Characterization of human iPSC-derived sensory neurons and their functional assessment using multi electrode array.

Sensory neurons are afferent neurons in sensory systems that convert stimuli and transmit information to the central nervous system as electrical signals. Primary afferent neurons that are affected by non-noxious and noxious stimuli are present in the dorsal root ganglia (DRG), and the DRG sensory neurons are used as an in vitro model of the nociceptive response. However, DRG derived from mouse or rat give a low yield of neurons, and they are difficult to culture. To help alleviate this problem, we characterized human induced pluripotent stem cell (hiPSC) derived sensory neurons. They can solve the problems of interspecies differences and supply stability. We investigated expressions of sensory neuron related proteins and genes, and drug responses by Multi-Electrode Array (MEA) to analyze the properties and functions of sensory neurons. They expressed nociceptor, mechanoreceptor and proprioceptor related genes and proteins. They constitute a heterogeneous population of their subclasses. We confirmed that they could respond to both noxious and non-noxious stimuli. We showed that histamine inhibitors reduced histamine-induced neuronal excitability. Furthermore, incubation with a ProTx-II and Nav1.7 inhibitor reduced the spontaneous neural activity in hiPSC-derived sensory neurons. Their responsiveness was different from each drug. We have demonstrated that hiPSC-derived sensory neurons combined with MEA are good candidates for drug discovery studies where DRG in vitro modeling is necessary.

Prescribing trends of proton pump inhibitors and histamine blockers among children in the United Kingdom (1998-2019): A population-based assessment.

PURPOSE: To describe the prescribing trends of proton pump inhibitors (PPIs) and H2 receptor antagonists (H2 RAs) among children with gastroesophageal reflux in the United Kingdom between 1998 and 2019. METHODS: We conducted a population-based retrospective cohort study using data from the Clinical Practice Research Datalink that included all children aged ≤18 years with a first ever diagnosis of gastroesophageal reflux between 1998 and 2019. Using negative binomial regression, we estimated crude and adjusted annual prescription rates per 1000 person-years and corresponding 95% confidence intervals (CIs) for PPIs and H2 RAs. We also assessed rate ratios of PPIs and H2 RAs prescription rates to examine changes in prescribing over time. RESULTS: Our cohort included 177 477 children with a first ever diagnosis of gastroesophageal reflux during the study period. The median age was 13 years (IQR: 1, 17) among children prescribed PPIs and 0.2 years (IQR: 0.1, 0.6) among those prescribed H2 RAs. The total prescription rate of all GERD drugs was 1468 prescriptions per 1000 person-years (PYs) (95% CI 1463-1472). Overall, PPIs had a higher prescription rate (815 per 1000 PYs, 95% CI 812-818) than H2 RAs (653 per 1000 PYs 95% CI 650-655). Sex- and age-adjusted rate ratios of 2019 versus 1998 demonstrated a 10% increase and a 76% decrease in the prescription rates of PPIs and H2 RAs, respectively. CONCLUSIONS: Prescription rates for PPIs increased, especially during the first half of the study period, while prescription rates for H2 RA decreased over time.

Evaluating biogenic amines and pH levels in farmed rainbow trout (Oncorhynchus mykiss) for freshness assessment during storage.

This study examined the production of eight key biogenic amines (methylamine, tryptamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) in 120 samples of farmed rainbow trout during various storage conditions, and determined any accompanying variations in pH. The main objective of this study was to identify which of the eight biogenic amines could be used as chemical markers to evaluate the quality of farmed rainbow trout. Histamine and tryptamine were not present in any of the samples, and the levels of cadaverine were inconsistent. The levels of putrescine significantly increased at 0 °C (by day 9), 2 °C (by day 8), and 4 °C (by day 4). Tyramine, spermidine, and spermine levels exhibited fluctuations but had a significant positive correlation with the levels of putrescine. The pH levels slightly increased from their initial values across all storage temperatures, with no significant variations observed. Based on the results, it can be concluded that putrescine may serve as an effective marker of the freshness of farmed rainbow trout during storage.

