ABSTRACT
Human T follicular helper (Tfh) cells play a crucial role in orchestrating B cell differentiation, maturation, and immunoglobulin class switching. Recent studies have underscored the presence of Bcl-6 + Tfh cells not only in secondary lymphoid organs but also within tertiary lymphoid structures at inflammatory sites, emphasizing their pivotal role in disease pathogenesis. Furthermore, Tfh cells have been found to transit between lesion sites, lymph nodes, and peripheral blood, as revealed by T cell receptor repertoire analysis. Among Tfh subsets, Tfh2 cells have emerged as central orchestrators in driving the production of IgE and IgG4 from B cells. Their critical role in diseases such as allergy, malignancy, and IgG4-related disease highlights their profound impact on balancing inflammation and immune tolerance. Our current review provides the molecular characteristics of human Tfh cells, the differentiation pathways of Tfh subsets, mechanisms by which Tfh subsets induce IgE and IgG4 production, and their clinical implications in allergy, malignancy, and IgG4-related disease.
ABSTRACT
The gastric stability of eight barbiturates (BARs) (barbital, primidone, allobarbital, phenobarbital, cyclobarbital, pentobarbital, secobarbital, and thiobutabarbital (TBB)) was examined in artificial gastric juice using LC/UV detection. Among the eight BARs, only TBB was degraded at higher temperatures. Furthermore, the degradation product of TBB was isolated, structurally analyzed, and finally identified as 5-butan-2-yl-5-ethyl-1,3-diazinane-2,4,6-trione, also known as butabarbital. The study elucidated that butabarbital was formed by substituting the sulfur atom of the carbonyl group at the 2-position of TBB with an oxygen atom under acidic condition.
Subject(s)
Barbiturates , Gastric Juice , Humans , Barbiturates/chemistry , Drug Stability , Gastric Juice/chemistry , Gastric Juice/metabolism , Molecular Structure , Stomach/chemistryABSTRACT
Alterations in the experience-dependent and autonomous elaboration of neural circuits are assumed to underlie autism spectrum disorder (ASD), though it is unclear what synaptic traits are responsible. Here, utilizing a valproic acid-induced ASD marmoset model, which shares common molecular features with idiopathic ASD, we investigate changes in the structural dynamics of tuft dendrites of upper-layer pyramidal neurons and adjacent axons in the dorsomedial prefrontal cortex through two-photon microscopy. In model marmosets, dendritic spine turnover is upregulated, and spines are generated in clusters and survived more often than in control marmosets. Presynaptic boutons in local axons, but not in commissural long-range axons, demonstrate hyperdynamic turnover in model marmosets, suggesting alterations in projection-specific plasticity. Intriguingly, nasal oxytocin administration attenuates clustered spine emergence in model marmosets. Enhanced clustered spine generation, possibly unique to certain presynaptic partners, may be associated with ASD and be a potential therapeutic target.
Subject(s)
Callithrix , Disease Models, Animal , Neuronal Plasticity , Oxytocin , Animals , Oxytocin/metabolism , Male , Synapses/metabolism , Dendritic Spines/metabolism , Dendritic Spines/pathology , Dendritic Spines/drug effects , Autism Spectrum Disorder/metabolism , Autistic Disorder/metabolism , Autistic Disorder/pathology , Prefrontal Cortex/metabolism , Prefrontal Cortex/pathology , Prefrontal Cortex/drug effects , Pyramidal Cells/metabolism , Pyramidal Cells/pathology , Valproic Acid/pharmacology , Presynaptic Terminals/metabolism , Female , Axons/metabolismABSTRACT
The conventional methamphetamine (MA) detection method using the Simon reaction can be affected by false positives owing to compounds similar to aliphatic secondary amines. In this study, we examined the new Simon reaction to improve the qualitative accuracy of MA detection to discriminate substances that give false positives in a conventional Simon reaction. After the conventional Simon reaction for MA and false positives (N-isopropylbenzylamine (NIP-BA), N-methylbenzylamine (NMe-BA), L-proline (Pro), and L-hydroxyproline (HYP)), which are colored blue, di-tert-butyl dicarbonate (t-Boc) reagent was added, and color tone changes were observed. When t-Boc was added to the false positives (NIP-BA, NMe-BA, Pro, and HYP), the colors of MA, Pro, and HYP changed to purple; NIP-BA changed to blue; and NMe-BA changed to light pink after 3 min. These results suggested that MA can be differentiated from NIP-BA and NMe-BA. Furthermore, the solid-phase chromogenic method was examined, and it was confirmed that MA could be differentiated from Pro and HYP. The method developed in this study should increase the accuracy of MA appraisal at crime scenes and contribute to the reduction of misclassifications arising from false-positive substances.
