Aberrant sparganosis in cat caused by Spirometra mansoni (Cestoda: Diphyllobothriidae): a case report

BACKGROUND

Sparganosis is a rare zoonotic disease caused by plerocercoid larvae of the genera Spirometra or Sparganum (Cestoda: Diphyllobothriidae). The larvae of Spirometra generally do not undergo asexual reproduction, whereas those of Sparganum can induce proliferative lesions in infected tissues. This paper presents an unusual case of proliferative sparganosis due to infection with Spirometra mansoni in a cat, normally considered a definitive host of the species.

CASE PRESENTATION

A 9-year-old male domestic cat was presented with a mass on the right side of the face that underwent progressive enlargement for 1 month. The morphological and histopathological examinations revealed multiple asexual proliferative cestode larvae in the lesions, suggestive of proliferative sparganosis. Next-generation sequencing analysis of formalin-fixed and paraffin-embedded specimens of surgically excised tissue indicated that the worm was Spirometra mansoni.

CONCLUSION

Although S. mansoni a common tapeworm species found in the small intestine of domestic cats and dogs in Japan, proliferative sparganosis is extremely rare. This is the first confirmed case of proliferative sparganosis due to infection with S. mansoni in cat.

A new species of Demodex (Acari: Demodecidae) from the skin of golden-handed tamarins, Saguinus midas (Primates: Cebidae)

Two captive-bred golden-handed tamarins, Saguinus midas L., 1758 (Primates: Cebidae), kept in households in Japan, presented with psoriasis-like plaques on their faces, along with scale, alopecia, and itching. Histopathological examination revealed numerous Demodex mites in the hair follicles, and the clinical symptoms in both cases improved after treatment with fluralaner. Based on the morphological and genetic characteristics of the mites collected from tamarins, we describe a new species of Demodex. This new species is the fifth valid Demodex species recorded from primates.

Trichinella T9 in wild bears in Japan: Prevalence, species/genotype identification, and public health implications

In Japan, the recent series of sporadic outbreaks of human trichinellosis caused by Trichinella (Nematoda: Trichocephalida) has occurred owing to the consumption of raw or insufficiently cooked meat from wild bears. However, the infection status and molecular characteristics of Trichinella larvae in Japanese wild bears remain poorly understood. This study investigated the prevalence of Trichinella spp. in brown bears (Ursus arctos) from Hokkaido, and Japanese black bears (Ursus thibetanus japonicus) from three prefectures (Aomori, Akita, and Iwate) in northern Japan, between April 2019 and August 2022. Trichinella larvae were detected in 2.5% (6/236) of the brown bears and 0.9% (1/117) of the Japanese black bears. Sequence analysis using two genetic loci, the internal transcribed spacer region of nuclear ribosomal DNA and the mitochondrial cytochrome c oxidase subunit I gene, revealed that the larvae collected from the seven infected bears were identical to one of the two haplotypes of Trichinella T9. The prevalence of Trichinella T9 is low but is maintained in bears in the Hokkaido and Iwate prefectures suggesting that undercooked meat from these animals could cause human infection. Thus, continued health education campaigns are needed to raise awareness of the potential risk of trichinellosis among hunters, meat suppliers, consumers, and local governmental health agencies.

Molecular characterization of oriental eyeworm (Thelazia callipaeda) detected from raccoon (Procyon lotor) and Japanese raccoon dog (Nyctereutes viverrinus) in Kanto region, Japan

BACKGROUND

The oriental eyeworm Thelazia callipaeda (Spirurida: Thelaziidae) is an emerging parasitic ocular nematode of carnivores and humans. In domestic animals and humans, the infection causes varying degrees of inflammation and lacrimation, and wild carnivores represent an important reservoir. In this study we examined the infection status and molecular characterization of T. callipaeda in two urban carnivores, raccoons Procyon lotor and wild Japanese raccoon dogs Nyctereutes viverrinus, in the Kanto region of Japan.

METHODS

From January 2020 to December 2021, 193 carcasses including 178 raccoons and 15 raccoon dogs were examined for the presence of worms in the eye. The worms from infected animals (one worm per host) were morphologically identified as T. callipaeda. Worms (1-5 worms per host) were subjected to genetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences.

RESULTS

The prevalence of T. callipaeda in raccoons and Japanese raccoon dogs was 20.2% (36/178) and 13.3% (2/15), respectively. The cox1 sequences from 56 worms from 38 animals revealed three haplotypes (h9, h10, and h12). Analysis of multiple worms for five raccoons showed co-infection of two different haplotypes (h9 and h10) in a single host. Comparing our data with published sequences, three sequences obtained from raccoons and raccoon dogs shared the same haplotypes as those reported in humans, dogs, and cats in Japan.

CONCLUSIONS

Our findings show a high prevalence of T. callipaeda in raccoons, suggesting that this invasive carnivore species serves as an important natural reservoir of T. callipaeda in the Kanto region of Japan, an area with the highest human population of the country.

Three new species of Eimeria (Apicomplexa: Eimeriidae) from the Amami rabbit, Pentalagus furnessi (Mammalia: Leporidae)

The Amami rabbit, Pentalagus furnessi (Mammalia: Lagomorpha: Leporidae), is a relict and endangered species endemic to the Amami-Oshima and Tokunoshima Islands, located in southwestern Japan. Here, we described three new species of Eimeria (Apicomplexa: Eimeriidae) parasites detected from fecal samples of wild Amami rabbits. Eimeria furnessi n. sp., recorded in 21 (58.3%) samples, has ellipsoidal oocysts with two walls and micropyle, 26.0 × 16.6 μm, and elongate-ovoidal sporocysts, 13.1 × 6.3 μm, with Stieda body. Eimeria hilleri n. sp., recorded in 9 (25.0%) samples, has ellipsoidal oocysts with two walls and micropyle, 34.7 × 21.4 μm, and elongate-fusiform to elongate-ovoidal sporocysts, 15.7 × 8.3 μm, with Stieda and substieda bodies. Eimeria sagentae n. sp., recorded in 13 (36.1%) samples, has ellipsoidal oocysts with two walls and micropyle, 20.9 × 14.5 μm, and elongate-ovoidal sporocysts, 10.4 × 5.0 μm, with Stieda body. The three new species can be distinguished by the size and color of their oocysts. Further studies related to the pathogenicity of these parasites can improve the breeding and propagation procedures of the Amami rabbit.

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Amami rabbit, Pentalagus furnessi, only can be found on two small islands in Japan.

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Eimeria spp. detected in fecal samples underwent morphological studies.

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New species were defined as Eimeria furnessi, E. hilleri, and E. sagentae.

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The three new species can be distinguished by their oocysts size and color.

