Spontaneous lesions in the common cotton-eared marmosets (Callithrix jacchus), which were maintained in our laboratory or were purchased from a commercial breeder, were examined histopathologically. There were 39 males and 22 females, between the ages of 7 to 100 months. The most interesting finding noted was extramedullary hematopoiesis, which was observed in the mesenteric lymph nodes, spleen, liver, kidney, adrenal gland, and cerebral choroid plexus. Megakaryocytes were frequently observed in the blood vessels of the alveolar wall of the lung. It is important to distinguish extramedullary hematopoiesis which occurs accidentally from that induced by repeated blood sampling or that resulting from administration of chemicals. Extramedullary hematopoiesis was easily distinguishable from inflammation or hematopoietic neoplasms, because of the various cellular elements present, including megakaryocytes. In the weak and dead animals, enterocolitis was found at a high frequency. Other common findings included thymic involution, prominent vacuolation of liver sinusoidal cells, which were probably Ito-cells, and basophilic changes in the renal tubular epithelium. The liver and the kidney are frequently affected by toxic effects of chemicals. Therefore, it is important to distinguish the toxic changes from the spontaneous ones. Proliferation of apocrine glands in the cervical skin was an interesting finding; however, neither inflammatory change nor cellular atypia was noted in this structure. Although its function is unclear, this structure may be a marmoset-specific tissue.

View full abstract

The nucleotide sequences of the spacer regions between the 16S and 23S rRNA genes of six Ureaplasma species were determined following amplification by polymerase chain reaction. The hypothetical secondary structure of the spacer regions was divided into four domains. Domains I and III were highly conserved among different Ureaplasma species but domains II and IV were variable. The intergenic spacer regions of ureaplasmas lacked spacer tRNA genes. Phylogenetic relationships among the Ureaplasma species indicated that the evolutionary history of the Ureaplasma species follows that of the host animal species, suggesting coevolution between ureaplasmas and animals.

View full abstract

A rapid and sensitive method for detecting enterotoxigenic Clostridium perfringens in animal feces and meat is described. The method consists of a combination of nested polymerase chain reaction (PCR) with enrichment culture of the sample. In the PCR, two pairs of oligonucleotide primers homologous to the C.perfringens enterotoxin (CPE) gene were used: the first primer pair amplified a 425-bp fragment and the second one amplified a 199-bp fragment within the fragment amplified by the first PCR. When the specificity and sensitivity of nested PCR in the detection of the CPE gene of isolated C.perfringens were compared with those of the single PCR, the former amplified specifically the 199-bp fragment and the sensitivity was about 10³-fold higher than that of the latter. The nested PCR combined with enrichment culture was applied to detecting the CPE gene in samples inoculated artificially with enterotoxigenic C.perfringens. This method detected within 22-26 hr the CPE gene in samples of animal feces and meat inoculated with fewer than 10¹ CFU/g of enterotoxigenic C.perfringens. When the method was applied to detection of indigenous enterotoxigenic C.perfringens in cattle feces, pig feces, beef and pork, C.perfringens was found in one case (10%) of 10 cattle fecal samples, and the PCR-amplified product corresponded to the fragment of the CPE gene in restriction endonucleases digestion pattern.

View full abstract

To establish an experimental model for vibrionic hepatitis caused by Campylobacter jejuni, Japanese quails (Coturnix coturnix japonica) were inoculated with C.jejuni strains isolated from chicken hepatitis (BL107) and human diarrhea (HP5113). Necrotic liver lesions were formed by intra-pancreaticoduodenal vein injection by which the bacteria reached the liver directly via the portal vein, but not by intra-gastric infection. These liver lesions were observed from day 1 to 7 after the infection. The pathological changes were weak and no clinical signs were observed throughout the experimental period. By immunohistochemistry, the bacterial antigens were detected in the hepatocytes, and intercellular spaces between the hepatocytes, and in the macrophages during the early stage of the infection. When focal hepatocyte necrosis was formed, the antigen was detected more frequently in the intact hepatocytes at the periphery of the lesions than within necrotic foci. The bacteria were not detected from the liver, spleen or blood according to raising the serum agglutination titer. In contrast, the bacteria immediately invaded the bile in 5 min post-infection and were retained in the gallbladder for long periods. The present study showed that necrotizing hepatitis was formed by intra-pancreaticoduodenal vein infection of the quail with C.jejuni.

