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Biomedical subjects

Y Toda

Publications and source records attributed to Y Toda.

At least 91 records · Page 5Linked to original sources
PubMed1993

Further isolation of glycosides from Cynanchum hancockianum.

Three new glycosides, neohancosides B, C, and D, have been isolated as polyacetates 2, 3, and 4 from Cynanchum hancockianum along with neohancoside A hexaacetate [1]. The new compounds were established as 9-hydroxylinalool-3-O-beta-D-xylopyranosyl-(1-->6)-beta-D-glucopyr anoside heptaacetate [2], 2-hydroxyacetophenone-2-O-beta-D-xylopyranosyl-(1-->6)-beta-D-gluc opyranoside hexaacetate [3], and 6'-O-sinapoylsucrose octaacetate [4] by means of spectroscopic and chemical tools.

Drugs, Chinese Herbal↗
PubMed1993

Brief physical inactivity prolongs colonic transit time in elderly active men.

The effects of two weeks of reduced activity on gastrointestinal transit time were studied in nine healthy elderly subjects, who had engaged in regular recreational exercise for ten years. Physical inactivity was achieved by a restriction of all kinds of physical exercise and by staying at home. Mouth-to-cecum transit time was measured by a breath hydrogen method and mean total and segmental colonic transit times by a radiopaque marker method. The mouth-to-cecum transit time did not change during the period of physical inactivity. The mean total colonic transit time (10.9 +/- 2.7 h) was significantly prolonged to 19.5 +/- 2.9 hours during the physical inactivity (p < 0.01). This prolongation was due to slowed transit through the right and the left segments of the colon. The transit time of the rectosigmoid segment of the colon was not affected. In conclusion, the period of physical inactivity prolonged the colonic transit time in active elderly subjects.

Aged↗
PubMed1992

Immunoelectron microscopic studies of glycosaminoglycans in the metaphyseal bone trabeculae of growing rats.

The types and distribution of glycosaminoglycans (GAGs) were studied immunocytochemically in osteoid, mineralized bone matrix, and cartilage matrix of growing rat metaphyseal bone after aldehyde fixation and EDTA demineralization, using four monoclonal antibodies (mAbs 1-B-5, 2-B-6, 3-B-3 and 5-D-4). These mAbs specifically recognize epitopes in non-sulphated chondroitin (C0-S); chondroitin 4-sulphate (C4-S) and dermatan sulphate (DS); chondroitin 6-sulphate (C6-S) and C0-S; and keratan sulphate (KS) respectively. In osteoid, all mAbs except 1-B-5 weakly stained matrix material on and between collagen fibrils, and moderately stained organic material corresponding to bone nodules, which are known sites of mineralization. However, the staining of osteoid abruptly decreased at the mineralization front; weak staining was confined mostly to the organic material of bone nodules in mineralized bone matrix, with very weak or no staining of the rest of the bone matrix. This staining progressively decreased toward the mineralized cartilage matrix and became negative. The mineralized cartilage matrix and lamina limitans reacted strongly with all mAbs except 5-D-4. These results indicate that osteoid contains sulphated proteoglycans containing C4-S and/or DS, C6-S and KS, and subsequent bone matrix mineralization appears to require accumulation of these macromolecules within bone nodules and eventual loss of these substances for complete mineralization, whereas proteoglycans containing C0-S, C4-S and/or DS, and C6-S still exist in mineralized cartilage matrix and lamina limitans.

Animals↗
PubMed1992

Structural determination of gangliosides that bind to influenza A, B, and C viruses by an improved binding assay: strain-specific receptor epitopes in sialo-sugar chains.

