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Journal of Chromatography. A May 2024Birds are excellent bioindicators of environmental pollution, and blood provides information on contaminant exposure, although its analysis is challenging because of the...
Optimization and uncertainty assessment of a gas chromatography coupled to Orbitrap mass spectrometry method to determine organic contaminants in blood: A case study of an endangered seabird.
Birds are excellent bioindicators of environmental pollution, and blood provides information on contaminant exposure, although its analysis is challenging because of the low volumes that can be sampled. The objective of the present study was to optimize and validate a miniaturized and functional extraction and analytical method based on gas chromatography coupled to Orbitrap mass spectrometry (GCOrbitrap-MS) for the trace analysis of contaminants in avian blood. Studied compounds included 25 organochlorine pesticides (OCPs), 6 polychlorinated biphenyls (PCBs), 8 polybrominated diphenyl ethers (PBDEs) and 15 polycyclic aromatic hydrocarbons (PAHs). Four extraction and clean-up conditions were optimized and compared in terms of efficiency, accuracy, and uncertainty assessment. Extraction with hexane:dichloromethane and miniaturized Florisil pipette clean-up was the most adequate considering precision and accuracy, time, and costs, and was thereafter used to analyse 20 blood samples of a pelagic seabird, namely the Bermuda petrel (Pterodroma cahow). This species, endemic to the Northwest Atlantic, is among the most endangered seabirds of the region that in the '60 faced a decrease in the breeding success likely linked to a consistent exposure to dichloro-diphenyl-trichloroethane (DDT). Indeed, p,p'-DDE, the main DDT metabolite, was detected in all samples and ranged bewteen 1.13 and 6.87 ng/g wet weight. Other ubiquitous compounds were PCBs (ranging from 0.13 to 6.76 ng/g ww), hexachlorobenzene, and mirex, while PAHs were sporadically detected at low concentrations, and PBDEs were not present. Overall, the extraction method herein proposed allowed analysing very small blood volumes (∼ 100 µL), thus respecting ethical principles prioritising the application of less-invasive sampling protocols, fundamental when studying threatened avian species.
Topics: Animals; Gas Chromatography-Mass Spectrometry; Pesticides; Birds; Hydrocarbons, Chlorinated; Polychlorinated Biphenyls; Halogenated Diphenyl Ethers; Polycyclic Aromatic Hydrocarbons; Endangered Species; Environmental Monitoring; Environmental Pollutants
PubMed: 38604058
DOI: 10.1016/j.chroma.2024.464870 -
Frontiers in Veterinary Science 2024Mosquito-borne diseases pose serious public health threats in Zhejiang Province, China, and vector control is believed to be the primary method for reducing...
BACKGROUND
Mosquito-borne diseases pose serious public health threats in Zhejiang Province, China, and vector control is believed to be the primary method for reducing transmission. Due to severe resistance problems, effective and sustainable methods without chemical insecticides are urgently required to control mosquito vectors. Attractive toxic sugar baits (ATSB) are newly developed methods to control mosquitoes in recent decades with the core element sugar bait, which was invented according to the sugar-feeding behavior of mosquitoes. In this study, we developed a Novel Sugar Bait Device (NSBD) trap by combining sugar bait and physical adhesive capture technology. The study aimed to evaluate the effect of the NSBD trap on controlling mosquitoes in residential environments and to identify the optimal sugar solution concentration in the sugar bait of the NSBD for real use.
METHODS
Four residential villages in Ningbo City with similar geographic environments and mosquito densities were selected for field trials in 2022. One village (site 1) was designated as the control group, and three villages (sites 2-4) served as the test groups to assess the effectiveness of NSBD traps with different sugar solution concentrations (6, 8, and 10%) in the sugar bait. Larval and adult mosquito densities were monitored monthly before and semi-monthly after the trials using the CDC light trap and larval pipette method.
RESULTS
Before the trials, we monitored mosquito density for 3 months to confirm the baseline mosquito density among the four sites, and no statistical differences in adult and larval mosquitoes were found (adult, = 3.047, > 0.05; larvae, = 0.436, > 0.05). After the trials, all NCBD traps effectively controlled larval and adult mosquito densities, with the highest standard decrease rates of larval and adult mosquito densities at 57.80 and 86.31%, respectively, observed in site 4. The most suitable sugar solution concentration in the sugar bait was 10%.
