Biomedical subjects

K Higashiyama

Publications and source records attributed to K Higashiyama.

At least 19 recordsLinked to original sources

PubMed2006

Effects of amino acid on morphological development and nucleus formation of arachidonic acid-producing filamentous micro-organism, Mortierella alpina.

AIMS: Effects of amino acid on morphological development and nucleus formation of arachidonic acid-producing filamentous micro-organism, Mortierella alpina were investigated using flow-through chamber. METHODS AND RESULTS: Mortierella alpina CBS 754.68 was cultivated in flow through chamber using nutrient-rich, minimal and specific amino acid-containing minimal media. To investigate the effect of amino acid on morphological parameters either 0.28 g l(-1) alanine, 0.53 g l(-1) sodium glutamate one hydrate or 0.42 g l(-1) valine was added to the minimal medium. In a flow-through chamber, the growth of hyphal elements and nucleus formation of arachidonic acid-producing fungus M. alpina were studied on-line, using image analysis techniques. When the Ala- and Val-containing media were used, the hyphal growth units (HGUs) were 90.2 and 86.7 microm per tip, respectively, which were 2.4-fold higher than that in the nutrient-rich medium, indicating that Ala and Val stimulate the elongation of hyphae. The specific nucleus formation rates were Glu->Val-containing media>minimal and nutrient-rich media>Ala-containing medium. The nucleus doubling times in Glu- and Val-containing media were 1.9 and 2 h, respectively, which were not significant different. CONCLUSIONS: Ala and Val stimulate the elongation of M. alpina hyphae, and nucleus formation rates were Glu->Val->Ala-containing media. SIGNIFICANCE AND IMPACT OF THE STUDY: Formation of fungal morphology and nucleus were shown using the flow-through chamber coupled with image analysis, which making possible to discuss the relationship between mycelial morphology and nucleus formation of M. alpina.

Alanine↗

PubMed2002

Production of 5,8,11-eicosatrienoic acid by a delta5 and delta6 desaturation activity-enhanced mutant derived from a delta12 desaturation activity-defective mutant of Mortierella alpina 1S-4.

Enhanced production of 5,8,11-eicosatrienoic acid (Mead acid, 20:3omega9) was attained with a mutant fungus, Mortierella alpina JT-180, derived from delta12 desaturation activity-defective and delta6 desaturation activity-enhanced M. alpina M209-7. Production of 20:3omega9 by JT-180 was 1.4 times greater than that of the parent strain M209-7. This is thought to be due to its enhanced Delta5 desaturation activity, which was 3.3 times higher than that of M209-7. In both strains, 78.5-80.4% of the total lipids comprised triacylglycerol (TG), and 76.6-79.0% of 20:3omega9 was present in TG. Comparing the fatty acid compositions among various lipid species, the highest percentages (24.1-37.6%) of 20:3omega9 in total lipids were found in phosphatidylcholine. For optimization of 20:3omega9 production by JT-180, a glucose concentration of 4% in the culture medium and shifting of the growth temperature from 28 degrees C to 20 degrees C on the 2nd day were shown to be effective. Under optimal conditions, 20:3omega9 production by JT-180 reached 1.92 g/l culture medium in a 10-l jar fermentor (corresponding to 81.5 mg/g dry mycelia and 18.3% of total fatty acids), which is greater than that reported previously from M209-7 (1.65 g/l).

8,11,14-Eicosatrienoic Acid↗

PubMed2002

Monitoring of morphological development of the arachidonic-acid-producing filamentous microorganism Mortierella alpina.

