Immunohistochemical localization of steroidogenic enzymes in the testis of Hokkaido Sika deer (Cervus nippon yesoensis)

The testes from 15 adult male Hokkaido Sika deer (Cervus nippon yesoensis) were collected during the rutting season (October and November). We investigated the localization of 4 kinds of steroidogenic enzymes (P450scc, 3betaHSD, P450c17 and P450arom) immunohistochemically in these testicular samples. The specific immunoreactivities to these enzymes were detected only in the cytoplasm of Leydig cells. This differs to the enzyme distributions reported previously in Japanese black bear, Japanese raccoon dog, Hokkaido brown bear and American black bear, in which the same immunoreactivities were detected in Leydig cells, Sertoli cells and/or spermatogenic cells. The current study suggests that in the testes of the Hokkaido Sika deer, testosterone and estradiol-17beta may be synthesized in the Leydig cells only.     

Plasma biochemical reference values in clinically healthy captive bearded dragons (Pogona vitticeps) and the effects of sex and season

Background: Bearded dragons are one of the most popular pet lizard species, and biochemical reference values are useful for health management of these reptiles. Objectives: The objectives of this study were to measure plasma biochemical values in healthy captive bearded dragons, determine reference values, and evaluate the effects of sex and season on the results. Methods: Blood samples were collected from 100 captive healthy bearded dragons in Tokyo during the summer and winter. Plasma biochemical measurements were performed using a dry‐slide automated biochemical analyzer. The data were then compared based on sex and season using 2‐way ANOVA. Results: Globulin, cholesterol, and calcium concentrations of females were higher in both summer and winter compared with the values obtained for males. Both males and females had higher uric acid concentrations in winter than in summer. When compared with males, females had a higher chloride concentration in summer and a higher total protein concentration and aspartate aminotransferase activity in winter. Potassium concentration in males was lower in winter than in summer, whereas in females cholesterol concentration was lower in winter than in summer. Conclusions: Biochemical values that differed based on sex and season in bearded dragons were similar to those in other lizards. These differences reflect physiologic differences in reproductive status in females and seasonal changes in temperature and hydration status. Plasma biochemical values established for bearded dragons in this study will be useful in the diagnostic assessment of captive animals.     

Attaining inter-subgeneric hybrids in fragrant azalea breeding and the inheritance of organelle DNA

Inter-subgeneric hybrids were successfully obtained in reciprocal cross combinations between evergreen azaleas (Rhododendron nakaharae and its hybrids) and fragrant deciduous azaleas (R. arborescens and R. viscosum) for the purpose of fragrant evergreen azalea breeding. Nuclear and organelle DNA of these hybrids was investigated using PCR-RFLP markers. Viable hybrid seedlings have nuclear ribosomal DNA (nrDNA) inherited biparentally, mitochondrial DNA (mtDNA) from the seed parent, and chloroplast DNA (cpDNA) from the deciduous azalea, regardless of cross combination. These results suggest that the chloroplast genome from deciduous azaleas and the nuclear genome from evergreen azaleas are compatible in viable hybrid progenies.     

Pharmacokinetics of single‐dose sildenafil administered orally in clinically healthy dogs: Effect of feeding and dose proportionality

Basic information related to the pharmacokinetics of sildenafil in dogs is scarce. This study aimed to describe the pharmacokinetic properties of oral sildenafil and determine the effect of feeding and dose proportionality. The effect of feeding on pharmacokinetics of sildenafil (1 mg/kg) was investigated using a crossover study with six dogs. In addition, the dose proportionality of sildenafil ranging 1–4 mg/kg was evaluated using five dogs in the fasted states. The plasma concentrations of sildenafil were determined using high‐performance liquid chromatography, and pharmacokinetic parameters were calculated using a noncompartmental analysis. Sildenafil administrations were well tolerated in all studies. Feeding reduced the area under the curve extrapolated to infinity (AUC_inf) and the maximum plasma concentration (C_max) significantly. The elimination half‐life (T_1/2) did not differ between the fasted and the fed states. For dose proportionality, nonproportional increases in AUC_inf and C_max at 1–4 mg/kg doses were detected by a power model analysis.     

