Biomedical subjects

M Kamiya

Publications and source records attributed to M Kamiya.

At least 55 records · Page 3Linked to original sources

PubMed1999

Hyperplasia of gastric mucosa in donor rats orally infected with Taenia taeniaeformis eggs and in recipient rats surgically implanted with the larvae in the abdominal cavity.

Rats heavily infected with Taenia taeniaeformis larvae in the liver show a remarkable increase in their stomach weight, hyperplasia, and hypergastrinemia. However, it is unknown what causes these phenomena. Hence, as a preliminary study to investigate the importance of larval parasitism in the liver, two experiments were done. In the first experiment, 14 donor rats were orally inoculated with 3,000 T. taeniaeformis eggs. In the second experiment, 136-300 of the larvae obtained from the rats were surgically implanted into the abdominal cavity of 7 recipient rats. Gastrin levels and histopathological changes in the gastric mucosa were investigated. In all, 11 donor rats showed hypergastrinemia and hyperplasia, 5 recipient rats showed gastric mucosal hyperplasia accompanied by excessive mucous cell proliferation, and 2 recipient rats showed hypergastrinemia. These results suggest that parasitism of the liver by the larvae is not essential for the development of hyperplasia and that factors from the larvae might cause these phenomena.

Animals↗

PubMed1999

A new nematode, Ansiruptodera scapteromi sp.nov. (Nematoda: Aspidoderidae), recovered from the Argentinean water rat Scapteromys tumidis (Waterhouse, 1837) in Uruguay.

This report describes a new species of aspidoderid nematode, Ansiruptodera scapteromi sp. nov., the second species to be reported in the genus Ansiruptodera Skrjabin and Shikhobalova, 1947. The A. scapteromi sp. nov. is the first species of the genus to be recorded from a rodent host. The new species is clearly different from the only other species, A. ansiruipta (Proença, 1937) Skrjabin and Shikhobalova, 1947, in that it possesses short lateral alae that terminate before the midbody; a smaller cephalic extremity; a shorter esophagus, pharynx, tail, and tail appendage; a smaller sucker; and longer spicules. The two species also differ in the numbers and arrangements of caudal papillae. A. scapteromi appears to be a parasite of capture and the water rats seem to have been infected from Edentata in Uruguay.

Animals↗

PubMed1999

Cyclodextrin inclusion: catalytic effects on the degradation of organophosphorus pesticides in neutral aqueous solution.

alpha-, beta and gamma-Cyclodextrins were found to have promotive inclusion-catalytic effects on the degradation of organophosphorus pesticides solubilized in neutral aqueous media. Pesticide degradations were especially accelerated in such systems as alpha-cyclodextrin plus diazinon and beta-cyclodextrin plus chloropyrifos. The above findings are in contrast with the inhibitive catalytic effects of cyclodextrins on pesticide degradations in alkaline media. Cyclodextrin catalytic effects found here were considerably affected by differences in the substitutional and hetero-cyclic properties of the aromatic rings of pesticides and also by the sizes of cyclodextrin cavities.

Acetone↗

PubMed1999

Coproantigen survey for Echinococcus multilocularis prevalence of red foxes in Hokkaido, Japan.

An epidemiological survey was conducted on the seasonal variation of Echinococcus multilocularis prevalence in red foxes from 1997 to 1998, using a monoclonal antibody-based detection of the tapeworm coproantigen. Thirty-six breeding dens of reproductive fox families were identified in the endemic area of Koshimizu, eastern Hokkaido, Japan. Fecal samples from each site were examined by coproantigen detection assay and fecal egg examination. Whereas the prevalence of coproantigen positive feces showed no seasonal fluctuation (51.6-66.7%), variation was found in the prevalence of egg positive feces in which a higher prevalence was observed in the summer and winter (31.1 and 38.7%) than spring and autumn (13.3 and 13.5%). Significant differences were observed between juveniles and adult foxes in both examinations. Samples from juvenile foxes gave higher coproantigen positive results and taeniid egg intensity. Those results suggest more juveniles infected with the cestode than adults in the same period. The practical use of coproantigen assay as a survey tool and factors which affect the prevalence and host age-related difference are discussed.

Animals↗

PubMed1999

Pigmented squamous cell carcinoma with dendritic melanocyte colonization in the external auditory canal.