Subject(s)
Forensic Toxicology , Methamphetamine , Humans , False Positive Reactions , Forensic Toxicology/methods , Central Nervous System Stimulants/analysis , ColorABSTRACT
This study investigates the stability of nitrazepam (NZP), a benzodiazepine drug, under basic conditions, since alkaline putrefactive amines and ammonia are produced once bodies are left to decompose for a long period postmortem after a murder involving NZP or an accidental overdose of NZP. The degradation of NZP in an aqueous alkaline solution was investigated by LC/photodiode array detector (PDA) where the NZP degradation product was isolated and purified by solid-phase extraction using Oasis® MCX, and its chemical structure was determined by LC/time-of-flight (TOF)-MS, NMR spectroscopy, and single-crystal X-ray crystallography. The results revealed that NZP was immediately degraded under basic conditions with 2-amino-5-nitrobenzophenone being an intermediate which further degraded to provide 2-hydroxy-5-nitrobenzophenone as the final degradation product. These results are expected to be useful in clinical chemistry and forensic science, such as the detection of drugs during postmortem examination and suspected addiction.
Subject(s)
Benzodiazepines , Nitrazepam , Magnetic Resonance Spectroscopy , Amines , Hydrolysis , Stomach , Drug Stability , Oxidation-ReductionABSTRACT
GeneFields®-Hair is a simple analysis kit that uses nucleic acid chromatography and polymerase chain reaction (PCR) to identify animal species of hair-like food contaminants. In this study, we evaluated GeneFields®-Hair as a simple and rapid method for identifying animal species from hair-like materials collected in forensic science, such as at crime scenes. The use of this kit with other human biological materials (whole blood, head dandruff, nails, saliva, oral mucosa, sebum, and urine) was also investigated. Animal body hair samples were pretreated by grinding in a buffer solution, centrifuged, and the supernatant was used for PCR. Nucleic acid chromatography of the PCR products allowed the identification of the animal species by the presence or absence of coloration on the decision line. For human biological materials, nucleic acid chromatography was performed after the appropriate pretreatment like body hair material. The determination of some animal species was difficult, even if they had a dedicated DNA Strip determination line. Furthermore, animals from the same family but different genera were sometimes detected on the same determination line. All the human biological samples were correctly identified. Smartphone photographs of the coloration of the judgment line were processed using the ImageJ software for quantitative determination.
Subject(s)
Body Fluids , Nucleic Acids , Animals , Humans , Chromatography , Crime , HairABSTRACT
BACKGROUND: Clenbuterol (CLB) is approved as a veterinary drug because of its tracheal smooth muscle and uterine relaxant effects. However, if improperly administered for the purpose of fattening livestock, CLB can remain in the organs, which may pose a health hazard to humans. OBJECTIVE: We aimed to examine the combination of molecularly imprinted polymer (MIP) and solid-phase dispersive extraction (SPDE) as a pretreatment method for swine liver and kidney, which contain more coexisting impurities than muscle tissue, and attempted to construct an analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: Swine livers and kidneys were homogenized and extracted using liquid-liquid partitioning with an ethyl acetate-n-hexane (1 + 1) mixture, followed by SPDE using an MIP gel, and measured using LC-MS/MS. For LC-MS/MS, either an absolute calibration method or isotope dilution mass spectrometry (IDMS) was used. For method validation, a recovery test (additive concentrations: 0.05 and 0.5 ng/g) was conducted, and the data were analyzed using one-way analysis of variance (ANOVA). RESULTS: The recoveries (trueness), repeatability, and intermediate precision obtained using absolute calibration were similar to those obtained using IDMS. CONCLUSION: Using MIP-SPDE as a pretreatment method for CLB in swine liver and kidney samples yielded comparable results for absolute calibration and IDMS in LC-MS/MS analysis. HIGHLIGHTS: MIP-SPDE can be used as a pretreatment method to analyze CLB in swine organs with high accuracy.
