Biomedical subjects

E Noguchi

Publications and source records attributed to E Noguchi.

At least 73 records · Page 4Linked to original sources

PubMed1996

Increases in gastric acidity in response to electroacupuncture stimulation of the hindlimb of anesthetized rats.

Acupuncture treatment has been used as physiotherapy to treat gastrointestinal disorders in traditional Oriental medicine. In the present study, we selected anesthetized animals as the subjects of this experiment in order to eliminate emotional factors, and investigated the responses to acupuncture stimulation at only a single point by changing animal conditions. 1) There was marked enhancement of gastric acid secretion by electroacupuncture stimulation of the hindlimb based on pH values of the perfusate. However, the enduring response after the momentary initial decrease suggested the existence of humoral factors. 2) The electroacupuncture-specific response was not observed in rats after sciatic nerve denervation. However, the pH values of the perfusate decreased in response to electroacupuncture stimulation of the hindlimb on the sciatic nerve intact side of the same rat. This suggests that the input pathway of acupuncture stimulation was a somatic nerve efferent pathway from the hindlimb. 3) No response to electroacupuncture stimulation was observed in the rats after vagotomy, but a clear enhancement response was seen after sympathectomy. These findings show that the major efferent path of the responses to acupuncture stimulation is the vagus nerve. The results of this experiment suggest that electroacupuncture stimulation of the hindlimb of anesthetized rats increases gastric acid secretion with somatic nerves as the afferent pathway and branches of the vagus nerve to the stomach as the efferent pathway.

Animals↗

PubMed1996

[A new method for measurement of both regional cerebral blood flow and distribution volume using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) and SPECT].

We developed a new method (functional IMP SPECT) to quantitate both regional cerebral blood flow (rCBF) and distribution volume (Vd) using 123I-IMP and SPECT based on a 2- compartment model (influx; K1 =rCBF and outflux; k2). This method requires one arterial blood sampling at 5 min after injection of the tracer and two SPECT scans at 30 min and 60 min. It takes approximately 60 min for total measurements. The integration of arterial input function is estimated by one blood sample taken at 5 min after injection of the tracer without octanol treatment, by using the correlation between one blood sample and the integration, which was obtained from studies on 25 subjects. With the value of integration, K1 and Vd are calculated from the data of two SPECT scans by using the mathematical functions based on the 2-compartment model, which were obtained from studies on 12 subjects. In the practical range of K1 (0.3-0.7 ml/g/min) and Vd (15-35 ml/g) given in the 2-compartment model, statistical errors of K1 and Vd obtained by the functional IMP SPECT were evaluated at approximately 14.0% and 17.2%, respectively. In clinical studies for eight subjects including two healthy volunteers, three patients with cerebral infarction and three patients with degenerative disease, K1 and Vd values estimated by the functional IMP SPECT were significantly correlated with those estimated by non-linear least squares fitting analysis based on the 2-compartment model, and the mean errors of K1 and Vd estimated by the functional IMP SPECT were approximately 8.0% and 11.2% respectively, suggesting the validity of the new method. We conclude that the functional IMP SPECT is clinically useful because of the accuracy, less-invasiveness and convenience.

Amphetamines↗

PubMed1996

[A functional diagnostic method by measuring of distribution volume of 123I-IMP with SPECT].

To measure distribution volume of 123I-IMP with one-point sampling of arterial blood and 2 times SPECT scans using the Magic square method (Rate constant square method), we introduced a program on a SPECT computer system. In this program four functional images; distribution volume, CBF (K1), k2 and delayed/early ratio, and absolute values with S.D. are obtained on the computer. We have been using the program on daily SPECT studies. In this study we discussed the usefulness of the method. Redistribution phenomenon of 123I-IMP, which is not exactly enough investigated, can be transformed into a functional parameter, distribution volume. Since distribution volume represents an extent of retention of 123I-IMP in brain tissue, it can play an important role to evaluate functional activity in the brain and to diagnose cerebral diseases.

Adult↗

PubMed1996

[Validation study in quantitative measurement of regional cerebral blood flow using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) and SPECT].

