Cytopathology of chick renal epithelial cells experimentally infected with avian infectious bronchitis virus

The renal ducto-tubular epithelial cells of chicks infected with the MA-87 strain of avian infectious bronchitis virus (IBV) were examined ultrastructurally. Infected epithelial cells containing IBV particles were more numerous in the collecting ducts, collecting tubules, distal convoluted tubules and Henle's loops than in the proximal convoluted tubules. Virus particles invaded host cells through endocytotic vesicles. Cytopathologic changes in the infected epithelial cells were manifested by a variety of organlle alterations including swelling of mitochondria, dilation of Golgi vesicles and an increase in the amount of rough endoplasmic reticulum (RER). Virus particles were produced by budding into RER and, rarely, toward the perinuclear space. As virus replication progressed, virus particles were enclosed mainly in the dilated RER, cytoplasmic vesicles or virus-containing electron-dense bodies. Virus particles were also found in vesicles of Golgi complex, the dilated perinuclear space, in some autophagic vacuoles or free in the cytoplasm. Virus particles were released by exocytosis through cytoplasmic vesicles, or appeared to be discharged through disrupted cell membranes. It was concluded that epithelial cells of lower nephron and ducts are the primary target cells in IBV-infected kidneys.

Histopathology and immunohistochemistry of renal lesions due to avian infectious bronchitis virus in chicks uninoculated and previously inoculated with highly virulent infectious bursal disease virus

A nephropathogenic strain of infectious bronchitis virus (IBV) was inoculated intra-tracheally into 14-day-old specific-pathogen-free chicks or ones previously inoculated with highly virulent infectious bursal disease virus (IBDV) at 7 days of age. The renal lesions were examined histopathologically and immunohistochemi-cally at intervals up to 30 days post-inoculation. The mortality was 20% in the IBDV + IBV-inoculated group, but not in the IBV-inoculated one. Swollen and pale kidneys due to IBV infection were more severe and of longer duration in dually infected chicks. At the early stage of infection, the histopathological changes in the kidneys were similar in both groups, but the ducto-tubular damage was more severe in the dually infected chicks. At the late stage of infection, the renal lesions were characterized by chronic interstitial nephritis with formation of lymphoplasmacytic nodules in IBV-inoculated chicks and by chronic active nephritis which consisted of tubular degeneration, lymphoid cell reaction and interstitial fibrosis in IBDV + IBV-inoculated ones. More IBV antigen-positive cells persisted longer in the kidneys of dually infected chicks than in those of IBV-inoculated ones.

Respiratory and intestinal trichomoniasis in mule ducks

Two types of trichomoniasis, respiratory and intestinal, were found in two duck farms. Based on the morphological features, the organism was identified as Tetra-trichomonas anatis. In the first outbreak, main clinical signs were bilateral swelling of infraorbital sinuses, sneezing and profuse diarrhoea with high fatality (300/400) in young ducks. Histological lesions were confined to the upper respiratory tract and lower small intestine and consisted of mucofibrino-purulent sinusitis and catarrhal rhinitis, tracheitis and enteritis. The protozoa appeared frequently in the infraorbital sinuses, the respiratory region of the nose, and the lower small intestine, but rarely in the trachea. In the second outbreak, the lesions were limited to the lower small intestine with catarrhal enteritis in adult ducks clinically showing profuse diarrhoea and low mortality.

Analysis of transcriptional and translational activities of Marek's disease (MD) virus genes in MD central nervous system lesions in chickens

The expression of Marek's disease virus (MDV) gene products and transcripts was observed in tissues obtained from the central nervous system (CNS) of chickens experimentally infected with a very virulent strain (Md/5) of MDV. Many cells antigen-positive for MDV early gene products, but not for late gene products, were detected immunohistochemically in the necrotizing lymphomatous lesions. The positive signals were found only in necrotic or degenerated neoplastic lymphoblasts. Abundant transcriptional activity of MDV genes was observed in the necrotizing lymphomatous lesions for immediate-early and early genes, but not for late ones, by the reverse-transcription polymerase chain reaction. In the non-necrotizing lymphomatous lesions, as well as non-suppurative ones, there were no or very few antigen-positive lymphoblasts for early and late genes, and little transcriptional activity of MDV genes. The necrotizing lesions of the lymphoma were associated with necrotizing vasculitis in which endothelial cells exhibited up-regulation of MHC class II antigen but no viral antigens. The present results indicate that only necrotizing lymphomatous lesions revealed abundant incomplete cytolytic cycle in MDV latently infected neoplastic lymphoblasts.

