Correlates of substance use in a large naturalistic cohort of young people with early and emerging psychosis.

BACKGROUND: Substance use remains a barrier to recovery for young people accessing early intervention services for psychosis. While correlates of use have been explored in populations experiencing a first episode of psychosis (FEP), sample sizes have been small and less research assesses cohorts at ultrahigh risk of psychosis (UHR). METHODS: This study uses data from a naturalistic cohort including UHR and FEP participants (N = 1252) to elucidate clinical correlates of use in the past 3 months of any illicit substance, amphetamine-type stimulants (ATS), cannabis, and tobacco. Moreover, network analysis based on use of these substances and additionally alcohol, cocaine, hallucinogens, sedatives, inhalants, and opioids was completed. RESULTS: Young people with FEP used substances at significantly higher rates than those at UHR. High concurrence of use was seen between substances. In the FEP group, participants who had used any illicit substance, ATS, and/or tobacco had increased positive symptoms and decreased negative symptoms. Young people with FEP who used cannabis had increased positive symptoms. In the UHR group, participants who had used any illicit substance, ATS, and/or cannabis in the past 3 months showed decreased negative symptoms compared to those who had not. CONCLUSION: A distinct clinical picture of more florid positive symptoms and alleviated negative symptoms seen in those who use substances in the FEP group appears muted in the UHR cohort. Treating young people at UHR in early intervention services represents the earliest opportunity to address substance use early to improve outcomes.

Heterogeneity of quality of life in the later stages of first-episode psychosis recovery.

PURPOSE: First-episode psychosis (FEP) is characterised by wide heterogeneity in terms of symptom presentation and illness course. However, the heterogeneity of quality of life (QoL) in FEP is not well understood. We investigated whether subgroups can be identified using participants' responses on four QoL domains (physical health, psychological, social relationships, and environmental) 18-months into the recovery phase of FEP. We then examined the discriminant validity of these subgroups with respect to clinical, cognitive, and functioning features of FEP. METHOD: Demographic and clinical characteristics, QoL, cognition, and functioning were assessed in 100 people with FEP at the 18-month follow-up of a randomised controlled trial of Individual Placement Support, which aims to facilitate vocational recovery. QoL was measured using the World Health Organisation's QoL-BRIEF. A two-stage clustering approach using Ward's method and Squared Euclidean Distance with a k-means confirmation was conducted. Multinomial logistic regressions were used to establish external validity. RESULTS: Three QoL subgroups emerged: a 'good' subgroup with relatively high QoL across all domains (31%), an 'intermediate' subgroup with relatively low psychological QoL (48%) and a 'poor' subgroup with markedly low social relationship QoL (21%). Negative symptoms, depressive symptoms, social/occupational functioning, and social inclusion at follow-up predicted subgroup membership. Sensitivity analysis found similar results. CONCLUSION: Although some individuals with FEP have QoL comparable to individuals without mental ill health, QoL can remain concerningly low despite treatment efforts. Future research on interventions that target factors associated with poor QoL, such as low social inclusion, is required to counteract prolonged poor QoL in FEP.

Social inclusion, intersectionality, and profiles of vulnerable groups of young people seeking mental health support.

