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T Ohta

Publications and source records attributed to T Ohta.

At least 649 records · Page 36Linked to original sources
PubMed1995

Molecular cloning of the genes for pyruvate kinase of two bacilli, Bacillus psychrophilus and Bacillus licheniformis, and comparison of the properties of the enzymes produced in Escherichia coli.

The genes for the pyruvate kinases of a psychrophile, Bacillus psychrophilus, and a mesophile, Bacillus licheniformis, have been cloned in Escherichia coli, and all their nucleotides were sequenced. The two bacterial enzymes each had an extra C-terminal sequence consisting of about 110 amino acid residues, which has been found in the B. stearothermophilus enzyme. Both enzymes were overexpressed in E. coli and the properties of the purified enzymes were compared to those of the B. stearothermophilus enzyme. Both enzymes were less stable than the B. stearothermophilus one. The B. psychrophilus enzyme was more stable than the B. licheniformis one. Similarly to the B. licheniformis and B. stearothermophilus pyruvate kinases, the B. psychrophilus enzyme was activated by AMP or ribose 5-phosphate, and inhibited by ATP or fructose 1,6-bisphosphate. Thus, these enzymes were very similar in the sigmoidal saturation curve for phosphoenolpyruvate and allosteric effectors, but their optimum temperatures and thermostabilities were very different.

Amino Acid Sequence↗
PubMed1995

Reddish Escherichia coli cells caused by overproduction of Bacillus stearothermophilus uroporphyrinogen III methylase: cloning, sequencing, and expression of the gene.

During shotgun cloning of an amylase gene, we found a transformant of Escherichia coli with a reddish color. The transformant produced highly water-soluble red pigments the molecular masses of which were less than 3000. The plasmid harbored by the transformant contained a DNA fragment derived from a strain of Bacillus stearothermophilus. Truncation of the insert DNA showed that an 1.1-kbp Sau 3A-SalI fragment was responsible for the reddish colony. An open reading frame was found in the nucleotide sequence of the 1.1-kbp DNA fragment. The production of the red pigment was accompanied by a colorless 28-kDa protein. The sequence of the 28-kDa protein was highly homologous to bacterial uroporphyrinogen III methylases participating in corrinoid biosynthesis. The 28-kDa protein was found to be a thermostable uroporphyrinogen III methylase.

Amino Acid Sequence↗
PubMed1995

Role of histidine 188 in fructose 1,6-bisphosphate- and divalent cation-regulated L-lactate dehydrogenase of Lactobacillus casei.

A fructose 1,6-bisphosphate [Fru(1,6)P2] and divalent cation-regulated allosteric L-lactate dehydrogenase (L-LDH) (EC 1.1.1.27) of Lactobacillus casei was highly produced in Escherichia coli cells, together with its mutant enzyme, in which His-188 was replaced by Asp. Under acidic conditions, the mutant enzyme showed positive allosteric regulations by the substrate pyruvate and its analogues, like the wild-type enzyme, but not by Fru(1,6)P2, which even inhibited the stimulative effects of the alternative activation factors. In addition, Mn2+ ions also showed greatly reduced inhibitory effects on the mutant enzyme. Under neutral conditions, on the other hand, the reaction of the mutant enzyme was slightly enhanced by Fru(1,6)P2, but not further stimulated by additional Mn2+ ions, unlike the case of the wild-type enzyme. These results indicate that His-188 is, though not essential for the regulation by the alternative factors, essential for the cooperative regulation by Fru(1,6)P2 and divalent cations in L. casei L-LDH.

Amino Acids↗
PubMed1995

Nucleotide sequence of the FAD synthetase gene from Corynebacterium ammoniagenes and its expression in Escherichia coli.

The nucleotides of a bifunctional enzyme FAD synthetase gene, which showed both flavokinase and ATP:FMN adenylyltransferase activities, from Corynebacterium ammoniagenes were sequenced. The FAD synthetase gene product consisted of 338 amino acids and had a calculated molecular weight of 37,712. The deduced protein sequence of the FAD synthetase shared a homology with those of the protein X of Escherichia coli, which has been reported to have both flavokinase and ATP:FMN adenylyltransferase activities like the FAD synthetase of C. ammoniagenes, and the protein X of Pseudomonas fluorescens. From the analysis of the flanking sequences of the FAD synthetase gene, the gene organization and the operon structure around the FAD synthetase gene of C. ammoniagenes were thought to be different from those of Gram-negative bacteria. An over-expression system of the FAD synthetase of C. ammoniagenes was constructed in E. coli to study the structure and function of the protein. Under the tandem tryptophan promoter, the FAD synthetase activity increased 2231 times compared to that of non-transformed C. ammoniagenes.