Histopathology and immunohistochemistry of renal lesions due to infectious bronchitis virus in chicks

Two-day-old specific-pathogen-free chicks were inoculated intranasally with the MA-87 strain of infectious bronchitis virus, and trachea and kidney lesions studied histologically and immunohistochemically. Lesions and viral antigen were first detected in the trachea; severe damage was then observed in the kidney. Viral antigen appeared prior to the development of renal lesions and was detected in the cytoplasm of epithelial cells by 4 days post-inoculation (p.i.). The epithelial cells of the collecting ducts, collecting tubules and distal convoluted tubules were first affected, followed by involvement of Henle's loops, whereas the proximal convoluted tubules were only minimally affected. Antigen-positive cells of ducts and tubules were degenerated and desquamated. The severe epithelial cell damage resulted in infiltration of heterophils and macrophages in the interstitium, ducts and tubules. The detection of viral antigen was consistent with the distribution of histological lesions at 6 to 8 days p.i. At a later stage, antigen-positive cells disappeared and repair of epithelial cells was seen, accompanied by interstitial lymphoplasmacytic infiltration and lymphoid nodular formation.

Hypoalgesic behaviors of P/Q-type voltage-gated Ca2+ channel mutant mouse, rolling mouse Nagoya

Rolling mouse Nagoya (tg(rol)) is a spontaneously occurring P/Q-type voltage-gated Ca2+ channel (VGCC) mutant mouse. A P/Q-type VGCC with the tg(rol) mutation has lower voltage sensitivity of activation, and mice with a homozygous genotype (tg(rol)/tg(rol)) but not with a heterozygous genotype (tg(rol)/+) show impaired motor coordination of the hind limbs. To investigate the roles of P/Q-type VGCC in pain sensing mechanisms, behavioral responses of adult tg(rol) mice to thermal, mechanical and chemical nociceptive stimuli were examined by the plantar, tail-flick, von Frey and formalin tests. The latency of the withdrawal response to thermal stimuli in the plantar or tail-flick tests was significantly longer in tg(rol)/tg(rol) mice than in tg(rol)/+ and wild-type (+/+) mice, and in tg(rol)/+ mice than in +/+ mice. The withdrawal response to mechanical stimuli in the von Frey test was lower in tg(rol)/tg(rol) mice than in +/+ mice. Although the licking time during the first 5 min after the formalin injection was similar among all of the three genotypes, that during 5-60 min was significantly shorter in tg(rol)/tg(rol) mice than in tg(rol)/+ and +/+ mice, and in tg(rol)/+ mice than in +/+ mice. Artificial inflammation induced by injection of complete Freund's adjuvant (CFA) into a hind paw significantly enhanced the withdrawal response recorded in the plantar and von Frey tests regardless of the mouse genotype. The CFA-enhanced response in the tg(rol)/tg(rol) mice was similar to the response in +/+ mice without the CFA injection. These results suggest that tg(rol) mutant mice show hypoalgesic responses caused by a lower sensitivity to nociceptive thermal, mechanical and chemical stimuli. It is concluded that the P/Q-type VGCC has a pro-nociceptive role and that the tg(rol) mutant mouse may be a useful tool to investigate the role of the P/Q-type VGCC in pain sensing mechanisms.

Brain lesions in young broiler chickens naturally infected with a mesogenic strain of Newcastle disease virus

Thirty-nine 4- to 5-week-old broiler chickens from an outbreak of Newcastle disease (ND) in Japan were examined pathologically. The causative agent was identified as a mesogenic strain of ND virus. Predominant gross lesions included haemorrhage in the lungs, congestion of the trachea, splenomegaly, atrophy of the thymus and bursa of Fabricius, and whitish discolouration of the brain. Microscopically, there was mild haemorrhagic pneumonia, catarrhal tracheitis, lymphoid necrosis in the spleen, thymus, bursa of Fabricius and caecum and diffuse non-suppurative encephalitis. Lesions associated with encephalitis were characterized by multifocal perivascular cuffing, malacia, demyelination and proliferative vasculitis. Malacic lesions occurred in the hyperstriatum, neostriatum, subleptomeningeal and periventricular regions of the cerebrum, whereas demyelination was seen mainly in the brain stem. The morphological changes that occurred in the brain in these cases were distinctive and the lesions in the lymphoid tissues were related to concurrent infection with infectious bursal disease virus.

