High Histamine Research Articles

Biogenic amines and mycotoxins concentrations in baled silage from organic and conventional farms

ABSTRACT The aim of the current study was to investigate biogenic amines and mycotoxins concentrations in baled silage (mainly Poaceae family grasses) prepared in organic and conventional farms and to relate these parameters to fermentative parameters. The mean dry matter (DM) content was 364.10±93.31 and 424.70±95.93g/kg in the silage from organic and conventional farms respectively. The silage samples from organic farms had 17.00% higher (P≤ 0.05) tyramine (TY) than the silage from conventional farms. Conventional farm samples were characterized by 46.00% higher histamine (HIS) (P≤ 0.05), 9.80% higher putrescine (PUT) (P≤ 0.05), 17.30% higher cadaverine (CAD) (P≤ 0.05). Aflatoxins (AFL) (total) and zearalenone (ZEN), T-2/HT-2 concentrations were higher respectively 16.00% (P≤ 0.05) and 13.40% (P≤ 0.05), 1.80% (P≤ 0.05) in the silage prepared in organic farms. Deoxynivalenol (DON) concentration was higher 42.40% (P≤ 0.05) in silage from conventional farms. Volatile fatty acids (VFA), lactic acid, ethanol, pH and ammonia nitrogen showed that the silage samples from organic and conventional farms were of good quality. Our study suggests differences in biogenic amine formation or mycotoxins content in silage from organic and conventional farming, but, overall, the measured values are too low to be relevant for animal health. Furthermore, these differences might as well be due to the difference in dry matter content and plant maturity between the organic and conventional silage samples.

Histamine metabolism and transport are deranged in human keratinocytes in oral lichen planus.

Recent reports have indicated that nonimmune cells can produce low concentrations of histamine. This observation, together with the discovery of the high-affinity histamine H4 receptor (H4 R), has added additional layers of complexity to our understanding of histamine signalling. Human oral keratinocytes (HOKs) possess a uniform H4 R pattern, which is deranged in oral lichen planus (OLP). To investigate histamine metabolism and transport in HOKs of healthy controls and patients with OLP. Tissue sections and cultured primary HOKs were studied using immunostaining, quantitative real-time polymerase chain reaction and confocal microscopy. Histamine levels were analysed using high-performance liquid chromatography. l-histidine decarboxylase (HDC) and organic cation transporter (OCT)3 were increased in mRNA and protein levels in patients with OLP compared with controls. In contrast, histamine N-methyltransferase (HNMT) immunoreactivity was decreased in OLP. OCT1/OCT2 and diamine oxidase were not detectable in either tissue sections or in HOKs. Immunolocalization of HDC and OCT3 in HOKs revealed moderate-to-high expression within cytoplasm and cell boundaries. Stimulation with lipopolysaccharide (LPS) or interferon-γ upregulated HDC-gene transcript in HOKs, whereas this was downregulated with high histamine concentration and tumour necrosis factor-α. LPS induced a dose-dependent release of low histamine in HOKs, while high histamine concentration downregulated epithelial adhesion proteins. HOKs are histamine-producing cells. They release histamine via OCT3 channels in concentrations too low to activate the classical low-affinity H1 R and H2 R, but high enough to stimulate the high-affinity H4 R in autocrine and paracrine modes. The substantially deranged histamine metabolism and transport in OLP could, in part, contribute to the disease pathogenesis.

Combined Use of S. pombe and L. thermotolerans in Winemaking. Beneficial Effects Determined Through the Study of Wines' Analytical Characteristics.

