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Biomedical subjects

Y Sumi

Publications and source records attributed to Y Sumi.

At least 91 records · Page 5Linked to original sources
PubMed1998

Histochemical staining of chromium with 2-(8-quinolylazo)-4,5-di-p-tolylimidazole.

A new highly sensitive staining agent for chromium (Cr) has been introduced. This staining agent, 2-(8-quinolylazo)-4,5-di-p-tolylimidazole (QTI), was found to be more than ten times as sensitive for Cr than the conventional staining agent, Chromazurol S, and QTI also stained cadmium, copper, lead and zinc. Differentiation between the staining of Cr and other metals was achieved by immersing the tissue sections in dilute alkylamine solutions before they were stained with QTI. Thus, it was possible to selectively stain for Cr by blocking other metals.

Animals↗
PubMed1998

[Procainamide-induced lupus in a patient with bilateral pleural effusion].

A 70-year-old physician was admitted to our hospital because of bilateral pleural effusion and left-sided chest pain on deep inspiration. On admission, the APTT was prolonged and was not corrected with a 1:1 mixture of normal plasma. Results of serological examinations included a positive lupus-anticoagulant test and a positive ANA test at a titer of 1:1,280 in a homogeneous pattern. The patient's age, sex, symptoms, signs, and laboratory results all argued against the diagnosis of SLE except for ANA and lupus anticoagulant test. Because procainamide had been prescribed (250 mg every 6 h) for premature ventricular contractions for eight years before admission, procainamide-induced lupus was suspected. Procainamide was discontinued. Chest pain persisted and tests for c-reactive protein were positive. Prednisolone was administered. Procainamide induced lupus was diagnosed, because anti-histone H 2 A-H 2 B complex antibodies were high by enzyme-linked immunosorbent assay, and IgM-class anti-histone antibodies were found in response to H1, H 2 B and H 2 A-H 2 B complex (immunoblotting), which suggested the drug induced lupus. There are only a few reports of drug induced lupus in which the lupus-anticoagulant test was positive and prednisolone was indicated. The measurements of anti-histone antibodies and of expression of anti-histone antibodies were useful in distinguishing drug-induced lupus from SLE.

Aged↗
PubMed1997

Detection of melatonin and serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase activities in rat ovary.

Melatonin (N-acetyl-5-methoxytryptamine) and the activities of two melatonin-synthesizing enzymes, serotonin N-acetyltransferase (acetyl coenzyme A: arylalkylamine N-acetyltransferase EC 2.3.1.87; NAT) and hydroxyindole-O-methyltransferase (S-adenosyl-L-methionine: N-acetylserotonin-O-methyltransferase EC 2.1.1.4; HIOMT), were assayed in extracts of ovaries obtained from virgin Wistar-derived rats (7-9 week-old) during the light period of a 12 h light/12 h dark cycle. Melatonin was detected in the rat ovary using reverse-phase high-performance liquid chromatography (HPLC) coupled with fluorometric detection and radioimmunoassay (RIA). In addition, NAT and HIOMT activities were found in rat ovary. The apparent Michaelis constants (Km) for the substrates of NAT and HIOMT in the rat ovary were similar to those reported for the pineal gland and retina. These data suggest that the rat ovary, like the pineal gland and the retina, may synthesize melatonin from serotonin by the sequential action of NAT and HIOMT.

Acetylserotonin O-Methyltransferase↗
PubMed1997

Hydroxyindole-O-methyltransferase activity in the silkworm (Bombyx mori).

