Comparison of feline and human immunodeficiency virus reverse transcriptase enzymes through chemical screening and computational analysis.

Feline immunodeficiency virus (FIV) is a common infection found in domesticated and wild cats worldwide. Despite the wealth of therapeutic understanding of the disease in humans, considerably less information exists regarding the treatment of the disease in felines. Current treatment relies on drugs developed for the related human immunodeficiency virus (HIV) and includes compounds of the popular non-nucleotide reverse transcriptase (NNRTI) class. This is despite FIV-RT being only 67% similar to HIV-1 RT at the enzyme level, increasing to 88% for the allosteric pocket targeted by NNRTIs. The goal of this project was to try to quantify how well the more extensive pharmacological knowledge available for human disease translates to felines. To this end we screened known NNRTIs and 10 diverse pyrimidine analogs identified virtually. We use this chemo-centric probe approach to (a) assess the similarity between the two related RT targets based on the observed experimental inhibition values, (b) try to identify more potent inhibitors at FIV, and (c) gain a better appreciation of the structure-activity relationships (SAR). We found the correlation between IC50s at the two targets to be strong (r2 = 0.87) and identified compound 1 as the most potent inhibitor of FIV with IC50 of 0.030 µM ± 0.009. This compared to FIV IC50 values of 0.22 ± 0.17 µM, 0.040 ± 0.010 µM and >160 µM for known anti HIV-1 RT drugs Efavirenz, Rilpivirine, and Nevirapine, respectively. This knowledge, along with an understanding of the structural origin that give rise to any differences could improve the way HIV drugs are repurposed for FIV.

Advances in the Synthesis of Bioorthogonal Reagents: s-Tetrazines, 1,2,4-Triazines, Cyclooctynes, Heterocycloheptynes, and trans-Cyclooctenes.

Aligned with the increasing importance of bioorthogonal chemistry has been an increasing demand for more potent, affordable, multifunctional, and programmable bioorthogonal reagents. More advanced synthetic chemistry techniques, including transition-metal-catalyzed cross-coupling reactions, C-H activation, photoinduced chemistry, and continuous flow chemistry, have been employed in synthesizing novel bioorthogonal reagents for universal purposes. We discuss herein recent developments regarding the synthesis of popular bioorthogonal reagents, with a focus on s-tetrazines, 1,2,4-triazines, trans-cyclooctenes, cyclooctynes, hetero-cycloheptynes, and -trans-cycloheptenes. This review aims to summarize and discuss the most representative synthetic approaches of these reagents and their derivatives that are useful in bioorthogonal chemistry. The preparation of these molecules and their derivatives utilizes both classical approaches as well as the latest organic chemistry methodologies.

Development of Novel Immobilized Copper-Ligand Complex for Click Chemistry of Biomolecules.

Copper-catalyzed azide-alkyne cycloaddition click (CuAAC) reaction is widely used to synthesize drug candidates and other biomolecule classes. Homogeneous catalysts, which consist of copper coordinated to a ligand framework, have been optimized for high yield and specificity of the CuAAC reaction, but CuAAC reaction with these catalysts requires the addition of a reducing agent and basic conditions, which can complicate some of the desired syntheses. Additionally, removing copper from the synthesized CuAAC-containing biomolecule is necessary for biological applications but inconvenient and requires additional purification steps. We describe here the design and synthesis of a PNN-type pincer ligand complex with copper (I) that stabilizes the copper (I) and, therefore, can act as a CuAAC catalyst without a reducing agent and base under physiologically relevant conditions. This complex was immobilized on two types of resin, and one of the immobilized catalyst forms worked well under aqueous physiological conditions. Minimal copper leaching was observed from the immobilized catalyst, which allowed its use in multiple reaction cycles without the addition of any reducing agent or base and without recharging with copper ion. The mechanism of the catalytic cycle was rationalized by density functional theory (DFT). This catalyst's utility was demonstrated by synthesizing coumarin derivatives of small molecules such as ferrocene and sugar.

Clinical study of 400mg efavirenz treatment in newly diagnosed patients with HIV/AIDS.

