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Biomedical subjects

S Kusumoto

Publications and source records attributed to S Kusumoto.

At least 91 records · Page 5Linked to original sources
PubMed1994

Identification of trisaccharide Xyl alpha 1-->3Xyl alpha 1-->3Glc in human urine.

Oligosaccharides in human urine were converted to pyridylamino (PA)-derivatives. From the PA-oligosaccharides, a saccharide that was chromatographically identical with a synthetic standard, Xyl-alpha 1-->3Xyl alpha 1-->3Glc-PA, was isolated by gel filtration and HPLC. Structure analysis showed that the saccharide was Xyl alpha 1-->3Xyl-alpha 1-->3Glc-PA. It is likely that Xyl alpha 1-->3Xyl alpha 1-->3Glc originated from such glycoconjugates as blood coagulation factors VII and IX, and protein Z.

Carbohydrate Sequence↗
PubMed1993

Structural characterization of heparin's binding domain for human platelets.

The structural features of heparin that are involved in binding to human platelets were investigated by a competitive binding approach. A range of heparin-derived glycosaminoglycans (GAGs) with relatively defined structure were prepared by different methods of depolymerization of pharmaceutical heparin, followed by fractionation according to molecular weight and net charge. Competitive binding to platelets was dependent on molecular weight but not on the net charge of the GAGs. The method for depolymerization significantly affected the binding activity of the resulting GAG. Heparinase I and nitrous acid depolymerization produced GAGs with lower binding affinity for platelets than those GAGs derived from the treatment with periodate followed by alkali. The IC20 (concentration producing 20% inhibition of binding) was 0.05 microM for unfractionated heparin, 0.11 microM for a periodate treated GAG, and 2 microM for comparably sized GAGs (M(r) approximately 6,000-8,000) derived by heparinase I or nitrous acid treatment. Thus, the disaccharide units GlcNSO3-6S--IdoA-2S or GlcNSO3--IdoA-2S [(2-deoxy-2-sulfoamido-6-O-sulfo-alpha-D-glycopyranosyl)-(1- 4)-O-(2-O-sulfo-alpha-L-idopyranosyluronic acid) or (2-deoxy-2-sulfoamido-alpha-D-glycopyranosyl)-(1-4)-O-(2-O-s ulfo-alpha-L-idopyranosyluronic acid)] may be crucial elements for binding to the platelet, because these are known to be preserved during periodate/alkali treatment, but readily decomposed by heparinase I and nitrous acid. Understanding this structural specificity for platelet binding may be useful for the development of heparins with high or low platelet reactivity.

Binding Sites↗
PubMed1993

The chemical structure of bacterial endotoxin in relation to bioactivity.

Lipopolysaccharides (LPS) constitute the O-antigens and endotoxins of Gram-negative bacteria. Whereas both the polysaccharide and lipid portion of LPS contribute to the pathogenic potential of this class of bacteria, it is the lipid component (lipid A) which determines the endotoxic properties of LPS. The primary structure of lipid A of various bacterial origin has been elucidated and Escherichia coli lipid A has been chemically synthesized. The biological analysis of synthetic lipid A partial structures proved that the expression of endotoxic activity depends on a unique structural arrangement and conformation. Such analyses have furthermore provided insight into the determinants required for lipid A binding to and activation of human target cells. Present research efforts aim at the molecular characterization of the specificity, modulation and biomedical consequences of the interaction of lipid A with host cells.

Animals↗
PubMed1993

The antibody reactivity of monoclonal lipid A antibodies is influenced by the acylation pattern of lipid A and the assay system employed.

The influence of the acylation pattern of lipid A on the reactivity of murine monoclonal antibodies (mAb) was tested in different assay systems with synthetic lipid A antigens. Both the number and type of fatty acids had an impact on the antigen amounts needed for optimal sensitization of sheep red blood cells, on the inhibition capacity of compounds and on the reactive antigen amounts in enzyme immunoassay and dot blot assay. Results obtained with two pentaacyl isomers indicated that the location of fatty acids is of no importance. Although all mAbs used recognized epitopes residing in the hydrophilic backbone of lipid A, their reactivities were greatly influenced by the number as well as the type of acyl chains present. In the various assays, the mAbs reacted either similarly or discrepantly suggesting that epitopes are exposed differently in the test systems. We conclude that for the determination of the reactivity of lipid A mAbs it is useful and sometimes necessary to run various assays in parallel and to compare mAbs on the basis of reaction patterns.

