However, it is unknown if such treatment modulates 5-HT-induced vasospasm in vein grafts, and if so, what the underlying mechanisms are.
Methods: Male rabbits were divided into two groups: a control group and an SH-treated Lapatinib purchase group. The jugular vein was interposed in the carotid artery in reversed fashion. Isometric tension was examined using vein grafts after 4 weeks. 5-HT(10(-8)-10(-6) M)-induced contraction was obtained in each group in the absence or presence of the NO synthase inhibitor 1-N-G-nitroarginine (L-NNA). The expression of 5-HT2A and 5-HT1B receptors was examined immunohistochemically.
Results:
The 5-HT induced a concentration-dependent contractions in both groups. L-NNA did not significantly modify the 5-HT-induced contraction in the control group but enhanced it in the SH group. The 5-HT1B receptor antagonist GR55562 inhibited the 5-HT-induced contraction in the control group, while it increased the sensitivity of contraction to 5-HT in the SH-treated group in the absence (but not in the presence) Of L-NNA. positive immunoreactivities against 5-HT1B and 5-HT2A receptors were identified in endothelial and medial regions STI571 cell line of vein grafts in both groups, and the expression of 5-HT2A receptors (but not 5-HT1B receptors) was significantly less in the SH-treated group than in the control group.
Conclusion: Chronically administered SH to rabbits
upregulates the autoinhibitory mechanism by 5-HT through a release of NO from endothelium via an activation of endothelial 5-HT1B receptors, thus attenuating its own contraction in vein grafts. Furthermore, such SH treatment downregulates the expression of smooth muscle 5-HT2A receptors, thus further attenuating the 5-HT-induced contraction. These novel findings further support the clinical usefulness Maltase of SH in vein graft spasm after bypass grafting. (Vasc Surg 2009;50:617-25.)”
“OBJECTIVE: Aneurysms that arise from a small branch of the posterior inferior cerebellar artery (PICA) are very rare. All reported PICA
branch aneurysms originated from the choroidal branches or PICA communicating branches. No aneurysms of the PICA medullary branch have been reported previously.
CLINICAL PRESENTATION: A 62-year-old woman presented with a subarachnoid hemorrhage and intraventricular hemorrhage. Angiography showed a globular-shaped aneurysm arising from an aberrant branch of the anterior medullary segment of the left PICA. At the time of operation, the arterial branch was found to send some perforators into to the medulla oblongata and cervical spinal cord.
INTERVENTION: Aneurysm trapping was performed. Postoperatively, the patient had a mild transient difficulty in swallowing that may have been caused by manipulation of the vagus nerve rootlets.
CONCLUSION: Aneurysms can develop from a proximal medullary branch of the PICA and lead to subarachnoid hemorrhage and intraventricular hemorrhage.