CONCLUSION
NSBD traps effectively controlled mosquitoes in residential environments during field trials. Without the use of insecticides, this may be a promising choice for mosquito vector control to prevent mosquito-borne diseases.
PubMed: 38601912
DOI: 10.3389/fvets.2024.1364740 -
Microsystems & Nanoengineering 2024Studying the membrane physiology of filamentous fungi is key to understanding their interactions with the environment and crucial for developing new therapeutic...
Studying the membrane physiology of filamentous fungi is key to understanding their interactions with the environment and crucial for developing new therapeutic strategies for disease-causing pathogens. However, their plasma membrane has been inaccessible for a micron-sized patch-clamp pipette for pA current recordings due to the rigid chitinous cell wall. Here, we report the first femtosecond IR laser nanosurgery of the cell wall of the filamentous fungi, which enabled patch-clamp measurements on protoplasts released from hyphae. A reproducible and highly precise (diffraction-limited, submicron resolution) method for obtaining viable released protoplasts was developed. Protoplast release from the nanosurgery-generated incisions in the cell wall was achieved from different regions of the hyphae. The plasma membrane of the obtained protoplasts formed tight and high-resistance (GΩ) contacts with the recording pipette. The entire nanosurgical procedure followed by the patch-clamp technique could be completed in less than 1 hour. Compared to previous studies using heterologously expressed channels, this technique provides the opportunity to identify new ionic currents and to study the properties of the ion channels in the protoplasts of filamentous fungi in their native environment.
PubMed: 38590818
DOI: 10.1038/s41378-024-00664-x -
BioRxiv : the Preprint Server For... Mar 2024The small amount of human tissue available for testing is a paramount challenge in cancer drug development, cancer disease models, and personalized oncology....
The small amount of human tissue available for testing is a paramount challenge in cancer drug development, cancer disease models, and personalized oncology. Technologies that combine the microscale manipulation of tissues with fluid handling offer the exciting possibility of miniaturizing and automating drug evaluation workflows. This approach minimizes animal testing and enables inexpensive, more efficient testing of samples with high clinical biomimicry using scarce materials. We have developed an inexpensive platform based on an off-the-shelf robot that can manipulate microdissected tissues (µDTs) into user-programmed positions without using intricate microfluidic designs nor any other accessories such as a microscope or a pneumatic controller. The robot integrates complex functions such as vision and fluid actuation by incorporating simple items including a USB camera and a rotary pump. Through the robot's camera, the platform software optically recognizes randomly-seeded µDTs on the surface of a petri dish and positions a mechanical arm above the µDTs. Then, a custom rotary pump actuated by one of the robot's motors generates enough microfluidic lift to hydrodynamically pick and place µDTs with a pipette at a safe distance from the substrate without requiring a proximity sensor. The platform's simple, integrated construction is cost-effective and compact, allowing placement inside a tissue culture hood for sterile workflows. The platform enables users to select µDTs based on their size, place them in user-programmed arrays, such as multi-well plates, and control various robot motion parameters. As a case application, we use the robotic system to conduct semi-automated drug testing of mouse and human µDTs in 384-well plates. Our user-friendly platform promises to democratize microscale tissue research to clinical and biological laboratories worldwide.
PubMed: 38586030
DOI: 10.1101/2024.03.21.586169 -
BMC Women's Health Apr 2024Women presenting with abnormal uterine bleeding needs careful and thorough assessment including ultrasound examination of endometrium and histopathological assessment of...
Rate and risk factors of inadequate endometrial tissues after endometrial sampling among Bhutanese women at the national referral hospital of Bhutan: a cross-sectional study.
INTRODUCTION
Women presenting with abnormal uterine bleeding needs careful and thorough assessment including ultrasound examination of endometrium and histopathological assessment of the endometrial tissues. The objective of this cross-sectional study was to determine the rate and the factors associated with inadequate endometrial tissues after endometrial sampling using MedGyn® pipette among Bhutanese women at the colposcopy clinic, Jigme Dorji Wangchuck National Referral Hospital (JDWNRH), Bhutan.
