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S Kitagawa

Publications and source records attributed to S Kitagawa.

At least 37 records · Page 2Linked to original sources
PubMed2001

New molecular assemblies of redox isomers, [CrIII(X4SQ)3-n(X4Cat)n]-n (X = Cl and Br; n = 0, 1, and 2), with metallocenium cations, [MIIICp2]+ (M = Co and Fe): X-ray crystal structures and physical properties.

A series of redox isomers of [CrIII(X4SQ)(X4Cat)2]2-, [CrIII(X4SQ)2(X4Cat)]-, and [CrIII(X4SQ)3]0 (X = Cl and Br, SQ = semiquinonate, and Cat = catecholate) have been synthesized and characterized as charge-transfer (CT) compounds with metallocenium cations: (CoIIICp2)2[CrIII(Cl4SQ)(Cl4Cat)2] (1), (CoIIICp2)2[CrIII(Br4SQ)(Br4Cat)2] (2), (FeIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)].C6H6 (4), (FeIIICp2)[CrIII(Br4SQ)2(Br4Cat)].CS2 (5), and (FeIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)][CrIII(Cl4SQ)3] (6). First, the oxidation states of the chromium complexes are strongly dependent on the redox potentials of the metallocenes used. The CoIICp2, exhibiting stronger reduction power than FeIICp2, is useful for two-electron reduction of the [CrIII(X4SQ)3]0, affording [CrIII(X4SQ)(X4Cat)2]2- (1 and 2), which are first isolated and crystallographically characterized in the solid state. In contrast the reaction with FeIICp2 affords only [CrIII(X4SQ)2(X4Cat)]- (4 and 5). Second, solvents influence crystal structures of these compounds. The solvent set of C6H6/CS2 gives 1:1:C6H6 compound 4 with unique charged anions, [CrIII(Cl4SQ)2(Cl4Cat)]-, while the other set, n-C6H12/CS2, affords 1:2 compound 6 including the two redox isomers, [CrIII(Cl4SQ)2(Cl4Cat)]- and [CrIII(Cl4SQ)3]0. The [CrIII(X4SQ)(X4Cat)2]2- anions in 1 and 2 show no significant interconnection between them (discrete type), while the [CrIII(X4SQ)2(X4Cat)]- anions in 4-6 show one-dimensional column-type structures with the aid of intermolecular stacking interactions of the ligand moieties. The anions in 4 show additional stacking interaction with the [FeIIICp2]+ to form one-dimensional ...[D][A][S][D][A]... (D = [FeIIICp2]+, A = [CrIII(Cl4SQ)2(Cl4Cat)]-, and S = C6H6) type mixed-stack arrangements similar to that of previously reported (CoIIICp2)[CrIII(Cl4SQ)2(Cl4Cat)].C6H6 (3). Compound 6 forms a two-dimensional sheet structure where the two redox isomers, [CrIII(Cl4SQ)2(Cl4Cat)]- and [CrIII(Cl4SQ)3]0, are included. The sheet is regarded as a mixed-valence molecular assembly. Two types of the anions, [CrIII(X4SQ)(X4Cat)2]2- (1 and 2) and [CrIII(X4SQ)2(X4Cat)]- (4-6), exhibiting an intramolecular mixed-valence state, show intramolecular intervalence CT transition (IVCT) from the Cat to the SQ at near 5800 and 4300 cm-1, respectively, both in the solution and in the solid states. The intermolecular mixed-valence state of 6 was characterized by absorption spectroscopy, electric conductivity, and SQUID magnetometry. Interestingly, this mixed-valence state of the chromium module is dependent on the redox active nature of the coordinated ligands.

Journal Article↗
PubMed2001

Estimation of the dissociation constants for functional groups on modified and unmodified silica gel supports from the relationship between electroosmotic flow velocity and pH.

