Evaluation of Ischemic Time and Complications in Free Jejunum Transfer.

BACKGROUND: In free jejunum transfer, knowing the ischemic tolerance time of the jejunum is crucial. It helps determine the need for reharvesting if an unexpected situation prolongs the ischemic time. The current ischemic tolerance time in humans is unknown. We investigated the relationship between ischemic time and postoperative complications in head and neck cancer patients who underwent free jejunum transfer. METHODS: The study included 76 patients with available medical records out of 103 patients who underwent free jejunum transfer between 2009 and 2023. The association between the surgical procedure, including ischemic time, and patient's background, and flap engraftment, stenosis of the intestinal anastomosis, the swallowing function, and other complications was investigated. RESULTS: The ischemic time for jejunal flaps ranged from 1 h 24 min to 6 h, with a mean of 197 ± 55.5 min. In 72 patients, the jejunum was successfully engrafted, but vascular occlusion occurred in another four patients. In three of these patients, jejunal necrosis occurred, and there was no specific trend in ischemic time. Stenosis of the intestinal anastomosis occurred in 17 cases (22%), with ischemic time (≥3 h) and age (≥75 years) being significant factors for stenosis (ischemic time: 30% vs. 10%, p = 0.048, age: 50% vs. 15%, p < 0.01). No significant correlations were observed with other complications or the swallowing function. CONCLUSION: There was no specific trend between ischemic time and jejunal survival rate, indicating that an ischemic time within 6 h may not have affected engraftment. Although we have recently performed intestinal anastomosis prior to vascular anastomosis, the choice of surgical technique should be adapted to the patient's age and background.

The new live imagers MitoMM1/2 for mitochondrial visualization.

Mitochondria are eukaryotic organelles that consist of outer and inner bilayer membranes with a positive potential (H+) in the intermembrane space. This organelle plays an important role in ATP production and apoptosis. To observe the mitochondria in living cells, several fluorescent dyes (such as MitoTracker® [a standard mitochondrial imager] or rhodamine 123) have been developed. However, these reagents are unstable and exhibit a wide range of emission spectra, thereby hampering double staining results. Using recombinant DNA techniques, green or red fluorescent protein (GFP or RFP)-tagged proteins are now available for multi-color labeling of mitochondria. Here, we have discussed the development of the novel mitochondrial live imagers MitoMM1/2, derivatives of ATTO565; furthermore, MitoMM1/2 are sensitive to the membrane potential, resistant to detergents, and the fluorescence of MitoMM1/2 does not overlap with green fluorescence.

Impact of antiplatelet therapy on tissue prolapse at super acute phase after stenting: serial OCT study in acute coronary syndrome patients.

Although drug-eluting stents have improved clinical outcomes, percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) remains a challenging procedure in terms of thrombus management. A new-generation P2Y12 receptor inhibitor, prasugrel, provides more rapid and potent antiplatelet action compared with clopidogrel. Prasugrel achieved significant reduction of ischemic events compared with clopidogrel in ACS. The aim of this optical coherence tomography (OCT) study was to evaluate temporal changes in tissue prolapse after stenting under different antiplatelet regimens (aspirin plus prasugrel or clopidogrel) in ACS patients. A total of 119 ACS patients were randomized to either prasugrel or clopidogrel at the time of PCI. OCT analysis was available in 119 patients at baseline (just after stenting), 77 patients at 2 weeks, and 62 patients at 4 months after stenting. Cross-sectional analysis for every 1 mm was performed at in-stent and adjacent reference segment. Tissue prolapse area was calculated by lumen area minus stent area within the stented segment. Baseline patient and procedural characteristics were not different between the prasugrel and clopidogrel groups. Tissue prolapse area was significantly lower in the prasugrel compared with the clopidogrel group after stenting (0.24 ± 0.23 vs. 0.36 ± 0.23 mm2, p = 0.003) and at 2 weeks (0.11 ± 0.13 vs. 0.19 ± 0.16 mm2, p = 0.005). However, there was no significant difference at 4 months. In conclusion, our study suggests prasugrel was effective in reducing tissue prolapse in the super acute phase in ACS patients compared with clopidogrel. However, the effect of tissue prolapse reduction was not different up to 4 months follow-up.

14-3-3εa directs the pulsatile transport of basal factors toward the apical domain for lumen growth in tubulogenesis.

