Regional variability in landscape effects on forest bird communities

Landscape Ecology - Functional responses to landscape heterogeneity are context-dependent, hampering the transferability of landscape-scale conservation initiatives. Japan provides a unique...     

Comparison of cholesterol levels among lipoprotein fractions separated by anion-exchange high-performance liquid chromatography in periparturient Holstein–Friesian dairy cows

Changes in lipoprotein profiles occur in dairy cows during the periparturient period and in cows with transition cow disease. Here, the lipoprotein profiles of Holstein–Friesian dairy cows during the periparturient period were obtained by anion-exchange, high-performance liquid chromatography to evaluate the usefulness of lipoprotein profile evaluation during the periparturient period and in cows with fatty liver and milk fever. Lipoprotein levels (including total and high- (HDL-C) and low-density lipoprotein (LDL-C) cholesterol) in 10 healthy cows were low 4 weeks prepartum, with the lowest values at calving or within 1 week of calving; the values increased at 8 weeks postpartum. The lipoprotein levels were measured in 16 cows diagnosed with fatty liver (n=10) or milk fever (n=6) and compared to 10 healthy dairy cows. A significant difference was observed in HDL-C between healthy cows (at calving and 1 week postpartum), and the fatty liver and milk fever cows. Cows with fatty liver and milk fever had a lower mean HDL-C than the 10 healthy dairy cows at calving and 1 week postpartum. HDL-C might be a good indicator of energy balance for differentiating healthy cows from those with transition cow disease.     

Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows

Blood samples were obtained sequentially from 10 dairy cows around the time of parturition to assess plasma fluctuations in estradiol-17β (E₂) levels in association with those of several bone resorption markers. Plasma E₂ concentration increased sharply a few days prepartum and decreased quickly after parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and was maintained at this level to a few days postpartum. The plasma concentration of carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly after parturition. These observations suggest that osteoclast-mediated bone resorption was activated after parturition when plasma E₂ concentrations decreased.     

Accessory corpora lutea formation in pregnant Hokkaido sika deer (Cervus nippon yesoensis) investigated by examination of ovarian dynamics and steroid hormone concentrations

Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation.     

Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa.     

Parathyroid hormone‐related protein‐induced hypercalcemia due to osteosarcoma in a cat

A 15‐year‐old castrated male mixed‐breed cat was presented with a history of sarcoma of the distal right hind limb. Biochemical analysis revealed increased concentrations of blood urea, creatinine, total calcium, ionized calcium, and parathyroid hormone‐related protein (PTHrP). The mass was removed surgically by amputation of the hind limb. Osteosarcoma was diagnosed based on histopathologic examination. All abnormal serum analyte concentrations improved immediately after surgery, including azotemia, total calcium, ionized calcium, and PTHrP. The biochemical results were attributed to osteosarcoma causing PTHrP‐induced hypercalcemia.     

Pharmacokinetics of metoclopramide in calves with renal dysfunction

To clarify the effect of renal dysfunction on pharmacokinetics of the prokinetic agent metoclopramide (MCP), we administered intravenously 0.4 mg/kg MCP to healthy calves and calves subjected to right kidney vessel ligation (ligation) without or with a subsequent left nephrectomy (ligation plus removal). Plasma MCP concentration, glomerular filtration rate (GFR) and plasma prolactin level were measured by liquid chromatography-tandem mass spectrometry, simplified equation using iodixanol and enzyme-linked immunosorbent assay, respectively. Only in calves with ligation plus removal, plasma MCP concentrations were increased significantly 6, 8 and 12 hr after injection, showing that a negative correlation was observed between the plasma MCP concentrations and GFR value. A tendency to increase in plasma PRL concentration was noted also in these calves. In conclusions, plasma MCP concentrations depend on the GFR mode in calves, and its critical GFR value was estimated.