METHODS
This cross-sectional study was conducted at the colposcopy clinic, JDWNRH, Thimphu between October, 2021 and March, 2022. Women included in this study underwent endometrial sampling using MedGyn® pipette without anesthesia as an office procedure. Data were collected using an interviewer-administered questionnaire and results extracted into a structured pro forma. The histopathology reports were extracted from the Department of Pathology and Laboratory Medicine, JDWNRH using the unique Bhutanese citizenship identity card number of the study participants.
RESULTS
Inadequate endometrial tissues were noted in 27% (33 out of 122 cases). Among 89 patients with an adequate endometrial tissue, histologic results were normal in 30 (33.7%), benign pathology in 22 (24.7%), atrophy in 10 (8.2%), and hyperplasia in 27 (30.3%). In a univariate analysis, menopausal state (OR 1.6, 95% CI 0.708-3.765), overweight and obese (OR 1.6 95% CI 0.640-3.945), unemployed (OR 1.7, 95% CI 0.674-1.140), nulliparous (OR 1.7, 95% CI 0.183-15.816), primipara (OR 5.1, 95% CI 0.635-40.905) and use of hormonal contraception (OR 2.1, 95% CI 0.449-10.049) were associated with increased risk of inadequate endometrial tissues. On multivariate regression analysis, nulliparity (OR 1.1, 95% CI 0.101-12.061), overweight and obesity (OR 1.4, 95% CI 0.490-3.917), use of hormonal contraceptives (OR 2.2, 95% CI 0.347-13.889), and junior surgeons (OR 1.1, 95%CI 0.463-2.443) were found to be associated with inadequate endometrial tissues. However, the above associations were not statistically significant (p > 0.05).
CONCLUSION
The rate of inadequate endometrial tissue following endometrial sampling using MedGyn® pipette was 27.0%. Factors associated with an increased risk of inadequate endometrial tissue after endometrial sampling were menopausal state, overweight and obese, unemployed, nulliparous, primipara and use of hormonal contraception.
Topics: Humans; Female; Bhutan; Cross-Sectional Studies; Overweight; Endometrium; Obesity; Risk Factors; Referral and Consultation; Uterine Hemorrhage; Endometrial Neoplasms
PubMed: 38566186
DOI: 10.1186/s12905-024-03047-6 -
Sensors (Basel, Switzerland) Mar 2024This paper presents high-sensitivity sensors based on an open complementary square split-ring resonator and a modified open complementary split-ring resonator operating...
This paper presents high-sensitivity sensors based on an open complementary square split-ring resonator and a modified open complementary split-ring resonator operating at 4.5 GHz and 3.4 GHz, respectively. The sensors are designed for the detection of multiple liquid materials, including distilled water, methanol, and ethanol. The liquid under test is filled in a glass container loaded using a pipette. Compared to the conventional OCSSRR, the modified OCSSRR with multiple rings exhibits a higher frequency shift of 1200 MHz, 1270 MHz, and 1520 MHz for ethanol, methanol, and distilled water, respectively. The modified sensor also demonstrates a high sensitivity of 308 MHz/RIU for ethanol concentration which is the highest among the existing microwave sensors. The sensors in this manuscript are suitable for multiple liquid-material-sensing applications.
PubMed: 38544102
DOI: 10.3390/s24061840 -
Biophysical Journal Mar 2024Compaction is the first morphogenetic movement of the eutherian mammals and involves a developmentally regulated adhesion process. Previous studies investigated cellular...