Electroosmotic volume flow was directly observed in a simple instrument consisting of 1 cm long a home-made support, packed between two polyethylene frits in the polypropylene tube. Equations relating electroosmotic flow (EOF) velocity and pH for two functional groups on the surface of the solid materials were developed. With these equations, we can estimate the dissociation constants of two different kinds of functional groups on modified silica gel materials simultaneously. The dissociation constants of silanol groups, benzene sulfonic acid groups, and alkyl quaternary ammonium groups on the modified and unmodified silica gel supports were estimated. The estimated pK values of the silanol groups on the silica gel and modified silica gel surfaces are between 4.0 and 4.3. The estimated pK values of the benzene sulfonic acid groups and alkyl quaternary ammonium groups on the surface of the modified silica gel are 2.6 and 8.6, respectively.

Hydrogen-Ion Concentration↗
PubMed2001

Diverse effects of cytochalasin B on priming and triggering the respiratory burst activity in human neutrophils and monocytes.

Cytochalasin B, despite its potent enhancing effect on superoxide (O2-) release triggered by N-formyl-methionyl-leucyl-phenylalanine (FMLP) and many other agonists, significantly inhibited O2- release triggered by interleukin 8 (IL-8) and platelet-activating factor in human neutrophils. Cytochalasin B also enhanced changes in membrane potential stimulated by FMLP but inhibited those stimulated by IL-8. Using IL-8 as a triggering agonist, we found that the priming effect of tumor necrosis factor (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on O2- release was slightly but significantly potentiated by cytochalasin B. O2- release triggered by TNF and GM-CSF was completely abolished by cytochalasin B. In contrast to these diverse effects of cytochalasin B on O2- release, changes in cytoplasmic pH stimulated by FMLP, IL-8, TNF, and GM-CSF were not or were only minimally affected by cytochalasin B. Unlike human neutrophils, human monocytes stimulated by FMLP showed inhibition of O2- release and changes in membrane potential in response to cytochalasin B, and the priming effect of TNF and GM-CSF on O2- release in human monocytes was completely abolished by cytochalasin B. These findings indicate the diverse effects of cytochalasin B on phagocytes and suggest distinct regulatory mechanisms according to the functions, agonists, and cell types.

Adult↗
PubMed2001

Cytokine expression in rat molar gingival periodontal tissues after topical application of lipopolysaccharide.

It is well known that proinflammatory cytokines produced by host cells play an important role in periodontal tissue destruction. However, the localization of the cytokines in in vivo periodontal tissues during development of periodontal disease has not been determined. Immunohistochemical expression of proinflammatory cytokines including IL-1alpha, IL-1beta, and TNF-alpha was examined at 1 and 3 h, and 1, 2, 3, and 7 days after topical application of lipopolysaccharide (LPS; 5 mg/ml in physiological saline) from E. coli into the rat molar gingival sulcus. In the normal periodontal tissues, a small number of cytokine-positive epithelial cells were seen in the junctional epithelium (JE), oral sulcular and oral gingival epithelium, in addition to macrophages infiltrating in the subjunctional epithelial area and osteoblasts lining the alveolar bone surface. Epithelial remnants of Malassez existing throughout periodontal ligament were intensely positive for IL-1beta but negative for the other two cytokines. At 3 h after the LPS treatment, almost all cells in the JE were strongly positive for the cytokines examined. In addition, several cytokine-positive cells, including neutrophils, macrophages, and fibroblasts, were seen in the subjunctional epithelial connective tissue. At day 2, expression of the cytokines in the JE gradually decreased, while cytokine-positive cells in the connective tissue increased in number. Positive staining of the cytokines was seen in osteoclasts and preosteoclasts which appeared along the alveolar bone margin in this period. The number of cytokine-positive cells decreased by day 7. These findings indicate that, in addition to macrophages, neutrophils, and fibroblasts, the JE cells are a potent source of TNF-alpha, IL-1alpha, and IL-1beta reacting to LPS application, and suggest that JE cells may play an important role in the first line of defense against LPS challenge, and the proinflammatory cytokines transiently produced by various host cells may be involved in the initiation of inflammation and subsequent periodontal tissue destruction.

