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Biomedical subjects

M Yoshikawa

Publications and source records attributed to M Yoshikawa.

At least 163 records · Page 9Linked to original sources
PubMed2000

Bioactive saponins and glycosides. XVII. Inhibitory effect on gastric emptying and accelerating effect on gastrointestinal transit of tea saponins: structures of assamsaponins F, G, H, I, and J from the seeds and leaves of the tea plant.

Following the investigation of assamsaponins A, B, C, D, and E, four new saponins termed assamsaponins F, G, H, and I were isolated from the seeds of the tea plant (Camellia sinensis L. var. assamica PIERRE), while assamsaponin J was isolated from its leaves. The structures of assamsaponins F-J were elucidated on the basis of chemical and physicochemical evidence and found to be 16,22-O-diacetyl-21-O-angeloyltheasapogenol E 3-O-[beta-D-galactopyranosyl (1-->2)][beta-D-glucopyranosyl(1 -->2)- alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, 21-O-angeloyl-22-O-acetyltheasapogenol E 3-O-[beta-D-galactopyranosyl(1--> 2)][beta-D-glucopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]- beta-D-glucopyranosiduronic acid, 21-O-angeloyl-28-O-acetyltheasapogenol E 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-glucopyranosyl(1--> 2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, 21-O-tigloyl-28-O-acetyltheasapogenol E 3-O-[beta-D-galactopyranosyl(1--> 2)][beta-D-glucopyranosyl(1--> 2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, and 16,21-O-diacetyl-22-O-cinnamoyltheasapogenol B 3-O-[beta-D-galactopyranosyl(l-->2)][beta-D-rhamnopyranosy(1-->2)- alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, respectively. The saponin mixture from the seeds of the tea plant was found to exhibit an inhibitory effect on gastric emptying and an accelerating effect on gastrointestinal transit in mice. Theasaponin E1 the principle saponin of the tea plant, showed potent activity, while theasaponin E2 showed none, so that the position of the acyl groups in the sapogenin moiety is important from a pharmacological point of view.

Animals↗
PubMed2000

Medicinal flowers. II. Inhibitors of nitric oxide production and absolute stereostructures of five new germacrane-type sesquiterpenes, kikkanols D, D monoacetate, E, F, and F monoacetate from the flowers of Chrysanthemum indicum L.

The methanolic extract and ethyl acetate-soluble portion from the flowers of Chrysanthemum indicum L., Chrysanthemi Indici Flos, were found to show inhibitory activity against nitric oxide (NO) production in lipopolysaccharide-activated macrophages. Five new germacrane-type sesquiterpenes, kikkanols D, D monoacetate, E, F, and F monoacetate, were isolated from the ethyl acetate-soluble portion. Their absolute stereostructures were elucidated on the basis of chemical and physicochemical evidence, which included application of the modified Mosher's method. The effects of fifteen principal components from the ethyl acetate-soluble portion of this medicinal flower against NO production were examined and, among them, acetylenic compounds and flavonoids were found to show potent inhibitory activity.

Animals↗
PubMed2000

Saponins of plants of Panax species collected in Central Nepal, and their chemotaxonomical significance. III.

Panax pseudo-ginseng subsp. pseudo-ginseng has a carrot like root with a small rhizome. It was shown that the saponin composition of roots and rhizomes of this subspecies collected in Tibet and China was extremely poor. From the roots and rhizomes collected in Central Nepal, (specimen-PNct), only a small amount of an oleanolic acid saponin, beta-D-glucopyranosyl-oleanolate (2) was isolated together with a polyacetylene-alcohol, panaxynol (3). In another specimen (specimen-PNs), also collected in Central Nepal, two oleanolic acid saponins, stipleanoside R2 (4) and chikusetsusaponin IV (5) were detected. No dammarane saponin was identified in either specimen. P. pseudo-ginseng subsp. himalaicus (Subsp-H) has a big rhizome with a small round root. From rhizomes and roots of this subsp. collected in Central Nepal (specimen-HNct), a fairly large amount of dammarane saponins, ginsenosides-Rb1 (6), -Rd (7), -Re (9) and -Rg1 (10), gypenoside XVII (8), notoginsenoside-R1 (11), majonoside-R2 (12) and pseudo-ginsenoside-F11 (13) were isolated, while no oleanane saponin (oleanolic acid saponin) was identified in this subsp. Based on the present and previous studies, medicinal evaluation and chemogeographical correlation of Himalayan Panax spp. are discussed.

