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Biomedical subjects

K Takamura

Publications and source records attributed to K Takamura.

At least 37 records · Page 2Linked to original sources
PubMed1996

Determination of synephrine enantiomers in food and conjugated synephrine in urine by high-performance liquid chromatography with electrochemical detection.

Determination of synephrine enantiomers was made with HPLC with electrochemical detection using a chiral ligand-exchange column (Sumichiral OA-6000). The calibration curve for each enantiomer showed good linearity (r = 0.999) at 1.0-500 pmol injected with a detection limit of 1.0 pmol (signal-to-noise ratio (S/N) = 3). Relative standard deviation (RSD) was 1.8% at 50 pmol d-synephrine and 1.6% at 50 pmol l-synephrine. The contents of synephrine enantiomer in food such as Citrus unshiu fruit, orange juice, and marmalade were determined. The present method was also used to determine conjugated synephrine enantiomers in urine following the ingestion of C. unshiu pulp. l-Synephrine in fruit was converted to the conjugated form of synephrine, and l-synephrine underwent chiral inversion to d-synephrine in vivo.

Adult↗
PubMed1996

Sensitive densitometry for the determination of platelet-activating factor and other phospholipids in human tears.

A sensitive TLC method is reported for the determination of the platelet-activating factor (PAF) and other phospholipids in human tears. Tear samples absorbed on filter-paper were subjected to diatomite column extraction with chloroform-methanol. The eluent containing phospholipids was spotted on a silica gel plate. After removing lipids other than phospholipids by pre-development with hexane-diethyl ether (4 + 1 v/v), individual phospholipid separation was carried out by development with chloroform-methanol-water (65 + 35 + 7 v/v). Phospholipase C and then alkaline phosphatase solutions were sprayed on the TLC plate at 45 degrees C to liberate phosphate from each phospholipid. By spray application of a mixture of ammonium molybdate and Malachite Green, the liberated phosphates appeared as blue-green spots of molybdophosphate-Malachite Green aggregate on a yellow-brown background. The absorbance of each spot on the plate was measured at 620 nm with a densitometer. The peak area was found to be linearly related to PAF content in the range 2-100 pmol per spot, the RSD being 2% (n = 7). Approximately 86% of standard PAF added to tears was recovered. By this method, lysophosphatidylcholine (lysoPC), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in human tears could also be detected with high sensitivity. Each phospholipid in healthy human tears showed a nearly constant content; PAF, lysoPC, PC and PE were present at levels of 26.2, 42.3, 10.0 and 19.7%, respectively.

Chromatography, Thin Layer↗
PubMed1996

Motor and sensory disability has a strong relationship to induction dose of thiopental in patients with the hypertropic variety of Charcot-Marie-Tooth syndrome.

In a prospective study, we determined the anesthetic induction dose of thiopental and the clinical variables influencing the appropriate induction dose of thiopental in 20 patients with the hypertrophic variety of Charcot-Marie-Tooth syndrome (CMT). As controls we chose 50 patients without CMT. Motor disturbance was evaluated in terms of muscle weakness of the distal lower and upper extremities. We examined sensory disturbance by evaluating loss of sensation in the index finger and great toe. The preinduction cardiac output was measured by echocardiography. Anesthesia was induced with repeated injections of 50 mg thiopental. The minimum induction dose of thiopental (MID) was confirmed when the eyelash reflex ceased. We maintained anesthesia with enflurane and nitrous oxide. The 95% confidence interval of the MID in patients used as the controls was 2.5-4.9 mg/kg. The MID in 11 patients with CMT was less than 2.5 mg/kg. MIDs in the patients with CMT were significantly smaller than those of the control patients (P < 0.0001). Also we found a strong relationship between the MID and the severity of both motor and sensory disturbances (P = 0.003 and 0.002, respectively). There was no relationship between the MID and other clinical variables, such as age, gender, inherited type, body weight, and preinduction cardiac output. Because delay in the recovery from anesthesia can be caused by an inappropriate dose of thiopental in CMT patients in whom motor and sensory function is seriously impaired, the dose of thiopental probably should be reduced and based on the individual patient's response.

Adolescent↗
PubMed1996

[Toxic shock-like syndrome with Streptococcus pyogenes in a pleural effusion].

A 58-year-old woman was admitted to the hospital because of fever and hypotension. That night, shock developed. On the second hospital day, a chest roentgenogram showed retention of pleural fluid and the group A-beta hemolytic organism Streptococcus pyogenes was detected in the effusion. The toxic shock-like syndrome was diagnosed. The patient recovered with artificial ventilation, administration of antibiotics, and blood purification. In this patient, the type of pyrogenic exotoxin was B + C.

