Temperature-responsive chromatography.
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Journal Article↗
Biomedical subjects
Y Matsushima
Publications and source records attributed to Y Matsushima.
Reaction of 2,2,5,7,8-pentamethyl-6-chromanol, an alpha-tocopherol analogue, with NO in the presence of oxygen.
An alpha-tocopherol model compound, 2,2,5,7,8-pentamethyl-6-chromanol, reacted with nitric oxide (NO) in the presence of various amounts of oxygen to afford four major products. Distribution of the products was varied depending on the ratio of NO and O2, and the preincubation time of NO and O2.
Antioxidants↗
Temperature-responsive chromatographic separation of amino acid phenylthiohydantions using aqueous media as the mobile phase.
Recently, green chemistry has become one of the most important subjects of science for environmental pollution prevention. Here, we report development of a novel chromatographic technology for phenylthiohydantoin (PTH)-amino acid analyses in which only aqueous solution is used as the mobile phase. We have devised HPLC adsorbents (stationary phase) by modifying the surfaces of microparticulate silica gel using functional polymers. The thermoresponsive copolymer, poly(N-isopropylacrylamide-co-n-butyl methacrylate) (IBc) was used to modify the silica stationary phase surfaces. This polymer-grafted surface exhibits temperature-regulated hydrophilic/hydrophobic property changes in water. PTH-amino acid interactions with this surface are readily modulated by changing the column temperature using an isocratic aqueous mobile phase. Increasing hydrophobic interactions between more hydrophobic PTH-amino acids with hydrophobized polymer-grafted surfaces at elevated mobile phase temperatures is used for the effective separation of PTH-amino acids in aqueous solution. This study is aimed at the development of novel separation processes, which are also environmentally benign, for use with biochemical substances in order to meet the growing needs of the life sciences and biotechnology. The method is useful for various separations in life science so that proteins can maintain their biological activity and enzymes, their enzymatic activity.
Amino Acids↗
Stereospecific analysis of lorazepam in plasma by chiral column chromatography with a circular dichroism-based detector.
The chiral separation of lorazepam was achieved on a chiral column with UV and circular dichroism (CD) detection. The good resolution of lorazepam enantiomers was obtained on the column of beta-cyclodextrin derivative immobilized silica gel under reversed-phase conditions. The enantiomeric separation and identification of lorazepam were succeeded by CD detector. The method described allows the quantitation of the stereoisomers of lorazepam in human plasma following the administration of a therapeutic dose of the racemic drug. Chiroptical detection is useful for the pharmacokinetic study of chiral drugs.
Anti-Anxiety Agents↗
Determination of theophylline and its metabolites in biological samples by liquid chromatography-mass spectrometry.
Liquid chromatography-mass spectrometry (LC-MS) is a powerful tool for analysis of drugs and their metabolites. We used a column-switching system in combination with atmospheric pressure chemical ionization LC-MS (LC-APCI-MS) for the determination of theophylline and its metabolites in biological samples. The separation was carried out on a reversed-phase column using methanol-20 mM ammonium acetate as a mobile phase at a flow-rate of 1 ml/min in 30 min. In the mass spectrum, the molecular ions of these drugs and metabolites were clearly observed as base peaks. This method is sufficiently sensitive and accurate for the pharmacokinetic studies of these drugs.
Calibration↗
Enantiomeric determination of L- and D-lactic acid in human cerebrospinal fluid by chiral ligand exchange high-performance liquid chromatography.
Enantiomeric determination of L- and D-lactate in human cerebrospinal fluid (CSF) was achieved by HPLC on a chiral stationary phase with UV detection. Samples were submitted to a solid-phase extraction procedure using Oasis HLB Plus Extraction Cartridge and L- and D-lactate in the extract were separated by Shodex ORpac CRX-453 B column, a ligand exchange column for chiral separation, using a mobile phase containing copper (II) ion. L- and D-lactate were determined in 25 min. Intra-assay precision in CSF was 4.98% (mean 1.85 mmol/L) for L-lactate and 10.1% (mean 4.96 micromol/L) for D-lactate (n = 5). Detection limits were between 1.0 (L-lactate) and 1.5 (D-lactate) pmol. The mean values (n = 3) of analytical recovery for L- and D-lactate were 95% and 107%, respectively. The mean +/- SD of concentrations of L- and D-lactate in CSF (n = 20) were 1.52 +/- 0.54 mmol/L and 10.98 +/- 5.15 micromol/L, respectively.
