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Improving the chromatographic separation of phosphorothioate oligonucleotide from impurities by optimizing selectivity through mobile-phase conditions in Ion-pair reversed-phase high-performance liquid chromatography

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JOURNAL OF CHROMATOGRAPHY A 2025年 1750卷 465915页

作者： obata, yuki Sakamaki, Hiroshi Chem Evaluat & Res Inst 1600 ShimotakanoSugito Machi Saitama 3450043 Japan

A diastereomer peak broadening has been observed in phosphorothioate (PS) oligonucleotide analysis in several modes of high-performance liquid chromatography (HPLC). PS oligonucleotide impurities are of various types, and their physicochemical properties are similar to those of PS oligonucleotides. Consequently, quality control requires the chromatographic separation of PS oligonucleotide from impurities and separation of impurities from one another, which is challenging. In this study, to optimize the selectivity for effectively separating PS oligonucleotide from its impurities such as phosphodiester impurities (POs) and n-1 truncated sequences (n-1 s) in ion-pair reversed-phase (IP-RP) HPLC, the effect of mobile-phase conditions on the selectivity was investigated. Most importantly, it was demonstrated that the selectivity for the diastereomers of PS oligonucleotides is optimally reduced by the ion-pair (IP) system using alkylamine with a tertiary or quaternary structure and alkyl chain lengths of >= 4, using a method of observing the peak widths of PS oligonucleotides. Alternatively, using counterion species, such as hydrophobic alkyl carboxylic acid, improves the selectivity between the PS oligonucleotide and its impurities. Consequently, the IP system using tributylamine and heptanoic acid is proposed as the system that has optimal selectivity. This system can separate PS oligonucleotides from spiked PO and n-1 groups involving those with different positions and has outstanding quantitative performance at the 0.2 %-5 % range. This study provides a guidance for optimizing the selectivity for IP-RP HPLC, and the proposed IP system could be useful for ensuring the quality control of antisense oligonucleotides including PS linkages.

关键词： Ion-pair reversed-phase high-performance liquid chromatography Phosphorothioate oligonucleotide Diastereomer Phosphodiester impurity Selectivity Counterion

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Effects of Porous Structure of Separation Column on Chromatograms Obtained by Phase-Separation Mode in HPLC

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CHROMATOGRAPHIA 2025年第3期88卷 215-224页

作者： Katayama, Tetsuro Iharada, Takeshi obata, yuki Sakamaki, Hiroshi Tsukagoshi, Kazuhiko Doshisha Univ Grad Sch Sci & Engn Appl Chem Kyotanabe 6100321 Japan Chem Evaluat & Res Inst 1600 ShimotakanoSugito Machi Saitama 3450043 Japan

A novel HPLC system utilizing a phase-separation multiphase flow as the eluent has been developed, referred to as phase-separation mode. This research explores the influence of the porous structure in an octadecyl-modified silica (ODS) column (with a pore diameter of 12 nm) on chromatographic outcomes under the phase-separation mode in HPLC. The chromatograms obtained from the porous ODS column were compared to those generated with a non-porous ODS column. In preliminary experiments, twenty-four mixed solutions, comprising combinations of water/acetonitrile/ethyl acetate and water/acetonitrile, were introduced as eluents at a column temperature of 20 degrees C. A model mixture of 2,6-naphthalenedisulfonic acid (2,6-NDS) and 1-naphthol (1-NA) was injected into the system, with separation achieved in most solutions except for some highly organic solvent-rich solutions where 2,6-NDS eluted faster than 1-NA, indicating reverse-phase mode operation. Subsequently, the separation of the model mixture was assessed at 0 degrees C, and four specific ternary mixtures were analyzed in detail at both 20 degrees C and 0 degrees C. These ternary mixtures, defined by their volume ratios, exhibited a two-phase separation, establishing a phase-separation multiphase flow. Consequently, the solution flow was homogeneous at 20 degrees C and heterogeneous at 0 degrees C. For instance, solutions with water/acetonitrile/ethyl acetate ratios of 20:60:20 (organic solvent-rich) and 70:23:7 (water-rich) were introduced as eluents at both 20 degrees C and 0 degrees C. At 0 degrees C in the organic solvent-rich eluent, 1-NA eluted faster than 2,6-NDS, characteristic of the phase-separation mode. In contrast, the water-rich eluent resulted in faster elution of 2,6-NDS at both temperatures. The porous ODS column displayed improved separation efficiency at 0 degrees C compared to the non-porous column, which can be attributed to the porous effect under phase-separation conditions.

