Effects of pimobendan for mitral valve regurgitation in dogs

Pimobendan has a dual mechanism of action: it increases myocardial contractility by increasing calcium sensitization to troponin C and it promotes vasodilation by inhibiting PDEIII. This study examined the effects of pimobendan on cardiac function, hemodynamics, and neurohormonal factors in dogs with mild mitral regurgitation (MR). The dogs were given 0.25 mg/kg of pimobendan orally every 12 hr for 4 weeks. With pimobendan, the heart rate and stroke volume did not change, but the systolic blood pressure gradually decreased and the degree of mitral valve regurgitation tended to decrease. Renal blood flow was significantly increased and the glomerular filtration rate was slightly increased at 2 and 4 weeks. Furthermore, over the 4-week period, the plasma norepinephrine concentration decreased significantly, the systolic index increased slightly, the left atrial diameter and the left ventricular diameters decreased significantly, and the heart size improved. Given these results, pimobendan appears to be useful for treating MR in dogs. However, further long-term studies of pimobendan involving a larger number of dogs with mild and moderate MR are needed to establish the safety of pimobendan and document improvements in quality of life.     

Evaluation of left ventricular Tei index (index of myocardial performance) in healthy dogs and dogs with mitral regurgitation

The left ventricular (LV) Tei index (index of myocardial performance) has been demonstrated to be clinically useful in estimating comprehensive LV function, including the systolic and diastolic performances, in various human cardiac diseases. The purposes of this study were to validate the correlation between the LV Tei index and LV function obtained by cardiac catheterization in healthy dogs, and to evaluate the LV Tei index in dogs with naturally occurring mitral regurgitation (MR). In healthy dogs, the LV Tei index was significantly correlated with the LV peak +dP/dt (r = -0.89) and LV peak -dP/dt (r=0.87). The LV Tei index significantly increased in dogs with MR compared with normal dogs and significantly increased with progressively more severe clinical signs due to heart failure. The elevation of the LV Tei index in dogs with symptomatic MR appears to be associated with shortening of ejection time. The LV Tei index significantly increased with age and was not correlated with heart rate and body weight in normal dogs. In conclusion, our study demonstrated that the LV Tei index was measurable in dogs and not influenced by heart rate and body weight. The LV Tei index significantly increased with the progression of clinical signs in MR dogs. In particular, the elevation of the LV Tei index in dogs with symptomatic MR due to shortening of ejection time may suggest LV systolic dysfunction and the decrement of forward stroke volume.     

Extension of the culture period for the in vitro growth of bovine oocytes in the presence of bone morphogenetic protein‐4 increases oocyte diameter,but impairs subsequent developmental competence

Bone morphogenetic protein‐4 (BMP‐4) inhibits luteinization of granulosa cells during in vitro growth (IVG) culture of bovine oocytes; however, oocytes derived from a 12 day IVG were less competent for development than in vivo‐grown oocytes. We herein investigated whether an extended IVG culture with BMP‐4 improves oocyte growth and development to blastocysts after in vitro fertilization. Oocyte‐granulosa cell complexes (OGCs) were cultured for 14 or 16 days with BMP‐4 (10 ng/mL), while a 12 day culture with BMP‐4 served as the in vitro control. OGC viability was maintained for the 16 day culture with BMP‐4 (83.2%), but was significantly lower without BMP‐4 (58.9%) than the control (83.0%). Prolong‐cultured oocytes at 16 days had statistically greater diameter (114.6 μm) than the control (111.7 μm). IVG oocytes with BMP‐4 for the 16 day culture had a similar nuclear maturation rate to the control (approximately 67%); however, blastocyst rates in BMP‐4 treated oocytes of 14 (1.8%) and 16 day (0%) IVG were statistically lower than that of 12 day IVG (9.0%). In conclusion, BMP‐4 maintained OGC viability and promoted oocyte growth in a prolonged culture, but impaired the developmental competence of oocytes. Prolonged culture may not be an appropriate strategy for enhancing the developmental competence of IVG oocytes.     

Using angling and electric fishing to estimate smallmouth bass abundance in a river

Estimating abundance is fundamental to effective fishery management but can be challenging in a river where spatial and temporal heterogeneity may preclude the consistent use of a single sampling gear and different gears have differing size selectivity and capture probabilities of fish. In this study, the number of smallmouth bass, Micropterus dolomieu Lacepède, was estimated based on mark–recapture data from angling and boat electric fishing in a 4.2‐km regulated section (mean width = 115 m) of the Broad River, South Carolina, USA. Closed‐population capture–mark–recapture models were fit in the Bayesian hierarchical modelling framework with an estimated number of 2,380 fish (95% credible interval: 1,578–3,693) over 200 mm TL, although simulations indicated that abundance would be slightly overestimated (<20%) when two gears selected for different individuals. Integrating two gear types into a mark–recapture study can provide a method for assessing abundance in spatially or temporally heterogeneous habitats.     

