The juxtaglomerular apparatus is known to be the functional unit of renin control. In the present review, the author will describe the comparative characteristics of renin-containing (RC) cells as well as extrarenal distribution, paying special attention to developmental and topographical approaches. The characteristic locality of RC cells suggests that the secretion of renin is performed at a site beside the adventitia or via the glomerular capillaries. Ontogenetical and phylogenetical investigations of RC cells have provided interesting findings on their morphogenesis. Analysis of the endocrine kidney after unilateral obstruction of the ureter provides some findings about the origin of RC cells and the processing of renin granules. Observation of developing adrenal renin suggests that there is important involvement of angiotensin II produced by renin synthesis in the morphogenesis of the adrenal gland in the fetal stage. Coagulating gland (CG) renin is characterized by testosterone-regulated and exocrine mechanisms. Recently, all or some of the components of the renin-angiotensin system (RAS) have been reported to be synthesized and secreted outside of classical organs or tissues. In the future, the real function of local RAS will be clarified by using gene targeting in mice.

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Since about 1630, the Imperial Palace has been biologically isolated from other habitats by the development and urbanization of Tokyo. We morphologically examined the skulls of the lesser Japanese mole (Mogera imaizumii) from the Imperial Palace and compared them with those from Kanto District, while the sequences of the cytochrome b and 12S rRNA genes were also analyzed to clarify the genetic status of this isolated population. The skulls from the Imperial Palace were much larger than those from Kanto District in the length items. We suggest that the Imperial Palace skulls morphologically may compose a cluster as a large body-sized type in Kanto District within the dots of Mogera imaizumii in charts of principal component analysis. The mitochondrial DNA sequences of the Imperial Palace population were highly homologous to those of other Tokyo population at the level of 98.5% in cytochrome b and 98.7% in 12S rRNA genes.

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In the murine uterus granulated metrial gland (GMG) cells appear only during normal pregnancy. GMG cells belong to a member of natural killer (NK) cells and play an important role in fetus survival and placental growth. Our previous study revealed that mouse GMG/uterine NK (uNK) cells in the late pregnancy rapidly disappear from the uterus, due to the degenerative change classified as necrosis. But there are few reports regarding appearance and morphology of uNK cells during late pregnancy. We examined histologically and histochemically how and when uNK cells undergo cell death. The uNK cells in the metrial gland increased in number and reached maximum until day 12 of pregnancy. Sudden disappearance, however, occurred after day 15 and the granules reduced in both number and size. In situ DNA fragmentation detection revealed that DNA fragmented uNK cells increased in number during days 13 to 15 and reached 70.2% at day 15 of pregnancy. From days 13 to 17, uNK cells were positive against anti-perforin antibody. Ultrastructurally, uNK cells at day 15 showed poor organelles and unusual granules in structure. In uNK cells at day 17, condensation of nucleus chromatin, reduction in size and phagocytosis into other uNK cells were observed. These results suggested that uNK cells undergo at least two types of cell death, classified as necrosis and apoptosis, at the different stages of pregnancy, and that perforin is not a mediator for cell death.

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The MRI examination was carried out in a formalin-fixed specimen of the Ganges River dolphin (Platanista gangetica), one of the evolutionary primitive species of cetaceans. We could morphologically elucidate the tracheobronchial ramification in the intact whole body. We demonstrated from the MRI sections that the characteristic tracheal bronchus branches from the trachea at the cranial portion. These findings suggest the phylogenetic relationships between cetaceans and artiodactyls. The left bronchus is obviously larger in diameter than the right one. We suggest that the right bronchus has smaller capacity of gas exchange than the left one, because the dolphin possesses the tracheal bronchus in the right lung. The MRI method will be important in the non-invasive study of the anatomy in endangered animal carcass as Ganges River dolphin.

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Thirteen anomalous calves with clefts of the face were morphologically examined, and craniofacial skeletons were studied in detail. According to the type and site of the cleft, four groups could be distinguished: median cleft lip and jaw (CLJ); median cleft lip, jaw, and palate (CLJP); lateral CLJ; and cleft palate (CP), including unilateral and bilateral type. Craniofacial skeletal abnormalities were observed in several bones at the roof, wall, and floor of the nasal cavity and at the boundary portion between the nasal and cranial cavities. Fissure formation at the cranial sutures, partial absence of the nasal process of the incisive bone, and opening of the bony palate were characteristic changes in median CLJ and CLJP, lateral CLJ, and CP, respectively. Furthermore, various associated changes were recognized in the median and paramedian skeletal elements of the face and other organs. The morphological changes of craniofacial skeletons with various types of clefts of the face depended on the site and degree of the cleft formation and reflected developmental errors of the facial embryonic segments. These changes would suggest disorders of the correlated development of facial processes and of other fetal organs of the face. For these conditions, etiologically hereditary cases were negative.

