Analysis of clinicopathological features and predictors of malignancy in intraductal papillary mucinous neoplasms of the pancreas.

BACKGROUND/AIMS: Intraductal papillary mucinous neoplasms (IPMNs) are increasingly recognized, but it is very difficult to evaluate accurately the malignancy of these neoplasms by modern imaging. We reviewed our experience in order to elucidate predictors of tumor malignancy, invasiveness, and outcome. METHODOLOGY: The clinicopathological features and surgical outcomes of 57 patients with IPMNs who underwent surgery in Nagoya University Hospital were analyzed. RESULTS: The histological diagnosis was adenoma in 40, borderline in 1, carcinoma in situ (CIS) in 7, and invasive carcinoma in 9 patients. Patients with invasive carcinomas had significantly shorter survival rates than patients with benign IPMNs or CIS (p < 0.0001). Multivariate analyses revealed that the main duct or the combined type was significantly predictive of malignancy, and both main duct or combined type and diabetes mellitus were associated significantly with invasive carcinoma. CONCLUSIONS: IPMNs generally grow slowly, but have a malignant potential that warrants radical surgical treatment when the tumor component invades the parenchyma. Our results suggest that the above factors should be considered in surgical management. The main duct type of IPMN or IPMN with mural nodules is potentially malignant or invasive. Therefore, radical operative management is indicated in these IPMNs.

[A case of metastatic breast cancer responding to weekly paclitaxel and high-dose toremifene administrated alternately].

A 64-year-old woman underwent muscle-preserving mastectomy for breast cancer in April 1999. She developed multiple lung metastases 3 months later. The metastases partially responded to 10 cycles of CAF (cyclophosphamide, adriamycin, 5-fluorouracil). However, her lung metastases worsened again 7 months later and CAF was not effective (progressive disease). We therefore began administration of low-dose paclitaxel (80 mg/m2/week) and high-dose toremifene (120 mg/day) alternately in April 2001. This alternative therapy brought a marked decrease in the lung metastases. After 4 cycles of this treatment, lung metastatic findings had disappeared from her chest X-ray. This alternative therapy is potentially effective against metastatic breast cancer.

Double potentials at successful catheter ablation site of left-sided retrograde accessory pathway: mitral isthmus block or conduction through coronary sinus musculature.

INTRODUCTION: We studied three patients who had orthodromic atrioventricular reentrant tachycardia (AVRT) using left lateral accessory pathway (AP), with difficulty in identifying the earliest site of retrograde atrial activation. METHODS AND RESULTS: Electrophysiological studies and radiofrequency ablation were performed in three patients with refractory AVRT (Case 1 was a 42-year-old woman, Cases 2 and 3 were a 52- and a 40-year-old man, respectively). During AVRT, a prolonged ventriculoatrial (VA) interval (100-180 ms) and nearly simultaneous excitation of both distal and proximal coronary sinus (CS) sites were observed. During both AVRT and ventricular pacing, double atrial potentials were recorded in all patients. Ablation of the mitral annular site showing double atrial potentials (with the first component being present just after the ventricular potential at the left lateral atrioventricular annulus) eliminated retrograde AP conduction. In Cases 1 and 2 the first component of the double potentials was atrial activation conducted through AP distal to mitral isthmus block and the second component was activation proximal to block that conducted turning around the left-sided pulmonary veins. In Case 3 the first component was CS musculature activation conducted through AP and the second component was left atrium activation via CS musculature. CONCLUSION: In AVRT that has a long VA interval and difficulty in identifying the earliest site of retrograde atrial activation, two different mechanisms existed (mitral isthmus block and conduction through CS musculature). Careful mapping of double atrial potentials and continuous VA activation at the left lateral mitral annulus is essential for determination of a successful ablation site.

Parameter predicting the recurrence of adhesive small bowel obstruction in patients managed with a long tube.