The efficacy of 400mg efavirenz (EFV) once daily is reported to be similar to that of 600mg EFV. However, EFV-related toxic and side effects of 400mg EFV are significantly reduced. Here, the feasibility of reducing EFV to 400mg once a day in HIV-infected/AIDS patients was evaluated. Fifty patients were included. Patients were given 3TC+TDF+400mg EFV (n=25) or 3TC+TDF+600mg EFV (n=25). The proportion of patients with HIV RNA < 40 copies/mL and the adverse events served as the primary and secondary outcomes, respectively. HIV inhibition rates of the 3TC+TDF+400mg EFV group and 3TC+TDF+600mg EFV group were both 56.52% at week 24 and respectively 100%, 91.3% at week 48. During 48 weeks, 27 cases of adverse events were reported in the 3TC+TDF+400mg EFV group, lower than those in the 3TC+TDF+600mg EFV group, which had 39 cases. Compared with the 3TC+TDF+400mg EFV group, the incidence of transaminase, dizziness, hyperlipidemia and rashes all increased in the 3TC+TDF+600mg EFV group (P>0.05). No serious adverse events of the central nervous system occurred. The incidence of depression, sleep disturbance, and vertigo were similar (P>0.05). The efficacy of 400mg EFV is comparable to 600mg EFV. However, patients receiving 400mg EFV have fewer adverse events.

Functionalization of Siloxanes with Arynes Generated from o-Triazenylarylboronic Acids.

Herein, we report the functionalization of polyhedral oligosilsesquioxanes (POSS) and related siloxanes with arynes. Using o-triazenylarylboronic acids as aryne precursors and silica gel as the activator, the transformation of siloxane bearing various arynophilic moieties on the side chains was achieved with high yields without touching the siloxane core. This method was applied to the conjugation of POSS and pharmaceutical cores using an aryne derived from the synthetic intermediate of cabozantinib. Furthermore, orthogonal dual functionalization of POSS was realized by combining the aryne reaction with Huisgen cyclization.

Synthesis of a Side Chain Alkyne Analogue of Sitosterol as a Chemical Probe for Imaging in Plant Cells.

Clickable chemical tools are essential for studying the localization and role of biomolecules in living cells. For this purpose, alkyne-based close analogs of the respective biomolecules are of outstanding interest. Here, in the field of phytosterols, we present the first alkyne derivative of sitosterol, which fulfills the crucial requirements for such a chemical tool as follows: very similar in size and lipophilicity to the plant phytosterols, and correct absolute configuration at C-24. The alkyne sitosterol FB-DJ-1 was synthesized, starting from stigmasterol, which comprised nine steps, utilizing a novel alkyne activation method, a Johnson-Claisen rearrangement for the stereoselective construction of a branched sterol side chain, and a Bestmann-Ohira reaction for the generation of the alkyne moiety.

Introducing terminal alkyne groups at the reducing end of cellulose nanocrystals by aldimine condensation for further click reaction.

In recent years, click reactions with cellulose nanocrystals (CNC) participation have gradually become a research hotspot. Carboxylamine condensation is the most used method to introduce terminal alkyne groups at the reducing end of CNC as reaction sites for click reactions. However, hydroxyl groups on CNC surface would be slightly oxidized during the carboxyamine condensation process, inducing the potential positions of introduced alkynes would be not only at the reducing end but also on CNC surface. Here, aldimine condensation was proposed to introduce terminal alkyne groups just at the reducing end of CNC, and a systematic comparison analysis was conducted with carboxylamine condensation. Firstly, the selectivity and extent of alkynylation were characterized by XPS and EA. Secondly, the end aldehyde content in these CNC samples was measured by the BCA method, which quantitatively explained the grafting efficiency of aldimine condensation and further verified its feasibility. Thirdly, the clickability of the modified CNC samples was confirmed through XPS analysis of the products after a pre-designed click reaction. In sum, aldimine condensation was proven to be a simple and effective strategy for introducing terminal alkyne groups at the reducing end of CNC, which could be used as reaction sites for further click reactions.

Optimizing removal of antiretroviral drugs from tertiary wastewater using chlorination and AI-based prediction with response surface methodology.

