Age-related histological changes in the canine substantia nigra

Age-related changes in the canine substantia nigra, were examined using immunostaining for tyrosine hydroxylase (TH), glial fibrillary acidic protein (GFAP), neurofilament (NF), ubiquitin, single stranded DNA (ssDNA), and alpha-synuclein (alphaSN). Brain sections from 34 necropsied dogs, ranging from 2 months to 18 years old, were used for this study. On general histological examinations, several age-related changes, including lipofuscin deposition, polyglucosan bodies, amorphous basophilic inclusions and eosinophilic crystal inclusions, were found in the aged dogs. Immunohistochemically, TH-positive neurons were located only in the substantia nigra. The number of TH-positive neurons was well preserved in all dogs examined, however, the ratio of TH-positive neurons to GFAP-positive glial cells tended to show slight decrease in aged dogs. By ssDNA immunostaining for apoptotic cells, there were no significant results in the number of ssDNA-positive neurons. The number of ubiquitin- and NF-positive swollen neurites was increased markedly in aged dogs. Ubiquitin immunostaining revealed a small number of basophilic and eosinophilic inclusions, although both types of inclusions were negative for NF. By alphaSN immunostaining, no neurons were immunoreactive and no basophilic or eosinophilic intracytoplasmic inclusions were revealed. These results indicate that in the substantia nigra of aged dogs the dopaminergic neurons are well preserved, but intracytoplasmic inclusions and ubiquitin-positive degenerative neurites are commonly found.     

Proliferative responses to canine thyroglobulin of peripheral blood mononuclear cells from hypothyroid dogs

The immune responses of hypothyroid dogs to canine thyroglobulin (cTg) were evaluated for the proliferative ability of peripheral blood mononuclear cells (PBMC). PBMC from three hypothyroid dogs with high titers of thyroglobulin autoantibody (TgAA) and 3 clinically normal dogs were cultured with 5, 10, or 20 microg/ml of cTg for 72 hr. The proliferative responses of the cells were determined by the level of incorporated BrdU. The numbers of cells expressing Thy-1, CD4, CD8 and IgG in the PBMC were counted by the immunofluorescence method. Proliferative responses to cTg were observed in the cells from hypothyroid dogs. The number of cells expressing IgG and CD8 in the hypothyroid dogs tended to be high compared with the clinically normal dogs. The CD4+ cells in cultures from hypothyroid dogs increased depending upon the amount of cTg. There was a significant (P<0.05) positive correlation between the number of CD4+ cells and the concentration of cTg in the cultures from hypothyroid dogs. These findings suggest a possible relationship between canine hypothyroidism and cellular immunity. Loss of self tolerance to thyroid antigens in CD4+ T cells may play an important role in the development of canine hypothyroidism.     

Biological roles of monoterpene volatiles derived from rough lemon (<Emphasis Type="Italic">Citrus jambhiri</Emphasis> Lush) in citrus defense

Volatile compounds of plants, including monoterpenes, are a possible source of signal molecules that induce defense systems to protect plants from tissue damage. Volatile compounds from rough lemon leaves were trapped by solid-phase microextraction fibers in sealed vials, and subsequent gas chromatography–mass spectrometry and gas chromatography analyses identified the profile of the major components, mainly various monoterpenes. Among several monoterpenes examined, citral, citronellal, and linalool significantly inhibited the spore germination and hyphal growth of Alternaria alternata. The effect of linalool was fungistatic, while the effects of citral and citronellal were partially fungicidal. Wounding of rough lemon leaves induced a significant increase in release of monoterpenes. The release of linalool was the most abundant and was 14.5 times that of unwounded rough lemon leaves. Unlike the wounding treatment, microbe attack did not significantly change monoterpene releases, and there was statistically no difference found in the peak areas from microbe-treated and untreated leaves. Linalool, limonene, and β-pinene also had insect-repellant effects on wild-type Drosophila melanogaster. Expression patterns of defense-related genes in rough lemon and rice significantly changed after treatment with vapors of monoterpene volatiles. Taking these results together, monoterpene volatiles are likely to play roles in the defense of rough lemon against microbe and insect pathogens.     