Pathology of experimental vitamin D deficiency rickets in growing chickens. II. Parathyroid gland

Histopathological studies were done on the enlarged parathyroid glands in experimental vitamin D deficiency rickets of growing broiler chickens ranging from 1 to 7 weeks of age. Two types of parenchymal cells, light and dark chief cells, were recognised in the control group. The former type of cells appeared predominantly in the stages during which bone growth was the most rapid. The main lesions in the groups deficient in vitamin D were swelling and hyperplasia of the parenchymal cells with increased numbers of mitotic figures, a cord-like arrangement of the cells with the formation of surrounding spaces, and a proliferation of the stromal connective tissue. Swelling and hyperplasia of the parenchymal cells, especially the light chief cells, were regarded as the most characteristic changes in hyperparathyroidism and the cord-like arrangement of cells as the second most characteristic alteration.

Histopathology of monensin-tiamulin myopathy in broiler chicks

Thirty-six 7-day-old broiler chicks were simultaneously given food containing monensin, and water containing tiamulin, both drugs being at normal levels of usage. Equal numbers of chicks on a basal diet and plain water served as the controls. Anorexia, depression, drowsiness, leg weakness and a decrease in body weight appeared on days 2 to 3 of administration in several treated chicks. These clinical signs and growth retardation were prevalent and severe on days 4 to 7, at which time some chicks became recumbent. From day 9, chicks showed gradual recovery from the clinical signs and growth retardation. Histopathologically, the neck and leg skeletal muscles examined were severely affected in treated chicks, but cardiac and pectoral muscles were intact. Besides hyalinisation and floccular change which appeared infrequently in early stage of the experiment, muscle fibres showing an enlargement of the nuclei and a distention of a pale to basophilic sarcoplasm, suggestive of partial myofibrillar lysis and subsequent reparative change, dominated all affected muscles. These degenerative and reparative changes were considered to be distinctive for monensin-tiamulin myopathy in chicks.

Cryptosporidial infection in chickens

Cryptosporidial infection was found in 25 layer and four broiler chickens, aged 40 to 80 days, from 11 flocks on six poultry farms. The infection appeared in 1975 in broiler chickens and in 1976 in layers. On one of the poultry farms the infection occurred over a period of 2.5 years. Tissues most frequently affected with cryptosporidia were the bursa of Fabricius (85%), followed by the respiratory tract (nasal cavity, infraorbital sinus, larynx and trachea) (41%) and caeca (11%). Cryptosporidia in various stages of its life cycle were demonstrated histologically and electron microscopically attached to the host cells, and they were identical to those previously reported in other animals and humans. Hypertrophy and hyperplasia of the lining epithelial cells were noted in both the bursa of Fabricius and the respiratory tract. The histological alterations in the respiratory tract, especially the trachea, were sufficient to consider cryptosporidia as a primary cause of respiratory disease.

Aspergillosis and candidiasis in psittacine and passeriforme birds with particular reference to nasal lesions

High incidences of aspergillosis (12.9%) and candidiasis (15.4%) were encountered in 241 psittacines and passeriformes which died within 2 weeks of quarantine after being imported into Japan. Respiratory aspergillosis was diagnosed in 31 birds which involved mainly the nasal cavity (17 birds), lung (14 birds) and air sac (13 birds). Thirty-seven birds had candidial lesions in various organs, especially in the nasal cavity (22 birds), crop (17 birds), oesophagus (12 birds), proventriculus (6 birds) and gizzard (6 birds). The study provided strong evidence that the nasal cavity was an important entry and multiplication site for the both mycoses in psittacine birds. Aspergillus spp. had an affinity for the respiratory region of the nose, inducing an exudative rhinitis. Two types of tissue reaction, invasive and granulomatous, were found in the lung and air sac, although the former type was predominant. Candida spp. often attacked the vestibular region of the nose. This agent caused a hyperkeratotic change in the nasal cavity and other mucous membranes such as the crop, gizzard and cloaca. Cutaneous aspergillosis and candidiasis with or without poxvirus infection were also observed.

