Extreme ultraviolet time-resolved photoelectron spectroscopy of adenine, adenosine and adenosine monophosphate in a liquid flat jet.

Time-resolved photoelectron spectroscopy using an extreme-ultraviolet (XUV) probe pulse was used to investigate the UV photoinduced dynamics of adenine (Ade), adenosine (Ado), and adenosine-5-monophosphate (AMP) in a liquid water jet. In contrast to previous studies using UV probe pulses, the XUV pulse at 21.7 eV can photoionize all excited states of a molecule, allowing for full relaxation pathways to be addressed after excitation at 4.66 eV. This work was carried out using a gas-dynamic flat liquid jet, resulting in considerably enhanced signal compared to a cylindrical jet. All three species decay on multiple time scales that are assigned based on their decay associated spectra; the fastest decay of ∼100 fs is assigned to ππ* decay to the ground state, while a smaller component with a lifetime of ∼500 fs is attributed to the nπ* state. An additional slower channel in Ade is assigned to the 7H Ade conformer, as seen previously. This work demonstrates the capability of XUV-TRPES to disentangle non-adiabatic dynamics in an aqueous solution in a state-specific manner and represents the first identification of the nπ* state in the relaxation dynamics of adenine and its derivatives.

Two patients with α-chain hemoglobin variant Hb Q-Iran detected by measuring hemoglobin A1c using the variant mode of the HA-8180V HPLC analyzer.

Hemoglobin variants are often discovered when hemoglobin A1c (HbA1c) levels measured with a high-performance liquid chromatography (HPLC) system in fast mode are found to be low. The HA-8180V HPLC analyzer by Arkray offers two measurement modes: fast mode (FM) and variant mode (VM). Two Japanese patients with α-chain variant Hb Q-Iran detected incidentally after analyses with the HA-8180V in VM showed an abnormal peak, are presented. The first patient was a man in his 70 s, and the second patient was a man in his 50 s. Both were non-diabetic, but their results from HbA1c measurement in VM showed an abnormal peak. The VM-HbA1c, FM-HbA1c, and HbA1c measured by enzymatic assay and glycated albumin levels of the two patients were all within the reference ranges. They were diagnosed as having Hb Q-Iran (α2-75Asp → His) by globin gene analysis. It is difficult to detect α-chain hemoglobin variants based on abnormal FM-HbA1c levels, but measuring HbA1c in VM is useful for efficiently detecting hemoglobin variants.

Time-resolved photoelectron spectroscopy of iodide-4-thiouracil cluster: The ππ* state as a doorway for electron attachment.

The photophysics of thiobases-nucleobases in which one or more oxygen atoms are replaced with sulfur atoms- vary greatly depending on the location of sulfonation. Not only are direct dynamics of a neutral thiobase impacted, but also the dynamics of excess electron accommodation. In this work, time-resolved photoelectron spectroscopy is used to measure binary anionic clusters of iodide and 4-thiouracil, I- · 4TU. We investigate charge transfer dynamics driven by excitation at 3.88 eV, corresponding to the lowest ππ* transition of the thiouracil, and at 4.16 eV, near the cluster vertical detachment energy. The photoexcited state dynamics are probed by photodetachment with 1.55 and 3.14 eV pulses. Excitation at 3.88 eV leads to a signal from a valence-bound ion only, indicating a charge accommodation mechanism that does not involve a dipole-bound anion as an intermediate. Excitation at 4.16 eV rapidly gives rise to dipole-bound and valence-bound ion signals, with a second rise in the valence-bound signal corresponding to the decay of the dipole-bound signal. The dynamics associated with the low energy ππ* excitation of 4-thiouracil provide a clear experimental proof for the importance of localized excitation and electron backfilling in halide-nucleobase clusters.

Analysis of five cases showing false-high Hemoglobin A1c due to reduced catalase activity.

