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Biomedical subjects

S Ohmori

Publications and source records attributed to S Ohmori.

At least 19 recordsLinked to original sources
PubMed2006

1-BP inhibits NF-kappaB activity and Bcl-xL expression in astrocytes in vitro and reduces Bcl-xL expression in the brains of rats in vivo.

1-Bromopropane (1-BP) has been widely used as a substitute for chlorofluorocarbon that destroys the ozone layer. Although the central neurotoxicity of 1-BP has been recently reported, a molecular mechanism is not clear. In particular, the effects on cells in brain have not been fully analyzed. Here, we studied the effects of 1-BP on the activation of transcription factors involved in anti-apoptotic function or cell survival in astrocytes. Astrocytoma cell lines, U251, U373 and VM, or murine primary astrocytes were used for in vitro assay. DNA binding activities of NF-kappaB in these cells induced by interleukin (IL)-1 or LPS were inhibited by 1-BP. Consequently, the treatment of U251 cells with 1-BP resulted in suppression of NF-kappaB reporter activity. Furthermore, 1-BP blocked IkappaBalpha degradation, which is important for NF-kappaB activation. In addition, the level of Bcl-xL mRNA, which is known as an anti-apoptotic gene, were reduced in U251 treated with 1-BP or in the brain from rat exposed to 1-BP (400 ppm, 12 weeks). These results suggest that subchronic inhalation exposure to 1-BP vapor may affect the Bcl-xL expression in astrocytes.

Animals↗
PubMed2004

Threonine metabolism in Japanese quail liver.

In general, threonine is metabolized by reaction catalyzed by threonine-3-dehydrogenase (TDH), threonine dehydratase (TH) or threonine aldolase (TA). The activities of these three enzymes were compared in the liver of Japanese quails and rats. The animals were fed a standard or threonine rich-diet, or fasted for 3 days. The specific activity of TDH in the liver from quail fed a standard diet was 11 times higher than that in the liver from rats fed a standard diet. The TDH activities in the livers of the fasting and 5% threonine-rich diet groups of quail were 3 and 2 times higher than those in the livers from quail fed the standard diet, respectively. The TH activity in the liver of rats fed a standard diet was 14 times higher than that in the liver of quail fed a standard diet. The TH activity in the rat liver after fasting was 2.3 times higher than that of the standard diet control. The activity of TA in the livers of rat and quail were so low that its role in threonine metabolism in both animals seemed to be negligible. These results suggest that threonine is a ketogenic amino acid in the quail liver, while it is a glucogenic in the rat liver.

Alcohol Oxidoreductases↗
PubMed2003

Threonine is the best substrate for D-lactate formation in octopus tentacle.

Carbon sources for D-lactate and enzyme activities related to D-lactate formation were investigated using cell-free homogenates of Octopus vulgaris tentacle tissue. The results are as follows: a) The best precursor for D-lactate formation was threonine and second best precursors were glycine and fructose-1,6-bisphosphate. Threonine and glycine served as precursors only in presence of glutathione. b) Both amino acids were precursors for methylglyoxal from which D-lactate was synthesized. Alanine, cysteine and serine were not precursors. We present a metabolic map for D-lactate formation in octopus in order to explain these experimental results.

Animals↗
PubMed2002

Spinal anesthesia hypotension in elective cesarean section in parturients wearing extra-strong compression stockings.

We have routinely applied an extra-strong graduated compression stocking to cesarean section patients to reduce the incidence of spinal anesthesia hypotension. Because bupivacaine has recently become available in Japan, we compared the incidence of spinal hypotension using either 2.0 ml of hyperbaric 0.3% dibucaine or 0.5% bupivacaine. There were 98 full-term parturients wearing the stocking who received 2.0 ml injection of dibucaine or bupivacaine for elective cesarean section. When systolic blood pressure decreased to 90-100 mm Hg or to less than 70% of the pre-anesthesia value, ephedrine was injected intravenously. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the dibucaine and bupivacaine groups. Although the demographic data and various data related to anesthesia or surgery were similar in the groups, the fluid volume and the dose and incidence of ephedrine injection during anesthesia showed significant differences: the mean dose was 3.6 and 1.5 mg and the incidence was 41% and 19% in the dibucaine and bupivacaine groups, respectively. Spinal anesthesia using bupivacaine results in a lower incidence of spinal hypotension compared with dibucaine and, in combination with fitting the extra-strong stockings onto both legs, is clinically useful for cesarean sections.

Adult↗
PubMed2002

Circulatory, respiratory and metabolic changes after thigh tourniquet release in combined epidural-propofol anaesthesia with preservation of spontaneous respiration.

