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Biomedical subjects

K Takano

Publications and source records attributed to K Takano.

At least 181 records · Page 10Linked to original sources

Differences in clinical features and computed tomographic findings between embolic and non-embolic acute ischemic stroke: a quantitative differential diagnosis.

A diagnosis based on the presumed mechanism of stroke onset is useful for management strategies in acute ischemic stroke. Ninety-two patients with embolic (cardiac or artery-to-artery) and 107 with non-embolic (thrombotic or hemodynamic) stroke were diagnosed on strict cerebral angiographic criteria alone. To clearly discriminate between these two groups, the neurological and computed tomographic (CT) findings were then compared. Rapidity of onset, vomiting, urinary incontinence, level of consciousness, cervical bruit, anisocoria, tongue deviation, sensory disturbance, and CT findings (location of hypodense area, findings of brain edema and hemorrhagic transformation) were discriminatory factors between the two groups (p<0.01). According to these 11 items, we prepared a numerical table for quantitative differential diagnosis. A diagnostic accuracy of 98.9% for embolic and 87.9% for non-embolic stroke in internal verification, and 90.0% and 82.9%, respectively, in external verification was observed. The differences in clinical features and CT findings between embolic and non-embolic stroke may reflect the pathophysiological mechanisms of the occlusive process of cerebral artery as well as the extent and severity of ischemia.

Acute Disease↗

O/W lipid emulsions for parenteral drug delivery. IV. Changes in the pharmacokinetics and pharmacodynamics of a highly lipophilic drug, menatetrenone.

The pharmacokinetics and pharmacodynamics of antihemorrhagic vitamin, menatetrenone after intravenous injection as the lipid emulsion, were compared to those as the micellar solutions. Menatetrenone was selectively delivered to the liver, lungs and spleen and retained in them. Hepatic and splenetic concentration at 6 h (C6h) increased 21.6- and 27.1-fold, respectively, and the area under the tissue concentration-time curve up to 6 h (AUC(0-6h)) were 2.3- and 11.4-fold, respectively, when compared with its micellar solution. Antihemorrhagic effect of menatetrenone was assessed using warfarin-induced hypoprothrombinemic rats. The lipid emulsion of menatetrenone decreased the prothrombin time at 6h after intravenous injection more effectively than micellar solution. The dose response curves indicated that the efficacy of the lipid emulsion was 2.4-2.9 times that of a micellar solution, and this was correlated with AUC(0-6h) rather than C6h. The plasma level of clotting factor VII and the hepatic level of descarboxyprothrombin were also recovered more effectively, while no significant differences were noted between the two formulations for the plasma level of factor II or descarboxyprothrombin at the dose levels examined. Although selective delivery of menatetrenone in the liver by the lipid emulsion was due to phagocytosis by non-parenchymal cells, menatetrenone in the whole liver appeared to contribute to recovery from hypoprothrombinemia.

Analysis of Variance↗

Rhombencephalosynapsis: cerebellar embryogenesis.

We describe two infants in whom rhombencephalosynapsis was diagnosed with MR imaging in vivo. In contrast to Dandy-Walker malformation, the vermian maldevelopment in this anomaly is characterized by an absence of the anterior vermis and a deficiency of the posterior vermis. The cerebellar hemispheres are fused. In an attempt to identify the pathogenesis of these anatomic manifestations, we question the traditional concept of the embryologic development of the cerebellar primordium.

Brain↗

[Toremifene sensitized the effect of adriamycin on human breast cancer cell lines].

A experimental study was reported here to clarify the chemosensitizing effect of Toremifene (Tor) on human breast cancer cell lines. MCF7, estrogen dependent adriamycin (ADM) resistant cell, and MDA-MB231, estrogen independent cell, were preincubated for 8 hours with Tor 0, 4 or 10 microM, then with ADM 0-10 micrograms/ml for one hour. After that, cells were cultured for 24 hours, and their cell cycle and growth were analyzed with flow-cytometry and MTT assay, respectively. Furthermore, the ADM concentrations of these cells were measured by high-performance liquid chromatographic assay (HPLC). Although flowcytometric analysis showed the enhancement of Gz block only in MCF7 at the ADM concentration with 5 micrograms/ml, the sensitizing effect was revealed by MTT assay, and the elevation of ADM concentration was found in HPLC assay in both cells. The chemosensitizing effect of Toremifene was observed in estrogen dependent and independent cell lines.

