An experimental study of apico-aortic valved conduit (AAVC) for surgical treatment of aortic stenosis in dogs

A new valved conduit was developed using a canine aortic valve. The bioprosthetic valve was fixed with glutaraldehyde and epoxy compound (Denacol-EX313/810). A vascular graft composed of ultra-fine polyester fiber (10 mm in diameter, 200 mm in length) was used. Four dogs underwent apico-aortic valved conduit (AAVC) implantation and aortic banding (bypass group, BG), while another 4 dogs underwent aortic banding without AAVC implantation (control group, CG). Cardiac catheterization and angiocardiography were performed for assessment of hemodynamics 2 weeks and 6 months after surgery. Left ventricular systolic pressure, left ventricular end-diastolic pressure and the left ventricular-aortic pressure gradient differed significantly (P<0.01) between the BG and CG dogs. Left ventricular angiocardiography showed patency of the valved conduit in all the BG dogs. Echocardiography was performed before and 2, 4 and 6 months after surgery, and showed that while pressure overload caused concentric myocardial hypertrophy in the CG dogs, the left ventricle dilated eccentrically in the BG dogs. Furthermore, relief of left ventricular pressure overload by AAVC was maintained.     

Validation of the bovine blood calcium checker as a rapid and simple measuring tool for the ionized calcium concentration in cattle

Point-of-care (POC) devices that veterinary practitioners can use to easily and rapidly measure blood ionized calcium (iCa) levels in cows immediately after withdrawing a blood sample on the dairy farm are needed. Aims of present studies was to compare the commercially available ion-selective electrode handheld iCa meter (bovine blood iCa checker) with the benchtop blood gas analyzer GEM premier 3500 and handheld analyzer i-STAT 1. Sixty-two paired-point whole blood samples were obtained from three cows with hypocalcemia experimentally induced by Na₂-EDTA infusion. Whole blood samples were also obtained from the 36 cows kept on a farm in field conditions. The results using the bovine blood iCa checker correlated with those using the GEM premier 3500 and i-STAT 1. Bovine blood iCa checker was “compatible” with the GEM premier 3500 and i-STAT 1 because the frequency of differences between the measurements within ± 20% of the mean were 100% (65/65, >75%) and 90.8% (59/65, >75%), respectively. In the field trial, the blood iCa concentration measured by the bovine blood Ca checker was significantly positively correlated with that measured by the i-STAT 1 portable analyzer. Bovine blood iCa checker was “compatible” with the i-STAT 1 because the frequency of differences between the measurements within ± 20% of the mean was 100% (36/36, >75%). Results from these findings, the bovine blood iCa checker may be applied as a simplified system to measure the iCa concentration in bovine whole blood.     

Effects of night‐time light intensity on the survival rate and stress responses in juvenile Pacific bluefin tuna Thunnus orientalis (Temminck and Schlegel)

Land‐based cultured juvenile Pacific bluefin tuna Thunnus orientalis (PBT) have high mortality rates due to collisions or contacts with tank walls after about 30 days of hatching. To determine the effect of night‐time lighting on their survival, juvenile PBT were reared under four different night‐time light intensities (0, 5, 15 and 150 lx) for 9 days, followed by a 3‐day observation period. High‐intensity, night‐time lighting (150 lx) significantly improved the survival rate (75.8%; P < 0.001) compared with the unlit control group (0 lx, 64.3%). The survival rate in the high‐intensity group decreased after the end of the lighting period. Lighting did not influence whole‐body cortisol levels, glucose levels, or diel changes in plasma cortisol levels. In contrast, the survival rates of fish exposed to light intensities between 5 and 15 lx were slightly lower than that of the unlit control group. These results suggest that providing night‐time lighting of 150 lx or higher is an effective method for reducing the mortality of cultured PBT.     

Relatedness structure estimated by microsatellites DNA and mitochondrial DNA polymerase chain reaction–restriction fragment length polymorphisms analyses in the wild population of kuruma prawn Penaeus japonicus

ABSTRACT: The genetic structure and variability of four wild populations of kuruma prawn in Japan were examined by estimating relatedness among individuals. The relatedness was estimated by five microsatellites (MS) DNA markers. Examination of relatedness showed that individuals were related significantly in Kumamoto and Kagoshima. In Kagoshima, some individuals showed full-sib level of relatedness. The analysis of mitochondrial (mt)DNA polymerase chain reaction–restriction fragment length polymorphisms (PCR-RFLP) was also performed, showing that the closely related individuals in Kagoshima tended to share a common haplotype. It is, therefore, supposed that there are many kins in Kumamoto and Kagoshima. However, the heterozygosities and allelic and genotypic frequencies in MS-DNA analysis were not significantly different among the localities. Moreover, the haplotype distributions of mtDNA in Kumamoto and Kagoshima were significantly different from other localities. Thus, it is suggested that no spatial differentiations occurred due to the geographic or historical effects between the localities and that there is the possibility of a mixture of hatchery populations in Kumamoto and Kagoshima.     