View full abstract

To investigate the effects of xylazine on pregnant goats, xylazine induced changes in heart rate (HR), arterial blood pressure (ABP) and arterial blood pH and gases in the mother and fetus, as well as changes in intrauterine pressure (IUP) and uterine blood flow (UBF), were studied using a chronic preparation model of pregnant goats. Intramuscular administration of xylazine (0.2 mg/kg b.w.) caused a marked decrease in HR and ABP of the mother, which remained significantly reduced up to 120 min. In the fetus, a significant decrease in HR and a significant increase in ABP were recorded after only 5 min. Significant decreases of maternal arterial blood pH and oxygen partial pressure (Po₂) were observed up to 120 and 30 min after the injection, respectively. Fetal arterial blood pH and Po₂ also decreased, but these changes were milder and less persistent than those of the mother. Within 2 to 5 min after the administration of xylazine, IUP began to increase and remained high for about 15 min. Thereafter, there was a frequent periodic increase in IUP. After 5 min, UBF decreased significantly and remained low up to 120 min. A fall in UBF was associated with a rise in IUP. These findings suggested that administration of xylazine to pregnant goats results in a decrease in UBF arising from the induction of uterine contractions, a decrease in circulating blood volume, hypoxemia and acidosis in the mother.

View full abstract

Polyclonal anti-canine interleukin-8 (cIL-8) antibodies were raised in rabbits immunized with cIL-8 expressed by E.coli. Polyclonal antibodies were purified by affinity chromatography. In the enzyme linked immunosorbent assay (ELISA), the resulting anti-cIL-8 antibodies showed relatively high reactivities with cIL-8 in the fusion proteins of glutathione-S-transferase/cIL-8 (GST/cIL-8) and maltose binding protein/cIL-8 (MBP/cIL-8), but negligible ones with MBP. Furthermore, Western blotting analysis using these polyclonal antibodies showed distinct bands for cIL-8, GST/cIL-8, and MBP/cIL-8. These antibodies also bound to recombinant human IL-8 (rhIL-8) in ELISA but not in Western immunoblotting. The rhIL-8 (50-800 ng/ml) was chemoattractant for canine neutrophils in a dose dependent manner, but the anti-cIL-8 antibodies did not show the inhibitory effect on the chemotactic activity of rhIL-8 for canine neutrophils, when tested by the chemotaxis assay using Boyden chambers. In addition, GST/cIL-8 and rhIL-8 induced strong and rapid shape change responses of canine neutrophils. However, the anti-cIL-8 antibodies inhibited shape change responses induced by GST/cIL-8 but not by rhIL-8.

View full abstract

The seasonal occurrence of Rhipicephalus sanguineus on dogs was examined at a kennel in Okayama Prefecture, Japan. The number of ticks suddenly decreased after treatment with an acaricide in late August. Small numbers of adults and nymphs were detected in September and October, then ticks were not seen on the dogs early in November, when the mean temperature was below 15°C. Then 3 dogs were found to be infested by some adult ticks toward the end of March, when the mean temperature was above 11°C. The effects of temperature on the oviposition and the development of the tick were examined under laboratory conditions. The larval and nymphal post parasitic period, the pre-oviposition period and the oviposition period were prolonged when the temperature was decreased from 37 to 23°C. The oviposition period was extremely long at 14°C, but the tick could not develop below 14°C. No eggs hatched below 14°C. The ability to attach and engorge of adult ticks was examined under cold conditions. Unengorged adult ticks could attach to rabbits on the ear which were kept in an outdoor kennel in October, November and March, however they could not engorge completely in November. They could not attach on rabbits from December to February. The longevity of the tick was also examined under low temperatures. Unengorged adults could attach and engorge on rabbits after kept at 12°C with 50% relative humidity (RH) for 140 days or 12°C with 50% RH for 40 days followed by 4°C with 50% RH for 100 days. These findings suggest that R.sanguineus could be established in Okayama Prefecture under optimum condition.

