Kosaku Fujiwara

Molecular Identification of Candida Parapsilosis from Crop Mucosa in a Cockatiel

A 2-month-old cockatiel was evaluated for diarrhea, dyspnea, and death. Histologic examination of lesions in the crop mucosa revealed hyperkeratosis and the presence of blastoconidia and hyphae. Positive immunohistochemical staining of the organisms was achieved with an antibody directed against Candida spp. Polymerase chain reaction amplification of DNA from crop lesion material with internal transcribed spacer 2 (ITS2) primers yielded fragments of approximately 300 bp, which demonstrated 95% DNA homology with the corresponding sequence from a strain of Candida parapsilosis deposited in the GenBank data base. The Candida species in the lesion of the crop mucosa was therefore identified by DNA sequence analysis as C. parapsilosis.

The route of transmission of hemagglutinating encephalomyelitis virus (HEV) 67N strain in 4-week-old rats.

Four-week-old Wistar rats were inoculated with HEV by different routes. Animals died of encephalitis after intraperitoneal (i.p.), subcutaneous (s.c.) and intravenous (i.v.) as well as intracerebral (i.c.) and intranasal (i.n.) inoculation. However when inoculated subcutaneously, rats died a few days earlier than those inoculated i.p. and i.v., suggesting that the virus might be transmitted to the central nervous system (CNS) by the neuronal route rather than by blood stream. Rats which were inoculated subcutaneously at the site of the neck (group A) began to die on day 4 p.i., a few days earlier than animals inoculated in the foot pad of the right leg (group B). On day 2 and 3 after inoculation, the virus titer in the brain was higher in group A, but group B animals showed higher virus titers in the lumber region of spinal cord than group A animals. In order to follow the virus spread from the peripheral nerve to the brain, the virus was inoculated into the sciatic nerve of rats. The inoculated rats developed clinical signs on day 4 and began to die on day 6. On day 2, virus was detected in the posterior half of the spinal cord and migrated toward the anterior half and in the brain where it was present on day 3. The highest virus titers in the brain were recorded on day 4 to 6, meanwhile the virus titers in the spinal cord tend to decrease. By immunohistochemical study, antigen positive neurons were found in the spinal cord and brain on day 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproductive disorders in female rats infected with sialodacryoadenitis virus.

Effects of sialodacryoadenitis virus infection on the reproduction of female SHR rats were studied. The oestrous cycle was considerably perturbed in most infected rats, the perturbation was observed initially between Days 0 to 10 post infection and the effect persisted for 6 to 18 days. About half of the foetuses of dams infected on Day 0 of gestation were found dead while only 4% of the foetuses from non-infected dams were found dead. Five or six days after infection on Day 0 of gestation, some infected dams were shown to have metritis, and virus antigen was detectable within the endometrium as well as exudate cells. In dams infected on Day 5 or later of gestation and severely diseased, the offspring showed a low survival rate possibly because of inadequate nursing.

Characterization of natural killer cytotoxic factor (NKCF) from canine NK cells.

We investigated the presence of canine natural killer cytotoxic factor (NKCF). Canine natural killer (NK) cell-mediated cytotoxicity measured by 51chromium (51Cr) release assay was found to be highest in the T-cell population, which was fractionated into the 35-40% Percoll fraction by discontinuous gradient centrifugation. The cytotoxicity of NKCF in the culture supernatant showed a similar tendency to NK activity. Release of NKCF was rapid after contact with target cells, and reached a plateau in 60 min. The cytotoxicity of NKCF could be detected within at least 15 min in coculture with CL-1 target cells, reaching a plateau in 60 min. We also characterized canine NKCF and found it to be a protein, which was stable against both heat and cold treatment. These findings suggest that canine NK cells release NKCF immediately after recognition and binding to the target cell, and that NKCF plays an important role in canine NK-mediated cytotoxicity.

