Influence of ventral fixation techniques on atlantoaxial joint fusion in canine models with dens partial resection

We evaluated the completeness of bony fusion of the atlantoaxial joint (AAJ) through polymethylmethacrylate fixation (PMF) and atlantoaxial plate fixation (APF) using six canine models with dens partial resection. In both groups, the hydroxyapatite content at the AAJ was measured up to 7 months postoperatively using quantitative computed tomography. Histological assessment revealed fibrous fusion in the PMF group. Meanwhile, in the APF group, only one dog achieved fibrous fusion, whereas the remaining three showed bony fusion. To our knowledge, this study was the first to evaluate AAJ fusion histologically after PMF and APF. The present study demonstrates that PMF and APF may stabilize the AAJ without clinical complications. Therefore, PMF and APF are clinically useful fixation methods for atlantoaxial instability.     

Effects of feeding and animal performance on nitrogen, phosphorus and potassium excretion by Holstein cows

Thirty‐four Holstein dry cows and 16 lactating cows were used in balance trials to identify the effects of feeding and animal performance on nitrogen (N), phosphorus (P) and potassium (K) excretion by dairy cows, and to develop prediction models for these excreta. Orchard grass silage, corn silage, alfalfa silage or timothy hay were offered to dry cows. Orchard grass silage or alfalfa silage, and concentrates were offered to lactating cows. In the statistical analysis, the independent variables were bodyweight (kg), dry matter (DM) intake (kg/day), milk yield (for lactating cows only, kg/day), water intake (free water plus water in feed, kg/day), intake (g/day) of N, P and K and dietary contents (% of DM) of crude protein, P and K. The dependent variables were N, P and K excretion (g/day) in feces and urine. In both dry and lactating cows, intake of N, P and K had large effects on corresponding excretion. The results indicated that a decrease in the intake of N, P and K could decrease the corresponding excretion. Further research by path analysis showed that K intake positively affected urinary N excretion in dry cows indirectly, through water intake and urine volume.     

Effect of Addition of Al Hydroxides on Changes in Dispersibility and Charge Characteristics of Soils

Using a soil from a newly reclaimed area where high dispersibility of fine particles had led to poor physical properties in the field, changes in dispersibility and charge characteristics after artificial precipitation of Al hydroxides onto the soil were investigated. Al hydroxides were precipitated by neutralization with NaOH of an acidic A1C1₃ solution in which the soil samples were placed.

When the titration rates were changed, no significant differences in dispersibility were observed in the resultant soils. In the systems with the addition of 2 g kg^-1 or less of A1(OH)₃, dispersion ratios of clays were almost identical with those of blank samples although the specific surface areas were reduced. In the systems with 5 g kg^-1 or more of A1(OH)₃, considerable effects of Al hydroxides on reduction of clay dispersibility were recognized (e.g. 10 g kg^-1 addition yielded less than one-third of the original ratio of the clay dispersion). A slightly larger decrease in dispersion was observed by the addition of 15 g kg^-1 or more. As the amount of added Al increased, the amount of negative charges of the soil decreased while that of positive charges increased. The charge characteristics of the system with the addition of 20 g kg^-1 of A1(OH)₃ were closer to those of the adjacent forest soil which was characterized by a very low dispersibility. It was inferred that added Al hydroxides polymerized to form Al polycation species that were not readily exchangeable, neutralizing negative charges of clays, and acting as interparticle bonding between the clays. On the other hand, forest soils were considered to have acquired a physical stability against the dispersion of fine particles as free Al oxides had been accumulated in the process of natural weathering. It was concluded that charge characteristics primarily determined the dispersion and flocculation behavior of soils and that Al hydroxides were important modifiers of charge characteristics of soils.     

Evaluation of relationship between dispersibility of soils and charge characteristics using a modified ion adsorption method; An example of soils from Wakayama Prefecture,Japan

The relationship between the charge characteristics and the dispersibility of soils from reclaimed land (highly dispersive) and adjacent forest area (physically stable) was investigated.

To evaluate the amount of soil charges quantitatively, the measurement based on cation and anion adsorption (ion adsorption method) was attempted in two ways, where special attention was paid to the solution concentration. In the conventional ion adsorption method, the treatments with concentrated solutions (1 mol L^-1) were included in the process. In the modified method, soils were treated with dilute solutions (5 mmol L^-1), in taking account of the soil solution concentration in humid temperate regions. The amount of charges derived from the modified method was smaller than that from the conventional one, especially in the high pH zone. In a preliminary experiment, the extraction of polyvalent cations from soils was found to be significantly affected by the salt concentration. Thus, the use of solutions with an excessively high concentration was considered to result in an error in the estimation of the active charges in soils which would contribute to the dispersion behavior in the field.

The applicability of the modified method for analyzing the dispersion behavior of soils was evaluated by relating the dispersibility of silts and clays at different pHs with the charge characteristics determined under the same ionic strength. The dispersion ratio of silts of the reclaimed land reached maximum values at pH 5.5, above which the ratio decreased, whereas the ratio of clays began to increase in the pH range above 6. The dispersion ratio of silts of the forest area increased in the pH range above 6, whereas that of clays remained constant at a low level in all the pH ranges below 7. The changes in the dispersibility of silt plus clay fractions corresponded to total charge characteristics determined by the modified method. Thus, the evaluation of soil charges by the modified ion adsorption method was considered to be effective to predict soil dispersibility under field conditions, indicating that it could replace electrokinetic analyses such as electrophoresis in studies on the dispersion/flocculation behavior of soils.     

