Understanding the gastrointestinal physiology and responses to feeding in air-breathing Anabantiform fishes.

The Mekong Delta is host to a large number of freshwater species, including a unique group of facultative air-breathing Anabantiforms. Of these, the striped snakehead (Channa striata), the climbing perch (Anabas testudineus), the giant gourami (Osphronemus goramy) and the snakeskin gourami (Trichogaster pectoralis) are major contributors to aquaculture production in Vietnam. The gastrointestinal responses to feeding in these four species are detailed here. Relative intestinal length was lowest in the snakehead, indicating carnivory, and 5.5-fold greater in the snakeskin, indicating herbivory; climbing perch and giant gourami were intermediate, indicating omnivory. N-waste excretion (ammonia-N + urea-N) was greatest in the carnivorous snakehead and least in the herbivorous snakeskin, whereas the opposite trend was observed for net K+ excretion. Similarly, the more carnivorous species had a greater stomach acidity than the more herbivorous species. Measurements of acid-base flux to water indicated that the greatest postprandial alkaline tide occurred in the snakehead and a potential acidic tide in the snakeskin. Additional findings of interest were high levels of both PCO2 (up to 40 mmHg) and HCO3 - (up to 33 mM) in the intestinal chyme of all four of these air-breathing species. Using in vitro gut sac preparations of the climbing perch, it was shown that the intestinal net absorption of fluid, Na+ and HCO3 - was upregulated by feeding but not net Cl- uptake, glucose uptake or K+ secretion. Upregulated net absorption of HCO3 - suggests that the high chyme (HCO3 - ) does not result from secretion by the intestinal epithelium. The possibility of ventilatory control of PCO2 to regulate postprandial acid-base balance in these air-breathing fish is discussed.

Diffuse Intrasinusoidal Hepatic Metastasis from Breast Cancer Presenting as Liver Failure: Effective and Rapid Treatment with Weekly Low-Dose Adriamycin.

BACKGROUND Hepatic metastasis is well known in breast cancer. Approximately 12-20% of breast cancer patients will develop liver metastasis, which usually presents as discrete mass lesions. Rarely, metastatic spread can be so diffuse that it is unidentifiable on imaging but can progress to fulminant hepatic failure. Our case report suggests that clinicians need to have a high index of suspicion when patients present with rapidly decompensating liver failure in the absence of discrete radiologic hepatic lesions, and that weekly Adriamycin should be considered as a first-line therapeutic option. CASE REPORT A 28-year-old African American woman with a history of locally advanced estrogen receptor-positive, progesterone receptor-negative, and HER2-negative breast cancer presented with right upper quadrant abdominal pain and bilateral lower extremity swelling. She had been treated 3 years prior with neoadjuvant Adriamycin/cyclophosphamide - Taxol, bilateral mastectomies, radiation therapy, and tamoxifen. Diagnostic imaging revealed massive hepatomegaly and extensive areas of liver ischemia/necrosis without discrete masses or arterial/venous thrombosis. Biopsy of the liver revealed metastatic carcinoma diffusely infiltrating the hepatic sinusoids. Extensive work up for other etiologies of liver disease was negative. The patient's liver function quickly decompensated over several days. She was treated with weekly single-agent low-dose Adriamycin, and this resulted in successful reversal of her liver function tests back to baseline. CONCLUSIONS In addition to having a high index of suspicion for diffuse intrasinusoidal hepatic metastasis, physicians should consider weekly low-dose Adriamycin as a first-line therapeutic option for patients with progressive liver failure and biopsy-confirmed metastatic carcinoma diffusely infiltrating the hepatic sinusoids.