A Case of Trigeminal Neuralgia in an Adult Patient With Lambdoid Synostosis.

Trigeminal neuralgia (TN) is characterized by sudden, brief intense pain in the distribution of the unilateral trigeminal nerve (TGN). Neurovascular compression (NVC) of the TGN is the most common cause of TN. Recent studies have suggested that a structural anomaly of the posterior cranial fossa might be involved in the development of TN, and several studies have documented the association between NVC-related TN and congenital posterior cranial deformities in adults. We present the case of a 56-year-old woman with NVC-related TN and unilateral lambdoid synostosis (ULS), along with a literature review, to investigate the relationship between TN and structural anomalies of the posterior fossa. This is the first report of TN in an adult with ULS. Mild and asymptomatic cases of lambdoid synostosis might have a higher incidence of NVC-related TN in association with posterior cranial fossa deformities.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study.

PURPOSE: Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits. METHODS: This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution. RESULTS: Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009). CONCLUSION: CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

pH-Sensitive Oscillatory Motion of a Urease Motor on the Urea Aqueous Phase.

A self-propelled object coupled with an enzyme reaction between urease and urea was investigated at the air/aqueous interface. A plastic object that was fixed to a urease-immobilized filter paper was used as a self-propelled object, termed a urease motor, placed on an aqueous urea solution. The driving force of the urease motor is the difference in the surface tension around the object. Oscillatory motion or no motion was triggered depending on the initial pH of the urea solution. Both the frequency and maximum speed of the oscillatory motion varied depending on the initial pH of the water phase. The mechanisms underlying the oscillatory motion and no motion were discussed in relation to the bell-shaped enzyme activity of urease in the enzyme reaction and the surface tension around the urease motor.

Cerebrospinal fluid drainage to prevent postoperative spinal cord injury in thoracic aortic repair.

BACKGROUND: Cerebrospinal fluid drainage (CSFD) is recommended as a spinal cord protective strategy in open and endovascular thoracic aortic repair. Although small studies support the use of CSFD, systematic reviews have not suggested definite conclusion and a large-scale study is needed. Therefore, we reviewed medical records of patients who had undergone descending and thoracoabdominal aortic repair (both open and endovascular repair) at multiple institutions to assess the association between CSFD and postoperative motor deficits. METHODS: Patients included in this study underwent descending or thoracoabdominal aortic repair between 2000 and 2013 at 12 hospitals belonging to the Japanese Association of Spinal Cord Protection in Aortic Surgery. We conducted a retrospective study to investigate whether motor-evoked potential monitoring is effective in reducing motor deficits in thoracic aortic aneurysm repair. We use the same dataset to examine whether CSFD reduces motor deficits after propensity score matching. RESULTS: We reviewed data from 1214 patients [open surgery, 601 (49.5%); endovascular repair, 613 (50.5%)]. CSFD was performed in 417 patients and not performed in the remaining 797 patients. Postoperative motor deficits were observed in 75 (6.2%) patients at discharge. After propensity score matching (n = 700), mixed-effects logistic regression performed revealed that CSFD is associated with postoperative motor deficits at discharge [adjusted odds ratio (OR), 3.87; 95% confidence interval (CI), 2.30-6.51]. CONCLUSION: CSFD may not be effective for postoperative motor deficits at discharge.

Mass Spectrometric Characterization of Histone H3 Isolated from in-Vitro Reconstituted and Acetylated Nucleosome Core Particle.

Post-translational modifications (PTMs) of histone N-terminal tails in nucleosome core particle (NCP), such as acetylation, play crucial roles in regulating gene expression. To unveil the regulation mechanism, atomic-level structural analysis of in-vitro modified NCP is effective with verifying the PTMs of histones. So far, identification of PTMs of NCP originating from living cells has mainly been performed using mass spectrometry (MS) techniques, such as bottom-up approach. The bottom-up approach is the most established method for protein characterization, but it does not always provide sufficient information on the acetylated sites of lysine residues in the histone tails if trypsin digestion is carried out. For histone proteins, which have many basic amino acids, trypsin generates too many short fragments that cannot be perfectly analyzed by tandem MS. In this study, we investigated the in vitro acetylation sites in the histone H3 tail using a top-down sequence analysis, matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) experiment, in combination with aminopeptidase digestion. Aminopeptidase can cleave peptide bonds one-by-one from the N-terminus of peptides or proteins, generating N-terminally truncated peptides and/or proteins. As a result, it was identified that this method enables sequence characterization of the entire region of the H3 tail. Also, application of this method to H3 in in-vitro acetylated NCP enabled assigning acetylation sites of H3. Thus, this method was found to be effective for obtaining information on in-vitro acetylation of NCP for structural biology study.

