High Levels Of Histamine Research Articles

Regionalization of intestinal microbiota and metabolites in the small intestine of the Bactrian camel

IntroductionPeyer's patches (PPs) are crucial antigen-inductive sites of intestinal mucosal immunity. Prior research indicated that, in contrast to other ruminants, PPs in the small intestine of Bactrian camels are found in the duodenum, jejunum, and ileum and display polymorphism. Using this information, we analyzed the microbial and metabolic characteristics in various segments of the Bactrian camel's small intestine to further elucidate how the immune system varies across different regions. MethodsIn this study, the microbiota and metabolite of 36 intestinal mucosal samples, including duodenal (D-PPs), jejunal (J-PPs), and ileal PPs (I-PPs), were profiled for six Bactrian camels using 16S rRNA gene sequencing and liquid chromatography with tandem mass spectrometry (LC-MS/MS). To confirm meaningful associations, we conducted connection analyses on the significantly different objects identified in each group's results. ELISA was used to analyze the levels of IgA, IgG, and IgM in the same tissues. ResultsThe microbiota and metabolite profiles of J-PPs and I-PPs were found to be similar, whereas those of D-PPs were more distinct. In J-PPs and I-PPs, the dominant bacterial genera included Clostridium, Turicibacter, and Shigella. In contrast, D-PPs had a significant increase in the abundance of Prevotella, Fibrobacter, and Succinobacter. Regarding the metabolomics, D-PPs exhibited high levels of polypeptides, acetylcholine, and histamine. On the other hand, J-PPs and I-PPs were characterized by an enrichment of free amino acids, such as L-arginine, L-glutamic acid, and L-serine. These metabolic differences mainly involve amino acid production and metabolic processes. Furthermore, the distribution of intestinal immunoglobulins highlighted the specificity of D-PPs. Our results indicated that proinflammatory microbes and metabolites were significantly enriched in D-PPs. In contrast, J-PPs and I-PPs contained substances that more effectively enhance immune responses, as evidenced by the differential distribution of IgA, IgG, and IgM.DiscussionThe intestinal microenvironment of Bactrian camels displays distinct regional disparities, which we propose are associated with variations in immunological function throughout different segments of the small intestine. This study highlights the specific traits of the intestinal microbiota and metabolites in Bactrian camels, offering a valuable reference for understanding the relationship between regional intestinal immunity and the general health and disease of the host.

The Pathology and Blood Biochemistry of Juvenile Lates calcarifer on Diets Contaminated With Mycotoxins, Histamines and Rancid Fats-A Case Study.

Mycotoxins, originating from contaminated raw materials or suboptimal feed storage, are a growing concern in tropical aquaculture. Common fungi such as Aspergillus spp. and Fusarium spp. produce mycotoxins including aflatoxin, fumonisin, deoxynivalenol and zearalenone. High doses or prolonged exposure (weeks) to low doses of these mycotoxins (< 20 μg/kg) can depress growth, immunity, and cause mortality. This study investigated poor growth and low survival in juvenile Asian seabass, Lates calcarifer fed two different diets (FM40 and ABS3) for 5 weeks. Analysis of these diets revealed high peroxide values, multiple mycotoxins and high histamine levels. Fish fed the FM40 diet, which was contaminated with aflatoxin B1 (13.2 μg/kg), aflatoxin B2 (1.9 μg/kg), deoxynivalenol (29.5 μg/kg), alternariol (2.2 μg/kg), elevated peroxide value (45.91 mEq/kg), and histamine (129.51 mg/kg) developed mild bile duct hyperplasia, depressed total serum proteins (50.40 ± 10.06 g/L), markedly elevated blood potassium (8.2 ± 0.18 mmol/L), and heavy iron deposits in splenic melanomacrophage centres (Perl's stain) indicative of increased haemolysis. The presence of multiple cytotoxic mycotoxins in FM40 diet could explain the increased haemolysis and elevated blood potassium. In contrast, fish fed the ABS3 diet, which had high histamine levels (210.05 mg/kg), exhibited protein-losing nephropathy with multifocal fibrin plugs (Martius scarlet blue stain) indicating acute renal damage, and elevated blood calcium and phosphorus levels. Histamine is metabolised and excreted through the kidneys and known to induce renal arteriolar constriction, disrupt glomerular filtration barrier and increase permeability resulting in protein loss. This study shows that blood biochemistry and histopathology are useful diagnostic tools for assessing the impact of mycotoxins and histamines on fish health.