Calibration↗
Morphological study on rupture of posterior capsule in RLC mouse lens.
PURPOSE: To clarify the causative factor underlying rupture of the posterior capsule of the RLC mouse lens as a recessive trait around the 50th postnatal day. METHODS: The lenses of the RLC mouse were removed in the period from birth to 50th postnatal day. Some specimens were observed by light microscopy and transmission and scanning electron microscopy. Others were examined as flat preparations of the lens epithelium. RESULTS: There was an abnormal arrangement of lens fibers at the newborn stage, and lens fibers of the perinuclear zone ended almost vertical in relation to the posterior capsule. Consequently, the posterior suture was not formed in this mouse lens. On the 10th postnatal day, the ends of the lens fibers that terminated in the posterior capsule became swollen, and the posterior capsule at the posterior polar region became thin. On the 20th day, the area of swollen fibers was so large at the center of the posterior capsule that a vacuolated area was observed under the dissecting microscope. On the 30th day, the posterior cortical fibers in this area showed marked swelling, and the posterior capsule became extremely thin. On the 40th day, the anterior cortex became unusually thick, and the lens nucleus was dislocated towards the posterior capsule. On the 50th day, the posterior capsule ruptured. At this time the lens fibers from the perinuclear zone constituted the central area of rupture, and the cortical fibers from the equator formed the protruded area outside the lens. CONCLUSION: The findings revealed that the RLC mouse lens has an abnormal lens fiber arrangement from the early period of lens development, that the lens fibers from the perinuclear zone cause swelling without forming the posterior suture, and that the thin capsule is ruptured by pushing out of the nucleus by thickening of the anterior cortex.
Aging↗
Effects of Helicobacter pylori infection on Zollinger-Ellison syndrome.
Both Zollinger-Ellison syndrome (ZES) and Helicobacter pylori infection are major etiologic factors for peptic ulcer. The aim of this study was to investigate the effect of H. pylori infection on ZES with special reference to acid secretion. Sixteen patients with ZES were selected (median age, 59 years; range, 39-66 years; M/F, 9/7), and H. pylori status, ulcer location, gastric acid secretion, serum pepsinogen (PG) I and II concentrations, and PG I/II ratio were determined. The seroprevalence of H. pylori infection was 50%, whereas active H. pylori infection was seen in only 25% of the patients. Thirteen patients had duodenal ulcer (DU), 1 had gastric ulcer (GU), and 2 had both GU and DU. DU was seen in both H. pylori-positive and H. pylori-negative patients, whereas GU was found only in H. pylori-positive patients. Both basal and maximal acid outputs were significantly lower in H. pylori-positive patients than in H. pylori-negative patients (P< 0.05). Moreover, both serum PG I and the PG I/II ratio were significantly lower in H. pylori-positive patients than in H. pylori-negative patients. These results indicate that ZES is an independent risk factor for DU, but H. pylori infection may play some role in the development of GU in ZES. In patients with ZES, H. pylori infection may reduce both hypersecretion from parietal cells and PG I secretion from chief cells, and hyperacidity of the stomach in ZES may have eradicated H. pylori in some patients.
Adult↗
Autoimmune-related pancreatitis is associated with autoantibodies and a Th1/Th2-type cellular immune response.