BACKGROUND: headspace centres provide enhanced primary mental healthcare for young people. A priority is to provide services for all young people irrespective of a range of social disadvantages or social exclusion. The aims of this study were to: (i) delineate extent of social inclusion across domains of housing, studying/employment, functioning, alcohol, and other drug use; and (ii) map profiles of young people deemed vulnerable to experiencing additional barriers to accessing services based on their social inclusion domains (e.g., those living in unstable housing, not in employment/education, and/or experiencing intersecting or multiple forms of disadvantage or difficulties), including detailing their clinical characteristics. METHODS: Young people were recruited from five headspace centres. Data relevant to social inclusion were examined. Multivariate logistic regression models were used to determine overlap between vulnerable groups, functional, social, clinical, and behavioural factors. RESULTS: 1107 young people participated, aged 12-25 years (M = 18.1 years, SD = 3.3), most living in stable housing (96.5%) and engaged in studying/employment (84.8%). Specific vulnerabilities were evident in young people with NEET status (15.2%); in unstable accommodation (3.5%); of culturally diverse backgrounds (CALD) (12.2%); living in regional areas (36.1%); and identifying as lesbian, gay, bisexual, transgender, intersex, queer/questioning, and asexual plus (LGBTIQA+; 28.2%). Higher levels of distress, substance use, functional impairment, and lower social support were reported by those who were NEET and/or in unstable housing. LGBTIQA+ status was associated with high distress, depressive symptoms, and suicidal ideation. CONCLUSIONS: Most participants reported good social support, stable housing, and engagement in work or education. Those deemed vulnerable were likely to experience social exclusion across multiple domains and reported more mental health problems. The co-occurrence of mental ill-health and social exclusion highlights the importance of integrated mental healthcare.

Clinical and functional characteristics of a subsample of young people presenting for primary mental healthcare at headspace services across Australia.

PURPOSE: Headspace services provide treatment options to young people seeking mental healthcare. To obtain a better understanding of needs and characteristics of this population, and effectively evaluate services, we require novel youth-specific outcome measures. As part of our broad research program to establish such measures, a sample of young people were recruited and assessed. The study describes (i) methodology used to obtain clinical, functioning, and substance use characteristics of young people presenting to headspace services; and (ii) an overview of these characteristics. METHODS: Young people presenting to headspace centres were recruited. Multidimensional information was obtained relating to clinical and functional outcomes, demographic information, and lifestyle factors. RESULTS: 1107 young help-seeking individuals were recruited. Participants were most likely young adults aged M = 18.1 years, SD = 3.3, with diagnoses of depression and/or anxiety (76.6%, n = 801), engaged in work and study (84.9%, n = 890), and living with parent(s) (68.9%, n = 736). Impairments in functioning were moderate as indicated by the Social and Occupational Functioning Assessment Scale (M = 65.2, SD = 9.5), substance use was common (alcohol 62.7%, n = 665; illicit substances 30.5%, n = 324), and current suicidal ideation was reported by a third (33.6%, n = 358). CONCLUSIONS: A broad dataset was obtained providing an insight into key clinical, functional and quality of life characteristics of these individuals. We observed that young people present with complex problems, comorbid diagnoses, moderate levels of symptomatology, impairments in functioning, substance use, and suicidal ideation. This work provides the foundation for our broader research program aiming to develop novel, relevant and youth-specific, change and outcome measures.

[Comparison of epidermal growth factor receptor (EGFR) gene T790M mutation by droplet digital PCR and Super-ARMS PCR in plasma ctDNA samples of non-small cell lung cancer patients with the resistance to EGFR-tyrosine kinase inhibitor].

Objective: To compare droplet digital PCR (ddPCR) and Super-amplification refractory mutation system (ARMS) in the detection of T790M mutation of epidermal growth factor receptor (EGFR) in the plasma of non-small cell lung cancer patients who had developed resistance to EGFR tyrosine kinase inhibitor (TKI) , and to investigate the clinical application of ddPCR. Methods: Plasma samples were collected from non-small cell lung cancer patients who had acquired EGFR-TKI resistance at Shanghai Pulmonary Hospital, Tongji University, from May 2017 to November 2017. Extracted ctDNA was analyzed by ddPCR and Super-ARMS to evaluate the T790M mutation status of EGFR gene. Results: A total of 37 patients with activating EGFR mutation that acquired resistance to EGFR-TKI were selected in the study, including 17 male and 20 female with a median age of 64 years (range 40-83 years). Before TKI treatment, all the patients harbored EGFR inhibitor sensitive mutations but without T790M mutation. After acquiring resistance to EGFR-TKI treatment, the T790M mutation rate detectable by ddPCR was 45.9% (17/37). In contrast, the mutation rate of T790M detectable by Super-ARMS was 35.1% (13/37, P<0.05). For the 13 positive cases detected by Super-ARMS (ΔCt<8), they were all positive by ddPCR assay; Among the 10 negative cases detected by Super-ARMS (ΔCt≥8), there were 3 cases positive by ddPCR assay. For patients without ΔCt by Super-ARMS assay, there was one weak positive case detectable by ddPCR assay. Among 17 EGFR T790M positive patients, 9 received EGFR inhibitor Osimertinib treatment, and 7 of them had good therapeutic response after the treatment. Conclusions: While a significant correlation between the two methods is shown. ddPCR is more sensitive than Super-ARMS in the detection of EGFR T790M mutation, indicating that it is a better method in guiding target drug therapy of non-small cell lung cancer patients after acquiring the resistance to EGFR-TKI.