Morphological parameters, such as hyphal growth rate, tip formation rate, tip extension rate and branch formation rate, of Mortierella alpina have been measured using a flow-through chamber under 25 different combinations of carbon and nitrogen concentrations. Morphological parameters were influenced not by C/N ratio but by carbon concentration in the medium. Specific rates of hyphal growth and tip formation both remained constant at a low carbon concentration of 5 g/l. Tip extension rate from one tip was 60 microm tip(-1) h(-1) at a carbon concentration below 15 g/l, and the branching formation rate was independent of carbon concentration. Tip extension rate was a function of specific hyphal growth rate, which in turn was linearly proportional to the specific tip formation rate, demonstrating that tip extension rate was exponentially proportional to the specific tip formation rate. Branch formation rate per hyphal element remained unchanged even at tip extension rates lower than 60 microm tip(-1) h(-1) and at specific hyphal growth rates lower than 0.83 h(-1), but decreased drastically at higher rates of tip extension and hyphal growth.

Arachidonic Acid↗

PubMed2001

Evaluation and structure-activity relationship of synthesized cyclohexanol derivatives on percutaneous absorption of ketoprofen using artificial neural network.

The effect of 35 newly synthesized O-ethylmenthol (MET) derivatives on percutaneous absorption of ketoprofen was investigated in rats. In order to understand the relationship between the structure of compounds and promoting activity (structure-activity relationship), an artificial neural network (ANN) was employed. In the in vivo percutaneous absorption study, male Wistar rats, weighing 160-180 g, were used. The apparent penetration rate (Rp) was estimated based on a pharmacokinetic model with a constant rate of penetration through the skin after a lag time. As an index of the promoting activity of each compound, an enhancement factor (Ef), defined as follows, was used: Ef=Rp(with enhancer)/Rp(without enhancer). An irritation evoked on rat skin was microscopically judged at the end of the in vivo percutaneous absorption experiment and evaluated as a total irritation score (TIS). Ef and TIS were selected as output variables to determine the ANN structure. Calculated logP, molecular weight, steric energy (SE), van der Waals area, van der Waals volume, dipole moment, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were used as factors to determine the structural nature of cyclohexanol derivatives. Among these parameters, logP, SE and LUMO significantly affected the prediction of Ef and TIS. The predicted values of Ef and TIS coincided well with in vivo percutaneous absorption experimental values. However, results observed with a linear regression method were poor compared with the ANN approach. The contribution index of logP was approximately 50% in the prediction of Ef, suggesting that lipophilicity among physicochemical properties contributes most of the promoting activity of these compounds.

Animals↗

PubMed2001

Simultaneous optimization based on artificial neural networks in ketoprofen hydrogel formula containing O-ethyl-3-butylcyclohexanol as percutaneous absorption enhancer.

The influence of the amounts of additives including 1-O-ethyl-3-n-butylcyclohexanol (OEBC), diisopropyl adipate (DIA), and isopropanol (IPA) on the penetration rate (R(p)) of ketoprofen from hydrogels through rat skin in vivo was investigated. Skin irritation evoked by the application of hydrogels was evaluated based on a microscopic observation of skin cross-sections. Both optimization techniques incorporating an artificial neural network (ANN) and a second-order polynomial regression analysis were applied to the optimization of ketoprofen hydrogel formulations. Findings indicated that the R(p) and total irritation score (TIS) of the skin were predicted quantitatively as a function of quantities of OEBC, DIA, and IPA, employing ANN. In contrast, the prediction ability of the polynomial regression equation was somewhat poorer compared with that of ANN. The observed results of R(p) and TIS in the optimal formulation coincided well with the predictions in the simultaneous optimization technique incorporating ANN.

Animals↗

PubMed2001

Mycelial pellet intrastructure and visualization of mycelia and intracellular lipid in a culture of Mortierella alpina.

The intrastructure of mycelial pellets of Mortierella alpina, which accumulate fatty acids in mycelia, was visualized following labeling with fluorescein isothiocyanate (FITC) and Nile red using fluorescence microscopy. The pellet was an ellipse shape, but its intrastructure was shaped as a doughnut with a cave inside. Using three-dimensional image analysis, it was shown that the lipid was produced on the edge of the pellet, which corresponded to the area where the mycelial density was high. The cavity ratio of the pellet section was determined on the basis of the FITC fluorescence intensity, and in the early culture stage remained at 0.2 in a 10-kl fermentor culture, but finally increased to 0.35. Mycelial pellet volume paralleled the cavity ratio. Application of the technique used here allows analysis of the intrastructure of fungal pellets and new types of fungal biological study.

