Central venous blood gas and acid-base status in conscious dogs and cats

To determine the reference level of central venous oxygen saturation (ScvO₂) and clinical efficacy of central venous blood gas analysis, partial pressures of oxygen and carbon dioxide, pH, oxygen saturation, base excess (B.E.) and HCO₃ concentration were compared between simultaneously obtained central venous and arterial blood samples from conscious healthy 6 dogs and 5 cats. Comparisons between arteriovenous samples were performed by a paired t-test and Bland-Altman analysis. Between arteriovenous samples, B.E. showed good agreement, but there were significant differences in other parameters in the dogs, and no good agreement was detected in cats. The ScvO₂ in dogs and cats were 82.3 ± 3.5 and 62.4 ± 13.5%, respectively. Central venous blood gas analysis is indispensable, especially in cats.     

The pharmacological effects of the anesthetic alfaxalone after intramuscular administration to dogs

The pharmacological effects of the anesthetic alfaxalone were evaluated after intramuscular (IM) administration to 6 healthy beagle dogs. The dogs received three IM doses each of alfaxalone at increasing dose rates of 5 mg/kg (IM5), 7.5 mg/kg (IM7.5) and 10 mg/kg (IM10) every other day. Anesthetic effect was subjectively evaluated by using an ordinal scoring system to determine the degree of neuro-depression and the quality of anesthetic induction and recovery from anesthesia. Cardiorespiratory variables were measured using noninvasive methods. Alfaxalone administered IM produced dose-dependent neuro-depression and lateral recumbency (i.e., 36 ± 28 min, 87 ± 26 min and 115 ± 29 min after the IM5, IM7.5 and IM10 treatments, respectively). The endotracheal tube was tolerated in all dogs for 46 ± 20 and 58 ± 21 min after the IM7.5 and IM10 treatments, respectively. It was not possible to place endotracheal tubes in 5 of the 6 dogs after the IM5 treatment. Most cardiorespiratory variables remained within clinically acceptable ranges, but hypoxemia was observed by pulse oximetry for 5 to 10 min in 2 dogs receiving the IM10 treatment. Dose-dependent decreases in rectal temperature, respiratory rate and arterial blood pressure also occurred. The quality of recovery was considered satisfactory in all dogs receiving each treatment; all the dog exhibited transient muscular tremors and staggering gait. In conclusion, IM alfaxalone produced a dose-dependent anesthetic effect with relatively mild cardiorespiratory depression in dogs. However, hypoxemia may occur at higher IM doses of alfaxalone.     

Na?ve-like conversion enhances the difference in innate in vitro differentiation capacity between rabbit ES cells and iPS cells

Quality evaluation of pluripotent stem cells using appropriate animal models needs to be improved for human regenerative medicine. Previously, we demonstrated that although the in vitro neural differentiating capacity of rabbit induced pluripotent stem cells (iPSCs) can be mitigated by improving their baseline level of pluripotency, i.e., by converting them into the so-called “naïve-like” state, the effect after such conversion of rabbit embryonic stem cells (ESCs) remains to be elucidated. Here we found that naïve-like conversion enhanced the differences in innate in vitro differentiation capacity between ESCs and iPSCs. Naïve-like rabbit ESCs exhibited several features indicating pluripotency, including the capacity for teratoma formation. They differentiated into mature oligodendrocytes much more effectively (3.3–7.2 times) than naïve-like iPSCs. This suggests an inherent variation in differentiation potential in vitro among PSC lines. When naïve-like ESCs were injected into preimplantation rabbit embryos, although they contributed efficiently to forming the inner cell mass of blastocysts, no chimeric pups were obtained. Thus, in vitro neural differentiation following naïve-like conversion is a promising option for determining the quality of PSCs without the need to demonstrate chimeric contribution. These results provide an opportunity to evaluate which pluripotent stem cells or treatments are best suited for therapeutic use.     