The most common way to produce red wine is through the use of Saccharomyces cerevisiae strains for alcoholic fermentation and lactic acid bacteria for malolactic fermentation. This traditional winemaking methodology produces microbiologically stable red wines. However, under specific conditions off-flavours can occur, wine quality can suffer and human health problems are possible, especially after the second fermentation by the lactic acid bacteria. In warm countries, problems during the malolactic fermentation arise because of the high pH of the must, which makes it very difficult to properly control the process. Under such conditions, wines with high acetic acid and histamine concentrations are commonly produced. This study investigates a recent red wine-making technology that uses a combination of Lachancea thermotolerans and Schizosaccharomyces pombe as an alternative to the conventional malolactic fermentation. This work studies new parameters such as aroma compounds, amino acids, ethanol index and sensory evaluation. Schizosaccharomyces pombe totally consumes malic acid while Lachancea thermotolerans produces lactic acid, avoiding excessive deacidification of musts with low acidity in warm viticulture areas. This methodology also reduces the malolactic fermentation hazards in wines with low acidity. The main products are wines that contain less acetic acid, less biogenic amines and precursors and less ethyl carbamate precursors than the traditional wines produced via conventional fermentation techniques.

Label-Free Imaging of Histamine Mediated G Protein-Coupled Receptors Activation in Live Cells

G protein-coupled receptors (GPCRs) are the largest protein family for cell signal transduction, and most of them are crucial drug targets. Conventional label-free assays lack the spatial information to address the heterogeneous response from single cells after GPCRs activation. Here, we reported a GPCRs study in live cells using plasmonic-based electrochemical impedance microscopy. This label-free optical imaging platform is able to resolve responses from individual cells with subcellular resolution. Using this platform, we studied the histamine mediated GPCRs activation and revealed spatiotemporal heterogeneity of cellular downstream responses. Triphasic responses were observed from individual HeLa cells upon histamine stimulation. A quick peak P1 in less than 10 s was attributed to the GPCRs triggered calcium release. An inverted P2 phase within 1 min was attributed to the alternations of cell–matrix adhesion after the activation of Protein Kinase C (PKC). The main peak (P3) around 3–6 min after the histamine treatment was due to dynamic mass redistribution and showed a dose-dependent response with a half-maximal effective concentration (EC50) of 3.9 ± 1.2 μM. Heterogeneous P3 responses among individual cells were observed, particularly at high histamine concentration, indicating diverse histamine H1 receptor expression level in the cell population.

Quercetin ameliorates paclitaxel-induced neuropathic pain by stabilizing mast cells, and subsequently blocking PKCε-dependent activation of TRPV1

Severe painful sensory neuropathy often occurs during paclitaxel chemotherapy. Since paclitaxel can activate mast cell and basophils, whereas quercetin, a polyphenolic flavonoid contained in various plants, which can specifically inhibit histamine release as a mast cell stabilizer. In this study we explore whether quercetin could ameliorate paclitaxel-induced neuropathic pain and elucidated the underlying mechanisms. Quercetin inhibition on histamine release was validated in vitro by detecting histamine release from rat basophilic leukemia (RBL-2H3) cells stimulated with paclitaxel (10 μmol/L). In the in vivo experiments, rats and mice received quercetin (20, 40 mg·kg(-1)·d(-1)) for 40 and 12 d, respectively. Meanwhile, the animals were injected with paclitaxel (2 mg/kg, ip) four times on d 1, 3, 5 and 7. Heat hyperalgesia and mechanical allodynia were evaluated at the different time points. The animals were euthanized and spinal cords and dorsal root ganglions were harvested for analyzing PKCε and TRPV1 expression levels. The plasma histamine levels were assessed in rats on d 31. Pretreatment with quercetin (3, 10, 30 μmol/L) dose-dependently inhibited excessive histamine release from paclitaxel-stimulated RBL-2H3 cells in vitro, and quercetin administration significantly suppressed the high plasma histamine levels in paclitaxel-treated rats. Quercetin administration dose-dependently raised the thresholds for heat hyperalgesia and mechanical allodynia in paclitaxel-treated rats and mice. Furthermore, quercetin administration dose-dependently suppressed the increased expression levels of PKCε and TRPV1 in the spinal cords and DRGs of paclitaxel-treated rats and mice. Moreover, quercetin administration may inhibited the translocation of PKCε from the cytoplasm to the membrane in the spinal cord and DRG of paclitaxel-treated rats. Our results reveal the underlying mechanisms of paclitaxel-induced peripheral neuropathy and demonstrate the therapeutic potential of quercetin for treating this side effect.