Antibiotics, Antineoplastic↗

[Analysis for predicting the prognostic factors of gastrointestinal tract leiomyosarcoma using MIB-1 and DNA flow cytometry].

PURPOSE: The present study was undertaken to investigate the possibility of determining a prognosis for gastrointestinal tract leiomyosarcoma with the use of DNA analysis and MIB-1 staining. SUBJECTS AND METHODS: Malignant tumors originating in smooth muscle of the gastrointestinal tract, surgically excised from 23 lesions in 17 patients (stomach; 8 cases, 12 lesions; small intestine: 6 cases, 8 lesions; colon: 3 cases, 3 lesions) and embedded in paraffin, were examined. DNA was analyzed using flow cytometry to produce a DNA histogram, and aneuploidy and diploidy were found. MIB-1 staining was done in conformity with the ABC method. RESULTS: 1. An investigation of prognoses using the Kaplan-Meier method revealed a tendency for more favorable prognoses in patients determined to be aneuploid through DNA analysis. However, this was not significantly better than those exhibiting diploidy. 2. All patients who died had a MIB-1 staining positivity rate of over 10%, while all patients who had no recurrence within one year or survived had a MIB-1 staining positivity of less than 10%. 3. No consistent trends were observed between MIB-1 positivity rate and DNA analysis, MIB-1 positivity rate and size of tumor, or DNA analysis and size of tumor. 4. The MIB-1 positivity rate of patients with remote metastases was significantly greater than that of patients with no remote metastases. CONCLUSION: From the fact that patients with MIB-1 positivity rates of greater than 10% had a poor prognosis, while those with rates of less than 10% had a favorable prognosis, we conclude that a MIB-1 positivity rate of 10% is an important value in determining the prognosis of patients with gastrointestinal tract leiomyosarcomas.

Adult↗

Pharmacokinetic characteristics of cisapride in elderly patients.

We demonstrated pharmacokinetic characteristics of cisapride in elderly patients (85+/-6 years) who had suffered from constipation based on intestinal motility dysfunction. After a single p.o. dose of 2.5 mg cisapride tablet on the first day, plasma unchanged cisapride concentrations were detected at 9 points within 24 hours, using high-performance liquid chromatography method. Subsequently, the patients were treated with cisapride 3 times daily during next 26 days (from the day 2 to the day 27). On the 28th day, a cisapride tablet was given once in the morning and blood samples were obtained with the same procedure as that on day 1. The obtained elimination half-life averaged 21.8+/-10.6 hours, which seems to be considerably longer than those previously reported. The area under the time-concentration curve (AUC) on the day 28 was 2.7 times larger than AUC on the day 1, suggesting that plasma cisapride concentrations can become higher than expected by physicians when given 3 times daily to extremely elderly patients. Because cisapride sometimes induces fatal ventricular arrhythmias and sudden death in a concentration-dependent manner, this medicine should be administered once or twice per day to such patients.

Administration, Oral↗

Immunogold labeling of peroxidase in salivary gland acinar cells using an improved tissue preparation procedure: rapid freezing and Lowicryl embedding.

The immunocytochemical localization of peroxidase in the acinar cells of the Mongolian gerbil parotid gland was studied using aldehyde-fixed tissue prepared by rapid freezing and low-temperature embedding in Lowicryl K4M resin. This freeze-embedding method was developed to provide improved preservation of cell ultrastructure and optimum accessibility of antigens, combined with relative technical ease. Immunogold labeling with antibody to peroxidase was found mainly in the dense cores of mature and immature secretory granules. In the trans Golgi area, the rough endoplasmic reticulum (rER), many clusters of smooth vesicles, and short tubular structures showed a variable labeling intensity. The results demonstrate the utility of this newly-developed preparative method and confirm the presence of peroxidase in elements of the Golgi apparatus.

