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T Ogata

Publications and source records attributed to T Ogata.

At least 163 records · Page 9Linked to original sources
PubMed1997

Characterization of the cloned promoter of the human initiation factor 4AI gene.

Protein synthesis initiation factor 4AI (eIF-4AI) is ubiquitously expressed in eucaryotic cells. We characterized the eIF-4AI gene promoter cloned from human fibroblasts. The minimal promoter, localized to a region in the 5'-noncoding region adjacent to the first exon, consisted of approximately 300 base pairs (bp), 80% of which were identical with those in the corresponding mouse promoter. The minimal promoter contained TATA and CAAT motifs and consensus sequences binding to SP1 (three sites) and AP2 (one site). Deletion analyses of the promoter revealed that a 24-bp region near 5'-end of the minimal promoter was essential for the efficient transcription, although the AP2 site in the region was dispensable. A fluorescence polarization assay suggested that the plus strand of the 24-bp region, despite the lack of known consensus sequences binding to transcription factors except for AP2, bound to unknown nuclear protein(s) in a sequence specific manner.

Animals↗
PubMed1997

Ultra-high-resolution scanning electron microscopy of the sarcoplasmic reticulum of the rat atrial myocardial cells.

BACKGROUND: The sarcoplasmic reticulum (SR) of mammalian ventricular and atrial muscles share common features but also differ because T-tubules are rare and extended junctional SR is exclusively seen in the atrium. This scanning electron microscope (SEM) study was undertaken to clarify the three-dimensional organization of the rat atrial SR system. Specific preparations were examined with an ultra-high-resolution SEM. METHODS: Fixed right rat atria were frozen, fractured, and macerated by the aldehyde-osmium-DMSO-osmium method to remove myofibrils and cytoplasmic matrix. Left exposed were mitochondria, SR, and sarcolemma. Dried specimens were then impregnated by osmium-hydrazine and examined without metal coating. RESULTS: In place of conventional T-tubules, a prominent type of sarcotubules, Z-tubules, were found at the Z-line level. Branches from these tubules joined the cisternal SR, which was 100-300 nm in diameter and localized near the Z-line, and formed extensive SR meshworks and polygonal patches. Bulbous swellings, the corbular SR, were also evident. Sarcotubular reticulum completely surrounded each myofibril. The intermyofibrillar SR, especially Z-tubules, joined the peripheral subsarcolemmal SR, which was also arranged as a meshwork and was closely apposed to the sarcolemma. CONCLUSIONS: These SEM observations confirm the organization of the rat atrial SR system and present new, detailed, three-dimensional images of Z-tubules, cisternal SR, extended junctional SR, and peripheral SR, which provide further structural insight.

Animals↗
PubMed1997

Ultra-high-resolution scanning electron microscopy of mitochondria and sarcoplasmic reticulum arrangement in human red, white, and intermediate muscle fibers.

BACKGROUND: Human skeletal muscle fibers are the red, white, and intermediate fibers. They differ in their mitochondrial structure and enzyme activity. Scanning electron microscopy (SEM) was used on specially prepared specimens to determine the distinctive features of mitochondria and sarcoplasmic reticulum (SR) in each fiber type. METHODS: Specimens of human limb muscles were glutaraldehyde fixed, frozen, fractured, and macerated by the aldehyde-osmium-DMSO-osmium procedure to expose large areas of mitochondria and SR. Osmium-hydrazine-impregnated tissues were examined without metal coating by ultra-high-resolution SEM. RESULTS: In white fibers, paired long, thin mitochondria encircled myofibrils at the I-band level. In red fibers, the paired rows of stubby mitochondria at the I-band level were often connected across the A-band to the next row of mitochondria by a slender mitochondrial stalk. Intermediate fiber mitochondria resembled those in red fibers but were longer and thinner. Intermyofibrillar mitochondrial columns were most common in red fibers. All three muscle types had T-tubules along the A-I junction level, and small periodic terminal cisternae formed triads or dyads. Sarcotubules from terminal cisternae formed continuous three-dimensional networks at the I-band level, but intermittent straight sarcotubules, narrow two-dimensional networks, and some axial tubules traversed the A-band. The subsarcolemmal space had continuous two-dimensional SR at the H-band level and a coarse SR network at the I-band. These two SR networks were connected by single A-band sarcotubules. CONCLUSIONS: Mitochondrial shape and configuration were distinctive for each human skeletal muscle fiber type, but the SR was similar in all muscles examined.

