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Biomedical subjects

H Ishihara

Publications and source records attributed to H Ishihara.

At least 487 records · Page 27Linked to original sources
PubMed1988

Unexpected translation initiation within the coding region of eukaryotic genes expressed in Escherichia coli.

When expressing several eukaryotic genes in Escherichia coli, we observed N-terminally truncated proteins which were attributed to translation initiation at downstream AUG codons. These AUG codons are located between 4 and 20 nucleotides 3' from sequences resembling bacterial SD elements. Although the presence of such downstream SD sequences is not sufficient for downstream initiation to occur, in two cases their removal abolishes synthesis of the truncated proteins. In one construct, a potential hairpin-loop structure is likely to inhibit translation initiation at the correct site and favor downstream initiation.

Base Sequence↗
PubMed1988

Structural analyses of asparagine-linked oligosaccharides of porcine pancreatic kallikrein.

The structures of asparagine-linked oligosaccharides of porcine pancreatic beta-kallikrein are reported. Asparagine-linked neutral oligosaccharides were released by N-oligosaccharide glycopeptidase digestion, and the reducing ends of the oligosaccharides were derivatized with a fluorescent reagent, 2-aminopyridine. The mixture of pyridylamino oligosaccharides was separated by reverse-phase and amide-adsorption high-performance liquid chromatography. The pyridylamino oligosaccharides were separated into more than 50 kinds of oligosaccharides. The structures of 5 kinds of triantennary and 12 kinds of tetraantennary oligosaccharides were determined by the use of high-resolution proton nuclear magnetic resonance spectroscopy and methylation analysis. Furthermore, the structures of five kinds of oligomannose-type oligosaccharides were elucidated by a combination of exoglycosidase digestion and high-performance liquid chromatography. 1H NMR data for 14 out of the 17 kinds of N-acetyllactosamine-type oligosaccharides reported here have not previously been described in the literature. (1) It has been shown that fucose containing tri- and tetraantennary oligosaccharides is predominant in porcine pancreatic beta-kallikrein B. (2) It has also been shown that the heterogeneity of the structure in these types of oligosaccharides is derived from the variety of the positions of galactose residues linked to outer N-acetylglucosamine residues. (3) The distribution of oligosaccharides into two glycosylation sites, asparagine-95 and asparagine-239, of beta-kallikrein B was determined. It has been found that oligomannose-type oligosaccharides are exclusively present at asparagine-239, although N-acetyllactosamine-type oligosaccharides occur at both glycosylation sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Comparative structural study of N-linked oligosaccharides of urinary and recombinant erythropoietins.

The structures of the N-linked oligosaccharides of the urinary erythropoietin (u-EPO) purified from urine of aplastic anemic patients were analyzed and compared with those for recombinant erythropoietin (r-EPO) prepared with baby hamster kidney (BHK) cells. Asparagine-linked neutral oligosaccharides were released from each EPO protein by N-oligosaccharide glycopeptidase (almond) digestion. The reducing ends of the oligosaccharide chains thus obtained were aminated with a fluorescent reagent, 2-aminopyridine, and the mixture of pyridylamino derivatives of the oligosaccharides was separated by high-performance liquid chromatography (HPLC) on an ODS silica column. More than 8 and 13 kinds of oligosaccharide fractions for u-EPO and r-EPO (BHK), respectively, were completely separated by the one-step HPLC procedure. The structure of each oligosaccharide thus isolated was analyzed by a combination of sequential exoglycosidase digestion and another kind of HPLC with an amide-silica column. Furthermore, high-resolution proton nuclear magnetic resonance (1H NMR) spectroscopy and methylation analyses were carried out in the case of r-EPO (BHK).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Sequence↗
PubMed1988

Further evidence for the presence of a thiazoline ring in the isoleucylcysteine dipeptide intermediate in bacitracin biosynthesis.