Compaction is the first morphogenetic movement of the eutherian mammals and involves a developmentally regulated adhesion process. Previous studies investigated cellular and mechanical aspects of compaction. During mouse and human compaction, cells spread onto each other as a result of a contractility-mediated increase in surface tension pulling at the edges of their cell-cell contacts. However, how compaction may affect the mechanical stability of cell-cell contacts remains unknown. Here, we used a dual pipette aspiration assay on cell doublets to quantitatively analyze the mechanical stability of compacting mouse embryos. We measured increased mechanical stability of contacts with rupture forces growing from 40 to 70 nN, which was highly correlated with cell-cell contact expansion. Analyzing the dynamic molecular reorganization of cell-cell contacts, we find minimal recruitment of the cell-cell adhesion molecule Cdh1 (also known as E-cadherin) to contacts but we observe its reorganization into a peripheral adhesive ring. However, this reorganization is not associated with increased effective bond density, contrary to previous reports in other adhesive systems. Using genetics, we reduce the levels of Cdh1 or replace it with a chimeric adhesion molecule composed of the extracellular domain of Cdh1 and the intracellular domain of Cdh2 (also known as N-cadherin). We find that reducing the levels of Cdh1 impairs the mechanical stability of cell-cell contacts due to reduced contact growth, which nevertheless show higher effective bond density than wild-type contacts of similar size. On the other hand, chimeric adhesion molecules cannot form large or strong contacts indicating that the intracellular domain of Cdh2 is unable to reorganize contacts and/or is mechanically weaker than the one of Cdh1 in mouse embryos. Together, we find that mouse embryo compaction mechanically strengthens cell-cell adhesion via the expansion of Cdh1 adhesive rings that maintain pre-compaction levels of effective bond density.
PubMed: 38528761
DOI: 10.1016/j.bpj.2024.03.028 -
Advanced Science (Weinheim,... Jun 2024Digital PCR (dPCR) holds immense potential for precisely detecting nucleic acid markers essential for personalized medicine. However, its broader application is hindered...
Digital PCR (dPCR) holds immense potential for precisely detecting nucleic acid markers essential for personalized medicine. However, its broader application is hindered by high consumable costs, complex procedures, and restricted multiplexing capabilities. To address these challenges, an all-in-one dPCR system is introduced that eliminates the need for microfabricated chips, offering fully automated operations and enhanced multiplexing capabilities. Using this innovative oscillation-induced droplet generation technique, OsciDrop, this system supports a comprehensive dPCR workflow, including precise liquid handling, pipette-based droplet printing, in situ thermocycling, multicolor fluorescence imaging, and machine learning-driven analysis. The system's reliability is demonstrated by quantifying reference materials and evaluating HER2 copy number variation in breast cancer. Its multiplexing capability is showcased with a quadruplex dPCR assay that detects key EGFR mutations, including 19Del, L858R, and T790M in lung cancer. Moreover, the digital stepwise melting analysis (dSMA) technique is introduced, enabling high-multiplex profiling of seven major EGFR variants spanning 35 subtypes. This innovative dPCR system presents a cost-effective and versatile alternative, overcoming existing limitations and paving the way for transformative advances in precision diagnostics.
Topics: Humans; Breast Neoplasms; Molecular Diagnostic Techniques; Reproducibility of Results; Polymerase Chain Reaction; Pathology, Molecular; ErbB Receptors; DNA Copy Number Variations; Lung Neoplasms; Receptor, ErbB-2; Multiplex Polymerase Chain Reaction; Mutation; Female
PubMed: 38516754
DOI: 10.1002/advs.202309557 -
Se Pu = Chinese Journal of... Mar 2024Algal toxins are secondary metabolites produced by harmful algae; these metabolites are characterized with strong toxicity, diverse structure and bioaccumulation....