Adolescent↗
PubMed1997

Fluid flow induces enhancement of the Egr-1 mRNA level in osteoblast-like cells: involvement of tyrosine kinase and serum.

It is widely accepted that mechanical loading is necessary to construct the architecture of bone and to maintain bone mass. However, the mechanism of how bone cells respond to mechanical stimuli is not known. To clarify this, we stimulated osteoblast-like MC3T3E1 cells by mechanical shaking of the culture dishes and found that the level of the egr-1 gene, which is an early response gene induced by growth factors or serum and encodes a transcription factor, increased 15-45 min after the shaking, with a peak at 30 min. The egr-1 gene product increased 1 h after the shaking. The egr-1 gene elevation was not blocked by prior exposure to indomethacin, saralasin, Rp-cAMP, A23187, and colchicine, and it was blocked partially by cytochalasin D, H-7, and prolonged exposure to TPA. On the other hand, a prior incubation with cycloheximide, DRB, genistein, herbimycin A, and BAPTA/AM completely blocked the egr-1 gene level enhanced by shaking the culture dishes. Moreover, we found that in serum-deprived cells the egr-1 gene response to shaking was not induced. These results suggested that the egr-1 gene response is regulated at the transcriptional level and that it involves tyrosine kinase as well as labile or de novo protein and requires a particular level of intracellular calcium and serum.

Blood Proteins↗
PubMed1997

In vivo longitudinally detected ESR measurements at microwave regions of 300, 700, and 900 MHz in rats treated with a nitroxide radical.

A signal detector of longitudinally detected ESR (LODESR) is independent of the resonant frequency. We developed an in vivo LODESR spectrometer operating in the regions of 300, 700, and 900 MHz. Using this apparatus, we estimated signal intensities at different operating frequencies obtained from non- or high-dielectric loss phantoms that contained nitroxide radical solutions and from live rats that had received a nitroxide radical. Our result, higher signal intensities in the high-dielectric loss samples (such as physiological saline solution and animals) at a lower frequency, shows that the influence of a decrease in dielectric loss dominates over the signal reduction caused by smaller Zeeman splitting. We believe that this finding strongly supports an in vivo ESR resonant frequency that tends to be low.

Animals↗
PubMed1997

Microwave Spectrum, Nuclear Quadrupole Coupling Constants, and Structure of Bromodifluoromethane

The microwave spectrum of bromodifluoromethane, CHBrF2 (Halon 1201) has been studied for the first time from 7 to 40 GHz. A least-squares analysis of the observed c-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows: A = 10199.7186(62) MHz, B = 2903.4150(26) MHz, C = 2360.1521(23) MHz, DeltaJ = 0.660(14) kHz, DeltaJK = 2.87(11) kHz, DeltaK = 8.95 kHz, deltaJ = 0.1344(24) kHz, deltaK = 3.22(15) kHz, chiaa = 521.281(92) MHz, chibb - chicc = -38.32(9) MHz, and |chiac| = 187.1(26) MHz for the 79Br species; A = 10199.5567(54) MHz, B = 2876.5588(20) MHz, C = 2342.3796(18) MHz, DeltaJ = 0.652(12) kHz, DeltaJK = 2.77(9) kHz, DeltaK = 8.21(61) kHz, deltaJ = 0.1300(19) kHz, deltaK = 2.97(13) kHz, chiaa = 435.61(10) MHz, chibb - chicc = -32.08(8) MHz, and |chiac| = 148.5(29) MHz for the 81Br species. The structural parameters are calculated from all these rotational constants and the electronic properties of the carbon-bromine bond in bromodifluoromethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Thyroid cancer in children: report of three cases and a review of the Japanese literature.

