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Biomedical subjects

H Urabe

Publications and source records attributed to H Urabe.

At least 19 recordsLinked to original sources
PubMed2006

Factors related to renal dysfunction in patients with anorexia nervosa.

OBJECTIVE: Anorexia nervosa (AN) patients were surveyed to determine which disease factors were related to AN influenced renal dysfunction. METHODS: Data were from forty-five AN patients hospitalized in our department between 1995 and 2002. The patients were classified into three groups based on the type of anorexia: restricting (n=18), self-induced vomiting (n=13), and laxative abuse (n=14). Twenty-four hour-creatinine clearance (Ccr) was calculated within two weeks of hospitalization for comparison among the three groups. RESULTS: The Ccr level of the laxative abuse group was significantly lower than that of the restricting group (65.8+/-31.4 ml/min vs restricting type: 104+/-23.3 ml/min, p=0.002). The laxative abuse group had a significantly longer duration of illness than the restricting group (p<0.0001). Multiple regression analysis revealed the duration of illness to be a risk factor for renal function deterioration in AN patients (r=0.580, p<0.001). DISCUSSION: Renal function should be carefully followed during the treatment of AN patients with a long duration of illness, especially those with long-term laxative abuse.

Adolescent↗
PubMed2001

Asymmetric synthesis with a chiral catalyst generated from asymmetric autocatalysis.

A new and efficient one-pot system of asymmetric catalysis is presented in which a chiral catalyst (5-pyrimidyl alkanol) self-improves its ee by asymmetric autocatalysis and then acts as a highly enantioselective chiral catalyst for other asymmetric synthesis (addition of dialkylzincs to aldehydes) to provide products (sec-alcohols) with very high ee (up to 99%).[reaction: see text]

Journal Article↗
PubMed2001

The relationship between leachability of polymerization initiator and degree of conversion of visible light-cured resin.

Recently, polymerization-initiator-induced radicals have been identified as a biohazard as well as residual monomers. The present investigation was conducted to clarify the leaching behavior of the polymerization initiator and to measure the relationship between the leached amount of polymerization initiator and the degree of conversion of visible light (VL)-cured resin. Moreover, determining a suitable ratio of polymerization initiator to the base monomer according to the above relationship was carried out. The base monomer (UDMA/TEGDMA) was activated with varying concentrations of polymerization initiator (CQ/DMPT, CQ/DMAEMA) from 0.3-0.9 wt%, respectively, which were exposed to light for 40 s. Gas chromatograph mass spectrometry (GCMS) was carried out to evaluate the leached amount of polymerization initiator. The degree of conversion (DC) of the cured sample was estimated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. As the result, it was recognized that the leachability of the polymerization initiator (CQ, DMPT, and DMAEMA) depended on the degree of conversion of the VL-cured resin. Therefore, the optimal concentration of polymerization initiator can be determined from the relation between the degree of conversion and the leached amount of polymerization initiator, which is about 0.6 wt% for CQ/DMPT (1:1 in weight) and 0.5 wt% for CQ/DMAEMA (1:1 in weight) relative to the UDMA/TEGDMA (1:1 in weight) monomer.

Dental Cements↗
PubMed2000

A facile preparation of exo-cyclic conjugated dienes fused to lactams or lactones via intramolecular coupling of acetylenes and their behavior in Diels-Alder reactions.

[reaction: see text] Treatment of bis-acetylenic amides or esters 3 with (eta(2)-propene)Ti(O-i-Pr)(2) generates functionalized titanacyclopentadienes which, upon hydrolytic workup, give exo, exo-cyclic conjugated dienes 4 in good yields. Some regio- and stereochemical aspects of their Diels-Alder reaction with dienophiles are also disclosed.

Acetylene↗
PubMed2000

Generation of a silylethylene-titanium alkoxide complex. A versatile reagent for silylethylation and silylethylidenation of unsaturated compounds

(Trimethylsilyl)ethylene-titanium alkoxide complex (1) was generated from trimethyl(vinyl)silane, Ti(O-i-Pr)(4), and i-PrMgCl as a preformed alkene-titanium complex and reacted with several unsaturated compounds such as aldehyde, imine, other vinylsilane, and acetylene to give the corresponding coupling products 4a-f, 6, 8, and 10a-d in a regioselective manner. Both of the two carbon-titanium bonds of the complex 1 reacted successively with esters to afford silylcyclopropanols 11a-j, 13, and 15, some synthetic applications of which were illustrated in the preparation of beta-silyl ketones 16 and cyclopropenes 17. Asymmetric addition of 1 to a chiral acyloxazolidinone 19 gave optically active cyclopropanol (+)-11a of 50% ee.

Journal Article↗
PubMed1999

Effect of filler content and size to properties of composite resins on microwave curing.

The effect of filler content and size to property of composite resin using high purity spherical silica particles on microwave curing was examined by mechanical means and electron microscope observation to develop microwave-curing composite resin inlay. Increasing filler content in three kinds of filler particles (0.45, 0.96 and 1.46 microm) resulted in increasing compressive strength, diametral tensile strength and knoop hardness and indicated the highest values at the operative mixing limit. The effect of particle size was that the mechanical property of the 0.96 microm filled resin was highest, followed by 1.46 microm and 0.45 microm on the same filler content. The 0.96 microm filled resin had about the same knoop hardness on both surfaces of the cured sample, which means that uniform polymerization occurred in the cured sample. With electron microscope observation, the bubbles of about 1.0 microm and the cracks between the fillers and the matrix were observed in each cured resin. This is caused by the excessive absorption of microwave energy in fillers and surface treatment materials of fillers. Therefore, improvement of the composition of filler and surface treatment material of filler are needed, which makes it harder to absorb the microwave energy.

