Biomedical subjects

T Tsuchiya

Publications and source records attributed to T Tsuchiya.

At least 469 records · Page 26Linked to original sources

PubMed1991

Change of accumulation and filling pattern in evolution of cerebral infarction with I-123 IMP brain SPECT.

Twenty-eight patients with cerebral infarction were examined by brain SPECT with I-123 IMP a total of 46 times from Day 2 to Day 84 after the onset of stroke. Depending on the pattern of change in the abnormal accumulation of I-123 IMP between the early and delayed images, the patients were classified into one of five types. The number of patients in each type and the number of days after infarction at which each type occurred were as follows: Type (I), n = 5 and 4 +/- 2 days; Type (II), n = 8 and 12 +/- 4 days; Type (III), n = 17 and 21 +/- 11 days; Type (IV), n = 13 and 38 +/- 18 days; and Type (V), n = 3 and 60 +/- 16 days. In 12 patients, 30 brain SPECT were performed that showed the chronological evolution of infarction in sequence from Types (I) to (IV). Hyperactivity in the early image was seen in Type (I) with a subsequent image defect, while in Type (II) there was persistent hyperactivity. Hypoactivity in the early image was seen in Types (III), (IV), and (V), and the activity in the delayed image gradually decreased as the process of infarction terminated. The early image reflected the distribution of lipophilic I-123 IMP, indicating regional cerebral blood flow, while the delayed image showed the distribution of hydrophilic I-123 IMP metabolites superimposed on that of lipophilic I-123 IMP which had accumulated in the brain at the first extraction. Combining the early and delayed images of I-123 IMP brain SPECT may help to understand the evolution of cerebral infarction.

Adult↗

PubMed1991

Embryolethality of new herbicides is not detected by the micromass teratogen tests.

New herbicidal compounds (11 pyrimidine-diones, 3 benzoates and 1 sulfonamide) were found to be embryolethal but not teratogenic in rats. The range of the embryolethal dose varied from 0.2 to greater than 200 mg/kg. This broad range enabled us to validate whether proposed in vitro teratogen tests can detect the embryolethality of these herbicides. The IC50 values (inhibition concentration 50%) for both differentiation and proliferation of midbrain and limb bud cells of rat embryos were determined and found to be above 50 micrograms/ml in all cases, confirming that the herbicides were not teratogenic. No correlation, however, was observed between the embryolethality in vivo and the activities in these cells. In order to test whether the potential to cause embryolethality could be predicted and detected as a general cytotoxic effect, the inhibition of colony forming ability in V79 cells was determined. The results indicated that cytotoxicity in V79 cells may be useful for preliminary testing of the embryolethal effect of herbicides.

Abnormalities, Drug-Induced↗

PubMed1991

Effects of olfactory stimulation on the sleep time induced by pentobarbital administration in mice.

The effect on the pentobarbital sleep time by olfactory stimulation with various odorants was investigated using mice to appraise the physiological or psychological significance of olfactory information. The sleep time was determined as the time elapsed between intraperitoneal pentobarbital administration and the first time that the animal was able to spontaneously right itself. The sleep time was affected by inhalation of some odorants compared to pure air controls, but not by others. The sleep time was prolonged by terpinyl acetate and phenethyl alcohol, and was shortened by lemon oil and jasmin oil. However, neither potentiation nor attenuation of pentobarbital action by odorant inhalation was observed when using anosmic mice produced by intranasal zinc sulphate treatment. In conclusion, olfactory stimulation associated with odorant inhalation influences the pentobarbital sleep time, suggesting that olfactory information may have a more potent influence on the physiological and psychological status than has previously been thought.

Animals↗

PubMed1991

Eosinophilia caused by administration of L-tryptophan to animals with adrenal dysfunction.

