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Biomedical subjects

C Kato

Publications and source records attributed to C Kato.

At least 91 records · Page 5Linked to original sources
PubMed1997

Comparison of the gene expression of aspartate beta-D-semialdehyde dehydrogenase at elevated hydrostatic pressure in deep-sea bacteria.

Aspartate beta-D-semialdehyde dehydrogenase genes (asd) were cloned and sequenced from a deep-sea-adapted strictly barophilic bacterium, Shewanella sp. strain DB6705, and a moderately barophilic bacterium, Shewanella sp. strain DSS12. The determined asd sequences of these two strains were very similar, and the identity of the deduced amino acids sequences was 96.2%. The 5'-ends of the asd mRNA from both strains were localized at corresponding sites by primer extension analysis, and two transcriptional starting points, which differed by only 1 base, were detected. In strain DB6705, a pressure-regulated transcript was mainly observed, whereas in strain DSS12, a pressure-tolerant transcript was observed together with the pressure-regulated transcript. Western-blotting analysis showed that the ASD protein was expressed under higher pressure conditions in DB6705, and under all pressure conditions tested in DSS12, as reflected in the primer extension results. Our findings suggest that asd expression controlled by pressure is one of the important mechanisms involved in the adaptation of microorganisms to the deep-sea environment.

Adaptation, Physiological↗
PubMed1997

[Echocardiographic prediction of risk for embolism in patients with infective endocarditis].

The relationship between two-dimensional echocardiographic findings of vegetation and embolic events was investigated in 26 patients with infective endocarditis (17 males and 9 females, mean [+/-SD] age 51 +/- 17 years). The size and the other morphologic characteristics of vegetation (mobility, extent and consistency) were analyzed retrospectively according to the criteria by Sanfilippo, et al., and parameters were assigned scores from 1 to 4 to provide a total score. Patients with a maximum vegetation diameter > 10 min had a significantly higher incidence of embolic events than those with < or = 10 mm (p < 0.05). Each parameter of vegetation showed no significant difference between patients with and without embolic events; but the total score was significantly higher in patients with embolic events (p < 0.05). Particularly, all patients with a total score > or = 10 had embolic events, whereas those without embolic events had a total score < or = 9. There were no significant differences in the frequency of emergent valve replacement between patients with aortic value and mitral valve endocarditis. However, the incidence of heart failure was higher, but not significantly, in patients with aortic valve (67%) and combined valve endocarditis (67%) than in those with mitral valve endocarditis (36%). The maximum size and total score reflecting mobility, extent and consistency of vegetation using two-dimensional echocardiography provide useful information to predict the occurrence of embolic events in patients with infective endocarditis.

Adult↗
PubMed1997

[Comparison of effects of thrombolytic therapy followed by elective coronary intervention and direct coronary intervention in acute myocardial infarction: usefulness of dobutamine stress echocardiography].

The effects of intravenous administration of tissue plasminogen activator (t-PA) followed by elective percutaneous transluminal coronary angioplasty (PTCA) were compared to those of direct PTCA (d-PTCA) in patients with acute myocardial infarction using dobutamine stress echocardiography 1 week and 1 month after the acute episode. There were 12 patients in the t-PA group and nine patients in the d-PTCA group. Dobutamine was infused at incremental doses (5 micrograms/kg/min for each 5 min step). Wall motion changes were classified during infusion into four patterns, improvement, biphasic, worsening and no change. One week after the acute episode, seven of 12 patients in the t-PA group showed biphasic the pattern and five showed the improvement pattern. The biphasic pattern was observed in three patients in the d-PTCA group, worsening in one and improvement in five. One month later, the biphasic pattern in five patients in the t-PA group changed to the improvement pattern. No patients in the d-PTCA group showed changes in the wall motion pattern. There was no difference between the two groups in the frequency of the change of wall motion patterns 1 week and 1 month after infarction, but the improvement pattern was significantly increased from five to 10 patients in the t-PA group after 1 month (p < 0.05). The sensitivity, specificity and accuracy of the biphasic pattern in the t-PA group for indicating remnant coronary stenosis were 78%, 100% and 83%, respectively. Evaluation of wall motion pattern by dobutamine stress echocardiography is useful for assessment of reperfusion therapy for acute myocardial infarction. The administration of t-PA followed by elective PTCA has similar efficacy to d-PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1996

Characterization of a ligand for receptor protein-tyrosine kinase HTK expressed in immature hematopoietic cells.