关键词： Phase-separation multiphase flow Phase-separation mode Porous ODS column HPLC

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Development of a HPLC system using a phase-separation multiphase flow as an eluent coupled to a silica-particle packed column

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ANALYTICAL SCIENCES 2023年第9期39卷 1483-1491页

作者： Kinoshita, Satoru Ishikawa, Daiki Kobayashi, yuki obata, yuki Sakamaki, Hiroshi Iharada, Takeshi Tsukagoshi, Kazuhiko Doshisha Univ Grad Sch Sci & Engn Appl Chem Kyotanabe 6100321 Japan Chem Evaluat & Res Inst Saitama 3450043 Japan

The study reports the development of a high-performance liquid chromatography (HPLC) system in which a phase-separation multiphase flow as the eluent and a silica-particle based packed column as the separation column were combined to form the phase separation mode. Twenty-four types of mixed solutions of water/acetonitrile/ethyl acetate and water/acetonitrile were applied as eluents to the system at 20 degrees C. 2,6-Naphthalenedisulfonic acid (NDS) and 1-naphthol (NA) were injected as model analytes into the system. They showed separation tendency in organic solvent-rich eluents in normal-phase mode and NA was detected earlier than NDS. Subsequently, seven types of the ternary mixed solutions were examined as eluents in the HPLC system at 20 degrees C and 0 degrees C. These mixed solutions worked as a two-phase separation mixed solution, providing a phase-separation multiphase flow at 0 degrees C in the separation column. In the organic solvent-rich eluent, the mixture of analytes was separated at both 20 degrees C (normal-phase mode) and 0 degrees C (phase-separation mode), with NA being detected earlier than NDS. The separation at 0 degrees C was more efficient than at 20 degrees C. In the water-rich eluent, the mixture of NDS and NA was not separated at 20 degrees C but was separated at 0 degrees C (phase-separation mode), with NDS being detected earlier than NA. We also discussed the separation mechanism of phase-separation mode in HPLC together with the computer simulation for the multiphase flow in the cylindrical tube having sub-pm inner diameter.

关键词： HPLC Phase-separation multiphase flow Phase-separation mode Silica-particle packed column

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Relative risk of gastric cancer between those with and without Helicobacter pylori infection history in Japan

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JGH OPEN 2022年第3期6卷 166-170页

作者： Kikuchi, Shogo obata, yuki Sasakabe, Tae Kawai, Sayo Wang, Chaochen Lin, Yingsong Aichi Med Univ Dept Publ Hlth Sch Med 1-1 Yazakokarimata Nagakute Aichi 4801195 Japan Kinjo Gakuin Univ Coll Pharm Nagoya Aichi Japan

Background and Aim: The causal relationship between Helicobacter pylori (H. pylori) infection and gastric cancer has been established. Although the magnitude of the carcinogenic effect of H. pylori is the next concern, it has not been sufficiently evaluated in Japan. Spontaneous disappearance of H. pylori infection may have provoked underestimation of the carcinogenic effect of the infection. To reduce the influence, a comparison should be carried out between subjects with and without the infection history. Cutoff values of H. pylori antibody lower than the manufacturer's recommendation are known to be more appropriate to diagnose history of H. pylori infection. The aim was to evaluate the carcinogenic effect of H. pylori. Methods: A case-control study consisting of 275 gastric cancer patients and 275 age- and sex-matched controls was performed. Serum H. pylori antibody was measured using the "JHM-Cap" kit with a domestic antigen (cut value of the manufacturer's recommendation was 2.3 EV: ELISA value). Using a conditional logistic model, the odds ratios (ORs) for five cutoff values adjusted for smoking and drinking doses were calculated. Results: For cutoff values of 1.25, 1.5, 1.75, 2.0, and 2.3 EV, the ORs (95% confidence intervals) were 67.7 (9.1, 502), 37.2 (8.8, 157), 21.3 (9.0, 60.2), 25.5 (9.0, 72.7), and 25.9 (9.2, 73.2), respectively. Conclusions: These results suggest that the risk ratio of gastric cancer between subjects with and without history of H. pylori infection in Japan may exceed 20.