Assessment of the effect of glycation on the allergenicity of sesame proteins.

Sesame allergy is a growing concern worldwide. In this study, sesame proteins was glycated with glucose, galactose, lactose and sucrose respectively, and the allergenicity of different glycated sesame proteins were assessed by a comprehensive strategy, including simulated gastrointestinal digestion in vitro, a BALB/c mice model, a rat basophilic leukemia (RBL)-2H3 cell degranulation model and a serological experiment. Firstly, simulated gastrointestinal digestion in vitro showed that glycated sesame proteins were more easily to digest than raw sesame. Subsequently, the allergenicity of sesame proteins was assessed in vivo by detecting the allergic indexes of mice, and results showed that the levels of total immunoglobulin E (IgE) and histamine were reduced in glycated sesame proteins treated mice. Meanwhile, the Th2 cytokines (IL-4, IL-5, and IL-13) were downregulated significantly, demonstrating that sesame allergy was relieved in glycated sesame treated mice. Thirdly, the RBL-2H3 cell degranulation model results showed that the release of ß-hexosaminidase and histamine were decreased to different degrees in glycated sesame proteins treated groups. Notably, the monosaccharide glycated sesame proteins exhibited lower allergenicity both in vivo and in vitro. Furthermore, the study also analyzed the structure alteration of sesame proteins, and the results showed that the secondary structure of glycated sesame proteins were changed (the content of α-helix and ß-sheet were reduced), and the tertiary structure of sesame proteins after glycation modification was also changed (microenvironment around aromatic amino acids was altered). Besides, the surface hydrophobicity of glycated sesame proteins was also reduced except sucrose glycated sesame proteins. In conclusion, this study demonstrated that glycation reduced the allergenicity of sesame proteins effectively, especially glycation with monosaccharides, and the allergenicity reduction might be related to structural changes. The results will provide a new reference for developing hypoallergenic sesame products.

Multitargeting approaches to cognitive impairment: Synthesis of aryl-alkylpiperazines and assessment at cholinesterases, histamine H3 and dopamine D3 receptors.

Multitargeting ligands on enzymes and receptors may generate a profile for a potential treatment of cognitive impairment. Considering this, a set of 21 substituted aryl-alkyl-piperazines were designed, prepared and tested for their binding affinities at histamine H3 and dopamine D3 receptors (H3R and D3R, respectively) as well as acetyl- and butyrylcholinesterases (AChE/BChE) as potentially synergistic profile. Initial screening of the compounds at H3R and D3R was done at 1 or 10 µM and 100 µM at AChE and BChE assays. The most promising compounds were then evaluated in full concentration-response curves to estimate the Ki and IC50 values. Results showed that several compounds were ligands at H3R (n = 10), D3R (n = 6), AChE (n = 3), and BChE (n = 9). Compounds LINS05006 (Ki H3R 2.8 µM; D3R 0.7 µM; IC50 BChE 26.3 µM) and LINS05015 (Ki H3R 1.1 µM; D3R 3.1 µM; IC50 AChE 97.8 µM; BChE 43.7 µM) are highlighted since presented affinity in three different. These results suggest that methylpiperazine moiety led to balanced activity at all three classes of targets, and longer linker provided the best affinities. These compounds presented high ligand efficiency values (LE > 0.3) and may have adequate pharmacokinetic profile as suggested by calculated physicochemical properties.

Bioactive Amines in Wines. The Assessment of Quality Descriptors by Flow Injection Analysis with Tandem Mass Spectrometry.

