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BioRxiv : the Preprint Server For... May 2024Autofluorescence lifetime imaging microscopy (FLIM) is sensitive to metabolic changes in single cells based on changes in the protein-binding activities of the metabolic...
Autofluorescence lifetime imaging microscopy (FLIM) is sensitive to metabolic changes in single cells based on changes in the protein-binding activities of the metabolic co-enzymes NAD(P)H. However, FLIM typically relies on time-correlated single-photon counting (TCSPC) detection electronics on laser-scanning microscopes, which are expensive, low-throughput, and require substantial post-processing time for cell segmentation and analysis. Here, we present a fluorescence lifetime-sensitive flow cytometer that offers the same TCSPC temporal resolution in a flow geometry, with low-cost single-photon excitation sources, a throughput of tens of cells per second, and real-time single-cell analysis. The system uses a 375nm picosecond-pulsed diode laser operating at 50MHz, alkali photomultiplier tubes, an FPGA-based time tagger, and can provide real-time phasor-based classification ( ., gating) of flowing cells. A CMOS camera produces simultaneous brightfield images using far-red illumination. A second PMT provides two-color analysis. Cells are injected into the microfluidic channel using a syringe pump at 2-5 mm/s with nearly 5ms integration time per cell, resulting in a light dose of 2.65 J/cm that is well below damage thresholds (25 J/cm at 375 nm). Our results show that cells remain viable after measurement, and the system is sensitive to autofluorescence lifetime changes in Jurkat T cells with metabolic perturbation (sodium cyanide), quiescent vs. activated (CD3/CD28/CD2) primary human T cells, and quiescent vs. activated primary adult mouse neural stem cells, consistent with prior studies using multiphoton FLIM. This TCSPC-based autofluorescence lifetime flow cytometer provides a valuable label-free method for real-time analysis of single-cell function and metabolism with higher throughput than laser-scanning microscopy systems.
PubMed: 38798331
DOI: 10.1101/2024.05.15.594394 -
Highly Efficient Recovery of Au(I) from Gold Leaching Solution Using Sodium Dimethyldithiocarbamate.ACS Omega May 2024As a sustainable, nontoxic and environmentally friendly cyanide-free gold leaching agent, thiosulfate has been applied to some extent in the field of hydrometallurgy....
As a sustainable, nontoxic and environmentally friendly cyanide-free gold leaching agent, thiosulfate has been applied to some extent in the field of hydrometallurgy. However, the difficult recovery of gold ions in gold leaching solutions limits further application of thiosulfate gold leaching technology. This study demonstrated the feasibility of gold recovery by sodium dimethyldithiocarbamate (SDD) precipitation and recycling of ammonia and a lixiviant in solution. SDD achieved the purpose of recovering gold by forming granular precipitates with gold ions in solution. It can almost completely recover gold ions in 2.5-17.34 mg/L of gold leaching solution within 1 min at 25 °C, in which a gold recovery capacity of 7.99 kg/t is achieved. The leaching rate of gold ore did not change significantly after recycling the residual ammonia and thiosulfate in the leaching solution after gold recovery by SDD, and its leaching rate basically remained at 81%. The mechanism of SDD recovering Au was determined to involve the ligand exchange of SDD and Au[(SO)]. Moreover, the interaction mechanism between SDD and Au(I) was further validated by density functional theory calculations. Considering its low cost, simple technology, and environmental friendliness, the SDD precipitation process has the potential for large-scale application in gold recovery from thiosulfate gold leaching solutions.
PubMed: 38737059
DOI: 10.1021/acsomega.4c01941 -
Molecules (Basel, Switzerland) May 2024We modified -symmetric benzene-1,3,5--amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels...
We modified -symmetric benzene-1,3,5--amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, /) gels were mechanically stronger compared to other gels, and a similar trend was observed for thermal stability. Powder X-ray analysis of the xerogel obtained from various aqueous gels revealed that the packing modes of the gelators in these systems were similar. The stimuli-responsive properties of the N-BTA towards sodium/potassium salts indicated that the gel network collapsed in the presence of more nucleophilic anions such as cyanide, fluoride, and chloride salts at the MGC, but the gel network was intact when in contact with nitrate, sulphate, acetate, bromide, and iodide salts, indicating the anion-responsive properties of N-BTA gels. Anion-induced gel formation was observed for less nucleophilic anions below the MGC of N-BTA. The ability of N-BTA gels to act as an adsorbent for hazardous anionic and cationic dyes in water was evaluated. The results indicated that the ethanolic gels of N-BTA successfully absorbed methylene blue and methyl orange dyes from water. This work demonstrates the potential of the N-BTA gelator to act as a stimuli-responsive material and a promising candidate for water purification.