We validated following five methods to quantitate regional cerebral blood flow (rCBF) using 123I-IMP and SPECT; 1) microsphere method, which is based on a microsphere model using the SPECT image at five minutes after 123I-IMP injection with continuous withdrawal of arterial blood, 2) microsphere+ one-point sampling method, which is the same as the microsphere method except for using one-point sampling instead of continuous withdrawal, 3) conventional microsphere + one-point sampling method, which is the same as the microsphere + one-point sampling method except for using a later SPECT image corrected with the ratio of alteration of measured entire brain activity, 4) Table look-up method, which is based on a two-compartment model (influx; K1 and outflux; k2) using one arterial blood sample taken at 10 min and two SPECT images at 30 min and 180 min post-injection, and 5) functional IMP SPECT, which is based on the two-compartment model using one arterial blood sample taken at 5 min and two SPECT images at 30 min and 60 min post-injection. Those methods were applied to six patients with cerebral infarction and degenerative diseases, and rCBF results were compared with those estimated by non-linear least squares fitting (NLLSF) analysis based on the two-compartment model. The rCBF values obtained by the microsphere method was best correlated with those by NLLSF analysis (r = 0.940), followed by the microsphere+one-point sampling method (r = 0.885) and the functional IMP SPECT (r = 0.882). The table look-up method underestimated rCBF especially at the high flow level, however showed good correlation (r = 0.859). The conventional microsphere + one-point sampling method overestimated rCBF, however showed good correlation (r = 0.849). Distribution volume (Vd = K1/k2) was also estimated by both the table look-up method and the functional IMP SPECT. While values of Vd by the functional IMP SPECT were significantly correlated with those by NLLSF analysis (r = 0.785), the table look-up method overestimated Vd (43.4 +/- 6.6 ml/g) and showed not good correlation (r = 0.287).

Brain↗

PubMed1995

Evaluation of cerebral blood flow in patients with idiopathic orthostatic hypotension using Tc-99m HMPAO brain SPECT during postural testing.

To determine whether regional cerebral blood flow (rCBF) would change on standing in patients with idiopathic orthostatic hypotension (IOH), Tc-99m HMPAO SPECT studies were performed during postural testing in five patients with IOH. After 10 minutes of quiet rest on a bed, the patients arose quickly and, at the same time, the radiotracer was injected intravenously. SPECT data were obtained with a ring-type SPECT scanner. Another dose of Tc-99m HMPAO was injected with the subjects in the supine position, and SPECT was performed again. Image subtraction was used to evaluate the change in rCBF caused by postural testing. In all patients, the authors observed a decrease of rCBF ni the frontal cortex and basal ganglia. This preliminary study suggests that changes in rCBF occur in patients with IOH on standing, and Tc-99m HMPAO SPECT performed during postural testing may have an important role in evaluating these changes.

Brain↗

PubMed1995

[A study on accuracy of rCBF measurements using the conventional microsphere method with N-isopropyl-p-[123I]iodoamphetamine and SPECT].

To evaluate the accuracy of conventional microsphere method for the measurement of regional cerebral blood flow (rCBF) based on the microsphere model with N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) and SPECT, we performed simulation analysis and clinical studies. Although the microsphere method requires early SPECT scan at a few minutes after injection of the tracer for the accurate measurement of rCBF, the conventional microsphere method, which is generally used, requires more delayed SPECT scan with long scan-duration. In the conventional microsphere method, the delayed SPECT image is corrected to the image at a few minutes after injection of the tracer by using the monitored entire brain activity. By the simulation analysis based on the 2-compartment model (influx; K1 and outflux; k2) using the input function and the entire brain activity obtained from eight subjects respectively, it was found that the conventional microsphere method overestimated the rCBF in the practical range of rCBF and Vd (= K1/k2) given in the 2-compartment model. When the values of rCBF and Vd in the 2-compartment model were given at 0.5 (ml/g/min) and 30 (ml/g) respectively, the rate of overestimation of rCBF by the conventional microsphere method was determined to be 17.3 +/- 0.7% (mean +/- S.D.). Also in clinical studies for eight subjects, the conventional microsphere method overestimated the rCBF compared with those evaluated by non-linear least squares fitting (NLLSF) analysis based on the 2-compartment model. Those results agreed well with the simulation analysis, suggesting the validity of the simulation. The rCBF values clinically estimated by the conventional method were, however, significantly correlated with those calculated by NLLSF analysis, and there were not so much difference between the two quantitative rCBF images obtained by the conventional microsphere method and the microsphere method. Therefore, we conclude that the conventional microsphere method is clinically useful in spite of the overestimation of rCBF.