HTK is a receptor tyrosine kinase that belongs to the Eph subfamily. An extensive screening using BIAcore system revealed that a colon cancer cell line, C-1, expressed the ligand for HTK. From the conditioned medium of C-1 cells, a soluble form of ligand was purified by receptor affinity chromatography, and the isolation of full-length cDNA revealed that this ligand is identical to the human HTK ligand (HTKL) previously reported. HTK receptor tyrosine phosphorylation was induced by membrane-bound or clustered soluble HTKL but not by unclustered soluble HTKL, indicating that HTKL requires cell-to-cell interaction for receptor activation. Binding analysis demonstrated that HTKL binds to HTK with a much higher affinity (Kd: 1.23 nM) than the other transmembrane-type ligand for Eph family, LERK-2/ELKL (Kd: 135 nM). The expression of HTK in cord blood cells was upregulated after the culture in the presence of stem cell factor. Clustered soluble HTKL stimulated the proliferation of sorted HTK+ cord blood cells and a hematopoietic cell line, UT-7/EPO from which HTK was isolated. These findings suggest the involvement of HTK-HTKL system in the proliferation of HTK+ hematopoietic progenitor cells in the hematopoietic environment.

Amino Acid Sequence↗
PubMed1996

Molecular cloning of the gene encoding RNA polymerase alpha subunit from deep-sea barophilic bacterium.

We have cloned the gene encoding RNA polymerase alpha subunit from a gene library of deep-sea barophilic bacterium strain DB6705. The clone contains the genes for ribosomal protein S4, RNA polymerase subunit alpha and ribosomal protein L17 in this order. The alpha gene has 328 amino acids and a molecular mass of 36 100 Da with 86.9% identity to Escherichia coli alpha gene. Differences between the two sequences were mainly in the N-terminal portion of the alpha subunit, which is involved in the assembly of the core RNA polymerase; while the 87 C-terminal residues, which form a region involved in contact with some positive regulators and rrnB P1 promoter region called UP-element, were identical in the both strain. Plasmid encoding the alpha subunit with an N-terminal hexahistidine tag was constructed. Using the plasmid, the recombinant fusion alpha subunit was overexpressed and successfully purified to near homogeneity.

Amino Acid Sequence↗
PubMed1996

Culturability and survival of an extreme thermophile isolated from deep-sea hydrothermal vents

The culturability of a strictly anaerobic, extremely thermophilic archaeon, Thermococcus peptonophilus (optimal growth temperature: 85&deg; C), was studied during survival stages at various temperatures (98, 85, 70, and 4&deg; C). Total cell number (determined by DAPI staining), active cells (rhodamine-stained cells), and culturable cells (using most-probable-number) were counted over time. The number of culturable cells decreased under each condition tested. The total number of cells significantly decreased only at temperatures close to the maximum for growth (98&deg; C); at this temperature, the cells spontaneously lysed. Our results suggested that survival at 4&deg; C in oxygenated waters might be a mechanism for the dispersion of extreme thermophiles in the ocean. In addition, we proved the existence of T. peptonophilus cells in several physiological states: culturable cells, active non-culturable cells, inactive non-culturable cells, and dead cells. Cell death was caused by cellular lysis.

Journal Article↗
PubMed1996

High pressure represses expression of the malB operon in Escherichia coli.

The formation of plaques by lambda phage in Escherichia coli was prevented by elevated hydrostatic pressure; phage plaques were not detected at 30 MPa. Furthermore, using promoter fragments derived from the malB operon, we showed that gene expression initiated from both promoters (malK-lamB and malEFG) was repressed by elevated hydrostatic pressure. Our findings suggest that high pressure affects gene expression directed by the malB regulatory interval, and this may cause a decrease in the quantities of lambda receptor protein, LamB.

Atmospheric Pressure↗
PubMed1996

Differences between 99mTc-DTPA and 99mTc-MAG3 captopril renographies in renovascular hypertension.

Captopril renography (CRS) with 99mTc-DTPA and 99mTc-MAG3 was performed on a 21-year-old woman with renovascular hypertension due to right renal artery stenosis caused by fibromuscular dysplasia. In the affected kidney, the renogram pattern was substantially changed with 99mTc-DTPA and 99mTc-MAG3 following the administration of captopril, and the quantitated renal uptake indicating individual renal function was significantly decreased in 99mTc-DTPA and slightly decreased in 99mTc-MAG3. In the contralateral normal kidney, the renogram showed some minor changes with both radioagents, while the quantitated renal uptake was significantly decreased with 99mTc-DTPA and substantially increased with 99mTc-MAG3. The combined use of physiologically different renal agents 99mTc-DTPA and 99mTc-MAG3 is helpful in investigating hemodynamic and functional changes in the stenosed kidney as well as the normal kidney in RVH.

Adult↗
PubMed1996

Isolating and characterizing deep-sea marine microorganisms.

We have isolated several microorganisms that are adapted to living in the extremes of the deep-sea environment. They include barophilic bacteria, which are able to grow at high hydrostatic pressure, but that are unable to grow at atmospheric pressure, and organic-solvent-tolerant bacteria, which are able to grow in the presence of toxic organic solvents such as toluene or benzene. In this review, we describe how to isolate such extremophiles, and we outline the characteristics of several strains that have been recovered from the deep-sea environment.

