Biomedical subjects

J Hattori

Publications and source records attributed to J Hattori.

At least 37 records · Page 2Linked to original sources

PubMed1998

Effects of troglitazone on hepatic and peripheral insulin resistance induced by growth hormone excess in rats.

It is well known that short-term growth hormone (GH) administration in humans and animals induces insulin resistance and glucose intolerance. The purpose of the present study was to clarify whether troglitazone, a new insulin-sensitizing drug of the thiazolidinedione class, counteracts the insulin antagonistic effects of recombinant human (rh) GH on glucose metabolism in rats. Male Wistar rats weighing 184 to 226 g were treated either with rhGH (n = 8) or rhGH plus troglitazone (n = 8). rhGH (20 IU/kg body weight/d) was given by subcutaneous injection twice daily for 2 days. Troglitazone was given at 100 mg/kg/d orally for 5 days before and 2 days during rhGH. Saline was injected to the control rats (n = 7). Euglycemic clamp studies with an insulin infusion rate of 8 mU/kg/min were performed in these rats after an overnight fast. Hepatic glucose output (HGO), glucose infusion rate (GIR), and glucose disappearance rate (GDR) were measured. Fasting levels of plasma glucose (6.6 +/- 0.1, 6.1 +/- 0.3, 6.5 +/- 0.2 mmol/L), insulin (187.5 +/- 24.1, 206.4 +/- 24.1, 182.3 +/- 31.0 pmol/L), and serum free fatty acid (FFA) (1.58 +/- 0.18, 1.43 +/- 0.16, 1.61 +/- 0.25 mEq/L) were comparable among rats treated with rhGH, rhGH plus troglitazone, and controls, respectively. Basal HGO was also comparable among the three treatment groups. HGO was suppressed significantly during the hyperinsulinemic glucose clamp in control rats, but not in rhGH rats. When troglitazone was coadministered with rhGH, suppressibility of HGO during the glucose clamp was comparable to that of controls. GIR (13.5 +/- 4.5 v 24.1 +/- 4.1 mg/kg/min) and GDR (18.1 +/- 5.8 v 30.3 +/- 5.2 mg/kg/min) were decreased by rhGH treatment compared with control values. They returned to normal levels in rats treated with both rhGH and troglitazone (GIR, 22.4 +/- 5.9; GDR, 24.7 +/- 7.1). From these results, it is evident that rhGH treatment impaired insulin's ability to suppress HGO and stimulate peripheral glucose utilization. Troglitazone could block the insulin antagonistic effects of GH on hepatic glucose output and peripheral glucose utilization.

Administration, Oral↗

PubMed1998

Effects of troglitazone on dexamethasone-induced insulin resistance in rats.

Troglitazone, a thiazolidinedione derivative, has been shown to counteract insulin resistance in obesity and non-insulin-dependent diabetes mellitus (NIDDM). To test its effects on dexamethasone-induced insulin resistance, we measured hepatic glucose production (HGP) and the insulin-stimulated glucose disposal rate (Rd) by a euglycemic-hyperinsulinemic glucose clamp technique coupled with 3-3H-glucose infusion in male Wistar rats treated with low-dose dexamethasone ([LoDex] 0.05 mg/kg/d, n = 7), high-dose dexamethasone ([HiDex] 0.1 mg/kg/d, n = 7), or dexamethasone plus troglitazone (LoDex + T, n = 8; HiDex + T, n = 6). Dexamethasone was injected subcutaneously for 4 days. Troglitazone was administered orally at 20 mg/d for 3 days before and for 4 days along with the dexamethasone treatment. The glucose clamp study was performed after an overnight fast in chronically catheterized conscious rats with a continuous insulin infusion of 57.4 pmol/kg/min. Basal HGP was comparable among the control (45.8 +/- 2.1 micromol/kg/min, n = 7), LoDex (47.9 +/- 4.7 micromol/kg/min), LoDex + T (46.0 +/- 2.6 micromol/kg/min), and HiDex + T (54.7 +/- 3.4 micromol/kg/min) groups. It increased about twofold in the HiDex group (80.1 +/- 5.2 micromol/kg/min, P < .05 v control). Under hyperinsulinemia, HGP was suppressed to a similar level in the control (11.3 +/- 8.8 micromol/kg/min), LoDex (10.2 +/- 8.4 micromol/kg/min), and LoDex + T (7.8 +/- 7.9 micromol/kg/min) groups. The suppressive effect of insulin on steady-state HGP during the clamp was impaired in HiDex (63.7 +/- 9.7 micromol/kg/min, P < .05) and HiDex + T (64.0 +/- 6.5 micromol/kg/min, P < .05). Rd decreased 27% in LoDex (81.5 +/- 5.8 micromol/kg/min, P < .05) and 36% in HiDex (71.3 +/- 9.4 micromol/kg/min, P < .05) compared with the controls (111.4 +/- 7.4 micromol/kg/min). Troglitazone prevented the decrease in Rd in LoDex + T (102.6 +/- 5.7 micromol/kg/min), but not in HiDex + T (67.0 +/- 6.4 micromol/kg/min). These results indicate that the development of peripheral insulin resistance was prevented by troglitazone in LoDex rats. Troglitazone may be a useful drug to treat steroid-induced diabetes.