The Ciona notochord has emerged as a simple and tractable in vivo model for tubulogenesis. Here, using a chemical genetics approach, we identified UTKO1 as a selective small molecule inhibitor of notochord tubulogenesis. We identified 14-3-3εa protein as a direct binding partner of UTKO1 and showed that 14-3-3εa knockdown leads to failure of notochord tubulogenesis. We found that UTKO1 prevents 14-3-3εa from interacting with ezrin/radixin/moesin (ERM), which is required for notochord tubulogenesis, suggesting that interactions between 14-3-3εa and ERM play a key role in regulating the early steps of tubulogenesis. Using live imaging, we found that, as lumens begin to open between neighboring cells, 14-3-3εa and ERM are highly colocalized at the basal cortex where they undergo cycles of accumulation and disappearance. Interestingly, the disappearance of 14-3-3εa and ERM during each cycle is tightly correlated with a transient flow of 14-3-3εa, ERM, myosin II, and other cytoplasmic elements from the basal surface toward the lumen-facing apical domain, which is often accompanied by visible changes in lumen architecture. Both pulsatile flow and lumen formation are abolished in larvae treated with UTKO1, in larvae depleted of either 14-3-3εa or ERM, or in larvae expressing a truncated form of 14-3-3εa that lacks the ability to interact with ERM. These results suggest that 14-3-3εa and ERM interact at the basal cortex to direct pulsatile basal accumulation and basal-apical transport of factors that are essential for lumen formation. We propose that similar mechanisms may underlie or may contribute to lumen formation in tubulogenesis in other systems.

Single amino acid mutation altered substrate specificity for L-glucose and inositol in scyllo-inositol dehydrogenase isolated from Paracoccus laeviglucosivorans.

scyllo-inositol dehydrogenase, isolated from Paracoccus laeviglucosivorans (Pl-sIDH), exhibits a broad substrate specificity: it oxidizes scyllo- and myo-inositols as well as L-glucose, converting L-glucose to L-glucono-1,5-lactone. Based on the crystal structures previously reported, Arg178 residue, located at the entry port of the catalytic site, seemed to be important for accepting substrates. Here, we report the role of Arg178 by using an alanine-substituted mutant for kinetic analysis as well as to determine the crystal structures. The wild-type Pl-sIDH exhibits the activity for scyllo-inositol most preferably followed by myo-inositol and L-glucose. On the contrary, the R178A mutant abolished the activities for both inositols, but remained active for L-glucose to the same extent as its wild-type. Based on the crystal structures of the mutant, the side chain of Asp191 flipped out of the substrate binding site. Therefore, Arg178 is important in positioning Asp191 correctly to exert its catalytic activities.Abbreviations: IDH: inositol dehydrogenase; LB: Luria-Bertani; kcat: catalyst rate constant; Km: Michaelis constant; NAD: nicotinamide dinucleotide; NADH: nicotinamide dinucleotide reduced form; PDB; Protein Data Bank; PDB entry: 6KTJ, 6KTK, 6KTL.

Externalized Mesentery Monitoring of Vascularized Jejunum Transfers.

PURPOSE: The use of externalized jejunal monitoring flaps for jejunum transfers could be facilitative for the direct clinical assessment. Although this monitoring method would seem to be highly reliable, we modified this method and used mesentery only as a monitor to make it easy to manage the monitor more. METHODS: Between 2013 and 2018, 43 patients underwent vascularized jejunum transfer for reconstruction of laryngopharyngectomy using the externalized mesentery monitor. There were 39 men and 4 women, and patient ages ranged from 40 to 80 years (average, 66.6 years). The nursing staff monitored the externalized mesentery by using handheld Doppler ultrasonography every 2 hours for 7 days after surgery. RESULTS: Three patients had rather weak signal of handheld Doppler ultrasonography on the externalized mesentery monitors during operation, and handheld Doppler ultrasonography could not be applied. Of the remaining 40 patients using the externalized mesentery monitor with handheld Doppler ultrasonography, 39 had an uncomplicated postoperative period. In 1 patient, no signal of Doppler ultrasonography and lack of bleeding by pin prick from the monitor segment were noted in the immediate postoperative period, and revision of the vascular anastomosis was performed. Finally, the graft was salvaged. There was no case of infection in the monitoring flap or hypertrophic scar at the resected part of the flap. CONCLUSIONS: Using the externalized mesentery monitoring flaps, clinical monitoring by examining the exteriorized monitoring flap is possible, and only mesentery monitors were managed easily compared with jejunum monitoring flaps.