Lipids↗

PubMed2001

Promoting mechanism of menthol derivative, 1-O-ethyl-3-buthylcyclohexanol, on the percutaneous absorption of ketoprofen.

Menthol derivatives were synthesized and evaluated for their promoting activity on the percutaneous absorption of ketoprofen and skin irritation in vivo, choosing O-ethylmenthol (MET) as the mother compound. The compound having a C-3 positionned n-butyl group (1-O-ethyl-3-n-buthylcyclohexanol, OEBC) indicated the most promoting activity and caused relatively little skin irritation. In order to understand enhancement mechanism of OEBC an in vitro permeation study of ketoprofen was performed. The time course of the cumulative amounts of drug permeated through the rat skin exhibited a linear relation after an initial lag time. This was analyzed in membrane diffusion model and the diffusion and partition parameters of ketoprofen were estimated. Both parameters were remarkably enhanced when a hydrogel containing a small quantity of OEBC (0.5%) was applied. Furthermore, to clarify the site of action of OEBC, we also investigated in vitro permeation study of ketoprofen employing different skins of state, reversed skin and stratum corneum stripped skin. When OEBC was added to the hydrogels which were applied to the reversed and stripped skins, almost no changes of the flux were observed compared with the control (without OEBC). These results suggested that the site of action of OEBC was stratum corneum. Morphological changes of the stratum corneum surface were microscopically observed with 0-2% OEBC. The spaces between the stratum corneum cells treated with 0.5-2% OEBC became extended and the shape of each cell became clear. This may suggest that the site of action of OEBC was the intercellular of stratum corneum. Furthermore, an electron spin resonance study was performed to investigate the effect of OEBC on the intercellular lipid bilayer fluidity of the stratum corneum and the rotational correlation times were calculated. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) were used as the spin label. In use of OEBC, the fluidity of TEMPO labeled the stratum corneum lipid increased as the addition of OEBC. The results suggested that OEBC promote the penetration of drugs by enhancing fluidity of the local lipid bilayers around TEMPO.

Algorithms↗

PubMed2001

Study on glutathionesulphonic acid as biodistribution promoter: concomitant use effect on verapamil hydrochloride and tegafur.

The effect of glutathionesulphonic acid (N-(N-gamma-L-glutamyl-L-beta-sulphoalanylglycine, GSO3H), which is one of the minor metabolites of glutathione (GSH), on the pharmacokinetics of verapamil hydrochloride (verapamil x HCl) and tegafur was investigated in rats. GSO3H was concomitantly used as sodium salt (GSO3Na). No significant change by the concomitant use of GSO3Na was recognized in the pharmacokinetics parameters of verapamil x HCl and tegafur, and plasma elimination of both substances was not affected by GSO3Na. The tissue-to-plasma concentration ratio (Kp) of verapamil x HCl in the lung 5 min after its administration under concomitant use of GSO3Na rose significantly, however, this effect disappeared 120 min after administration. No significant change was recognized in other organs. On the other hand, a significant difference of Kp of tegafur under a steady state concentration of GSO3Na was not recognized in any organs. It seemed that the elevation of a lipid solubility (oil water partition coefficient) of verapamil x HCl by the concomitant use of GSO3Na was related to the increase of the Kp value of verapamil x HCl in the lung. The partition coefficient of GSO3Na itself decreased when it was used concomitantly with verapamil x HCl.

Animals↗

PubMed2001

Effect of consumed carbon to nitrogen ratio of mycelial morphology and arachidonic acid production in cultures of Mortierella alpina.