High thyroid-stimulating hormone level is associated with the risk of developing atherosclerosis in subclinical hypothyroidism.

The aim of our study was to assess the potential role of thyroid-stimulating hormone (TSH) in the risk of developing atherosclerosis in subclinical hypothyroidism (SCH). A cohort of 240 SCH patients and 150 euthyroid volunteers were recruited for the study. SCH patients were stratified into 2 groups according to TSH levels (group A: TSH<10 mIU/l; group B: TSH>10 mIU/l). All subjects were examined for clinical and biochemical parameters. Visfatin, omentin-1, and circulating endothelial biomarkers were measured. Patients in group B received l-thyroxine replacement to achieve euthyroidism; after 6 months of euthyroidism all measurements were repeated. Patients with SCH had higher total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and C-reactive protein (CRP) levels and lower nitric oxide (NO) and omentin-1 levels compared to euthyroid subjects (all p<0.05). TC, LDL-C, and CRP decreased significantly, while NO and omentin-1 levels increased significantly after l-thyroxine replacement. Based on multivariate liner stepwise regression analysis, omentin-1 was independently correlated with BMI and TSH; NO was independently correlated with age, TSH, LDL-C, and omentin-1. High TSH level contributes to endothelial dysfunction in SCH, while TSH-induced decrease of omentin-1 provides a new link between SCH and atherogenic risk.

Subtyping based on readiness and confidence: the identification of help-seeking profiles for gamblers accessing web-based counselling.

BACKGROUND AND AIMS: Problem gamblers are not a homogeneous group and recent data suggest that subtyping can improve treatment outcomes. This study administered three readiness rulers and aimed to identify subtypes of gamblers accessing a national web-based counselling service based on these rulers. METHODS: Participants were 1204 gamblers (99.4% problem gamblers) who accessed a single session of web-based counselling in Australia. Measures included three readiness rulers (importance, readiness and confidence to resist an urge to gamble), demographics and the Problem Gambling Severity Index (PGSI). RESULTS: Gamblers reported high importance of change [mean = 9.2, standard deviation (SD) = 1.51] and readiness to change (mean = 8.86, SD = 1.84), but lower confidence to resist an urge to gamble (mean = 3.93, SD = 2.44) compared with importance and readiness. The statistical fit indices of a latent class analysis identified a four-class model. Subtype 1 was characterized by a very high readiness to change and very low confidence to resist an urge to gamble (n = 662, 55.0%) and subtype 2 reported high readiness and low confidence (n = 358, 29.7%). Subtype 3 reported moderate ratings on all three rulers (n = 139, 11.6%) and subtype 4 reported high importance of change but low readiness and confidence (n = 45, 3.7%). A multinomial logistic regression indicated that subtypes differed by gender (P < 0.001), age (P = 0.01), gambling activity (P < 0.05), preferred mode of gambling (P < 0.001) and PGSI score (P < 0.001). CONCLUSIONS: Problem gamblers in Australia who seek web-based counselling comprise four distinct subgroups based on self-reported levels of readiness to change, confidence to resist the urge to gamble and importance of change.

Pressure induced ionic-superionic transition in silver iodide at ambient temperature.

Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω(-1)cm(-1) could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag(+) ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ∼3.4 × 10(-4)-8.6 × 10(-4) cm(2)/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III'. By analyzing the half infinite length Warburg diffusion process, two parameters α and ß, which closely relate to the disordered state of Ag(+) ions, have been determined and it was suggested that Ag(+) ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω(-1)cm(-1). Evidence for all three, the diffusion coefficient, α and ß, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.

A protective effect of endomorphins on the oxidative injury of islet.

The antioxidative capacity of endomorphins (EMs), endogenous µ-opioid receptor agonists, has been demonstrated by IN VIVO assays. In this study, we attempt to evaluate the effects of endomorphin 1 (EM1) and endomorphin 2 (EM2) on pancreatic islet injuries induced by streptozotocin (STZ), alloxan (ALX) and H(2)O(2), respectively. Wistar rats' islets were isolated and purified. The function of the islet cells, the insulin response to glucose stimulation was examined by insulin Radio Immuno Assay and the cell viability was measured by MTT assay. DNA fragments were performed to evaluate the apoptosis, while the cell cycle distribution was analyzed by PI staining flow cytometric analysis. Furthermore, the islet were treated with EM1, EM2 or ALX for 24 h, and the expression of p53 and p21 protein were determined by Western blot. The results showed that STZ, ALX, and H(2)O(2) displayed clear concentration-dependent inhibitory effects on the pancreatic islet cells. While EMs improved the viability of islet induced by STZ, ALX or H(2)O(2), and EMs enhanced insulin accumulation of the cell supernatant after ALX and STZ stimulation. Our data also showed both that EMs inhibited cell apoptosis and cell cycle G1 arrest induced by STZ and ALX through down-regulaing p53 and p21 expression. Taken together, these results demonstrate that EMs can protect islet cells from STZ, ALX and H(2)O(2) induced injuries. Our observations imply that the endomorphins may have protective effects on islet cells oxidative injury.

The enzymatic basis for the conversion of nonfucosylated to fucosylated alpha-fetoprotein by acyclic retinoid treatment in human hepatoma cells: activation of alpha1-6 fucosyltransferase.

The purpose of the present study was to investigate the mechanism by which nonfucosylated alpha-fetoprotein (AFP) is converted to fucosylated AFP in human hepatoma cell lines exposed to acyclic retinoid (AR), an effective drug for the secondary prevention of hepatocellular carcinoma. AR treatment (100 microM) of HepG2 and Hep3B cells significantly increased the activity and mRNA levels of alpha1-6 fucosyltransferase (alpha1-6 FucT), the enzyme responsible for the fucosylation of AFP, leading to an increase in fucosylated glycoproteins as evidenced by lectin binding measurements. Lectin immunoelectrophoresis of AFP obtained from culture media indicated that the relative percentage of nonfucosylated AFP (L1 fraction) was decreased and alpha1-6 fucosylated AFP (L3 fraction) was increased in these hepatoma cell lines after treatment with AR. The total AFP levels were, however, markedly suppressed by AR treatment, and therefore the absolute L3 fraction on the basis of the total AFP present was extremely low. These results demonstrate that AR enhances the conversion of the L1 to the L3 fraction due to the activation of alpha1-6 FucT in human hepatoma cell lines despite clinical outcome with AR treatment and the L3 fraction of AFP. Even though the dramatic decrease in AFP is the limiting factor in the synthesis of the L3 fraction and, therefore, the absolute value of fucosylated AFP is extremely low, the conversion from L1 to L3 as judged by lectin immunoelectrophoresis represents a good marker for the progress of AR treatment.

High expression of alpha-1-6 fucosyltransferase during rat hepatocarcinogenesis.

