Tissue Residues Research Articles

Abstract 5451: Multiplex immunofluorescence for cancer research

Abstract Multiplex Immunofluorescence (M-IF) is a technique where multiple antibodies are visualized using unique fluorophores on the same slide. Thus, instead of employing panels of separately stained IHC slides that only reveal regional localization, it enables direct visualization of numerous proteins of interest on the same cell. This enables researchers and clinicians to comprehend precise interactions taking place at the cellular level in their tissue. The challenge of figuring out how to individually link markers with fluorophores without incurring cross contamination has hindered the development of M-IF assays. The first traditional approach was to ensure each marker was generated from a unique host species, and then use secondary antibodies against those host species conjugated to unique fluorophores. As a result, the unique host species that an antibody could be generated in were exhausted forcing the researchers to reach into exotic species. The second generation of technologies attempted to temporally solve this problem by sequentially staining the markers and then stripping off the antibody in between steps; preserving the fluorophores. This system leveraged the interaction of tyramide attached to a fluorophore and its affinity for tyrosine residues in tissue to form a stronger bond then the antibody to the tissue to endure the harsh striping step. This allowed the usage of multiple antibodies from the same host species but added antigen sheltering as the confounding variable due to crowding and exhaustion of antigenic sites. The latest generation technology we are using attempts to solve this linkage problem with DNA barcoding. A lock and key mechanism wherein the primary antibody is pre-conjugated with a unique barcode and the fluorophore with a corresponding inverse barcode. In this technique the primary antibodies can be applied as a cocktail in parallel to the tissue with the dna based linkage easily and gently broken when necessary. We then took this novel technique and applied it in a shotgun approach using Tissue Microarrays (TMAs) to screen against dozens of cores from breast, endometrial, carcinoma and melanoma cases. We then use Inform software to algorithmically categorize each cell and R-Studio to statically prove a significant coefficient of variation. This creates the ability to build panels for signatures that answer key research questions like “Where are the immune cells in the tissue microenvironment” and “is the tumor hot or cold? Activated, exhausted or proliferating?”. This abstract contrasts the operation of the new technology with the earlier approaches and will demonstrate how artificial intelligence-assisted algorithms can analyze and produce statistically significant datasets for cancer researchers. Citation Format: Patrick Savickas, Sharwari Phanse. Multiplex immunofluorescence for cancer research. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5451.

Assessment of the Level of Pesticide Contamination in Amphibians from Cocoa Plantations at Ojo Camp-Ugboke, Southern Nigeria

Amphibian skin is extremely permeable to environmental contaminants and their health is inextricably linked to environmental health. Hence the objective of this study was to evaluate the level of pesticide contamination in amphibian tissues and their environment (soil and sediment) at Ojo Camp-Ugboke cocoa plantations in Edo State, southern Nigeria using HP 5890 series gas chromatography system coupled with an Electron Capture Detector (ECD). Data obtained showed that thirteen organochlorine pesticides, one triazine herbicide, carbamate, and organophosphate were found in high concentrations. All pesticides components were detected in amphibian tissues, most with higher concentrations than other samples. The high permeability of amphibian skin is responsible for the detected in-tissue concentrations. Pesticide residues in amphibian tissues are not only harmful to their health, but also pose a health risk to those who consume amphibian meat as a delicacy. Local farmers' unabated/unregulated use of pesticides may contribute in amphibian population decline. For a healthier environment, it is best to increase public awareness while also supporting routine monitoring and regulation by relevant agencies.

Assessment of Heavy Metals Contamination and Antimicrobial Drugs Residue in Broiler Edible Tissues in Bangladesh.

