Simultaneous determination of fenthion and its metabolites in a case of fenthion self-poisoning.

Fenthion (MPP) is a popular organophosphorus pesticide that acts via inhibition of the enzyme cholinesterase. It is well known that fenthion is metabolized by plants, animals and soil microorganisms to sulfone and sulfoxide by oxidation of thioether and is further metabolized by conversion of P = S to P = O (oxon). Although human fenthion poisonings sometimes occur, details of the distribution of fenthion and its metabolites within the bodies of victims are unclear.

Quantification of nine psychotropic drugs in postmortem dried blood spot samples by liquid chromatography-tandem mass spectrometry for simple toxicological analysis.

Dried blood spot (DBS) sampling has evolved to become the method of choice for collecting samples for newborn screening and therapeutic drug monitoring worldwide. The major advantage of this approach is that it requires only a small amount of blood. In addition, the collection of DBSs on filter paper is simple, sample storage costs are small, and the process deactivates microorganisms and viruses.

Relationships between cause of death and concentrations of seven steroids obtained from the serum and cerebrospinal fluid of cadavers.

In this study, we assessed 80 autopsy samples to investigate the relationships between cause of death and the concentrations of multiple steroids in serum and cerebrospinal fluid (CSF). First, we developed and validated analytical methods to quantify seven steroids (cortisol, cortisone, corticosterone, 11-deoxycortisol, 11-deoxycortiocosterone, progesterone, and testosterone) by using liquid chromatography coupled with electrospray ionization-tandem mass spectrometry. Next, we statistically evaluated the levels of each steroid for six causes of death: hypothermia, traumatic injury, fire fatality, asphyxia, intoxication, and internal disease.

Quantification of cyanide metabolite 2-aminothiazoline-4-carboxylic acid in postmortem dried blood spot samples by liquid chromatography-tandem mass spectrometry.

2-Aminothiazoline-4-carboxylic acid (ATCA), which is produced by the reaction of cyanide with endogenous cystine, is a promising biomarker of cyanide exposure because of its physicochemical stability. Analysis of more stable metabolite than the toxic gas itself is sometimes useful for postmortem diagnosis of gas poisoning. Here, we developed and validated an approach that uses liquid chromatography coupled with electrospray ionization-tandem mass spectrometry for quantifying ATCA in dried blood spot (DBS) samples.

Assessment of blood 2-aminothiazoline-4-carboxylic acid concentrations: Age and sex differences, and correlation with carboxyhemoglobin in fire victims.

Recently, 2-aminothiazoline-4-carboxylic acid (ATCA), a cyanide (CN) metabolite, has been proposed as a stable diagnostic marker of CN poisoning. In this study, liquid chromatography coupled with electrospray ionization - tandem mass spectrometry was used to quantify ATCA concentrations in human postmortem blood samples, and differences in ATCA concentrations according to age and sex were determined. Both age and sex had significant effects on blood ATCA concentrations.

ACE2 immunohistochemistry in salivary and tracheal glands related to age.

Objective: SARS-CoV-2 is the cause of COVID-19, the rapidly spreading pandemic. When SARS-CoV-2 enters the target cells in the respiratory system, the spike glycoprotein binds to a cellular receptor angiotensin converting enzyme 2 (ACE2). The susceptibility to infection in individuals under 20 years of age is approximately half that of adults aged over 20 years.

Simultaneous quantification by LC/ESI-MS/MS of chlorinated tyrosine derivatives in the autopsy sample of a victim of chlorine exposure.

Direct detection and accurate quantification of chlorine in autopsy samples are difficult because of the volatility and rapid metabolism of chlorine. Here, we developed and validated a method for quantitative analysis of 3-chloro-l-tyrosine (Cl-Tyr) and 3,5-dichloro-l-tyrosine (DiCl-Tyr) as stable markers of chlorine exposure. Chemical derivatization followed by liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) enabled us to simultaneously analyze both Cl-Tyr and DiCl-Tyr in an autopsy sample from the victim of chlorine exposure.