Chromatography, High Pressure Liquid↗
PubMed2000

Medicinal foodstuffs. XVII. Fenugreek seed. (3): structures of new furostanol-type steroid saponins, trigoneosides Xa, Xb, XIb, XIIa, XIIb, and XIIIa, from the seeds of Egyptian Trigonellafoenum-graecum L.

Six new furostanol-type steroid saponins called trigoneosides Xa, Xb, XIb, XIIa, XIIb, and XIIIa were isolated from the seeds of Egyptian Trigonella foenum-graecum L. (Leguminosae) together with six known furostanol-type steroid saponins: trigoneosides Ia, Ib, and Va, glycoside D, trigonelloside C, and compound C. The structures of trigoneosides Xa, Xb, Xlb, XIIa, Xllb, and XIIIa were determined on the basis of chemical and physicochemical evidence as 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furostane-2alpha+ ++,3beta,22xi,26-tetraol 3-O-alpha-L-rhamnopyranosyl(1-->2)-,beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-(25R)-5alpha-furostane-2 alpha,beta,22xi,26tetraol 3-O-alpha-L-rhamnopyranosyl(l -->2)-beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-(25R)-5alpha-furostane2alpha++ +,beta,22xi,26-tetraol 3-O-beta-D-xylopyranosyl(l -->4)-beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-(25S)-furost-4-ene-3beta,22xi,26- triol 3-O-Ca-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-(25R)-furost-4-ene-3beta,22xi+ ++,26-triol 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranoside, and 26-O-beta-D-glucopyranosyl(25S)-furost-5-ene-3beta,22xi,26-t riol 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranosyl (1-->3)-beta-D-glucopyranosyl(1--4)]-beta-D-glucopyranoside, respectively.

Carbohydrate Sequence↗
PubMed2000

Behavioral and pharmacological studies on gluten exorphin A5, a newly isolated bioactive food protein fragment, in mice.

Central effects of gluten exorphin A5 (Gly-Tyr-Tyr-Pro-Thr), a fragment from wheat gluten, were studied on the pain-inhibitory system, emotionality and learning/memory processes in mice. Orally administered gluten exorphin A5 produced neither an antinociceptive effect nor an effect on morphine analgesia. Intracerebroventricularly (i.c.v.) administered gluten exorphin A5 produced mild but significant antinociception in a dose-depepndent manner, while not affecting the morphine analgesia. On the other hand, oral gluten exorphin A5 suppressed the endogenous pain-inhibitory system, i.e., antinociception induced by socio-psychological- (PSY-) stress (SIA) using a communication box; intraperitoneal gluten exorphin A5 abolished both footshock- (FS-) stress-induced antinociception (SIA) and PSY-SIA; and i.c.v. gluten exorphin A5 suppressed FS-SIA, but rather potentiated PSY-SIA. This peptide given by these routes was without effect on forced swim-SIA. In addition, oral gluten exorphin A5 tended to prolong the retention time on open arms in the elevated plus-maze test. Finally, oral gluten exorphin A5 when given during the post-training period of learning/memory processes significantly increased the latency into the dark compartment in the one-trail step-though type passive avoidance test, indicating that the peptide also facilitates the acquire/consolidation process of learning/memory. Thus, gluten exorphin A5 has been found to produce various effects not only in the peripheral nervous systems but also in the central nervous system.

Analgesics, Opioid↗
PubMed2000

Introduction of enterostatin (VPDPR) and a related sequence into soybean proglycinin A1aB1b subunit by site-directed mutagenesis.

Enterostatin (VPDPR), having anoretic and hypocholesterolemic activities, and its homologue LPYPR, a hypocholesterolemic peptide found in the glycinin A5A4B3 subunit, were introduced into the corresponding site (TNGPQ) of the proglycinin A1aB1b subunit by site-directed mutagenesis. Modified proglycinins were expressed in E. coli and recovered from the insoluble fraction. VPDPR and LPYPR were released by the action of chymotrypsin and trypsin as expected. The overall yields of purified VPDPR and LPYPR were 40% and 62%, respectively.

Chymotrypsin↗
PubMed2000

Adjuvant and haemolytic activities of 47 saponins derived from medicinal and food plants.

