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PubMed2005

Estimation of daily exposure to 4-hydroxy-2-alkenals in Korean foods containing n-3 and n-6 polyunsaturated fatty acids.

4-Hydroxy-2-alkenals are cytotoxic aldehydes generated from the oxidation of n-3 and n-6 polyunsaturated fatty acids. The compounds have shown various biological effects via Schiff base adducts or Michael addition adducts at levels higher than physiological ones. To assess human exposure to 4-hydroxy-2-alkenals in the diet, 4-hydroxy-2-alkenals in vegetable oils, fish and shellfish were monitored using GC/MS/SIM. 2001 National Health and Nutrition Survey (2002) data were employed for the dietary intake pattern. The Korean daily exposure to 4-hydroxy-2-alkenals, excluding a possible one from fried food, was 4.3 microg day-1, constituted of 1.6 microg 4-hydroxy-2-hexenal (HHE) and 2.7 microg 4-hydroxy-2-nonenal (HNE). It was calculated that Koreans could be additionally exposed to more than 11.8 microg day-1 4-hydroxy-2-alkenal from fried foods. Thus, the combined exposure would be 16.1 microg day-1, which corresponds to 0.3 microg kg-1 body weight day-1 for a 60 kg Korean adult. In spite of the biological toxicity of 4-hydroxy-2-alkenals, the risk for human could not be quantified due to the lack of a virtually safe dose of the compounds. However, considering the basal level of 4-hydroxy-2-alkenals in many tissues, the present value from the diet may not pose a significant risk for human health.

Adult↗

PubMed2006

Quantification of seven arsenic compounds in seafood products by liquid chromatography/electrospray ionization-single quadrupole mass spectrometry (LC/ESI-MS).

A liquid chromatography/electrospray ionization-single quadrupole mass spectrometry (LC/ESI-MS) method was developed to quantify seven arsenic compounds: arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AB), trimethylarsine oxide (TMAO), arsenocholine (AC) and tetramethylarsonium ion (TEMA), widely found in seafood. The arsenicals separated by anion- or cation-exchange LC were all readily identified under the optimized ESI-MS conditions. Linear calibration curves constructed by plotting the peak area counts of molecular ions against the arsenic concentrations were obtained for all seven arsenic compounds. The limits of quantification (S/N = 10) were 800, 600, 50, 10, 5, 5 and 5 ng ml-1 for As(V), MMA, DMA, AB, TMAO, AC and TEMA, respectively. The LC/ESI-MS method was found to be useful to quantify arsenic compounds in seafood by model experiments using the mid-gut gland and muscle of a shellfish (Buccinid whelks). Spiking experiments verified the accuracy of the method.

Animals↗

PubMedDate not supplied

An investigation of the availability of 137Cs and 239 + 240Pu for gut absorption in winkles following cooking and in vitro simulated gastro-intestinal digestion.

The consumption of plutonium, americium and radiocaesium in locally collected shellfish is an important contributor to the radiation dose received by seafood consumers living in West Cumbria. Only a small fraction of the actinide activity is assumed to be absorbed via the gut whilst it is assumed that all the radiocaesium is. Solubilization studies reported here using an in vitro digestion method support the former assumption but not the latter, suggesting that the proportion of the 137Cs available for absorption could be significantly smaller than unity where a large percentage of the ingested Cs is adsorbed onto inorganic sedimentary material. Such a situation arises near the Sellafield nuclear-reprocessing plant where a high proportion of the radiocaesium (and plutonium) in the winkles collected locally and subsequently cooked is associated with inorganic particulate matter.

Biological Availability↗

PubMedDate not supplied

Recent methods for detection of seafood toxins: recent immunological methods for ciguatoxin and related polyethers.

A brief summation of the methods for detection of each of the marine toxins is presented in this report. The toxins are brevetoxin (PbTx), palytoxin (PTX), okadaic acid (OA), paralytic shellfish toxins (PSP) and ciguatoxin (CTX). The immunological and biotechnical procedures developed for each of these toxins are reviewed. Details of the recent methodology (solid-phase immunobead assay) for detection of ciguatoxin and related polyethers with monoclonal antibodies and receptors are presented. The capabilities of immunological technology for assessment of toxins in seafood products are promising and will probably be widely used in the future for seafood monitoring.

Animals↗

PubMedDate not supplied

The use of Daphnia magna for detection of okadaic acid in mussel extracts.

