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Biomedical subjects

T Miyaji

Publications and source records attributed to T Miyaji.

At least 37 records · Page 2Linked to original sources
PubMed1998

Nucleotide sequence, cloning, and overexpression of the D-threonine dehydrogenase gene from Pseudomonas cruciviae.

D-Threonine dehydrogenase (EC 1.1.1) catalyses the oxidation of the 3-hydroxyl group of D-threonine. The nucleotide sequence of the structural gene, dtdS, for this enzyme from Pseudomonas cruciviae IFO 12047 was determined. The dtdS gene encodes a 292 amino acid polypeptide. The enzyme was overproduced in Escherichia coli cells; the activity was found in cell extracts of the clone. The enzyme showed high sequence similarity to 3-hydroxyisobutyrate dehydrogenases. This is the first example showing the primary structure of an enzyme catalysing the NADP(+)-dependent dehydrogenation of D-threo-3-hydroxyamino acids.

Alcohol Oxidoreductases↗
PubMed1998

Overview and initial results of the very long baseline interferometry space observatory programme

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

Journal Article↗
PubMed1998

Enhancing effect of hydroxypropyl-beta-cyclodextrin on cutaneous penetration and activation of ethyl 4-biphenylyl acetate in hairless mouse skin.

The effect of hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the cutaneous penetration and activation of ethyl 4-biphenylyl acetate (EBA), a prodrug of non-steroidal anti-inflammatory drug 4-biphenylylacetic acid (BPAA), from hydrophilic ointment was investigated, using hairless mouse skin in vitro. When the hydrophilic ointment containing a complex of EBA with HP-beta-CyD was applied to the full-thickness skin, HP-beta-CyD facilitated the penetration of EBA into the skin, the conversion of EBA to BPAA in the epidermis and the transfer of BPAA to the receptor phase. Under the present condition, pre- and post-application of the ointment containing HP-beta-CyD onto the skin did not affect the cutaneous penetration of EBA and its activation. When the ointment containing the EBA:HP-beta-CyD complex was applied to the skin, the flux of BPAA through the tape-stripped skin was greater than that through the full-thickness skin, while the activation of the prodrug in the skin was slowed down by the tape-stripping. When propylene glycol was used as a vehicle, HP-beta-CyD no longer enhanced the cutaneous permeation of BPAA through the full-thickness skin. These results suggest that the enhancing effect of HP-beta-CyD on the cutaneous penetration of EBA would be ascribable largely to an increase in effective concentration of EBA in the ointment. Furthermore, the slow diffusion of EBA solubilized in HP-beta-CyD through the stratum corneum, together with the vehicle effect, could make the prodrug more susceptible to the metabolic process that is active in the epidermis, eventually leading to the facilitated activation of the prodrug.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1997

Ultrastructure of quick-frozen and freeze-substituted chick osteoclasts.

For comparison with chemically fixed osteoclasts, we prepared chick osteoclasts by quick freezing followed by freeze-substitution. In spite of technical difficulties this demonstrated that osteoclasts can be satisfactorily frozen in situ by the metal contact method. Ultrastructural differences were revealed between conventional fixation and quick freezing. Compared with conventional fixation, the quick freezing method appeared to improve preservation: (1) a discrete trilaminar plasma membrane and other intracellular membranes showed a smooth profile without undulation or rupture; (2) cytoskeletal components appeared to be clearer, straighter, and more numerous; (3) the interior of the ruffled finger contained interconnected lattice structures whereas highly organised microfilaments were seen in the clear zone; (4) well developed tubulovesicular structures (TVSs) that branched or anastomosed with each other were revealed in the cytoplasm; (5) the contents of intracellular membrane systems including the nuclear envelope, endoplasmic reticulum, and Golgi complex were stained to a various extent; (6) vesicles and vacuoles were much smaller, round and well-defined with electron-dense contents; (7) crystalline structures were seen at the extracellular channels of the ruffled border, in the lumen of TVSs, and in vesicles; (8) in some instances mitochondrial granules were visible; (9) within the resorptive lacuna, osteoclasts adhered to the degraded bone matrix without any intervening empty space.

Animals↗
PubMed1996

A comparison of four infrared tympanic thermometers with tympanic membrane temperatures measured by thermocouples.

