A case of spontaneous Zymbal’s gland carcinoma with lung metastasis in an aged Fischer 344 rat

Zymbal’s gland neoplasms are induced in rats through the administration of various carcinogens, but spontaneous neoplasia is rare. This report describes a spontaneous Zymbal’s gland carcinoma with lung metastasis found in an aged male Fischer 344 rat. Macroscopically, the dome-like tumor nodule, approximately 30 mm in diameter with ulceration, was located near the ear canal of the rat. No healthy tissue or structure of Zymbal’s gland was identified on the corresponding side, while the normal salivary glands and a lacrimal gland were observed. Histologically, a large part of the tumor mass was occupied by poorly differentiated neoplastic cells, the shapes of which were oval to polygonal or fusiform. Additionally, clusters of sebaceous-like foamy cells and squamous metaplasia with prominent keratinization were observed. Tumor cells were found to metastasize to the lung; these cells displayed histological similarities, including a sebaceous gland-like pattern, to those in the primary site. The tumor cells were immunohistochemically positive for cytokeratin AE1/AE3 or vimentin but negative for CD68, S100, α-smooth muscle actin, von Willebrand factor, and desmin. Our results indicate that the tumor was a poorly differentiated Zymbal’s gland carcinoma with lung metastasis.     

Experimental transplacental transmission of canine herpesvirus in pregnant bitches during the second trimester of gestation

The effects of canine herpesvirus (CHV) on fetuses were studied after IV inoculation of pregnant bitches in the 2nd trimester of gestation. Cesarean sections were performed on 2 bitches that were inoculated with CHV on the estimated 30th day of gestation. Bitch M-1 had 2 mummified fetuses and bitch M-2 had 4 mummified and 2 dead fetuses and 3 live-born pups. Infection by CHV was confirmed histopathologically by the presence of focal areas of necrosis associated with intranuclear inclusion bodies in heart muscle sections of 1 dead fetus; CHV was not recovered from other organs. Abortion occurred between the 2nd and 3rd week after inoculation of another pregnant bitch inoculated with CHV on the estimated 30th day of gestation. Two bitches inoculated with CHV on the estimated 40th day of gestation gave birth prematurely to 10 pups. The detection of characteristic herpesviral lesions in various organs and the reisolation of CHV from the liver, spleen, kidneys, and lungs of premature pups indicated CHV infection. Transplacental infection of fetal pups by CHV resulted in their death and subsequent mummification. It appears that abortion and premature birth also may occur in pregnant bitches infected during the 2nd trimester of gestation.     

Characterization of new monoclonal antibodies against porcine lymphocytes: molecular characterization of clone 7G3, an antibody reactive with the constant region of the T-cell receptor delta-chains

A battery of mouse monoclonal antibodies (mAbs) reactive with porcine peripheral blood (PB) leukocytes was generated. Among the mAbs, 6F10 was found to react probably with cluster of differentiation (CD)8 alpha-chain, while 7G3 and 3E12 were found to recognize gammadelta T-cells, as revealed by two-color flow cytometric and immunoprecipitation studies. 7G3 was shown to react with the constant (C) region of the T-cell receptor (TCR) delta-chain by the following facts: (1) 7G3 immunoprecipitated full-length TCR delta-chain protein fused with glutathione S-transferase (GST) produced by Esherichia coli and (2) 7G3 reacted with TCR delta-chain expressing Cos-7 cells transfected with either full-length or N-terminal deleted mutant cDNA, but did not react with Cos-7 cells transfected with C-terminal deleted mutant TCR delta-chain cDNA. All three mAbs produced high-quality immunostaining results on frozen sections, revealing a distinct distribution of gammadelta T-cells and CD8(+) cells. This report precisely characterizes mAbs against porcine TCR for the first time, facilitating molecular biological investigations of the porcine immune system.     

Increased Cellular Distribution of Vimentin and Ret in the Cingulum of Rat Offspring After Developmental Exposure to Decabromodiphenyl Ether or 1,2,5,6,9,10-Hexabromocyclododecane

Abstract: To determine effects of developmental exposure to brominated flame retardants (BFRs), weak thyroid hormone disruptors, on white matter development, white matter-specific global gene expression analysis was performed using microdissection techniques and microarrays in male rats exposed maternally to decabromodiphenyl ether (DBDE), one of the representative BFRs, at 10, 100 or 1000 ppm. Based on previous gene expression profiles of developmental hypothyroidism and DBDE-exposed cases, vimentin⁺ immature astrocytes and ret proto-oncogene (Ret)⁺ oligodendrocytes were immunohistochemically examined after developmental exposure to representative BFRs, i.e., DBDE, 1,2,5,6,9,10-hexabromocyclododecane (HBCD; 100, 1000 or 10,000 ppm) and tetrabromobisphenol A (TBBPA; 100, 1000 or 10,000 ppm). Vimentin⁺ and Ret⁺ cell populations increased at ≥ 100 ppm and ≥ 10 ppm DBDE, respectively. Vimentin⁺ and Ret⁺ cells increased at ≥ 1000 ppm HBCD, with no effect of TBBPA. The highest dose of DBDE and HBCD revealed subtle fluctuations in serum thyroid-related hormone concentrations. Thus, DBDE and HBCD may exert direct effects on glial cell development at ≥ middle doses. At high doses, hypothyroidism may additionally be an inducing mechanism, although its contribution is rather minor.     