Development of an LC-MS/MS method for quantification of 3-chloro-L-tyrosine as a candidate marker of chlorine poisoning.

A simple and sensitive liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for the determination of 3-chloro-L-tyrosine (Cl-Tyr) was developed and validated. For sample preparation, 50 μL of the body fluids or tissue extracts were processed by protein precipitation followed by the derivatization with dansyl chloride. The calibration curve was linear over the concentration range of 2.

A fatal poisoning case of acetone cyanohydrin and citalopram.

Acetone cyanohydrin (ACH) is a readily available source of cyanide and is widely used in basic and applied sciences. In toxicology, ACH is classified as extremely hazardous as it readily decomposes on contact with water, with the potential rapid release of highly toxic hydrogen cyanide (HCN). We report the case of a young woman found dead from the intentional ingestion of ACH and citalopram, an antidepressant of the selective serotonin reuptake inhibitor class.

Hyperketonemia as the diagnostic basis for hypothermia: An experimental study in diabetic and control mice.

Hypothermia is an important cause of death in forensic pathology. For the forensic diagnosis of hypothermia, some reports point out the possibility that hypothermia without diabetes may cause ketoacidosis. In this study, we evaluated the diagnostic value of ketoacidosis in a murine model of hypothermia, using the cold stress at 4 °C for 3 or 5 hrs in genetically diabetic (BKS.

Immunohistochemistry of advanced glycation end product N-(carboxymethyl)lysine in coronary arteries in relation to cardiac fibrosis and serum N-terminal-pro basic natriuretic peptide in forensic autopsy cases.

Objective: Advanced glycation end products (AGEs) are known to play important roles in the development of diabetes mellitus and atherosclerosis.　N-(carboxymethyl)lysine (CML) is the major AGE, and is found in the arterial walls in the heart. The CML involvement in myocardial ischemia has been reported.

Ror2 signaling regulates Golgi structure and transport through IFT20 for tumor invasiveness.

Signaling through the Ror2 receptor tyrosine kinase promotes invadopodia formation for tumor invasion. Here, we identify intraflagellar transport 20 (IFT20) as a new target of this signaling in tumors that lack primary cilia, and find that IFT20 mediates the ability of Ror2 signaling to induce the invasiveness of these tumors. We also find that IFT20 regulates the nucleation of Golgi-derived microtubules by affecting the GM130-AKAP450 complex, which promotes Golgi ribbon formation in achieving polarized secretion for cell migration and invasion.

Effect of polymer containing a naphthyl-alanine derivative on the separation selectivity for aromatic compounds in temperature-responsive chromatography.

A novel polymer-grafted stationary phase of high-performance liquid chromatography (HPLC) was developed, utilizing a temperature-responsive polymer containing an aromatic moiety. Firstly, we synthesized novel functional polymer poly(N-isopropylacrylamide-co-N-acryloyl-3-(2-naphthyl)-L-alanine methyl ester) [poly(NIPAAm-co-Nap)], which has temperature-responsiveness and selective retention of aromatic compounds by an intermolecular π-π interaction. The polymer exhibited a significant reversible phase transition from hydrophilic to hydrophobic in the vicinity of its lower critical solution temperature.

Reaction monitoring of tocopherols with active nitrogen oxides by ultra high-speed liquid chromatography.

Ultra high-speed liquid chromatography (LC) has become increasingly popular in analytical research fields. This analytical system provides fast and efficient chromatographic separation over a wide range of flow rate and pressure. In this study, we applied an ultra high-speed LC system to monitor the reaction of α-, γ-, and δ-tocopherols with active nitrogen species.

Separation of phosphorylated peptides utilizing dual pH- and temperature-responsive chromatography.

The phosphorylation of a peptide is considered to be one of the most important post-translational modification reactions that can alter protein function in mammalian cells. To separate and purify, we developed a dual temperature- and pH-responsive chromatography based on terpolymer composed of N-isopropylacrylamide, N,N'-dimethylaminopropylacrylamide and butylmethacrylate. The property of the surface of the terpolymer-grafted stationary phase altered from hydrophilic to hydrophobic, and from changed to non-charged by changes in the temperature and the pH, respectively.

