Biomedical subjects

E Noguchi

Publications and source records attributed to E Noguchi.

At least 55 records · Page 3Linked to original sources

PubMed1998

[Quantification of regional cerebral blood flow at the control state and loaded with diamox using split-dose 99mTc-ECD SPECT and venous blood samples].

The purpose of the study is to develop a simple and less invasive method for quantifying regional cerebral blood flow (rCBF) at pre- and post Diamox test using split-dose 99mTc-ECD and SPECT. By employing a microsphere model, integral of input function was calculated by the one-point venous sampling method previously reported. The study was performed on 5 subjects with cerebrovascular diseases. A split dose of 99mTc-ECD was injected pre- and post Diamox injection, and rCBF was measured by two SPECT scans and single venous samples, respectively. Mean CBF obtained by the present method was 0.47 +/- 0.07 ml/g/min at the control state, and 0.63 +/- 0.12 ml/g/min loaded with Diamox (mean % increase; 35%), showing good agreement with those obtained by the 133Xe-inhalation method. Since the present method does not require arterial blood sampling, dynamic data acquisition and dose corrections, it is simple, less invasive and useful in clinical SPECT studies.

Acetazolamide↗

PubMed1998

[A study on accuracy of rCBF measurements loaded with acetazolamide based on the microsphere model using iodine-123-IMP SPECT].

We studied the accuracy of the method for measuring regional cerebral blood flow (rCBF) loaded with acetazolamide based on the microsphere model using iodine-123-IMP (IMP) SPECT. Two methods were examined, the super-early microsphere method with continuous withdrawal of arterial blood using the SPECT image obtained 5 min after tracer injection and the early microsphere method with one-point arterial sampling using the SPECT image obtained 30 min postinjection. On five subjects, after acetazolamide administration we measured rCBF by the analysis based on the two-compartment model using the data derived from dynamic SPECT scans and the sequential arterial blood sampling after IMP injection. Values of rCBF obtained by both super-early microsphere method and early microsphere method were significantly correlated with those obtained by the two-compartment model analysis (r = 0.982, 0.930, respectively). We conclude that it is possible to use the method based on the microsphere model in measuring rCBF loaded with acetazolamide. The early microsphere method with one-point sampling should be used clinically because of its simplicity and less-invasiveness.

Acetazolamide↗

PubMed1998

[Comparison of the vascular effects of propofol and those of thiopental in patients under cardiopulmonary bypass].

The effects of propofol (1 mg.kg-1) and thiopental (2.5 mg.kg-1) on the vascular smooth muscle were investigated in 10 cardiac patients on cardiopulmonary total bypass using a constant perfusion flow. Radial mean arterial blood pressure (mAP) decreased to 85 +/- 5% (P < 0.01, vs preinjection) in the post-injection late phase (2-3 min) after propofol, and to 90 +/- 6% (P < 0.01) after thiopental. MAP after thiopental showed a transient initial increase to 115 +/- 8% (P < 0.01) in the post-injection early phase (-1 min). Skin blood flow (SBF) in the middle finger-tip increased to a peak of 450 +/- 120% (P < 0.01) in the post-injection late phase after propofol, and to 240 +/- 60% (P < 0.05) after thiopental. The increase in SBF after propofol was greater than that after thiopental (P < 0.05). The decrease in mAP and the increase in SBF under the constant perfusion flow are considered mainly due to a direct drug action of dilating peripheral vessels. In conclusion, this in vivo human study suggests that propofol (1 mg.kg-1) causes more potent vasodilatation in the peripheral vessels than thiopental (2.5 mg.kg-1).

Aged↗

PubMed1998

[Quantification of cerebral blood flow with 99mTc-ECD SPECT based on a 3-compartment model].