Biogenic amines (BAs) occur in a wide variety of foodstuffs, mainly from the decomposition of proteins by the action of microorganisms. They are involved in several cellular functions but may become toxic when ingested in high amounts through the diet. In the case of oenological products, BAs are already present in low concentrations in must, and their levels rise dramatically during the fermentation processes. This paper proposes a rapid method for the determination of BAs in wines and related samples based on precolumn derivatization with dansyl chloride and further detection by flow injection analysis with tandem mass spectrometry. Some remarkable analytes such as putrescine, ethanolamine, histamine, and tyramine have been quantified in the samples. Concentrations obtained have shown interesting patterns, pointing out the role of BAs as quality descriptors. Furthermore, it has been found that the BA content also depends on the vinification practices, with malolactic fermentation being a significant step in the formation of BAs. From the point of view of health, concentrations found in the samples are, in general, below 10 mg L-1, so the consumption of these products does not represent any special concern. In conclusion, the proposed method results in a suitable approach for a fast screening of this family of bioactive compounds in wines to evaluate quality and health issues.

Prevalidation of the cAMP-PTx reporter assay for quantitative assessment of pertussis toxin activity.

Testing for inactivation of pertussis toxin and reversion to toxicity in aP vaccines has historically relied on the murine histamine sensitization test, that lacks mechanistic understanding, suffers from standardization problems and is associated with severe animal suffering. Though the regulatory requirements for in vivo testing of acellular pertussis (aP) vaccine products have been waived in Europe, it is still common practice globally. Easy and quantitative in vitro methods are therefore urgently needed. One of the alternatives under development is our reporter cell line - CHO-CRE cells - that carries a cAMP-reporter construct. After exposure to pertussis toxin, cells are stimulated with a low concentration of forskolin to allow detection of pertussis toxin dependent changes in intracellular cAMP levels. Here, the results of two prevalidation studies with purified pertussis toxin and pertussis toxin spiked aP vaccines are described that were performed according to the principles of the ICH Q2(R1) guidelines for a content assay. We confirmed the assay's specificity, accuracy, precision, linearity and range. The cAMP-PTx reporter assay allows for objective, reliable and quantitative assessment of pertussis toxin levels in aP vaccines and can thereby boost broad and global replacement of the histamine sensitization test.

Pharmacokinetic and pharmacodynamic assessment of histamine H3 receptor occupancy by enerisant: a human PET study with a novel H3 binding ligand, [11C]TASP457.

PURPOSE: Histamine H3 receptor antagonists and inverse agonists have been extensively developed to treat sleep-wake, neurocognitive, and allied disorders. However, potential adverse effects, including insomnia, hampered the clinical use of these drugs, possibly due to their persistent interaction with the target molecules. The purpose of the present study was to estimate the pharmacokinetics and pharmacodynamics of enerisant, a novel antagonist and inverse agonist for histamine H3 receptors. METHODS: To measure the histamine H3 receptor occupancy by enerisant, positron emission tomography studies using [11C]TASP457, a specific radioligand for histamine H3 receptors, were performed in 12 healthy men at baseline and at 2 h after oral administration of enerisant hydrochloride. For three of these subjects, two additional scans were performed at 6 and 26 h after the administration. Relationships between the receptor occupancy by enerisant and its dose and plasma concentrations were then analyzed. RESULTS: Administration of enerisant hydrochloride decreased the radioligand binding in a dose-dependent manner. The estimated receptor occupancy values at 2 h varied as a function of its dose or plasma concentration. The time course of the occupancy showed persistently high levels (> 85%) in the two subjects with higher doses (25 and 12.5 mg). The occupancy was also initially high at 2 h and 6 h with the lower dose of 5 mg, but it decreased to 69.7% at 26 h. CONCLUSION: The target engagement of enerisant was demonstrated in the brains of living human subjects. The occupancy of histamine H3 receptors by enerisant at 2 h can be predicted by applying the plasma concentration of enerisant to Hill's plot. The preliminary time-course investigation showed persistently high brain occupancy with high doses of enerisant despite the decreasing plasma concentration of the drug. Five milligrams or less dose would be appropriate for the treatment for narcolepsy with initially high occupancy allowing for effective treatment of narcolepsy, and then the occupancy level would be expected to decrease to a level to avoid this drug's unwanted side effect of insomnia at night, although further research is warranted to confirm the statement since the expected decrease is based on the finding in one subject. TRIAL REGISTRATION: This study was retrospectively registered with ClinicalTrials.gov (NCT04631276) on November 17, 2020.

