Biomedical subjects
Publications and source records attributed to M Mase.
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A method was devised for obtaining dynamic contrast-enhanced T1-weighted and relaxation rate (delta R2*) images simultaneously to evaluate regional hemodynamics of the brain tumors. On a 1.5-T MR system, dual dynamic contrast-enhanced images were obtained using a gradient echo (dual echo fast field echo) pulse sequence with the keyhole technique to improve temporal and spatial resolution during a rapid bolus injection of gadopentetate dimeglumine. The dynamic T1 contrast images were obtained from the first echo: moreover. integral delta R2*dt values were calculated from the first and the second echo images. The dynamic T1 contrast images provided information about characteristic enhancement pattern (vascularization and disruption of blood-brain barrier), and the integral delta R2*dt values provided a map of regional blood pool in tumor site, peritumoral edema, and other surrounding regions of the brain. The ability to obtain dynamic contrast-enhanced T1 contrast and delta R2* imaging at the same time allows optimization of the advantages of each and thereby more information about the microvascular circulation of the brain lesions.
Chicken anaemia virus (CAV) DNA was detectable from various samples such as cell-free virus, infected MDCC-MSB1 cells, unfixed liver homogenates, formalin-fixed liver homogenate or formalin-fixed paraffin-embedded (FFPE) tissues from experimental or field infected chicks using PCR assay. The detection limit of the first PCR assay was 1 infected cell or 10(-1.5) TCID50 of cell-free virus (strain A2). The nested PCR assay increased the sensitivity 10- or 100-fold. CAV DNA was detectable in the other 14 Japanese strains isolated from 1976 to 1994 by the PCR assay. All the amplified products were digested with BglII, HindIII, PstI and SacI. These results suggest that the region amplified was highly conserved among the strains. The nested PCR assay was very sensitive. However, CAV DNA was detectable in most field samples using the first PCR assay. Therefore, the nested PCR assay may not always be necessary. In contrast, the nested PCR assay was necessary to detect CAV DNA in FFPE tissues or formalin-fixed material. Use of the PCR assay in CAV DNA detection from FFPE tissues may be most valuable in diagnosis of diseases caused by or associated with CAV, because it allows detection of both microscopic lesions and CAV DNA.
In order to determine whether the current field strains of egg drop syndrome (EDS) 1976 viruses adapt to chickens, we compared the growth efficiency of three Japanese field strains (PA-1/79, AWI/98, Gifu/01) in chicken and duck embryo liver cells. The growth efficiency in chicken or duck embryo liver cells was almost similar in these strains. The fiber protein may carry the type-specific antigen and the hemagglutination activity, and hexon protein may contain the subgroup-specific antigenic determinants. Therefore, the fiber head and hexon loop 1 DNA domain sequences of the six Japanese field strains UPA-1/79, ME/80, 44/81, Kyoto/91, AWI/98, Gifu/01) were compared, but these DNA domains were identical among the six field strains. Our data suggested that the EDS virus was maintained without discernible changes for the last two decades in the field.
A micro-indirect immunofluorescent antibody (micro-IFA) test with a 96-well, flat-bottomed microplate was developed for measuring avian pneumovirus (APV) antibodies. Two Japanese APV strains (MM-1, 8597/CV94) isolated at different places and times and Vero cells were used for antigen preparation in this test. The test results were compared with those of a serum neutralization (SN) test. By the micro-IFA test, specific immunofluorescent antigens were observed in the cytoplasm of cells infected with either strain, and the antibody titers of antisera to these strains were quite similar. In most cases, the results were obtained within 3 hr. Antibody titers between the micro-IFA and SN tests were highly correlated, with correlation coefficients of 0.873 (MM-1 strain) and 0.889 (8597/CV94 strain). We also investigated APV antibody status in two farms for a period of about 2 yr by the micro-IFA test and revealed that APV infections were repeated within these farms. On the basis of these results, we conclude that our micro-IFA test is useful for routine serologic surveys of APV infections, particularly when a large number of samples are to be treated, because this test was time and labor saving relative to SN tests or conventional IFA tests utilizing embryo tracheal organs or coverslip cell cultures.