Distribution of rabbit haemorrhagic disease virus RNA in experimentally infected rabbits

Adult rabbits were inoculated with liver homogenate from a rabbit that died in a Japanese outbreak of rabbit haemorrhagic disease (RHD). All experimentally infected rabbits died with typical clinical, gross and histological findings of RHD. Distribution of RHD virus in tissues of the infected rabbits was studied by non-isotopic in-situ hybridization. Both viral plus- and minus-strand RNAs were detected within the cytoplasm of hepatocytes, Kupffer cells and splenic and alveolar macrophages, mainly in morphologically intact cells. Strand-specific reverse transcriptase-polymerase chain reaction also demonstrated viral minus-strand RNA as well as plus-strand RNA in the liver, lung and spleen of infected rabbits. These results suggest that viral replication occurs not only in hepatocytes but also in macrophages. The infected macrophages may contribute to viral dissemination in RHD.

Extrahepatic bile duct malformation causing intrahepatic cholangiocellular proliferation with fibrosis in broiler chickens

Malformation of the extrahepatic biliary tracts was observed in six of 88 enlarged, firm and discoloured livers collected at a slaughterhouse. Histologically, the six livers were characterized by diffuse cholangiocellular proliferation with fibrosis, extremely similar to the condition induced by bile duct ligation. These findings suggested that some cases of cholangiohepatitis in chickens are caused by biliary malformations with bile stasis.

Ganglion cysts in a juvenile dog

Ganglion cysts were diagnosed in a 4-month-old male Afghan Hound. Grossly, the subcutaneous ovoid cysts around the caudal right elbow joint and left ischiatic tuberosity had abundant mucinous fluid and internal folding. The lesions recurred twice around the elbow joint after surgical removal. Neither cyst communicated with the joint cavity. Histologically, the cyst wall consisted of inner myxomatous and outer immature connective tissue. Some parts of the cyst wall had various stages of myxoid metaplasia of collagen tissue leading to new cyst formation. Ultrastructural study revealed that cells in the myxoid metaplastic lesion had well-developed cytoplasmic secretory elements, including abundant rough endoplasmic reticulum, Golgi apparatus, and many smooth-walled vesicles. These ganglion cysts apparently resulted from the metaplasia of fibroblasts to secreting cells.

Lead poisoning in wild waterfowl in Japan

We collected 430 harvested ducks (Anas sp. and Aythya sp.) from nine prefectures in Japan between 1994 and 1997. Fifteen (4%) of 363 birds harvested during and after hunting seasons had one lead pellet each in the proventriculus and gizzard. In addition, 32 (34%) of 93 swans (Cygnus sp.) and two of 14 geese (Anser sp.) found dead from various wetlands had lesions consistent with lead poisoning. One to nine swans suspected of having toxicosis from ingestion of lead shot were found dead each year. Twenty-seven (84%) of the 32 lead-exposured swans were found in Hokkaido Prefecture. We concluded that lead poisoning is still a serious threat to waterfowl in Japan and that there is considerable need for environmental improvement concerning this problem.

Distal axonopathy does not occur without neurofilament accumulation in gamma-diketone neuropathy: comparative studies of normal and neurofilament-deficient quail

The neurotoxic effects caused by chronic exposure to 2,5-hexanedione (2,5-HD) were investigated in normal and neurofilament (NF)-deficient quail (Quv strain). These quail were given 175 mg/kg per day of 2,5-HD intraperitoneally for 24 weeks. Five of nine normal quail showed clumsy gait. They had NF-rich axonal swellings in the distal parts of the peripheral nerves, ventral and lateral funiculus of the cervical cord, and cerebellar peduncles. Axonal degeneration consisting of accumulation of mitochondria, vesicles, microtubules and dense bodies was found distal to the axonal swellings. Testicular atrophy appeared in two normal quail. In contrast, four of nine Quv quail showed systemic tonic convulsion, and died of respiratory paralysis within 6 days. No significant changes in the nervous system or testis of these four dead Quv quail. The five other Quv quail survived and did not show any neurological signs. Again, no significant changes were detected in the nervous system or testis of the surviving Quv quail. The present study revealed that distal axonal degeneration did not occur without NF accumulation. These results suggest that NF accumulation is an essential factor in the development of distal axonopathy in gamma-diketone neuropathy.

