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Herein, we present the design and fabrication of a portable biochemical sensor based on the Screen Printed Electrode (SPE) concept and applied for detecting interleukin-6 (IL-6), a key player in the complex process of inflammation, in real human saliva. The sensing mechanism relies on the antigen-antibody binding between the IL-6 molecule and its antibody immobilized over a surface of a Thermally Exfoliated Graphene Oxide (TEGO) layer. TEGO, deposited by Aerosol Jet Printing (AJP), provides advantages in terms of a time/cost consumingfast, easy and efficient biofunctionalization. The biosensor shows a dynamic range comprising IL-6 concentrations falling within the normal IL-6 levels in saliva. An extensive analysis of device performance, focused on the assessment of the sensor Limit of Detection (LoD) by two modes (i.e. from the lin-log calibration curve and from blank measurements), provides a best value of about 1 × 10−2 pg/ml of IL-6 in saliva. Our work aims at providing a contribution toward applications in real environment, going beyond a proof of concept or prototyping at lab scale. Hence, the characterization of the sensor was finalized to find a reliable device-to-device reproducibility and calibration through the introduction of a measurement protocol based on comparative measurements between saliva samples without (blank) and with IL-6 spiked in it, in place of the standard addition method used in daily laboratory practice. Device-to-device reproducibility has been accordingly tested by acquiring multiple experimental points along the calibration curve using different individual devices for each point.

Simple Summary: Livestock predation fuels conflicts between humans and wildlife, leading to the killing of wild animals such as Andean bears, jaguars, and pumas. Despite wild predators being blamed, domestic dogs also harm livestock and spread diseases among animals and people, affecting nature, local livelihoods, food, and our well-being, the very goals the United Nations aims to safeguard by 2030. In Ecuador, where families depend on livestock, retaliatory hunting jeopardizes the survival of wildlife. However, the role of dogs in these conflicts remains unclear. This study analyzed DNA found on bite wounds, revealing traces of dog saliva on animals presumed to be attacked by wild predators. This discovery challenges misconceptions about these animals in Ecuador and emphasizes the need to manage dog populations more effectively. To address this issue, we propose incorporating DNA tests in livestock predation cases to assess the involvement of dogs accurately. By understanding the true causes, strategies can be devised to mitigate these conflicts, preserving the vital role of these important animals in our ecosystem. Livestock predation induces global human–wildlife conflict, triggering the retaliatory killing of large carnivores. Although domestic dogs (Canis familiaris) contribute to livestock depredation, blame primarily falls on wild predators. Dogs can also transmit pathogens between wildlife, domestic animals, and humans. Therefore, the presence of free-ranging dogs can have negative consequences for biodiversity conservation, smallholder economy, food supply, and public health, four of the United Nations' Sustainable Developed Goals (SDGs) for 2030. In Ecuador, where livestock sustains rural households, retaliatory poaching threatens Andean bear (Tremarctos ornatus), jaguar (Panthera onca), and puma (Puma concolor) populations. However, the role of dogs in these incidents remains underexplored. The present study evaluates the possibility of reliable molecular identification of predatory species from DNA traces in bite wounds. Our results revealed the presence of dog saliva on four out of six livestock carcasses presumably attacked by wild predators. These findings highlight the importance of rectifying misinformation about large carnivores in Ecuador and the need to control dog populations. We recommend that local administrations incorporate DNA analysis into livestock predation events to examine how common the problem is, and to use the analysis to develop conflict mitigation strategies which are essential for the conservation of large carnivores. [ABSTRACT FROM AUTHOR]

Livestock predation induces global human–wildlife conflict, triggering the retaliatory killing of large carnivores. Although domestic dogs (Canis familiaris) contribute to livestock depredation, blame primarily falls on wild predators. Dogs can also transmit pathogens between wildlife, domestic animals, and humans. Therefore, the presence of free-ranging dogs can have negative consequences for biodiversity conservation, smallholder economy, food supply, and public health, four of the United Nations’ Sustainable Developed Goals (SDGs) for 2030. In Ecuador, where livestock sustains rural households, retaliatory poaching threatens Andean bear (Tremarctos ornatus), jaguar (Panthera onca), and puma (Puma concolor) populations. However, the role of dogs in these incidents remains underexplored. The present study evaluates the possibility of reliable molecular identification of predatory species from DNA traces in bite wounds. Our results revealed the presence of dog saliva on four out of six livestock carcasses presumably attacked by wild predators. These findings highlight the importance of rectifying misinformation about large carnivores in Ecuador and the need to control dog populations. We recommend that local administrations incorporate DNA analysis into livestock predation events to examine how common the problem is, and to use the analysis to develop conflict mitigation strategies which are essential for the conservation of large carnivores.

Polyvalent mechanical bacterial lysate is effective in the prevention of respiratory tract infections, although its mechanism of action is not entirely elucidated. Because epithelial cells constitute the frontline defense against infections, we investigated the molecular mechanisms of innate response exerted by bronchial epithelial cells in the presence of polyvalent mechanical bacterial lysate. By using primary human bronchial epithelial cells, we observed that polyvalent mechanical bacterial lysate was able to increase the expression of cellular adhesion molecules such as ICAM-1 and E-cadherin, as well as the expression of amphiregulin, a growth factor able to support human bronchial epithelial cell proliferation. Remarkably, polyvalent mechanical bacterial lysate promoted in human bronchial epithelial cells the de novo expression of human β-defensin-2, a major antimicrobial peptide, conferring them a direct antimicrobial activity. Moreover, polyvalent mechanical bacterial lysate–stimulated human bronchial epithelial cells provided signals for increased IL-22 production by innate lymphoid cells via IL-23, which could further contribute to the release of antimicrobial peptides by epithelial cells. In agreement with these in vitro data, the concentration of both IL-23 and antimicrobial peptides (human β-defensin-2 and LL-37) increased in the saliva of healthy volunteers after sublingual administration of polyvalent mechanical bacterial lysate. Altogether, these results indicate that polyvalent mechanical bacterial lysate administration might support mucosal barrier integrity and promote mechanisms of antimicrobial activity in airway epithelial cells. [ABSTRACT FROM AUTHOR]

Saliva is one of the most significant biological liquids for the development of a simple, rapid, and non-invasive biosensor for training load diagnostics. There is an opinion that enzymatic bioassays are more relevant in terms of biology. The present paper is aimed at investigating the effects of saliva samples, upon altering the lactate content, on the activity of a multi-enzyme, namely lactate dehydrogenase + NAD(P)H:FMN-oxidoreductase + luciferase (LDH + Red + Luc). Optimal enzymes and their substrate composition of the proposed multi-enzyme system were chosen. During the tests of the lactate dependence, the enzymatic bioassay showed good linearity to lactate in the range from 0.05 mM to 0.25 mM. The activity of the LDH + Red + Luc enzyme system was tested in the presence of 20 saliva samples taken from students whose lactate levels were compared by the Barker and Summerson colorimetric method. The results showed a good correlation. The proposed LDH + Red + Luc enzyme system could be a useful, competitive, and non-invasive tool for correct and rapid monitoring of lactate in saliva. This enzyme-based bioassay is easy to use, rapid, and has the potential to deliver point-of-care diagnostics in a cost-effective manner. [ABSTRACT FROM AUTHOR]

