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Biomedical subjects

M Ohtsuki

Publications and source records attributed to M Ohtsuki.

At least 91 records · Page 5Linked to original sources
PubMed1989

Solid phase synthesis of oligoribonucleotides using the 1-[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl (Ctmp) group for the protection of the 2'-hydroxy functions and the H-phosphonate approach.

The solid phase synthesis of oligoribonucleotides using the H-phosphonate approach and the 1-[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl (Ctmp) and dimethoxytrityl (DMTr) groups, respectively, for the protection of the 2'- and 5'-hydroxy functions is described. The use of a new reagent, tris-(1,1,1,3,3,3-hexafluoro-2-propyl) phosphite for the preparation of nucleoside H-phosphonate units is also discussed in detail.

Base Sequence↗
PubMed1989

[Clinical study on the prognosis of complete denture wearers covering 10 years. 3. Fitness test of the complete denture base].

The purpose of this study was to estimate the clinical condition of complete denture wearers. 72 patients came to our Dental Hospital according to our recall. The examination consisted of a questionnaire and clinical examinations. For objective evaluation, the fitness test of lower complete denture base was taken place and was classified into four groups by the thickness of the white-silicone film (A-zone 0-30 microns, B-zone 30-70 microns, C-zone 70-130 microns, D-zone 130 microns-). Results 1. The average ratio of four groups of the white-silicone film were A-zone 9.3%, B-zone 35.8%, C-zone 24.5% and D-zone 30.4%. 2. The fitness of anterior portion was ill fit in comparison with posterior portion. 3. There was statistically significant difference between the fitness of lower complete denture and dentist's judgment diagnosed as ill fit denture. 4. There was significant difference between the fitness test and the patients who complained about loose fit of the denture.

Denture Bases↗
PubMed1989

[Solvent power of new denture cleaner for denture calculus and the influence of this cleaner on the denture materials].

In order to chemically remove the calculus adhering to a denture, new denture cleaner was prepared on an experimental basis. The principal ingredient of this solution was a chilating agent which contained the phosphoric acid. This study consisted of the fundamental and the clinical examinations of this solution the purpose of which was to test the solvent power of this solution on the calculus and to evaluate its influence on the denture materials and its effectiveness in clinical practice. 1. the fundamental study 1) method (1) The test for the solvent power of this solution. The powder of tricalcium phosphate (T.C.P. powder: Wakohjunyaku Co.) was substituted for the calculus adhering to a denture. (1) The influence of the solution temperature on the solvent power. The T.C.P. powder was dissolved at 20 degrees C, 30 degrees C, 40 degrees C, 50 degrees C and 60 degrees C temperature in 10 g of the solution within 10 minutes and the amount of dissolved powder was weighted. The time was measured with a stop watch (Seiko Co.) until 0.5 g of T.C.P. powder had been dissolved in 10 g of the solution. (2) The effect of using it with an ultrasonic cleaner. The time to dissolve 0.1 g of T.C.P. powder in 10 g of this solution was compared with that of the 15% EDTA solution. The measurement was repeated 5 times and the arithmetic mean of the 5 sample values was calculated in order to show the experimental results. The room temperature was 19 +/- 2 degrees C, the humidity was 56 +/- 3%. (2) The influence of this solution on the denture materials. (1) resin specimen. In order to test the transverse strength, transverse deflection, Young's modulus and Knoop hardness, resin specimens were processed in the manner specified in I.S.O. 1567. The data were compared the resin specimens steeped in this solution and with the control sample that was steeped in water. The specimens were immersed up to 24 hours. Furthermore the existence of tarnish was observed with a 40 times microscope. (2) metal specimen. In order to test the corrosion, metal specimens were produced according to the manner of a corrosion test. The metal specimens were held vertically and the end immersed to 20 mm in this solution for 24 hours and 120 hours each. After steeping, each specimen was measured for loss in weight. The data were calculated as the loss in weight per hour (mg/cm) and the depth of corrosion per year (mm/yr).(ABSTRACT TRUNCATED AT 400 WORDS)

Corrosion↗
PubMed1989

[Cellular immunoregulation in atopic dermatitis--hyperresponsiveness to interleukin-4 and hyporesponsiveness to interleukin-2].

We examined the responsiveness to Interleukin-4 (IL-4) and Interleukin-2 (IL-2) of peripheral blood lymphocytes from patients with atopic dermatitis (AD) and non-AD controls. The IL-4 responsiveness of the AD patients was found to be higher than that of the non-AD controls. In contrast, the IL-2 responsiveness of the AD patients was relatively lower than that of the non-AD controls. When IL-4/IL-2 responsiveness ratio was compared, the IL-4/IL-2 responsiveness ratio of the AD patients (54.1 +/- 18.5) was significantly higher than that of the non-AD controls (24.8 +/- 9.9, p less than 0.001). The high IL-4/IL-2 responsiveness ratio found in the AD patients may possibly be related to the pathogenesis of AD.

Adolescent↗
PubMed1986

Transcription factor(s) of Ehrlich ascites tumor cells having affinity to the 'TATA' box and a further upstream region of the adenovirus 2 major late gene.

A fraction containing a transcription factor(s) of RNA polymerase II was prepared from a nuclear lysate of Ehrlich ascites tumor cells and its binding to a promoter region of the adenovirus 2 major late gene was examined. Results showed that this fraction contained a factor(s) binding to two distinct regions: a region including the 'TATA' box and another region further upstream. The upstream protected region was different from that reported to be protected by a HeLa cell factor, suggesting species specificity of transcription factor(s) in DNA binding.