We have investigated an animal model of eosinophilia-myalgia syndrome (EMS), a disease that occurred in various parts of the United States in 1989, with a view to determining its cause. We speculated that adrenal dysfunction might have potentially contributed to the occurrence of EMS and studied the effects of adrenal dysfunction on the eosinophil count in peripheral blood by using rats and mice whose adrenals had been excised or that had been metyrapone-treated, and giving them L-tryptophan. As a result, a significant increase in the eosinophil count was observed in both animal species. The results suggest that EMS may have been caused, not by L-tryptophan alone, but by the combined effects of adrenal dysfunction and L-tryptophan ingestion.

Administration, Oral↗

PubMed1991

Sequence analysis of nutA gene encoding membrane-bound Cl(-)-dependent 5'-nucleotidase of Vibrio parahaemolyticus.

The membrane-bound 5'-nucleotidase of Vibrio parahaemolyticus is unique in requiring Cl- for activity. We cloned the nutA gene encoding the 5'-nucleotidase and sequenced it. It contained an open reading frame consisting of 1,680 nucleotides capable of encoding a protein of 560 amino acid residues. The first 21 amino acid residues of the N-terminal portion of this protein seem to be a signal peptide. The rest of the polypeptide (539 residues) is hydrophilic, and its molecular weight was calculated to be 60,008, which is in good agreement with the value of 63 kDa determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the 5'-nucleotidase derived from the cloned nutA gene. We tried to determine the amino acid sequence of the N-terminal portion of the purified enzyme. However, the N-terminal residue seemed to be blocked. As this 5'-nucleotidase can be solubilized from membrane vesicles with detergent, it may be a lipoprotein. The amino acid sequence around the possible cleavage site of the 5'-nucleotidase had homology with the sequences of the cleavage sites of the lipoproteins of Escherichia coli and other bacteria. The amino acid sequence had high (about 60%) homology with the sequence of periplasmic 5'-nucleotidase (uridine diphosphate sugar hydrolase, the product of the ushA gene) of E. coli. It also contained regions that showed some homology with the nucleotide binding sites of many nucleotide binding proteins.

5'-Nucleotidase↗

PubMed1991

A specific glutathione S-transferase isozyme occurring in hereditary hyperbilirubinuria rats.

A glutathione S-transferase isozyme which is absent in normal rat liver has been isolated from the hereditary hyperbilirubinuria rat liver cytosol. The enzyme was purified to apparent homogeneity by GSH-affinity chromatography and HPLC on CM-Sepharose CL-6B. It is a heterodimer of two non-identical subunits, i.e., subunit 2 and a previously uncharacterized subunit referred to here as subunit Yx. Immunoblot analysis indicated that GST 2-Yx belongs to the alpha class. GST 2-Yx is characterized by its 4-fold higher activity towards 4-hydroxy-non-2-enal, compared to that of GST 2-2.

Animals↗

PubMed1991

Inhibition of homoserine dehydrogenase I by L-serine in Escherichia coli.

We have reported that a major cause of growth inhibition of Escherichia coli by L-serine is its inhibition of homoserine dehydrogenase I (HDH I), which is involved in the biosyntheses of threonine and isoleucine [Hama, H., Sumita, Y., Kakutani, Y., Tsuda, M., & Tsuchiya, T. (1990) Biochem. Biophys. Res. Commun. 168, 1211-1216]. However, Patte et al. reported that L-serine does not inhibit HDH I [Patte, J.-C., Truffa-Bachi, P., & Cohen, G.N. (1966) Biochim. Biophys. Acta 128, 426-439]. In studies on the reason for these discrepant results, we found that the concentration of K+ and the pH in the assay mixture strongly influenced the inhibitory effect of L-serine. L-Serine strongly inhibited the HDH I activities in both the forward and reverse reactions between aspartate semialdehyde and homoserine at a physiological K+ concentration (100 to 200 mM) and physiological pH (7.5) for E. coli cells. On the other hand, two well-known inhibitors of HDH I, L-threonine and L-cysteine, strongly inhibited the activity regardless of the K+ concentration and pH.

