Search PubMed⌕ Search

Biomedical subjects

K Tamura

Publications and source records attributed to K Tamura.

At least 1,045 records · Page 58Linked to original sources
PubMed1989

Case-control study of endemic diarrheal disease in Thai children.

In a year-long, case-control study of endemic diarrheal disease among 1230 Thai children less than five years of age, rotavirus was detected in 20%, Campylobacter in 13%, Shigella in 13%, Salmonella in 12%, and enterotoxigenic Escherichia coli (ETEC) in 9%. The differences in detection of enteric pathogens between patients and controls was significant for rotavirus (P less than .001), Shigella (P less than .001), ETEC that produced heat-labile and heat-stable toxins (LT and ST; P = .005), and ST only (P less than .001). C. jejuni was most significantly associated with diarrhea in children less than 12 months [corrected] old (P = .037) and Salmonella in children less than three months of age (P = .003). Enteropathogenic E. coli (EPEC) that adhered in a localized pattern to HeLa cells was isolated from 7% of patients and 3% of controls less than six months of age. Only 50% of these E. coli strains were of EPEC serotypes. Enteroinvasive E. coli was isolated from 7% of patients more than two years of age, and new serotypes were identified.

Age Factors↗
PubMed1989

Direct identification of disulfide bond linkages in human insulin-like growth factor I (IGF-I) by chemical synthesis.

The primary structure of human IGF-I, except for the disulfide bond system, has been reported by Rinderknecht and Humbel. IGF-I afforded the corresponding characteristic peptide fragment on V8 protease digestion, which contained Cys6, Cys47, Cys48, and Cys52. Two possible fragments, Type I with Cys6-Cys47 and Cys48-Cys52, and Type II with Cys6-Cys48 and Cys47-Cys52, were synthesized. The disulfide bond system of IGF-I was unequivocally determined to be the Type II form along with Cys18-Cys61. Interestingly, the Type I system was included in the disulfide bond isomer produced as the main by-product in the refolding step on IGF-I synthesis by the recombinant DNA method.

Cysteine↗
PubMed1989

N-isopropyl-p-[I-123]iodoamphetamine lung imaging in a patient with chronic pulmonary thromboembolism.

A patient with a brain infarct was found to have chronic pulmonary embolism associated with perfusion defects on blood flow imaging with N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP). However, gradually increasing uptake of I-123 IMP was seen in later images, in areas distal to the embolus. The increased uptake to the embolized lung seemed to be through the systemic collateral circulation.

Aged↗
PubMed1989

Electrical and synaptic properties of myenteric plexus neurones in the terminal large intestine of the guinea-pig.

1. Intracellular recording methods were used to investigate the cellular neurophysiology of ganglion cells in the myenteric plexus of the guinea-pig rectum. The rectum is a region of the gastrointestinal tract with specialized functions that include reflex relaxation of the internal and sphincter during defaecation. Electrical and synaptic properties of myenteric neurones in the rectum had not previously been studied. Therefore, the overall aim of the work was to describe electrical and synaptic behaviour and identify neurophysiological properties of rectal neurones that might be related to specialization of function in this region of the gut. 2. Thirty-four (58%) of fifty-nine impaled cells had electrophysiological properties of AH/type 2 enteric neurones. Eighteen (30%) behaved like type 3 neurones and only two (3%) behaved like S/type 1 enteric neurones. Three per cent were presumably glial cells and the remainder were unclassifiable. 3. Nicotinic cholinergic fast EPSPs were recorded in six of thirty-four (18%) of AH/type 2 neurones and in all eighteen of the type 3 cells. Slow EPSPs occurred in five of thirty-four (15%) of AH/type 2 neurones and were absent from type 3 neurones. 4. Type 3 neurones received fast synaptic inputs from axons in each of the interganglionic fibre tracts that were connected with the ganglion containing the neurone. 5. AH/type 2 neurones were apparently multipolar neurones with long processes projecting into each of the interganglionic fibre tracts connected with the ganglion. Type 3 neurones did not have processes leaving the ganglion in the fibre tracts. 6. Run-down in amplitude of the fast EPSPs in type 3 neurones occurred when they were evoked at frequencies of 5 Hz or greater. 7. Presynaptic muscarinic cholinergic receptors behaved like autoreceptors in suppressing the release of acetylcholine at nicotinic synapses on type 3 neurones. 8. Application of 5-hydroxytryptamine, acetylcholine, substance P and forskolin mimicked the characteristics of slow EPSPs in the AH/type 2 neurones. 9. The principal difference between neuronal behaviour in the rectum and small intestine, colon and stomach was in the relative proportions of AH/type 2, S/type 1 and type 3 neurones. This is discussed in terms of the functional specialization of the rectum.