Detection and characterization of Hyaloklossia kasumiensis (Apicomplexa: Sarcocystidae) from Nagoya Daruma pond frog, Pelophylax porosus brevipodus

The Nagoya Daruma pond frog (Pelophylax porosus brevipodus) is an endangered anuran species endemic to the semi-aquatic environment of Japan. On June 11, 2021, four of the six Nagoya Daruma pond frogs captured from the wild and kept in an aquarium died in rapid succession. Pathological and/or parasitological examinations of two of the four carcasses revealed protozoan infection in their kidneys. The pathogen identified as Hyaloklossia kasumiensis (Apicomplexa: Sarcocystidae: Hyaloklossiinae) based on their morphological and molecular characterization. This is a new host record of H. kasumiensis. Mitochondrial cox1 sequence analysis suggest that the present species detected from Nagoya Daruma pond frog belongs to the same lineage as those found in the Tokyo Daruma pond frog (P. p. porosus) from Ibaraki Prefecture, Japan. This particular lineage may be prevalent among Pelophylax porosus ssp. distributed in Japan.

Subcutaneous cysticercosis due to Taenia crassiceps (Cestoda: Taeniidae) in an imported steppe lemming in Japan

This study describes a subcutaneous proliferative cysticercosis in a pet steppe lemming, Lagurus lagurus (Rodentia: Cricetidae), bred and imported from Czech Republic into Japan. Numerous metacestodes were collected from the subcutaneous cystic lesion of the left medial thigh. Four surgical removals were coupled with anthelmintic treatment but ended with recurrence. Based on morphological features and mitochondrial DNA sequences, the metacestodes were identified as the larval stage of Taenia crassiceps (Zeder, 1800). This is the first case of infection with larval T. crassiceps in rodents of the genus Lagurus, and becomes the third case of the parasite detected from imported animals in Japan. Related public health concerns are discussed.

Haemoproteus columbae infection in a straggler racing pigeon sheltered in Japan

A racing pigeon (Columba livia var. domestica), a straggler from Taiwan, was sheltered in Nara Prefecture, Japan in 2020. This pigeon showed hemolysis and elevated levels of hepatobiliary and muscle enzymes. Gametocytes of Haemoproteus columbae (Apicomplexa: Haemosporida) were observed within the host erythrocytes in thin blood smears. A partial sequence of the mitochondrial cytochrome b gene amplified from blood DNA was identical to the lineage HAECOL1 previously reported from pigeons worldwide. This is the first record of H. columbae infection in a sheltered bird in Japan.

Genetic characterization of Trichomonas gallinae (Rivolta, 1878) in companion birds in Japan and the genotypical relationship in the Asia region

BACKGROUND/PURPOSE

Avian trichomonosis is a parasitic infection that affects a wide range of avian species, including free-ranging and pet birds worldwide, and Trichomonas gallinae has been considered as the only causative agent for decades. The sequence of the 5.8S ribosomal RNA with internal transcribed spacer (ITS) regions was widely used for identifying genotypes and determining inter-specific and intra-specific diversity. Moreover, the sequence of Fe-hydrogenase (FeHyd) was proposed as the second genetic marker for providing improved resolution of strain subtyping discrimination. Though the correlation between genetic variability and strain virulence is controversial, FeHyd analyses seemed to be useful to investigate the host or geographic origin of isolates. This study aimed to investigate the genetic characteristics of avian Trichomonas spp.

METHODS

Forty-seven oral swabs and crop lavage fluids were collected from 9 avian genera, which were diagnosed as Trichomonas-positive by microscopy in animal hospitals in Japan, were analyzed.

RESULTS

Genetic analysis of clonal isolates revealed the prevalence of the single genotype, ITS-OBT-Tg-1, by ITS region analysis, while two different subtypes, A2 and novel A3, were suggested by FeHyd gene analysis among Japanese companion birds. Phylogenetic analyses of available ITS sequences obtained from the Asia region (China, Iran, Iraq, and Saudi Arabia) were also preformed, revealing endemic ITS-OBT-Tg-1, ITS-OBT-Tg-2, ITS-OBT-Ttl-1, genotype III, and Saudi Arabia's unique lineages. Furthermore, ITS-OBT-Tg-2 predominance in these countries indicates different strains origination from Japan.

CONCLUSION

This is the first report of the genetic characterization of T. gallinae in Japan with discovery of novel subtype A3.

Hyaloklossia Labbé, 1896 (Alveolata: Apicomplexa) in frogs: Description of a new species and proposing a new subfamily to accommodate these enigmatic parasites

Hyaloklossia Labbé ,1896 (Alveolata: Apicomplexa) is a monotypic genus of renal coccidia found in anurans, particularly in the edible frog Pelophylax kl. esculentus (Amphibia: Anura: Ranidae), distributed in different parts of Europe. Here we propose a new Hyaloklossia species from the Tokyo daruma pond frog, Pelophylax porosus porosus. The coccidium detected in the renal tissue of P. p. porosus shared some morphological characteristics with the type species, Hyaloklossia lieberkuehni (Labbé, 1894), reported from P. kl. esculentus. However, in addition to size differences in several oocyst and sporocyst features between these parasites, phylogenetic analysis of gene fragments from two nuclear ribosomal loci and the mitochondrial cytochrome c oxidase subunit 1, exposed distinct genetic differences between H. lieberkuehni and our new species. Although our analysis validated the monophyly of Hyaloklossia with some members of the Toxoplasmatinae Biocca, 1957, Cystoisosporinae Frenkel et al., 1987, and Eumonosporinae Chou et al., 2021 (Sarcocystidae Poche, 1913), comparison of genetic differences between Hyaloklossia species from P. p. porosus and H. lieberkuehni revealed the presence of a greater number of polymorphisms than that observed when comparing inter-species (Heydornia spp., Besnoisita spp.) or inter-genus (Toxoplasma vs. Neospora, Neospora vs. Hammondia, and Neospora vs. Heydornia) variabilities among members of the Sarcocystidae. This indicates that Hyaloklossia, as re-erected and defined by Modrý et al. (2001, Int. J. Syst. Evol. Microbiol. 51, 767–772), with its homoxenous life cycle, requires placement in its own subfamily. Thus, we propose a new subfamily, Hyaloklossiinae n. subfam., to accommodate two species, H. lieberkuehni from Europe and Hyaloklossia kasumienesis n. sp. which we describe here from P. p. porosus in Japan.

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Hyaloklossia was detected from the kidney of Pelophylax porosus porosus (Amphibia: Anura).

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The species was described as Hyaloklossia kasumiensis n. sp.

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This is a new host record for Hyaloklossia and also the first report in Asia.

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Hyaloklossiinae, was proposed as a new subfamily in the Sarcocystidae.

