Oxygen deficit determinations for a major river in eastern Hong Kong, China.

Determination of oxygen deficit in the Hong Kong Shing-Mun River was based on the oxygen uptake by water, algal respiration and river sediment and the oxygen supplied to the river by surface reaeration and algal photosynthesis. A systematic study was conducted to examine the effect of water temperature, flow velocity and water depth on both the oxygen demands and the oxygen supplies. The oxygen budget of a water column in a selected section of the river was modeled. The results of the oxygen budget analysis showed that when water temperature was around 10 degrees C (the lowest temperature in the river), no deficit was observed. When water temperature was 10 degrees C to 20 degrees C, a small oxygen deficit appeared, especially in the deeper water. At the highest water temperature (30 degrees C), the oxygen deficit was maximal, -6.84 g O2/m2/day, in the night-time during the Spring tide period.

Ischemic colitis: CT evaluation of 54 cases.

PURPOSE: To review the computed tomographic (CT) scans and medical records of 54 patients with proved ischemic colitis, define the spectrum of CT findings, and assess the effect of CT imaging on treatment. MATERIALS AND METHODS: The mean age of the patients was 72 years. CT scans were analyzed for the presence of colonic abnormalities and associated findings. Ischemia was clinically unsuspected in 16 patients (30%). RESULTS: Segmental involvement was seen in 48 patients (89%), with a mean length of involvement of 19 cm (range, 5-38 cm). Wall thickness varied between 2 and 20 mm (mean, 8 mm). All parts of the colon were involved. The CT appearance of the colonic wall varied: (a) A wet appearance with heterogeneous areas of edema was seen in 33 patients (61%). (b) A dry appearance with mild homogeneous thickening was seen in 18 patients (33%). (c) Intramural air was present in three patients (6%). Ischemia resolved in 41 patients (76%), and complications occurred in 13 patients (24%). CONCLUSION: CT can be used to confirm the clinical suspicion of ischemic colitis, to suggest ischemia when it is unsuspected, and to diagnose complications. Intrinsic colonic abnormalities cannot be used to diagnose or predict the development of infarction.

Multiple hamartoma syndrome with osteosarcoma.

Multiple hamartoma syndrome, also known as Cowden's disease, is a rare genodermatosis with characteristic mucocutaneous lesions associated with multiple internal abnormalities. We describe a patient having classic dermatologic manifestations of Cowden's disease and multiple neoplasia including follicular adenocarcinoma of the thyroid gland with lung metastasis, intraductal breast carcinoma within a fibroadenoma, and an osteosarcoma. To our knowledge, this is the first reported case of an osteosarcoma in Cowden's disease.