Twelve elderly patients undergoing total knee arthroplasty received lumbar epidural anaesthesia and propofol infusion at 5 mg.kg(-1).h(-1) following a 1.5-2.0 mg.kg(-1) bolus dose with preservation of spontaneous respiration via a laryngeal mask airway. Circulatory, respiratory and metabolic variables were measured before and 1, 3, 5, 15 and 30 min after release of a pneumatic thigh tourniquet. The blood pressure was decreased at all time-points and the respiratory rate increased at 1 min. The P(a)CO(2) was increased only at 1 min. Arterial blood pH and base excess were decreased at 1 and 3 min and 1, 3 and 5 min, respectively. Arterial blood lactate levels were increased at all times. These characteristics were considered to be identical to those under regional anaesthesia with conscious spontaneous respiration, showing that spontaneous respiration under this anaesthetic regimen has a similar respiratory capacity to that of conscious spontaneous respiration.

Aged↗
PubMed2001

High-performance liquid chromatographic method to analyze picomole levels of glutathione, cysteine and cysteinylglycine and its application to pre-cancerous rat livers.

A HPLC-based method for quantifying glutathione, cysteine and cysteine-containing peptide is described. N-(2,4-Dinitrophenylaminoethyl)maleimide was synthesized from ethylenediamine, 2,4-dinitrochlorobenzene and maleic anhydride. The maleimide was reacted at 40 degrees C and pH 5.8 for 10 min with thiol compounds such as glutathione or cysteine. An aliquot of the reaction mixtures was applied to a reversed-phase column (4.6 x 150 mm) of HPLC. When glutathione and cysteine were simultaneously assayed, the column was eluted with a gradient of acetonitrile in potassium phosphate (pH 7.0). The derivatives were monitored at 350 nm. Good liner relationships existed between peak area and concentration of glutathione or cysteine from 10 pmol to 2 nmol. The recovery tests from rat liver homogenate were 99.7+/-2.2% for glutathione and 104.9+/-3.8% for cysteine. By this method gamma-glutamylcysteine, cysteinylglycine, and homocysteine could be also quantified. The determination limits of glutathione, cysteine and other thiol compounds were 5 pmol. The method is simple: a sample solution is mixed with the labelling reagent and an aliquot of the reaction mixture is applied to a standard HPLC. The hepatic levels of cysteine and glutathione in pre-cancerous rats were determined by this method. The cysteine level in pre-cancerous livers was extremely elevated in comparison to that of the control groups, while no difference was observed in the glutathione contents between the pre-cancerous and control groups.

Animals↗
PubMed2001

Tolerance to analgesia and dependence liability by topical application of dihydroetorphine to hairless rats.

The tolerance to analgesia and dependence liability of dihydroetorphine following topical application were investigated in hairless rats with and without formalin-induced inflammation. The analgesic effect of dihydroetorphine (s.c.) was 4600- to 7200-fold more potent than that of morphine. In non-inflamed rats, the analgesic effect of 24-h topical application of dihydroetorphine tape (35 microg) and 4-day repeated tape applications (20 microg/5 h/day) decreased with time after the start of application, even though the plasma dihydroetorphine concentrations did not decrease. In formalin-inflamed rats, however, the tolerance to analgesia diminished. Naloxone-precipitated weight loss was observed after 24-h infusion of dihydroetorphine but not after the tape application in non-inflamed rats. A significant rewarding effect was found in the non-inflamed rats conditioned by s.c. injection and tape application but not in the formalin-inflamed rats. These results indicate that topical application of dihydroetorphine has a tolerance and dependence liability when there is no pain, and therefore, it should be used only for pain relief.

Administration, Cutaneous↗
PubMed2001

Simultaneous determination of byak-angelicin and oxypeucedanin hydrate in rat plasma by column-switching high-performance liquid chromatography with ultraviolet detection.

A simple and sensitive column-switching HPLC method was developed for the simultaneous determination of two furocoumarin compounds, byak-angelicin and oxypeucedanin hydrate, which are the main components of hot water extract of Angelica dahurica root (AE), in rat plasma. Plasma sample was simply deproteinated with perchloric acid. After centrifugation, the supernatant was injected into a column-switching HPLC system consisting of a clean-up column (Symmetry Shield RP 8, 20x3.9 mm I.D.) and analytical column (Symmetry C18, 75x4.6 mm I.D.) which were connected with a six-port switching valve. The flow-rate of the mobile phase (acetonitrile-water, 20:80) was maintained at 1 ml/min. Detection was carried out at wavelength 260 nm with a UV detector. The column temperature was maintained at 40 degrees C. The calibration curves of byak-angelicin and oxypeucedanin hydrate were linear over the ranges 19.6 to 980 ng/ml (r2>0.997). The accuracy of these analytes was less than 4.4%. The intra- and inter-day relative standard deviations of byak-angelicin and oxypeucedanin hydrate were within 12.0% and 12.7%, respectively. The present method was applied for the analysis of plasma concentration from rats after administration of AE.