Amphetamines↗

PubMed1994

A novel strategy for stabilization of Escherichia coli ribonuclease HI involving a screen for an intragenic suppressor of carboxyl-terminal deletions.

A strategy to genetically select Escherichia coli ribonuclease HI mutants with enhanced thermostability is described. E. coli strain MIC3001, which shows an RNase H-dependent, temperature-sensitive growth phenotype, was used for this purpose. Introduction of the rnhA gene permits the growth of this temperature-sensitive strain, whereas the gene for the truncated protein, 142-RNase HI, which lacks the carboxyl-terminal 13 residues, cannot. Analyses of the production levels and the stability of a series of mutant proteins with COOH-terminal truncations suggested that 142-RNase HI is nonfunctional in vivo because of a dramatic decrease in the protein stability. Polymerase chain reaction-mediated random mutagenesis of the rnhA142 gene, encoding 142-RNase HI, followed by selection of revertants, allowed us to isolate 11 single amino acid substitutions that render 142-RNase HI functional in vivo. Of them, eight substitutions were shown to enhance the thermal stability of the wild-type RNase HI protein, and of these, six were novel. The genetic selection strategy employed in this experiment was thus shown to be effective for identifying amino acid substitutions that enhance the thermal stability of E. coli RNase HI. Such a strategy would be versatile if a protein of interest could be destabilized by a deletion or a truncation and a conditional-lethal strain were available.

Amino Acid Sequence↗

PubMed1994

The CCG1/TAFII250 gene is mutated in thermosensitive G1 mutants of the BHK21 cell line derived from golden hamster.

The CCG1 cDNA encoding a general transcription factor, TAFII250, complements a thermosensitive (ts) cell cycle mutant, tsBN462, of the BHK21 cell line, which arrests in the G1 phase at the restrictive temperature. In order to clarify whether the CCG1 is mutated in tsBN462 cells or a suppressor of tsBN462 mutation, CCG1 cDNAs isolated from parental wild-type (wt) BHK21 and tsBN462 cell lines were sequenced. Comparison of the nucleotide (nt) sequences showed a single transition: G-->A in the second base of codon 690 of the tsBN462 CCG1 cDNA, resulting in a Gly690-->Asp change. The BHK CCG1 cDNA, but not the tsBN462 CCG1 cDNA, complemented the tsBN462 mutation, proving that the CCG1 is mutated in the tsBN462 cell line. Thus, the defect of general transcription factor, TAFII250, is suggested to cause a G1 arrest in the cell cycle.

Amino Acid Sequence↗

PubMed1994

Investigating the role of conserved residue Asp134 in Escherichia coli ribonuclease HI by site-directed random mutagenesis.

The role of the conserved Asp134 residue in Escherichia coli ribonuclease HI, which is located at the center of the alpha V helix and lies close to the active site, was analyzed by means of site-directed random mutagenesis. Mutant rnhA genes encoding proteins with ribonuclease H activities were screened by their ability to suppress the ribonuclease-H-dependent, temperature-sensitive growth phenotype of E. coli strain MIC3001. Based on the DNA sequences, nine mutant proteins were predicted to have ribonuclease H activity in vivo. All of these mutant proteins were purified to homogeneity and examined for enzymic activity and protein stability. Among them, only the mutant proteins [D134H]RNase H and [D134N]RNase H were shown to have considerable ribonuclease H activities. Determination of the kinetic parameters revealed that replacement of Asp134 by amino acid residues other than asparagine and histidine dramatically decreased the enzymic activity without seriously affecting the substrate binding. Determination of the CD spectra indicated that none of the mutations seriously affected secondary and tertiary structure. The protein stability was determined from the thermal denaturation curves. All mutant proteins were more stable than the wild-type protein. Such stabilization effects would be a result of a reduction in the negative charge repulsion between Asp134 and the active-site residues, and/or an enhancement of the stability of the alpha V helix. These results strongly suggest that Asp134 does not contribute to the maintenance of the molecular architecture but the carboxyl oxygen at its delta 1 position impacts catalysis.