Adjuvant and haemolytic activities of 47 saponins purified from medicinal and food plants were examined. The compounds showed various levels of both adjuvant and haemolytic activities. Soyasaponins and lablabosides showed strong adjuvant activity but little haemolytic activity. Jujubosides showed strong adjuvant and haemolytic activities. Escins showed weaker adjuvant activity than the adjuvant-control, but strong haemolytic activity. Comparison of the functional groups of each saponin revealed that the acyl residue in saponin, the aldehyde group at carbon 4 in aglycone, and branched sugar chains attached to aglycone, were not essential for adjuvant activity. Furthermore, saponins with an acyl residue or oxide-ring moiety tended to show haemolytic activity. These results suggest that the adjuvant activity of saponins does not relate with haemolytic activity. It is considered that not only the functional groups themselves, but the overall conformation harmoniously consisting of such functional groups, affects adjuvant activity of saponins.

Adjuvants, Immunologic↗
PubMed2000

A case of penetrating aortic atherosclerotic ulcer with hemoptysis.

A 69-year old Japanese woman with hypertension was admitted because of continuous back pain and recurrent hemoptysis. Radiographic findings showed an enhanced irregular mass, at the aortic arch fed by the tracheal artery, which implied both a penetrating aortic atherosclerotic ulcer and lung cancer. Diagnostic surgery revealed no evidence of cancer but did reveal a rupture of the intima at the distal part of the aortic arch. It is assumed that the transmural oozing occurred after development of the penetrating aortic ulcer, which formed an extra-aortic hematoma and caused surrounding inflammation, and led to tracheal artery feeding. The intramural hematoma might have weakened vascular wall tension from the aorta, and formed an oozing extra-aortic hematoma instead of an acute rupture.

Aged↗
PubMed2000

Microscopic polyangiitis that presented liver dysfunction prior to noted renal manifestations.

In microscopic polyangiitis (MPA), renal manifestations are very common as first symptoms. Here, we report a case of MPA which presented liver dysfunction prior to noted renal manifestations. A 58-year-old woman was hospitalized because of a fever for 8 weeks. A laboratory examination revealed marked elevation of alkaline phosphatase and gamma-glutamyl transpeptidase, while blood urea nitrogen and creatinine levels remained normal. Although apparent renal dysfunction developed in this case soon after hospitalization, physicians should be aware of the variety of clinical manifestations in MPA. Moreover, antineutrophil cytoplasmic autoantibodies were found to be helpful for diagnosing MPA.

Female↗
PubMed2000

Comparison of CT findings with resected specimens after chemoembolization with iodized oil for hepatocellular carcinoma.

OBJECTIVE: We assessed the role of dynamic CT in the evaluation of the efficacy of transarterial chemoembolization with iodized oil for hepatocellular carcinoma. MATERIALS AND METHODS: We examined 41 hepatocellular carcinoma lesions (mean diameter, 5.0 cm) in 40 patients (mean age, 60.6 years) who underwent transarterial injection of iodized oil alone (n = 3) or emulsion of iodized oil and doxorubicin hydrochloride (n = 10) followed by gelatin sponge particles (n = 27) and subsequent hepatectomy. On dynamic CT performed within 3 weeks before oily transarterial chemoembolization and within 4 weeks before surgery, we calculated the rate of necrosis on the basis of the assumption that the portion that retained iodized oil represented necrosis. We also calculated the reduction rate of the tumor. CT findings were compared with pathologic findings of resected specimens. RESULTS: Pathologic specimens and the necrosis rate measured on CT showed a good correlation (r = 0.83) when the portion of tumor that retained iodized oil was considered necrosis. No correlation existed if the portion that retained iodized oil was considered viable. We noted no significant correlation (r = 0.38) between the reduction rate of the tumor and necrosis rate. Also, we noted no correlation (r = 0.52) between the interval between transarterial oily chemoembolization and surgery and the reduction rate of the tumor. CONCLUSION: CT is suitable for the evaluation of the efficacy of oily chemoembolization for hepatocellular carcinoma on the basis of the assumption that the portion of tumor that retains iodized oil is necrotic. The rate of tumor size reduction measured on CT did not correlate with the therapeutic effect of chemoembolization.

Aged↗
PubMed2000

Accelerative effect of olive oil on adrenal corticosterone secretion in rats loaded with single or repetitive immersion-restraint stress.

