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Biomedical subjects

H Kito

Publications and source records attributed to H Kito.

85 records · Page 5Linked to original sources
PubMed1982

Formation and possible role of bis(methylmercuric) selenide in rats treated with methylmercury and selenite.

The metabolic fate of methylmercury after administration of [203Hg]-methylmercuric chloride in combination with sodium selenite was investigated in rats. Whole body autoradiography and radioassay showed that administration of selenite decreased the mercury concentration in the liver and kidney, and increased that in the brain. The rapid changes of methylmercury concentration in the tissues after selenite injection were accompanied by increase in mercury extractable with benzene at neutral pH. The maximum levels of benzene-extractable mercury in the blood, kidney and liver were attained 30 min after selenite injection and were 30, 23 and 8 percent, respectively, of the total mercury. Thin-layer chromatography showed that the benzene-extractable mercury was a complex of methylmercury with selenium, bis(methylmercuric) selenide. These findings indicate that selenite alters the distribution of methylmercury in the tissues by formation of a diffusible complex with methylmercury, bis(methylmercuric) selenide.

Animals↗
PubMed1982

Separation and purification of (Cd, Cu, Zn)-metallothionein in carp hepato-pancreas.

1. Cd-binding protein was isolated from the hepato-pancreas of carp administered CdCl2 (2 mg/kg). 2. This protein had a high absorption at 254 nm derived from Cd-mercaptide binding, and a low absorption at 280 nm derived from the absence of aromatic amino acids; the authors recognized the presence of two types. 3. The amino acid composition of the proteins was determined. The contents of cysteine residues were 34.24% and 31.90% in MT-I and -II respectively. Tyrosine, phenylalanine, tryptophan, histidine, leucine and arginine residues were absent in both types.

Amino Acids↗
PubMed1982

Formation of metallothionein in fish.

1. Carp were bred in Cd solution, and each organ was homogenized and centrifuged at 105,000 g. The Cd content of the supernatant was much more than that of the precipitate. 2. In examining the metal form in the supernatant, the induction of metallothionein (MT) was found in carp exposed to Cd and Zn solutions and the presence of metallothionein was found in fish captured in Nagara river and breeding ponds. 3. Cd content in the metallothionein fraction of hepato-pancreas increased at the early stages of exposure, but Cd in the metallothionein fraction of the other organs increased as time proceeded. 4. In the tap water group, metallothionein in hepato-pancreas and kidney contained Cu, and increased with the induction of metallothionein in hepato-pancreas due to Zn-exposure.

Animals↗
PubMed1982

Protection by metallothionein against cadmium toxicity.

1. The protective effect against Cd toxicity of prior exposure to Cd or Zn solutions at low concentration was studied. 2. Carp were bred in tap water (A), 1 ppm Cd solution (B) and 5 ppm Zn solution (C) for 14 days and then transferred into 15 ppm Cd solution. The survival ratio of carp decreased in the order: (C):(B):(A). 3. Binding capacity of Cd to high molecular and metallothionein fractions in the cytoplasmic solutions of the hepato-pancreas was studied and the binding capacity to the metallothionein fraction was stronger than that to the high molecular fraction. The authors recognized that Zn in the metallothionein fraction is substituted by Cd.

Animals↗
PubMed1980

The age distribution of neutralizing antibodies against varicella-zoster virus in healthy individuals.

A seroepidemiological survey of varicella was made in the Nagoya area by the neutralization (NT) test. Of 1,473 recorded cases of varicella, 81.4% were under 6 years old and 9.6% were under one year old; of the 168 recorded cases under one year old, about 30% were under 5 months old. Examination of 11 pairs of mother and cord sera and 13 pairs of mother and infant sera showed that transfer of NT antibody was in general good, even in babies that were small for their age or smnall at birth after 28 weeks gestation. The transferred maternal antibody decreased rapidly, becoming undetectable in babies of 4 months old. Then with increase in age the percentgage of seropositive children gradually increased, being 53.3% at 4 to 5 years old, and 100% in those of over 9 years old, with a temporary decrease in young adults in their twenties.

