Resolution Of Dissection Research Articles

Abstract 3472: Mesodissection of slide mounted tissue: Applications including tumor tissue enrichment, expression analysis, and FISH on tissue fragments

Abstract We previously reported the development of a mill based instrument for dissection of slide-mounted tissue sections. This instrument employs a specialized disposable mill bit that simultaneously dispenses liquid, cuts tissue from the slide surface using rotary motion, and aspirates the liquid along with the displaced tissue fragments. An accompanying software package is capable of transferring digital annotations between images of serially cut tissue sections to guide dissection and generate an electronic record of the process. Since the original report, a new instrument and software package has been developed with a computer controlled stage for automatic dissection of tissue. Here we report three applications using this mesodissection system. The first application investigated the relationship between dissection resolution and percent tumor tissue recovered. Areas of high tumor content were indicated on digital images of lung tumor samples. The areas of highest concentration were dissected at 400 micron resolution, the remaining areas of tumor dissected at 800 micron resolution, and then surrounding areas that would typically be recovered using manual macrodissection were dissected at 2 mm resolution. The percent mutant DNA, determined using the Sequenom OncoCarta panel, was greater than 60% for the 400 micron resolution dissections, about 45% for the 800 micron resolution dissections, and less than 10% for the remaining regions. The second application investigated the effect of various dissection related parameters on expression analysis, as assayed by Reverse Transcription and Quantitative PCR (RT-qPCR). These parameters included placing freshly microtomed FFPE tissue sections directly on slides vs. first floating on water, dissection of deparaffinized vs. paraffinized tissue, the use of crude lysates vs. purified RNA for the reverse transcription reactions, and manual dissection vs. mesodissection of the same areas on serial sections. RT-qPCR results were robust and equivalent for all parameters except those derived from crude lysates, which were equivalent to the no template controls. The third application investigated if mesodissected tissue fragments could be re-adhered to glass slides and used for FISH analysis. This application has the potential to automate and increase the throughput of FISH on tissue sections while reducing sample consumption. The preliminary results demonstrate that tissue fragments can produce good FISH signals, but a more detailed comparison to undissected tissue sections is ongoing. A significant concern is the loss of context of these fragments. This concern can be somewhat minimized by adjusting dissection conditions to obtain fragments larger than 1 mm in diameter and by mapping the dissected area onto the corresponding area a serial H&E stained tissue section using the mesodissection software. Citation Format: Nils Adey, Dale Emery, Derek Bosh, Robert Parry. Mesodissection of slide mounted tissue: Applications including tumor tissue enrichment, expression analysis, and FISH on tissue fragments. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3472. doi:10.1158/1538-7445.AM2014-3472

Progression of dissection due to residual dissection after intracoronary stenting for spontaneous coronary dissection at bifurcation site of LAD and diagonal artery

A 34-year old male patient visited our hospital due to severe chest pain. Initial ECG showed ST elevation at precordial leads and all cardiac enzymes were markedly elevated. Coronary angiography showed a long, longitudinal coronary dissection with dissected flap extending from the proximal LAD to the mid segment of the vessel and proximal diagonal artery. IVUS showed dissected flap and false lumen communicating with true lumen from proximal to mid-LAD. We implanted two paclitaxel-eluting stents using crushing technique at bifurcation lesion and overlapped another paclitaxel-eluting stent at proximal LAD for full coverage of dissection. Final angiography showed good distal flow. However, despite of maximal pressure of post stent ballooning, a residual dissection was noted at proximal LAD. IVUS examination also showed encircling gap that was noted between stent and vessel wall at proximal LAD stent area. Because distal flow was good and there was no ischemic symptom and sign, the patient was discharged. Six months later from index procedure, routine follow-up angiography and IVUS examination were performed and revealed more progressed previous residual coronary dissection at proximal LAD which was extended to bifurcation site. Our case showed, although intracoronary stenting might be an attractive approach by closure of the inlet and the false lumen, complete resolution of dissection by stenting is very important for long-term prognosis.

Long-term clinical outcomes of dissections after intracoronary β-radiation with rhenium-188-diethylene triamine penta-acetic acid-filled balloon system

Background Intracoronary radiation with a rhenium-188 ( 188Re)-filled balloon is safe and efficiently reduces restenosis, but there is a potential risk of a 188Re-filled balloon induced dissection. Little is known about the effect of radiation on dissection resolution and the late clinical outcome of dissection after brachytherapy. Methods After successful catheter-based treatments of de novo or restenotic lesion, 256 patients were randomly assigned to the radiation or control group. The 188Re-filled balloon system was designed to deliver 17.6 Gy in 1.0-mm tissue depth. Results Dissections were identified in 15 patients among the 138 patients of the radiation group (10.9%). Additional stents were deployed in 10 patients to cover the flow-limiting dissection. Binary restenosis rate (53.3% vs. 16.3%, p=0.001) and target vessel revascularization (TVR) rate (53.3% vs. 11.1%, p<0.001) were significantly higher in patients with the dissection at 9 months. Geographic miss (GM) was identified in 4 of the 10 patients who underwent additional stenting. Binary restenosis rate in the GM group (100%; 4 of 4 patients) was significantly higher than the non-GM group (33.3%; 2 of 6 patients, p=0.02). Long-term follow-up of the patients with dissections who had not undergone TVR ( n=7, mean follow-up duration: 640.7±387.3 days) has demonstrated persistent unhealed dissections. Conclusions Intracoronary radiation impairs the healing process after vessel injury and residual dissection after brachytherapy leads to adverse clinical outcomes, which was mainly due to GM in case of stent implantation.