View full abstract

Cytoarchitectural study indicated that the dorsal motor nucleus of the vagal nerve (nX) was formed by two subnuclei in a coronal section. One of them had large and round neurons, and occupied the dorsal part of the nX (Xd). The second one had small and oval neurons, and occupied the ventral part of the nX (Xv). The double labeling fluorescent method was performed to determine the organization of preganglionic neurons in the nX innervating different muscles of the quail stomach. Injections of nuclear yellow (NY) into the proventriculus, and of fast blue (FB) into the gizzard showed that there were no double-labeled neurons in the nX. NY- and FB-labeled neurons were found throughout the nX. After separate injections of NY and FB into both the cranioventral and caudodorsal thick muscles, and the craniodorsal and caudodorsal thin muscles, many NY- and FB-labeled neurons were distributed and intermingled in the middle two thirds of the nX. Considerable numbers of double-labeled neurons were also found at the middle level of the nX. There was no side-predominancy of the population of the preganglionic neurons innervating the quail stomach. These results show that, many neurons of both sides of the nX are separately innervating both the proventriculus and gizzard, and considerable numbers of single neurons of the nX also innervate a pair of thin or thick muscles with collateral axons.

View full abstract

Mechanical responses to noradrenaline (NA) were recorded in longitudinal muscle strips from the terminal and intermediate regions (3-10 cm and 30-40 cm from the ileo-caecal junction, respectively) of the guinea-pig ileum. NA (0.16-1, 600μM) produced a concentration-dependent contraction in the terminal ileum with the EC₅₀ value of 11.9±4.3μM (n=5). In the intermediate ileum, NA produced relaxation at concentrations ranging from 0.016μM to 1.6μM. Responses to NA at 16μM varied among preparations: no noticeable change in tension, a moderate relaxation and a small contraction. At higher concentrations, NA produced contractile responses and their peak tension increased in a concentration-dependent manner. The contractile effect of NA in the terminal ileum remained unaltered after treatment with propranolol (1.4μM) or yohimbine (1.1μM), or a combination of these drugs. In the intermediate ileum, the relaxant effect of NA was markedly reduced or abolished by propranolol (1.4μM). Yohimbine (1.1μM) had little effect on NA-induced relaxation. The contractile effect of NA in both the terminal ileum and intermediate ileum was inhibited by prazosin (1.1μM), so that the contractions were converted to relaxation or markedly reduced. Propranolol abolished the relaxant responses induced by NA at 0.16μM, but did not inhibit those induced by NA at 1.6μM. Methoxamine (0.16-1, 600μM) produced a concentration-dependent contraction in both the terminal ileum and the intermediate ileum. The EC₅₀ was 93.5±28.5μM (n=8) in the terminal ileum and 83.3±27.7μM (n=10) in the intermediate ileum. There was no significant difference between the values. The results showed that NA is capable of producing contraction or relaxation in the longitudinal muscle layer of the terminal and intermediate regions of the guinea-pig ileum. The contraction, which is mediated by α1-adrenoceptors, predominates in the terminal ileum, but relaxation, which is mediated by β-adrenoceptors and uncharacterized adrenoceptors, predominates in the intermediate ileum.