Theileria infection with severe anemia and unhealed fracture in a sika deer Cervus nippon aplodontus (Cervidae: Cetartiodactyla)

An adult female sika deer (Cervus nippon aplodontus) inhabiting Nara Park, Nara, Japan, had broken bone injuries from a car accident. During its treatment, we found that the sika deer had severe anemia and the fracture remained unhealed throughout. Peripheral blood smear revealed piroplasms in the erythrocytes, which were identified as merozoites of undescribed Theileria species, widely found in sika deer in Japan. This is the report of a clinical case of Theileria infection, accompanied by severe anemia in a sika deer.

Detection of Eumonospora henryae (Apicomplexa: Sarcocystidae) from Falco columbarius (Falconiformes: Aves): Comparison of host-parasite phylogram and comments on the family Sarcocystidae Poche, 1913

The genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), an avian coccidia, is characterized by monosporocystic and octasporozoic oocysts without Stieda and substieda bodies. Some members of Eumonospora, which infect several raptor species, exhibit high levels of pathogenicity, making eumonosporiosis the leading cause of death in captive-bred raptors. The host specificity of these species appears to be mesostenoxenous, as evidenced by unsuccessful transmission between different orders of avian hosts. However, several studies have detected Eumonospora spp. in taxonomically distant avian hosts, indicating that some of these species may be euryxenous. In the current study, diarrheic fecal examination of a captive-bred juvenile merlin (Falconiformes: Aves) in Tokyo, Japan, was conducted, and a large number of oocysts were morphologically and molecularly identified as E. henryae (Yakimoff and Matschulsky, 1932), a coccidia species reported only in Strigiformes. This is a new recorded host for this coccidia. Phylogenetic analyses via Bayesian inference and maximum likelihood methods using concatenated genomic datasets consisting of nuclear 18S rDNA, nuclear 28S rDNA and mitochondrial cytochrome C oxidase subunit 1 gene, revealed a well-supported monophyletic clade of Eumonospora spp. belonging to the family Sarcocystidae Poche 1913, which largely corresponded to the avian host phylogram. Therefore, based on distinguishable oocyst morphology, a new subfamily, Eumonosporinae, within the family Sarcocystidae, is proposed, and a reconsideration of the definition of Sarcocystidae is suggested. Further molecular characterization of this emerging pathogen, as well as clarification of its complete life cycle, including cyst-forming ability, is required for more appropriate generic assessment.

Three new Prototapirella species, Opisthotrichum janus, and Troglocorys cava add to Entodiniomorphida (Ciliophora, Trichostomatia) diversity in mountain gorillas in Rwanda

Recently, a high number of Entodiniomorphida species was discovered in Virunga mountain gorillas (Gorilla beringei beringei) in Rwanda compared to other primates. Thirteen species of five genera (Troglocorys, Gorilloflasca, Prototapirella, Troglodytella, and Opisthotrichum) were identified with 10 species in Gorilloflasca, Prototapirella, and Troglodytella being host-specific, to our current knowledge. The remaining three species have been described for other herbivorous mammals; Prototapirella gorillae for western lowland gorillas; Troglocorys cava for western lowland gorillas, chimpanzees, and guinea baboons; Opisthotrichum janus in the family Ophryoscolecidae is regarded as specific to African antelopes. Here, we show the first indication that wild herbivorous hindgut fermenting mammals might have rumen ophryoscolecids in the intestine sympatric with their native intestinal ciliates. We also describe three new Prototapirella species, P. sabyinyo, P. sulcata, and P. curiosa. The somatic ciliary zones of the three new species are atypical of Prototapirella while their buccal infraciliature is not different from that of other Prototapirella species.

First record of infestation of a pet sloth in Japan with the exotic tick Amblyomma geayi (Acari: Ixodidae)

On December 11, 2018, a single unengorged adult tick was found on the body surface of the trunk of an imported wild-caught Linnaeus's two-toed sloth (Choloepus didactylus) during a routine health check in an animal clinic in Tokyo, Japan. The tick was identified as Amblyomma geayi based on the morphological and molecular characteristics. This is the first case of the introduction of an Amblyomma species to Japan via an imported pet sloth. The present study highlights the current loopholes in Japan's regulatory system for animal imports.

Resurrection of the genus Eumonospora (Apicomplexa: Sarcocystidae) for Caryospora species without Stieda body

The coccidian genus Eumonospora Allen, 1933 is re-established. Despite morphological features and host preference among species, coccidian with octasporozoic and monosporocystic oocysts are traditionally consider to belonging in the genus Caryospora Léger, 1904 (Apicomplexa: Eimeriidae). Recently, the genus Avispora Schuster et al., 2016 was proposed for above caryosporoids parasitizing birds based on combined morphological and phylogenetic analyses. However, diagnostic morphological characters of the genus Avispora, the absence of Stieda and substieda bodies, has already been mentioned in the description of the genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), and thus Avispora is considered to be a junior synonym of Eumonospora. In this study, caryosporoid coccidians were detected from five owl species; Bubo scandiacus, Ptilopsis leucotis, Athene noctua, Strix nebulosa, and Pulsatrix perspicillata (Strigiformes: Strigidae) and identified as Avispora henryae (Yakimoff & Matikaschwaili, 1932) described from Bubo bubo (Strigiformes: Strigidae). Eumonospora henryae (Yakimoff & Matikaschwili, 1932) comb. nov. is redescribed for this species based not only on morphological features but also on phylogenetical analyses. The key of the genus Eumonospora and a list to the species known at present are also provided.

Alien parasitic infections in the endangered Ryukyu long-furred rat (Diplothrix legata) on Amami-Oshima Island, Japan

There is limited knowledge about parasites of the endangered Ryukyu long-furred rat, Diplothrix legata (Murinae, Rodentia) endemic to Okinawa, Tokunoshima, and Amami-Oshima Islands in Japan. In the present study, postmortem histopathological examination of an individual found on Amami-Oshima Island revealed a mixed helminth infection of Calodium hepaticum, Hydatigera taeniaeformis, and Angiostrongylus cantonensis. These helminths are considered non-native to Amami-Oshima Island and are maintained by invasive mammals, such as non-native rats and outdoor cats. This observation presents a new host record for C. hepaticum and H. taeniaeformis and the first record of A. cantonensis in Ryukyu long-furred rat on Amami-Oshima Island.

Detection and molecular characterization of Cryptosporidium species in wild-caught pet spiny-tailed lizards

Uromastyx is a genus of the herbivorous agamid lizards, also known as spiny-tailed lizards or mastigures, which are found in parts of Africa and the Middle East. Currently, several species of this genus are available in the international pet trade in Japan. In this study, two imported wild-caught spiny-tailed lizards (Arabian blue mastigure, Uromastyx ornata philbyi, and Sudan mastigure, Uromastyx dispar flavifasciata) were diagnosed with a Cryptosporidium (Apicomplexa: Cryptosporidiidae) infection based on the presence of the oocysts in the rectal feces using sucrose flotation and light microscopy examination at a local animal hospital in Tokyo, Japan. One of the lizards had died, and histopathological examination revealed enteritis with the Cryptosporidium parasite. Sequence analyses using the small subunit ribosomal RNA, actin, and 70-kDa heat shock protein genes indicated that the lizards had contracted a novel variant of C. avium that commonly infects avian species.