To compare the detection of the SARS-CoV-2 Omicron variant in nasopharyngeal-swab (NPS) and oral saliva samples. 255 samples were obtained from 85 Omicron-infected patients. SARS-CoV-2 load was measured in the NPS and saliva samples by using Simplexa™ COVID-19 direct and Alinity m SARS-CoV-2 AMP assays. Results obtained with the two diagnostic platforms showed very good inter-assay concordance (91.4 and 82.4% for saliva and NPS samples, respectively) and a significant correlation among cycle threshold (Ct) values. Both platforms revealed a highly significant correlation among Ct obtained in the two matrices. Although the median Ct value was lower in NPS than in saliva samples, the Ct drop was comparable in size for both types of samples after 7 days of antiviral treatment of the Omicron-infected patients. Our result demonstrates that the detection of the SARS-CoV-2 Omicron variant is not influenced by the type of sample used for PCR analysis, and that saliva can be used as an alternative specimen for detection and follow-up of Omicron-infected patients. [ABSTRACT FROM AUTHOR]

The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic demanded rapid diagnosis to isolate new COVID-19 cases and prevent disease transmission. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) rapidly became the gold standard for diagnosis. However, due to the high cost and delay of the results, other types of diagnosis were implemented, such as COVID-19 Ag Rapid Tests and Reverse Transcription Technique followed by Loop-Mediated isothermal Amplification (RT-LAMP). In this work, we validated the use of RT-LAMP in saliva samples rather than nasopharyngeal swabs, as the collection is more comfortable. First, we selected 5 primer sets based on the limit of detection for SARS-CoV-2 RNA, then validated their sensitivity and specificity in patient samples. A total of 117 samples were analyzed by fluorometric RT-LAMP and compared with qRT-PCR results. Our results show that the use of a high-sensitive primer ORF1-a, together with a low-sensitive primer set Gene E (time to threshold of 22.9 and 36.4 minutes, respectively, using 200 copies of viral RNA), achieved sensitivity in purified RNA from saliva samples of 95.2% (95% CI 76.1‒99.8) with 90.5% specificity (95% CI 69.6‒98.8) (n = 42).As RNA purification increases the turnaround time, we tested the outcome of RT-LAMP utilizing raw saliva samples without purification. The test achieved a sensitivity of 81.8% (95% CI 59.7‒94.8) and a specificity of 90.9% (95% CI 70.8‒98.8). As a result, the accuracy of 92.9% (95% CI 80.5‒98.5) in purified RNA-saliva samples was lowered to an acceptable level of 86.4% (95% CI 72.6‒94.8) in raw saliva. Although mass vaccination has been implemented, new strains and low vaccination progress helped to spread COVID-19. This study shows that it is feasible to track new COVID-19 cases in a large population with the use of raw saliva as sample in RT-LAMP assay which yields accurate results and offers a less invasive test.

A novel, rapid, and facile method for the colorimetric determination of calcium using micro-analytical paper-based devices (μ-PADs) was developed. The proposed analytical method utilizes the color differences developing, after the addition of calcium, on the surface of the devices because of the complexation reaction of calcium with Methylthymol Blue (MTB) at room temperature, in alkaline pH. The devices were manufactured with chromatographic paper, using wax barriers, and the analytical protocol was easily implemented without the need of any experimental apparatus except for a simple imaging device. The user must regulate the pH, add the solutions on the paper, and measure the color intensity of the formed Ca(II)–MTB complex with a flatbed scanner. The experimental conditions for optimum color development, the possible interfering substances, and the reliability of the paper devices in different preserving conditions were optimized, with satisfactory results. The method exhibited acceptable detection limits (2.9 mg L−1) with sufficiently good precision, which varied from 4.2% (intra-day) to 6.4% (inter-day). Saliva samples from healthy volunteers were successfully analyzed, and the calcium levels were calculated in the range of 30.71 to 84.15 mg L−1. [ABSTRACT FROM AUTHOR]

Objectives: To describe the trend of SARS-CoV-2 RNA in saliva samples from children attending nine schools in Rome in the local surveillance unit RM3 during the period of September 2021-March 2022, in parallel with the trend of SARS-CoV-2 RNA observed in nasopharyngeal swabs (NPSs) from the population in the same catchment area that was routinely tested at our laboratory in the same period. Methods: Saliva samples were collected using the Copan LolliSpongeTM device and analyzed by Aptima® SARS-CoV-2 Assay on the Panther® System. NPSs were tested using either Aptima® SARS-CoV-2 Assay or Alinity m SARS-CoV-2 Assay. Results: The percentage of positivity in the two populations was different; of the 2222 saliva samples from students, 0.99% had positive results, whereas the percentage was higher (33.43%) in the 8994 NPSs representing the population from local surveillance unit RM3. Interestingly, the trend of SARS-CoV-2 RNA in saliva samples from students was consistent with that observed in NPSs from the population in same catchment area, although with peaks slightly anticipated. Conclusion: Overall, screening of saliva in the schools represents a good system to monitor SARS-CoV-2 circulation in the population, allowing early detection and quick isolation of students who are asymptomatic with positive test results and thus prevention of virus transmission.

In this work, a microfluidic paper-based analytical device (μPAD) was developed for magnesium determination in saliva samples. The idea was to develop a fast and simple method for biological magnesium quantification targeting saliva as an easy to collect and non-invasive alternative to blood or urine samples. The μPAD approach was chosen due to its advantages, namely ideally suited to conduct on-location determinations, and not requiring trained operators or specialized laboratory equipment. The developed μPAD was based on the colorimetric reaction between eriochrome cyanine and magnesium to form an intense orange/reddish colour product. The colour intensity was determined by image processing after digital scanning, made within 10 to 90 min after sample loading. Under optimal conditions, the dynamic concentration range was 82–247 μM, with detection and quantification limits of 62 μM and 81 μM, respectively. The device is stable for up to 3 months when stored in vacuum or in a modified nitrogen atmosphere. An accuracy assessment was made by comparing the results obtained using the developed μPAD with those from atomic absorption spectrometry (AAS). The relative difference between the two sets of results was below 5%.

