Biochemical analyses of lipids deposited on silicone hydrogel lenses

AbstractPurposeThis study was performed to determine the levels of lipids deposited on in vivo worn silicone hydrogel lenses.MethodsThree silicone hydrogel materials, galyfilcon A, senofilcon A, and asmofilcon A, were worn for 2 weeks by 35 normal subjects. Total lipid deposition was determined by the sulfo-phospho-vanillin reaction. Cholesterol was estimated by a colorimetric probe through enzymatic oxidation. Phospholipid level was estimated by determining phosphorus with ammonium molybdate through enzymatic digestion.ResultsThe total lipid content recovered from galyfilcon A, senofilcon A, and asmofilcon A was 32.9 ± 33.8, 42.1 ± 14.0, and 36.6 ± 31.9 μg/lens, respectively. The cholesterol content recovered from galyfilcon A, senofilcon A, and asmofilcon A was 26.2 ± 26.9, 28.6 ± 19.4, and 31.1 ± 21.1 μg/lens, respectively. There were no statistically significant differences in total lipids and cholesterol among the contact lens types. However, the quantity of phospholipid recovered from the asmofilcon A (7.0 ± 5.5 μg/lens) lenses was significantly higher than from galyfilcon A (1.1 ± 0.8 μg/lens) and senofilcon A (2.4 ± 0.8 mg/lens) lenses (p < 0.05, Mann-Whitney test).ConclusionsThe quantity of total lipid and cholesterol deposited on the 3 silicone hydrogel lenses tested did not differ. However, there were significant differences in the amounts of phospholipid deposited among the 3 silicone hydrogel lenses, of which clinical significance should be explored in the future study

Development of HANABI, an ultrasonication-forced amyloid fibril inducer

Goto Y., Nakajima K., Yamaguchi K., et al. Development of HANABI, an ultrasonication-forced amyloid fibril inducer. Neurochemistry International 153, 105270 (2022); https://doi.org/10.1016/j.neuint.2021.105270.Amyloid fibrils involved in amyloidoses are crystal-like aggregates, which are formed by breaking supersaturation of denatured proteins. Ultrasonication is an efficient method of agitation for breaking supersaturation and thus inducing amyloid fibrils. By combining an ultrasonicator and a microplate reader, we developed the HANABI (HANdai Amyloid Burst Inducer) system that enables high-throughput analysis of amyloid fibril formation. Among high-throughput approaches of amyloid fibril assays, the HANABI system has advantages in accelerating and detecting spontaneous amyloid fibril formation. HANABI is also powerful for amplifying a tiny amount of preformed amyloid fibrils by seeding. Thus, HANABI will contribute to creating therapeutic strategies against amyloidoses by identifying their biomarkers

フォトダイオードアレイ検出HPLC を用いた微分クロマトグラフ法によるカフェインの定量

We assessed caffeine levels in bathwater and diluted urine samples by derivative processing of chromatograms obtained through the use of HPLC with photodiode array detection. Chromatograms were differentiated on the basis of d（Abs）/d（min）．The peak position of the target analyte, caffeine, was observed to shift depending on the derivative order applied, but was constant when applying the same derivative order, such that retention times were constant even after differentiation. When the method detection limit was examined using standard solutions, the varying absorption of acetonitrile during a linear gradient elution from 1 to 100 % acetonitrile was shown to have an effect, such that the linearity of the peak height deteriorated if caffeine was present at low concentrations. Recovery of caffeine from real samples was optimized in the case of both linear gradient elution and isocratic elution（ 10 % acetonitrile）when applying the second derivative and using a detection wavelength of 259 nm. Interestingly, this does not correspond to the maximum absorption of caffeine. Thus the optimum wavelength for use with this differential chromatographic method is one that is not affected by the absorbance of the eluent and at which the target analyte shows significant absorbance, even if it is not the maximum absorbance. Such conditions were found to be necessary for the high-sensitivity measurement of caffeine. It is believed that this method is applicable to the HPLC analysis of compounds other than caffeine and this technique is expected to be effective when applied to an automated analyzer and should be helpful to analysts unfamiliar with HPLC.フォトダイオードアレイ検出HPLC を用いた微分クロマトグラフ法による希釈尿あるいは風呂水からのカフェインの回収について検討した。通常のクロマトグラムを微分（d（Abs）/d（min））し，微分クロマトグラムを得る。目的の化合物のピーク位置は，微分次数によるずれるが，同じ微分次数で比較すると一定しており，保持時間による定性能は微分後も維持されていた。標準溶液を用いた定量下限値は，リニアグラジエント溶出（1 → 100 ％アセトニトリル）では溶離液として用いたアセトニトリルの吸収が影響を与え，カフェインが低濃度の場合にはピーク高さとの直線性が悪化した。実試料からのカフェインの回収は，波長259 nm，2 次微分実行時にリニアグラジエント溶出，アイソクラティック溶出（10 ％アセトニトリル）共最適であった。この条件は必ずしもカフェインが極大吸収を持つ波長，微分次数ではない。本結果は微分クロマトグラフ法での検出条件として，1）溶離液吸収の影響を受け難い波長を選択すること，2）目的物質であるカフェインの吸光度が極大でなくてもある程度大きいことが高感度測定に必要であることを示す。今回の結果はカフェインのみならず，他の化合物をHPLC 分析する場合，特にHPLC に不慣れな使用者が条件検討する場合や自動分析装置に応用する場合にも利用可能な知見であると考えられる