A simpler potentiometric method for histamine assessment in blood sera.

Histamine intolerance results from a disequilibrium of accumulated histamine and the capacity for histamine degradation. An impaired histamine degradation based on reduced DAO activity and the resulting histamine excess may cause numerous symptoms mimicking an allergic reaction. For that, the determination of histamine in blood or in food products has great importance to identify risk factors. A new histamine-selective electrode is proposed using cucurbit[6]uril (CB[6]), as ionophore, in the analysis of biological samples. The selection of this smart supramolecular organic framework was based on its apparent stability constant of histamine-CB[6] (log ß) of 4.33. The optimized electrode based on a polymeric membrane (PVC) combines the histamine-selective ionophore with 2-nitrophenyl octyl ether as solvent mediator and potassium tetrakis(4-chlorophenyl)borate as anionic additive. Furthermore, multi-walled carbon nanotubes particles were included in the membrane composition to partly lower the detection limit of the method, while improving stability and lowering the response drift (± 4 mV). The electrodes showed a rapid response (≃ 13 s) in the pH operational range of 2.7-5.4, with a Nernstian slope of 30.9 ± 1.2 mV/dec, a detection limit of (3.00 ± 0.61) × 10-7 mol/L, and a lower limit of the linear range of (3.00 ± 0.00) × 10-7 mol/L. After miniaturization, the electrode was used as a detector in a sequential-injection lab-on-valve flow setup. The optimized flow conditions were achieved for sample injection volumes of 197 µL propelled towards the cell under detection, at a flow rate of 30 µL/s during 100 s, making the analysis of 30 samples per hour possible. The developed system was used to analyze spiked blood serum samples previously cleaned by using solid-phase extraction. The sample pretreatment of the serum samples using Oasis MCX cartridges showed outstanding efficiency for histamine determination. The recovery values for three different levels of histamine concentration (1 × 10-4 mol/L, 1 × 10-5 mol/L, and 1 × 10-6 mol/L) were (97 ± 6)%, (103 ± 1)%, and (118 ± 9)%, respectively, showing that this method was suitable for biological samples.

Towards a catheter-based impedimetric sensor for the assessment of intestinal histamine levels in IBS patients.

In this work, we report on the development of a catheter-based sensor designed for measuring the concentration of histamine in the human duodenum. Certain gut disorders, such as the irritable bowel syndrome (IBS), are associated with elevated levels of intestinal histamine due to chronic immune activation. As it is still impossible to determine histamine concentrations in vivo, a nasointestinal catheter with histamine-sensing capabilities has the potential to become a valuable diagnostic instrument. Regarding the sensing principle, we selected impedance spectroscopy using voltages that are compatible with intra-body applications with molecularly imprinted polymers (MIPs) as recognition elements. MIPs are synthetic receptors that offer the advantages of robustness, high specificity and selectivity for histamine as a target. In this specific case, the MIPs were synthesized from acryclic acid monomers, which guarantees a uniform binding capacity within the pH range of intestinal fluid. We have validated the catheter sensor on human intestinal liquids spiked with histamine in a testing setup that mimics the environment inside the duodenum. The dose-response curves show an analytical range between 5 and 200 nM of histamine, corresponding to physiologically normal conditions while higher concentrations correlate with disease. The key output signal of the sensor is the resistive component of the MIP-functionalized titanium electrodes as derived from the equivalent-circuit modelling of full-range impedance spectra. Future applications could be catheters tailored to cardiovascular, urological, gastrointestinal, and neurovascular applications. This, in combination with the versatility of the MIPs, will make this sensor platform a versatile diagnostic tool.

Assessment of the impact of sex in intensity, skin flares and central processing of histaminergic itch-A pilot study.