Subcutaneous Allergic Sensitization to Protease Allergen Is Dependent on Mast Cells but Not IL-33: Distinct Mechanisms between Subcutaneous and Intranasal Routes.

Protease activity of papain, a plant-derived occupational allergen homologous to mite major allergens, is essential to IgE/IgG1 production and lung eosinophilia induced by intranasal papain administration in mice, and IL-33 contributes to these responses. In this work, we investigate skin and Ab responses induced by s.c. papain administration into ear lobes and responses induced by subsequent airway challenge with papain. Subcutaneous papain injection induced swelling associated with increased epidermal thickness, dermal inflammation, serum IgE/IgG1 responses, and Th2 cytokine production in draining lymph node cells restimulated in vitro. These responses were markedly less upon s.c. administration of protease inhibitor-treated papain. Results obtained by using mast cell-deficient mice and reconstitution of tissue mast cells suggested the contribution of mast cells to papain-specific IgE/IgG1 responses and eosinophil infiltration. The responses were equivalent between wild-type and IL-33(-/-) mice. After the subsequent airway challenge, the s.c. presensitized wild-type mice showed more severe lung eosinophilia than those without the presensitization. The presensitized IL-33(-/-) mice showed modest lung eosinophilia, which was absent without the presensitization, but its severity and IgE boost by the airway challenge were markedly less than the presensitized wild-type mice, in which protease activity of inhaled papain contributed to the responses. The results suggest that mechanisms for the protease-dependent sensitization differ between skin and airway and that cooperation of mast cell-dependent, IL-33-independent initial sensitization via skin and protease-induced, IL-33-mediated mechanism in re-exposure via airway to protease allergens maximizes the magnitude of the transition from skin inflammation to asthma in natural history of progression of allergic diseases.

ETS transcription factor ETV2 directly converts human fibroblasts into functional endothelial cells.

Transplantation of endothelial cells (ECs) is a promising therapeutic approach for ischemic disorders. In addition, the generation of ECs has become increasingly important for providing vascular plexus to regenerated organs, such as the liver. Although many attempts have been made to generate ECs from pluripotent stem cells and nonvascular cells, the minimum number of transcription factors that specialize in directly inducing vascular ECs remains undefined. Here, by screening 18 transcription factors that are important for both endothelial and hematopoietic development, we demonstrate that ets variant 2 (ETV2) alone directly converts primary human adult skin fibroblasts into functional vascular endothelial cells (ETVECs). In coordination with endogenous FOXC2 in fibroblasts, transduced ETV2 elicits expression of multiple key endothelial development factors, including FLI1, ERG, and TAL1, and induces expression of endothelial functional molecules, including EGFL7 and von Willebrand factor. Consequently, ETVECs exhibits EC characteristics in vitro and forms mature functional vasculature in Matrigel plugs transplanted in NOD SCID mice. Furthermore, ETVECs significantly improve blood flow recovery in a hind limb ischemic model using BALB/c-nu mice. Our study indicates that the creation of ETVECs provides further understanding of human EC development induced by ETV2.

Interaction between a Domain of the Negative Regulator of the Ras-ERK Pathway, SPRED1 Protein, and the GTPase-activating Protein-related Domain of Neurofibromin Is Implicated in Legius Syndrome and Neurofibromatosis Type 1.