Half-Time Heat Map Reveals Ultrasonic Effects on Morphology and Kinetics of Amyloidogenic Aggregation Reaction

Nakajima K., Toda H., Yamaguchi K., et al. Half-Time Heat Map Reveals Ultrasonic Effects on Morphology and Kinetics of Amyloidogenic Aggregation Reaction. ACS Chemical Neuroscience 12, 3456 (2021); https://doi.org/10.1021/acschemneuro.1c00461.Ultrasonication has been recently adopted in amyloid-fibril assays because of its ability to accelerate fibril formation, being promising in the early stage diagnosis of amyloidoses in clinical applications. Although applications of this technique are expanding in the field of protein science, its effects on the aggregation reactions of amyloidogenic proteins are poorly understood. In this study, we comprehensively investigated the morphology and structure of resultant aggregates, kinetics of fibril formation, and seed-detection sensitivity under ultrasonication using β2-microglobulin and compared these characteristics under shaking, which has been traditionally adopted in amyloid-fibril assays. To discuss the ultrasonic effects on the amyloid-fibril formation, we propose the half-time heat map, which describes the phase diagram of the aggregation reaction of amyloidogenic proteins. The experimental results show that ultrasonication greatly promotes fibril formation, especially in dilute monomer solutions, induces short-dispersed fibrils, and is capable of detecting ultra-trace-concentration seeds with a detection limit of 10 fM. Furthermore, we indicate that ultrasonication highly alters the energy landscape of an aggregation reaction due to the effect of ultrasonic cavitation. These insights contribute not only to our understanding of the effects of agitation on amyloidogenic aggregation reactions but also to their effective application in the clinical diagnosis of amyloidoses

Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ~10 pc. The convex radio spectrum is stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age of the order of ~100 years as a radio source, according to an observed correlation between linear size and peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.Comment: 7 pages, 2 figures, 2 tables, accepted for publication in PAS

Ultrastiff Amyloid-Fibril Network of α-Synuclein Formed by Surface Seeding Reaction Confirmed by Multichannel Electrodeless Quartz-Crystal-Microbalance Biosensor

Zhou L., Hajiri T., Nakajima K., et al. Ultrastiff Amyloid-Fibril Network of α-Synuclein Formed by Surface Seeding Reaction Confirmed by Multichannel Electrodeless Quartz-Crystal-Microbalance Biosensor. ACS Sensors 8, 2598 (2023); https://doi.org/10.1021/acssensors.3c00331.We developed a multichannel wireless quartz-crystal-microbalance (QCM) biosensor for mechanically studying the on-surface aggregation reaction of α-synuclein (α-syn). We find a quite unusual change in the resonant frequency that eventually exceeds the baseline, which has never been observed during seeding aggregation reaction. By incorporating a growth-to-percolation theory for fibril elongation reaction, we have favorably reproduced this unusual response and found that it can be explained only with formation of an ultrastiff fibril network. We also find that the stiffness of the fibril network grown from artificially prepared twist-type seeds is significantly higher than that from rod-type seeds. Furthermore, the stiffnesses of fibril networks grown from seeds derived from brain tissues of Parkinson’s disease (PD) and multiple system atrophy (MSA) patients show a very similar trend to those of rod and twist seeds, respectively, indicating that fibrils from MSA patients are stiffer than those from PD