Function-specific virtual screening for GPCR ligands using a combined scoring method

The ability of scoring functions to correctly select and rank docking poses of small molecules in protein binding sites is highly target dependent, which presents a challenge for structure-based drug discovery. Here we describe a virtual screening method that combines an energy-based docking scoring function with a molecular interaction fingerprint (IFP) to identify new ligands based on G protein-coupled receptor (GPCR) crystal structures. The consensus scoring method is prospectively evaluated by: 1) the discovery of chemically novel, fragment-like, high affinity histamine H1 receptor (H1R) antagonists/inverse agonists, 2) the selective structure-based identification of ß2-adrenoceptor (ß2R) agonists, and 3) the experimental validation and comparison of the combined and individual scoring approaches. Systematic retrospective virtual screening simulations allowed the definition of scoring cut-offs for the identification of H1R and ß2R ligands and the selection of an optimal ß-adrenoceptor crystal structure for the discrimination between ß2R agonists and antagonists. The consensus approach resulted in the experimental validation of 53% of the ß2R and 73% of the H1R virtual screening hits with up to nanomolar affinities and potencies. The selective identification of ß2R agonists shows the possibilities of structure-based prediction of GPCR ligand function by integrating protein-ligand binding mode information.

Fish Product–Borne Histamine Intoxication Outbreak and Survey of Imported Fish and Fish Products in Serbia

Histamine levels in fish and fish products are regarded as a primary criterion for food safety, considering the effects of histamine on human health. The aim of this research was to describe a case of massive histamine intoxication in Serbian children and to provide relevant information regarding the presence of histamine in imported marine fish and fish products available in the Serbian market. In January 2014, an incident of foodborne illness occurred in 28 children (aged 2 to 5 years) who consumed canned sardines in a kindergarten in Vojvodina province, northern Serbia. The diagnosis was established based on anamnestic data, epidemiological data, and clinical symptoms and confirmed by positive histamine finding in the incriminated sardines. Substantially high histamine levels (>300 mg/kg) were detected in seven of the nine examined units of these canned sardines. In addition, during an official veterinary border control from January 2013 to January 2015, 273 lots in total, including 2,457 fish and fishery product units, were analyzed using enzyme-linked immunosorbent assay. Even though only nine (3.29%) of all examined lots were declared as unsafe for human consumption, the presented case of histamine intoxication strongly suggests the importance of border inspection and comprehensive control of each imported lot.

High Cell Density Upregulates Calcium Oscillation by Increasing Calcium Store Content via Basal Mitogen-Activated Protein Kinase Activity.

Calcium releases of non-excitable cells are generally a combination of oscillatory and non-oscillatory patterns, and factors affecting the calcium dynamics are still to be determined. Here we report the influence of cell density on calcium increase patterns of clonal cell lines. The majority of HeLa cells seeded at 1.5 x 104/cm2 showed calcium oscillations in response to histamine and ATP, whereas cells seeded at 0.5 x 104/cm2 largely showed transient and sustained calcium increases. Cell density also affected the response of HEK293 cells to ATP in a similar manner. High cell density increased the basal activity of the mitogen-activated protein (MAP) kinase and calcium store content, and both calcium oscillation and calcium store content were down-regulated by a MAP kinase inhibitor, U0126. Thus, MAP kinase-mediated regulation of calcium store likely underlie the effect of cell density on calcium oscillation. Calcium increase patterns of HeLa cells were conserved at any histamine concentrations tested, whereas the overexpression of histamine H1 receptor, which robustly increased histamine-induced inositol phospholipid hydrolysis, converted calcium oscillations to sustained calcium increases only at high histamine concentrations. Thus, the consequence of modulating inositol phospholipid metabolism was distinct from that of changing cell density, suggesting the effect of cell density is not attributed to inositol phospholipid metabolism. Collectively, our results propose that calcium increase patterns of non-excitable cells reflect calcium store, which is regulated by the basal MAP kinase activity under the influence of cell density.

