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Biomedical subjects

A Tani

Publications and source records attributed to A Tani.

At least 19 recordsLinked to original sources
PubMed2005

A novel nicotinoprotein aldehyde dehydrogenase involved in polyethylene glycol degradation.

A gene (pegC) encoding aldehyde dehydrogenase (ALDH) was located 3.4 kb upstream of a gene encoding polyethylene glycol (PEG) dehydrogenase (pegA) in Sphingomonas macrogoltabidus strain 103. ALDH was expressed in Escherichia coli and purified on a Ni-nitrilotriacetic acid agarose column. The recombinant enzyme was a homotetramer consisting of four 46.1-kDa subunits. The alignment of the putative amino acid sequence of the cloned enzyme showed high similarity with a group of NAD(P)-dependent ALDHs (identity 36-52%); NAD-binding domains (Rossmann fold and four glycine residues) and catalytic residues (Glu225 and Cys259) were well conserved. The cofactor, which was extracted from the purified enzyme, was tightly bound to the enzyme and identified as NADP. The enzyme contained 0.94 mol NADP per subunit. The enzyme was activated by Ca(2+), but by no other metals; no metal (Zn, Fe, Mg, or Mn) was detected in the purified recombinant enzyme. Activity was inhibited by p-chloromercuric benzoate, and heavy metals such as Hg, Cu, Pb and Cd, indicating that a cysteine residue is involved in the activity. Enzyme activity was independent of N,N-dimethyl-p-nitrosoaniline as an electron acceptor. Trans-4-(N,N-dimethylamino)-cinnamaldehyde was not oxidized as a substrate, but the compound worked as an inhibitor for the enzyme, as did pyrazole. The enzyme acted on n-aldehydes C(2)-C(14)) and PEG-aldehydes. Thus the enzyme was concluded to be a novel Ca(2+)-activating nicotinoprotein (NADP-containing) PEG-aldehyde dehydrogenase involved in the degradation of PEG in S. macrogoltabidus strain 103.

Alcohol Dehydrogenase↗
PubMed2005

Damage of cutaneous peripheral nervous system evolves differently according to the disease phase and subset of systemic sclerosis.

OBJECTIVE: Evidence shows that peripheral nervous system (PNS) is involved in systemic sclerosis (SSc), but few morphological studies have assessed the ultrastructural pathological modifications. The aim was to study ultrastructural modifications of skin PNS fibres in SSc according to subsets [limited SSc (lSSc) and diffuse SSc (dSSc)] and phases (early and advanced) of the disease. METHODS: Skin biopsies were taken from the forearms of 23 SSc patients (11 lSSc and 12 dSSc) and 10 controls. Each biopsy was processed for transmission electron microscopy (TEM). RESULTS: At TEM, observation in skin from early lSSc, signs of inflammation were evident, while PNS fibres were not damaged. The microvascular wall showed hypertrophic endothelial cells bulging into the lumen. In advanced lSSc, fibrosis prevailed on inflammation and slight ultrastructural alterations of PNS fibres were evident in the papillary derma. In early dSSc, ultrastructural alterations of PNS fibres, similar to those observed in the advanced phase of lSSc, were found together with signs of inflammation and fibrosis. In advanced dSSc, in the papillary and reticular dermis PNS fibres were reduced and showed relevant ultrastructural alterations. CONCLUSIONS: In SSc, PNS ultrastructure damage is linked to the progression and severity of skin involvement. The alterations evolve from the early to the advanced phase mainly in the diffuse subset. In particular, the severe PNS lesions found in advanced lSSc are already present and widely diffuse in early dSSc and the microvascular involvement in early lSSc seems to precede the modification of the PNS in the skin. Thus, an early therapeutic approach can be useful to reduce the progression of PNS and skin damage in SSc patients.

Adult↗
PubMed2004

Modeling benzene with single-site potentials from ab initio calculations: a step toward hybrid models of complex molecules.