Head and neck squamous cell carcinomas (HNSCCs) are linked to tobacco smoking, opium use, and human papillomavirus (HPV) infection. However, little is known about the association of HPV infection with risk factors of HNSCCs, including opium and tobacco use. This cross-sectional analysis of a national multi-center case-control study in Iran included 498 HNSCC cases and 242 controls. We investigated the association of opium and tobacco use with α- (n = 21), β- (n = 46), and γ-HPV (n = 52) types in saliva samples using type-specific bead-based multiplex genotyping assays (TS-MPG). We found that α-HPV positivity was significantly associated with tobacco smoking (OR = 10.35; 95% CI = 1.15, 93; p = .03), but not with opium use (OR = 1.06; 95% CI = 0.41, 2.76; p = .89). Additionally, tobacco smoking correlated with an elevated risk of β-species 2 HPV infection (OR = 1.28; 95% CI = 1.04, 1.58; p = .020). Conversely, opium use showed a positive association with γ-species 12 HPV infection (OR = 5.67; 95% CI = 1.43, 22.44; p = .013). These findings indicate that tobacco and opium use may influence the risk of HPV infection in different ways depending on the HPV genus and species. Further studies are needed to replicate these findings in other populations., (© 2024 UICC.)

To compare the detection of the SARS-CoV-2 Omicron variant in nasopharyngeal-swab (NPS) and oral saliva samples. 255 samples were obtained from 85 Omicron-infected patients. SARS-CoV-2 load was measured in the NPS and saliva samples by using Simplexa™ COVID-19 direct and Alinity m SARS-CoV-2 AMP assays. Results obtained with the two diagnostic platforms showed very good inter-assay concordance (91.4 and 82.4% for saliva and NPS samples, respectively) and a significant correlation among cycle threshold (Ct) values. Both platforms revealed a highly significant correlation among Ct obtained in the two matrices. Although the median Ct value was lower in NPS than in saliva samples, the Ct drop was comparable in size for both types of samples after 7 days of antiviral treatment of the Omicron-infected patients. Our result demonstrates that the detection of the SARS-CoV-2 Omicron variant is not influenced by the type of sample used for PCR analysis, and that saliva can be used as an alternative specimen for detection and follow-up of Omicron-infected patients.

Saliva is one of the most significant biological liquids for the development of a simple, rapid, and non-invasive biosensor for training load diagnostics. There is an opinion that enzymatic bioassays are more relevant in terms of biology. The present paper is aimed at investigating the effects of saliva samples, upon altering the lactate content, on the activity of a multi-enzyme, namely lactate dehydrogenase + NAD(P)H:FMN-oxidoreductase + luciferase (LDH + Red + Luc). Optimal enzymes and their substrate composition of the proposed multi-enzyme system were chosen. During the tests of the lactate dependence, the enzymatic bioassay showed good linearity to lactate in the range from 0.05 mM to 0.25 mM. The activity of the LDH + Red + Luc enzyme system was tested in the presence of 20 saliva samples taken from students whose lactate levels were compared by the Barker and Summerson colorimetric method. The results showed a good correlation. The proposed LDH + Red + Luc enzyme system could be a useful, competitive, and non-invasive tool for correct and rapid monitoring of lactate in saliva. This enzyme-based bioassay is easy to use, rapid, and has the potential to deliver point-of-care diagnostics in a cost-effective manner.

A clinical trial is currently underway to examine the efficacy of using caffeine citrate to prevent intermittent hypoxemia in late preterm neonates. Determining caffeine concentration using saliva in this population would be preferable as it is less invasive than plasma sampling, but a suitable method of analysis is required. This paper presents the development and validation of a rapid, efficient and reproducible stability-indicating high-performance liquid chromatography (HPLC) method and extraction protocol for the quantification of caffeine present in saliva. The stability of extemporaneously prepared caffeine citrate solutions (at 20–25 °C) was determined, along with the stability of caffeine spiked saliva samples (at 20–25 and 2–8 °C), to ensure the suitability of the developed method in the analysis of clinical trial samples. Protein precipitation using acetonitrile ensured the complete removal of salivary proteins and resulted in extraction recovery of ≥95% for all samples. The HPLC assay following extraction was linear (R2>0.99) over the range 0.3–50 µg/mL (lower limit of quantification 0.3 µg/mL). The accuracy of the quality control samples was 94–100% and the relative standard deviation (RSD) was <7% for all samples. Caffeine-spiked saliva samples were stable for three freeze-and-thaw cycles pre-extraction and up to 72 hr post-extraction. The extraction and HPLC methods described were thus suitable for the analysis of clinical trial samples from the Latte Dosage Trial. All caffeine solutions were physically and chemically stable, with concentrations at the end of the three-month test period being within 4% of the baseline concentrations, indicating appropriateness for use as clinical trial medications. [ABSTRACT FROM AUTHOR]

A novel, rapid, and facile method for the colorimetric determination of calcium using micro-analytical paper-based devices (μ-PADs) was developed. The proposed analytical method utilizes the color differences developing, after the addition of calcium, on the surface of the devices because of the complexation reaction of calcium with Methylthymol Blue (MTB) at room temperature, in alkaline pH. The devices were manufactured with chromatographic paper, using wax barriers, and the analytical protocol was easily implemented without the need of any experimental apparatus except for a simple imaging device. The user must regulate the pH, add the solutions on the paper, and measure the color intensity of the formed Ca(II)–MTB complex with a flatbed scanner. The experimental conditions for optimum color development, the possible interfering substances, and the reliability of the paper devices in different preserving conditions were optimized, with satisfactory results. The method exhibited acceptable detection limits (2.9 mg L−1) with sufficiently good precision, which varied from 4.2% (intra-day) to 6.4% (inter-day). Saliva samples from healthy volunteers were successfully analyzed, and the calcium levels were calculated in the range of 30.71 to 84.15 mg L−1.

• Saliva testing is useful in community mass-screening programs. • Circulation of SARS-CoV-2 is low in primary and lower secondary schools in Rome. • Low circulation suggests a relatively low risk of being infected at school. • Similar trends of positivity are found in students' saliva and local surveillance unit RM3 population's nasopharyngeal swabs. • Screening in the schools allows monitoring of SARS-CoV-2 circulation. To describe the trend of SARS-CoV-2 RNA in saliva samples from children attending nine schools in Rome in the local surveillance unit RM3 during the period of September 2021-March 2022, in parallel with the trend of SARS-CoV-2 RNA observed in nasopharyngeal swabs (NPSs) from the population in the same catchment area that was routinely tested at our laboratory in the same period. Saliva samples were collected using the Copan LolliSpongeTM device and analyzed by Aptima® SARS-CoV-2 Assay on the Panther® System. NPSs were tested using either Aptima® SARS-CoV-2 Assay or Alinity m SARS-CoV-2 Assay. The percentage of positivity in the two populations was different; of the 2222 saliva samples from students, 0.99% had positive results, whereas the percentage was higher (33.43%) in the 8994 NPSs representing the population from local surveillance unit RM3. Interestingly, the trend of SARS-CoV-2 RNA in saliva samples from students was consistent with that observed in NPSs from the population in same catchment area, although with peaks slightly anticipated. Overall, screening of saliva in the schools represents a good system to monitor SARS-CoV-2 circulation in the population, allowing early detection and quick isolation of students who are asymptomatic with positive test results and thus prevention of virus transmission. [ABSTRACT FROM AUTHOR]