Hydroxyindole-O-methyltransferase (HIOMT; EC 2.1.1.4) catalyzes the final step in the melatonin (N-acetyl-5-methoxytryptamine) biosynthetic pathway. HIOMT-like activity was detected in the head of fifth last-instar larvae of the silkworm (Bombyx mori), and the optimum pH for this activity was 7.9. The apparent Michaelis constants (K(m)) for S-adenosyl-L-methionine and N-acetylserotonin were 87.6 microM and 96.6 microM, respectively. When the silkworms were entrained to a 12 h light/12 h dark lighting schedule, the HIOMT-like activity showed a significant diurnal variation with high levels during the dark period. The diurnal variation in the activity persisted in constant darkness, but was suppressed by constant light. These findings demonstrate that HIOMT-like activity in the silkworm head occurs as a circadian rhythm and that the rhythm entrains to environmental light/dark cycles. The melatonin rhythm in the silkworm head may therefore be regulated not only by serotonin N-acetyltransferase (EC 2.3.1.87), but also by HIOMT.

Acetylserotonin O-Methyltransferase↗
PubMed1997

Effect of ethanol pretreatment on mercury distribution in organs of fetal guinea pigs following in utero exposure to mercury vapor.

Ethanol (Et-OH), which is an inhibitor of catalase, reduces oxidation of mercury vapor (Hg0) into ionic mercury (Hg2+). Consequently, exposure of pregnant animals to Hg0 with pretreatment of Et-OH causes penetration of larger amount of Hg0 to the fetus. The fate of Hg0 in the fetus of pregnant guinea pigs, thus penetrated, was investigated. Et-OH pretreatment of the dams resulted in the transfer of more mercury to the fetuses and led to a marked increase in mercury in the fetal liver. Furthermore, according to the mercury distribution in the fetal organs, the animals in the Et-OH-pretreated group fell into two subgroups: a group of fetuses (subgroup 1) had higher mercury concentrations in the brain, heart and kidney compared with the group which was exposed to Hg0 without Et-OH-pretreatment (Hg0 group) and another group (subgroup 2) with similar organ mercury concentrations to that of the Hg0 group. Determination of metallothionein (MT) concentrations showed that MT concentration in the fetal liver of subgroup 2 was significantly higher than that of subgroup 1 and the Hg0 group. Further, the Sephadex G-75 chromatography of the cytosol of the fetal liver in subgroup 2 revealed that most of mercury, about 66%, was bound to metallothionein-like protein. On the other hand, in the cytosol of fetal liver of subgroup 1, a small amount, about 10% appeared in fractions corresponding to MT. These findings suggest that fetal hepatic MT plays a significant defense role against mercury crossing the placenta and is involved in regulating for the mercury distribution in the fetus.

Administration, Inhalation↗
PubMed1997

Hydroxyindole-O-methyltransferase activity assay using high-performance liquid chromatography with fluorometric detection: determination of melatonin enzymatically formed from N-acetylserotonin and S-adenosyl-L-methionine.

A reliable, sensitive and rapid assay has been developed for determining the activity of hydroxyindole-O-methyltransferase (HIOMT; S-adenosyl-L-methionine:N-acetylserotonin-O-methyltransferase; EC 2.1.1.4), which catalyzes the final step in the melatonin (N-acetyl-5-methoxytryptamine) biosynthetic pathway. This method is based on the separation and detection of melatonin formed enzymatically from N-acetylserotonin and S-adenosyl-L-methionine, by high-performance liquid chromatography with fluorometric detection. The detection limit for melatonin formed per sample was as low as 150 fmol, indicating that the sensitivity of this assay was comparable to that of a radioisotopic assay. The assay was applied to the determination of HIOMT activity in rat pineal gland. The HIOMT activity obtained in this study was comparable with, or slightly lower than those reported previously using radioisotopic assays.

Acetylserotonin O-Methyltransferase↗
PubMed1997

Titanium-inlay--a new root-end filling material.

To obtain better results following periradicular surgery, we have developed a Titanium-Inlay with SuperEBA cement as a sealer as a new root-end filling material. This was combined with an ultrasonic root-end preparation technique. The preliminary results suggest that the surgical method we adopted is simple and the results are predictable. The material and technique are presented in this article.

