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Biomedical subjects

K Takao

Publications and source records attributed to K Takao.

At least 19 recordsLinked to original sources
PubMed2005

Gas-phase ion/molecule reactions in C5F8.

Gas-phase ion-molecule reactions in octafluorocyclopentene (C5F8) were studied with a pulsed electron beam mass spectrometer. When a few Torr of major gas, CH4, Ar, or N2, containing approximately 10 mTorr C5F8 was ionized by 2 keV electrons, C5F8+, C5F7+, C4F6+, C4F5+, and C3F3+ were formed as major fragment ions. The interaction between those ions and C5F8 is found to be a weak electrostatic interaction. The cation...C5F8 bonding energies are around 10 kcal/mol, which were reproduced well by (U)B3LYP/6-311+G(d) calculations. The proton affinity of C5F8 (=148.6 kcal/mol by B3LYP/6-311+G(d)) was found to be smaller than that of C2H4 (=162.8 kcal/mol). In the negative mode of operation, the intense signal of C5F8- was observed during the electron pulse. This indicates that C5F8 has a positive electron affinity (1.27 eV by (U)B3LYP/6-311+G(d)). The C5F8- ion was quickly converted to a complex C10F16-. This complex did not react further with C5F8 down to 170 K. The theoretical calculation revealed that a C5F7-F-...C5F8 interaction mode in (C5F8)2- was converted to a C5F7*...C5F9- one via fluoride-ion transfer. The F- ion was found to form a strong covalent bond with C5F8, but the interaction in F-(C5F8)- - -C5F8 is a weak electrostatic interaction due to the charge dispersal in F-(C5F8). The halide ions except F- interact with C5F8 only weakly. Thermochemical stabilities for the cluster ions I-(CH3I)n (n = 1, 2) were also determined.

Journal Article↗
PubMed2004

Hyperbaric oxygen therapy in orthopedic conditions.

As is well known, the origins and development of hyperbaric medicine are closely tied to the history of diving medicine. Our HBO2 studies stemming from diving medicine date back to 1972. We concentrated our early basic research on dysbaric osteonecrosis. There are now good indications that HBO2 is helpful in a variety of orthopedic conditions. However, hyperbaric medicine in orthopedics is still relatively new and some aspects of it remain controversial.

Congresses as Topic↗
PubMed2003

In vitro expansion of human basophils by interleukin-3 from granulocyte colony-stimulating factor-mobilized peripheral blood stem cells.

BACKGROUND: A number of studies support the belief that human basophils play an important role in allergic inflammation. The exact mechanism of basophil activation at the site of allergic inflammation, however, has not been well understood, mainly due to their low number in blood and difficulty in obtaining a sufficient number of highly purified basophils for investigation. OBJECTIVE: The purpose of this study is to expand human basophils in vitro with high yield and purity by culturing peripheral blood stem cells (PBSCs). METHODS: We collected PBSC-rich mononuclear cells containing CD34+ cells (0.15-4.9%) by leukapheresis from patients with malignant lymphoma and lung cancer during haematopoietic recovery after chemotherapy plus granulocyte colony-stimulating factor-induced mobilization. PBSC-rich mononuclear cells were cultured in the presence of IL-3. RESULTS: When PBSC-rich mononuclear cells containing more than 1% of CD34+ cells were cultured, 20.0-83.3% of the cells, mostly with a yield of >10%, were metachromatic cells after 3 weeks of culture. These cells resembled mature peripheral blood basophils morphologically when examined by light and electron microscopy. Flow cytometric analysis showed that they expressed both FcepsilonRI and FcgammaRII. FcepsilonRI cross-linking resulted in intracellular calcium mobilization, histamine release and synthesis of cysteinyl leukotrienes. The intracellular histamine content and the release of these chemical mediators triggered by anti-IgE antibodies were comparable to those of peripheral blood basophils. CONCLUSION: These findings suggest that PBSC-derived basophils expanded in vitro are morphologically and functionally mature and will be a useful tool for the analysis of basophil functions.

Adolescent↗
PubMed2001

Highly diastereoselective 1,4-addition of an organocuprate to methyl alpha-D-gluco-, alpha-D-manno-, or alpha-D-galactopyranosides tethering an alpha,beta-unsaturated ester. Novel asymmetric access to beta-C-substituted butanoic acids.