A practical guide for anesthetic management during intraoperative motor evoked potential monitoring.

Postoperative motor dysfunction can develop after spinal surgery, neurosurgery and aortic surgery, in which there is a risk of injury of motor pathway. In order to prevent such devastating complication, intraoperative monitoring of motor evoked potentials (MEP) has been conducted. However, to prevent postoperative motor dysfunction, proper understanding of MEP monitoring and proper anesthetic managements are required. Especially, a variety of anesthetics and neuromuscular blocking agent are known to attenuate MEP responses. In addition to the selection of anesthetic regime to record the baseline and control MEP, the measures to keep the level of hypnosis and muscular relaxation at constant are crucial to detect the changes of MEP responses after the surgical manipulation. Once the changes of MEP are observed based on the institutional alarm criteria, multidisciplinary team members should share the results of MEP monitoring and respond to check the status of monitoring and recover the possible motor nerve injury. Prevention of MEP-related adverse effects is also important to be considered. The Working Group of Japanese Society of Anesthesiologists (JSA) developed this practical guide aimed to help ensure safe and successful surgery through appropriate anesthetic management during intraoperative MEP monitoring.

Interfacial Dynamics in the Spontaneous Motion of an Aqueous Droplet.

Self-propelled droplets can spontaneously move using chemical energy. In several reports of self-propelled droplets, interfacial chemical reactions occur at the oil/aqueous interface to induce the Marangoni flow. While the dynamics of interfacial tension is essential to the droplet motion, there are few reports that quantitatively discuss the moving mechanism based on interfacial tension measurements. In this study, we focused on the self-propelled motion of an aqueous droplet in the oil phase, where the surfactant monoolein reacts with bromine at the interface, and estimated the physicochemical parameters related to the droplet motion based on the time series of interfacial tension. These results may reveal the general mechanism for the self-propelled motion of aqueous/oil droplets driven by the interfacial chemical reaction.

Association Between Motor-Evoked Potentials and Spinal Cord Damage Diagnosed With Magnetic Resonance Imaging After Thoracoabdominal and Descending Aortic Aneurysm Repair.

OBJECTIVES: The authors investigated the association between intraoperative motor-evoked potential (MEP) changes and the severity of spinal cord infarction diagnosed with magnetic resonance imaging (MRI) to clarify the discrepancy between them, which was observed in patients with postoperative motor deficits after thoracic and thoracoabdominal aortic surgery. DESIGN: A multicenter retrospective study. SETTING: Motor-evoked potential <25% of control values was deemed positive for spinal cord ischemia. The severity of spinal cord infarction was categorized into grades A to D based on previous studies using the most severe axial MRI slices. The associations between MRI grade, MEP changes, and motor deficits were examined using logistic regression. PARTICIPANTS: Twenty-three of 1,245 patients (from 1999 to 2013, at 12 hospitals in Japan) were extracted from medical records of patients who underwent thoracic and thoracoabdominal aortic repair, with intraoperative MEP examinations and postoperative spinal MRI. INTERVENTIONS: No intervention (observational study). MEASUREMENTS AND MAIN RESULTS: Motor-evoked potential <25% of control value was associated significantly with motor deficits at discharge (adjusted odds ratio [OR], 130.0; p = 0.041), but not with severity of spinal cord infarction (adjusted OR, 0.917; p = 0.931). Motor deficit at discharge was associated with severe spinal cord infarction (adjusted OR, 4.83; p = 0.043), MEP <25% (adjusted OR, 13.95; p = 0.031), and combined deficits (motor and sensory, motor and bowel or bladder, or sensory and bowel or bladder deficits; adjusted OR, 31.03; p = 0.072) in stepwise logistic regression analysis. CONCLUSION: Motor-evoked potential <25% was associated significantly with motor deficits at discharge, but not with the severity of spinal cord infarction.

