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Biomedical subjects

M Kamiya

Publications and source records attributed to M Kamiya.

At least 73 records · Page 4Linked to original sources
PubMed1997

Role of host immune response in the occurrence of gastropathy in rats infected with larval Taenia taeniaeformis.

Decrease of spleen weight from peak to control levels together with a corresponding decline of serum IgG level at the onset of gastric hyperplasia in Taenia taeniaeformis-infected euthymic rats, may indicate that a form of down regulation of host immune response during the course of larval T. taeniaeformis infection could facilitate the occurrence of gastropathy in rats. Gastric hyperplasia developed in T. taeniaeformis-infected athymic nude rats, indicating that occurrence of gastropathy associated with larval T. taeniaeformis infection in the rat is T cell independent. Apparently, gastric hyperplasia appeared early in nude rats which suggests that absence of T cell-mediated response could have facilitated its early occurrence.

Animals↗
PubMed1997

Metazoan parasites of sika deer from east Hokkaido, Japan and ecological analyses of their abomasal nematodes.

Metazoan parasites of 50 sika deer (Cervus nippon yezoensis) collected in March 1991 in the Ashoro District in east Hokkaido, Japan, were evaluated. Ten species of helminths and three species of ectoparasites were obtained. Estimated abundance of males of two species of abomasal nematodes, Spiculopteragia houdemeri and Rinadia andreevae, were positively correlated with each other, and were overdispersed; S. houdemeri followed Poisson's and R. andreevae followed a negative binomial distribution. No significant relationship was detected between the estimated abundance of males of these two nematode species and nutritional condition of the hosts. Using a general linear model, the fourth-root transformed estimated abundance of male S. houndemeri was influenced by the main effects of host sex and age. This phenomenon was attributable to the ecological and behavioral features of the deer. The low diversity of the abomasal nematode community was regarded as the result of the extinction of some species of nematodes on Hokkaido Island.

Abomasum↗
PubMed1997

Effect of ultraviolet radiation on the infectivity of Taenia taeniaeformis eggs.

The effect of ultraviolet (UV) radiation on the infectivity of Taenia taeniaeformis eggs was observed. The eggs were exposed to various UV doses and orally inoculated to rats. The number of cysts and lesions decreased dose-dependently, and neither cyst nor lesion was observed from rats infected with eggs exposed to a total dose of 2,880 mJ/cm2 or more. For evaluation of protective role of embryophore against UV radiation, the onchospheres with/without embryophore were exposed to UV radiation. Remarkably lower numbers of cyst and lesions were observed in rats inoculated with eggs which were exposed to a total dose of 30 mJ/cm2 or more after removal of embryophore. These results suggested an importance of the protective function of the embryophore in the protection against UV radiation.

Animals↗
PubMed1997

Metacercariae in fishes of Sun Moon lake which is an endemic area for Clonorchis sinensis in Taiwan.

The Sun Moon lake in Central Taiwan is a known endemic area for clonorchiasis. Of the 45 fresh water fish, Hemiculter leucisculus, from the lake that were examined by artificial gastric juice digestion in October 1995, all were found to harbor metacercariae in their muscle. The number of metacercariae isolated from each fish ranged from 2 to 2,185, with an average of 254. A total of 11,443 metacercariae was collected from the 45 fish. Of the 4,223 metacercaria that were examined under light microscope, 4,064 (96.23%) were found to belong to Haplorchis taichui, 90(2.13%) to H. pumilio, 2(0.05%) to C. sinensis and 67 (1.59%) to unknown species due to the metacercariae being not yet developed or immature. The 2 C. sinensis metacercariae were obtained from 2 out of 45 fish examined. Our results contrast with reports of a decade ago which stated that all the fish of the Sun Moon lake examined were positive for C. sinensis. Possible reasons for the decrease of C. sinensis metacercariae are the disappearance of pig farms around the lake, increased awareness of the trematode by the lakeside inhabitants and probably the exclusive use of mammals as its definitive host by C. sinensis. In contrast, besides mammals, Haplorchis spp also use birds as their definitive hosts.