Adenoviruses, Human↗
PubMed1986

In vitro transcription of a chromatin-like complex of major core protein VII and DNA of adenovirus serotype 2.

Major core protein VII of adenovirus serotype 2 (Ad2) is thought to play a role as a histone octamer in eukaryotic cells. We compared the template activity of the VII-DNA complex formed in vitro with that of protein-free DNA. Hybridization assay of in vitro transcripts showed that transcription from regions located in the middle of Ad2 DNA decreased when Ad2 DNA formed a complex with VII. This suggests that the chromatin structure plays a role in regulation of transcription of the adenovirus genome.

Adenoviridae↗
PubMed1984

Effect of the DNA-binding domain of poly(ADP-ribose)synthetase on accurate transcription initiation in a HeLa cell lysate.

The effect of papain-digested fragments of poly(ADP-ribose)synthetase on accurate transcription initiation by RNA polymerase II was studied using a HeLa cell lysate. It was found that the DNA-binding domain of the enzyme, like the intact enzyme, preferentially suppressed random transcription initiation, whereas the automodification domain had no effect on transcription.

DNA↗
PubMed1984

Assessment of morphology of asymmetrical biological macromolecules with digital techniques.

Digital image processing techniques which determine the morphology of an unordered, spherical biological macromolecule are discussed. The techniques involve slicing appropriate intensity levels of the scanning transmission electron microscope image so that more accurate observation of morphology can be made. The techniques were applied to native and hybrid canine plasma high-density lipoprotein molecules. Resulting data indicated that the techniques were very useful to assess the diameters of both molecule and surface substructures of such asymmetrical macromolecules.

Analog-Digital Conversion↗
PubMed1984

Accurate transcription initiation in an Ehrlich ascites tumor cell lysate.

An in vitro system for accurate transcription initiation by RNA polymerase II was developed using Ehrlich ascites tumor cells. Truncated DNA containing adenovirus 2 major late promoter was faithfully transcribed in this lysate, although the efficiency of transcription was lower than that in a HeLa cell lysate. Creatinephosphate greatly enhanced accurate transcription in this lysate. The transcriptions of various truncated mouse genes containing promoter regions in this lysate were tested, but the syntheses of run-off products were not clearly detected. Adenovirus 2 major late promoter was utilized more efficiently when integrated into circular plasmid DNA than when integrated into truncated DNA, as shown by S1 nuclease analysis.

Animals↗
PubMed1983

Evidence for a central substructure in a Lumbricus terrestris hemoglobin obtained with STEM low-dose and digital processing techniques.

Applications of scanning transmission electron microscope (STEM) low-dose and digital image processing techniques to the annelid extracellular hemoglobin of Lumbricus terrestris have shown the existence of a central substructure. The techniques involve low-dose STEM images of less than 2 e/A2 irradiation. Many such low-dose images were then aligned in their symmetry, N-fold averaged, and summed. The central substructure appears to be supported by spokes which are connected to a surrounding hexagonal bilayer of 12 subunits. In comparison to the summed image of Nephtys hombergii hemoglobin which is known to possess a central substructure, the morphology of both central mass and spokes were very similar. This finding of a central substructure is consistent with the report of a small angle X-ray scattering study (Pilz et al., 1980, Int. J. Biol. Macromol. 2, 279-283) which predicted the possible existence of substructure in the center of the molecule.

Animals↗
PubMed1983

Ultrasonographical diagnosis of fatty liver: significance of the liver-kidney contrast.

In order to investigate the reliability of ultrasonography in the diagnosis of fatty liver, retrospective evaluation was made of abdominal echograms in 45 patients with various diffuse liver diseases who underwent liver biopsy within 2 weeks after the ultrasound study. Instead of the well-recognized but subjective diagnostic criterion, i.e. the bright liver pattern, liver-kidney contrast is proposed as a new criterion. The liver-kidney contrast is based on the brightness of the liver in comparison to the renal parenchyma where fatty change seldom occurs. Combination of this liver-kidney contrast with two other well-known ultrasonographical findings of fatty liver, vascular blurring and deep attenuation, enables us to grade fatty change semiquantitatively. When fatty change of over 30% in the hepatic lobule was adopted as the definition of fatty liver, the satisfaction of both liver-kidney contrast and vascular blurring presented an ultrasound diagnostic criterion for fatty liver, with sensitivity of 83%, specificity of 100%, and an accuracy of 96%.

Abdominal Muscles↗
PubMed1983

A case of idiopathic fatty liver detectable only by ultrasonography.

A 40-year-old man was diagnosed as fatty liver according to our ultrasonographical criteria for fatty liver, i.e., liver-kidney contrast in the ultrasound mass screening of the liver, biliary tract and pancreas. He lacked any signs or symptoms, nor any known causes of fatty liver, i.e., obesity, diabetes, hyperlipidemia, ingestion of alcohol or drugs. Liver biopsy of this patient revealed fatty change of about 50% of the hepatic lobules. It has been difficult to suspect the presence of latent fatty liver which lacked both the abnormality in the liver function test and hepatomegaly, and even impossible when it lacked any risk factors. In the future as the ultrasonography becomes more generally used as a primary screening examination, "idiopathic latent fatty liver", like this patient, will be more frequently found and this, in turn, will contribute to the progress of the epidemiology and etiology of fatty liver.

Adult↗