Yoshikazu Yano

Adventitial Mast Cells Contribute to Pathogenesis in the Progression of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is histologically characterized by medial degeneration and various degrees of chronic adventitial inflammation, although the mechanisms for progression of aneurysm are poorly understood. In the present study, we carried out histological study of AAA tissues of patients, and interventional animal and cell culture experiments to investigate a role of mast cells in the pathogenesis of AAA. The number of mast cells was found to increase in the outer media or adventitia of human AAA, showing a positive correlation between the cell number and the AAA diameter. Aneurysmal dilatation of the aorta was seen in the control (+/+) rats following periaortic application of calcium chloride (CaCl2) treatment but not in the mast cell–deficient mutant Ws/Ws rats. The AAA formation was accompanied by accumulation of mast cells, T lymphocytes and by activated matrix metalloproteinase 9, reduced elastin levels and augmented angiogenesis in the aortic tissue, but these changes were much less in the Ws/Ws rats than in the controls. Similarly, mast cells were accumulated and activated at the adventitia of aneurysmal aorta in the apolipoprotein E–deficient mice. The pharmacological intervention with the tranilast, an inhibitor of mast cell degranulation, attenuated AAA development in these rodent models. In the cell culture experiment, a mast cell directly augmented matrix metalloproteinase 9 activity produced by the monocyte/macrophage. Collectively, these data suggest that adventitial mast cells play a critical role in the progression of AAA.

Microchimeric cells from the peripheral blood associated with cardiac grafts are bone marrow derived, long-lived and maintain acquired tolerance to minor histocompatibility antigen H-Y.

Background. Although it has been well established that themicrochimerism occurs in the peripheral blood of the recipients after varioussettings in both clinical and experimental organ transplantation,nevertheless, their roles in inducing and maintaining acquired transplantationtolerance are controversial. Furthermore, regarding the cell lineages,kinetics, and functions of the cells that constitute the microchimerism afterorgan transplantation, solid information is notavailable. Methods. Using rat heterotopic heart isografts from bone marrowchimeras between cross-sex and applying polymerase chain reaction withspecific primers to rat sex determining region of Y chromosome, a relationshipbetween a state of microchimerism and induction as well as maintenance ofacquired tolerance to H-Y antigen wereexamined. Results. Microchimeric cells of the peripheral blood (MCPB) aftercardiac grafting contain bone marrow-derived and radiation-sensitive cells.Furthermore, removal of the primary cardiac grafts revealed that microchimericcells in the peripheral blood are long-lived cells, i.e., more than 6 months.When the female rats that had contained long-lasting MCPB, were innoculatedwith syngeneic male dendritic cells, failure to sensitize female toward malespecific antigen H-Y was found tooccur. Conclusions. Thus it was suggested that radiation-sensitive, bone marrowderived, long-lived MCPB play a significant role in maintaining acquiredtransplantation tolerance to minor histocompatibility antigenH-Y.

Surgical resection of right atrial neurilemoma extending to pulmonary vein.

An asymptomatic cardiac neurilemoma was found in a 33-year-old woman. The tumor was on the anterior surface of the right atrium extending to the right upper pulmonary vein across the interatrial groove. The tumor was resected completely and right atrium, interatrial septum, left atrium and right superior pulmonary vein were reconstructed with cardiopulmonary bypass. The patient recovered uneventfully and had no recurrence 1 year after the operation. We reviewed ten reported cases of cardiac neurilemoma, including our patient.

Open surgery or stent repair for descending aortic diseases: Results and risk factor analysis

Objectives. Less invasive stent graft (SG) repair was compared with open surgery for patients with descending thoracic aortic diseases. Design. Thirty six patients undergoing SG repair (SG group) were matched for age, sex, location and pathology of aortic disease with a 36-patient surgical cohort (OS group), and retrospective matched case-control study was performed with respect to outcomes and risk factors for adverse outcomes. Results. Mortality rate was 5.6% in OS group and none in SG group (p=0.4930), and there was no significant difference in stroke and paraplegia rates between two groups. A higher prevalence of secondary procedures due to endoleak was seen in the patients of SG group (p=0.0113). Perioperative hypotension was an independent risk factor for in-hospital mortality (p=0.0071, odds ratio=34) and preoperative renal dysfunction was independent risk factor for paraplegia (p=0.0076, odds ratio=17.6). Conclusions. Although the importance of patient selection is emphasized to prevent endoleak, mortality rate was low in patients who underwent SG repair. SG repair is a promising alternative technique to open surgery for thoracic aortic diseases.

Predictor of neurologic dysfunction after elective thoracic aorta repair using selective cerebral perfusion.

