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    An early warning system using machine learning for the detection of intracranial hematomas in the emergency trauma setting
    (Turkish Neurosurgical Society, 2022) Aydoseli, Aydın; Ünal, Tuğrul Cem; Kardeş, Onur; Doğuç, Özge; Dolaş, İlyas; Adıyaman, Ali Ekrem; Ortahisar, Emircan; Silahtaroğlu, Gökhan; Aras, Yavuz; Sabancı, Pulat Akın; Sencer, Serra; Sencer, Altay
    AIM: To present an early warning system (EWS) that employs a supervised machine learning algorithm for the rapid detection of extra-axial hematomas (EAHs) in an emergency trauma setting. MATERIAL and METHODS: A total of 150 sets of cranial computed tomography (CT) scans were used in this study with a total of 11,025 images. Of the CTs, 75 were labeled as EAH, the remaining 75 were normal. A random forest algorithm was utilized for the detection of EAHs. The CTs were randomized into two groups: 100 samples for training of the algorithm (split evenly between EAH and normal cases), and 50 samples for testing. In the training phase, the algorithm scanned every CT slice separately for image features such as entropy, moment, and variance. If the algorithm determined an EAH on two or more images in a CT set, then the workflow produced an alert in the form of an email. RESULTS: Data from 50 patients (25 EAH and 25 controls) were used for testing the EWS. For all CTs with an EAH, an alert was produced, with a 0% false-negative rate. For 16% of the cases, the practitioner received an email from the EWS that the patient might have an EAH despite having a normal CT scan. Positive and negative predictive values were 86% and 100%, respectively. CONCLUSION: An EWS based on a machine learning algorithm is an efficient and inexpensive way of facilitating the work of emergency practitioners such as emergency physicians, neuroradiologists, and neurosurgeons.
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    Assessment of the MRI and behavioral test results in a focal cerebral ischemia-reperfusion model in the rat after separate and combined use of mouse-derived neural progenitor cells, human-derived neural progenitor cells and atorvastatin
    (Turkish Neurosurgical Society, 2018) Tahta, Alican; İzgi, Nail; Bağcı Önder, Tuğba; Erdağ, Ece; Aras, Yavuz; Genç, Çetin
    AIM: To assess the efficacy of Neural progenitor cell (NPC) transplantation in ischemic stroke, and to investigate whether atorvastatin enhances therapeutic potency of NPC after stroke. MATERIAL and METHODS: The focal cerebral ischemia-reperfusion model was performed by transient occlusion of middle cerebral artery. Rats were assigned randomly to receive intracerebral transplantation of mouse NPC alone (mNPC), human NPC alone (hNPC), mouse NPC plus oral atorvastatin (mNPC+A), human NPC plus oral atorvastatin (hNPC+A), oral atorvastatin alone, or intracerebral Dulbecco's Modified Eagle's medium injection (control group). Adhesive removal, rotarod, cylinder tests, and magnetic resonance imaging (MRI) were used for assessment of rats during 4 weeks. After sacrification on 28th day, rats were investigated by immunofluorescent staining. RESULTS: The hNPC and mNPC groups showed significantly improved functional outcome and reduced infarct area ratio compared with the control group. The hNPC group had significantly better performance and lower infarct area ratio than the mNPC group. Addition of atorvastatin to stem cell therapy significantly improved functional outcome, although it did not affect the infarct area ratio on MRI. Anti-inflammatory response in the infarct area was higher in the mNPC group. NPC transplantation significantly reduced the amount of microglia and a significant increase in the amount of astrocytes. CD8a+ T lymphocyte and granzyme B activities were not detected in any of the subjects. CONCLUSION: Both hNPC and mNPC treatments significantly improved functional outcome, and reduced infarct area ratio after stroke. Atorvastatin enhanced the therapeutic potency of NPCs, including neurological improvement.
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    Human-derived hair follicle stem cells and hydrogen sulfide on focal cerebral ischemia model: A comparative evaluation of radiologic, neurobehavioral and immunohistochemical results
    (Elsevier B.V., 2023) Genç, Çetin; Tahta, Alican; Erdağ, Ece; Dolaş, İlyas; Şahin, Selim; Karaöz, Erdal; Aras, Yavuz; Sabancı, Pulat Akın
    The present study investigated the effects of intracerebral human-derived hair follicle stem cells (HFBSCs), whether alone or in combination with hydrogen sulfide (H2S) in a rat model of focal cerebral ischemia. The rats were randomly assigned into 4 groups (n = 10): Control (phosphate buffered saline (PBS)), Group A (at 24 h post-middle cerebral artery occlusion(MCAo), stereotaxic intracerebral, 1,0 × 106, total 10 ?L HFBSCs), Group B (3–14 d post-MCAo, intraperitoneal (i.p.), 25 ?M/kg/day H2S), Group AB (HFBSCs + H2S). Cranial magnetic resonance images were recorded on postoperative 1st and 28th days. Three dimensional analysis was performed to calculate the infarct volumes. Rotarod and cylinder tests were performed after MCAo and finally all rats were euthanized by cardiac perfusion at 28 days after MCAo for immunohistochemical analysis. The reduction in infarct volumes of rats receiving HFBSC was significant. The cranial infarct volume on the postoperative 28th day was significantly higher in the group in which H2S was administered alone compared to the HFBSC alone group. All animals showed steadily improved spontaneous locomotor activity from day 7 post-MCAo on rotarod test, from day 1 on cylinder test, but showed no significant differences at all times. In all groups, the grading scores of CD34, CD5, CD11b and GFAP immunohistochemical markers did not differ significantly. In conclusion, intracerebral HFBSC treatment after 24 h of ischemic stroke may be an effective way to reduce the cranial infarct volume, whereas H2S treatment alone or in combination with HFBSC may not be sufficient for ischemic brain injury.