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Biomedical subjects

T Imura

Publications and source records attributed to T Imura.

At least 19 recordsLinked to original sources
PubMed1996

Renal functional measurements in young rats with chronic inhibition of nitric oxide synthase.

The purpose of the present study was to examine renal functional changes caused by chronic blockade of nitric oxide (NO) synthesis in young rats. Two types of NO synthase inhibitor were used: NG-nitro-L-arginine methyl ester (L-NAME) as a non-selective inhibitor and aminoguanidine (AG) as a selective inhibitor of the inducible isoform. Oral administration of L-NAME (20-80 mg/dL of drinking water), not AG (400 mg/dL), for 4 weeks induced systemic hypertension in the treated rats. Both inhibitors caused a significant reduction in urinary excretion of NO2-/NO3-. Rats treated with L-NAME developed proteinuria and tubular enzymuria (high excretion of N-acetyl-beta-D-glucosaminidase) in a dose-dependent fashion, with normal serum levels of creatinine, albumin and cholesterol. Chronic AG administration did not alter the urinary levels of protein and N-acetyl-beta-D-glucosaminidase or serum laboratory values. Overall, these observations highlight the importance of the continuous generation of NO by the constitutive isoform in the control of vascular tone and the maintenance of renal glomerular and tubular function. Oral administration of L-NAME may serve as a model of chronic NO-deficient hypertension with renal injury in young rats.

Animals↗
PubMed1996

[The clinical significance of glitter-cells in the urine during urinary tract infection].

To clarify the relationship between glitter-cells and urine osmotic pressure, neutrophils were isolated from venous blood of 4 normal volunteers and incubated in urine specimens with different osmotic pressures. Glitter-cells were detected in the urine with 100-400 mOsm/l. The rate of glitter-cells in neutrophils incubated for 4 hours were significantly less than those incubated for 0 minute (p < 0.05). We clinically investigated the relationship between the presence of glitter-cells in fresh urine and the site of urinary tract infection (UTI) or organisms isolated from urine. Fresh urine samples were obtained from 95 patients (55 male and 40 female). Urine samples were examined for bacteriuria by the quantitative culture method, and significant bacteriuria was defined as more than 10(5)/ml of bacilli for midstream urine or as more than 10(4)/ml for urine collected by catheterization. Leukocytes and glitter-cells in the unspun and unstained urine were counted on a disposable slide using a counting chamber. Patients with upper UTI showed a significantly higher incidence of glitter-cells than patients with lower UTI (p < 0.05). Patients with glitter-cells had a significantly higher incidence of polymicrobial infections than those without glitter-cell (p < 0.05). These findings suggest that patients with glitter-cells in the urine show upper UTI (pyelonephritis) and polymicrobial infections.

Adolescent↗
PubMed1994

Plasma peroxidized low-density lipoprotein with hydroperoxidized cholesteryl linoleates estimated in patients with familial hypercholesterolemia.

A study was conducted to ascertain the presence of peroxidized low-density lipoprotein (LDL) in plasma and to determine the chemical structure of the peroxidized LDL so that the mechanism by which vascular complications develop may be elucidated in patients with familial hypercholesterolemia (FH). Family trees showing hypercholesterolemia and moderate grade thickness of the Achilles' tendon were confirmed in all patients. Cholesteryl ester, triglycerides (TG), free fatty acid (FFA), free cholesterol (FC), and phospholipids in normal LDL were stained on a thin-layer chromatography (TLC) plate, but from peroxidized LDL, spot X1 between TG and FFA, and spot X2 between FFA and FC were identified clearly except for the lipids recognized in normal LDL on the TLC plates. From intermediate-density lipoprotein (IDL), LDL1, and LDL2 of FH patients, spot X1 was clearly recognized. Hydroperoxidized cholesteryl linoleate (HPO-CL) was estimated and identified from Cu(2+)-treated standard CL, Cu(2+)-treated LDL and LDL obtained from FH patients by means of high-pressure liquid chromatography, mass spectrometry, nuclear magnetic resonance, positive reaction of p-methoxydiphenylpyrenyl-phosphine and various chemical reactions. The percentage of HPO-CL to total lipids in LDL was in the order of IDL < LDL1 < LDL2 in FH patients, and it was markedly higher in FH patients when compared to healthy persons. Spot X1 obtained from Cu(2+)-treated CL, from Cu(2+)-treated normal LDL and from LDL of FH patients was chemically identical, consisting of at least 4 kinds of HPO-CL isomer. LDL2-cholesterol levels were higher in FH patients than those of LDL1-cholesterol, whereas in healthy persons LDL1 cholesterol levels were higher compared to those of LDL2 cholesterol. The capacity of LDL2 for peroxidization by Cu2+ was greater than that of LDL1 in healthy persons. Biological functions, such as acceleration of platelet aggregation, great internalization into macrophages and injuries of the arterial endothelia, were reported for LDL with HPO-CL in our previous experiments. Thus, the existence of peroxidized LDL with HPO-CL may be one of the important risks for vascular complications in FH patients.

