Search PubMed⌕ Search

Biomedical subjects

H Ohno

Publications and source records attributed to H Ohno.

At least 631 records · Page 35Linked to original sources
PubMed1975

Inhibition of 6-methylsalicyclic acid synthesis by the antibiotic cerulenin.

Cerulenin, a specific inhibitor of beta-ketoacyl-(acyl carrier protein) synthetase [EC 2.3.1.41] and 3-hydroxy-3-methylglutaryl-CoA synthetase [EC 4.1.3.5], was studied to determine whether it inhibits 6-methylsalicylic acid synthesis, in which so-called "polyketide" formation, a condensation step similar to that in fatty acid synthesis, is involved. In fact, 100 mug/ml (4.5 X 10(-4) M) of cerulenin inhibited 60% of 6-methylsalicylic acid synthetase activity and 68% of fatty acid synthetase activity of Penicillium urticae.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMedDate not supplied

Malignant fibrous histiocytoma of the spleen: report of a case and literature review.

There is a marked paucity of reports on malignant fibrous histiocytoma (MFH) of the spleen in the literature, and there are no previous reports of its color Doppler sonographic (US) and contrast-enhanced US findings. We report on an 82-year-old male with splenic MFH (inflammatory subtype), with an emphasis on color Doppler and contrast-enhanced US findings.

Aged, 80 and over↗
PubMedDate not supplied

Strenuous endurance training in humans reduces oxidative stress following exhausting exercise.

The aim of this study was to evaluate whether high-intensity endurance training would alleviate exercise-induced oxidative stress. Nine untrained male subjects (aged 19-21 years) participated in a 12-week training programme, and performed an acute period of exhausting exercise on a cycle ergometer before and after training. The training programme consisted of running at 80% maximal exercise heart rate for 60 min.day-1, 5 days.week-1 for 12 weeks. Blood samples were collected at rest and immediately after exhausting exercise for measurements of indices of oxidative stress, and antioxidant enzyme activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT)] in the erythrocytes. Maximal oxygen uptake (VO2max) increased significantly (P < 0.001) after training, indicating an improvement in aerobic capacity. A period of exhausting exercise caused an increase (P < 0.01) in the ability to produce neutrophil superoxide anion (O2.-) both before and after endurance training, but the magnitude of the increase was smaller after training (P < 0.05). There was a significant increase in lipid peroxidation in the erythrocyte membrane, but not in oxidative protein, after exhausting exercise, however training attenuated this effect. At rest, SOD and GPX activities were increased after training. However, there was no evidence that exhausting exercise enhanced the levels of any antioxidant enzyme activity. The CAT activity was unchanged either by training or by exhausting exercise. These results indicate that high-intensity endurance training can elevate antioxidant enzyme activities in erythrocytes, and decrease neutrophil O2.- production in response to exhausting exercise. Furthermore, this up-regulation in antioxidant defences was accompanied by a reduction in exercise-induced lipid peroxidation in erythrocyte membrane.

Adult↗
PubMedDate not supplied

Calcitonin gene-related peptide increases in the dorsal root ganglia of adjuvant arthritic rat.

We examined the effect of adjuvant arthritis on the content of immunoreactive calcitonin gene-related peptide (iCGRP) in the dorsal root ganglia at L4-L6 levels and the spinal cord at a lumbar level in rats. Arthritis was induced by inoculating adjuvant into both hind-paws twice at a 10 day interval. In the arthritic rats 15 days after the first inoculation (day 15), the content of iCGRP was significantly increased in the dorsal root ganglia, with no change in the dorsal and ventral horns. The content in the dorsal root ganglia was still high on day 26 and had decreased by day 40. An intrathecal injection of colchicine (0.2 mg, 18 hr before killing) enhanced the increase of iCGRP in the dorsal root ganglia and decreased it in the dorsal horn of arthritic rats, although in noninoculated rats such treatment produced no significant changes in the content of iCGRP in both regions. The arthritis-induced increase in the content of iCGRP in the dorsal root ganglia was significantly reduced after treatment with the antiinflammatory analgesic, diclofenac sodium, in a dose of 3 mg/kg/day, PO for 10 days. Swelling and hyperalgesia in the hind-paw were depressed after such treatment. These results suggest that adjuvant arthritis with long-lasting inflammation with pain facilitates the turnover, especially biosynthesis, of CGRP in primary afferent neurons.