Animals↗
PubMed2001

High-performance liquid chromatographic analysis of the sulfation of 4-hydroxypropranolol enantiomers by monkey liver cytosol.

We developed a new high-performance liquid chromatographic method using an ODS column and a chiral column for the assay of racemic 4-OH-PL sulfate and enantiomeric 4-OH-PL sulfates, respectively. The method was successfully applied to measure phenolsulfotransferase (PST) activities for 4-OH-PL in cytosolic fractions from livers of Japanese monkeys (Macaca fuscata) and for comparison with its activity of cytosolic fractions from rat, rabbit, dog, and human livers and Hep G2 cells. The activity was ranked as Hep G2 cells > monkeys = humans = dogs = rats > rabbits. To evaluate the Japanese monkey as a nonhuman animal model in drug metabolism studies, we further characterized sulfation of 4-OH-PL as a further metabolic pathway in monkey livers to compare that with human livers. Inhibition studies in which cytosolic fractions were preincubated at 43 degrees C or 2,6-dichloro-4-nitrophenol (DCNP) used as a PST inhibitor indicated that two kinds of PSTs, thermolabile, low-Km and DCNP-resistant PST and thermostable, high-Km and DCNP-sensitive PST were involved in 4-OH-PL sulfation by monkey liver cytosol, which is very similar to the reported profile of 4-OH-PL sulfation by human liver cytosol. Sulfation kinetics in a low concentration range of 4-OH-PL enantiomers demonstrated that apparent Km values were similar between human and monkey liver cytosolic fractions, but the Vmax values were different, so that intrinsic clearance values (Vmax/Km, Clint) were higher in monkeys than in humans. Furthermore, enantiomer selectivity of [R(+)-4-OH-PL > S(-)-4-OH-PL] was observed in the Vmax and CLint values of monkey liver cytosol. These results indicate that the profile of sulfation of 4-OH-PL by liver cytosolic fractions is similar in humans and Japanese monkeys.

Adult↗
PubMed2001

Extra-strong graduated compression stocking reduces usage of vasopressor agents during spinal anesthesia for cesarean section.

Because a standard type of graduated compression stocking is not effective for the prevention of spinal anesthesia hypothension during cesarean section, we have used an extra-strong type of graduated compression stocking. This study examined whether the extra-strong stocking reduces usage of vasopressor agents. Forty-eight and 47 full term parturients were fitted with the standard stocking and the extra-strong stocking, respectively. Spinal anesthesia was performed by injecting 2.0 ml 0.3% dibucaine hyperbaric solution. When systolic blood pressure decreased to 90-100 mmHg or to less than 70% of the pre-anesthesia value, ephedrine was injected. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the groups. The mean dose of ephedrine injected during anesthesia was 12.2 and 4.3 mg, and the incidence of ephedrine injected was 85 and 49%, in the standard and extra-strong stocking groups, respectively. The extra-strong stocking group showed significantly lower values. Fitting the extra-strong stocking on both legs for cesarean sections undergoing spinal anesthesia reduced usage of vasopressor agents, suggesting a promising use of this stocking for non-invasive prophylaxis.

Adolescent↗
PubMed2001

Histological and functional analysis of vascular smooth muscle cells in a novel culture system with honeycomb-like structure.

Vascular smooth muscle cells (SMCs) undergo phenotype change with the development of atherosclerosis. The phenotype changes of SMCs have been observed in various culture conditions, such as collagen-coated dishes. Here, we report the morphological and functional features of SMCs in a novel culture system using type I-collagen in a characteristic three-dimensional structure designated as honeycombs. The number of ribosome and mitochondria in SMCs cultured in honeycombs was one half or third of those cultured on collagen-coated plastic plates. DNA and protein synthesis of SMCs cultured in honeycombs were less than 1 and 30-40%, respectively, of those cultured on plastic plates. In addition, PDGF-BB did not increase the amount of DNA synthesis in SMCs in honeycombs. SMCs in honeycombs were shown to express several proteins, which are known to express in SMCs in medial layers of arteries. Particularly, caldesmon heavy chain was expressed in SMCs cultured in honeycombs, whereas not in those on plastic plates. Although focal adhesion kinase (FAK) was clearly detected in SMCs in honeycomb, the phosphotyrosine content of focal adhesion kin ase decreased in the process of culture. Immunoblot analysis showed dear different expression of ERK1 and ERK2 of mitogen-activated protein kinase in SMCs. SMCs in honeycombs expressed ERK2, more abundantly compared to ERK1, whereas SMCs in plates show the same levels of expressions for both proteins. Thus, the histological and functional feature of SMCs in the novel culture system is different from SMCs in plastic plates. The three-dimensional culture system described here may be indicating that cultured SMCs are able to express different proteins responding to the surrounding structures.