Adult↗
PubMed1992

MRI of syphilitic myelitis.

MR imaging was performed on a patient with syphilitic myelitis. T2-weighted images showed high intensity areas in the thoracic spinal cord. On T1-weighted images after gadolinium-DTPA injection, heterogeneous enhancement was observed in the superficial portion of the spinal cord. The intramedullary high intensity areas on T2-weighted images disappeared after antibiotic therapy.

Contrast Media↗
PubMed1990

In vivo viscoelastic behavior in the human aorta.

To characterize the viscoelastic properties of the human aorta in vivo, the pressure-diameter relation was determined in the abdominal aorta in 15 subjects. Diameter was measured noninvasively with a highly sensitive ultrasonic displacement meter, while intra-aortic pressure was measured with a catheter tip micromanometer inserted from the femoral artery. The frequency-dependent changes in the pressure-strain modulus (Ep) of the aorta and the phase lag of diameter to pressure were calculated by frequency analysis of these wave forms at the mean blood pressure of 109 mm Hg. The Ep and the phase lag at the fundamental frequency component (1.2 +/- 0.3 Hz, mean +/- SD) were (1.52 +/- 0.57) x 10(6) dyne/cm2 and -6.7 degrees +/- 2.1 degrees, respectively. Although the phase lag at the fundamental frequency was in good agreement with the published in vitro data, the calculated phase lags above the second harmonic were inconsistent, which was probably due to the nonlinearity in the pressure-diameter relation. To separate the effect of this nonlinearity, analysis was conducted with a model consisting of a static nonlinear component representing the elasticity and a dynamic linear component representing the viscosity. This method of analysis revealed that the phase lag due to the viscous component provided relatively flat frequency response to the 10th harmonic. It was confirmed that the aortic wall viscosity showed no apparent difference between the in vivo and the in vitro experimental conditions.

Adult↗
PubMed1990

A cis-acting locus needed for stable maintenance of the yeast plasmid pSB3.

The Zygosaccharomyces rouxii plasmid pSB3 is one of the yeast plasmids resembling 2-microns DNA. The presence of a cis-acting locus needed for stable maintenance of pSB3 has been expected by analogy with the functions encoded by other yeast plasmids such as 2-microns DNA and pSR1. We found such a locus and designated it STB-SB3. The STB-SB3 locus was delimited within 371 bp in a unique region of pSB3. This region is included in the plasmid region where no transcript was detected. No prominent feature of the nucleotide sequence was found in this region except for a direct repeat with 65% homology consisting of 27 bp and 29 bp. This is in clear contrast with the structure of the STB locus of 2-microns DNA which has five and a half tandem repeats consisting of a highly homologous 62 bp sequence. By analyzing the sites hypersensitive to nucleases using partially purified nuclei containing pSB3, the STB-SB3 locus was found not to be tightly folded into a nucleosome structure.

Base Sequence↗
PubMed1988

Possible gene interchange between plasmid and chromosome in yeast.

Genomic DNAs isolated from 420 yeast strains stocked in the Department of Fermentation Technology, Hiroshima University (HUT) were screened for the presence of a plasmid sequence both as plasmid or in the chromosome. Five DNA samples gave rise to a positive hybridization signal when 32P-labelled Zygosaccharomyces plasmid pSR1 was used as a probe. Two among these contain hybridizing sequences as plasmids while the other three apparently were chromosomal. Two chromosomal DNA segments of HUT 7195 (Zygosaccharomyces spp.) which hybridized with pSR1 probe were cloned and sequenced. Both DNAs hybridized with a plasmid sequence covering the P gene of pSR1. One of the two segments contains a large open reading frame which can encode 410 amino acid residues. The deduced amino acid sequence is closely related with that of the P gene of pSR1. The present finding suggests that there was an interchange(s) of a gene between yeast plasmid(s) and chromosomes.

Amino Acid Sequence↗
PubMed1988

Arteriosclerotic change in the human abdominal aorta in vivo in relation to coronary heart disease and risk factors.

