Effect of mitotane on pituitary corticotrophs in clinically normal dogs

OBJECTIVE: To evaluate the effects of mitotane administration on the function and morphology of pituitary corticotrophs in clinically normal dogs. ANIMALS: 12 clinically normal adult Beagles. PROCEDURES: Dogs were randomly assigned to the control group or the mitotane treatment group. In mitotane treatment group dogs, mitotane was administered for 1 month. In both groups, ACTH stimulation testing and corticotrophin-releasing hormone (CRH) stimulation testing were performed. Magnetic resonance imaging (MRI) of the pituitary gland and brain was performed in mitotane treatment group dogs before and after administration of mitotane. After CRH stimulation testing and MRI, dogs were euthanatized and the pituitary gland and adrenal glands were excised for gross and histologic examination. RESULTS: ACTH concentrations in mitotane treatment group dogs were significantly higher than in the control group dogs following CRH stimulation. Magnetic resonance imaging revealed that pituitary glands were significantly larger in treatment group dogs after administration of mitotane, compared with before administration. On gross and histologic examinations, the adrenal cortex was markedly atrophied. Immunohistochemistry revealed hypertrophy of corticotrophs in pituitary glands of mitotane treatment group dogs. CONCLUSIONS AND CLINICAL RELEVANCE: These findings indicate that inhibition of the adrenal cortex by continuous administration of mitotane leads to functional amplification and morphologic enhancement of corticotrophs in clinically normal dogs. In instances of corticotroph adenoma, hypertrophy of individual corticotrophs induced by mitotane may greatly facilitate enlargement of the pituitary gland and increases in ACTH secretion.     

Neuronal pathway from the liver modulates energy expenditure and systemic insulin sensitivity

Coordinated control of energy metabolism and glucose homeostasis requires communication between organs and tissues. We identified a neuronal pathway that participates in the cross talk between the liver and adipose tissue. By studying a mouse model, we showed that adenovirus-mediated expression of peroxisome proliferator-activated receptor (PPAR)-g2 in the liver induces acute hepatic steatosis while markedly decreasing peripheral adiposity. These changes were accompanied by increased energy expenditure and improved systemic insulin sensitivity. Hepatic vagotomy and selective afferent blockage of the hepatic vagus revealed that the effects on peripheral tissues involve the afferent vagal nerve. Furthermore, an antidiabetic thiazolidinedione, a PPARg agonist, enhanced this pathway. This neuronal pathway from the liver may function to protect against metabolic perturbation induced by excessive energy storage.     

A voltage sensor-domain protein is a voltage-gated proton channel

Voltage-gated proton channels have been widely observed but have not been identified at a molecular level. Here we report that a four-transmembrane protein similar to the voltage-sensor domain of voltage-gated ion channels is a voltage-gated proton channel. Cells overexpressing this protein showed depolarization-induced outward currents accompanied by tail currents. Current reversal occured at equilibrium potentials for protons. The currents exhibited pH-dependent gating and zinc ion sensitivity, two features which are characteristic of voltage-gated proton channels. Responses of voltage dependence to sequence changes suggest that mouse voltage-sensor domain-only protein is itself a channel, rather than a regulator of another channel protein.     

Effect of supplemented sericin on the development,cell number,cryosurvival and number of lipid droplets in cultured bovine embryos

Sericin was investigated as an alternative to fetal bovine serum (FBS) for bovine embryo culture. In vitro matured oocytes were developed using 0.05%, 0.1% or 0.15% sericin. The developmental rate, cryosurvival rate and blastulation time of these embryos were compared with those of embryos developed using 5% FBS. The number of lipid droplets was compared among the blastocysts developed using 5% FBS, using 0.05% sericin and in vivo. The rate of cleavage and blastocyst formation was similar among all groups. Blastulation occurred significantly earlier in the embryos developed using 5% FBS than in those developed using sericin at any concentration (P < 0.05). At 72 h after thawing, the cryosurvival rate of the blastocysts developed using 5% FBS and 0.05% sericin were significantly higher compared with those developed using 0.1% and 0.15% sericin (P < 0.05). The blastocysts developed using 0.05% sericin and in vivo produced a significantly fewer number of medium and large lipid droplets than those developed using 5% FBS. These results suggest that the blastocysts developed using 0.05% sericin show characteristics similar to those of the blastocysts developed in vivo and that the use of sericin as an alternative to FBS is feasible.     

Evaluation of the genetic structure of sika deer (Cervus nippon) in Japan's Kanto and Tanzawa mountain areas,based on microsatellite markers

The browsing habits of sika deer (Cervus nippon) in Japan have caused serious ecological problems. Appropriate management of sika deer populations requires understanding the different genetic structures of local populations. In the present study, we used 10 microsatellite polymorphisms to explore the genetic structures of sika deer populations (162 individuals) living in the Kanto region. The expected heterozygosity of the Tanzawa mountain range population (Group I) was lower than that of the populations in the Kanto mountain areas (Group II). Our results suggest that moderate gene flow has occurred between the sika deer populations in the Kanto mountain areas (Group II), but not to or from the Tanzawa mountain range population (Group I). Also, genetic structure analysis showed that the Tanzawa population was separated from the other populations. This is probably attributable to a genetic bottleneck that developed in the Tanzawa sika deer population in the 1950s. However, we found that the Tanzawa population has since recovered from the bottleneck situation and now exhibits good genetic diversity. Our results show that it is essential to periodically evaluate the genetic structures of deer populations to develop conservation strategies appropriate to the specific structures of individual populations at any given time.     