The 1,4-addition of magnesium divinylcuprate prepared from vinylmagnesium bromide and cuprous bromide to some 4-O-crotonyl derivatives of methyl alpha-D-glucopyranoside proceeds with a high level of diastereochemical induction, providing the adduct in good-to-excellent yields. Other organocuprates also serve as effective carbon nucleophiles for the 1,4-addition. Removal of the carbohydrate moiety from each adduct afforded a variety of beta-C-substituted butanoic esters in remarkable enantiomeric excess. The 1,4-addition of the same cuprate to some methyl alpha-D-manno- or alpha-D-galactopyranosidic substrates in which a crotonyl group was incorporated, each at 3-OH, was also investigated. The reverse pi-facial attack of the cuprate was observed when some D-manno-type substrates were subjected to 1,4-addition conditions similar to those used for the D-gluco-type substrates. Furthermore, some D-galacto-type substrates provided 1,4-adducts with higher diastereoselectivities.

Butyrates↗
PubMed2001

Importance of the 3' untranslated region of ornithine decarboxylase mRNA in the translational regulation of the enzyme.

Translational regulation of ornithine decarboxylase (ODC), which catalyses the first step in the biosynthesis of polyamines, appears to be an important mechanism in the strong feedback control as well as in the hypotonic induction of the enzyme. However, the exact mechanisms are not yet understood. The ODC mRNA has long 5' and 3' untranslated regions (UTRs) which may be involved in the translational control of the enzyme. In the present study we have used a series of stable transfectants of Chinese Hamster ovary cells expressing ODC mRNAs with various truncations in the 5' and 3' UTRs to investigate the importance of these regions. It is demonstrated that neither the 5' UTR nor the 3' UTR appears to be involved in the polyamine-mediated feedback control of ODC synthesis. The hypotonic induction of ODC, on the other hand, was shown to be highly dependent on the presence of the 3' UTR, but not on the 5' UTR, of ODC mRNA. Cells expressing ODC mRNAs lacking the 3' UTR showed no, or only a very slight, induction of ODC whether the 5' UTR was present or not, whereas the cell lines expressing ODC mRNAs containing the 3' UTR (with or without the 5' UTR) markedly induced ODC after a hypotonic shock. The present finding of a role for the ODC mRNA 3' UTR in the hypotonic induction of ODC is the first demonstration of a specific effect of the 3' UTR in the regulation of ODC.

3' Untranslated Regions↗
PubMed2001

Isolation of chymase complexed with physiological inhibitor similar to secretory leukocyte protease inhibitor (SLPI) from hamster cheek pouch tissues.

A low molecular weight protein complexed with chymase was isolated from hamster cheek pouch tissues. This protein had an apparent molecular mass of about 10 kDa on SDS-PAGE and the N-terminal sequence showed some homology to secretory leukocyte protease inhibitor (SLPI), which is known as the predominant inhibitor of neutrophil elastase and cathepsin G. Remarkably enhanced inhibition of chymase activity was achieved in the presence of heparin, indicating that the functional property was also similar to SLPI. These findings suggest that this SLPI-like protein is a candidate for a physiological inhibitor of chymase.

Amino Acid Sequence↗
PubMed2001

Differential effect of Fyn tyrosine kinase deletion on offensive and defensive aggression.

Fyn tyrosine kinase is highly expressed in the limbic system and mice lacking Fyn tyrosine kinase showed increased fearfulness in a variety of tests for anxiety-related behaviors. To investigate the possible role of Fyn tyrosine kinase in aggression, we assessed the aggressive behaviors of the mice lacking the Fyn tyrosine kinase using the resident-intruder and restraint-induced target biting paradigms. The percentage of Fyn-deficient mice that attacked an inanimate target in a restraint tube was higher than that of the control mice. On the contrary, in the resident-intruder paradigm, the percentage of Fyn-deficient mice that attacked the intruder was lower and the Fyn-deficient mice showed a longer latency to attack an intruder. These results suggest a distinct role of Fyn tyrosine kinase in enhancing the offensive aggression and decreasing the defensive aggression. A possible influence of anxiety-phenotype of the Fyn-deficient mice on their abnormal aggressive behavior was discussed.

Aggression↗
PubMed2001

Relation between body composition and age in healthy Japanese subjects.