In the present study we developed a method for quantifying regional cerebral blood flow (rCBF) using 99mTc-ECD SPECT based on a 3-compartment model. The dynamic SPECT scanning and sequential sampling of arterial blood were performed on 12 subjects with cerebrovascular diseases and etc. We defined brain fractionation index (BFI) as a parameter of rCBF, which was obtained from a single SPECT data and arterial input. The relationship between the values of BFI and rCBF obtained by the 133Xe inhalation method was analyzed by approximation with exponential function. In this method, rCBF was calculated from the values of BFI using the inverse function of the exponential function as a regression curve. The method was applied seven other patients with cerebrovascular diseases and the values of rCBF were compared with those obtained by the 133Xe inhalation method. We observed a good correlation (r = 0.854), and the inclination was approximately 1. This method can be applied to not only large field SPECT cameras but also conventional SPECT cameras.

Adult↗

PubMed1997

Kinetic and stoichiometric analysis for the binding of Escherichia coli ribonuclease HI to RNA-DNA hybrids using surface plasmon resonance.

To understand how ribonucleases H recognize RNA-DNA hybrid substrates, we analyzed kinetic parameters of binding of Escherichia coli RNase HI to RNA-DNA hybrids ranging in length from 18 to 36 base pairs (bp) using surface plasmon resonance (BIAcoreTM). The kon and koff values for the binding of the enzyme to the 36-bp substrate were 1.5 x 10(6) M-1 s-1 and 3.2 x 10(-2) s-1, respectively. Similar values were obtained with the shorter substrates. Using uncleavable 2'-O-methylated RNA-DNA substrates, values for kon and koff were 2.1 x 10(5) M-1 s-1 and 1.3 x 10(-1) s-1 in the absence of Mg2+ that were further reduced in the presence of Mg2+ to 7.4 x 10(3) M-1 s-1 and 2.6 x 10(-2) s-1. Kinetic parameters similar to the wild-type enzyme were obtained using an active-site mutant enzyme, Asp134 replaced by Ala, whereas a greatly reduced on-rate was observed for another inactive mutant enzyme, in which the basic protrusion is eliminated, thereby distinguishing between poor catalysis and inability to bind to the substrate. Stoichiometric analyses of RNase HI binding to substrates of 18, 24, 30, and 36 bp are consistent with previous reports suggesting that RNase HI binds to 9-10 bp of RNA-DNA hybrid.

Alanine↗

PubMed1997

Yrb2p, a Nup2p-related yeast protein, has a functional overlap with Rna1p, a yeast Ran-GTPase-activating protein.

The Ran-GTPase cycle is important for nucleus-cytosol exchange of macromolecules and other nuclear processes. We employed the two-hybrid method to identify proteins interacting with Ran and the Ran GTP/GDP exchange factor. Using PRP20, encoding the Ran GTP/GDP exchange factor, we identified YRB1, previously identified as a protein able to interact with human Ran GTP/GDP exchange factor RCC1 in the two-hybrid system. Using GSP1, encoding the yeast Ran, as bait, we isolated YRB2. YRB2 encodes a protein containing a Ran-binding motif similar to that found in Yrb1p and Nup2p. Yrb1p is located in the cytosol whereas Nup2p is nuclear. Similar to Yrb1p, Yrb2p bound to GTP-Gsp1p but not to GDP-Gsp1p and enhanced the GTPase-activating activity of Rna1p. However, unlike Yrb1p, Yrb2p did not inhibit the nucleotide-releasing activity of Prp20p. While overproduction of Yrb1p inhibited the growth of a mutant possessing a PRP20 mutation (srm1-1) and suppressed the rna1-1 mutation, overproduction of Yrb2p showed no effect on the growth of these mutants. Disruption of YRB2 made yeast cold sensitive and was synthetically lethal with rna1-1 but not with nup2delta. Nuclear protein import and the mRNA export were normal in strains possessing mutations of YRB2. We propose that Yrb2p is involved in the nuclear processes of the Ran-GTPase cycle which are not related to nucleus-cytosol exchange of macromolecules.

Base Sequence↗

PubMed1997

IgE responsiveness to Dermatophagoides farinae in asthma and atopic dermatitis.