Novel protein extraction approach using micro-sized chamber for evaluation of proteins eluted from formalin-fixed paraffin-embedded tissue sections

We describe a novel antigen-retrieval method using a micro-sized chamber for mass spectrometry (MS) analysis to identify proteins that are preferentially eluted from formalin-fixed paraffin-embedded (FFPE) samples. This approach revealed that heat-induced antigen retrieval (HIAR) from an FFPE sample fixed on a glass slide not only improves protein identification, but also facilitates preferential elution of protein subsets corresponding to the properties of antigen-retrieval buffers. Our approach may contribute to an understanding of the mechanism of HIAR

Study protocol of the SACURA trial: a randomized phase III trial of efficacy and safety of UFT as adjuvant chemotherapy for stage II colon cancer

BACKGROUND: Adjuvant chemotherapy for stage III colon cancer is internationally accepted as standard treatment with established efficacy, but the usefulness of adjuvant chemotherapy for stage II colon cancer remains controversial. The major Western guidelines recommend adjuvant chemotherapy for “high-risk stage II” cancer, but this is not clearly defined and the efficacy has not been confirmed. METHODS/DESIGN: SACURA trial is a multicenter randomized phase III study which aims to evaluate the superiority of 1-year adjuvant treatment with UFT to observation without any adjuvant treatment after surgery for stage II colon cancer in a large population, and to identify “high-risk factors of recurrence/death” in stage II colon cancer and predictors of efficacy and adverse events of the chemotherapy. Patients aged between 20 and 80 years with curatively resected stage II colon cancer are randomly assigned to a observation group or UFT adjuvant therapy group (UFT at 500–600 mg/day as tegafur in 2 divided doses after meals for 5 days, followed by 2-day rest. This 1-week treatment cycle is repeated for 1 year). The patients are followed up for 5 years until recurrence or death. Treatment delivery and adverse events are entered into a web-based case report form system every 3 months. The target sample size is 2,000 patients. The primary endpoint is disease-free survival, and the secondary endpoints are overall survival, recurrence-free survival, and incidence and severity of adverse events. In an additional translational study, the mRNA expression of 5-FU-related enzymes, microsatellite instability and chromosomal instability, and histopathological factors including tumor budding are assessed to evaluate correlation with recurrences, survivals and adverse events. DISCUSSION: A total of 2,024 patients were enrolled from October 2006 to July 2010. The results of this study will provide important information that help to improve the therapeutic strategy for stage II colon cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT00392899

Macromolecular crowding and supersaturation protect hemodialysis patients from the onset of dialysis-related amyloidosis

Nakajima K., Yamaguchi K., Noji M., et al. Macromolecular crowding and supersaturation protect hemodialysis patients from the onset of dialysis-related amyloidosis. Nature Communications 13, 5689 (2022); https://doi.org/10.1038/s41467-022-33247-3.Dialysis-related amyloidosis (DRA), a serious complication among long-term hemodialysis patients, is caused by amyloid fibrils of β2-microglobulin (β2m). Although high serum β2m levels and a long dialysis vintage are the primary and secondary risk factors for the onset of DRA, respectively, patients with these do not always develop DRA, indicating that there are additional risk factors. To clarify these unknown factors, we investigate the effects of human sera on β2m amyloid fibril formation, revealing that sera markedly inhibit amyloid fibril formation. Results from over 100 sera indicate that, although the inhibitory effects of sera deteriorate in long-term dialysis patients, they are ameliorated by maintenance dialysis treatments in the short term. Serum albumin prevents amyloid fibril formation based on macromolecular crowding effects, and decreased serum albumin concentration in dialysis patients is a tertiary risk factor for the onset of DRA. We construct a theoretical model assuming cumulative effects of the three risk factors, suggesting the importance of monitoring temporary and accumulated risks to prevent the development of amyloidosis, which occurs based on supersaturation-limited amyloid fibril formation in a crowded milieu