High histamine levels are associated with acute-on-chronic liver failure and liver-related death in patients with advanced chronic liver disease.

The role of histamine in advanced chronic liver disease (ACLD) is poorly understood. We investigated plasma histamine levels across ACLD stages and their prognostic value. We included patients with evidence of ACLD, defined by portal hypertension (hepatic venous pressure gradient [HVPG] ≥6 mmHg) and/or a liver stiffness measurement by transient elastography ≥10 kPa, who underwent HVPG measurement between 2017 and 2020. Acute-on-chronic liver failure (ACLF) and/or liver-related death were defined as composite endpoint. Of 251 patients, 82.5% had clinically significant portal hypertension (median HVPG: 17 mmHg [interquartile range (IQR) 12-21]) and 135 patients (53.8%) were decompensated at baseline. Median plasma histamine was 8.5 nmol/L (IQR: 6.4-11.5), 37.1% of patients showed elevated values (>9.9 nmol/L). Histamine levels did not differ significantly across Child-Turcotte-Pugh (CTP) stages nor strata of model for end-stage liver disease (MELD) or HVPG. Histamine levels correlated with markers of circulatory dysfunction (i.e. sodium, renin and aldosterone). During a median follow-up of 29.2 months, 68 patients developed ACLF or liver-related death. In univariate as well as in multivariate analysis (adjusting for age, sex, HVPG as well as either MELD, clinical stage, and serum albumin or CTP and serum sodium), elevated histamine levels remained associated with the composite endpoint. CTP-based multivariate model adjusted sub-distribution hazard ratio (asHR): 1.010 (95% CI: 1.004-1.021), p < .001; MELD-based multivariate model asHR: 1.030 (95% CI: 1.017-1.040), p < .001. High levels of histamine were linked to circulatory dysfunction in ACLD patients and independently associated with increased risks of ACLF or liver-related death. Further mechanistic studies on the link between histamine signalling and development of hyperdynamic circulation and ACLF are warranted.

Microstereolithography-fabricated microneedles for fluid sampling of histamine-contaminated tuna

A custom-designed microneedle sampling system was prepared using dynamic mask microstereolithography; this sampling system was used for determination of histamine content in fresh, histamine-spiked, and spoiled tuna flesh. Lateral flow (test strip) assays were successfully utilized in the microneedle sampling system to assess histamine content. Good agreement was noted between data obtained from the microneedle sampling system and a commercially available histamine detection kit. A discrepancy was noted in the results from the microneedle sampling system and the commercially available histamine detection kit at low (negative) levels of histamine. There was an improvement in the agreement between the microneedle sampling system and the commercially available histamine detection kit at higher histamine levels. The results, which showed an improvement in the test duration and the amount of reagent needed for histamine detection, indicate the promise of printed microneedle sampling systems for histamine detection in seafood samples and other types of food testing.

The Factors Influencing the Concentration of Histamine in Jarred Baby Foods Containing Fish, Considering Evaluation of Daily Histamine Intake

Histamine is one of the biogenic amines produced naturally in the human body, but also in foods, especially those rich in protein. Exogenous and endogenous histamine is subject to degradation in vivo, but in the case of sensitive groups, including children, these degradation processes may be less intense, resulting in adverse health effects from histamine excess. The aim of the study was to determine the histamine content in jarred baby foods containing fish, taking into account the selected product characteristics and storage conditions. The study included 140 meals with added fish, intended for infants and young children, from 5 leading manufacturers available in Poland. The infant meals were analyzed on the day of opening, after 24 h and 48 h of storage in the refrigerator and at room temperature. Histamine concentration was determined by ELISA. The THQ was calculated from the EDI values for histamine. Histamine was present in all analyzed baby foods. On the day of opening, the products had a lower content of this monoamine (Me = 2.59 mg/kg), which increased systematically during storage. Samples taken at 2 °C after 48 h showed an average histamine content of 4.4 mg/kg, while products stored at 22 °C at the same time showed a 1.8-fold higher concentration of this monoamine (Me = 7.9 mg/kg). Dishes containing tuna and sea fish had higher histamine levels on average than those containing pollock. The storage conditions of the children’s food had a significant effect on histamine concentration. The level of histamine in baby foods was related to the amount and type of fish in certain products. The results indicate the need for increased awareness of the risks associated with histamine, especially in a group of people with increased sensitivity to this amine, which may include infants and young children.

