Optimizing cooling rates for cryopreservation of isolated pancreatic islets.
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Animals↗
Biomedical subjects
T Tsuchiya
Publications and source records attributed to T Tsuchiya.
[Clinicobacteriological study of Pasteurella multocida infection as a zoonosis. (2)--Comparisons of P. multocida separated from patients and their pet dogs and cats].
A total of 17 strains of Pasteurella multocida, of which 13 were isolated from patients treated at Nihon University Itabashi Hospital or Nihon University Surugadai Hospital between April, 1984 and March, 1991 and 4 from 1 dog and 3 cats kept by the patients, were evaluated with respect to their biochemical properties, sensitivity to drugs, and serotype. The isolated strains were all considered to be Pasteurella multocida subsp. multocida because of the agreement of their responses to indole, sorbitol and dulcitol with those of this subspecies, except for 1 sorbitol-negative strain of Pasteurella multocida subsp. septica isolated from 1 patient who had been bitten by a cat. All the isolated strains showed high sensitivities to various drugs. The serotype was capsular type A, which is often observed in cats and dogs, in 7 strains, which consisted of 6 of the 7 strains derived from the airway of the patients and 1 of the 6 strains derived from bit or scratch wound. The remaining strains could not be classified. Five morphological types, namely 1, 3, 3.8, 6, and 8 were observed. In 2 patients, Pasteurella multocida subsp. multocida of the same serotype was also isolated from their cats. One of these patients had intimate contact with the cat including kissing. Our findings suggest that: 1) Pasteurella multocida subsp. multocida has been responsible for most conventional cases of Pasteurella multocida infection. 2) Strains isolated from patients differ in the capsular type according to the disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Myosin phosphorylation-independent contraction induced by phorbol ester in vascular smooth muscle.
In isolated rat aorta, carotid artery, tail artery, rabbit aorta and mesenteric artery, but not in ear artery, 1 microM 12-deoxyphorbol 13-isobutyrate (DPB) induced a sustained contraction. However, DPB increased cytosolic Ca++ concentration ([Ca++]i) only in rat aorta and carotid artery. Similar results were obtained with phorbol 12,13-dibutyrate, although the inactive phorbol ester, 4-alpha-phorbol 12,13-dibutyrate, was ineffective. In rat aorta, DPB-induced contraction was followed by an increase in 20 kDa myosin light chain (MLC) phosphorylation. Both contraction and MLC phosphorylation stimulated by DPB were greater than those due to high K+ for a given increase in [Ca++]i. A Ca++ channel blocker, verapamil, decreased the DPB-induced increments in [Ca++]i and MLC phosphorylation to their respective resting levels, although contraction was inhibited only slightly. In the absence of external Ca++ (with 0.5 mM ethyleneglycol bis(beta-aminoethyl-ether)tetraacetic acid), DPB induced sustained contraction without increasing [Ca++]i or MLC phosphorylation. This contraction was followed by an increase in stiffness and force recovery after a shortening step. These results suggest that the contraction induced by DPB in rat aorta is due to increase in [Ca++]i followed by MLC phosphorylation and Ca++ sensitization of MLC phosphorylation. In the presence of verapamil or in the absence of external Ca++, DPB may increase cross-bridge cycling by activating an unknown mechanism that is not dependent on an increase in MLC phosphorylation.
Animals↗
Receptor agonists induce myosin phosphorylation-dependent and phosphorylation-independent contractions in vascular smooth muscle.
In isolated rat aorta, 72.7 mM KCI, 10 microM prostaglandin F2 alpha, 30 nM endothelin-1 and 1 microM norepinephrine increased muscle tension, cytosolic Ca++ concentration ([Ca++]i) and 20 kDa myosin light chain (MLC) phosphorylation. The levels of contractile tension and MLC phosphorylation at a given [Ca++]i were greatest in the presence of endothelin-1 followed by prostaglandin F2 alpha greater than norepinephrine greater than high K+. Verapamil inhibited the high K(+)-induced increments to their respective resting levels. Verapamil also almost completely inhibited the receptor agonist-induced increments in [Ca++]i and MLC phosphorylation, although a part of the contraction was not inhibited. Ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid further decreased [Ca++]i and muscle tension, suggesting that a part of the contraction is regulated by [Ca++]i below a resting level. Receptor agonists induced sustained contraction in the absence of external Ca++ which was not followed by the increase in [Ca++]i or MLC phosphorylation. This contraction was followed by the increments in shortening velocity and stiffness. In the rabbit mesenteric artery permeabilized with Staphylococcus aureus, alpha-toxin, norepinephrine and endothelin-1 shifted the Ca(++)-tension curve to the left in the presence of GTP. From these results, it is suggested that high K(+)-induced sustained contraction of vascular smooth muscle is attributable to an increase in [Ca++]i followed by an increase in MLC phosphorylation. In addition to this fundamental mechanism, receptor agonists increase Ca+ sensitivity of MLC phosphorylation when [Ca++]i is higher than resting level resulting in a greater contraction than that induced by high K+ for a given increase in [Ca++]i.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
A novel mechanism of cation/substrate cotransport: Na+/H+/adenosine cotransport in Vibrio parahaemolyticus.
