Chung Yg

Risk of Stroke with Temporary Arterial Occlusion in Patients Undergoing Craniotomy for Cerebral Aneurysm

OBJECTIVEnThis study was performed to elucidate the technical and patient-specific risk factors for postoperative ischemia in patients undergoing temporary arterial occlusion (TAO) during the surgical repair of their aneurysms.nnnMETHODSnEighty-nine consecutive patients in whom TAO was performed during surgical repair of an aneurysm were retrospectively analyzed. The demographics of the patients were analyzed with respect to age, Hunt and Hess grade on admission, Fisher grade of hemorrhage, aneurysm characteristics, timing of surgery, duration of temporary occlusion, and number of temporary occlusive episodes. Outcome was analyzed at the 3-month follow-up, along with the occurrence of symptomatic and radiological stroke.nnnRESULTSnIn overall, twenty-seven patients (29.3%) had radiologic ischemia attributable to TAO and fifteen patients (16.3%) had symptomatic ischemia attributable to TAO. Older age and poor clinical grade were associated with poor clinical outcome. There was a significantly higher rate of symptomatic ischemia in patients who underwent early surgery (p = 0.007). The incidence of ischemia was significantly higher in patients with TAO longer than 10 minutes (p = 0.01). In addition, patients who underwent repeated TAO, which allowed reperfusion, had a lower incidence of ischemia than those who underwent single TAO lasting for more than 10 minutes (p = 0.011).nnnCONCLUSIONnDuration of occlusion is the only variable that needs to be considered when assessing the risk of postoperative ischemic complication in patients who undergo temporary vascular occlusion. Attention must be paid to the patients age, grade of hemorrhage, and the timing of surgery. In addition, patients undergoing dissection when brief periods of temporary occlusion are performed may benefit more from intermittent reperfusion than continuous clip application. With careful planning, the use of TAO is a safe technique when used for periods of less than 10 minutes.

Analysis of multiple factors affecting surgical outcomes of proximal middle cerebral artery aneurysms.

OBJECTIVEnWe analyzed multiple factors including anatomical characteristics that influence the surgical outcomes of proximal middle cerebral artery (M1) aneurysms.nnnMETHODSnBetween January 1999 and February 2007, 189 patients had middle cerebral artery aneurysms and 60 had M1 aneurysms. Eleven patients were excluded from this study. The aneurysms were classified into two groups (superior- and inferior-wall type). Retrospectively, we evaluated characteristics of these patients and investigated factors affecting surgical outcomes.nnnRESULTSnOf the 49 patients, 28 had ruptured aneurysms and 43 had aneurysms sized less than 10mm in diameter. There were no giant aneurysms, the incidence of multiple aneurysms was high (22 patients, 45%), and intracerebral hematomas (ICH) were recognized in 13 patients (27%). The superior-wall group included 29 patients (59.2%) and the inferior-wall group had 20 (40.8%). Overall mortality and morbidity rates were 6.1% and 24.5%, respectively. Thirty-four patients (69%) showed good outcomes (GOS 4-5). Eleven and five patients showed unfavorable outcomes from the superior- and inferior-wall group, respectively. Of the four operation-related morbidity patients, three were from the superior-wall and one from the inferior-wall group. There were no statistically significant differences with respect to clinical outcome between the superior- and inferior-wall groups. Patients with poor Hunt-Hess (H-H) grades on admission showed worse outcomes than those with good H-H grades (p=0.002) and those patients without ICH revealed better outcomes than those with ICH (p=0.004).nnnCONCLUSIONSnIn patients with M1 aneurysms, clinical status on admission and the presence of ICH were significant factors for surgical outcome. Surgical morbidity seems to be related to the direction of the aneurysm. It is critical to save the lenticulostriate arteries and their branches in patients with superior-wall type aneurysms. Thorough preoperative angiographic evaluation, careful brain retraction, and meticulous inspection for hidden small branches are crucial to successful outcomes.

Role of vincristine in the inhibition of angiogenesis in glioblastoma

Objective: Vincristine, a microtubule-destabilizing drug, was found to exhibit anti-angiogenic effects and anti-tumoral activity. However, the precise mechanism by which vincristine inhibits angiogenesis in glioblastomas is not well understood. Our aim was to investigate whether vincristine affects vascular endothelial growth factor (VEGF) expression in glioblastoma cells and determine whether it is mediated by the downregulation of hypoxia-inducible factor-1α (HIF-1α). Methods: We investigated the expression of HIF-1α in glioblastoma tissues resected from patients and in human glioblastoma cell lines using immunohistochemistry, Western blot analysis, and immunocytochemistry. In addition to an MTT assay assessing the effect of vincristine on cell proliferation and viability, the effects of vincristine on VEGF mRNA expression and HIF-1α protein were examined using real-time RT-PCR and Western blot analysis under 1% O2 (hypoxia). Results: HIF-1α was expressed in the majority of glioblastoma tissues and was detected mainly in the nucleus. Strong immunoreactivity for HIF- 1 α was found often in the hypercellular zones. Under hypoxic conditions, HIF-1α protein levels in the glioblastoma cell lines increased, primarily localizing into the nucleus similar to glioblastoma tissues. Exposure of glioblastoma cells to vincristine resulted in enrichment of the G2-M fraction of the cell cycle, which suggests that vincristine-mediated growth inhibition of glioblastoma is correlated with mitotic inhibition. Using doses lower than those found to reduce the viability and proliferation of cells by 50% (IC50), vincristine decreased both the expression of VEGF mRNA and the level of HIF-1α protein in hypoxic glioblastoma cells. In addition, following exposure to vincristine, the expression of VEGF mRNA was correlated with HIF-1α protein levels. Conclusions: Our results suggest that the mechanism by which vincristine elicits an anti-angiogenic effect in glioblastomas under hypoxic conditions might be mediated, in part, by HIF-1α inhibition.

Risk factors associated with poor outcomes in patients with brain abscesses.

Objective The purpose of this study was to describe the clinical characteristics, treatment outcomes, and prognostic factors in patients with brain abscesses treated in a single institute during a recent 10-year period. Methods Fifty-one patients with brain abscesses who underwent navigation-assisted abscess aspiration with antibiotic treatment were included in this study. Variable parameters were collected from the patients medical records and radiological data. A comparison was made between patients with favorable [Glasgow Outcome Scale (GOS) ≥4] and unfavorable (GOS <4) outcomes at discharge. Additionally, we investigated the factors influencing the duration of antibiotic administration. Results The study included 41 male and 10 female patients with a mean age of 53 years. At admission, 42 patients (82%) showed either clear or mildly disturbed consciousness (GCS ≥13) and 24 patients (47%) had predisposing factors. The offending microorganisms were identified in 25 patients (49%), and Streptococcus species were the most commonly isolated bacteria (27%). The mean duration of antibiotic administration was 42 days. At discharge, 41 patients had a favorable outcome and 10 had an unfavorable outcome including 8 deaths. The decreased level of consciousness (GCS <13) on admission was likely associated with an unfavorable outcome (p=0.052), and initial hyperglycemia (≥140 mg/dL) was an independent risk factor for prolonged antibiotic therapy (p=0.032). Conclusion We found that the level of consciousness at admission was associated with treatment outcomes in patients with brain abscesses. Furthermore, initial hyperglycemia was closely related to the long-term use of antibiotic agents.