Chemical and pharmaceutical chemicals found in water sources create substantial risks to human health and the environment. The presence of pharmaceutical contaminants in water can cause antibiotic resistance development, toxicity to aquatic organisms, and endocrine disruption. Hence, the elimination of chemicals and other contaminants from wastewater prior to its release is a burgeoning concern in the domains of engineering and science. The use of treatment technologies in wastewater treatment plants can remove pharmaceutical contaminants through the oxidation process. However, many traditional wastewater treatment plants lack the advanced monitoring tools required to detect low concentrations of pharmaceuticals. Without the ability to detect these compounds, it's challenging to treat them effectively. The goal of this study was to use Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) algorithms to model and improve how Nevirapine and Efavirenz break down in different chlorination conditions. The RSM analysis revealed statistically significant models (F-values: Nevirapine, pH-t: 108.15, T-t: 76.55, ICC-t: 110.84), indicating a strong correlation between operational parameters (pH, temperature, and initial chlorine concentration) and degradation behavior. The ANN model accurately predicted the degradation of both Nevirapine and Efavirenz under various chlorination conditions, as confirmed by analyzing actual-predicted graphs, residual plots, and Mean Squared Error (MSE) values. The ANN model using ICC-t achieved the highest MOD value of 31.31 % for Nevirapine. The ANN model based on ICC-t yielded a maximum MOD value of 16.06 % for Efavirenz. These findings provide valuable insights into optimizing chlorination processes for better removal of these pharmaceutical contaminants from water.

Adsorption of antiretroviral drugs, abacavir, nevirapine, and efavirenz from river water and wastewater using exfoliated graphite: Isotherm and kinetic studies.

In this work, exfoliated graphite was used to adsorb antiretroviral drugs from river water and wastewater. The exfoliated graphite was prepared from natural graphite by intercalating it with the acids and exfoliating it at 800 °C. It was characterized using Fourier Transform Infrared Spectroscopy which showed phenolic, alcoholic, and carboxylic functional groups between 1000 cm-1 and 1700 cm-1. Energy-dispersive X-ray spectroscopy results showed carbon as the main element with splashes of oxygen. The Scanning Electron Microscopy images showed increased c-axis distance between graphene layers after intercalation, which further increased after the exfoliation. The exfoliation resulted in elongated distorted cylinders, which were confirmed by the lower density (0.0068 g/mL) of exfoliated graphite material compared to the natural graphite (0.54 g/mL). The X-ray diffraction pattern showed the characteristics of hexagonal phase graphitic structure by the diffraction plane (002) at 26.74°. Raman spectroscopy results showed the natural graphite, graphite intercalated, and exfoliated graphite contained the D, G, D', and G' peaks at about 1350 cm-1, 1570 cm-1, 2440 cm-1, and 2720 cm-1, respectively indicating that the material's crystallinity was not affected by the modification. The highest antiretroviral drugs removal (95-99%), from the water was achieved with a solution pH of 7, an adsorbent mass of 30 mg, and an adsorption time of 30 min. The kinetic model and adsorption isotherm studies showed that the experimental data fit well in pseudo-second-order kinetics and is well explained by Freundlich's adsorption isotherm. The maximum adsorption capacity of the exfoliated graphite for antiretroviral drugs ranges between 1.660 and 197.0, 1.660-232.5, and 1.650-237.7 mg/g for abacavir, nevirapine, and efavirenz, respectively. The obtained removal percentages were 100% in river water, 63-100% in influent and 70-100% in effluent wastewater unspiked samples.

Super-Resolution Imaging of Clickable Lipids With Lipid Expansion Microscopy (LExM).

Fluorescent imaging of cellular membranes is challenged by the size of lipid bilayers, which are smaller than the diffraction limit of light. Recently, expansion microscopy (ExM) has emerged as an approachable super-resolution method that requires only widely accessible confocal microscopes. In this method, biomolecules of interest are anchored to hydrogel-based, polymeric networks that are expanded through osmosis to physically separate and resolve features smaller than the diffraction limit of light. Whereas ExM has been employed for super-resolution imaging of proteins, DNA, RNA, and glycans, the application of this method to the study of lipids is challenged by the requirement of permeabilization procedures that remove lipids and compromise the integrity of the membrane. Here, we describe our recently developed protocols for lipid expansion microscopy (LExM), a method that enables ExM of membranes without permeabilization. These detailed protocols and accompanying commentary sections aim to make LExM accessible to any experimentalist interested in imaging membranes with super-resolution. © 2024 Wiley Periodicals LLC. Basic Protocol 1: LExM of alkyne-choline lipids Basic Protocol 2: LExM of IMPACT-labeled lipids Basic Protocol 3: LExM of clickable cholesterol Basic Protocol 4: Determining the expansion factor.