There are substantial public health consequences when hazardous heavy metal contaminants and antimicrobial drug residues are present in broiler edible tissues. This study aimed to assess the concentration of antimicrobial drugs and heavy metals residues in broiler meat, bones and edible composites (combinations of liver, kidney and gizzard). Samples were collected from different types of broiler farms, broiler wet meat markets and supermarkets, covering all five divisions of Bangladesh. The antimicrobial drug and heavy metal residues were analyzed by uHPLC and ICP-MS, respectively. In addition, a cross-sectional survey was conducted among broiler meat consumers in the study areas to evaluate their attitude towards the consumption of broiler meat. The survey clearly stated that broiler meat consumers in Bangladesh have a negative attitude toward the consumption of broiler meat, although all respondents reported to eat broiler meat regularly. The antibiotic with the highest prevalence of residues in broiler edible tissues was oxytetracycline, followed by doxycycline, sulphadiazine and chloramphenicol. On the other hand, all collected broiler edible tissues contained chromium and lead, followed by arsenic. The fact of the matter is that the antimicrobial drugs and heavy metals residues were found to be below the maximum residue limit (MRL), except for the lead content. In addition, the broiler meat samples from supermarkets had lower levels of antimicrobial drugs and heavy metals residue compared to the broiler meat collected from various types of farms and broiler wet meat markets. Irrespective of the source, broiler meat was found to contain antimicrobial drugs and heavy metals residues below the MRL, except for lead, suggesting that broiler meat is safe for human consumption. Therefore, raising public awareness regarding misconceptions about broiler meat consumption among consumers would be warranted.

Long-Term Degradation Assessment of a Polyurethane-Based Surgical Adhesive—Assessment and Critical Consideration of Preclinical In Vitro and In Vivo Testing

Tissue adhesives constitute a great possibility to improve conventional wound closure. In contrast to sutures, they enable nearly immediate hemostasis and can prevent fluid or air leaks. In the present study, a poly(ester)urethane-based adhesive was investigated which already proved to be suitable for different indications, such as reinforcing vascular anastomosis and sealing liver tissue. Using in vitro and in vivo setups, the degradation of the adhesives was monitored over a period of up to 2 years, to evaluate long-term biocompatibility and determine degradation kinetics. For the first time, the complete degradation of the adhesive was documented. In subcutaneous locations, tissue residues were found after 12 months and in intramuscular locations, tissue degradation was complete after about 6 months. A detailed histological evaluation of the local tissue reaction revealed good biocompatibility throughout the different degradation stages. After full degradation, complete remodeling to physiological tissue was observed at the implant locations. In addition, this study critically discusses common issues related to the assessment of biomaterial degradation kinetics in the context of medical device certification. This work highlighted the importance and encouraged the implementation of biologically relevant in vitro degradation models to replace animal studies or at least reduce the number of animals in preclinical testing prior to clinical studies. Moreover, the suitability of frequently used implantation studies based on ISO 10993-6 at standard locations was critically discussed, especially in light of the associated lack of reliable predictions for degradation kinetics at the clinically relevant site of implantation.

Analysis of Transfer of Tiamulin to Animal Tissue after Oral Administration: An Important Factor for Ensuring Food Safety and Environmental Protection.

The administration of veterinary medicinal products containing tiamulin hydrogen fumarate (THF) leads to the appearance of the following residues in animal tissues: THF and metabolites that can be hydrolyzed to 8-α-hydroxymutilin. The marker residue for tiamulin, according to Regulation EEC 2377/90, is the sum of the metabolites that can be hydrolyzed to 8-α-hydroxymutilin. The main aim of this study was to analyze the depletion of tiamulin residues and metabolites that can be hydrolyzed to 8-α-hydroxymulinin by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in pig, rabbit and bird tissues after tiamulin administration and to determine minimum withdrawal times for products of animal origin intended for human consumption. Tiamulin was administered orally as follows: 12,000 µg/kg body weight/day for 7 days to pigs and rabbits and 20,000 µg tiamulin/kg body weight/day for 7 days to broiler chickens and turkeys. The values found for tiamulin marker residues were 3 times higher in liver than in muscle in pigs, 6 times in rabbits and 8-10 times in birds. The content of tiamulin residues in eggs from laying hens was below 1000 µg/kg at all times of analysis. The minimum withdrawal times for animal products intended for human consumption, resulting from this study, are 5 days for pigs, rabbits and turkeys, 3 days for broiler chickens and 0 days for eggs.