Hepatic lesions in young rabbits experimentally infected with rabbit haemorrhagic disease virus

Twenty young rabbits (eleven 2-week-old and nine 4-week-old) were experimentally infected with rabbit haemorrhagic disease virus (RHDV) to clarify susceptibility. They were killed chronologically up to 96 hours post-inoculation (PI) and examined for lesions. All inoculated rabbits were clinically normal, but grossly minute white or grey spots were detected throughout the liver. Histologically, the lesions consisted of aggregates of lymphocytes, macrophages and heterophils, with or without acidophilic bodies and necrotic hepatocytes. Immunohistochemically, RHDV antigens were found in the degenerated hepatocytes and in macrophages. The cellular aggregates were considered to be a reaction to necrotic hepatocytes infected with RHDV. It was concluded that some hepatocytes are susceptible to RHDV in young rabbits.

Neurotoxic effects of 2,5-hexanedione on normal and neurofilament-deficient quail

The neurotoxic effects of 2,5-hexanedione (2,5-HD) were investigated using neurofilament (NF)-deficient (Quv) Japanese quail in comparison with normal Japanese quail. Both Quv and normal Japanese quail were inoculated intraperitoneally with 350 mg/kg/day 2,5-HD for 6 consecutive wk. The results of 2,5-HD exposure differed substantially between the 2 strains of Japanese quail. The 2,5-HD-exposed normal quail showed leg paralysis about 4 wk after initiation of dosing. Some treated normal quail fell into dysstasia and died of nutritional disturbances. Histologically, 2,5-HD-treated normal quail had NF-rich axonal swellings and degeneration in the distal parts of the peripheral nerves, spinal cord, and cerebellar peduncles. In contrast, 2,5-HD-injected Quv quail showed tonic convulsion, ataxia gait, severe quivering, and excitation about 2-3 days after administration. Some treated Quv birds died immediately after systemic tonic convulsion, probably because of asphyxia. Although all treated Quv quail showed neurologic signs, there were no recognizable 2,5-HD-induced lesions in the nervous system. After about 4-6 wk of dosing, 2,5-HD induced distal axonopathy in normal quail and acute neurotoxicity in Quv quail.

Cytology of feather pulp lesions from Marek's disease (MD) virus-infected chickens and its application for diagnosis and prediction of MD

Cytological changes of feather pulp lesions (FPL) sampled chronologically from the same specific-pathogen free chickens inoculated with Marek's disease virus serotype 1 (MDV) were examined, comparing with their histological changes. The birds having Marek's disease (MD) lymphomas or nerve lesions exhibited the characteristic lesion changes on the cytological smears of FPL; the initial non-suppurative inflammatory to the late lymphomatous FPL. The birds having neither the MD visceral lymphomas nor the nerve lesions manifested only non-suppurative inflammatory FPL on the cytological smears throughout the experimental periods. Histological evaluation of FPL sampled from the same birds confirmed as above mentioned cytological results. From these results, the cytological evaluation of FPL proved to be an effective diagnostic and prognostic tool in foreseeing MD incidence.

Bronchiolar-alveolar carcinoma in a cow

Bronchiolar-alveolar carcinoma was observed in the lung of an 8-year-old Holstein cow. Grossly, the lung contained multiple tumour masses, which were solid, yellowish-white in colour, and firm in consistency. These tumours also occurred in the liver, pancreas, uterus and lymph nodes in the thoracic, abdominal and pelvic cavities. Histologically, the masses were composed of abundant fibrous stroma and proliferating atypical cuboidal epithelial cells, occasionally forming glandular structures. Electron microscopy revealed that the neoplastic cells had microvilli and lamellar bodies in the cytoplasm, suggesting that they originated from immature respiratory epithelial cells differentiating towards either Clara cells or type II pneumocytes.