Animals↗
PubMed1996

Stereoselective action of (R*,R*)-(+/-)-methyl-4-[2-[2-hydroxy-2-(3-chlorophenyl)ethylamino] propyl]-phenoxyacetic acid (BRL37344) on beta-adrenoceptors and metabolic chiral inversion.

Stereoisomers of BRL37344 ((R*,R*)-(+/-)-methyl-4-[2-[2-hydroxy-2 -(3-chlorophenyl)ethylamino]propyl]-phenoxyacetic acid), a beta 3-adrenoceptor agonist, were synthesized and separated with good resolution by derivatization with 1-anthroyl cyanide prior to chiral HPLC. Agonist effects on rat right atria, guinea pig trachea, and rat brown adipocytes were due principally to the (RR) isomer, while other isomers (SS, RS, and SR) were much less potent or inactive. Since the racemate (RR +/- SS) was half as potent as the (RR) isomer in all specimens tested, the (SS) isomer does not appear to have antagonistic effects. When [14C](RR)BRL35135A ((R*,R*)-(+/-)-methyl-4-[2-[2-hydroxy-2-(3-chlorophenyl)ethylamino]propy l] -phenoxyacetate hydrobromide), the HBr salt of the methyl ester of BRL37344, was administered orally to male Wistar rats, both the (RR) and (SR) isomers of [14C]BRL37344 were detected in plasma, while only the (SS) isomer of [14C]BRL37344 was detected after [14C](SS)BRL35135A administration. These findings indicate that there is clear stereoselectivity in the effects of BRL37344 on beta-adrenoceptors, and that stereoselective chiral inversion from the RR isomer to the SR isomer occurs in rats.

Adipose Tissue, Brown↗
PubMed1996

High-efficiency full-length cDNA cloning by biotinylated CAP trapper.

We have devised a method for efficiently constructing high-content full-length cDNA libraries based on chemical introduction of a biotin group into the diol residue of the cap structure of eukaryotic mRNA, followed by RNase I treatment to select full-length cDNA. The selection occurs by trapping the biotin residue at the cap sites using streptavidin-coated magnetic beads, thus eliminating incompletely synthesized cDNAs. When this method was used to construct a mouse brain full-length cDNA library, our evaluation showed that more than 95% of the total clones were of full length, and recombinant clones could be produced with high efficiency (1.2 x 10(7)/10 micrograms starting mRNA). The analysis of 120 randomly picked clones indicates an unbiased representation of the starting mRNA population.

Animals↗
PubMed1996

Five candidate genes for hamster cardiomyopathy did not map to the cardiomyopathy locus by FISH analysis.

The Syrian cardiomyopathic hamster (BIO14.6), that develops both muscular dystrophy and progressive cardiomyopathy, is widely used as an animal model of autosomal recessive cardiomyopathy mimicking human hypertrophic cardiomyopathy, and five genes have been proposed as strong candidates for the cause of cardiomyopathy. We recently mapped the cardiomyopathy locus of the hamster to the centromeric region of chromosome 9qa2.1-b1 by construction of a genetic linkage map of the Syrian hamster. Thus, we analyzed the loci of the five candidate genes, alpha tropomyosin, cardiac troponin T, adhalin, calpain 3 and cardiac myosin binding protein-C, by the FISH method, and found that these genes were mapped on the distal portion of chromosome 12qa5 and 4pa2 and the proximal portion of chromosomes 9qb7, 1qc1.1 and 1qb3, respectively. These results provide strong evidence that the five candidate genes previously proposed are not related to the hamster cardiomyopathy.

Animals↗
PubMed1996

Inactive allele-specific methylation and chromatin structure of the imprinted gene U2af1-rs1 on mouse chromosome 11.

The imprinted U2af1-rs1 gene that maps to mouse chromosome 11 is predominately expressed from the paternal allele. We examined the methylation of genomic sequences in and around the U2af1-rs1 locus to establish the extent of sequence modifications that accompanied the silencing of the maternal allele. The analysis of HapII or HhaI sites showed that the silent maternal allele was hypermethylated in a block of CpG sequences that covered more than 10 kb. By comparison, the expressed paternal allele was unmethylated from a CpG island upstream of the transcribed region through 2 kb. An analysis of DNaseI hypersensitivity of a putative promoter of U2af1-rs1 showed an open chromatin conformation only on the unmethylated, expressed paternal allele. These results suggest that allele-specific hypermethylation covering the gene and its upstream CpG island plays a role in maternal allele repression of U2af1-rs1, which is reflected in altered chromatin conformation of DNaseI hypersensitive sites.