Cloning of cDNAs encoding multiple subtypes of feline interferon-alpha from the feline epitherial cell line

Mammalian interferon (IFN)-alpha consists of a 23-amino acid signal peptide and a 166-amino acid mature protein. Feline (Fe) IFN-alpha has an extra unique molecule consisting of a 171-amino acid mature protein with a 5-amino acid insertion. We cloned eight new subtypes of cDNA encoding FeIFN- alpha from a feline epithelial cell line. Among all the FeIFN-alpha subtypes, including six that have previously been reported, the variations were found to be far less than those of IFN-alphas of other animals.     

Relationship between retinoic acid receptor alpha gene expression and growth-inhibitory effect of all-trans retinoic acid on canine tumor cells

Retinoids show antitumor effects on human acute promyelocytic leukemia and other tumors via retinoid receptors. In dogs, the role of retinoid receptors in inhibiting tumor development remains unclear. To evaluate the correlation between the degree of expression of retinoic acid receptor alpha (RARalpha) mRNA and the antiproliferative effects of all-trans retinoic acid (ATRA) treatments, expression analysis of RARalpha mRNA and cell growth inhibition assay were performed on 17 established canine tumor cell lines, including 6 mammary gland tumor (MGT) cell lines, 3 osteosarcoma cell lines, 5 melanoma cell lines, and 3 mast cell tumor (MCT) cell lines. Among the cell lines investigated, all 3 MCT cell lines showed high expression of RARalpha, and the most effective cell growth inhibition was observed in ATRA-treated MCT cell lines. However, remarkable antiproliferative effects of ATRA treatments were not observed on other tumor cell lines with moderate or low RARalpha mRNA expression. As a result of the relationship between RARalpha mRNA expression and ATRA treatment with regression analysis, statistically significant correlation was suggested. Furthermore, real-time quantitative polymerase chain reaction analysis of RARalpha was performed on MCT tissue samples of dogs with spontaneous disease, and 5 of 9 tissues showed high expression. These results suggest that ATRA may be an effective antitumor agent for MCT in dogs, and that prior measurement of expression of RARalpha mRNA may be a good indicator of the effectiveness of ATRA treatment.     

Effects of the lateral growth rate on wood quality parameters of Eucalyptus grandis from different latitudes in Brazil and Argentina

Climate change resulting from increased atmospheric carbon dioxide (CO₂) and shortages of fossil fuels such as petroleum are major problems worldwide. Under these conditions, demand for woody biomass resources is increasing. We investigated the feasibility of using fast-growing Eucalyptus grandis for material production. Samples of E. grandis were collected from four plantations in different latitude divisions, including tropical and subtropical Brazil and subtropical Argentina. Various xylem qualities were measured and related to the lateral growth rate. Lateral growth rate did not significantly affect the longitudinal released strain of the surface growth stresses or the xylem density at any of the sampling sites. Higher lateral growth rate, higher values of xylem density, and lower absolute values of the released strain were observed in plantations closer to the equator. Higher growth rates in tropical climate promote longer fiber length. In subtropical plantations, smaller diameter trees will produce tension wood with smaller microfibril angles. Planting E. grandis closer to the equator thus produces higher quality wood than in plantations at lower latitudes.     

Specific Oligonucleotide Primers Based on Sequences of the 16S-23S rDNA Spacer Region for the Detection of <Emphasis Type="Italic">Burkholderia gladioli </Emphasis>by PCR

Specific primers were designed based on the sequences of the spacer region between the 16S and 23S ribosomal DNA (rDNA) for direct, rapid and specific detection of Burkholderia gladioli. These primers were named GLA-f and GLA-r. PCR performed on boiled bacterial suspensions yielded an amplification product of approximately 300 bp. No products from other bacterial species, including B. glumae were amplified, even after complete DNA extraction by the cetyltrimethyl-ammonium bromide (CTAB) method. Using the specific primers designed in this study, the PCR method can detect B. gladioli in plant samples within 6 hr. These data demonstrate the potential of specific PCR for the detection of B. gladioli. Received 10 December 2001/ Accepted in revised form 15 April 2002     

