Irinotecan and Δ8-Tetrahydrocannabinol Interactions in Rat Liver: A Preliminary Evaluation Using Biochemical and Genotoxicity Markers.

There is growing interest regarding the use of herbal preparations based on Cannabis sativa for medicinal purposes, despite the poorly understood interactions of their main constituent Δ8-tetrahydrocannabinol (THC) with conventional drugs, especially cytostatics. The objective of this pilot study was to prove whether the concomitant intake of THC impaired liver function in male Wistar rats treated with the anticancer drug irinotecan (IRI), and evaluate the toxic effects associated with this exposure. IRI was administered once intraperitoneally (at 100 mg/kg of the body weight (b.w.)), while THC was administered per os repeatedly for 1, 3, and 7 days (at 7 mg/kg b.w.). Functional liver impairments were studied using biochemical markers of liver function (aspartate aminotransferase-AST, alanine aminotransferase-ALP, alkaline phosphatase-AP, and bilirubin) in rats given a combined treatment, single IRI, single THC, and control groups. Using common oxidative stress biomarkers, along with measurement of primary DNA damage in hepatocytes, the degree of impairments caused at the cellular level was also evaluated. THC caused a time-dependent enhancement of acute toxicity in IRI-treated rats, which was confirmed by body and liver weight reduction. Although single THC affected ALP and AP levels more than single IRI, the levels of liver function markers measured after the administration of a combined treatment mostly did not significantly differ from control. Combined exposure led to increased oxidative stress responses in 3- and 7-day treatments, compared to single IRI. Single IRI caused the highest DNA damage at all timepoints. Continuous 7-day oral exposure to single THC caused an increased mean value of comet tail length compared to its shorter treatments. Concomitant intake of THC slightly affected the levels of IRI genotoxicity at all timepoints, but not in a consistent manner. Further studies are needed to prove our preliminary observations, clarify the underlying mechanisms behind IRI and THC interactions, and unambiguously confirm or reject the assumptions made herein.

Seafood Allergy, Toxicity, and Intolerance: A Review.

Seafood allergies have been increasing their presence in the last 2 decades. Allergic reactions to seafood can range from mild urticarial and oral allergy syndrome to life-threatening anaphylactic reactions. Ingestion of seafood infested with Anisakis larvae can cause a disease known as anisakiasis with symptoms similar to true seafood allergy. Furthermore, some adverse reactions to seafood including histamine fish poisoning (HFP), and intolerance to histamine can trigger clinical symptoms, which, although nonallergic in origin, are similar to true immunoglobulin E (IgE)-mediated allergic reactions. Because seafood allergy usually remains a lifelong food allergy, this review focuses on the current knowledge on fish and shellfish allergens and emphasizes the importance of differentiating seafood allergy from other allergy-like reactions (anisakiasis, HFP, and intolerance to histamine). Key teaching points: • Fish and shellfish are potent allergens that can provoke serious IgE antibody-mediated adverse reactions in sensitive individuals. • Sensitization to seafood allergens can be achieved by ingestion, inhalation, or skin contact. • Shellfish major allergen, tropomyosin, shares significant homology to arthropods (dust mites and cockroaches). • Accidental exposures to seafood products cross-contaminated with fish or shellfish allergens (hidden allergens) during processing may present a health risk for sensitive individuals. • Allergens of fish parasite A. simplex present common hidden allergens in seafood, particularly in raw and undercooked home-made fish dishes. • Symptoms caused by HFP, histamine intolerance, and anisakiasis are similar to true seafood allergy.

Respiratory health and breath condensate acidity in sawmill workers.

PURPOSE: The aim of the study was to evaluate exhaled breath condensate acidity (EBC pH) as a biomarker of airway response to occupational respiratory hazards present in sawmill. METHODS: Sixty-one sawmill workers in total (26 from Sawmill 1 and 35 from Sawmill 2) provided EBC samples at the beginning and at the end of the working week. Respiratory symptoms, lung function, bronchodilator test and atopy status were assessed. Occupational environment was checked for the levels of respiratory hazards. RESULTS: Airborne dust concentrations were below threshold limit value. Endotoxin in Sawmill 1 and Sawmill 2, and moulds in Sawmill 1 were at the levels able to induce inflammatory response in the airways. Mould levels were 2.5 times higher in Sawmill 1 than in Sawmill 2. Compared to Sawmill 2 workers, lower spirometry values, higher prevalence of dry cough and positive bronchodilator test were found in Sawmill 1 workers. Monday EBC pH values did not differ between sawmills, but declined after one working week in Sawmill 1 workers (from 7.88 to 7.49, P = 0.012) and not in Sawmill 2 workers. Similar results were obtained when only respiratory healthy non-smokers were analysed. Monday-to-Friday change of other respiratory parameters was not observed. CONCLUSION: The results suggest EBC pH as a biomarker of acute respiratory effects related to occupational exposure to respiratory hazards in sawmills, presumably increased mould levels. The effect was present even at subclinical level, namely in respiratory healthy subjects. The long-term health implications remain unclear and should be evaluated in a follow-up study.

