Biomedical subjects

H Okuyama

Publications and source records attributed to H Okuyama.

At least 19 recordsLinked to original sources

PubMed1992

Both the anaerobic pathway and aerobic desaturation are involved in the synthesis of unsaturated fatty acids in Vibrio sp. strain ABE-1.

Vibrio sp. strain ABE-1 is a unique marine bacterium in terms of its ability to synthesize delta 9-trans-hexadecenoic acid and delta 7-cis-tetradecenoic acid (14:1(7c); Okuyama, H., Sasaki, S., Higashi, S. and Murata, N. (1990) J. Bacteriol. 172, 3515-3518). The present study, involving labeling with [1-14C]acetate, demonstrated that 14:1 is synthesized by the anaerobic pathway. When cells of this bacterium were grown in the presence of [1-14C]myristic acid (14:0), this compound was converted to palmitic (16:0) and hexadecenoic (16:1) acids but not to 14:1, under aerobic conditions. These results suggest that the incorporated 14:0 was elongated to 16:0 and then converted to 16:1 by the aerobic desaturation of 16:0. It appears that the anaerobic pathway and aerobic desaturation are both involved in the synthesis of unsaturated fatty acids during aerobic growth of Vibrio sp. strain ABE-1.

Acetates↗

PubMed1992

Synthesis in vitro of very long chain fatty acids in Vibrio sp. strain ABE-1.

The activity of fatty acid synthetase (FAS) from Vibrio sp. strain ABE-1 required the presence of acyl carrier protein and was completely inhibited by thiolactomycin, an inhibitor specific for a type II FAS. These observations indicate that this enzyme is a type II FAS. Analysis by gas-liquid chromatography of the reaction products synthesized in vitro from [2-14C]malonyl-CoA by the partially purified FAS revealed, in addition to 16- and 18-carbon fatty acids which are normal constituents of this bacterium, the presence of fatty acids with very long chains. These fatty acids were identified as saturated and mono-unsaturated fatty acids with 20 up to as many as 30 carbon atoms. The longest fatty acids normally found in this bacterium contain 18-carbon atoms. These results suggest that the FAS from Vibrio sp. strain ABE-1 has potentially the ability to synthesize fatty acids with very long chains.

Acyl Carrier Protein↗

PubMed1992

Intrapancreatic duodenal duplication associated with pancreatic pseudocysts.

A rare case of intrapancreatic duodenal duplication causing pancreatitis is reported. At 2 years of age, the patient presented with a recurrent pancreatic pseudocyst. Intraoperative pancreatogram showed the presence of cystic duodenal duplication in the aberrant lobe of the pancreas communication with the pancreatic duct. Since the resection of the duplication, she has been free from recurrence of pancreatitis. In this case, intraoperative pancreatography was of great value.

Duodenum↗

PubMed1992

Sonophoresis. II. Examination of the mechanism(s) of ultrasound-enhanced transdermal drug delivery.

We have shown previously that high-frequency ultrasound (sonophoresis) can significantly enhance the transdermal delivery of a topically applied drug in vivo and that the augmentation of transport was caused by the action of the ultrasound on the skin. However, these earlier experiments did not reveal (i) the mechanism of sonophoresis, (ii) the pathway of drug permeation under the influence of ultrasound, and (iii) any potentially detrimental effects of the enhancement procedure on skin structure and morphology. In the study reported here, these three key issues have been addressed using electron microscopy to follow the penetration of an electron-dense, colloidal tracer (lanthanum hydroxide; LH). Experiments have again been performed using the hairless guinea pig animal model. Colloidal LH suspensions were applied to skin sites, which were then immediately exposed to ultrasound (at 10 or 16 MHz) for 5 or 20 min. Passive transport of LH under identical conditions (but without ultrasound) provided the control measurements. Tissue processing after the treatment periods utilized standard electron microscopy staining procedures. We found the following: (1) LH does not permeate the skin by passive diffusion; under the influence of ultrasound, on the other hand, it penetrates through the stratum corneum (SC) and the underlying viable epidermal cell layers via an apparently intercellular route. (2) LH transports through the epidermis to the upper dermis, even after only 5 min of ultrasound treatment, a remarkable and unexpected finding.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗

PubMed1992

Sonophoresis. I. The use of high-frequency ultrasound to enhance transdermal drug delivery.