Acylation↗
PubMed1993

Increased level/dose ratio of amphotericin-B in premature infants with renal failure.

We introduced continuous intravenous infusion of amphotericin-B (AMPH-B) to extremely low birthweight (ELBW) infants (< 1000 g) with or without renal failure as a single agent for treating definite or probable systemic candidiasis. The species of Candida isolated from blood or tracheal aspirate or urine were C. albicans in seven infants, C glabrata in two, C. tropicalis in one and C. parapsilosis in one. The minimal inhibitory concentrations (MIC) of AMPH-B required against these isolates were less than 0.2 micrograms/mL except for that against one strain of C. albicans (0.78 microgram/mL). Serum AMPH-B levels were 0.31-0.78 (0.51 +/- 0.14) micrograms/mL when doses of 0.2-0.55 (0.32 +/- 0.11) mg/kg per day were being administered. The serum level was higher than the MIC of each isolate in all but one infant who died of disseminated intravascular coagulation and Candida pneumonia. Another infant died of congenital heart disease. The other nine infants survived. The serum level showed no correlation with the daily dose. The ratio of the serum level to the daily dose (L/D ratio) showed a significant correlation to serum creatinine (r = 0.787) and the linear regression curve followed the equation: L/D ratio = 0.223 x serum creatinine + 1.11 (P < 0.01). Few adverse effects due to AMPH-B were noted. Our data may give a simple reference to serum AMPH-B levels during continuous intravenous infusion from the dose and the serum creatinine level.

Acute Kidney Injury↗
PubMed1993

Chemical and biological degradation of 5-fluorouracil prodrugs having high serum albumin binding potencies.

In order to understand the fundamental structural features which yield both high serum albumin binding potency and desired property as a prodrug, the derivatization was performed at N-1 or N-3 position in 5-fluorouracil. The N-3 derivatives were more stable than N-1 derivatives in vitro, whereas they were metabolized quickly in vivo. It is suggested that N-1 position should be blocked to avoid fast metabolism in vivo.

Animals↗
PubMed1993

The synthesis and in vitro and in vivo stability of 5-fluorouracil prodrugs which possess serum albumin binding potency.

For a new drug delivery system of 5-fluorouracil, we prepared prodrugs possessing certain desired properties. The prodrugs, 1-(N-4-chlorophenyl-N-methylcarbamoyl)-5-fluorouracil and 1-(N-2,4-dichlorophenyl-N-methylcarbamoyl)-5-fluorouracil, contain high serum albumin binding potency and a comparably long half life in the bloodstream in vivo to Tegafur. These two prodrugs are expected to be retained in the bloodstream as a polymeric complex with albumin and to circulate in the body for a long time, like a polymeric prodrug.

Animals↗
PubMed1992

The oligosaccharides in a recombinant hepatitis B virus surface antigen (HBsAg) carrying the pre-S2 region derived from yeast.

The N- and O-linked oligosaccharides in a yeast-derived HBsAg M protein (pre-S2 + S) were analyzed. Two major structures of the N-linked oligosaccharides bound to residue Asn4 were determined to be high-mannose type oligosaccharides, Man7GlcNAc2 and Man8GlcNAc2, by two-dimensional sugar mapping of the corresponding pyridylamino oligosaccharides. Peptide mapping of the M protein, sequence analysis of the glycopeptides after beta-elimination under reducing conditions and sugar-composition analysis revealed that the O-linked oligosaccharides were composed solely of mannose and bound to residue Ser5, Thr6, Thr7, Ser27, Ser28, Ser29 and Thr31 in the pre-S2 region.

Amino Acid Sequence↗
PubMed1992

Modulation of lipopolysaccharide-induced production of tumor necrosis factor, interleukin 1, and interleukin 6 by synthetic precursor Ia of lipid A.

