Effect of the timing of first cleavage on in vitro developmental potential of nuclear-transferred bovine oocytes receiving cumulus and fibroblast cells

The aim of the present study was to examine whether cumulus and fibroblast cell nuclear-transferred oocytes, which have high and low potential to develop into normal calves, respectively, are different in terms of in their patterns of timing of first cleavage and in their relationships between timing of first cleavage and in vitro developmental potential. The timing of first cleavage was similar in both types of nuclear-transferred and in vitro fertilized oocytes. More than 86% of the oocytes cleaved within 24 h after activation or in vitro fertilization; these oocytes contributed to more than 98% of the total number of blastocysts in all three groups. The potential of oocytes that cleaved at different intervals to develop into blastocysts differed among the groups. The developmental potential of the cumulus cell nuclear-transferred oocytes and in vitro fertilized oocytes decreased with the increase in time required for cleavage. Fibroblast cell nuclear-transferred oocytes that cleaved at 20 h, an intermediate cleaving time, had higher potential to develop into blastocysts. The results of the present study suggest that the type of donor nucleus used for nuclear transfer affects the timing of first cleavage.     

Fibrodysplasia ossificans progressiva-like condition in a cat

Fibrodysplasia ossificans progressiva (FOP)-like condition was diagnosed in a Japanese domestic cat with stiffness, marked atrophy of the muscles, and limited mobility of all joints in both the pelvic limbs. Etretinate, a retinoid, was used for medical management; however, no improvement in the clinical signs was observed. Inheritance of the disorder has not yet been demonstrated. Furthermore, the clinical signs and histopathological findings of feline FOP-like condition in the present case differed from those of the previously reported cases.     

Spectral analysis of heart rate variability in dogs with mild mitral regurgitation

OBJECTIVE: To assess autonomic function in dogs with mild mitral regurgitation (MR) that did not have clinical signs of the condition. ANIMALS: 6 healthy adult Beagles. PROCEDURE: Mild MR was experimentally induced. A 24-hour ambulatory ECG was recorded before and after induction of MR. Heart rate variability was analyzed in frequency domains by use of the ambulatory ECG. Low-frequency (LF) and high-frequency (HF) power were calculated by integrating over their frequency intervals, and the ratio of LF to HF was also calculated. Measurements of frequency domains were analyzed for 4 time periods (midnight to 6 AM, 6 AM to noon, noon to 6 PM, and 6 PM to midnight). RESULTS: Dogs with experimentally induced MR were classified as International Small Animal Cardiac Health Council class Ia. The HF power of dogs with MR was significantly decreased between 6 AM and noon. The ratio of LF to HF in dogs with MR was significantly increased for the periods between midnight and 6 AM, 6 AM and noon, and noon and 6 PM. CONCLUSIONS AND CLINICAL RELEVANCE: Compensatory response through autonomic modulation was observed in dogs with mild MR that did not have abnormalities, except for cardiac murmur, during clinical examination. This result suggests that treatment during the early stages of mild MR may be beneficial. Additional studies are necessary to determine whether such treatment will delay the onset of congestive heart failure and prolong survival in dogs affected with mild MR.     

Development of a new selective medium for isolation of methicillin-resistant Staphylococcus aureus

A new selective medium containing cephem antibiotics was developed for isolation of methicillin-resistant Staphylococcus aureus (MRSA). MRSA colonies on a medium containing ceftazidime (CAZ) were most easily identifiable and a medium containing cefoperazone (CPZ) was superior in suppressing the growth of other bacteria. With the medium containing a couple of CAZ and CPZ, MRSA and methicillin-resistant coagulase-negative staphylococci (MRCNS) were detected from 2 and 1 of 15 chicken meat samples respectively. The MRSA and MRCNS recovery test showed that the medium was effective for MRSA isolation, suppressing the growth of other bacteria efficiently. These results suggested that the medium containing a couple of CAZ and CPZ was useful for MRSA detection from foods and animals.