Acrylic Resins↗

Reproducibility and reliability of middle cerebral artery occlusion using a silicone-coated suture (Koizumi) in rats.

The best technical approach to rat middle cerebral artery occlusion (MCAO) using a nylon-monofilament suture remains unsettled, regarding the usefulness of coated or uncoated sutures. Three investigators with different degrees of experience: A, well skilled; B, 2 years of experience; C, a novice with 6 months of experience, each subjected 10 Sprague-Dawley rats to permanent MCAO using low-viscosity silicone-coated sutures with a mean diameter 0.468+/-0.013 mm (mean+/-S.D.) at the tip and 0.361+/-0.013 mm in the body. Post-mortem corrected infarct size 24 h after MCAO was similar among the three investigators: A, 204.7+/-33.2 mm3; B, 212.6+/-42.8, and C, 195.9+/-44.4. The coefficient of variation was 16.2% to 22.7%, and 19.4% for the three investigators. This study suggests that experimental stroke with silicone-coated sutures (Koizumi's method) provides good reproducibility and reliability, among investigators of varying experience.

Animals↗

Contribution of water molecules in the interior of a protein to the conformational stability.

Water molecules frequently occur in the interior of globular proteins. To elucidate the contribution of buried water molecules to the conformational stability of a protein, we examined the crystal structures and the thermodynamic parameters of denaturation of six Ile to Ala/Gly mutant human lysozymes, in which a cavity is created at each mutation site by the substitution of a smaller side-chain for a larger one. One or two ordered water molecules were found in the cavities created in some mutants (I106A, I59A and I59G). The cavity volumes for these three mutants were bigger than those that remained empty in the other mutants. The stability of the mutant proteins with the newly introduced water molecules was about 8 kJ/mol higher than that expected from the change in hydrophobic surface area (DeltaDeltaASAHP) exposed upon denaturation. It was concluded that a water molecule in a cavity created in the interior of a protein contributes favorably to the stability.

Amino Acid Substitution↗

Different G proteins mediate somatostatin-induced inward rectifier K+ currents in murine brain and endocrine cells.

1. Types of G proteins (G protein alpha-subunit subtypes) which mediate the activation of inward rectifier K+ currents by somatostatin (somatotrophin release-inhibiting factor, SRIF) were determined in cultured locus coeruleus neurones from newborn rats and in AtT-20 cells (a mouse pituitary cell line). 2. The whole-cell patch clamp technique was used together with injection of antibodies against pertussis toxin (PTX)-sensitive G protein alpha-subunits or with injection of antisense (or sense) oligonucleotides against these G proteins. 3. In locus coeruleus neurones, the SRIF-induced activation of inward rectifier K+ currents was inhibited by anti-G alpha i1/G alpha i2 antibody injection, but not by anti-G alpha i3 or by anti-G alpha o/G alpha i3 antibody injection, suggesting that the SRIF response is mediated through G alpha i1 and/or G alpha i2. 4. The SRIF-induced activation of the inward rectifier was suppressed in locus coeruleus neurones after injection of antisense oligonucleotides against G alpha i2, but not by injection of sense oligonucleotides against G alpha i2. Injection of antisense (or sense) oligonucleotides against G alpha i1, G alpha i3 and G alpha O (common) had no effect. These results suggest that G alpha i2 is involved in this SRIF response. 5. In AtT-20 cells, the SRIF-induced activation of inward rectifier K+ currents was suppressed by injection of anti-G alpha i3 antibody, but not by injection of anti-G alpha i1/G alpha i2 antibody. 6. The above results indicate that Gi mediates the SRIF effects on inward rectifier K+ currents. However, different subtypes of Gi are involved in the brain neurones and in the endocrine cells: Gi2 in locus coeruleus neurones and Gi3 in AtT-20 cells.

Animals↗

Effect of bezafibrate on hypercoagulability assessed by fluorogenic prothrombin time in hyperlipidemic patients with non-insulin-dependent diabetes mellitus.