Extensive ab initio calculations at the MP2/6-31G* level have been carried out to sample the energy surface for the interactions of the benzene dimers. This database has been used to parameterize two anisotropic single-site models, meant to be used as building blocks in hybrid models of complex, liquid crystal forming molecules. A quadrupolar Gay-Berne (GBQIII) and an S-function (SF) Corner potentials have been obtained in this way. Their ability to reproduce, qualitatively at least, the phase diagram as well as energetic and structural properties of benzene has been tested with Monte Carlo simulations and compared with previous literature potentials, GBQI [S. Gupta et al., Mol. Phys. 65, 961 (1988)] and GBQII [T. R. Walsh, Mol. Phys. 100, 2867 (2002)]. It turned out that GBQI showed no melting transition in the temperature range explored (100-400 K), while GBQII underwent a phase transition from solid to gas, with no liquid phase. Conversely, both models parameterized on our database of ab initio interaction energies (GBQIII and SF) gave rise to a stable liquid phase. Melting has been observed between 100 and 150 K (GBQIII) and in the range 300-350 K (SF), i.e., substantially below and slightly above the experimental value at ambient pressure, 278 K. The description of the crystal structure of benzene at atmospheric pressure is also in better agreement with experimental data if the SF model is used, while positional correlations in the liquid are better described by the GBQIII potential. The S-function potential is also computationally more convenient. These results could be useful in the semirealistic modeling of more complex molecules.

Journal Article↗
PubMed2004

Treatment of the yeast Rhodotorula glutinis with AlCl(3) leads to adaptive acquirement of heritable aluminum resistance.

When aluminum (Al) was added to a culture, growth of Rhodotorula glutinis IFO1125 was temporarily arrested, showing longer lag phases, depending on the Al concentrations (50-300 microM) added, but the growth rates were not affected at all. Resistant strains obtained by one round of plate treatment containing Al reverted the resistance level to the wild-type level when cultivated without Al. Repeated Al treatments, however, induced heritable and stable Al resistance, the level of which was increased up to 4,000 microM by stepwise increments in Al concentrations. Thus, the heritable Al resistance adaptively acquired was due neither to adaptation nor to mutation, but to a mechanism which has yet to be studied. Heritable Al resistance seemed to release the Al inhibition of magnesium uptake.

Adaptation, Physiological↗
PubMed2004

Sphingosine 1-phosphate induces cell contraction via calcium-independent/Rho-dependent pathways in undifferentiated skeletal muscle cells.

We have previously shown that sphingosine 1-phosphate (S1P) can induce intracellular Ca(2+) mobilization and cell contraction in C2C12 myoblasts and that the two phenomena are temporally unrelated. Although Ca(2+)-independent mechanisms of cell contraction have been the focus of numerous studies on Ca(2+) sensitization of smooth muscle, comparatively less studies have focused on the role that these mechanisms play in the regulation of skeletal muscle contractility. Phosphorylation and activation of myosin by Rho-dependent kinase mediate most of Ca(2+)-independent contractile responses. In the present study, we examined the potential role of Rho/Rho-kinase cascade activation in S1P-induced C2C12 cell contraction. First, we showed that depletion of Ca(2+), by pre-treatment with BAPTA, did not affect S1P-induced myoblastic contractility, whereas it abolished S1P-induced Ca(2+) transients. These results correlated with the absence of troponin C and with the immature cytoskeletal organization of these cells. Experimental evidence demonstrating the involvement of Rho pathway in S1P-stimulated myoblast contraction included: the activation/translocation of RhoA to the membrane in response to agonist-stimulation in cells depleted of Ca(2+) and the inhibition of dynamic changes of the actin cytoskeleton in cells where Rho functions had been inhibited either by overexpression of RhoGDI, a physiological inhibitor of GDP dissociation from Rho proteins, or by pretreatment with Y-27632, a specific Rho kinase inhibitor. Contribution of protein kinase C in this cytoskeletal rearrangement was also evaluated. However, the pretreatment with Gö6976 or rottlerin, specific inhibitors of PKC alpha and PKC delta, respectively, failed to inhibit the agonist-induced myoblastic contraction. Single particle tracking of G-actin fluorescent probe was performed to statistically evaluate actin cytoskeletal dynamics in response to S1P. Stimulation with S1P was also able to increase the phosphorylation level of myosin light chain II. In conclusion, our results strongly suggest that Ca(2+)-independent/Rho-Rho kinase-dependent pathways may exert an important role in S1P-induced myoblastic cell contraction.

Actins↗
PubMed2004

Effects of S1P on myoblastic cell contraction: possible involvement of Ca-independent mechanisms.

