Table 1.
Extracted parameters
| Parameter | Phenotype | Articles | |
| General article information | |||
| Conflict of interests statement | Declaration of no conflict of interests | 86 | 62.8% |
| Declaration of existing conflict of interests | 5 | 3.6% | |
| No statement about conflict of interests | 46 | 33.6% | |
| U-87 MG in vitro model | |||
| Source of U-87 MG cells | ATCC, Manassas, Virginia, USA | 66 | 48.2% |
| Chinese Academy of Sciences, Beijing, China | 27 | 19.7% | |
| Other commercial/institutional sources | 24 | 17.5% | |
| Colleagues | 11 | 8.0% | |
| Not reported | 9 | 6.6% | |
| U-87 MG cell line authentication conducted | Yes | 16 | 11.7% |
| No/not reported | 121 | 88.3% | |
| U-87 MG age (maximum number of cell passage) | 3 | 1 | 0.7% |
| 7 | 1 | 0.7% | |
| 8 | 1 | 0.7% | |
| 10 | 3 | 2.2% | |
| 15 | 4 | 2.9% | |
| 20 | 2 | 1.5% | |
| 35 | 1 | 0.7% | |
| 100 | 1 | 0.7% | |
| Not reported | 123 | 89.8% | |
| U-87 MG culture conditions | |||
| Glucose level of cell culture medium | Low glucose (1000 mg/dL) | 3 | 2.2% |
| High glucose (4500 mg/dL) | 24 | 16.8% | |
| Low and high glucose (in different experiments) | 1 | 0.7% | |
| Without glucose | 1 | 0.7% | |
| Not reported | 108 | 78.8% | |
| Mycoplasma contamination checked | Yes | 8 | 5.8% |
| Not reported | 129 | 94.2% | |
| Supplemented antibiotics | Penicillin and streptomycin | 92 | 67.2% |
| Other antibiotics | 5 | 3.6% | |
| No antibiotics supplemented | 3 | 2.2% | |
| Not reported | 37 | 27.0% | |
| Source of FBS | Thermo Fisher Scientific, Waltham, Massachusetts, USA (including Gibco, Invitrogen and Life Technologies) | 51 | 37.2% |
| Hyclone Laboratories, Logan, Utah, USA | 13 | 9.5% | |
| Sigma-Aldrich, St Louis, Missouri, USA | 8 | 5.8% | |
| Other sources | 22 | 16.1% | |
| FBS was not used | 1 | 0.7% | |
| Not reported | 42 | 30.7% | |
| Control group and outcome measurement | |||
| Type of untreated control | Drug vehicle (DMSO) | 37 | 27.0% |
| Cell culture medium only | 13 | 9.5% | |
| Not reported | 87 | 63.5% | |
| Cell viability assessment method | MTT assay, colorimetric | 67 | 48.9% |
| CCK8, colorimetric | 20 | 14.6% | |
| SRB assay, colorimetric | 9 | 6.6% | |
| Alamar Blue assay, colorimetric | 7 | 5.1% | |
| Trypan Blue Exclusion test, cell counting | 6 | 4.4% | |
| WST-1 assay, colorimetric | 6 | 4.4% | |
| MTS assay, colorimetric | 3 | 2.2% | |
| Other assessment methods | 11 | 8.0% | |
| More than one assay used | 8 | 5.8% | |
Extracted parameter phenotypes (including additional information obtained through contacting the authors). One phenotype per article. The column ‘Articles’ shows the absolute and relative frequencies of articles with the parameter phenotype in relation to all 137 included articles.
ATCC, American Type Culture Collection; CCK8, Cell Counting Kit-8; DMEM, Dulbecco’s Modified Eagle’s Medium; DMSO, dimethyl sulfoxide; FBS, fetal bovine serum; U-87 MG, Uppsala-87 Malignant Glioma; MTS, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; SRB, Sulforhodamine B; WST-1, water soluble tetrazolium 1.