Animals↗

PubMed1998

Photosensitive fits elicited by TV animation: an electroencephalographic study.

BACKGROUND: We carried out a clinical and electroencephalographic (EEG) study to reveal the pathophysiology of acute symptoms elicited by a TV animation program. METHODS: Clinical data and EEG were obtained from 20 patients ranging in age from 6 to 30 years. A pattern presentation and an intermittent photic stimulation were performed. RESULTS: Of 20 patients, 13 had a convulsion and seven had other symptoms, mainly nausea and/or vomiting. A photoparoxysmal response (PPR) was confirmed in 12 of 13 patients (92.3%) who had a convulsion. Only one of seven patients (14.3%) without a convulsion showed a PPR. The incidence of PPR was significantly higher in patients with convulsion than those without convulsion. There were no significant differences in the family history of convulsion, gender, parameters associated with TV watching and basic EEG between the two groups. All patients with PPR had a convulsion or consciousness disturbance. CONCLUSION: Acute symptoms, such as convulsion and impairment of consciousness, are supposed to be based on photosensitivity.

Adolescent↗

PubMed1997

Bnm1, a Brassica pollen-specific gene.

cDNA and genomic clones of a new pollen-specific gene, Bnm1, have been isolated from Brassica napus cv. Topas. The gene contains an open reading frame of 546 bp and a single intron of 362 bp. A comparison of the deduced amino acid sequence with sequences in data banks did not show similarity with known proteins. Northern blot analysis of developing pollen showed that Bnm1 mRNA was first detected in bicellular pollen and accumulated to higher levels in tricellular pollen. Bnm1 mRNA was not detected in leaves, stems, roots, pistils, seeds or pollen-derived embryos. RNA in situ hybridization of whole flower buds confirmed that Bnm1 was pollen-specific and expressed late in development. A promoter fragment of the Bnm1 gene fused to the gusA reporter gene yielded similar patterns of tissue specificity and developmental regulation in transgenic B. napus cv. Westar plants; however, the promoter was also active during the early stages of pollen development. The Bnm1 gene, cloned in this study, was derived from the A genome of the allotetraploid species B. napus (AACC). Southern blot analysis indicated that sequences similar to the Bnm1 gene were found in both A and C Brassica genomes. Related sequences were found in all 10 members of the Brassiceae tribe examined, but were not present in all tribes of the Brassicaceae family.

Brassica↗

PubMed1996

Analysis of a hotspot for deletion formation within the intron of the chloroplast trnI gene.

The chloroplast genomes of higher plants encode several tRNA genes that contain highly conserved type II introns. Using primers specific to conserved 5' and 3' regions within the introns of the genes trnA (tRNA-ala) and trnI (tRNA-ile) we have PCR amplified parts of these introns from 36 plant species representing a wide range of plant families. Deletions were found in the introns of both tRNA genes. Fourteen species had detectable deletions within the intron of trnI and four species within the intron of trnA. The occurrence of these deletions among the various plant families suggests that the events leading to the formation of these deletions occurred independently many times during the evolution of higher plants. Analysis of the amplified PCR products from the trnI intron suggests that these independent deletions may not be random but appear to fall into two size classes. Several members of each class were cloned and sequenced and the end points of the deletions were mapped. The 3' ends of all deletions studied terminate within the same short region. The 5' ends of the deletions map to two different regions, giving rise to the two size classes. These two 5' deletion endpoint regions show some sequence similarity. Only two of the identified deletions contain directly repeated sequences at the deletion endpoints, a feature associated with homologous recombination. Our results suggest that within the trnI intron, there are preferred sites or "hotspots" for deletion formation involving a novel imprecise recombination mechanism. The significance of these sequences and possible mechanisms for deletion formation are discussed.