Previous attempts to use ultrasound (less than or equal to 1-MHz frequency and 1 to 3-W/cm2 intensity) to enhance transdermal drug delivery (so-called sonophoresis) have produced inconsistent results. Theoretical analysis of ultrasound propagation in tissue predicts that higher-frequency ultrasound (greater than 1 MHz) will increase the concentration of energy deposition in the stratum corneum (SC) (typically, the rate-limiting barrier to percutaneous penetration). This hypothesis was tested by comparing the passive transdermal delivery of salicylic acid with that under the influence of ultrasound at 2-, 10-, and 16-MHz frequency; measurements were performed in vivo in hairless guinea pigs. Total drug absorbed was quantified by determining the amount of salicylic acid (1) present in SC tape strips and (2) eliminated in urine. Sonophoresis for 20 min at 2 MHz caused no significant increase in salicylic acid delivery over passive diffusion; treatment with ultrasound at 10 and 16 MHz, on the other hand, significantly elevated salicylic acid transport, by 4-fold and 2.5-fold, respectively. Kinetic analysis of the sonophoretic data at 10 and 16 MHz also revealed that the diffusion lag time associated with transdermal drug delivery (TDD) was reduced. A shorter period (5 min) of sonophoresis again resulted in enhanced TDD (relative to the corresponding control) at the higher frequencies; the delivered dose, and the level of enhancement, however, were lower than those after the 20-min treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Composition and turnover of phospholipids and neutral lipids in human breast cancer and reference tissues.

The phospholipid (PL) content was 4-fold higher while the triacylglycerol (TG) content tended to be 65% lower in human breast cancer tissues as compared with non-cancerous reference parts from excised breast tissues. The variation in TG content among breast tissues was very large while that of PL was relatively small. The fatty acid compositions of PL were significantly different between the cancer and reference tissues; the proportions of octadecenoate (18:1), docosahexaenoate (22:6n-3), the total n-3 fatty acids and the n-3/n-6 ratio, but not the proportion of arachidonate (20:4n-6), were significantly higher in the major PL of cancer tissues as compared with those of the reference tissues. No significant differences were observed in the proportion of the major fatty acids of TG in these tissues. The turnover of lipids was faster in the cancer tissues than in the reference tissues. The turnover of TG was faster than that of PL in the cancer tissues, whereas the opposite was true in the reference tissues, indicating significant differences in lipid metabolism between these tissues. A striking difference in the n-3 and n-6 fatty acids of the reference tissues noted for Japanese and Finnish women is discussed in relation to the roles of eicosanoids and eicosanoid precursors in mammary carcinogenesis.

Adult↗

PubMed1992

Increase in potential activities of protein phosphatases PP1 and PP2A in lymphoid tissues of autoimmune MRL/MpJ-lpr/lpr mice.

The differential assay conditions for protein phosphatases PP1, PP2A, and PP2C were extensively studied by using crude extracts from mouse lymphoid tissues as enzyme sources. Under these conditions, the protein phosphatase activities were measured in MRL/MpJ-lpr/lpr mice (MRL/lpr mice), autoimmune-prone mice, and MRL/MpJ(-)+/+ mice (MRL/+/+ mice) and C3H/HeJ mice as the controls. In MRL/lpr mice, significant alterations in protein phosphatase activities from those in the control mice were demonstrated. In spleen and liver from MRL/lpr mice, potential activities of PP1 and PP2A were distinctly elevated over those of the control mice. These elevations appeared to be due to accumulation of the abnormal lymphocytes that emerged in MRL/lpr mice. Although the PP1 activity in MRL/lpr lymph nodes was lower than those of normal spleen and thymus, it was greatly increased by Co(2+)-trypsin treatment so that the PP1 activity of MRL/lpr lymph nodes was the highest among those of all the tissues examined. In contrast, PP2C activity showed no remarkable alteration in the autoimmune disease model mice as compared with that in the control mice. These results demonstrated a specific elevation in potency of protein dephosphorylation in the tissues of MRL/lpr mice, suggesting a new explanation for the defect in signal transduction in this disease.

Animals↗

PubMed1992

Lipid lowering effects of high linoleate and high alpha-linolenate diets in rats and mice. Consequence of long-term feedings.