Constitutional heterozygous loss-of-function mutations in the SPRED1 gene cause a phenotype known as Legius syndrome, which consists of symptoms of multiple café-au-lait macules, axillary freckling, learning disabilities, and macrocephaly. Legius syndrome resembles a mild neurofibromatosis type 1 (NF1) phenotype. It has been demonstrated that SPRED1 functions as a negative regulator of the Ras-ERK pathway and interacts with neurofibromin, the NF1 gene product. However, the molecular details of this interaction and the effects of the mutations identified in Legius syndrome and NF1 on this interaction have not yet been investigated. In this study, using a yeast two-hybrid system and an immunoprecipitation assay in HEK293 cells, we found that the SPRED1 EVH1 domain interacts with the N-terminal 16 amino acids and the C-terminal 20 amino acids of the GTPase-activating protein (GAP)-related domain (GRD) of neurofibromin, which form two crossing α-helix coils outside the GAP domain. These regions have been shown to be dispensable for GAP activity and are not present in p120(GAP). Several mutations in these N- and C-terminal regions of the GRD in NF1 patients and pathogenic missense mutations in the EVH1 domain of SPRED1 in Legius syndrome reduced the binding affinity between the EVH1 domain and the GRD. EVH1 domain mutations with reduced binding to the GRD also disrupted the ERK suppression activity of SPRED1. These data clearly demonstrate that SPRED1 inhibits the Ras-ERK pathway by recruiting neurofibromin to Ras through the EVH1-GRD interaction, and this study also provides molecular basis for the pathogenic mutations of NF1 and Legius syndrome.

Spred1, a Suppressor of the Ras-ERK Pathway, Negatively Regulates Expansion and Function of Group 2 Innate Lymphoid Cells.

Cytokines from group 2 innate lymphoid cells (ILC2s) have been implicated in acute allergic responses, such as papain-induced lung inflammation. However, the means of homeostatic regulation of ILC2s have not been established. In this study, we demonstrated that Spred1, a negative regulator of the Ras-ERK pathway, plays an important role in the proliferation and apoptosis of ILC2s and in cytokine secretion from ILC2s. Intranasal administration of papain stimulated IL-5 and IL-13 production in the lung, which was enhanced when Spred1 was deleted. In vitro, Spred1(-/-) ILC2s proliferated faster than wild type ILC2s did and produced higher levels of cytokines in response to IL-33. On the contrary, a MEK inhibitor suppressed ILC2 proliferation and cytokine production. Spred1 deficiency resulted in stabilization of GATA3, which has been shown to play essential roles in the maintenance and cytokine production of ILC2. These data suggest that Spred1 negatively regulates ILC2 development and functions through the suppression of the Ras-ERK pathway.

Presensitization to Ascaris antigens promotes induction of mite-specific IgE upon mite antigen inhalation in mice.

BACKGROUND: Patients with house dust mite (HDM) allergy or Ascariasis produce serum IgE specific to the antigens of HDM or nematode Ascaris, respectively. Although human IgE cross-reactivity has been reported between HDM and Ascaris antigens, it remains unclear whether it contributes to the pathogenesis of allergic diseases. We herein investigated the induction of cross-reactive antibodies and T cells in mice and effects of airway exposure to HDM antigens after preimmunization with Ascaris antigens. METHODS: Mice were intraperitoneally immunized with HDM or Ascaris antigens with Alum, followed by the intranasal administration of HDM antigens. Serum antigen-specific IgE and IgG were measured by ELISA. Cytokine release in splenocytes from Ascaris-immunized mice upon in vitro restimulation with HDM antigens were measured by ELISA. RESULTS: Immunization with Ascaris or HDM antigens induced cross-reactive IgG1. Splenocytes from Ascaris-immunized mice released IL-5 and IL-13 in response to the restimulation with HDM antigens. Subsequent airway exposure to HDM antigens promoted the induction of HDM-specific IgE and upregulation of HDM-specific IgG1 in Ascaris-immunized mice, whereas these responses were not detected or smaller without the Ascaris presensitization. CONCLUSIONS: We demonstrated that the immunization of naïve mice with Ascaris antigens induced production of antibodies and differentiation of Th2 cells, which were cross-reactive to HDM antigens, and accelerated induction of serum HDM-specific IgE upon subsequent airway exposure to HDM antigens in mice. These results suggest that sensitization to HDM towards IgE-mediated allergic diseases is faster in individuals with a previous history of Ascaris infection than in those without presensitization to Ascaris.

IL-33-mediated innate response and adaptive immune cells contribute to maximum responses of protease allergen-induced allergic airway inflammation.