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Two pet wild-caught spiny-tailed lizards exhibited gastrointestinal symptoms.

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Lizards were both infected with a novel Cryptosporidium avium variant.

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First detection of avian-associated Cryptosporidium species in the family Agamidae.

Neospora caninum antigens displaying virus-like particles as a bivalent vaccine candidate against neosporosis

Neospora caninum is a causative and transmissible agent of dog and bovine neosporosis. The resulting reproductive failures in infected cattle lead to significant economic losses worldwide. However, there is no satisfactory treatment or vaccine currently available to combat this pathogen. Thus, the development of appropriate vaccines to manage its infection and transmission is urgently needed. In this study, we expressed Rous sarcoma virus-like particles (RSV-LP) that displayed dual N. caninum antigens in silkworms. The antigen candidates are modified by adding a transmembrane domain of GP64 protein from Bombyx mori nucleopolyhedrovirus (BmNPV) to the C-terminus of surface antigen 1 (NcSAG1) and SAG1-related sequence 2 (NcSRS2). The NcSRS2 alone or the NcSAG1/NcSRS2 bivalent form displaying RSV-LPs were purified using sucrose density gradient centrifugation. These purified VLPs were then used for immunizations in gerbils, Meriones unguiculatus, to evaluate the anti-N. caninum effects in vivo. The results demonstrated that antigens displaying RSV-LPs in immunized gerbils produced the antigen-specific antibody, leading to a relatively lower parasite load after infections of N. caninum. To the best of our knowledge, this is the first study to present an RSV-LP vaccine displaying bivalent antigens from neosporosis. Taken together, our strategy suggests that silkworm-expressed virus-like particles (VLPs) are promising bivalent vaccine candidates against N. caninum infections.

Toxoplasma gondii infection in Amami spiny rat on Amami-Oshima Island, Japan

The Amami spiny rat (Tokudaia osimensis) is an endangered rodent species that is endemic to the forests of Amami-Oshima Island, Kagoshima, Japan. In July 2018, a deceased adult male Amami spiny rat was found on the Yuwandake Mountain Trail on the south-central coast of Amami-Oshima Island. Histopathological observations revealed protozoan infections in the liver, lungs, and heart. Nested or semi-nested PCRs targeting the B1, SAG3, GRA6, and ROP18 genes successfully detected the genomic DNA of Toxoplasma gondii in the formalin-fixed and paraffin-embedded specimen. Sequence analyses of the SAG3, GRA6, and ROP18 genes suggested that the strain detected in the study specimen was related to the type II strain of T. gondii. This is the first confirmed case of T. gondii infection in an Amami spiny rat.

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A deceased Amami spiny rat was diagnosed with disseminated toxoplasmosis.

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We present the first case report of T. gondii infection in the Amami spiny rat.

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Feral cat populations require control to avoid the spread of T. gondii infection.

Molecular and histopathological features of Cryptosporidium ubiquitum infection in imported chinchillas Chinchilla lanigera in Japan

Long-tailed chinchillas Chinchilla lanigera are popular rodent species kept both in households, where they are hand-raised as pets, and in zoological facilities. From January 2016 to February 2017, 13 juvenile chinchillas from five facilities in Japan were diagnosed with cryptosporidiosis at the animal hospital. Eight of the cases were fatal. All of the animals were imported from the Czech Republic by the same vendor. Histopathological and multilocus sequence analyses using 18S ribosomal RNA, actin, 70-kDa heat shock protein, and 60-kDa glycoprotein genes confirmed Cryptosporidium ubiquitum of subtype XIId as the etiological agent. Multilocus analysis demonstrated the presence of two new sequence types closely related to the C. ubiquitum Xlld strain isolated from a human in the USA. This study indicated that potentially zoonotic Cryptosporidium is widespread and may have caused a high number of deaths among imported juvenile chinchillas.

Morphological and molecular characterization of Cystoisospora sp. from Asian small-clawed otters Aonyx cinereus

In this study, we provide the first description of Cystoisospora infection in Asian small-clawed otters (Aonyx cinereus). In July 2017, three juvenile otters recently imported from the Republic of Indonesia showed severe diarrhea and were diagnosed with coccidial infection; two of them eventually died. Fecal examination revealed the presence of numerous oocysts. Sporulated oocysts showed typical Cystoisospora features, measuring 24.6 ± 1.6 (22.0–27.0) × 21.8 ± 1.4 (19.0–25.0) μm, with an oocyst length/width ratio of 1.1 ± 0.1 (1.0–1.3). Each sporocyst contained four sporozoites in a head-to-tail arrangement. The Stieda body was absent, and the sporocyst residuum was present. These morphological characteristics differentiated this species from the other valid Cystoisospora species described from mustelids. Molecular analysis was conducted at two loci: the nuclear 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I genes. The 18S sequence showed high similarity with canine Cystoisispora ohioensis (1-bp difference, 1422/1423 [99.9%]). At the cytochrome c oxidase subunit I gene locus, the sequence from otters was identical to that of feline Cystoisospora rivolta (847/847 [100%]). Phylogenetic analyses using concatenated data demonstrated that Cystoisospora sp. from otters and C. rivolta grouped together in the same Cystoisospora clade. Based on these data, we concluded that Cystoisospora sp. detected from otters appeared to be highly similar to C. rivolta.

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We characterized Cystoisospora infection in three Asian small-clawed otters.

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Two otters showed anorexia, green diarrhea, and vomiting.

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Fecal examination revealed numerous oocysts with typical Cystoisospora features.

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Sporulated oocysts were morphologically differentiated from those of other Cystoisospora spp. from mustelids.

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Molecular and morphological features were highly similar to feline C. rivolta.