Iridium (IV) oxide-mediated microorganism nanozyme amplified immunochromatographic assay for dual-signal sensitive detection of salbutamol

Salbutamol (SAL) residues in edible animal tissues have various adverse effects on human health after digestion. Herein, we constructed an innovative functionalized microorganism nanozyme-mediated immunochromatographic assay for sensitive and accurate dual-colorimetric detection of SAL by introducing the Yeast@IrO 2 as bifunctional signal tag. The Yeast@IrO 2 was synthesized by self-assembling iridium (IV) oxide nanoparticles (IrO 2 NPs) on the surface of inactivated yeast cells, which showed high monodispersity, uniform shapes, preeminent biocompatibility and rapid antibodies labeling capacity. After reaction for 15 min, through further employing [3,3′,5,5’ Tetramethylbenzidine (TMB) and hydrogen peroxide (H 2 O 2 )] as substrate to trigger the color reaction, the developed biosensor performed with outstanding performance, including limit of detection (0.012 ng/mL), linearity (R 2 > 0.99) and selectivity. Concurrently, the visual limit of detection (0.2 μg/kg) and satisfactory recoveries (85.6%–103.9%) were obtained by monitoring SAL in pig liver and beef samples. Briefly, this work provided a universal platform for sensitive, precise and rapid detection of toxic and hazardous substances in food safety fields. • A microorganism nanozyme-mediated ICA was developed to detect salbutamol. • The Yeast@IrO 2 was designed by self-assembling IrO 2 NPs on inactivated yeast cells. • The Yeast@IrO 2 generated colorimetric- and catalytic-based dual signals. • The sensor showed lower detection limit (0.012 ng/mL) and broader detection range. • The sensor could be applied to the detection of SAL in beef and pig liver samples.

Whole Genome Sequence of a Novel Bacteriophage APT65 Infecting Aeromonas hydrophila.

Aeromonas hydrophila is a prevalent pathogenic bacterium in aquaculture that causes economic loss around the world. Antimicrobials are used to control and prevent the incidence of bacterial pathogens in aquaculture. However, they lead to the emergence of antimicrobial resistance strains and the accumulation of antibiotic residues in fish tissue. To address these issues, bacteriophages may be promising alternatives to many antibiotics in combating bacterial infections in aquaculture. The phage specific to A. hydrophila was isolated from domestic wastewater. The morphology of phages was analyzed using transmission electron microscopy. The genomic DNA of the Aeromonas phage T65 strain (APT65) phage was sequenced with a paired-end read length of 2 × 150 bp. The genome sequence was assembled and annotated. The tRNAs were predicted, and antimicrobial resistance and virulence genes were screened. A representation of the APT65 genome was constructed. The genome of APT65 is linear double-stranded DNA with 85188 base pairs having 116 open reading frames (ORFs) and a G + C content of 39.41%. The 32 ORFs were predicted to encode proteins with known phage functions. No virulence factors, antibiotic resistance genes, or temperate lifestyle genes were found. The phage is icosahedral and measures 60 nm in diameter. Based on the whole genome sequence, APT65 belongs to Lahexavirus. The taxonomic analysis of the phage with a genome length of 85,188 bp revealed that it is a new species of the genus Lahexavirus. We announce the whole genome sequence of APT65, which should be named Lahexavirus APT65, as well as the absence of antimicrobial resistance and virulence factors from its genome. Based on our results, the Lahexavirus APT65 phage may have potential as a therapeutic agent to tackle antimicrobial resistance in aquaculture.

