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.

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.

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.

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.

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.

Cytologic diagnosis of signet-ring cell carcinoma of the breast

OBJECTIVE

To examine the cytologic features of signet-ring cell carcinoma (SRCC), defined as carcinoma dominated by signet-ring cells, of the breast and to discuss problems that occur in cytodiagnosis.

STUDY DESIGN

Five cases of SRCC of the breast were examined cytopathologically. Signet-ring cells were subclassified into intracytoplasmic lumina (ICL) type and non-ICL type. ICL type had large ICL containing mucin. Non-ICL-type cells had wide, amorphous cytoplasm diffusely dispersed with mucin.

RESULTS

In cases 1 and 2, fine needle aspiration biopsy (FNAB) revealed many signet-ring cells (non-ICL type), suggesting SRCC. Histologic diagnoses were ductal SRCC containing many signet-ring cells (non-ICL type). In cases 3 and 4, signet-ring cells (ICL type) were found sporadically among carcinoma cells without signet-ring features. Signet-ring cells were not regarded as the major component of the cells; thus, the cytologic diagnoses were lobular carcinoma, not otherwise specified. Pathologic diagnoses were lobular SRCC. Signet-ring cells were mostly ICL type. In case 5, most carcinoma cells on the smears showed signet-ring features (non-ICL type), suggesting SRCC. The histologic diagnosis was lobular SRCC, and signet-ring cells were mostly non-ICL type.

CONCLUSION

Ductal SRCC yielded more cellular smears as compared with lobular SRCC; therefore, cytologic diagnosis was easier in the former.

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.

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.

[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.

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.

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%.

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.

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.

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.

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.

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.