Adolescent↗
PubMed1975

Tumor of glomus jugulare report of a case.

A typical case of glomus jugulare tumor was presented. This 42-year-old man suffering from a left-sided impaired hearing progressive over a five year period was found to have a small hemorrhagic polypoid tumor in the left external auditory canal. After repeated surgical treatments the tumor removed was light and electron microscopically diagnosed as glomus jugulare tumor which corresponded to the 13th case in this country. The implication that this tumor may constitute a distinctive group of tumor among the neuroendocrine tumors from other sites was discussed from the facts of the presence of a large number of rather small argyrophilic granules of secretory type in the cytoplasm of tumor cells including the present case and of the appearance of increasing cases with functioning glomus jugulare tumor secreting catecholamine in the recent medical literature.

Adult↗
PubMedDate not supplied

Dose-response relationship between total cadmium intake and prevalence of renal dysfunction using general linear models.

To determine the maximum allowable intake limits for chronic dietary exposure to cadmium (Cd), the dose-response relationship between total Cd intake and prevalence of renal dysfunction was examined using general linear models considering the effect of age as a confounder. The target population comprised 1850 Cd-exposed and 294 non-exposed inhabitants of Ishikawa, Japan. They were divided into 96 subgroups by sex, age (four categories) cadmium concentrations in rice (three categories) and length of residence (four categories). As indicators of the cadmium-induced renal dysfunction, glucose, total protein, amino nitrogen, beta 2-microglobulin and metallothionein in urine were employed. General linear models were fitted statistically to the relationship among prevalence of renal dysfunction, sex, age and total Cd intake. Prevalence of abnormal urinary findings other than glucosuria had significant associations with total Cd intake. When total Cd intake corresponding to the mean prevalence of each abnormal urinary finding in the non-exposed subjects was calculated using general linear models, total Cd intakes corresponding to glucosuria, proteinuria, aminoaciduria (men only) and proteinuria with glucosuria were determined to be ca. 2.2-3.8 g and those corresponding to prevalence of metallothioneinuria were calculated as ca. 1.5-2.6 g. The low-molecular-weight protein in urine was confirmed to be a more sensitive indicator of renal dysfunction, and these total Cd intake values were close to those calculated previously by simple regression analysis, suggesting them to be reasonable values as the maximum allowable intake of Cd.

Age Distribution↗
PubMedDate not supplied

Is rectal carcinoid argyrophilic? Application of Grimelius' silver nitrate stain in four cases.

In four cases, small rectal carcinoids from patients who did not have accompanying significant clinical signs or metabolic disturbances were found to give a definite argyrophil reaction by double or triple impregnation of Grimelius' silver nitrate stain, but not by other silver methods for argyrophil or argentaffin granules, regardless of variations of cellular arrangement in ribbon-like, solid, and sclerosing patterns. The implication that the carcinoid tumor occurring in the rectum may constitute a group distinct from carcinoids arising from other sites is discussed.

Adult↗
PubMedDate not supplied

A total delivery system of genetically engineered drugs or cells for diseased vessels. Concept, materials, and fabricated prototype device.

The development of a percutaneous procedure using a catheterized system for diseased vessels has been increasingly in demand in conjunction with gene therapy using genetically engineered drugs (antisense) and cells. The authors' strategic concept realizes revascularization at narrowed, diseased sites and delivery of drugs or cells into the diseased tissues or targeted cells. An inflatable, drug-releasing double balloon is installed at the tip of a catheter. The outer balloon, fabricated with micropores (diameters of 20 and 30 mm) by an excimer laser ablation technique, releases a viscous solution containing a photoreactive polymer and drug or cells on inflation of the inner balloon. A photoresponsive water-soluble polymer, molecularly designed for its ability to achieve prolonged local residency of antisense DNA at the tissue level and enhanced transmembrane transport at the cellular level, is premixed with antisense oligonucleotide drug. On light irradiation, the nonionic polymer is reversibly converted to a positively charged polymer that can be complexed with highly negatively charged antisense DNA (c-myb), which may enhance the transmembrane delivery of antisense. On cessation of irradiation, the complex slowly dissociates to function intracellularly as an antisense drug, resulting in inhibition of cell proliferation. Thus, our integrated, dual-function balloon system may contribute to mechanical dilatation gene therapies at diseased vessels.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Effect of sealant viscosity on the penetration of resin into etched human enamel.