Animals↗
PubMed2001

Assessment of tear concentrations on therapeutic drug monitoring. II. Pharmacokinetic analysis of valproic acid in guinea pig serum, cerebrospinal fluid, and tears.

PURPOSE: To quantitatively describe the pharmacokinetics of valproic acid (VPA) in guinea pig serum (total [Cf+b] and free [Cf]), cerebrospinal fluid (CSF) [C]CSF and tears [C]T using a simple kinetic model, and to examine whether [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. METHODS: [Cf+b], [Cf], [C]CSF and [C]T were determined after bolus i.v. injection of 10 or 20 mg/kg VPA using GC/ECNCI/MS. RESULTS: [Cf+b] could be quantitatively described by a two compartment model with linear elimination kinetics. [Cf] was separately analyzed using multi-exponential equations. [C]CSF was analyzed using a simple kinetic model in which the CSF compartment is independently connected with the serum compartment by the apparent diffusion constants (KINCSF and KOUTCSF). [C]T was analyzed using the same simple kinetic model used for [C]CSF. The values of [C]CSF and [Cf] in the steady state can be represented by the following equations; [C]CSF = KINCSF/KOUTCSF x [Cf], [Cf] = KOUT/KINT x [C]T, and indicating that [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. CONCLUSIONS: The measurement of [C]T which can be collected non-invasively and estimated the pharmacokinetic parameters for [Cf], [C]CSF, and [C]T might be a very useful method for TDM of VPA.

Animals↗
PubMed2001

IgG subclasses of anti Saccharomyces cerevisiae antibody in inflammatory bowel disease.

Elevation of serum anti Saccharomyces cerevisiae antibody (ASCA) has been reported in patients with Crohn's disease. We analysed the subclasses of Immunoglobulin (Ig) G reaction in ASCA in sera from patients with inflammatory bowel disease, healthy controls, and patients with intestinal Behçet's disease. Serum samples were obtained from 29 patients with Crohn's disease, 30 patients with ulcerative colitis, 7 patients with intestinal Behçet's disease, and 12 healthy controls. Serum IgG subclasses IgG1, IgG2, IgG3, and IgG4 of ASCA were analysed using ELISA. IgG4 ASCA was significantly increased in patients with inflammatory bowel disease. In patients with intestinal Behçet's disease, IgG1, IgG3, and IgG4 ASCA were increased. Differential responses, in terms of subclasses in ASCA, were found in patients with inflammatory bowel disease and patients with intestinal Behçet's disease, which may represent different pathophysiologies of these intestinal inflammatory diseases.

Adult↗
PubMed2001

Usefulness of magnetic resonance imaging for surgical management of extravasation of an antitumor agent: a case report.

We report a case of extravasation of an antitumor agent by preoperative magnetic resonance (MR) imaging. MR studies demonstrated a decreased signal intensity on T1- and T2-weighted images and a strong enhancement of contrast media in injured tissue, including subcutaneous adipose tissue and deep fascia, which was cicatrical macroscopically. The MR findings were in good agreement with the macroscopic findings. We believe that MR imaging is useful for estimating deep tissue damage due to extravasation of an antitumor agent.

Adipose Tissue↗
PubMed2001

Effects of double-chained cationic surfactants n-dimethyldialkylammoniums on skin permeation of benzoic acid through excised guinea pig dorsal skin: comparison of their enhancement effects with hemolytic effects on erythrocytes.