Biocompatible Materials↗
PubMed1997

[A case of esophageal leiomyoma found as mediastinal tumor, diagnosed with endoscopic ultrasonography].

A 20 year-old female was admitted to our department because of an abnormal shadow in chest roentgenogram on a physical check-up. The barium swallowing study revealed an oppression of the middle of the esophagus. Endoscopy, chest CT and MRI failed to distinguish submucosal tumor from mediastinal tumor. Endoscopic ultrasonography showed the mass originated from the esophagus and a diagnosis of esophageal smooth muscle tumor was obtained. The tumor was tried to resect by thoracoscopic surgery but was failed because of its shape like a tortoise shell. The tumor was resected through the right thoracotomy and the diagnosis was confirmed histopathologically.

Adult↗
PubMed1997

Influence of the discontinuation of a school-based, supervised fluoride mouthrinsing programme on the prevalence of dental caries.

OBJECTIVE: Since 1984 a weekly supervised fluoride mouthrinsing programme has been implemented for schoolchildren in Hisayama, Japan. Consequently, four years after the start of the programme the DMFT index for 12.5-year-old schoolchildren in Hisayama decreased to a value of less than 3.0. However, since 1992 it has increased. The purpose of this study was to investigate the causes of this increasing prevalence of dental caries since 1992. PARTICIPANTS: One hundred and one schoolchildren aged 12 years in 1994 were selected. This age group showed the highest increase in the prevalence of dental caries in that year. OUTCOME MEASURES: Children who had discontinued the use of fluoride mouthrinse for one year or more were identified by means of a confidential questionnaire. Oral examination was carried out, by three examiners, under a suitable artificial light using a mirror and an explorer. RESULTS: The DMFT and DMFS indices of the continuous mouthrinsing (CM) group were significantly lower than those of the discontinuous mouthrinsing (DM) group (P < 0.001). Significant differences between the CM and DM groups were also observed in the DMFT rates for premolars (P < 0.05) and for the first molar (P < 0.001). CONCLUSIONS: The continuation of fluoride mouthrinsing for children of school age was important in achieving the advantages of the programme in Hisayama.

Bicuspid↗
PubMed1996

Selective Isolation of DNA or RNA Using Single-Stranded DNA Affinity Latex Particles.

We developed latex particles with a diameter of about 0.22 µm on which single-stranded (ss) DNA was covalently coupled to select or enrich its complementary DNA or mRNA. DNA was first covalently coupled to the latex particles in the double-stranded (ds) form with both blunt and protruding ends. More than 80% of the dsDNA was coupled through the ssDNA stretch at its protruding end. The presence of NaCl in the immobilization reaction severely inhibited DNA from coupling to the particles. The particles were then treated with alkali or heated to denature the dsDNA and sedimented by a brief centrifugation to yield ssDNA immobilized particles. They allowed the selective and efficient isolation of a desired RNA from total cellular RNA.

Journal Article↗
PubMed1996

Histochemical staining of cadmium with 2-(8-quinolylazo)-4,5-diphenylimidazole.

In order to develop a stain with increased sensitivity and selectivity for cadmium (Cd), we synthesized and characterized 2-(8-quinolylazo)-4,5-diphenylimidazole (QAI). This chelating agent was more than twice as sensitive for Cd than the best conventional staining agents, including benzothiazolylazo-beta-naphthol. Differentiation between Cd and zinc (Zn) was achieved by immersing tissue sections in TRIS(2-aminoethyl)amine before they were stained with QAI. This pretreatment made it possible to selectively stain for Cd by blocking Zn.

Animals↗
PubMed1996

Ultrasonic root-end preparation: clinical and radiographic evaluation of results.

PURPOSE: This study evaluated the results of periradicular surgery performed using ultrasonic root-end preparation. PATIENTS AND METHODS: The course of healing during observation periods ranging from 6 months to 3 years was examined in 157 teeth. RESULTS: One hundred forty-five teeth were successfully treated, for a success rate of 92.4%. CONCLUSION: It was concluded that the ultrasonic root-end preparation technique for periradicular surgery is a simple procedure that provides excellent results.