PubMed: 38731640
DOI: 10.3390/molecules29092149 -
Animals : An Open Access Journal From... Feb 2024plants naturally produce dhurrin, a cyanogenic glycoside that may be hydrolysed to cyanide, resulting in often-lethal toxicoses. Ruminants are particularly sensitive to...
plants naturally produce dhurrin, a cyanogenic glycoside that may be hydrolysed to cyanide, resulting in often-lethal toxicoses. Ruminants are particularly sensitive to cyanogenic glycosides due to the active role of rumen microbiota in dhurrin hydrolysis. This work provides an overview of a poisoning outbreak that occurred in 5 farms in Northwest Italy in August 2022; a total of 66 cows died, and many others developed acute toxicosis after being fed on either cultivated () or wild Sorghum (). Clinical signs were recorded, and all cows received antidotal/supportive therapy. Dead animals were subjected to necropsy, and dhurrin content was determined in Sorghum specimens using an LC-MS/MS method. Rapid onset, severe respiratory distress, recumbency and convulsions were the main clinical features; bright red blood, a bitter almond smell and lung emphysema were consistently observed on necropsy. The combined i.v. and oral administration of sodium thiosulphate resulted in a rapid improvement of clinical signs. Dhurrin concentrations corresponding to cyanide levels higher than the tolerated threshold of 200 mg/kg were detected in sorghum specimens from 4 out of 5 involved farms; thereafter, such levels declined, reaching tolerable concentrations in September-October. Feeding cattle with wild or cultivated Sorghum as green fodder is a common practice in Northern Italy, especially in summer. However, care should be taken in case of adverse climatic conditions, such as severe drought and tropical temperatures (characterising summer 2022), which are reported to increase dhurrin synthesis and storage.
PubMed: 38473128
DOI: 10.3390/ani14050743 -
Clinical Case Reports Jan 2024We present a case of a 36-year-old woman with a history of three suicide attempts who had ingested approximately 40 bitter almonds in a suicidal act, leading to her...
We present a case of a 36-year-old woman with a history of three suicide attempts who had ingested approximately 40 bitter almonds in a suicidal act, leading to her admission to the emergency department of a regional hospital due to complaints of vomiting. Upon arrival, she exhibited confusion, and her vital signs were recorded as follows: pulse rate = 117 beats/min, blood pressure = 160/85 mmHg, oxygen saturation = 95%, respiratory rate = 16, temperature = 37°C. The patient venous blood gas analysis manifested severe metabolic acidosis (pH = 6.92, pO = 43 mmHg, HCO = 8.6 mmol/L, pCO = 42.7 mmHg, base excess = -25.9 mmol/L). Four hours later, she became unconscious and she was intubated. Gastric lavage and a single dose of 60 g of activated charcoal and sodium bicarbonate were administered. In the referral hospital, sodium nitrite was given due to the severity of the poisoning, and norepinephrine infusion was initiated to manage hypotension. Within a day, the patient regained consciousness, underwent extubation, and after 72 h was discharged and subsequently transferred to psychiatric care for further treatment. This case underscores the critical, life-threatening implications of cyanide toxicity following the ingestion of bitter almonds, highlighting the efficacy of supportive measures such as gastric lavage, activated charcoal, and sodium bicarbonate. Furthermore, it emphasizes the successful application of sodium nitrite monotherapy in managing this condition.
PubMed: 38197062
DOI: 10.1002/ccr3.8418 -
Frontiers in Microbiology 2023The high pathogenicity of is attributed to the production of many virulence factors and its resistance to several antimicrobials. Among them, sodium hypochlorite...
The high pathogenicity of is attributed to the production of many virulence factors and its resistance to several antimicrobials. Among them, sodium hypochlorite (NaOCl) is a widely used disinfectant due to its strong antimicrobial effect. However, bacteria develop many mechanisms to survive the damage caused by this agent. Therefore, this study aimed to identify novel mechanisms employed by to resist oxidative stress induced by the strong oxidizing agent NaOCl. We analyzed the growth of the mutants Δ, Δ, Δ, Δ, Δ at 1 μg/mL NaOCl, and showed that these known HO resistance mechanisms are also important for the survival of under NaOCl stress. We then conducted a screening of the PA14 transposon insertion mutant library and identified 48 mutants with increased susceptibility toward NaOCl. Among them were 10 mutants with a disrupted PA4166, or gene, which also exhibited a significant growth defect in the presence of NaOCl. We focussed our follow-up experiments (i.e., growth analyzes and kill-kinetics) on mutants with defect in the synthesis of the secondary metabolite hydrogen cyanide (HCN). We showed that HCN produced by contributes to its resistance toward NaOCl as it acts as a scavenger molecule, quenching the toxic effects of NaOCl.