INTRODUCTION: Some of our patients showed a recurrence of adhesive small bowel obstruction (ASBO) with nonoperative management. The aim of this study was to evaluate the parameters predicting the recurrence of ASBO in patients managed with a long tube. METHODS: Of 234 patients with ASBO admitted from April 1998 to September 2002, a total of 91 who recovered with nonoperative management after long tube placement were enrolled in this retrospective clinical study. We divided them into two groups for follow-up: the recurrence group and the no-recurrence group. We compared baseline characteristics, the number of previous ASBO admissions, the number of abdominal operations, the interval from the onset of symptoms to long-tube insertion, the duration of long-tube placement, the type of the contrasted intestine through the long tube, the location of the long-tube tip, and the drainage volume through the long tube between the two groups. We then examined the cumulative recurrence rate. RESULTS: A significant difference was found in the number of previous ASBO admissions, the duration of long-tube placement (77 hours vs. 43 hours), the contrasted intestine through the long tube, and the location of the long-tube tip. By multivariate analysis, the duration of long-tube placement was an independent parameter predicting the recurrence of ASBO. CONCLUSIONS: These results suggest that the duration of long-tube placement might serve as a parameter for predicting recurrence of ASBO in patients managed with a long tube.

Characteristics of the pathological images of coronary artery thrombi according to the infarct-related coronary artery in acute myocardial infarction.

BACKGROUND: Unstable plaque and coronary arterial thrombi sometimes induce a no-reflow phenomenon after intervention whereby there is sufficient reperfusion. The greater susceptibility of the right coronary artery to development of large thrombi makes successful reperfusion more difficult, therefore the characteristics of the pathological images of coronary arterial thrombi according to the infarct-related coronary artery were investigated. METHODS AND RESULTS: Coronary arterial thrombi were extracted from 77 patients with acute myocardial infarction (AMI) using a thrombectomy catheter. The 36 patients had a thrombus containing atherosclerotic cells. Platelets, fibrin, and neutrophils were seen in all cases. The mean ratios of structural components of thrombi were 51.0 +/- 29.5% (mean +/- SD) of the platelet component, 19.9 +/- 25.7% of the erythrocyte component and 11.9 +/- 22.5% of atherosclerosis component. Erythrocyte-rich thrombi and mixed thrombi mainly composed of erythrocytes were seen in 14 of the 30 cases involving the right coronary artery, 6 of the 35 cases in the left anterior descending artery, 2 of the 11 cases of the left circumflex artery, and in the 1 case of saphenous vein bypass graft. There was significantly more erythrocyte component in the thrombi from the right coronary artery (28.7 +/- 30.1%) than in those from the left coronary artery (12.1 +/- 18.4%). CONCLUSION: Coronary artery thrombi in AMI are composed principally of platelets. Atherosclerotic cells were identified within thrombi from some patients. In the right coronary artery there were many more thrombi that were rich in erythrocytes than in thrombi from the left coronary artery.

Characterization of in vitro gutlike organ formed from mouse embryonic stem cells.

Using an embryoid body (EB) culture system, we have made a functional organlike cluster: the "gut" from embryonic stem (ES) cells (ES gut). There are many types of ES clusters, because ES cells have a pluripotent ability to develop into a wide range of cell types. Before inducing specific differentiation by exogenously added factors, we characterized comprehensive physiological and morphological properties of ES guts. Each ES gut has a hemispherical (or cystic) structure and exhibits spontaneous contractions [mean frequency: 13.5 +/- 8.8 cycles per min (cpm)]. A dense distribution of interstitial cells of Cajal (ICC) was identified by c-Kit immunoreactivity, and specific subcellular structures of ICC and smooth muscle cells were identified with electron microscopy. ICC frequently formed close contacts with the neighboring smooth muscle cells and occasionally formed gap junctions with other ICC. Widely propagating intracellular Ca(2+) concentration oscillations were generated in the ES gut from the aggregates of c-Kit immunopositive cells. Plateau potentials, possibly pacemaker potentials in ICC, and electrical slow waves were recorded for the first time. These events were nifedipine insensitive, as in the mouse gut. Our present results indicate that the rhythmic pacemaker activity generated in ICC efficiently spreads to smooth muscle cells and drives spontaneous rhythmic contractions of the ES gut. The present characterization of physiological and morphological properties of ES gut paves the way for making appropriate models to investigate the origin of rhythmicity in the gut.