Direct mass spectrometry (MS) is an exciting strategy in bioanalysis, enabling rapid decision-making in different scenarios. Its application is usually hindered by matrix effects and the typically low concentration of the target compounds in the biofluids. In this sense, combining a previous sample preparation step minimizes or removes these shortcomings. This article describes sorptive tape-spray tandem mass spectrometry (STS-MS/MS) based on mixed-mode particles as a strategy to combine sample preparation and MS analysis in a single device. The technique uses a sorptive tape (ST) consisting of mixed-mode polymeric microparticles (combining ionic exchange and hydrophobic interactions) coated over aluminum foil in a spatial controlled way. The tapes act as the sorptive phases to isolate the analytes from the sample matrix and substrates for STS-MS/MS. The performance of the technique has been evaluated by developing a method to determine codeine in saliva as proof of concept. The affordability of the STs elements allows the preparation of many individual phases at low cost so that several samples can be extracted simultaneously, thus increasing the sample throughput. The extraction variables were optimized following a multivariate approach. Working under the optimum conditions, the limit of detection was 0.3 μg L−1, while the intraday precision, calculated as relative standard deviation (RSD) at three concentration levels, was better than 9.4 %. The accuracy, expressed as relative recovery, was in the range of 78–98 %. The method was also applied to the analysis of real samples. Despite being a powerful strategy, the direct combination of microextraction to MS is not always affordable in all laboratories. For this reason, the STs were also combined with commercial liquid chromatography-MS working under the direct infusion mode to demonstrate the usefulness of the ST in classical extraction workflows. [Display omitted] • Mixed mode ionic exchange sorptive tapes (STs) are proposed for microextraction. • STs are directly coupled to mass spectrometry (MS) by sorptive tape-spray MS. • STs stand out for their rapid and cost-effective preparation, and high extraction capacity. • Codeine determination was demonstrated as proof of concept in real saliva samples. [ABSTRACT FROM AUTHOR]

• A new MSPE methodology has been developed for the simultaneously determination of Fingolimod (FIN) and Citalopram (CIT). • The magnetic sorbent including Fe 3 O 4 @L-Tyrosine of MSPE has been synthesized and characterized first times. • Simultaneous and Simple Analysis of FIN and CIT was performed at trace level first times. • The method was successfully applied to determination of target molecules in urine and saliva samples. An analytical methodology has been developed for trace amounts of Fingolimod (FIN) and Citalopram (CIT) drug molecules based on magnetic solid phase extraction (MSPE) and high performance liquid chromatographic determination with photodiode array detector (HPLC-DAD). Fingolimod is used in treatment of Multiple sclerosis (MS) disease and sometimes antidepressant drugs such as citalopram accompany to treatment. Both simultaneous analysis of these molecules and application of MSPE with a new adsorbent has been performed for first times. Fe 3 O 4 @L-Tyrosine magnetic particles has been synthetized and characterized as a new magnetic adsorbent. Experimental variables of MPSE were examined and optimized step by step such as pH, adsorption and desorption conditions, time effect, etc. Analytical parameters of the proposed method were studied and determined under optimized conditions according to international guidelines. HPLC analysis of FIN and CIT molecules was performed by isocratic elution of a mixture of 50 % Acetonitrile, 40 % pH:3 phosphate buffer and 10 % methanol with flow rate 1.0 mL min−1. The chosen wavelengths in PDA was determined as 238 nm for FIN and 213 nm for CIT. The limits of detection (LOD) for proposed method were 6.32 ng mL−1 for FIN and 6.85 ng mL−1 for CIT molecules. RSD % values were lower than 5.5 % in analysis of model solutions including 250 and 500 ng mL−1 of target molecules. Recovery values by means of synthetic urine and saliva samples were in the range of 95.7–105.4 % for both molecules. [ABSTRACT FROM AUTHOR]

The presence of anti-SARS-CoV-2 antibodies in serum indicates protection against the virus; however, although circulating antibodies control infection within the body, secretory IgA could provide better protection by acting as a primary barrier in containing the infection and therefore dispersing the virus. Our objective was to evaluate the seroconversion and titers of IgG, IgA and IgM against SARS-CoV-2 in Personnel Occupationally Exposed to SARS-CoV-2 (POE) in the Manuel Gea Gonzalez General Hospital. Using the ELISA technique, the antibody titers (IgG, IgA and IgM) against the synthetic peptides Spike (RBD, Arg319-Phe541) and Nucleocapsid (NCP, Met1-Ala419) were determined in the serum of three study groups: A) infected and vaccinated POE, b) uninfected and vaccinated POE and C) uninfected and unvaccinated POE. In addition, IgA was also detected in the saliva of group C. The percentage and titers of IgM, IgA and IgG versus NCP and RBD were similar in groups A and B (above 35 %), but not in group C, in the that IgG and IgA showed values below 10 % and no seroconversion of IgM versus RBD was observed. Regarding the detection of IgA in saliva, 35 % positivity was observed with RBD antigen and 25 % with NCP, higher percentages than in serum. Although RT-qPCR did not detect SARS-CoV-2 infection in Group C, antibodies against SARS-CoV-2 were detected; this could indicate that secretory IgA was excellent protection. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic introduced an urgent need for rapid and high-throughput testing for SARS-CoV-2. RNA extraction is a major bottleneck for RT-qPCR. We describe a semi-automated, extraction-free RT-qPCR assay for detection of SARS-CoV-2 in nasal swab and saliva samples on a single platform. With a limit of detection of 4 copies/mL, this laboratory developed test performed equivalently to established methods requiring nucleic acid extraction. Five technologists staffing two shifts per day (80 person-hours) processed more than 400,000 samples over 10 months. Patients opted to provide nasal swab samples (83.6%) more frequently than saliva (16.4%), creating the added challenge of producing swab collection kits. Real-world testing data indicated a higher frequency of SARS-CoV-2 detection in saliva (10.1%) compared to nasal swab (7.7%). This cost-effective and quickly scalable approach is suitable for pandemic preparedness planning related to surveillance and diagnostic testing.