Okadaic acid (OA), the main toxin responsible for diarrheic shellfish poisoning (DSP) has toxicity for Daphnia magna (EC50 = 15 +/- 1.8 micrograms/l). A Daphnia bioassay was developed and used to analyse okadaic acid in mussel extracts. A linear correlation was found between OA concentration determined by the Daphnia bioassay and by HPLC assay (r = 0.85; p < 0.001). The Daphnia bioassay can measure OA levels 10 times below the threshold of the mouse bioassay method. It is an inexpensive sensitive tool which can be used in replacement of mouse bioassay for the screening of OA and some co-extracting toxins in mussel extracts.

Animals↗

PubMed1991

Light and scanning electron microscopic studies on effects of marine algal toxins toward freshly prepared hepatocytes.

Mussels exposed to dinoflagellates may represent a human health risk due to accumulation of a variety of algal toxins. In several parts of the world, algal toxins leading to diarrhea (diarrhetic shellfish poisons, DSP) are found in mussels for extended periods of the year. Routine monitoring of these toxins involves ip injections in mice. Chemical analytical methods have been developed for only some of the toxins in question, namely, those giving diarrhea. Other toxins in the DSP complex are not easily detected by analytical methods. In this report we show that freshly prepared hepatocytes from rats are a convenient means to differentiate between the toxins that give diarrhea and those that do not. Consequently, hepatocytes can be useful in both screening and as a tool in the process of developing analytical methods. Freshly prepared hepatocytes might be useful in combination either with the mouse bioassay or with chemical analytical methods.

Animals↗

PubMed1972

Permeability of intestinal capillaries. Pathway followed by dextrans and glycogens.

The pathway followed by macromolecules across the wall of visceral capillaries has been studied by using a set of tracers of graded sizes, ranging in diameter from 100 A (ferritin) to 300 A (glycogen). Polysaccharide particles, i.e. dextran 75 (mol wt approximately 75,000; diam approximately 125 A), dextran 250 (mol wt 250,000; diam approximately 225 A), shellfish glycogen (diam approximately 200 A) and rabbit liver glycogen (diam approximately 300 A), are well tolerated by Wistar-Furth rats and give no vascular reactions ascribable to histamine release. Good definition and high contrast of the tracer particles were obtained in a one-step fixation-in block staining of the tissues by a mixture containing aldehydes, OsO(4) and lead citrate in phosphate or arsenate buffer, pH 7.4, followed by lead staining of sections. The glycogens and dextrans used move out of the plasma through the fenestrae and channels of the endothelium relatively fast (3-7 min) and create in the pericapillary spaces transient (2-5 min) concentration gradients centered on the fenestrated sectors of the capillary walls. The tracers also gained access to the plasmalemmal vesicles, first on the blood front and subsequently on the tissue front of the endothelium. The particles are temporarily retained by the basement membrane. No probe moved through the intercellular junctions. It is concluded that, in visceral capillaries, the fenestrae, channels, and plasmalemmal vesicles, viewed as related parts in a system of dynamic structures, are the structural equivalent of the large pore system.

Animals↗

PubMed2003

Cholera and other types of vibriosis: a story of human pandemics and oysters on the half shell.

Vibrios are ubiquitous in the aquatic environment and are commonly present in or on shellfish and other seafood. A small subset of strains/species are able to cause human disease, including the cholera toxin-producing strains of Vibrio cholerae that are responsible for epidemic/pandemic cholera; thermostable direct hemolysin-producing strains of Vibrio parahaemolyticus; and Vibrio vulnificus, which can cause fulminant sepsis. Cholera outbreaks can be initiated by transmission of "epidemic" V. cholerae strains from their environmental reservoir to humans through seafood or other environmentally related food or water sources. "Nonepidemic" strains of V. cholerae and strains of other Vibrio species, including V. parahaemolyticus and V. vulnificus, are generally acquired by eating seafood (particularly raw oysters/oysters on the half shell). Although the primary clinical manifestation of infection with these strains is gastroenteritis, they can also cause wound infections and (particularly for V. vulnificus) septicemia in persons who have liver disease or are immunocompromised.

Animals↗

PubMed1998

The role of Gulf Coast oysters harvested in warmer months in Vibrio vulnificus infections in the United States, 1988-1996. Vibrio Working Group.