BACKGROUND & AIMS: Although autoimmunity may be involved in some cases of pancreatitis, the mechanism is still unknown. To clarify this, we studied serum autoantibodies, subsets of lymphocytes, and the Th1/Th2 balance of cellular immune responses in patients with autoimmune-related pancreatitis (AIP). METHODS: Seventeen patients with AIP (8 men and 9 women; age, 53.2 +/- 13.0 years) were studied. Autoantibodies including antilactoferrin (ALF) or carbonic anhydrase II antibody (ACA-II) were examined using the enzyme-linked immunosorbent assay (ELISA) or the indirect fluorescein antibody method. Intracellular cytokines (interferon gamma and interleukin 4) and subtypes of peripheral blood lymphocytes were examined by flow cytometry and ELISA. RESULTS: More than one autoantibody was observed in all 17 patients. Serum antinuclear antibody was detected in 13 of 17 patients, ALF antibody in 13, ACA-II antibody in 10, rheumatoid factor in 5, and anti-smooth muscle antibody in 3, but antimitochondrial antibody in none. The serum levels of ACA-II and LF antibody were not correlated. HLA-DR(+)CD8(+) and HLA-DR(+)CD4(+) cells were significantly increased in peripheral blood (P < 0.05). CD4(+) cells producing interferon gamma and the secreted levels were significantly increased compared with those in controls (P < 0.05), but interleukin 4 was not increased. CONCLUSIONS: An autoimmune mechanism against CA-II or LF, and Th1-type immune response, may be involved in AIP.
Adult↗
Stem cell factor and IL-6 do not promote complete maturation of human cultured mast cells from umbilical cord blood cells: an ultrastructural study.
Human mast cells are classified into two phenotypes based on their neutral protease compositions. One type is a tryptase-positive and chymase-positive MCTC cell that is predominant in the skin, another is a tryptase-positive and chymase-negative MCT cell that is predominant in the lung. Cord blood-derived human mast cells cultured in the presence of stem cell factor and interleukin-6 are a mixture of MCTC and MCT at various ratios, as revealed by immunocytochemical staining. We performed an electron microscopic analysis of cord blood-derived human cultured mast cells and found that they were so immature that we could not distinguish MCT and MCTC from their ultrastructural morphology. The response to secretagogues was not the response of MCTC but rather of MCT. Although human cultured mast cells are the most useful cells for use in in vitro experiments, the present culture condition supplemented with stem cell factor and interleukin-6 does not develop fully mature mast cells in vitro.
Cell Differentiation↗
Diurnal motor activities of the esophagus in conscious dogs.
Diurnal motor activities of the upper, middle, and lower thirds of the thoracic esophagus, the lower esophageal sphincter, and the gastric body were recorded in six conscious dogs, using extraluminal force transducers. The motor activities of the thoracic esophagus and the lower esophageal sphincter were divided into three major motility patterns: feeding, digestive, and interdigestive. Each motility pattern was basically composed of repetitive bursts of contractions that were clearly classified into type I and II according to their contractile properties. Type I bursts were peristaltic contractions initiated at the upper thoracic esophagus and sequentially propagated distally to include the sphincter. Propagation velocity and duration of type I contractions were similar in all three motility patterns, and these contractions never were propagated into the stomach. Type II bursts were nonperistaltic simultaneous contractions of the thoracic esophagus and lower sphincter appearing synchronously with phase III of gastric interdigestive migrating contractions. Amplitude and duration of type II contractions were maximal at the sphincter, suggesting initiation at that site. In nonfeeding patterns, type I contractions would clear the esophagus of refluxed gastric contents, while type II contractions would prevent reflux.
Animals↗
Diagnostic accuracy of a new non-invasive enzyme immunoassay for detecting Helicobacter pylori in stools after eradication therapy.
BACKGROUND: Helicobacter pylori eradication therapy has been commonly performed for patients with peptic ulcer. An inexpensive, reliable, non-invasive test would be useful for evaluation of the effectiveness of eradication therapy. AIM: To evaluate the diagnostic potential of a new non-invasive enzyme immunoassay (HpSA) for H. pylori antigen in stools. METHODS: A total of 112 peptic ulcer patients with H. pylori infection (82 male, 30 female; age range 22-81 years, mean 54 years) received a course of eradication therapy. Four weeks after the end of the therapy, stool samples were collected from all patients and tested using the HpSA. The diagnostic accuracy of the HpSA EIA was evaluated in comparison with the results of a 13C-urea breath test. RESULTS: The diagnostic sensitivity of HpSA EIA after eradication therapy was 90%, the specificity 98%, the positive predictive value 82% and the negative predictive value 99%. CONCLUSION: The HpSA stool test is potentially useful for the diagnosis of H. pylori infection 4 weeks after the end of eradication therapy.