How the innate and adaptive immune systems cooperate in the natural history of allergic diseases has been largely unknown. Plant-derived allergen, papain, and mite allergens, Der f 1 and Der p 1, belong to the same family of cysteine proteases. We examined the role of protease allergens in the induction of Ab production and airway inflammation after repeated intranasal administration without adjuvants and that in basophil/mast cell stimulation in vitro. Papain induced papain-specific IgE/IgG1 and lung eosinophilia. Der f 1 induced Der f 1-specific IgG1 and eosinophilia. Although papain-, Der f 1-, and Der p 1-stimulated basophils expressed allergy-inducing cytokines, including IL-4 in vitro, basophil-depleting Ab and mast cell deficiency did not suppress the papain-induced in vivo responses. Protease inhibitor-treated allergens and a catalytic site mutant did not induce the responses. These results indicate that protease activity is essential to Ab production and eosinophilia in vivo and basophil activation in vitro. IL-33-deficient mice lacked eosinophilia and had reduced papain-specific IgE/IgG1. Coadministration of OVA with papain induced OVA-specific IgE/IgG1, which was reduced in IL-33-deficient mice. We demonstrated IL-33 release, subsequent IL-33-dependent IL-5/IL-13 release, and activation of T1/ST2-expressing lineage(-)CD25(+)CD44(+) innate lymphoid cells in the lung after papain inhalation, suggesting the contribution of the IL-33-type 2 innate lymphoid cell-IL-5/IL-13 axis to the papain-induced airway eosinophilia. Rag2-deficient mice, which lack adaptive immune cells, showed significant, but less severe, eosinophilia. Collectively, these results suggest cooperation of adaptive immune cells and IL-33-responsive innate cells in protease-dependent allergic airway inflammation.

UPLC/ESI-MS/MS-based determination of metabolism of several new illicit drugs, ADB-FUBINACA, AB-FUBINACA, AB-PINACA, QUPIC, 5F-QUPIC and α-PVT, by human liver microsome.

The metabolism by human liver microsomes of several new illicit drugs, that is, N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3- carboxamide (ADB-FUBINACA), N-(1-amino-3-methyl-1-oxobutan-2-yl)-1- (4-fluorobenzyl)-1H-indazole-3-carboxamide (AB-FUBINACA), N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (AB-PINACA), quinolin-8-yl 1-pentyl-(1H-indole)-3-carboxylate (QUPIC), quinolin-8-yl 1-(5-fluoropentyl)-(1H-indole)-3-carboxylate (5 F-QUPIC) and α-pyrrolidinovalerothiophenone (α-PVT), which have indole, indazole, quinolinol ester and thiophene structures, was investigated using reversed-phase chromatography and mass spectrometry. The present method is based upon the oxidation by cytochrome p450 superfamily enzymes in the microsomes. The oxidation of ADB-FUBINACA and AB-FUBINACA mainly occurred on the N-(1-amino-alkyl-1-oxobutan) moiety. However, the oxidation of AB-PINACA seemed to occur on the 1-pentyl moiety. On the other hand, QUPIC and 5 F-QUPIC, which have a quinolinol ester structure, predominantly underwent a cleavage reaction to produce indoleacetic acid type metabolites. In contrast, the metabolism reaction of α-PVT was different from that of the other tested drugs, and various oxidation products were observed on the chromatograms. The obtained metabolites are not in conflict with the results predicted by MetaboLynx software. However, the exact structures of the metabolites, except for 1-pentyl-1H-indole-3-carboxylic acid (QUPIC metabolite) and 1-(5-fluoropentyl)-1H-indole-3-carboxylic acid (5 F-QUPIC metabolite), are currently not proven, because we have no authentic compounds for comparison. The proposed approach using human liver microsome seems to provide a new technology for the prediction of possible metabolites occuring in humans.

Coconut Atrium Causing Restrictive Physiology in the Right Ventricle.

We herein report a 61-year-old woman with a history of mitral valve replacement for rheumatic fever who presented with crural edema and ascites. Computed tomography showed massive left atrial (LA) calcification involving the interatrial septum, termed "coconut atrium." Catheterization revealed not only pulmonary artery hypertension but also a large V-wave in the pulmonary artery wedge pressure waveform and a dip-and-plateau pattern of right ventricular pressure. Three-dimensional transthoracic echocardiography confirmed the early attainment of peak LA volume and a decreased LA expansion index. Stiff LA syndrome due to coconut LA results in the development of restrictive right ventricular physiology.

Rhinoplasty for post-traumatic deviation of the nose with non-incisional external perforated osteotomy.