Vibrio vulnificus infections are highly lethal and associated with consumption of raw shellfish and exposure of wounds to seawater. V. vulnificus infections were reported to the Centers for Disease Control and Prevention from 23 states. For primary septicemia infections, oyster trace-backs were performed and water temperature data obtained at harvesting sites. Between 1988 and 1996, 422 infections were reported; 45% were wound infections, 43% primary septicemia, 5% gastroenteritis, and 7% from undetermined exposure. Eighty-six percent of patients were male, and 96% with primary septicemia consumed raw oysters. Sixty-one percent with primary septicemia died; underlying liver disease was associated with fatal outcome. All trace-backs with complete information implicated oysters harvested in the Gulf of Mexico; 89% were harvested in water >22 degrees C, the mean annual temperature at the harvesting sites (P < .0001). Control measures should focus on the increased risk from oysters harvested from the Gulf of Mexico during warm months as well as education about host susceptibility factors.

Adolescent↗

PubMed2004

Epidemiology, pathogenesis, and prevention of foodborne Vibrio parahaemolyticus infections.

Since its discovery about 50 years ago, Vibrio parahaemolyticus has been implicated as a major cause of foodborne illness around the globe. V. parahaemolyticus is a natural inhabitant of marine waters. Human infections are most commonly associated with the consumption of raw, undercooked or contaminated shellfish. A few individual V. parahaemolyticus virulence factors, including the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH), have been investigated in depth, yet a comprehensive understanding of this organism's ability to cause disease remains unclear. Since 1996, serotype O3:K6 strains have been associated with an increased incidence of gastroenteritis in India and in Southeast Asia, and with large-scale foodborne outbreaks in the United States (US). In light of the emerging status of pathogenic V. parahaemolyticus, the US Food and Drug Administration conducted a microbial risk assessment to characterize the risk of contracting V. parahaemolyticus infections from consuming raw oysters. This review summarizes epidemiological findings, discusses recognized and putative V. parahaemolyticus virulence factors and pathogenicity mechanisms, and describes strategies for preventing V. parahaemolyticus infections.

Animals↗

PubMed1982

Increased proportion of arachidonic acid in plasma lipids after 2 weeks on a diet of tropical seafood.

Using capillary GLC we analyzed the plasma fatty acids in a group of full-blood Aborigines in north western Australia before and after 2 wk on a diet in which over 90% of the energy was derived from tropical fish and shellfish. The proportion of saturated fatty acids did not change and all monoenoic and omega 6 fatty acids, except arachidonic, fell significantly. The proportions of arachidonic and all omega 3 PUFA rose significantly on the diet. This striking rise in arachidonic was evident in all lipid fractions (phospholipids, cholesterol esters, and triglycerides). Total triglycerides in fasting plasma fell from 1.32 to 0.61 mM after the diet while total cholesterol, which was low initially, did not fall significantly. Analysis of the fatty acids in lipid extracts from the tropical seafood eaten in the study revealed an arachidonic acid content ranging from 4.8 to 14.3% of the total fatty acids. The seafood contained almost no linoleic acid but was, as expected, a rich source of omega 3 fatty acids (13.6 to 31.0% of the total fatty acids). From these data we are able to conclude that seafood from tropical waters, unlike seafood from colder waters, is a natural source of polyunsaturated fatty acids from both the omega 6 and omega 3 series.

Animals↗

PubMed1994

Severe gastroenteritis associated with Vibrio hollisae infection: report of two cases and review.

Vibrio hollisae, one of the more recently described halophilic Vibrio species, is infrequently associated with gastrointestinal disease and only rarely recovered from individuals presenting with gram-negative sepsis. In this report we describe two cases of severe gastrointestinal disease associated with V. hollisae in otherwise healthy individuals. In one of these individuals, severe epigastric pain was apparently associated with signs of pseudoappendicitis, necessitating exploratory surgery. In both individuals, infection was associated with the ingestion of raw shellfish. These cases are discussed in light of previous reports on the epidemiology, pathogenesis, and spectrum of disease caused by this unusual pathogen.

Adult↗

PubMed1982

Sporadic non-A, non-B hepatitis: frequency and epidemiology in an urban U.S. population.

Patients with acute viral hepatitis were identified at five hospitals in Baltimore, Maryland between February 1979-August 1980. Of the 295 patients with serologically diagnosed hepatitis, 42% had non-A, non-B hepatitis; 48% had hepatitis B; and 10% had hepatitis A. Compared with matched control patients with no liver disease, patients with non-A, non-B hepatitis more often had received a blood transfusion (11% vs. O, P less than 0.001), used parenteral drugs (42% vs. 4%, P less than 0.001), were employed as health workers in direct patient care or hospital laboratory work (6% vs. 3%, P less than 0.05), had personal contact with others who had hepatitis (16% vs. 1%, P less than 0.001), or had ingested raw shellfish (34% vs. 20%, P less than 0.01). A history of previous clinical hepatitis and serologic markers indicating previous hepatitis B infection were found in patients with non-A, non-B hepatitis more often than in the control patients. Chronic non-A, non-B hepatitis was found in 34 (42.5%) of 80 patients with non-A, non-B hepatitis.