Larva Migrans of Baylisascaris potosis In Experimental Animals

Occurrence of clinical signs by infection with Baylisascaris potosis, the roundworm of kinkajous ( Potos flavus), in mice, rats, and rabbit were studied, and the migration behavior of larvae in mice were compared with that of Baylisascaris transfuga, the roundworm of bears ( Ursus spp.). Three groups of 8 mice, 3 groups of 6 rats, and 3 groups of 2 rabbits were inoculated with either 10, 100, or 1,000 B. potosis eggs. The other 8 mice were inoculated with 1,000 B. transfuga eggs. Animals were monitored for the occurrence of clinical signs until 60 days postinoculation (DPI). The carcass, viscera, brain, and eyes of each of 6 mice inoculated with 1,000 eggs of B. potosis or B. transfuga at 60 DPI were removed individually, and the number of larvae was counted. One mouse inoculated with 100 B. potosis eggs showed rolling at 27 DPI, and 1 larva was found in the medulla oblongata of this mouse. No clinical signs were observed in the other mice or in the rats and rabbits. A mean of 387.2 larvae was recovered from mice inoculated with 1,000 B. potosis eggs, and a mean of 422.0 larvae from mice inoculated with 1,000 B. transfuga eggs. The highest number of larvae was recovered from the carcasses for both B. potosis and B. transfuga. In the viscera, higher numbers of B. transfuga larvae (mean 131.8) were seen than B. potosis larvae (mean 33.1). In the brain, only 1 larva was detected in 1/6 mice inoculated with 1,000 B. potosis eggs, whereas a mean of 21 larvae was detected in mice inoculated with 1,000 B. transfuga eggs. A few larvae (range 0-1) were detected in the eyes of both mice inoculated with B. potosis or B. transfuga eggs. The result indicated that B. potosis larvae do not show a higher tendency to migrate into the brain of mice than B. transfuga larvae. However, 1 mouse inoculated with 100 eggs had 1 larva in the central nervous system and showed a serious neurological sign. This result may underline a potential risk of B. potosis to cause neural larva migrans in humans.

First report of fatal disseminated microsporidiosis in two inland bearded dragons Pogona vitticeps in Japan

Introduction.Encephalitozoon pogonae is a newly described pathogen belonging to the phylum Microsporidia. In Austria and the USA, this species has been isolated from fatal and disseminated cases of captive-bred inland bearded dragons. Here, we report the case of fatal disseminated microsporidiosis caused by E. pogonae in two bearded dragons in Japan. Case Presentation. The two lizards from different private households in Tokyo, Japan, had been brought to an animal hospital for examination. In both cases, the animal presented with a history of weight loss for several weeks. There were no improvements in clinical symptoms and the lizards deteriorated and finally died. Histopathological examination demonstrated necrotizing granulomatous inflammation attributed to disseminated microsporidian infection. Nucleotide sequencing of the nuclear ribosomal internal transcribed spacer region identified the microsporidian as E. pogonae with sequence identity of 100 %. Conclusion. We report the first case, to our knowledge, of disseminated microsporidiosis caused by E. pogonae in inland bearded dragons in Japan. Although it is difficult to diagnose prenatally since the signs are nonspecific, the disease should be considered in the differential diagnosis of chronic infections that do not respond to antibiotics.

Isospora lunaris n. sp. (Apicomplexa: Eimeriidae) from the domestic Java sparrow in Japan

Five individuals of the domestic Java sparrows, Lonchura oryzivora (Aves: Estrildidae), were examined for coccidian parasites. Sporulated oocysts had two sporocysts containing four sporozoites each. Sporulated oocysts (n=30) were spherical, with a two splinter-like polar granules. Oocyst size was 22.1×20.7 (20.0-25.0×20.0-22.5)μm. They had a thick wall that consisted of a pale yellow outer layer and a dark yellow inner layer, and lacked micropyle and residuum. Sporocysts (n=60) were elongated ovoid 14.1×9.8 (12.5-15.0×7.5-10.0)μm, smooth walled, and colorless, with crescent-shaped Stieda and indistinct substieda bodies. Sporocyst residuum was interspersed between sporozoites. Sporozoites were oriented transverse to the sporocyst longitudinal axis. On the basis of morphological data, the species isolated in the present study is a new species of Isospora and propose the name Isospora lunaris n. sp.

Ranavirus in an outbreak of dermatophilosis in captive inland bearded dragons (Pogona vitticeps)

BACKGROUND

Various pathogens cause skin diseases in lizards. An outbreak of skin disease occurred in a population of 100 inland bearded dragons at a breeding facility in Japan; 50 developed skin lesions and 15 mortalities were reported.

HYPOTHESIS/OBJECTIVES

To identify the pathogens responsible for the skin lesions and to determine the cause of death.

ANIMALS

Eight specimens (three dead, two euthanized, three living) were randomly selected from a group of inland bearded dragons with skin lesions consisting of multifocal superficial dermatitis.

METHODS

Biopsy samples were taken from skin lesions and healthy skin of the live specimens. Postmortem examinations were performed on the dead and euthanized specimens. Skin samples were processed for microbiological culture, 16S ribosomal DNA (rDNA) sequencing for bacteria, ranavirus major capsid protein (MCP) gene sequencing and histopathological examination. Histopathological examinations were also performed on postmortem tissue samples.

RESULTS

Both Austwickia chelonae and ranavirus (DNA) were detected in the skin lesions. Pathological examination revealed no significant visceral lesions caused by A. chelonae or ranavirus infection in dead specimens.

CONCLUSIONS AND CLINICAL IMPORTANCE

To the best of the authors' knowledge this is the first report of dermatophilosis due to A. chelonae infection in lizards and the first description of a concurrent infection with a ranavirus. The combined infection associated with the skin lesions may have been the primary cause of death. Co-infection with a ranavirus should be considered as a possible factor in cases of reptilian dermatophilosis.

Prevalence of Baylisascaris Roundworm in Captive Kinkajous in Japan

Baylisascaris potosis causes larva migrans in animals. The present study evaluated the prevalence of B. potosis in captive kinkajous ( Potos flavus ) and the ability of milbemycin to treat natural infections of B. potosis in 2 female wild-caught kinkajous. In 2012, fecal samples were collected from 16 kinkajous in 6 zoological gardens and 29 imported captive kinkajous from 4 pet traders in Japan. Although all samples from zoological gardens were negative, 8 kinkajous from traders were positive for Baylisascaris eggs, at least 4 of which were wild caught in the Republic of Guyana. No associated human illness was reported from any of the facilities. The 2 infected kinkajous received a single oral administration of Milbemycin® A Tablets, which delivers 0.69-0.89 mg/kg milbemycin oxime. Fecal examinations on days 14 and 30 were negative for Baylisascaris eggs. These results demonstrated that milbemycin oxime has possible anthelmintic efficacy against Baylisascaris roundworms in captive kinkajous. We conclude that Baylisascaris infections are highly prevalent in wild-caught kinkajous in Japan and that most of the infected kinkajous were imported from the Republic of Guyana.

Oxalate nephropathy in free-living American bullfrog tadpoles

In February 2014, wild American bullfrog Lithobates catesbeianus tadpoles from an artificial pond in the Kyusyu region, Japan, presented with coelomic and subcutaneous edema and erythema within the skin. A pathological examination of 57 tadpoles of American bullfrogs in the region was conducted to evaluate the disease. Crystal deposition of varying degrees was found in the kidneys of 35 tadpoles (61.4%). The crystals were transparent, pleomorphic in shape, highly birefringent in polarized light, and arranged in a radial pattern within the renal tubular lumen. Using Alizarin Red S stain and liquid chromatography, these crystals were identified as calcium oxalate. Severe coelomic and subcutaneous edema was observed in 7 of these 35 tadpoles (20.0%). Ammonia levels in coelomic fluid were extremely elevated (>1000 µg dl(-1)) in 4 tadpoles examined. These findings suggest that oxalate deposition in kidneys causes metabolic disorder with renal nephropathy. The source of the oxalate could not be determined; however, the presence of calcium oxalates in pond sediments, as revealed by liquid chromatography, suggested that the deposition was most likely due to ingestion of oxalate materials from the environment. This is the first report of oxalate nephropathy in free-living amphibians.