PURPOSE: To compare measurements made with four infrared tympanic thermometers (Genius, Thermopit, Quickthermo, and Thermoscan) with those recorded from thermocouples positioned in the contralateral ear. METHODS: Four tympanic thermometers were evaluated in 50 healthy volunteers (12 female and 38 male). Temperatures were measured, in random order, at the right tympanic membrane four times and the highest temperature was considered to be the true value measured by each thermometer. The control temperature was measured at the left tympanic membrane using Mon-a-Therm thermocouples. RESULTS: The tympanic membrane temperature measured by Genius correlated best with the Mon-a-therm measurement (TM) (r = 0.74). The tympanic membrane temperatures measured by Thermopit, Quickthermo, and Thermoscan correlated moderately with TM (r = 0.56, 0.63, and 0.58, respectively). Mean differences between TM and each temperature (TG, TTP, TQ, and TTS) were -0.3, 0.73, 0.42, and -0.3 degrees C, respectively. Likewise standard deviations were 0.33, 0.37, 0.35, and 0.35. CONCLUSION: We conclude that all but the Thermopit (TTP) are similarly useful for the management of patients during anaesthesia.

Adult↗
PubMed1996

Uninephrectomy reduces apoptotic cell death and enhances renal tubular cell regeneration in ischemic ARF in rats.

Contralateral uninephrectomy attenuates unilateral ischemic renal injury functionally and morphologically. In this study we investigated the effects of uninephrectomy on apoptotic renal cell death and tubular regeneration in ischemic acute renal failure (ARF) in rats. Unilateral ischemic injury was provoked by a 60-min left renal artery occlusion in right-nephrectomized (Nx) and sham-nephrectomized (sham-Nx) rats. Uninephrectomy attenuated tubular damage 48 h following the renal ischemia Apoptotic cells were found in renal tissue as early as 3 h after reperfusion and increased in number by 12 h. The "ladder" pattern of DNA fragments on agarose gel electrophoresis was also apparent in ischemic kidney. Uninephrectomy reduced apoptotic cells and DNA fragmentation. The expression of proliferating cell nuclear antigen (PCNA) could be seen 24 h after reperfusion and progressively increased thereafter PCNA expression in ischemic kidney was greater in Nx than sham-Nx rats at 24 h after renal reperfusion. These data suggest that uninephrectomy reduces apoptotic cells and DNA fragmentation and enhances PCNA expression. The reduced apoptotic cell death and enhanced cell regeneration may be importantly involved in the uninephrectomy-induced attenuation of ischemic acute renal failure in rats.

Acute Kidney Injury↗
PubMed1996

Possible enhancing mechanism of the cutaneous permeation of 4-biphenylylacetic acid by beta-cyclodextrin derivatives in hydrophilic ointment.

The enhancing effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the percutaneous absorption of 4-biphenylylacetic acid (BPAA), a nonsteroidal anti-inflammatory drug, in hydrophilic ointment were studied and compared with the parent beta-cyclodextrin (beta-CyD). 13C-NMR measurements suggested that the biphenyl group of BPAA is preferably included within the cavity of three beta-CyDs. The three beta-CyDs remarkably enhanced the release of BPAA from the hydrophilic ointment base and the in vitro cutaneous permeation, depending on the increase in solubility of BPAA in the ointment base. Pretreatment of the ointment containing DM-beta-CyD or HP-beta-CyD onto the isolated skin of hairless mice, however, provided no effects on the skin permeation of BPAA. When propylene glycol was used as a vehicle, both the release rate and cutaneous permeation parameters showed no appreciable difference between BPAA alone and its HP-beta-CyD complex, because the solubilities of BPAA and its HP-beta-CyD complex were almost comparable in the vehicle. The present results suggested that the enhancing effect of beta-CyDs on the percutaneous absorption of BPAA can be mainly ascribed to an increase in the solubility of BPAA in the hydrophilic ointment.

Animals↗
PubMed1996

A rare case of ectopic antidiuretic hormone-producing pancreatic adenocarcinoma: new diagnostic approach.

We describe a 73-year old man with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) due to an ectopic ADH-producing pancreatic adenocarcinoma. His laboratory findings showed marked hyponatremia, and the water load test showed uncontrolled ADH secretion. The imaging studies revealed pancreatic body cancer. Histological examination revealed an adenocarcinoma of the pancreas, which was positive for ADH immuno-staining. The ADH in the tumor extract was 53.3 pg/g wet weight. In attempt to diagnose ADH-production from the tumor, the ADH in his pancreatic juice was measured and found to be 2.1 pg/ml. We conclude that it is valid to measure the ADH in pancreatic juice to diagnose ectopic ADH production by tumors.

Adenocarcinoma↗
PubMed1995

Isoflurane and sevoflurane produce a dose-dependent reduction in the shivering threshold in rabbits.