Effect of Quercetin Nanoparticles on Hepatic and Intestinal Enzymes and Stress-Related Genes in Nile Tilapia Fish Exposed to Silver Nanoparticles.

Recently, nanotechnology has become an important research field involved in the improvement of animals' productivity, including aquaculture. In this field, silver nanoparticles (AgNPs) have gained interest as antibacterial, antiviral, and antifungal agents. On the other hand, their extensive use in other fields increased natural water pollution causing hazardous effects on aquatic organisms. Quercetin is a natural polyphenolic compound of many plants and vegetables, and it acts as a potent antioxidant and therapeutic agent in biological systems. The current study investigated the potential mitigative effect of quercetin nanoparticles (QNPs) against AgNPs-induced toxicity in Nile tilapia via investigating liver function markers, hepatic antioxidant status, apoptosis, and bioaccumulation of silver residues in hepatic tissue in addition to the whole-body chemical composition, hormonal assay, intestinal enzymes activity, and gut microbiota. Fish were grouped into: control fish, fish exposed to 1.98 mg L-1 AgNPs, fish that received 400 mg L-1 QNPs, and fish that received QNPs and AgNPs at the same concentrations. All groups were exposed for 60 days. The moisture and ash contents of the AgNP group were significantly higher than those of the other groups. In contrast, the crude lipid and protein decreased in the whole body. AgNPs significantly increased serum levels of ALT, AST, total cholesterol, and triglycerides and decreased glycogen and growth hormone (*** p < 0.001). The liver and intestinal enzymes' activities were significantly inhibited (*** p < 0.001), while the oxidative damage liver enzymes, intestinal bacterial and Aeromonas counts, and Ag residues in the liver were significantly increased (*** p < 0.001, and * p < 0.05). AgNPs also significantly upregulated the expression of hepatic Hsp70, caspase3, and p53 genes (* p < 0.05). These findings indicate the oxidative and hepatotoxic effects of AgNPs. QNPs enhanced and restored physiological parameters and health status under normal conditions and after exposure to AgNPs.

In Vitro Acaricidal Activity of Silver Nanoparticles (AgNPs) against the Poultry Red Mite (Dermanyssus gallinae)

Dermanyssus gallinae (PRM) is the most common blood-sucking ectoparasite in laying hens and is resistant against numerous acaricides. Silver nanoparticles (AgNPs) represent an innovative solution against PRM. The current study aimed to assess the in vitro acaricidal activity of AgNPs against PRM and describe their potential mechanism of action. Nanoparticles were produced using a wet chemistry approach. Mites were collected using AviVet traps from 18 poultry farms in Greece. Contact toxicity bioassays were carried out for 24 h with negative controls, 20, 40, 60, or 80 ppm AgNPs. Analysis of variance was used to compare the mortality rates of PRM between the control and treatment groups, while LC50, LC90, and LC99 values were estimated using probit regression analysis for the total farms jointly and separately. Nanoparticles displayed strong acaricidal activity, and mortality rates were significantly different between groups and increased by AgNPs concentration. Overall mean LC50, LC90, and LC99 values were 26.5, 58.8, and 112.3 ppm, respectively. Scanning electron microscopy on mites treated with 80 ppm AgNPs revealed cracks in their exoskeleton and limb detachments, presumably resulting from the interaction between AgNPs and the mites' chitin. Future studies should focus on assessing AgNPs residues in chicken tissues before moving into field trials.

Computed Tomography Perfusion Imaging in Acute Ischemic Stroke: Accurate Interpretation Matters.

Computed Tomography Perfusion Imaging in Acute Ischemic Stroke: Accurate Interpretation Matters.

Effects of starvation on the pharmacokinetics and optimal dosages of florfenicol and associated serum biochemistry in Asian seabass (Lates calcarifer).