Alleles↗
PubMed1996

Time course of coproantigen excretion in Echinococcus multilocularis infections in foxes and an alternative definitive host, golden hamsters.

Coproantigen excretion during experimental infections of Echinococcus multilocularis in foxes and an alternative definitive host, golden hamsters, was evaluated by a sandwich ELISA using a monoclonal antibody. A sigmoidal increase of antigen excretion from the developing parasites was observed in in vitro incubation of the parasites collected on different days during the first 21 days post-infection (DPI). In hamsters, the ELISA O.D. value of faeces became positive at 4 DPI. Thereafter, the O.D. value increased in semi-sigmoidal fashion in the first 42 DPI, probably reflecting the development of the parasites. In foxes, the O.D. value became positive at 6 DPI. However, contrary to that in hamsters, after the initial steep rise, the O.D. value suddenly decreased to 1/2 the level during 15-17 DPI, indicating that a large number of worms might have been expelled. The parasite eggs were detected by the sugar centrifugal-flotation technique (Ito, Yagi & Ishige, 1989) from 29 to 84 DPI but not thereafter to 125 DPI, although mature parasites were detected at 125 DPI. In contrast, positive O.D. values were obtained almost constantly until 125 DPI, indicating that the coproantigen detection assay was more sensitive than the egg detection assay. The detection limit of the coproantigen assay was roughly estimated to be around 100 worms. These observations, along with the fact that the assay was designed to detect a heat-resistant coproantigen in heat-sterilized fecal samples, indicate that the coproantigen detection assay is a safe and useful method, not only for diagnosis in the definitive host of E. multilocularis, but also for monitoring parasite development and change in parasite burden during an experimental infection.

Animals↗
PubMed1996

A genetic linkage map of the Syrian hamster and localization of cardiomyopathy locus on chromosome 9qa2.1-b1 using RLGS spot-mapping.

The Syrian cardiomyopathic hamster (BIO14.6) has an inherited form of progressive myocardial necrosis and congestive heart failure. Although widely studied as an animal model for human hypertrophic cardiomyopathy, further genetic analysis has been limited by a scarcity of DNA markers. Until now, only six autosomal linkage groups have been described and the number of polymorphic loci was extremely limited. In this study, we applied the restriction landmark genome scanning (RLGS) spot-mapping method to construct a genetic map of the Syrian hamster (Mesocricetus auratus) using 72 back-cross progeny. Although the polymorphic rate is very low (3-7%) between the strains, 531 polymorphic spots/loci were mapped, showing the power of this approach and reasonable applicability to other organisms lacking a well-defined genetic map. Further, the spot markers which flank the cardiomyopathy (cm) locus were cloned to determine the chromosomal location of cm by fluorescent in situ hybridization (FISH) analysis, resulting in the assignment of the locus to the centromeric region of hamster chromosome 9qa2.1-b1. Several candidate genes responsible for hypertrophic cardiomyopathy in humans have been excluded.

Animals↗
PubMed1996

Enzymatic synthesis of two isoxazolylalanine isomers by cysteine synthases in Lathyrus species.

Two isoxazolylalanine isomers, beta-(isoxazolin-5-on-2-yl)-L-alanine (BIA, 1) and beta-(isoxazolin-5-on-4-yl)-L- alanine (TAN-950A, 2) were confirmed to be derived from O-acetyl-L-serine (OAS) and isoxazolin-5-one by cysteine synthases (CSases) with a different ratio in different plant parts. Some properties of this enzyme in the biosynthesis of both isomers are described.

Alanine↗
PubMed1996

Echinococcus multilocularis coproantigen detection in golden hamster, an alternative definitive host.

Golden hamsters as alternative definitive hosts of Echinococcus multilocularis were used for coproantigen detection by means of sandwich ELISA. The test was performed in hamsters infected with approximately 20,000, 4,000, 500, 0 (control) and 100,000 (i.e., group I, II, III, IV and V respectively) protoscoleces. Comparison of mean OD values of each group showed significant differences depending on the number of protoscoleces administered and days postinfection. There was also a relatively high statistical correlation between the number of recovered worms and ELISA OD values (correlation coefficient = 0.699, P < 0.05), although accurate comparison of worm burdens among individual animals was difficult when numbers of infecting worms fell within the same range.