[Liver impairment status toward workers exposed to vinyl chloride under different techniques].

OBJECTIVE: To analyse potential differences towards liver impairment status on vinyl chloride monomer(VCM) exposed population from technique under acetylene hydrochlorination to the one of ethylene oxychlorination respectively and to explore the possible reasons, which will pave the way for occupational health promotion in terms of hazard reduction. METHODS: a cross-sectional study was initiated between June and September in 2022 towards 2 groups of VCM exposed population from the facility of acetylene hydrochlorination(n=78) and the one of ethylene oxychlorination(n=69) in a PVC petrochemical complex enterprise(abbreviation of H) in Tianjin City. The demographic information concerning age, gender, messages on occupational history, field investigation were inquired through questionnaire interview. Then, venous blood(4 mL/person) and urine(10-50 mL/person) were collected during the physical exam phase and indices of 8-hydroxy-2 deoxyguanosine(8-OHdG) in blood and thiodiglycolic acid(TDGA) in urine were detected through ELISA and solid phase extraction-ion chromatography respectively. RESULTS: The 2 groups of population were matched well in terms of average age distribution and gender composition ratio, with significant differences on population composition ratio were found on variables of working years, alcohol consumption and daily sleeping duration(P<0.01 or P<0.05). It was found that the average content of TDGA in acetylene hydrochlorination group was(0.81±0.05)mg/L while the content in ethylene oxychlorination group reached to(0.83±0.06)mg/L, noteworthy differences were only found among 6 posts in the acetylene hydrochlorination group and 5 others in the ethylene oxychlorination group after classification for specific posts, however, the average concentration of 8-OHdG in acetylene hydrochlorination group(122(78.3, 168.8) µg/m~3) was different from the one in ethylene oxychlorination group(101.7(79.6, 149.7) µg/m~3)(Z=6.82, P<0.05). Moreover, a series of positive correlations in moderate intensity between 8-OHdG concentration and TDGA content were observed among posts of polymerization cleaners(r=0.53), aggregation operators(r=0.47), maintenance repairers(r=0.45), sampling operators(r=0.41) in acetylene hydrochlorination group(P<0.05) and posts of cracking reactants(r=0.64), DCS operators(r=0.51), oxychlorination operators(r=0.50) and chemical loaders(r=0.44) in ethylene oxychlorination group(P<0.05). Liver function indices such as content on ALT(χ~2=15.41, P<0.01), AST(χ~2=9.95, P<0.01) and ALP(χ~2=3.79, P<0.01) were different in the 2 groups population with statistical significance, then proportions on population composition ratio that exceeded normal ranges of indices on ALT, AST, AST/ALT ratio, ALP and Alb/Glb ratio were higher in acetylene hydrochlorination group than ones in ethylene oxychlorination group with great significance(P<0.05), so as to the abnormalities in liver B altrosonography test between groups(χ~2=17.33, P<0.01). Binary logistic regression model indicated that 8-OHdG concentration in blood that exceed 90 µg/m~3, TDGA content in urine that exceed 0.60 mg/L, working years that were over 10a, alcohol consumption, sleeping duration less than 6 h per day and male workers were potential risky factors for liver impairment(P<0.05). CONCLUSION: The degree on liver impairment status was higher in acetylene hydrochlorination group than ones in in ethylene oxychlorination group under the same PVC factory, which might be associated with the oxidative stress injury induced from the combination of higher VCM concentration at workplaces, longer cumulative exposure time, longer working years, alcohol consumption habits and sleep shortage caused by shift work patterns.

Alkyne-tagged SERS nanoprobe for understanding Cu+ and Cu2+ conversion in cuproptosis processes.