Amino Acid Sequence↗
PubMed1995

Muscarinic receptor subtypes mediating catecholamine secretion and increase in intracellular Ca2+ concentration in adrenal chromaffin cells of the guinea pig.

Muscarinic receptor subtypes mediating catecholamine secretion and increase in the intracellular concentration of Ca2+ ([Ca2+]i) were examined using muscarinic agonists and antagonists in dispersed adrenal chromaffin cells of the guinea pig. All muscarinic agonists (1-1,000 microM) tested caused increases in adrenaline secretion in a dose-dependent manner. Muscarine and methacholine were more effective than bethanechol, oxotremorine and pilocarpine. Muscarine and oxotremorine caused a small increase in adrenaline secretion even in the absence of extracellular Ca2+. Both 4-DAMP (0.1 microM) and pirenzepine (0.1 microM), but not methoctramine (0.1 microM), shifted the dose-response curve for muscarine-induced adrenaline secretion to the right. These muscarinic agonists also caused increase in [Ca2+]i in the presence of extracellular Ca2+. Muscarine-induced [Ca2+]i rises were reduced, but not abolished, by removal of extracellular Ca2+. These results suggest that catecholamine secretion induced by muscarinic agonists is mediated through M1, or M1 and M3 muscarinic receptor subtypes in adrenal chromaffin cells of the guinea pig.

Adrenal Medulla↗
PubMed1995

Estimation of bone mineral density and bone loss by means of bone metabolic markers in postmenopausal women.

We have examined healthy women (51 premenopausal women and 30 postmenopausal women; age 28-59) for lumbar bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) and assessed metabolic bone markers, such as type I procollagen carboxy-terminal propeptide (P1CP), pyridinoline (PYR), deoxypyridinoline (DPYR), osteocalcin (BGP) and alkaline phosphatase (ALP). BMD was assessed once a year in three consecutive years. Correlations among the BMD, BMD changes and levels of bone markers in samples at the first DXA assessment were studied. In pre-menopausal women, none of the biochemical markers were correlated with the BMD or changes in BMD. In contrast, BMD in post-menopausal women correlated (negatively) well with levels of P1CP, DPYR, PYR and ALP declining in this order, and a significant positive correlation was observed between the rate of bone loss in postmenopausal women and the P1CP concentration. PYR and DPYR also had a tendency to correlate. Combinations of several bone markers improved the correlation. These results show that by measuring several bone specific biochemical markers in postmenopausal women, one can estimate their rates of bone loss as well as their present BMDs. The measurement of biochemical bone markers will therefore be very useful in evaluating bone status and would be applicable in screening postmenopausal osteopenia.

Adult↗
PubMed1995

Basal tail skin temperature elevation and augmented response to calcitonin gene-related peptide in ovariectomized rats.

Hyper-release of calcitonin gene-related peptide (CGRP) plays a direct and pivotal role in the induction of menopausal hot flushes (HFs), in which a drastic increase in skin temperature occurs. However, it is not possible to investigate whether CGRP induces skin temperature increase and whether skin temperature response to CGRP changes and contributes to the occurrence of HFs in postmenopausal women who are in oestrogen deficiency. By using rats' tail skin temperature (TST), a good marker to evaluate skin temperature regulation, we examined the effects of CGRP and calcitonin (3, 10 and 30 micrograms/kg, i.v.) on TST in female rats and further investigated the TST change induced by CGRP (10 micrograms/kg, i.v.) in ovariectomized (OVX) rats compared with that in sham-operated (Sham) rats. We found that CGRP, but not calcitonin, induced a TST increase in a dose-dependent manner and that the TST change induced by CGRP (0.6 +/- 0.2 degrees C for OVX rats vs 0.3 +/- 0.1 degree C for Sham rats, P < 0.05) and also the basal TST (26.0 +/- 0.2 degrees C for OVX rats vs 25.5 +/- 0.1 degree C for Sham rats) were significantly greater in OVX rats (P < 0.05). Furthermore, treatment with oestradiol (30 micrograms/kg, s.c.) for 8 days partially inhibited the augmented TST response to CGRP in OVX rats and almost completely inhibited (P < 0.05) the basal TST elevation, with the concomitant recovery of the serum oestradiol level to that in Sham rats. These results suggest that the augmented skin temperature response to CGRP and the elevation of basal skin temperature that are found in OVX rats, animals which are oestradiol deficient, may also occur in menopausal women and contribute to their HFs.