Acetylcholine↗
PubMed1989

Changes of xanthine oxidase, lipid peroxide and superoxide dismutase in mouse acute pancreatitis.

The role of free radicals in the development of pancreatitis was evaluated by measuring the level of activities of xanthine oxidase (XOD), lipid peroxide (LPO) and superoxide dismutase (SOD). Acute pancreatitis was induced in female mice fed a choline-deficient meal containing 0.5% DL-ethionine (CDE meal). Acute pancreatitis was confirmed by the changes in serum amylase level and other typical features observed microscopically 24 h after the meal was taken. Activity of XOD was elevated significantly (p less than 0.05) from the baseline of 1.13 +/- 0.19 U/g tissue to 2.34 +/- 0.46, 2.59 +/- 0.33 and 3.46 +/- 0.70 U/g tissue, 8, 12 and 24 h, respectively, after the CDE meal. The LPO level was also increased from an undetectable amount to 1.10 +/- 0.47 nmol/ml (p less than 0.05), 1.03 +/- 0.18 (p less than 0.01) at 6 and 8 h, respectively, and then returned to an undetectable amount at 12 h. The peak level of LPO was shown at 24 h, 1.76 +/- 0.40 nmol/ml (p less than 0.01) and gradually decreased until 48 h, 1.17 +/- 0.37 nmol/ml (p less than 0.01) after the CDE meal. Changes of LPO took a biphasic pattern. SOD was decreased significantly from 47.1 +/- 3.4 mU/g tissue to 30.7 +/- 2.5, 24.8 +/- 1.7 and 20.6 +/- 1.1 mU/g tissue at 8 (p less than 0.01), 12 (p less than 0.01), and 24 (p less than 0.01) h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Recombinant human tumor necrosis factor alpha suppresses autoimmune diabetes in nonobese diabetic mice.

We previously reported that administration of a streptococcal preparation (OK-432) inhibited insulitis and development of autoimmune diabetes in nonobese diabetic (NOD) mice and BB rats as animals models of insulin-dependent diabetes mellitus. In this study, we screened various cytokines that could be induced by OK-432 in vivo, for their preventive effect against diabetes in NOD mice. Among recombinant mouse IFN gamma, human IL1 alpha, human IL2, mouse granulocyte-macrophage colony-stimulating factor and human TNF alpha, only human TNF alpha suppressed insulitis and significantly (P less than 0.001) inhibited development of diabetes. NOD mice were the lowest producers of the mRNA of TNF and serum TNF on stimulation with OK-432 or with IFN gamma plus LPS, compared with C57BL/6, C3H/He, and Balb/c mice. The results imply a role for low productivity of TNF in the pathogenesis of autoimmune diabetes in NOD mice.

Animals↗
PubMed1989

Isolation of galactosaminoglycan moiety (CO-N) from protein-bound polysaccharide of Cordyceps ophioglossoides and its effects against murine tumors.

A galactosaminoglycan moiety was obtained from an antitumor polysaccharide fraction (SN-C) isolated from Cordyceps ophioglossoides culture. SN-C was subjected to sonication, then a protein-bound galactosaminoglycan (CO-N) was isolated specifically by precipitation with 10% ammonium hydroxide. When given intraperitoneally to mice, CO-N inhibited the proliferation of sarcoma 180 cells inoculated into the peritoneal cavity and exhibited a marked life-prolonging effect against ascitic tumors such as Ehrlich carcinoma and IMC carcinoma. CO-N also showed an inhibitory effect against solid Ehrlich carcinoma when given intratumorally and significantly inhibited the growth of a syngeneic solid tumor (MM46 mammary carcinoma) upon intravenous administration at a low dose. CO-N showed a cytocidal effect against cultured cells of IMC and P388D1 in vitro. Flow cytometric analysis demonstrated that fluorescein isothiocyanate-CO-N binds to the surface of Ehrlich cells.

Animals↗
PubMed1989

The correlation between molecular weight and antitumor activity of galactosaminoglycan (CO-N) from Cordyceps ophioglossoides.

A galactosaminoglycan (CO-N) obtained by ultrasonication from a protein-bound polysaccharide SN-C, which was isolated from Cordyceps ophioglossoides culture, has a direct cytotoxicity against tumor cells (Ohmori et al., Chem. Pharm. Bull., 37, 1019 (1989). High performance liquid chromatographic analysis revealed that CO-N shows a broad molecular weight distribution with an average molecular weight of 33000. A potent antitumor activity of CO-N was observed in the higher-molecular-weight fraction on gel filtration, and the low-molecular-weight fraction below 6600 showed a weak activity. However, the depolymerized CO-N (ca. 5500) obtained by further ultrasonication of the original CO-N still retained the antitumor activity of CO-N against Ehrlich ascitic carcinoma or MM46 solid mammary carcinoma.