Simultaneously quantifying mitochondrial Cu+ and Cu2+ levels is crucial for evaluating the molecular mechanisms of copper accumulation-involved pathological processes. Here, a series of molecules containing various diacetylene derivatives as Raman reporters are designed and synthesized, and the alkyne-tagged SERS probe is created for determination Cu+ and Cu2+ with high selectivity and sensitivity. The developed SERS probe generates well-separated distinguishable Raman fingerprint peaks with built-in corrections in the cellular silent region, resulting in accurate quantification of Cu+ and Cu2+. The present probe demonstrates high tempo-spatial resolution for real-time imaging and simultaneously quantifying mitochondrial Cu+ and Cu2+ with long-term stability benefiting from the probe assembly with designed Au-C≡C groups. Using this powerful tool, it is found that mitochondrial Cu+ and Cu2+ increase during ischemia are associated with breakdown of proteins containing copper as well as conversion of Cu+ and Cu2+. Meanwhile, we observe that parts of Cu+ and Cu2+ are transported out of neurons by ATPase. More importantly, cuproptosis in neurons is found including the oxidative stress process caused by the conversion of Cu+ to Cu2+, which dominates at the early stage (<9 h), and subsequent proteotoxic stress. Both oxidative and proteotoxic stresses contribute to neuronal death.

Disproof of the Structures and Biosynthesis of Ergoynes, Gs-Polyyne-l-Ergothioneine Cycloadducts from Gynuella sunshinyii YC6258.

Some bacteria produce "bacterial polyynes" bearing a conjugated C≡C bond that starts with a terminal alkyne. Ergoynes A and B have been reported as sulfur-containing metabolites from Gynuella sunshinyii YC6258. These compounds were thought to be formed by cycloaddition between a bacterial polyyne (named Gs-polyyne) and l-ergothioneine. The biosynthetic gene clusters (BGCs), which may contribute to their synthesis, were present in the YC6258 genome. The biosynthetic origin of Gs-polyyne is interesting considering its rare 2-isopentyl fatty acyl skeleton. Here, the structures and biosynthesis of Gs-polyyne and ergoynes were verified by analytical, chemical, and genetic techniques. In the YC6258 extract, which was prepared considering their instability, Gs-polyyne was detected as a major LC peak, and ergoynes were not detected. The NMR data of the isolated Gs-polyyne contradicted the proposed structure and identified it as the previously reported protegenin A. The expression of Gs-polyyne BGC in Escherichia coli BL21(DE3) also yielded protegenin A. The cyclization between protegenin A and l-ergothioneine did not proceed during sample preparation; a base, such as potassium carbonate, was required. Overall, Gs-polyyne was identified as protegenin A, while ergoynes were determined to be artifacts. This cyclization may provide a derivatization to stabilize polyynes or create new chemical space.

Removal of antiretroviral drugs from wastewater using activated macadamia nutshells: Adsorption kinetics, adsorption isotherms, and thermodynamic studies.

Antiretroviral drugs (ARVDs) have been extensively employed in health care to improve the quality of life and lifecycle longevity. However, overuse and improper disposal of ARVDs have been recognized as an emerging concern whereby wastewater treatment major recipients. Therefore, in this work, the activated macadamia nutshells (MCNs) were explored as low-cost adsorbents for the removal of ARVDs in wastewater samples. Fourier transform infrared spectroscopy (FTIR), Scanning Electron microscopy (SEM), Brunauer-Emmet-Teller (BET), and Powder X-ray diffraction (PXRD). The highest removal efficiency (R.E) was above 86% for the selected analytes nevirapine, abacavir, and efavirenz. The maximum adsorption capacity of the functionalized MCN adsorbent was 10.79, 27.44, and 38.17 mg/g for nevirapine, abacavir, and efavirenz for HCl-modified adsorbent. In contrast, NaOH modified had adsorption capacities of 13.67, 14.25, and 20.79 mg/g. The FTIR showed distinct functional groups OH and CO, which facilitate the removal of selected ARVDs. From studying kinetics parameters, the pseudo-second-order (R2 = 0.990-0.996) was more dominant than the pseudo-first-order (R2 = 0.872-0.994). The experimental data was most fitted in the Freundlich model with (R2 close to 1). The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. The study indicated that MCNs are an eco-friendly, low-cost, and effective adsorbent for the removal of nevirapine, abacavir, and efavirenz. PRACTITIONER POINTS: Modification macadamia nutshell with HCl and NaOH improved physio-chemical properties that yielded high removal efficiency compared with raw macadamia nutshells. Modification of macadamia by HCl showed high removal efficiency, which could be attributed to high interaction such as H-bonding that improves adsorption. The macadamia nutshell as an adsorbent showed so much robustness with regeneration studies yielding to about 69.64% of selected compounds.

Transfer Hydrogenation of Vinyl Arenes and Aryl Acetylenes with Ammonia Borane Catalyzed by Schiff Base Cobalt(II) Complexes.