Alpha-1-6 fucosylated alpha-fetoprotein (AFP) is known to be elevated in patients with primary hepatoma and has been suggested as being useful as an early indicator and predictor of the poor prognosis for hepatoma. Although GDP-L-fucosyl-N-acetyl-beta-D-glucosaminide alpha-1-6 fucosyltransferase (alpha-1-6 FucT), is the key enzyme involved in alpha-1-6 fucosylation of AFP, when and how the expression of alpha-1-6 FucT is enhanced during hepatocarcinogenesis is unknown. Recently, we established a convenient assay method for this enzyme and were successful in the purification and cDNA cloning of alpha-1-6 FucT from human gastric cancer, as well as from porcine brain. In the present study, levels of alpha-1-6 FucT activity and mRNA expression have been determined during hepatocarcinogenesis in LEC rats which spontaneously develop hereditary hepatitis and hepatoma. The fetal liver contained the highest enzymatic activity, which tended to increase in inverse proportion to gestation. The enzymatic activity was significantly increased in hepatoma tissues as compared with uninvolved adjacent tissues. Northern-blot analysis revealed high expression of alpha-1-6 FucT mRNA in hepatoma tissues, whereas the expression was fairly low in normal, hepatitis and uninvolved adjacent liver tissues. While the fetal liver had the highest enzymatic activity, the expression of alpha-1-6 FucT mRNA was low, suggesting that another alpha-1-6 FucT is induced in fetal liver or that post-translational modification occurs. High expression of alpha-1-6 FucT was also observed in 3'-MeDAB-induced rat hepatomas and some rat hepatoma cell lines. Collectively, alpha-1-6 FucT was strongly enhanced from an early stage of hepatocarcinogenesis and was maintained at a high level in rat hepatomas.

Determination of ZD9583, a thromboxane receptor antagonist, in human plasma and urine by liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry.

A liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCI-MS-MS) method is described for the determination of a thromboxane receptor antagonist (4Z)-6-((2S,4S,5R)-2-(1-(2-cyano-4-methylphenoxy)-1-methylethyl)-4 -(3-pyridyl)-3-dioxan-5-yl)hex-4-enoic acid (ZD9583, I) in human plasma and urine. Proteins in plasma and urine samples are precipitated using acidified acetonitrile. The resulting supernatant is chromatographed on a C8 reversed-phase chromatography column. Following the diversion of the solvent front from the mass spectrometer by a switching valve, the column eluate is passed on to the mass spectrometer via a heated nebulizer interface where the analyte is detected by multiple reaction monitoring (MRM). The method has a chromatographic run time of less than 2 min, a linear calibration curve with a range of 1-500 ng ml(-1) and intra- and inter-day precision estimates of less than 10% over the calibration range.

Purification and cDNA cloning of porcine brain GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase.

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase (alpha1-6FucT; EC 2.4.1.68), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a Triton X-100 extract of porcine brain microsomes. The purification procedures included sequential affinity chromatographies on GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-2Manalpha1- 2)Manbeta1-4GlcNAcbet a1-4GlcNAc-Asn-Sepharose 4B and synthetic GDP-hexanolamine-Sepharose 4B columns. The enzyme was recovered in a 12% final yield with a 440, 000-fold increase in specific activity. SDS-polyacrylamide gel electrophoresis of the purified enzyme gave a major band corresponding to an apparent molecular mass of 58 kDa. The alpha1-6FucT has 575 amino acids and no putative N-glycosylation sites. The cDNA was cloned in to pSVK3 and was then transiently transfected into COS-1 cells. alpha1-6FucT activity was found to be high in the transfected cells, as compared with non- or mock-transfected cells. Northern blotting analyses of rat adult tissues showed that alpha1-6FucT was highly expressed in brain. No sequence homology was found with other previously cloned fucosyltransferases, but the enzyme appears to be a type II transmembrane protein like the other glycosyltransferases.

A fluorescent assay method for GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha 1-6fucosyltransferase activity, involving high performance liquid chromatography.

