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Y Kojima

Publications and source records attributed to Y Kojima.

At least 451 records · Page 25Linked to original sources
PubMed1985

Structural requirements of lipid A responsible for the functions: a study with chemically synthesized lipid A and its analogues.

To confirm the revised lipid A structure of Escherichia coli and to establish the structure responsible for its functions, biological activities of the synthetic compounds based on the presented structure of E. coli lipid A were investigated. Compound 506, 2-deoxy-6-O-(2-deoxy-2-[(R)-3-dodecanoyloxytetradecanoylamino]-3-O [(R)3-tetradecanoyloxytetradecanoyl]-beta-D-glucopyranosyl]-3-O-[(R) -3-hydroxytetradecanoyl]-2-[(R)-3-hydroxytetradecanoylamino]-alpha -D-glucopyranose 1,4'-bis(phosphate), exhibited activities identical to those of natural E. coli lipid A in eliciting Shwartzman reaction and tests on lethality, pyrogenicity, interferon- and tumor necrosis factor-inducing activities as well as in B-cell activating activity and Limulus amebocyte lysate gelating activity. With the exception of the Shwartzman reaction the monophosphorylated synthetic compounds at either the 1 or 4' position showed slightly lower activities than the compound with the bisphosphorylated compound (Compound 506). The compound without the phosphate group showed no or only very weak activities. The structural requirements for each activity (i.e. binding position and composition of fatty acids and presence of phosphate groups) are discussed taking into account the results of previous investigations.

Animals↗
PubMed1985

Biological activities of chemically synthesized partial structure analogues of lipid A.

Analogues of the nonreducing sugar part of lipid A were chemically synthesized and tested for biological activities such as Limulus amebocyte lysate gelation, interferon- and tumor necrosis factor-induction, lethal toxicity in galactosamine-sensitized mice, and pyrogenicity. A 4-O-monophosphorylglucosamine derivative possessing 2-N-3-tetradecanoyl-oxytetradecanoyl and 3-O-tetradecanoyl groups (GLA-27) exhibited all activities tested except for pyrogenicity. Alteration of the acyl substituents or dephosphorylation as well as acylation or phosphorylation of the 6-OH caused most activities of GLA-27 to diminish or disappear altogether. On the other hand, the biological activities expressed by GLA-27 were not significantly affected even when the glucosamine backbone was changed to 1-deoxy type, epimer type at C-3 (allose form), or 3-amino type. These results indicate that the acyl substituents and the phosphorylation positions rather than the backbone structures in these partial structure analogues of lipid A affect the expression of biological activities of endotoxin. The results also clearly indicate that some biological activities of endotoxin can be expressed separately from pyrogenicity.

Animals↗
PubMed1985

Experimental studies of transplantation and regeneration of endocrine pancreatic cells.

Replacement of destroyed B-cells with new "healthy" ones appears to be the most physiological approach to treatment of insulin-dependent (type 1) diabetes. This could be achieved either by transplantation of isolated islets or pancreatic segments or by stimulation of the replicatory activity in the islet cells surviving the acute toxic or infectious insult. The results of our experimental investigations indicate that adult, mature insulin-producing cells can replicate very actively when challenged with a proper stimulus, such as when implanted into obese-hyperglycaemic mice. The growth of transplanted islets is, however, dependent on the site of implantation. Thus, the subcapsular space of the kidney is more favourable than the spleen. Furthermore, immunosuppressive therapy may impair islet cell replicatory activity, as demonstrated in this study for Cyclosporin A. In a search for factors stimulating islet cell replication, we found that the hepatotoxic agent galactosamine enhanced this process as observed autoradiographically one week after the injection. This fits in with previous case reports demonstrating increased mitotic activity in islets of patients suffering from various acute liver diseases. Altogether this series of experiments demonstrates that islet cell replication is a more dynamic process than has hitherto been believed. Obviously many conditions influence this process so significantly that an impact on the diabetic state of the patients can well be expected.

Animals↗
PubMed1985

[Thrombosis of cortical vein: a case report].

A 39-year-old woman presented with disturbed consciousness, left hemiparesis and headache. CT scan revealed subcortical hemorrhage in the right parietal region, which had lower density than usual intracerebral hemorrhage and was associated with irregular perifocal edema. Cerebral angiograms revealed narrowed cortical vein with irregular wall in the right parietal region, where delayed local blood flow into the deep cerebral veins through collateral vessels was noted. The diagnosis was subcortical hemorrhage due to thrombosis of cortical vein. Her symptoms and brain edema were progressive. To reduce intracranial pressure, evacuation of the hematoma was performed. The hematoma which existed 1cm under the right parietal cortex was about 20g in weight. She remarkably improved soon after operation. Frequency of sinovenous thrombosis has been reported to be about 10% of all cerebral ischemic diseases, however, localized venous thrombosis is rare among them. This is because it is not always symptomatic and it is difficult to make accurate diagnosis. Six cases of localized venous thrombosis were reviewed, in which accurate diagnosis were established by cerebral angiograms, CT scan and/or autopsy. Clinical and radiological features of this case were presented.