The influence of the consumed carbon to nitrogen (C/N) ratio on arachidonic acid (AA) production and mycelial morphology was investigated in cultures of Mortierella alpina using shake flasks and a fermentor. The consumed C/N ratio was varied from 5 to 32 under the condition that the total initial amount of carbon and nitrogen sources was 50 g/l. Cellular yield increased markedly at C/N ratios below 7; carbon utilization was switched from cellular growth to lipid biosynthesis in the C/N ratio range of 7-15; lipid biosynthesis was most active when the C/N ratio was in the range of 15-32. However, for C/N ratios higher than 15, the mycelial concentration decreased due to nitrogen limitation but the lipid yield still increased. In the presence of excess nitrogen, the biomass concentration depended on the amount of the nitrogen source, but the AA yield was inversely related to this. On the other hand, in the presence of excess carbon, the fatty acid concentration increased with carbon source concentration but the AA concentration remained constant. From the viewpoint of AA production, the optimum C/N ratio was in the range of 15 to 20 with a balance between the amounts of carbon and nitrogen sources. When an enriched medium was used at a fixed C/N ratio of 20, the cellular and AA concentrations were shown to be proportional to the total concentrations of carbon and nitrogen sources in both flasks and the fermentor. The whole pellet size and width of pellet annular regions did not change with increasing C/N ratio for C/N ratios below 20 in the flask cultures. However, when the C/N ratio was higher than 20, these sizes increased in proportion to the C/N ratio.

Journal Article↗

PubMed2000

Effect of synthesized cyclohexanol derivatives using L-menthol as a lead compound on the percutaneous absorption of ketoprofen.

L-Menthol was selected as a lead compound to synthesize new candidates for percutaneous absorption enhancers. In a previous study, O-ethylmenthol (MET) was the most effective compound and caused relatively little skin irritation. To develop more effective compounds, mono- or disubstitute groups of cyclohexane with an O-ethyl group were synthesized. Some 35 compounds were synthesized and evaluated for their promoting activity and effect on skin. An in vivo percutaneous absorption study was performed using rats with hydrogel containing ketoprofen and each of the synthesized compounds. The plasma concentration of ketoprofen was determined after the application of hydrogel to the abdominal area of rats. The apparent penetration rate (R(p)) was estimated based on the pharmacokinetic model with a constant rate of penetration through the skin after the lag time. The 2-compartment model was applied to the data obtained from the iv administration. As an index to evaluate the promoting activity of each enhancer, an enhancement factor (E(f)) was defined as follows: E(f) = R(p) (with enhancer)/R(p) (without enhancer). Irritation to skin was pathologically evaluated. The treated area of rat abdominal skin was excised after the in vivo experiment using total irritation score (TIS). The compound having a C-3 positioned iso-butyl group on the chemical structure was the most effective and caused relatively little irritation among mono-substituted compounds. In the case of di-substituted compounds, all had the same effect as or a stronger effect than MET. Furthermore, the promoting activity almost corresponded to irritation. To estimate log P, one of the physicochemical properties of molecules, a computer program 'CAChe' was employed. The log P was calculated using the atom typing scheme. Multiple regression analysis revealed that the relations between E(f) or TIS and log P were parabolic. It was suggested that the optimum logP value reflects the promoting activity to enhance percutaneous absorption of ketoprofen.

Animals↗

PubMed2000

The hypoglycemic effect of (7R,9aS)-7-phenyl-octahydroquinolizin-2-one in mice.

(-)-Multiflorine (1), which was isolated from leguminous plants, produced a hypoglycemic effect when administered to mice with streptozotocin-induced diabetes. (-)-Multiflorine has an enaminone type conjugation on the A-ring, which is unusual in lupine alkaloids. Proceeding on the assumption that the A-B ring is responsible for the activity, several compounds bearing quinolizidin-2-one were synthesized and their hypoglycemic effects were examined. The hypoglycemic effect of (7R*,9aS*)-7-phenyl-octahydroquinolizin-2-one was approximately 4 times stronger than that of (-)-multiflorine measured by oral glucose tolerance test in normal mice. This result indicates that compounds possessing the quinolizidin-2-one ring system as the basic structure may be possible lead compounds for a new type of diabetes drug.