Amino Acid Sequence↗

PubMed1994

Minimum essential region of CCG1/TAFII250 required for complementing the temperature-sensitive cell cycle mutants, tsBN462 and ts13 cells, of hamster BHK21 cells.

CCG1/TAFII250, the largest subunit of the TFIID complex, is mutated in ts cell cycle mutants of BHK21 cells, ts13 and tsBN462, which have a promoter-selective transcriptional defect. A series of deletion mutants of CCG1 cDNA were prepared and transfected into these mutants, in order to identify functional domains of CCG1 required for the complementation of ts 13/BN462 mutation. We determined the minimum size of CCG1:CCG1ME, essential for complementing the ts mutation, which possessed one proline cluster, an HMG1-like domain, and a nuclear localization signal, but which lacked the bromo domains and the acidic phosphorylation sites for casein kinase II common to transcriptional activators. It encodes a protein of 140 kDa. These characteristics of CCG1ME correspond to yeast TAFII145, the yeast homolog of human TAFII250. CCG1ME bound to TBP, creating its own TFIID complex different from that of the endogenous mutated CCG1 in ts+ transformants of tsBN462 cells.

Animals↗

PubMed1994

Effect of chest wall vibration on dyspnea in patients with chronic respiratory disease.

The effect of chest wall vibration on dyspnea at rest was investigated in 15 patients with severe chronic respiratory diseases. The magnitude of their baseline dyspnea was 17.9 +/- SE 3.3 mm on a 150-mm visual analog scale. One hundred hertz out-of-phase vibration (OPV; inspiratory intercostal muscles vibrated during expiration and expiratory intercostal muscles vibrated during inspiration) increased dyspnea an average of 21.9 +/- SE 7.8 mm (p < 0.05). One hundred hertz in-phase vibration (IPV; inspiratory intercostal muscles vibrated during inspiration and expiratory intercostal muscles vibrated during expiration) decreased dyspnea an average of 6.9 +/- SE 2.8 mm (p < 0.05). Changes in the respiratory pattern and arterial blood gas determinations elicited by 5-min IPV were investigated in eight of the 15 patients. Tidal volume was significantly increased in all eight of these patients. Respiratory frequency was decreased in seven patients and increased in one. Functional residual capacity, measured before and during the application of IPV for a period of about 10 breaths, was increased in one patient and decreased in the remaining seven. PaCO2 decreased by 1.3 +/- 1.0 mm Hg (p < 0.05), from 49.6 +/- 8.4 mm Hg; PaO2 increased by 3.4 +/- 2.3 mm Hg (p < 0.05), from 67.7 +/- 12.7 mm Hg. The results indicate that in-phase chest wall vibration decreased pathologic dyspnea in patients with chronic respiratory disease and suggest that the effects on respiratory sensation are mediated by afferent information from chest wall respiratory muscles to supraspinal centers.

Aged↗

PubMed1994

[Quantifying regional cerebral blood flow with N-isopropyl-p-[123I]iodoamphetamine and SPECT by one-point sampling method].