A case of pigmented squamous cell carcinoma (SCC) with dendritic melanocyte colonization in the external auditory canal is reported and the previous cases are reviewed. A 65-year-old Japanese female was referred with a 7-year history of otitis. The patient also had a darkly pigmented 9 x 8 mm nodule in the external auditory canal. Microscopically, the tumor was SCC, but in some areas melanin pigments were found in the cytoplasm of the tumor cells. The tumor was thus diagnosed as pigmented SCC. As well as the tumor cells, dendritic-shaped cells colonized the tumor parenchyma and were immunohistochemically defined as melanocytes. The authors believe this is the first case of pigmented SCC with dendritic melanocyte colonization in the external auditory canal.

Aged↗

PubMed1999

Histopathology and physiopathology of gastric mucous hyperplasia in rats heavily infected with Taenia taeniaeformis.

Rats heavily infected with larval Taenia taeniaeformis show hyperplasia of the gastric mucosa accompanied by mucous cell proliferation, increase in the level of intragastric pH and hypergastrinemia. Sixty one rats were divided into 2 groups designed as infected (36 rats) and control (25 rats) group. These rats were examined with time course of the infection histopathologically and physiopathologically, during 14-112 days postinfection (DPI). In the infected rats, gastric mucosal hyperplasia began to be observed at 56 DPI, and the structural disturbance of zymogenic units in the corpus and mucous units in the antrum had increased with time. However, the degree of these changes in the antrum was weaker than those in the corpus. Alcianblue and/or PAS-positive cells increased in their numbers with time, and 4 types of cells other than typical surface mucous cell and mucous neck cell were observed by electron-microscopy. However, zymogenic and parietal cells decreased in their number after 56 DPI. Further, the infected rats showed changes in the serum concentration of alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, glucose and total protein. Some similarities with Menetrier's disease were discussed.

Animals↗

PubMed1999

A second record of adult Ascarops strongylina (Rudolphi, 1819) (Nematoda: Spirocercidae) in a rodent host.

Mature adults of Ascarops strongylina (Nematoda: Spirocercidae) were collected from a Manchurian zokor, Myospalax psilurus (Rodentia: Cricetidae), in Mongolia. This is the second record of adult A. strongylina from wild rodents and the first for M. psilurus as a definitive host of this nematode. Remnants of ground crustaceans (Porcellio sp.) and a dung beetle (Onthophagus sp.) were also found in the stomach of the zokor.

Animals↗

PubMed1999

Evaluation of coproantigen diagnosis for natural Echinococcus multilocularis infection in red foxes.

The validity of a coproantigen ELISA for Echinococcus multilocularis was evaluated by comparison of three diagnostic methods; autopsy, egg examination and the ELISA. Of 71 foxes, 39 were found to be infected with the cestode at autopsy. The overall mean of worm burdens was 3,451, but the number varied (1-34,522). The ELISA could detect 94.9% (37/39) of the worm positives and there were no false-positives. Two false-negatives were infected with 1 and 4 cestodes, whereas 3 cases with similar worm burdens (2, 4 and 6 worms) were diagnosed as positives. This indicates the detection limit of the assay may be equivalent to less than 10 (in the worm burden). On the other hand, egg examination showed low sensitivity (43.6%, 17/39). These results suggest the ELISA has a potential to replace for the conventional methods.

Animals↗

PubMed1998

The human GNAS1 gene is imprinted and encodes distinct paternally and biallelically expressed G proteins.

The GNAS1 gene encodes the alpha subunit of the G protein Gs, which couples receptor binding by several hormones to activation of adenylate cyclase. Null mutations of GNAS1 cause pseudohypoparathyroidism (PHP) type Ia, in which hormone resistance occurs in association with a characteristic osteodystrophy. The observation that PHP Ia almost always is inherited maternally has led to the suggestion that GNAS1 may be an imprinted gene. Here, we show that, although Gsalpha expression (directed by the promoter upstream of exon 1) is biallelic, GNAS1 is indeed imprinted in a promoter-specific fashion. We used parthenogenetic lymphocyte DNA to screen by restriction landmark genomic scanning for loci showing differential methylation between paternal and maternal alleles. This screen identified a region that was found to be methylated exclusively on a maternal allele and was located approximately 35 kb upstream of GNAS1 exon 1. This region contains three novel exons that are spliced into alternative GNAS1 mRNA species, including one exon that encodes the human homologue of the large G protein XLalphas. Transcription of these novel mRNAs is exclusively from the paternal allele in all tissues examined. The differential imprinting of separate protein products of GNAS1 therefore may contribute to the anomalous inheritance of PHP Ia.

Alleles↗

PubMed1998

A methylation imprint mark in the mouse imprinted gene Grf1/Cdc25Mm locus shares a common feature with the U2afbp-rs gene: an association with a short tandem repeat and a hypermethylated region.