Prevention of poisonings by educational intervention aimed at parents of preschool children.

The aim of the study was to assess the effectiveness of the specific design of a poisoning prevention intervention. This controlled before-after study followed Solomon design for educational interventions using two groups (the educational intervention group and the control group). Participants comprised parents of children attending kindergartens under the jurisdiction of the City of Zagreb and in the vicinity of Zagreb. The intervention group (N = 336) underwent an educational intervention during parents' meetings comprising oral presentation by the Croatian Poison Control Centre (CPCC) and distribution of gift packages containing child-proof locks, flyers, and stickers with the CPCC contact number. After the intervention they more frequently started keeping the CPCC's number by their telephone or in the list of important numbers than parents in the control group, and this association remained significant when tested by generalized estimating equations for binary outcomes, after the adjustment for parents' characteristics (age, gender and educational level), and clustered by kindergartens (p < 0.001). This means parents acknowledged the CPCC as an adequate and accessible way for initial management of poisoning incidents.

Determination of Alt a 1 (Alternaria alternata) in poultry farms and a sawmill using ELISA.

Farm and sawmill workers are exposed to high levels of allergenic fungi, such as Alternaria alternata, which are associated with respiratory diseases and asthma. The aim of this study was to measure the concentration of Alt a 1, a major allergen of A. alternata, in indoor dust samples collected in poultry farms and a sawmill using a monoclonal antibody-based enzyme immunoassay. A total of 45 dust samples were collected in poultry farms (30) and the sawmill (15) in Zagreb County (Croatia). The Alt a 1 allergen was detected in all dust samples (100%) collected in three poultry farms. The levels of Alt a 1 were in the range of 0.1-14 microg/g, and the median value was 0.37 microg/g. About 86% of dust samples contained Alt a 1 in the range of 0.1-1.0 microg/g. In the sawmill, no detectable level of Alt a 1 was found (limit of detection =0.12 microg/g). This study has shown that occupational exposure to Alt a 1 allergen in poultry farms deserves monitoring.

Exposure to poultry dust and health effects in poultry workers: impact of mould and mite allergens.

PURPOSE: The aim of the study was to evaluate exposure to moulds and house dust mite Dermatophagoides pteronyssinus in poultry farms, and related health effects in poultry workers (PW). METHODS: The study involved 41 PW and 45 control office workers. Working environment was evaluated for D. pteronyssinus allergen (Der p 1), moulds and endotoxin. In workers, eye, skin and respiratory symptoms, ventilatory lung function, atopy markers (skin prick test to inhalatory allergens, total IgE) and specific IgG to moulds were assessed. RESULTS: Der p 1 levels ranged <0.1-3.3 microg/g, exposure to fungi was 4.9 x 10(3)-6.8 x 10(4) cfu/m(3), with prevailing Aspergillus, Penicillium and Mucor species, and endotoxin levels ranged 230-284 EU/m(3). In comparison to control subjects, significantly higher prevalence of work-related nose, asthma, eye and skin symptoms, and slight decline in ventilatory lung function was found in PW. PW had significantly higher prevalence of IgG antibodies to moulds comparing to controls (63 vs. 36%, respectively, P = 0.01), especially to Alternaria and Aspergillus species. The prevalence of atopy markers in PW was lower than in population-based studies. CONCLUSIONS: Hazardous levels of Der p 1, endotoxin and moulds were determined in poultry houses. High prevalence of work-related symptoms and IgG antibodies to moulds was found in PW. Healthy worker effect is proposed as an explanation of low atopy markers prevalence among PW.

Effects of Δ9-tetrahydrocannabinol on irinotecan-induced clinical effects in rats.