View full abstract

Sympathetic postganglionic and sensory neurons were labeled by injecting a mixed solution of horseradish peroxidase and wheat germ agglutinin conjugated horseradish peroxidase into the splenic portion or the duodenal portion of the cat pancreas. Labeled postganglionic neurons (about 25, 000 cells) were located bilaterally in the celiac and cranial mesenteric ganglia (91%), mainly in celiac ganglia, and in the paravertebral ganglia T5 to L7 (9%), especially in T13 to L2. Labeled sensory neurons (about 2, 70O cells) were found bilaterally in the dorsal root ganglia T3 to L5, chiefly in T10 to L1. Some differences were found in the localization of labeled postganglionic and sensory neurons between the two portions of the pancreas. Injection into the splenic portion revealed more labeled neurons in ganglia on the left side, while injection into the duodenal portion gave rise to a greater number of labeled neurons on the right side. Paravertebral and dorsal root ganglion cells innervating the splenic portion were concentrated in fewer ganglia than those supplying the duodenal portion. Compared to the splenic portion, the duodenal portion tended to be innervated by more cranially located neurons in paravertebral and dorsal root ganglia. These neurons provably control the secretion of the endocrine and exocrine pancreas, but the differences in the localization of the labeled neurons between the two portions may be related to the different intraabdominal positions of the two portions of the pancreas.

View full abstract

Color flow mapping areas of mitral regurgitation jets (MRMA) and aortic forward flow mapping area (AFMA) were measured in 33 dogs for quantitative evaluation of pathological changes of mitral insufficiency, according to NYHA criteria, by the color Doppler method. The ratio of these areas (MRMA/AFMA) was calculated and the result showed a high correlation (r=0.95) with the result of NYHA evaluation. The result of the present study, which corresponded to the NYHA findings, showed that the color Doppler method can be used for quantitative assessment of mitral insufficiency in dogs.

View full abstract

The effects of two immunostimulators, active egg white product (AEWP) and dihydroheptaprenol (DHP), on involution of lymphoid organs were investigated in mice exposed to heat and cold stress. Heat (37°C, 45 min) and cold (4°C, 4-24 hr for 4 days) stress induced involution of the thymus and/or spleen. AEWP was administered orally at a dose of 500 mg/kg for 4 consecutive days after exposure to heat stress or during cold stress. DHP was injected intramuscularly at a dose of 100 mg/kg on the 4th day after exposure to heat or cold stress. In mice exposed to heat and cold, the ratio of thymus to body weight was significantly higher in the AEWP- and DHP-treated groups as compared to the non-treated group (P<0.01), also the ratio of spleen to body weight was significantly higher in the DHP-treated group as compared to the non-treated group (P<0.01). These results showed that AEWP and DHP markedly alleviated involution of the thymus and/or spleen due to heat and cold stress.

View full abstract

Oxidative damage to canine erythrocytes infected with Babesia gibsoni was investigated. B.gibsoni was cultured together with erythrocytes from normal dogs. When parasitemia reached a peak level, concentrations of both methemoglobin (metHb) and malondialdehyde (MDA), an end product of lipid peroxidation, in erythrocytes were significantly higher than at cultivation Day 0. In addition, B.gibsoni-infected dogs with high parasitemia showed significant increases of both metHb and MDA concentrations in erythrocytes compared to those in uninfected dogs. Furthermore, erythrocytes from parasitized culture were more susceptible to phagocytosis by bone marrow macrophages from normal dogs than erythrocytes from the control culture. In addition, macrophages ingested not only parasitized erythrocytes but also non-parasitized cells. These results suggested that oxidative damage to erythrocytes was induced by the multiplication of B.gibsoni, and that non-parasitized erythrocytes were also exposed to oxidative stress during the infection by B.gibsoni.

View full abstract

Severe cytopathic effects, formation of swollen cells and small syncitia, appeared in 19-PFT-F cell cultures at 2 days when a large amount of the OFl strain of porcine cytomegalovirus (PCMV) was inoculated and cultured in media containing 5, 10, 30 and 60 ng per ml of 12-Ο-tetradecanoylphorbol 13-acetate (TPA). Characteristic focal clusters of swollen cells appeared on the 19-PFT-F monolayers 3 to 4 days after inoculation with a small amount of the virus. Cells in the foci contained specific fluorescent antigens in the nucleus and cytoplasm. The infectivity could be determined for 4 days after inoculation by means of measuring focus formation in the presence of medium containing TPA. The virus replicated more rapidly in the medium with, rather than without, TPA.