Highlights • Screening and confirmatory analysis is proposed for polar endogenous compounds. • No need for instrumental modification to switch from screening to confirmatory steps. • C18 column is used in both analyses by modifying mobile phase composition. • Applicability of the method is checked with creatinine, polyamines and amino acids. Abstract In this paper, a high-throughput approach is proposed for the sensitive screening and the confirmatory analysis of polar compounds in saliva using a two-step approach based on a liquid chromatographic system coupled to a triple quadrupole mass spectrometer. A reversed-phase chromatographic column was used in both steps and changes in the composition of the mobile phase allowed the screening and the confirmatory analyses to be performed with the same instrumental configuration. The proposed strategy has been tested for the determination of a multiclass group of polar endogenous compounds (creatinine, polyamines and amino acids) in saliva samples. The validation of the entire procedure showed consistent results for all the compounds in both steps. Repeatability and reproducibility were evaluated for both procedures, with values below 8% in the case of repeatability and 17% in the case of reproducibility. The instrumental limits of detection were found to be between 1.22 × 10−3 and 46.1 × 10−3 mg/L for creatinine and lysine, respectively, and accuracy of the method was evaluated in terms of apparent recoveries and values were found to be between 80 and 127%. Matrix effects were evaluated and it was found that the analytical outcome was influenced by the matrix of the sample. Thus, a one-point standard addition method was used for quantification. The optimized two-step procedure was applied to saliva samples from apparent healthy volunteers. Overall, satisfactory results were obtained in both steps, demonstrating its applicability for quantitative analysis of polar endogenous compounds in this kind of matrices. [ABSTRACT FROM AUTHOR]

Abstract We present the development and validation of a sensitive method for the reliable determination of sixteen polycyclic aromatic hydrocarbons (PAHs) in saliva samples, which can be used as exposure markers. This method was based on a liquid-liquid extraction and programmed temperature vaporizer-gas chromatography-mass spectrometry analysis (LLE-PTV-GC-MS). Since no matrix effect was found, quantification was performed using external calibration. The detection limits were lower than or equal to 0.057 µg L−1 for all analytes, and repeatability and reproducibility (expressed as relative standard deviation, RSD) were always lower than or equal to 11% and 19%, respectively. The method was used to quantify polycyclic aromatic hydrocarbons in the saliva samples taken from firefighters and unexposed volunteers, detecting the presence of seven of the sixteen analytes analysed. Two of the compounds (fluorene and phenanthrene) were found in the both exposed and unexposed individuals, while the remaining five analytes (naphthalene, acenaphthylene, anthracene, fluoranthene and pyrene) were only detected in samples taken from the firefighters. Good discrimination between the firefighters and the unexposed volunteers was obtained through a principal component analysis. Graphical abstract fx1 Highlights • A method for the determination of 16 polycyclic aromatic hydrocarbons is proposed. • The method is rapid, simple and sensitive. • Fifty-five saliva samples from firefighters and unexposed volunteers were analysed. • Differences between the groups of samples considered were found. • External calibration was employed to quantify these compounds in saliva samples. [ABSTRACT FROM AUTHOR]

Predation on livestock is a cause of serious and long-lasting conflict between farmers and wildlife, promoting negative public attitudes and endangering conservation of large carnivores. However, while large carnivores, especially the grey wolf (Canis lupus), are often blamed for killing sheep and other farm animals, free-ranging dogs may also act as predators. To develop appropriate measures for livestock protection, reliable methods for identifying predator species are critical. Identification of predators from visual examination of livestock wounds can be ambiguous and genetic analysis is strongly preferable for accurate species determination. To estimate the proportion of wolves and dogs implicated in sheep predation, we developed a sensitive genetic assay to distinguish between wolves and domestic dogs. A total of 183 predator saliva samples collected from killed sheep in Estonia were analysed. The assay identified the predator species in 143 cases (78%). Sheep were most often killed by wolves (81%); however, predation by dogs was substantial (15%). We compared the molecular results with field observations conducted by local environmental officials and recorded some disagreement, with the latter underestimating the role of dogs. As predator saliva samples collected from prey are often of poor quality, we suggest using mitochondrial DNA as a primary tool to maximise the number of successfully analysed samples. We also suggest adopting forensic DNA analysis more widely in livestock predation assessments as a legislative measure since misidentification that is biased against wolves can be counterproductive for conservation by enhancing conflict with society and leading to increased culling and poaching. [ABSTRACT FROM AUTHOR]

Purpose: Human papillomavirus (HPV) is known to play a role in the development of head and neck squamous cell carcinomas (HNSCC) and to date, no study has reported on the association between oral HPV infection and HNSCC in the Caribbean. The objective was to determine the prevalence of oral HPV infection in the French West Indies (FWI), overall and by HPV genotype, among HNSCC cases and healthy population controls.Method: We used data from a population-based case-control study conducted in the FWI. The prevalence of oral HPV was estimated separately among 100 HNSCC cases (mean age 59 years) and 308 population controls (mean age 57 years). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using a logistic regression adjusting for age, sex, tobacco, and alcohol consumption, to assess the association between oral HPV infection and HNSCC.Results: Prevalence of oral HPV infections was 26% in controls (30% in men and 14% in women) and 36% in HNSCC cases (36% in men, 33% in women). HPV52 was the most commonly detected genotype, in cases and in controls. The prevalence of HPV16, HPV33, and HPV51 was significantly higher in cases than in controls (p = 0.0340, p = 0.0472, and 0.0144, respectively). Oral infection with high-risk HPV was associated with an increase in risk of HNSCC (OR 1.99, 95% CI 0.95-4.15). HPV16 was only associated with oropharyngeal cancer (OR 16.01, 95% CI 1.67-153.64).Conclusion: This study revealed a high prevalence of oral HPV infection in this middle-aged Afro-Caribbean population, and a specific distribution of HPV genotypes. These findings may provide insight into HNSCC etiology specific to the FWI. [ABSTRACT FROM AUTHOR]

The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) pandemic demanded rapid diagnosis to isolate new COVID-19 cases and prevent disease transmission. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) rapidly became the gold standard for diagnosis. However, due to the high cost and delay of the results, other types of diagnosis were implemented, such as COVID-19 Ag Rapid Tests and Reverse Transcription Technique followed by Loop-Mediated isothermal Amplification (RT-LAMP). In this work, we validated the use of RT-LAMP in saliva samples rather than nasopharyngeal swabs, as the collection is more comfortable. First, we selected 5 primer sets based on the limit of detection for SARS-CoV-2 RNA, then validated their sensitivity and specificity in patient samples. A total of 117 samples were analyzed by fluorometric RT-LAMP and compared with qRT-PCR results. Our results show that the use of a high-sensitive primer ORF1-a, together with a low-sensitive primer set Gene E (time to threshold of 22.9 and 36.4 minutes, respectively, using 200 copies of viral RNA), achieved sensitivity in purified RNA from saliva samples of 95.2% (95% CI 76.1‒99.8) with 90.5% specificity (95% CI 69.6‒98.8) (n = 42).As RNA purification increases the turnaround time, we tested the outcome of RT-LAMP utilizing raw saliva samples without purification. The test achieved a sensitivity of 81.8% (95% CI 59.7‒94.8) and a specificity of 90.9% (95% CI 70.8‒98.8). As a result, the accuracy of 92.9% (95% CI 80.5‒98.5) in purified RNA-saliva samples was lowered to an acceptable level of 86.4% (95% CI 72.6‒94.8) in raw saliva. Although mass vaccination has been implemented, new strains and low vaccination progress helped to spread COVID-19. This study shows that it is feasible to track new COVID-19 cases in a large population with the use of raw saliva as sample in RT-LAMP assay which yields accurate results and offers a less invasive test., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (Copyright © 2023 Sociedade Brasileira de Infectologia. Published by Elsevier España, S.L.U. All rights reserved.)