Determination of histamine in milkfish stick implicated in food-borne poisoning

An incident of food-borne poisoning causing illness in 37 victims due to ingestion of fried fish sticks occurred in September 2014, in Tainan city, southern Taiwan. Leftovers of the victims' fried fish sticks and 16 other raw fish stick samples from retail stores were collected and tested to determine the occurrence of histamine and histamine-forming bacteria. Two suspected fried fish samples contained 86.6 mg/100 g and 235.0 mg/100 g histamine; levels that are greater than the potential hazard action level (50 mg/100 g) in most illness cases. Given the allergy-like symptoms of the victims and the high histamine content in the suspected fried fish samples, this food-borne poisoning was strongly suspected to be caused by histamine intoxication. Moreover, the fish species of suspected samples was identified as milkfish (Chanos chanos), using polymerase chain reaction direct sequence analysis. In addition, four of the 16 commercial raw milkfish stick samples (25%) had histamine levels greater than the US Food & Drug Administration guideline of 5.0 mg/100 g for scombroid fish and/or products. Ten histamine-producing bacterial strains, capable of producing 373–1261 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine, were identified as Enterobacter aerogenes (4 strains), Enterobacter cloacae (1 strain), Morganella morganii (2 strains), Serratia marcescens (1 strain), Hafnia alvei (1 strain), and Raoultella orithinolytica (1 strain), by 16S ribosomal DNA sequencing with polymerase chain reaction amplification.

Survey of immuno-allergological ultra high dilution research

Experiments about basic research in Immuno-allergology reported by M. Bastide and B. Poitevin in Ultra High Dilution (1994) have been appraised from a 20 year perspective. The numerous experiments published mainly focus on immunological regulation, inflammatory process and basophil activation. They are analyzed according to one essential criterion: repeatability. The commentary reflects the research details made available in a recently published literature review, also published in French. The regulatory effect of high dilution of bursin on immune response has been observed in multiple experiments but not reproduced by independent teams. The immunomodulating effect of Thymulin has been confirmed in mice. Rhus toxicodendron has an anti-inflammatory activity on different models, from mother tincture (TM) to very high dilutions. The homeopathic complex Canova activates macrophages in vitro and in vivo, induces lymphocyte proliferation, and reduces the size of tumors and mortality of sarcoma-bearing mice. Some homeopathic medicines used in clinical inflammation modulate in vitro the neutrophil activation, with variability in the protocols used and in the medicines tested. In allergology, high dilution histamine has an inhibitory effect on basophil activation in multicenter trials and with independent teams, either with methods implying a change in basophil staining or with flow cytometry. However, high dilution histamine had no effect in some well-conducted experiments. The inhibitory effect of Apis mellifica has not been studied with the flow cytometry method, as well as the activation of basophil by anti-IgE high dilution, published in Nature. Despite considerable research activity in immuno-allergology and a great increase in the number of publications, there is still not in this domain a "gold standard" trial in basic research in homeopathy. The most studied system, the inhibitory effect of histamine high dilutions on basophil activation, requires clarifications of various factors, including individual sensitivity. For scientific and epistemological reasons, the same work should be carried out for independent reproduction of the experiments conducted with anti-IgE and Apis mel high dilution, in complement of the new axes of research in immunoallergology developed since 20 years.