Adenosine is actively transported with Na+ in Vibrio parahaemolyticus (Sakai, Y., Tsuda, M., Tsuchiya, T. (1987) Biochim, Biophys. Acta 893, 43-48). The proton conductor carbonylcyanide m-chlorophenylhydrazone, CCCP, strongly inhibited active transport of adenosine at pH 8.5 as well as at pH 7.0. This seemed peculiar because the driving force, an electrochemical potential of Na+, is established by the Na(+)-extruding respiratory chain at pH 8.5 in this organism, although it is established by the function of the Na+/H+ antiporter at pH 7.0. This suggested that H+ might be involved in the adenosine transport. We detected H+ uptake induced by adenosine influx in V. parahaemolyticus cells in the presence of Na+, but not in its absence, suggesting the occurrence of Na+/H+/adenosine cotransport. We isolated formycin A-resistant mutants which showed defective adenosine transport. The mutation resulted in simultaneous losses of Na+ uptake and H+ uptake induced by adenosine. In revertants from these mutants the Na+ uptake and H+ uptake were restored simultaneously. The frequencies of reversion were in the order of 10(-7), indicating that the mutations were single mutations; namely that Na+/adenosine cotransport and H+/adenosine cotransport took place via the same carrier. Thus, we conclude that adenosine is transported by the novel mechanism of Na+/H+/adenosine cotransport in V. parahaemolyticus.
Adenosine↗
Na(+)-coupled ATP synthesis in a mutant of Vibrio parahaemolyticus lacking H(+)-translocating ATPase activity.
An H(+)-translocating ATPase-defective mutant of Vibrio parahaemolyticus YS-1 grew well on lactate as a sole source of carbon at pH 8.5 under aerobic conditions, but not under anaerobic conditions. Both wild type cells and the mutant cells could grow on lactate at pH 8.5 even in the presence of an H+ conductor, carbonylcyanide m-chlorophenylhydrazone (CCCP), but not at pH 7.5. Oxidative phosphorylation resistant to CCCP in the mutant occurred at pH 8.5. These findings suggest the existence of Na(+)-coupled oxidative phosphorylation which is functional at alkaline pHs in V. parahaemolyticus. In fact, we observed ATP synthesis driven by an artificially imposed Na+ gradient in YS-1 cells, which was resistant to CCCP.
Adenosine Triphosphate↗
Developmentally and regionally regulated alterations of octamer- and GC-box-binding activities during the postnatal development of mouse cerebellum.
Gel-mobility analyses using a DNA probe containing the SV40 enhancer-promoter revealed that the DNA-binding activities of cerebellar extracts changed drastically during the postnatal development of mouse brain. Three major DNA-protein complexes formed on the 72-bp enhancer (complexes E-I, E-II and E-III) were detected in the extracts prepared from the 2- and 10-day-old mouse cerebellum, but two of them (complexes E-II and E-III) were not detected in 3- and 7-week-old mice. In contrast, the formation of the complexes E-II and E-III, but not E-I, was observed in the cerebral cortex extracts throughout postnatal development until at least 7 weeks after birth. The addition of the octamer motif as a competitor abolished the formation of these three complexes. On the other hand, the formation of DNA-protein complexes on the 21-bp promoter by the cerebellar extracts increased after birth, while this increase in the formation of the complexes was not detected in the cerebral cortex extracts. This complex formation was found to be dependent upon the GC-box and to be stimulated by the addition of Zn2+, indicating that the protein binding to the 21-bp promoter may contain intramolecular zinc fingers. Thus, the expression of the octamer- and the GC-box-binding proteins are developmentally and regionally controlled in the cerebellum during the postnatal development of the mouse brain.
Animals↗
Two- and three-dimensional behavior of Rayleigh-Taylor and Kelvin-Helmholtz instabilities.