关键词： case-control study seroreversion spontaneous disappearance

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Serum transforming growth factor-β1 levels and pancreatic cancer risk:: a nested case-control study (Japan)

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CANCER CAUSES & CONTROL 2006年第8期17卷 1077-1082页

作者： Lin, Yingsong Kikuchi, Shogo Tamakoshi, Akiko obata, yuki Yagyu, Kiyoko Inaba, Yutaka Kurosawa, Michiko Kawamura, Takashi Motohashi, Yutaka Ishibashi, Teruo Aichi Med Univ Sch Med Dept Publ Hlth Aichi Aichi 4801195 Japan Nagoya Univ Grad Sch Med Dept Prevent Med Biostat & Med Decis Making Nagoya Aichi Japan Juntendo Univ Sch Med Dept Epidemiol & Environm Hlth Tokyo 113 Japan Kyoto Univ Ctr Student Hlth Kyoto Japan Akita Univ Sch Med Dept Publ Hlth Akita 010 Japan Asama Gen Hosp Nagano Japan

Objective To examine the relationship of baseline levels of serum TGF-beta 1 to the subsequent risk of death from pancreatic cancer in a nested case-control study. Methods The cases were 85 persons who had provided a blood sample at baseline and subsequently died of pancreatic cancer during the study period. For each case, three controls were randomly selected from among the cohort participants, and were matched for each case by sex, age (+/- 1 year), and study area. Serum TGF-beta 1 levels were measured with enzyme-linked immunosorbent assay (ELISA). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated from conditional logistic models. Results The mean of serum TGF-beta 1 levels was significantly higher among cases than among controls (p = 0.01). Individuals with serum TGF-beta 1 levels in the highest quartile had a 2.5-fold increase in risk as compared with those in the lowest quartile (OR, 2.5;95% CI, 0.9-6.9), after adjustment for month of blood draw, cigarette smoking, body mass index and history of diabetes. Excluding 12 pancreatic cancer deaths that occurred within three years of follow-up did not alter the positive association. Conclusion Our prospective data indicate that high serum TGF-beta 1 levels may be associated with an increased risk of death from pancreatic cancer.

关键词： pancreatic cancer Serum Transforming Growth Factor-beta 1 nested case-control study

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Obesity, physical activity and the risk of pancreatic cancer in a large Japanese cohort

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INTERNATIONAL JOURNAL OF CANCER 2007年第12期120卷 2665-2671页

作者： Lin, Yingsong Kikuchi, Shogo Tamakoshi, Akiko Yagyu, Kiyoko obata, yuki Inaba, Yutaka Kurosawa, Michiko Kawamura, Takakshi Motohashi, Yutaka Ishibashi, Teruo Aichi Med Univ Sch Med Dept Publ Hlth Aichi Japan Nagoya Univ Grad Sch Med Dept Prevent Med Biostat & Med Decis Making Nagoya Aichi Japan Juntendo Univ Sch Med Dept Epidemiol & Environm Hlth Tokyo 113 Japan Kyoto Univ Ctr Student Hlth Kyoto Japan Akita Univ Sch Med Dept Publ Hlth Akita 010 Japan Asama Gen Hosp Saku Japan

It is unclear whether body mass index (BMI) and physical activity are associated with the risk of pancreatic cancer in Asian populations. We examined these associations in the Japanese Collaborative Cohort Study for Evaluation of Cancer Risk. Our cohort study included 110,792 Japanese men and women at enrollment (1988-1990). Data on height, body weight (at baseline and age 20 years) and physical activity were obtained from a questionnaire. Cox proportional hazards models were used to estimate the relative risks of pancreatic cancer mortality. We observed a total or 402 pancreatic cancer deaths during the follow-up period. Men with a BMI of 30 or more at age 20 years had a 3.5-fold greater risk compared with men with a normal BMI. Women with a BMI of 27.5-29.9 at baseline had similar to 60% increased risk compared with women with a BMI of 20.0-22.4. In men, weight loss of 5 kg or more between 20 years of age and baseline age was associated with an increased risk of pancreatic cancer death. In contrast, women with weight loss of 5 kg or more over the same period had a decreased risk. Physical activity was not associated with pancreatic cancer risk in either men or women. Obesity in young adulthood may be associated with an increased risk of death from pancreatic cancer in Japanese men. The risk of pancreatic cancer in relation to BMI seems to differ according to sex and the period over which BMI was measured. (c) 2007 Wiley-Liss, Inc.