Adult↗
PubMed1984

Biological activities of analogues of lipid A based chemically on the revised structural model. Comparison of mediator-inducing, immunomodulating and endotoxic activities.

Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities.

Adjuvants, Immunologic↗
PubMed1984

Biological activities of chemically synthesized analogues of the nonreducing sugar moiety of lipid A.

Biological activities of five synthetic lipid A analogues (D-glucosamine derivatives) were examined to elucidate the structure required for expression of the biological activities of endotoxin. Proclotting enzyme of horseshoe crab activation, interferon-inducing and tumor necrosis factor-inducing activities were significantly expressed by an analogue which possesses 4-O-phosphoryl, 3-O-tetradecanoyl and N-tetradecanoyloxytetradecanoyl groups. The results obtained with different analogues show that the 4-O-phosphoryl and N-tetradecanoyloxytetradecanoyl groups are important for expression of the above activities. The effect of 6-O-acylation in preventing the expression of these biological activities is also suggested. Pyrogenic activity was not detected in any of the compounds tested.

Animals↗
PubMed1984

Perfusion preservation of cadaver rat pancreas: I. Morphological observation and biological function of the islets.

When using methods of perfusion to preserve the rat pancreas, we found that perfusion into the celiac axis was the most effective. The viability of the cadaver pancreas from decapitated rats preserved by perfusion into the celiac axis for 6 hours under various conditions of hypothermia, hyperbaria and oxygenation was investigated. The condition of perfusion affected the ratio of degenerative islets/normal islets in the pancreas. The ratio, under conditions of hypothermia and oxygenation was the lowest, while that under conditions of hyperbaria was the highest. Insulin-releasing activity of islets from 6-hour-perfusion-pancreas, under conditions of hypothermia and oxygenation was 86.5 per cent or more of that of the control. Stainings with fluorescent antibody and peroxidase antiperoxidase, revealed a large number of A and B cells in the islets of the pancreas, in cases of up to 6 hours of perfusion.

Animals↗
PubMed1984

Perfusion preservation of cadaver rat pancreas: II. Culture after perfusion and successful transplantation.

We designed a new process for culturing pancreatic islets and applied this method to cultures of rat pancreatic islets which had degenerated during preservation by the perfusion-method for 6 hours under the condition of hypothermia and oxygenation. The objective was to determine the extent of the original function. Transplantation of these so-treated islets was also attempted. When pancreatic islets isolated from the pancreas after 6-hour-perfusion were cultured, morphological restoration was apparent within the first 3-4 days. Insulin contents of the culture media renewed every 3 days, ranged from 851 to 1,134 microU/ml/two islets during culture period of 21 days. In the glucose-loading test, insulin secretion of the islets was the same as that of islets in the control experiments. Transplantation of these islets into the portal vein of streptozotocin-induced diabetic rats resulted in a good recovery from the diabetic state.

Animals↗
PubMed1984

[Fundamental and clinical studies of sulbactam/cefoperazone in the pediatric field].

Fundamental and clinical studies were carried out on sulbactam/cefoperazone (SBT/CPZ) in the field of pediatrics. The following results were obtained: A total of 185 clinical isolates that had been stocked at our department was employed to determine the minimum inhibitory concentrations (MICs) of SBT/CPZ against various bacterial species. SBT/CPZ showed strong antibacterial potency against E. coli, Salmonella, Klebsiella and P. mirabilis, and relatively strong potency against S. marcescens, P. aeruginosa and S. aureus. Antibacterial potency of SBT/CPZ was stronger than that of CPZ alone against E. coli, and it also showed strong activity against strains of Salmonella, S. marcescens and S. aureus, moderately or highly resistant to CPZ. SBT/CPZ was administered by intravenous bolus infusion to pediatric patients to determine the serum concentrations of SBT and CPZ. At a dose of 10 mg/kg the mean serum levels of SBT and CPZ were as follows; 17.8 micrograms/ml, 40.7 micrograms/ml at 15 minutes and 0.3 microgram/ml at 6 hours, respectively. The half-lives of SBT and CPZ in the serum were 1.05 hours and 1.76 hours, respectively. Similarly, at a dose of 20 mg/kg the mean serum levels of SBT and CPZ were; 31.9 micrograms/ml, 81.0 micrograms/ml at 15 minutes and 0.5 microgram/ml, 6.1 micrograms/ml at 6 hours, and the half-lives were 1.00 hour and 1.72 hours, respectively. At a dose of 40 mg/kg, only 1 case was determined. The serum levels of SBT and CPZ were 34.4 micrograms/ml, 74.8 micrograms/ml at 30 minutes and 0.2 microgram/ml at 6 hours, and the half-lives were 0.78 hour and 1.38 hours, respectively. SBT/CPZ was drip-infused intravenously over a period of 1 hour, and the serum concentrations of SBT and CPZ were determined. At the dose of 10 mg/kg or 20 mg/kg, the peak serum levels of SBT and CPZ were observed at 1 hour or at the end of drip infusion. At a dose of 10 mg/kg the mean serum levels of SBT and CPZ were 14.4 micrograms/ml, 33.7 micrograms/ml at 1 hour and 1.4 micrograms/ml, 4.6 micrograms/ml at 7 hours, respectively. The half-lives was 1.86 hours for SBT and 2.23 hours for CPZ, respectively. Similarly at a dose of 20 mg/kg, the mean serum levels of SBT and CPZ were, 22.2 micrograms/ml, 34.6 micrograms/ml at 1 hour and 0.5 microgram/ml, 2.8 micrograms/ml at 7 hours, and the half-lives was 1.17 hours and 1.75 hours, respectively. The urinary recovery rate was determined for the 6 hours period after administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1984