We investigated the usefulness of the fluorogenic prothrombin time (FPT) for detection of hypercoagulability and its association with hyperlipidemia in 19 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 10 healthy control subjects, compared with plasma levels of fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and D-dimer. We also evaluated the effect of bezafibrate on hypercoagulability in 10 hyperlipidemic NIDDM patients. The plasma levels of FPT and fibrinogen were significantly higher in hyperlipidemic NIDDM patients than in normolipidemic NIDDM patients and controls. Plasma levels of PAI-1 and D-dimer were significantly higher in normolipidemic and hyperlipidemic NIDDM patients compared with controls. The FPT was correlated with the HbA1c, the body mass index, and levels of total cholesterol, fibrinogen and PAI-1. Six-months therapy with bezafibrate reduced the levels of FPT, triglycerides and basal insulin, but did not alter levels of fibrinogen, PAI-1 and D-dimer. Our results showed that the FPT was useful for detection of hypercoagulability and evaluation of the effect of drugs. The increased FPT in patients with NIDDM suggested that hypercoagulability was present in association with hyperlipidemia.

Aged↗

Contribution of the hydrophobic effect to the stability of human lysozyme: calorimetric studies and X-ray structural analyses of the nine valine to alanine mutants.

To clarify the contribution of the hydrophobic effect to the conformational stability of human lysozyme, a series of Val to Ala mutants were constructed. The thermodynamic parameters for the denaturation of these nine mutant proteins were determined using differential scanning calorimetry (DSC), and the crystal structures were solved at high resolution. The denaturation Gibbs energy (delta delta G) and enthalpy (delta delta H) values of the mutant proteins ranged from +2.2 to- 6.3 kJ/mol and from +7 to -17 kJ/mol, respectively. The structural analyses showed that the mutation site and/or the residues around it in some proteins shifted toward the created cavity, and the substitutions affected not only the mutations site but also other parts far from the site, although the structural changes were not as great. Correlation between the changes in the thermodynamic parameters and the structural features of mutant proteins was examined, including the five Ile to Val mutant human lysozymes [Takano et al. (1995) J. Mol. Biol. 254, 62-76]. There was no simple general correlation between delta delta G and the changes in hydrophobic surface area exposed upon denaturation (delta delta ASAHP). We found only a new correlation between the delta delta G and delta delta ASAHP of all of the hydrophobic residues if the effect of the secondary structure propensity was taken into account.

Alanine↗

Random migration of polymorphonuclear leukocytes induced by GM-CSF involving a signal transduction pathway different from that of fMLP.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced random migration of human polymorphonuclear leukocytes (PMNs) but not chemotaxis. Chemoattractants such as N-formyl-methionyl-leucyl-phenylalanine (fMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8) induced both random migration and chemotaxis. Other inflammatory cytokines, including granulocyte colony-stimulating factor (G-CSF), interleukin 1alpha (IL-1alpha), and tumor necrosis factor alpha (TNF-alpha), did not induce either movement. One-minute exposure of PMNs to GM-CSF was sufficient for the induction of random migration, whereas fMLP-induced random migration required continued presence of fMLP. Inhibitors of phosphatidylinositol 3-kinase (PI3-K), protein kinase C (PKC), and protein tyrosine kinase (PTK) had no effect on random migration induced by GM-CSF, whereas fMLP-induced movements were partially inhibited by PTK inhibitors but not by inhibitors of PI3-K inhibitors nor PKC inhibitors. Myosin light chain kinase inhibitors inhibited movements of PMNs induced by both GM-CSF and fMLP. These findings also imply that some aspects of the signal transduction pathway of GM-CSF leading to random migration is different from that of fMLP. Our findings suggest that cell movements are controlled through diverse signal transduction systems.

Androstadienes↗

Leukotriene B4-activated human endothelial cells promote transendothelial neutrophil migration.

We explored the effect of leukotriene B4 (LTB4) on endothelial cells in LTB4-induced transendothelial migration (TEM) of neutrophils as an in vitro model of neutrophil extravasation. Chemotactic response of human neutrophils to LTB4 was significantly lower than that in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP), whereas the extent of TEM in response to LTB4 was significantly higher than that to fMLP. The study on random migration induced by LTB4 and fMLP also showed similar results, which indicated that LTB4 might affect the human umbilical cord vein endothelial cell (HUVEC) barrier. Neutrophil TEM was induced by pretreatment of HUVEC monolayer with LTB4 but not with fMLP. Treatment of endothelial cells by ONO-4057, a LTB4 receptor antagonist, abolished the effect of LTB4 almost completely whereas neutrophils treated with ONO-4057 could transmigrate through HUVEC treated with LTB4. These findings indicated that LTB4 could induce neutrophil TEM by acting on HUVEC.