We developed a new non-invasive technique; one-point sampling method, for quantitative measurement of regional cerebral blood flow (rCBF) with N-isopropyl-p-[123I]iodoamphetamine and SPECT. Although the continuous withdrawal of arterial blood and octanol treatment of the blood are required in the conventional microsphere method, the new technique does not require these two procedures. The total activity of 123I-IMP obtained by the continuous withdrawal of arterial blood is inferred by the activity of 123I-IMP obtained by the one point arterial sample using a regression line. To determine when one point sampling time was optimum for inferring integral input function of the continuous withdrawal and whether the treatment of sampled blood for octanol fraction was required, we examined a correlation between the total activity of arterial blood withdrawn from 0 to 5 min after the injection and the activity of one point sample obtained at time t, and calculated a regression line. As the results, the minimum % error for the inference using the regression line was obtained at 6 min after the 123I-IMP injection, moreover, the octanol treatment was not required. Then examining an effect on the values of rCBF when the sampling time was deviated from 6 min, we could correct the values in approximately 3% error when the sample was obtained at 6 +/- 1 min after the injection. The one-point sampling method provides accurate and relatively non-invasive measurement of rCBF without octanol extraction of arterial blood.

Adolescent↗

PubMed1994

[A study on evaluation of CBF measurement based on microsphere model with N-isopropyl-p-[123I]iodoamphetamine (IMP) and SPECT--its correction with the value of PaCO2].

To evaluate the regional cerebral blood flow measurement with N-isopropyl-p-[123I]iodoamphetamine (IMP), we performed 123I-IMP SPECT and 133Xe inhalation method on 9 patients with mild cerebrovascular diseases and so on. A tracer dose of 123I-IMP (111 MBq) was injected i.v. and the data were obtained 15 min later. Regional CBF was measured by the microsphere model and arterial blood sampling method. However, mean cerebral blood flow values was not in agreement with both methods. We supposed the reason of the disagreement was due to the difference of PaCO2 when the studies were performed. Hence, CBF measurement with 123I-IMP was performed on the other patient's population with loading of hyperventilation before the IMP injection. Comparing with the control state with normal breathing, we calculated the rate of change of mean CBF between the state with normal breathing and the state with hyperventilation that was 1.02 ml/100 g/min/mmHg PaCO2. After the correction with the rate, we observed a much significant relation between the mean CBF measured with 123I-IMP SPECT and 133Xe inhalation method. When compared CBF values with loading studies or certain therapies, the correction of CBF with the rate of change of PaCO2 is one of the very important factors to be considered. Moreover, 133Xe inhalation method without the correction of PaCO2 can not be a golden standard method for rCBF measurement.

Adult↗

PubMed1994

[A problem of quantitative measurement of regional cerebral blood flow using microsphere model and N-isopropyl-p-[123I]iodoamphetamine (IMP): comparison with 133Xe SPECT and sequential dynamic 123I-IMP SPECT].

Regional cerebral blood flow (rCBF) was measured in 13 patients with various cerebral disease by N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT with the microsphere model (rCBF (CbST)), which was compared with 133Xe inhalation SPECT (rCBFXe). Continuous withdrawal of arterial blood was performed for 5 minutes and SPECT image was obtained from 25 min to 55 min after the tracer injection. The reconstructed counts at 5 min was corrected using entire cerebral counts collected at 5 min, 20 min, and 60 min after the tracer injection. As compared with rCBFXe, rCBF (CbST) was underestimated in high flow areas and overestimated in low flow areas. Regional CBF was also measured using one minute short time SPECT images at 5 min (rCBF (Cb5)), 20 min (rCBF (Cb20)), and 60 min (rCBF (Cb60)) after the injection. Regional CBF tended to be underestimated with time from the tracer injection due to the wash-out from brain tissue to blood. In comparison with rCBF (Cb5), rCBF (CbST) was underestimated in high flow areas and overestimated in low flow areas. This error was considered to be due to the correction of reconstruct counts using entire cerebral counts, because of the kinetic behavior of 123I-IMP was different in each region of the brain.

Adult↗

PubMed1993

Molecular cloning and identification of two types of hamster cyclin-dependent kinases: cdk2 and cdk2L.

We isolated two types of hamster cyclin-dependent kinase 2 (cdk2) cDNAs from BHK21 cells derived from Golden hamsters. One type of cdk2 (cdk2hm) encodes the 32 kDa protein consisting of 298 predicted amino acids and shows strong homology to the cdk2 cDNAs of humans and Xenopus. The other cdk2 (cdk2Lhm) encodes the 38 kDa protein containing the insertion of 48 amino acids in the cdk2hm protein. Immunoblotting analysis suggested that these two types of cdk2 protein exist in mammalian cells. The cdk2hm has the activity of protein kinase, while the cdk2Lhm does not, however, both bind with cyclin E.