Using Western blotting and RAST, this study examined IgE reactivities to Dermatophagoides farinae (Df) extract in three groups of children with either asthma, atopic dermatitis (AD) or a combination of both. The Df antigen presented at least nine distinct IgE-binding bands, with apparent molecular weights of 15, 25, 30, 40, 48, 59, 67, 80 and 110 kD. Positive IgE binding reactions to 15-kD proteins were found in more than 85% of subjects in all three groups, and positive reactions to 25-, 30- and 110-kD proteins in 35-45% in each group. The frequencies of positive IgE binding reaction to other components were generally low in all three groups. The pattern of IgE reactivity to Df components did not differ significantly between the three groups of subjects. IgE-binding activities to two major allergens, Der f1 and Der f2, were also examined by RAST, using recombinant antigens. High RAST reactivities to Der f1 and Der f2 were found in three groups, and the average RAST levels for Der f1 and Der f2 did not differ significantly between the three groups. These findings suggest that a difference in IgE responsiveness to house dust mite antigen is not a major discriminative factor in determining the difference between asthma and AD.

Adolescent↗

PubMed1997

Evidence for linkage between asthma/atopy in childhood and chromosome 5q31-q33 in a Japanese population.

Susceptibility to the development of asthma and other atopic diseases is known to be associated with genetic components, and several candidate genes have been reported to be linked to atopy in Caucasian populations. We conducted a study of linkage between asthma and markers on chromosomes 5q31-q33 and 11q13 in 68 Japanese families (306 members) by affected sib-pair analysis. Families for the linkage study were ascertained through asthmatic children visiting the allergy clinic. The results provide supportive evidence for linkage between asthma and gene markers in or near the interleukin-4 (IL-4) gene, the IL-9 gene, and D5S393 on chromosome 5q31-q33 (p = 0.0013, p = 0.018, and p = 0.0077, respectively). Linkage between atopic phenotype and these genetic markers was also suggested (p = 0.006, p = 0.01, and p < 0.0001 for atopy, respectively). However, we failed to find evidence for linkage of asthma or atopy to the IgE high-affinity receptor gene on 11q13 (p > 0.1). These findings indicate that beyond ethnicity, there are specific loci that contribute to susceptibility to atopy on chromosome 5q31-q33. In addition, our findings suggest that loci on chromosome 5q31-q33 are linked to the development of asthma in childhood.

Adolescent↗

PubMed1997

Distribution of IgE and IgG antibody levels against house dust mites in schoolchildren, and their relation with asthma.

Although asthmatic patients are known to have increased levels of IgG antibody against house dust mite (HDM), it is not clear whether or not the presence of HDM-specific IgG antibody is associated with the etiological mechanism of asthma. To address this problem, we evaluated the relationship between HDM-specific IgG antibody levels and incidence of asthma in a general pediatric population. IgE and IgG antibody levels against Dermatophagoides farinae (Df) were examined by RAST and ELISA in a total of 722 randomly selected schoolchildren including 26 subjects with asthma, and the relative prevalence rates of asthma in this population were evaluated in relation to both Df-specific IgE and IgG levels. The incidence of asthma correlated not only with levels of Df-specific IgE, but also with those of Df-specific IgG. There was a significant correlation between Df-specific IgE and IgG levels both in the total population and in the asthmatic children. Because IgG and IgE responses occurred in parallel in this population, the clinical significance of HDM-specific IgG anti-body remains unclear. However, our findings have suggested that clinical expression of asthma in children is primarily dependent on their capacity to mount a immune response to HDM, which includes both IgE and IgG responses.

Adolescent↗

PubMed1997

[A comparative study of the quality of SPECT images obtained by 123I-IMP, 99mTc-HMPAO and 99mTc-ECD].