We encountered five cases that exhibited false-high Hemoglobin A1c (HbA1c) levels when samples were examined using the enzyme-based NORUDIA N HbA1c kit. HbA1c levels were higher than those obtained using other methods, such as HPLC, immune-based methods, and other enzyme-based kits. This kit produced inaccurate results for HbA1c when residual peroxides were present in samples. The addition of peroxidase solution restored false-high HbA1c levels in the five cases, indicating that reduced catalase activity was responsible for these values because catalase eliminates peroxide. Catalase activity and gene mutations were examined in the five cases and an immunohistological analysis was performed to assess the expression of catalase. Cases #1 and 2 were diagnosed as acatalasemia and cases #3, 4, and 5 as hypocatalasemia based on compound heterozygous SNP and heterozygous splicing mutations in the catalase gene. Therefore, impaired catalase activity was responsible for false-high HbA1c levels measured by the NORUDIA N HbA1c kit.

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Case 1 presented with severe anemia and received an intrauterine blood cell transfusion at 33 weeks of gestation. The anemia spontaneously improved in early infancy. Case 2, the father of Case 1, had an uneventful birth with no evidence of anemia, though microcytic anemia was observed during childhood. The genetic analysis of the ß-globin gene cluster identified a novel heterozygous deletion of DNA extending from the Gγ-globin gene downstream to the ß-globin gene, confirming a diagnosis of (G γA γδß)0 -thalassemia. In cases where thalassemia is suspected based on blood tests, a genetic diagnosis should be performed for the sake of the offspring.

Establishment of a reference interval for glycated albumin based on medical check-up data from multiple medical institutions.

Objectives: Data were collected to establish a reference interval for glycated albumin (GA), as well as to calculate a cutoff value for diagnosing diabetes mellitus and the GA level corresponding to a 75-g oral glucose tolerance test (OGTT) 2 h plasma glucose (2h-PG) level of 200 mg/dL.Methods: This study involved 1,843 subjects who were undergoing medical check-ups at several medical institutions and whose HbA1c and GA levels had been measured by OGTT.Results: The GA reference interval that was calculated based on the data obtained from study subjects with normal glucose tolerance was 12.1-17.1%. Using standardized major axis regression, the levels that corresponded to an OGTT 2h-PG level of 11.1 mmol/L were a GA level of 17.5% and an HbA1c level of 47.5 mmol/mol. A receiver-operating characteristic curve analysis was used to calculate the points at which sensitivity and specificity matched as the cutoff values, and the results yielded a GA level of 15.0% (sensitivity 69.3%).Conclusions: The GA reference interval was calculated to be 12.1-17.1%. We propose a GA level of 17.4% as a cutoff value to diagnose diabetes mellitus and a GA level of 15.0% as a screening cutoff value for diabetes mellitus, taking previous reports into account.

Estimation of mean erythrocyte age using HbA1c or HbA1c/glycated albumin for evaluation of anemia severity.

BACKGROUND: Hemoglobin A1c (HbA1c) levels are low in patients with hemolytic anemia, as HbA1c reflects mean erythrocyte age (MRBC ). Erythrocyte creatine (EC) is a hemolytic indicator that also reflects MRBC . We previously reported an equation for estimating MRBC using EC (EC-MRBC ). AIMS: In this study, EC-MRBC was compared to the HbA1c level expressed in the International Federation of Clinical Chemistry and Laboratory Medicine units (iA1c) and to the iA1c/glycated albumin (GA) ratio to estimate MRBC . METHODS: This study included 238 subjects, including patients with hemolytic anemia and/or type 2 diabetes mellitus (T2DM). RESULTS: In non-diabetic individuals, both iA1c and iA1c/GA showed a strong positive correlation with EC-MRBC (p < 0.0001). The equations to estimate iA1c-MRBC and iA1c/GA-MRBC derived from the regression equations between EC-MRBC and iA1c, and EC-MRBC and iA1c/GA in nondiabetic individuals were 1.45 × iA1c and 20.0 × iA1c/GA, respectively. iA1c-MRBC and iA1c/GA-MRBC in non-diabetic individuals without hemolytic anemia were 57.6 ± 4.0 and 57.1 ± 6.4 days, respectively, and iA1c/GA-MRBC in T2DM patients without hemolytic anemia was 56.0 ± 8.8 days.; no significant difference was seen in the comparisons. CONCLUSIONS: The MRBC can be estimated using iA1c or iA1c/GA in non-diabetic individuals, and iA1c/GA in T2DM patients.