Adult↗
Physical model-based indirect measurements of blood pressure and flow using a centrifugal pump.
This article describes a technique offering indirect measurements of pump pressure differential and flow with certain accuracy independent of changes in blood viscosity. This technique is based on noninvasive measurements of the motor current and rotation speed using the physical model equations of the centrifugal pump system. Blood viscosity included in the coefficients of the dynamic equations is first estimated, and then substitution of the estimated viscosity into the steady equations of the model provides pump flow and pressure differential. In vitro tests using a Capiox pump showed a sufficient linear correlation between actual values and their estimates for pressure differential and pump flow. An in vivo test using a 45 kg sheep showed that the proposed algorithm needs robustness for the convergence of estimates of viscosity. An overall evaluation, however, of the developed algorithm/model showed indications of success in terms of efficient computation and modeling.
Algorithms↗
Induction of follicular gastritis following postthymectomy autoimmune gastritis in Helicobacter pylori-infected BALB/c mice.
Helicobacter pylori is the major causative agent of chronic antral gastritis and is thought to be involved in the pathogenesis of mucosa-associated lymphoid tissue lymphoma (MALToma) developing in the human stomach. The aim of this study was to clarify whether corporal autoimmune gastritis (AIG), which is known to decrease acidity due to destruction of parietal cells, predisposes mice to H. pylori infection, thereby leading to MALToma-like pathology. BALB/c mice in which AIG had been induced by thymectomy 3 days after birth (AIG mice) were used. The AIG mice were orally administered mouse-adapted H. pylori at the age of 6 weeks and were examined histologically and serologically after 2 to 12 months. The results were compared with those obtained from uninfected AIG mice and infected normal mice. Germinal centers were induced in the corpus in 57% of the H. pylori-infected AIG mice, which elicited anti-H. pylori antibody responses in association with upregulation of interleukin-4 (IL-4) mRNA. In these mice, parietal cells remained in the corpus mucosa. These findings were in contrast to those with the uninfected AIG mice: fundic gland atrophy due to disappearance of parietal cells associated with upregulation of gamma interferon, but not IL-4, mRNA and no germinal center formation in the corpus. These observations suggest that AIG alters the infectivity of H. pylori, leading to MALToma-like follicular gastritis, at an early stage after H. pylori infection.
Animals↗
Renal artery lesions in patients with moyamoya disease: angiographic findings.
BACKGROUND AND PURPOSE: Renal artery lesions in moyamoya disease have been described sporadically in several case reports. The purpose of this study is to evaluate the angiographic findings of renal artery lesions in moyamoya disease and to determine the prevalence of renal artery lesions in patients with moyamoya disease. METHODS: Eighty-six consecutive patients with idiopathic moyamoya disease were prospectively examined with both cerebral angiography and abdominal aortography. The findings of abdominal aortography were reviewed for the presence and appearance of renal artery lesions and compared with the clinical data and cerebral angiographic findings. RESULTS: Of 86 patients with idiopathic moyamoya disease, 7 patients (8%) were found to have renal artery lesions. Six patients (7%) had stenosis in the renal artery, and 1 patient (1%) had a small saccular aneurysm in the renal artery. Two patients (2%) with a marked renal artery stenosis presented with renovascular hypertension, which resulted in an intraventricular hemorrhage in 1 patient. Furthermore, the renal artery stenosis in the 2 patients with renovascular hypertension was successfully treated with percutaneous transluminal angioplasty. There was no significant correlation between the presence of renal artery lesions and cerebral angiographic findings. CONCLUSIONS: Seven (8%) of 86 patients with moyamoya disease showed renal artery lesions, including 6 stenoses (7%) and 1 aneurysm (1%). Renal artery lesions are a clinically relevant systemic manifestation in patients with moyamoya disease.
