Highly sensitive fluorescence detection of metastatic lymph nodes of gastric cancer with photo-oxidation of protoporphyrin IX.

BACKGROUND: The establishment of a precise and rapid method to detect metastatic lymph nodes (LNs) is essential to perform less invasive surgery with reduced gastrectomy along with reduced lymph node dissection. We herein describe a novel imaging strategy to detect 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence in excised LNs specifically with reduced effects of tissue autofluorescence based on photo-oxidation of PpIX. We applied the method in a clinical setting, and evaluated its feasibility. METHODS: To reduce the unfavorable effect of autofluorescence, we focused on photo-oxidation of PpIX: Following light irradiation, PpIX changes into another substance, photo-protoporphyrin, via an oxidative process, which has a different spectral peak, at 675 nm, whereas PpIX has its spectral peak at 635 nm. Based on the unique spectral alteration, fluorescence spectral imaging before and after light irradiation and subsequent originally-developed image processing was performed. Following in vitro study, we applied this method to a total of 662 excised LNs obtained from 30 gastric cancer patients administered 5-ALA preoperatively. RESULTS: Specific visualization of PpIX was achieved in in vitro study. The method allowed highly sensitive detection of metastatic LNs, with sensitivity of 91.9% and specificity of 90.8% in the in vivo clinical trial. Receiver operating characteristic analysis indicated high diagnostic accuracy, with the area under the curve of 0.926. CONCLUSIONS: We established a highly sensitive and specific 5-ALA-induced fluorescence imaging method applicable in clinical settings. The novel method has a potential to become a useful tool for intraoperative rapid diagnosis of LN metastasis.

[Preoperative perspective versus postoperative functional assessment of surgery in chronic mitral regurgitation].

Thirty patients with chronic pure mitral regurgitation who underwent mitral valve replacement during 1981 to 1986 were evaluated for pre- and one year postoperative left ventricular function using two dimensional echogram. Indicators in their evaluation were DdI, DsI, MassI and systolic and diastolic R/Th. Postoperatively, patients (n = 7) were placed in a group of abnormal responses if even one of these indicators of left ventricular function became worse than preoperative performance, patients in this group were symptomatic and two subsequently died. The postoperative FS and mVcf data fort this group were significantly lower than the patients with normal response group (n = 23). These two groups could not be differentiated by preoperative assessments of either DdI, MassI, systolic/diastolic T/Th or normalized systolic/diastolic peak velocity. However, a combination of normalized systolic peak velocity lower than 1.70 and diastolic peak velocity lower than 2.20 of left ventricular wall motion proved to be good predictors of postoperative results.

Surgical correction of Ebstein's anomaly by tricuspid valve replacement and its late problems.

The choice between valve replacement and plasty for surgical management of Ebstein's anomaly still remains controversial. Since 1960, we have treated 16 cases of Ebstein's anomaly, and 7 of the 16 cases have undergone surgical correction. Tricuspid valve replacement (TVR) without plication of the atrialized ventricle was applied in 4 cases, and Hardy's procedure was adopted in three cases. The division of the Bundle of Kent was carried out simultaneously in 2 cases with Wolff-Parkinson-White (W-P-W) syndrome of the TVR group. All patients have survived the operation. Early and late (as long as 14 years) postoperative evaluations have demonstrated superiority of the TVR group. However, the late echocardiographic findings have revealed new problems in the TVR group, such as hypokinetic or paradoxical motion of the atrialized ventricle in two cases and hypofunction of the left as well as the right heart.