Investigation into the durability of washed rice straw for equine bedding and the repetitive use of washing water

The present experiment investigated durability during the repetitive use of washed rice straw, as bedding material, and washing water as a model study. Residual nitrogen levels, elasticity, and water suction rates for washed rice straw‐adhered urea were measured. In addition, outflow levels of nitrogen and mineral ions (Na⁺, NO₂^‐ + NO₃^‐, SO₄^2?, PO₄^3?, Cl^‐) for washing water were measured to determine durability. Nitrogen levels of rice straw significantly (P < 0.05) decreased after two washings. There was no significant change in elasticity of repetitively used rice straw. Suction rates of rice straw after the second and third washings increased significantly (P < 0.05) compared to the first time. With regard to the number of washings, the mineral ion outflow level in the washing water for nitrogen, Na⁺, NO₂^‐ + NO₃^‐ and PO₄^3? after each washing was not significant. However, nitrogen outflow level tended to decrease after the third washing. SO₄^‐ and Cl^‐ did significantly decrease (P < 0.05) with the number of washings. In this study, it was considered that rice straw and washing water could be used repetitively three times. Furthermore, in order to maintain effluent standards, washing water from the first washing needs to be processed in a septic tank.     

Promoter analysis of two aromatase genes in the serial-sex changing gobiid fish, Trimma okinawae

Despite numerous endocrine studies on sex change in teleost, no general mechanism that mediates sex change has emerged. The gobiid fish, Trimma okinawae, can change sex in both directions repeatedly. This phenomenon of sex change in goby assigns it as an excellent animal model to elucidate the understanding mechanisms of sex change. In hermaphrodite fishes, estrogen plays a particularly important role in natural and experimentally induced sex change. To investigate the role of estrogen in the serial-sex changing fish T. okinawae, we cloned and analyzed the 5′-flanking regions of P450arom genes from goby genome DNA. Both regions have consensus sequences of TATA, CRE and ERE. Ad4 binding site was restricted in the region of P450aromA. These findings indicate that different regulators control the expression of the two P450arom genes.     

Effects of bisphenol A administration to pregnant mice on serum Ca and intestinal Ca absorption

Bisphenol A (BPA) is a xenoestrogen commonly used in food storage plastics. The present study was conducted to clarify the effects of BPA administration to pregnant mice on serum calcium (Ca) and Ca metabolism of the gut and kidney. From 6.5 to 16.5 days post coitus (dpc), pregnant mice were administered at 2 mg or 20 mg/kg body weight/day of BPA. Serum Ca was decreased in mice treated with 20 mg BPA at 17.5 dpc, but no remarkable differences were detected in the alkaline phosphatase activity and vitamin D receptor protein expression in the duodenum and jejunum. The messenger RNA (mRNA) expressions of calcium binding protein (CaBP‐9k) and active vitamin D synthesis enzyme (CYP27B1) in the kidney were increased in mice treated with 20 mg BPA. The mRNA expressions of occludin and junction adherence molecular A (JAM‐A) in the duodenum and ileum, which regulate paracellular transport, were increased in mice treated with 20 mg BPA. However, the administration of 2 mg BPA had no effect on serum Ca and mRNA expressions of relative genes in Ca metabolism. These results imply that BPA administration at 20 mg/kg body weight/day during pregnancy decreases serum Ca in pre‐delivery mice, which may be partly due to decreased paracellular Ca absorption.     

Timing to promote initial swimbladder inflation by surface film removal in Pacific bluefin tuna,Thunnus orientalis (Temminck and Schlegel), larvae

This study investigated the optimal timing of day to promote initial swimbladder inflation (ISI) for improved Pacific bluefin tuna (PBT), Thunnus orientalis, larval survival. Larval swimbladder inflation frequency was compared based on three experiments using different time schemes of surface film removal (SFR) from 3 to 9 days post hatch (dph). SFR was conducted from 05:00 to 19:00 hours (light period: S.5–19), 19:00 to 05:00 hours (dark period: S.19–5), 08:00 to 19:00 hours (S.8–19) and the entire day (S.24) in Experiment 1; from 08:00 to 19:00 hours (S.8–19‐E2), 08:00 to 13:00 hours (S.8–13), 13:00 to 19:00 hours (S.13–19) in Experiment 2; and from 13:00 to 16:00 hours (S.13–16), 16:00 to 19:00 hours (S.16–19), 18:00–19:00 hours (S.18–19) in Experiment 3. The swimbladder inflation frequency at the experiment termination (9 dph) was significantly higher (P < 0.001) in S.24 (91.1 ± 5.7%), S.5–19 (92.2 ± 5.1%) and S.8–19 (93.3 ± 3.4%) than in S.19–5 (11.1 ± 5.1%) in Experiment 1, and remarkably higher in S.8–19‐E2 (81.7%) and S.13–19 (88.3%) than in S.8–13 (0.0%) in Experiment 2, and significantly higher (P < 0.001) in S.16–19 (84.4 ± 5.1%) and S.18–19 (70.0 ± 12.0%) than in S.13–16 (7.8 ± 3.9%) in Experiment 3. These results suggest that the optimal timing to promote larval ISI by SFR is a few hours before the end of light period (16:00–19:00 hours) from 3 to 9 dph.