The present study was performed to clarify the effects of dietary oils on physiological and metabolic changes induced by a stress, using one-time or repetitive water-immersion of restrained rats (single or repetitive stress) as an experimental stress load. In rats fed any test diets containing 20%) of the mixture of tripalmitin, tristearin, and corn oil (PSC), olive oil (OLI). safflower oil (SAF), and linseed oil (LIS) with repetitive stress loading, body weight gains and food intakes were generally reduced. The weights of the thymus and spleen also declined, but the adrenal weights were enhanced. Particularly, the increase in the adrenal weight of rats given the OLI diet was greater than of rats supplied with other diets. When the rats were loaded with the single or repetitive stress, the concentrations of urea, lipid peroxide, and corticosterone in the plasma were increased in rats fed any of dietary oils. The rise of plasma corticosterone level was especially great in rats fed the OLI diet. The concentrations of total cholesterol (T-CHOL) and triglyceride (TG) in the plasma and liver generally tended to be higher in rats fed the OLI diet than in rats given the other diets with and without stress exposure. Plasma corticosterone concentration was correlated to the adrenal weight (r=0.87, p<0.05). This study showed that OLI especially enhanced the adrenal weight in rats exposed to the repetitive stress and further raised the increased secretion of adrenal corticosterone in rats loaded with the single or repetitive stress compared with the other oils. The mechanism explaining these actions of OLI was inferred to be related to the levels of T-CHOL and TG in the plasma and liver generally enhanced by stress.

Adrenal Cortex↗
PubMed2000

Microsomal epoxide hydrolase genotypes and chronic obstructive pulmonary disease in Japanese.

Polymorphisms in the gene for microsomal epoxide hydrolase (mEPHX), an enzyme involved in the protective mechanism against oxidative stress, have been reported to be associated with individual susceptibility to the development of chronic obstructive pulmonary disease (COPD). The polymorphisms in exons 3 and 4 in the mEPHX gene were examined in a total of 358 Japanese individuals, including 40 patients with COPD and 71 patients with lung cancer. The overall frequencies of variant allele for mEPHX codons 113 (exon 3) and 139 (exon 4) were 44% and 14%, respectively. Moreover, a novel single nucleotide polymorphism (estimated allele frequency: 0.29) was identified in Japanese at 20 bp downstream of the codon 113 polymorphism with strong linkage disequilibrium with the wild allele for codon 113. While the frequencies of variant allele and proportions of individuals homozygous variant for codon 113, assumed having very slow mEPHX activity, were similar among COPD or lung cancer patients and the control population, they were significantly higher in patients with severe COPD than in those with mild COPD [P=0.0225, odds ratio 2.9 (95%CI 1.1-7.4); P=0.0350, respectively]. Thus, we found that the frequency of the variant allele for mEPHX codon 113 is higher in Japanese than that in Caucasians (P=0.0028), a novel silent polymorphism exists in exon 3 and shows strong linkage disequilibrium with the wild allele for codon 113, and individual homozygous variants for codon 113 may be associated with development of advanced COPD rather than the susceptibility to COPD.

Adult↗
PubMed2000

[The problem of a long-term follow up in patients with renal cell carcinoma].

PURPOSE: We investigated on a problem of long-term follow up in patients with renal cell carcinoma. PATIENTS AND METHODS: A total of 287 patients with renal cell carcinoma treated in Nara Medical University and affiliated facilities from January 1980 to December 1990 were examined. And we investigated the trend of explanation to patients including 287 patients from 1991 to 1995. RESULTS: Up to December 1995, there are 76 patients (26.5%) unable to be followed and 211 patients able to be followed. The former group patients were less declared cancer rather than the latter group patients. Of 76, 22 patients (28.9%) might misunderstand completely recovering from the cancer disease. For the recent 5 years, those patients who were declared cancer increased, and those patients who were explained benign disease decreased. CONCLUSION: These results suggested that declaration of cancer is important for patients with renal cell carcinoma to be followed for a long-term.

Aged↗
PubMed2000

Roles of endogenous prostaglandins and nitric oxide in inhibitions of gastric emptying and accelerations of gastrointestinal transit by escins Ia, Ib, IIa, and IIb in mice.