We experienced three cases of thyroid cancer in children less than 15 years of age between 1982 and 1995. We herein present these three cases with a review of 141 reported cases of childhood thyroid cancer in Japan. Our patients were 6, 13, and 14 years old. The patients, all girls, were diagnosed as having thyroid cancer based on diagnostic imaging. One of them was also diagnosed by a fine-needle aspiration biopsy (FNAB). One of them underwent subtotal thyroidectomy, and the other two underwent lobectomy. Modified neck dissections were performed on all three. Pathologically, the tumors were all papillary carcinomas. Multiple lymph node metastases were present in all patients. However, the postoperative courses have been good, and there have been no signs of recurrence, 10, 8, and 2 years after their respective operations. In 144 reported cases of childhood thyroid cancer in Japan including ours, the youngest patient was a 2-year-old boy, and the female to male ratio was 2.1:1. FNAB was performed in 25 cases, and 23 (92%) of the tumors were diagnosed as malignant. Histologically, 76% were papillary carcinoma and 20% follicular carcinoma. At operation, lymph node metastases were found in 80% of the cases, and lung metastases in 17%. For treatment, 88% of the patients received a more extensive operation than a lobectomy. Of the 144 patients, 8 died.

Adolescent↗
PubMed1997

In vivo electron spin resonance analysis of nitroxide radicals injected into a rat by a flexible surface-coil-type resonator as an endoscope- or a stethoscope-like device.

The flexible surface-coil-type resonator (FSCR) operating in a 700 MHz microwave electron spin resonance (ESR) system was applied to measure the nitroxide radicals at a specific area in rats. The FSCR was composed of a single-turn coil with a diameter of 5 mm and two flexible coaxial lines of 450 mm in length. For an endoscope-like application, the FSCR was inserted into the rectum of the rat and sequential changes in the ESR signals of the intravenously injected nitroxide radical (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl; TEMPOL or 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy; carbamoyl-PROXYL) were measured. The ESR signal intensity of the nitroxide decreased according to first-order kinetics. For a stethoscope-like application, the FSCR was placed at several sites on the abdominal skin of the rats receiving a subcutaneous injection of carbamoyl-PROXYL, and diffusion and/or metabolism of the radical in the skin was observed.

Animals↗
PubMed1997

Short stature and azoospermia in a patient with Y chromosome long arm deletion.

We report on a 42-year old male with short stature, azoospermia and a wide deletion of long arm of Y chromosome. On physical examination, the patient showed height of 149 cm (< 1 degree centile) and reduced volume (3 ml) and consistency of the testes. On hormonal evaluation, he showed increased serum gonadotropins and normal serum testosterone levels though its HCG stimulated levels were limited. Serum thyroid hormones were normal. Serum GH levels in baseline evaluation as well as after GHRH and GHRH + pyridostigmine administration were normal. Serum IGF I levels were lower than normal in baseline evaluation whereas its response to the GH administration was in the normal range. The bilateral testicular biopsy showed tubular atrophy, hyalinosis, interstitial sclerosis and a histological picture of a Sertoli cell only syndrome. Moreover the patient showed arthropathy, otopathy, small chin, small mouth and truncal obesity. On genetic evaluation, the patient showed a 46,X,delY (pter--q11.1:) karyotype and loss of several DNA loci on Yq. In fact he preserved short arm SRY, centromeric DYZ3 and more proximal euchromatic region Yq loci, including DYS270, DYS271, DYS272, DYS11, DYS273, DYS274, DYS148, DYS275, and missed more distal DNA loci from DYS246 to DYZ2. These results disclosed a wide Y long arm deletion, including all hypothized Yq azoospermia loci (except for AZFa and probably for one of the RBM genes, which lie proximally to the deletion) and possibly the Y-specific growth control region (GCY), mapped between DYS11 and DYS246 loci. This deletion is responsible for the complete azoospermia of the patient and probably also for his short stature, even if other factors could be implicated in the statural impairment. It further possibly allowed to relate the GCY gene(s) to the control of GH or IGF-I receptor or post-receptor pathway, being the alteration of this gene(s) consistent with the hormonal pattern of the patient.

Adult↗
PubMed1997

FISH-deletion mapping defines a 270-kb short stature critical interval in the pseudoautosomal region PAR1 on human sex chromosomes.