The effectiveness of garlic extracts on biogenic amine formation by foodborne pathogens and fish spoilage bacteria

SummaryImpacts of aqueous and ethanolic extracts of garlic were investigated in suppressing bacterial growth and biogenic amine (BA) formation by selected foodborne pathogens (Candida albicans, Salmonella paratyphi A, Escherichia coli and Staphylococcus aureus) and fish spoilage bacteria (Enterococcus faecalis, Photobacterium damselae and Pseudomonas luteola). The spread‐plate method was used to monitor bacterial growth in histidine decarboxylase broth (HDB), whereas the rapid high‐performance liquid chromatographic (HPLC) method was used for BA analysis. Bacterial growth and their ammonia and BA production were monitored using HDB. The results showed that bacterial growth on HDB was in the range from 9.13, for P. luteola, to 9.54 log CFU (colony‐forming units) mL−1, for S. aureus and C. albicans. The presence of garlic extracts in HDB resulted considerably in lowering bacterial growth and BA formation (P &lt; 0.05). The highest inhibitory activities of ethanolic and water garlic extracts were obtained for Gram‐positive S. aureus with 1.4 and 1.5 logarithmic reduction on bacterial growth, followed by Gram‐negative Salmonella Paratyphi A and E. coli. Application of garlic extracts, mainly ethanolic ones, showed a significant inhibitory effect on bacterial ammonia production, with 4‐100‐fold lower ammonia accumulation (P &lt; 0.05). Bacteria produced all tested BAs, mainly dopamine, agmatine and tryptamine. The highest levels of histamine and tyramine (61.99 and 36.45 mg L−1) were produced by S. aureus. In the presence of aqueous or ethanolic garlic extracts, putrescine production by E. faecalis was around 110‐fold lower than that of the control group. Results revealed that both garlic extracts are potent antimicrobials that can control the growth of foodborne pathogens and their harmful BA formation.

Untargeted metabolomics and metagenomics reveal signatures for intramammary ceftiofur treatment and lactation stage in the cattle hindgut.

The gut microbiota in cattle is essential for protein, energy, and vitamin production and hence, microbiota perturbations can affect cattle performance. This study evaluated the effect of intramammary (IMM) ceftiofur treatment and lactation stage on the functional gut microbiome and metabolome. Forty dairy cows were enrolled at dry-off. Half received IMM ceftiofur and a non-antibiotic teat sealant containing bismuth subnitrate (cases), while the other half received the teat sealant (controls). Fecal samples were collected before treatment at dry off, during the dry period (weeks 1 and 5) and the first week after calving (week 9). Shotgun metagenomic sequencing was applied to predict microbial metabolic pathways whereas untargeted metabolomics was used identify polar and nonpolar metabolites. Compared to controls, long-term changes were observed in the cows given ceftiofur, including a lower abundance of microbial pathways linked to energy production, amino acid biosynthesis, and other vital molecules. The metabolome of treated cows had elevated levels of stachyose, phosphatidylethanolamine diacylglycerol (PE-DAG), and inosine a week after the IMM ceftiofur application, indicating alterations in microbial fermentation, lipid metabolism, energy, and cellular signaling. Differences were also observed by sampling, with cows in late lactation having more diverse metabolic pathways and a unique metabolome containing higher levels of histamine and histamine-producing bacteria. These data illustrate how IMM ceftiofur treatment can alter the functionality of the hindgut metabolome and microbiome. Understanding how antibiotics and lactation stages, which are each characterized by unique diets and physiology, impact the function of resident microbes is critical to define normal gut function in dairy cattle.