Animals↗
PubMedDate not supplied

Hyperactivity and spatial maze learning impairment of adult rats with temporary neonatal hypothyroidism.

Temporary hypothyroidism was induced in neonatal rats by 0.02% propylthiouracil (PTU) administration to lactating dams during days 0-19 after delivery, and its effects on the behavior and learning of their male offspring were examined. The serum T4 (thyroxine) level was returned to normal around 1 week after the last PTU administration, but the body weight gain was still depressed. The open field and Biel water maze tests at the age of 6 weeks showed an increased number of ambulations and an increase in errors with prolonged swimming time in the PTU rats. The radial arm maze test started at 13 weeks revealed that the PTU animals required more trials until they showed the first well-performed trial. The total number of choices was also larger, with less correct choices, and treatment effects on the response distribution and pattern were significant. Thus, the rats, which had suffered from temporary hypothyroidism in the neonatal period, showed hyperactivity and irreversible impairment in maze learning. These results suggest an involvement of temporary neonatal hypothyroidism in hippocampal dysfunction.

Animals↗
PubMedDate not supplied

Over-etching effects on micro-tensile bond strength and failure patterns for two dentin bonding systems.

OBJECTIVES: The purpose of this study was to determine (1) the weakest zone of resin-dentin bonds and (2) the relation between bond strength and failure mode to clarify the effect of demineralized dentin. METHODS: Human premolars were sectioned to expose the dentin surfaces, and the dentin surfaces were conditioned with phosphoric acid for 15, 60, 120, or 180s. Resin-dentin bonded specimens were produced using two adhesives: One-Step (Bisco) and OptiBond Solo (Kerr). Each sample was sectioned to produce a beam (adhesive area: 0.9mm(2)). Microtensile bond tests were then conducted, and the mean bond strengths (n=12 for each group) were statistically compared using two-way ANOVA and Duncan's multiple-range test (p<0.05). The fractured surfaces of all specimens were examined using SEM, and the areas of failure were measured using an image analyzer. RESULTS: For One-Step, the bond strength decreased with increase in acid-conditioning time (15s: 50.7+/-9.7, 60s: 40.8+/-11.0, 120s: 23.6+/-4.9 and 180s: 12.1+/-4.6MPa) (p<0.05). For OptiBond Solo, the bond strength in the case of 15s acid-conditioning time (42.6+/-7.9MPa) was significantly greater than that for the other times (60s: 31.9+/-10.3, 120s: 31.8+/-14.4 and 180s: 31.8+/-7.4MPa) (p<0.05). Fractography showed that the area percentage of the hybrid layer increased with increase in etching time for both systems. CONCLUSIONS: The integrity of the hybrid layer, especially the top part, has an effect on bond strength.

Acid Etching, Dental↗
PubMedDate not supplied

Learning/memory impairments in rat offspring prenatally exposed to phenytoin.

