the pathogenesis of the central nervous system complications of both acute and chronic liver failure. Damage to astrocytes characterized by cell swelling (acute liver failure) or Alzheimer Type II astrocytosis (chronic liver failure) can be readily reproduced by acute or chronic exposure of these cells in vitro to pathophysiologically relevant concentrations of ammonia. Furthermore, exposure of the brain or cultured astrocytes to ammonia results in similar alterations in expression of genes coding for key astrocytic proteins. Such proteins include the structural glial fibrillary acidic protein, glutamate transporters, and peripheral-type (mitochondrial) benzodiazepine receptors. Brain-blood ammonia concentration ratios (normally of the order of 2) are increased up to fourfold in liver failure and arterial blood ammonia concentrations are good predictors of cerebral herniation in patients with acute liver failure. Studies using 1H magnetic resonance spectroscopy in patients with chronic liver failure reveal a positive correlation between the severity of neuropsychiatric symptoms and brain concentrations of the brain ammonia-detoxification product glutamine. Increased intracellular glutamine may be a contributory cause of brain edema in hyperammonemia. Positron emission tomography studies using 13HN3 provide evidence of increased blood-brain ammonia transfer and brain ammonia utilization rates in patients with chronic liver failure. In addition to the use of nonabsorbable disaccharides and antibiotics to reduce gut ammonia production, new approaches to the treatment of hepatic encephalopathy by lowering of brain ammonia include the use of L-ornithine-L-aspartate and mild hypothermia.

Cite this study APA, Vancouver, BibTeX · download .bib or .ris

APA 7th

Butterworth, R. F. (2002). Pathophysiology of hepatic encephalopathy: a new look at ammonia. Metabolic brain disease. https://doi.org/10.1023/a:1021989230535

Vancouver

Butterworth RF. Pathophysiology of hepatic encephalopathy: a new look at ammonia. Metabolic brain disease. 2002. doi:10.1023/a:1021989230535. PMID: 12602499.

BibTeX

@article{butterworth2002-12602499,
  author  = {Butterworth, R. F.},
  title   = {{Pathophysiology of hepatic encephalopathy: a new look at ammonia}},
  journal = {Metabolic brain disease},
  year    = {2002},
  doi     = {10.1023/a:1021989230535},
  pmid    = {12602499},
  url     = {https://doi.org/10.1023/a:1021989230535}
}

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How to read this study

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Size: the record gives no participant count. Look for one in the original before trusting a pattern.
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 of neuropathologic, spectroscopic, and neurochemical studies continue to confirm a major role for ammonia in the pathogenesis of the central nervous system complications of both acute and chronic liver failure.
Furthermore, exposure of the brain or cultured astrocytes to ammonia results in similar alterations in expression of genes coding for key astrocytic proteins.

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Study details

Evidence strengthLow

How this study scored 36/100

Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people 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 21 of the 58 points we could judge it on, which is 36 out of 100.

Component	Points	Why
Journal tier	7 / 10	Tier 3 — peer-reviewed journal (Metabolic brain disease)
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	2002 — older than 20 years, still counted
Sample size	0 / 4	Participant count not stated — scores zero (not stated in the record — scored 0)
Effect reported	0 / 3	No effect size reported — scores zero (not stated in the record — scored 0)
Studied in people	0 / 3	Not stated whether this was studied in people — scores zero (not stated in the record — scored 0)
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 12602499)
Free to read	0 / 2	Behind a paywall — scores zero
Points	21 / 58	Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 21 of the 58 points we could judge it on is 36 out of 100.
Total	36 / 100	—

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