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Red swamp crayfish (Procambarus clarkii) were placed for a period of 7 days in Bayou Trepagnier, a Louisiana waterway which received petroleum-laden effluents from a manufacturing complex several decades ago. However, coolant water from the plant continued to be released into the bayou until 1995. Analyses of sediments at the exposure site revealed heavy contamination by lead, chromium, and copper, while concentrations of arsenic and cadmium were very low. Significant bioaccumulation of lead was observed in the hepatopancreas and gills of 7-day-exposed crayfish, whereas chromium accumulated the most in the gills and blood. Concentrations of copper in the crayfish did not change during the course of the study, suggesting that this essential metal constituent of the respiratory pigment is successfully regulated even when crayfish are exposed to relatively high levels of copper in the sediments. There was no metal accumulation in the abdominal muscle of the crayfish. That damage to the hepatopancreas occurred during the exposure is suggested by histopathological studies which revealed swollen and vacuolated R cells and an increase in the pH of the digestive juices. Blood glucose levels, as well as ovarian and hepatopancreatic indices, were unchanged. This study demonstrates that accumulation of nonessential metals in crayfish tissues in a wetland environment contaminated by mixed pollution (metals and hydrocarbons) reflects the concentrations of metals in the sediment.

The kinetics of substrate uptake by heterotrophic microbial populations was examined at three depths over a broad area of the eastern tropical Pacific Ocean. Ten different "Clabeled compounds were used as substrates. In many cases uptake data could not be used in the conventional manner to dctcrmine the kinetic constants because of tither extremely low levels of uptake or extreme variability in uptake from one substrate concentration to another. Neither occurrence of usable uptake patterns nor the level of uptake at the 100 lug C liter-' level of added substrate appeared to correlate with specific in situ variations in descriptive parameters.A strong correlation was observed between the uptake of proline (100 pug C liter-') and the concentration of viable bacteria as determined by plate counts.

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BACKGROUND. Survival for adenocarcinoma of the pancreatic remains unchanged over the last two decades. The majority of patients (85%) are diagnosed with an inoperable tumor. Patterns of failure reveal that pancreatic cancer involves three compartments: the pancreatic bed and regional lymph nodes, the liver and the peritoneal surfaces. Twelve patients with advanced, unresectable pancreatic cancer, Stage II/III, were treated with regional intra-arterial chemotherapy and extracorporeal hernofiltration directed towards the pancreatic tumor-bearing area and the liver. METHODS.Five patients had an arterial catheter/port system placed within the celiac axis; the rest had an angiographically placed arterial catheter. All patients had a 16 Fr PFM filtration catheter inserted in the vena cava positioning the tip at the level of the diaphragm and then connected to a hemofiltration unit. Mitomycin C was infused over 25 minutes followed by 5-FU over 10 minutes. The hemofiltration was begun before the drug infusion and continued for 70 minutes. The twelve patients underwent 33 cycles of regional chemotherapy plus hemofiltration. RESULTS.Five patients had a partial response (45.5%), five had stable disease (45.5%), and one had progression (9%). Four patients were re-explored with one patient undergoing a curative resection. The average survival for patients with unresectable pancreatic adenocarcinoma is 13 months. Tumor implantation and progression on the peritoneal surfaces remains the major site of treatment failure. CONCLUSIONS. Regional chemotherapy plus hemofiltration with MMC and 5-FU appears to improve the response of Stage WIII inoperable pancreatic cancer and can convert some patients to resectability without significant complications and with no mortality.