Usefulness of measuring fast valley height rate using high-performance liquid chromatography for variant hemoglobin, Hb A2-Niigata.

We have reported cases of hemoglobin (Hb) A2-Niigata (δ1Val → Ala) with δ chain variant Hb and falsely high HbA1c levels. In subjects with Hb A2-Niigata, shoulder-shaped anomalous peak was detected immediately before the HbA1c peaks using high-performance liquid chromatography (HPLC; HLC-723 G9). The phenomenon where the valley between peaks of LA1c+ , a fraction containing labile HbA1c, and HbA1c fraction [fast valley (FV)] became shallow owing to the anomalous peak was observed. In this study, we attempted to quantify the height index of the FV. We assumed that the index FV height rate (FVHR) was useful for screening Hb A2-Niigata. Five subjects with Hb A2-Niigata were compared with the control group of 50 subjects without diabetes and 50 with diabetes. Various indices were measured using HPLC chromatograms, and FVHR was calculated based on these indices. FVHR in subjects with Hb A2-Niigata was significantly higher than that in subjects without and with diabetes (all P < 0.001). Furthermore, when the cutoff value of FVHR was set at 23-30%, Hb A2-Niigata could be diagnosed with high sensitivity and specificity (both 100%). Hb A2-Niigata can be screened using FVHR with high sensitivity and specificity. FVHR might be also useful for screening other variant hemoglobins with abnormal HPLC chromatograph.

Usefulness of HbA1c Measurements by HPLC- and Immuno-Assay for Screening Unstable Hemoglobinopathy.

OBJECTIVE: Unstable hemoglobinopathy (UH), red blood cell membrane disease (MD), and red blood cell enzymopathy are known as major congenital hemolytic anemias. Specialized examinations are needed for their differential diagnosis. We hypothesized that simultaneous measurements of HbA1c levels using high-performance liquid chromatography (HPLC) by fast mode (FM) and immunoassay [HPLC (FM)-HbA1c and IA-HbA1c, respectively] are useful for the differential diagnosis of UH from other congenital hemolytic anemias and verified this hypothesis in this study. METHODS: HPLC (FM)-HbA1c and IA-HbA1c levels were simultaneously measured in 5 variant hemoglobinopathy (VH) patients with ß-chain heterozygous mutation, 8 MD patients, 6 UH patients, and 10 healthy controls. None of the patients had diabetes mellitus. RESULTS: In VH patients, HPLC-HbA1c levels were low, whereas IA-HbA1c levels were within the reference range. In MD patients, HPLC-HbA1c and IA-HbA1c levels were similarly low. In UH patients, both HPLC-HbA1c and IA-HbA1c levels were low, but HPLC-HbA1c levels were significantly lower than IA-HbA1c levels. The HPLC-HbA1c/IA-HbA1c ratio was 90% or more in all MD patients and control subjects. This ratio was, however, less than 90% in all VH patients and UH patients. CONCLUSION: The HPLC (FM)-HbA1c/IA-HbA1c ratio calculated using simultaneous measurements of HPLC (FM)-HbA1c and IA-HbA1c levels is useful for the differential diagnosis of VH, MD, and UH.

A case of a novel hemoglobin variant, Hb A2-Karatsu, discovered following a falsely elevated HbA1c value.

