Antagonism of medetomidine sedation by atipamezole in pigs.

The efficacy of atipamezole as a medetomidine antagonist was evaluated in pigs. The atipamezole doses (intramuscularly) were 80, 160, 320 and 480 micrograms/kg of body weight, which were one, two, four and six times higher than the preceding medetomidine dose (80 micrograms/kg, intramuscularly). Atipamezole effectively reversed medetomidine-induced sedation, and the optimal action was seen at doses of 160 and 320 micrograms/kg. Recovery from sedation was quick and smooth, and adverse effects such as hyperactivity or tachycardia were minimal with either dose.     

Dietary mannitol increased the absorption of calcium and magnesium in rats

The effect of mannitol on bone‐related mineral absorption and retention and the mechanism was investigated in this study. Fourteen 8‐week‐old male Wistar rats in experiment 1 and same number and age cecectomized Wistar male rats in experiment 2 were divided into two subgroups of seven animals, respectively, fed diets containing 0 or 4% mannitol for 28 days. Mineral balance tests were determined twice during days 8–12 and days 22–26, and the rats were slaughtered on day 28 both in experiment 1 and experiment 2. The whole caecum and colon were collected with the content to analyse tissue weight, content weight, content's pH and moisture, organic acids' concentration and mineral levels. In experiment 1, Ca absorption and retention and Mg absorption were significantly increased by mannitol feeding during days 8–12. Caecal total weight, tissue weight and content weight were increased, the pH of caecum and colon was reduced, and the concentrations of caecal short‐chain fatty acids (SCFAs) were modified by mannitol feeding. In experiment 2, during days 8–12 and days 22–26, Ca absorption and retention were significantly lowered by mannitol feeding in cecectomized rats; however, mannitol feeding decreased Mg absorption during days 8–12, but did not impact Mg retention. Colonic total weight, tissue weight and content weight were significantly increased, and colonic pH was reduced by mannitol feeding. In conclusion, dietary mannitol increased the absorption of Ca and Mg and the caecum markedly contributed to this promoting effect of mannitol.     

Identification of bovine serum albumin as an IgE-reactive beef component in a dog with food hypersensitivity against beef

IgE-reactive beef components were examined by an immunoblot analysis using a serum from a dog with food hypersensitivity against beef. The immunoblot analysis revealed a distinct band at approximately 66 kDa and a faint band at approximately 50 kDa. The immunoblot analysis for serum IgE reactivity to bovine serum albumin (BSA) also revealed a positive band at 66 kDa. Serum IgE reactivity to the 66-kDa protein of beef was diminished by pre-incubating the serum sample with BSA. Furthermore, a positive reaction to BSA was detected in intradermal testing in the dog. These results clearly indicated that BSA was an IgE-reactive beef component in the dog with food hypersensitivity against beef.     

Seasonal atopic dermatitis in dogs sensitive to a major allergen of Japanese cedar (Cryptomeria japonica) pollen

Three dogs were examined because of episodes of recurrent pruritic dermatitis in the spring, the season of Japanese cedar (Cryptomeria japonica, CJ) pollination in Japan. The dogs were shown to be sensitive to CJ pollen allergen using intradermal testing and antigen-specific IgE measurement. Fluorometric enzyme-linked immunosorbant assay (ELISA) showed increased concentrations of IgE specific to Cry j 1 and a negative result for Cry j 2 in the three dogs. The concentrations of IgE specific to Cry j 1 during the season of CJ pollination were higher than the concentrations found during the off-season in all the dogs, and the variation in the concentrations correlated with the variation in clinical signs. Peripheral blood mononuclear cells showed apparent proliferative responses to crude CJ pollen antigen and Cry j 1 during CJ pollination season. These findings indicated that Cry j 1 was the major allergen recognized by IgE and lymphocytes and resulted in the development of type I hypersensitivity to CJ pollen allergen in these atopic dogs.     

Microdroplet In Vitro Fertilization Can Reduce the Number of Spermatozoa Necessary for Fertilizing Oocytes

Successful in vitro fertilization (IVF) in mice has been achieved using spermatozoa at concentrations specifically optimized for the experimental conditions, such as species and source of spermatozoa. Although IVF in mice is mostly performed using about 80–500 µl drops, it is expected that the number of spermatozoa used for insemination can be reduced by decreasing the size of the IVF drops. The present study was undertaken to examine the extent to which the number of spermatozoa used for IVF could be reduced by using small droplets (1 µl). We devised the experimental parameters using frozen–thawed spermatozoa from C57BL/6 mice in anticipation of broader applications to other mouse facilities. We found that as few as 5 spermatozoa per droplet could fertilize oocytes (1 or 3 oocytes per droplet), although the fertilization rates were low (13–15%). Practical fertilization rates (> 40%) could be achieved with frozen-thawed C57BL/6J spermatozoa, which are sensitive to cryopreservation, when 20 sperm per droplet were used to inseminate 3 oocytes. Even with spermatozoa from a very poor quality suspension (10% motility), about 25% of oocytes were fertilized. Our calculations indicate that the number of inseminated spermatozoa per oocyte can be reduced to 1/96–1/240 by this method. In two separate embryo transfer experiments, 60% and 47%, respectively, of embryos developed to term. Our microdroplet IVF method may be particularly advantageous when only a limited number of motile spermatozoa are available because of inadequate freezing-thawing or genetic reasons.     