Deletions of the pseudoautosomal region (PAR1) of the sex chromosomes have recently been discovered in individuals with short stature, and a minimal common deletion region of 700 kb within PAR1 has subsequently been defined. We have cloned this entire region, which is bounded by the Xp/Yp telomere, as an overlapping cosmid contig. In the present study, we have used fluorescence in situ hybridization (FISH) to study four patients with X-chromosomal rearrangements, two with normal height and two with short stature. Genotype-phenotype correlations have narrowed down the the critical "short stature interval" to a 270-kb region containing the gene with an important role in growth. A minimal tiling path of 6-8 cosmids bridging this interval is now available for interphase and metaphase FISH and provides a valuable tool for diagnostic investigations of patients with idiopathic short stature.

Adolescent↗
PubMed1997

Ovulation induction in a woman with premature ovarian failure resulting from a partial deletion of the X chromosome long arm, 46,X,del(X)(q22).

OBJECTIVE: To report successful ovulation induction in a woman with premature ovarian failure (POF) resulting from a partial Xq deletion. DESIGN: An uncontrolled study. SETTING: University hospital. PATIENT(S): A 27-year-old woman with 46,X,del(X)(q22) who had hypergonadotropic secondary amenorrhea. INTERVENTION(S): Injections of hMG (225 IU/d) for 8 consecutive days after endogenous gonadotropin suppression with a long-acting GnRH agonist (900 micrograms/d) for 12 weeks, together with cyclic sex steroid replacement therapy. MAIN OUTCOME MEASURE(S): Serum concentrations of E2 and P as well as ultrasonography. RESULT(S): Folliculogenesis and ovulation. CONCLUSION(S): Ovulation induction is possible in patients with POF caused by X chromosome aberrations.

Adult↗
PubMed1997

Saxitoxin as a toxic principle of a freshwater puffer, Tetraodon fangi, in Thailand.

Saxitoxin was identified in a freshwater puffer, Tetraodon fangi, which caused food poisoning in Thailand. Tetrodotoxin, a puffer toxin, was not detected in the species by the HPLC-fluorometric analysis, showing that tetrodotoxin is absent or under any detectable level. The result of this study shows that saxitoxin can be a major toxin in puffer.

Animals↗
PubMed1997

Basaloid squamous carcinoma of the larynx: report of a case.

Basaloid squamous carcinoma (BSC) is a rare neoplasm. We present a case of basaloid squamous carcinoma of the larynx in a 57-year-old male patient. The diagnosis before treatment was supraglottic carcinoma (T3N1MO) and biopsy of the larynx revealed a poorly differentiated squamous cell carcinoma. Total laryngectomy and right radical neck dissection were performed, and pathological studies of a specimen removed from the larynx revealed BSC of the larynx. The patient's postoperative progress was uneventful, however, 12 months later he developed lung metastasis of the left side. The patient underwent partial resection of the lung. He developed recurrence of lung metastasis 6 months later. Chemotherapy with cisplatin (CDDP) and vindesine sulfate (VSD) was administered in two courses, but the efficacy was evaluated as no change (NC). At present, 26 months after the first visit, he has been asymptomatic with lung metastasis, and there was no evidence of recurrence in the neck.

Carcinoma, Basosquamous↗
PubMed1997

Temporal brain imaging by a rapid scan ESR-CT system in rats receiving intraperitoneal injection of a methyl ester nitroxide radical.

We performed in vivo ESR-CT (electron spin resonance-computed tomography) on rats' heads, in which the blood-brain barrier-permeable nitroxide radical, 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCAM) was injected intraperitoneally, using a rapid scan ESR-CT system operating at 700 MHz. In a spatiotemporal study we found that different regions of the brain showed differences in the rate of decay of the radical. Repeated injection of PCAM gave clear ESR-CT images of the brain. We think that the present method is useful for evaluating the capacity to eliminate exogenous free radicals in some parts of the brain.

Animals↗
PubMed1997

A CT using longitudinally detected ESR (LODESR-CT) of intraperitoneally injected nitroxide radical in a rat's head.

We have developed an in vivo longitudinally detected ESR (LODESR) imaging system operating at 700 MHz based on a loop-gap resonator and a pair of saddle-type pickup coils. A good linear relationship between the LODESR signal intensity and the applied power in a range up to 15.8 W was obtained. The detection of LODESR signals was barely affected by variations in the resonant properties. The characteristic of LODESR is suitable for in vivo examination. Using this system, we succeeded in obtaining LODESR-CT images of the head region of a rat after the intraperitoneal injection of a nitroxide radical.

Animals↗