Mitsugu Ogawa

Label-free biochemical imaging of heart tissue with high-speed spontaneous Raman microscopy

Label-free imaging is desirable for elucidating morphological and biochemical changes of heart tissue in vivo. Spontaneous Raman microscopy (SRM) provides high chemical contrast without labeling, but presents disadvantage in acquiring images due to low sensitivity and consequent long imaging time. Here, we report a novel technique for label-free imaging of rat heart tissues with high-speed SRM combined with resonance Raman effect of heme proteins. We found that individual cardiomyocytes were identified with resonance Raman signal arising mainly from reduced b- and c-type cytochromes, and that cardiomyocytes and blood vessels were imaged by distinguishing cytochromes from oxy- and deoxy-hemoglobin in intact hearts, while cardiomyocytes and fibrotic tissue were imaged by distinguishing cytochromes from collagen type-I in infarct hearts with principal component analysis. These results suggest the potential of SRM as a label-free high-contrast imaging technique, providing a new approach for studying biochemical changes, based on the molecular composition, in the heart.

Intracellular dynamics of topoisomerase I inhibitor, CPT-11, by slit-scanning confocal Raman microscopy

Most molecular imaging technologies require exogenous probes and may have some influence on the intracellular dynamics of target molecules. In contrast, Raman scattering light measurement can identify biomolecules in their innate state without application of staining methods. Our aim was to analyze intracellular dynamics of topoisomerase I inhibitor, CPT-11, by using slit-scanning confocal Raman microscopy, which can take Raman images with high temporal and spatial resolution. We could acquire images of the intracellular distribution of CPT-11 and its metabolite SN-38 within several minutes without use of any exogenous tags. Change of subcellular drug localization after treatment could be assessed by Raman imaging. We also showed intracellular conversion from CPT-11 to SN-38 using Raman spectra. The study shows the feasibility of using slit-scanning confocal Raman microscopy for the non-labeling evaluation of the intracellular dynamics of CPT-11 with high temporal and spatial resolution. We conclude that Raman spectromicroscopic imaging is useful for pharmacokinetic studies of anticancer drugs in living cells.

Off-pump pericardiectomy using an ultrasonic scalpel and a heart positioner.

The surgical treatment of constrictive pericarditis often requires extensive pericardial dissection under cardiopulmonary bypass. We performed a pericardiectomy in a patient with constrictive pericarditis without cardiopulmonary bypass, with assistance of a sternal retractor and a suction heart positioner. The severely calcified pericardium, which adhered tightly to the epicardium, was dissected with an ultrasonic scalpel. The operation was completed without blood transfusion. There was no malignant arrhythmia.

Hemodiafiltration During Cardiac Surgery in Patients on Chronic Hemodialysis

Abstract  Background: We have developed a hemodiafiltration (HDF) protocol used during cardiac surgery to preserve fluid and electrolyte balance and prevent postoperative bleeding in patients on chronic hemodialysis. This retrospective study examined the operative results associated with our new protocol. Methods: The study included 33 consecutive patients on long‐term hemodialysis who underwent cardiac surgery at our hospital between January 2001 and April 2005, including off‐pump coronary artery bypass grafting (CABG) in 19 patients. Vascular access was achieved via a 12‐French double‐lumen catheter inserted into the left femoral vein under general anesthesia, and HDF begun when the operation was started. After completion of cardiopulmonary bypass or, in patients who underwent off‐pump CABG, after the distal anastomoses were completed, HDF was continued until target hematocrit between 30% and 35%, central venous pressure between 3 and 5 mmHg, and serum potassium concentration between 3.0 and 3.5 mEq/L were reached. The chest was closed after confirmation of hemostasis. Results: There was no in‐hospital death. Three patients were extubated in the operating room. There were no postoperative wound infection, mediastinitis, respiratory tract infection, or hemorrhage. The patients were discharged at a mean of 15.6 days after operation. Conclusions: These results suggest that intraoperative HDF lowers postoperative morbidity and mortality in chronic dialysis patients. Other advantages include early extubation and ambulation, and a shortened hospitalization.