An improved binding assay for detection of ganglioside receptors for influenza A, B, and C viruses was developed. In this system, the virions bound to gangliosides that were developed on a silica gel thin-layer plate were detected by mouse monoclonal antibody against viral hemagglutinin and peroxidase-conjugated anti-mouse immunoglobin. No hydrolysis of the gangliosides by viral receptor-destroying enzyme was detected in the present condition. The reactivity of the viruses to gangliosides depended on the amount of developed gangliosides (10 pmols-10 nmols), the molecular species of sialic acid, and their sugar sequences. Human influenza A (PR/8/34), B (Lee/40), and C (Ann Arbor/1/50) viruses bound different receptor epitopes of sialo-sugar chains of gangliosides. The A/PR/8 virus bound most effectively to Neu5Ac-containing lacto-series gangliosides carrying type I and type II sugar chains, followed by ganglio-series and hematoside-series gangliosides. The A/PR/8 virus weakly bound to Neu5Ac alpha 2,6lactotetraosylceramide [IV6(Neu5Ac)Lc4Cer] and Neu5Ac alpha 2,6paragloboside [IV6(Neu5Ac)nLc4Cer] carrying Neu5Ac alpha 2,6Gal sequence, although their Neu5Ac alpha 2,3Gal derivatives were the most potent gangliosides tested. B/Lee/40 bound restrictively to IV6(Neu5Ac)Lc4Cer and IV6(Neu5Ac)nLc4Cer, which carry Neu5Ac alpha 2,6Gal sequence, and type I and type II lacto-series sugar chain, respectively. C/Ann Arbor/1/50 reacted only with 9-O-Ac-Neu5Ac-carrying sugar chains in all the gangliosides tested. This method also allowed the microanalysis of receptor gangliosides of unknown samples. ESK cells, sensitive to the influenza A viruses infection, expressed several kinds of receptor active gangliosides, while those from ESK-R cells, resistant to the virus infection, were undetectable.

Binding Sites↗
PubMed1992

Siblings of 21-hydroxylase deficiency (non-salt-losing) with aldosterone hypersecretion.

We describe siblings with the non-salt-losing form of 21-hydroxylase deficiency who had hypersecretion of aldosterone and plasma renin activity (PRA). Blood pressure and serum electrolytes in both cases were normal despite the aldosterone hypersecretion. Aldosterone secretion was elevated markedly with ACTH administration and with sodium deprivation and/or volume depletion during ACTH suppression by dexamethasone. With suppression by dexamethasone, aldosterone hypersecretion was decreased with lowering of the steroids proximal to the block in the biosynthetic pathway. However, urinary sodium excretion was decreased. These results suggest that the biosynthetic pathway for aldosterone production was preserved. Furthermore, aldosterone hypersecretion and high PRA may serve to compensate for the sodium loss which results in turn from the overproduction of the sodium-losing steroids, such as progesterone and 17 alpha-hydroxyprogesterone which are aldosterone antagonists.

Adolescent↗
PubMed1992

Studies on viridenomycin, a novel 24-membered macrocyclic polyene lactam antibiotic.

A new antitumor antibiotic, designated AL081, was obtained from the culture filtrate of an actinomycete identified as Streptomyces gannmycicus, and found to be identical with viridenomycin by direct comparison. The structure of the antibiotic was determined by NMR spectral analysis including a variety of two-dimensional techniques to be a novel 24-membered macrocyclic polyene lactam. Viridenomycin prolonged the survival periods of mice bearing P388 leukemia and B16 melanoma cells.

Animals↗
PubMed1992

[The effect of anesthetic agents on descending spinal cord evoked potential and the compound muscle action potentials elicited by stimulation at the cerebral motor cortex and the spinal cord].

Recently, intraoperative monitoring of the motor tract by descending spinal cord motor evoked potentials (MEP) and compound muscle action potentials (CMAP) has been applied in clinical testing. Since several reports have mentioned the vulnerability of these potentials to anesthetic agents, experimental studies were carried out on the relationship between these potentials and anesthesia using 41 adult cats. The effects of anesthesia on changes in amplitude of the direct wave (D wave) and indirect wave (I wave) of the MEP and CMAPs were investigated. These potentials were generated by stimulation of the spinal cord and the motor cortex, respectively. Enflurane (2%), halothane (1%) and isoflurane (1.5%) with pure oxygen decreased the amplitude of the I wave to less than 50% of the control level. The CMAP after stimulation of the spinal cord was degraded to less than 30%, and the CMAP after cortical stimulation vanished completely. Only the D wave was stable against inhalational anesthetic agents. Sixty-seven percent nitrous oxide with the above concentrations of these inhalational anesthetic agents decreased the amplitude of the I wave to less than 30% and the CMAP evoked by spinal cord stimulation vanished. The effect of modified NLA (diazepam and pentazocine) on these potentials was weaker than that of the inhalational anesthetic agents.