Prevalence and Characterization of High Histamine-Producing Bacteria in Gulf of Mexico Fish Species

Recent developments in detection and enumeration of histamine-producing bacteria (HPB) have created powerful molecular-based tools to better understand the presence of spoilage bacteria and conditions, resulting in increased risk of scombrotoxin fish poisoning. We examined 235 scombrotoxin-forming fish from the Gulf of Mexico for the presence of high HPB. Photobacterium damselae subsp. damselae was the most prevalent HPB (49%), followed by Morganella morganii (14%), Enterobacter aerogenes (4%), and Raoultella planticola (3%). The growth characteristics and histamine production capabilities of the two most prevalent HPB were further examined. M. morganii and P. damselae had optimum growth at 35°C and 30 to 35°C and 0 to 2% and 1 to 3% NaCl, respectively. P. damselae produced significantly (P < 0.001) higher histamine than M. morganii in inoculated mahimahi and Spanish mackerel incubated at 30°C for 24 h, but histamine production was not significantly different between the two HPB in inoculated tuna, possibly due to differences in muscle composition and salt content. Results in this study showed that P. damselae was the most prevalent high HPB in Gulf of Mexico fish. In addition, previously reported results using the traditional Niven’s method may underreport the prevalence of P. damselae. Molecular-based methods should be used in addition to culture-based methods to enhance detection and enumeration of HPB.

Novel benzamide-based histamine h3 receptor antagonists: the identification of two candidates for clinical development.

The preclinical characterization of novel phenyl(piperazin-1-yl)methanones that are histamine H3 receptor antagonists is described. The compounds described are high affinity histamine H3 antagonists. Optimization of the physical properties of these histamine H3 antagonists led to the discovery of several promising lead compounds, and extensive preclinical profiling aided in the identification of compounds with optimal duration of action for wake promoting activity. This led to the discovery of two development candidates for Phase I and Phase II clinical trials.

Shelf-life of n-3 PUFA enriched frankfurters formulated with a konjac-based oil bulking agent

Frankfurters with improved-fat content were manufactured following two strategies: a) reduction of fat content by replacing pork backfat with konjac gel (KG); and b) reduction of fat/improvement of fatty acid profiles through partial substitution of pork backfat by an oil combination (olive, linseed and fish oils) stabilized in a -konjac matrix (oil bulking agent) (KG), in an oil-in-water emulsion (OWE), or a combination of both of these (KG and OWE).Their shelf-life characteristics were studied on the basis of nitrite, microbiological, biogenic amine profile and lipid oxidation analyses during chilling storage. Nitrite levels decreased over storage in all samples and were highest (P < 0.05) in the sample with OWE. No clear relationship was observed between microbiota and reformulation. High initial histamine levels were observed in frankfurters containing OWE and/or KG. Over chilling storage, histamine and tyramine increased the most, with the highest levels occurring in the samples containing the oil combination. Initial levels of lipid oxidation were lower in the control sample. The samples containing the oil combination presented similar lipid oxidation patterns over storage, with higher levels in F/OWE. No reformulation-dependent factor that might limit shelf-life was detected during storage.

Design and synthesis of a novel series of histamine H3 receptor antagonists through a scaffold hopping strategy

