Effects of long-term administration of recombinant bovine tumor necrosis factor-alpha on glucose metabolism and growth hormone secretion in steers

OBJECTIVE: To investigate the effects of long-term administration of recombinant bovine tumor necrosis factor-alpha (rbTNF) on plasma glucose and growth hormone concentrations, and to determine whether treatment with rbTNF causes insulin resistance in steers. ANIMALS: 5 steers treated with rbTNF and 5 steers treated with saline (0.9% NaCl) solution (control). PROCEDURES: In experiment 1, rbTNF (5.0 microg/kg of body weight) or saline solution (5 ml) was administered SC daily for 12 days. Blood samples were obtained before treatment, and plasma was harvested for determination of glucose, insulin, and growth hormone (GH) concentrations. In experiment 2, insulin, glucose, or growth hormone-releasing hormone (GHRH) was administered IV on days 7, 9, and 11, respectively, after initiation of rbTNF or saline treatment in experiment 1. Plasma glucose and insulin concentrations were measured before and at various times for 4 hours after insulin or glucose administration. Plasma GH concentrations were measured at various times for 3 hours after GHRH administration. RESULTS: In experiment 1, administration of rbTNF resulted in hyperinsulinemia without hypoglycemia and decreased plasma GH concentrations. In experiment 2, plasma glucose concentrations were higher in steers treated with rbTNF and insulin than in controls. Plasma GH concentrations were lower in steers treated with rbTNF and GHRH than in controls. CONCLUSIONS AND CLINICAL RELEVANCE: Prolonged treatment with rbTNF induced insulin resistance and inhibited GHRH-stimulated release of GH in steers. Results indicate that rbTNF is a proximal mediator of insulin resistance and inhibits release of GH during periods of endotoxemia or infection.     

Comparison of adjuvants with respect to serum IgG antibody response in orally immunized chickens

We have previously shown that oral immunization with non-replicating antigens hardly induced serum IgG antibody response in chickens and addition of sodium fluoride (NaF) to the immunogen markedly improved their immunological states. In the present study, taurine, lithium and Quillaja saponin (Q-SAP) were compared with NaF with respect to their enhancement of serum IgG antibody response in chickens after oral immunization. The antibody titer of chickens which received Q-SAP as the mucosal adjuvant tended to be higher than that of chickens which received antigen plus NaF. Simultaneous administration of antigen with lithium or taurine elicited a higher antibody titer in chickens compared to those of chickens orally immunized with antigen alone, but the effect of these two adjuvants was less efficient compared with that of NaF. These results suggested that Q-SAP as well as NaF is useful as an oral adjuvant for chickens.     

Localization of cytokines in tendinocytes of the superficial digital flexor tendon in the horse

Although inflammatory activation of cytokines have been analyzed in various tissues, there have only been a few and as-yet-inconclusive studies on cytokines in equine tendons. In this study, the localizations of 4 cytokines (IL-1alpha, IL-1beta, TNFalpha and IFNgamma) in tendinocytes of the equine superficial digital flexor tendon (SDFT) were analyzed by the use of an immunohistochemical method. In inflamed tendons positive staining for all 4 cytokines antibodies were detected in endotedinieum cells and vascular epithelial cells. In contrast, negative or trace immunoreactions were obtained in many tendinocytes in the normal tendon. The variation in cellular immune responses depending on the kind of cytokine may reflect the physiological/pathological condition of the SDFT.     

Cardiovascular effects of medetomidine, detomidine and xylazine in horses

The cardiovascular effects of medetomidine, detomidine, and xylazine in horses were studied. Fifteen horses, whose right carotid arteries had previously been surgically raised to a subcutaneous position during general anesthesia were used. Five horses each were given the following 8 treatments: an intravenous injection of 4 doses of medetomidine (3, 5, 7.5, and 10 microg/kg), 3 doses of detomidine (10, 20, and 40 microg/kg), and one dose of xylazine (1 mg/kg). Heart rate decreased, but not statistically significant. Atrio-ventricular block was observed following all treatments and prolonged with detomidine. Cardiac index (CI) and stroke volume (SV) were decreased with all treatments. The CI decreased to about 50% of baseline values for 5 min after 7.5 and 10 microg/kg medetomidine and 1 mg/kg xylazine, for 20 min after 20 microg/kg detomidine, and for 50 min after 40 microg/kg detomidine. All treatments produced an initial hypertension within 2 min of drug administration followed by a significant decrease in arterial blood pressure (ABP) in horses administered 3 to 7.5 microg/kg medetomidine and 1 mg/kg xylazine. Hypertension was significantly prolonged in 20 and 40 microg/kg detomidine. The hypotensive phase was not observed in 10 microg/kg medetomidine or detomidine. The changes in ABP were associated with an increase in peripheral vascular resistance. Respiratory rate was decreased for 40 to 120 min in 5, 7.5, and 10 microg/kg medetomidine and detomidine. The partial pressure of arterial oxygen decreased significantly in 10 microg/kg medetomidine and detomidine, while the partial pressure of arterial carbon dioxide did not change significantly. Medetomidine induced dose-dependent cardiovascular depression similar to detomidine. The cardiovascular effects of medetomidine and xylazine were not as prolonged as that of detomidine. KEY WORDS: cardiovascular effect, detomidine, equine, medetomidine, xylazine.     