Animals↗
PubMed1995

Significance of urinalysis for subsequent kidney and urinary tract disorders in mass screening of adults.

To evaluate dipstick urinalysis as a predictor of subsequent kidney and urinary tract disorders in apparently healthy adults, we designed a cross-sectional, prospective, and retrospective study within a cohort. The severity of proteinuria was significantly (p < 0.01) associated with the amount of pathological casts, whereas hematuria without proteinuria was not. The frequency of subsequent serum creatinine increase (0.3 mg/dl/5 years or more) was significantly enhanced (from 0.4% to 7.3% along with the severity of proteinuria, whereas it was not related to the severity of hematuria. Patients who subsequently developed renal failure and glomerulonephritis exhibited hematuria (11.1-32.1%) less frequent than proteinuria (62.3-83.3%). Even those with renal tumors or stones showed infrequent (14.3-27.9%) hematuria. Thus, urine protein and occult blood have different implications in mass screening.

Adult↗
PubMed1995

[Evaluation of early colorectal cancer with submucosal invasion based on histological architecture].

To clarify the clinicopathological features of tumors with submucosal invasion, especially superficial elevated and sessile ones, histological architectures of 32 cases of submucosal invasive cancers were analyzed. They were classified into 3 types based on cross-section view: PG and NPG of Shimoda's classification and PG'. Histological architectures were drawn in accordance with these findings. In 7 PG-Ca which consisted of PG only, no apparent correlation was found between the tumor sizes and invasion depth of submucosal layer. However, 12 NPG-Ca which consisted of NPG only and 12 Mixed-Ca which include various cross-section views both showed massive invasion into the submucosa with 1 cm or more in tumor size. Therefore these two types were similar in biological behavior in terms of invasion depth. And degree of submucosal invasion tended to increase in the order of PG-Ca, Mixed-Ca and NPG-Ca. Examinating histological architectures of the Mixed-Ca tumors in details, all of these cancers were consisted of both PG and PG'. Of the 12 Mixed-Ca, 91.7% were proved to be PG dominant type. Macroscopically, I s and II a contained 88.9% and 40.0% of Mixed-Ca, respectively. In conclusion, these results suggest that PG' is a subtype of PG, and PG-Ca have a correlation between tumor invasion and alteration from PG to PG' in histological architectures among submucosal cancers. It is important to clarify morphological features of PG' in margin of I s and II a tumors in diagnosing the depth of early colorectal cancers.

Colon↗
PubMed1995

TEI-3313, a novel prostaglandin A1 derivative, prevents bone loss and enhances bone formation in immobilized male rats.

The effect of a novel prostaglandin A1 derivative, TEI-3313, with the chemical structure 5-[(Z,2E)-4,7-dihydroxy-2-heptenyridene]-4-hydroxy- 2-methylthio-4-(4-phenoxybutyl)-2-cyclopentenone, on bone mineral content was investigated. Seven-week-old Sprague-Dawley rats in which the right hindlimbs were immobilized by sciatic nerve dissection received 1, 10, 100 or 500 micrograms of TEI-3313/kg/day, i.p., for 6 weeks. Control animals were operated on but received vehicle only. Bone mineral content of the femur was measured by single-photon absorptiometry, and biochemical parameters were analyzed. Histomorphometric observations were performed on the proximal metaphysial sections of the tibiae. The administration of up to 500 micrograms/kg of TEI-3313 to rats had no effect on body weight or on serum calcium, inorganic phosphorus and 1 alpha,25 dihydroxy vitamin D3 levels. Immobilization decreased the ash content, calcium content and total bone mineral content of the femur compared with nonimmobilization (unoperated femur). With TEI-3313 administration, changes in these parameters in the immobilized femur were prevented almost to the levels of the nonimmobilized femur, in a dose-dependent manner. The enhancement of bone mineral content was remarkable in the midshaft of the femur. TEI-3313 enhanced ash and calcium content and total bone mineral content in nonimmobilized femurs. Microradiograms showed that TEI-3313, unlike pamidronate and 17 beta-estradiol, had little inhibitory effect on trabecular bone resorption in the proximal portion of the tibia. TEI-3313 not only prevented the bone loss induced by immobilization but also increased bone mass in the nonimmobilized femurs without affecting the levels of 1 alpha,25 dihydroxy vitamin D3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[A case of infarction in the pontine tegmentum involving the bilateral MLF and unilateral paramedian pontine reticular formation].