Animals↗
PubMed1989

Evaluation of mitochondrial function by measuring the heat production in state 3 and state 4 respiration.

Using a microcalorimetric method, we have measured the heat production in states 3 and 4 respiration of a mitochondrial preparation from rat heart ventricle. Adenosine triphosphate production in state 3 respiration was also determined for the same preparation after heat production was measured. In Tris-buffered solution with pyruvate and malate used as substrates, the total heat production in states 3 and 4 respiration for a 10-min reaction period were about 709 and 207 mJ/mg of mitochondrial protein, respectively. 2,4-Dinitrophenol, an uncoupler of mitochondrial oxidative phosphorylation, increased the heat production in both states 3 and 4 respiration. On the other hand, antimycin A1, an inhibitor of the electron transport system, decreased the heat production in both states. When ventricle mitochondrial dysfunction was induced by the in vivo administration of a high dose of isoproterenol, heat production was increased in state 4 respiration. These results indicate that the calorimetric method can be used to evaluate the mitochondrial function.

Animals↗
PubMed1989

Silent myocardial ischemia is not a benign sign.

1. Objectively, provoked angina is different from non-provoked angina. a) During pacing stress testing, provoked angina showed lesser increase in coronary sinus blood flow. b) During Ergotamine testing, variant angina showed a more marked decrease in flow. c) The myocardial lactate extraction ratio was lower during the pacing induced angina. 2. During the asymptomatic period, the polyparametric changes which would become manifest appeared following differing intervals. The early recognition of the myocardial ischemia was achieved by detection of the abnormality of the regional cardiac wall motion using a newly developed device, the cardiomoveogram. 3. Therefore, we can at least conclude that silent myocardial ischemia is not a good prognostic sign.

Angina Pectoris↗
PubMed1989

The mode of action of indomethacin, aspirin and melatonin on the blockage of the first ovulation in immature rat pretreated with PMSG.

The purpose of this paper was to evaluate the anti-ovulatory effects of indomethacin, aspirin and melatonin by examining the LH sensitive 13,14-dihydroprostaglandin F2 alpha forming capacity in rat ovary. When ovulation was blocked by aspirin or melatonin, the forming capacity was strongly suppressed, and these effects were reversed by hCG injection. However, the ovulation blockage by indomethacin did not accompany the inhibition of the forming capacity. These results show that aspirin and melatonin block the ovulation via the hypothalamus-pituitary level, and indomethacin acts directly on the ovary.

Animals↗
PubMed1989

Isolation, characterization, and quantitative measurement of serum alpha 1-acid glycoprotein in cattle.

Bovine alpha 1-acid glycoprotein (alpha 1AG) was purified from pooled normal bovine sera by successive ammonium sulfate precipitation, ion-exchange chromatographies and gel filtration. Bovine alpha 1AG had a molecular weight of 42,000 +/- 2,000 and a sedimentation coefficient of 3.4S. It contained 26.6% carbohydrate. Gel isoelectric focusing revealed a microheterogeneity with 7 to 8 bands in a pI range of 3.2 to 3.7. It migrated to the alpha 1-globulin region upon immunoelectrophoresis. Single radial immunodiffusion was developed for the quantitative measurement of bovine alpha 1AG in serum. The mean serum value of alpha 1AG in 152 healthy Holstein cattle (1-12 years old) was 283.2 +/- 82.3 micrograms/ml. Elevated values (cut-off value = 450 micrograms/ml) were observed in cattle with traumatic pericarditis (100%), arthritis (100%), mastitis (91%), pneumonia (70%), and mesenteric liponecrosis (43%).

Age Factors↗
PubMed1989

Evaluation of recombinant human tumor necrosis factor by scheduled intratumoral administration in mice bearing transplantable tumors.

The antitumor effect of recombinant human tumor necrosis factor (rTNF) was examined against Meth A fibrosarcoma in BALB/c mice and Sarcoma-180 in ddY mice. Significant hemorrhagic necrosis in tumor tissues occurred within 24 hr when optimal rTNF (1,000 to 5,000 units per mouse) was injected intratumorally on day 5 after intradermal inoculation of 5 x 10(5) tumor cells. Complete tumor regression resulted when two repeated courses of administration a week, each for 3 consecutive days, were given. For this marked effect to occur, however, initial tumor weight should not be greater than 1 g. When the initial tumor was greater than 1 g the surgical removal of tumor tissues was conducted and followed by rTNF administration. This caused hemorrhagic necrosis and the regression was the case with smaller tumors. When the cured mice were rechallenged with same tumors, more than 60% of mice rejected the tumors in a specific manner. In spite of such demonstration of specific immunity, well-known immunological effector mechanisms such as augmentation of natural killer cell activity, activation of antibody dependent cellular cytotoxicity or induction of interferon activity by rTNF were not detected in normal and tumor-bearing mice, suggesting that the activation of immunoregulatory cells by TNF itself may not involve at least in an early stage of TNF treatment. These results suggest that rTNF is a potent therapeutic agent for a certain solid tumor when the protocol of administration is optimized.