Lactate monitoring is an important issue in the food industry, in clinical diagnosis and sport medicine. Biosensors that can quantify lactic acid in biological samples are extremely attractive because of their advantages such as simplicity, ease of miniaturization, high sensitivity and low-cost. The proposed biosensor is based on a screen-printed electrode modified with Prussian Blue, that senses the hydrogen peroxide produced by the reaction catalysed by the lactate oxidase enzyme immobilized onto the electrode surface, coupled with a portable instrumentation. This biosensor showed a working range of 0.025–0.25 mM with a detection limit of 0.01 mM. After recovery studies, the biosensor was employed for the analysis of 12 saliva samples, taken from athletes, whose lactate levels were compared with the blood lactate content measured with a portable lactate analyser. The results showed a good correlation. The developed electrochemical biosensor could be a useful, alternative and non-invasive tool for a correct and rapid monitoring of lactate in saliva. This method is easy to use, cost effective, rapid, and suitable for analysis performed outside the classical diagnostic laboratory. [ABSTRACT FROM AUTHOR]

Polyvalent mechanical bacterial lysate is effective in the prevention of respiratory tract infections, although its mechanism of action is not entirely elucidated. Because epithelial cells constitute the frontline defense against infections, we investigated the molecular mechanisms of innate response exerted by bronchial epithelial cells in the presence of polyvalent mechanical bacterial lysate. By using primary human bronchial epithelial cells, we observed that polyvalent mechanical bacterial lysate was able to increase the expression of cellular adhesion molecules such as ICAM-1 and E-cadherin, as well as the expression of amphiregulin, a growth factor able to support human bronchial epithelial cell proliferation. Remarkably, polyvalent mechanical bacterial lysate promoted in human bronchial epithelial cells the de novo expression of human β-defensin-2, a major antimicrobial peptide, conferring them a direct antimicrobial activity. Moreover, polyvalent mechanical bacterial lysate-stimulated human bronchial epithelial cells provided signals for increased IL-22 production by innate lymphoid cells via IL-23, which could further contribute to the release of antimicrobial peptides by epithelial cells. In agreement with these in vitro data, the concentration of both IL-23 and antimicrobial peptides (human β-defensin-2 and LL-37) increased in the saliva of healthy volunteers after sublingual administration of polyvalent mechanical bacterial lysate. Altogether, these results indicate that polyvalent mechanical bacterial lysate administration might support mucosal barrier integrity and promote mechanisms of antimicrobial activity in airway epithelial cells., (© The Author(s) 2023. Published by Oxford University Press on behalf of Society for Leukocyte Biology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

PROBLEM To add to diversity in our state biobank, we explored the feasibility of collecting genetic material from adolescents with oppositional defiant disorder (ODD) and/or conduct disorder (CD) and their family members. We also preliminarily explored genetic factors associated with ODD and/or CD by comparing participant data to 1000 Genome Project data on minor allele frequencies. METHODS Adolescents with ODD and/or CD and family members provided saliva samples for genetic testing. We evaluated five single-nucleotide polymorphisms (SNPs), respectively, in the dopamine receptor subtype D2, dopamine receptor subtype D3, dopamine beta-hydroxylase, dopamine transporter gene SLC6A3, and alpha-2-adrenergic receptor genes. Fisher's exact tests were used to examine differences in minor allele frequencies for each SNP. FINDINGS Thirty-one viable samples were genotyped from 15 affected adolescents and 16 unaffected family members; the 60% consent rate reflected high feasibility. Compared with the 1000 Genome Project frequencies, affected adolescents had higher frequencies of the genetic variant in the dopamine receptor subtype D2 ( p = .05) and dopamine beta-hydroxylase ( p = 0.03), but not of the other three SNPs examined. CONCLUSIONS Collecting genetic materials from an ethnically diverse sample of affected adolescents and their families is feasible. We offer practical suggestions to strengthen the integrity of future research studies. [ABSTRACT FROM AUTHOR]

The advances in the analytical methodology of the clinical laboratories in the last decades and the development of numerous dispositives and techniques in the obtention and processing of saliva samples with adequate characteristics and quantities for analysis has made possible a totally new field in the laboratory diagnosis based in the use of this sample. The principal advantages of the use of saliva samples in laboratory diagnosis instead of blood samples are: low risk of adquisition of accidental infections associated with venipuncture in health personnel, the easy obtention of this sample mainly in small or premature children, obese or in chemotherapy patients and the fact that its obtention is not an invasive or painful procedure, does not requires specific training, it can be repeated in numerous occasions and his applications are diverse; hormones, abuse of drugs, heavy metals, diagnosis and management of infectious diseases, metabolic, neoplastic, congenital metabolic disorders, forensic, legal and labor medicine, and for epidemiological purpouses. The main disadvantages of saliva samples in comparation with blood samples, are that the analytes are in lower concentrations, the possible interference with some tests derived from the bacterial enzymatic activity, food and mucous presence in saliva samples, however this problems has been surpassed using filtering and using more quantities of sample. In this work we described the characteristics, components, functions and the origen of human saliva, its applications in the laboratory diagnosis, the adequate obtention of samples, and the advantages and disadvantages of this sample in relation with blood. [ABSTRACT FROM AUTHOR]

The article discusses a randomized controlled trial investigating how the circadian rhythm of salivary testosterone is altered by resistance exercise in young male recreational lifters with two years of experience in weightlifting. Topics include the study's experimental design, the anabolic impact of testosterone secretion rates in relation to circadian rhythm variations, and the effect of resistance exercise on circadian secretion of salivary testosterone throughout 16 waking hours.

A novel, rapid, and facile method for the colorimetric determination of calcium using micro-analytical paper-based devices (μ-PADs) was developed. The proposed analytical method utilizes the color differences developing, after the addition of calcium, on the surface of the devices because of the complexation reaction of calcium with Methylthymol Blue (MTB) at room temperature, in alkaline pH. The devices were manufactured with chromatographic paper, using wax barriers, and the analytical protocol was easily implemented without the need of any experimental apparatus except for a simple imaging device. The user must regulate the pH, add the solutions on the paper, and measure the color intensity of the formed Ca(II)-MTB complex with a flatbed scanner. The experimental conditions for optimum color development, the possible interfering substances, and the reliability of the paper devices in different preserving conditions were optimized, with satisfactory results. The method exhibited acceptable detection limits (2.9 mg L -1 ) with sufficiently good precision, which varied from 4.2% (intra-day) to 6.4% (inter-day). Saliva samples from healthy volunteers were successfully analyzed, and the calcium levels were calculated in the range of 30.71 to 84.15 mg L -1 .