OBJECTIVE: To describe the relation between body composition and age measured by dual-energy X-ray absorptiometry (DXA) in healthy Japanese adults. DESIGN: Cross-sectional study. SUBJECTS AND MEASUREMENTS: The subjects were 2411 healthy Japanese adults (males 625, females 1786, age 20--79 y) who attended the Fukuoka Health Promotion Center, Fukuoka, Japan for health check-up. Body composition was determined by DXA (QDR-2000, Hologic) for the whole body and three anatomical regions of arms, legs and trunk. RESULTS: The mean values of body mass index (BMI) and percentage fat mass (%FM) were 23.2+/-3.1 (s.d.) kg/m(2) and 21.8+/-6.8% for males and 22.1+/-3.3 kg/m(2) and 32.0+/-7.5% for females, respectively. For males, curvilinear relations with the peaks in their forties or fifties were seen for the variables associated adiposity, ie BMI, waist and hip circumference, waist-hip ratio, total or regional fat mass (FM), %FM and ratio of trunk FM to leg FM. For females, most of these variables increased linearly in older subjects. Lean mass (LM), bone mineral content (BMC) and bone mineral density (BMD) of the whole body and appendicular LM were relatively constant until the forties and then decreased in both sexes. The rates of decrease in the total or appendicular LM were larger for males than for females, whereas those in BMC or BMD were larger for females than for males. CONCLUSIONS: This study presents the first detailed data on body composition in Japanese, which may be useful when comparing with populations of different racial and ethnic backgrounds and studying ill subjects.

Absorptiometry, Photon↗
PubMed2001

Comparison of sevoflurane with isoflurane for rapid mask induction in midazolam and butorphanol-sedated dogs.

Rapid mask induction can be a useful induction technique for veterinary patients, although it is often accompanied by exaggerated excitement responses in unpremedicated animals (Mutoh et al.: Jpn. J. Vet. Anesth. Surg. 26, 109-116; J. Vet. Med. Sci. 57, 1007-1013; J. Vet. Med. Sci. 57, 1121-1124; 1995). The aim of this study was to compare sevoflurane with isoflurane for rapid mask induction in six dogs sedated by a combination of midazolam (0.1 mg/kg) and butorphanol (0.2 mg/kg). Induction with sevoflurane (5%, 2.4 minimum alveolar concentration [MAC]) in O2 resulted in shorter time to loss of the palpebral reflex, negative tail clamp response, and successful intubation than with isoflurane (3%, 2.4 MAC) in O2. There were no changes in heart rate or mean arterial blood pressure during induction with sevoflurane, whereas an increase in heart rate was observed in dogs induced with isoflurane. A decrease in respiratory rate compared with the pre-induction rate was observed during induction, and associated mild respiratory acidosis, characterized by an increase in arterial PCO2, was measured at the end of the induction period in both induction groups. None of the animals had episodes of induction-related complications. These results suggest that both sevoflurane and isoflurane produce a smooth onset of induction in midazolam and butorphanol-sedated dogs. Sevoflurane is a more suitable for rapid mask induction than isoflurane since it provides faster induction associated with a lower blood/gas partition coefficient.

Anesthesia, Inhalation↗
PubMed2001

Association of serum tumour necrosis factor-alpha with serum low-density lipoprotein-cholesterol and blood pressure in apparently healthy Japanese women.

1. The pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha is considered to be involved in the development of atherosclerosis by inducing local inflammatory responses in the vascular wall. Because TNF-alpha is also known to affect lipid and glucose metabolism, the association between the circulating concentration of TNF-alpha and atherogenic risk factors was examined in 82 apparently healthy Japanese women (aged 19-69 years; mean age 48.5 years). 2. The mean (+/-SD) serum TNF-alpha concentration was 2.7+/-0.9 pg/mL (range 1.4-5.9 pg/mL). The TNF-alpha concentration showed significant correlations with age (r = 0.28; P = 0.01), body mass index (r = 0.27; P = 0.01), the waist-hip ratio (r = 0.41; P = 0.0002), percentage body fat (r = 0.30; P = 0.006), systolic (r = 0.32; P = 0.004) and diastolic (r = 0.24; P = 0.03) blood pressure, total cholesterol (r = 0.27; P = 0.02) and low-density lipoprotein-cholesterol (LDL-C; r = 0.36; P = 0.001), while the correlations with high-density lipoprotein-cholesterol (r = -0.20; P = 0.08) and insulin resistance estimated by the homeostasis model assessment (HOMA(IR); r = 0.16; P = 0.15) were not statistically significant. 3. When adjusted for age and menopause, TNF-alpha was significantly associated with systolic blood pressure (r = 0.25; P = 0.02) and LDL-C (r = 0.27; P = 0.02). The association between TNF-alpha and LDL-C remained significant when adjustment was made for age, menopause and the waist-hip ratio (r = 0.24; P = 0.03). 4. Our results indicate that TNF-alpha may play a role in modulating blood pressure and LDL-C.