Starvation has influence on physiology and pharmacokinetic (PK) characteristics of many drugs in land animals. However, similar PK information in fish is lacking. The current study examined the effects of starvation on fish PK, taking florfenicol (FF) in Asian seabass as an example. FF was orally administered at a single dose of 10mg/kg into 35-day starved fish reared at 25 and 30°C and the serum FF concentration was analyzed by HPLC-FLD. At 30°C, the absorption and elimination half-lives of the starved fish were increased by 30% (from 0.44 to 0.57 h) and 55% (from 7.2 to 11.18 h), respectively. The volume of distribution, clearance, and area under the curve were changed from 1.25 to 0.71 L/kg, 0.120 to 0.044 L/kg/h, and 88 to 228 h·μg/ml,respectively. Similar starvation-induced PK changes were also observed at 25°C. The serum biochemical parameters, mainly the alanine aminotransferase, aspartate aminotransferase, and glucose levels, were significantly reduced in the starvation group. Overall, FF absorption, distribution, and elimination rates were reduced by starvation, resulting in four to five times lower optimal dosage than the non-starved fish. Drug treatment in starved fish should be treated with caution as overdosing and/or tissue residues could perceivably occur.

The multicomponent residue depletion of Gelsemium elegans in pig tissues, urine, and plasma.

Gelsemium elegans (G. elegans) as a traditional medicinal plant used in livestock production. The use of G. elegans in veterinary clinics may pose safety risks to human health. The aim of this study was to investigate tissue residue depletion in pigs fed G. elegans powder. A precise quantitation method and a simultaneous semi-quantitation method for multiple components independently of standards in pig tissues were developed for the first time. The two methods were validated in terms of specificity, LODs, LOQs, linearity, accuracy, precision, and matrix effects. They were then applied to a tissue residue depletion study after G. elegans powder at a dose of 2% per kg feed were fed to pigs. Compared with precise quantitation, the method validation results indicated that the semi-quantitation method was reliable and acceptable for multicomponent quantification independent of standards. Many G. elegans alkaloids are widely distributed in most tissues of pigs. Tissue residue depletion studies indicated that 14-hydroxygelsenicine, 11-hydroxygelsenicine, and gelsemoxonine could be used as potential residue markers, and pancreas, small intestine, and lung tissues could be considered as potential residue target tissues of G. elegans. In addition, both urine and plasma could be used to predict 14-hydroxygelsenicine and gelsemoxonine residues in the liver, pancreas, and small intestinal tissues of pigs. The developed semi-quantification method can be applied to monitor the application and residue of G. elegans. The results provide scientific evidence for evaluating the safety of animal-derived food from G. elegans for consumers and will be helpful for its application and future development.

Dual-energy computed tomography as a lower radiation dose alternative to perfusion computed tomography in tumor viability assessment

To present the utility of dual-energy computed tomography (DECT) in the assessment of angiogenesis of focal lesions as an example of a solitary pulmonary nodule (SPN). This prospective study comprised 28 patients with SPN who underwent DECT and perfusion computed tomography (CTP), according to a proprietary protocol. Two radiologists independently analyzed four perfusion parameters, namely blood flow (BF), blood volume (BV), the time to maximum of the tissue residue function (Tmax), permeability surface area product (PS) from CTP, in addition to the iodine concentration (IC) and normalized iodine concentration (NIC) of the SPN from DECT. We used the Pearson R correlation and interclass correlation coefficients (ICCs). Statistical significance was assumed at p < 0.05. The mean tumor size was 23.5 ± 6.5 mm. We observed good correlations between IC and BF (r = 0.78, p < 0.000) and NIC and BF (r = 0.71, p < 0.000) as well as between IC and BV (r = 0.73, p < 0.000) and NIC and BV (r = 0.73, p < 0.000) and poor correlation between IC and PS (r = 0.38, p = 0.044).There was no correlation between NIC and PS (r = 0.35, p = 0.064), IC content and Tmax (r = − 0.28, p = 0.147) and NIC and Tmax (r = − 0.21, p = 0.266). Inter-reader agreement on quantitative parameters at CTP (ICCPS = 0.97, ICCTmax = 0.96, ICCBV = 0.98, and ICCBF = 0.99) and DECT (ICCIC = 0.98) were excellent. The radiation dose was significantly lower in DECT than that in CTP (4.84 mSv vs. 9.07 mSv, respectively). DECT is useful for the functional assessment of oncological lesions with less exposure to radiation compared to perfusion computed tomography.