GM1 gangliosidosis in a Japanese domestic cat: a new variant identified in Hokkaido,Japan

A male Japanese domestic cat with retarded growth in Hokkaido, Japan, showed progressive motor dysfunction, such as ataxia starting at 3 months of age and tremors, visual disorder and seizure after 4 months of age. Finally, the cat died of neurological deterioration at 9 months of age. Approximately half of the peripheral blood lymphocytes had multiple abnormal vacuoles. Magnetic resonance imaging showed bisymmetrical hyperintensity in the white matter of the parietal and occipital lobes in the forebrain on T2-weighted and fluid-attenuated inversion recovery images, and mild encephalatrophy of the olfactory bulbs and temporal lobes. The activity of lysosomal acid β-galactosidase in leukocytes was negligible, resulting in the biochemical diagnosis of GM1 gangliosidosis. Histologically, swollen neurons characterized by accumulation of pale, slightly granular cytoplasmic materials were observed throughout the central nervous system. Dysmyelination or demyelination and gemistocytic astrocytosis were observed in the white matter. Ultrastructually, membranous cytoplasmic bodies were detected in the lysosomes of neurons. However, genetic analysis did not identify the c.1448G>C mutation, which is the single known mutation of feline GM1 gangliosidosis, suggesting that the cat was affected with a new variant of the feline disease.     

Evidence for the biosynthetic pathway from sinapic acid to syringyl lignin using labeled sinapic acid with stable isotope at both methoxy groups in Robinia pseudoacacia and Nerium indicum

A tracer experiment using synthesized labeled lignin precursors was designed to confirm the actual biosynthetic pathway for syringyl lignin. Tetradeuteroferulic acid-[8-D, 3-OCD(3)] and heptadeuterosinapic acid-[8-D, 3,5-OCD(3)] were synthesized and fed to shoots of robinia (Robinia pseudoacacia) and oleander (Nerium indicum) trees. The incorporation of each labeled precursor into lignin was traced by gas chromatography-mass spectrometry. The synthesized sinapic acid, in which both methoxy groups were labeled, was useful in monitoring the conversion of sinapic acid into syringyl lignin. When heptadeuterosinapic acid was fed, syringyl units containing seven deuterium labels were detected. The results of this study support the traditionally accepted pathway that sinapic acid is converted to sinapyl alcohol via sinapoyl-CoA in robinia and oleander.     

Effect of postactivation treatment with latrunculin a on in vitro and in vivo development of cloned embryos derived from kidney fibroblasts of an aged clawn miniature boar

The objective of this study was to examine the effect of postactivation treatment with latrunculin A (LatA), an actin polymerization inhibitor, on in vitro and in vivo development of somatic cell nuclear transfer (SCNT) embryos derived from kidney fibroblasts of an aged Clawn miniature boar (12 years old). After electric activation, SCNT embryos were treated with 0, 0.5 or 1 μM LatA and cultured in vitro. The rate of blastocyst formation was significantly higher (P<0.05) in SCNT embryos treated with 0.5 μM LatA (38%) than those in control (14%). When cloned embryos treated with 0.5 μM LatA were transferred into the oviducts of two recipient miniature gilts to assess their development in vivo, both recipients became pregnant; one maintained pregnancy to term, and a live piglet (weighing 220 g) was delivered by Caesarean section. The results of this study indicated that the postactivation treatment with LatA was effective in improving in vitro developmental capacity of SCNT miniature pig embryos derived from kidney fibroblasts of an aged animal and that miniature pig cloned embryos treated with LatA had the ability to develop to term.     

Stage‐specific effects of osmolarity of a culture medium on development of pig oocytes and miniature pig somatic cell nuclear transfer embryos activated by ultrasound treatment

Whether high osmolarity of a culture medium at the early culture stage affects the development of pig oocytes and miniature pig somatic cell nuclear transfer (SCNT) embryos activated by ultrasound was examined. When oocytes were cultured in modified porcine zygote medium‐3 (mPZM‐3) with increased NaCl to 138 mmol/L (mPZM‐3+NaCl; 326 mOsm) or 50 mmol/L sucrose (mPZM‐3+sucrose; 318 mOsm) for the first 2 days and then cultured in normal mPZM‐3 (273 mOsm) for 5 days, the cleavage and blastocyst formation rates were significantly (P < 0.05) higher than those of oocytes cultured in mPZM‐3 for 7 days. The cleavage and blastocyst formation rates of SCNT embryos cultured in mPZM‐3+NaCl for the first 2 days and then cultured in mPZM‐3 for 5 days were also significantly (P < 0.05) higher than those of embryos cultured in mPZM‐3 for 7 days. These results showed that the high osmolarity of a culture medium induced by increasing NaCl concentration during the first 2 days improves the development of pig oocytes and miniature pig SCNT embryos activated by ultrasound.