Petrous Carotid Aneurysm Causing Pulsatile Tinnitus: Case Report and Review of the Literature

We present the case of a patient who developed pulsatile tinnitus that was found to be associated with a petrous carotid aneurysm. The aneurysm was successfully obliterated using stent-assisted coiling, after which the patient was symptom-free. Although aneurysms arising from the petrous segment of the internal carotid artery are rare, this pathology must be considered as a causative factor in patients with pulsatile tinnitus. Endovascular treatment appears to have been successful in resolving the symptoms associated with this pathology.

The Effectiveness of Additional Treatment Modalities after the Failure of Recanalization by Thrombectomy Alone in Acute Vertebrobasilar Arterial Occlusion

OBJECTIVE: Acute vertebrobasilar artery occlusion (AVBAO) is a devastating disease with a high mortality rate. One of the most important factors affecting favorable clinical outcome is early recanalization. Mechanical thrombectomy is an emerging treatment strategy for achieving a high recanalization rates. However, thrombectomy alone can be insufficient to complete recanalization, especially for acute stroke involving large artery atheromatous disease. The purpose of this study is to investigate the safety and efficacy of mechanical thrombectomy in AVBAO. METHODS: Fourteen consecutive patients with AVBAO were treated with mechanical thrombectomy. Additional multimodal treatments were intra-arterial (IA) thrombolysis, balloon angioplasty, or permanent stent placement. Recanalization by thrombectomy alone and multimodal treatments were assessed by the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcome was determined using the National Institutes of Health Stroke Scale (NIHSS) at 7 days and the modified Rankin Scale (mRS) at 3 months. RESULTS: Thrombectomy alone and multimodal treatments were performed in 10 patients (71.4%) and 4 patients (28.6%), respectively. Successful recanalization (TICI 2b-3) was achieved in 11 (78.6%). Among these 11 patients, 3 (27.3%) underwent multimodal treatment due to underlying atherosclerotic stenosis. Ten (71.4%) of the 14 showed NIHSS score improvement of >10. Overall mortality was 3 (21.4%) of 14. CONCLUSION: We suggest that mechanical thrombectomy is safe and effective for improving recanalization rates in AVBAO, with low complication rates. Also, in carefully selected patients after the failure of recanalization by thrombectomy alone, additional multimodal treatment such as IA thrombolysis, balloons, or stents can be needed to achieve successful recanalization.

Regulation of Vacuolar H+-ATPase c Gene Expression by Oxidative Stress

By using differential display, we identified one of the genes encoding the multi-subunit complex protein V-ATPase, c subunit gene (ATP6L), and showed alterations of the gene expression by oxidative stresses. Expression of the ATP6L gene in Neuro-2A cells was increased by the treatment with H2O2 and incubation in hypoxic chamber, implying that the expression of the ATP6L gene is regulated by oxidative stresses. To examine mechanisms involved in the regulation of the gene expression by oxidative stresses, the transcriptional activity of the rat ATP6L promoter was studied. Transcription initiation site was determined by primer extension analysis and DNA sequencing, and promoter of the rat ATP6L and its deletion clones were constructed in reporter assay vector. Significant changes of the promoter activities in Neuro-2A cells were observed in two regions within the proximal 1 kbp promoter, and one containing a suppressor was in -195 to -220, which contains GC box that is activated by binding of Sp1 protein. The suppression of promoter activity was lost in mutants of the GC box. We confirmed by electrophoretic mobility shift and supershift assays that Sp1 protein specifically binds to the GC box. The promoter activity was not changed by the H2O2 treatment and incubation in hypoxic chamber, however, H2O2 increased the stability of ATP6L mRNA. These data suggest that the expression of the ATP6L gene by oxidative stresses is regulated at posttranscriptional level, whereas the GC box is important in basal activities of the promoter.

Role of STAT3-Interacting Protein (STIP1) in delta12-Prostaglandin J2-Induced Cell Death

delta12-Prostaglandin J2 (delta12-PGJ2) is one of cyclopentenone prostaglandins. The delta12-PGJ2 is known to induce apoptosis of tumor cells, however, it's action mechanism is not clear. It has recently been reported that STAT3 is involved in tumorigenesis. In the present study, we investigated the role of STAT3-interacting protein (STIP1) in the cytotoxicity of delta12-PGJ2, since STIP1 was recently reported as a modulator of STAT3 activation by specifically binding to inactive (unphosphorylated) STAT3. The effect of delta12-PGJ2 was observed in stably overexpressing Neuro-2A cells transfected with full cDNA of STIP1, and cytotoxicity of delta12-PGJ2 in the transfected cells was increased, compared with the vector control cells. The cytotoxicity of delta12-PGJ2 treatment was significantly accentuated by pretreatment of the STIP1-transfected cells with protein kinase inhibitor, genistein, and less activation of STAT3 in STIP1-transfected cells was shown, compared with the vector control cells. Expression of bax was also increased in the STIP1-transfected cells. These data suggest that STIP1 inhibits cell growth via inhibition of STAT3 activation in delta12-PGJ2 treatment.