Effects of sophoroflavonoside and narcissin flavonoids on mitochondrial dysfunction and antioxidant enzyme activity in rat liver poisoned with galoxyfop-r-methyl pesticide

This study delves into the accumulation of residues in the liver tissue of rats exposed to the galoxyfop-R-methyl pesticide. The investigation also evaluates the presence of malondialdehyde (MDA), a lipid peroxidation (LPO) product, in the liver mitochondrial membrane, along with the activity of antioxidant enzymes catalase, superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GP). The study further explores the impact of sophoraflavonoloside (SFL) and narcissin flavonoids on enzyme activity over a dynamic span of 10 to 40 days. In the experimental design, rats in the study group were subjected to galoxyfop-R-methyl pesticide at a dosage equivalent to LD50/10 through a specialized probe. Subsequently, the concentration of the pesticide residues in liver tissue was measured on the 5th, 10th, 20th, 30th, and 40th days post-pesticide exposure. The research also probes into the content of malondialdehyde (MDA) in the liver mitochondrial membrane, as well as the activity of antioxidant enzymes, within the context of SFL. This meticulous examination aids in comprehending the dynamics of enzyme responses and oxidative stress modulation in the liver of rats subjected to galoxyfop-R-methyl pesticide. By investigating the intricate interactions between pesticide exposure, enzyme activity, and antioxidant mechanisms, this study contributes to the broader understanding of the potential effects and counteractive measures concerning pesticide-related challenges in biological systems.

Supramolecular recognition enhanced electrochemical sensing: β-cyclodextrin and Pd nanoparticle co-decorated 3D reduced graphene oxide nanocomposite-modified glassy carbon electrode for the quantification of ractopamine.

Ractopamine (RAC) is universally known for improving lean meat percentage in livestock and thus is widely introduced as a feed additive. However, it is difficult to eliminate the RAC residue in animal tissues from the biological system and will inevitably harm human health. Hence, detecting RAC molecules in biological samples is extremely significant. Herein, a novel strategy of supramolecular recognition-enhanced electrochemical sensing is presented. This platform was constructed by coupling β-cyclodextrin (β-CD) with palladium nanoparticles (Pd NPs)-functionalized three-dimensional reduced graphene oxide (3D-rGO) to form a nanocomposite (3D-rGO/Pd/β-CD), which was further used to modify a glassy carbon electrode (GCE) for RAC detection. Benefiting from the attractive electrical conductivity and catalytic activity of 3D-rGO/Pd, as well as the unique small-molecule-recognition ability of β-CD demonstrated by 1H NMR spectrum, which revealed the 1 : 2 binding mode of RAC with β-CD, increased peak current signals of RAC were observed in the cyclic voltammetry (CV) test. Under optimized conditions, the wide linear concentration range spanned 1-95 μM, along with a relatively low detection limit of 0.12 μM (S/N = 3), as evidenced by the differential pulse voltammetry (DPV) approach. The platform also exhibited satisfactory stability and fine reproducibility, as well as high selectivity and good anti-interference capability. Moreover, this as-obtained sensor was efficiently applied in pork samples with a high recovery rate (96.44-103.99%), which provides a promising view of its electrochemical biosensing ability in practical applications.

Development and application of a mini-QuEChERS method for the determination of pesticide residues in anuran adipose tissues.