Three cases of scombroid syndrome in Italy: clinical and preventive considerations.

Foodborne diseases are common sources of morbidity and mortality worldwide. Scombroid syndrome represents a particular condition since it is not directly related to the ingestion of spoiled food but is determined by high levels of histamine, a chemical mediator naturally produced within the human body under particular conditions. In these cases, histamine is formed as a result of the bacterial activity from histidine, an amino acid present at high levels in some fish species. The resulting symptomatology can range from mild symptoms such as headache and skin rash to more severe manifestations such as hypotension and coronary spasms. Reference regulations in Italy set maximum levels of histamine in food at 200 mg/kg. The cases described involve a family of three who, following the ingestion of a tuna dish, started to exhibit symptoms typical of an allergic reaction. In one case, hypotension, tachycardia, and electrocardiographic changes in the ST-tract suggestive of myocardial ischemia also appeared with negative myocardionecrosis enzyme dosage. All three cases experienced complete remission of symptoms in the absence of sequelae. Histamine concentrations in fish sampled three days later were 169 mg/kg. The cases described emphasize the importance of proper differential diagnosis as well as the importance of implementing specific controls in food hygiene.

A pilot study on the isolation and identification of histamine-producing bacteria from narrow barred Spanish mackerel and Japanese thread fin bream from Ukkadam fish market, Coimbatore, India

Consumption of marine fishes with high histamine levels due to improper storing leads to cause scombroid or histamine fish poisoning. In spoiled fishes, bacteria begin to break down the histidine into histamine by decarboxylation activity. Previous studies reported that black muscle fishes usually produce large amounts of histamine-producing bacteria (HPB). In this study, two white muscle fishes such as Scomberomorus commerson (Narrow-barred Spanish mackerel) and Nemipterus japonicus (Japanese threadfin bream) were chosen to detect the presence of histamine-producing bacteria (HPB). The fish samples were purchased from Ukkadam fish market in Coimbatore and examined for the occurrence of HPB on Niven agar. The isolated HPB on media were analyzed for identification based on their morphological characteristics, primary test, and biochemical test. Finally, 8 colonies were confirmed as the cause for histamine production of both fishes and among them, 5 belong to the family Enterobacteriaceae and others belong to the family Aeromonadaceae, Morganellaceae, and Enterococcaceae. Our study showed that the histamine-producing bacteria highly reported in dark-muscle fishes were also isolated from the chosen white-muscle fishes. Hence the presence of HPB indicates the improper maintenance of fish in retail fish markets. This considerable incidence of histamine-producing bacteria which on proliferation under suitable conditions may contribute to toxic histamine accumulation in the flesh of fishes.

Development of an Electrochemical Sensor for Histamine Detection, Based in the Formation of Complexes with Chelating Agents

Histamine(β-imidazolylethylamine) (His) is a biogenic amine. It is an important mediator involved invarious physiological and pathological processes, including neurotransmission and numerous brainfunctions, secretion of some hormones,regulation of gastrointestinal, circulatory functions, andinflammatory reactions. However, a high level of histamine in the human body causes an allergy-likesyndrome called histamine intolerance or histamine poisoning (toxic level 50 mg per 100 g ofproduct). The source of elevated histamine level is due to fermented foods, processed meat, andspoilage of the foodstuff, in particular seafood,due to uncontrolled microbial growth. Therefore,monitoring of histamine is a critical task for the food industry and food safety. Also, electrochemicalsensors have received extensive attention researchers in the development of rapid His detectionmethods due to their low cost, portability, higher sensitivity, and suitability for on-site screening. Thegeneral objective of this work is to develop an electrochemical sensor for the detection of Histaminebased on the modification of gold screen printed electrodes using L-cysteine (L-Cys) as a quelant agentfor the capture of our analite of interest. To study each step of the modification on the electrodesurface, electrochemical techniques were used: Electrochemical Impedance Spectroscopy (EIS) witha frequency of 50kHz and Cyclic Voltammetry(CV) with a window potential of -0.6 to 0.6 V and scanrate of 0.5V/s . As partial conclusions, the modification of the electrode with L-cys/Cu(II) wasdemonstrated by electrochemical methods. Thus, the developed sensor has the potential applicationfor Histamine detection

Insight into a natural novel histidine decarboxylase gene deletion in Enterobacter hormaechei RH3 from traditional Sichuan-style sausage.