Adolescent↗
PubMed1996

Purification and substrate specificity of an endo-beta-N-acetylglucosaminidase from pea (Pisum sativum) seeds.

An endo-beta-N-acetylglucosaminidase was purified to homogeneity from the seeds of pea (Pisum sativum). The molecular mass of the purified enzyme was estimated to be 41,669 Da by MALDI-TOF MS analysis and its isoelectric point to be 4.3 by isoelectric focusing. The enzyme was stable at pH 4-7 and at 25-50 degrees C, and had the highest activity toward Man6GlcNAc2-PA at pH around 7.0. Oligomannose type sugar chains (Man9-6GlcNAc2-PA) and a hybrid type sugar chain (GlcNAc1Man5GlcNAc2-PA) were most favored substrates followed by Man5GlcNAc2-PA, Man3GlcNAc2-PA, and GlcNAc2Man3GlcNAc2-PA, but xylose-containing sugar chains (Man4-3Xyl1GlcNAc2-PA and Man3Fuc1Xyl1GlcNAc2-PA) or a biantennary complex type sugar chain (Gal2GlcNAc2Man3GlcNAc2-PA) could not be hydrolyzed by the enzyme. The Km values of the enzyme for Man5GlcNAc2-PA, Man6GlcNAc2-PA, and Man9GlcNAc2-PA were 0.40 mM, 0.25 mM, and 0.32 mM, respectively.

Base Sequence↗
PubMed1995

Melatonin and arylalkylamine N-acetyltransferase activity in the silkworm, Bombyx mori.

Melatonin (N-acetyl-5-methoxytryptamine) was identified in the head and hemolymph of the silkworm, Bombyx mori, using reversed-phase high-performance liquid chromatography coupled with fluorometric detection and radioimmunoassay. In addition, evidence of arylakylamine (serotonin) N-acetyltransferase (NAT) a key enzyme controlling the synthesis of melatonin in vertebrates, was found in the head of the silkworm. Melatonin levels in the head and hemolymph and the NAT activity in the head were significantly higher during the dark period than during the light period of a 12-h light/12-h dark cycle. The day-night changes persisted in constant darkness but were suppressed by constant light. The results suggest that the synthesis and release of melatonin in the silkworm head occur as a circadian rhythm that is entrained by environmental light/dark cycles, as it is in the pineal gland of vertebrates. Melatonin in the silkworm head may function as a neurochemical mediator of photoperiodic control of developmental events such as molting, eclosion and diapause.

Animals↗
PubMed1995

Construction of a cDNA library for a specific region of a chromosome using a novel cDNA selection method utilizing latex particles.

A novel method is described for the rapid concentration of particular cDNAs and their mapping to specific regions of a genome. The strategy for 'cDNA scanning' is based on the hybridization of an entire library of cDNAs to a large fragment of genomic DNA that is covalently bound to latex particles. The hybridized cDNAs are eluted, amplified by PCR and cloned into a lambda vector. Selected cDNAs that hybridized to the genomic DNA are cloned, with subsequent sequence analysis. Region-specific DNA fragments prepared from a yeast artificial chromosome (YAC) clone, EG10D9, which maps to chromosome 5 of the small cruciferous plant Arabidopsis thaliana (At), were used to prepare a model system and were covalently bound to latex particles. cDNAs that hybridized to EG10D9 were concentrated by hybridization to the immobilized DNA. The hybridized cDNAs were recovered and amplified by PCR. The resultant sub-library of cDNAs of 0.5-2 kb in length was enriched about 1000-fold. The partial sequences of the cDNAs provided information about genes that are located on the EG10D9 region of the At genome. The cDNA scanning strategy provides an efficient method for the mapping of expressed genes which could be used as expressed sequence tags (EST) within a genome.

Arabidopsis↗