Subject(s)
Clenbuterol , Molecular Imprinting , Humans , Animals , Swine , Chromatography, Liquid , Clenbuterol/analysis , Molecularly Imprinted Polymers/analysis , Chromatography, High Pressure Liquid/methods , Tandem Mass Spectrometry/methods , Polymers/chemistry , Solid Phase Extraction/methods , Liver/chemistry , Kidney , Molecular Imprinting/methodsABSTRACT
The degradation behavior of three benzodiazepines (BZPs)-lormetazepam (LMZ), lorazepam, and oxazepam-with hydroxy groups on the diazepine ring in artificial gastric juice and the effect of storage pH conditions on drug degradability were monitored using an LC/photodiode array detector (PDA) to estimate their pharmacokinetics in the stomach. Although the three BZPs degraded in artificial gastric juice, none could be restored, despite increasing the storage pH, implying that the degradation reaction was irreversible. As for LMZ, we discussed the physicochemical parameters, such as the activation energy and activation entropy involved in the degradation reaction as well as the reaction kinetics; one of the degradation products was isolated and purified for structural analysis. In the LMZ degradation experiment, peaks corresponding to degradation products, (A) and (B), were detected through the LC/PDA measurements. Regarding the degradation behavior, we hypothesized that LMZ was degraded into (B) via (A), where (A) was an intermediate and (B) was the final product. Although the isolation of degradation product (A) was challenging, degradation product (B) could be isolated and was confirmed to be "methanone, [5-chloro-2-(methylamino)phenyl](2-chlorophenyl)-" based on structure determination using various instrumental analyses. The compound exhibited axis asymmetry as determined using single-crystal X-ray structure analysis. Because the formation of degradation product (B) was irreversible, it would be prudent to target the final degradation product (B) and LMZ for identification when detecting LMZ in human stomach contents, such as during forensic dissection.
Subject(s)
Benzodiazepines , Gastric Juice , Humans , Stomach , KineticsABSTRACT
OBJECTIVES: Methotrexate (MTX) is associated with extensive side effects, including myelosuppression, interstitial pneumonia, and infection. It is, therefore, critical to establish whether its administration is required after achieving remission with tocilizumab (TCZ) and MTX combination therapy in patients with rheumatoid arthritis (RA). Therefore, the aim of this multicenter, observational, cohort study was to evaluate the feasibility of MTX discontinuation for the safety of these patients. METHODS: Patients with RA were administered TCZ, with or without MTX, for 3 years; those who received TCZ+MTX combination therapy were selected. After remission was achieved, MTX was discontinued without flare development in one group (discontinued [DISC] group, n = 33) and continued without flare development in another group (maintain [MAIN] group, n = 37). The clinical efficacy of TCZ+MTX therapy, patient background characteristics, and adverse events were compared between groups. RESULTS: The disease activity score in 28 joints-erythrocyte sedimentation rate (DAS28-ESR) at 3, 6, and 9 months was significantly lower in the DISC group (P < .05, P < .01, and P < .01, respectively). Further, the DAS28-ESR remission rate at 6 and 9 months and Boolean remission rate at 6 months were significantly higher in the DISC group (P < .01 for all). Disease duration was significantly longer in the DISC group (P < .05). Furthermore, the number of patients with stage 4 RA was significantly higher in the DISC group (P < .01). CONCLUSIONS: Once remission was achieved, MTX was discontinued in patients who responded favorably to TCZ+MTX therapy, despite the prolonged disease duration and stage progression.