Hantavirus infection in SCID mice

Severe combined immunodeficiency (SCID) mice were inoculated with Hantaan virus strain 76-118 (HTN) or Seoul virus strain SR-11 (SR) of hantaviruses. Susceptibility of SCID mice was compared with those of immunocompetent adult mice, newborn mice and nude mice. SCID mice inoculated with HTN or SR died 32 to 35 days after infection. Unlike newborn mice which also died of hantavirus infection, SCID mice survived longer than newborn mice and showed typical wasting symptoms rather than nervous symptoms. Immunohistochemical staining and virus isolation indicated that both HTN and SR inoculated SCID and SR inoculated nude mice showed systemic infection, but nude mice inoculated with SR survived for longer than 8 weeks after inoculation. Passive transfer of spleen cells from immunocompetent BALB/c mice conferred protection on SCID mice within 2 weeks of HTN infection. Immune mediated pathologic mechanism was examined by transferring the spleen cells to SCID mice inoculated with HTN virus 3 weeks before the cell transfer. The recipient SCID mice showed an increase of serum BUN level coinciding with the appearance of serum antibody to HTN virus, suggesting the immune mediated pathogenicity.

Fibrin(ogen)-related antigens in rabbits experimentally infected with rabbit haemorrhagic disease virus

We investigated fibrin(ogen)-related antigens in liver tissues of rabbits infected with rabbit haemorrhagic disease (RHD) virus. Fibrin(ogen)-related antigens were detected in the sinusoids of liver at six hours post infection (pi). At 18 hours pi, the antigens were clearly detected in the hepatocytes infiltrated with heterophils rather than in the sinusoid. In the rabbits that spontaneously died (30 hours pi), fibrin(ogen)-related antigens were detected in both degenerating and some intact hepatocytes. They were also expressed in the necrotic foci of hepatocytes infiltrated by heterophils. By immunoprecipitation fibrin(ogen)-related antigens were extracted from the infected liver homogenates and analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis and Western blot analysis. There was an increase in fibrinogen and A alpha polypeptide chains in the liver homogenates from rabbits sacrificed at 18 and 24 hours pi, including those that died. Disseminated intravascular coagulation developed after progress of degeneration and necrosis of hepatocytes in RHD. It is assumed that the resultant consumption of fibrinogen triggers replenishment of fibrinogen by hepatocytes.

Apocrine gland tumor of the eyelid in a dog

A 13-year-old male Shetland Sheepdog with progressive exophthalmos had a neoplastic mass in the ocular adnexa. Histologically, this neoplasm was composed of duct-forming epithelial cells with decapitation secretion. Tumor cells invaded the globe through the tunica conjunctiva and replaced the vitreous body. The cornea, iris, ciliary body, and retina were extensively destroyed. Both the epithelial and spindle-shaped myoepithelial cells showed nuclear atypia and mitotic activity in the globe. The primary tumor was diagnosed as adenocarcinoma, probably originating from apocrine sweat glands of the eyelid, and the infiltrating intraocular neoplasm was diagnosed as a malignant mixed tumor.

Esophageal/gastric adenocarcinoma in a dog

A nine-year-old, intact female, mixed-breed dog was presented with a history of chronic regurgitation and weight loss. Endoscopy and contrast radiography confirmed the presence of a distal esophageal mass. The dog was euthanized, and histopathological diagnosis of the mass was an esophageal/gastric adenocarcinoma.

Age-related changes in the olfactory system of dogs

Age-related changes in the olfactory system were examined in 22 dogs ranging in age from 10 to 19 years old. Atrophic changes with degeneration were observed in the olfactory epithelium of dogs older than 14 years; the changes were prominent in the dogs over the age of 17 years. Immunohistochemistry using an anti-carnosine antibody, which is a marker for the olfactory cells, demonstrated a decrease in the number of olfactory cells. Electron microscopy also showed a decrease in the number of cilia of olfactory cells and microvilli of supporting cells. Atrophic changes with the features of regeneration were rarely observed in the aged animals. Lipofuscin-like granules in the olfactory epithelium became prominent with age. These age-related changes were similar to those reported in the olfactory epithelium of man and rats. Dystrophic neurites were not detected by a modified Bielschowsky stain or by neurofilament, synaptophysin and tau immunohistochemistry in the olfactory mucosa. There was no beta-amyloid- and ubiquitin-immunostaining in the olfactory mucosa. Senile brain changes, including cerebrovascular amyloidosis, age-related astrocytic gliosis and ubiquitin deposits were found in the olfactory bulb, although neurofibrillary tangles and senile plaques were not detected either by a modified Bielschowsky stain or by beta-amyloid immunohistochemistry. These results indicate that dog may be a useful animal model to study the age-related changes in the olfactory system in man.