We reported previously that escins Ia, Ib, IIa, and IIb, isolated from horse chestnuts, inhibited the 30-min gastric emptying (GE) in mice. In this study, the effects of escins Ia-IIb on gastrointestinal transit (GIT), and the roles of endogenous prostaglandins (PGs) and nitric oxide (NO) in the effects of escins Ia--IIb on GE and GIT were investigated in fasted mice. Escins Ia-IIb (12.5-50 mg/kg, p.o.) dose-dependently accelerated GIT. Both GE inhibitions and GIT accelerations by escins Ia-IIb (25 mg/kg) were markedly attenuated by pretreatment with indomethacin (10 mg/kg, s.c., an inhibitor of PGs synthesis). Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.p., an inhibitor of constitutive and inducible NO synthase) attenuated the effects of escins Ia-IIb on GIT, but not on GE. The effect of L-NAME was reversed by L-arginine (600 mg/kg, i.p., a substrate of NO synthase), but not by D-arginine (900 mg/kg, i.p., the enantiomer of L-arginine). The GIT accelerations of escins Ia-IIb were not attenuated by pretreatment with D-NAME (10 mg/kg, i.p., the enantiomer of L-NAME) or dexamethasone (5 mg/kg, i.p., an inhibitor of inducible form of NO synthase). The results suggest that endogenous PGs play an important role in both GE inhibitions and GIT accelerations, and constitutive NO is involved in the GIT accelerations, by escins Ia--IIb in mice.

Animals↗
PubMed2000

Control system for an implantable rotary blood pump.

Rotary blood pumps can be used for long-term left ventricular assist devices. These pumps have several advantages over the conventional pulsatile pumps including smaller size, higher efficiency, and simple design and construction. However, one of the difficulties associated with the rotary blood pump is the proper control method to maintain an optimum flow rate in different physiological conditions. The rotary blood pump can be controlled by two methods. The first is to utilize the measured pump flow rate from its servo signal. The second is to detect and avoid abnormal pumping conditions such as; back flow and sudden increase in the pressure head. This abnormal situation typically occurs from excessive suction of blood when there is a functional or mechanical occlusion in the inflow cannula. The ultrasound flow meter is durable and reliable but it is difficult to continually monitor the blood flow rate of an implantable pump. Therefore, another method is needed instead of the continuous flow monitoring. One chronic calf having an LVAD was subjected for the development of this control system. This calf survived more than 6 months. Voltage, current, motor speed, heart rate and the pump flow rate were recorded and stored at 30-min intervals in a computer. Utilizing these parameters, attempts were made (1) to achieve indirect flow assessments and (2) to reveal abnormal operating parameters of the centrifugal pump (1). Indirect flow measurement, the predicted pump flow rate was calculated from these pump derived parameters (required power, motor speed and heart rate). The value of the coefficient of determination (R) between the measured and estimated pump flow rate was 0.796. (2) Abnormal operating indicator, there was an association between the required current and pump flow waves. The current was differentiated, and then calculated to the power of the differentiated current. The normal range of this value was 0.02+/-0.54. In abnormal conditions, this abnormal operating indicator increased 500 times. The predicted flow estimation method and abnormal operating indicator were available from intrinsic operating parameters of the pump and need no sensors. These two methods were simple, yet they are possibly effective and reliable servo control methods for a rotary blood pump.

Animals↗
PubMed2000

Development of a new silicone membrane oxygenator for ECMO.

Two types small and efficient ECMO oxygenators were developed utilizing the most up to date hollow fiber technology. Newly silicone hollow fibers possess sufficient mechanical strength while maintaining ultra thin walls of 50 micro meter. Two types of oxygenators were made with this fiber. The fiber length for the type 1 module is 150mm with a priming volume 194 cc (surface area 1.3 m(2)) and type 2 has a fiber length of 100 mm with a 144 cc priming volume (the surface area 0.8 m(2)). The studies were performed at 0.5, 1.0 and 2.0 L/min of blood flow and these oxygenators demonstrated. O(2) gas transfer rate of 69+/-4 ml/min/L for type 1 and 68+/-6 ml/min/L for type 2. The CO(2) gas transfer rate was 25+/-2 ml/min/L for type 1 and 32+/-2 ml/min/L for type 2. These results demonstrate type 2 oxygenator has similar gas exchange capabilities to those of Kolobows' oxygenator which has about 2.0 times larger surface area. Additionally, comparative hemolysis tests were preformed with this new oxygenator and the Kolbow. The NIH value was 0.006 (g/100 L) for the type 1 oxygenator and 0.01 (g/100 L) for the Kolbow oxygenator. These results suggested that this ECMO oxygenator had sufficient gas exchange performance in spite of being smaller and induced minimal blood damage.

Equipment Design↗