Component
Deoxyuridine suppression assay
Independent substance, clinical endpoint or measured readout; study context is retained with each finding.
2 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
What acts on it
Serum B12 remained normal despite the abnormal marrow dU suppression pattern; three of nine surgery-only nitrous oxide recipients also had abnormal assays at 24 hours.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- experimental_model
- Prospective perioperative study in 22 patients undergoing cardiac bypass surgery.
- exposure
- Nitrous oxide/oxygen for 24 hours, during surgery only, or no nitrous oxide; marrow morphology and deoxyuridine suppression assays.
- limitations
- The assay is an indirect functional test, not a direct methionine-synthase rate measurement.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- A normal amount measured in serum did not establish normal intracellular function under this exposure.
- primary_references
- [b12-amess1978] Megaloblastic haemopoiesis in patients receiving nitrous oxide (1978). https://pubmed.ncbi.nlm.nih.gov/79709/ DOI: 10.1016/s0140-6736(78)92941-0
- tissue_or_cell_type
- Human bone marrow and serum
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1722–1732
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective perioperative study in 22 patients undergoing cardiac bypass surgery. · source_derived_draft · unverified_draft
### b12-nitrous-oxide-serum-function-discordance Serum B12 remained normal despite the abnormal marrow dU suppression pattern; three of nine surgery-only nitrous oxide recipients also had abnormal assays at 24 hours. Condition category: machinery_impairment nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A normal amount measured in serum did not establish normal intracellular function under this exposure. organism: Homo sapiens tissue_or_cell_type: Human bone marrow and serum experimental_model: Prospective perioperative study in 22 patients undergoing cardiac bypass surgery. limitations: The assay is an indirect functional test, not a direct methionine-synthase rate measurement. exposure: Nitrous oxide/oxygen for 24 hours, during surgery only, or no nitrous oxide; marrow morphology and deoxyuridine suppression assays. [b12-amess1978] Megaloblastic haemopoiesis in patients receiving nitrous oxide (1978). https://pubmed.ncbi.nlm.nih.gov/79709/ DOI: 10.1016/s0140-6736(78)92941-0
Complete structured claim and evidence
Where it participates (unsigned role)
All eight patients receiving nitrous oxide/oxygen for 24 hours had megaloblastic marrow and abnormal dU suppression; five unexposed patients had normoblastic marrow and normal assays.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- cross_nutrient
- B12-dependent folate handling connects to DNA synthesis; linked existing MTR evidence supplies the molecular context.
- experimental_model
- Prospective perioperative study in 22 patients undergoing cardiac bypass surgery.
- exposure
- Nitrous oxide/oxygen for 24 hours, during surgery only, or no nitrous oxide; marrow morphology and deoxyuridine suppression assays.
- limitations
- The clinical experiment did not directly measure intracellular cobalamin oxidation state or prove that serum B12 stores were depleted.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- The exposed marrow behaved as though a B12-linked DNA-synthesis step was impaired.
- primary_references
- [b12-amess1978] Megaloblastic haemopoiesis in patients receiving nitrous oxide (1978). https://pubmed.ncbi.nlm.nih.gov/79709/ DOI: 10.1016/s0140-6736(78)92941-0
- tissue_or_cell_type
- Human bone marrow
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1709–1720
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Prospective perioperative study in 22 patients undergoing cardiac bypass surgery. · source_derived_draft · unverified_draft
### b12-nitrous-oxide-marrow All eight patients receiving nitrous oxide/oxygen for 24 hours had megaloblastic marrow and abnormal dU suppression; five unexposed patients had normoblastic marrow and normal assays. Condition category: machinery_impairment nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The exposed marrow behaved as though a B12-linked DNA-synthesis step was impaired. organism: Homo sapiens tissue_or_cell_type: Human bone marrow experimental_model: Prospective perioperative study in 22 patients undergoing cardiac bypass surgery. limitations: The clinical experiment did not directly measure intracellular cobalamin oxidation state or prove that serum B12 stores were depleted. exposure: Nitrous oxide/oxygen for 24 hours, during surgery only, or no nitrous oxide; marrow morphology and deoxyuridine suppression assays. cross_nutrient: B12-dependent folate handling connects to DNA synthesis; linked existing MTR evidence supplies the molecular context. [b12-amess1978] Megaloblastic haemopoiesis in patients receiving nitrous oxide (1978). https://pubmed.ncbi.nlm.nih.gov/79709/ DOI: 10.1016/s0140-6736(78)92941-0
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.