Base Sequence↗

PubMed1995

An acetohydroxy acid synthase mutant reveals a single site involved in multiple herbicide resistance.

Acetohydroxy acid synthase (AHAS) is an essential enzyme for many organisms as it catalyzes the first step in the biosynthesis of the branched-chain amino acids valine, isoleucine, and leucine. The enzyme is under allosteric control by these amino acids. It is also inhibited by several classes of herbicides, such as the sulfonylureas, imidazolinones and triazolopyrimidines, that are believed to bind to a relic quinone-binding site. In this study, a mutant allele of AHAS3 responsible for sulfonylurea resistance in a Brassica napus cell line was isolated. Sequence analyses predicted a single amino acid change (557 Trp-->Leu) within a conserved region of AHAS. Expression in transgenic plants conferred strong resistance to the three classes of herbicides, revealing a single site essential for the binding of all the herbicide classes. The mutation did not appear to affect feedback inhibition by the branched-chain amino acids in plants.

Acetolactate Synthase↗

PubMed1995

Inactivation of blasticidin S by Bacillus cereus. V. Purification and characterization of blasticidin S-deaminase mediated by a plasmid from blasticidin S resistant Bacillus cereus K55-S1.

Blasticidin S (BS) deaminase (BSR) from a BS-resistant strain, Bacillus cereus K55-S1, was purified to homogeneity. Molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by gel filtration on HPLC are about 15500 and 35000, respectively, indicating the enzyme is a homodimer. The amino acid composition and N-terminal sequence of BSR are the same as those deduced from the nucleotide sequence of the BS-resistant gene, bsr. The optimum temperature and pH for enzyme activity are 60-65 degrees C and near 10.0, respectively. The activity of BSR is inhibited by Cu2+, Hg2+, and p-chloromercuric benzoate (PCMB). Inhibition by PCMB or HgCl2 is reversible by the addition of SH reagents. The enzyme catalyzes the deamination of BS and its derivatives, but not cytosine nucleosides.

Aminohydrolases↗

PubMed1994

T-DNA tagging of a seed coat-specific cryptic promoter in tobacco.

T-DNA tagging with a promoterless beta-glucuronidase (GUS) gene generated a transgenic Nicotiana tabacum plant that expressed GUS activity only in developing seed coats. Cloning and deletion analysis of the GUS fusion revealed that the promoter responsible for seed coat specificity was located in the plant DNA proximal to the GUS gene. A 3.3 kb fragment corresponding to the insertion site was isolated from untransformed plants. No long open reading frames were detected in this region. Northern blots and RNase protection assays failed to detect transcripts from this region in untransformed plants. Furthermore, the insertion site was situated within the N. tomentosiformis genome of the allotetraploid species N. tabacum, in a region which is not conserved within the genus Nicotiana. It is concluded that seed coat-specific GUS expression in this transgenic plant resulted from T-DNA insertion next to a cryptic promoter. These results suggest that at least some of the fusions generated to marker genes in promoter trapping studies are not associated with conventional gene promoters. The possibility that similar insertion events play a role in gene evolution is discussed.

Amino Acid Sequence↗

PubMed1994

Construction and expression of a metallothionein-beta-glucuronidase gene fusion.

A gene fusion consisting of the Chinese hamster metallothionein II and beta-glucuronidase coding regions was constructed. The fusion protein expressed in Escherichia coli retained cadmium-binding capacity and beta-glucuronidase activity. When expressed from the constitutive 35S promoter in transgenic tobacco, the levels of 109Cd accumulation in leaves were reduced to about 70% of those in untransformed control plants. Metallothionin-beta-glucuronidase did not sequester a significant proportion of the leaf 109Cd taken up through the roots in vitro and therefore a sink for Cd was not created.

Animals↗

PubMed1993

Field performance and heavy metal concentrations of transgenic flue-cured tobacco expressing a mammalian metallothionein-beta-glucuronidase gene fusion.