We examined the effects of the double-chained cationic surfactants dimethyidialkylammoniums (CH3)2N+ (CnH(2n+1))2 on the permeation of benzoic acid through excised guinea pig dorsal skin. Among five dimethyldialkylammoniums tested (n=10-18), dimethyldidecylammonium (n=10) had dose-dependent enhancement effects at concentrations of more than 20 microM. Compared with the marked enhancement effects of dimethyldialkylammoniums with relatively shorter alkyl chains, those of long-chain dimethyldialkylammoniums (n=16, 18) were much less. We compared the enhancement effects of these cationic surfactants on skin permeation with their hemolytic effects on guinea pig erythrocytes. Their enhancement effects corresponded to their hemolytic activity. The findings suggest that dimethyldialkylammoniums with relatively shorter alkyl chains, which form either vesicles with looser molecular packing or micelles and appear to be present as surfactant monomers in higher ratios than those with longer alkyl chains, favor the interaction with skin. Their enhancement mechanism is possibly similar to that of single-chained cationic surfactants.

Algorithms↗
PubMed2001

Analysis of electron spin resonance spectra of alkyl spin labels in excised guinea pig dorsal skin, its stratum corneum, delipidized skin and stratum corneum model lipid liposomes.

The electron spin resonance (ESR) spectra of alkyl spin labels were observed in the excised guinea pig dorsal skin, its stratum corneum, delipidized skin and stratum corneum model lipid liposomes. The spectrum of 5-doxylstearic acid (5-NS) in the stratum corneum and order parameter obtained from the spectrum, indicated that the spin label was present in highly ordered lipid lamella. On the other hand, the spectrum of methyl ester of 5-NS (5-NMS) and its apparent rotational correlation time calculated from the spectrum, showed only a weakly immobilized component in the stratum corneum as well as in the whole excised skin. The ester spin label seemed to be scarcely present in the rigid lipid lamella, but mainly in the relatively fluid environment. On the other hand, cationic alkyl spin labels showed quite different spectra depending on their alkyl chain lengths. Long-chain 4-(N,N-dimethyl-N,-pentadecyl)ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl (CAT-15) seemed to be present in the protein region of the stratum corneum as we recently reported, whereas hydrophilic quaternary ammonium spin label 4-trimethylammonium-2,2,6,6-tetramethylpiperidine-1-oxyl (CAT-1) seemed to be present in the bulk water of the skin, even in delipidized skin. These findings indicated that the different interaction and different localization of the alkyl spin labels depended on their electronic charge as well as their alkyl chain lengths.

Animals↗
PubMed2001

CD71 antibody enhances iron uptake by mouse bone marrow cells and the survival potential of erythroid progenitor cells.

Transferrin has been shown to have cytoprotective functions. The aim of this study was to evaluate the effect of antibody against CD71 (transferrin receptor) on survival potential of erythroid progenitor cells. After anti-CD71 IgG or control IgG was reacted with cells for 20 min on ice, the uptake of transferrin-bound 59Fe by the MEL cells or the mouse bone marrow cells during 2-day incubation without erythropoietin was measured. Erythropoiesis was evaluated by addition of erythropoietin after 4-5 weeks' culture without erythropoietin or beta-mercaptoethanol, and production of cells containing hemoglobin was compared by immunocytological methods. MEL cells reacted with anti-CD71 IgG incorporated more transferrin-bound 59Fe than MEL cells reacted with control IgG. Uptake of transferrin-bound 59Fe by mouse bone marrow cells reacted with anti-CD71 IgG was also greater than by cells reacted with control IgG. Erythrocytes developed from cells reacted with anti-CD71 IgG and cultured for 4-5 weeks, but few erythrocytes developed from cells reacted with control IgG. Bone marrow cells depleted of TER119+ cells, CD34+ cells, or CD45+ cells and reacted with CD71 antibody did not differentiate into erythrocytes. Survival potential of erythroid progenitor cells were enhanced by reaction with anti-CD71 antibody.

Animals↗
PubMed2001

[Colonic varices; a case report].

Colonic varices is a rare entity that is caused by portal hypertension in most instances. In the case reported here, barium enema and colonoscopy showed multiple tortuous polypoid lesions with intact mucosal surface. Inferior mesenteric angiography showed arteriovenous malformation in the sigmoid colon, complete obstruction of the inferior mesenteric vein, and tortuous dilated marginal veins. We assume that the colonic varices of this case was secondary to complete obstruction of the inferior mesenteric vein following AVM of the sigmoid colon. Close follow-up should is warranted in cases of colonic varices because of the risk of bleeding.