Effects of chronic γ-irradiation on growth and survival of the Tohoku hynobiid salamander, Hynobius lichenatus

The Tohoku hynobiid salamanders, Hynobius lichenatus, were chronically irradiated with γ-rays from embryonic to juvenile stages for 450 days. At 490 μGy h(-1) or lower dose rates, growth and survival were not significantly affected by irradiation, and any morphological aberrations and histological damages were not observed. At 4600 μGy h(-1), growth was severely inhibited, and all the individuals died mostly at the juvenile stage. Chronic LD50 was 42 Gy as a total dose. In the liver, the number of hematopoietic cells was significantly reduced in the living juveniles, and these cells disappeared in the dead juveniles. In the spleen, mature lymphocytes were depleted in the living larvae, and almost all the heamtopoietic cells disappeared in the dead juveniles. These results suggest that this salamander died due to acute radiation syndrome, i.e., hematopoietic damage and subsequent sepsis caused by immune depression. The death would be also attributed to skin damage inducing infection. At 18,000 μGy h(-1), morphological aberrations and severe growth inhibition were observed. All the individuals died at the larval stage due to a multiple organ failure. Chronic LD50 was 28 Gy as a total dose. Assuming that chronic LD50 was 42 Gy at lower dose rates than 4600 μGy h(-1), a chronic median lethal dose rate could be estimated to be <340 μGy h(-1) for the whole life (>14 years). These results suggest that, among guidance dose rates, i.e., 4-400 μGy h(-1), proposed by various organisations and research programmes for protection of amphibians and taxonomic groups or ecosystems including amphibians, most of them would protect this salamander but the highest value may not on the whole life scale.

Experimental infection of Mongolian gerbils with Baylisascaris potosis

The present study evaluated the pathogenicity of Baylisascaris potosis, a newly described ascarid nematode, in Mongolian gerbils. Gerbils were infected with varying doses of either B. potosis or Baylisascaris transfuga embryonated eggs (100, 1,000, and 4,000) for 30 days postinfection (pi). Baylisascaris potosis-infected gerbils showed no clinical signs of disease; however, gerbils exposed to 1,000 and 4,000 B. transfuga eggs showed severe neurologic signs at 22-29 days and 14-15 days pi, respectively. Histopathologic examination revealed larvae and lesions in the intestine, lung, liver, and muscles of B. potosis-infected gerbils, but not in the brain, whereas B. transfuga larvae were found only in the brain and muscle. These results indicate that B. potosis larvae migrate through numerous organs and are associated with visceral larva migrans in gerbils, but less frequently migrate to the nervous system in gerbils than does B. transfuga .

Molecular genotyping of anisakis larvae in Middle Eastern Japan and endoscopic evidence for preferential penetration of normal over atrophic mucosa

BACKGROUND

Anisakiasis is a parasitic disease caused primarily by Anisakis spp. larvae in Asia and in Western countries. The aim of this study was to investigate the genotype of Anisakis larvae endoscopically removed from Middle Eastern Japanese patients and to determine whether mucosal atrophy affects the risk of penetration in gastric anisakiasis.

METHODS

In this study, 57 larvae collected from 44 patients with anisakiasis (42 gastric and 2 colonic anisakiasis) were analyzed retrospectively. Genotyping was confirmed by restriction fragment length polymorphism (RFLP) analysis of ITS regions and by sequencing the mitochondrial small subunit (SSU) region. In the cases of gastric anisakiasis, correlation analyses were conducted between the frequency of larval penetration in normal/atrophic area and the manifestation of clinical symptoms.

RESULTS

Nearly all larvae were A. simplex seusu stricto (s.s.) (99%), and one larva displayed a hybrid genotype. The A. simplex larvae penetrated normal mucosa more frequently than atrophic area (p = 0.005). Finally, patients with normal mucosa infection were more likely to exhibit clinical symptoms than those with atrophic mucosa infection (odds ratio, 6.96; 95% confidence interval, 1.52-31.8).

CONCLUSIONS

In Japan, A. simplex s.s. is the main etiological agent of human anisakiasis and tends to penetrate normal gastric mucosa. Careful endoscopic examination of normal gastric mucosa, particularly in the greater curvature of the stomach will improve the detection of Anisakis larvae.

The first genetically confirmed case of Dioctophyme renale (Nematoda: Dioctophymatida) in a patient with a subcutaneous nodule

We describe a nematode larva in a subcutaneous nodule excised from a 44-year-old Chinese male who had been living in Japan for 15 years. Morphological features suggested that the worm was a dioctophimatid nematode. PCR amplification and sequencing of small subunit ribosomal DNA and mitochondrial cytochrome subunit c oxidase genes allowed us to identify the larva as the giant kidney worm, Dioctophyme renale (Goeze, 1972). This is the first molecularly confirmed human case of a dermal D. renale infection.

First report of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) infections in invasive rodents from five islands of the Ogasawara Archipelago, Japan

BACKGROUND

Angiostrongylus cantonensis (Chen, 1935) is a parasite of murid rodents and causative agent of human neuro-angiostrongyliasis. In 2011, the Ogasawara Islands in the western North Pacific were assigned a World Natural Heritage site status. The occurrence of A. cantonensis is well documented in the Chichijima, Hahajima, and Anijima Islands. However, the occurrence of A. cantonensis in the other islands of the Ogasawara Islands has not been reported.

METHODOLOGY/PRINCIPAL FINDINGS

Between March 2010 and July 2011, 57 Rattus norvegicus and 79 R. rattus were collected from 9 islands (the Hahajima group: Anejima, Imoutojima, Meijima, Mukohjima, and Hirajima; Chichijima group: Minamijima; Mukojima group: Nakoudojima and Yomejima; and Iwojima group: Iwojima). Adult nematodes were found in the pulmonary artery of 46 R. norvegicus collected in the 5 islands of the Hahajima group (Anejima, Meijima, Imoutojima, Hrajima, and Mukohjima Islands). These nematodes were identified by molecular analysis as A. cantonensis. Comparison of the mitochondrial DNA sequences confirmed that all the samples from the Ogasawara Islands shared only a single lineage of A. cantonensis, which has been previously detected in the Okinawa, Hawaii, and Brazil.