Familial amyloidotic polyneuropathy: ocular manifestations with clinicopathological observation.

Clinical findings of ocular involvement in two patients with familial amyloidotic polyneuropathy are described. Both cases revealed irregular pupillary margin, white membranous material on the pupillary border and on the lens surface. Open-angle glaucoma was found in one case, and ocular hypertension in the other. Histopathological examination of the tissues obtained during trabeculectomy in Case 1 revealed a large amount of amyloid substance around the vessels of the conjunctiva and the iris and in the endothelial meshwork of the chamber angle. Electron microscopic observation revealed that amyloid fibrils had formed in the basement membrane of the endothelial cells of the blood vessels in the conjunctiva and the iris. However, no amyloid fibrils were observed in the endothelial cells of the trabecular meshwork. Crossed immunoelectrophoresis of the aqueous humor of Case 1 showed a high-protein content, especially of alpha 1-lipoprotein and ceruloplasmin. The findings described above suggest that glaucoma or ocular hypertension in association with familial amyloidotic polyneuropathy is a result of the accumulation of amyloid substance in the endothelial meshwork.

Adult↗
PubMed1984

Pharmacological properties of 2-[4-(2-thiazolyloxy)-phenyl]-propionic acid (480156-S), a new non-steroidal antiinflammatory agent.

In terms of antiinflammatory activity in acute and chronic animal models, 2-[4-(2-thiazolyloxy)-phenyl]-propionic acid (480156-S) was more active than ibuprofen but inferior to indomethacin. The analgesic activities of 480156-S measured by the writhing method and the Randall & Selitto method were comparable or superior to those of indomethacin, diclofenac-Na and ketoprofen. 480156-S also had strong antagonistic action against bradykinin, markedly inhibiting all bradykinin-induced edema and pain reactions (tail licking in mice and flexor reflex of rabbit hind limb). On scald-induced pain in which bradykinin is greatly involved, 480156-S had an obviously stronger analgesic effect than any of the reference drugs. As for its effects on prostaglandin (PG), 480156-S weakly inhibited arachidonic acid-induced edema and pain reactions but also inhibited PGE2 synthesis of bovine vesicular gland microsomes.

Animals↗
PubMed1983

Interferon-inducing, pyrogenic and proclotting enzyme of horseshoe crab activation activities of chemically synthesized lipid A analogues.

Interferon-inducing, pyrogenic and proclotting enzyme of horseshoe crab activation activities of chemically synthesized lipid A analogues were investigated and compared with the same activities of a natural lipid A. These analogues are nonphosphorylated, C-1 or C-4' monophosphorylated and C-1,4' bisphosphorylated derivatives of beta-1,6-linked D-glucosamine disaccharide possessing both ester-bound and amide-bound fatty acid substituents. Fatty acid substituents of the analogues are tetradecanoyl (C14), (R)-3-hydroxytetradecanoyl (C14-OH) or (R)-3-tetradecanoyloxytetradecanoyl [C14-O-(C14)] groups. The biological activities of the samples were assayed after solubilization with triethylamine and complexing with bovine serum albumin. Interferon-inducing activity was exhibited by both the C-1 monophosphorylated compounds examined. Ester-bound and amide-bound fatty acid substituents of these compounds are both C14 or C14 and C14-OH, respectively. Nonphosphorylated, C-4' monophosphorylated and C-1,4' bisphosphorylated compounds possessing the same fatty acid substituents as those of the C-1 monophosphorylated compounds showed no detectable interferon-inducing activity. C-4' monophosphorylated compounds possessing C14-OH as ester-bound and C14-OH or C14-O-(C14) as amide-bound fatty acid substituents exhibited interferon-inducing activity, but nonphosphorylated compounds possessing the same fatty acid substituents did not. None of the analogues exhibited significant pyrogenicity nor proclotting enzyme of horseshoe crab activation activity under the conditions employed in this study.

Animals↗