Biomedical subjects

W N Adams

Publications and source records attributed to W N Adams.

5 recordsLinked to original sources

PubMed1984

Human pathogenic viruses at sewage sludge disposal sites in the Middle Atlantic region.

Human enteric viruses were detected in samples of water, crabs, and bottom sediments obtained from two sewage sludge disposal sites in the Atlantic Ocean. Viruses were isolated from sediments 17 months after the cessation of sludge dumping. These findings indicate that, under natural conditions, viruses can survive for a long period of time in the marine environment and that they may present potential public health problems to humans using these resources for food and recreation. The isolation of viruses in the absence of fecal indicator bacteria reinforces previous observations on the inadequacy of these bacteria for predicting the virological quality of water and shellfish.

Enterobacteriaceae↗

PubMed1984

Drug-resistant bacteria in Continental Shelf sediments.

Fecal indicator bacteria were isolated from water and sediment samples obtained from a sewage sludge disposal site in the Middle Atlantic. Some were found to be resistant to several antimicrobial agents. Isolation of these microbes 30 months after cessation of sludge dumping indicates their survivability in the environment.

Bacteria↗

PubMed1980

Commentary on AOAC method for paralytic shellfish poisoning.

Paralytic shellfish poisoning (PSP) is caused by ingesting bivalve molluscan shellfish which have fed on the toxigenic marine dinoflagellates Gonyaulax catanella or G. tamarensis. The toxins from these organisms are neurotoxic alkaloids which interfere with nerve conduction and block muscle-action potential. The U.S. Food and Drug Administration cooperates with state shellfish control officials in the National Shellfish Sanitation Program to prevent marketing of toxin-contaminated shellfish. The toxins are quantitated by the standard mouse bioassay method, as found in Official Methods of Analysis of the AOAC. This paper discusses the procedure followed in the standard bioassay method in an attempt to clarify for the PSP analyst the rather complex official methodology, and, thus, promote more uniform results among laboratories.

Animals↗

PubMedDate not supplied

Variability of mouse bioassay for determination of paralytic shellfish poisoning toxins.

Toxic shellfish extracts and paralytic shellfish poison (PSP) standard solutions, tested over a range of pH levels, storage conditions, and temperatures, were monitored for toxin concentration, using the mouse bioassay and thin layer chromatography (TLC). A comparison of PSP toxin concentrations in toxic shellfish extracts and PSP standard solutions when dilution was varied suggests that other factors in the shellfish extracts contribute to the toxicity in mice; the closet agreement was at the death time range of 5-8 min. The toxicities of PSP standard solutions at pH levels ranging from 2 to 6 and held at 4 degrees C for various times were relatively constant; however, there was a gradual decrease in toxicity with pH 6 solutions. Also, standard solutions (pH 6) held at 4 degrees C for 28 days showed a 50% decrease in toxicity when the pH was adjusted to 2. TLC analyses of PSP standard solutions and toxic shellfish extracts revealed multiple spots at the Rf ranges of saxitoxin/neosaxitoxin and gonyaulax toxins I-IV. PSP standard solutions usually had a single spot in the saxitoxin/neosaxitoxin area. No attempt was made to confirm the identity of these compounds. Previously tested toxic shellfish extracts with subsequent pH adjustment to 1.5 and additional heat treatment (100 degrees C for 5 min) showed no appreciable difference in mouse toxicity. The use of antifoaming agents during the acid extraction step did not affect the final amounts of PSP obtained.

Animals↗

PubMedDate not supplied

Evaluation of laboratory performance of the AOAC method for PSP toxin in shellfish.

Laboratory performance of the official AOAC method for paralytic shellfish poison (PSP) toxin in shellfish was evaluated. Two series of naturally toxic shellfish split samples were distributed (15 in 1979 and 19 in 1982) to state shellfish-monitoring laboratories which participate in the National Shellfish Sanitation Program. The laboratories performed bioassays on duplicate 100 g portions of each 220 g split sample. Bioassays were consistent among the laboratories and compared favorably with those of previous studies.

Animals↗