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One of the most attractive characteristics of a horse testis is the change of the weight during development. As the testicular weight changes and the number of Leydig cells decreases, pigments appear in interstitial tissues. In the present study, the characteristics of the pigments found in the interstitial tissues were examined histochemically and ultrastructurally. Specific stainings indicated that the pigmented granules showed almost all of the histological and histochemical characteristics of ceroid or ceroid-like pigment. The cells showed positive reaction for acid phosphatase while the pigmented cells contained a lot of lysosomes ultrastructurally. These results suggest that macrophages might phagocytize Leydig cells, and store their digested materials as ceroid-like pigment.

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An inactivated vaccine prepared from broth culture supernatant of Mycoplasma hyopneumoniae with an aluminum adjuvant was evaluated in three herds (herd A: specific pathogen-free herd, herd B: high health status herd with no clinical signs of respiratory infection, herd C: low health status herd with serious epidemiological and economical problems). A total of 212 pigs from the three herds were divided into two groups. One group was injected twice with the vaccine at 4-week intervals and the other was a control group. No adverse reactions were noted following the vaccinations either systematically or locally in any of the vaccinated pigs from any of the herds. In herd A, the vaccination provided antibody response within 4 weeks after the second vaccination and antibody responses continued for more than 12 weeks. In herds B and C, the number of pigs with lung lesions, mean percentage of lung lesions, and the numbers of M. hyopneumoniae recovered from pigs at slaughter in the vaccinated group were significantly (P<0.05) reduced compared to the control group. Furthermore, vaccination resulted in improved average daily weight gain (ADG), improved feed conversion ratio (FCR), and improved days to market weight in herd C, whereas no difference in growth performance was shown in herd B. It is suggested that the inactivated vaccine prepared from broth culture supernatant of M. hyopneumoniae is effective in reducing clinical signs and lung lesions. Also, vaccination resulted in improved growth performance in herds where clinical signs and economic losses were significant.

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Lecithin:cholesterol acyltransferase (LCAT), the enzyme responsible for esterification of cholesterol in plasma, is reported to be implicated in the regulation of inflammation in laboratory animals. The purpose of the present study was to elucidate the possible relevance of LCAT in the pathogenesis of calf pneumonia induced by inoculations of Pasteurella haemolytica and bovine herpes virus-1 into the calf lung. Serum LCAT activity was significantly (P<0.01) reduced in calves inoculated with Pasteurella haemolytica. The concentration of cholesteryl esters (CE), the product of the LCAT reaction, was also decreased in the inoculated group. Decreases in LCAT activity and the CE concentration were similarly observed in calves in which bovine herpes virus-1 was inoculated. In both bacteria- and virus-inoculated calves, CE concentrations in the high-density lipoprotein fractions were distinctly decreased, whereas those in the low-density lipoprotein fractions were practically unaltered. The acute-phase proteins haptoglobin and serum amyloid A were detected in sera from the bacteria- and virus-inoculated calves; however, the two acute-phase proteins were also found in sera from the control calves. These results suggest that decreases in LCAT activity and the CE concentration are involved in the pathogenesis of pneumonia induced by inoculation of calves with Pasteurella haemolytica and bovine herpes virus-1, and also that the change in the LCAT system is more intimately related to the occurrence of calf pneumonia than the induction of acute-phase proteins such as haptoglobin.

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Elution profiles of total lipoproteins, apolipoprotein B (apoB) concentrations in lipoproteins, and plasma triglyceride (TG) levels were examined in early-, late-, and non-lactating cows. Additionally, arteriovenous (A-V) differences were also measured to elucidate the uptake of TG and apoB-containing lipoproteins in mammary gland. Non-lactating cows showed three major peaks corresponding to triglyceride-rich lipoprotein (TRL), low density lipoprotein (LDL), and high density lipoprotein (HDL) fraction, whereas both early- and late-lactating cows revealed two peaks corresponding to TRL and HDL. The peak area of TRL in early- and late- lactating cows were significantly (p<0.05) smaller than that in non-lactating cows. The plasma TG levels and apoB-48 concentrations of TRL in early- and late-lactating cows were also significantly (p<0.01) lower. Furthermore, early lactating cows showed significantly (p<0.05) larger A-V differences in both plasma TG and apoB-48 concentration of TRL than those in late- and non-lactating cows. These results suggested that TG in exogenous (intestinal) TRL was utilized for milk fat synthesis in lactating mammary gland of cows by the receptor-mediated uptake.