Animals↗
PubMed1996

Parenteral strobilar development of Echinococcus multilocularis in scid mice.

Parenteral strobilation of Echinococcus multilocularis was observed in acid (severe combined immuno-deficient) mice after intracerebral, subcutaneous and intraperitoneal inoculation with protoscoleces. Evaginated protoscoleces and segmented worms were obtained at the inoculated sites. Most worms recovered from peritoneal cavity of scid mice were encapsulated by connective tissue and granulocytes but showed a maximum of 3 proglottids, elongation of genital primordia and vesiculation. Viability of worms recovered from the subcutaneous tissue and peritoneal cavity of scid mice were higher (69.1-91.4%) than those from the immunologically normal C.B-17 (4.0-48.0%) control mice. However, viabilities of worms from the cerebrum of both scid and C.B-17 were almost the same (87.7-94.4%). Worms recovered from scid mice showed further development of reproductive organs when transplanted into the small intestine of prednisolone treated golden hamster. These findings suggest that the parenteral milieu of scid mice allows adult development of E. multilocularis protoscoleces.

Animals↗
PubMed1996

Developmental study of Taenia mustelae in the intermediate and definitive hosts, with a note on the life cycle of T. mustelae in Hokkaido, Japan.

The gray red-backed vole Clethrionomys rufocanus bedfordiae and laboratory mice were fed eggs of Taenia mustelae via a stomach tube. Fully developed metacestodes were recovered from the voles fed the eggs at 25 days postinfection; voles were considered to be more suitable intermediate hosts for T. mustelae than laboratory mice. The prepatent period for the metacestodes from voles was shorter (16 days) in the mink than previously reported. A field survey was performed on hepatic cestodes of small mammals in Hokkaido, Japan in August 1993. We found T. mustelae metacestodes from C. rufocanus bedfordiae, representing a new host record.

Animals↗
PubMed1996

Comparison of serodiagnostic tests and ultrasonography for cystic hydatidosis in an epidemiological study of rural Uruguay.

Cystic hydatidosis (CH) caused by Echinococcus granulosus is an important zoonosis worldwide. Several serodiagnostic and ultrasound tests are currently used for screening asymptomatic CH. The sensitivity of the serodiagnostic tests has been demonstrated by several groups to be lower than ultrasonography (US). To explain the mechanism of the difference in sensitivity, a large-scale US survey combined with an IgG4-enzyme-linked immunosorbent assay test was conducted in Uruguay. Our results suggest that certain cyst images, e.g., multivesicular cysts, may be closely associated with a high antibody response regardless of the cyst size, whereas other hydatid lesions, e.g., solid images with/without rolled parasite membranes, have lower antibody responses with a close relationship to cyst size. Seropositivity of subjects who had been treated surgically for removal of hydatid cysts in the last 5 yr was closest to that of actual CH patients, albeit free from CH by US. These findings are important for the proper use of serodiagnostic tests and US for community-based epidemiological studies.

Animals↗
PubMed1995

Changes in subcellular and zonal distribution of glucokinase in rat liver during postnatal development.

Subcellular and zonal distribution of glucokinase in rat liver during postnatal development was examined immunohistochemically. Before day 11 after birth, only some hepatocytes were immunostained, and a positive immunostaining was found in the cytoplasm but not in the nucleus. No zonal distribution of glucokinase was observed in livers of such pups. From day 15, at which time a dietary change from milk to laboratory chow begins to take place, glucokinase immunoreactivity increased; this increase was associated with increases in glucokinase activity and in glucokinase protein, and also the immunostaining was observed mainly in the nuclei. At day 21, the glucokinase immunoreactivity was found almost exclusively in the perivenous zone. At day 30, an intense immunostaining was seen both in the perivenous zone and in the periportal zone, being slightly predominant in the former. The present results indicate that dramatic changes in the distribution of glucokinase in developing rat liver may be related to dietary change.

Aging↗