Subject(s)
Antirheumatic Agents , Arthritis, Rheumatoid , Humans , Methotrexate/adverse effects , Antirheumatic Agents/adverse effects , Cohort Studies , Feasibility Studies , Drug Therapy, Combination , Arthritis, Rheumatoid/drug therapy , Treatment OutcomeABSTRACT
We have developed a fluorescence detection-liquid chromatography (HPLC-FL) method that involves sample pretreatment by solid-phase dispersive extraction (SPDE) and solid-phase fluorescence derivatization for the simple and rapid analysis of methamphetamine (MA) in urine. This method uses a reversed-phase polymeric solid-phase gel to clean up analytes in SPDE, followed by fluorescence derivatization with 9-fluorenylmethyl chloroformate (FMOC) in the solid-phase. The optimal conditions for SPDE and solid-phase fluorescence derivatization were obtained when J-SPEC PEP was used as the solid-phase gel and 0.5 mmol/L FMOC in 50 mmol/L borate buffer solution (pH 10) was used as the fluorescence derivatization reagent. The recovery experiment of MA in urine yielded a clean chromatogram with no interfering peaks, demonstrating the validity of our method; the recoveries were 83.6% when spiked at a low concentration level (100 ng/mL) and 80.7% when spiked at a high concentration level (1000 ng/mL). Compared with the conventional liquid-phase method, the reaction product (FMOC-MA) of solid-phase fluorescence derivatization had higher stability. Reaction rate constants were calculated by changing the temperature conditions, and physicochemical parameters, including activation energy and activation entropy involved in the degradation reaction, were obtained from the Arrhenius plot and analyzed thermodynamically. Taken together, our results suggest that the HPLC-FL method with SPDE and solid-phase fluorescence derivatization for sample pretreatment provides a simple and rapid means of analyzing MA in urine samples.
Subject(s)
Methamphetamine , Methamphetamine/urine , Chromatography, High Pressure Liquid/methods , Chromatography, LiquidABSTRACT
In this study, we focused on ultra-weak chemiluminescence (uwCL) measurements and aimed to develop a blood detection method at trace levels, that are difficult to observe using a conventional luminol reaction method (visual observation). Furthermore, we investigated sampling methods that could detect trace bloodstains from the field in our laboratory settings. To achieve these highly sensitive detection levels in the uwCL measurements, the optimal measurement conditions were established as follows: the luminol reaction solution chosen was a mixture of 6.0 × 10-3% luminol/1.5 × 10-2% sodium hydroxide solution and 1.5 × 10-2% hydrogen peroxide water (6:1); the temperature in the sample chamber was set to 20 °C; the sample chamber was filled with an oxygen displacement atmosphere; the sample chamber was filled with 3 mL of 0.01% sodium hydroxide solution prior to the experiment, and the measurement wavelength was set to 460 nm. Using the developed method, blood diluted to 12.5 million-fold (8.0 ng equivalent of the absolute weight of whole blood) was detectable, and high linearity (r = 0.9986) between uwCL intensity and whole blood equivalent was observed in the range of 8.0-100 ng. In contrast, the detection limit of the conventional method was 1.0 µg of the whole blood equivalent. Thus, the uwCL method was approximately 125 times more sensitive than the conventional method. In addition, we demonstrated that the sampling method of wiping with a melamine sponge soaked in a 10% sodium dodecyl sulfate solution is effective for sampling evidence materials at an appraisal site suspected of having traces of adhered blood.
Subject(s)
Luminescence , Luminol , Sodium Hydroxide , Water , Luminescent Measurements/methods , Hydrogen PeroxideABSTRACT
Induced mutation is a viable breeding strategy that is widely utilized in the development of elite plant varieties. We aimed to improve a variety of edamame by constructing novel mutant populations using the ethyl methanesulfonate in soybeans (Glycine max (L.) Merr.). In the M2 population, the flowering stage showed a considerable standard deviation compared to the wild type, confirming that the mutant populations had the expected DNA mutations. To identify the DNA mutations in the mutant populations, we used the targeting induced local lesions in genomes (TILLING) method, which is a reverse genetic method, to search for soybean flowering-related gene mutants. A total of 30 mutants from E1, E3, E4, and PhyA1 genes, which are known to be highly effective genes, or their homologous gene for flowering and maturation found in soybean quantitative trait locus analyses were isolated from our TILLING screening. Among these mutants, there were eleven nonsynonymous substitution mutants, one nonsense mutant, and two single nucleotide deletion mutants that could be expected to reduce or eliminate gene function. The e1, e3, and e4 mutants obtained in this study flowered considerably earlier than the wild type. In particular, the e1 mutant with a nonsynonymous substitution flowered approximately 1 month after sowing regardless of the sowing date, and its harvest date was approximately 1 month earlier than that of the wild type. Mutations identified using the TILLING method could not only be used as gel-based DNA markers with the same manipulation method, but the mutations could also be detected as DNA markers by the high-resolution melting method. These results indicate that mutations achieved without chromosome modification by crossbreeding are effective for early and practical improvement of superior varieties and that efficient selection of mutants by reverse genetics is an effective method for the identification of genetic modifications. The edamame mutant populations developed in this study are believed to possess various useful alleles which may be applicable in the search for mutations that lead to improved edamame yield and eating quality beyond the flowering stage.