Female↗
PubMed1995

Determination of barnidipine in human serum and dog plasma by HPLC with electrochemical detection.

Barnidipine is a 1,4-dihydropyridine calcium antagonist. HPLC was conducted on a polybutadiene coated alumina column using an alkaline mobile phase and an electrochemical detector to determine the content of this drug in serum and plasma. A good linear relationship between barnidipine concentration and peak height was found in 5-500 ng/ml with a correlation coefficient of 0.998. The detection limit was 1 ng/ml. The within-day and day-to-day variations were examined for control human serum. Relative standard deviation of within-day assay for serum spiked with 10 ng/ml barnidipine.HCl was 6.9% and the recovery was 104%. A pharmacokinetic study was made in which the time course of barnidipine in dog plasma was followed.

Animals↗
PubMed1994

Evaluation of carcinogenicity and chronic toxicity associated with orthopedic implants in mice.

The carcinogenicity and chronic toxicity of 316L stainless steel, nickel, Ti-6A1-4V, hydroxyapatite (HA)-coated Ti-6A1-4V, aluminum oxide containing yttrium oxide, and zirconium oxide containing yttrium oxide were evaluated by implanting solid rods of each material in the thigh muscle of C57BL/6N mice for 24 months. Nickel alloy showed high carcinogenic and toxic potencies, whereas other materials showed no evidence of them. Tumors retaining nickel alloys were malignant fibrous histiocytoma or fibrosarcoma. In some cases, lymphomata that seemed to develop spontaneously were found around the implants because lymphocytes were known to accumulate in chronic inflammatory lesions, and this phenomenon also might be applied to lymphoma.

Alloys↗
PubMed1994

[Spectrophotometric determination of uric acid in serum using a titanium (IV)-porphyrin complex].

Aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium (IV) complex, a Ti-TPyP reagent, was found to be very useful for the spectrophotometric determination of hydrogen peroxide. The reagent (lambda max 432 nm) reacts with hydrogen peroxide to form a monoperoxocomplex, resulting in a significant decrease of the absorbance at 432 nm. The decrease (delta A) in absorbance was proportional to the concentration of hydrogen peroxide. The Ti-TPyP reagent was successfully applied to the assay of uric acid in the serum, using uricase to produce hydrogen peroxide through enzymatic oxidation. Using only 5 microliters serum, a linear relationship was obtained between delta A and uric acid concentration in the serum ranging from 5 x 10(-6) to 1 x 10(-3) M. The apparent molar delta A of uric acid was 2.2 x 10(5) M-1 cm-1. The relative standard deviation of repeated runs (n = 8) was 2.8% at 3.77 x 10(-4) M uric acid. The analytical recovery of uric acid (5 x 10(-4) M) added to the serum was 96.8 to 105.0%. No pre-concentration and deproteinization were required to determine uric acid in the serum by the present method because of the high sensitivity and selectivity of the Ti-TPyP reagent for hydrogen peroxide.

Gout↗
PubMed1994

[Densitometric quantitation of platelet activating factor and other phospholipids in human saliva using enzyme reaction on a silica plate].

A sensitive quantitative analysis by thin layer chromatography was developed for the determination of platelet activating factor (PAF) and other phospholipids in human saliva. The saliva sample (0.6 ml) was pretreated by diatomite column extraction with chloroform-methanol (95:5, v/v). The extract (20 microliters) was spotted on a TLC plate. The mobile phase was chloroform-methanol-water (65:35:7, v/v). The development proceeded until the mobile phase front reached 8 cm from the spotted point, this process usually required 30 min. After development, phospholipase C and alkaline phosphatase solutions were sprayed on the TLC plate at 45 degrees C to hydrolyze phospholipids. By spraying a mixture of ammonium molybdate and Malachite Green, the produced phosphate was changed to molybdophosphate-Malachite Green aggregate, which gave a blue green spot. The colored spots were scanned at 620 nm by chromatoscanner. A linear relationship was obtained between peak area and PAF concentration in the range from 2 to 100 pmol/spot with a relative standard deviation of 2% (n = 7). By this procedure, lysophosphatidylcholine, phosphatidylcholine and phosphatidylethanolamine in human saliva were also determined sensitively. PAF levels in the range from 40 to 300 ng/ml were found in normal human salivas. Although differences in the total amounts of phospholipids in saliva were found for each healthy volunteer and sampling time, the composition of phospholipids was proved to be virtually constant.

Densitometry↗
PubMed1993

Determination of trace amounts of phosphate in water after preconcentration using a thermally reversible polymer.