关键词： body mass index physical activity pancreatic cancer obesity relative risk cohort study

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Association of menstrual and reproductive factors with pancreatic cancer risk in women: findings of the Japan Collaborative Cohort Study for Evaluation of Cancer Risk

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JOURNAL OF GASTROENTEROLOGY 2006年第9期41卷 878-883页

作者： Lin, Yingsong Kikuchi, Shogo Tamakoshi, Akiko Kawamura, Takashi Inaba, Yutaka Kurosawa, Michiko Motohashi, Yutaka Yagyu, Kiyoko obata, yuki Ishibashi, Teruo Aichi Med Univ Sch Med Dept Publ Hlth Aichi 4801195 Japan Nagoya Univ Grad Sch Med Dept Prevent Med Biostat & Med Decis Making Nagoya Aichi Japan Kyoto Univ Ctr Student Hlth Kyoto Japan Juntendo Univ Sch Med Dept Epidemiol & Environm Hlth Tokyo 113 Japan Akita Univ Sch Med Dept Publ Hlth Akita 010 Japan Asama Gen Hosp Saku Japan

Background The etiology of pancreatic cancer remains largely unknown. We examined the association of pancreatic cancer deaths with menstrual and reproductive factors in a cohort study involving Japanese women. Methods. A total of 63273 women were followed up for mortality from 1988 to 1999. Information on menstrual and reproductive factors was obtained by a questionnaire survey at baseline. Cox proportional-hazards models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for death from pancreatic cancer in relation to menstrual and reproductive factors. Results. During 631401 person-years of follow-up, 154 women died from pancreatic cancer. Parity was not significantly associated with the risk of death from pancreatic cancer;the RR was 0.80 (95% CI, 0.31-2.11) for women with six or more births compared with women with zero or one birth. We found no significant overall association with other reproductive factors, including pregnancy, age at first birth, and menopause. The risk appeared to increase with increasing age at menarche;the RR was 1.49 (95% CI, 0.95-2.34) for women who had menarche after 16 years of age compared to those who had menarche before they were 15 years old. Conclusions. Our prospective data indicate that menstrual and reproductive factors are not associated with the risk of death from pancreatic cancer among Japanese women.

关键词： pancreatic cancer parity reproductive factor cohort study risk

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Dietary habits and pancreatic cancer risk in a cohort of middle-aged and elderly Japanese

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NUTRITION AND CANCER-AN INTERNATIONAL JOURNAL 2006年第1期56卷 40-49页

作者： Lin, Yingsong Kikuchi, Shogo Tamakoshi, Akiko Yagyu, Kiyoko obata, yuki Inaba, Yutaka Kurosawa, Michiko Kawamura, Takashi Motohashi, Yutaka Ishibashi, Teruo Aichi Med Univ Sch Med Dept Publ Hlth Nagakute Aichi 4801195 Japan Nagoya Univ Grad Sch Med Dept Prevent Med Biostat & Med Decis Making Nagoya Aichi Japan Juntendo Univ Sch Med Dept Epidemiol & Environm Hlth Tokyo 113 Japan Kyoto Univ Ctr Student Hlth Kyoto Japan Akita Univ Sch Med Dept Publ Hlth Akita 010 Japan Asama Gen Hosp Nagano Japan

Few epidemiological studies have examined associations between diet and pancreatic cancer in Japan. In the Japan Collaborative Cohort Study for Evaluation of Cancer Risk, we evaluated the relationship between dietary factors, including meat, vegetable, and fruit intake, and the risk of pancreatic cancer deaths. Among the original cohort established between 1988 and 1990, 46,465 men and 64,327 women aged 40-79 yr were followed-up through December 31,1999. During 1,042,608 person-years of follow-up, we documented 300 deaths from pancreatic cancer. A 33-item food-frequency questionnaire was used to assess dietary intake at the baseline survey. Cox proportional-hazards models were used to estimate the relative risks of pancreatic cancer death in relation to the intake frequency of food items. We did not observe an overall association between meat intake and pancreatic cancer risk. Except for a 50% decrease in risk associated with high fruit intake among men, we did not find other significant inverse relationships between vegetable and fruit intake and pancreatic cancer risk. Smoking did not modify the associations with dietary habits. Our study suggested that high consumption of pickles and wild edible plants, mainly bracken, might be related to increased pancreatic cancer risk;however this finding should be confirmed in other epidemiological studies.