Analysis of a lectin microarray identifies altered sialylation of mouse serum glycoproteins induced by whole-body radiation exposure.

Microarrays containing 45 different lectins were analyzed to identify global changes in the glycosylation of serum glycoproteins from mice exposed to whole-body γ-radiation. The results showed that radiation exposure increased and decreased the relative amounts of α-2,3- and α-2,6-sialic acids, respectively. The expression of α-2,3- and α-2,6-sialyltransferase genes in the liver was analyzed to determine whether changes in their expression were responsible for the sialic acid changes. The increase in α-2,3-sialic acid correlated with St3gal5 upregulation after radiation exposure; however, a decrease in St6gal1 expression was not observed. Analysis of a PCR array of genes expressed in irradiated mouse livers revealed that irradiation did not alter the expression of most of the included genes. These results suggest that glycomic screening of serum glycoproteins using lectin microarrays can be a powerful tool for identifying radiation-induced changes in the post-translational addition of sugar moieties to proteins. In addition, the results indicate that altered sialylation of glycoproteins may be an initial response to acute radiation exposure.

Graphite Furnace Atomic Absorption Spectrometric Evaluation of Iron Excretion in Mouse Urine Caused by Whole-Body Gamma Irradiation.

A procedure for the determination of iron in mice urine using graphite furnace atomic absorption spectrometry was developed. The mice urinary samples contain many organic compounds in the matrix, whose concentrations are approximately 20%, and the value is 30-fold higher compared to those found in human urine. Moreover, only 0.2 mL or less of urine was obtained as a sample volume per urination event. It was difficult to decompose the organic materials in the samples by wet digestion using mineral acids and oxidising agents, because of the tiny volumes. In this experiment, raw urinary samples were placed directly into the graphite tube furnace for analysis. The organic contents were simply ashed during the preheating stages. To facilitate ashing in the furnace, air was invaded from the surroundings by interrupting the stream of argon gas. Atomic absorption was measured at 248.3270 nm (wavelength for atomic absorption), with the background monitored at 247.0658 nm (wavelength for background correction). The optimised instrument operating conditions precluded the use of chemical modification technique. The analytical procedures used are quite simple, i.e. an aliquot of raw urine sample was injected directly into the graphite tube furnace and was followed by a suitable heating programme with no chemical modifier. Therefore, this method is useful for scientists who are not familiar with delicate chemical experiments. The proposed analytical method was applied as a kind of biomarker by determining iron concentrations in urinary samples of mice, which were irradiated with 4 Gy of gamma irradiation to their whole body. The time dependence of the iron concentration was determined, and the iron concentrations increased within 1 day of irradiation exposure, then decreased to ordinal values after several days.

3-Hydroxy-2-Nitrobenzoic Acid as a MALDI Matrix for In-Source Decay and Evaluation of the Isomers.

In in-source decay (ISD) in matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS), 1,5-diaminonaphthalene (1,5-DAN) is a most frequently used matrix probably due to the highly sensitive detection of fragment ions. 1,5-DAN is a reducing matrix generating c- and z-series ions by N-Cα bond cleavage. However, it is difficult for reducing matrices to distinguish leucine and isoleucine, and generate c(n-1)-series ions owing to proline (Pro) at residues n. Oxidizing matrices providing a- and x-series ions accompanied by d-series ions by Cα-C bond cleavage solve the problem, but their sensitivity of the ISD fragment ions has been lower than reducing matrices such as 1,5-DAN. Recently, 3-hydroxy-4-nitrobenzoic acid (3H4NBA) had been reported as an oxidizing matrix generating a-series ions with higher intensity compared with conventional oxidizing matrices such as 5-nitrosalicylic acid, but a little lower intensity compared with 1,5-DAN (Anal Chem 88, 8058-8063, 2016). In this study, 3H4NBA isomers (2H3NBA, 2H4NBA, 2H5NBA, 2H6NBA, 3H2NBA, 3H5NBA, 4H2NBA, 4H3NBA, 5H2NBA, and 3H4NBA) were evaluated. All the isomers generated a-series ions accompanied by d-series ions, wherein 3H2NBA, 3H5NBA, 4H2NBA, 4H3NBA, and 5H2NBA were first confirmed as oxidizing matrices for ISD. Among the isomers, 3H2NBA and 4H3NBA generated a-series ions with higher peak intensity compared with 3H4NBA for several peptides. Especially, 3H2NBA generated a-series ions with almost the same or higher intensity, and clearly higher peak resolution compared with c-series ions using 1,5-DAN in several cases. 3H2NBA was expected to contribute to ISD analyses in MALDI-MS as one of the most effective oxidizing matrices. Graphical Abstract ᅟ.