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Chylothorax is a rare but life-threatening condition in neonates. We herein report the successful use of OK-432 for a low-birth-weight infant with trisomy 18 who developed refractory chylothorax after thoracic surgery. Increasing the concentration of OK-432 seems useful in cases with a lot of pleural effusion.
ABSTRACT
BACKGROUND: Living donor liver transplantation (LDLT) has been actively performed for patients with poor clearance of jaundice after the Kasai operation for biliary atresia (BA). The present study clarified the usefulness of LDLT for BA. MATERIALS AND METHODS: Between 2000 and 2020, 24 patients (late group) underwent radical surgery for BA in our institute. The overall survival rate, native liver survival rate, and proportion of LDLT in the late group were retrospectively compared with those of 47 patients treated before 1999 (early group). P values <.05 was considered statistically significant. RESULTS: The overall survival rates at 5, 10, and 15 years were 57%, 54%, and 49%, respectively, in the early group and 100%, 100%, and 100% in the late group (P < .001). The native liver survival rates at 5, 10, and 15 years were 57%, 52%, and 39%, respectively, in the early group and 57%, 49%, and 42% (P = .993) in the late group. In the early group, LDLT was performed in 7 of 47 patients (15%), and the overall survival rate after LDLT was 71%. In the late group, LDLT was performed in 11 of 24 patients (46%), and the overall survival rate after LDLT was 100%. CONCLUSIONS: The long-term outcomes after the Kasai operation for BA have improved in recent years. There were no marked differences in long-term native liver survival before and after 2000. LDLT was actively introduced for patients with poor clearance of jaundice after the Kasai operation, and the survival rate significantly improved.
Subject(s)
Biliary Atresia , Liver Transplantation , Biliary Atresia/surgery , Humans , Infant , Liver Transplantation/adverse effects , Living Donors , Portoenterostomy, Hepatic/adverse effects , Retrospective Studies , Treatment OutcomeABSTRACT
BACKGROUND: The aim was to assess the therapeutic strategy of patients with chylothorax in a neonatal intensive care unit. METHODS: Twenty-eight infants with chylothorax were included in this study. Their clinical characteristics and outcomes were reviewed retrospectively. RESULTS: The male-to-female ratio was 1:1. The mean gestational age and birthweight were 35.1 ± 3.5 weeks and 2,692 ± 791 g, respectively. Eighteen patients were diagnosed with congenital chylothorax; chylothorax occurred postoperatively in 10 patients. Chromosomal anomalies were diagnosed in 8 patients. Six patients received surgical therapy, such as pleurodesis, thoracic duct ligation, or lymphaticovenous anastomosis. Two patients required surgery due to resistance to pleurodesis. In surgically managed patients, the daily maximum amount of pleural effusion (mL)/bodyweight (kg) ratio was significantly larger than in non-surgically managed patients: 229.0 ± 180.5 versus 59.7 ± 49.2 mL/kg. In the receiver operating characteristic analysis of the daily maximum amount of pleural effusion/bodyweight ratio, the area under the curve was 0.889 when the cut-off value was 101 mL/kg, and the sensitivity was 0.8333 and the specificity was 0.8095 (P = 0.0059). CONCLUSIONS: Pleurodesis using OK432 could become a surgical first-line therapy for chylothorax even for neonates. It was important to initiate pleurodesis for refractory chylothorax at an earlier stage. A daily chylous effusion/bodyweight ratio of >101 mL/kg was a good predictor and seemed to be a useful parameter for prompt surgical intervention.