The patient, a man in his thirties, presented to our hospital for a secondary examination after a 2020 medical check-up found a high hemoglobin A1c (HbA1c) level on high-performance liquid chromatography (HPLC). The HbA1c level determined by HPLC (HA-8180V, fast mode) was elevated at 6.8%, but a 75-g glucose tolerance test showed normal glucose tolerance. The glycated albumin level was within the reference range at 14.6%. The continuous glucose monitoring-derived mean blood glucose and the percentage of time in range were 99 mg/dL and 98%, respectively. The HbA1c levels determined by HPLC (G9, fast mode), enzymatic assay, and immunoassay were all 5.3%. An isoelectric focusing analysis showed an abnormal band on the anode side of HbA2, and a globin gene analysis detected a heterozygous mutation at codon 144 [AAG (Lys) → TAG (stop codon)] in the δ-chain. Since this mutation is a novel δ-chain hemoglobin variant, it was given the name 'Hb A2-Karatsu'.

Direct Detection of Long-Range Interdomain Auger Recombination in Dumbbell-Shaped Quasi-Type-II Nanoparticle.

Multicarrier dynamics in heterostructured ZnS-AgInS2 (ZAIS) dumbbell-like nanoparticle (nanodumbell), which consists of two visible-light absorptive domains (ellipsoidal tip domains) directly linked to each end of a 22 nm length rod domain of the ZAIS nanodumbell with a quasi-type-II heterostructure, was investigated by femtosecond transient absorption spectroscopy under variable excitation intensities. Quantitative analysis together with the numerical simulations for the excitation intensity dependence of the dynamics revealed that only one electron-hole pair survived in the overall dumbbell as a consequence of Auger recombination, even though multiple carriers were formed on both terminal tip domains. This result strongly suggested carrier-carrier interaction between the tip domains, leading to the long-range Auger recombination via tunneling across a rod potential barrier.

Electron attachment dynamics following UV excitation of iodide-2-thiouracil complexes.

The dynamics of low energy electron attachment to the thio-substituted uracil analog 2-thiouracil are investigated using time-resolved photoelectron spectroscopy (TRPES) of iodide-2-thiouracil (I-·2TU) binary clusters. In these experiments, the anions are excited at pump energies of 4.16 and 4.73 eV, and the ensuing dynamics are probed by photodetachment at 1.59 and 3.18 eV. Upon excitation near the vertical detachment energy (4.16 eV), dipole bound (DB) and valence bound (VB) anion signals appear almost instantaneously, and the DB state of the 2TU anion undergoes an ultrafast decay (∼50 fs). At 4.73 eV, there is no evidence for a DB state, but features attributed to two VB states are seen. The transient negative ions formed by photoexcitation decay by autodetachment and I- fragmentation. The I- dissociation rates and their dependence on excitation energy agree reasonably well with the Rice-Ramsperger-Kassel-Marcus calculations. Notable differences with respect to TRPES of the related iodide-uracil anion are observed and discussed.

Measurement of erythrocyte creatine might be useful for diagnosing latent hemolysis.

OBJECTIVES: Whereas HbA1c values are low relative to glycemia in patients with hemolytic anemia, including compensatory anemia, low HbA1c levels along with negative results for conventional hemolysis indicators have been reported in patients with latent hemolysis. Conversely, glycated albumin (GA) is a glycemic control indicator unaffected by hemolysis. Erythrocyte creatine (EC) is a hemolysis indicator that reflects the mean age of red blood cells (MRBC). We recently reported a formula for obtaining MRBC based on EC. The present study examined the usefulness of EC measurements and MRBC calculated with EC for diagnosing latent hemolysis. MATERIALS AND METHODS: Two patients with latent hemolysis and low HbA1c values relative to glycemia were investigated, while controls comprised 214 patients (including patients with hemolysis and/or type 2 diabetes mellitus). HbA1c was expressed in International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) units (iA1c). GA/iA1c ratios, reticulocyte counts, EC, and MRBC in patients with latent hemolysis were compared to non-hemolysis, compensatory hemolysis, and hemolytic anemia patients. RESULTS: Both reticulocyte counts and haptoglobin levels were within reference ranges in patients with latent hemolysis. GA/iA1c ratios and EC were higher than reference values in patients with latent hemolysis, and MRBC values were 41.6 and 48.4 days, respectively, shorter than the reference range (49.1-66.8 days). CONCLUSIONS: EC measurement and MRBC values calculated on the basis of EC might be useful for diagnosing latent hemolysis.