PubMed: 38033579
DOI: 10.3389/fmicb.2023.1294518 -
Applied and Environmental Microbiology Oct 2023grows as a biofilm under many environmental conditions, and the bacterium can disperse from biofilms via highly regulated, dynamic processes. However, physiologic...
grows as a biofilm under many environmental conditions, and the bacterium can disperse from biofilms via highly regulated, dynamic processes. However, physiologic triggers of biofilm dispersal remain poorly understood. Based on prior literature describing dispersal triggered by forms of starvation, we tested bacterial respiratory inhibitors for biofilm dispersal in two models resembling chronic airway infections. Our underlying hypothesis was that respiratory inhibitors could serve as a model for the downstream effects of starvation. We used two experimental conditions. In the first condition, biofilms were grown and dispersed from the surface of airway epithelial cells, and the second condition was a model where biofilms were grown on glass in cell culture media supplemented with host-relevant iron sources. In both biofilm models, the respiratory inhibitors potassium cyanide and sodium azide each triggered biofilm dispersal. We hypothesized that cyanide-induced dispersal was due to respiratory inhibition rather than signaling via an alternative mechanism, and, indeed, if respiration was supported by overexpression of cyanide-insensitive oxidase, dispersal was prevented. Dispersal required the activity of the cyclic-di-GMP regulated protease LapG, reinforcing the role of matrix degradation in dispersal. Finally, we examined the roles of individual phosphodiesterases, previously implicated in dispersal to specific triggers, and found signaling to be highly redundant. Combined deletion of the phosphodiesterases , , and was required to attenuate the dispersal phenotype. In summary, this work adds insight into the physiology of biofilm dispersal under environmental conditions in which bacterial respiration is abruptly limited. IMPORTANCE The bacterium grows in biofilm communities that are very difficult to treat in human infections. Growing as a biofilm can protect bacteria from antibiotics and the immune system. Bacteria can leave a biofilm through a process called "dispersal." Dispersed bacteria seed new growth areas and are more susceptible to killing by antibiotics. The triggers for biofilm dispersal are not well understood, and if we understood dispersal better it might lead to the development of new treatments for infection. In this paper, we find that inhibiting ability to respire (generate energy) can trigger dispersal from a biofilm grown in association with human respiratory epithelial cells in culture. The dispersal process requires a protease which is previously known to degrade the biofilm matrix. These findings give us a better understanding of how the biofilm dispersal process works so that future research can discover better ways of clearing bacteria growing in biofilms.
Topics: Humans; Pseudomonas aeruginosa; Biofilms; Phosphoric Diester Hydrolases; Anti-Bacterial Agents; Peptide Hydrolases; Cyanides; Gene Expression Regulation, Bacterial; Bacterial Proteins; Cyclic GMP
PubMed: 37728340
DOI: 10.1128/aem.01101-23 -
Circulation Oct 2023In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory... (Review)
Review
2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.
Topics: Humans; Adrenergic beta-Antagonists; American Heart Association; Benzodiazepines; Cardiopulmonary Resuscitation; Digoxin; Heart Arrest; United States
PubMed: 37721023
DOI: 10.1161/CIR.0000000000001161 -
Forensic Sciences Research Jun 2023
PubMed: 37621451
DOI: 10.1093/fsr/owad015 -
Journal of Orthopaedic Surgery and... Aug 2023Elevated levels of oxidative stress as a consequence of estrogen deficiency serve as a key driver of the onset of osteoporosis (OP). In addition to increasing the risk...
BACKGROUND
Elevated levels of oxidative stress as a consequence of estrogen deficiency serve as a key driver of the onset of osteoporosis (OP). In addition to increasing the risk of bone fractures, OP can reduce the bone volume proximal to titanium nails implanted to treat these osteoporotic fractures, thereby contributing to titanium nail loosening. Sodium butyrate (NaB) is a short-chain fatty acid produced by members of the gut microbiota that exhibits robust antioxidant and anti-inflammatory properties.
METHODS
OP fracture model rats parameters including bone mineral density (BMD), new bone formation, and the number of bonelets around the implanted nail were analyzed via micro-CT scans, H&E staining, and Masson's staining. The protective effects of NaB on such osseointegration and the underlying mechanisms were further studied in vitro using MC3T3-E1 cells treated with carbonyl cyanide m-chlorophenylhydrazone (CCCP) to induce oxidative stress. Techniques including Western immunoblotting, electron microscopy, flow cytometry, alkaline phosphatase (ALP) staining, and osteoblast mineralization assays were employed to probe behaviors such as reactive oxygen species production, mineralization activity, ALP activity, protein expression, and the ability of cells to attach to and survive on titanium plates.
RESULTS
NaB treatment was found to enhance ALP activity, mineralization capacity, and Coll-I, BMP2, and OCN expression levels in CCCP-treated MC3T3-E1 cells, while also suppressing PKC and NF-κB expression and enhancing Nrf2 and HO-1 expression in these cells. NaB further suppressed intracellular ROS production and malondialdehyde levels within the cytosol while enhancing superoxide dismutase activity and lowering the apoptotic death rate. In line with these results, in vivo work revealed an increase in BMD in NaB-treated rats that was associated with enhanced bone formation surrounding titanium nails.
CONCLUSION
These findings indicate that NaB may represent a valuable compound that can be postoperatively administered to aid in treating OP fractures through the enhancement of titanium nail osseointegration.
Topics: Rats; Animals; Reactive Oxygen Species; Osseointegration; NF-kappa B; Titanium; Butyric Acid; Protein Kinase C-alpha; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Nails; Osteogenesis
PubMed: 37528483
DOI: 10.1186/s13018-023-04013-y