Seasonal changes in serum total thyroxine, free thyroxine, and canine thyroid-stimulating hormone in clinically healthy beagles in Hokkaido.

The purpose of this study was to evaluate seasonal influences on thyroid hormone levels of healthy outdoor dogs in Hokkaido. We surveyed serum basal total thyroxine (tT4), free thyroxine (fT4), and canine thyroid-stimulating hormone (cTSH) levels, and tT4 levels after administration of TSH for a year. Basal tT4 levels decreased in January, and increased in August and September. fT4 levels increased in January and November. No significant seasonal variation was found in cTSH. tT4 levels after administration of TSH in August and November increased. These results suggested that the thyroid gland may have been activated in November. We should take seasonal variation into consideration when thyroid function is tested.     

Prevalence of tick-borne Rickettsia and Ehrlichia in Ixodes persulcatus and Ixodes ovatus in Tokachi district, Eastern Hokkaido, Japan

DNA from 111 ticks collected by flagging in Tokachi district, Eastern Hokkaido, Japan were examined for infection with Rickettsia and Ehrlichia, by PCR and sequencing methodology. For Rickettsia, analysis of the partial sequence of the citrate synthase gene was successfully performed on 11 DNA samples from I. persulcatus, and 7 of them showed 99.8% identical with Rickettsia helvetica while the other 4 showed 99.8% identical with ;Candidatus Rickettsia tarasevichiae'. For Ehrlichia, a partial sequence of the 16S rRNA gene detected from I. persulcatus was 100% identical with that from Ehrlichia muris, and another DNA sample from I. ovatus showed 99.8% identical with Ehrlichia species detected from I. ovatus. The results suggest that the pathogens detected here might be distributed in this area.     

Occurrence and Distribution of Perfluorooctane Sulfonate and Perfluorooctanoic Acid in the Rivers of Tokyo

Comprehensive survey of major rivers in the Tokyo metropolitan area was conducted for clarifying the emission sources of perfluorooctane sulfonate (PFOS) in Tokyo. PFOS was found at all sampling sites at concentrations ranging from 0.5 to 58 ng L^?1; in addition to this, it was also indicated that unknown PFOS emission sources are present in the midstream of the Tama River basin. The relationship between PFOS and perfluorooctanoic acid (PFOA) was constant at a ratio of 10:3 (PFOS/PFOA) throughout the Tama River basin. The sum of daily load amounts of PFOS from Tokyo’s major rivers to Tokyo Bay reached 215 g day^?1. This value corresponds to 12.8 μg day^?1 per person using the sum of wastewater treatment district populations. In contrast, an estimation of PFOS contribution of domestic wastewater was also attempted, and the contribution was 1.6 μg day^?1 per person. We took samples up trunk sewers in the Tama River and finally found at the highest PFOS concentration (58,000 ng L^?1) from one of the wastewater of the electronic parts manufacturing facilities.     

Feeding habits of albacore Thunnus alalunga in the transition region of the central North Pacific

ABSTRACT:   The feeding habits of albacore Thunnus alalunga (fork length: 48.9–76.2 cm, n  = 132) were examined from late spring to early autumn in relation to its northward migration in the transition region between the subtropical and subarctic fronts in the central North Pacific. Samples were collected at night using surface gill nets or during daytime pole-and-line surveys in 2001 and 2002. During May and June, albacore fed mainly on Japanese anchovy Engraulis japonicus , which accounted for 27.2%, 67.0%, and 45.5% of the total stomach contents by number ( Cn ), wet weight ( WW ), and frequency of occurrence ( F ), respectively, and secondarily on the subarctic gonatid squid Gonatopsis borealis ( Cn , 15.8%; WW , 10.8%; F , 28.8%). From July to September, albacore continued to depend on Japanese anchovy ( Cn , 48.2–52.8%; WW , 79.9–95.2%; F , 27.8–85.4%). These results corresponded well with the remarkable rebound of the Japanese anchovy stock since the 1990s. Gonatopsis borealis , the main squid prey from May to June, almost disappeared from the stomachs of albacore from July to September, probably due to the northward migration of this squid to subarctic waters in summer. The feeding impact of albacore on the Japanese anchovy stock in the transition region was conservatively estimated to be from 1400 to 2100 tons per day from late spring to early autumn.     