The purpose of this study was to comparatively evaluate the quality of SPECT images for the mapping of rCBF using three tracers, 123I-IMP, 99mTc-HMPAO and 99mTc-ECD. We performed three SPECT studies on seven patients with various cerebral diseases under the same conditions. An effect of Lassen's correction on SPECT images obtained by HMPAO was also evaluated. The same irregular regions of interest were placed on the four transaxial SPECT images. To quantitatively evaluate the pattern of tracer uptake and image contrast, the uptake ratio, regional count/mean count of the cerebrum, and its coefficient variations (CV) were defined, respectively. The order of the value of CV was HMPAO with correction > IMP > ECD > HMPAO without correction. HMPAO with correction showed the best image contrast, but HMPAO without correction was the worst. Uptake ratios of ECD and HMPAO with correction were decreased in the brain stem and thalamus in comparison with those of IMP. Both uptake ratios of ECD and HMPAO without correction were increased in the occipital cortex. IMP provides high quality SPECT images. Images obtained by HMPAO should be modified by Lassen's correction to increase image contrast. ECD or HMPAO should not be used to evaluate patients with spinocerebellar degeneration.

Aged↗

PubMed1997

[A limitation of the split-dose method for evaluating rCBF changes using 99mTc-ECD and SPECT].

The purpose of the study is to validate the split-dose method corrected with dose ratio of 99mTc-ECD for brain perfusion scan. A dose of 600 MBq of 99mTc-ECD was divided into two with various dose ratios from 1:1 to 1:4, and injected to eleven patients with various cerebral diseases. A lesser dose of 99mTc-ECD was injected under a control state for the first SPECT scan, and 15 min SPECT scan was performed 10 min after injection with a triple-head high resolution gamma camera. After the scan, the other dose of 99mTc-ECD was injected under the same control state and the second SPECT scan was performed as same as above. A ratio of the activity of the first scan to the net activity of the second scan corrected by dose ratio, defined as K, was measured in brain regions of each subject. Expected value of K was 1, but the value was distributed with large variations in each subject. The mean % error of the K value was 10.4 +/- 4.9%. Hence it is considered that activity changes by more than 20% from the control values should be required to detect a significant rCBF change in an activation SPECT study. Then, we proposed a new method in which the activity of both two SPECT scans was normalized by cerebellar or occipital activity and compared. The ratio obtained by the proposed method came closer to 1 with less variations and with less mean % error in comparison with those of K value obtained by the dose-correction method. Although the proposed method has a limitation in the use of an activation study loaded with Diamox, it may be useful to evaluate an alteration of rCBF in the study such as postural testing or finger-moving test.

Brain↗

PubMed1997

[Quantification of cerebral blood flow with 99mTc-ECD SPECT by a single arterial or venous blood sample].

The purpose of the study is to develop a simple and less invasive method for quantifying regional cerebral blood flow (rCBF) using 99mTc-ECD and SPECT. By employing a microsphere model, a new method to measure rCBF was developed, which required a single arterial or venous sample instead of continuous withdrawal of arterial blood. Using a regression line, the integral of input function of arterial blood from 0 to 30 min was inferred by activity of arterial blood sampled at time t; A(t), by activity multiplied by its octanol extraction rate; AN(t), by activity of venous blood at time t; V(t), and by activity multiplied by its octanol extraction rate; VN(t). The optimum sampling time of arterial or venous blood was examined when mean % error for inference became minimum. Consequently, minimum error of AN(6 min) was 5.5%, A(3 min) was 8.9%, VN(6 min) was 5.9%, and V(20 min) was 10.0%. Quantitative measurement of rCBF using the value of VN(6 min) was performed on other 6 subjects with dementia etc. To validate the method, 133Xe inhalation SPECT studies were also performed on the same subjects. We found a good agreement between them (r = 0.851). The presented one-point sampling methods were simple and less invasive for quantifying rCBF.

Adult↗

PubMed1996

Dis3, implicated in mitotic control, binds directly to Ran and enhances the GEF activity of RCC1.