Effects of cultivation of preceding plants on the development of Fusarium wilt of cucumber and daikon

The effects of the cultivation of preceding plants on the inhibition of Fusarium wilts, vessel diseases of cucumber (Cucumis sativus) caused by Fusarium oxysporum f. sp. cucumerinum (FOC) and yellows of daikon (Raphanus sativus var. longipinnatus) caused by F. oxysporum f. sp. raphani (FOR), were examined. When the cucumber or daikon plant was cultivated as a succeeding plant in the pots where the soils had been inoculated with a spore suspension of FOe or FOR and then various preceding plants had been cultivated, the percentage of disease of the succeeding plants was lower in some plots than in the control plot without preceding plants. Spinach (Spinacia oleracea, cv. Atlas) and burdock (Arctium lappa, cv. Takinogawa) inhibited significantly the vessel disease caused by FOe. Thrnip (Brassica rapa, Parental Line Nou No.1) and spinach (S. oleracea, cv. Try) suppressed the yellows caused by FOR. When the number of FOC or FOR was estimated by the recovery using Komada med.ium and by testing their pathogenicity to the host plant, cucumber or daikon, the numbers of both were not reduced in the plots even where these plants had been cultivated initially. The soil extract from the pots, where preceding plants had been cultivated, did not affect the conidia of FOC and FOR. In both FOC and FOR experiments, the cultivation of preceding plants increased the number of bacteria in soil. Additionally, in the FOR experiment, preceding plants, turnip and spinach, increased the number of F. oxysporum (FOX) except for FOR and decreased the proportion of FOR to FOX. It was suggested that these preceding plants might affect the pathogens of Fusarium wilt indirectly by the changes in the numbers and flora of soil microorganisms.     

A method for sex identification in asparagus using DNA from seeds

Asparagus (Asparagus officinalis L.) is a dioecious species, with both male and female individuals. Male plants are more desirable to cultivate than female plants because they have higher yields, and, unlike female plants, they do not have a weed problem resulting from fallen seeds. A male-specific DNA marker is currently available to identify the sex of asparagus individuals using total DNA extracted from cladodes and roots. However, no published method is currently available for DNA extraction and PCR amplification from asparagus seeds. In this study, we tested several heat-resistant DNA polymerases for PCR and several methods for extracting DNA from asparagus seeds and successfully established a method for identifying the sex of asparagus seeds using this male-specific DNA marker. We found that PCR amplification of DNA extracted from asparagus seeds using simple methods such as single-step DNA extraction requires the use of high efficiency DNA polymerase. By contrast, many types of heat-resistant DNA polymerases can be used for PCR amplification of high-quality DNA extracted from asparagus seeds using a commercially available DNA extraction kit. Our method for sex identification of asparagus seeds could facilitate quality checking of all-male asparagus seeds and accelerate the screening of super-male asparagus.     

Obtaining an Ogura-type CMS line from asymmetrical protoplast fusion between cabbage (fertile) and radish (fertile)

Cytoplasmic male sterile (CMS) plants were obtained by asymmetrical protoplast fusion between red cabbage (fertile) and normal radish (fertile). The CMS plants showed restriction fragment length polymorphism (RFLP) patterns of mitochondrial (mt) DNA that were different from those of both parental lines. PCR analysis of mtDNA of the CMS plants and though Southern blot analysis showed that the mtDNA of the CMS line had the characteristics of the ogura CMS type. The results suggested that the orf138 gene and the ogura type atp6 gene are present in normal fertile cabbage and radish at a low copy level. This revised version was published online in July 2006 with corrections to the Cover Date.     

Histopathology of incidental findings in cynomolgus monkeys ( macaca fascicularis ) used in toxicity studies

The purpose of our publication is to widely communicate pictures of spontaneous findings occurring in cynomolgus monkeys. Focal lymphoplasmacytic infiltration is commonly seen in the general organs. The frequency and severity of these lesions may be influenced by the administration of drugs with an effect on the immune system. Lymphoplasmacytic infiltration in the lamina propria of the stomach is also frequently seen in cynomolgus monkeys, and it is caused mainly by a Helicobacter pylori infection. Various degrees of brown pigments are observed in various organs, and it is possible to distinguish the material of the pigments by its morphological features and site. A focal/segmental glomerular lesion is occasionally seen in a section of the kidney, and the minimal lesion has no influence on the urinalysis. We showed the common glomerular lesions in HE-stained sections, as well as in PAM- or PAS-stained sections, for understanding the details. Young and pubertal monkeys are usually used in toxicity studies; therefore, understanding various maturation stages of the genital system is important. In particular, the female genital system needs to be understood in the morphology, because their cyclic changes are different from other laboratory animals. Thus, we present the normal features of the cyclic changes of the female genital organs. Furthermore, we provide more information on spontaneous findings in cynomolgus monkeys for exact diagnoses in toxicity studies.