Sphingosine-1-phosphate (S1P) is a lipid mediator, which affects many essential processes such as cell proliferation, differentiation and contraction in many cell types. We have previously demonstrated that the lipid mediator elicits Ca(2+) transients in a myoblastic cell line (C2C12) by interacting with its specific receptors (S1PR(s)). In the present study, we wanted to correlate the Ca(2+) response with activation of myoblastic cell contractility. C2C12 cells were first investigated for the expression and cellular organization of cytoskeletal proteins by immunoconfocal microscopy. We found that myoblasts exhibited a quite immature cytoskeleton, with filamentous actin dispersed as a web-like structure within the cytoplasm. To evaluate intracellular Ca(2+) mobilization, the cells were loaded with a fluorescent Ca(2+) indicator (Fluo-3), stimulated with S1P and simultaneously observed with differential interference contrast and fluorescence optics. Exogenous S1P-induced myoblastic cell contraction was temporally unrelated to S1P-induced intracellular Ca(2+) increase; cell contraction occurred within 5-8 s from stimulation, whereas intracellular Ca(2+) increase was evident only after 15-25 s. To support the Ca(2+) independence of myoblastic cell contraction, the cells were pretreated with a Ca(2+) chelator, BAPTA/AM, prior to stimulation with S1P. In these experimental conditions, the myoblasts were still able to contract, whereas the S1P-induced Ca(2+) transients were completely abolished. On the contrary, when C2C12 cells were induced to differentiate into skeletal myotubes, they responded to S1P with a rapid cell contraction concurrent with an increase in the intracellular Ca(2+). These data suggest that Ca(2+)-independent mechanism of cell contraction may be replaced by Ca(2+)-dependent ones during skeletal muscle differentiation.

Actins↗
PubMed2003

The application of proton transfer reaction-mass spectrometry (PTR-MS) to the monitoring and analysis of volatile organic compounds in the atmosphere.

Proton transfer reaction-mass spectrometry (PTR-MS) is a new and emerging technique for the measurement and monitoring of volatile organic compounds (VOCs) at low concentrations in gaseous samples in more-or-less real time. Utilising chemical ionisation, it combines the desirable attributes of high sensitivity and short integration times with good precision and accuracy. Recently it has been exploited in applications related to atmospheric science. Here, the principles of operation of the PTR-MS are described, its advantages and disadvantages discussed, its inherent uncertainties highlighted, some of its uses in atmospheric sciences reviewed, and some suggestions made on its future application to atmospheric chemistry.

Air Pollutants↗
PubMed2003

The effect of gravity on surface temperatures of plant leaves.

A fundamental study was conducted to develop a facility having an adequate air circulation system for growing healthy plants over a long-term under microgravity conditions in space. To clarify the effects of gravity on heat exchange between plant leaves and the ambient air, surface temperatures of sweet potato and barley leaves and replica leaves made of wet paper and copper were evaluated at gravity levels of 0.01, 1.0, 1.5 and 2.0 g for 20 s each during parabolic aeroplane flights. Thermal images were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 18% and an irradiance of 260 W m-2. Mean leaf temperatures increased by 0.9-1.0 degrees C with decreasing gravity levels from 1.0 to 0.01 g and decreased by 0.5 degrees C with increasing gravity levels from 1.0 to 2.0 g. The increase in leaf temperatures was at most 1.9 degrees C for sweet potato leaves over 20 s as gravity decreased from 1.0 to 0.01 g. The boundary layer conductance to sensible heat exchange decreased by 5% when the gravity decreased from 1.0 to 0.01 g at the air velocity of 0.2 m s-1. The decrease in the boundary layer conductance with decrease in the gravity levels was more significant in a lower air velocity. Heat exchange between leaves and the ambient air was more retarded at lower gravity levels because of less sensible and latent heat transfers with less heat convection.

Air Conditioning↗
PubMed2003

Altered Cx43 expression during myocardial adaptation to acute and chronic volume overloading.

Gap-junctions are specialized regions of intercellular contacts allowing electrical impulse propagation among adjacent cardiomyocytes. Connexin43 (Cx43) is the predominant gap-junction protein in the working ventricular myocardium and its reduced expression has been extensively implicated in the genesis of conduction abnormalities and re-entry arrhythmia of chronically hypertrophied hearts. In contrast, data on the role played by this protein during cardiac remodeling and early phases of developing hypertrophy are lacking. Therefore, in the present study, we investigated this issue using an experimental model of pig left ventricle (LV) volume overloading consisting in the creation of an aorto-cava fistula. At scheduled times (6, 24, 48, 96, 168 h, and 2, 3 months after surgery) echocardiographic and haemodynamic measurements were performed and myocardial biopsies were taken for the morphological and biochemical analyses. When faced with the increased load, pig myocardium underwent an initial period (from 6 up to 48 h) of remarkable tissue remodeling consisting in the occurrence of cardiomyocyte damage and apoptosis. After that time, the tissue developed a hypertrophic response that was associated with early dynamic changes (up-regulation) in Cx43 protein expression, as demonstrated by Western blot and confocal immunofluorescence analyses. However, an initial transient increase of this protein was also found after 6 h from surgery. With the progression of LV hypertrophy (from 168 hr up to 3 months), a reduction in the myocardial Cx43 expression was, instead, observed. The increased expression of Cx43 protein during acute hypertrophic response was associated with a corresponding increase in the levels of its specific mRNA, as detected by RT-PCR. We concluded that up-regulation of Cx43 gap-junction protein could represent an immediate compensatory response to support the new working conditions in the early stages of ventricular overloading.