Lead compounds 5-fluoro-2-methyl-N-[2-methyl-4-(2-methyl-[1,3′]bipyrrolidinyl-1′-yl)-phenyl]-benzamide (1), tetrahydro-pyran-4-carboxylic acid [((2S,3′S)-2-methyl-[1,3′]bipyrrolidinyl-1′-yl)-phenyl]-amide (2), and 3,5-dimethyl-isoxazole-4-carboxylic acid [((2S,3′S)-2-methyl-[1,3′]bipyrrolidinyl-1′-yl)-phenyl]-amide (3) discovered in our laboratory, displayed high histamine H3 receptor (H3R) affinity, good selectivity and weak human Ether-à-go-go-Related Gene (hERG) channel affinity with desirable overall physico-chemical and pharmacokinetic (PK) profiles. Herein, we describe the design and synthesis of a novel series of H3R antagonists utilizing a scaffold hopping strategy. Further structure–activity relationship (SAR) studies of the series culminated in the identification of ((2S,3′S)-2-methyl-[1,3′]bipyrrolidinyl-1′-yl)-naphthalene-2-carboxylic acid (tetrahydro-pyran-4-yl)-amide (4c) and -[4-((2S,3′S)-2-methyl-[1,3′]bipyrrolidinyl-1′-yl)-phenyl]-N-(tetrahydro-pyran-4-yl)-acetamide (4d), which exhibited good H3R affinity in vitro, good selectivity, and desirable PK properties. Compounds 4c and 4d were also assessed in cardiac safety experiments. In particular, the effects of the compounds on action potentials recorded from ventricular myocytes isolated from guinea pigs were used to screen compounds that not only displayed a low affinity towards hERG channel, but also had lower interference with other cardiac ion channels. Compound 4c did not alter the major parameters in this model system at ⩽10μM, and no significant induction of any major haemodynamic effect when intravenously administered at 3mg/kg dose to anaesthetized mongrel dogs. Compound 4c is a new promising lead as orally potent and selective H3R antagonist belonging to a distinct structural class.

Biologically active amines in fermented and non-fermented commercial soybean products from the Spanish market

Biologically active amines were determined in commercial soybean products. The antioxidant polyamines were found in both non-fermented and fermented soybean products. Natto and tempeh showed the highest content of polyamines (75–124 and 11–24mg/kg of spermidine and spermine, respectively). On the other hand, the bacterial-related biogenic amines, tyramine, histamine, tryptamine and β-phenylethylamine, were detected in practically all fermented products with a high variability. The highest contents were found in sufu, tamari and soybean paste. Extremely high tyramine and histamine contents, 1700 and 700mg/kg, respectively, found in some sufu samples could be unhealthy. However, biogenic amines observed in the other soybean products should not be a risk for healthy consumers. However, individuals who take monoamine and diamine oxidase inhibitors drugs should be strongly recommended to avoid this kind of products in order to suffer no adverse health effects. These biogenic amines were not detected in non-fermented soybean products.

Histamine H4 receptor in oral lichen planus.

Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P= 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts. Healthy oral epithelial cells are equipped with H4 R, which displays a uniform staining pattern in a MC-independent fashion. In contrast, in OLP, increased numbers of activated MCs associate with increasing loss of epithelial H4 R. Cell culture experiments suggest a rapid H4 R stimulation-dependent receptor internalization and a slow cytokine-driven decrease in H4 R synthesis. H4 R may be involved in the maintenance of healthy oral mucosa. In OLP, this maintenance might be impaired by MC degranulation and inflammatory cytokines.

ABSTRACT 745

Background and aims: Dystonia is a neurologic movement disorder, in which causes involuntary muscle contractions and abnormal postures. We reported a case of generalized form of dystonia after taking albendazole and cetirizine. Only one case with albendazole and two cases with cetirizine induced dystonia were previously reported. Methods: Case: A three years and six months old boy who rapidly developed lateral flexion of neck, extension of forearms, adduction and flexion of arms was presented to Pediatric Emergency Department. According to the history, he received only single dose of albendazole and cetirizine 20 hours ago, because of a probable worm infection. Except dystonia, examination was normal. He was managed as dystonia based on history and signs. His symptoms resolved after six hours of intramuscular biperiden treatment. On follow-up visit at the 24th hour of onset, the patient had no complaint. He was thought to be drug-induced dystonia caused by albendazole and/or cetirizine. Conclusions: Antiemetics, antidepressants, dopamine-blocking agents and antipsychotics are the best-known cause of drug induced dystonia. Cetirizine is a high selective histamine H1 receptor antagonist which has dopamine receptor blocking properties in susceptible individuals and may cause dystonic movements. Albendazole affects the cell by inhibiting tubulin polymerization. Two drugs separately or both may be responsible from dystonia in our patient. The metabolic effects of cetirizine are longer acting than effect of albendazole. The patient developed dystonia in nearly 20 hours after taking these two drugs. Therefore, we speculated that in this case cetirizine may lead to dystonia because of its long acting.