Diets high in linoleate (safflower oil) or high in alpha-linolenate (perilla oil) were fed to rats for 11 months, and the effects of the diets on plasma and tissue lipids were compared. The plasma levels of total cholesterol (Cho), phospholipids (PL) and triacylglycerol (TG) were significantly lower in the high alpha-linolenate group than in the high linoleate group, the differences being more than 30% in the levels of total Cho and TG. The diets had differential effects on the lipid contents of major tissues: the TG level in muscle was higher but both the TG level in depot fat and the PL level in muscle were lower in the high alpha-linolenate group than in the high linoleate group. In order to clarify whether or not the hypolipidemic effect of the high alpha-linolenate diet was due to changes in the distribution of lipids among tissues, whole body lipids were estimated in mice fed these diets for 5 months. The whole body Cho content was significantly lower, by 28%, in the high alpha-linolenate group compared with the high linoleate group, but the total lipid content, PL and neutral lipids were similar between the groups. Our results indicate that the high alpha-linolenate diet has a more potent cholesterol lowering effect in plasma and body tissue than the high linoleate diet; interestingly, whole body TG levels are similar but tissue distributions of TG are different between the two dietary groups.

Animals↗

PubMed1992

Minimum requirements of n-3 and n-6 essential fatty acids for the function of the central nervous system and for the prevention of chronic disease.

General behavioral patterns of rats or mice fed 5 wt% safflower oil (75% linoleate [n-6] and less than 0.1% alpha-linolenate [n-3]) for two generations were significantly different from those of animals fed 5 wt% perilla oil (15% n-6 and 55% n-3). Also, brightness-discrimination learning ability and retinal function were higher in the perilla group than in the group fed 5 wt% soybean oil (53% n-6 and 4.7% n-3) or safflower oil, indicating that the requirement of n-3 for the maximum responses of the nervous system is above 0.6 en% when there is 6.8 en% linoleate n-6. Perilla oil has been found to be beneficial for the suppression of carcinogenesis, allergic hyperreactivity, thrombotic tendency, apoplexy, hypertension, and aging in animals, as compared with soybean oil and safflower oil. These results are against a lipid peroxide theory of aging, carcinogenesis, and chronic diseases. Animal experiments and epidemiological studies lead to a recommendation that the intake of n-6 should be decreased to as low as 2-4 en% and that of n-3 be increased to levels higher than linoleate n-6 for the prevention of chronic diseases prevailing in the industrialized countries.

Animals↗

PubMed1992

[Successful surgical treatment of coronary aneurysm following PTCA].

A case of 50-year-old man who developed coronary aneurysm at the initial PTCA site following dilatation was reported. The patient was suffered severe effort angina pectoris and admitted to our hospital. Coronary angiography revealed 99% stenosis in the right coronary artery (RCA), and the underwent balloon dilatation of the RCA lesion with 3.0 mm balloon catheter at 3 atm of pressure. PTCA provided sufficient coronary dilatation, however a small dissection remained. He was discharged from the hospital without any symptom. Two months after PTCA he was suffered from recurrent angina, and electrocardiographic exercise stress test was positive for ST segment depression in inferior wall. The repeat coronary angiography showed severe stenosis of the original lesion and aneurysm formation at the area of dissection which occurred during initial angioplasty. Coronary artery bypass surgery with a saphenous vein graft performed successfully.

Angioplasty, Balloon, Coronary↗

PubMed1991

Recombinant human granulocyte colony-stimulating factor inhibits the metastasis of hematogenous and non-hematogenous tumors in mice.

We studied the effects of in vivo administrations of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on the metastasis of murine hematogenous and non-hematogenous tumors in spontaneous and experimental metastasis models. Spontaneous lung metastasis caused by intra-footpad injections of B16-BL6 melanoma and Lewis-lung-carcinoma (3LL) cells were inhibited by intravenous (i.v.) and subcutaneous (s.c.) injections of rhG-CSF after excision of the primary tumors. Recombinant hG-CSF significantly inhibited liver metastasis when administered i.v. after i.v. injection of L5178Y-ML25 T-lymphoma cells. Multiple i.v. administration of rhG-CSF after the tumor inoculation prolonged the survival times of mice inoculated i.v. with L5178Y-ML25 lymphoma cells. Recombinant hG-CSF did not directly affect the growth of B16-BL6 and L5178Y-ML25 cells in vitro. During the administration periods, both i.v. and s.c. injections of rhG-CSF increased the number of total white blood cells (WBC) in peripheral blood to approximately 3 times the normal level in normal and tumor-bearing mice. We also found that the administration of rhG-CSF stimulates neutrophils to become cytostatic against these tumor cells. Our results indicate that the injection of rhG-CSF is effective in inhibiting lung and liver metastases by activating neutrophils and increasing cell number.