Histamine (HIS) is primarily formed from decarboxylated histidine by certain bacteria with histidine decarboxylase (hdc) activity and is the most toxic biogenic amine. Hdc, which is encoded by the hdc gene, serves as a key enzyme that controls HIS production in bacteria. In this paper, we characterized the changes in microbial and biogenic amines content of traditional Sichuan-style sausage before and after storage and demonstrated that Enterobacteriaceae play an important role in the formation of HIS. To screen for Enterobacteriaceae with high levels of HIS production, we isolated strain RH3 which has a HIS production of 2.27mg/mL from sausages stored at 37°C for 180 days, using selective media and high-performance liquid chromatography. The strain RH3 can produce a high level of HIS after 28h of fermentation with a significant hysteresis. Analysis of the physicochemical factors revealed that RH3 still retained its ability to partially produce HIS in extreme environments with pH 3.5 and 10.0. In addition, RH3 exhibited excellent salt tolerance (6.0% NaCl and 1.0% NaNO2 ). Subsequently, RH3 was confirmed as Enterobacter hormaechei with hdc gene deletion by PCR, western blot, and whole-genome sequencing analysis. Furthermore, RH3 exhibited pathogenicity rate of 75.60% toward the organism, indicating that it was not a food-grade safe strain, and demonstrated a high level of conservation in intraspecific evolution. The results of this experiment provide a new reference for studying the mechanism of HIS formation in microorganisms. PRACTICAL APPLICATION: This study provides a new direction for investigating the mechanism of histamine (HIS) formation by microorganisms and provides new insights for further controlling HIS levels in meat products. Further research can control the key enzymes that form HIS to control HIS levels in food.

Oligomeric Proanthocyanidins Alleviate the Detrimental Effects of Dietary Histamine on Intestinal Health of Juvenile American Eels (Anguilla rostrata)

This study evaluated the oligomeric proanthocyanidins (OPC) on alleviating the detrimental effects in the intestine caused by dietary histamine in juvenile American eels (Anguilla rostrata). A total of 480 fish with a similar body weight of 10.84 ± 0.16 g were randomly divided into four groups, including the control group fed a basal diet, the HIS group fed a diet with a high level of histamine (534 mg/kg), the H + OPC I group fed the high histamine diet with 300 mg/kg OPC, and the H + OPC II group fed the high histamine diet with 600 mg/kg OPC. After the fish were fed the trial diets for 77 days, the intestinal samples were taken, and the related parameters were analyzed. Dietary 300 mg/kg or 600 mg/kg OPC could reverse the decreased activities of lipase, protease, and glutathione peroxidase and the level of total antioxidant capacity; the increased intestinal malondialdehyde and D-lactate acid levels and the activity of diamine oxidase in serum; and the decreased villus height caused by a high level of dietary histamine. There were no significant differences above all the indices between the H + OPC I group and the H + OPC II group. The higher relative abundances of potentially pathogenic bacteria were induced by the high level of dietary histamine. Dietary 300 mg/kg OPC might increase the relative abundance of the potential probiotics and inhibit the colonization of intestinal pathogenic bacteria. The intestinal health status of the H + OPC groups was similar to that of the control group. These results suggested that dietary 300 mg/kg OPC might alleviate the detrimental effects of dietary 534 mg/kg histamine on the intestine health of juvenile American eels by increasing the activity of digestive enzymes, improving the antioxidative potential and barrier function, and beneficially modulating the intestinal microbiota. Dietary 600 mg/kg OPC could not exert further improvement in growth performance and the intestinal health of juvenile American eels.