Osteotomy is often necessary for the repair of post-traumatic nasal bone deformities. Typically, tools such as chisels are used for osteotomies; however, we performed osteotomies using Kirschner wires without making a skin incision. Between April 2011 and July 2022, we performed rhinoplasty with external perforated osteotomy using Kirschner wires in 13 patients with post-traumatic nasal bone deformities (9 males and 4 females; mean age, 34 years, range 12-51 years), all of whom exhibited improvement, with only one case showing mild residual cosmetic deformity. None of the patients requested further revision, and all were satisfied with their functional results. The non-incisional external perforated technique is a reasonable method that allows for bone osteotomies along the fracture line and is well-controlled, predictable, and reproducible.

Utilization and Issues Related to Discharge Medication Summaries from Hospital Pharmacies to Community Pharmacies.

In 2020, the Japan Community Healthcare Organization (JCHO) Hoshigaoka Medical Center started providing information to community pharmacies about patients admitted to the acute care ward using discharge medication summaries (the summaries). We conducted an online self-recording survey of 149 pharmacies belonging to the Hirakata City Pharmacists Association to clarify the usability of the summaries, any related issues, and to further discuss future collaboration between hospitals and pharmacies. 46 pharmacies have received the summaries in the past, of which 44 pharmacies answered that they have utilized the summaries with patient instruction and prescription queries of doctors. However, two pharmacies responded they did not utilize the summaries, and the reasons were (a) the information was not timely and (b) patients whom the discharge medical summary was sent for did not come to the pharmacy. There were some requests regarding the summaries such as, "I would like to know what kind of information hospital pharmacists want from community pharmacists." Preference for sharing information other than the summaries (e.g., online tools) with hospital pharmacists was related to whether the pharmacy was providing home pharmaceutical visit services. The survey revealed that, in addition to the usability of the summaries, there are also events that prevent them from being utilized. Some of the challenges include the timing of sending the summaries, the accurate identification of the family pharmacy and the communication of follow-up after discharge from hospital. Collaborating with pharmacies providing home pharmaceutical visit services would be beneficial in creating new system of bidirectional information sharing.

Lipid polarity is maintained in absence of tight junctions.

The role of tight junctions (TJs) in the establishment and maintenance of lipid polarity in epithelial cells has long been a subject of controversy. We have addressed this issue using lysenin, a toxin derived from earthworms, and an influenza virus labeled with a fluorescent lipid, octadecylrhodamine B (R18). When epithelial cells are stained with lysenin, lysenin selectively binds to their apical membranes. Using an artificial liposome, we demonstrated that lysenin recognizes the membrane domains where sphingomyelins are clustered. Interestingly, lysenin selectively stained the apical membranes of epithelial cells depleted of zonula occludens proteins (ZO-deficient cells), which completely lack TJs. Furthermore, the fluorescent lipid inserted into the apical membrane by fusion with the influenza virus did not diffuse to the lateral membrane in ZO-deficient epithelial cells. This study revealed that sphingomyelin-cluster formation occurs only in the apical membrane and that lipid polarity is maintained even in the absence of TJs.

A novel derivatization reagent possessing a bromoquinolinium structure for biological carboxylic acids in HPLC-ESI-MS/MS.

A novel bromoquinolinium reagent, i.e. 1-(3-aminopropyl)-3-bromoquinolinium bromide (APBQ), was synthesized for the analysis of carboxylic acids. A simple and practical precolumn derivatization procedure using the APBQ in RP chromatography and MS (HPLC-MS) has been developed using bile acids and free fatty acids, as the representative carboxylic acids in biological samples. The APBQ efficiently reacted with carboxylic acids at 60°C for 60 min in the presence of N,N-dicyclohexylcarbodiimide and pyridine as the activation reagents. Because the APBQ possesses a bromine atom in the structure, the identification of a series of carboxylic acids was easily achieved due to the characteristic bromine isotope pattern in the mass spectra. The APBQ also has a quaternary amine structure, thus the positively charged derivatives are predominate for the highly sensitive detection of carboxylic acids. The APBQ was successfully applied to the selective determination of biological carboxylic acids in human plasma. The bile acids (chenodeoxycholic acid and deoxycholic acid) and several saturated (stearic acid and palmitic acid) and unsaturated free fatty acids (oleic acid and linoleic acid) were reasonably determined by HPLC-MS under the proposed procedure. Based on the results of analyses of human plasma and saliva, the proposed procedure using APBQ seems to be applicable for the qualitative and quantitative analyses of a series of carboxylic acids in biological samples.