Adaptation, Physiological↗
PubMed2001

Expression of functional lung resistance--related protein predicts poor outcome in adult T-cell leukemia.

Chemotherapy of patients with adult T-cell leukemia (ATL) has been unsuccessful. The poor outcome is thought to be caused mainly by the drug resistance of ATL cells. Lung resistance-related protein (LRP) is a novel protein associated with drug resistance. The expression of LRP messenger RNA (mRNA) was evaluated by slot blot analysis in 55 patients with ATL. Of these patients, 36 had acute, 12 chronic, and 7 lymphoma-type ATL. The expression levels of LRP mRNA were significantly higher in chronic ATL than in lymphoma-type ATL (P =.007). The expression of LRP mRNA was higher in patients with white blood cell counts above 30,000/microL (P =.038) or with abnormal lymphocyte counts above 10,000/microL (P =.007) than in the remaining patients. The enhanced efflux of [(14)C]doxorubicin from nuclei isolated from ATL cells that expressed high levels of LRP was inhibited by a polyclonal antibody against LRP, and the accumulation of doxorubicin in the isolated nuclei was increased by the anti-LRP antibody. In acute and lymphoma-type ATL patients, high expression of LRP mRNA at diagnosis correlated with shorter survival, and a Cox proportional hazards model showed that LRP expression is an independent prognostic factor. These findings suggest that functionally active LRP is expressed in some ATL cells and that it is involved in drug resistance and poor prognosis in ATL. (Blood. 2001;98:1160-1165)

Active Transport, Cell Nucleus↗
PubMed2001

Decreased perfusion of the bilateral thalami in patients with chronic pain detected by Tc-99m-ECD SPECT with statistical parametric mapping.

The purpose of this study was to examine whether the Tc-99m-ECD SPECT can detect any difference between the brain perfusion in patients with chronic pain and normal controls by means of the Statistical Parametric Mapping (SPM96). The subjects were twelve patients with chronic pain (CP group) and twelve normal controls (NC group). After informed consent was obtained, 720 MBq of Tc-99m-ECD was intravenously injected as a bolus. The SPECT data were acquired once for 20 mins from 5 mins after i.v. injection of Tc-99m-ECD, with a triple-head rotating gamma camera. The SPECT data were transformed into a standard stereotactic space, and group comparisons between CP and NC groups were performed on a voxel-by-voxel basis. The subset of voxels exceeding a threshold of p < 0.001 in omnibus comparisons and remaining significant after correction for multiple comparison (p < 0.05) was displayed as a volume image rendered in three orthogonal projections. There was a significant decrease in perfusion in the bilateral thalami in the CP group, suggesting that perfusion in the thalamus generally decreases in patients with chronic pain. Tc-99m-ECD SPECT with SPM96 may be useful for studies of the mechanisms of chronic pain.

Adult↗
PubMed2001

Ruptured thymoma causing mediastinal hemorrhage resected via partial sternotomy.

A case of a ruptured thymoma causing mediastinal hemorrhage and hemothorax that was electively resected by a partial sternotomy approach is presented. This case and others previously reported illustrate that a sudden onset of dyspnea and chest pain accompanied by acute mediastinal widening on chest roentgenogram in a previously healthy patient should suggest the diagnosis of a ruptured thymoma. An upper part sternotomy approach may be as safe and effective as a less invasive surgical procedure in resection of noninvasive thymomas, even if dense tumor adhesion exists.

Aged↗
PubMed2001

Ground performance of air conditioning and water recycle system for a Space Plant Box.

Researchers from 5 Japanese universities have developed a plant growth facility (Space Plant Box) for seed to seed experiments under microgravity. The breadboard model of the Space Plant Box was fabricated by assembling subsystems developed for microgravity. The subsystems include air conditioning and water recycle system, air circulation system, water and nutrient delivery system, lighting system and plant monitoring system. The air conditioning and water recycle system is simply composed of a single heat exchanger, two fans and hydrophilic fibrous strings. The strings allow water movement from the cooler fin in the Cooling Box to root supporting materials in the Plant Growth Chamber driven by water potential deficit. Relative humidity in the Plant Growth Chamber can be changed over a wide range by controlling the ratio of latent heat exchange to sensible heat exchange on the cooling fin of the heat exchanger. The transpiration rate was successfully measured by circulating air inside the Plant Growth Chamber only. Most water was recycled and a small amount of water needed to be added from the outside. The simple, air conditioning and water recycle system for the Space Plant Box showed good performance through a barley (Hordeum vulgare L.) growth experiment.