Dual temperature- and pH-responsive fluorescence molecular probe for cellular imaging utilizing a PNIPAAm-fluorescein copolymer.

The thermally controlling fluorescence intensity of a molecular probe for cellular imaging has been investigated. A reversible temperature-induced phase transition of N-isopropylacrylamide/fluorescein copolymers [poly(NIPAAm-co-FL)] was used as a molecular switch to control the fluorescence intensity of the imaging probe. The copolymer displayed environmentally sensitive fluorescence properties, in which the fluorescence intensity changed with the response to both the temperature and the pH.

"Cleavable" hapten-biotin conjugates: preparation and use for the generation of anti-steroid single-domain antibody fragments.

Antibody engineering technology has the potential to provide artificial antibodies with higher performance than conventional antibodies. Filamentous phage particles are often used to express a vast diversity of mutated antibody fragments from which clones displaying improved fragments can be isolated. We recently showed that hapten-biotin conjugates, combined via a linker involving a reductively cleavable disulfide bond, are useful for isolating phage clones displaying high-affinity anti-hapten antibody fragments.

Aqueous chromatographic system for the quantification of propofol in biological fluids using a temperature-responsive polymer modified stationary phase.

A new method for the quantitative analysis of monkey serum propofol, which is widely used as an anaesthetic agent, was developed by utilizing a temperature-responsive polymer of N-isopropylacrylamide (NIPAAm) and butyl methacrylate (BMA) as the stationary phase of HPLC-fluorescence detection. This poly(NIPAAm-co-BMA) copolymer undergoes a reversible phase transition from a hydrophilic to a hydrophobic microstructure when triggered by change in the temperature. Also this chromatographic system is possible to separate the analytes by using only water as a mobile phase.

Studies on neurosteroids XXIV. Determination of neuroactive androgens, androsterone and 5alpha-androstane-3alpha,17beta-diol, in rat brain and serum using liquid chromatography-tandem mass spectrometry.

The development and validation of liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-ESI-MS/MS) methods that enable the quantification of neuroactive androgens, androsterone (5alpha-androstan-3alpha-ol-17-one, 3alpha,5alpha-A) and 5alpha-androstane-3alpha,17beta-diol (3alpha,5alpha-Adiol), in the rat brain and serum are presented. The androgens were extracted with methanol-acetic acid, purified using solid-phase extraction cartridges, derivatized with an ESI-active reagent, isonicotinoyl azide (INA), and then subjected to LC-ESI-MS/MS. The quantifications were based on selected reaction monitoring mode using the characteristic transitions of the INA derivatives.

Characterization of in vivo metabolites of toad venom using liquid chromatography-mass spectrometry.

The structures of in vivo metabolites of marinobufotoxin (marinobufagin 3-suberoylarginine ester), marinobufagin, or bufalin which are typical components of toad venom widely used as the traditional Chinese drug, Ch'an Su, are confirmed using authentic samples based on their liquid chromatography-mass spectrometric behavior. A rat is orally administered 2 mg of the previously mentioned components of toad venom, the serum is collected 30 min after the administration, extracted, and then characterized. Marinobufotoxin is hydrolyzed and further epimerized into 3-epimarinobufagin, but marinobufagin 3-hemisuberate is not detected.

Simultaneous determination of 17alpha-hydroxypregnenolone and 17alpha-hydroxyprogesterone in dried blood spots from low birth weight infants using LC-MS/MS.

17alpha-hydroxypregnenolone (17OHPreg) has heretofore been considered to be the major cause of the false elevated 17alpha-hydroxyprogesterone (17OHP) value in the immunoassay-based newborn screening for congenital adrenal hyperplasia (CAH). To verify this point, we developed a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method that enables the simultaneous quantification of 17OHPreg and 17OHP in the dried blood filter papers and measured their blood levels in infants, especially in infants with low birth weights. Steroids were extracted from the filter papers with methanol, purified using a Strata-X cartridge, derivatized with 2-hydrazinopyridine and subjected to LC-MS/MS.