A method for concentrating and determining phosphate in natural waters, using poly(N-isopropylacrylamide) (PNIPAAm); a thermally reversible polymer, is described. Poly(N-isopropylacrylamide) is soluble in water below 31 degrees C but shrinks abruptly on heating above 31 degrees C, becoming insoluble. With phase separation of PNIPAAm from aqueous solution at 45 degrees C, a molybdophosphate-Malachite Green aggregate (P-Mo-MG), formed by reaction of a Mo-MG reagent, obtained by mixing ammonium molybdate and Malachite Green, was incorporated in PNIPAAm and the resulting solid stuck to the walls of the reaction vessel. After discarding the supernatant solution by decantation, the P-Mo-MG aggregate was dissolved in a small volume of methylcellosolve together with PNIPAAm. The absorbance (lambda max = 627 nm) was proportional to the concentration of phosphate with an apparent molar absorptivity of 2.6 x 10(4) m2 mol-1. This method makes possible the rapid determination of trace amounts of phosphate in water using simple apparatus. The detection limit was 2 nmol dm-3 of phosphate. The method was successfully applied to the determination of phosphate in natural water samples such as tap water, mineral water and rain water.

Acrylic Resins↗
PubMed1993

Isolation of reovirus type 3 from dogs with diarrhea.

Three virus strains were isolated in DK cell cultures inoculated with fecal specimens of dogs manifesting diarrhea. The isolates were identified as reoviruses on the basis of their biological and physico- chemical properties. They possessed reovirus type 3 antigenic specificity revealed by hemagglutination-inhibition and neutrarization tests with the reovirus prototype strains. It was suspected that the isolates were participated in this diarrheic cases.

Animals↗
PubMed1993

Induction of mucosal disease in cattle persistently infected with noncytopathic bovine viral diarrhea-mucosal disease virus by superinfection with cytopathic bovine viral diarrhea-mucosal disease virus.

Three head of cattle persistently infected with noncytopathic bovine viral diarrhea-mucosal disease virus (ncBVD-MDV) were superinfected naturally or experimentally with cytopathic bovine viral diarrhea-mucosal disease virus (cBVD-MDV). In the naturally superinfected case, one animal manifested pyrexia and severe diarrhea, and died without developing antibodies to cBVD-MDV. However, another animal survived with only continual slight anorexia and pyrexia, and developed strong resistance to the superinfected strain. In the experimental cases, induction of MD was unsuccessful in two persistently infected cattle when superinfected with cBVD-MDV antigenically heterologous for persistently infected ncBVD-MDV. They also developed antibodies to the cBVD-MDV strain with which they had been infected. After 6 months, these cattle were infected again with a cBVD-MDV strain different from that used in the previous experiment. One animal infected with this strain, which was antigenically homologous to the persistently infected strain, died after developing MD symptoms without developing antibodies to the infecting strain. It is suggested that the antigenic relationship between the persistent ncBVD-MDV and the superinfected cBVD-MDV was an important factor in developing MD.

Animals↗
PubMed1993

Protection against bovine leukemia virus infection by use of inactivated vaccines in cattle.

The protective effects of vaccines made from the viral materials of LK15 cell line (LK15 vaccine) or bat lung cell line (Bat2cl1; Bat vaccine) infected with bovine leukemia virus (BLV) were examined in cattle. Twelve cattle were vaccinated twice at 4-week interval then challenged 4 weeks after the second inoculation. Nine cattle vaccinated with the LK15 vaccine produced antibody to BLV-specific glycoprotein (gp), and the titers ranged from 1:16 to 1:64 by the agar gel immunodiffusion test. Four cattle challenged with 100 microliters (70 to 100 syncytia) of cow blood persistently infected with BLV were protected from infection. However, of the remaining 5 cattle challenged with 500 microliters of infected blood, only 2 were protected. Of the three cattle vaccinated with the Bat vaccine, gp antibody titers ranged from 1:8 to 1:64. Two of them were protected against the challenge with 100 microliters of infected blood. Two cattle protected against the challenge were rechallenged 32 weeks after the first vaccination and not protected. On the other hand, 2 animals protected against the challenge were revaccinated with the LK15 vaccine 32 weeks after the first vaccination. They protected against rechallenge. The results show that all cattle which had gp antibody titers of 1:16 or above were protective against challenge with 100 microliters of the infected blood.

Animals↗
PubMed1992

Cardiovascular anomalies in chick embryos produced by bis-diamine in dimethylsulfoxide.