Effects of climate change on reduction of internal bond strength of particleboard subjected to various climatic conditions in Japan

The effects of climate change on the reduction of internal bond strength (IB) of particleboard subjected to various climatic conditions in Japan were predicted. The temperature increased throughout Japan with increasing greenhouse gas (GHG) emissions, so the climate deterioration index (climate index for predicting the IB reduction of particleboard; a high index indicates a large IB reduction) also increased to decrease IB. The number of low-temperature areas decreased because of climate change. The rupture of bonding points in particleboard caused by outdoor exposure led to a IB reduction, and biodeterioration accelerated this reduction. In high-temperature areas, particleboard was found to be prone to biodeterioration, and the IB significantly reduced. An area wherein there was a significant decrease in the IB spread along the Pacific Ocean side of western Japan and the Sea of Japan in central Japan in relation to increasing GHG emissions. Particleboards are difficult to use outdoors because of climate change.     

草炭风化炭改良盐碱土的生态效应研究

采用草炭和风化炭进行改良盐碱土的盆栽试验.结果表明,施用草炭、风化炭使土壤盐分略有上升,主要使Ca2+和Na+增加;土壤有机质含量因草炭、风化炭的施用而增加,且与有机物料的用量呈正相关关系;土壤速效氮、速效磷、速效钾含量也均随有机物料的施用而增加.水稻株高、穗长和每穗粒数均有所增加,水稻籽实产量显著提高.     

Seasonal distribution of adult crucian carp nigorobuna <Emphasis Type="Italic">Carassius auratus grandoculis</Emphasis> and gengoroubuna <Emphasis Type="Italic">Carassius cuvieri</Emphasis> in Lake Biwa,Japan

Seasonal habitat use by nigorobuna Carassius auratus grandoculis Temminck et Schlegel and gengoroubuna Carassius cuvieri (Temminck et Schlegel) in Lake Biwa was investigated using acoustic telemetry. Twenty-three nigorobuna and 11 gengoroubuna specimens caught using set-nets in the lake’s south basin were surgically fitted with acoustic transmitters and then released. Signals from the fishes were recorded by 23 receivers installed around the lake. Between April and June 2007, the first spawning season after release, signals were received from all tagged fishes. Thereafter, until the second spawning season, signals were collected from 26 and 45% of released nigorobuna and gengoroubuna individuals, respectively. Seasonal habitat preferences for these species were studied by distance-based analysis. The analysis revealed that nigorobuna tended to stay near their spawning area in the south basin of the lake throughout the year, whilst gengoroubuna tended to show a seasonal migration pattern between the north and south basins. After the spawning season, the latter species migrated to the north basin where it remained until the next spawning season, when it returned to the south basin. This is the first report of seasonal migration of nigorobuna and gengoroubuna in Lake Biwa.     

Molecular Structure and Some Physicochemical Properties of Buckwheat Starches

The molecular structure and pasting properties of starches from eight buckwheat cultivars were examined. Rapid viscograms showed that buckwheat starches had similar pasting properties among cultivars. The actual amylose content was 16–18%, which was lower than the apparent amylose content (26–27%), due to the high iodine affinity (IA) of amylopectin (2.21–2.48 g/100 g). Amylopectins resembled each other in average chain‐length (23–24) and chain‐length distributions. The long‐chains fraction (LC) was abundant (12–13% by weight) in all the amylopectins, which was consistent with high IA values. The amyloses were also similar among the cultivars in number‐average DP 1,020–1,380 with 3.1–4.3 chains per molecule. The molar‐based distribution indicated that all the amyloses comprised two molecular species differing in molecular size, although the weight‐based distribution showed a single species. A comparison of molecular structures of buckwheat starches to cereal starches indicated buckwheat amylopectins had a larger amount of LC, and their distributions of amylose and short chains of amylopectin on molar basis were similar to those of wheat and barley starches.     

Fine Structures of Amylose and Amylopectin from Large,Medium, and Small Waxy Barley Starch Granules

Amylose and amylopectin were prepared from large, medium, and small granule starches of classified waxy barley flour, and their fine structures were investigated. The amylose content had a wide distribution range (≈1.4–9.4%). Number‐average degrees of polymerization (DP_n) of the amyloses were similar among the samples (≈1,200–1,300). But number of chains per molecule (NC) decreased from the surface to the center (≈6–10 chains). DP_n of the amylopectins varied from 4,657 to 14,604; decreased in the order of large, medium, and small granules in same fractions of the grain; and increased from the surface layer to the center. Longest chains (LC) were not found in any of the amylopectin molecules. The large amylopectin molecule had more long chains and fewer A chains than the small molecule. The amylose content had definite effects on the transition temperature range and crystal formation of the starch granules. There were positive correlations between DP_n of the amylopectin and relative crystallinity (γ = +0.69) and enthalpy value (γ = +0.80), respectively. These findings may help to elucidate biosynthesis mechanism of starch.