Chimeric inheritance of organelle DNA in variegated leaf seedlings from inter-subgeneric crossing of azalea

The inheritance of organelle DNA was investigated using PCR–RFLP markers in reciprocal cross combinations of inter-subgeneric azalea hybrids between evergreen azaleas (Rhododendron nakaharai and its hybrids) and fragrant deciduous azaleas (R. arborescens and R. viscosum) for the purpose of breeding fragrant evergreen azaleas. The hybrid progenies included green leaf, pale green leaf, variegated leaf and albino seedlings. Most viable green leaf seedlings had inherited ptDNA from the deciduous parent and non-viable albino and pale green leaf seedlings had inherited ptDNA from the evergreen parent. On the other hand, variegated leaf seedlings had chimerically inherited ptDNA from both parents. Their green leaf segments had ptDNA from the deciduous parent, and the pale green and white segments had biparental or maternal ptDNA depending on the progeny. In this study, we obtained interesting inter-subgeneric azalea hybrid progenies that had chimerically inherited organelle DNA and had different colored leaf segments corresponding to the composition of ptDNA from each parent. These results suggest that variegated leaf progenies with chimeric ptDNA from both parents can be subsistent, whereas albino seedlings resulting from plastome–genome incompatibility between the plastid genome from evergreen azalea and the nuclear genome from deciduous azalea are non-viable.     

Evaluation of the Autonomic Nervous System in a Canine Model of Chronic Embolic Pulmonary Hypertension

Veterinary Research Communications - Sildenafil improves autonomic dysfunction caused by pulmonary hypertension (PH) in humans, but its effect is unknown in dogs with PH. This prospective study...     

Expression of prostaglandin F(2α) (PGF(2α)) receptor and its isoforms in the bovine corpus luteum during the estrous cycle and PGF(2α)-induced luteolysis

Prostaglandin F(2α) (PGF(2α)) induces luteolysis via a specific receptor, PTGFR. Although PTGFR mRNA expression in the bovine corpus luteum (CL) has been studied previously, changes in PTGFR protein and its localization are not fully understood during the life span of the CL. In addition to full-length PTGFR, several types of PTGFR isoforms, such as PTGFRα (type I) and PTGFRζ (type II), were reported in the bovine CL, suggesting isoform-specific luteal action. Full-length PTGFR mRNA in the bovine CL increased from the early to the mid-luteal phase and decreased during luteolysis, whereas PTGFR protein remained stable. PTGFR protein was localized to both luteal and endothelial cells and was expressed similarly during the life span of the CL. Like full-length PTGFR mRNA, PTGFRα and PTGFRζ mRNA also increased from the early to mid-luteal phases, and mRNA of PTGFRζ, but not PTGFRα, decreased in the regressing CL. During PGF(2α)-induced luteolysis, the mRNAs of full-length PTGFR, PTGFR,α and PTGFRζ decreased rapidly (from 5 or 15 min after PGF(2α) injection), but PTGFR protein decreased only 12 h later. Silencing full-length PTGFR using small interfering RNA prevented PGF(2α)-stimulated cyclooxygenase-2 (PTGS2) mRNA induction. By contrast, PGF(2α) could stimulate vascular endothelial growth factor A (VEGFA) mRNA even when full-length PTGFR was knocked down, thus suggesting that PGF(2α) may stimulate PTGS2 via full-length PTGFR, whereas VEGFA is stimulated via other PTGFR isoforms. Collectively, PTGFR protein was expressed continually in the bovine CL during the estrous cycle, implying that PGF(2α) could function throughout this period. Additionally, the bovine CL expresses different PTGFR isoforms, and thus PGF(2α) may have different effects when acting via full-length PTGFR or via PTGFR isoforms.     

Evaluation of the inhibitory effects of telmisartan on drug-induced renin-angiotensin-aldosterone system activation in normal dogs

Introduction

This study examined whether the angiotensin II receptor blocker telmisartan had inhibitory effects on drug-induced renin-angiotensin-aldosterone system (RAAS) activation in normal dogs.

Appearance of albino seedlings and ptDNA inheritance in interspecific hybrids of azalea

PCR-RFLP analysis was conducted to clarify the relationship between the leaf color of progenies and their ptDNA inheritance in interspecific three-way crosses, (Rhododendron kiusianum × R. eriocarpum) × R. japonicum f. flavum. All albino progenies contained maternal ptDNA, whereas green and pale-green progenies contained paternal ptDNA. Sectorial chimeric progenies, of which the leaf and shoot color was turned from green to albino during the culture, contained both maternal and paternal ptDNA in green segments and maternal ptDNA in albino segments. These results suggest that albino progenies are caused by the incompatibility between plastome from F₁ hybrids of R. kiusianum × R. eriocarpum and nuclear genome from R. japonicum f. flavum. This revised version was published online in August 2006 with corrections to the Cover Date.