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Biomedical subjects

I Uchida

Publications and source records attributed to I Uchida.

At least 91 records · Page 5Linked to original sources
PubMed1991

Trisomy 21: association between reduced recombination and nondisjunction.

To assess the association between recombination and nondisjunction of chromosome 21, we analyzed cytogenetic and DNA markers in 104 trisomy 21 individuals and their parents. Our DNA marker studies of parental origin were informative in 100 cases, with the overwhelming majority (94) being maternal in origin. This value is significantly higher than the 75%-80% maternal nondisjunction rate typically observed in cytogenetic studies of trisomy 21 and illustrates the increased accuracy of the molecular approach. Using the maternally derived cases and probing at 19 polymorphic sites on chromosome 21, we created a genetic map that spans most of the long arm of chromosome 21. The map was significantly shorter than the normal female linkage map, indicating that absence of pairing and/or recombination contributes to nondisjunction in a substantial proportion of cases of trisomy 21.

Adult↗
PubMed1990

Electron transferase activity of diaphorase (NADH: acceptor oxidoreductase) from Bacillus stearothermophilus.

Electrochemical kinetic measurements were carried out for electron-transfer between NADH and the oxidized forms of mediators (ferrocenylmethanol (FMA), ferrocenyl-1-ethanol (FEA), N,N,N',N'-tetramethylphenylenediamine (TMPD), Co(Phen)2+(3) and Fe(CN)4-(6)) catalyzed by diaphorase (NADH: acceptor oxidoreductase, EC 1.6.99.-) purified from Bacillus stearothermophilus. Cyclic voltammograms for the mediators with excess NADH in the presence of diaphorase gave steady-state currents. The quantitative analysis of the dependence of the current on the mediator concentration yielded a Michaelis constant (Km) and molecular activity (ko), which are difficult to determine by the conventional spectrophotometric method. Small Km and large ko values were observed for the oxidized forms of FMA, FEA and TMPD compared to those for Co(Phen)3+(3) and Fe(CN)3-(6). It is suggested that the reaction pocket of the present diaphorase is hydrophobic. The present electrochemical procedure for the determination of the kinetic parameters is applicable widely to similar enzyme reactions.

Amino Acids↗
PubMed1990

Nondisjunction of chromosome 21.

Chromosome heteromorphisms and restriction fragment length polymorphisms were used to study the origin of the extra chromosome in 54 trisomy 21 conceptuses. The parental origin was determined in 43 cases, with 39 (91%) being maternally and 4 (9%) parentally derived. Analysis of recombination demonstrated the presence of one or two cross-overs in most cases for which sufficient information was available, suggesting that failure to pair/exchange at meiosis I is relatively unimportant in the genesis of trisomy 21.

Adult↗
PubMed1990

Large exostosis of the mandibular coronoid process. Report of a case.

The clinical experience of a patient with a large exostosis who had a chief complaint of difficulty in opening the mouth is reported. Radiographic examinations, especially tomography and a CT scan, were useful in the diagnosis. Surgical removal is the treatment of choice. The lesion is usually approached by a combination of intraoral and buccal routes; we also employed such an approach in this particular case.

Adolescent↗
PubMed1990

WS-7528, a new isoflavanone with estrogen activity isolated from Streptomyces sp. No. 7528. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

WS-7528, produced by Streptomyces sp. No. 7528, was extracted from cultured broth, purified by solvent extraction followed by chromatography on silica gel and then isolated as pale yellow powder (C16H14O5, mp 95-98 degrees C). WS-7528 inhibited estrogen binding to its receptor protein in rat uterine cytosol. The IC50 value of WS-7528 for partially purified rat uterine cytosol receptor was 5.7 x 10(-8) M. This compound was found to induce the growth of the estrogen dependent cell line MCF-7. WS-7528 was tested orally and subcutaneously in immature rats to confirm its effect on the growth of the uterus. WS-7528 has also weak anti-inflammatory activity on the carrageenin paw edema of the rat model.

Animals↗
PubMed1989

Molecular characterization and protein analysis of the cap region, which is essential for encapsulation in Bacillus anthracis.

By using genetic complementation tests with various in vitro-constructed mutants with mutations in the cap region (which is essential for encapsulation in Bacillus anthracis), we identified three cistrons, capB, capC, and capA, in this order of arrangement. Minicell analysis revealed that these cistrons produce proteins of 44, 16, and 46 kilodaltons, respectively. The complete nucleotide sequence of 3,244 base pairs covering the whole cap region was determined and revealed the existence of the three open reading frames of capB (397 amino acid residues; molecular weight, 44,872), capC (149 amino acid residues; molecular weight, 16,522), and capA (411 amino acid residues; molecular weight, 46,420) arranged in the order predicted by complementation tests. These three cistrons were all transcribed in the same direction from promoters unique to each cistron. Judging from the predicted amino acid sequence of the three proteins and from their localization and their sensitivity to various physicochemical treatments, they appeared to be membrane-associated enzymes mediating the polymerization of D-glutamic acid via the membrane. Capsular peptides immunologically identical to that of B. anthracis were found in B. subtilis, B. megaterium, and B. licheniformis, but no sequence homologous to the cap region was found in any of these bacilli other than B. anthracis. Using strains of B. anthracis with or without insertional inactivation of the cap region, we found that the capsule of B. anthracis conferred strong resistance to phagocytosis upon the bacterial host.

Amino Acid Sequence↗
PubMed1989

FK409, a novel vasodilator isolated from the acid-treated fermentation broth of Streptomyces griseosporeus. III. Reaction mechanism and synthesis.