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Telomeres are specific structures present at the end of liner chromosomes. DNA polymerase can not synthesize the end of liner DNA and, as a result, the telomeres become progressively shortened by successive cell divisions. To overcome the end replication problem, telomerase adds new telomeric sequences to the end of chromosomal DNA. The enzyme activity is undetectable in most normal human adult somatic cells, in which shortening of the telomere is thought to limit the somatic-cell life span. In contrast to normal somatic cells, many human tumors possess telomerase activity. The present study looked at whether telomerase activity might serve as a marker for canine tumors. Telomerase activity was measured using the telomeric repeat amplification protocol assay. Normal dog somatic tissues showed little or no telomerase activity, while normal testis exhibited a high level of telomerase activity. We measured telomerase activity in tumor samples from 45 dogs; 21 mammary gland tumors, 16 tumors developed in the skin and oral cavity, 7 vascular tumors and 1 Sertoli cell tumor. Greater than 95% of the tumor samples contained telomerase activity (3∼924 U/2 μg protein). The results obtained in this study indicated that telomerase should be a useful diagnostic marker for a variety of dog tumors, and it may serve as a target for anti-tumor chemotherapy.

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Antibodies to Ehrlichia canis and Hepatozoon canis in dogs at the Animal Hospital in Yamaguchi University were surveyed and potential risk factors for both pathogens were evaluated. Among 430 dogs examined, 20 (4.7%) and 18 (4.2%) dogs showed positive findings for E. canis and H. canis, respectively. Neither, sex nor age was associated with the seropositivity of either pathogen, but the positive rate in dogs kept outside was slightly higher than that in dogs kept inside for both pathogens. A higher seropositive reaction to E. canis and H. canis was observed in dogs that lived in certain cities and towns. Beagles, golden retrievers and pointers had higher seropositivity than other breeds in E. canis, whereas shibas, akitas, beagles, pointers and mongrels had higher positive rates than other breeds in H. canis.

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The concentrations of sodium, potassium, reduced glutathione (GSH) and free amino acids and Na-K-ATPase activity in erythrocytes were examined in 35 purebred Jindo dogs in Korea. The incidence of Jindo dogs with a high potassium concentration and high activity of Na-K-ATPase in erythrocytes (HK phenotype) was 25.7%. The erythrocyte GSH concentration in HK Jindo dogs varied widely, from 2.45 to 12.38 mmol/l of RBCs, and was positively correlated with the erythrocyte glutamate concentration. These results indicate that HK Jindo dogs have normal to very high levels of erythrocyte GSH, which might result from the varying quantity of Na-dependent glutamate influx in the erythrocytes.

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A 1.5-year-old Holstein heifer had a subcutaneous tumor mass (20 cm diameter) on the ventral portion of the neck, and the tumor was diagnosed as a locally invasive myofibroblastoma. It consisted of moderately cellular fibrous tissue, and the interlobular septum of the thymus was invaded by tumor cells. The neoplastic cells were positive for alpha smooth muscle actin and vimentin, but not for desmin. Electron microscopy disclosed the presence of moderately developed rough endoplasmic reticulum and microfilaments with focal densities.

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Borna disease virus (BDV) infection has been suggested to cause spontaneous neurological disease in cats referred to as staggering disease. However the evaluation of BDV infection in neurologically asymptomatic cats remained unclear. In the present study, BDV infected, asymptomatic cats in Tokyo were surveyed both by the presence of plasma antibodies against BDV-p24 and -p40 and by RNA detection in peripheral blood mononuclear cells. Seven of 32 domestic cats (21.9%) were serologically or genetically judged to be BDV-infected. Six cats were positive for anti-BDV antibody and two cats were positive for BDV RNA. Within the 2 RNA-positive cats, only one was positive for anti-BDV antibodies. Furthermore, the findings of anti-BDV-p40 and anti-BDV-p24 antibody-positive cats did not completely overlap. These results suggest that there are neurologically asymptomatic domestic cats infected with BDV present in the Tokyo area.

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The present study was made to know the morphology of the initial invasion and lesions involved in the intestinal colonization of Yersinia enterocolitica serovar O3 in the epithelium of Peyer’s patches of mice. Microfold (M) cells formed a specific structure like a pseudopodium and the bacteria were observed on the surface of the pseudopodium-like structure 4 hr after oral administration of serovar O3. The colonies of serovar O3 were observed in the epithelium and the lamina propria of the Peyer’s patches dome region, and the bacteria grown in the Peyer’s patches were in direct contact with the lumen without covered with the host tissue 24 hr after the administration.

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To understand the mechanisms of uptake of killed bacteria of Yersinia enterocolitica serovar O3 into the epithelium of Peyer’s patches, the killed bacteria were perorally inoculated into mice and observation was carried out by scanning and transmission electron microscopy. Microfold (M) cells formed a specific pseudopodium-like structure and the bacteria were observed on the surface and the interior of the pseudopodium-like structure 8 hr after oral administration of killed bacteria of serovar O3.