Itch is the commonest skin-related symptom, and sex differences are increasingly recognised as important determinants in stratified medicine, but only little is known about sex differences in itch. Questionnaire-based studies indicated that women perceive itch as more intensive and bothersome in comparison with men. However, data of studies using standardised itch models to objectify sex differences are scarce and inconsistent. To determine sex differences in intensity, skin flares and central processing of histaminergic itch, we compared 15 female and 15 male healthy subjects in a double-blinded, within-subject, placebo-controlled study using a histamine skin prick itch model (histamine 1% applied onto the volar forearm) and functional MRI. We found trends in higher mean itch intensity (0.58 VAS, CI 95% 0.004-1.19, P = .056) and maximum itch intensity (men 3.93 VAS ± 0.39 SD at 3 minutes, women 4.73 VAS ± 0.31 SD at 4 minutes, P = .073) in women paralleled by a trend in a stronger positive correlation between itch intensity and blood oxygen level-dependent (BOLD) activity in brain structures identified during itch in comparison with men (rs in women: .46, P = .08, rs in men: .07, P = .79). The erythema and wheal following histamine skin pricking were (non-significantly) larger in men, indicating that higher mean itch intensities on the right volar forearm in women may not be explained by more intense flares. The comparison of the activation patterns between the sexes revealed increased activity in men compared to women in the left middle temporal gyrus (temporooccipital part)/lateral occipital cortex. Thus, our findings indicate that histaminergic itch perception and central itch processing differ between the sexes under standardised conditions.

Quantitative assessment of skin swelling using optical coherence tomography.

BACKGROUND: Preclinical and clinical studies suggest that optical coherence tomography (OCT) is a useful tool to visualize inflammatory conditions. OBJECTIVE: The objective of this study was to evaluate the usefulness of combining OCT and various image processing techniques for quantitative assessment of histamine-induced tissue swelling. METHODS: Both time-domain and frequency-domain OCT were used on a mouse ear model. The ear thickness and volume before and after histamine challenge were determined from pixel locations in 2D scans and voxel number counting in 3D scans. Swelling kinetics was analyzed on 3D contour mapping. Microvessel network was visualized using speckle decorrelation analysis. RESULTS: OCT images showed that the thickness and volume changes were histamine dose and contact time dependent. The 3D mapping showed that the histamine-induced swelling spread slowly and directionally. OCT data indicated that microvessel opening and vessel dilation occurred prior to tissue swelling. CONCLUSION: OCT is a robust and quantitative non-invasive imaging tool for assessing skin swelling.

Survey and Exposure Assessment of Biogenic Amines in Fish Species Commonly Consumed in Korea.

Because of the increased awareness of the health benefits of fish, fish consumption has increased each year in several countries, including Korea. However, fish consumption is associated with acute toxicity owing to the presence of biogenic amines in rapidly spoiling fish. Several food safety agencies have established standards for acceptable histamine concentrations in some restrictive fish and fishery products; however, such standards are not available for other species. We aimed to generate data from biogenic amine monitoring to evaluate the safety of fish commonly consumed in Korea. We monitored the biogenic amine concentrations in 609 fish samples from 19 commonly consumed species. Of these 609 samples, several had amine concentrations higher than the maximums allowed. An age-specific exposure assessment based on human biogenic amine exposure per serving revealed that persons 1 to 3 years of age had the highest exposure to total biogenic amines, although no significant differences were found between the age groups analyzed. The analysis also revealed that the exposure in some fish species, such as Japanese jack mackerel, Konoshiro gizzard shad, and brown sole, exceeded the standard limits established in some countries. These results suggest that more fish species should be included to establish standards for exposure to various biogenic amines. Parameters such as age-specific consumption and data for populations with maximum consumption should be considered because the current standards are limited to histamine and do not account for the differences in histamine sensitivity associated with these variables. Our results provide important data on limits for biogenic amines in various fish species that could be used to minimize potential health risks.