Isolation of chicken taste buds for real‐time Ca2+ imaging

We isolated chicken taste buds and used a real‐time Ca²⁺ imaging technique to investigate the functions of the taste cells. With RT‐PCR, we found that isolated chicken taste bud‐like cell subsets express chicken gustducin messenger RNA. Immunocytochemical techniques revealed that the cell subsets were also immunopositive for chicken gustducin. These results provided strong evidence that the isolated cell subsets contain chicken taste buds. The isolated cell subsets were spindle‐shaped and approximately 61–75 μm wide and 88–98 μm long, and these characteristics are similar to those of sectional chicken taste buds. Using Ca²⁺ imaging, we observed the buds' response to 2 mmol/L quinine hydrochloride (a bitter substance) and their response to a mixture of 25 mmol/L L‐glutamic acid monopotassium salt monohydrate and 1 mmol/L inosine 5′‐monophosphate disodium salt, umami substances. The present study is the first morphological demonstration of isolated chicken taste buds, and our results indicate that the isolated taste buds were intact and functional approaches for examining the taste senses of the chicken using Ca²⁺ imaging can be informative.     

Ubiquitous increase in taurine transporter mRNA in tissues of tilapia (Oreochromis mossambicus) during high-salinity adaptation

We have isolated a cDNA encoding the taurine transporter from a tilapia (Oreochromis mossambicus) gill cDNA library. Transient expression of the cDNA in COS-7 cell indicates that the clone encodes a Na⁺- and Cl^–-dependent and -amino acid-specific taurine transporter. By the transfer of tilapia cultured in freshwater to 70% artificial seawater, plasma osmolality increased by up to 100–135 mOsm/kgH₂O along with the marked increase in the taurine transporter mRNA level in all the tissues examined i.e., kidney, stomach, intestine, gill, eye, liver, fin, muscle and brain. In most tissues, time-dependent change in the taurine transporter mRNA level corresponds to that in plasma osmolality. However, fin showed an acute and muscle showed a delayed increase in taurine transporter mRNA compared to changes in plasma osmolality. The taurine transporter mRNA level in tilapia embryos also increased after transfer from freshwater to 100% artificial seawater. Increase in taurine transporter expression leads to the activation of cellular uptake of taurine from plasma and the accumulation of taurine in the cell. Thus the results in the present study suggest that taurine plays an important role as an osmolyte in the ubiquitous tissues of tilapia during high-salinity adaptation.     

Botulism among penned pheasants and protection by vaccination with C1 toxoid

Fifty to 100 per cent of about 8000 penned pheasants raised on a farm in Hiroshima Prefecture died annually for three years. Deaths were ascribed to type C botulism. Vaccination of four groups of pheasants with partially purified C1 toxoid effectively protected them against type C botulism. The protective efficacy of the toxoid was emphasised by the relatively high susceptibility of the pheasant to C1 toxin.     

Structural unit of xylans from sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) and hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>)

Arabinoglucuronoxylans (AGXs) isolated from the holocellulose of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) contained one 4-O-methyl-d-glucopyranosyluronic acid (4-O-Me-d-GlcAp) residue per 6.2 d-xylopyranose (d-Xylp) residues and one 4-O-Me-d-GlcAp residue per 3.8 d-Xylp residues. These AGXs were subjected to partial acid hydrolysis. Analyses by size exclusion chromatography and electrospray-ionization mass spectroscopy of the neutral sugar fractions in the hydrolysates showed the presence of xylooligosaccharides having a degree of polymerization of 2-8 in addition to d-Xyl, suggesting that the AGXs from sugi and hinoki contained unsubstituted chains consisting of at least eight d-Xyl residues. The acidic sugars in the hydrolysates were separated into two series of aldouronic acids composed of 4-O-Me-d-GlcAp and d-Xylp by ion-exchange chromatography. The first series included aldouronic acids from aldobiouronic acid (4-O-Me-d-GlcAp-Xyl) to aldopentaouronic acids (4-O-Me-d-GlcAp-Xyl₄). The second series were aldouronic acids composed of two 4-O-Me-d-GlcAp residues and 2-4 d-Xyl residues. In these acidic sugars, the uronic acid side chains were located on two contiguous d-Xyl residues. These facts indicated that AGXs from sugi and hinoki had a structural unit containing two 4-O-Me-d-GlcAp residues on two contiguous d-Xyl residues as well as AGXs from spruce and larch.     

Prevention of acute liver failure in rats with reversibly immortalized human hepatocytes

Because of a critical shortage in suitable organs, many patients with terminal liver disease die each year before liver transplantation can be performed. Transplantation of isolated hepatocytes has been proposed for the temporary metabolic support of patients awaiting liver transplantation or spontaneous reversion of their liver disease. A major limitation of this form of therapy is the present inability to isolate an adequate number of transplantable hepatocytes. A highly differentiated cell line, NKNT-3, was generated by retroviral transfer in normal primary adult human hepatocytes of an immortalizing gene that can be subsequently and completely excised by Cre/Lox site-specific recombination. When transplanted into the spleen of rats under transient immunosuppression, reversibly immortalized NKNT-3 cells provided life-saving metabolic support during acute liver failure induced by 90% hepatectomy.