Phenytoin (PHT) was orally administered in dosages of 50 and 100 mg/kg/day to pregnant rats on days 7-18 of gestation. Offspring were tested on the negative geotaxis test, a figure-eight maze (F8), the Biel water maze (BM), the Morris maze (MM), and the radial maze (RM). In addition, a delayed nonmatching-to-sample (DNMTS) test was employed. The levels of neuropeptides in brain and brain weights were determined. The maturation of negative geotaxis was delayed in both PHT groups. PHT groups showed no differences in F8, BM, and MM. In the RM, the total number of choices was high, whereas the number of correct choices was low. In the DNMTS, PHT groups showed low for correct choices with a long interval. The concentrations of neuropeptides were changed in the mesolimbic cortex, hippocampus, and amygdala. Brain weights were lower at 6 weeks of age in the 100 mg/kg/day PHT group, but were comparable at 16 weeks of age. This study suggests that the RM is a detectable task for the learning/memory impairments induced by PHT. In addition, it is surmised that the learning deficit is due to a working memory impairment arising from abnormal changes in neuropeptides and an injury in the fetal hippocampus.

Animals↗
PubMedDate not supplied

Soft-tissue osteochondroma in the calcaneal pad: a case report.

Soft-tissue osteochondromas of the foot are infrequently occurring lesions. A 65-year-old woman presented with soft-tissue osteochondroma in the soft tissues superficial to the plantar aspect of the calcaneus. The mass was densely ossified without cortical destruction or other alteration in the adjacent calcaneal bone on x-rays and computed tomography images. A 99m Tc bone scan showed a focal area of an increased uptake at the site of the mass below the calcaneus. Magnetic resonance imaging demonstrated high signal mass on T1-weighted images, isointense to fatty marrow, adjacent to the thickened plantar aponeurosis. The mass was completely excised. Histologically, mature lamellar bone was seen centrally, and the periphery was capped with hyaline cartilage. Since the tumor was located in the plantar aponeurosis and comprised of a single nodule of well-developed bone with well-organized endochondral ossification, the pathogenesis of this lesion might be related to metaplasia.

Aged↗
PubMedDate not supplied

Redox reaction of poly(ethylene oxide)-modified hemoglobin in poly(ethylene oxide) oligomers at 120 degrees C.

Human hemoglobin, modified with poly(ethylene oxide) with average molecular weight of 3500 (PEO-Hb) was dissolved in PEO200 (molecular weight of 200) containing 0.5 M KCl. A quasi-reversible redox reaction of the PEO-Hb was found in PEO oligomers by alternatingly changing the potential polarity (+/- 1.2 V vs Ag). The PEO-Hb showed redox reactions in PEO200 even at 120 degrees C. PEO modification was concluded to give the thermal stability in some extent. In phosphate buffer at 70 degrees C, the electrochemical redox reaction of native Hb was not observed spectroscopically, but that of PEO-Hb was detected. The most effective factor was, however, concluded to be the use of PEO oligomers as a solvent. The molecular motion of PEO oligomers should be milder than that of water at higher temperature. This lower molecular motion was suggested to keep the redox activity of PEO-Hb in the PEO oligomer at 120 degrees C. However, the PEO-Hb in PEO200 was stable in the oxidized form at 30 degrees C; it was reduced without giving potential at 120 degrees C. Cyclic voltammetry revealed that this autoreduction was attributed to the shift of redox potential with elevating temperature.

Electrochemistry↗
PubMedDate not supplied

Effect of cast solvent on the electron transfer reaction for poly(ethylene oxide)-modified myoglobin on the electrode in poly(ethylene oxide) oligomers.

Myoglobin from horse skeletal muscle was modified with poly(ethylene oxide) (PEO) with an average molecular weight of 2000 or 5000. Myoglobin was soluble after this modification in several organic solvents and PEO oligomers. The electron transfer reactions of PEO-modified myoglobin cast on the indium tin oxide (ITO) glass electrode were investigated by cyclic voltammetry. The PEO-modified myoglobin, cast on the electrode from water or a methanol solution, showed quasi-reversible redox reactions in PEO (average MW of 400). On the other hand, no redox response was seen in PEO-modified myoglobin cast on it using chloroform or benzene as a casting solvent. A clear redox response of the PEO-modified myoglobin was observed after methanol treatment of these layers cast from chloroform or a benzene solution. This suggests that the conformational change of the adsorbed PEO-modified myoglobin layer on the ITO electrode cast from chloroform or a benzene solution was not irreversible. The cast condition of PEO-modified myoglobin on the ITO glass electrode was revealed to affect the electron transfer reaction for protein considerably in PEO oligomers.