Femtosecond dynamics of stepwise two-photon ionization in solutions as revealed by pump-repump-probe detection with a burst mode of photoexcitation.

Pump-repump-probe spectroscopy with a burst mode of photoexcitation was applied to the direct observation of the photoionization dynamics of perylene in the solution phase. Irradiation of a pump pulse train generated with birefringent crystals effectively accumulated an intermediate S1 state and a repump pulse triggered photoionization in the higher excited state, ensuring sufficiently large signal intensity to probe. Two-photon excitation to the energy level, which is 0.7 eV lower than the ionization potential in the gas phase, results in instantaneous formation of the radical cation of perylene in acetonitrile, unlike aromatic amines in previous reports. In addition, subsequent recombination dynamics between the radical cation and ejected electron was monitored in polar and nonpolar solvents. The ultrafast recombination in nonpolar solvents suggests that the distribution of the distance in the cation-ejected electron pair largely evolves even in acetonitrile in the femtosecond timescale, in which the solvation is not completed and the dielectric constant is still low. The recombination process in acetonitrile was well reproduced with simulations based on the Smoluchowski equation taking account of the transient change in the dielectric constant by solvation.

Glycated albumin (GA) and the GA/HbA1c ratio are higher in diabetic patients positive for insulin antibodies with high binding capacity and low affinity.

Patients with diabetes mellitus having insulin antibodies (InsAb) with properties of high binding capacity and low affinity, which are observed in insulin autoimmune syndrome (IAS), are known to have greater plasma glucose fluctuations. Glycated albumin (GA) and the GA/HbA1c ratio have been demonstrated to reflect plasma glucose fluctuations. Hence, we hypothesized that GA or the GA/HbA1c ratio in diabetic patients having InsAb with properties of high binding capacity and low affinity may be higher than those in InsAb-negative diabetic patients, and we verified this hypothesis. Subjects were 12 diabetic patients who had InsAb noted while being treated with insulin and were subjected to Scatchard analysis and whose InsAb had properties similar to those of patients with IAS (affinity constant K1 < 0.24 × 1/10-8 M, number of binding sites R1 ≥ 11.5 × 10-8 M) [four cases of type 1 diabetes (T1D) and eight cases of type 2 diabetes (T2D)]. The control group consisted of T1D and T2D cases matched to the T1D and T2D cases, respectively, according to sex, age, BMI, and HbA1c. GA and the GA/HbA1c ratio were compared between both groups. GA and the GA/HbA1c ratio in InsAb-positive patients was significantly higher than that in the control group for both T1D and T2D patients. Diabetic patients having InsAb with properties of high binding capacity and low affinity had higher GA and the GA/HbA1c ratio than those of InsAb-negative patients. Greater plasma glucose fluctuations were suggested in InsAb-positive diabetic patients.

A case of α-chain variant hemoglobin (Hb Chad) with falsely high HbA1c levels measured by immunoassay.

Variant hemoglobin is often detected during the diagnosis and treatment of diabetes mellitus. We here describe a case of α2-chain variant hemoglobin (Hb Chad) that was identified as a result of differences in HbA1cs values determined by different assays. HbA1c measured by immunoassay was thus falsely high, whereas that measured by high-performance liquid chromatography (HPLC) was slightly low. Sequencing analysis revealed a heterozygous GAG (glutamic acid) → AAG (lysine) mutation at amino acid position 23 of the α2-globin gene. This residue is located at the surface of the α-chain in the crystal structure of hemoglobin. The high HbA1c value determined by immunoassay might have been the result of increased antigenicity of the variant hemoglobin, whereas the low value measured by HPLC reflected differential fractionation of the variant relative to the wild-type protein. Hb Chad has been reported in only three cases to date, and HbA1c was measured for the first time. This is the first case where falsely high HbA1c measured by immunoassay due to increased antigenicity in α-chain variant hemoglobin. This case highlights the importance of comparison with other parameters related to plasma glucose such as glycated albumin if an HbA1c abnormality is suspected. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13340-021-00529-y.