The mortality and pathology caused by serotype 4 adenovirus, isolated from chickens with hydropericardium syndrome (HPS) in Japan, was investigated in specific-pathogen-free (SPF) chickens. One-day-old to 15-mo-old SPF chickens were inoculated intramuscularly, orally, and intranasally with liver homogenates from HPS chickens or isolated serotype 4 adenovirus. There were no clinical signs before death. The mortality rate in all groups of 1-day-old chicks was 100%, irrespective of the inoculum or inoculation route. Four-week-old chickens inoculated with liver homogenate also had a 100% mortality rate. Five-week-old chickens inoculated with cell culture of HPS adenovirus had a 40% mortality rate. The mortality rates of 7-mo-old hens inoculated with liver homogenates intramuscularly and orally were 75% and 25%, respectively. In 15-mo-old hens inoculated with liver homogenates intramuscularly, the mortality rate was 70%. Gross lesions were hydropericardium and swelling and congestion of the liver with occasional petechial hemorrhages. Histologically, the liver had diffuse or multifocal hepatic necrosis and hemorrhage with intranuclear inclusion bodies noted within hepatocytes. In the spleen, macrophages containing erythrocytes and yellow pigment were prominent in the red pulp. In the lung, a moderate diffuse macrophage infiltration was noted throughout the lung parenchyma, and these macrophages contained yellow pigment. In the pancreas of the chicks inoculated at 1 day old, there was multifocal necrosis of glands with intranuclear inclusion bodies. Intranuclear inclusion bodies were seen also in the gizzard, proventriculus, duodenum, cecum, kidney, and lung of the chicks inoculated at 1 day old. Immunohistochemically, the intranuclear inclusion bodies of various organs showed positive reactions against group I avian adenovirus. Adenovirus was recovered from the liver of chickens with HPS. This study indicates that HPS adenovirus is able to reproduce HPS lesions and mortality in SPF chicks and even adult chickens and that it is a highly pathogenic strain.
The pathogenicities of inclusion body hepatitis (IBH) and hydropericardium syndrome (HPS) strains of adenovirus for specific-pathogen-free (SPF) chicks were compared. One-day-old SPF chicks inoculated intramuscularly with the DPI-2 (serotype 2), S-PL1 (serotype 2), TR630 (serotype 8), and Saga97 (serotype 8) strains from IBH and with the LVP-1 strain (serotype 4) from HPS exhibited the mortality, liver enlargement, and hydropericardium characteristic of gross change found in HPS. The chicks inoculated with the IBH and HPS strains exhibited similar histologic and immunohistochemical changes. Neither mortality nor pathologic changes occurred in 3-wk-old SPF chicks inoculated with IBH strains, although HPS strain induced HPS lesions in them. This study indicates that IBH strains of adenovirus can also reproduce HPS lesions and mortality in 1-day-old SPF chicks and that IBH and HPS strains may have similar pathogenicities except for their different virulence for older chickens.
Two outbreaks of gizzard erosion in slaughtered broiler chickens in Japan were examined pathologically and microbiologically. The prevalences of such lesions were 9%-11% and 4%-50% in the affected flocks. Affected chickens had no clinical signs. Group I fowl adenovirus (FAV) serotype 1 was isolated from gizzard lesions. Histologically, gizzard mucosa were necrotic. Intranuclear inclusion bodies were seen in the enlarged nuclei of degenerating epithelial cells of the gizzard. The keratinoid layer in the erosion was edematous and desquamated and contained degenerative cells. Moderate to marked inflammatory cell infiltration was observed in the lamina propria and perivascular connective tissue in the submucosa and muscle layer. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies within degenerating epithelial cells. Ultrastructurally, numerous viral particles were demonstrated in the inclusions.
In this paper, we report spontaneous gizzard nematodiasis in an adult Japanese mountain hawk eagle (Spizaetus nipalensis). Grossly, the gizzard had a black mucoid substance attached to the surface mucous membrane, and the heart was dilated. Histologically, immature larvae with yellow pigments invaded crypts of the mucous membrane. More developed larvae invaded the lamina propria and muscular layers and serosa of the gizzard, with pressure atrophy and cellular reaction (infiltration of heterophils and macrophages and proliferation of fibrous connective tissue). Moderate bronchopneumonia due to larvae invasion was also seen in the lung. The morphology suggests that the parasites may be nematodes, but the species of nematode could not be confirmed. The bird may have died from malabsorption and respiratory damage as a result of the gizzard and lung lesions.
Marked proliferation of macrophages engulfing yellow pigments and fragmented erythrocytes were seen in the air capillaries and blood capillaries of the lungs of chickens affected with acute fatal viral hydropericardium syndrome, highly pathogenic infectious bursal disease, and highly pathogenic avian influenza. Proliferation of lung macrophages was associated with systemic proliferation of macrophages. Acute destruction of erythrocytes in these infections may have induced systemic hyperplasia of macrophages. The acute and severe proliferation of lung macrophages may cause acute respiratory dysfunction and be one of the factors inducing mortality in infected chickens. This syndrome may be categorized as "virus-associated hemophagocytic syndrome."