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Three 3-month-old Japanese Black calves were experimentally infected with Escherichia coli O157:H7 to define the magnitude (CFU/g) and duration of fecal shedding of the organism. In two of the three calves, fecal shedding of E. coli O157:H7 ceased in 5 and 9 weeks. The remaining calf continued shedding E. coli O157:H7 for more than 31 weeks, and the magnitude of the shedding ranged from 10¹ to 10⁴ CFU/g of feces. The possibility is suggested that a percentage of animals naturally infected with E. coli O157:H7 on farms may become long-term shedders, transmitting the organism to other animals in the herd and to the proximate environment.

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The effects of a cryptorchid testis on the contralateral testis were investigated after artificially producing unilateral cryptorchidism in 8 beagle dogs. Bilateral testicular biopsy and collection of spermatic vein blood and peripheral vein blood were performed at the time of the operation to produce the cryptorchidism and 52 weeks later. The testicular tissue was used for histological examination by light microscopy and measurement of the testicular transferrin (Tf) concentration by enzyme immunoassay. Plasma testosterone (T), estradiol-17β (E₂), and luteinizing hormone (LH) levels were measured by radioimmunoassay. Semen was collected weekly and its quality was examined. No spermatogenesis was observed in the cryptorchid testes at 52 weeks after the operation, and the number of germ cells in the contralateral testes had decreased but the number of Sertoli cells did not change. The Tf concentration in both testes had also decreased. The mean total number of sperm between 48 and 52 weeks after the operation (194 × 10⁶) was less than half the number before the operation (510 × 10⁶). Mean spermatic vein plasma T levels (51 ng/ml) in the cryptorchid testes 52 weeks after the cryptorchid operation were significantly lower than before the operation (91 ng/ml; P<0.05). By contrast, spermatic vein plasma E₂ levels (80 pg/ml) were significantly higher than the values before the operation (51 pg/ml P<0.05). The peripheral plasma LH levels decreased. These findings indicate that a large quantity of E₂ secreted by the cryptorchid testis inhibits the endocrine and spermatogenic functions of the contralateral testis in the dog. In particular, it is assumed that dysfunction of the contralateral testis is associated with Sertoli cell dysfunction suggested by the low Tf concentration.

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A recombinant canine herpesvirus (CHV) which expressed glycoprotein B (gB) of pseudorabies virus (PrV) was constructed. The antigenicity of the PrV gB expressed by the recombinant CHV is similar to that of the native PrV. The expressed PrV gB was shown to be transported to the surface of infected cells as judged by an indirected immunofluorescence test. Antibodies raised in mice immunized with the recombinant CHV neutralized the infectivity of PrV in vitro. It is known that the authentic PrV gB exists as a glycoprotein complex, which consists of gBa, gBb and gBc. In MDCK cells, PrV gB expressed by the recombinant CHV was processed like authentic PrV gB, suggesting that the cleavage mechanism of PrV gB depends on a functional cleavage domain from PrV gB gene and protease from infected cells.

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A wasting disease characterized by progressive weight loss and dyspnea has been observed in weaning pigs on a farm in Yamagata Prefecture in 1998. Histopathologic findings in an affected pig were bronchointerstitial pneumonia and intracytoplasmic clusters of basophilic inclusions in macrophages of lymph nodes, which were similar to those in pigs with postweaning multisystemic wasting syndrome (PMWS) recently reported in North America and Europe. Porcine circovirus (PCV)-like particles were observed in bronchial lymph node of the pig by electron microscopy, and PCV antigens were detected in the lesions by immunohistochemical staining. PCV DNA was also detected in the lung and tonsil by PCR, and restriction fragment length polymorphism analysis of the PCR products with HinfI showed the same type of the PCV associated with PMWS (pmws PCV). Homology of nucleotide sequences between the PCR product and corresponding regions of published pmws PCV genomes was very high. These results indicated that virus detected in this study was pmws PCV. To our knowledge, this is the first report on the presence of pmws PCV in Japan.

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We determined the nucleotide sequence of non-pathogenic Marek’s disease virus serotype 2 (MDV2) strain HPRS24 glycoprotein B (gB) (UL27), ICP18.5 (UL28) and major DNA-binding protein (MDBP) (UL29) genes homologous to herpes simplex virus type 1 (HSV-1). The sequence data revealed that important motives in the proteins are conserved in MDV2 ICP18.5 and MDBP, however the sequence of viral DNA replication origin which exists in the regions between the UL29 and UL30 genes of other alphaherpesviruses was not found in the regions of the MDV2 genome. By northern blot analyses, we also demonstrated that 8.9, 5.0 and 2.6 kb transcripts were actually transcribed from the sequenced region in MDV2-infected cells. The MDV2 UL28 and UL29 genes have not been reported in other serotypes of MDV.

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