Cations, Monovalent↗

PubMed1991

Cloning and nucleotide sequence of the gene (citA) encoding a citrate carrier from Salmonella typhimurium.

A cryptic citrate transport gene (citA) from Salmonella typhimurium chromosome was cloned and its nucleotide sequence was determined. The cloned plasmid conferred citrate-utilizing ability on wild-type Escherichia coli, which cannot grow on citrate as the sole source of carbon. The resultant E. coli transformant was able to transport citrate. A 1,302-base-pair open reading frame with a preceding ribosomal binding site was found in the cloned DNA fragment. The 434-amino-acid protein that could be translated from this open reading frame is highly hydrophobic (69% nonpolar amino acid residues), consistent with the fact that the transport protein is an intrinsic membrane protein. The molecular weight of this protein was calculated to be 47,188. The gene sequence determined is highly homologous to those of Cit+ plasmid-mediated citrate transport gene, citA, from E. coli, the chromosomal citA gene from Citrobacter amalonaticus and the chromosomal cit+ gene from Klebsiella pneumoniae. The hydropathy profile of the deduced amino acid sequence suggests that this carrier has 12 hydrophobic segments, which may span the membrane lipid bilayer.

Amino Acid Sequence↗

PubMed1991

Endothelium-derived nitric oxide as a mediator of acetylcholine-induced coronary vasodilation in dogs.

To investigate the role of endothelium-derived nitric oxide (NO) in regulation of the tonus of the coronary artery system in vivo, the effect of NG-mono-methyl-L-arginine (L-NMMA), a specific inhibitor of the synthesis of NO from L-arginine, on acetylcholine (ACh)-induced coronary vasodilation was examined in open-chest, anesthetized dogs. At baseline, the infusion of ACh and adenosine into the left circumflex coronary artery (LCX) increased the LCX blood flow. Continuous infusion of L-NMMA (2 mumol/min, for 20 min) into LCX significantly attenuated ACh-induced increase in the LCX flow: percentage increases in the LCX flow by ACh (10 and 100 ng/kg) before L-NMMA were 42.0 +/- 8.7 and 137.3 +/- 12.5%, respectively, whereas those after L-NMMA were 14.0 +/- 4.9 (p less than 0.02) and 88.9 +/- 10.9% (p less than 0.005), respectively. L-NMMA showed no effect on adenosine-induced increase in the LCX flow. After the L-NMMA infusion was terminated, the effect of ACh partially returned to the baseline level. In other dogs, L-arginine (3 mg/min, for 20 min) was administered just after the L-NMMA infusion, which completely reversed the inhibitory effect of L-NMMA on ACh-induced vasodilation. Endothelium-derived NO is a mediator of ACh-induced vasodilation of the coronary resistance vessels in dogs.

Acetylcholine↗

PubMed1991

Characterization and mapping of a major Na+/H+ antiporter gene of Escherichia coli.

Using in vivo assays, we show that the Na+/H+ antiporter activity of the Escherichia coli mutant HIT-1 is reduced dramatically compared with activity in wild-type cells. An isogenic nhaA (formerly antA) deletion strain, however, is not significantly different from wild type in this respect. We call the locus affecting Na+/H+ antiporter activity of the HIT-1 mutant nhaB. The nhaB activity exhibits no pH dependence in the range between 7.0 and 8.5, whereas that of the nhaA gene increases considerably at pH levels above 8.0. Mutants with defects in nhaB grow normally on agar media containing 0.5 M NaCl, but nhaA mutants are sensitive to 0.5 M NaCl. We have mapped the nhaB mutation of HIT-1 to 25.6 min on the E. coli map. It is unlinked to the nhaA region, which is located at about 0.5 min. Since a cell with a mutation in nhaB alone is essentially Na+/H+ antiporter negative up to pH 8.0, we conclude that nhaB is required for the major Na+/H+ antiporter activity in the usual physiological pH range.

