Histological study of gallbladder and bile duct epithelia in patients with anomalous arrangement of the pancreaticobiliary ductal system: comparison between those with and without a dilated common bile duct.

BACKGROUND: We histologically evaluated the epithelia of the gallbladder (GB) and bile duct (BD) in patients with anomalous arrangement of the pancreaticobiliary ductal system (AAPB), with regard to the shape of the common BD (CBD). METHODS: The GB and BD were studied histologically using surgical materials from 44 patients with AAPB: 27 with a dilated CBD (D-type) and 17 with a nondilated CBD (N-type). RESULTS: GB cancer and BD cancer were found in 11.1% and 3.7% of D-type and 17.6% and 0% of N-type respectively. Hyperplastic epithelium and atypical epithelium of the GB were frequently seen in both D-type (46%, 46%) and N-type (82%, 70%), while such epithelia of the BD were only seen in D-type (10%, 35%). The Ki67 labeling index of the nonneoplastic epithelium of the GB was high in both D-type (13.0%) and N-type (9.7%), though that of the BD was high in D-type (12.5%) but low in N-type (1.8%). The prevalences of pyloric gland metaplasia, intestinal metaplasia, and p53 protein overexpression of the nonneoplastic epithelium did not show any significant differences between D-type and N-type. CONCLUSIONS: It is suggested that the BD epithelium of N-type probably has a lower potential for developing malignancy than that of D-type, while the GB epithelia of both D-type and N-type have a high potential for developing malignancy. This might support the selection of simple cholecystectomy as the treatment of choice in AAPB patients of N-type, although further investigation of the BD epithelium is required in a larger number of such patients.

Structure and development of free neuromasts in barramundi, Lates calcarifer (Block).

This study was conducted to clarify the development of free neuromasts with growth of the barramundi, Lates calcarifer. A pair of free neuromasts was observed behind the unpigmented eyes in newly hatched eleutheroembryos with a mean total length of 1.93 mm, and two-hour-old eleuthero-embryos could respond to an approaching pipette. At 2 days after hatching, the egg yolk sac was mostly consumed, the eyes were pigmented, and the larvae commenced feeding on rotifers. Free neuromasts increased in number with growth and commenced developing into canal neuromasts in barramundi 15 days old with a mean total length of 8.07 mm. The average length of the major axis of the trunk free neuromasts attained approximately 12.9-15.5 microm, and the number of sensory cells was 15.4-17.5 at 15-20 days old. Developed cupulae of free neuromasts were observed in 1-day-old eleutheroembryos. The direction of maximum sensitivity of free neuromasts, determined from the polarity of the sensory cells, coincided with the minor axis of the lozenge-shaped outline of the apical surface of the free neuromasts. The polarity of trunk neuromasts was usually oriented along the antero-posterior axis of the fish body, but a few had a dorso-ventral direction. On the head, free neuromasts were oriented on lines tangential to concentric circles around the eye.