Because of the great interest for research on the potential use of cannabis preparations as co-medication for alleviation of toxic effects in cancer management, we investigated the influence of Δ9-tetrahydrocannabinol (Δ9-THC) to modulate irinotecan (CPT-11)-induced toxicity. Male Wistar rats were treated either with a single irinotecan intraperitoneal dose, 100 mg/kg body-weight (b.w.), or with irinotecan in combination with THC (7 mg/kg b.w., p.o., administered repeatedly for 1, 3 and 7 days). Serial blood samples were obtained up to seven days after dosing and were analyzed for complete blood count and biochemical parameters (liver enzymes, creatinine, inflammatory markers, and lipid status). Serial urine samples were collected in the first 24 h to monitor the time-course of THC metabolite 11-nor-9-carboxy-Δ9-THC (THC-COOH) excretion with concomitant irinotecan treatment or without. Both irinotecan and irinotecan + Δ9-THC administration caused moderate leukopenia but a greater decrease in leukocyte count was observed in the irinotecan + Δ9-THC treated compared to the single irinotecan suggesting higher cytotoxic effects in combined treatment. Irinotecan treatment induced elevation of aspartate aminotransferase (AST) in rats without diarrheal symptoms and without an increase in circulating pro-inflammatory mediators. Interestingly, the elevation of AST was not observed in the irinotecan + Δ9-THC group. The median creatinine-corrected urinary THC-COOH concentration was higher in the irinotecan + THC group compared to the THC-only group in a time-dependent manner, suggesting a possible early interaction between cannabinoids and irinotecan. Further studies are needed to investigate the role of cannabinoids particularly on hematological toxicity, irinotecan metabolism and their role as a possible modifiable factor among irinotecan-treated hosts.

Determination of mite allergens in house dust using the enzyme immunoassay.

The aim of this study was to determine the level of two major mite allergens Dermatophagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1) in 30 urban homes in Zagreb, Croatia, using the enzyme immunoassay with two monoclonal antibodies which has been established as the reference method for indoor allergen analysis. Dust samples were taken by vacuuming a carpeted area and collected on cellulose filters. The ranges of Der p 1 and Der f 1 were (0.1-12.5) microg g-1 (median 0.32 microg g-1) and (0.1-31.2) microg g-1 (median 0.35 microg g-1), respectively. Der p 1 and Der f 1 (>2 microg g-1) associated with increased risk of sensitization to mite allergens were found in approximately 16% homes for each allergen. The sum of allergen (Der p 1 + Der f 1) exceeded the lower threshold in 27% of homes. Analytical evaluation of the ELISA assay showed satisfactory results for precision (intra-assay CV <6.9%, inter-assay CV<13.3%), accuracy (91% to 93%), and sensitivity (2 ng mL-1). The ELISA assay for the measurement of dust mite allergens demonstrated very good analytical characteristics for routine laboratory use, and will provide the essential basis for our future studies of various indoor allergens.

Salivary sCD14 as a potential biomarker of dental caries activity in adults.

CD14 is a co-receptor involved in the recognition of Gram-negative and Gram-positive bacteria, the latter known to cause dental caries. The aim of this study was to determine whether soluble CD14 (sCD14) in saliva was associated with caries activity and the collection method from the saliva. The study included 55 participants aged 20 to 40 years, 30 with dental caries and 25 caries-free controls. We collected 110 saliva samples in total, 55 of resting saliva and 55 of mechanically stimulated saliva. Median levels of sCD14, measured with a matrix-matched enzyme-linked immunosorbent assay (ELISA), were higher in the caries-active than in the caries-free group in either resting (203.3 vs.167.9 ng mL-1; P<0.01) or stimulated saliva (201 vs.105.7 ng mL-1; P<0.01). The resting salivary flow rate was lower in the caries-active than caries-free group (0.61±0.42 vs. 0.98±0.52 mL min-1; P<0.01). Hyposalivation was observed only in the caries-active group (10 and 13 % in stimulated and resting saliva, respectively). Higher salivary sCD14 levels and secretion rates were clearly associated with dental caries and resting saliva. Future studies should focus on the clinical utility of salivary sCD14 as a potential biomarker and predictor of future caries events.

Soluble CD14 and total IgE in the serum of atopic and nonatopic adolescents in relation to environmental factors: a pilot study.