关键词： Malignant neoplasm of pancreas Risk cohort Fruit With frequency

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High expression of long non-coding RNA MALAT1 in breast cancer is associated with poor relapse-free survival

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BREAST CANCER RESEARCH AND TREATMENT 2018年第2期171卷 261-271页

作者： Wang, Zhanwei Katsaros, Dionyssios Biglia, Nicoletta Shen, Yi Fu, Yuanyuan Loo, Lenora W. M. Jia, Wei obata, yuki Yu, Herbert Univ Hawaii Canc Epidemiol Program Ctr Canc 701 Ilalo St Honolulu HI 96813 USA Univ Torino Dept Surg Sci Sch Med GynecolAOU Citta Salute Turin Italy Univ Torino Mauriziano Hosp Div Obstet & Gynecol Dept Surg SciSch Med Turin Italy Univ Hawaii Manoa Dept Mol Biosci & Bioengn Honolulu HI 96822 USA Kinjo Gakuin Univ Coll Pharm Nagoya Aichi Japan

Purpose Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been identified as a prognostic marker for the metastasis of early-stage non-small cell lung cancer (NSCLCs). We studied MALAT1 expression in breast cancer in relation to disease features and patient survival. Methods Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to measure MALAT1 expression in tumor samples of 509 breast cancer patients. Hazards ratios (HRs) and 95% confidence intervals (CIs) were calculated to assess the association between MALAT1 expression and breast cancer survival using the Cox proportional hazards regression model, and the analysis was adjusted for age at surgery, tumor grade, disease stage, and hormone receptor status. Meta-analysis of multiple microarray datasets from online databases and our own study was performed to evaluate the association of MALAT1 with breast cancer survival. Results Patients with low-grade or ER-positive tumors had higher expression of MALAT1 compared to those with high-grade (p = 0.013) or ER-negative (p = 0.0002) tumors. Patients with PR-positive tumors also had higher MALAT1 expression than those with PR-negative tumors (p < 0.0001). In patients with positive hormone receptors or low tumor grade, tumors with high MALAT1 expression were more likely to recur. Survival analysis showed that patients with high expression of MALAT1 had a twofold increase in risk of relapse (p = 0.0083) compared to those with low expression. This association remained significant after adjustment for age at surgery, disease stage, tumor grade, and hormone receptor status. Meta-analysis showed that high MALAT1 expression was associated with poor relapse-free survival in patients with hormone receptor-positive tumors (HR 1.44, 95% CI 1.08-1.92). Conclusions High expression of lncRNA MALAT1 is associated with breast cancer relapse and may play a role in tumor progression.

关键词： MALAT1 Breast cancer Estrogen receptor Survival Meta-analysis

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Resting-state brain functional connectivity in patients with chronic intractable pain who respond to spinal cord stimulation therapy

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BRITISH JOURNAL OF ANAESTHESIA 2025年第2期134卷 492-500页

作者： Ueno, Kyohei Oshiro, Yoshitetsu Kan, Shigeyuki Nomura, yuki Satou, Hitoaki obata, Norihiko Mizobuchi, Satoshi Kobe Univ Grad Sch Med Dept Anesthesiol Kobe Hyogo Japan Ritsumeikan Univ Res Org Sci & Technol Kusatsu Shiga Japan

Background: Spinal cord stimulation (SCS) is widely accepted as a useful treatment for patients with intractable chronic pain. However, its effectiveness varies between individuals. Therefore, a tool for evaluating its effectiveness in advance is eagerly awaited. We examined whether resting-state functional magnetic resonance imaging as a diagnostic and prognostic tool can predict responsiveness to SCS. Methods: Twenty-nine patients with intractable chronic pain participated in this study. Participants were divided into responder and non-responder groups based on a pain relief rate after SCS trials. All participants underwent resting-state functional magnetic resonance imaging scans before the SCS trials. We searched for functional connectivity that differed significantly in strength between the two groups and was correlated with pain relief rate. We conducted receiver operating characteristic (ROC) analysis and a one-sample proportion test to determine the cut-off value and evaluate the predictive power of the functional connectivity-based prediction model. Results: In total, 14 and 15 participants were assigned to the responder and non-responder groups, respectively. Functional connectivity between the middle anterior cingulate cortex and precuneus/posterior cingulate cortex showed significant between-group differences and a significant negative correlation with the pain relief rate. Moreover, this functional connectivity could accurately predict SCS responsiveness greater than chance (sensitivity: 71%;specificity: 87%;area under the curve: 0.814;P<0.001). Conclusions: For patients with intractable chronic pain, functional connectivity between the middle anterior cingulate cortex and precuneus/posterior cingulate cortex is a promising candidate biomarker to estimate responsiveness to spinal cord stimulation before treatment.

关键词： anterior cingulate cortex chronic intractable pain default mode network functional connectivity functional MRI precuneus spinal cord stimulation

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