Endotoxin (lipopolysaccharide, LPS) induces the production of mediators of inflammation, which exerts pathophysiological effects such as fever or shock in mammals. In the present study we have investigated the modulation of LPS by the synthetic non-active tetraacylated precursor Ia of lipid A (compound 406) in the induction of tumor necrosis factor (TNF), interleukin 1 (IL-1) and interleukin 6 (IL-6) in human peripheral blood mononuclear cells (PBMC) and in human peripheral blood monocytes (PBMo). PBMC stimulated with LPS released TNF in a concentration dependent manner. Release of biologically active TNF, IL-1 and IL-6 was first detectable 4 h after LPS stimulation. Compound 406 alone in all concentrations tested did not induce TNF, IL-1 or IL-6 release, intracellular TNF or IL-1 beta, or mRNA for TNF or IL-1. Added to PBMC 1 h before LPS compound 406 enhanced or suppressed TNF release and suppressed IL-1 and IL-6 release depending on the ratio of concentrations between stimulator (LPS) and modulator (compound 406). In contrast to LPS stimulation alone TNF, IL-1 and IL-6 release in presence of compound 406 was delayed and first detectable after 6 to 8 h. Compound 406 was able to suppress LPS-induced intracellular TNF and IL-1 beta in PBMC. Added to PBMo 1 h before LPS it totally inhibited the production of mRNA for TNF and IL-1. When added to PBMC 1 h after LPS, TNF release was suppressed in a concentration-dependent way and release of biologically active TNF, IL-1 and IL-6 could again be detected for the first time after 4 h. Compound 406 was not able to inhibit phorbol 12-myristate 13-acetate (PMA)-induced TNF and IL-1 release in PBMo which suggests that its modulating effect is LPS-specific. This study provides evidence that the modulating effect of compound 406 on the LPS induction of TNF, IL-, 1 and IL-6 could be due to competitive binding.

Animals↗
PubMed1992

Modulation of endotoxin-induced monokine release in human monocytes by lipid A partial structures that inhibit binding of 125I-lipopolysaccharide.

We have previously shown that the synthetic tetraacyl precursor Ia (compound 406, LA-14-PP, or lipid IVa) was not able to induce the production of tumor necrosis factor, interleukin-1, and interleukin-6 in human monocytes but strongly antagonized lipopolysaccharide (LPS)-induced formation of these monokines. This inhibition was detectable at the level of mRNA production. To achieve a better understanding of molecular basis of this inhibition, we investigated whether lipid A precursor Ia (LA-14-PP), Escherichia coli-type lipid A (LA-15-PP), Chromobacterium violaceum-type lipid A (LA-22-PP), and synthetic lipid A partial structures and analogs (LA-23-PP, LA-24-PP, and PE-4) were able to influence the binding of 125I-LPS to human monocytes and compared this inhibitory activity with the agonistic and antagonistic action in the induction of monokines in human monocytes. 125I-LPS (20 ng per well) was added to human monocytes in the presence or absence of unlabeled rough Re mutant-derived LPS (Re-LPS) or lipid A compounds, and specific LPS binding was determined after 7 h. This binding was found to be dependent on CD14 as shown by the use of an anti-CD14 monoclonal antibody. Compound LA-14-PP was found to inhibit the binding of 125I-LPS to the cells in a similar dose-response to that of unlabeled LPS. This shows that the inhibitory capacity on LPS binding does not correlate with the monokine-inducing capacity because Re-LPS is active in inducing tumor necrosis factor, interleukin-1, and interleukin-6, while LA-14-PP is not. The strong capacity of LA-14-PP to inhibit 125I-LPS binding, however, correlates with the strong inhibitory capacity of this compound on LPS-induced monokine production. Compounds LA-15-PP, LA-23-PP, and LA-24-PP were active in the inhibition of 125I-LPS binding but were 5- to 10-fold weaker than Re-LPS and LA-14-PP. Of all lipid A structures tested, compound LA-22-PP expressed the weakest inhibitory capacity on LPS binding. These compounds showed again that the activity of binding inhibition does not correlate with the monokine-inducing capacity. We assume that the inhibitory effects of lipid A partial structures on LPS-induced monokine production have their origin in a competitive inhibition between LPS and the lipid A partial structures for the same binding site on the cell membrane.

Antigens, CD↗
PubMed1992

Characterization of the epitope specificity of murine monoclonal antibodies directed against lipid A.

A series of monoclonal antibodies directed against lipid A was characterized by using synthetic lipid A analogs and partial structures. These compounds vary in phosphate substitution, acylation pattern (type, number, and distribution of fatty acids), and, in the case of monosaccharides, in their backbone glycosyl residue. The monoclonal antibodies tested could be subdivided into five groups according to their reactivity patterns. One group reacted exclusively with 1,4'-bisphosphoryl lipid A, and a second also reacted with 4'-monophosphoryl lipid A. Two further groups recognized either 4-phosphoryl or 1-phosphoryl monosaccharide partial structures of lipid A. The fifth group reacted with 4-phosphoryl monosaccharide structures and with phosphate-free compounds. Antibodies reactive with monosaccharide structures also recognized their epitopes in corresponding phosphorylated disaccharide compounds. Both groups of monosaccharide and monophosphoryl lipid A-recognizing antibodies have access to their epitopes in bisphosphoryl compounds as well. Because of this unidirectional reactivity with more complex structures, the various specificities cannot be distinguished by using bisphosphoryl lipid A (e.g., Escherichia coli lipid A) as a test antigen. The epitopes recognized by the various monoclonal antibodies all reside in the hydrophilic backbone of lipid A, and there was no indication that fatty acids were part of the epitopes recognized. Nevertheless, the reactivities of compounds in the different test systems are strongly influenced by their acylation patterns; i.e., acyl groups may modulate the exposure of lipid A epitopes.