The CD14 receptor is expressed on the surfaces of monocytes, macrophages, and, to a lesser extent, of activated granulocytes and B lymphocytes (mCD14). It also exists in soluble form in the serum (sCD14), in which it binds microbial compounds and indoor allergens. The objectives of this study were to see whether serum sCD14 concentrations could be used as a marker of atopic disorders and to estimate the effects of environmental factors (tobacco smoke exposure, childhood residence in urban or rural areas, and having a pet) on sCD14 and IgE values. Mass fraction of sCD14 and total IgE were determined in the sera of atopic (N=53) and non-atopic (N=35) participants using the standard enzyme-linked immunosorbent assay. Exposure to pets and environmental tobacco smoke was estimated based on the International Study of Asthma and Allergies in Childhood questionnaire (ISAAC). Median sCD14 concentration was significantly lower in atopic than in non-atopic girls (3.49 vs. 3.83 µg mL(-1); p<0.010). The number of smokers at home positively correlated with the sCD14 level in atopics, and urban atopics had significantly lower sCD14 levels than rural atopics (3.47 vs. 3.92 µg mL(-1), p=0.028). Median total IgE concentration was significantly lower in atopic pet owners than in atopics with no pets (161 vs. 252 kIU L(-1); p=0.021). In conclusion, while sex and environmental factors might be involved in sCD14 expression, particularly in atopics, we found no correlation between sCD14 and total IgE concentrations. The usefulness of sCD14 as a marker of atopic disorders should be investigated further, particularly in relation to the severity of allergic disorders.

Arthropod allergens in urban homes.

Dust mites, cockroaches, and pets (cats, dogs) are common in homes worldwide, and many species are the source of potent allergens which cause allergic diseases. These diseases are influenced by genetic predisposition and environmental exposure. Generally, the levels of house dust mite (Der p 1 and Der f 1) and cockroach (Bla g 1, Bla g 2) allergens are used as markers of indoor exposure to arthropods.This article reviews the findings of allergens Der p 1, Der f 1, and Bla g 1 in randomly selected urban households in Zagreb (Croatia) measured from 2006 to 2010 and compares them with exposure to arthropod allergens in other countries. In short, house dust mite allergen levels in Croatian homes are low, but exposure is common; Der p 1 was found in 73 % and Der f 1 in 83 % of the households. By contrast, exposure to cockroach allergen Bla g 1 was both low and uncommon (13 %). Exposure to multiple allergens associated with sensitisation and asthma was not frequent in urban homes in Croatia. However, further studies should include monitoring of both arthropod and pet allergens in high-risk populations in inland and coastal Croatia. They should also investigate a complex dose-response relationship between exposure and sensitisation/asthma development, especially in early childhood.

Comparison of buffers for extraction of mite allergen der p 1 from dust.

Der p 1 is the main allergen of house dust mite Dermatophagoides pteronyssinus, which has routinely been detected in residential dust. However, the procedure for extracting Der p 1 from reservoir dust has not been well defined. The aim of this study was to compare Der p 1 mass fractions in dust extracts prepared using the following extraction buffers: phosphate (pH 7.4), borate (pH 8.0), and ammonium bicarbonate (pH 8.0), all with 0.05 % Tween 20. Twenty-eight dust samples were divided into three aliquots and each portion was extracted with one of the three buffers at room temperature. Der p 1 mass fractions were measured in a total of 84 dust extracts using the enzyme immunoassay (range: 0.1 µg g-1 to 7.53 µg g-1). Statistical methods including intraclass correlation showed a high agreement between Der p 1 mass fractions irrespective of the extracting medium. Our results suggest that all three buffers are suitable for the extraction of mite allergens and routine Der p 1 analysis in dust.

Biogenic amines in fish, fish products and shellfish: a review.

Fish, cephalopods and shellfish provide a healthy source of high-quality proteins, essential vitamins, minerals and polyunsaturated fatty acids. The beneficial effects of fish consumption on human health such as protection against coronary heart disease and certain cancer may be offset by fish decomposition and the formation of chemical contaminants such as biogenic amines. There are several toxicological effects of biogenic amines on humans, especially histamine. It is the causative agent of histamine or scombroid fish poisoning which is a significant public health problem. In individuals with diminished histamine detoxification, ingestion of even a low or moderate histamine- or tyramine-containing fish may lead to food intolerance. Biogenic amines such as putrescine, tyramine and cadaverine can potentiate histamine toxicity. Furthermore, dietary polyamine intake should be minimised in some cancer patients. Besides their potential toxicity, biogenic amines are used for the evaluation of hygienic quality of different marine and freshwater species. Spoilage pattern and biogenic amine formation are species specific. Histamine has been traditionally used as an indicator of the quality of histidine-rich fish (dark-muscle fish). On the other hand, putrescine and cadaverine are the most objective indicators of quality of histidine-poor fish (white-muscle fish), shellfish and fermented seafood products.