CONCLUSIONS/SIGNIFICANCE

We describe new endemic foci of rat angiostrongyliasis in the Hahajima group (Anejima, Meijima, Imoutojima, Hirajima, and Mukohjima Islands) of the Ogasawara Islands. These findings indicate that the endemic foci of A. cantonensis are widely distributed in the Ogasawara Islands. Although human cases have not yet been reported in the Ogasawara Islands, the widespread detection of A. cantonensis could be of importance from the perspective of public health.

Multilayer rat hepatocyte aggregates formed on expanded polytetrafluoroethylene surface

Feasibility of using a macroporous membrane material, expanded polytetrafluoroethylene (ePTFE), for culturing hepatocytes on its surface was examined. Adult rat hepatocytes were attached to an ePTFE surface and cultured in a hormonally defined medium supplemented with or without fetal calf serum (FCS, 10%) or bovine serum albumin (BSA, 0.03-3%). When cultured in a FCS-suplemented medium, hepatocytes reorganized themselves into multilayer cell aggregates on an ePTFE surface. The morphological characteristics of hepatocytes were influenced by the modification of the ePTFE surface as well as the culture medium. Hepatocytes cultured on a polyvinylalcohol (PVA)-coated ePTFE surface formed many more multilayer cell aggregates than those cultured on an uncoated ePTFE surface. Such highly multilayered hepatocyte aggregates were also noted when the cells were cultivated in a BSA-supplemented medium. On the other hand, when cultured in a FCS- or BSA-free medium, hepatocytes formed cell monolayers on both PVA-coated and uncoated ePTFE surfaces as did the cells on a collagen-coated polystyrene surface. The hepatocytes in the aggregates exhibited high albumin expression capability and low DNA synthesis rate as compared with those in monolayer cultures. The multilayer hepatocyte aggregates, as immobilized on a PVA-coated ePTFE surface in a serum-supplemented medium, are shown to be not only morphologically, but functionally differentiated, and will provide us a model system for the development of a bioreactor using hepatocytes, particularly for a hybrid-type artificial liver.

Dioctophyme renale (Nematoda: Dioctophymatoidea) in the abdominal cavity of Rattus norvegicus in Japan

We collected 24 brown rats, Rattus norvegicus, in Kanagawa Prefecture in Japan and found one rat harboring a dioctophymatid nematode. A single male and a female worm were recovered from the abdominal cavity and were identified as Dioctophyme renale based on morphologic features and a BLAST DNA sequence analysis. We describe the morphological features of the adult worms and eggs from this extremely rare case of D. renale infection in a brown rat.

The occurrence and ape-to-ape transmission of the entodiniomorphid ciliate Troglodytella abrassarti in captive gorillas

Entodiniomorphid ciliates are often present in the colons of wild apes. In captive apes the infection tends to gradually disappear, with the exception of Troglodytella abrassarti. We used fecal examinations to screen the gorillas (Gorilla gorilla gorilla) in European (Czech Republic, UK) and Australian Zoos to explore the ape-to-ape transmission pattern of T. abrassarti. Gorillas from two out of three European Zoos were positive for T. abrassarti, while gorillas from the Australian Zoo were negative. We documented a horizontal transmission of T. abrassarti to a non-infected adult gorilla introduced into a Troglodytella-positive group in the Prague Zoo and traced the origin of the ciliate infection to the Paignton Zoo (UK) using serial fecal examinations. During this study, two infant gorillas born in the Prague Zoo (CZ) first became positive for T. abrassarti at the age of 9 mo. Ciliate morphology and the sequencing of the small subunit rRNA gene and the internal transcribed spacer rDNA spacer region revealed that T. abrassarti affects both captive gorillas and chimpanzees. We conclude that zoo transport plays a major role in the distribution of T. abrassarti among captive gorillas.

(+)-Syringaresinol-di-O-β-d-glucoside, a phenolic compound from Acanthopanax senticosus Harms, suppresses proinflammatory mediators in SW982 human synovial sarcoma cells by inhibiting activating protein-1 and/or nuclear factor-κB activities

(+)-Syringaresinol-di-O-beta-D-glucoside (SR), syringin, and isofraxidin isolated from the stem bark of Acanthopanax senticosus Harms are its major constituents. The present work was undertaken to analyze effects of these compounds on inflammatory functions in SW982 human synovial sarcoma cell system. When cells were exposed to SR, syringin, or isofraxidin, only isofraxidin had significant inhibitory effects on cell growth, although a slight inhibition was observed at the highest concentration of SR. SR suppressed the production of IL-6 at lower concentrations than syringin and isofraxidin. SR and syringin significantly suppressed the production of prostaglandin E(2), while isofraxidin suppressed only slightly. SR was more potent than syringin and isofraxidin at inhibiting the expression of IL-1beta, IL-6, cyclooxygenase (COX)-2 and matrix metalloproteinases (MMP)-1 mRNA, but was less potent than syringin at inhibiting the expression of MMP-2. We further demonstrated that SR significantly reduced MMP-1 promoter luciferase activity and DNA-binding activity of transcriptional factors AP-1 and NF-kappaB. Taken together, these results suggest that SR, an active component of the stem bark of A. senticosus, modulates the inflammatory process involved in arthritis by suppressing various gene expression through inhibiting AP-1 and/or NF-kappaB activities.

Differentiation potential of an immortalized non-tumorigenic human liver epithelial cell line as liver progenitor cells

We report the differentiation potential of an immortalized non-tumorigenic human liver epithelial cell line, THLE-5b. Under basic culture conditions THLE-5b showed undifferentiated phenotypes. When grown as cell aggregates, THLE-5b exhibited a hepatocyte-like ultrastructure, ammonia metabolic activity and several other indicators that suggest hepatocytic maturation, including up-regulation or induction of liver-specific genes such as albumin and tryptophane 2,3-dioxygenase, and down-regulation of biliary cell markers such as gamma-glutamyl transpeptidase (GGT). Under these conditions, transcriptional factors such as HNF-1 and HNF-4alpha were also up-regulated or induced. In Matrigel culture, expression of GGT was up-regulated. THLE-5b expressed both albumin and alpha 1-antitrypsin, but lost expression of CK19 in severe combined immunodeficient mice. Thus, THLE-5b can be aligned with progenitor cells, which are committed to the hepatocytic or biliary epithelial cell lineage. These results imply that bipotent progenitor cell populations similar to THLE-5b cells may exist in adult human liver.

Isolation and cultivation of porcine hepatocytes for extracorporeal artificial liver support system

OBJECTIVE

To develop procedures for the successful harvesting of large quantities of viable and functional pig liver cells from abattoir organs.

METHODS

The procedure included partial liver lobe retrograde perfusion and mechanical/enzymatic digestion of the liver tissue, followed by separation of the hepatocytes, based on size and density, from contaminating cell types.

RESULTS

Digestion of the partial liver lobe resulted in an average yield of 1.39 x 10(9) cells (9.9 x 10(8) cells/g liver) with an average viability of 92.5%. The yield and viability of cells were improved by dispase/collagenase resultant digestion. The emergence of blebby cells was blocked by supplying oxygen to the cell isolation buffers. Isolated hepatocytes seeded onto polystyrene surfaces remained viable and functional at a level comparable to that of rat hepatocytes, although their function decreased over time.