Aged↗
PubMed2001

[Chronic myelogenous leukemia with marked thrombocytosis].

We report a case of chronic myelogenous leukemia (CML) with marked thrombocytosis. The patient was a 68-year-old woman who showed marked thrombocytosis (> 200 x 10(4)/microliter), a slightly increased leukocyte count without any immature myeloid cells in the peripheral blood, and no hepatosplenomegaly. Philadelphia chromosome (Ph) was detected by karyotype analysis and FISH. The bcr-abl transcript was detected by RT-PCR and the break point was located in the major bcr. Treatment with interferon-alpha was effective, reducing the proportion of Ph-positive cells from 56% to 7% within 21 months. Detailed study of atypical cases of CML such as the present one may provide additional information about the disease pathogenesis.

Aged↗
PubMed2001

[A case of postoperative gastric cancer responding to adjuvant chemotherapy with TS-1--a novel oral formation of 5-fluorouracil].

TS-1 is a novel oral formation of 5-fluorouracil, developed using tegafur and two biochemical modulations. We report the case of a patient with multiple lymph node metastases from gastric cancer that markedly responded to TS-1. A 70-year-old man suffering from hematemesis was admitted to our hospital. Computed tomography showed advanced gastric cancer with huge lymph node metastases. After non-curative operation, he received adjuvant chemotherapy with TS-1 for 12 weeks. CT revealed that almost complete reduction of the metastatic nodes was obtained. No serious adverse reactions were observed.

Aged↗
PubMed2001

[Phase I study with irinotecan hydrochloride (CPT-11) for advanced neuroblastoma].

A Phase I trial of irinotecan hydrochloride (CPT-11) was performed to determine the maximum tolerated dose (MTD), the dose-limiting toxicities, and the incidence and severity of other toxicities in children with advanced neuroblastoma. Three children received 11 courses of CPT-11 administered as a 90-min i.v. infusion, daily for 3 days every 21 days. Doses ranged from 100 mg/m2 to 220 mg/m2. Two peaks in the total number of instances of diarrhea was observed, 25 stools at 3 days and 32 stools at 10 days. Myelosuppression was well controlled and of brief duration. One child achieved a clinical complete response (CR) and 2 had a partial response (PR). The MTD of CPT-11 administration was 180 mg/m2 for 3 days. These results indicate the usefulness of CPT-11 for the treatment of advanced neuroblastoma. Further investigation is necessary to establish its role in combination chemotherapeutic regimens.

Adrenal Gland Neoplasms↗
PubMed2000

Molecular recognition of amines and amino esters by zinc porphyrin receptors: binding mechanisms and solvent effects.