Using the two-hybrid method, we isolated a Saccharomyces cerevisiae cDNA encoding a protein homologous to Schizosaccharomyces pombe protein Dis3sp, using as bait, human GTPase Ran. The DIS3 gene is essential for viability and complements S.pombe mutant dis3-54 which is defective in mitosis. Although Dis3sc has no homology to RanBP1, it bound directly to Ran and the S.cerevisiae Ran homologue Cnr1, but not to the S.cerevisiae RCC1 homologue Srm1. Upon binding to Ran with a 1:1 molar ratio, Dis3sc enhanced a nucleotide-releasing activity of RCC1 on Ran. In the presence of Dis3sc, the K(m) of RCC1 on Ran decreased by half, while the kcat was unchanged. In vivo, Dis3sp was present as oligomers of M(r) 670-200 kDa as previously reported, and the 200 kDa oligomer of Dis3sp was found to include Spi1 and Pim1, the S.pombe homologues of Ran and RCC1, respectively. Although the biological function of the heterotrimeric oligomer consisting of Dis3, Spi1 and Pim1 is unknown, our results indicate that Dis3 is a component of the RCC1-Ran pathway.

Amino Acid Sequence↗

PubMed1996

D-type cyclin expression is decreased and p21 and p27 CDK inhibitor expression is increased when tsBN462 CCG1/TAFII250 mutant cells arrest in G1 at the restrictive temperature.

BACKGROUND: The tsBN462 temperature-sensitive mutant hamster cell line exhibits cell cycle arrest and apoptosis at the restrictive temperature of 39.5 degrees C, due to a point mutation in the CCG1/TAFII250 gene, which encodes a component of the general transcription factor TFIID. RESULTS: We now report that CCG1/TAFII250 persisted as a complex with TBP and associated proteins (TAFs) in tsBN462 cells at the restrictive temperature. FACScan analysis revealed that the tsBN462 mutation resulted in a failure to progress out of G0 into G1. Using two-dimensional gel electrophoresis we observed a decrease in the synthesis of several proteins, starting in the middle of the G1 phase, becoming very pronounced during late G1. The expression of the immediate early genes c-fos, c-jun and c-myc was normally induced by serum treatment of quiescent cells at the restrictive temperature, whereas expression of cyclins A, D1 and D3 was reduced. Expression of the cyclin-dependent kinase (CDK) inhibitor proteins p21 and p27 was enhanced. Consistent with the decreased cyclin D and increased p21/p27 expression, we found that phosphorylation of Rb was decreased at 39.5 degrees C. Cyclin A-, E- and Cdk2-associated histone H1 kinase activity was reduced concomitantly with the increase in p21 protein. CONCLUSION: Decreased cyclin/Cdk kinase activity and decreased Rb phosphorylation are possible causes of G1 cell cycle arrest in tsBN462 cells at the restrictive temperature.

Animals↗

PubMed1996

Treatment of whole houses with liquid nitrogen for control of dust mites.

A large volume of liquid nitrogen, (120-150 L) was applied to the houses of 4 asthmatic patients, and the mite densities of the floor dust from these houses were monitored every 2 wk for 4 mo from July to November 1989. The 1st liquid nitrogen treatment was applied in early August and decreased the mite densities to 20-44% of the pretreatment level in all cases, but they returned to the pretreatment level 3-4 wk later (on 3 occasions). The 2nd liquid nitrogen treatment was applied in early September and decreased the mite densities to 6-27% of the pretreatment level within 3 wk in all cases. However, mite numbers again increased to the pretreatment level 4 wk after treatment. The 3rd treatment was applied in mid-October and reduced the mite densities to < 6% of the pretreatment level within 2 wk, and mite numbers remained low thereafter. The results suggested that using liquid nitrogen to freeze houses reduces mite numbers, but that mite recolonization of the houses is an important problem.

Animals↗

PubMed1996

Comparisons of IgE, IgG, and IgG4 responsiveness to Dermatophagoides farinae in children by immunoblotting.