Acute and late disease induced by murine coronavirus, strain JHM, in a series of recombinant inbred strains between BALB/cHeA and STS/A mice

Abstract To examine the genetic control of acute and late disease induced by a murine coronavirus, strain JHM (JHMV), BALB/cHeA, STS/A, F1 hybrids and 13 recombinant inbred (RI) strains between BALB/cHeA and STS/A mouse strains were inoculated intracerebrally with 100 pfu of JHMV. All the BALB/cHeA mice died within 2 weeks from acute encephalitis. In contrast, STS/A mice were shown to be partially resistant, with a mortality rate of 30%, longer survival times and lower rates of viral production. The mortality rates, survival times and viral titers of F1 hybrids and the RI strains varied, suggesting involvement of multiple genes. STS/A, F1 hybrid and RI mice surviving the acute infection occasionally developed severe paraparesis about 1 month post-infection. In these mice, vacuolar degeneration, astrocytosis, the absence of perivascular cuffing and minimal demyelination were found in the central nervous system. No infectious virus could be recovered from these mice. Although the paralysis of delayed onset was limited to STS/A, F1 hybrid and eight of the 13 RI strains, the incidence varied significantly among the RI strains. These results may suggest that JHMV-induced late disease is also under multifactorial control. The pathogenesis of JHMV infection is discussed.

Immunizing effect of vaccinia virus expressing the nucleoprotein of rinderpest virus on systemic rinderpest virus infection in rabbits

A recombinant vaccinia virus (RVV) expressing the nucleoprotein (NP) of rinderpest virus (RPV) was examined in rabbits for the involvement of the NP protein in protection from the RPV infection. Despite their production of anti-NP antibody, the RVV-immunized rabbits succumbed to the RPV challenge, although there was a slight delay in the onset of disease after the low-dose challenge. On the other hand, the animals immunized with RVV expressing the hemagglutinin (H) protein of the RPV were completely protected. These results indicate that the NP protein might be not so effective as the H protein for the protection against viremic and systemic infection with RPV.

Relationship between radical production and natural killer cytotoxic factor (NKCF) in canine natural killer (NK) cell-mediated cytotoxicity

The relationship between radical production and natural killer cytotoxic factor (NKCF) release via canine natural killer (NK)-mediated cytotoxic mechanism was examined. Radical production and NKCF release was induced in NK cells stimulated with either dead target cells, or their cytoplasmic membranes, as well as live target cells. Canine NKCF evoked target cell lysis but did not induce radical production. Radical production was inhibited by the addition of Tiron or n-propyl gallate, whereas NK-mediated cytotoxicity and NKCF release were only inhibited by the addition of n-propyl gallate. These results suggested that radical production and NKCF release may be induced by the contact and binding of NK cells to the target cell cytoplasmic membrane. Therefore, the release of NKCF from NK cells attached to the target cell cytoplasmic membrane may be associated with the production of radicals, especially hydroxyl radicals.

Lipidosis of the dorsal root ganglia in rats treated with an almitrine metabolite

Toxic effects of a detriazinyl metabolite of almitrine (DTMA) were evaluated in rats and on cultured rat macrophages. In rats daily treated with DTMA for 16 weeks, spastic gaits with heel-lifting appeared, and lamellated and/or crystalloid bodies formed in sensory neurons, satellite cells, Schwann cells, and vascular endothelial cells of the dorsal root ganglia. The lysosomal lamellated bodies, which were not induced by almitrine, were produced also in cultured rat macrophages exposed to over 1 ξ 10−5 M DTMA.

Severe Combined Immunodeficiency (SCID) Mouse Hepatitis Experimentally Induced with Low Virulence Mouse Hepatitis Virus

Severe combined immunodeficient (SCID) mice were experimentally infected with a low virulence strain of mouse hepatitis virus, MHV-2cc, and hepatic lesions of those mice were examined pathologically and compared with those of MHV-2cc hepatitis of athymic nude mice1.

Factors Affecting Infectivity of Tyzzer's Organism in Cultured Mouse Hepatocytes

Factors affecting the infectivity of Tyzzers organism, an obligate intracellular bacterium, were examined in cultured mouse hepatocytes. The organisms were subjected to physical and chemical impairments and the infectivity was estimated by immunofluorescence that discriminated adhesion and entry of the organisms to host cells and by the plaque assay. Pretreatment of the organisms with either mild heat or formalin abolished adhesion. UV irradiation completely removed the plaque forming ability, while adhering and entering capacity were more resistant in this order. Entry of the organism into host cells was suppressed in the presence of erythromycin, gentamicin or oxytetracycline, while it was relatively little susceptible to ampicillin, kanamycin or rifampicin. Plaquing efficiencies were increased by centrifugation during the infection. These results suggest that not only a structural but also a functional integrity of the organisms was requisite for establishment of the infection at the initial stage.