Action Potentials↗
PubMed1991

Impairment of bone formation with aluminum and ferric nitrilotriacetate complexes.

The deleterious effects of aluminum(AL) and iron(Fe) on bone formation were studied in the presence of nitrilotriacetate (NTA) as a chelator. Both Al-NTA (1.0-1.5 mg Al/kg/day, n = 12)- and ferric nitrilotriacetate (Fe-NTA) (2.0 mg/kg/day, n = 4)-treated Wistar rats showed renal insufficiency blood urea nitrogen [BUN] levels of 25 +/- 8.8-20 +/- 0.7 compared to 12 +/- 0.7-11 +/- 0.4 mg/dl), osteomalacia with a relative osteoid volume of 31.5 +/- 5.6-13.2 +/- 2.4 compared to 4.6 +/- 1.8-0.83 +/- 0.12%, and bone growth retardation (3.1 +/- 0-3.0 +/- 0.2 compared to 3.4 +/- 0-3.3 +/- 0.1 cm) in 24 control rats. Dietary vitamin E(VE) supplementation prevented the Fe-NTA-induced impairment, but not the Al-NTA toxicity. Aluminum was deposited at the interface between osteoid and mineralized bone, while Fe was deposited in the osteoblasts and osteoclasts. There seems to be a positive correlation between hypophosphatemia and osteomalacia but carboxy-terminal parathyroid hormone (C-PTH) and calcium (Ca) levels in the serum were not related to the degree of osteomalacia. Administration of Al-NTA results in more bone Al deposition than that of aluminum chloride (AlCl3) (450 +/- 40 compared to 211 +/- 18 mg/kg fat-free dry weight). The Fe-NTA bone change is related to VE-preventable cellular injury, being consistent with the notion that Fe-NTA toxicity is caused by lipid peroxidation. Al-NTA can be used as an animal model of renal osteodystrophy. Osteodystrophy by Al in chronic renal failure may be mediated by the intrinsic chelator or chelating substance(s) retained in the body fluid due to renal insufficiency.

Aluminum↗
PubMed1991

Distribution and immunochemical specificities of fimbriae of Porphyromonas gingivalis and related bacterial species.

Rabbit polyclonal antibody (Poly-1) and mouse monoclonal antibodies (mAbs) TO-11, TO-14 and TO-M1 specific for Porphyromonas gingivalis 381 fimbriae were prepared. Poly-1 and the 3 mAbs were screened for their reactivity with whole cells oral and nonoral black-pigmented bacterial species by enzyme-linked immunosorbent assay (ELISA) and the binding experiment using [125I]Poly-1 and [125I]mAbs. ELISA revealed that Poly-1 definitely reacted with whole cells of all the 11 strains of P. gingivalis tested. However, 8 of 11 P. gingivalis strains reacted with mAbs TO-11, TO-14 and TO-M1. These results were confirmed by the specific binding of radiolabelled Poly-1 and mAb TO-11 to the 8 strains. The M(r) of the fimbrial subunit protein (fimbrilin) isolated and purified from P. gingivalis strains 381, BH18/10, HW24D-1, 6/26 and OMZ 314 was 41 kDa by sodium dodecylsulfate-polyacrylamide gel electrophoresis. It was found by immunoblotting that mAbs TO-11 and TO-14/TO-M1 recognized different epitopes of fimbrial protein from P. gingivalis strains. Immunoelectron micrographs of whole cells and the purified fimbriae of P. gingivalis strains visualized similar serotype-specific antibody bindings to the fimbriae. These results indicate that 11 strains of P. gingivalis could be divided into at least 2 separate groups based on the immunochemical specificities of the fimbriae.