This study was designed to investigate the relationship between the etched depth, penetration of sealants and marginal seal. Sixty unerupted lower first premolars extracted from patients for orthodontic reasons were thoroughly cleaned and stored in an antiseptic Ringer's solution at 4 degrees C. A "window" on the occlusal of 15 of the premolars, including both mesial and distal pits, was developed by painting nail varnish around the border of the occlusal surfaces. Etching was then done with 35% phosphoric acid for 60 seconds to all 60 premolars. Five of the "window" teeth were evaluated by microradiography to determine the etched depth of the superficial and subsurface enamel. Five were prepared for SEM analysis to observe the change of the superficial etched enamel surface. Another five "window" teeth were embedded in epoxy resin and sectioned parallel to the long axis of the tooth through the fissures in order to observe the subsurface depth of the etch by SEM analysis. The other 45 teeth were divided into three groups of 15 teeth each. Fissures of each group of teeth were sealed using Prisma-Shield (LD Caulk), Concise White Sealant (3M Dental Products) or Teethmate A (Kuraray) sealants and stored in water (37 degrees C) for 24 hours. They were then sectioned and demineralized before being examined by a scanning electron microscope. Photographs of secondary electron image (SEI) were done to gradate the resin-infiltrated enamel and resin tags for these sealants. After SEM observation, the 15 samples of each applied sealant were polished to a high gloss again and placed in a silver nitrate solution for 24 hours before being examined under the SEM equipped with a back-scatter electron detector. Data were then analyzed using the Welch and Student t-tests. Results showed that fissured enamel of unerupted human lower first premolars became porous after etching with 35% phosphoric acid. The low viscosity sealant Teethmate A (approximately 260 mPa.s), penetrated fully and formed a resin-infiltrated layer in enamel beyond the etched depth. However, the high viscosity sealants (Prisma-Shield and Concise White Sealant) did not penetrate enough to ensure that the acid-etched enamel was infiltrated sufficiently by the sealant to insure good marginal seals.

Acid Etching, Dental↗
PubMedDate not supplied

Differentiated biocompatible design of luminal and outer graft surfaces. Photocurable extracellular matrices, fabrication, and cellular response.

Differentiated biocompatible design of luminal and outer graft surfaces may lead to successful healing of vascular grafts. Non-cellular adhesion characteristics are required for a luminal surface, whereas enhanced cell adhesion and migration are desired for an outer surface. We molecularly designed photocurable extracellular matrices (ECMs). Photocurable chondroitin sulfate (CS) was prepared for the luminal surface and photocurable gelatin for the outer surface. Both were partially derivatized with photodimerizable groups such as cinnamate and coumarin. These ECMs were converted to produce water insoluble gels upon ultraviolet irradiation. In vitro study showed that platelet adhesion on the photogelled CS was significantly reduced, whereas endothelial cells adhered well to the photogelled gelatin. These materials were individually coated and photogelled onto respective surfaces of knitted Dacron grafts (internal diameter 5 mm, length 5 cm). The ECM coated grafts were implanted into the abdominal aortae of dogs. During acute phase implantation for up to 1 week, minimized cell adhesion was observed on the luminal surface where the photogelled CS had provided a uniform cover, and enhanced tissue ingrowth was noted at the outer surface. However, some thrombi were formed, probably because of incomplete coating of, or cracks in, the photogelled CS. Although the molecularly designed ECMs and their in vitro performance appeared to follow our concept, further improvements in coating technique and molecular design of ECMs are needed for better in vivo performance. This may result in enhanced tissue regeneration, as well as a high patency rate.

Animals↗