Alkaloids↗

PubMed2000

Lupin alkaloids from Chinese Maackia amurensis.

Two new alkaloids were isolated together with 16 known lupin alkaloids from the leaves and stems of Chinese Maackia amurensis. Their structures were determined by spectroscopic methods to be (-)-6alpha-methoxylupanine and (-)-5alpha-(12-cytisinylmethyl)-6alpha-hydroxylupan ine and identified by comparison with synthetic samples. The structures of lupin alkaloids were also related to the geographical distributions of the Maackia plants.

Alkaloids↗

PubMed1999

Dielectric analysis for estimation of oil content in the mycelia of Mortierella alpina.

The dielectric behavior of the filamentous fungi Mortierella alpina SAM2104 and 1S-4, which produce polyunsaturated fatty acid enriched oil in the mycelia, was investigated. During the cultivation carried out in a 10-kL fermentor for 12-15 days, the relative permittivity and conductivity of the broth were measured in the frequency range of 100 kHz to 30 MHz. The dielectric parameters, i.e., the amplitude of dielectric relaxation (Deltaepsilon) and the characteristic frequency (f(c)), were obtained by fitting the Cole-Cole equation to the observed dielectric relaxation, and the conductivity of the medium (kappa(a)) was also measured. The value of Deltaepsilon gradually increased from the second day through the end of cultivation, suggesting that volume fraction of the cell increased with oil accumulation. The conductivity of the cytoplasm (kappa(i)) was calculated from the experimental values of f(c) and kappa(a), using a theoretical equation based on an ellipsoidal cell model. As a result, good correlation between the calculated kappa(i) and the oil content was obtained. These findings indicate that dielectric analysis enables us to estimate the oil content in the mycelia of oleaginous fungi and also provides a useful tool for monitoring cell growth and for controlling the cultivation process.

Bioreactors↗

PubMed1999

Effects of dissolved oxygen on the morphology of an arachidonic acid production by Mortierella alpina 1S-4.

Arachidonic acid (AA) production by Mortierella alpina 1S-4 was investigated using a 50-L fermentor. In order to optimize the dissolved oxygen (DO) concentration and to investigate the effect of DO on morphology, cultivation was carried out under constant DO at various levels in the range of 3-50 ppm. To maintain a DO concentration above 7 ppm, two methods, i.e., the oxygen-enrichment (OE) method (experimental range, 25-90% oxygen gas supplied) and the pressurization (PR) method (experimental range, 180-380 kPa headspace pressure), were used. As a result, the optimum DO concentration range was found to be 10-15 ppm. In this optimum DO concentration range, the AA yield was enhanced about 1.6-fold compared to that obtained at 7 ppm DO, and there was no difference in the AA productivity between the OE and PR methods. When the DO concentration was maintained at 20-50 ppm using the OE method, the morphology changed from filaments to pellets, and the AA yield decreased drastically because of stress due to the limited mass transfer through the pellet wall. When the DO concentration was maintained at 15-20 ppm using the PR method, the morphology did not change, and the AA yield decreased gradually.

Arachidonic Acid↗

PubMed1999

Image analysis of morphological change during arachidonic acid production by Mortierella alpina 1S-4.

The changes in mycelial morphology during arachidonic acid (AA) production by Mortierella alpina 1S-4 were investigated using an image analysis system. Cultivation was performed in a 10-kl fermentor, and the culture broth was separated into two fractions by sieving (0.5 mm aperture size): the filament fraction (F-fraction, <0.5 mm), and the pellet fraction (P-fraction, >0.5 mm). The effect of the mycelial morphology in each fraction on AA production was analyzed. As a result, a product distribution in the culture broth wherein the AA content in the mycelia of the P-fraction was observed to be higher than that in the mycelia of the F-fraction throughout the cultivation. Morphological analysis of the P-fraction revealed that the hairy pellets became smooth because the mycelia on the pellet surface were shaved off; some pellets were broken and reduced in size. The shaved-off mycelia from the hairy pellets surface moved into the F-fraction and aggregated there. From the above findings, it was likely that the low AA content in the F-fraction was due to mycelial damage during the cultivation. In addition, the morphology of the hairy pellets was found to contribute to an increase in the viscosity of culture broth.