FK409 (1), a novel vasodilator, is a semi-artificial fermentation product of Streptomyces griseosporeus No. 16917, which was cultured in a medium containing nitrate. And the acid-treatment of the broth is essential for the generation of FK409. FK409 was considered to be formed via a novel synchronous nitrosation-nitration reaction of FR-900411 (2) which was produced by the strain as a precursor of FK409. The conversion of FK-900411 to FK409 proceeded under acidic conditions with nitrite formed by microbial reduction of nitrate. Total synthesis of FK409 was achieved starting from (E)-2-ethyl-2-butenal (3) via a nitrosation reaction of FR-900411 (2) as a key step.

Alkadienes↗
PubMed1989

[Ultrasonic detectability of multiple small hepatic nodules].

We analyzed the ultrasonic detectability of multiple daughter nodules accompanied by 18 hepatocellular carcinomas and multiple small nodules in 11 metastatic liver tumors identified by infusion hepatic angiography. In the cases of hepatocellular carcinoma, ultrasonic detectability of daughter nodules was remarkably limited. If any daughter nodules are detected by US, there is the great possibility that many other daughter nodules are undetected. However, US is effective in detecting small nodules in the metastatic liver tumor.

Carcinoma, Hepatocellular↗
PubMed1989

Effect of voluntary exercise on urinary excretion of catecholamines after traumatic shock in rats.

Thirteen rats were kept in cages equipped with running wheels for 10 months (exercise group), and 12 rats were kept in cages without running wheels during the same period (control group). Rats in both groups were subjected to a Noble-Collip drum trauma (40 rpm, 350 revolutions in total) after the 10-month conditioning period. Urine output, urinary epinephrine (E), and norepinephrine (NE) were measured until the seventh day after the trauma. Urine output decreased after the trauma in both groups to the same extent, but the recovery of urine output after trauma was accomplished faster in the exercise group than in the control group, and diuresis after trauma was seen only in the exercise group. Urinary E increased in both groups within 24 hours after trauma, but the increase in the exercise group was significantly less than in the control group. The amount of NE excreted depended somewhat on the urine volume, but there was no significant difference in changes in urinary NE after trauma between the groups. These results suggest that rats bred in an active condition suffered less severe traumatic shock accompanied by a reduced sympathoadrenal activity as compared with rats bred in a relatively sedentary condition.

Adrenal Glands↗
PubMed1988

Effect of epidural analgesia on postoperative insulin resistance as evaluated by insulin clamp technique.

The influence of epidural neural blockade on postoperative insulin resistance was studied using the euglycaemic insulin clamp technique. Eighteen patients undergoing elective upper abdominal surgery of moderate severity were allocated to two groups: group G patients underwent operation under general anaesthesia, and postoperative pain was relieved by systemic administration of analgesia; and group E patients received epidural analgesia during surgery and epidural morphine postoperatively. In each patient the euglycaemic insulin clamp test was performed twice: several days before surgery and on postoperative day 1. Peroperative catecholamine and cortisol responses were also measured to investigate possible endocrine mechanisms of the insulin resistance. Glucose disposal (M) decreased in both groups on postoperative day 1 at plasma insulin concentrations ranging from 1.2 to 10.0 milliunits ml-1, resulting in the downward shift of dose-response curves. However, this downward shift was significantly smaller in group E than in group G patients. Urinary adrenaline excretion increased markedly on the day of operation in group G, but was significantly inhibited in group E. Urinary noradrenaline excretion increased mainly on postoperative day 1 in group G, but was significantly inhibited in group E. Plasma cortisol response was lower in group E than in group G during and shortly after operation, and was significantly inhibited in group E on postoperative day 1. These results indicate that insulin resistance after elective abdominal surgery is due to a postreceptor deficit in glucose utilization, as indicated by the downward shift of the dose-response curves. This disturbance in glucose metabolism was reduced by epidural analgesia, the results being associated with inhibited catecholamine and cortisol responses.

Analgesics↗
PubMed1988

Cloning and CO2-dependent expression of the genetic region for encapsulation from Bacillus anthracis.

The capsule of Bacillus anthracis is an important virulence factor consisting of poly-D-glutamic acid. The genetic region required for the encapsulation was cloned in Escherichia coli from the capsule plasmid pTE702, using a selection procedure based on an immunodiffusion assay. The cloned region directed synthesis of the capsule both in E. coli and B. anthracis. Capsule synthesis from these clones, as in the wild type, was dependent upon the presence of CO2. However, encapsulation directed by the cloned fragment was less marked than from pTE702. Another region enhancing capsulation was shown to exist on pTE702. The minimum size of the encapsulation region was defined to within 2.7 kb DNA and shown to be essential for the encapsulation in B. anthracis.

Bacillus anthracis↗
PubMed1988

Vinigrol, a novel antihypertensive and platelet aggregation inhibitory agent produced by a fungus, Virgaria nigra. I. Taxonomy, fermentation, isolation, physicochemical and biological properties.

Vinigrol, produced by a fungal strain identified as Virgaria nigra, was extracted from the cultured mycelium, purified by solvent extraction followed by chromatography on silica gel and then isolated as crystals (C20H34O3, mp 108 degrees C). Vinigrol decreased arterial blood pressure of anesthetized normotensive rats dose-dependently when administered intravenously. Vinigrol inhibited platelet activating factor and epinephrine induced platelet aggregation.

Animals↗