Acylation↗
PubMed1992

Structural features that influence the ability of lipid A and its analogs to abolish expression of suppressor T cell activity.

Lipid A preparations derived from the lipopolysaccharides of several gram-negative bacteria, as well as chemically defined synthetic lipid A's and their analogs (both glucosamine mono- and disaccharides), were used to establish the chemical structures required for (i) abolishing the expression of suppressor T cell (Ts) function and (ii) inducing polyclonal activation of B cells. Salmonella minnesota R595 lipid A (diphosphoryl lipid A) possesses both of these activities. Decreasing the number of phosphate groups in lipid A from two to one (monophosphoryl lipid A) as well as decreasing the fatty acyl content, primarily by removing the residue at the 3 position, resulted in a progressive reduction in toxicity; however, these structural modifications did not influence its ability to abolish the expression of Ts function. Reducing the fatty acyl content from five to four (lipid A precursor IVA or Ia) eliminated the capacity to influence Ts function but not to induce polyclonal activation of B cells. None of the monosaccharide analogs of lipid A examined influenced the expression of Ts activity, although some were able to activate B cells polyclonally. Thus, in order to be able to abolish the expression of Ts function, lipid A (i) must be a glucosamine disaccharide, (ii) may have either one or two phosphate groups, and (iii) must have at least five fatty acyl groups. Also, the chain length of the nonhydroxylated fatty acid, as well as the location of acyloxyacyl groups (2' versus 3' position), may play an important role. These findings indicate that the chemical structures responsible for the toxicity of lipid A differ from those that influence its capacity to abolish the expression of Ts function and to induce polyclonal activation of B cells.

Animals↗
PubMed1992

Biological activity of synthetic phosphonooxyethyl analogs of lipid A and lipid A partial structures.

We investigated the biological activity of four new synthetic analogs of lipid A, termed PE-1, PE-2, PE-3, and PE-4. All compounds contain an alpha-oxyethyl-linked (-O-CH2-CH2-) phosphoryl group in position 1 of the reducing glucosaminyl residue (GlcN I) of lipid A. PE-1 is a hexaacylated analog of Escherichia coli lipid A (compound 506). PE-2 differs from PE-1 in carrying two myristic acid residues at GlcN I. PE-3 has the same acylation pattern as PE-2, but GlcN I is present in the beta anomeric form. Finally, PE-4 represents an analog of tetraacyl precursor Ia (compound 406). Structure-activity relationships of these compounds were determined by measuring their capacity to induce tumor necrosis factor alpha, interleukin 1, and interleukin 6 release by human mononuclear cells and to cause mitogenicity of murine spleen cells. The results show that replacement of the glycosidic phosphoryl residue by a phosphonooxyethyl group had no substantial effect on the biological activity of compounds. However, the anomeric configuration of GlcN I was found to be of great biological relevance, as, in general, the alpha anomer (PE-2) expressed high activity, and the beta anomer (PE-3) expressed low mediator-inducing and mitogenic activity. The absence of the 3-hydroxyl groups within the acyl residues at GlcN I in PE-2 was found to only slightly affect the induction of monokines in human mononuclear cells compared with that of PE-1 or lipid A (506). These stable 1-phosphonooxyethyl analogs of lipid A may be candidates in the development of immunomodulators for the treatment of systemic endotoxicosis.

Animals↗
PubMed1992

Deamidation at asparagine-88 in recombinant human interleukin 2.

Reversed-phase high-performance liquid chromatography (RP-HPLC) and protein-chemical analysis revealed that only Asn88 in recombinant human interleukin 2 (rIL-2) is liable to be deamidated during a long period of storage in aqueous solutions (pH 5.0) at 25 degrees C, even though there are eight asparagine and six glutamine residues. The deamidation occurred more easily at 40 degrees C than at 25 degrees C but did not occur at all at temperatures below 5 degrees C. The biological activity of Asn88-deamidated rIL-2 was found to be almost the same as that of intact rIL-2, whereas its isoelectric point (pI 7.6) is different from that of intact rIL-2 (pI 7.9).