N,N'-bis(dichloroacetyl)-1,8-octamethylenediamine(bis-diamin e) (100 micrograms) dissolved in dimethylsulfoxide (DMSO) was administered to early developing chick embryos (Hamburger-Hamilton stage 9-21) in order to clarify the teratogenic effects on the cardiovascular system and to determine whether bis-diamine interferes with the migration of neural crest cells. Of 346 cases, 154 (44.5%) survived. The incidence of cardiovascular anomalies was 149 out of 154 cases (96.8%). Infundibular ventricular septal defect, double outlet right ventricle, and persistent truncus arteriosus were the primary cardiac anomalies observed in this study. A high percentage of these anomalies were accompanied by hypoplasia of the right 6th aortic arch artery and persistent left 4th aortic arch artery. Particularly, administration of bis-diamine to chick embryos at stage 13 resulted in a high incidence of persistent truncus arteriosus (64.3%). Bis-diamine has been suspected to inhibiting the migration of neural crest cells. However, neural crest cells were observed in the tunica media of the great arteries and the truncal valves of persistent truncus arteriosus produced by bis-diamine in chimeric embryos at stage 13. Morphological changes such as cell death were not observed.

Abnormalities, Drug-Induced↗
PubMed1992

[Flow injection analysis for determination of choline-containing phospholipids by luminol chemiluminescence].

A sensitive flow injection analysis using luminol/peroxidase chemiluminescence was developed for the determination of choline-containing phospholipids in serum. Flow injection manifold was composed of two channel system with an enzyme column, in which phospholipase D was immobilized together with choline oxidase. The serum sample (5 microliters) was pretreated by Extrelut column (diatomite column) extraction with chloroform-methanol (95:5). The extract (20 microliters) was injected into a sample carrier at 38 degrees C and passed through the enzyme column, which converted phospholipid to choline and subsequently to hydrogen peroxide. Produced hydrogen peroxide was monitored by measuring the chemiluminescence intensity of luminol/peroxidase system at 5 degrees C. The response was linear against the amount of phospholipids ranging from 2 to 2000 pmol/test, and the relative standard deviation was less than 2%. In the determination of phospholipids in the serum, a correlation coefficient (r) between 4-aminoantipyrine/phenol and the proposed methods was found to be 0.983 (Y = 1.035X-6.2). The throughput rate was 15 samples/h.

Blood Chemical Analysis↗
PubMed1992

Field trials on a live bovine respiratory syncytial virus vaccine in calves.

Field trials were carried out in calves using a live bovine respiratory syncytial (BRS) virus vaccine prepared from the attenuated BRS virus, strain rs-52. Two hundred seventy-five and 353 calves were vaccinated intranasally and intramuscularly, respectively. No undesirable postvaccinal reactions were observed in the vaccinated calves. Of the serum neutralizing (SN) antibody negative calves 89.7% (26/29) and 92.8% (90/97) developed SN antibody 1 month after intranasal and intramuscular vaccination, respectively. Most of the calves having SN antibody titers of 1:1 or 1:2 at the time of vaccination showed a significant increase in SN antibody titer. About 70% and 90% of the calves vaccinated intranasally and intramuscularly, respectively, maintained SN antibody for 6 months after vaccination. In a field trial, a natural BRS virus infection occurred about 5 months after the start of the trial. Ten of the 16 unvaccinated control calves showed respiratory symptoms due to BRS virus infection. On the contrary, all of the 68 vaccinated calves exhibited no symptoms at all, indicating efficacy of the vaccine.

Animals↗
PubMed1990

Association of cephalic neural crest cells with cardiovascular development, particularly that of the semilunar valves.

The quail-chick chimera method was used to examine whether neural crest cells were associated with the formation of semilunar valves. From the metencephalon to somite 5, or from the otocyst to somite 3, left, right, or bilateral neural folds, including the neural crest, were transplanted. Among embryos used for the experiment, three into which left neural crest cells were transplanted, two into which right neural crest cells were transplanted, and two into which bilateral neural crest cells were transplanted had a morphologically normal heart. In these embryos, neural crest cells were found in all cusps of the aortic and pulmonary semilunar valves. Although neural crest cells have been thought to have no association with the formation of the semilunar valves, our experiment indicates that such association indeed occurs.

Animals↗
PubMed1990

Fluorometric determination of pseudocholinesterase activity in postmortem blood samples.

A fluorometric assay using 3-(p-hydroxyphenyl) propionic acid (HPPA) was conducted to determine the activity of pseudocholinesterase (ChE) [Enzyme Commission (EC) No. 3.1.1.8] in postmortem blood samples so as to test for organophosphate poisoning. By the enzymatic reaction of ChE, its substrate, benzoylcholine, produces choline, which is oxidized by choline oxidase to generate hydrogen peroxide. HPPA is oxidized by hydrogen peroxide and peroxidase to become the fluorogenic dimer whose concentration is measured fluorometrically at an excitation emission wavelength of 320 nm and an elimination emission wavelength of 404 nm. The selectivity and sensitivity of the present method were found to be superior to those of conventional pH and spectrophotometric methods.

Butyrylcholinesterase↗