Animals↗
PubMedDate not supplied

Induced thermostability of poly(ethylene oxide)-modified hemoglobin in glycols.

The thermostability and redox activity of poly(ethylene oxide) (PEO)-modified human hemoglobin in PEO200 (PEO containing KCl, average MW of 200, < 0.3% H2O) were investigated by UV-vis spectroscopy, by circular dichroism spectroscopy, and by cyclic voltammetry. Using PEO oligomers as a solvent, PEO-modified hemoglobin was reduced and oxidized at an indium tin oxide glass electrode in the temperature range of -10 to 120 degrees C. The thermostability of PEO-modified hemoglobin was affected by the molecular weight of the solvent PEO. In lower-molecular weight glycols (MW of < 150), PEO-modified hemoglobin was denatured within a few minutes at 80 degrees C. On the other hand, the absorbance at the Soret band for PEO-modified hemoglobin was unchanged for 2 h at 80 degrees C in PEO200. A decrease in the water content of solvent PEO200 also improved the thermostability of PEO-modified hemoglobin. Improvement in the thermostability was attributed to physicochemical characteristics such as the relatively low molecular motion of PEO oligomers used as a solvent.

Calorimetry, Differential Scanning↗
PubMedDate not supplied

Electric-field control of ferromagnetism.

It is often assumed that it is not possible to alter the properties of magnetic materials once they have been prepared and put into use. For example, although magnetic materials are used in information technology to store trillions of bits (in the form of magnetization directions established by applying external magnetic fields), the properties of the magnetic medium itself remain unchanged on magnetization reversal. The ability to externally control the properties of magnetic materials would be highly desirable from fundamental and technological viewpoints, particularly in view of recent developments in magnetoelectronics and spintronics. In semiconductors, the conductivity can be varied by applying an electric field, but the electrical manipulation of magnetism has proved elusive. Here we demonstrate electric-field control of ferromagnetism in a thin-film semiconducting alloy, using an insulating-gate field-effect transistor structure. By applying electric fields, we are able to vary isothermally and reversibly the transition temperature of hole-induced ferromagnetism.

Journal Article↗
PubMedDate not supplied

Muscle type-specific response of PGC-1 alpha and oxidative enzymes during voluntary wheel running in mouse skeletal muscle.

AIM: It is generally accepted that endurance exercise increases the expression of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha), which governs the expression of oxidative metabolic enzymes. A previous report demonstrated that the regulation of mitochondrial protein expression in skeletal muscles in response to cold exposure depends on muscle fibre type. Cold exposure and endurance exercise are both metabolic challenges that require adjustments in mitochondrial energy metabolism, we hypothesized that the exercise-induced increase in oxidative enzymes and PGC-1alpha expression is higher in fast-type than in slow-type muscle. METHODS: Female ICR mice were individually housed in cages equipped with running wheel for 1, 2, 4, 6 or 8 weeks. The soleus, plantaris (PLA) and tibialis anterior (TA) muscles were then prepared from each mouse. The expression levels of PGC-1alpha, mitochondrial proteins and GLUT4 were evaluated by Western blotting. RESULTS: The expression level of PGC-1alpha was increased only in the PLA muscle. Furthermore, the expression levels of all mitochondrial proteins and GLUT4 in the PLA muscle were increased. In the TA muscle, although there was no increase in PGC-1alpha expression, the expression levels of mitochondrial proteins and GLUT4 were increased. CONCLUSIONS: These results suggest that muscle type-specific responses occur during endurance exercise, and that the increase in PGC-1alpha expression is not the only factor that promotes oxidative capacity as a result of endurance exercise.

Animals↗