Animals↗

PubMed1991

Effect of dietary alpha-linolenate on platelet-activating factor production in rat peritoneal polymorphonuclear leukocytes.

The effects of dietary alpha-linolenate (18:3, n-3) and linoleate (18:2, n-6) on platelet-activating factor (PAF) production were examined. Rats were fed an alpha-linolenic acid-rich (perilla oil) diet or a linoleic acid-rich (safflower oil) diet for 6 wk, and polymorphonuclear leukocytes (PMN) were elicited by peritoneal injection of casein. The overall phospholipid content and composition as well as the subclass distribution of choline and ethanolamine glycerophospholipids in PMN were not altered by these diets. However, with the perilla oil diet their content of a putative precursor of PAF, 1-alkyl-2-arachidonoyl-sn-glycero-3-phosphocholine was approximately 50% of that with safflower oil diet. On exposure to various concentrations of FMLP, PAF formation by PMN in the perilla oil group was less than 50% of that by PMN in the safflower oil group. A larger difference in PAF productions by PMN in the two dietary groups was observed on their stimulation with calcium ionophore A23187. These results demonstrate that PAF production is modulated in some as yet unknown way by changing the alpha-linolenate/linoleate balance of the diet.

Animals↗

PubMed1991

The cis/trans isomerization of the double bond of a fatty acid as a strategy for adaptation to changes in ambient temperature in the psychrophilic bacterium, Vibrio sp. strain ABE-1.

The major phospholipid, phosphatidylethanolamine (PE), of Vibrio sp. strain ABE-1 contains a unique trans-unsaturated fatty acid, 9-trans-hexadecenoic acid (16:1(9t], at the sn-2 position of the glycerol moiety. The major molecular species of PE that contain 16:1(9t) at the sn-2 position have either 9-cis-hexadecenoic acid (16:1(9c] or hexadecanoic acid (16:0) at the sn-1 position. The transition temperatures of the liquid-crystal to the gel phase of 16:1(9c)/16:1(9t)-PE and 16:0/16:1(9t)-PE were -3 degrees C and 38 degrees C, respectively, temperatures that were 31 degrees C and 18 degrees C higher than the corresponding temperatures for 16:1(9c)/16:1(9c)-PE and 16:0/16:1(9c)-PE. The proportion of 16:1(9c)/16:1(9t)-PE and 16:0/16:1(9t)-PE increased significantly in cells grown at 20 degrees C over that in cells grown at 5 degrees C. When cells grown at 5 degrees C were incubated at 20 degrees C in the presence of cerulenin, an inhibitor of the synthesis de novo of fatty acids, the level of 16:1(9t) increased almost in parallel with a concomitant decrease in the level of 16:1(9c) at the sn-2 position. These results suggest that 16:1(9c) is converted to 16:1(9t) by the cis/trans isomerization of the double bond in the fatty acid. This conversion is discussed as a possible strategy for adaptation by bacteria to changes in temperature.

Adaptation, Physiological↗

PubMed1991

Effect of dietary alpha-linolenate/linoleate balance on endotoxin-induced hepatitis in mice.

Mice were fed diets with three different ratios of alpha-linolenate (18:3n-3) to linoleate (18:2n-6), and the severity of hepatitis during endotoxic shock was compared. Dietary enrichment with alpha-linolenate increased the severity of hepatitis and the mortality induced by lipopolysaccharide (LPS) in combination with D-galactosamine (GalN). Differences in the dietary alpha-linolenate/linoleate balance were mainly reflected in the levels of arachidonate and eicosapenatenoate in liver phospholipids. Pretreatment of mice with indomethacin was found to also enhance the severity of GalN/LPS-hepatitis. This indicated that cyclooxygenase products of arachidonate may suppress the development of GalN/LPS-hepatitis. The enhancement by high alpha-linolenate diets was not observed when a lethal dose of LPS in the absence of GalN was given. Our results indicate that there are pathophysiological conditions of endotoxin-induced hepatitis under which cyclooxygenase products of arachidonate play protective roles.

Animals↗

PubMed1991

Effect of dietary alpha-linolenate/linoleate balance on lipopolysaccharide-induced tumor necrosis factor production in mouse macrophages.