A series of bench-stable Co(II) complexes containing hydrazone Schiff base ligands were evaluated in terms of their activity and selectivity in carbon-carbon multiple bond transfer hydrogenation. These cobalt complexes, especially a Co(II) precatalyst bearing pyridine-2-yl-N(Me)N=C-(1-methyl)imidazole-2-yl ligand, activated by LiHBEt3, were successfully used in the transfer hydrogenation of substituted styrenes and phenylacetylenes with ammonia borane as a hydrogen source. Key advantages of the reported catalytic system include mild reaction conditions, high selectivity and tolerance to functional groups of substrates.

The use of suboptimal antiretroviral therapy when applying for migration to Australia: a case series.

Background Australia imposes restrictions for people living with HIV (PLHIV) applying for permanent residency (PR), including spending less than AUD51,000 on medical costs over 10years. Some PLHIV opted for suboptimal and cheaper antiretroviral therapy (ART) regimens to increase their chances of receiving PR. We collated a case series to examine PLHIV on suboptimal ART because of visa issues. Methods We identified all patients applying for a PR in Australia who obtained nevirapine, efavirenz or zidovudine between July 2022 and July 2023 from the Melbourne Sexual Health Centre. Pathology results and records detailing psychological issues relating to the patients' wishes to remain on suboptimal ART were extracted from clinical records by two researchers. Results We identified six patients with a mean age of 39years migrating from Asian and European countries. Three patients used efavirenz, and three used nevirapine. All desired to remain on cheaper, suboptimal ART to stay below visa cost thresholds, which they considered to aid favourably with their application. Four displayed stress and anxiety arising from visa rejections, appeal deadlines and the lengthy visa application process. Conclusions Despite access to more effective and safer ART, we identified patients who chose to remain on cheaper ART to improve chances of obtaining an Australian visa, potentially putting their health at risk. We found significant evidence of stress and anxiety among patients. There is a need to review and revise current migration policies and laws in Australia that discriminate against PLHIV and jeopardise public health.

Site-Specific Conjugation of Bottlebrush Polymers to Therapeutic Protein via Bioorthogonal Chemistry.

Achieving efficient and site-specific conjugation of therapeutic protein to polymer is crucial to augment their applicability in the realms of biomedicine by improving their stability and enzymatic activity. In this study, we exploited tetrazine bioorthogonal chemistry to achieve the site-specific conjugation of bottlebrush polymers to urate oxidase (UOX), a therapeutic protein for gout treatment. An azido-functionalized zwitterionic bottlebrush polymer (N3-ZBP) using a "grafting-from" strategy involving RAFT and ATRP methods was synthesized, and a trans-cyclooctene (TCO) moiety was introduced at the polymer end through the strain-promoted azide-alkyne click (SPAAC) reaction. The subsequent coupling between TCO-incorporated bottlebrush polymer and tetrazine-labeled UOX using a fast and safe bioorthogonal reaction, inverse electron demand Diels-Alder (IEDDA), led to the formation of UOX-ZBP conjugates with a 52% yield. Importantly, the enzymatic activity of UOX remained unaffected following polymer conjugation, suggesting a minimal change in the folded structure of UOX. Moreover, UOX-ZBP conjugates exhibited enhanced proteolytic resistance and reduced antibody binding, compared to UOX-wild type. Overall, the present findings reveal an efficient and straightforward route for synthesizing protein-bottlebrush polymer conjugates without compromising the enzymatic activity while substantially reducing proteolytic degradation and antibody binding.

A validated method for simultaneous quantification of four antiretrovirals in dried blood spot and plasma using LC-MS/MS: Application to efavirenz therapeutic drug monitoring in pregnant patients.