Journal Article↗
PubMed1999

Heterosexual transmission of GB virus C/hepatitis G virus infection to non-intravenous drug-using female prostitutes in Fukuoka, Japan.

To determine if GB virus C (GBV-C) or hepatitis G (HGV) infection can be transmitted by heterosexual intercourse, we tested serum samples from 234 non-drug-injecting female prostitutes for GBV-C/HGV. We used reverse transcription polymerase chain reaction to test for GBV-C/HGV RNA and ELISA for GBV-C/HGV-E2 antibody. The prevalence of total GBV-C/HGV marker (GBV-C/HGV RNA and/or GBV-C/HGV-E2 antibody) was 58/234 (24.8%) in the prostitutes, and 7/71 (8.9%) in matched controls. The GBV-C/HGV RNA and GBV-C/HGV-E2 antibody concurrence rate was 12.5% for the prostitutes, but was nil in matched controls. Total GBV-C/HGV marker was significantly higher in the prostitutes than in matched controls. Additionally, total GBV-C/HGV marker was associated with the number of years engaged in prostitution after adjusting for age. We found hepatitis B virus and hepatitis C virus infections in prostitutes to be associated with syphilis infection, but GBV-C/HGV infection was not. Thus, it seems likely that GBV-C/HGV can be transmitted by heterosexual intercourse, even in the absence of syphilis.

Adult↗
PubMed1999

Combinations of etchants, composite resins, and bracket systems: an important choice in orthodontic bonding procedures.

The objectives of this investigation were: (1) to compare the shear bond strengths (SBS) of metal, ceramic, and plastic brackets using different concentrations of maleic and phosphoric acid gels and aqueous solutions, and (2) to determine if a relationship exists between the type of acid etchant and the location of resin after debonding. A sample of 210 bovine incisors was divided among three different bracket groups (Victory series metal, Transcend 6000 ceramic, Spirit MB plastic). Prior to bonding, enamel was acid-etched using 37% phosphoric acid (H3PO4) gel and aqueous solution, 10% maleic acid gel and aqueous solution, 10% H3PO4 gel and aqueous solution, or 2% H3PO4 aqueous solution. SBS testing and the adhesive remnant index (ARI) score provided insight into the effects of the bonding process on enamel. Resin tags associated with each etchant type were inspected under scanning electron microscopy (SEM). Statistical analyses (level of significance, p = 0.05) of the data showed significant differences among groups. It was concluded that specific acid-composite-bracket combinations are recommended for use in clinical orthodontic practice in order to achieve efficient bonding.

Acid Etching, Dental↗
PubMed1999

Influence of polymerization initiator for base monomer on microwave curing of composite resin inlays.

Microwave polymerization was used to make composite resin inlays and the effect examined of the concentration of polymerization initiator for the base monomer. The monomers used were 2,2-bis [4-(3-methacriloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Bis-GMA and TEGDMA were mixed in a ratio of 6:4 by weight and were separated into five groups. To each group was added benzoyl peroxide (BPO) in the ratios of 0.1, 0.3, 0.5, 0.7 and 0.9 wt% as the polymerization initiator. These were used as the base monomers. The results showed that the degree of conversion of the cured sample increased with increasing concentration of BPO from 0.1 to 0.5 wt%, however there was no significant difference at 0.5, 0.7 and 0.9 wt% (P> 0.01). Compression strength, diametral tensile strength and the Knoop hardness showed a similar tendency as the degree of conversion. No significant difference was recorded in the Knoop hardness between the top and the bottom surfaces (P> 0.01), which suggested a uniform polymerization in the cured sample. Thus, microwave polymerization would be an efficacious method for making resin inlays with the addition of BPO to the base monomer (Bis-GMA:TEGDMA, 6:4). The maximum conversion was found at a concentration of 0.5 wt%.

Benzoyl Peroxide↗
PubMed1998

Putative protein serine/threonine kinase genes are located in several positions on the chromosome of Streptomyces coelicolor A3(2).

Seven DNA fragments containing putative protein serine/threonine kinase genes were cloned from Streptomyces coelicolor A3(2) by hybridization with a 165-bp amplified polymerase chain reaction product of pkaB containing kinase subdomains VI, VII and VIII. Among them, the nucleotide sequences of three fragments containing subdomains VI, VII and VIII were identical, while those of one fragment were identical with that of afsK, another protein serine/threonine kinase gene. However, these kinase-like genes with very similar nucleotide sequences were distributed on the chromosome of S. coelicolor A3(2).

Base Sequence↗
PubMed1998

Low-frequency Raman spectra of lysozyme crystals and oriented DNA films: dynamics of crystal water.

We observed low-frequency Raman spectra of tetragonal lysozyme crystals and DNA films, with varying water content of the samples. The spectra are fitted well by sums of relaxation modes and damped harmonic oscillators in the region from approximately 1 cm(-1) to 250 cm(-1). The relaxation modes are due to crystal water, and the distribution of relaxation times is determined. In wet samples, the relaxation time of a small part of the water molecules is a little longer than that of bulk water. The relaxation time of a considerable part of the crystal water, which belongs mainly to the secondary hydration shell, is an order of magnitude longer than that of bulk water. Furthermore, the relaxation time of some water molecules in the primary hydration shell of semidry samples is shorter than we expected. Thus we have shown that low-frequency Raman measurements combined with properly oriented samples can give specific information on the dynamics of hydration water in the ps range. On the other hand, we concluded, based on polarized Raman spectra of lysozyme crystals, that the damped oscillators correspond to essentially intramolecular vibrational modes.

Crystallization↗