We identified a sperm-specific methylation imprint mark (Site II) associated with a short tandem repeat sequence and a site/region methylated in both gametes (Site I) in the Grf1 locus on mouse chromosome 9, which shared a common feature with the U2afbp-rs gene. Sites or regions of gamete-specific methylation in imprinted genes are strong candidates for carrying information regarding the parental origin of alleles. The gamete-specific methylation pattern of Sites I and II was conserved after fertilization, but attained the somatic cell pattern by the blastocyst stage. In primordial germ cells, Site I was methylated, but Site II was unmethylated in both male and female embryos, suggesting that the sperm-specific methylation imprint mark in Site II was established during spermatogenesis. These common features in methylation imprint regions may be a clue to identifying regions carrying primary information for the imprinting regulation.

Animals↗

PubMed1998

Time-course of antibody response in mice against oral infection with eggs of Echinococcus multilocularis.

The kinetics of serum antibody response against infection with Echinococcus multilocularis eggs was evaluated in AKR mice. The animals were infected by oral inoculation with 300 parasite eggs, and necropsied at 1, 2, 4, 6, 9, 12 and 16 weeks post-infection (p.i.), respectively. The parasite formed the laminated layer at 4 weeks p.i., the brood capsule with a massive proliferation of germinal cells at 9 weeks p.i. and protoscoleces at 16 weeks p.i. Serum antibody responses of the mice to antigen preparations from metacestodes of different stages and protoscoleces were evaluated by ELISA, immunoblotting and immunohistochemistry. In ELISA, the antibody responses began to increase at 4 weeks and became more apparent at 9 weeks p.i. and thereafter. Immunoblots using sera collected at 16 weeks p.i. showed some common bands among the 3 different antigen preparations. In addition to this, the germinal cells and brood capsules of mature metacestodes were stained strongly in an immunohistochemical study. From above, it is suggested that some antigen molecules are expressed in the parasite through these stages and stimulated host antibody responses.

Animals↗

PubMed1998

Monitoring of Echinococcus multilocularis infection in red foxes in Shiretoko, Japan, by coproantigen detection.

The study was conducted to evaluate a mAb-based coproantigen detection assay for monitoring fox prevalence of Echinococcus multilocularis infections in the Shiretoko National Park in Hokkaido, Japan. Eight fox families, each consisting of 2-4 adults and their pups, were selected because their territories have been determined. Faeces of each family (total n = 537) were collected monthly from April to October, 1994. Detection of coproantigen and taeniid eggs was recognized in 58 and 27 faeces, respectively, but mostly restricted in 1 family, in which coproantigen ELISA OD values had dual peaks, one in June and the other in October, whereas taeniid eggs were detected only from April to July. Fox pup faeces (n = 51) collected around the dens used by the positive family were all coproantigen and taeniid egg negative except for 1 faeces. These results suggest that the prevalence and infection pressure in the study area were low and the infected family terminated the infection in the summer and acquired a new one in the early autumn, 1994. This monitoring method for fox infection will be a practical management tool for E. multilocularis infection, especially at the tourist spots in Hokkaido where close contact of fox with humans is frequently observed.

Animals↗

PubMed1998

Coproantigen detection in a survey of Echinococcus multilocularis infection among red foxes, Vulpes vulpes schrencki, in Hokkaido, Japan.

Detection of Echinococcus coproantigen using sandwich enzyme-linked immunosorbent assay (sELISA) was performed on fecal samples of red foxes in Hokkaido, Japan. Fecal samples were collected around fox dens in 1990 and 1992. The antibodies used for sELISA recognize heat-resistant antigens, thus all fecal samples were heated to render it safe for handling before examination. Detection of taeniid egg in fox feces collected was considered as an indication of E. multilocularis infection. In fecal samples collected in 1990 and 1992, coproantigen positive results out of taeniid-egg positive cases were 38/40 (95.0%) and 95/97 (97.9%), respectively. In addition, coproantigen was detected regardless of fecal condition when collected from the field, suggesting that the antigens detected by this method are quite stable. These results suggest that detection of coproantigen is useful for field surveys of foxes naturally infected with E. multilocularis.

Animals↗

PubMed1998

[A case of cutaneous pseudallescheriosis resembling sporotrichosis].