Adult↗
PubMed2001

[Orchiectomy for tuberculous epididymitis: a report of two cases with intractable to antituberculosis treatment].

This paper describes two cases with tuberculous epididymitis. The first case was a 69-year-old man who was admitted to our hospital because of ulceration or right scrotum. Physical examination revealed a hard, rounded, a little bigger than egg-sized mass in the right scrotum. The second case was a 40-year-old man who was admitted to our hospital because of cough, fever and body weight loss. He was treated for pulmonary tuberculosis with isoniazid, rifampicin, streptomycin and pyrazinamide. Six months after admission, he complained of a painless swelling of the right scrotum. Physical examination revealed a hard, rounded, more than egg-sized mass in the right scrotum. Right orchiectomy was performed in these two cases, and they were cured.

Adult↗
PubMed2000

A region of the sulfonylurea receptor critical for a modulation of ATP-sensitive K(+) channels by G-protein betagamma-subunits.

To determine the interaction site(s) of ATP-sensitive K(+) (K(ATP)) channels for G-proteins, sulfonylurea receptor (SUR2A or SUR1) and pore-forming (Kir6.2) subunits were reconstituted in the mammalian cell line, COS-7. Intracellular application of the G-protein betagamma2-subunits (G(betagamma)(2)) caused a reduction of ATP-induced inhibition of Kir6.2/SUR channel activities by lessening the ATP sensitivity of the channels. G(betagamma)(2) bound in vitro to both intracellular (loop-NBD) and C-terminal segments of SUR2A, each containing a nucleotide-binding domain (NBD). Furthermore, a single amino acid substitution in the loop-NBD of SUR (Arg656Ala in SUR2A or Arg665Ala in SUR1) abolished the G(betagamma)(2)-dependent alteration of the channel activities. These findings provide evidence that G(betagamma) modulates K(ATP) channels through a direct interaction with the loop-NBD of SUR.

ATP-Binding Cassette Transporters↗
PubMed1999

Lack of effect of carbohydrate depletion on some properties of human mast cell chymase.

Human chymase from vascular tissues was purified to homogeneity by heparin affinity and gel filtration chromatography. Treatment of human chymase with endoglycosidase F resulted in cleavage of the carbohydrate moiety yielding a deglycosylation product that did not lose its catalytic activity. This enzymatic deglycosylation product was enough to explore possibilities that N-glycan might modify some properties of human chymase. Substrate specificity, optimum pH and the elution profile from the heparin affinity gel were not affected by the deglycosylation. Only a slight but significant difference was observed in the Km value for conversion of angiotensin I to angiotensin II. Other kinetic constants such as kcat were not influenced. The kinetics of conversion of big endothelin-1 to endothelin-1(1-31) were not significantly affected. The deglycosylated human chymase was more susceptible to deactivation under alkaline pH and thermal stress. Even at physiological temperature and pH, the activity of glycosylated human chymase was more stable. From these results, it appears that the N-glycan of human chymase contributes to the stability of this enzyme but not to its functional properties.

Carbohydrates↗
PubMed1999

Preparation and usefulness of some fluorogenic substrates for assay of arginyl-tRNA-protein transferase by HPLC.