Clinical and clinico-pathologic characteristics of Shiba dogs with a deficiency of lysosomal acid beta-galactosidase: a canine model of human GM1 gangliosidosis

The present study was conducted to determine the clinical and clinico-pathologic characteristics of Shiba dogs with GM1 gangliosidosis, which is due to an autosomal recessively inherited deficiency of lysosomal acid beta-galactosidase activity. Clinical and clinico-pathological features were investigated in 10 homozygous Shiba dogs with GM1 gangliosidosis. The age at onset was 5 to 6 months and the dogs manifested progressive neurologic signs including loss of balance, intermittent lameness, ataxia, dysmetria and intention tremor of the head. The dogs were unable to stand by 10 months of age due to a progression of ataxia and spasticity in all limbs. Corneal clouding, a visual defect, generalized muscle rigospasticity, emotional disorder and a tendency to be lethargic were observed at 9 to 12 months. The dogs became lethargic from 13 months of age. The survival period seemed to be 14 to 15 months. As a clinico-pathologic feature, lymphocytes with abnormally large vacuoles were observed in peripheral blood (30 to 50% of total lymphocytes) through the lifetime of the dogs. The clinical and clinico-pathologic characteristics of this animal model are useful for not only the development and testing of potential methods of therapy, but also the diagnosis of affected homozygous Shiba dogs in veterinary clinics.     

Changes in mineral concentrations in amberjack Seriola dumerili larvae during seed production: high concentrations of certain minerals in rotifers do not directly affect the mineral concentrations in larvae

This study examined the changes in mineral concentrations in amberjack Seriola dumerili larvae during seed production taking into consideration the mineral concentrations of rotifers in the larval rearing tanks (tank rotifers), since the concentrations of certain minerals in tank rotifers have been reported to be very high. In the present study, the concentrations of Ca, Mg, Fe, Zn and Mn in tank rotifers were generally higher than in freshly enriched rotifers. The extent of the increase in tank rotifers varied depending on the mineral, larval production facility and larval production trial. Concentrations of Ca in the larvae increased as they grew, those of P and Mn increased up to ca. 30 days post-hatching (DPH), those of Mg and Fe increased up to ca. 20 DPH and then decreased, and those of Zn continuously decreased through the seed production periods (to ca. 40 DPH). However, there were no clear relationships between the mineral concentrations of the tank rotifers and the larvae. These results indicate that high concentrations of minerals in tank rotifers are not directly reflected in amberjack larvae. This suggests that amberjack larvae maintain their mineral status by controlling the uptake and/or excretion of food minerals.     

Plasma concentrations of inhibin A in cattle with follicular cysts: relationships with turnover of follicular waves and plasma levels of gonadotropins and steroid hormones

We investigated the profiles of circulating levels of inhibin A and total inhibin in beef cows with follicular cysts in relation to the patterns of follicular development and circulating gonadotropins and steroid hormones. Turnover of follicular waves was monitored in five cows every 2 days for 70 days from 10 days after detection of estrus without ovulation. The mean interwave intervals were 19.6 ± 1.0 days (n = 18 waves with cysts from the five cows). Circulating levels of inhibin A were approximately 170 pg/ml before emergence of follicular waves with cysts and increased (P < 0.05) concomitantly with follicle emergence. High concentrations of inhibin A (greater than 300 pg/ml) were noted for 7 days during the growth phase of cystic follicles, but inhibin A levels decreased gradually when development of the cysts reached a plateau. This profile of inhibin A was similar to those of total inhibin and estradiol, but was inversely related to the changes in plasma FSH concentrations. LH pulse frequency and mean concentrations of LH in cows with cysts were higher than those observed in the luteal phase of normal cyclic cows. These results indicate that the capacity to secrete inhibin, as well as estradiol, is maintained in cystic follicles, the growth of which is extended by LH secretion at levels greater than those seen in the normal luteal phase. Inhibin A plays an important role in the extension of interwave intervals by suppressing recruitment of a new cohort of follicles.