Animals↗
PubMed1991

Effects of color CRT display on pupil size in color-blind subjects.

The effects of color cathode ray tube (CRT) display on the pupil size in color-blind subjects were studied experimentally. Red, magenta, green, cyan, yellow, and white were presented on the CRT. Five protan subjects, five deutans, and five normal subjects were tested using infrared pupillography. In the protan group, the pupils were significantly less sensitive to red (wavelength: 600 nm) targets compared to the other colors. In the deutans and the control group, there were non-significant changes in pupil size in response to the colors. Dominant wavelengths above 600 nm in color CRTs should be avoided in routine work presentation because of less sensitivity in protanopias.

Adult↗
PubMed1991

[Study of prognostic factors of survival in patients with unresectable non-small cell lung cancer].

We studied prognostic factors of survival in 121 patients unresectable non-small cell lung cancer treated between March 1983 and November 1988 at forth department of internal medicine, Kinki university school of medicine, about histology, clinical stage, age, sex, performance status, Brinkman Index, hemoglobin, serum TP, serum Alb, serum LDH, pulmonary function and chemotherapy. The prognostic factors were studied using survival rate by Kaplan-Meier method, univariate analysis by Log-rank test and generalized Wilcoxon test and multivariate analysis by proportional hazard model of Cox. The prognostic factors of pretreatment were age, serum Alb, serum LDH, pulmonary dysfunction of mixed type and performance status. In the classified study according to histology, age and pulmonary dysfunction of mixed type were prognostic importance in patients with squamous cell lung cancer. Hemoglobin in patients with squamous cell lung cancer was important, too. The chemotherapy given good response improved patient's prognosis.

Adenocarcinoma↗
PubMed1990

Ultrastructural and cytochemical study of elastic fibers in the ventral aorta of a teleost, Anguilla japonica.

Previous studies have revealed that amorphous elastin and microfibrils are structural entities of mammalian elastic fibers. Elastin shows a wide phylogenetic distribution, but the presence of elastin-associated microfibrils has not been demonstrated in teleost aorta. Thus, we have ultrastructurally and cytochemically examined elastic fibers in the ventral aorta of eel, a teleost, by utilizing routine uranyl acetate and lead double staining, the tannic acid (pH 7.0)-uranyl acetate (TA-UA) method, elastase en bloc digestion, Thiéry's periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method, and the horseradish-peroxidase-labeled concanavalin A (Con A) method. In the ventral aorta of eel, a little ultrastructural difference between elastic fibers in the intima and media and those in the adventitia was noticed, but in either tunic each elastic fiber was basically composed of a "fibrillar core" and surrounding microfibrils. The fibrillar core was a collection of fibrils which showed a tendency to coalesce with each other, and these constituent fibrils were TA-UA positive and elastase-sensitive, representing their nature of elastin. By contrast, microfibrils associated with the fibrillar core were TA-UA negative and elastase-resistant, and their glycoproteinaceous nature was demonstrated by PA-TCH-SP and Con A methods. Thus, this study provides evidence for the presence of elastin-associated microfibrils in teleost aorta. These results are discussed in relation to the topographical difference of elastic fibers in eel aortic wall.

Anguilla↗
PubMed1990

A new depsipeptide antibiotic, citropeptin.

An actinomycete identified as Streptomyces flavidovirens was found to produce a new cyclic hexadepsipeptide antibiotic, designated citropeptin. Citropeptin showed antitumor activity against P388 murine leukemia.

Animals↗
PubMed1989

Ultrastructural cytochemistry of aortic microfibrils in the Arctic lamprey, Lampetra japonica.