Contamination and Prevalence of Histamine in Canned Tuna from Iran: A Systematic Review, Meta-Analysis, and Health Risk Assessment.

Histamine is one of the most important health issues associated with consumption of canned tuna because of possible allergic and anaphylactic reactions in consumers. Although the concentrations of histamine in tuna in Iran have been investigated in several studies, definitive conclusions are elusive. This study was undertaken as a systematic review and meta-analysis of the concentration and prevalence of histamine in Iranian canned tuna, and the related health risk was assessed. An extensive search of articles in the databases Scopus, PubMed, and Scientific Information Database resulted in 11 articles and a total of 693 samples for inclusion in this review. The minimum and maximum concentrations of histamine were determined as 8.59 ± 14.24 and 160.52 ± 87.59 mg kg−1, respectively. The mean concentration was calculated as 77.86 mg kg−1 (95% confidence interval [CI], 47.51 to 108.21 mg kg−1), which was lower than the 200 mg kg−1 recommended limit by the U.S. Food and Drug Administration (FDA). The mean prevalence of histamine was 9.19% (95%; CI, 6.88 to 11.5%). The 95% value of the target hazard quotient for adult consumers was calculated as 0.10. In all studies performed in Iran, the concentration of histamine in canned tuna was lower than FDA standard. Health risk assessment indicated low histamine risk (target hazard quotient < 1) for adults in Iran from consumption of canned tuna.

Silencing of H4R inhibits the production of IL-1ß through SAPK/JNK signaling in human mast cells.

CONTEXT: Mast cell (MC) activation through H4R releases various inflammatory mediators which are associated with allergic asthma. OBJECTIVES: To investigate the siRNA-mediated gene silencing effect of H4R on human mast cells (HMCs) functions and the activation of stress-activated protein kinases (SAPK)/jun amino-terminal kinases (JNK) signaling pathways for the release of ineterleukin-1ß (IL-1ß) in HMCs. MATERIALS AND METHODS: H4R expression was analyzed by RT-PCR and western blotting in human mast cell line-1 (HMC-1) cells and H4RsiRNA transfected cells. The effect of H4RsiRNA and H4R-antagonist on H4R mediated MC functions such as intracellular Ca2+ release, degranulation, IL-6 and IL-1ß release, and the activation SAPK/JNK signaling pathways were studied. HMC-1 cells were stimulated with 10 µM of histamine (His) and 4-methylhistamine (4-MH) and pretreated individually with H4R-antagonist JNJ7777120 (JNJ), histamine H1 receptor (H1R)-antagonist mepyramine, and signaling molecule inhibitors SP600125 (SP) and Bay117082. RESULTS: We found that the HMC-1 cells expressed H4R and H4RsiRNA treatment down regulated the H4R expression in HMC-1 cells. Both His and 4-MH induced the intracellular Ca2+ release and degranulation whereas; H4R siRNA and JNJ inhibited the effect. Furthermore, the activation of H4R caused the phosphorylation of SAPK/JNK pathways. H4R gene silencing and pretreatment with SP and JNJ decreased His and 4-MH induced phosphorylation of SAPK/JNK. We found that the activation of H4R caused the release of IL-1ß (124.22 pg/ml) and IL-6 (122.50 pg/ml) on HMC-1 cells. Whereas, SAPK/JNK inhibitor (68.36 pg/ml) inhibited the H4R mediated IL-1ß release. CONCLUSIONS: Taken together, the silencing of H4R inhibited the H4R mediated MC functions and SAPK/JNK phosphorylation. Furthermore, the H4R activation utilized SAPK/JNK signaling pathway for IL-1ß release in HMC-1 cells.

Assessment of the quality of refrigerated and frozen pork by multivariate exploratory techniques.