Zinc porphyrin receptors bearing 12 ester groups in the meso phenyl groups (1-3) were prepared, and binding of amines and alpha-amino esters was studied with emphasis on the binding mechanisms. The X-ray crystallographic analysis of 5,10,15,20-tetrakis(2, 6-bis(carbomethoxymethoxy)-4-carbomethoxyphenyl)porphyrin (free base of 1) showed that the receptor has a binding pocket above the porphyrin plane. UV-visible titration experiments revealed that the zinc porphyrin receptors bound amines and alpha-amino esters with binding constants (K(a)) ranging from 0.5 to 52 700 M(-1) in CH(2)Cl(2) at 25 degrees C. The ester functional groups of 1 assisted the binding of aromatic alpha-amino esters (K(a) = 8 000-23 000 M(-1) in CH(2)Cl(2) at 25 degrees C) and inhibited the binding of bulky aliphatic alpha-amino esters (K(a) = 460 M(-1) for Leu-OMe in CH(2)Cl(2) at 25 degrees C), indicating that CH-pi type interactions and steric repulsions control the selectivity. The binding of amines and alpha-amino esters was tight both in a nonpolar solvent (CH(2)Cl(2)) and in a polar solvent (water) but loose in a solvent of intermediate polarity (H(2)O-MeOH (1:1)), demonstrating that two competitive driving forces are operating: (1) attractive electrostatic forces between host and guest such as coordination of the amino group to the zinc atom, and (2) entropic forces stemming from desolvation as well as enthalpic forces due to the host-guest dispersion forces. The former forces drive the binding in CH(2)Cl(2) while the latter forces drive the binding in water. The enthalpy changes in the binding in CH(2)Cl(2) and those in water range from -50 to -30 kJ mol(-1) and from -35 to 0 kJ mol(-1), respectively. The entropy changes in CH(2)Cl(2) and those in water range from -120 to -60 J K(-1) mol(-1) and from -50 to +60 J K(-1) mol(-1), respectively. Thus the binding in CH(2)Cl(2) is characterized by large negative enthalpy changes, while that in water by less negative entropy changes. These thermodynamic parameters also indicate that host-guest polar interactions (enthalpic forces) drive the binding in CH(2)Cl(2) while both host-guest dispersion interactions (an enthalpic force) and desolvation (an entropic force) drive the binding in water. Enthalpy-entropy compensation observed for the binding in water indicates that the binding of amines and amino esters in water by zinc porphyrins is associated with conformational changes as well as a high degree of dehydration. In CH(2)Cl(2), no clear compensation was observed, consistent with the mechanism that neither desolvation processes nor conformational changes contribute significantly to the binding energetics.

Binding Sites↗
PubMed2000

Configuration of the right portion of the caudate lobe with special reference to identification of its right margin.

The configuration of the right portion of the caudate lobe (CL), and especially the exact location of its right margin, remains obscure. This study aimed to identify this right margin according to reliable landmarks suitable for use during clinical examinations and surgery: (1) the bifurcation of the right portal vein, (2) the end of the right hepatic vein, and (3) the notch on the gallbladder fossa. The plane defined by these three landmarks is called the right paracaval plane. Dissection of 55 livers demonstrated that the entire CL was usually contained within the left half of the specimen after cutting along the right paracaval plane (Type A: 65.4%, 36/55). However, its right portion sometimes extended beyond this plane into the right half of the liver (34.6%, 19/55), forming one or two islands when viewed from the paracaval plane (Types B and C). We found two separate marginal configurations among the 19 rightward extensions of the paracaval portion: a tree-like, deep protrusion (11/19) and a relatively smooth border (8/19). The present results suggest the existence of reliable landmarks that will allow a right-side limit for surgical resection of the CL to be established: (1) the right paracaval plane (60% reliability), (2) 10 mm to the right of the plane, including the terminal of the right hepatic vein (80% reliability), and (3) the widest margin, including the 30 mm to the right of the right paracaval plane, the right side running along the inferior vena cava, and the diaphragmatic surface around the end portions of the three main hepatic veins (100% reliability).

Aged↗
PubMed2000

Proposal of sampling process for collecting human sweat and determination of caffeine concentration in it by using GC/MS.

Caffeine concentration in human sweat was estimated by measuring separately the amounts of water and caffeine. After washing a finger with tap water for 15 s and waiting 2 min for drying, 70 microL aqueous ethanol solution in a small vial (0.6 mL) was used to sample for several minutes. Then 3 microL of the aliquot was used for GC/MS analysis of caffeine. As a first-order relationship between the sweat amount secreted on the left and right hands was obtained (correlation factor 0.848), the amount of sweat secretion during sampling on one hand was estimated by the value obtained on the other hand. This new indirect evaluation was used for the estimation of the amount of sweat secreted during sampling. Typical variations of caffeine concentration in sweat were demonstrated. Thirty minutes after the intake of caffeine, it was secreted in sweat, and the secretion had continued for more than 4 h.

Caffeine↗