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Journal Article↗
[A case of anaphylactic shock with coronary vasospasm].
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Anaphylaxis↗
Chaos-theoretical analysis of possible structural quantities for globular proteins.
Chaos-theoretical analysis is made on possible candidates for the structural quantities. Since this is a first attempt to incorporate chaos into protein structural studies, a brief introduction to chaos especially the correlation integral method is given. It is shown that for several globular proteins the quantities called N14 and the distance rho of each C alpha atom from the center of mass suggest their deterministic origin which, we consider, is an essential requirement for a parameter to be recognized as the structural quantity. The claim made by the originator of N14 that the quantities N14 and rho can be good candidates for structural quantities is supported here by a completely new and different analysis.
Alcohol Dehydrogenase↗
Species differences between rats and mice in the teratogenic action of ethylenethiourea: in vivo/in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system.
In vivo/in vitro studies on rats showed that ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that ethylenethiourea is teratogenic in rats but not in mice.
Animals↗
Alzheimer's disease amyloid beta-clipping enzyme (APP secretase): identification, purification, and characterization of the enzyme.
Alzheimer's disease (AD) is the most frequent cause of dementia, although no genetic abnormality has been identified. Recent studies have elucidated the molecular defect in AD, including the abnormal deposition of amyloid beta peptide (beta/A4) in senile plaques of affected individuals. Normal brain contains the enzyme, APP secretase, which cleaves inside the beta/A4 portion of the precursor protein (APP); abnormal processing of APP occurs in AD brain. Until now, no evidence has been provided that APP secretase is an intracellular proteinase. We have now prepared two synthetic substrates of APP secretase, both of which contain the cleavage point and are much more sensitive than substrates previously available to identify APP secretase. Using these substrates, we found an intracellular proteinase that has APP secretase activity. This proteinase has been identified as cathepsin B.
Alzheimer Disease↗
Synthesis of 3'-deoxy-3'-fluorokanamycin A and 3',4'-dideoxy-3'-fluorokanamycin A.
3'-Deoxy-3'-fluorokanamycin A (14) has been prepared by condensation of 6-azido-2,4-di-O-benzyl-3,6-dideoxy-3-fluoro-alpha-D-glucopyranlsyl++ + bromide (8) and 6-O-(2-O-acetyl-4,6-O-cyclohexylidene-3-deoxy- 3-tosylamino-alpha-D-glucopyranosyl)-2-deoxy-1,3-di-N-tosylstre ptamine (10). Compound 8 was obtained from 3-deoxy-3-fluoro-1,2:5,6-di-O-isopropylidene-D-glucofuranose in seven steps. 3',4'-Dideoxy-3'-fluorokanamycin A (22) has been prepared from 12 through selective 4'-chlorodeoxygenation, a key reaction. Both 14 and 22 were more active than 3'-deoxykanamycin A against both sensitive and resistant bacteria.
Anti-Bacterial Agents↗
Response of adrenal sympathetic efferent nerve activity to mechanical and thermal stimulations of the facial skin area in anesthetized rats.
The effect of mechanical and thermal stimulations to the forehead or cheek innervated by the trigeminal nerve on adrenal sympathetic efferent nerve activity was studied in alpha-chloralose-urethane anesthetized rats. Innoxious mechanical stimulations to the forehead or cheek caused a reflex decrease of nerve activity, while noxious mechanical stimulations to the forehead or cheek caused a reflex increase in activity. Thermal stimulation of the forehead and bilateral cheeks at below 15 degrees C or above 45 degrees C increased activity though it failed to do so between 20 and 40 degrees C. These excitatory responses lasted only as long as the period of the stimulation. These results suggest that excitatory reflex responses mediated by supraspinal circuit to adrenal nerve activity are not, characteristically, of an enduring nature.
Adrenal Glands↗
Evaluation of biocompatibility, based on quantitative determination of the vascular response induced by material implantation.
The biocompatibility of nine different materials, including positive and negative references, 4 polyurethane based and 3 latex based materials was investigated by (1) cytotoxic assay using V79 chinese hamster cells, (2) the thickness of inflammatory layer at 3 and 7 days after intramuscular implantation test, and (3) the course of the blood flow in tissue reaction around subcutaneously implanted materials using Laser Doppler Flowmetry (LDF) over 14 days following implantation. In addition, for some materials, different modes of sterilization were compared. Although the three methods explore different reactive systems, the material ranking obtained was highly similar for the three methods, suggesting a relative accuracy between them. For one latex however, an absence of cytotoxic effect in culture and a highly intense response by LDF investigation of the same order of magnitude as for the positive reference implant suggest that bioincompatibility may result from the material itself and cannot be exclusively investigated by the leaching of toxic components.