Bacteria↗
PubMed1996

Open reading frame 3 of the barotolerant bacterium strain DSS12 is complementary with cydD in Escherichia coli: cydD functions are required for cell stability at high pressure.

Escherichia coli strain JD518, a cydD-deficient mutant, displayed temperature-sensitive and pressure-sensitive growth. The defective cydD gene in this strain was complemented by open reading frame 3 (ORF3), previously identified in DNA from a barotolerant bacterium, strain DSS12, allowing growth of the cydD mutant under high temperature and high pressure conditions. Spectrophotometrical analysis indicated that the cytochrome bd complex which is assembled by the CydD protein was expressed in E. coli strain JD518 carrying the ORF3 gene at the same level as occurred in the wild-type strain. Our results indicate that the cydD gene functions are required for cell stability under the condition of high pressure stress in bacteria.

ATP-Binding Cassette Transporters↗
PubMed1996

[False-positive increase in 1,5-anhydro-D-glucitol due to Kampo (Japanese herbal) medicine].

We report a case presenting with a remarkable increase in blood 1,5-anhydro-D-glucitol (AG) upon taking a Kampo (Japanese Herbal) Medicine, Ninjin-Youei-To. The HPLC-analysis of the drug taken by the present case revealed 8.8 mg/g of AG in this Kampo (Japanese Herbal) Medicine. A similar increase in blood AG(maximum increase: 1.49 micrograms/mL/day) was observed when healthy normal volunteer's took Ninjin-Youei-To alone. Drug withdrawal led to a decrease in blood AG. No great change in diabetes-related items measured at the same time was noted, and glycosuria was always negative. These results led us to consider that the change in blood AG is not diabetic, but Ninjin-Youei-To-mediated. Ninjin-Youei-To is composed of 12 kinds of crude drugs, including Ginseng radix and Polygalae radix, and we made a search of the literature concerning these crude drugs. Polygalae radix, a component of Ninjin-Youei-To, was confirmed to contain AG. Where a change in blood AG does not accord with clinical symptoms and other laboratory findings, some influence or other of Kampo (Japanese Herbal) Medicine should be taken into account as a pre-analytical phase error.

Aged↗
PubMed1996

[The effect of calcium antagonist on ischemia-reperfusion injury of the rabbit retina].

We investigated the effect of nicardipine (NC), a calcium antagonist, on retinal ischemia-reperfusion injury. Electroretinogram (ERG) was recorded from rabbit eyes before and after ischemia produced by increasing intraocular pressure to 140 mmHg for 90 min after giving 0.01% NC (0.1 ml) intravitreally (n = 4). ERGs from intact (non-ischemic) rabbit eyes after injecting NC intravitreally was also recorded (n = 4) (NC group). The recovery rate of b-wave amplitude after reperfusion was significantly higher in the NC group than in the control group which was given saline without NC (p < 0.05). There were no significant differences between the NC and the control groups in a-wave amplitude and implicit time of the b-wave. No significant changes were detected in the a-wave or b-wave amplitude after intravitreal injection of NC into the intact eyes. We suggest that NC can prevent ischemia-reperfusion injury of the rabbit retina and could be considered for clinical use.

Animals↗
PubMed1995

High pressure influences on gene and protein expression.

Elevated hydrostatic pressure can influence gene and protein expression in both 1 atmosphere-adapted and high pressure-adapted microorganisms. Here we review experiments documenting these effects and describe their significance towards understanding the molecular bases of life in deep-sea high pressure environments.

Bacterial Proteins↗
PubMed1995

Expressing kidney uptake during 99Tcm-MAG3 renography in terms of administered activity.

In a study of gamma-camera renography, a digitized time-activity curve, or renogram, was standardized in terms of absolute renal uptake. The algorithm for standardization of the renogram was based on a gamma-camera uptake method employed by Gates and Schlegel et al. All count rates for the background-corrected renograms were converted to percent renal uptake per injected dose per minute (%RU). The maximum value for the scale on the y-axis was set at 20% RU. The renograms were generated from 66 kidneys in 35 patients (27 males, 8 females) aged 19-80 years. Using the newly developed computer program, the shape of the renograms was considered abnormal between 8/52 (15%) and 10/53 (19%) kidneys, depending on the observer, all of which were classified as normal when displayed conventionally. All the renograms for 4 patients with one poorly functioning kidney, and between 8 (28%) and 10 (32%) renograms for 31 patients with two poorly performing kidneys, exceeded the maximum g-axis value of 20% RU. Expression of the renograms based on absolute uptake is helpful in avoiding the potential problem of two poorly functioning kidneys, which may be considered near-normal in terms of count rate. The maximum value on the y-axis in 99Tcm-MAG3 renography should be fixed between 25 and 30% RU, while the actual amplitude of the standardized renogram may depend on the method used for quantification.

Adult↗