Additional file 1 of Impact of familiarity with the format of the exam on performance in the OSCE of undergraduate medical students – an interventional study

Additional file 1: Supplemental Table 1. OSCE subspecialties and main checklist items

Primary antibodies used for immunohistochemistry.

<p>Primary antibodies used for immunohistochemistry.</p

SV80 microtissue protein expression pattern.

<p>IHC slices of SV80 in monocultures after ten days (Bar in A: 100 μm); SV80 microtissue staining is only shown representatively after ten days because no difference in the staining pattern between five and ten days was detected. Microtissues were completely positive for vimentin and Ki67, whereas no E-Cadherin and α-SMA expression was observed.</p

Tumour microtissue formation.

<p>SEM pictures were taken after ten days: Monocultures of A549 and SV80 were seeded in a ratio of 2500 cells/40 μl, whereas Colo699 monocultures were cultured in form of 1250 cells/40 μl. All co-cultures were seeded in a carcinoma cell: fibroblast ratio of 1∶2/40 μl (A549 co-cultures: 2500 cancer cells +5000 fibroblasts / Colo699 co-cultures: 1250 cancer cells +2500 fibroblasts). (A/B) A549 monocultures, (C/D) A549 co-cultures; (E/F) Colo699 monocultures, (G/H) Colo699 co-cultures; (I/J) SV80 monocultures. All co-cultures displayed a more homogenous and rounder microtissue surface compared to monocultures.</p

Cytokeratin 7 expression pattern.

<p>IHC staining of A549, SV80 monocultures and A549 co-cultures after ten days (Bar in 1–3: 100 μm). Cytokeratin 7 staining could only be observed in cancer cells but not in SV80 cells.</p

Extracellular matrix expression pattern.

<p>Fibronectin was displayed in microtissues after ten days. (Bar in A549/SV80 monocultures: 50 μm, bar in all other microtissues: 100 μm); Secretion of fibronectin could be observed in microtissues containing fibroblasts, whereas in all tumour cell monocultures no fibronectin secretion could be detected.</p

Tumour microtissue architecture.

<p>Semi-thin sections (1 μm slices) of A549/Colo699 mono- and co-cultures after ten days of cultivation stained with toluidine. Bar in all pictures: 20 μm. A549 cells form rugged spheroids resembling a more multi-layered tissue and exhibit a rough surface. Colo699 monocultures reveal a spheroidal structure with a loose surface. When fibroblasts are added both cell lines build a more compact microtissue with a regular surface.</p

Growth curve and Cell proliferation/activation pattern.

<p><b>A</b>: Microtissue volumes were calculated by the formula V = 4/3*Π*r3, where r = ½*√ d1*d2. Mean volumes are displayed in μm3 with their corresponding standard deviations. <b>B</b>: Mean and standard deviation of Ki67 positivity was calculated by counting Ki67 positive and negative cell nuclei on slices of three different spheroids representatively. Thereafter, the percentage of positive cell nuclei to whole cell cumber was calculated. Co-cultivation of both tumour cell lines with a fibroblast cell line led to a significant upregulation (p<0,05) of Ki67 expression in all microtissues.</p

A549 microtissue protein expression pattern.

<p>IHC slices of A549 in mono- and co-cultures after five and ten days (Bar in A-D: 100 μm, bar in Insert: 25 μm); an increase in vimentin and a simultaneous decrease in E-Cadherin is displayed in co-cultures. Also an upregulation of Ki67 expression in co-cultures was detected.</p

Summary of IHC protein expression pattern. +/- displays the presence/absence of the indicated protein.

<p>Summary of IHC protein expression pattern. +/- displays the presence/absence of the indicated protein.</p