Chiral recognition in host-guest complexations between crown ether hosts (H) and amino acid ester ammonium ion guests (G+) has been evaluated by fast atom bombardment @AB) mass spectrometry (m-nitrobenzyl alcohol matrix). The method uses a 1/1 mixed (for example, GR' and Cis-&+) solution of the guest whose enantiomer is isotopically (deuterium) labeled. Chiral recognition of a given host is simply measured with a given guest from the peak intensity ratio of the two diastereomeric host-guest complex ions as I
[(H f GR)+]/I[(H -I-Gs-d,)'] 3
IR/&-d,.Both the degree and the direction of chiral recognition are characterized by the I,&-d, values in the range from 0.5 to 5.4 (IR/&-d3) for the present host-guest combination systems studied. b o n g several synthetic chird crown ethers and related natural host compounds, it has been found that host 5 possesses remarkably large guest dependence upon the chiral recognition properties: (1) toward primary amino acid ester guests 14-21, a high degree of (R)-enantiomer preference (I,& = 3.2-5.4), (2) toward phenylglycine ester guest 22, almost no enantiomer recognition (IR/ZS = l.l), and (3) toward secondary amino acid ester guest 24, a weak (S)-enantiomer preference (IR/ZS = 0.7). It is also shown that the IR/Z~ values measured with the present concentrations are reasonably correlated with the relative thermodynamic stabilities in the corresponding host-guest equilibria in solution (IR/IS I KR/KS) for three typical host-guest combination systems selected (1-22,4-16, and 5-16). Accordingly, the present FABMS/ EL (enantiomer-labeled guest) method can be proposed as a new and practically useful technique for determining chiral recognition properties in the highly structured chiral host-chiral guest complexations.
Thymic haemangiomas and innominate vein aneurysms are rare with only 7 and 19 previous cases, respectively, reported in the medical literature. The aetiology of an innominate vein aneurysm remains unclear and there is no previous report of tumour involvement. We present the case of a 27-year old male with concomitant mediastinal tumour and innominate vein aneurysm who underwent surgical treatment. The tumour intruded into the lower section of the innominate vein, thus causing aneurysmal dilation. Pathologically, the tumour was diagnosed as a thymic cavernous haemangioma involving the left innominate vein. This is the first case of a thymic haemangioma presenting with an innominate vein aneurysm, and suggests that tumours may be involved in the aetiology of innominate vein aneurysms.
Background: Endovascular aneurysm repair has gained widespread acceptance, and there has been a significant increase in the number of aneurysms treated with stent grafts. However, the endovascular technique alone is often not appropriate for anatomically complex aneurysms involving the neck branches. We used the TAG stent for thoracic aortic aneurysms (TAA), and report our initial results. The prior total arch replacement and elephant trunk procedure was performed in 3 cases with dilated ascending aorta, total debranching from ascending aorta with sternotomy in 5, and carotid-carotid artery crossover bypass in 3 cases. Meanwhile, TEVAR with coverage of the left subclavian artery was performed in the remaining 9 distal arch cases. In 3 cases with extremely short necks, a 0.018" guide wire was inserted percutaneously in a retrograde manner through the common carotid artery (CCA) into the ascending aorta to place the stent graft in close proximity to the CCA (wire protection). In 1 of these 3 cases, the TAG stent was deployed through the CCA, and the 0.018" guide wire was used to deliver a balloon-expandable stent in order to restore the patency of the CCA. In arch and distal arch aneurysm cases, perioperative mortality and the incidence of stroke were both 5.0%; dissection of the ascending aorta was seen in one case (5.0%).
Conclusion
Objective:
Ultrasound-guided thrombin injection (UGTI) is an option for the treatment of postcatheterization pseudoaneurysms. This method is less invasive and less time-consuming compared with other procedures since it can be performed without general anesthesia, skin incision, or occlusion of the artery. Herein, we report on the efficacy of UGTI for postcatheterization bleeding complications.
Methods:
Postcatheterization bleeding complications include postcatheterization pseudoaneurysm and failed hemostasis. In this study, failed hemostasis was defined as cases in which hemostasis could not be accomplished by 30 min of manual compression following sheath removal. A retrospective study of eight cases in which we performed UGTI for postcatheterization bleeding complications between July 2016 and June 2019 at our institution was performed to evaluate technical success and recurrence of pseudoaneurysm or rebleeding events.
Results:
Among these eight cases, there were three cases of pseudoaneurysm and five cases of failed hemostasis. In all cases, technical success was achieved without any complications such as distal embolism or allergic reaction. There were no recurrences of pseudoaneurysm or rebleeding events during an average follow-up of 5.25 months.
Conclusion:
We believe that UGTI is effective not only for postcatheterization pseudoaneurysms but also for failed hemostasis.
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