Objectives This study was undertaken to determine the factors that influence postoperative neurological dysfunction after selective cerebral perfusion (SCP). Design From 1995 to August 2004, 60 patients were evaluated for the presence of cerebro-vascular disease (CVD), and then underwent thoracic aortic operations using SCP. Perioperative factors were evaluated by multivariate analyses. Results Hospital mortality rate was zero. Sixteen patients (26.7%) proved to have CVD. Permanent neurological dysfunction (PND) appeared in three patients (5.0%) and transient neurological dysfunction (TND) in two (3.3%). Univariate analysis revealed superficial temporal artery (STA) pressure during SCP (p=0.0410) to be a significant risk factor for PND. Variables that achieved values of p<0.2 (aortic cross-clamp time, presence of CVD, old cerebral infarction, presence of clots or atheroma) were examined with multivariate analysis and the presence of CVD (p=0.038) and STA pressure during SCP (p=0.032) were independent risk factors for PND. Multivariate analysis for TND did not show any risk factor. Conclusions The presence of CVD was indicated as an independent risk factor for PND after thoracic aortic operations using SCP.

Study in three different types of cardiopulmonary bypass on arterial ketone body ratio: its prognostic implication and participation of body temperature.

The aim of this study was to investigate the change of hepatic metabolic activity presented by the ketone body ratio (AKBR) during and after cardiopulmonary bypass (CPB) and to evaluate the prognostic value. AKBR were measured in 20 cases of coronary aortic bypass grafting using moderate hypothermic CPB (group M), ten cases of aortic arch surgery using deep hypothermia with selective cerebral perfusion (DHSCP) with an open technique (group D) and 15 cases of descending thoracic aortic replacement using partial CPB (group N). AKBR decreased significantly in all groups 5 min after CPB compared with the value before CPB. There was a significant difference in AKBR 1 h after CPB among the three groups and AKBR returned to the prebypass value in group N (group M, 0.32 +/- 0.16; group D, 0.14 +/- 0.04; group N, 0.48 +/- 0.14; P < 0.0001). AKBR rose significantly after the discontinuation of CPB compared with the value during CPB and returned to the prebypass value in groups M and D. The patients who underwent DHSCP with an open technique had a value of AKBR below 0.2, but liver function still recovered normally. The value of AKBR correlated with temperature significantly and a very low level of AKBR below 0.2 was observed during core cooling to 20 degrees C without negative prognostic implications. AKBR decreased 5 min after CPB in group N which suggested decreased hepatic perfusion at an early stage of partial CPB. The prognostic implication of AKBR during CPB is whether low level AKBR recovers or not.

Clinical Evaluation of SJM Prosthetic Aortic Valve by Doppler Echocardiography: Application of Energy Loss Index (ELI) as a New Index of Aortic Prosthetic Valve Function

従来,人工弁機能の指標として圧較差(PG)と有効弁口面積(EOA)などが使用されてきたが,これらはエネルギー損失や仕事量の増加を正確には示していない.今回,SJM弁による大動脈弁置換術施行40例(19HP6例,21mm16例,23mm14例,25mm4例)を対象に,これらの指標とGarciaらが提唱したエネルギー損失指数(ELI)のを超音波検査にて測定し,弁機能を検討した.手術から今回の検討までの期間は平均6.2±4.6年であった.術前後の比較では左室心筋重量,SV1+RV5,左室後壁厚が有意に減少したが,これらの減少率は人工弁のサイズによる差を認めず,左室に対する負荷の減少程度は同じであった.左室流出路径(19HP:18±2mm,21mm:21±2mm,23mm:23±4mm,25mm:27±3mm,p<0.01),体表面積(19HP:1.5±0.2m2,21mm:1.5±0.2m2,23mm:1.7±0.1m2,25mm:1.8±0.1m2,.p<0.01),EOA(19HP:1.2±0.4cm2,21mm:1.9±0.7cm2,23mm:2.2±0.9cm2,25mm:3.5±1.1cm2,p<0.01)に人工弁のサイズによる有意差を認めたが,ELI(19HP:1.01±0.41cm2/m2,21mm:1.87±1.03cm2/m2,23mm:1.83±1.09cm2/m2,25mm:3.08±1.21cm2/m2,p=0.055)には差を認めなかった.小口径人工弁は有意に左室流出路径や体表面積が小さい症例に用いられ,EOAは小さいが有効な左室肥大や心筋重量の減少を認めた.適切な症例の選択を行えば小口径人工弁による大動脈弁置換でも良好な弁機能であり,エネルギー損失も少なかった.ELIは人工弁の機能評価に有効であると思われた.

Surgical management of ductus arteriosus aneurysm in adults

Aneurysm of the ductus arteriosus is rare, especially in adults, and preoperative diagnosis is very difficult, requiring intraoperative diagnosis. A 71-year-old man was preoperatively diagnosed with ductus arteriosus aneurysm by computed tomographic scanning, magnetic resonance imaging, and aortography, which demonstrated a saccular aneurysm of the distal aortic arch. Under partial extracorporeal circulation, the aneurysm was replaced by an artificial vascular graft. The location and morphology of the aneurysm confirmed the preoperative diagnosis. The postoperative course was uneventful. Surgery for this condition is safe and is recommended the same as for common thoracic aortic aneurysm.