Cadmium (Cd) is a nonessential heavy metal that can cause acute and chronic illness in humans. Some plant species such as tobacco (Nicotiana tabacum L.) tend to accumulate high levels of Cd in leaf tissue, the consumed portion of the plant. Tissue-specific expression of mammalian metallothionein has been suggested as a means of partitioning Cd in nonconsumed portions of transgenic plants. The purpose of the experiment reported here was to evaluate Cd concentration and agronomic performance of four field-grown transgenic tobacco lines harbouring a metallothionein-beta-glucuronidase (MG) gene fusion driven by the constitutive 35S promoter of cauliflower mosaic virus. The trial was grown in a region of Canada known to have high background levels of Cd. The agronomic evaluation showed that some of the transgenic lines were equal to, while others performed more poorly than, the untransformed control for yield, days to flower, and leaf number. Gene expression measured by beta-glucuronidase activity showed that all of the transgenic lines expressed the MG gene in the upper portion of the plant. One line did not express the MG gene in the roots. Cd levels in the leaf tissue of transformed lines were not significantly different from the untransformed control.

Animals↗

PubMed1993

Thyroid hormone autoantibodies in patients with untreated Graves' disease: with special reference to age.

We examined thyroid hormone autoantibodies (THAA) in 170 patients with untreated Graves' disease (145 women and 25 men, aged 8-74 yr). THAA were found in 28 patients (16.5%, group I), but not detected in the remaining 142 patients (83.5%, group II). Neither the male/female ratio nor prevalence of antithyroid antibodies (Ab) (thyroglobulin Ab and/or microsomal Ab) differed between the 2 groups. The mean age of group I was significantly lower than that of group II. Furthermore, prevalence in group I decreased progressively with age. In addition, there was a negative correlation between T4 Ab titers (but not T3 Ab titers) and age in group I. These results indicate that the production of THAA, especially T4 Ab, is influenced by age in untreated Graves' patients. The present study also indicates that the age of the patients is one of the important factors causing different results concerning the prevalence of THAA in Graves' disease.

Adolescent↗

PubMed1993

Hyperthyroidism with potent thyroid-stimulation-blocking antibodies and negative thyroid-stimulating antibodies after subtotal thyroidectomy for Graves' disease with follicular thyroid carcinoma.

A 39-year-old woman with Graves' disease associated with follicular thyroid carcinoma underwent subtotal thyroidectomy. TSH-binding inhibitor immunoglobulins (TBII) were positive, whereas thyroid-stimulating antibodies (TSAb) and thyroid-stimulation-blocking antibodies (TSBAb) were both negative before the operation. After the operation, TBII markedly increased above the pretreatment value. TSBAb became positive 3 months after the operation and then their activity increased, while TSAb remained negative after the operation. Subtotal thyroidectomy may have influenced the development of TSBAb in this patient. Irrespective of these findings, the patient became hyperthyroid again several months after the operation.

Adenocarcinoma↗

PubMed1993

[A case of pulmonary alveolar microlithiasis].

The patient was a 42-year-old man. When he was a third grade pupil of elementary school, he was diagnosed as having miliary tuberculosis. He was absent from school for 2 years for the treatment of the disease. However, miliary tuberculosis did not improve in spite of 2 years of treatment. At that time he was diagnosed as having pulmonary alveolar microlithiasis. He did not receive any treatment for the following 30 years. Recently, he visited our department because of occasional chest pain. The following tests were performed; chest CT, tomography, respiratory function test, RI test (99mTc bone scintigram and 67Ga scintigram) and bronchoscopy. Bronchoalveolar lavage (BAL) was performed of B5b, and transbronchial lung biopsy (TBLB) of left B5b, B8b, B9b and B10b to make the accurate diagnosis of pulmonary alveolar microlithiasis. This case of pulmonary alveolar microlithiasis with a protracted course of 30 years (in which chest X-ray films taken 27 years ago were available) is reported together with a discussion of the literature.

Adult↗

PubMed1992

Multiple resistance to sulfonylureas and imidazolinones conferred by an acetohydroxyacid synthase gene with separate mutations for selective resistance.

The acetohydroxyacid synthase (AHAS) gene from the Arabidopsis thaliana mutant line GH90 carrying the imidazolinone resistance allele imr1 was cloned. Expression of the AHAS gene under the control of the CaMV 35S promoter in transgenic tobacco resulted in selective imidazolinone resistance, confirming that the single base-pair change found near the 3' end of the coding region of this gene is responsible for imidazolinone resistance. A chimeric AHAS gene containing both the imr1 mutation and the csr1 mutation, responsible for selective resistance to sulfonylurea herbicides, was constructed. It conferred on transgenic tobacco plants resistance to both sulfonylurea and imidazolinone herbicides. The data illustrate that a multiple-resistance phenotype can be achieved in an AHAS gene through combinations of separate mutations, each of which individually confers resistance to only one class of herbicides.