In 137 living subjects, arteriosclerotic change in the human abdominal aorta was examined in relation to coronary heart disease (CHD) using a new ultrasonic method. The pressure strain elastic modulus (Ep) was calculated as an index of elastic properties from which arteriosclerotic change in the aorta was estimated. Thirty-one patients with CHD and 36 subjects with hypertension showed progression of the arteriosclerotic change in the abdominal aorta compared with 70 normal controls with the same age distribution (40-60 yrs). The Ep values were 1.03 +/- 0.27 X 10(6) dyne/cm2 in the normal group, and were elevated significantly (P less than 0.001) to 1.81 +/- 0.55 X 10(6) dyne/cm2 in the CHD group, and 1.95 +/- 1.31 X 10(6) dyne/cm2 in the hypertensive group. A significant correlation (r = 0.49, P less than 0.01) between the Ep values of the abdominal aorta and serum total cholesterol was observed in the CHD group. It was shown in living human subjects that the progression of arteriosclerotic change in the abdominal aorta was associated with coronary heart disease, and that some coronary risk factors, such as hypertension and serum total cholesterol, also affected arteriosclerotic change in the abdominal aorta.

Aorta, Abdominal↗
PubMed1987

Yeast plasmids resembling 2 micron DNA: regional similarities and diversities at the molecular level.

The nucleotide sequence of two Zygosaccharomyces plasmids, pSB2 (5,415 base pairs), isolated from Zygosaccharomyces bailii, and pSM1 (5,416 base pairs), isolated from Zygosaccharomyces fermentati Naganishi, was determined. The predicted amino acid sequences of open reading frames among six yeast plasmids that resemble 2 microns DNA indicated regional sequence similarities among FLP proteins. Greater similarities were seen among Zygosaccharomyces plasmids (pSB2, pSB3, pSR1, and pSM1) than other combinations. A putative recognition site for the FLP enzyme of a Zygosaccharomyces plasmid also showed some conservation, especially in the 4 nucleotides flanking the central spacer region. From comparative studies of the sequences of putative genes of each plasmid, we propose an apparent phylogenetic relationship among yeast plasmids resembling 2 micron DNA. Among the Zygosaccharomyces plasmids, pSB2 and pSR1 are most closely related, since not only were the FLP enzymes of these two plasmids most closely related, but also the amino acid sequence of the putative P gene of pSR1 showed clear homology with that of open reading frame B of pSB2.

Amino Acid Sequence↗
PubMed1986

Non-invasive ultrasonic measurement of the elastic properties of the human abdominal aorta.

A new echo tracking device linked to real time ultrasonic B mode equipment was developed to measure non-invasively the elastic properties of the human abdominal aorta. Pulsatile diameter change and mean diameter of the abdominal aorta were measured in 61 subjects with this ultrasonic device. Strain and pressure-strain elastic modulus Ep were calculated from pulsatile diameter change, diameter, and pulse pressure obtained by the auscultatory method. Strain significantly decreased with age; 0.076(0.024) (mean(SD)) in group 1 (20 young adults below the age of 35 years); 0.048(0.024) in group 2 (21 middle aged subjects between the ages of 35 and 60 years); and 0.030(0.010) in group 3 (20 elderly subjects over the age of 60 years). Ep values were 0.99(0.34) X 10(5), 1.55(0.68) X 10(5), and 3.80(2.05) X 10(5) N X m-2 in groups 1, 2, and 3 respectively. Ep in group 3 was significantly higher than in groups 1 and 2. The regression equation relating Ep to age was Ep = (-0.72 + 0.058 X age) X 10(5) N X m-2 (r = 0.73). The Ep value and its age related increase agreed with the findings in postmortem arteries. The elastic properties of the abdominal aorta could, therefore, be determined non-invasively by this ultrasonic method.

Aorta, Abdominal↗
PubMed1985

[Non-invasive measurement of the elastic properties of the abdominal aorta and the analysis of aging change--changes of elasticity of the aorta by aging].

For the purpose of the non-invasive measurement of the elastic properties of human abdominal aorta, we developed high sensitive measurement system of small displacement of tissue. This system consists of phase locked echo tracking loop combined with conventional B-mode imaging. The sensitivity to displacement in the model experiment was in the order of micro meter. Pressure strain elastic modulus (Ep) and stiffness parameter (beta) of abdominal aorta were calculated by our equipment in 61 persons, which were subdivided into 3 age groups, the young group (20 persons less than 35 yrs.), the middle aged group (21 persons between 35 yrs. and 60 yrs.), and the old group (20 persons more than 60 yrs.). Ep in the young group was 0.99 +/- 0.34 X 10(6) dynes/cm2, the middle aged group 1.55 +/- 0.68 X 10(6) dynes/cm2, the old group 3.80 +/- 2.05 X 10(6) dynes/cm2. Beta in the young group was 9.3 +/- 3.3, the middle aged group 12.0 +/- 4.5, the old group 27.6 +/- 14.0. The values of Ep and beta in the old group were significantly different from those in the young group and the middle group. Moreover large deviation of the both values was showed within the old group. The influence of aging on the elastic properties of abdominal aorta was found with large individual variation in relation to the progression of the sclerotic change.

Adult↗