Successful treatment of JAK1-associated inflammatory disease

Gain-of-function variants of JAK1 drive a rare immune dysregulation syndrome associated with atopic dermatitis, allergy, and eosinophilia. This study sought to describe the clinical and immunological characteristics associated with a new gain-of-function variant of JAK1 and report the therapeutic efficacy of Janus kinase (JAK) inhibition. The investigators identified a family affected by JAK1-associated autoinflammatory disease and performed clinical assessment and immunological monitoring on 9 patients. JAK1 signaling was studied by flow and mass cytometry in patients' cells at basal state or after immune stimulation. Amolecular disease signature in the blood was studied at the transcriptomic level. Patients were treated with 1 of 2 JAK inhibitors: either baricitinib or upadacitinib. Clinical, cellular, and molecular response were evaluated over a 2-year period. Affected individuals displayed a syndromic disease with prominent allergy including atopic dermatitis, ichthyosis, arthralgia, chronic diarrhea, disseminated calcifying fibrous tumors, and elevated whole blood histamine levels. Avariant of JAK1 localized in the pseudokinase domain was identified in all 9 affected, tested patients. Hyper-phosphorylation of STAT3 was found in 5 of 6 patients tested. Treatment of patients' cells with baricitinib controlled most of the atypical hyper-phosphorylation of STAT3. Administration of baricitinib to patients led to rapid improvement of the disease in all adults and was associated with reduction of systemic inflammation. Patients with this new JAK1 gain-of-function pathogenic variant displayed very high levels of blood histamine and showed a variable combination of atopy with articular and gastrointestinal manifestations as well as calcifying fibrous tumors. The disease, which appears to be linked to STAT3 hyperactivation, was well controlled under treatment by JAK inhibitors in adult patients.

Cumulative effect of AOC1 gene variants on symptoms and pathological conditions in adult women with fibromyalgia: a pilot study.

Introduction: The amine oxidase copper-containing 1 (AOC1) gene encodes for the diamine oxidase (DAO) enzyme. DAO is an enzyme that catabolizes some molecules, including histamine, and is the degradative enzyme in the polyamine catabolic pathway that is active in intestinal mucosal cells. Variants of AOC1 are associated with reduced DAO activity, resulting in accumulation of high levels of histamine and causing a wide range of neurological, gastrointestinal, and epidermal disorders, which are present in people with fibromyalgia. This study aimed to evaluate the impact of four AOC1 gene variants, namely, rs10156191, rs1049742, rs1049793, and rs2052129, on fibromyalgia symptoms measured by the Fibromyalgia Impact Questionnaire (FIQ), such as sleep disorders, atopic dermatitis, migraine, gastrointestinal (GI) disorders, allergies, and intolerances, in adult women with fibromyalgia. Methods: The sample consisted of 100 unrelated women with fibromyalgia between 33 and 60years of age (48.48years ±7.35), whose were diagnosed by a rheumatologist based on symptoms such as pain, stiffness, and fatigue. Single-nucleotide polymorphisms (SNPs) of AOC1 were identified using oral mucosa samples collected following a standard hygiene protocol. DNA was extracted, and gene variants of interest were analyzed using multiplex single-nucleotide primer extension (SNPE). Clinical data were collected using the FIQ and a series of variables that quantified the intensity and frequency of the symptoms. Results: The minor allele frequencies of rs10156191, rs1049742, rs1049793, and rs2052129 were 31.5, 10, 32.5, and 27%, respectively. Each variant was found to be in Hardy-Weinberg equilibrium, but partial linkage disequilibrium between AOC1 SNPs is suspected. The results show that fibromyalgia symptoms measured using the FIQ tend to increase with the number of risk alleles and that the intensity of dry skin and low stool consistency may be associated with an increase in the number of these alleles. Conclusion: This study constitutes the first step in investigating associations between fibromyalgia symptoms and candidate variants of the AOC1 gene in DAO enzyme activity. Identification of reduced DAO activity may improve the quality of life and treatment of symptoms in fibromyalgia patients.