Amides↗
PubMed1992

[Hairy cell leukemia successfully treated with deoxycoformycin].

A 45-year-old male was hospitalized on September 2, 1989 with chief complaints of general fatigue and fever. Physical examination revealed hepatomegaly and massive splenomegaly. Laboratory tests on admission showed Hb of 7.5g/dl, PLT 4.8 x 10(4)/microliters and WBC 9,610/microliters with 81% hairy cells. Bone marrow aspirate demonstrated 55.1% hairy cells and moderate myelofibrosis. Cytochemically, hairy cells were positive for tartrate-resistant acid phosphatase (TRAP). Surface markers were SmIg G+ A+ kappa +, CD11b+, CD11c+, CD19+, CD20+, CD21-, CD25+, HC2+, HLA-DR+. From these findings, a diagnosis of hairy cell leukemia (HCL) was made. After administration of deoxycoformycin (DCF) at a dose of 5.0mg/m2 1-2 times monthly, splenomegaly disappeared, as did hairy cells from the peripheral blood. Hematological level returned to within normal range except for the presence of 1.2% hairy cells and mild myelofibrosis in bone marrow aspirates. DCF has so far been effective for this patient. While DCF has been reported to be effective in the treatment of HCL in the West, it has not been determined in Japanese patients with HCL, who have different hematologic features from those of HCL patients in the West.

Humans↗
PubMed1992

Inhibition of endotoxin or lipid A-induced tumor necrosis factor production by synthetic lipid A partial structures in human peripheral blood mononuclear cells.

Most of the toxic reactions during Gram-negative infections are mediated by inflammatory cytokines induced by endotoxin, also termed lipopolysaccharide (LPS). To evaluate the possibility of synthetic derivatives of LPS to antagonize endotoxin-mediated activities, we have examined the effect of synthetic lipid A partial structures, precursor Ia (compound 406 or LA-14-PP) and lipid X (compound 401) on in vitro LPS or lipid A-induced release of tumor necrosis factor (TNF) by human peripheral blood mononuclear cells. In agreement with previous reports it was shown that LPS of Salmonella abortus equi and synthetic Escherichia coli-type lipid A (compound 506 or LA-15-PP) have potent TNF-inducing capacity. The maximum release of TNF was found after stimulation with 1 to 10 ng/ml of LPS or 10 to 1000 ng/ml of lipid A. Synthetic precursor Ia and lipid X failed to induce TNF release, but could inhibit LPS or lipid A-induced TNF release in a dose-dependent manner. Inhibition was not due to a shift of the kinetic of cytokine release, and was observed in the early stage of TNF production. Moreover, we found that the synergistic effect of interferon-gamma with LPS in induction of TNF release could also be counteracted by the addition of synthetic precursor Ia. The observation that precursor Ia failed to inhibit the induction of TNF by Bacillus Calmette-Guérin, Staphylococcus aureus cowan I or lipopeptide indicated that specific mechanisms are involved in suppression by lipid A partial structures on LPS-induced cytokine production.(ABSTRACT TRUNCATED AT 250 WORDS)

Endotoxins↗
PubMed1992

[Magnetic resonance imaging of the bone marrow in patients with aplastic anemia and myelodysplastic syndrome].

Magnetic resonance imaging (MRI) of bone marrow was performed in 16 patients with aplastic anemia (AA) and myelodysplastic syndrome (MDS). Sagittal images from the lower thoracic and lumbar vertebral marrow were evaluated on short TI IR sequences (STIR, IR 2000/160/20). Four distinct patterns of signal intensity (SI) of the STIR images corresponding with active red marrow were classified as follows: pattern I, homogeneously low SI (4 cases); II, marginally high SI (2 cases); III, heterogeneously high SI (8 cases); IV, homogeneously high SI (2 cases). The SI distribution of STIR images strongly correlated with the cellularity of clot specimens of aspirates from sternum using the Wiebel test plate. In all three patients with AA, the STIR images revealed pattern I. In 8 of 13 cases of MDS patients, the STIR images were classified into pattern III. In one patient with hypoplastic MDS, the STIR image showed low SI. The STIR images of two AA patients at clinical remission after treatment showed marginally high SI similar to those of normal marrow. MRI of bone marrow can be a useful technique for the diagnosis of AA and MDS and for monitoring therapeutic effects.

Adult↗