Tissue imaging of myocardial infarct regions by a slit-scanning Raman microscope

Estimating the distribution of myocardial fibrosis after myocardial infarct is important for appropriate therapeutic planning. Here, we applied a Raman confocal microscope equipped with slit scanner for molecular tissue imaging of rat infarcted hearts. Raman spectra of the cytoplasm of cardiomyocytes included the resonance Raman bands at 751, 1130 and 1582 cm-1 arising mainly from reduced b- and c- type cytochromes. Raman spectra of fibrotic tissues at the borderzone of old myocardial infarct were highly consistent with that of collagen type I. Based on these findings, we successfully obtained Raman tissue images of a cardiomyocyte and surrounding collagen at the cellular level.

Does off-pump coronary artery bypass grafting beneficially affect renal function?

Background:  Off‐pump coronary artery bypass grafting (CABG) has been reported to beneficially affect renal function, but this remains to be confirmed. The purpose of the present paper was to study the effects of off‐pump CABG on renal function and analyse predictors of postoperative renal impairment in patients who received off‐pump CABG.

High-Resolution Raman Tissue Imaging of Rat Myocardial Infarction

Label-free imaging of cardiomyocytes and collagen in myocardial infarction would be helpful for cardiac surgery. Here, we applied slit-scanning confocal Raman microscopy for molecular tissue imaging of rat myocardial infarct regions. Cardiomyocytes surrounded by collagen were clearly imaged at the cellular level without staining by using our Raman tissue imaging method.

Postinfarction giant pseudoaneurysm in the inferior wall of the left ventricle.

For reprint information contact: Mitsugu Ogawa, MD Tel: 81 75 251 5752 Fax: 81 75 257 5910 Email: m-ogawa@koto.kpu-m.ac.jp Department of Cardiovascular and Thoracic Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan. A 66-year-old woman underwent emergency catheterbased revascularization of the occluded right coronary artery at a local hospital. On the following day, she had cardiac tamponade due to an oozing rupture of the left ventricle (LV) and needed a pericardiocentesis. Six months later, follow-up catheterization revealed a giant aneurysm larger than LV volume in the inferior wall of the LV (Figure 1). Figure1. Left ventriculography revealing a multilocular giant aneurysm larger than left ventricular volume (LV=left ventricle, AN=aneurysm)

Hemodiafiltration during Off-Pump Coronary Artery Bypass Grafting for a Chronic Dialysis Patient

慢性透析患者の冠動脈バイパス術(CABG)症例においては,その周術期管理のさまざまな問題により,合併症発症頻度,早期死亡率とも依然高いのが現状である.そこでわれわれは,慢性透析患者に対し,手術リスクを下げ,かつ周術期合併症を予防する目的で,off-pump CABG (OPCAB)の術中に血液濾過透析(HDF)を施行した.手術開始時よりHDFを開始し,OPCAB(LITA-#8～#10)を施行した.吻合中は,血行動態への影響を軽減するため,透析装置の血液流量を下げ,除水を中断した.吻合終了後は,ヘマトクリット30～35%,中心静脈圧3～5mmHg,血清K+濃度3.0～3.5mEq/lを目標に,開胸のまま,輸血を十分行いながらHDFを続行した.目標達成後,HDFを終了し,術野の出血がないことを十分確認したのちに閉胸を行い,手術を終了した.ICU入室後90分で抜管,翌朝より食事を開始し,術後2日目に一般病室へ転室した.術後3日目から透析室にて週3回の維持透析を再開し,合併症もなく術後11日目に退院となった.OPCABの術中にHDFを施行したことにより,早期抜管,早期離床が可能となり,術後経過がきわめて良好であった慢性透析患者の1例を経験した.