A series of fluorescent substrates and products was prepared and evaluated for the assay of arginyl-tRNA-protein transferase (arginyltransferase) activity by HPLC. Since N-aspartyl-N'-dansylamido-1,4-butanediamine (Asp(4)DNS) was the most suitable substrate of the compounds tested, which had a three-, four-, or five-methylene-chain interval between Asp or Glu and DNS, the following enzymatic studies were focussed on Asp(4)DNS and its product, N-arginylaspartyl-N'-dansylamido-1,4-butanediamine (ArgAsp(4)DNS). The apparent Km value for Asp(4)DNS was calculated to be 30 microM using a hydroxyapatite-treated arginyltransferase preparation from hog kidney, which was free from any enzyme that might decompose the two compounds. The present HPLC method was shown to be advantageous in reliability and sensitivity compared to the available isotope paper disk method using the hydroxyapatite-treated enzyme preparation and in applicability to crude samples examined using a DEAE-treated arginyltransferase preparation and 105,000g supernatant (105S) from hog kidney. Stepwise elimination of Arg and Asp from ArgAsp(4)DNS was observed with the two crude enzyme solutions, and the elimination of Arg was suppressed by the addition of bestatin, suggesting the participation of certain aminopeptidases. Although Asp(4)DNS was decomposed significantly with 105S, an incubation-time-dependent linear elevation of ArgAsp(4)DNS was maintained for 5 min in the presence of bestatin. Furthermore, an addition-recovery test of the DEAE-treated enzyme preparation for the 105S assured accurate determination of arginyltransferase activity in the 105S under the tentatively established conditions. The present HPLC method, which permits the simultaneous determination of 4-dansylamidobutylamine, Asp(4)DNS, and ArgAsp(4)DNS, was advantageous in measuring arginyltransferase activity and detecting the presence of unfavorable enzyme(s) in samples to ensure accurate determination.

Aminoacyltransferases↗
PubMed1999

Comparison of sedative effects of medetomidine-midazolam, acepromazine-butorphanol and midazolam-butorphanol in dogs.

Sedative effects of medetomidine at 20 micrograms/kg and midazolam at 0.3 mg/kg (MM), acepromazine at 0.05 mg/kg and butorphanol at 0.2 mg/kg (AB), and midazolam at 0.1 mg/kg and butorphanol at 0.2 mg/kg (MB) were compared in dogs. All dogs given MM were laterally recumbent within 11 min of the administration of the drugs, and this combination also induced deep sedation accompanied by analgesia and muscle relaxation, and strongly depressed arousal reactions to external stimuli. However, undesirable effects such as bradycardia and decreased respiration were also observed in dogs given MM. Six of seven dogs given AB were laterally recumbent within 16 min of the administration of the drugs, and this combination induced relatively deep sedation but only a mild depression of arousal reactions to external stimuli. MB induced mild or moderate sedation with relatively large differences in effects among individuals. The recovery from sedation in each group was smooth and total recovery times were not significantly different.

Acepromazine↗
PubMed1999

Comparison of cardiopulmonary effects of medetomidine-midazolam, acepromazine-butorphanol and midazolam-butorphanol in dogs.

Cardiopulmonary effects of intramuscular administration of medetomidine-midazolam at 20 micrograms/kg and 0.3 mg/kg, respectively (MM), acepromazine-butorphanol at 0.05 and 0.2 mg/kg, respectively (AB), and midazolam-butorphanol at 0.1 and 0.2 mg/kg, respectively (MB), were compared in dogs. MM produced relatively large cardiovascular changes such as bradycardia, hypertension, a decrease in cardiac output and vasoconstriction. AB produced moderate cardiovascular changes. Hypotension was observed within 5 min after administration and the mean arterial blood pressure decreased by 30% at 20 min after administration. MB produced decreases in arterial blood pressure and cardiac output, but these changes were small and, of the combinations evaluated in this study, MB had the mildest cardiovascular effects.

Acepromazine↗
PubMed1999

Effect of cautery with irrigation forceps on the remnant liver after hepatectomy in rats.

Monopolar cautery with irrigation forceps (CIF) was devised for use in liver resection that does not require occlusion of inflow to the remnant liver. However, a high power output is required to divide the hepatic parenchyma which boils the irrigation water. This study was performed to investigate the effects of using CIF on the hepatic parenchyma. Histologic and biochemical examination was performed in rats which had undergone hepatectomy using the CIF, irrigating bipolar (IB), Pringle's maneuver with blunt dissection (group P), or a sham operation. A greater cautery distance was obtained with the CIF than the IB. There was no significant difference in the remnant liver function after the 1st postoperative day in any of the groups. CIF is an effective instrument for anatomic or nonanatomic hepatic resection.

Animals↗