Indoor exposure to mould allergens.

Humid indoor environments may be colonised by allergenic filamentous microfungi (moulds), Aspergillus spp., Penicillium spp., Cladosporium spp., and Alternaria spp. in particular. Mould-induced respiratory diseases are a worldwide problem. In the last two decades, mould allergens and glucans have been used as markers of indoor exposure to moulds. Recently, mould allergens Alt a 1 (Alternaria alternata) and Asp f 1 (Aspergillus fumigatus) have been analysed in various environments (residential and occupational) with enzyme-linked immunosorbent assays, which use monoclonal or polyclonal antibodies. Household Alt a 1 and Asp f 1 levels were usually under the limit of the method detection. By contrast, higher levels of mould allergens were found in environments with high levels of bioaerosols such as poultry farms and sawmills. Data on allergen Alt a 1 and Asp f 1 levels in agricultural settings may provide information on possible colonisation of respective moulds and point out to mould-related diseases in occupants.

Bla g 1 allergen levels in Zagreb area household dust.

Cockroach allergy is a health problem in many parts of the world. In urban environments, indoor exposure to cockroach allergens involves a risk of asthma. The aim of this study was to measure the mass fraction of Bla g 1, a major allergen of the German cockroach (Blatella germanica) in 30 house samples, collected at random from Zagreb area households, Croatia. Dust samples were collected on cellulose filters by vacuuming living rooms floors. After extraction, Bla g 1 was detected using the commercial enzyme-linked immunosorbent assay (ELISA). Only four of the thirty households had detectable Bla g 1 levels, and only in one was its concentration higher than 2.0 U g(-1), the threshold associated with sensitisation. The Bla g 1 ELISA proved highly sensitive, with the detection limit of 0.12 U g(-1). The within- and between-assay imprecision was 8.9 % and 14.4 %, respectively, and accuracy 85 % to 120 %. Low Bla g 1 levels in the household dust support previously reported low prevalence of skin sensitisation to B. germanica among Zagreb residents. Further monitoring should reveal if there are differences in cockroach allergen exposure and sensitisation between households from other geographic areas in Croatia.

Determination of Aspergillus fumigatus allergen 1 in poultry farms using the enzyme immunoassay.

Poultry farms contain high levels of allergenic fungi, and Aspergillus spp. is the most common genus of moulds. Aspergillus fumigatus antigens are responsible for the development of several respiratory diseases including asthma. The aim of this study was to measure the mass fraction of Asp f 1, a major allergen of Asperillus fumigatus in 37 indoor dust samples collected from four poultry farms in a rural area of the Zagreb County (Croatia) using the enzyme-linked immunosorbent assay. More than 62 % of dust samples had detectable Asp f 1 levels (limit of detection 3.6 ng g(-1)). The overall mean Asp f 1 level was 17.9 ng g(-1) [range (3.8 to 72.4) ng g(-1)]. Satisfactory results were obtained for analytical within-run imprecision (6.7 %), between-run imprecision (10.5 %), and accuracy (91 % to 115 %). Microclimate parameters (air temperature, relative humidity, and velocity) were within the recommended ranges in all poultry farms. This study has shown that Asp f 1 settles on dust at poultry farms and that occupational exposure to this allergen deserves monitoring in livestock buildings.

Determination of biogenic amines and endotoxin in squid, musky octopus, Norway lobster, and mussel stored at room temperature.