FRI-554 - High histamine levels associate with acute-on-chronic liver failure and liver-related death in patients with advanced chronic liver disease

FRI-554 - High histamine levels associate with acute-on-chronic liver failure and liver-related death in patients with advanced chronic liver disease

Study on the Sensitization and Antigenic Epitopes of Tropomyosin from Antarctic Krill (Euphausia superba).

Antarctic krill (Euphausia superba), a shrimp-like marine crustacean, has become a beneficial source of high-quality animal protein. Meanwhile, a special focus has been placed on its potential sensitization issue. In this study, a 35 kDa protein was purified and identified to be Antarctic krill tropomyosin (AkTM) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The purified TM showed a strong IgE-binding capacity to shrimp/crab-allergic patients' sera, indicating that TM is the primary allergen in Antarctic krill. Simulated gastrointestinal digestion revealed that the digestion stability of TM to pepsin was higher than that to trypsin. The strong degranulation triggered by TM in RBL-2H3 cells suggested that AkTM has a strong sensitization capacity. The TM-sensitized BALB/c mice displayed severe anaphylactic symptoms; high levels of TM-specific IgE, sIgG1, and histamine; and increased IL-4, indicating that AkTM could provoke IgE-mediated allergic reactions. Bioinformatics prediction, indirect competition ELISA, and mast cell degranulation assay were used to map the antigenic epitopes of AkTM. Finally, nine peptides of T43-58, T88-101, T111-125, T133-143, T144-155, T183-197, T223-236, T249-261, and T263-281 were identified as the linear epitopes of AkTM. The findings may help us develop efficient food processing techniques to reduce krill allergy and gain a deeper comprehension of the allergenicity of krill allergens.

Dietary Histamine Impairs the Digestive Physiology Function and Muscle Quality of Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂).

An 8-week feeding experiment was conducted to investigate the effect of dietary histamine on growth performance, digestive physiology function and muscle quality in a hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂). Seven isoproteic (50%) and isolipidic (11%) diets were prepared with various histamine inclusion levels of 0, 30, 60, 120, 240, 480 and 960 mg/kg in diets (actual contents were 72.33, 99.56, 138.60, 225.35, 404.12, 662.12 and 1245.38 mg/kg), respectively. Each diet was randomly assigned to triplicates of 30 juveniles (average body weight 14.78 g) per tank in a flow-through mariculture system. The increase in the dietary histamine level up to 1245.38 mg/kg made no significant difference on the growth rate and feed utilization of the grouper. However, the increased histamine content linearly decreased the activities of digestive enzymes, while no differences were observed in groups with low levels of histamine (≤404.12 mg/kg). Similarly, high levels of histamine (≥404.12 mg/kg) significantly damaged the gastric and intestinal mucosa, disrupted the intestinal tight junction structure, and raised the serum diamine oxidase activity and endotoxin level. Meanwhile, high doses of histamine (≥662.12 mg/kg) significantly reduced the activities of antioxidant enzymes, upregulated the relative expression of Kelch-like ECH-associated protein 1, and hardened and yellowed the dorsal muscle of grouper. These results showed that dietary histamine was detrimental to the digestive physiology function and muscle quality of the grouper, although it did compromise its growth performance.

Determination of biogenic amines in chicken, beef, and mutton by dansyl chloride microwave derivatization in Malaysia

In this study, an improved dansyl-chloride derivatization technique using a microwave synthesizer was used for the qualitative and quantitative analyses of biogenic amine in the fresh meat samples. The derivatization technique was optimized in terms of temperature, reaction time, and spinning speed. The derivatization method together with a validated reversed-phase HPLC-DAD method was used for the determination of biogenic amines in chicken, beef, and mutton sold in the wet market. The results of the analyses showed that tryptamine, putrescine, and histamine were generally detected in all the three types of meat. Higher levels of histamine were found in chicken and beef. However, low levels of histamine were observed in mutton. Tyramine was either detected low or moderate in all the three types of meat. The biogenic amines of the fresh meat sold in the wet market is generally higher than the reported values. The mechanisms of biogenic amines-dansyl-chloride formation were investigated and proposed. PRACTICAL APPLICATION: The biogenic amine derivatization method was improved. The improved derivatization method can be potentially used for various food products beside meats for routine biogenic amine analyses due to its fast analysis time and simplicity. High levels of biogenic amines were generally found in the meat sold in the wet markets. However, proper handling of the raw meat can reduce the risk of infection.