An assay method for GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha 1-6fucosyltransferase (alpha 1-6FucT; EC 2.4.1.68) activity has been developed, involving a fluorescent pyridylaminated substrate. A glycopeptide derived from bovine gamma-globulin was coupled with 4-(2-pyridylamino)butylamine (PABA) through the peptide bond, and the following substrate was obtained. [equation: see text] The substrate and guanosine diphospho-fucopyranoside (GDP-Fuc) were incubated with a crude enzyme extract for 2 h, and then the enzymatic product was separated by reversed phase HPLC. Quantitation of the product involved measurement of the fluorescence intensity of the fucosylated pyridylaminated sugar. The structures of both synthesized GnGn-bi-Asn-PABA (substrate), and synthesized GnGnF-bi-Asn-PABA (product) were analyzed by 1H NMR. The enzymatic product was also analyzed by 1H NMR and was found to have alpha 1-6fucose at the reducing end GlcNAc. This method is highly specific for alpha 1-6FucT and is applicable for various experiments, including purification and cell culture ones.

[Prevention of septic ventilatory depression with naloxone].

Little is known of the endorphins' role in sepsis-induced respiratory distress and naloxone's effect as a treatment of it. Thirteen piglets were infused with live Escherichia coli at a rate of 2 to 10 x 10(8) colony-forming units per hour for six hours or until death and were divided into two groups: the septic control group (n = 8), and the naloxone-treated group (n = 5), which received 8 mg/kg/h of naloxone by continuous infusion. The results showed a significant reduction of QS/QT, VD/VT, and arterial carbon dioxide pressure at one hour and a significant increase of arterial carbon dioxide pressure and minute ventilation at 1, 3, and 4 hours in the naloxone-treated group, compared with the untreated septic group. None of the piglets in the naloxone-treated group developed ventilatory depression, while 75% of those in the untreated septic group did. Among the latter ficial effects of naloxone are likely related to its action on the central and peripheral respiratory regulatory mechanisms. A transient protection of the cardiac output and relatively decreased extravascular lung water with naloxone treatment may also, in part, improve the ventilation-perfusion maldistribution and secondarily reduce QS/QT and VD/VT.

[Completion pneumonectomy for recurrent lung cancer. Analysis of 59 cases].

From 1973 to 1989, a total of 59 consecutive patients with recurrent lung cancer had completion pneumonectomy. Completion pneumonectomy was done on the right side in 35 patients and left side in 24. The median interval between the first pulmonary resection and completion pneumonectomy for patients was 35 months (5 m-9.5 y). In this series postoperative complications and mortality were comparable to those for routine pneumonectomy. The 1, 3, 5 and 10 year survival rates were 88.5%, 30.2%, 21.4% and 16.7% respectively. None of those patients with histologically proved gross tumor remaining in the hemithorax at the time of reoperation survived longer than 2 years. The authors emphasized that the planning for such an operation must be done meticulously but aggressively. It is obvious that incomplete surgical resection of bronchial carcinoma should be avoided either at initial operation or at completion pneumonectomy because of poor prognosis.

A mixed-bed, multi-derivatization approach using polymeric reagents for derivatizations of amines in high performance liquid chromatographic detection.

Immobilized, polymeric reagents containing covalently attached tagging groups have been synthesized and reacted individually, off-line or on-line, pre-column in high performance liquid chromatographic (HPLC) detection. These reagents have also been combined into a single, mixed-bed reactor, useful for simultaneously preparing several derivatives from a single analyte, all at the same time. Each derivative possesses different chromatographic and detection properties, dependent on the nature of the original polymeric reagent containing the immobilized, tagging species. These particular reagents were designed to impart Ultraviolet/fluorescence, Ultraviolet/electrochemistry (oxidative/reductive or oxidative-hv-electrochemistry) to the final derivatives. Variations in the amounts/ratios of polymeric reagents contained in a single mixed-bed reactor will lead to varying ratios of the final derivatives. These can be predicted knowing the approximate reactivity of each polymeric reagent, percent derivatizations, and overall rates for each reagent towards a given substrate. In this first example of mixed-bed, polymeric reagents for improved derivatization approaches in chromatography, emphasis has been placed on simple amines or amine-like analytes. Multiple derivatives can be effectively used to improve the identification of an unknown analyte in a complex sample matrix, as well as to improve the detectability of that analyte. As one real world application, amphetamine in human urine was quantitated via on-line derivatizations with a mixed-bed reactor. With the least sampling work-up, the resulting sample solutions were directly injected into the on-line derivatization HPLC system for quantitation. The method was validated by single blind spiking experiments. The precision and accuracy were acceptable.