Use of Jeffries acid oxalate treatment in particle-size analyses of Ando soils

Use of Jeffries acid-oxalate treatment in particle-size analyses of Ando soils for breaking up the sand- and silt-size aggregates bound by allophane, allophane-like constituents and hydrous iron oxides was studied. The analyses by this method and those by a method using sonic-wave oscillation were compared for nine Ando soil samples having different clay-mineral compositions and organic-matter contents. There were minor differences in the sand contents between the two analyses, but the clay contents were higher and the silt contents were lower after Jeffries acid oxalate treatment.

Characterization of the silt-size separates by an X-ray powder method, water vapor adsorption and electron microscopy indicated that the lower silt contents after Jeffries acid oxalate treatment were mainly due to dissolution of allophane and allophane-like constituents, whereas the silt-size separates after sonic-wave treatment still contained these mineral constituents. The proposed procedure for particle-size analysis was also useful for two ferruginous soils representing the Hydrandept and Torrox.     

Epidemiological study on <Emphasis Type="Italic">Lactococcus garvieae</Emphasis> isolates from fish in Japan

In Japan, Lactococcus garvieae infection has been the main fish disease in aquaculture. Although commercial oral and injectable vaccines have been used to prevent L. garvieae infection in Japan, L. garvieae has been isolated not only from unvaccinated fish but also from vaccinated fish in which immunity induced by vaccination had diminished. In order to obtain epidemiological information on this fish pathogen, we conducted biased sinusoidal field gel electrophoresis (BSFGE) pattern analysis and phage typing of L. garvieae isolates (n = 427) from fish in Japan. These isolates were obtained from 13 different fish species between 1980 and 2007. In the BSFGE analysis, L. garvieae isolates were classified into 17 groups (S1–S17) based on the SmaI digestion patterns and into four groups (A1–A4) based on the ApaI digestion patterns. Phage typing revealed five different phage susceptibility profiles (A–E) in L. garvieae isolates. Since 2005, comparisons of the results of phage typing and BSFGE have indicated the presence of a novel genotype (S16/A4) with phage type E. All the strains belonging to this type showed lincomycin sensitivity.     

Quantitative loop-mediated isothermal amplification method for the detection of <Emphasis Type="Italic">Vibrio nigripulchritudo</Emphasis> in shrimp

Vibrio nigripulchritudo is considered one of the major pathogens threatening shrimp aquaculture. In this study, we developed a novel and highly specific quantitative loop-mediated isothermal amplification (Q-LAMP) assay. A set of four specific primers were designed targeting the V. nigripulchritudo intergenic spacer region. The reaction time and temperature were optimized for 60 min at 63°C. Quantitative analysis was then performed by measuring the turbidity of the reaction solution using a real-time turbidimeter, allowing for quantification of the initial DNA concentration with a sensitivity of 10² copy numbers equivalent to 2.3 colony forming units/ml or 0.3 fg/μl. The LAMP assay was able to specifically detect two representative strains of V. nigripulchritudo, whereas other Vibrio and non-Vibrio species were not amplified. A standard curve was generated for V. nigripulchritudo by plotting the threshold time (T _t) versus the log of bacterial number. A high correlation coefficient (R ² = 0.9749) was observed for the Q-LAMP reaction. In conclusion, Q-LAMP assay is a sensitive, rapid, and simple tool that can be used for the detection and quantification of V. nigripulchritudo in shrimp, thereby facilitating surveillance of vibriosis infection.     

Cloning and expression of a surface immunogenic protein in Streptococcus dysgalactiae isolated from fish and its application in enzyme‐linked immunosorbent assays to diagnose S. dysgalactiae infections in fish

Lancefield group C Streptococcus dysgalactiae (GCSD) causes severe necrotic lesions in the caudal peduncle in the genus Seriola farmed in Japan. To develop a sero‐diagnostic method for GCSD infection in farmed fish, we attempted to identify a surface immunogenic protein that induces an antibody after infection with GCSD by immunoblot analysis using sera collected from infected fish. A protein obtained from sodium dodecyl sulfate (SDS) extracts of GCSD was identified as S. dysgalactiae surface immunogenic protein (Sd‐Sip). Sd‐Sip exhibited more than 94% homology with a surface antigen or a hypothetical protein from S. dysgalactiae mammalian isolates at the nucleotide sequence level. Expression of the recombinant Sd‐Sip (rSd‐Sip) was confirmed by immunoblot analysis, that is, its reactivity to GCSD‐infected sera. Antibody detection ELISA using rSd‐Sip and their usefulness for diagnosis of GCSD infection were examined. GCSD‐infected sera collected from farmed amberjack, Seriola dumerili (Risso), showed strong reaction with immobilized rSd‐Sip. Meanwhile, sera immunized by other pathogenic bacteria of fish were showed ELISA values similar to those of non‐infected sera. These results of this study suggest that the antibody detection ELISA using rSd‐Sip is an effective diagnostic method for GCSD infection in fish.