The expansion of monocultures to regions close to conservation areas has put biodiversity at risk, mainly due to the intense use of pesticides. Anurans are highly susceptible to pesticides and may be a biological marker in the contamination of an area. However, methods for determining pesticides in anurans are incipient. In this work, a miniaturized QuEChERS method was developed for the extraction of atrazine, chlorpyrifos, α- and β-endosulfan, α-, β-, θ- and ζ-cypermethrin in anuran adipose tissues. The method was optimized for the tissue sample size scale according to sample mass availability. Extracting solvent and adsorbents for the clean-up step was evaluated, achieving recoveries next to 100% with acetonitrile and without a clean-up step. The mini-QuEChERS method, using 500 mg of adipose tissue, 50 mg of NaCl and 200 mg of MgSO4, 100 μL of ultrapure water, and 1.50 mL of acetonitrile with no purification step, followed by high-performance liquid chromatography analysis and photodiode array detection was validated following the European Community guidelines. The methodology showed a moderate matrix effect for some pesticides, which was corrected using the matrix-matched calibration. The limits of quantification for the pesticide residues in adipose tissues ranged from 10 to 75 μg kg-1. Pesticide recoveries ranged from 74% to 115%, and repeatability and within-lab reproducibility showed relative standard deviations < 11%. The mini-QuEChERS method was applied to extract pesticide residues from the adipose tissues of two species of anurans: Leptodactylus macrosternum and Scinax x-signatus. 25% of samples were positive, detecting endosulfan and chlorpyriphos, confirmed by liquid chromatography coupled to tandem mass spectrometry. The mini-QuEChERS was a simple, economical, and eco-friendly method for extracting pesticide residues in anuran adipose tissue samples.

Monitoring of organophosphorus pesticide residues in plant and vegetable tissues by a novel silver nanocluster probe.

More and more attention has been paid to the problem of pesticide residues, especially in plants and vegetables, due to their close relationship with human health and food safety. Compared to conventional detecting techniques, the fluorescence sensing method has achieved good results for pesticides detection. However, most of the reported fluorescent probes needed two or more steps to achieve the detection of pesticide residues, which greatly limited their application for in vivo imaging and in situ analysis of agricultural residues in plants and vegetables. In this paper, an Ag nanoclusters (AgNCs) based fluorescent probe is developed for one-step detection of pesticide residues. The novel nanoprobe displayed impressive advantages, such as a selective response to glyphosate pesticide, rapid response within 1 min and an ultralow detection limit of 21 nM. The sensing mechanism is attributed to the unique coordination interaction between AgNCs and glyphosate, which not only increased the size of AgNCs to form big Ag particles, but also caused the fluorescence quenching of AgNCs system. Due to its favorable properties, the probe has been successfully applied to imaging the organophosphorus pesticide of glyphosate in the leave tissues of Arabidopsis thaliana and the root tip cells of lettuce for the first time.

Assessment of Tetracyclines Residues Contamination in Chicken Meat Samples of Algiers Slaughterhouses Level

Food contamination with antimicrobial residues may occur, entailing assessment and monitoring of the contamination level in edible tissue. In that way, 151 chicken meat samples were randomly collected from Algiers slaughterhouses. Otherwise, two analytical methods are validated for the simultaneous determination of oxytetracycline, tetracycline, doxycycline and chlortetracycline residues in edible chicken tissues, by liquid chromatography combined with mass spectrometry detection. Beforehand, an extraction step is performed. Indeed, acetonitrile is used as an extraction solvent for the qualitative method, and then the quantitative method is carried out after a preliminary extraction with an acidified EDTA-McIlvaine buffer, followed by a solid-phase extraction cleanup. Validation qualitative method results were satisfactory in terms of specificity (100%), sensivity, detection capability (CCß) and detection limit (LOD). Furthermore, validation results of the quantitative method was pertinent to the EU commission criteria. Thus, determination coefficient (r2) values were between de 0.91 to 0.98%, where the lowest values were observed for doxycycline. Trueness was between 85.5% and 104.8, expect for tetracycline (76.6% at 150µg/kg) and doxycycline (134.7% at 100µg/kg). As for intraday and interday precision, values respectively ranged between 12.5 and 26% and between 14 and 35%, except doxycycline for which precision values were higher. The methods have been successfully used for the identification, confirmation and quantification of tetracyclines in chicken muscle samples. Consequently, 25 samples were suspects in regard tetracyclines residues. The comparison of these samples with the QC at MRL (100µg/kg) revealed five samples needed a quantification. Thus, oxytetracycline, its epimer and doxycycline identified in samples were quantified. Indeed, all samples contained oxytetracycline and its epimer, doxycycline or both showed levels less than the decision limit (CCα).