Although asthmatic children are often sensitized to the house-dust mite (HDM) during early childhood, it is not clear what antigenic components are associated with the early immune response of these children. To investigate this problem, we evaluated IgE, IgG, and IgG4 antibody responses to Dermatophagoides farinae (Df) by immunoblotting among three groups of children: group I aged 0-4 years, group II aged 5-9 years, and group III aged 10-14 years. In the group I subjects, positive IgE-binding reactions to 15- and 25-kDa components were found in 76% and 44% of sera, respectively. Those to other components were generally low in frequency. In contrast, positive IgG-binding reactions to 15- and 25-kDa components were found in 44% and 24% of sera, and those to 30- and 110-kDa components in 48% and 88% of sera, respectively. Positive IgG4 reactions to 15- and 25-kDa components were found in 48% and 24%, respectively, and those to other components were very low. Positive IgE-binding reactions to these components gradually became more frequent with increasing age in groups II and III, while IgG and IgG4 reactivities were not markedly different in these age groups. These results suggest that the 15- and 25-kDa proteins of Df are important antigens associated with the initial IgE response to HDM in early childhood, while the 30- and 110-kDa proteins are associated with IgG and 15-kDa components with IgG4.

Adolescent↗

PubMed1996

IgE responsiveness to Dermatophagoides farinae in young asthmatic children: IgE binding study using recombinant allergens of Der f1, Der f2 and mutant proteins of Der f2.

IgE reactivities to two recombinant (r) allergens, rDer f1 and rDer f2, synthetized by cDNA clones from Dermatophagoides farinae (Df) were analyzed using sera of Df-sensitive asthmatic patients of varying ages. Positive RAST responses to rDer f1 and rDer f2 were found in 88 and 80%, respectively, with sera from young asthmatic children aged 0-1, positive RAST rates to these antigens increased to 100% up to 5 years of age. There was a significant correlation between RAST levels of rDer f1 and rDer f2 in these young children aged 0-1. IgE reactivities to four mutant proteins of rDer f2, which have at least one amino acid substitution, were similarly examined in the asthmatic sera. IgE reactivity to D7A, in which Asp7 was replaced by Ala, was reduced to 30-60% compared to the rDer f2. IgE binding to C8/119S, in which both Cys8 and Cys119 were replaced by Ser, lacking a disulfide bond between Cys8 and Cys119, was reduced almost to a background level at all ages. In contrast, A72L and A120L, in which Ala72 and Ala120 were substituted for Leu, respectively, almost retained the same IgE binding activity as the rDer f2 at all ages. These results suggest that Der f1 and Der f2 are important antigens associated with early sensitization to house dust mite in young asthmatic children. In addition, the disulfide bond between Cys8 and Cys119 and the N-terminal region including the 7th amino acid residue are considered to maintain IgE epitopes of the Der f2 allergen.

Adolescent↗

PubMed1996

Putative GTPase Gtr1p genetically interacts with the RanGTPase cycle in Saccharomyces cerevisiae.

In order to identify a protein interacting with RCC1, a guanine nucleotide-exchange factor for the nuclear GTPase Ran, we isolated a series of cold-sensitive suppressors of mtr1-2, a temperature-sensitive mutant of the Saccharomyces cerevisiae RCC1 homologue. One of the isolated suppressor mutants was mutated in the putative GTPase Gtr1p, being designated as gtr1-11. It also suppressed other alleles of mtr1-2, srm1-1 and prp20-1 in contrast to overexpression of the S. cerevisiae Ran/TC4 homologue Gsp1p, previously reported to suppress prp20-1, but not mtr1-2 or srm1-1. Furthermore, gtr1-11 suppressed the rna1-1, temperature-sensitive mutant of the Gsp1p GTPase-activating protein, but not the srp1-31, temperature-sensitive mutant of the S. cerevisiae importin alpha homologue. mtr1-2, srm1-1 and prp20-1 were also suppressed by overexpression of the mutated Gtr1p, Gtr1-11p. In summary, Gtr1p that was localized in the cytoplasm by immunofluoresence staining was suggested to function as a negative regulator for the Ran/TC4 GTPase cycle.

Base Sequence↗