Cell Movement↗

Length of transplanted small bowel required for adequate weight gain in rats.

Progress has been made toward developing a clinically successful small-bowel transplant procedure, but there has been little research concerning the functional aspects of the transplanted small bowel. Using a rat model, our study examined the length of transplanted small bowel required to provide adequate weight gain. The rats were divided into six groups; groups 1 and 2 were considered controls. Group 1 (n = 6) underwent a gastrostomy. Group 2 (n = 3) underwent a jejunoile-ectomy followed by re-establishment of intestinal continuity and anastomosis of the native proximal small bowel to an abdominal stoma and the distal portion to the ascending colon. Groups 3 (n = 5), 4 (n = 4), 5 (n = 5), and 6 (n = 4) underwent small-bowel transplantation, receiving 100%, 50%, 25%, and 15% transplants, respectively. The donor small-bowel anastomoses were the same as the native small-bowel anastomoses in group 2. All of the rats began to produce stool within 4 days of becoming dependent upon the transplanted small bowel. By the end of postoperative week 4, there was no significant difference between the percentages of preoperative body weight in groups 1-4 (range 125.7%-130.0%). Although the weight gain in group 5 was significantly less than that in groups 1-4 (P < 0.05), it was adequate (111.8%); group 6 animals lost weight (94.7%). It is concluded that a 50% or more small-bowel transplant with or without an ileocecal valve provides ample weight gain; minimally adequate weight gain is achieved by a 25% transplant without an ileocecal valve; and the graft begins to function soon after transplantation.

Animals↗

Anti-granulocyte antibody suppression of active and passive anaphylactic shock in WBB6F1-W/Wv mice.

Our previous study revealed that anaphylactic shock can be produced in WBB6F1-W/Wv (abbreviated as W/Wv) mice. Because they are congenitally deficient in mast cells, we are certain that some other cell types are involved as mediator sources. In the present study, with the aim of examining the role of circulatory granulocytes, the effect of monoclonal antibody to a mouse granulocyte antigen, Gr-1, upon active and passive anaphylactic shock was tested in W/Wv mice using several mast cell-bearing strains as references. An intravenous injection of 40 micrograms of anti-granulocyte antibody one day before the antigen challenge produced a marked decrease in neutrophils and nearly complete abolition of lethal shock in W/Wv mice regardless of the sensitizing method. Both prevention of shock and reduction of neutrophils lasted for three days after the treatment with the antibody but not for six days. From these results, a reasonable conclusion would be that circulating Gr-1+ cells (predominantly composed of neutrophils) are the major mediator source. Reference experiments using mast cell-bearing strains revealed that the suppressive effect of anti-granulocyte antibody was also observed against active anaphylactic shock in C3H/HeN mice but not against active and passive anaphylactic shock in the other mice.

Anaphylaxis↗

Estrogen and parathyroid hormone regulate insulin-like growth factor binding protein-4 in SaOS-2 cells.

The effect of 17beta-estradiol and parathyroid hormone (PTH) on the expression of insulin-like growth factor-binding protein-4 (IGFBP-4) messenger RNA (mRNA) was studied in the cultured human osteoblast-like SaOS-2 cells. Treatment of SaOS-2 cells with PTH for 3 h caused 3.3-fold increase in IGFBP-4 mRNA levels which was determined by reverse transcription-polymerase chain reaction. 17beta-Estradiol had no effect on either the stimulation of mRNA level by PTH or the basal level. Together with our previous report that 17beta-estradiol inhibits the PTH-induced reduction of IGFBP-4 proteolysis in these cells, the results obtained may help to explain the mechanisms of determining IGFBP-4 availability by systemic hormones in osteoblast cells.

Blotting, Western↗