Thyroid hormone augments GLUT4 expression and insulin-sensitive glucose transport system in differentiating rat brown adipocytes in culture

The effects of triiodothyronine (T3) on differentiation-dependent expression of GLUT and responses of glucose transport to insulin and norepinephrine (NE) were investigated. Precursor cells of brown adipocytes isolated from the interscapular brown adipose tissue of newborn rats were cultured in the absence or presence of various concentrations of T3. Western bolt analysis revealed that treatment with T3 resulted in an increased expression of GLUT4, in a dose-dependent manner, whereas GLUT1 contents were unchanged. In parallel with the increase in GLUT4 expression, T3 improved insulin sensitivity for glucose transport, being accompanied by an increase in maximal transport rate and a reduction of ED(50). In contrast, T3-treatment of the brown adipocytes during the differentiation process had little effect on NE-regulatable glucose transport system. These results suggest that T3 plays a predominant role in the development of insulin-sensitive glucose transport during differentiation of brown adipocytes.     

Steroid hormones do not reactivate Neospora caninum in ovariectomized mice

The direct effects of three steroid hormones (progesterone, estradiol-17beta and corticosterone) on the growth of Neospora caninum (N. caninum) tachyzoite were examined in Vero cells. Subsequently, ovariectomized BALB/c mice infected with N. caninum were treated with physiological concentrations of the steroid hormones for 1 or 2 weeks. These hormones had no direct effect on the parasite growth in vitro. In the infected mice, there was no significant difference in the parasite distribution and histopathological changes between the hormone-injected and control groups. No mice showed parasitemia at the time of autopsy. These results suggest that physiological levels of steroid hormones (progesterone, estradiol-17beta and corticosterone) do not reactivate N. caninum in mice.     

Post-exposure treatment of cats with mouse-cat chimeric antibodies against feline herpesvirus type 1 and feline calicivirus

In order to confirm the in vivo effectiveness of anti- feline herpesvirus type 1 (FHV-1) mouse-cat chimeric antibody (FJH2), and anti-feline calicivirus (FCV) mouse-cat chimeric antibody (F1D7), cats that had been experimentally infected with FHV-1 or FCV were administered intravenously with the chimeric antibodies, and observed for clinical manifestations. The symptoms due to FHV-1 or FCV infection in the cats administered FJH2 or F1D7 were obviously decreased when compared with those of the non-administered control cats. From these results, it was confirmed that both FJH2 and F1D7 were effective at reducing the appearance of symptoms due to FHV-1 and FCV infection, respectively.     

Interaction of dinotefuran and its analogues with nicotinic acetylcholine receptors of cockroach nerve cords

To investigate the action of dinotefuran (MTI-446, 1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine), a recently developed insecticide, on insect nicotinic acetylcholine receptors (nAChRs), we determined the potencies of the compound and 15 analogues in inhibiting the specific binding of [3H]epibatidine (EPI), a nAChR agonist, and [3H]alpha-bungarotoxin (alpha-BGT), a competitive nAChR antagonist, to the nerve cord membranes of American cockroaches (Periplaneta americana). Racemic dinotefuran inhibited [3H]EPI binding with an IC50 of 890 nM and [3H]alpha-BGT binding with an IC50 of 36.1 microM. Scatchard analysis indicated that the dinotefuran inhibition of [3H]EPI binding was a competitive one. Slight structural modification caused a drastic reduction in potency; only four analogues were found to be equipotent to or more potent than dinotefuran. Chloropyridinyl and chlorothiazolyl neonicotinoid insecticides displayed two or three orders of magnitude higher potency than dinotefuran. There was a good correlation between the IC50 values of tested compounds obtained with [3H]EPI and those obtained with [3H]alpha-BGT. A better correlation was observed between 3-h knockdown activities (KD50) against German cockroaches (Blattella germanica) and IC50 values obtained from [3H]EPI assays than between 24-h lethal activities (LD50) and IC50 values. While the results indicate that dinotefuran and its analogues interact with the ACh-binding site in cockroach nAChRs, it remains to be elucidated why they displayed lower potencies than those expected based on their insecticidal activities.     

The renal structure in an Asian elephant (Elephas maximus)

The renal structure of a female Asian elephant (Elephas maximus) was observed in both macroscopic and light microscopic levels. The left kidney was elongated-ellipse in shape, whereas the right appeared round. The left kidney was 31 cm in cranio-caudal length, 21 cm in medio-lateral length, and 2950 g in weight. The right kidney was 34 cm in cranio-caudal length, 22 cm in medio-lateral length, and 3250 g in weight. The external appearance showed the six separated renal lobes in both sides of the kidney. The four pairs of the lobes were fused in the deepest region in both sides of kidney, so we considered it as an incompletely lobated kidney in this species. We observed the proximal and distal urinary tubules in histological sections. Many renal corpuscles consisted of the glomerulus and Bowman's capsule. Many mesangial cells and some podocytes were confirmed in each glomerulus; however, Bowman's capsules were larger than those in other mammalian species.     

Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles

The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus), the false gavial (Tomistoma schlegelii), and the African slender-snouted crocodile (Mecistops cataphractus) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been consistent with both the Indian and false gavials.     

On the morphology of the liver in the two-humped camel (Camelus bactrianus)

The liver of a two-humped camel (Camelus bactrianus) was examined by means of gross anatomy and histology. The liver appeared characteristically as an enlarged triangle in visceral aspect, and showed the following lobation: the left lateral and medial lobes, the right lobe, the caudate lobe and the quadrate lobe. These findings were similar to those for the one-humped camel. Histologically, a distinct lobulation, a typical arrangement of the interlobular connective tissue, and the trias was confirmed.     

Geographical variation of mandible size and shape in the Japanese wild pig (Sus scrofa leucomystax)

The mandibles of the Japanese wild pigs (Sus scrofa leucomystax) from various geographical locations, which have been stored in the University of Tokyo and National Science Museum, Tokyo were examined. The mandibles from northern localities were larger in size than those from southern localities. The Oita population was significantly smaller than the Honshu populations. The Mie population was smaller than the Hyogo population in length from the angle of the mandible. In the multivariate analysis, the Kyushu populations could be obviously distinguished from the Honshu populations in the principal component charts. However, each Honshu population did not show the locality-specific distribution of the principal component plots.     

Sympatric distribution of the two morphological types of the common tree shrew in Hat-Yai districts (South Thailand)

The two color types (grayish northern and reddish southern types) of the common tree shrew (Tupaia glis and Tupaia belangeri) were co-distributed in Hat-Yai region (South Thailand). Although the Isthmus of Kra in South Thailand has been considered as distribution barrier of the two types, the sympatric distribution of both types was confirmed in southern side of the Isthmus. In the principal component analysis, the skull measurement character from Hat-Yai region could also be separated into the northern and southern groups according to the skin color identification of corresponding individuals. We could generally distinguish the common tree shrew into two types by skull morphology as well as external skin color.