A 61-year-old man with lesions of the bilateral medial longitudinal fasciculus (MLF) and left paramedian pontine reticular formation (PPRF) caused by an infarction in the pontine tegmentum was reported. On admission, the ocular position of the left eye on forward gaze was fixed at the midline, while the right eye was abducted, and skew deviation was observed. On leftward gaze, neither eye could pass the midline, and on rightward gaze the right eye was abducted with monocular nystagmus, indicating paralytic pontine exotropia. On the fifth day, the bilateral eyes were abducted on forward gaze. On leftward gaze, the left eye was abducted slightly with monocular nystagmus. On rightward gaze, the right eye was abducted with monocular nystagmus. This issue was considered to be walleyed bilateral internuclear ophthalmoplegia (WEBINO). On the 37th day, right MLF syndrome was noted. About 2.5 months later, the disturbances of ocular movement disappeared. T2-weighted MRI showed high signal intensity lesions in the bilateral paramedian portion of the midpontine tegmentum. It suggests that WEBINO is caused by a lesion in the pons, and that paralytic pontine exotropia, one and a half syndrome and WEBINO are considered to be analogous to one another. The associated abnormality of vergence eye movements suggests that these are also generated by the PPRF in the pons.

Cerebellar Ataxia↗
PubMed1995

[A case of multilocular thymic cyst with myasthenia gravis].

We reported a case of 53-year-old male who was admitted to our hospital for ptosis and difficulty in chewing. Because of positive for Tensilon test and high dose anti-acetylcoline receptor antibody, we established diagnosis for myasthenia gravis. Additionally he was pointed out a cystic lesion at anterior superior mediastinum on CT and MRI. As a result we diagnosed him as thymic cyst with myastenia gravis. The extended thymectomy was performed. Histological examination revealed that the mass was a multilocular thymic cyst which is reported by Suster, who suggested that the multilocular thymic cyst arises from processes of reactions to an acquired inflammatory change. There was no report for cases of multilocular thymic cyst with myastenia gravis. MTC-like changes are sometimes presented in association with thymic Hodgkin's disease or thymic seminoma. Malignant transformation of thymic cyst were also reported. So careful examination and evaluation for cystic lesion within thymus are required.

Humans↗
PubMed1995

Structural and functional differences of subspecies of apoA-I-containing lipoprotein in patients with plasma cholesteryl ester transfer protein deficiency.

ApoA-I-containing lipoproteins exist in plasma in two main forms: one contains only apoA-I (LpA-I) while the other contains both apoA-I and apoA-II (LpA-I/A-II). We characterized structural and functional changes of these lipoproteins in six patients with cholesteryl ester transfer protein (CETP) deficiency. In these patients, the amount of LpA-I and LpA-I/A-II had increased significantly. Sixty-five percent of plasma apoA-I was associated with LpA-I/A-II, which indicated that LpA-I/A-II was predominant. The chemical composition of both LpA-I and LpA-I/A-II was characterized by increased ratios of neutral to polar lipid, compared with findings in normal subjects. Particle sizes of these lipoproteins shifted to larger diameter ranges, as compared to the size seen in normal subjects. Incubation of patients' LpA-I and LpA-I/A-II with CETP markedly corrected the chemical and physical abnormalities in these lipoproteins. Cholesterol-reducing capacities of these lipoproteins from macrophage foam cells were significantly lower than in normal controls. Cholesterol esterification rates in LpA-I, LpA-I/A-II, and plasma were significantly lower in patients than in normal controls. We propose that the structure and function of LpA-I and LpA-I/A-II are severely affected in the presence of CETP deficiency.

Apolipoprotein A-I↗
PubMed1995

[Usefulness of thin axial images of computerized tomography angiography for surgery on paraclinoidal carotid artery aneurysms].

