Comparison of folic acid uptake characteristics by human placental choriocarcinoma cells at acidic and physiological pH
Bibliographic record
Abstract
The aim of this work was to characterize the placental uptake of folic acid from the maternal circulation. Using 2 human trophoblast cell lines (BeWo and JAR), we verified that uptake of 3H-folic acid was pH-dependent, increasing significantly with decreasing extracellular pH. In BeWo cells, uptake of 3H-folic acid at pH 5.5 was (i) Na+-independent; (ii) inhibited by folic acid, 5-methyltetrahydrofolate (5-MTHF), and methotrexate (MTX); (iii) inhibited by the anion transport inhibitors 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 4-acetamido-4'-isothiocyano-2,2'-disulfonic acid stilbene (SITS); (iv) inhibited by the proton ionophore carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP); (v) not inhibited by blockers of receptor-mediated endocytosis (cytochalasin D and monensin); (vi) trans-inhibited by MTX and folic acid; and (vii) not affected by an anti-reduced folate transporter-1 (RFC) antibody. At pH 7.5, uptake of 3H-folic acid was (i) Na+-independent; (ii) inhibited by folic acid and MTX, but not by 5-MTHF; (iii) inhibited by SITS, but not by DIDS; (iv) not affected by FCCP; (v) inhibited by monensin (but not by cytochalasin D); (vi) trans-inhibited by folic acid (but not by MTX); and (vii) inhibited by an anti-RFC antibody. In conclusion, in BeWo cells, both RFC and receptor-mediated endocytosis seem to be involved in 3H-folic acid uptake at pH 7.5, whereas at pH 5.5, RFC and (or) a low pH-operating transporter distinct from RFC are involved.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".