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Biomedical subjects

Shuji Adachi

Publications and source records attributed to Shuji Adachi.

12 recordsLinked to original sources
PubMed2003

Lipase-catalyzed condensation of p-methoxyphenethyl alcohol and carboxylic acids with different steric and electrical properties in acetonitrile.

The substrate selectivity of Candida antarctica lipase for various carboxylic acids was systematically investigated for their condensation with p-methoxyphenethyl alcohol in acetonitrile. The electron density of a carboxylic carbon and the projection area of an acid molecule were numerical indicators for evaluating the substrate selectivity. Both the electron density and projection area had an influence on the V/Km value, while only the projection area affected the Km value. The presence of conjugation with a carboxyl group in an acid and a branched structure in the non-carboxylic region independently lowered the V/Km value by an order of 1.

Acetonitriles↗
PubMed2003

Preparation of a water-in-oil-in-water (W/O/W) type microcapsules by a single-droplet-drying method and change in encapsulation efficiency of a hydrophilic substance during storage.

Microcapsules of a water-in-oil-in-water (W/O/W) emulsion, which contained a hydrophilic substance, 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA), in its inner aqueous phase, was prepared by hot-air-drying or freeze-drying the emulsion using a single-droplet-drying method. Pullulan, maltodextrin, or gum arabic was used as a wall material, and the oily phase was tricaprylin, oleic acid, olive oil, or a mixture of tricaprylin and olive oil. An encapsulation efficiency higher than 0.95 was reached except for the microcapsules prepared using gum arabic and oleic acid. The hot-air-dried microcapsules were generally more stable than the freeze-dried microcapsules at 37 degrees C and various relative humidities. The stability was higher for the microcapsules with tricaprylin as the oily phase than for the microcapsules with oleic acid. The higher stability of the microcapsules with tricaprylin would be ascribed to the lower partition coefficient of PTSA to the oily phase. There was a tendency for the stability to be higher at lower relative humidity for both the hot-air- and freeze-dried microcapsules. The volumetric fraction of olive oil in its mixture with tricaprylin did not significantly affect either the encapsulation efficiency or the stability of the hot-air-dried microcapsules.

Caprylates↗
PubMed2003

Purification of conjugated linoleic acid isomers through a process including lipase-catalyzed selective esterification.

A mixture of conjugated linoleic acids (CLAs) was prepared by alkali conjugation of high purity linoleic acid. The preparation contained 45.1 wt% cis-9, trans-11 (c9,t11)-CLA, 46.8 wt% trans-10, cis-12 (t10,c12)-CLA, and 5.3 wt% other CLAs. A process comprising Candida rugosa lipase-catalyzed selective esterification with lauryl alcohol, molecular distillation, and urea adduct fractionation under strict conditions in ethanol was very effective for purification of c9,t11- and t10,c12-CLAs. In particular, the urea adduct fractionation efficiently eliminated CLAs except c9,t11- and t10,c12-isomers. Purification of c9,t11- and t10,c12-CLAs from 1.0 kg of the CLA mixture increased the c9,t11-CLA purity to 93.1% with 34% recovery of the initial content, and increased the t10,c12-CLA purity to 95.3% with 31% recovery.

Candida↗
PubMed2003

[Diagnostic imaging--recent progress].

Current advances in the diagnostic imaging for lung cancer includes multidetector-row CT (MDCT), lung cancer screening using low-dose MDCT and fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. There is no question about the clinical usefulness of MDCT, and the further development of the hardware and the software of MDCT will open new horizons for CT diagnosis. PET is not an alternative modality to CT but a supplementary one, which adds metabolic information to the morphology. Recently, experimental research on the refraction imaging of human lung specimens has been performed with synchrotron radiation. With progressive refinement, this technique may come to have some practical purpose in diagnosing lung cancer in vivo.

Carcinoma, Squamous Cell↗
PubMed2002

Suppressive effect of saturated acyl L-ascorbate on the oxidation of linoleic acid encapsulated with maltodextrin or gum arabic by spray-drying.

6-O-Palmitoyl L-ascorbate was added to linoleic acid at various molar ratios of the ascorbate to the acid, the mixtures were emulsified with a maltodextrin or gum arabic solution, and the emulsions were spray-dried to produce microcapsules. At higher molar ratios, the oil droplets in the emulsions were smaller, and the oxidative stabilities of the encapsulated linoleic acid were higher for both the maltodextrin- and gum arabic-based microcapsules. 6-O-Capryloyl, caproyl, and lauroyl L-ascorbates, which were synthesized through lipase-catalyzed condensation in acetone, were also used for the microencapsulation of linoleic acid. Except for capryloyl L-ascorbate, the addition of a saturated acyl ascorbate, especially caproyl ascorbate, to linoleic acid was effective for preparing oil droplets of small particle diameter and for suppressing the oxidation of the encapsulated linoleic acid.

Acylation↗
PubMed2002

Contrast-enhanced MR perfusion imaging and MR angiography: utility for management of pulmonary arteriovenous malformations for embolotherapy.