Animals↗
PubMed1989

Bilateral vertebral arteriovenous fistulas and atlantoaxial dislocation associated with neurofibromatosis--case report.

The authors report a rare case involving neurofibromatosis associated with bilateral vertebral arteriovenous fistulas and atlantoaxial dislocation. Multiple neurofibromas in the craniocervical junction appeared to be the cause of the atlantoaxial dislocation in this patient, and the dislocation might have contributed to the formation of the bilateral vertebral arteriovenous fistulas. The fistulas were successfully treated by a combination of balloon embolization and surgery followed by occipitocervical fusion.

Arteriovenous Fistula↗
PubMed1989

Intranuclear androgen-receptor complex binding sites of mouse submandibular gland.

Nuclear androgen-receptor binding sites in chromatin regions of mouse submandibular gland were studied. Cytosol androgen receptors prelabeled with [3H]androgen interacted with the crude nuclei in mouse submandibular gland and activation of the receptor was a prerequisite for this interaction. After in vivo administration of [3H]androgen to female mice, radioactivities were found in the nuclei purified from submandibular gland tissues and the [3H]androgen-labeled purified nuclei were further digested with micrococcal nuclease. The androgen receptor was found in solubilized, active chromatin fractions which contained mono- and dinucleosomes. By an in vitro exchange assay, endogenous androgen-receptor complexes associated with chromatin binding sites in intact males were found in the solubilized fraction after micrococcal nuclear digestion, whereas such complexes were not found in females. These results suggest that the androgen receptors translocated to the nuclei and became associated with chromatin and that this association occurred in transcriptionally active chromatin regions that were preferentially sensitive to micrococcal nuclease.

Animals↗
PubMed1989

[Performance evaluation of X-ray computed tomography "TCT-700 S". 2].

UNLABELLED: The performance of the rotate/rotate CT scanner TCT-700 S (Toshiba) was evaluated on the basis of the item entitled "User's initial acceptance tests (phase II)" set forth in "Standard of performance evaluation for x-ray computed tomography (second recommendation)" proposed by Takenaka et al. (1982). This second report in the series describes measurements of exposure and the relation between exposure and such other performance aspects as noise and contrast resolution. The exposure-performance recommendation proposes measurements of average exposure in the scanning field and a radial exposure profile. RESULTS: 1. In the case of multiple scanning, average exposures in the field were uniform because all surfaces of the perpendicular object were oriented toward the incidence of the x-ray beam. At a minimum scanning speed of 1.8 second, however, a discrepancy of 3 times occurred in exposures observed reciprocally from the left and right sides of the object. This phenomenon indicates that only one-half of the object surface is oriented toward the x-ray beam and that the x-ray tube and detectors rotate in mutually opposite directions. In the case of multiple scannings, when slice thicknesses were 10 mm, 5 mm and 2 mm, average exposures were almost uniform. But with a slice thickness of 1 mm, average exposure was twice as great. This measurement indicates inadequate collimation in the case of a 1 mm slice thickness. These average exposures were roughly proportional to the mAs (product of tube current and scan speed) in the range between a minimum of 100 mAs and a maximum of 1200 mAs. 2. Noise increased in proportion to decrease of average exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation Dosage↗
PubMed1989

[Effects of anticonvulsants on cellular immunity].

The effects of anticonvulsants on cellular immunity were examined in murine models. Fresh splenocytes were obtained from mice which had been intraperitoneally given 1 mg of phenytoin, 2 mg of phenobarbital, or 20mg of valproate for 28 days. The serum concentration of phenytoin, phenobarbital and valproate in these animals were 10-20 micrograms/ml, 30-40 micrograms/ml and 50-70 micrograms/ml, respectively. The proliferative response of splenocytes to mitogens was assessed by 3H-thymidine incorporation. The cytotoxic activities of cells such as natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and lymphokine-activated killer (LAK) cells were estimated by a 4 hr-51Cr release assay. Phenytoin suppressed lymphocyte proliferation, NK activity, and CTL activity, but never LAK activity. Phenobarbital suppressed proliferative response to rIL-2 and CTL activity, but did not suppress NK activity nor LAK activity. In turn sodium pyruvate never suppressed any activity on cellular immunity.

Animals↗