We examined the effect of dietary alpha-linolenate (18:3n-3)/linoleate (18:2n-6) balance on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production in mouse macrophages. Resident and casein-induced peritoneal macrophages from mice fed a high alpha-linolenate diet produced a higher amount of TNF than in the high linoleate diet group. However, TNF production was not affected by the dietary alpha-linolenate/linoleate balance when thioglycollate- and complete Freund's adjuvant-induced macrophages were stimulated with LPS. Serum TNF levels of mice intraperitoneally injected with LPS was also higher in the high alpha-linolenate group than in the high linoleate group. These diets affected the n-3/n-6 ratios of 20 and 22 carbon highly unsaturated fatty acids in macrophage lipids. Thus, the dietary enrichment with alpha-linolenate was found to enhance TNF production of macrophages isolated under limited conditions.

Animals↗

PubMed1991

Effects of a high-linoleate and a high-alpha-linolenate diet on the learning ability of aged rats. Evidence against an autoxidation-related lipid peroxide theory of aging.

This study examined the effect of dietary alpha-linolenate (18:3n-3)/linoleate (18:2n-6) balance on brain lipid compositions and brightness-discrimination learning ability in aged rats. An alpha-linolenate-rich diet with a peroxidizability index (PI) of 142 and a linoleate-rich diet with a PI value of 80 were used. Long-term feeding of these diets induced a significant difference in the n-3/n-6 ratios of highly unsaturated fatty acids in brain, but the PI values and the conjugated diene contents were similar between the two dietary groups. Rats fed the alpha-linolenate-rich diet had a longer mean survival time and an increased learning ability in senescence. These results contradict an autoxidation-related lipid peroxide theory of aging, and indicate that the aging process must also be considered in terms of n-3/n-6 balance of dietary fats.

Aging↗

PubMed1991

Recombinant fusion polypeptide with cell- and heparin-binding domains of fibronectin inhibits liver metastasis of L5178Y-ML25 lymphoma cells.

We have investigated the effect of recombinant polypeptides with cell-binding domain (C-274) or with heparin-binding domain (H-271) and their fusion polypeptide (CH-271) on liver metastasis of murine lymphoid tumor. The polypeptides containing heparin-binding domain, H-271 and CH-271, were able to inhibit liver metastasis when co-injected i.v. with L5178Y-ML25 T-lymphoma cells, while C-274 with cell-binding domain showed much weaker antimetastatic activity. Treatment with H-271 or CH-271 substantially prolonged the survival time of mice injected i.v. with L5178Y-ML25 cells. CH-271, containing cell- and heparin-binding domains, was more antimetastatic than H-271. The reason why CH-271 was more effective in inhibiting liver metastasis than H-271 can not be explained in terms of a difference in the stability in the circulation or in the molecular size of the polypeptide. The polypeptides used in this study did not affect the tumor cell growth or viability in vitro. CH-271 was found to be still active in inhibiting liver metastasis even when natural killer cells or macrophages were removed from this system. Furthermore, multiple administrations of CH-271 after tumor implantation effectively inhibited liver metastasis and enhanced the survival rate as compared with H-271, C-274 and untreated control. Thus, the fusion of H-271 with C-274 (i.e. CH-271) augments the antimetastatic property of H-271, possibly through the interaction between tumor cells and the heparin-binding domain of fibronectin.

2-Chloroadenosine↗

PubMed1991

Provirus integration at the 3' region of N-myc in cell lines established from thymic lymphomas spontaneously formed in AKR mice and a [(BALB/c x B6)F1----AKR] bone marrow chimera.

Among 18 thymic leukemia cell lines which have been established from spontaneous thymic lymphomas in AKR mice as well as in bone marrow chimeras which were constructed by transplanting allogeneic bone marrow cells into irradiated AKR mice, three proviral integration sites were identified; near c-myc, N-myc and pim-1 loci. No integration site specific for chimeric leukemia cell lines was found. In three thymic leukemia cell lines which contained rearranged N-myc genes, insertions of long terminal repeats (LTRs) of murine leukemia viruses were detected at 18 or 20 bp downstream of the translational termination codon. These results demonstrate that the 3' region of the N-myc gene is one of the integration targets for murine leukemia viruses in spontaneous thymic lymphomas. In these three cell lines, N-myc mRNA was stably transcribed and transcription of c-myc mRNA was down-regulated. The integrated murine leukemia viruses in AKR thymic leukemia were most likely AKV, though the DNA sequence of the LTR inserted in the genome of a leukemic cell line from [(BALB/c x B6)F1----AKR], CAK20, was different from LTRs of murine leukemia viruses so far reported.

Antigens, Surface↗