Phosphorylation of epidermal growth factor receptor at serine 1047 in cultured lung alveolar epithelial cells by bradykinin B2 receptor stimulation.

Accumulating evidence indicates that epidermal growth factor receptor (EGFR) is desensitized by phosphorylation of serine 1047 (Ser1047). We and other groups have reported that stimulation of a receptor of tumor-necrosis factor α (TNFα) and Toll-like receptor 5 (TLR5) induced the phosphorylation of Ser1047 through activation of p38 mitogen-activated protein kinase (p38 MAPK) in cultured lung alveolar epithelial A549 cells. However, phosphorylation of EGFR at Ser1047 by stimulation of any G-protein coupled receptors (GPCRs) has not been reported in any cultured cells. In the present study, we first confirmed that A549 cells expressed bradykinin (BK) B2 receptor, and then, we examined whether BK treatment of A549 cells activated MAPKs and induced the phosphorylation of EGFR at Ser1047. Immunoblotting analysis and reporter gene assays indicated that BK activated the pathways of extracellular signal-regulated kinase (ERK) and p38 MAPK. Inhibitor studies suggested that Gq/11 was mainly involved in the activation of ERK and p38 MAPK. We found that stimulation of the BK B2 receptor, but not the BK B1 receptor, induced phosphorylation of EGFR at Ser1047. Pharmacological experiments indicated that both ERK and p38 MAPK were involved in the phosphorylation of EGFR. These results strongly suggested that BK regulates EGFR functions in lung alveolar epithelial cells. In addition, we found that BK treatment increased the mRNA level of dual specificity MAPK phosphatase 5 (DUSP5) in an ERK-dependent manner, which suggested that a negative feedback mechanism of ERK existed in the cells.

Clinical Utility of Intraoperative Motor-Evoked Potential Monitoring to Prevent Postoperative Spinal Cord Injury in Thoracic and Thoracoabdominal Aneurysm Repair: An Audit of the Japanese Association of Spinal Cord Protection in Aortic Surgery Database.

BACKGROUND: Spinal cord ischemic injury is the most devastating sequela of descending and thoracoabdominal aortic surgery. Motor-evoked potentials (MEPs) have been used to intraoperatively assess motor tract function, but it remains unclear whether MEP monitoring can decrease the incidence of postoperative motor deficits. Therefore, we reviewed multicenter medical records of patients who had undergone descending and thoracoabdominal aortic repair (both open surgery and endovascular repair) to assess the association of MEP monitoring with postoperative motor deficits. METHODS: Patients included in the study underwent descending or thoracoabdominal aortic repair at 12 hospitals belonging to the Japanese Association of Spinal Cord Protection in Aortic Surgery between 2000 and 2013. Using multivariable mixed-effects logistic regression analysis, we investigated whether intraoperative MEP monitoring was associated with postoperative motor deficits at discharge after open and endovascular aortic repair. RESULTS: We reviewed data from 1214 patients (open surgery, 601 [49.5%]; endovascular repair, 613 [50.5%]). MEP monitoring was performed in 631 patients and not performed in the remaining 583 patients. Postoperative motor deficits were observed in 75 (6.2%) patients at discharge. Multivariable logistic regression analysis revealed that postoperative motor deficits at discharge did not have a significant association with MEP monitoring (adjusted odds ratio [OR], 1.13; 95% confidence interval [CI], 0.69-1.88; P = .624), but with other factors: history of neural deficits (adjusted OR, 6.08; 95% CI, 3.10-11.91; P < .001), spinal drainage (adjusted OR, 2.14; 95% CI, 1.32-3.47; P = .002), and endovascular procedure (adjusted OR, 0.45; 95% CI, 0.27-0.76; P = .003). The sensitivity and specificity of MEP <25% of control value for motor deficits at discharge were 37.8% (95% CI, 26.5%-49.5%) and 95.5% (95% CI, 94.7%-96.4%), respectively. CONCLUSIONS: MEP monitoring was not significantly associated with motor deficits at discharge.