All general anesthetics markedly impair thermoregulatory responses; nonetheless, sufficient hyperthermia or hypothermia will trigger most protective reflexes. Shivering, however, remains an exception among thermo-regulatory responses: it is common during postanesthetic recovery, but is rare at typical anesthetic concentrations. This observation suggests that general anesthesia impairs shivering far more than other thermoregulatory defenses. Accordingly, we tested the hypothesis that low concentrations of isoflurane and sevoflurane would virtually obliterate shivering. Japanese white rabbits were anesthetized with isoflurane or sevoflurane at end-tidal concentrations of 0.2, 0.3, and 0.4 minimum alveolar anesthetic concentration (MAC) (n = 6 in each group); the normal core temperature for these rabbits is approximately 39 degrees C. Core temperatures were subsequently reduced by a water-perfused thermode positioned in the colon. The core temperature triggering shivering identified the threshold for this response. Five of the six rabbits given 0.2 MAC isoflurane shivered at a mean core temperature of 36.3 +/- 0.3 degrees C (mean +/- SD), and one rabbit failed to shiver at a minimum core temperature of 35.0 degrees C. Four of the six rabbits given 0.3 MAC isoflurane shivered at a mean core temperature of 36.2 +/- 0.6 degrees C, and two of these rabbits failed to shiver at a minimum core temperature of 35.0 degrees C. However, no rabbit given 0.4 MAC isoflurane shivered, even at minimum core temperatures of 35.0 degrees C. All of the rabbits given 0.2 MAC sevoflurane shivered at a mean core temperature of 36.6 +/- 0.7 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthetics↗
PubMed1994

Crystallization and X-ray studies of the DNA-binding domain of OmpR protein, a positive regulator involved in activation of osmoregulatory genes in Escherichia coli.

The OmpR protein of Escherichia coli is a positive regulator involved in the activation of expression of ompC and ompF genes encoding the major outer membrane protein OmpC and OmpF, respectively. The C-terminal half domain of OmpR (OmpR-C), which is responsible for DNA-binding, has been crystallized using the hanging drop vapour diffusion method. X-ray studies show that the crystals belong to the trigonal space group P3(1)21 (or P3(2)21) with a = b = 60.4 A, c = 58.8 A and gamma = 120 degrees. The asymmetric unit contains one molecule. The crystals diffract to at least 3 A resolution and are suitable for X-ray structure analysis.

Bacterial Outer Membrane Proteins↗
PubMed1993

A new infrared tympanic thermometer in surgery and anesthesia.

We have evaluated a new infrared tympanic thermometer, IT-10, as an intraoperative temperature monitor in patients with or without open abdominal surgery. It determines temperature by measuring infrared radiation given off by a warm object. Temperatures measured with this device were closely correlated with those measured with rectal and bladder thermometries. We conclude that this new tympanic thermometer is safe, convenient, accurate, and easily usable in the clinical situation.

Journal Article↗
PubMed1993

[A case of round atelectasis related to spontaneous pneumothorax in a patient with neurilemmomatosis].

A 60-year-old man was admitted to our department for investigation of abnormal shadows on his chest X-ray. He had been diagnosed as having neurilemmomatosis in 1987. His chest X-ray showed nodular shadows in left S5 and S8 and localized spontaneous pneumothorax in left lung field. The nodular shadows, which were in contact with thickening of the pleura, showed curved shadows of bronchi and vessels (so-called comet tail sign). We suspected that they were round atelectasis, but to confirm the diagnosis and to treat the pneumothorax, limited resection of the lung and resection of the bulla were performed. The diagnosis of round atelectasis was confirmed by histological findings. Round atelectasis related to spontaneous pneumothorax is a very rare condition; however, we consider this to be an important case for understanding the pathogenesis of round atelectasis.

Humans↗
PubMed1992

[Use of water-soluble beta-cyclodextrin derivatives as carriers of anti-inflammatory drug biphenylylacetic acid in rectal delivery].

To improve the rectal delivery of an anti-inflammatory drug, biphenylylacetic acid (BPAA), the use of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and heptakis (2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) was investigated. Inclusion complex formations of BPAA with both beta-CyDs in a molar ratio of 1:1 in water were ascertained, and their stability constants were determined. The dissolution of BPAA in water and the release of BPAA from an oleaginous suppository (Witepsol H-5) were significantly increased by beta-CyDs, depending on the magnitude of the stability constants of the water-soluble complexes. However, the serum levels of BPAA after rectal administration of the suppositories containing BPAA or its beta-CyDs complexes in rats increased in the order of BPAA alone much less than DM-beta-CyD less than or equal to HP-beta-CyD complex. The in situ recirculation study revealed that the greater the stability constant of the complex, the lesser was the absorption of BPAA from the rectal lumen of rats under the solution state. Both in vivo and in situ studies demonstrated that rather high amount of HP-beta-CyD (about 20% of dose) was absorbable from the rat's rectum, compared with DM-beta-CyD (less than 5% of dose), suggesting the possibility of the permeation of BPAA through the rectal membrane in the form of HP-beta-CyD complex. Furthermore, DM-beta-CyD and HP-beta-CyD significantly reduced the irritation of the rectal mucosa caused by BPAA after the administration of the suppositories to rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Rectal↗