Trail antigen in Eimeria stiedai sporozoites associated with a thrombospondin-related motif and the entry of cultured cells

In order to examine the antigenic similarity and specificity of the trail antigen of Eimeria stiedai and Etp 100, a microneme protein of Eimeria tenella, monoclonal antibodies to the trail antigen of E. stiedai sporozoites were selected by an indirect immunofluorescent antibody method. The monoclonal antibody of one clone, 3D10, reacted with the anterior portion of non-fixed sporozoites. By immunoblotting, the monoclonal antibody was found to react with a 100 kDa antigen of E. stiedai sporozoites, and a 117 kDa antigen of E. tenella sporozoites and merozoites. It was also found to react with a recombinant protein with thrombospondin-/properdin-like motifs homologous to E. tenella microneme protein Etp 100. The monoclonal antibody significantly inhibited the penetration of E. stiedai sporozoites into cultured rabbit hepatobiliary epithelial cells. These results suggest that E. stiedai sporozoites have a trail antigen, located in the anterior region on the outer surface of the sporozoites, which has an epitope with thrombospondin-/properdin-like motifs similar to E. tenella microneme protein Etp 100. This protein may play an important functional role in the process of penetration of host cells.     

Changes in serum thyroid hormone levels in newborn calves as a diagnostic index of endemic goiter

Maximum serum thyroxine (T4) and triiodothyronine (T3) levels of healthy calves were seen at 1 day after birth, and thereafter rapidly decreased until 5 days after birth. They stabilized until 2 weeks after birth, then gradually decreased until 4 weeks after birth. Serum T4 levels of calves with endemic goiter tended to be lower than those of healthy ones, but showed similar levels to those of adult cows. T3 levels of calves with goiter were similar to those of healthy ones, but showed higher variation. T4/T3 ratio of calves with goiter were significantly lower than those of healthy ones and adult cows. While individual levels of serum T4 and T3 at just after birth could not be considered as a diagnostic index, the T4/T3 ratio could be adopted as a diagnostic index of endemic goiter.     

Expression of mRNA of chemokine receptor CXCR4 in feline mammary adenocarcinoma

The expression of mRNA of the chemokine receptor CXCR4 in 65 surgically resected mammary adenocarcinomas from cats was investigated by in situ hybridisation. No expression of the receptor's mRNA was detectable in the mammary tissue of healthy cats, but it was expressed in areas adjacent to necrosis, surrounding blood vessels and cells infiltrating the lymphatics of 47 (72.3 per cent) of the 65 samples. There was a significant relationship between lymphatic infiltration by neoplastic cells and the expression of the receptor's mRNA (P < 0.005), but there was no significant relationship between its expression and the one-year survival of the cats.     

Molecular characteristics of cutaneous papillomavirus from the canine pigmented epidermal nevus

To investigate the relation between the canine pigmented epidermal nevus (PEN) and cutaneous papillomavirus, we cloned and sequenced the L1 gene of papillomavirus from the canine pigmented epidermal nevus (PEN). Amplification of DNA sample with the L1 consensus primers yielded an expected fragment of approximately 450-bp. The nucleotide sequences of the fragment showed about 64% of sequence similarity to the L1 region of human papillomavirus isolate CP6108 and less than 57% sequence similarity to those of canine oral papillomavirus (COPV). In situ hybridization determined the presence of papillomavirus DNA mainly in the upper stratum granulosum of skin in this case. The results indicated that the canine cutaneous papillomavirus from the PEN lesion was genetically close to human papillomavirus rather than COPV.     

Variations in transpiration rate and leaf cell turgor maintenance in saplings of deciduous broad-leaved tree species common in cool temperate forests in Japan

To clarify mechanisms underlying variation in transpiration rate among deciduous broad-leaved tree species, we measured diurnal changes in stomatal conductance (gs) and leaf water potential, and calculated the maximum transpiration rate (Emax), leaf-specific hydraulic conductance (K(s-l)) and difference between the soil water potential and the daily minimum leaf water potential (Psis - Psi(l,min)). Pressure-volume (P-V) measurements were made on leaves. Saplings of eight broad-leaved tree species that are common in Japanese cool temperate forests were studied. Maximum transpiration rate varied significantly among species. There was a statistically significant difference in Psis - Psi(l,min), but not in K(s-l). Species with large Emax also had large Psis - Psi(l,min) and gs. The results of the P-V analyses showed that species with a large Psis - Psi(l,min) maintained turgor even at low leaf water potentials. The similar daily minimum leaf pressure potentials (Psip) across all eight species indicate that Psip values below this minimum are critical. Based on these results, we suggest that the leaf cell capacity for turgor maintenance strongly affects Psis - Psi(l,min) and consequently Emax via stomatal regulation.