Regeneration of myelinated fiber after crush injury is retarded in sciatic nerves of mutant Japanese quails deficient in neurofilaments

Regeneration of myelinated fibers in the sciatic nerve 2 weeks after crush injury was studied morphometrically in mutant Japanese quails deficient in neurofilaments and in normal quails (controls). There were fewer regenerated myelinated fibers per nerve at 10 mm (R1) and 20 mm (R2) distal to the crush site in mutants than in controls (P < 0.05). Both median and maximum diameters were smaller (P < 0.01) in mutants than in controls. On electron microscopy, transverse axonal area and axonal circumference were smaller (P < 0.001) at both R1 and R2 in mutants than in controls. The number of myelin lamellae was less (P < 0.01) in mutants than in controls at R1, but was similar at R2. There were fewer myelin lamellae in relation to axonal area in mutants than in controls at R1 (P < 0.0001) and R2 (P = 0.0032). The results indicate a retardation of both radial growth of axons and myelination around axons of the same size in mutants compared with controls. Such retardation may be explained by the deficiency of neurofilaments and the altered relationship between Schwann cell and axon in the mutant.

Inherited muscular disorder in mutant Japanese quail (Coturnix coturnix japonica): an immunohistochemical study

Cryostat sections of myofibres from the Musculus pectoralis thoracicus of a newly established mutant strain (LWC) of Japanese quail with a myotonic dystrophy-like myopathy were labelled with antibody against myosin heavy chain (MHC) isoforms and neural cell adhesion molecule (N-CAM). The characteristic lesions found in sections of muscle of LWC quail stained with haematoxylin and eosin were type 2B fibre atrophy, sarcoplasmic masses, and ring fibres. Immunohistochemical examination failed to distinguish type 2A and 2B fibres in the LWC quail. Antibody to adult fast MHC, which reacted only with type 2A fibres in normal quail, reacted in LWC quail with type 2B fibres, and to a limited degree with type 2A fibres. Sarcoplasmic masses reacted with both fast and slow MHC antibodies. Some masses also reacted with NCAM antibody, but apparently independently of similar reactions in fibres. These findings suggest that the changes observed in the myofibres of the LWC quail were not neurogenic but represented defects in both the plasma membrane and intermediate filaments.

Inherited muscular disorder in mutant Japanese quail (Coturnix coturnix japonica): an ultrastructural study

Ultrastructural study of muscles taken from a mutant (LWC) strain of Japanese quail with myotonia showed type 2 fibre atrophy, ring fibre formation, sarcoplasmic masses, and "moth-eaten" fibres. In these abnormal fibres, the most characteristic feature was the loss of interconnection among the myofibrils, mitochondria, and T tubules. Apparently normal muscle fibres often showed mild changes, such as proliferation of T tubules and enlarged sarcoplasmic areas with increased glycogen granules and ribosomes at the periphery of the fibres. The study suggested that one possible cause of these ultrastructural changes was a defect in cytoskeleton of muscle cells, especially in intermediate filaments.

Life span and tumours in the first-generation offspring of the gamma-irradiated male mouse

C57BL/6 male mice were exposed to 3 Gy 60Co gamma-rays and mated with unirradiated females after 15 days to produce F1 progeny produced following irradiation of the spermatids. After weaning the offsprings were allowed to live their normal life span. The mean litter size of the irradiated group significantly decreased from 7.1 to 4.9 (p < 0.01), but the sex ratio was not altered by the irradiation. No significant differences in the survival curve and mean life-span between the irradiated and control groups were noted. The only radiation effect in tumour incidence was a decrease of histiocytic sarcoma in female offspring of irradiated males. Except for this, there were no significant differences between the irradiated group and the control group in the incidence or age distribution of tumours.