Animals↗
PubMed2001

Intestinal first-pass metabolism of eperisone in the rat.

PURPOSE: The purpose of this study was to clarify quantitatively the contribution of the intestine to the first-pass metabolism of eperisone in rats. METHODS: The systemic availabilities of eperisone were estimated by administering the drug into the duodenum, portal vein, and femoral vein in rats in vivo. The first-pass metabolism of eperisone was confirmed in the perfused rat small intestine in situ. Metabolism of eperisone to an omega-1-hydroxylated metabolite (HMO), the first step of eperisone metabolism, was studied using rat intestinal microsomes in vitro. RESULTS: The bioavailabilities in the intestine were 0.176 and 0.0879 at administration rates of 100 and 25 mg/h/kg, respectively, whereas those in the liver were 0.532 and 0.486, respectively. In the intestinal perfusion experiment, the appearance clearance to the portal vein from the intestinal lumen was much lower than the elimination clearance from the intestinal lumen, resulting in high metabolic clearance of eperisone in the small intestine. Eperisone was biotransformed to HMO by rat intestinal microsomes, and this was inhibited by alpha-naphthoflavone and an anti-rat CYP1A antibody. CONCLUSIONS: Those data strongly suggest that eperisone may be metabolized to HMO by CYP1A in rat intestinal microsomes during the first-pass through the epithelium of the small intestine.

Algorithms↗
PubMed2001

High expression of CD34-positive sinusoidal endothelial cells is a risk factor for hepatocellular carcinoma in patients with HCV-associated chronic liver diseases.

CD34 has been widely used for the assessment of sinusoid-like neoangiogenesis in hepatocellular carcinoma (HCC). Recently, it was demonstrated that CD34-positive cells isolated from human peripheral blood differentiate into endothelial cells and contribute to neoangiogenesis in adults. We investigated the localization and the substantial role of CD34-positive endothelial cells in the liver with hepatitis C virus (HCV)--associated chronic liver diseases. Liver tissue sections obtained by biopsy from 56 patients with HCV-associated chronic liver diseases by were examined immunohistochemically using anti-CD34, anti-von Willebrand factor (vWF), and anti-vascular endothelial growth factor (VEGF) antibodies. CD34 was stained in the sinusoid, showing dotty, linear, semicircular, or circular patterns. However, sinusoidal expression of vWF was not substantially identified in the same specimens, indicating the existence of sinusoidal CD34-positive but vWF-negative endothelial cells. We classified these cells as CD34 LI and found that CD34 LI was correlated with the expression of VEGF. Among 34 patients with advanced-stage disease, the cumulative incidence of HCC was significantly higher in patients with CD34 LI >or= 12 (n = 16) than in those with CD34 LI < 12 (n = 18; P = .009). Moreover, among several clinicopathologic risk factors, CD34 LI could be recognized as an independently significant factor for development of HCC (relative risk, 7.36; P = .019). We conclude that CD34-positive endothelial cells are regulated by several factors, such as VEGF, and might play a substantial role in hepatocarcinogenesis. Furthermore, high expression of CD34-positive sinusoidal endothelial cells is a risk factor for HCC in patients with HCV-associated chronic liver diseases.

Adult↗
PubMed2001

Myocardial imaging with 123I-metaiodobenzylguanidine in essential hypertension and renovascular hypertension.

Iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging is considered to reflect cardiac sympathetic function. We performed myocardial MIBG scintigraphy and echocardiography in 27 patients with essential hypertension (EHT), 7 patients with renovascular hypertension (RVHT), and 8 normotensive subjects (NT) to investigate alterations in MIBG myocardial imaging in the presence of hypertension and left ventricular hypertrophy (LVH). EHT were divided into two groups based on LV wall thickness; EHT with LVH group (> or = 13 mm, n = 15) and EHT without LVH group (< 13 mm, n = 12). The delayed uptake of MIBG was decreased, and the washout rate of MIBG was greater in the EHT with LVH group than EHT without LVH group or NT group. The washout rate was correlated with LV mass and LV diastolic function (as assessed by mitral flow). In RVHT group, the MIBG washout rate increased even without LVH, compared with NT and EHT without LVH groups. In summary, the washout rate of MIBG increased in parallel with the development of LVH in EHT and increased independently of the LV mass in RVHT. Cardiac sympathetic function could be altered in hypertensive LVH and in renovascular hypertension.

3-Iodobenzylguanidine↗