CONCLUSIONS

Adult pig hepatocytes can be harvested with high yields and retain viability and differentiated function using this method. Abattoir pig livers can be an excellent source of hepatocytes for use as the biological component of artificial liver assist devices.

The in vitro differentiating capacity of nonparenchymal epithelial cells derived from adult porcine livers

Specific nonparenchymal epithelial cell (NPEC) clusters derived from normal adult porcine livers demonstrate a characteristic developmental pattern in the presence of other types of nonparenchymal cells in vitro. This pattern includes scattering, colonial growth, and an emergence of duct-like structures (DLSs) in the colonies. It has been confirmed that 96% of the scattered cell clusters in these cultures develop into colonies containing DLSs. In this study, we examine the differentiation of NPEC clusters using the scattered formation as a marker of the DLS-emerged colonies. We report that the NPECs expressed albumin, alpha-fetoprotein, transferrin, cytokeratin (CK) 18, CK7, and c-met, but not alpha-1-antitrypsin (AAT), at the scattering stage. In addition, at the same stage, NPECs expressed oval-cell-related markers such as OV6, but not biliary epithelial cell (BEC) markers such as gamma-glutamyltransferase, CK19, and CK14. At the DLS emerging stage, hepatocyte markers, including AAT, were detectable in the cells either at the periphery of colonies or in the cells surrounded by the DLSs. On the other hand, the cells constituting DLSs expressed BEC markers, suggesting a bile duct nature of the DLSs. Furthermore, the cells in the colonies possessed an ultrastructural appearance of differentiated hepatocytes and BECs. These results suggest that certain NPECs are bipotent, and that, in culture, they mimic hepatoblast development in vivo.

A mild transient decrease of peripheral red blood cell counts induced by a suprapharmacological dose of pegylated human megakaryocyte growth and development factor in rats

Previous studies have shown that pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) at suprapharmacological dose induces a mild transient decrease of red blood cell counts according to thrombopoiesis in normal mice. To unravel the mechanism underlying this mild transient decrease of red blood cells, we have studied the effect of PEG-rHuMGDF on the circulating plasma and blood volume, and the serum biochemical parameters of anaemia and splenectomy. Also, we have performed histological studies of the bone marrow and the spleen of PEG-rHuMGDF-treated rats. PEG-rHuMGDF (300 microg kg(-1)]) or vehicle was subcutaneously administered to rats once a day for up to five days. From day 6 after the start of PEG-rHuMGDF administration, the platelet counts and plateletcrit levels were significantly increased, reaching peak values on day 10, and recovering to normal by day 20. The red blood cell counts and the haematocrit levels were significantly decreased on day 6 to 13. The decreases in red blood cell levels and haematocrit produced by PEG-rHuMGDF treatment were mild and had recovered by day 15. The plasma and blood volumes were significantly increased on day 10 in PEG-rHuMGDF-treated rats. No alteration of the serum biochemical parameters for anaemia, iron or total bilirubin, were observed on day 10. The histological examination on day 10 revealed a marked increase in megakaryocytes and a slight decrease in erythropoiesis in the bone marrow of rats that received PEG-rHuMGDF (300 microg kg(-1)). There was also a slight increase in splenic megakaryocytes and erythropoiesis. The decrease of red blood cells by PEG-rHuMGDF was not affected by splenectomy. These results suggest that the mild transient decrease of red blood cells induced by PEG-rHuMGDF treatment for up to five days is based mainly on the increases in the plasma and blood volume. These events are secondary changes due to the regulation of the excess production of megakaryocytes in the marrow and the peripheral platelets.

Effects of KRN4884 (a novel K+ channel opener), levcromakalim, nilvadipine and propranolol on endothelin-1-induced heart disorders in anesthetized rats

The effects of KRN4884 (5-amino-N-[2-(2-chrolophenyl)ethyl]-N'-cyano-3-pyridinecarboxa midine), a novel K+ channel opener, on the electrocardiogram changes caused by the intracoronary administration of endothelin-1 (ET-1) were studied in anesthetized rats and compared with the effects of levcromakalim, a K+ channel opener; nilvadipine, a Ca2+ antagonist; and propranolol, a beta-adrenoceptor antagonist. KRN4884 (50 microg/kg, i.v.) and levcromakalim (300 microg/kg, i.v.) inhibited the ST segment elevation and the development of arrhythmias induced by ET-1 (5 microg, i.c.) and decreased the incidence of death. Nilvadipine (300 microg/kg, i.v.) and propranolol (1000 and 3000 microg/kg, i.v.) each prevented the ST segment elevation, but the suppressions of the occurrence of arrhythmias produced by nilvadipine and propranolol were less than that shown by KRN4884. KRN4884 (30 and 50 microg/kg, i.v.), levcromakalim (100 and 300 microg/kg, i.v.) and nilvadipine (100 and 300 microg/kg, i.v.) significantly decreased the mean blood pressure in a dose-dependent manner, but propranolol did not. The heart rate was decreased by nilvadipine (100 and 300 microg/kg, i.v.) and propranolol (1000 and 3000 microg/kg, i.v.), but was not affected by KRN4884 (30 and 50 microg/kg, i.v.) or levcromakalim (100 and 300 microg/kg, i.v.). These results suggest that pretreatments with KRN4884 and levcromakalim are more effective on ET-1-induced electrocardiogram changes than those with nilvadipine and propranolol.

Colonial growth and differentiation of epithelial cells derived from abattoir adult porcine livers

The parenchymal cell fraction was isolated from abattoir adult porcine livers and cultured in Dulbecco's Modified Eagles' medium/Ham's F12 medium (DMEM/F12; 1:1) medium supplemented with 5% foetal calf serum, 10 ng/mL glucagon, 10 microg/mL insulin, 60 ng/mL hydrocortisone and eight other factors (NAIR-1 medium). The fraction contained a number of epithelial cells other than hepatocytes, some of which attached to the culture plates as cell clusters and began to grow after 3 days in culture. These epithelial cells growing as colonies were found to express cytokeratin 18 by immunocytochemistry. After 7-8 days, duct-like structures emerged in the central parts of the colonies. The cells constituting the duct-like structures and some cells located outside the structures were positive for cytokeratin 19 and gamma-glutamyltransferase (GGT). The albumin-positive cells were located in the outer parts of the colonies rather than their central parts. Albumin was also detectable in the cells surrounded by the duct-like structures. Moreover, cytochrome P450 IA1 was induced by 3-methylcholanthrene (3-MC) on day 16. These results suggest that porcine liver epithelial cell clusters may contain stem-like cells which can differentiate into mature hepatocytes or bile duct epithelial cells.