Direct determination of molar absorption coefficients of several molecules in the lowest excited singlet states.

Molar absorption coefficient of the lowest excited state is an indispensable information for the quantitative investigation of photochemical reactions by means of transient absorption spectroscopy. In the present work, we quantitatively estimated the molar absorption coefficients of the S1 state of the solute in three solution systems, Rhodamine B in ethanol, ZnTPP in DMF and N,N'-bis(2,6-diisopropylphenyl)terrylene-3,4,11,12-tetracarboxydiimide (TDI) in chloroform, by perfectly bleaching the ground state molecules using the picosecond 532-nm laser pulse with a large number of photons. These solution systems were selected because no obvious photodegradation was detected in the present range of the excitation intensity. The molar absorption coefficient obtained by this method was verified by the numerical analysis of the excitation intensity dependence of the transient absorbance by taking into account the inner filter effect (absorption of the excitation light by the S1 state produced by the leading part of the pump pulse) and the decrease of the ground state molecules by the pump process (depletion). In addition, these molar absorption coefficients were confirmed by the comparison of relations between the excitation intensity and the transient absorbance of the S1 state under the condition where the fraction of the excited solute is ≪ 10% by the femtosecond pulsed laser excitation. From these results, the error of the molar absorption coefficients was estimated to be < 5%. These values can be used as reference ones for the estimation of molar absorption coefficients of other systems leading to the quantitative elucidation of the photochemical reactions detected by the transient absorption spectroscopy.

Glycated albumin as biomarker: Evidence and its outcomes.

Glycemic control markers are important for the diagnosis and treatment of diabetes. Hemoglobin A1c (A1C) is an important marker that is mandatory in routine medical examinations; however, it is well known that it has some limitations. In this review, we focus on the limitation of A1C and introduce a relatively new marker, glycated albumin (GA), which can be used to complement A1C. First, for a better understanding of the characteristics of each marker, we sort the similarities and differences of glycemic control markers as well as the characteristics of each marker. Second, we point out the limitation of A1C, introduce GA as an alternative indicator, and discuss the limitations of GA. Finally, we summarize important evidence regarding the utility of GA. We hope that this review provides useful information that permits more effective usage of GA as well as other glycemic control markers.

HbA1c levels Measured by Enzymatic Assay and Immunoassay during Off-Site Health Checkups Are Both Lower than Those Measured by On-Site HPLC Assay.

It has already been reported that HbA1c levels measured by immunoassay (IA) (IA-HbA1c) during off-site health checkups present falsely lower results. We also reported that HbA1c levels measured by enzymatic assay (EA) (EA-HbA1c) during off-site health checkups are lower. In the present study, we compared IA-HbA1c levels or EA-HbA1c levels during off-site health checkups with on-site high-performance liquid chromatography (HPLC)-HbA1c levels using the same samples. Subjects were 88 non-diabetic individuals who had health checkups in Nishinomiya Municipal Central Hospital. Subjects with a history of diabetes mellitus and those with HPLC-HbA1c ≥ 6.5% were excluded. IA-HbA1c levels (Study 1) or EA-HbA1c levels (Study 2) in the health checkups were compared with on-site HPLC-HbA1c levels using the same samples. Both IA-HbA1c levels and EA-HbA1c levels had positive correlations with HPLC-HbA1c levels (p <0.0001 for both), although both were significantly lower than HPLC-HbA1c levels (p <0.0001 for both). The degrees of reductions in the IA-HbA1c levels and EA-HbA1c levels compared with HPLC-HbA1c levels were almost same to each other. Similarly to IA-HbA1c levels, EA-HbA1c levels during the health checkups were lower than HPLC-HbA1c levels. It was demonstrated that HbA1c levels decrease similarly if measured by either EA or IA during off-site health checkups.