ABSTRACT A vortex-assisted liquid-liquid micro-extraction coupled with high-performance liquid chromatography, with UV-vis, is proposed to pre-concentrate methyl methacrylate and to improve separation in biological matrices. The use of 1-octanol as extracting phase, its volume, the need for a dispersant agent, the agitation conditions and the cooling time before phase separation were evaluated. In optimum conditions, enrichment factors of 20 (±0.5) and enrichment recovery of 99% were obtained. The straightforward association of this extraction process with the HPLC method, previously regulated by the International Organization for Standardization, afforded a detection limit of 122 ng/mL and a quantification limit of 370 ng/mL. The within-batch precision, relative standard deviation, was 3% for a sample with 1.49 µg/mL and 4% for a sample with 13.4 µg/mL. The results showed a between batch-precision of 21% for experiments performed on five different days, for a sample with a concentration of 1.10 µg/mL in methyl methacrylate. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C8-cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS-LC-MS/MS is reported. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objective To evaluate salivary progesterone as a predictor of early preterm birth ( PTB) and compare it with transvaginal sonographic ( TVS) cervical length in asymptomatic high-risk women. Design Prospective study. Setting Departments of Obstetrics and Gynaecology and Biochemistry at UCMS & GTBH, Delhi, India. Sample Ninety pregnant women. Methods The progesterone concentration in saliva of asymptomatic pregnant women at high risk for preterm delivery was estimated by immunoassay, and cervical length was measured by TVS, at the first antenatal visit at 24-28 weeks of gestation, and then repeated 3-4 weeks later. Main outcome measures Early PTB, mean and critical cut-off values of salivary progesterone, and a diagnostic value comparison of salivary progesterone with TVS cervical length. Results The mean value of salivary progesterone was significantly lower in all women who delivered at <37 weeks of gestation ( n = 38), compared with the term group ( n = 52; P < 0.001). Salivary progesterone decreased significantly from the first to the second visit, with the maximum decrease observed in women who delivered at <34 weeks of gestation (29.6%, 95% CI 17.8-41.4%, P < 0.002). The single predictive critical cut-off value for salivary progesterone was 2575 pg/ml, below which more than 80% of women delivered prematurely before 34 weeks of gestation, with sensitivity, specificity, and positive and negative predictive values of 83% (95% CI 58.6-96.4%), 86% (95% CI 75.9-93.1%), 60% (95% CI 38.6-78.8%) and 95% (95% CI 87.1-99.0%), respectively. The TVS cervical length decreased significantly ( P < 0.001) in the women who delivered prematurely. Conclusions Low salivary progesterone concentration can be used for predicting early PTB in asymptomatic high-risk women. [ABSTRACT FROM AUTHOR]

COVID-19 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus affecting the world population. Early detection has become one of the most successful strategies to alleviate the epidemic and pandemic of this contagious coronavirus. Surveillance testing programs have been initiated in many countries worldwide to prevent the outbreak of COVID-19. In this study, we demonstrated that our previously established clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a-based assay could detect variants of concern during 2021 in Thailand, including Alpha, Beta, and Delta strains as well as Omicron strain in early 2022. In combination with the newly designed saliva collection funnel, we established a safe, simple, economical, and efficient self-collection protocol for the COVID-19 screening process. We successfully utilized the assay in an active case finding with a total number of 578 asymptomatic participants to detect the SARS-CoV-2 in saliva samples. We finally demonstrated that the validation and evaluation in a large-scale setting could provide valuable information and elaborate the practicality of the test in real-world settings. Our optimized protocol yielded effective results with high sensitivity, specificity, and diagnostic accuracy (96.86%). In addition, this study demonstrates COVID-19 active case findings in low-resource settings, which would be feasible and attractive for surveillance and outbreak prevention in the future.

Abstract: A kinetic spectrophotometric method for the determination of thiocyanate, based on its inhibitory effect on silver(I) catalyzed substitution of cyanide ion, by phenylhydrazine in hexacyanoferrate(II) is described. Thiocyanate ions form strong complexes with silver(I) catalyst which is used as the basis for its determination at trace level. The progress of reaction was monitored, spectrophotometrically, at 488nm (λ max of [Fe(CN)5PhNHNH2]3−, complex) under the optimum reaction conditions at: 2.5×10−3 M [Fe(CN)6]4−, 1.0×10−3 M [PhNHNH2], 8.0×10−7 M [Ag+], pH 2.8±0.02, ionic strength (μ) 0.02M (KNO3) and temperature 30±0.1°C. A linear relationship obtained between absorbance (measured at 488nm at different times) and inhibitor concentration, under specified conditions, has been used for the determination of [thiocyanate] in the range of 0.8–8.0×10−8 M with a detection limit of 2×10−9 M. The standard deviation and percentage error have been calculated and reported with each datum. A most plausible mechanistic scheme has been proposed for the reaction. The values of equilibrium constants for complex formation between catalyst–inhibitor (K CI), catalyst–substrate (K s) and Michaelis–Menten constant (K m) have been computed from the kinetic data. The influence of possible interference by major cations and anions on the determination of thiocyanate and their limits has been investigated. [Copyright &y& Elsevier]

Eur J Clin Invest 2010; 40 (2): 183–186 Background Given the high correlation between the serum and saliva hormone values demonstrated at rest, saliva provides a convenient non-invasive way to determine dehydroepiandrosterone (DHEA) and cortisol concentrations. However, to our knowledge, pituitary adrenal recovery following short-term suppression with corticosteroids has never been investigated in saliva. The aim of this study was therefore to examine how steroid hormone concentrations in saliva are influenced by short-term corticosteroid administration. Materials and methods We studied saliva DHEA and cortisol concentrations before, during (day 1–day 7) and following (day 8–day 16) the administration of oral therapeutic doses of prednisone (50 mg daily for 1 week) in 11 healthy recreationally trained women. Results Mean saliva DHEA and cortisol concentrations decreased immediately after the start of prednisone treatment ( P < 0·05). Three days after concluding prednisone administration, both saliva DHEA and cortisol had returned to pretreatment levels. Conclusions These data are consistent with previous studies on blood samples and suggest that non-invasive saliva samples may offer a practical approach to assessing pituitary-adrenal function continuously during and after short-term corticosteroid therapy. [ABSTRACT FROM AUTHOR]