OBJECTIVE: The purpose of this study was to assess the capability of MR perfusion imaging and angiography (MRA) for management of pulmonary arteriovenous malformation (PAVM). METHODS AND PATIENTS: Eight patients, having 15 PAVMs underwent pulmonary angiography (PAG), CT, MR perfusion imaging and MRA. For the pretherapeutic management, MRA was compared with PAG and CT regarding detectability and diameter of vasculature. For post-therapeutic management, the change in size of aneurysmal sac, any residual contrast-enhancement and the blood supply within the sac were evaluated. RESULTS: All PAVMs with aneurysmal sac, feeding artery and draining vein diameters of equal to or more than 3 mm, were identified and measured with similar results by all modalities. On follow-up studies, 7 (58.4%) out of 12 treated PAVMs showed a decrease in size and residual contrast-enhancement. The residual contrast-enhancement was considered as bronchial artery-to-pulmonary artery collateral flow by MR perfusion imaging. CONCLUSION: MR perfusion imaging and MRangiography are useful for management of PAVMs over 3 mm in diameter.

Adolescent↗
PubMed2002

Solitary pulmonary nodules: potential role of dynamic MR imaging in management initial experience.

PURPOSE: To evaluate the utility of dynamic magnetic resonance (MR) imaging in the management of solitary pulmonary nodules (SPNs). MATERIALS AND METHODS: Fifty-eight patients with 58 pathologic analysis-proved SPNs (diameter < 30 mm) underwent dynamic 1.5-T MR imaging. The 58 SPNs were classified into three groups at pathologic analysis: malignant SPNs (n = 38), active infections (n = 10), or benign SPNs (n = 10). From signal intensity-time curves generated after the bolus injection of contrast material, the maximum relative enhancement ratio and slope of enhancement were calculated and statistically compared among the three groups. Threshold values of these two dynamic MR indexes were determined on the basis of positive differentiations. RESULTS: The mean relative enhancement ratio and mean slope of enhancement for the malignant SPN group were significantly higher than those for the benign SPN group and significantly lower than those for the active infection group (P <.05). With 0.15 as the threshold maximum relative enhancement ratio for distinguishing the malignant SPN and active infection groups from the benign SPN group, the sensitivity, specificity, and accuracy were 100%, 70%, and 95%, respectively. With 0.025/sec as the threshold slope of enhancement, all SPNs with malignancy and active infection were clearly distinguished from benign SPNs. CONCLUSION: Dynamic MR indexes were useful in the differentiation between SPNs that necessitated further evaluation or treatment (malignancy and active infection) and SPNs that did not necessitate further evaluation or treatment (benign nodules).

Adolescent↗
PubMed2002

Solubility of saturated fatty acids in water at elevated temperatures.

The solubility in water of saturated fatty acids with even carbon numbers from 8 to 18 was measured in the temperature range of 60 to 230 degrees C and at a pressure of 5 or 15 MPa. The pressure had no significant effect on the solubility. The solubility of the fatty acids increased with increasing temperature. At temperatures higher than about 160 degrees C, the logarithm of the solubility in mole fraction was linearly related to the reciprocal of the absolute temperature for each fatty acid, indicating that the water containing solubilized fatty acid molecules formed a regular solution at the higher temperatures. The enthalpy of a solution of the fatty acids in water, which was evaluated from the linear relationship at the given temperatures, increased linearly with the carbon number of the fatty acid.

Fatty Acids↗
PubMed2002

Oxidation of linoleic acid encapsulated with soluble soybean polysaccharide by spray-drying.

Linoleic acid was encapsulated with a soluble soybean polysaccharide, gum arabic, or a mixture of both together with maltodextrin, and the oxidation process of the encapsulated acid was measured at 37 degrees C and at a relative humidity of 12%. The soybean polysaccharide was more effective for encapsulating the acid and suppressing the oxidation of the encapsulated acid than gum arabic. A mixture of the soybean polysaccharide and maltodextrin was also effective for this purpose when the weight fraction of the polysaccharide was equal to or greater than 0.75.

Antioxidants↗
PubMed2002

Kinetic expression for the oxidation of linoleic and arachidonic acid esters in their mixed system.

Two polyunsaturated fatty acids (PUFAs) or their esters were mixed, and their oxidation processes were measured at 65 degrees C and ca. 0% relative humidity. Except when a PUFA ester was mixed with a free PUFA, the oxidation of the less-oxidative PUFA was promoted as its content in the mixture decreased, while the oxidation of the more-oxidative PUFA was delayed with a decrease in its content. A kinetic model is proposed whereby a PUFA acts as the diluent for another PUFA, and the oxidation rate of the PUFA is proportional to the product of the unoxidized PUFA concentration and the sum of the concentrations of the oxidized PUFA and the other oxidized PUFA. This model well expressed the oxidation processes of the PUFAs in their mixed system.

Arachidonic Acid↗
PubMedDate not supplied

Prediction of the equilibrium conversion for the synthesis of acyl hexose through lipase-catalyzed condensation in water-miscible solvent in the presence of molecular sieve.

A method is proposed for predicting the equilibrium conversion for the synthesis of monoacyl hexose through the lipase-catalyzed condensation of a fatty acid and a hexose in a water-miscible solvent in the presence of a molecular sieve, based on the apparent reaction equilibrium constant, the adsorption isotherm of water on the molecular sieve, the solubility of hexose in the solvent, and the mass balance with respect of water. Validity of the model was examined for the syntheses of lauroyl mannose, lauroyl glucose, and myristoyl mannose in acetonitrile, 2-methyl-2-propanol, or 2-methyl-2-butanol with molecular sieves 3A 1/16 and 4A 1/16. The predicted conversions agreed well with the experimental values except for the case where a significant amount of diester was formed as the result of the addition of an excess amount of the molecular sieve to the solvent or the high molar ratio of the fatty acid to the hexose.

Acylation↗