Peripheral neuropathy of dietary riboflavin deficiency in racing pigeons

An occurrence of peripheral neuropathy in nine 14- to 55-day-old racing pigeons was documented. The predominant clinical signs were diarrhea, and leg and wing paralysis. Grossly, there was discoloration and swelling of all the peripheral nerve trunks. Microscopic lesions comprising swelling, fragmentation and demyelination of myelin sheaths, and proliferation of Schwann cells, were seen in the peripheral nerves of all birds examined. These changes were associated with moderate to severe swelling, fragmentation, atrophy and loss of axons. The peripheral nerve lesions in these cases were similar to those of dietary riboflavin deficiency in chickens. An analysis of the diet given to the pigeons indicated that the riboflavin concentration was only 0.9 mg/kg feed.

Fibromuscular dysplasia in intramuscular arteries of Japanese quail (Coturnix coturnix japonica)

Fibromuscular dysplasia (FMD) was found in the intramuscular arteries of both commercial (normal) and mutant (LWC) strains of Japanese quail. The mutant strain LWC is afflicted with an inherited muscular dystrophy exhibiting myotonia. The arterial lesions were classified as medial fibroplasia or medial hyperplasia, both being subtypes of medial FMD. Some lesions showed extensive proliferation of medial smooth muscle into the vascular lumen, resulting in partial occlusion of the affected blood vessel. FMD occurred more frequently in the mutant LWC quail than in the commercial strain. Ischaemic changes were absent in the associated muscle structures in both strains. The significance of FMD in relation to the skeletal muscle changes in the mutant LWC strain remains unclear.

Changes of GTP binding proteins, not neurofilament-associated proteins, in the brain of the neurofilament-deficient quail, "Quiver"

A neurofilament (NF)-deficient mutant of the Japanese quail was named "Quiver", as it showed generalized quivering as a clinical sign. NF consists of three major subunits; low, middle and high. We previously reported that the noradrenaline and 5-hydroxytryptamine content in the neostriatum of the Quiver's brain was different from that in the normal quail, although disappearance of the three NF proteins occurred in all areas of the Quiver's brain. Thus, NF-related proteins may show considerable changes in the specific sites of Quiver's brain. In this study, an examination was made of the changes in NF-related proteins in the Quiver, by immunoblotting analysis. The amounts of cyclin-dependent kinase 5 (cdk5), which phosphorylates NF proteins, and tau which is a substrate of cdk5, in the neostriatum of the Quiver, were essentially the same as those in the normal quail, although NF proteins could not be detected in the Quiver. The amount of alpha-tubulin in the Quiver's brain was similar to that in the normal quail. Next, we investigated the changes of GTP binding (G) proteins in the Quiver's brain, because cytoskeletal components such as tubulin and F-actin bind with G proteins. [32P]ADP-ribosylation of G proteins (Gs by cholera toxin and Gi/G0 by pertussis toxin) in the neostriatum of the Quiver increased significantly, although alpha subunits of G proteins showed no change by immunoblotting analysis. The ratios of the trimer form in G proteins thus appear to increase more in the NF-deficient Quiver brain than in the brain of the normal quail. The G proteins-mediated adenylate cyclase activities were the same in the brain of both the Quiver and the normal quail. Possible interactions between NFs and G proteins are discussed.

Neuropathological studies of chickens infected with highly pathogenic avian influenza viruses

Central nervous system lesions of chickens inoculated with three highly pathogenic avian influenza virus strains, A/chicken/Victoria/1/85 (H7N7), A/turkey/England/50-92/91 (H5N1), and A/tern/South Africa/61 (H5N3), were examined histologically and immunohistochemically. The chickens either died within 7 days of inoculation or were killed 2 weeks after inoculation. No significant differences were observed in the lesions induced by these three viruses. The lesions were divided into two types, disseminated foci of microgliosis and necrosis, and ventriculitis. The former lesions were associated with infection of the vascular endothelium and dissemination of the virus to the peripheral parenchymal cells of the chickens that died within 3 days of inoculation. The ventriculitis lesions, however, were observed mainly in the chickens that died between 4 and 7 days after inoculation. These findings suggest that viral infection of the vascular endothelium and subsequent involvement of ependymal cells play important roles in the pathogenesis of the central nervous system lesions.