INTRODUCTION: The specific physiological background induced by pregnancy leads to significant changes in maternal pharmacokinetics, suggesting potential variability in plasma concentrations of antiretrovirals. Pregnant HIV patients exposed to subtherapeutic doses, particularly in the last trimester of the pregnancy, have higher chances to transmit the infection to their children. Therefore, the therapeutic drug monitoring of antiretrovirals in HIV pregnant patients would be of great value. OBJECTIVES: This study aimed to develop and validate a sensitive liquid chromatograph tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of efavirenz, raltegravir, atazanavir, and ritonavir in dried blood spots (DBS) and plasma. DESIGN AND METHODS: The analytes were extracted from the DBS punch and plasma with a mixture of methanol:zinc sulfate 200 mM (50:50, v/v) and 100 % methanol, respectively. For the chromatographic separation a Shim-pack® C18, 4.6 mm × 150 mm, 5 µm column was used. Detection was performed in a 3200-QTRAP® mass spectrometer, with a run time of 6 min. RESULTS: The assay was linear in the range of 15-1,000 ng/mL for raltegravir, 50-10,000 ng/mL for both atazanavir and ritonavir, 50-5,000 ng/mL for efavirenz. Precision and accuracy at these concentrations were less than 15 % for all analytes. Raltegravir, atazanavir, and ritonavir were stable for seven days at 23 °C and 40 °C, whereas efavirenz was stable for twenty-four hours at the same conditions. CONCLUSIONS: The method was successfully applied to quantify efavirenz in DBS samples obtained from HIV-1 infected pregnant volunteers under antiretroviral therapy. The concentrations of efavirenz in DBS and plasma were comparable according to Passing-Bablok regression and Bland-Altman analysis.

Visual Detection of LPS at the Femtomolar Level Based on Click Chemistry-Induced Gold Nanoparticles Electrokinetic Accumulation.

Lipopolysaccharide (LPS) presents a significant threat to human health. Herein, a novel method for detecting LPS was developed by coupling hybridization chain reaction (HCR), gold nanoparticles (AuNPs) agglutination (AA) triggered by a Cu(I)-catalyzed azide-alkyne cycloaddition click chemistry (CuAAC), and electrokinetic accumulation (EA) in a microfluidic chip, termed the HCR-AA-EA method. Thereinto, the LPS-binding aptamer (LBA) was coupled with the AuNP-coated Fe3O4 nanoparticle, which was connected with the polymer of H1 capped on CuO (H1-CuO) and H2-CuO. Upon LPS recognition by LBA, the polymers of H1- and H2-CuO were released into the solution, creating a "one LPS-multiple CuO" effect. Under ascorbic acid reduction, CuAAC was initiated between the alkyne and azide groups on the AuNPs' surface; then, the product was observed visually in the microchannel by EA. Finally, LPS was quantified by the integrated density of AuNP aggregates. The limit of detections were 29.9 and 127.2 fM for water samples and serum samples, respectively. The levels of LPS in the injections and serum samples by our method had a good correlation with those from the limulus amebocyte lysate test (r = 0.99), indicating high accuracy. Remarkably, to popularize our method, a low-cost, wall-power-free portable device was developed, enabling point-of-care testing.

Integrated study of antiretroviral drug adsorption onto calcined layered double hydroxide clay: experimental and computational analysis.

This study focused on the efficacy of a calcined layered double hydroxide (CLDH) clay in adsorbing two antiretroviral drugs (ARVDs), namely efavirenz (EFV) and nevirapine (NVP), from wastewater. The clay was synthesized using the co-precipitation method, followed by subsequent calcination in a muffle furnace at 500 °C for 4 h. The neat and calcined clay samples were subjected to various characterization techniques to elucidate their physical and chemical properties. Response surface modelling (RSM) was used to evaluate the interactions between the solution's initial pH, adsorbent loading, reaction temperature, and initial pollutant concentration. Additionally, the adsorption kinetics, thermodynamics, and reusability of the adsorbent were evaluated. The results demonstrated that NVP exhibited a faster adsorption rate than EFV, with both reaching equilibrium within 20-24 h. The pseudo-second order (PSO) model provided a good fit for the kinetics data. Thermodynamics analysis revealed that the adsorption process was spontaneous and exothermic, predominantly governed by physisorption interactions. The adsorption isotherms followed the Freundlich model, and the maximum adsorption capacities for EFV and NVP were established to be 2.73 mg/g and 2.93 mg/g, respectively. Evaluation of the adsorption mechanism through computational analysis demonstrated that both NVP and EFV formed stable complexes with CLDH, with NVP exhibiting a higher affinity. The associated adsorption energies were established to be -731.78 kcal/mol for NVP and -512.6 kcal/mol for EFV. Visualized non-covalent interaction (NCI) graphs indicated that hydrogen bonding played a significant role in ARVDs-CLDH interactions, further emphasizing physisorption as the dominant adsorption mechanism.