Metabolomic screening using ESI-FT MS identifies potential radiation-responsive molecules in mouse urine.

The demand for establishment of high-throughput biodosimetric methods is increasing. Our aim in this study was to identify low-molecular-weight urinary radiation-responsive molecules using electrospray ionization Fourier transform mass spectrometry (ESI-FT MS), and our final goal was to develop a sensitive biodosimetry technique that can be applied in the early triage of a radiation emergency medical system. We identified nine metabolites by statistical comparison of mouse urine before and 8 h after irradiation. Time-course analysis showed that, of these metabolites, thymidine and either thymine or imidazoleacetic acid were significantly increased dose-dependently 8 h after radiation exposure; these molecules have already been reported as potential radiation biomarkers. Phenyl glucuronide was significantly decreased 8 h after radiation exposure, irrespective of the dose. Histamine and 1-methylhistamine were newly identified by MS/MS and showed significant, dose-dependent increases 72 h after irradiation. Quantification of 1-methylhistamine by enzyme-linked immunosorbent assay (ELISA) analysis also showed a significant increase 72 h after 4 Gy irradiation. These results suggest that urinary metabolomics screening using ESI-FT MS can be a powerful tool for identifying promising radiation-responsive molecules, and that urinary 1-methylhistamine is a potential radiation-responsive molecule for acute, high-dose exposure.

Periodic Oscillatory Motion of a Self-Propelled Motor Driven by Decomposition of H2 O2 by Catalase.

A self-propelled motor driven by the enzymatic reaction of catalase adsorbed onto a filter paper floating on an aqueous solution of H2 O2 was used to study nonlinear behavior in the motor's motion. An increase in the concentration of H2 O2 resulted in a change from no motion to irregular oscillatory motion, periodic oscillatory motion, and continuous motion. The mechanisms underlying oscillation and mode bifurcation are discussed based on experimental results on O2 bubble formation and growth on the underside of the motor.

The Flux of Euglena gracilis Cells Depends on the Gradient of Light Intensity.

We have quantified the photomovement behavior of a suspension of Euglena gracilis representing a behavioral response to a light gradient. Despite recent measurements of phototaxis and photophobicity, the details of macroscopic behavior of cell photomovements under conditions of light intensity gradients, which are critical to understand recent experiments on spatially localized bioconvection patterns, have not been fully understood. In this paper, the flux of cell number density under a light intensity gradient was measured by the following two experiments. In the first experiment, a capillary containing the cell suspension was illuminated with different light intensities in two regions. In the steady state, the differences of the cell numbers in the two regions normalized by the total number were proportional to the light difference, where the light intensity difference ranged from 0.5-2.0 µmol m-2 s-1. The proportional coefficient was positive (i.e., the bright region contained many microorganisms) when the mean light intensity was weak (1.25 µmol m-2 s-1), whereas it was negative when the mean intensity was strong (13.75 µmol m-2 s-1). In the second experiment, a shallow rectangular container of the suspension was illuminated with stepwise light intensities. The cell number density distribution exhibited a single peak at the position where the light intensity was about Ic ≃ 3.8 µmol m-2 s-1. These results suggest that the suspension of E. gracilis responded to the light gradient and that the favorable light intensity was Ic.

3-Hydroxy-4-nitrobenzoic Acid as a MALDI Matrix for In-Source Decay.