In the ventral aorta of lamprey, microfibrils are major components of the extracellular matrix. With special reference to these microfibrils, we have cytochemically examined the lamprey ventral aorta, utilizing the tannic acid (pH 7.0)-uranyl acetate (TA-UA) method, elastase en bloc digestion, Thiéry's periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method, and ferritin- or horseradish peroxidase-labeled concanavalin A (Con A) methods. The lamprey microfibrils were strongly stained with PA-TCH-SP and both Con A methods, but did not show TA-UA staining nor elastase sensitivity. These cytochemical properties of lamprey microfibrils are identical with those of mammalian elastin-associated microfibrils. On the other hand, in spite of extensive examination, TA-UA positive and elastase-sensitive extracellular components were not found, so that lamprey ventral aorta does not appear to contain elastin. These results indicate that lamprey aortic connective tissue contains microfibrils as elastic components, but deposition of amorphous elastin does not occur.

Actin Cytoskeleton↗
PubMed1989

Immunocytochemical demonstration of amelogenins and enamelins secreted by ameloblasts during the secretory and maturation stages.

Rabbit polyclonal antibodies against bovine amelogenins and enamelins which did not show any cross-reaction were raised, and ultrathin sections of rat incisors were examined by the protein A-gold and ABC methods. The immunoreactivity of amelogenins was found in dense granules in the intercellular spaces between preameloblasts, and later over the fine- and coarse-textured material. The immunoreactivity was present over the cell organelles associated with the secretory pathway, as well as pale and dark lysosomes of the presecretory and secretory ameloblasts. Here the enamel was immunolabeled in the intercrystal spaces. The immunoreactivity in multivesicular bodies was stronger in preameloblasts than in secretory ameloblasts. In the region of second ruffle-ended ameloblasts at the maturation stage, the immunolabeling was intense in the ruffled-border, but in the rough endoplasmic reticulum and Golgi apparatus, the immunolabeling was much weaker than at the secretory stage. The immunolabeling for enamelins showed essentially the same intracellular topographical pattern as that for amelogenins by the secretory stage, but was weaker. The immunoreactivity was found mainly attached to the enamel crystals. Double immunostaining of amelogenins and enamelins revealed that both immunoreactivities were present over the same cell organelles associated with secretion and lysosomal systems. It is suggested that the presecretory and secretory ameloblasts are actively involved in the secretion, degradation and resorption of enamel proteins, and that multivesicular bodies and lysosomes in the cells take part in these processes. Ameloblasts are considered to be related to the synthesis of enamelins.

Ameloblasts↗
PubMed1988

Phosphoprotein synthesis and secretion by odontoblasts in rat incisors as revealed by electron microscopic radioautography.

The secretory pathway of dentin phosphoproteins in rat incisors was studied by electron microscopic radioautography after the injection of 3H-serine, and the results were compared with those using 3H-proline as a tracer. Five min after injection of 3H-serine, radioactivity was found in the rough endoplasmic reticulum. At 10 min, silver grains were observed over the spherical portions of the cisface of the Golgi apparatus. At 20 min after injection, silver grains were seen over the cylindrical portions of the transface of the Golgi apparatus. The secretory granules showed the strongest reaction from 20 min to 1 hr. At 45 min, a significant labeled band appeared at the mineralization front. At 1 hr, the labeling at the mineralization front began to appear in the mineralized dentin, and after 12 hr this labeled band was located within the mineralized dentin. The pathway of 3H-proline was essentially the same as that of 3H-serine, but 3H-proline moved more slowly than 3H-serine, especially in transit from the rough endoplasmic reticulum to the Golgi apparatus. Secretory granules were heavily labeled from 30 min to 1 hr after injection of 3H-proline; no labeling was found at the mineralization front at 45 min. The labeling seen initially over the predentin was over the mineralized dentin no earlier than 6 hr after injection. The labeling pattern with 3H-serine is closely related to the localization of phosphoproteins, whereas the pattern with 3H-proline reflects the production of collagen rather than of phosphoproteins. The present radioautographic results indicate that dentin phosphoproteins are related to secretory granules and are secreted by odontoblasts at the mineralization front and also that phosphoproteins are involved in the process of mineralization of the circumpulpal dentin.

Animals↗