An 83-year-old man with aplastic anemia and steroid induced diabetes mellitus developed multiple nodules with pus on the back of his right hand and forearm. He had been treated with a daily dose of 30mg prednisolone for 2 months. These lesions had appeared a month before his visit. The histopathological findings revealed dermal abscesses containing hyphal structures, lymphocytes, histiocytes and giant cells. Grocott-Methenamine stain demonstrated abundant fungal elements. In culture, colonies grow rapidly and produce a white, cottony mycelium which later becomes gray in color. Microscopically, ovoid and pyriform conidia are produced at the ends of long slender conidiophores. On PCA agar, synnemata with small conidal heads developed at 37 degrees C but cleistothecia did not appear. The patient did not respond to itraconazole therapy, however, with hyperthermic treatment, the eruptions gradually healed. Based on these findings, this fungal infection was diagnosed as pseudallescheriosis.

Aged↗

PubMed1998

Nitric oxide: a possible etiologic factor in spinal cord cavitation.

To determine whether nitric oxide (NO) is related to spinal cord cavitation, we treated mice that underwent spinal cord injury with NG-mono-methyl-L-arginine (N-MMA). Spinal cord specimens were subjected to glial fibrillary acidic protein (GFAP) immunostaining, which is selective for astrocytes. Spinal cord cavities and GFAP-positive glial cells appeared simultaneously at 3 days after spinal cord injury, and the cavities enlarged at 7 days. In mice receiving N-MMA, the cavities were significantly smaller than those in the mice that underwent spinal cord injury only. However, the numbers of GFAP-positive cells showed no difference between these two groups. These experimental findings suggest that cavitation of the spinal cord is caused mainly by NO released from activated glial cells.

Animals↗

PubMed1997

An oocyte-specific methylation imprint center in the mouse U2afbp-rs/U2af1-rs1 gene marks the establishment of allele-specific methylation during preimplantation development.

An oocyte-specific methylation imprint mark region, consisting of approximately 200 bp from the mouse imprinted gene U2afbp-rs, was identified within an area containing a CpG island and a short tandem repeat sequence. The oocyte-specific methylation was preserved in fertilized eggs and then expanded on the repressed maternal allele during preimplantation development until the adult methylation pattern was achieved by 12.5 days of embryonic development. These results indicate that the oocyte-specific imprinting mark region acts as a center in establishing the hypermethylated region on the repressed maternal allele. Furthermore, a region that is hypermethylated in both gametes was identified but its hypermethylation was conserved only on the maternal allele during preimplantation development, suggesting that some factor(s) inherited from oocytes may act to maintain hypermethylation on the maternal allele.

Alleles↗

PubMed1997

Linkage map of Syrian hamster with restriction landmark genomic scanning.

We have constructed the linkage map with precise genetic analysis of the Syrian hamster, Mesocricetus auratus, according to the restriction landmark genomic scanning (RLGS) spot mapping method. Although only 3.2-6.6% of the total RLGS spots between the two strains, ACN and BIO 14.6, showed genetic variance, 572 loci were found to be polymorphic. Out of 569 RLGS loci and 3 other loci, 531 were mapped with the backcross (ACN x BIO 14.6) F1 x BIO 14.6. The cumulative map was 1111.6 cM, indicating that the spots/loci are located throughout the genome at 1.94 cM intervals on average. Thus, RLGS provides us with a rapid tool to construct the genetic map of any species, even if it has less genetic variation.

Animals↗

PubMed1997

Coproantigen detection in dogs experimentally and naturally infected with Echinococcus granulosus by a monoclonal antibody-based enzyme-linked immunosorbent assay.

A sandwich ELISA for the detection of Echinococcus granulosus coproantigen in formalin and heat-treated faecal supernatants of dogs was developed. The assay used affinity-purified polyclonal antibodies obtained from rabbits hyperimmunised with E. granulosus excretory/secretory antigens and biotinylated monoclonal antibody EmA9 produced against adult E. multilocularis somatic extract. The test was sensitive to 7 ng and 2.3 ng of E. granulosus protein and carbohydrate/ml of faecal supernatant, respectively. Thirteen helminth-free dogs were infected with different amounts of E. granulosus protoscoleces and the presence of coproantigen was monitored during the prepatent period until day 35 post-infection, when they were necropsied. Faecal antigen levels started to rise above the normal range between days 10 and 20 post-infection, and typically peaked at the end of the experiment. All the dogs, bearing from 3 to 67,700 worms, showed positive values in the ELISA during the prepatent period. One dog experimentally infected with Taenia hydatigena metacestode and harbouring three worms, tested positive only after the prepatent period at day 52. The test was applied to 98 stray dogs. The ELISA detected all of four dogs naturally infected with E. granulosus, two dogs with patent infections of T. hydatigena and two dogs with no cestode infections, showing a sensitivity of 100% and a specificity of 96%.

Animals↗