Adolescent↗

PubMed1977

Cholera in Portugal, 1974.I. Modes of transmission.

In April-November 1974, Portugal had a cholera epidemic caused by Vibrio cholerae El Tor Inaba with 2467 bacteriologically confirmed hospitalized cases and 48 deaths. Most of the country was affected, with 17 of the 18 districts reporting cases. V. cholerae was isolated from 42 per cent of shellfish tested during the epidemic, and an epidemiologic study found that a history of consumption of raw or poorly cooked cockles was significantly more common among cholera patients than among paired controls. Water from a spring and a brand of commercially bottled water were also found to be vehicles of transmission of cholera. Although night soil was sometimes used on gardens, consumption of raw fruits and vegetables was not associated with illness.

Cholera↗

PubMed2006

Cholera-like presentation in Vibrio fluvialis enteritis.

We describe a patient who presented with cholera-like diarrhea seven days after eating shellfish at a seafood buffet on the Gulf Coast. The patient's stool culture grew only Vibrio fluvialis on TCBS agar, and his diarrhea and profound acidosis completely resolved within 24 hours of initiating antibiotics. To our knowledge, a detailed case of V fluvialis diarrhea with cholera-like symptoms has not been reported.

Aged↗

PubMed1997

Identification of a new genogroup of aquareovirus by RNA-RNA hybridization.

The relative mobilities of the 11 dsRNA genomic segments of 22 aquareovirus isolates from fish and shellfish obtained from different geographical areas of the world were compared by PAGE. Using reciprocal RNA-RNA dot blot hybridization, a new sixth genetic group of aquareovirus (genogroup F) was identified. Genogroup A was represented by eight and genogroup B by 12 isolates. The remaining two isolates represented the new sixth genogroup (genogroup F). The genetic relationship of these aquareoviruses with mammalian rotavirus group A (SA 11) was also examined by reciprocal RNA-RNA blot hybridization but none was found under any of the stringency conditions used.

Animals↗

PubMed1991

Plasmid associated virulence properties of environmental isolates of Aeromonas hydrophila.

The plasmid profiles, and their association with antimicrobial resistance, of 60 strains of Aeromonas hydrophila isolated from fish, shellfish and water were investigated. Only two strains were susceptible to all the antimicrobial agents tested; the highest incidences of resistance were to tetracycline (96.7%), prystanamycin (93.3%), ampicillin (91.7%) and cephalothin (91.7%). Forty strains harboured one or more plasmids and the plasmid profile most frequently detected (15%) was the association of three small plasmids of 4.2, 3.2 and 2.8 Mda. Curing experiments indicated that the plasmid-free derivative strains simultaneously lost their resistance determinants to tobramycin, neomycin, gentamicin and kanamycin. More than 90% of the strains tested produced siderophores and displayed haemolytic activity. However, the relationship between these virulence characters and the presence of plasmids was different; in 74.5% of the strains there was siderophore production and plasmids were detectable, whereas only 60% of the strains simultaneously possessed plasmids and haemolytic activity.

Aeromonas hydrophila↗

PubMed2005

A rapid and simple PCR analysis indicates there are two subgroups of Vibrio vulnificus which correlate with clinical or environmental isolation.

Vibrio vulnificus is an estuarine bacterium which is the causative agent of both food-borne disease and wound infection. Although V. vulnificus is commonly found in molluscan shellfish at high numbers, the incidence of disease is relatively low, leading to the hypothesis that not all strains of V. vulnificus are equally virulent. Unfortunately, there is currently no easy test to identify virulent strains of this species. We have previously identified a 200 bp randomly amplified polymorphic DNA (RAPD) PCR amplicon associated with clinical isolates. DNA sequence data from this locus in six clinical and four environmental isolates showed that the strains could be divided into two groups, which we termed C-type (correlates with clinical origin) and E-type (correlates with environmental origin). We designed PCR primers that could distinguish between the two groups, and typed 55 randomly selected strains. We found that 90% of the C-type strains were clinical isolates, while 93% of environmental isolates were classified as E-type. The region directly downstream of this locus contained a heptanucleotide sequence repeated various times depending on the strain. Using a PCR-based assay to detect the repeat number present in a given strain, we found a statistically significant correlation with the C/E type classification and the number of repeats. The data reported here are consistent with the existence of two genotypes of V. vulnificus, with the C-type being a strong indicator of potential virulence.

Animals↗