Food safety implications of the distribution of azaspiracids in the tissue compartments of scallops (Pecten maximus).

Azaspiracids, a new class of shellfish toxins, have been implicated in several recent incidents of human intoxications following the consumption of mussels (Mytilus edulis). A study was undertaken to examine the distribution of azaspiracid poisoning (AZP) toxins in scallops (Pecten maximus) and individual shellfish were dissected into five tissue fractions for the determination of toxin composition. Separation of the predominant azaspiracids, AZA1-3, was achieved using reversed-phase liquid chromatography with detection by positive electrospray multiple tandem mass spectrometry. The AZP toxin composition was determined in the adductor muscle (meat), gonad (roe), hepatopancreas (digestive glands), mantle and gill of scallops. Substantial differences in the AZP toxin levels between tissue compartments were observed and toxins were concentrated predominantly, about 85%, in the hepatopancreas. There was also a significant variation in the total toxin levels between individual scallops from the same sample batch and the RSD was 60% (n = 9). Interestingly, although all three AZP toxins were present in phytoplankton and mussels, AZA3 was not detected in the scallop samples examined. It was concluded that to improve food safety, only the adductor muscle and gonad of scallops should be permitted for sale to the public.

Azaspiracid shellfish poisoning: unusual toxin dynamics in shellfish and the increased risk of acute human intoxications.

A number of recent acute human intoxications in Europe from the consumption of Irish mussels have been attributed to the presence of a new class of toxins named azaspiracids. The study demonstrates that azaspiracids behave differently from other polyether toxins, and this accounts for most false-negative results in the mouse bioassay employed by regulatory agencies to detect azaspiracids. Typically, polyether toxins are concentrated in the digestive glands of shellfish, but this is not always the situation with azaspiracids. Liquid chromatography-mass spectrometry (LC-MS), especially multiple tandem MS methods, have been applied to demonstrate that azaspiracid (AZA1) and its methyl- and demethyl- analogues, AZA2 and AZA3 respectively, are distributed throughout shellfish tissues. Using conventional mouse bioassay protocols, only 0-40% of the total azaspiracid content of shellfish was used in the assay, which could directly account for false-negative results. It was also observed that the toxin profiles differed significantly in various mussel tissues with AZA1 as the predominant toxin in the digestive glands and AZA3 predominant in the remaining tissues.

Liquid chromatography with electrospray ion trap mass spectrometry for the determination of five azaspiracids in shellfish.

Azaspiracid poisoning (AZP) is a new human toxic syndrome that is caused by the consumption of shellfish that have been feeding on harmful marine microalgae. A liquid chromatography-mass spectrometry (LC-MS) method has been developed for the determination of the three most prevalent toxins, azaspiracid (AZA1), 8-methylazaspiracid (AZA2) and 22-demethylazaspiracid (AZA3) as well as the isomeric hydroxylated analogues, AZA4 and AZA5. Separation of five azaspiracids was achieved on a C18 column (Luna-2, 150 x 2 mm, 5 microm) with isocratic elution using acetonitrile-water containing trifluoroacetic acid and ammonium acetate as eluent modifiers. Using an electrospray ionisation (ESI) source with an ion-trap mass spectrometer, the spectra showed the protonated molecules, [M+H]+, with most major product ions due to the sequential loss of two water molecules. A characteristic fragmentation pathway that was observed in each azaspiracid was due to the cleavage of the A-ring at C9-C10 for each toxin. It was possible to select unique ion combinations to distinguish between the isomeric azaspiracids, AZA4 and AZA5. Highly sensitive LC-MS3 analytical methods were compared and the detection limits were 5-40 pg on-column. Linear calibrations were obtained for AZA1 in shellfish in the range 0.05-1.00 microg/ml (r2 = 0.9974) and good reproducibility was observed with a relative standard deviation (%RSD) of 1.8 for 0.9 microg AZAI/ml (n=5). The %RSD values for the minor toxins, AZA4 and AZA5, using LC-MS3 (A-ring fragmentation) were 12.3 and 8.1 (0.02 microg/ml; n=7), respectively. The selectivity of toxin determination was enhanced using LC-MS-MS with high energy WideBand activation.

Knowledge and attitudes to prescribed drugs in young and elderly patients.

Increasing patient knowledge of drug therapy is said to improve compliance and may reduce adverse drug reactions. We assessed patient knowledge of prescribed drugs in fifty patients attending a hypertension clinic [outpatients] and in elderly patients on admission to (n = 129) and on discharge from (n = 100) an acute geriatric assessment unit. We found that 88% of outpatients, 40% of elderly admissions, and 41% of elderly discharges knew the indications for their therapy; only 40% of outpatients, 8% of elderly admissions and 12% of elderly discharges could name their medications. Patients said that their information came principally from the prescribing doctor. In a further study we assessed doctor, nurse, young and elderly patients' ability to discriminate between commonly prescribed white tablets. Errors were made by the doctors on 25% occasions, nurses on 40% occasions and patients on 61% occasions. Young patients made errors 67% of the time and elderly patients 55% of the time. These studies indicate that both inpatients and outpatients, both young and elderly have poor knowledge of their medications. In addition, many commonly prescribed drugs are not easily distinguishable by patient, prescriber or drug administrator. We conclude that there is a need to improve knowledge both in patients and in prescribers. We suggest that prescribers should consider the colour and shape of medications prescribed concurrently as many "little white tablets" are difficult to tell apart.

Relieving nausea and vomiting in patients with cancer: a treatment algorithm.

PURPOSE/OBJECTIVES: To describe a treatment algorithm for the choice of antiemetic therapy for the patient receiving chemotherapy. DATA SOURCES: Published literature, data collected on an inpatient oncology unit. DATA SYNTHESIS: Because little information is available to systematically guide clinicians in choosing the best antiemetic for an individual patient who is receiving a particular chemotherapy protocol, a treatment algorithm was developed. The four main variables include emetogenicity of the protocol, patient's age, previous adverse reaction to antiemetics, and failure of previous antiemetics. Other factors to consider include alcohol use, anticipatory nausea, patient health status, nausea history not related to chemotherapy, and type and availability of IV access. CONCLUSION: The use of this algorithm resulted in appropriate choice of antiemetics and improved patient outcomes associated with reduced incidence of nausea and vomiting. IMPLICATIONS FOR NURSING PRACTICE: Nurses can have a significant impact on a patient's experience with chemotherapy treatment by improving symptom management of nausea and vomiting.