57 ISCHEMIC HEART SCOMBROID SYNDROME: FURTHER EVIDENCE FROM ALL OVER THE WORLD

Abstract Objective Scombroid syndrome (SS) is a long-standing poisoning illness caused by ingestion of improperly stored fish food (usually tuna fish) contaminated by Gram-negative bacteria. The main pathogenetic feature is toxicity by the high histamine (and/or other toxin) levels within the fish muscle. Scombroid syndrome accounts for approximately 5% of food toxicities at emergency department in the USA. It consists of gastrointestinal symptoms, sickness, at times (head) rash or flushing, peppery taste, hypotension, and other symptoms. Cardiovascular complications are infrequent, but acute coronary syndromes (ACSs) have been described in some patients on admission to hospital. We identified those cases as with ischemic heart scombroid syndrome (IHSS). Methods An accurate literature search for IHSS in case series and single reports, published as by the end of July 2022, was performed. Herein main clinical features are summarized. Results From 1997 to 2022, 18 studies were found describing 25 patients aged 42±15 years, 14 women (56%), likely to have IHSS. Countries of origin are depicted in the Figure nearby. Apart from typical clinical presentation of SS, chest pain, oppression and hypotension were complained by almost all patents. Symptoms and signs of ACS started 10 to 180 minutes from the meal. Four patients (mostly before 2015) required advanced life support or mechanical ventilation. Widespread ST-depression (first in the inferior leads) was the most frequently reported ECG feature (approximately in 90% of cases). Hospitalization was required for unstable patients or those admitted for coronary angiography. However, this latter was performed only in 10 cases (40%), and only in 3 (12%) a culprit lesion was identified and treated. Therapy consisted with antihistamine drugs, fluids and circulatory support, symptomatic drugs, and steroids in some cases. All patients were discharged from hospital with uneventful follow-up. Conclusions To date, 25 published cases of IHSS have been recognized, mostly from Italy, but reports are from all over the world. As in typical SS, myocardial ischemia begins shortly after raw or cocked (tuna) fish ingestion. However, due to unfamiliarity with the syndrome, diagnostic misinterpretation is possible. IHSS can be classified as a transient (usually benign) ACS, caused by coronary vasospasm in response to a nitroxide-mediated histamine-induced tissue hypoperfusion, in a similar way to type-I Kounis syndrome. Based on current knowledge, coronary angiography is mandatory in patients with a history of coronary artery disease and/or allergic diathesis, persistent symptoms or unresponsive to emergency treatment.

Intraoperative chlorhexidine-induced anaphylaxis suggesting an immunoglobulin-E-dependent mechanism indicated by basophil activation tests: two case reports

BackgroundAlthough chlorhexidine allergy has been shown to be mediated by immunoglobulin (Ig) E, few reports investigated the mechanism of chlorhexidine-induced anaphylaxis using basophil activation tests (BATs).Case presentationA 79-year-old man underwent cholecystectomy under general anesthesia. Anaphylaxis was diagnosed based on the clinical symptoms and high serum tryptase and histamine levels. Skin tests showed positive results only for chlorhexidine. Subsequently, BATs demonstrated that the causative agent was likely chlorhexidine. The inhibitory effect of wortmannin, an inhibitor of phosphoinositide 3-kinase, on basophil activation suggested an IgE-dependent mechanism underlying chlorhexidine-induced anaphylaxis.An 89-year-old man underwent inguinal hernioplasty under general anesthesia. Anaphylaxis was diagnosed based on the clinical symptoms and high serum tryptase and histamine levels. Skin tests and BATs with wortmannin were performed, showing similar results to case 1.ConclusionsBATs suggested an IgE-dependent mechanism for chlorhexidine-induced anaphylaxis and might be useful for investigating the mechanisms underlying drug-induced anaphylaxis.