Little research has been published on the indicators of spoilage in Mediterranean molluscan shellfish and crustaceans. Thus is why we studied changes in the concentrations of endotoxin and four biogenic amines (histamine, putrescine, tyramine and cadaverine) in European common squid (Loligo subulata, Lamarck, 1798), musky octopus (Eledone moschata, Lamarck, 1798), Norway lobster (Nephrops norvegicus, Linnaeus, 1758), and mussel (Mytilus galloprovincialis, Lamarck, 1819) from the Adriatic Sea stored at room temperature for 24 h. Endotoxin load in fresh squid, Norway lobster, and mussel (<1 EU mg-1) indicated good microbiological quality of raw samples. Biogenic amine index (as the sum of histamine, putrescine, tyramine, and cadaverine) correlated well with endotoxin load in squid (r=0.978, p<0.001) and musky octopus (r=0.874, p<0.01). A good correlation was also found between endotoxin and putrescine in Norway lobster (r=0.777, p<0.05). The highest endotoxin load was found in decomposed mussels and was associated with histamine alone. In conclusion, increase in biogenic amine levels is species-specific. Endotoxin analysis could be used for rapid assessment of microbiological quality of cephalopods and shellfish.

Endotoxin exposure assessment in wood-processing industry: airborne versus settled dust levels.

Wood processing is usually performed in environments with large amounts of endotoxin-rich bioaerosols that are associated with a variety of health effects. The aim of this preliminary study was to assess the relation between endotoxin levels in settled and airborne dust in wood-processing industry. Ten pairs of airborne and settled dust samples were collected in a sawmill and parquet manufacture of two wood-processing plants in Croatia. Endotoxin was assayed with a chromogenic end-point LAL (Limulus amebocyte lysate) method. The results showed that endotoxin levels in airborne respirable dust were above the proposed occupational exposure limit of 125 EU m(-3) and could be considered hazardous for the respiratory system. In settled dust they ranged between 229.7 EU mg(-1) and 604.3 EU mg(-1) and in airborne dust between 166.8 EU mg(-1) and 671.6 EU m(-3), but there was no significant correlation between them (Spearman's rho=0.358, P=0.310). This study points to sawmill settled dust as endotoxin reservoir and suggests that it may add to already high exposure to airborne endotoxins associated with wood processing. Investigations of the relation between settled and airborne endotoxin levels should be continued to better understand the sources and sites of endotoxin contamination in wood-processing industry.

Exhaled breath condensate pH in adult Croatian population without respiratory disorders: how healthy a population should be to provide normative data?

The aim of this study was to obtain preliminary exhaled breath condensate (EBC) pH values for healthy adult Croatian subjects, and to evaluate criteria for defining respiratory health of population providing normal EBC pH values in epidemiologic studies. In 109 adults without a history of lower airway symptoms (AS), four groups were described by narrowing the definition of "health" down to 1) without lower AS; 2) without lower and upper AS; 3) without AS, with normal FEV(1) and bronchial normoreactivity; 4) without AS, with normal FEV(1), bronchial normoreactivity, normal total IgE, and with negative skin prick test. Median EBC pH values did not differ between the groups (7.72, 7.73, 7.73, 7.73), but as health criteria got stricter, we observed a slight, nonsignificant increase in minimal pH values (6.95, 7.10, 7.20, 7.37). Median EBC pH values with interquartile range in the total sample (7.72; 7.63 to 7.76) were within the range previously reported by other authors. They did not differ regarding sex, smoking habit and atopic status, and were not associated with age, FEV(1) or total IgE. The non-significant trend in EBC pH observed with stricter criteria of respiratory health and atopic status indicates the need for further research on criteria for defining healthy population in a larger sample.

Endotoxin and biogenic amine levels in Atlantic mackerel (Scomber scombrus), sardine (Sardina pilchardus) and Mediterranean hake (Merluccius merluccius) stored at 22 degrees C.

Whole Atlantic mackerel (Scomber scombrus), sardine (Sardina pilchardus) and Mediterranean hake (Merluccius merluccius) from the Croatian Adriatic were stored at 22 degrees C and changes in histamine, putrescine, tyramine and cadaverine levels were monitored in relation to bacterial endotoxin. After 12 h, histamine levels in sardine were above the legal limit of 50 mg kg(-1), set by the US Food and Drug Administration, and an increase in putrescine content preceded the increase in histamine. After 24 h, histamine contents in mackerel and sardine reached 1090 +/- 101 and 577 +/- 275 mg kg(-1), respectively, which exceeded the toxic threshold of 500 mg kg(-1). At the same time, the putrescine content was also high in both fish (353-420 mg kg(-1)). The time-course of endotoxin production was similar in all fish species stored at 22 degrees C. A high correlation was found between endotoxin and histamine, and between endotoxin and putrescine in mackerel and sardine. On the other hand, high endotoxin levels in hake, after 24 h, were associated with the low histamine and putrescine content (40-60 mg kg(-1)).