Unilateral intrauterine horn insemination of frozen semen in cats

Frozen feline semen was prepared using two types of extenders, egg yolk Tris-fructose citric acid (EYT-FC) and egg yolk sodium citrate solution (EYC), and the semen qualities after thawing and the conception rates obtained by unilateral intrauterine horn insemination (UIUI) were investigated. Cats used in the experiment were six males and 11 females aged 2-12 years (the number of experimental cases was 17). For preparation of frozen semen, semen collected by the artificial vagina method was adjusted to I x 10(8) sperm/m/ and 7% glycerol, put in 250 microl straws, and then frozen using a cell freezer. The mean sperm motility after thawing was 30.0+/-9.7 (SE) % in the semen prepared with EYT-FC and 30.0+/-3.3% in the semen prepared with EYC. Four of seven animals were fertilized by UIUI using two straws in both extenders, and the conception rate was 57.1%. The mean ratios of number of kits to the number of ovulations in the inseminated side were 61.1+/-24.5% and 30.5+/-3.4% for EYT-FC and EYC, respectively, showing that the ratio tended to be higher in the semen prepared with EYT-FC. The above findings, comparing the two extenders for preparation of frozen feline semen, showed that EYT-FC is slightly superior to EYC. To increase conception and fertility rates, it may be important to increase the sperm count for insemination and to inseminate both uterine horns.     

Detection of DNA of 'Candidatus Mycoplasma haemominutum' and Spiroplasma sp. in unfed ticks collected from vegetation in Japan

DNA fragments of 'Candidatus Mycoplasma haemominutum', a feline heamobartonella pathogen, were detected from unfed Ixodes ovatus collected from vegetation in Hokkaido, Fukushima and Yamaguchi Prefectures, and unfed Haemaphysalis flava in Yamaguchi Prefecture. This finding suggests that ixodid tick is a possible vector of 'C. Mycoplasma haemominutum'. Spiroplasma DNA was also detected from unfed I. ovatus in Hokkaido, Fukushima and Yamaguchi Prefectures. The analysis of nucleotides sequence suggested that this Spiroplasma was distinct from registered species.     

Characterization of ammonia-assimilating bacteria in a lagoon for wastewater from a paddock of dairy cattle

We investigated microorganisms that assimilated ammonia in lagoon treatment processes. Ammonia‐assimilating microorganisms were detected by nitrogen‐limited medium that contained ammonia as the sole nitrogen source. Numbers of ammonia‐assimilating aerobes (log CFU/g) were 3.4, 4.8, 5.0, 4.8 and 5.0 (log CFU/mL) on the culture plate incubated at 4°C, 10°C, 15°C, 20°C and 25°C, respectively. Many isolates used ammonia in high rates when they were purely cultivated in nitrogen‐limited medium added to sterilized lagoon extract. Many of them used ammonia even when they were cultivated in media containing viable microbial flora of the lagoon. Among them, enterobacteriaceae and Pseudomonas sp. were identified by analysis of 16S ribosomal DNA.     

Transcellular penetration of Treponema phagedenis isolated from papillomatous digital dermatitis in polarized normal human epidermal keratinocytes in vitro

Papillomatous digital dermatitis (PDD) is a polymicrobial infection causing lameness in dairy cattle. Culture-independent analysis has shown that Treponema phagedenis is present consistently and predominantly in the lesions. However, the pathogenesis of PDD, especially the tissue penetration pathway, has not been examined. In the present study, we investigated whether T. phagedenis strains isolated from PDD produce proteolytic enzyme (s) for disruption of the epithelial cell barrier and have the ability to translocate in polarized normal human epidermal keratinocytes (NHEK) in vitro. Ten strains of T. phagedenis isolated from lesions did not show proteolytic activity on modified skim milk agar, although a human strain of T. denticola used as a control showed such activity. The integrity of tight junctions was monitored by measurement of transepithelial electrical resistance (TER). The TER values after inoculation of the T. phagedenis strains examined did not change during the experimental period; however, apical to basolateral translocation of T. phagedenis was confirmed after 24 hr by microscopy and Treponema-specific PCR. We further confirmed that translocation of T. phagedenis was accelerated by co-inoculation with live T. denticola, but not with heat-killed organisms. Furthermore, tight junction ZO-1 protein was not lost intensity after inoculation with T. phagedenis and the organism was observed in NHEK cells using a florescence microscope. These results suggest that T. phagedenis strains may translocate via a transcellular route in vitro and that the invasion is accelerated by other bacteria, such as T. denticola, producing proteolytic activity.     

Effect of volume of non-surgical embryo transfer medium on ability of porcine embryos to survive to term

Non-surgical embryo transfer is a promising method for improving efficiency in the pork industry and also for biotechnology applications, such as in vitro embryo production, transgenesis and cloning. Several groups have reported successful piglet production using an artificial insemination catheter or flexible catheter designed for this procedure; however, the efficiency of the technique is still low. The critical points that need to be addressed in order to improve this procedure are (1) the embryo deposition site and (2) volume of transfer medium associated with the embryos; however, the latter has not yet been examined systematically. In the present study, we evaluated the effect of the volume of non-surgical embryo transfer medium on the ability of porcine embryos to survive to term by using a recently produced flexible catheter. The catheter consists of a guide and an injector. Blastocysts 200-230 mum in diameter were collected from donor gilts and transferred to recipient gilts. The time required for the completion of embryo transfer using this catheter was 14.6 +/- 3.9 min. The tip of the injector was determined by laparotomy to be located in a uterine horn 20-30 cm anterior from the branching point of the uterus body. We transferred 17.0-17.3 embryos with different volumes of medium (1.6, 3.2 and 10 ml) into each of 5, 4 and 4 recipients, respectively, and pregnancy was confirmed in 4, 3 and 1 of these recipients, respectively. Three recipients in the 1.6 ml group farrowed a total of 19 piglets (4, 5 and 10 piglets, respectively). These results suggest that successful non-surgical embryo transfer is affected by the volume of transfer medium.