Subject(s)
Chylothorax , Pleural Effusion , Chylothorax/diagnosis , Chylothorax/etiology , Chylothorax/surgery , Female , Humans , Infant , Infant, Newborn , Intensive Care Units, Neonatal , Male , Pleural Effusion/diagnosis , Pleural Effusion/etiology , Pleural Effusion/therapy , Pleurodesis , Retrospective StudiesABSTRACT
Autism spectrum disorder (ASD) is a multifactorial disorder with characteristic synaptic and gene expression changes. Early intervention during childhood is thought to benefit prognosis. Here, we examined the changes in cortical synaptogenesis, synaptic function, and gene expression from birth to the juvenile stage in a marmoset model of ASD induced by valproic acid (VPA) treatment. Early postnatally, synaptogenesis was reduced in this model, while juvenile-age VPA-treated marmosets showed increased synaptogenesis, similar to observations in human tissue. During infancy, synaptic plasticity transiently increased and was associated with altered vocalization. Synaptogenesis-related genes were downregulated early postnatally. At three months of age, the differentially expressed genes were associated with circuit remodeling, similar to the expression changes observed in humans. In summary, we provide a functional and molecular characterization of a non-human primate model of ASD, highlighting its similarity to features observed in human ASD.
Subject(s)
Autism Spectrum Disorder/physiopathology , Disease Models, Animal , Evoked Potentials/physiology , Neurons/physiology , Prefrontal Cortex/physiology , Synaptic Transmission/physiology , Animals , Autism Spectrum Disorder/chemically induced , Autism Spectrum Disorder/genetics , Callithrix , Dendritic Spines/physiology , Electric Stimulation , Gene Expression Profiling/methods , Humans , Neuronal Plasticity/genetics , Neuronal Plasticity/physiology , Neurons/metabolism , Oligonucleotide Array Sequence Analysis/methods , Patch-Clamp Techniques/methods , Prefrontal Cortex/cytology , Prefrontal Cortex/metabolism , Valproic AcidABSTRACT
BACKGROUND: The antegrade continence enema (ACE) procedure is effective for severe constipation in patients with spina bifida and can improve quality of life (QOL). The Monti-Malone procedure (MM), which is a method of creating an enema tract from the colon, has been reported as an alternative to the ACE procedure when the appendix cannot be used. We report the usefulness of MM as a reconstruction of the antegrade continence enema procedure. CASE PRESENTATION: Our patient was a 22-year-old man with congenital spina bifida and hydrocephalus. Ventriculoperitoneal (VP) shunt surgery was performed immediately after birth, and preventative appendectomy was carried out during VP shunt repair when 4 months old. At 5 years of age, the ACE procedure using a balloon-button gastrostomy tube was performed for intractable chronic constipation. Simple management was expected, but after 17 years of age, he experienced increased stool leakage around the gastrostomy tube and his QOL declined due to difficulty in managing the ACE. Therefore, reconstruction of the ACE procedure by MM was performed. After reconstruction, the ACE performed well without any complications. The patient is currently satisfied because management of the ACE is easier than before, and his QOL has markedly improved without stool leakage and dermatitis. CONCLUSIONS: MM is less likely to cause complications and is useful as a reconstruction of the ACE procedure.
ABSTRACT
The degradation behavior of eight benzodiazepines (BZPs): alprazolam, etizolam, diazepam, triazolam, nitrazepam (NZP), flunitrazepam (FNZ), bromazepam, and lorazepam, in artificial gastric juice was monitored by a LC/photodiode array detector (PDA) to estimate their pharmacokinetics in the stomach. For drugs that were degradable, such physicochemical parameters as reaction rate constant were measured to evaluate the effect of storage conditions on drug degradability, such as whether the degradation proceeds faster by increasing storage temperature, or whether the degradation reaction is reversible by adjusting pH. As a result, it was confirmed that although the eight BZPs degraded in artificial gastric juice, most of them could be restored when pH was increased, and the restoration rates differed depending on the pH and the type of BZP. As for NZP, an Arrhenius plot was drawn to obtain the physicochemical parameters, such as activation energy and activation entropy involved in the degradation reaction, and the reaction kinetics was discussed. In addition, two substances were confirmed as the degradation products of NZP in artificial gastric juice: one was a reversible degradation product (A) (intermediate) and the other was an irreversible degradation product (B) (final degradation product). The intermediate was identified as 2-amino-N-(2-benzoyl-4-nitrophenyl)-acetamide, and the final degradation product was 2-amino-5-nitrobenzophenone. Therefore, when detecting NZP in human stomach contents, such as during judicial dissection, it would be prudent to target NZP as well as the intermediate (A) and the final degradation product (B).