Estudio de la secreción gástrica en la cirrosis hepática

Se estudia la secreción gástrica con la máxima estimulación histamínica en un grupo de 31 pacientes con cirrosis hepática, comparando los resultados con los valores encontrados en un grupo de personas normales llamados controles y en otro grupo con úlcera duodenal. Los pacientes con cirrosis hepática secretan muy poco ácido clorhídrico, tanto en condiciones basales como después de la máxima estimulación histamínica, siendo el DAB 1.77 ± 1.66 mEq de HCl total, y el DAM 7.13 ± 5.35 mEq. Esta hiposecreción gástrica no depende del grado de descompensación hepática. Es posible que se deba a un reducido número de células parietales, por una gastritis crónica atrófica consecuente a la acción tóxica del alcohol, de la malnutrición o de algún otro factor. Sería interesante estudiar la secreción gástrica en alcohólicos sin cirrosis y en malnutridos sin cirrosis, para explicar Este hallazgo. En 24 cirróticos sometidos a estudio radio lógico digestivo alto se encontró 20% con úlcera duodena!, incidencia mayor que la existente para la población general (10). La secreción gástrica en los cirróticos con úlcera duodenal fue más alta que en los sin úlcera, y estadísticamente semejante a la secreción de los controles y ulcerosos duodenales. El DAB fue 9.51 ± 6.17 y el DAM: 29.23 ± 4.69 mEq de HCl total. Es necesario ampliar el estudio con mayor número de casos pera obtener conclusiones más definitivas.

Emerging Approach: Reduce Histamine Poisoning with Diamine Oxidase

Rihaakuru is a cooked fish paste from the Maldives, consumed as a condiment with rice and other food. One of our studies confirmed that Rihaakuru contained up to 10 different biogenic amines, with histamine in excess of 500 ppm (n = 28). This may cause histamine poisoning, with symptoms such as skin rashes, vomiting and fever, thus making it a food security issue in the Maldives. Another study by us developed a regression model that predicted the rate and amount of histamine removal by diamine oxidase (DAO) under varied pH and salt concentrations in the tuna soup used to manufacture Rihaakuru. Based on the results of these studies, a conceptual design in producing histamine-free Rihaakuru is described in this paper. This conceptual design could be used as a guideline in the actual production of histamine-free Rihaakuru. Histamine-free Rihaakuru could be a potential export containing high protein and omega-3. Practical Applications Rihaakuru is a fish paste that is rich in protein, minerals and contains omega 3. However, Rihaakuru can contain more than 500 ppm histamine that may cause food poisoning. This histamine originates from poor quality raw fish used to manufacture this product. The manufacture of Rihaakuru is seen as a way of using poor quality fish. Rihaakuru is generally stable in terms of bacterial deterioration and the only issue is the high histamine level. This research demonstrated on a novel method to prevent histamine food poisoning using diamine oxidase, to degrade the histamine in the fish soup during the manufacture of Rihaakuru. This enables the manufacture of histamine free-Rihaakuru and has the potential to be applied to other foods containing histamine.

Spontaneous basophil responses in food-allergic children are transferable by plasma and are IgE-dependent

Early studies showed that up to 80% of children with food allergy demonstrate high spontaneous basophil histamine release (SBHR).1 An association with IgE was suggested because basophils from food-allergic (FA) children additionally released histamine to the IgE-dependent histamine-releasing factor.2 However, the exact mechanism(s) responsible for SBHR, including the dependency for IgE, remains poorly understood. We recently reported that SBHR significantly decreased in children undergoing sublingual immunotherapy/oral immunotherapy (SLIT/OIT) for cow's milk allergy,3 prompting further investigations of this response and other markers of basophil hyperresponsiveness.