Aims: To develop a PCR-denaturing gradient gel electrophoresis (PCR-DGGE) method for the detection and identification of Campylobacter, Helicobacter and Arcobacter species (Epsilobacteria) in clinical samples and evaluate its efficacy on saliva samples from humans and domestic pets. Methods and Results: A semi-nested PCR was developed to allow sensitive detection of all Epsilobacteria, with species separation undertaken by DGGE. A database was constructed in BioNumerics using 145 strains covering 51 Campylobacter, Arcobacter and Helicobacter taxa; Nineteen distinct DGGE profile-groups were distinguished. This approach detected Epsilobacteria in all saliva samples collected from humans, cats and dogs, and identified Campylobacter concisus and/or Campylobacter gracilis in the human samples. The pet animal samples were taken from individuals with oral/dental diseases; PCR-DGGE identified up to four different species in each sample. The most common species detected included Wolinella succinogenes, Arcobacter butzleri and two hitherto uncultured campylobacters. The enteropathogen Campylobacter lari was also found. Conclusions: PCR combined with DGGE is a useful tool for direct detection and preliminary identification of Epsilobacteria in the oral cavity of humans and small animals. Significance and Impact of the Study: The PCR-DGGE method should allow determination of the true prevalence and diversity of Epsilobacteria in clinical and other samples. Contact with the oral cavity of domestic pets may represent a route of transmission for epsilobacterial enteric diseases. [ABSTRACT FROM AUTHOR]

Abstract: An automated method is described for the determination of zinc in human saliva by electrothermal atomic absorption spectrometry (ET AAS) after on-line dilution of samples with a significant reduction of sample consumption per analysis (<0.4mL including the dead volume of the system). In order to fulfill this aim without changing the sample transport conduits during the experiments, a flow injection (FI) dilution system was constructed. Its principal parts are: one propulsion device (peristaltic pump, PP) for either samples, standards or washing solution all located in an autosampler tray and for the surfactant solution (Triton X-100) used as diluent, and a two-position time based solenoid injector (TBSI1) which allowed the introduction of 10μL of either solution in the diluent stream. To avoid unnecessary waste of samples, the TBSI1 also permitted the recirculation of the solutions to their respective autosampler cups. The downstream diluted solution fills a home made sampling arm assembly. The sequential deposition of 20μL aliquots of samples or standards on the graphite tube platform was carried out by air displacement with a similar time based solenoid injector (TBSI2). The dilution procedure and the injection of solutions into the atomizer are computer controlled and synchronized with the operation of the temperature program. Samples or standards solutions were submitted to two drying steps (at 90 and 130°C), followed by pyrolysis and atomization at 700 and 1700°C, respectively. The aqueous calibration was linear up to 120.0μgL−1 for diluted standard solutions/samples and its slope was similar (p >0.05) to the standard addition curve, indicating lack of matrix effect. The precision tested by repeated analysis of real saliva samples was less than 3% and the detection limit (3σ) was of 0.35μgL−1. To test the accuracy of the proposed procedure, recovery tests were performed, obtaining mean recovery of added zinc of 97.8±1.3%. Furthermore, Zn values estimated by the procedure developed in this work were compared with those obtained by a standard addition flame-AAS method applied to 20 randomly selected saliva samples. No significant differences (p >0.05) were obtained between the two methods. Zinc levels in saliva samples from 44 healthy volunteers, 15 male and 29 female, with ages between 20 and 51 years (mean 30.50±9.14 years) were in the range 22–98μgL−1 (mean of 55±17μgL−1), similar to some and different from others reported in the literature. It was found that zinc values for male were statistically higher (p =0.006) than for female. [Copyright &y& Elsevier]

An analytical method was developed to determine the undecapetide substance P (SP) based on capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. SP was derivatized with the fluorogenic reagent 2,3-naphthalenedicarboxaldehyde (NDA) prior to injection into the CE-LIF system. The pre-column derivatization scheme combined with injection enhancement techniques extends the detectability of SP to the subnanomolar level. Limit of detection (LOD) of 100 pM was achieved without pre-concentrating the sample prior to injection. The reproducibility for six different preparations of a standard sample containing 5 nM of SP was 6.8% RSD and that of the CE migration time was 0.08% RSD. The method was used to determine SP in a saliva sample. [Copyright &y& Elsevier]

• A modified magnetic solvent assisted dispersive solid-phase extraction is presented • It is applied for trace determination of cortisol and cortisone in human saliva • LC-MS/MS is used to measure both analytes in the M-SA-DSPE extracts • Small amounts of disperser solvent and magnetic sorbent are required • Fast determination is achieved with no additional equipment A modification of magnetic-based solvent-assisted dispersive solid-phase extraction (M-SA-DSPE) has been employed for the determination of the biomarkers cortisol and cortisone in saliva samples. M-SA-DSPE is based on the dispersion of the sorbent material by using a disperser solvent like in dispersive solid phase extraction (SA-DSPE) but a magnetic sorbent is used like in magnetic dispersive solid-phase extraction (M-DSPE). Thus, the magnetic sorbent containing the target analytes is retrieved using an external magnet like in M-DSPE. Finally, the analytes are desorbed into a small volume of organic solvent for the subsequent chromatographic analysis. To this regard, a M-SA-DSPE-based method was developed using a magnetic composite as sorbent, made of CoFe 2 O 4 magnetic nanoparticles embedded into a reversed phase polymer (Strata-XTM-RP), which exhibits affinity to the target analytes. Then, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to measure both analytes in the M-SA-DSPE extract. Under the optimized conditions, good analytical features were obtained: limits of detection of 0.029 ng mL−1 for cortisol and 0.018 ng mL−1 for cortisone, repeatability (as RSD) ≤ 10 %, and relative recoveries between 86 and 111 %, showing no significant matrix effects. Finally, the proposed method was applied to the analysis of saliva from different volunteers. This new methodology allows a fast and non-invasive determination of cortisol and cortisone, and it employs small amounts of sample, organic solvent and sorbent. Likewise, the sample treatment is minimum, since any supporting equipment (vortex, centrifuge, ultrasounds, etc.) is required. [ABSTRACT FROM AUTHOR]

• Determination of polyamines and N -acetylated forms via in-situ derivatization. • Derivatization, liquid-liquid extraction and analysis using PTV-GC–MS is proposed. • Internal standard calibration used for quantification. • Limits of quantification within the low µg L −1 range are achieved. A simple method for the determination of polyamines and their N -acetylated forms was developed using benzoyl chloride as derivatization reagent, and 1,6-diaminohexane as internal standard, followed by liquid-liquid extraction with ethyl acetate. The organic extract was injected in a gas chromatograph using a programmed temperature vaporizer and the determination and quantification was performed with a quadrupole mass spectrometer. There was no matrix effect with the proposed method, so internal calibration was used to quantify the corresponding derivatives. Good linear responses were obtained in the range from the limits of detection to 500 µg L −1 (50 µg L −1 for spermidine), with correlation coefficients varying from 0.9591 to 0.9968. The limits of quantification (S/ N = 10) ranged 1.0 – 8.3 µg L −1. Recoveries were found between 82 – 117%, showing the good accuracy of the proposed method. Intra- and inter-day precision assays, expressed as relative standard deviation (RSD) were evaluated at two different concentration levels (low and high), showing values in the range of 2.4 – 6.1% and 5.2 – 9.0% for repeatability and reproducibility, respectively (6.9 – 9.7% and 14.1 – 14.6% for spermidine). Successful determination of the studied polyamines and their N -acetylated forms was performed on the saliva of 17 volunteers. [ABSTRACT FROM AUTHOR]