Subject(s)
Benzodiazepines/chemistry , Gastric Juice/chemistry , Nitrazepam/chemistry , Acids/chemistry , Benzophenones/chemistry , Chromatography, High Pressure Liquid , Drug Stability , Humans , Hydrolysis , Pharmaceutical Preparations/chemistry , Stomach , Tandem Mass SpectrometryABSTRACT
BACKGROUND: Aflatoxins (AFs) are carcinogenic mycotoxins. A simple, quick, and accurate method for the micro-analysis of AFs in foodstuffs, especially spices, is needed. OBJECTIVE: A sophisticated pretreatment method that combines solid-phase dispersive extraction (SPDE) and solid-phase fluorescence derivatization using immunoaffinity (IA) gel as the solid phase was developed to analyze AFs in spices simply, quickly, and sensitively by liquid chromatography with fluorescence detection. METHOD: White and black pepper samples were extracted with a mixed solution of methanol/water (4:1) and then diluted with 7% aqueous solution of Triton-X. The solution was subjected to cleanup by SPDE using IA gel. Trifluoroacetic acid was added to the IA gel for on-site solid-phase fluorescence derivatization. RESULTS: Chromatograms containing well-separated peaks and few interference peaks from contaminants were obtained. The method detection limit of AFs in white and black pepper was 0.15-0.29 ng/g. Repeatability and intermediate precision were <10% and <15%, respectively, and accuracy was 61.7-87.8%. In addition, inter-laboratory precision was <29% and mean recovery was 61.5-76.7%. A favorable z-score of |Z| ⦠1 was obtained in seven laboratories, although one laboratory gave 2 < |Z| < 3. CONCLUSIONS: The validity, reliability, practicality, and robustness of the developed method were verified. HIGHLIGHTS: By using SPDE and solid-phase fluorescence derivatization in combination for AF analysis, fluorescence derivatization during cleanup was realized, leading to simplification of the pretreatment operation.
Subject(s)
Aflatoxins , Chromatography, High Pressure Liquid , Spices , Aflatoxins/analysis , Reproducibility of Results , Solid Phase ExtractionABSTRACT
The degradation behavior of eight tricyclic antidepressants (TCAs; amitriptyline, amoxapine (AMX), imipramine, clomipramine, desipramine, doxepin, dothiepin, and nortriptyline) in artificial gastric juice was investigated to estimate their pharmacokinetics in the stomach. As a result, among the eight TCAs, only AMX was degraded in artificial gastric juice. The degradation was a pseudo first-order reaction; activation energy (Ea) was 88.70 kJ/mol and activation entropy (ΔS) was -80.73 J/K·mol. On the other hand, the recovery experiment revealed that the degradation product did not revert to AMX and accordingly, this reaction was considered to be irreversible. In the AMX degradation experiment, peaks considered to be degradation products A (I) and B (II) were detected at retention times of around 3 min and 30 min in LC/UV measurements, respectively. Structural analysis revealed that compound (I) was [2-(2-aminophenoxy)-5-chlorophenyl]-piperazin-1-yl-methanone, a new compound, and compound (II) was 2-chlorodibenzo[b,f][1,4]oxazepin-11(10H)-one. As for the degradation behavior, it was estimated that AMX was degraded into (II) via (I), i.e., (II) was the final product. The results are expected to be useful in clinical chemistry and forensic science, including the estimation of drugs to be used at the time of judicial dissection and suspected drug addiction.