3T3 Cells↗

PubMed1993

Skin permeation enhancement of tegafur by ethanol/panasate 800 or ethanol/water binary vehicle and combined effect of fatty acids and fatty alcohols.

The effects of vehicle and enhancer on the skin permeation of tegafur across excised hairless mouse skin were investigated. Ethanol, water, panasate 800 (tricaprylin), and their mixtures were used as vehicles, and then a series of fatty acids or fatty alcohols was employed as representative enhancers. The skin permeability of tegafur was dramatically increased by the combination of ethanol and panasate 800, whereas the combination of ethanol and water resulted in only a little increase. The greatest permeation ratio (56.8% of dose at 12 h) was obtained with the ethanol/panasate 800 (40/60) binary vehicle. Furthermore, the skin permeability of tegafur could be enhanced by the addition of fatty acids or fatty alcohols to ethanol/panasate 800 (40/60) and ethanol/water (60/40) binary vehicles. The infinite dose studies suggested that panasate 800 decreased the lag time by increasing the diffusion of tegafur, and ethanol increased the permeation rate by increasing the partition of tegafur into skin. The effects of fatty acids or fatty alcohols added to ethanol as a single vehicle were dramatic, but did not appear in the case of panasate 800 as a single vehicle. In conclusion, panasate 800 was an excellent hydrophobic vehicle in that it minimized time lag and promoted tegafur permeability combined with ethanol. This improvement was further promoted when enhancers were added.

Animals↗

PubMed1993

[A new graphic method for evaluation of distribution volume on N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT].

We developed a new graphic method using N-isopropyl-p-[123I]iodoamphetamine (IMP) and SPECT of the brain, the graph on which all three parameters, cerebral blood flow, distribution volume (Vd) and delayed count to early count ratio (Delayed/Early ratio), were able to be evaluated simultaneously. The kinetics of 123I-IMP in the brain was analyzed by a 2-compartment model, and a standard input function was prepared by averaging the time activity curves of 123I-IMP in arterial blood on 6 patients with small cerebral infarction etc. including 2 normal controls. Being applied this method to the differential diagnosis between Parkinson's disease and progressive supranuclear palsy, we were able to differentiate both with a glance, because the distribution volume of the frontal lobe significantly decreased in Parkinson's disease (Mean +/- SD; 26 +/- 6 ml/g). This method was clinically useful. We think that the distribution volume of 123I-IMP may reflect its retention mechanism in the brain, and the values are related to amine, especially to dopamine receptors and its metabolism.

Aged↗

PubMed1993

[A study of crossed cerebellar diaschisis on 123I-IMP SPECT images and its redistribution phenomenon].

Crossed cerebellar diaschisis (CCD) is interpreted as a functional deactivation, presumably caused by a loss of excitatory or inhibitory afferent inputs on the corticopontocerebellar pathway and others. A redistribution phenomenon (RD) is usually observed in the contralateral cerebellum with CCD on delayed images of 123I-IMP SPECT. This phenomenon was analyzed in a view point of rCBF measurement in 24 patients with brain tumor, infarction and so forth. Regional CBF was measured by the microsphere method with 123I-IMP and a delayed-to-early counts ratio (D/E ratio) was used. As a result, there was no relation between rCBF and the D/E ratio in the cerebellum, which means that RD is occurred by other factors except for rCBF in the cerebellum. Regional CBF and the D/E ratio in the contralateral and ipsilateral cerebellum was 46.3 ml/100 g/min, 1.01 and 57.0 ml/100 g/min, 0.86, respectively. These results mean that the high activity of IMP gradually decreased in the ipsilateral cerebellum, while, the low activity in the contralateral cerebellum was almost stable, and the difference of both activity reduced after 5 hours and RD was observed on the delayed image. The data indicate that retention mechanism of IMP and vascular permeability are not affected in the cerebellum with CCD.

Adolescent↗