Algal toxins are secondary metabolites produced by harmful algae; these metabolites are characterized with strong toxicity, diverse structure and bioaccumulation. Aquatic organisms that feed on harmful algae can accumulate algal toxins in their bodies, and the consumption of these organisms by humans can cause symptoms of paralysis, diarrhea, and even death. The onset of poisoning can occur within as little as 30 min; in many cases, no suitable antidote for algal toxins is available. Thus, algal toxins present significant threats to human health, the aquaculture industry, and aquatic ecosystems. Because the potential risks of algal toxins are a critical issue, these toxins have become a research hotspot. The water environment and various types of aquatic products should be monitored and analyzed to ensure their safety. However, because of possible matrix effects and the low content of algal toxins in actual samples, an efficient pretreatment method is necessary prior to instrumental analyses. Efficient sample pretreatment techniques can not only reduce or eliminate interferences from the sample matrix during analysis but also enrich the target analytes to meet the detection limit of the analytical instrument, thereby ensuring the sensitivity and accuracy of the detection method. In recent years, sample pretreatment techniques such as solid-phase extraction (SPE), solid-phase microextraction (SPME), magnetic SPE (MSPE), dispersive SPE (DSPE), and pipette tip-based SPE (PT-SPE) have gained wide attention in the field of algal-toxin separation and analysis. The performance of these pretreatment techniques largely depends on the characteristics of the extraction materials. Given the diverse physicochemical properties of algal toxins, including their different molecular sizes, hydrophobicity/hydrophilicity, and charges, the design and preparation of materials suitable for algal-toxin extraction is an essential undertaking. The optimal extraction material should be capable of reversible algal-toxin adsorption and preferably possess a porous structure with a large surface area to allow for high recovery rates and good interfacial contact with the toxins. Additionally, the extraction material should exhibit good chemical stability in the sample solution and elution solvent within the working pH range; otherwise, it may dissolve or lose its functional groups. Many research efforts have sought to develop novel adsorbent materials with these properties in the separation and analysis of algal toxins, focusing on carbon-based materials, metal organic frameworks (MOFs), covalent organic frameworks (COFs), molecularly imprinted polymers (MIPs), and their functionalized counterparts. Carbon-based materials, MOFs, and COFs have advantages such as large surface areas and abundant adsorption sites. These extraction materials are widely used in the separation and analysis of target substances in complex environmental, biological, and food samples owing to their excellent performance and unique microstructure. They are also the main adsorbents used for the extraction of algal toxins. These extraction materials play an essential role in the extraction of algal toxins, but they also present a number of limitations: (1) Carbon-based materials, MOFs, and COFs have relatively poor selective-adsorption ability towards target substances; (2) Most MOFs are unstable in aqueous solutions and challenging to apply during extraction from water-based sample solutions; (3) COFs mainly consist of lightweight elements, rendering them difficult to completely separate from sample solutions using centrifugal force, which limits their application range; (4) Although MIPs have good selectivity, issues such as template-molecule loss, slow mass-transfer rates, and low adsorption capacity must be addressed. Therefore, the design and preparation of novel functionalized extraction materials specifically tailored for algal toxins and studies on new composite extraction materials are highly desirable. This article collects representative literature from domestic and international research on algal-toxin analysis over the past decade, summarizes the relevant findings, categorizes the applications of novel functional materials in algal-toxin-extraction processes, and provides an outlook on their future development prospects.
Topics: Humans; Ecosystem; Adsorption; Aquaculture; Carbon; Water; Solid Phase Extraction
PubMed: 38503699
DOI: 10.3724/SP.J.1123.2023.10006 -
The Journal of Biological Chemistry Apr 2024Mechanically activated Piezo1 channels undergo transitions from closed to open-state in response to pressure and other mechanical stimuli. However, the molecular details...
Mechanically activated Piezo1 channels undergo transitions from closed to open-state in response to pressure and other mechanical stimuli. However, the molecular details of these mechanosensitive gating transitions are unknown. Here, we used cell-attached pressure-clamp recordings to acquire single channel data at steady-state conditions (where inactivation has settled down), at various pressures and voltages. Importantly, we identify and analyze subconductance states of the channel which were not reported before. Pressure-dependent activation of Piezo1 increases the occupancy of open and subconductance state at the expense of decreased occupancy of shut-states. No significant change in the mean open time of subconductance states was observed with increasing negative pipette pressure or with varying voltages (ranging from -40 to -100 mV). Using Markov-chain modeling, we identified a minimal four-states kinetic scheme, which recapitulates essential characteristics of the single channel data, including that of the subconductance level. This study advances our understanding of Piezo1-gating mechanism in response to discrete stimuli (such as pressure and voltage) and paves the path to develop cellular and tissue level models to predict Piezo1 function in various cell types.
Topics: Humans; HEK293 Cells; Ion Channel Gating; Ion Channels; Kinetics; Markov Chains; Mechanotransduction, Cellular; Pressure
PubMed: 38479601
DOI: 10.1016/j.jbc.2024.107156