Carrier Proteins↗

PubMed1991

Effect of partial Na pump and Na-H exchange inhibition on [Ca]i during acidosis in cardiac cells.

This study investigated the effects of partial Na pump inhibition and Na-H exchange inhibition on contractile function, intracellular pH (pHi), and intracellular Ca concentration ([Ca]i) during intracellular acidosis, using the fluorescent dyes 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein and fura-2 in isolated cardiac cells of adult rabbits. Intracellular acidosis with normal extracellular pH was induced by an NH4Cl (10 mM) prepulse technique. A nontoxic concentration (0.5 microM) of ouabain was used to inhibit the Na pump. 5-(N-ethyl-N-isopropyl)amiloride (EIPA) was used to inhibit Na-H exchange. In both the absence and presence of ouabain, pHi fell transiently and then recovered after removal of NH4Cl. Ouabain did not alter the pHi changes observed after removal of NH4Cl. Diastolic and systolic [Ca]i increased during acidosis after NH4Cl removal. In the presence of ouabain, the increase in [Ca]i during acidosis was greater than that in the absence of this drug. Ouabain enhanced the recovery of contractile function during acidosis. In both the absence and presence of ouabain, Na-H exchange inhibition by EIPA reduced the recovery of pHi and mechanical function and the increase in [Ca]i, which were normally observed after NH4Cl removal. These data suggest that in adult rabbit myocytes the Na pump inhibition enhances the increase in [Ca]i during acidosis, and the Na-H exchange inhibition reduces it. The [Ca]i increase during acidosis may be in part due to the altered Na-Ca exchange, which in turn results from the increased Na-H exchange.

Acidosis↗

PubMed1991

Formycin A resistant mutants due to defect in adenosine transport system in Vibrio parahaemolyticus.

An antibiotic formycin A inhibited growth of Vibrio parahaemolyticus under certain conditions, which suggested that formycin A was taken up by cells under these conditions. We found that formycin A was transported via the adenosine transport system which we previously reported as a Na(+)-coupled cotransport system. We isolated many formycin A resistant mutants, and about half of them grew very poorly on adenosine as a sole source of carbon. Judging from their reversion frequencies, these mutants seemed to have single mutations. Respiration driven uptake of 14C-adenosine was not observed in such mutants; also, Na+ uptake induced by the addition of adenosine or formycin A to a cell suspension was completely abolished in them. Thus we conclude that these mutants possess a defect in the Na+/adenosine cotransport system, and have become formycin A resistant.

Adenosine↗

PubMed1991

Ultrasonography in transient synovitis and early Perthes' disease.

We used ultrasonography to examine 36 children suffering from transient synovitis and 12 children with early Perthes' disease. Widening of the joint space was revealed by ultrasonography in all affected hips with either disease. In the patients with transient synovitis, capsular distension was attributed to synovial effusion, while in the patients with Perthes' disease it was produced by thickening of the synovial membrane. Neither capsular distension nor thickening of the joint cartilage was seen in the contralateral normal hip in the patients with transient synovitis, but they were common in early Perthes' disease. Ultrasonography may provide significant diagnostic clues to differentiate early Perthes' from transient synovitis.

Child↗

PubMed1991

Ultrasonography in congenital dislocation of the hip. Simultaneous imaging of both hips from in front.

We describe a new technique for examining the infant hip using ultrasound. Both hips are imaged simultaneously via an anterior approach. The examination can be done with the hip either extended or flexed and abducted. The method has three advantages: 1) since both hips are imaged simultaneously, lines can be drawn to assist in determining the relationship between the femoral head and the pelvis; 2) proximal, anteroposterior and lateral displacement of the femoral head can all be demonstrated; 3) the method is applicable to the infant in a harness or a plaster cast to demonstrate maintenance of reduction of a dislocated hip. The usual direction of dislocation of the femoral head was anterior and lateral. Proximal migration was also observed in cases with more severe dislocation. In flexion, the dislocated head of the femur often moved posterior to the acetabulum. Of 1276 hips, in 638 infants aged from three weeks to one year, 49 showed congenital dislocation. The accuracy of our anterior method of sonography in diagnosing congenital dislocation of the hip compared well with the method of Graf and with radiography.