Adolescent↗
Determination of alpha-tocopherol and alpha-tocopherylquinone in rat tissues and plasma by high-performance liquid chromatography with electrochemical detection.
Alpha-tocopherol and alpha-tocopherylquinone in rat tissues and plasma were determined simultaneously by using high-performance liquid chromatography-electrochemical detection (HPLC-ED) with dual electrodes in the series mode. Biological samples were saponified in the presence of a mixture of butylated hydroxytoluene, ascorbic acid, and pyrogallol and then extracted with hexane. The compounds were separated on a C18 column using a mobile phase containing 95% methanol and 0.05 M sodium perchlorate as the supporting electrolyte. After HPLC separation, alpha-tocopherylquinone was first reduced at an upstream electrode at -500 mV Both alpha-tocopherol and the reduction product of alpha-tocopherylquinone were then oxidized downstream at +600 mV. Only the downstream electrode current was monitored for the determination. Linearity of the standard curves was obtained over the range 5-30 pmol for alpha-tocopherol and alpha-tocopherylquinone. Minimum detectable quantities (S/N of 3) were 0.25 pmol for alpha-tocopherol and 0.31 pmol for alpha-tocopherylquinone. The method was applied to analysis of the contents of alpha-tocopherol and alpha-tocopherylquinone in rat tissues and plasma. By hyperoxia, the content of alpha-tocopherol was decreased remarkably in lung, and in contrast, the contents of alpha-tocopherylquinone were increased in all tissues studied with the exception of plasma, though the content of alpha-tocopherylquinone in normal rats is quite small. The technique is particularly useful in the quantitation of the oxidation of alpha-tocopherol in biological samples.
Animals↗
Scavengers for peroxynitrite: inhibition of tyrosine nitration and oxidation with tryptamine derivatives, alpha-lipoic acid and synthetic compounds.
The inhibitory effects of various endogenous and synthetic compounds on the nitration and oxidation of L-tyrosine by peroxynitrite were examined. Nitrating and oxidizing activities were monitored by the formation of 3-nitrotyrosine and dityrosine with a HPLC-UV-fluorescence detector system, respectively. Glutathione, serotonin and synthetic sulfur- and selenium-containing compounds inhibited both the nitration and oxidation reaction of L-tyrosine effectively. However, 5-methoxytryptamine, melatonin and alpha-lipoic acid only inhibited the nitration reaction, and enhanced the formation of an oxidation product. This is important evidence that there are different intermediates in the nitrating and oxidizing reactions of L-tyrosine by peroxynitrite. It was suggested that 5-methoxytryptamine, melatonin and alpha-lipoic acid reacted only with the nitrating intermediate of peroxynitrite and inhibited nitration of L-tyrosine. Actually, the DNA strand breakage, which is believed to be a typical reaction of hydroxyl radical-like species, caused by peroxynitrite was not effectively inhibited by 5-methoxytryptamine. 5-Methoxytryptamine, melatonin and alpha-lipoic acid were viewed as useful reagents for investigating the mechanisms of damage by peroxynitrite in vitro.
Antioxidants↗
Copper(II)-catalyzed oxidation of d-alpha-tocopherol by oxygen in aqueous solution.
alpha-Tocopherol (alpha-Toc) was solubilized in aqueous solutions using 13 solubilizing agents and the products of oxidation by oxygen in the presence and the absence of Cu(II) were analyzed by HPLC. In the presence of Cu(II), the oxidation was accelerated and 5-formyl-7,8-dimethyltocol and alpha-tocoquinone were the major oxidation products. Their yields greatly increased in the presence of Cu(II). The yields and the rates of formation of the products were dependent on the properties of solubilizing agents and other conditions as well as the presence of Cu(II) or other metal ions. It is suggested that slight changes in the structure of the solubilizing agents affect the course of the reaction.
Catalysis↗