Acetolactate Synthase↗

PubMed1992

Non-suppressed thyroidal radioactive iodine uptake (RAIU) in thyrotoxic phase in a case of subacute thyroiditis with thyroid-stimulating antibodies (TSAb).

In this paper, we report a 49-year-old female with subacute thyroiditis who had thyroid-stimulating antibodies (TSAb) and thyroid-stimulation-blocking antibodies (TSBAb) in serum. Although she was in the thyrotoxic phase and TSH was suppressed in May, 1990, her radioactive iodine uptake (RAIU) was not suppressed (35.5%) and a thyroid scan disclosed a diffuse goiter with no defect. Serum assays revealed the presence of TSAb, but TSBAb were negative. In August, 1990, the right lobe became undetectable by thyroid scan when the RAIU was 20.7% with the TSH level remaining suppressed. At that time, TSAb were negative, while TSBAb were positive. When the RAIU was 31.1% in October, 1990, both thyroid lobes became visible and the TSH level was normalized. TSBAb became negative, and although TSAb reappeared it later became undetectable. These results indicate that the changes in the patient's thyroid scan and RAIU were attributable to the presence of TSAb.

Autoantibodies↗

PubMed1992

[A case report of thrombosed Björk-Shiley valve in aortic position diagnosed using transtelephone PCG monitoring].

We report a successful elective re-AVR and MVR 10 years after AVR with aortic root enlargement and OMC. The patient was a 41-year-old woman. The diagnosis of thrombosed Björk-Shiley (B-S) valve was first suspected by transtelephone PCG monitoring and reconfirmed by the frequency analysis of prosthetic valve sounds and the aortography preoperatively. The thrombosis was 15 x 8 x 6.5 mm in size and located at the minor orifice of B-S valve, extending to the strut. The transtelephone PCG was useful in analyzing prosthetic valve sounds for patients especially living away from the hospital.

Adult↗

PubMed1991

Molecular characterization and genetic origin of the Brassica napus acetohydroxyacid synthase multigene family.

The Brassica napus rapeseed cultivar Topas contains an acetohydroxyacid synthase (AHAS) multigene family consisting of five members (AHAS 1-5). DNA sequence analysis indicate that AHAS1 and AHAS3 share extensive homology. They probably encode the AHAS enzymes essential for plant growth and development. AHAS2 has diverged significantly from AHAS1 and AHAS3 and has unique features in the coding region of the mature polypeptide, transit peptide and upstream non-coding DNA, which raises the possibility that it has a distinct function. AHAS4 and AHAS5 have interrupted coding regions and may be defective. The complexity of the AHAS multigene family in the allotetraploid species B. napus is much greater than reported for Arabidopsis thaliana and Nicotiana tabacum. Analysis of the presumptive progenitor diploid species B. campestris and B. oleracea indicated that AHAS2, AHAS3 and AHAS4 originate from the A genome, whereas AHAS1 and AHAS5 originate from the C genome. Further variation within each of the AHAS genes in these species was found.

Acetolactate Synthase↗

PubMed1989

[Clinical evaluation of perioperative myocardial infarction as a complication of valve replacement].

Perioperative myocardial infarction (PMI) is a well-known complication of coronary artery surgery, but rarely encountered in valvular surgery. We have experienced 6 cases of valve replacement with PMI, using blood cardioplegia since 1979. Those patients (5 men, one woman; mean age 47 +/- 8 years) had no previous angina, and preoperative CAG revealed no significant stenosis. Three patients were reoperative cases. A diagnosis of PMI was established by the following criteria; an abnormal increase in maxCPK-MB (greater than 150 IU/l), new Q waves at ECG, positive 99mTc-PYP scan (grade 3-4). The area of PMI was inferior in 4 patients, posterior in one, and anterior infarction was seen in only one case. Three cases required IABP, but all 6 cases showed good exercise capacity by Treadmill exercise test in late stage. Several factors are thought to be the cause of PMI at valvular surgery; such as coronary air embolism, perioperative coronary spasm, inappropriate topical hypothermia, etc. Prognosis is not necessarily poor, however much attention should be paid to prevent PMI in valve replacement.

Adult↗