Air Conditioning↗
PubMed2001

The effect of gravity on surface temperature and net photosynthetic rate of plant leaves.

To clarify the effects of gravity on heat/gas exchange between plant leaves and the ambient air, the leaf temperatures and net photosynthetic rates of plant leaves were evaluated at 0.01, 1.0, 1.5 and 2.0 G of 20 seconds each during a parabolic airplane flight. Thermal images of leaves were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 15% and an irradiance of 260 W m-2. The net photosynthetic rates were determined by using a chamber method with an infrared gas analyzer at an air temperature of 20 degrees C, a relative humidity of 50% and a photosynthetic photon flux of 0.5 mmol m-2 s-1. The mean leaf temperature increased by 1 degree C and the net photosynthetic rate decreased by 13% with decreasing gravity levels from 1.0 to 0.01 G. The leaf temperature decreased by 0.5 degree C and the net photosynthetic rate increased by 7% with increasing gravity levels from 1.0 to 2.0 G. Heat/gas exchanges between leaves and the ambient air were more retarded at lower gravity levels. A restricted free air convection under microgravity conditions in space would limit plant growth by retarding heat and gas exchanges between leaves and the ambient air.

Gravitation↗
PubMed2001

Significance of fetal fibronectin and cytokine measurement in the cervicovaginal secretions of women at term in predicting term labor and post-term pregnancy.

OBJECTIVE: To determine whether fetal fibronectin (FFN) or cytokine concentrations in cervicovaginal secretions can be used to predict term labor and post-term pregnancy. STUDY DESIGN: FFN and cytokines were assayed in cervicovaginal mucus from 122 pregnant women at 29-35 weeks and weekly from week 36 to parturition. RESULTS: FFN concentrations were elevated from about 3 weeks before parturition; a correlation was found between FFN levels and sampling-to-delivery intervals. Parturition was best predicted within 7 days of sampling when the FFN value was >or=50ng/ml between 36 and 41 gestational weeks. Interleukin-1beta (IL-1beta) concentrations were elevated from 3 to 4 weeks before parturition; a correlation was found between IL-1beta levels and sampling-to-delivery intervals. Parturition was best predicted within 7 days of sampling, with an IL-1beta cut-off value of >or=100pg/ml. CONCLUSION: Term labor and post-term pregnancy can be predicted within 7 days of sampling, using FFN and IL-1beta concentrations in cervicovaginal secretions of pregnant women.

Adult↗
PubMed2001

Methylene blue as an electrochemical discriminator of single- and double-stranded oligonucleotides immobilised on gold substrates.

Self-assembly of thiol-terminated oligonucleotides on gold substrates provides a convenient and versatile route to DNA-functionalised surfaces. Here we show that the square-wave voltammetric peak position of methylene blue complexed to thiol-terminated single-stranded oligonucleotides immobilised on gold electrodes differs from that of methylene blue complexed to thiol-terminated double-stranded oligonucleotides immobilised on gold electrodes. The peak potential of methylene blue at the single-stranded oligonucleotide array was consistently found to occur at potentials ca. 10-15 mV more positive than that at double-stranded oligonucleotide arrays, the precise difference being dependent on the direction of the voltammetry. This voltammetric behaviour mirrors that found for methylene blue bound to freely diffusing single- and double-stranded calf thymus DNA and suggests that the immobilised oligonucleotides retain the methylene blue binding properties of their freely diffusing counterparts. Thus methylene blue provides a simple electrochemical indicator for the status of oligonucleotide-functionalised gold surfaces.

Animals↗
PubMed2001

Echocardiographic features in a patient with primary oxalosis.

Primary oxalosis is a rare congenital disorder of oxalate metabolism characterized by deposits of calcium oxalate in several organs, including the heart. We present the case of a 38-year-old man with primary oxalosis who had unique echocardiographic findings. Two-dimensional echocardiography revealed the sparkling high intensity echocardiographic pattern and concentric thickening of myocardial walls. Microscopic examinations showed the extensive deposits of calcium oxalate crystals in the myocardium. Therefore, we suggest that primary oxalosis should be given important consideration in the differential diagnosis of a hypertrophied myocardium with high intensity echocardiograms.

Adult↗