Pork loin and leg were evaluated 24h after slaughter and during refrigerated (5°C) and frozen storage for microbial counts, pH, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and bioactive amines. Spermine was the prevalent amine in fresh pork loin and leg, followed by spermidine and agmatine. During refrigerated storage, pH, TVB-N, mesophilic and psychrotrophic counts increased and no changes (p<0.05) were observed on polyamines; however putrescine, cadaverine and histamine were produced and accumulated throughout storage. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) for all parameters indicated a shelf life of 8days for both cuts, which was also coherent with safety regarding histamine levels. During frozen storage, there was no change on amines and pH, TVB-N decreased, and TBARS increased. None biogenic amine was produced. PCA and HCA were not able to classify frozen pork based on the analyzed parameters; however, a shelf life of 90days was suggested for the frozen cuts based on lipid oxidation.

Profiling wines in China for the biogenic amines: A nationwide survey and pharmacokinetic fate modelling.

Biogenic amines (BAs), a class of nitrogenous compounds that are frequently detected in wine, pose adverse effects to humans. However, with the largest red wine consumption in the world, little is known about national profiles correlating BAs in wines to toxicological/health risks in China. In this study, we conducted a nationwide survey of commercially available wines for the occurrence of BAs. Our sampling campaign covered >90% of wine brands (n = 456) in China in a three year span (2014-2016). The target BAs included tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine. In order to quantitatively characterize the potential risk and/or support regulatory decision-making, chronic and acute BA exposure scenarios were developed and simulated with a physiologically based pharmacokinetic model. The model described the fate and transport of BAs within human body using physical descriptions of relevant processes. These results provided baseline data that are needed for the risk assessment of dietary uptake of BAs and evaluating winemaking processes by food safety authorities.

El papel de los mastocitos en la evaluación de la respuesta inflamatoria posoperatoria, al implantar mallas protésicas para la reparación de defectos de la pared abdominal en biomodelos rata Wistar / The role of mast cells in the assessment of postoperative inflammatory response to implanting prosthetic mesh for the repair of abdominal wall defects in Wistar rats

Resumen Objetivo: El objetivo de este estudio fue evaluar el papel de los mastocitos en la respuesta inflamatoria posoperatoria tras el implante de mallas protésicas para la reparación de defectos de la pared abdominal en biomodelos rata Wistar. Materiales y Métodos: Se fabricó una malla de fibroma entretejiendo sus hilos. Se utilizaron 25 ratas Wistar macho adultas, a las cuales se les creó un defecto quirúrgico de 30 × 20 mm en la pared abdominal anterior. Este defecto anatómico fue posteriormente reparado con uno de los dos tipos de mallas previamente esterilizadas, las cuales fueron la malla de fibroína, y la malla comercial ultrapo monocryl prolene composite (Johnson & Johnson-Ethicon). A los 28 días después del procedimiento quirúrgico se sacrificaron los biomodelos y se extrajeron las muestras que posteriormente fueron tratadas con técnicas histoquímicas para su análisis histológico. Resultados: El estudio reportó adherencia a omento en los dos tipos de malla utilizadas, sin embargo, la malla comercial mostró adherencias de amplio espesor a colon, intestino delgado e hígado, incluyendo también al omento menor. Se encontró que la malla comercial presentaba mayor cantidad de mastocitos en las regiones estudiadas (dermis, perimisio, y la serosa visceral). Discusión: Estudios refieren que los mastocitos y sus productos como la histamina, la serotonina, entre otras juegan un papel clave en el control de la inflamación local, la cicatrización de heridas, adherencias y las reacciones a cuerpos extraños in vivo. Conclusión: Con base en la literatura consultada se puede concluir que el presente estudio es vanguardista en lo que respecta al posible papel que juegan los mastocitos en el proceso de reparación de defectos anatómicos de la pared abdominal.