A number of surgical experiences with paraclinoidal carotid artery aneurysms have been reported recently. However, neuroradiological examinations can not sufficiently visualize the topographic relations around the aneurysms due to variations in the size of the anterior clinoid process (ACP) or course of the carotid artery in individual cases. Although three-dimensional computerized tomography angiography (3-D-CT-A) is known to be useful for the surgical management of cerebral aneurysms in common locations, its usefulness for paraclinoidal carotid artery aneurysms has not been investigated. Ten cases involving a total of 13 aneurysms located in the clinoid portion of the carotid artery were included in this study according to Al-Radham's classification (Table). The CT scan used was an X Force system manufactured by Toshiba Electric Co, Japan. Non-ionic, iodinated contrast solution, a total of 2ml/kg, was intravenously infused at a rate of 2ml/sec. Helical scanning was begun 30 seconds after initiating the infusion, 1mm pitch/1.5 second/rotation. 3-D images and original images of axial slices were compared to conventional angiography, DSA and surgical findings. The 3-D images of 3-D-CT-A was able to demonstrate both aneurysms located in the C2 segment of the carotid artery (groups I and II), and five of nine carotid cave aneurysms (group III). The aneurysms located more proximally (group IV or V) could not be visualized.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[Two diabetics with hemichorea-hemiballism and striatal lesions].

We report two diabetic patients with hemichorea-hemiballism associated with striatal lesions detected by MRI. Case 1 was a 57-year-old woman. On May 5, 1990, hemichorea-hemiballism of the right upper extremity developed suddenly. The blood glucose level at the time of onset was 695 mg/dl. Plain cranial CT scanning revealed a small high-density lesion in the left putamen. On MRI, this lesion showed a high signal intensity on T1-weighted images, while it showed as an irregular low-intensity area on T2-weighted images. Three and a half months later, the high intensity lesion on MRI decreased gradually and almost disappeared. Case 2 was a 68-year-old woman. In late August 1992, hemichorea-hemiballism of the right upper and lower extremities developed suddenly. The blood glucose level at the time of onset was 365 mg/dl. Plain cranial CT scanning was normal. MRI revealed a high signal intensity lesion involving the left putamen, globus pallidus and head of the caudate nucleus on T1-weighted images, while the lesion was almost isointense on T2-weighted images. The high-intensity lesion on MRI thereafter decreased gradually and disappeared almost completely one year after the onset. It is characteristic that the lesions responsible for hemichorea-hemiballism showed high-intensity areas on T1-weighted MRI in these two diabetics. In the hyperglycemic state, the Krebs cycle is inhibited and GABA is utilized as an energy source. The possibility has been suggested that striatal ischemia is likely to occur in diabetics because the GABA content of the corpus striatum is decreased by hyperglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Evaluation of long-term survivors after pancreatoduodenectomy for pancreatoduodenal carcinoma.

Long-term survivors (> or = 5 years) of pancreatoduodenal carcinoma were evaluated. The absence of retropancreatic invasion seemed to be an important factor for long-term survival in carcinoma of the pancreatic head, carcinoma of the intrapancretic bile duct confined within the bile duct wall, and stage II papilla of Vater carcinoma. The mode of infiltration was INF alpha or INF beta, with a low infiltration tendency. Lymph node metastasis, when present, was confined to the pancreatic head. It is noteworthy that two of the patients with intrapancreatic bile duct cancer had perineural infiltration to the pancreatic head plexus. In patients treated by extended resection, postoperative malnutrition and diarrhea was severe, indicating the importance of long-term nutritional management.

Aged↗
PubMed1995

[Risk of chromosomally unbalanced progeny in prenatal diagnoses of reciprocal translocation carrier].

To obtain new criteria for presuming the existence of chromosomally unbalanced progeny in reciprocal translocation carrier couples, the obstetrical histories of 57 couples were analysed. The chromosomally unbalanced progeny who had been prenatally or postnatally diagnosed were mainly partial trisomies. In contrast with partial trisomies, there were only a few cases of partial monosomies and there were only two cases of chromosomal imbalance derived from 3:1 segregation in gametogenesis. Moreover, the percentage of haploid autosome length (%HAL) of the maternal carriers whose progeny had suffered from chromosomal imbalance was significantly smaller than those of the maternal carriers who had not had progeny with chromosomal imbalance. Based on these results, the following criteria were obtained: 1) Partial trisomies tend to be maintained in pregnancy but partial monosomies do not; Most chromosomally unbalanced zygotes which were induced by 3:1 segregated gametes tend to be spontaneously selected in early pregnancy; 3) When interchanged segments of chromosomes are small in maternal reciprocal translocation carriers, chromosomally unbalanced fetuses tend to be maintained in pregnancy.

Female↗