Anesthesia↗
A new monoclonal antibody, PM-2K, specifically recognizes tissue macrophages but not blood monocytes.
A new monoclonal antibody, PM-2K, was raised against 24-h cultured human peritoneal macrophages. Immunohistochemically, PM-2K recognized most tissue macrophages in lymphoreticular organs such as the thymus, spleen, lymph node, and tonsil. Kupffer cells of the liver, alveolar macrophages, and macrophages in the interstitial tissue of the kidney, pancreas, and many other organs were also positively labelled. On the other hand, PM-2K failed to recognize blood monocytes, freshly isolated peritoneal macrophages, microglial cells, osteoclasts, and dendritic cells such as Langerhans cells, interdigitating cells, and follicular dendritic cells. In various pathological conditions, PM-2K labelled a wide variety of proliferating macrophages. Reaction products of PM-2K were observed by immunoelectron microscopy on the cytoplasmic membrane of cultured peritoneal macrophages. The molecular weight of the antigen recognized by PM-2K was determined to be 150 kD by Western blotting. As no cells other than macrophages were reactive with PM-2K, this antibody is considered to be very useful not only in the investigation of macrophage differentiation and maturation, but also in the diagnosis of various proliferative disorders of macrophages.
Animals↗
Comparative studies of embryotoxic action of ethylenethiourea in rat whole embryo and embryonic cell culture.
The effects of ethylenethiourea (ETU) were investigated using rat (Wistar-imamichi) embryos cultured from days 11 to 13 of gestation or cultured rat embryonic cells extracted on day 11. Malformations in cultured embryos at the concentration of 30 micrograms/ml of ETU were found in the head and tail, which were severely affected, as well as the limb and face. All embryos exposed to 150 and 300 micrograms/ml of ETU had malformed heads, tails, limbs, and facial configurations. Protein contents of the cultured embryos were decreased dose-dependently at the concentrations ranging from 30 to 300 micrograms/ml. In the histological studies of the cultured embryos with ETU, thinner neuroepithelium in head was observed. In the embryonic cells extracted on day 11 of gestation, ETU dose-dependently inhibited the differentiation of midbrain (MB) cells into neurons and that of limb bud (LB) cells into chondrocytes at the concentrations ranging from 30 to 600 micrograms/ml of ETU. The concentrations of ETU that inhibited the production of differentiated foci by 50% (IC50) were 170 micrograms/ml in LB cells of day 11, and greater than 600 micrograms/ml in LB cells on day 12 of development. Therefore, differentiation of MB cells was more sensitive to ETU than the differentiation of LB cells. These results indicated that there was a reasonable correlation of ETU induced changes in cultured whole embryos and embryonic cells.
Abnormalities, Multiple↗
Effects of pulsing electromagnetic fields on cultured cartilage cells.
In order to evaluate the effects of pulsing electromagnetic fields (PEMFs) on cell proliferation and glycosaminoglycan (GAG) synthesis and to study the action site of PEMF stimulation in the cells, we performed a series of experiments on rabbit costal growth cartilage cells and human articular cartilage cells in culture. A PEMF stimulator was made using a Helmholz coil. Repetitive pulse burst electric currents with a burst width of 76 ms, a pulse width of 230 microseconds and 6.4 Hz were passed through this coil. The magnetic field strength reached 0.4 mT (tesla) on the average. The syntheses of DNA and GAG were measured by 3H-thymidine and 35S-sulfuric acid incorporations. The effects on the cells treated with lidocaine, adriamycin and irradiation were also measured using a colony forming assay. The PEMF stimulation for the duration of 5 days promoted both cell proliferation and GAG synthesis in growth cartilage cells and intermittent stimulation on and off alternatively every 12 h increased them most significantly, while, in articular cartilage cells, the stimulation promoted cell proliferation, but did not enhance GAG synthesis. PEMF stimulation promoted cells treated with lidocaine more significantly than with other agents. These results present evidence that intermittent PEMF stimulation is more effective on both cell proliferation and GAG synthesis of cartilage cells than continuous stimulation, and that the stimulation could exert effects not by nucleus directly, but by the cellular membrane-dependent mechanism. This study provides further basic data to encourage the clinical application of PEMF stimulation on bone and cartilage disorders.
Animals↗