View full abstract

Changes in the serum protein patterns accompanying inflammation in young broilers were examined by polyacrylamide gradient gel electrophoresis. Sera were obtained from blood of 4-week-old male broilers after induction of acute inflammation by an injection of 0.5 ml/kg turpentine. Electrophoretic patterns at 48 hr after injection, showed an increase in transferrin (Tf) and a segment containing albumin (Alb) with multiple peaks. The unbound iron binding capacity (UIBC) increased by 10 times, and the serum iron (SI) concentration in acute inflammation was reduced to one-half its initial value. These are considered to be typical changes in serum proteins and iron after acute inflammation.

View full abstract

Outbreaks of a subacute disease characterized by lameness, corneal turbidity, dysstasia and depression occurred in Muscovy ducks (Cairina moschata) on a farm in Aomori Prefecture in February and May 1991. Nine strains of Pasteurella multocida were isolated from 5 of 6 dead ducks, and 4 of 8 ducks with clinical signs. Serotypes of the isolates were identified as Heddleston's serotypes 1, 10 or 12 and Namioka's serotypes 5:A, 8:A, 9:A or 9:UT. These isolates were highly susceptible to 12 antibiotics, although, some of them were considerably resistant to chloramphenicol. Mouse LD₅₀ values of the 9 isolates ranged from 10^1.0 to 10^5.3. The most virulent strain for the mouse killed 2 of 4 ducks when inoculated intramuscularly at a concentration of 10^3.3. This is the first report of outbreaks of fowl cholera in Muscovy ducks infected with various serotypes strains of P.multocida in Japan.

View full abstract

A total of 113 specimens collected from purulent skin lesions of household cats was examined bacteriologically. Ninety seven isolates obtained from 74 specimens (65.5%). Of these, 11 specimens (9.7%) contained obligate anaerobes only, 18 specimens (15.9%) yielded both obligate and facultative anaerobes. In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F.nucleatum was most common species. Pasteurella multocida was the facultative anaerobe which was most frequently detected.

View full abstract

The effect of an anti-progesterone compound, RU-486, administration (20-150 mg) on ovulation in rabbits was investigated. All of the seven control oil-treated rabbits ovulated, whereas, ovulation was blocked in one (12.5%) of eight rabbits treated with 20 mg RU-486, and in 4-6 (66.7-85.7%) of the 6 or 7 rabbits treated with 40-150 mg RU-486. Two successive injections of 10 mg progesterone (P) 4 and 8 hr after RU-486 injection did however recover ovulation in 3 (75.0%) out of 4 rabbits. These results indicate that P secreted from mature follicles during the ovulatory LH surge also play a significant role in follicular rupture of the rabbit, a copulatory ovulator.

View full abstract

The corneal endothelia of 12 female common marmosets (age: 12-18 months) were examined with a contact-type specular microscope under general anesthesia. The specular microscopy showed uniform-sized, hexagonal endothelia arranged regularly on the innermost layer of the cornea. The endothelial plane was smooth; however, it occasionally had irregular undulation or parallel folds. The cell density (cells/mm²) in common marmosets was similar to that in cynomolgus monkeys.

View full abstract

Hepatic nodular fibrosis occurred in an 8-year-old male Papillon dog. Fibrous nodules, consisting of broad bands of collagen fibers, spindle cells, and lipofuscin-laden foamy macrophages, were well-circumscribed and frequently linked up with the portal areas. Because the spindle cells were positive for desmin and/or α-smooth muscle actin, they might be Ito cells or myofibroblasts. These results suggest that both the spindle cells and macrophages play an important role in the pathogenesis of hepatic nodular fibrosis, which might arise from the portal areas.

View full abstract