Chitosan: a promising natural polysaccharide feed additive in poultry production systems.

In recent years, the hazardous use of antibiotic growth promotors in the poultry industry has led to the development of drug resistance and violative tissue residues. Therefore, the European Union Regulation banned application of these growth promotors, and the international authorities have searched for other natural and safe feed additive sources as substitutes for antibiotics. Chitosan has been used as a feed-additive alternative in veterinary medicine practices worldwide. Chitosan and chitosan-based nanoparticles have been extensively investigated in the poultry production system and have proved several positive impacts. The overall performance parameters of broilers and layers have been improved following dietary treatments with chitosan. Besides, chitosan showed antimicrobial activity against many bacterial, fungal, viral, and parasitic diseases as well as boosting of the immune response. Modulation of the antioxidant activity and modification of some blood parameters have also been detected owing to dietary chitosan supplementations. Moreover, chitosan nanoparticles have been now applied as a vaccine delivery vehicle and a mucosal adjuvant for many important poultry bacterial and viral diseases. Therefore, this review article sheds light on the effects of chitosan and its nanoparticle forms on the production traits of broilers and layers, their antimicrobial, immuno-regulatory, and antioxidant properties, as well as their effects on the blood constituents and vaccine production.

Effect of Temporal Sampling Rate on Estimates of the Perfusion Parameters for Patients with Moyamoya Disease Assessed with Simultaneous Multislice Dynamic Susceptibility Contrast-enhanced MR Imaging.

The effect of temporal sampling rate (TSR) on perfusion parameters has not been fully investigated in Moyamoya disease (MMD); therefore, this study evaluated the influence of different TSRs on perfusion parameters quantitatively and qualitatively by applying simultaneous multi-slice (SMS) dynamic susceptibility contrast-enhanced MR imaging (DSC-MRI). DSC-MRI datasets were acquired from 28 patients with MMD with a TSR of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (Tmax) were calculated for eight TSRs ranging from 0.5 to 4.0 s in 0.5-s increments that were subsampled from a TSR of 0.5 s datasets. Perfusion measurements and volume for chronic ischemic (Tmax ≥ 2 s) and non-ischemic (Tmax < 2 s) areas for each TSR were compared to measurements with a TSR of 0.5 s, as was visual perfusion map analysis. CBF, CBV, and Tmax values tended to be underestimated, whereas MTT and TTP values were less influenced, with a longer TSR. Although Tmax values were overestimated in the TSR of 1.0 s in non-ischemic areas, differences in perfusion measurements between the TSRs of 0.5 and 1.0 s were generally minimal. The volumes of the chronic ischemic areas with a TSR ≥ 3.0 s were significantly underestimated. In CBF and CBV maps, no significant deterioration was noted in image quality up to 3.0 and 2.5 s, respectively. The image quality of MTT, TTP, and Tmax maps for the TSR of 1.0 s was similar to that for the TSR of 0.5 s but was significantly deteriorated for the TSRs of ≥ 1.5 s. In the assessment of MMD by SMS DSC-MRI, application of TSRs of ≥ 1.5 s may lead to deterioration of the perfusion measurements; however, that was less influenced in TSRs of ≤ 1.0 s.