In-source decay (ISD) in matrix-assisted laser desorption/ionization (MALDI) is a rapid sequencing method for peptides. 1,5-Diaminonaphthalene (1,5-DAN) is a most frequently used matrix for ISD. However, using 1,5-DAN generates mainly c- and z-series ions by N-Cα bond cleavage, which makes it difficult to distinguish leucine (Leu) and isoleucine (Ile), and frequently lacks c(n-1)-series ions owing to proline (Pro) at residues n. Several oxidizing matrices generating a- and x-series ions accompanied by d-series ions by Cα-C bond cleavage have been reported, but an issue remained concerning their sensitivity. 3-Hydroxy-4-nitrobenzoic acid (3H4NBA) has been reported as a matrix for 2-nitrobenzenesulfenyl-labeled peptides by Matsuo et al. (Proteomics 2006, 6, 2042-2049). Here, we used 3H4NBA as an oxidizing matrix for ISD. As a result, numerous a- and d-series ions for amyloid ß 1-40 were generated with high sensitivity using 3H4NBA. Each of the two Leu and two Ile was identified by the d-series ions. The sensitivity of the a-series ions using 3H4NBA was a little lower than that of c-series ions using 1,5-DAN. The same tendency was observed for N-acetyl renin substrate and ACTH 18-39. The a-series ions were detected, even at the left side of Pro. The sensitivity of the a-series ions using 3H4NBA was higher than with other existing oxidizing matrices, such as 5-nitrosalicylic acid and 5-formyl salycilic acid. The ions were detected over the entire area of the matrix-analyte spot using 3H4NBA. 3H4NBA was confirmed to be a useful oxidizing matrix for ISD, leading to higher sequence coverage of peptides.

Nitration is exclusive to defense-related PR-1, PR-3 and PR-5 proteins in tobacco leaves.

Protein tyrosine nitration is an important post-translational modification. A variety of nitrated proteins are reported in Arabidopsis leaves and seedlings, sunflower hypocotyls, and pea roots. The identities of nitrated proteins are species-/organ-specific, and chloroplast proteins are most nitratable in leaves. However, precise mechanism is unclear. Here, we investigated nitroproteome in tobacco leaves following exposure to nitrogen dioxide. Proteins were extracted, electrophoresed and immunoblotted using an anti-3-nitrotyrosine antibody. Mass spectrometry and FASTA search identified for the first time an exclusive nitration of pathogenesis-related proteins, PR-1, PR-3 and PR-5, which are reportedly located in the apoplast or the vacuole. Furthermore, Tyr(36) of thaumatin-like protein E2 was identfied as a nitration site. The underlying mechanism and physiological relevance are discussed.

Hepcidin-2 in mouse urine as a candidate radiation-responsive molecule.

We used high-performance liquid chromatography to separate urine obtained from whole-body gamma-irradiated mice (4 Gy) before analyzing each fraction with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry to identify radiation-responsive molecules. We identified two candidates: hepcidin antimicrobial peptide 2 (hepcidin-2) and peptide fragments of kidney androgen-regulated protein (KAP). We observed that peak increases of hepcidin-2 in urine were delayed in a dose-dependent manner (1 Gy and above); however, the amount of KAP peptide fragments showed no correlation with radiation dose. In addition, an increase in hepcidin-2 after exposure to relatively low radiation doses (0.25 and 0.5 Gy, respectively) was biphasic (at 8-48 h and 120-168 h, respectively, after irradiation). The increase in hepcidin-2 paralleled an increase in hepcidin-2 gene (Hamp2) mRNA levels in the liver. These results suggest that radiation exposure directly or indirectly induces urinary excretion of hepcidin-2 at least in part by the upregulation of Hamp2 mRNA in the liver.

Membrane Protein Analyses Using Alkylated Trihydroxyacetophenone (ATHAP) as a MALDI Matrix.

Membrane proteins containing hydrophobic regions have been difficult to analyze using MALDI-MS, probably due to the use of conventional matrices with a low affinity for hydrophobic peptides. Recently, we reported 1-(2,4,6-trihydroxyphenyl)octan-1-one (alkylated trihydroxyacetophenone (ATHAP)) as a matrix for hydrophobic peptides. In this study, ATHAP was applied to analyze membrane proteins containing transmembrane domains. As a result, we detected intact molecular ions for bacteriorhodopsin (BR) containing seven transmembrane domains that are difficult to detect using 2,4,6-trihydroxyacetophenone or sinapinic acid, by using ATHAP. In addition, we detected digest ions containing all seven transmembrane domains that are difficult to detect using α-cyano-4-hydroxycinnamic acid (CHCA), by using ATHAP. Moreover, ions for hydrophobic digests containing a single transmembrane domain for cadherin 1 (CDH1), fibroblast growth factor receptor 4 (FGFR4), epithelial cell adhesion molecule (EPCAM) recombinant proteins, and human epidermal growth factor receptor type 2 (HER2) were detected with higher sensitivity using ATHAP than with CHCA, confirming that ATHAP improved the membrane protein analyses, especially for hydrophobic regions such as transmembrane domains.