Since 1990, highly virulent infectious bursal disease virus (IBDV), which induces high mortality, has been infecting even vaccinated flocks in Japan. We report the efficacy of three live vaccines that are available in Japan. Two mildly attenuated strains (A and B) and one intermediate strain (C) were each tested both in specific-pathogen-free (SPF) chickens and in commercial chickens that have maternal antibodies against IBDV. Chickens were vaccinated at 20 days old and challenged with highly virulent IBDV 10 days post-vaccination. Protection was determined 7 days after challenge by measuring bursa/body weight ratios, histopathological lesions, and antibody responses to IBDV. All three lie vaccines conferred protection to SPF chickens. However, only vaccine C protected 100% of vaccinated commercial chickens against highly virulent IBDV; Vaccines A and B respectively protected three-fourths and none of vaccinated commercial chickens from severe bursal lesions. Vaccines A, B, and C and highly virulent IBDV induced bursal lesions in 3%, 0%, 23%, and 61% of inoculated commercial chickens, respectively. These results suggest that serological determination of the optimum vaccination time for each flock is required to effectively control highly virulent IBDV in the field. The optimum vaccination timing could be approximated by titrating the maternal IBDV antibodies of 1-day-old chicks by an enzyme-linked immunosorbent assay or by an agar gel precipitin test.
In order to develop an infectivity assay for infectious bursal disease virus (IBDV), an enzyme-linked immunosorbent assay (ELISA) for detecting IBDV antigens was developed using a rabbit antiserum to IBDV. The ELISA detected both serotypes 1 and 2 of IBDV, purified virus proteins at a concentration of about 0.1 ng/well and about 10(4) to 10(5) infectious units/well, and was about 10(3) times more sensitive than an agar gel precipitin test. By using the ELISA for detecting IBDV antigens in the cultured fluids, infectivity titration could be determined within 5 days of cultivation in seven of the 10 virus-cell combinations when chicken embryo fibroblasts (CEFs), BGM-70 cells, and LSCC-BK3 cells were used. IBDV antigens were not detected in three combinations remaining after 7 days of cultivation. When 18 IBDV strains, including highly virulent, classically virulent, and attenuated strains, were tested for growth in four types of cells using the ELISA, eight strains in CEFs, seven strains in chicken kidney cells, five strains in BGM-70 cells, and 17 strains in LSCC-BK3 cells were detected. These results indicated that LSCC-BK3 cells had the broadest spectrum for IBDV. When 26 field bursal homogenates were tested for infectious IBDV using LSCC-BK3 cells, all 19 field IBDV isolates that were detected by immunostaining of the cells were also detected by the ELISA. These results indicate that this infectivity assay for IBDV using LSCC-BK3 cells and the ELISA has a high sensitivity and a broad spectrum for IBDV and is especially useful for large-scale applications.
In order to study replication efficiency of infectious bursal disease virus (IBDV) in lymphoid tissues, both the virus titers and the virus antigen titers in four lymphoid tissues were compared among chickens inoculated with Ehime/91 (about 50% mortality), J1 (no mortality), or K (attenuated) IBDV strains during 1-7 days postinoculation (PI). IBDV antigens in tissue homogenates were detected by an enzyme-linked immunosorbent assay. In the bursa of Fabricius, higher virus titers were maintained for 1-3 days PI in chickens inoculated with Ehime/91 or J1 strains, whereas the virus titers increased gradually and reached to the peak on 3 days PI in chickens inoculated with the K strain. There were no clear differences in both the virus and the virus antigen titers in bursae and thymus between chickens inoculated with Ehime/91 and J1 stains. However, the virus and/or the virus antigen titers in spleen and bone marrow of chickens inoculated with Ehime/91 strain were higher than those of the J1-inoculated chickens. Immunohistochemical analyses indicated that larger numbers of IBDV antigen-positive cells were detected in spleen and bone marrow of the Ehime/91 group than in those of the J1 group. There was almost no detectable virus and virus antigens in thymus, spleen, and bone marrow of the K-inoculated chickens throughout the experiment. These results suggest that efficient replication of IBDV not only in the bursa but also in the spleen and the bone marrow may be required for clinical infectious bursal disease.
Ten 250-day-old broiler breeders, seven 16-day-old broiler chicks, and three 25-day-old broiler chicks suffering from hydropericardium syndrome (HPS) in Japan were examined histologically, immunohistochemically, and ultrastructurally. Clinically, the chickens died suddenly without apparent signs. The mortality rates were 6.4%, 20.2%, and 26.1%, respectively. The common characteristic histologic lesion was necrosis of hepatocytes, accompanied by intranuclear inclusions of hepatocytes and hemorrhages. In the spleen, there were activation of macrophages in splenic sinus and ellipsoids and erythrophagocytosis in the splenic sinus. The interlobular interstitium of the lung showed marked edema. The air and blood capillary areas of parabronchi included many macrophages with yellow pigments. With immunoperoxidase staining, intranuclear inclusion bodies within degenerating hepatocytes stained positively for group I adenovirus antigen. Ultrastructurally, numerous viral particles (65-70 nm in diameter) were demonstrated in the intranuclear inclusions of hepatocytes. Group I adenovirus (serotype 4) was isolated from liver samples of adult broiler breeders and broiler chicks with HPS. This study suggests that HPS may be caused by group I adenovirus.