Journal Article↗

PubMed1999

Effect of nitrogen source on mycelial morphology and arachidonic acid production in cultures of Mortierella alpina.

The effects of nitrogen source on arachidonic acid (AA) production and morphological changes during the culture of Mortierella alpina were investigated using an image analysis system. When yeast extract, gluten meal, or corn steep liquor was used, a circular pellet morphology was obtained. However, when Pharmamedia, fish meal, or soybean meal was used, M. alpina formed radial filamentous mycelia. The radial filamentous area in the case of soybean meal was 75% of the total mycelial area. In a jar fermentor culture, M. alpina morphology varied with the cultivation period: (i) at 0-6 h culture, the inoculated pellet-like mycelia were adapted to the new environment, (ii) at 6 h-1 d culture, filamentous mycelia grew exponentially which yielded a feather-like morphology, (iii) at 1-2 d culture, the filamentous mycelia became disentangled as a result of the mechanical agitation; consequently, the proportion of filamentous mycelia was increased, (iv) at 2-4 d culture, mycelia showed stationary growth, but the AA concentration increased rapidly, and (v) at 4-6 d culture, hyphae grew thick radially with the AA concentration continuing to increase gradually. In the case of the cultures with feather-like morphology obtained using soybean meal, the AA yield was 0.14 g/g dry cell weight, which was two times higher than that in cultures grown using yeast extract. These results suggest that the feather-like morphology of culture of M. alpina is suitable for AA production.

Journal Article↗

PubMed1999

kappa-Opioid receptor-mediated antinociceptive effects of stereoisomers and derivatives of (+)-matrine in mice.

The antinociceptive effects of seven matrine-type lupin alkaloids were examined using the acetic acid-induced abdominal contraction test (the writhing test) and the tail-flick test in mice. (+)-Allomatrine, the C-6 epimer of (+)-matrine, produced the antinociceptive effect at 1/3 potency of (+)-matrine or pentazocine. It was demonstrated that the antinociceptive effects of (+)-allomatrine were mediated through the activation of kappa-opioid receptors, while the antinociceptive effect of (+)-matrine was mediated by both mu- and kappa-opioid receptors. (-)-Sophoridine, the C-6 epimer of (+)-matrine, (+)-sophoranol, (-)-14 beta-hydroxymatrine and (+)-matrine N-oxide, which possess a hydrophilic group, and (-)-sophocarpine and (-)-sophoramine having a double bond(s) did not show significant antinociceptive activity.

Alkaloids↗

PubMed1999

Thiomenthol derivatives as novel percutaneous absorption enhancers.

Thiomenthol derivatives were synthesized and their promoting activity on the percutaneous absorption of ketoprofen from hydrogels was evaluated in rats. The apparent penetration rate (Rp) of ketoprofen absorbed from the hydrogel was estimated by the pharmacokinetic model derived under the assumption of a constant penetration rate through the skin after a lag time. As an index of promoting activity of thiomenthol derivatives, an enhancement factor (Ef) was defined as the ratio of the Rp value with enhancer to the value obtained with the control not containing enhancer. Skin irritancy evoked by these derivatives was investigated microscopically by using a cross-section of the excised skin onto which ketoprofen hydrogel was applied. Total irritation score (TIS) was estimated by summation of each irritation score in several parts of the skin. The physicochemical parameters of thiomenthol derivatives such as a partition coefficient (log P) and a steric energy were calculated and the quantitative relationships between these parameters and the Ef values or TIS values were investigated on the basis of multiple regression analysis. As a result, a parabolic relationship between log P and Ef was noted. A similar relationship was also observed in the case of TIS.

Administration, Cutaneous↗