Objective: The objective of this study was to evalúate the role of mast cells in the postoperative inflammatory response after implantation of prosthetic mesh to repair abdominal wall defects in Wistar rat. Materials and Methods: An abdominal wall defect (30 × 20 mm) was created in the anterior abdominal wall of 25 adult male Wistar rats. The anatomical defect was then repaired with one of the two type's meshes. Fibroin and monocryl ultrapo prolene meshes. Fibroin meshes were manufactured by weaving its threads, the polypropylene mesh was bought to Johnson & Johnson-Ethicon. After 28 days of implantation Wistar rats were sacrificed and the mesh with abdominal tissue was extracted. Subsequently the samples were treated with histochemical techniques for histological analysis. Results: The study reported adherence to omentum in both types of meshes used, however, the polypropylene mesh showed widely adhesions to colon, slight to intestine and liver, also in a very lower amount, adhesions to omentum. It was found that mast cells were presented in all the studied regions for the polypropylene mesh (dermis, perimysium, and visceral serosa). Discussion: Studies indicate that mast cells and their products such as histamine, seroto- nin, and others play a key role in controlling local inflammation, wound healing, adhesions, and reactions to foreign bodies in vivo. Conclusion: We can conclude that this study is a good step to show the possible role of mast cells in the abdominal wall repair process.

Assessment of the binding performance of histamine-imprinted microspheres by frontal analysis capillary electrophoresis.

Frontal analysis capillary electrophoresis was used to evaluate the binding performance of molecularly imprinted microspheres (MIM) toward its template histamine and analogs at pH 7, and compared to the high performance liquid chromatographic method. In both methods, batch binding was employed and the binding parameters were calculated from the measured concentration of unbound amine analytes and afforded comparable histamine equilibrium dissociation constants (Kd ∼ 0.4 mM). FACE was easily carried out at shorter binding equilibration time (i.e. 30 min) and without the need to separate the microspheres, circumventing laborious and, in the case of the system under study, inefficient sample filtration. It also allowed for competitive binding studies by virtue of its ability to distinctly separate intact microspheres and all tested amines which could not be resolved in HPLC. Kd 's for nonimprinted (control) microspheres (NIM) from FACE and HPLC were also comparable (∼ 0.6 mM) but at higher histamine concentrations, HPLC gave lower histamine binding. This discrepancy was attributed to inefficient filtration of the batch binding samples prior to HPLC analysis resulting in an over-estimation of the concentration of free histamine brought about by the presence of unfiltered histamine-bound microspheres.

Assessment of in vivo mast cell reactivity in patients with systemic mastocytosis.

BACKGROUND: Patients with systemic mastocytosis (SM) have clinical signs of mast cell (MC) activation and increased levels of MC mediators. It is unclear whether the increased mediator levels are caused by increased numbers of tissue MCs, or whether these cells in affected individuals have a hyperactive phenotype. OBJECTIVE: To determine reactivity of the skin and the airways to directly acting mediators and indirectly acting mast cell secretagogues in subjects with SM. METHODS: Skin reactivity to morphine and histamine, and airway responsiveness to mannitol and methacholine, was assessed in 15 patients with SM, 11 patients with allergic asthma (A) and 13 healthy controls (HC). Serum tryptase and urinary metabolites of the MC mediators histamine and prostaglandin D2 were measured, as well as ex vivo basophil histamine release. RESULTS: Mast cell mediators in the blood and urine were significantly higher in patients with SM than in HC and A controls. Responsiveness to local activation of skin MCs (by morphine) and airway MCs (by mannitol) was similar in SM and HC groups. Likewise, end-organ responsiveness in the skin to histamine, and in the airways to methacholine, was similar in all three subject groups. There was no evidence of increased basophil reactivity in SM patients. CONCLUSIONS AND CLINICAL RELEVANCE: Mast cells in the skin and airways of subjects with SM do not exhibit hyper-reactivity towards the MC-activating stimuli morphine and mannitol, respectively. Therefore, the highly elevated baseline levels of MC mediators in SM are most likely due to increased MC numbers, rather than altered MC responsiveness. The underlying mechanisms could involve leakage of MC mediators, or dysfunctions in mediator synthesis, storage and release. One clinical implication of our study is that there is no contraindication to perform skin tests using morphine in subjects with mastocytosis.