Female↗

PubMed1991

Improvement of postoperative hypocalcemia by repeated allotransplantation of parathyroid tissue without anti-rejection therapy.

Long lasting postoperative hypocalcemia, an uncomfortable complication of a thyroid operation for hyperthyroidism, was treated with allotransplantation of parathyroid tissue. Small pieces of the parathyroid tissue offered from two unrelated donors were transplanted to an 18-year-old male with severe postoperative hypoparathyroidism. Prednisolone was given for 2 days, but no other immunosuppressive drugs were used. The remaining tissue was stored in frozen for the repeat transplantation. The functional activity of the frozen tissue was determined by the production of parathyroid hormone in the tissue culture medium adjusted to appropriate concentration of calcium. Loss of the graft function, probably due to rejection, was supplemented with repeated grafting. Hypocalcemia was improved by three times of transplantation using frozen tissue (once) and fresh tissue (twice). This preliminary trial demonstrates that the tissue transplantation of the parathyroid gland is effective to lessen the symptoms and medication of postoperative hypoparathyroidism.

Adolescent↗

PubMed1991

Somatic afferent regulation of plasma corticosterone in anesthetized rats.

Effects of cutaneous stimulation on plasma corticosterone were examined in adult male Wistar rats anesthetized with pentobarbital. Under the resting condition, plasma corticosterone measured every 15 min between 1430 and 1630 h revealed no significant circadian fluctuations. Nociceptive mechanical stimulation of bilateral hindpaws by pinching for 10 min significantly increased plasma corticosterone for the following 1 h, whereas innocuous mechanical stimulation of bilateral hindlimbs by brushing for 10 min produced no significant change in plasma corticosterone. These results indicate that somatic sensory information from skin can influence secretion of corticosterone from the adrenal cortex after emotional factors are eliminated by anesthetizing the subjects.

Adrenal Cortex↗

PubMed1991

[Hemodynamics of the vertebral artery in subclavian steal syndrome and subclavian steal phenomenon].

To evaluate hemodynamics of the vertebral artery (VA) in subclavian steal syndrome (SSS) and subclavian steal phenomenon (SSP), blood flow velocities of the bilateral VAs were measured by duplex ultrasonography in four patients with SSS and eight patients with SSP. The reversal of flow in the VA was noted in both systolic and diastolic phases in all of the SSS group, and was recorded only in a systolic phase in all but one of the SSP group. The antegrade mean flow velocities in the VA on the unaffected side in the SSS group were significantly higher than those in the SSP group. This indicates that collateral blood flow through the VA in the SSS group is still insufficient to compensate the blood requirement of the upper extremity on the affected side. In conclusion, hemodynamics of the VA in the SSS group could be distinguished from those in the SSP group by duplex ultrasonography.

Adult↗

PubMed1991

[Post-operative respiratory management of patients with ventricular septal defect with pulmonary hypertension (VSD+PH)].

Post-operative respiratory management was evaluated in patients with VSD+PH. Comparison was made between Group I (6 patients under 6 months) and Group II (10 patients 6 months or above). Oxygenation after surgical operation in Gp I was poor and the patients needed longer period of mechanical ventilation (MV), while Gp II patients required shorter duration of MV. In Gp I, the duration of MV after the cardiac surgery correlated with the length of cardiopulmonary bypass. In conclusion, cardiopulmonary bypass may influence the post-operative pulmonary function and patients who require longer period of MV are younger infants or newborns whose pulmonary function is immature and PH is severe.

Age Factors↗