Polymeric dimethylaminopyridinium reagents for derivatization of weak nucleophiles in high-performance liquid chromatography-ultraviolet/fluorescence detection.

This paper introduces a novel polymeric dimethylaminopyridinium 9-fluorenyl-methoxycarbonyl reagent for off-line derivatizations of weak nucleophiles in high-performance liquid chromatography. The method of synthesis and characterization of the polymeric reagent via loading determinations is presented and discussed. Derivatization conditions (solvent, time, and temperature) for primary and secondary alcohols were optimized. As one application, off-line derivatizations of 2-chloro-1-propanol, a potential carcinogen in foodstuffs, were carried out with this polymeric reagent with single-blind and standard addition techniques. A specific sample treatment procedure was also developed. The accuracy and precision of the method were determined and data were statistically evaluated.

Determination of aliphatic amines in air by on-line solid-phase derivatization with HPLC-UV/FL.

An easy, rapid, and efficient method using on-line solid-phase derivatization in HPLC is developed for the trace determination of aliphatic amines in air. Some fundamental studies on stop-flow, on-line, solid-phase derivatizations in HPLC are also investigated, such as optimization of the reaction detection HPLC system and band broadening. Air is sampled with silica gel tubes from different sites, including sewage areas, fish cleaning and processing rooms, and an organoleptic lab of the U.S. Food & Drug Administration (FDA). The trapped amines are desorbed with an acidic aqueous-organic solution, followed by pH adjustment of the eluates to pH 10. The resulting solution is directly injected into an on-line, precolumn, solid-phase derivatization and reversed-phase HPLC-UV/FL system, not requiring any further sample workup steps. The percent derivatizations are as high as 88 +/- 5% (n = 3) for primary amines, and 75 +/- 4% (n = 3) for diethylamine under optimized conditions (60 degrees C for 10 min). The recoveries for all amines are above 90%. The method is validated by a single-blind, spiked experiment with 1.1-4.4% relative standard deviation (RSD) in the range of 15-47 ppm. These results are confirmed by a GC-FID method performed in another lab. Amines are quantitated via calibration plots, with final concentrations from 0.02 to 0.38 mg/m3 air. It is suggested that this newer approach for the determination of amines and polyamines, using polymeric solid-phase reagents on-line, precolumn in HPLC, should prove generally successful for other amines and other sample types in the future.

Polymeric activated ester reagents for off-line and on-line derivatizations of amine nucleophiles in high-performance liquid chromatography with ultraviolet and fluorescence detection.

A novel polymeric activated ester reagent has been developed that improves final detectability and chromatographic performance in high-performance liquid chromatography (HPLC) for virtually all primary and secondary amines or amine analogues. This has involved the synthesis, characterization of final reagent, optimization of derivatization and separation conditions, and determination of analytical figures of merit. The polymeric reagent contained an activated ester linkage to the 9-fluorenyl group, which imparted ultraviolet (UV) and fluorescence (FL) detector properties to the final derivatives. Kinetic studies of these solid-phase (heterogeneous) reactions have been conducted, and specific rate constants were compared with those of the analogous solution reaction for the same substrates. Percent derivatizations have reached 90% and 70% for primary and secondary amines, respectively, under optimized conditions. High reaction reproducibility has been obtained by using the on-line approach, for more than 50 separate injections of the same amine substrate with a single solid-phase reactor. These solid-phase derivatizations have led to detection limits for typical amines in the low-parts-per-billion range. The final, overall methods can provide rapid, automatable, accurate, and precise detection and quantitation of primary/secondary amines and amine-like compounds in real-world sample matrices. As an illustrative example, amphetamine spiked in urine has been derivatized off-line and on-line, with minimum sample preparation, and detected via HPLC-UV/FL with acceptable accuracy and precision.