Isoleucylcysteine dipeptide, a first intermediate peptide in bacitracin biosynthesis, was liberated from the enzyme protein and oxidized with manganese dioxide in dimethylsulfoxide. The resulting oxidation product was identified by thin-layer chromatography as 2-(2-methyl-l-oxobutyl)-thiazole-4-carboxylic acid which has been isolated from the hydrolysate of bacitracin F. This result shows that the intermediate dipeptide contains a thiazoline ring, and that the thiazoline ring is synthesized at the dipeptide stage in the process of peptide chain elongation in bacitracin biosynthesis. Improbability of non-enzymatic dehydrative cyclization of the dipeptide is discussed.

Bacitracin↗
PubMed1988

A new method of three dimensional analysis of left ventricular wall motion.

The three dimensional (3D) shape of left ventricles (LV) was reconstructed from gated blood pool emission computed tomography (GECT) to assess regional LV wall motion. The 3D LV shape was created using LV boundaries detected by a threshold method. Based on the length from each LV boundary to the end diastolic LV center of mass, regional percent shortening and phase of the first harmonic by Fourier analysis were calculated to create 3D functional images. These images clearly demonstrated the 3D extent of wall motion abnormality. In addition, the same 3D analysis was applied to biplane X-ray left ventriculography (LVG) by assuming that LV short axis sections were elliptic. Results of planar imaging, 3D analysis of GECT, 3D analysis of LVG and conventional LVG findings correlated well with each other. The 3D analysis of GECT is useful for non invasive quantitative analysis of LV wall motion.

Adult↗
PubMed1988

Mechanics of percutaneous balloon valvotomy for mitral valvular stenosis.

The present study was performed to measure and calculate the mechanical force of percutaneous balloon valvotomy (PBV) for mitral valvular stenosis, using an equation pertaining to the mechanical force of the balloon needed to dilate the stenotic mitral valve. In case 1, the diameter of the mitral valve was enlarged by PBV from 1.43 cm to 2.40 cm and, in case 2, from 1.76 cm to 2.42 cm, with a mechanical force of 321 g and 436 g, respectively, following the equation.

Biomechanical Phenomena↗
PubMed1988

Water deprivation changes naloxone binding in the rat brain.

The significant relationship of drinking to brain opioid receptors was determined using naloxone, a preferential antagonist of opioid mu receptor, in water-deprived rats. Whereas 48-hour food deprivation did not affect naloxone binding in any brain regions, 48-hour water deprivation caused a significant decrease in naloxone binding in the striatum, but not in the other brain regions. The striatal naloxone binding was found to progressively decrease with a period (0-48 h) of water deprivation. No significant change in naloxone binding in the hypothalamus or midbrain was observed during water deprivation. Water deprivation did not change the affinity constant of naloxone binding in the striatum. These observations indicate that the change in the striatal opioid receptors was specifically associated with thirsty sensation in the rat.

Animals↗
PubMed1988

[A study of the cardiotocograms recorded by a separated 1MHz ultrasound transducer].

Fetal heart rate records were obtained in 12 antepartum and 13 intrapartum cases, with an ultrasonic Doppler transducer with five separated crystals and a conventional transducer. The loss of the FHR record due to increased noise in 30 minutes before delivery ranged from 1.1 to 23.2% (6.4 +/- 6.5%) in the separate type transducer, and it was 0.6 to 29.9% (10.5 +/- 7.6%) in the conventional one. During the 5 minutes before delivery, it was 3.3 to 58.0% (20.2 +/- 18.5%) in the separate type, and 3.3 to 70.0% (31.6 +/- 19.5%) in the conventional one. Clearer FHR records were obtained with the use of the separate type than the conventional one (p less than 0.05). Noise was mostly recorded in the 5 minutes before delivery. In the NST, the loss of the FHR record due to maternal posture change decreased when the new transducer (p less than 0.05) was used. The loss was 0 to 56.7% (14.9 +/- 18.2%) with the new type, and 2.0 to 100% (42.9 +/- 36.4%) with the conventional one for the maternal posture which showed the worst record. By using the separate type transducer, maternal posture need not to be limited in the NST, and the somatic and mental discomfort is less than when the conventional one is used.

Female↗