Objective To investigate the value of permeability surface (PS) in predicting hemorrhagic transformation (HT) in acute ischernic stroke (AIS) using CT peffusion (CTP).Methods The study included 31 consecutive patients who presented symptoms suggestive of an AIS for 3-9 h. All patients underwent CT examination (noncontrast CT,CTP).HT was determined by follow-up CT images.According to presence of HT,the AIS was divided into HT group (PSHT,11 patients) and non-HT group(PSNo-HT,20 patients).PS,cerebral blood flow (CBF),cerebral blood volume (CBV) and mean transit time (MTT) on both sides of brains were measured.The relative PS(rPS),relative CBF (rCBF),relative CBV(rCBV) and relative MTT(rMTT) were obtained by calculating the ratio of the values of bilateral regions.The rPS between PSHT and PSNo-HT was compared with an exact Wilcoxon signed-rank test. The rCBF,rCBV,rMTT and the PS of the ischemic side between PSHr and PSNo-HT were compared with independent-sample t test.Meanwhile,Spearman rank correlation analysis was conducted to analyze the relationship between the CTP parameters and HT.ResultsThe PS value of ischemic side was (1.61±0.77) ml · min - 1 · 100 g-1 for the PSHT group,and the value was (0.91 ± 0.49) ml · min - 1 · 100 g- 1 for the PSNo-HT group.For the PSHT group,rPS,rCBF,rCBV,rMTT were 2.76 ±0.78,0.32 ±0.18,0.66 ±0.31,2.67 ±0.71,and for the PSNo-HT group,rPS,rCBF,rCBV,rMTT were 1.35 ±0.19,0.50±0.21,0.91 ±0.28,2.62 ± 1.31.Compared with PSNo-HT,PSHT had higher rPS and PS value,and there were significant statistical differences (U =0.000,t =3.070,P ＜0.01).But rCBF and rCBV values were lower in the PSHT group compared to the PSNo-HT group,and there were significant statistical differences (trCsF =2.343,trCBV =2.210,P ＜ 0.05).There was no significant statistical difference in rMTT between the two groups(t =0.118,P ＞ 0.05).Significant positive correlations were detected between the rPS and PS with HT(r=0.496,0.821,P ＜0.01).ConclusionsThe value of rPS is helpful in predicting HT in AIS.And it can be used as a predictor in determining clinical personalized treatment and thus reduce the incidence of adverse events.

Interferon-γ (IFN-γ), a key effector molecule in anti-tumor immune response, has been well documented to correlate with the intratumoral infiltration of immune cells. Of interest, however, a high level of IFN-γ has been reported in salivary adenoid cystic carcinoma (SACC), which is actually a type of immunologically cold cancer with few infiltrated immune cells. Investigating the functional significance of IFN-γ in SACC would help to explain such a paradoxical phenomenon. In the present study, we revealed that, compared to oral squamous cell carcinoma cells (a type of immunologically hot cancer), SACC cells were less sensitive to the growth-inhibition effect of IFN-γ. Moreover, the migration and invasion abilities of SACC cells were obviously enhanced upon IFN-γ treatment. In addition, our results revealed that exposure to IFN-γ significantly up-regulated the level of programmed death ligand 1 (PD-L1) on SACC cell-derived small extracellular vesicles (sEVs), which subsequently induced the apoptosis of CD8⁺ T cells through antagonizing PD-1. Importantly, it was also found that SACC patients with higher levels of plasma IFN-γ also had higher levels of circulating sEVs that carried PD-L1 on their surface. Our study unveils a mechanism that IFN-γ induces immunosuppression in SACC via sEV PD-L1, which would account for the scarce immune cell infiltration and insensitivity to immunotherapy.
B7-H1 Antigen/metabolism* ; CD8-Positive T-Lymphocytes/pathology* ; Carcinoma, Adenoid Cystic/pathology* ; Carcinoma, Squamous Cell/pathology* ; Cell Line, Tumor ; Humans ; Immunosuppression Therapy ; Interferon-gamma/pharmacology* ; Mouth Neoplasms/metabolism* ; Programmed Cell Death 1 Receptor/metabolism* ; Salivary Gland Neoplasms/pathology*