Production of transgenic rabbits using centrifuged pronuclear zygotes

Superovulation of female rabbits was induced by subcutaneous injection(s) of porcine FSH. Zygotes were recovered 17 to 19 hr after hCG injection and were classified into two categories under a microscope equipped with Nomarski interference-contrast optics at x 200 magnification: (A) zygotes with clearly visible pronuclei, or (B) zygotes with visualized pronuclei after 10 min centrifugation at 12,000 x g. No significant difference between strains was found in the proportion of category-A zygotes (JW 72.6% vs NZW 79.3%). Pronuclei of category-A zygotes were located in the center of the cytoplasm, and the pronuclei of category-B zygotes were slightly moved by centrifugation toward the mass of cytoplasmic lipid droplets. Exogenous DNA solution (5 microg/ml of fusion gene composed of bovine alphaS1-casein promoter and human growth hormone structural gene) was microinjected into the pronucleus of the JW zygotes. The pronucleus of category-A zygotes with a mean volume of 7.4 pl swelled up to 16.6 pl (132% increase), while that of category-B zygotes with a mean volume of 6.1 pl swelled up to 15.9 pl (148% increase). Nevertheless, similar proportions of category-A and category-B zygotes developed into offspring after transfer to recipient females (11.1 and 11.2%, respectively). The efficiency to produce hGH-carrying transgenic rabbits was 0.9% (2/235) from category-A zygotes and 0.5% (1/215) from category-B zygotes (P>0.05). To date, transgenic rabbits have been produced without centrifugation of pronuclear zygotes. However approximately 25% of fertilized rabbit zygotes can be used for DNA microinjection after they have been centrifuged to visualize their pronuclei.     

First report of the Q biotype ofBemisia tabaci in Japan by mitochondrial cytochrome oxidase I sequence analysis

The recent upsurgence ofBemisia tabaci (Genn.) as an important insect pest and vector ofTomato yellow leaf curl virus (TYLCV) is directly linked to serious damage to tomato crops grown throughout Japan. The molecular genetic identification and phylogenetic relationships of 12B. tabaci populations collected from representative locations in Japan were determined based on the mitochondrial cytochrome oxidase I (mtCOI) sequence. Phylogenetic analysis of the whitefly mtCOI sequence indicated that both the invasive B and Q biotypes now occur in Japan. The Q biotype was found at four locations: Mihara in Hiroshima, Nishigoshi in Kumamoto, Miyanojo and Okuchi in Kagoshima prefectures; the remaining eight collections were identified as the B biotype. This is the first report of the introduction of Q biotype in Japan. http://www.phytoparasitica.org posting July 21, 2006.     

Identification of Petunia hybrida cultivars that diurnally emit floral fragrances

In order to identify genetic resources for breeding fragrant petunias for use as bedding plants, volatile compounds released by day from the flowers of 40 commercial Petunia hybrida cultivars were analyzed using a solid-phase micro-extraction technique coupled with GC–MS. The three cultivars with solid deep-blue flowers that accumulate malvidin in corollas with high tissue pH were found to emit abundant iso-eugenol as the principal floral fragrance. Several other cultivars that emitted considerable amounts of methylbenzoate and/or benzylbenzoate from the flower were also identified. Association between the floral fragrance and the other floral traits such as floral anthocyanin composition and corolla-tissue pH was discussed.     

Effect of ethephon (2-chloroethylphosphonic acid) on the fruit ripening characters of rabbiteye blueberry

Effect of ethephon (2-chloroethylphosphonic acid) application on rabbiteye blueberry fruit quality during the growth period was investigated. Ethephon treatment stimulated the decrement of titratable acidity, anthocyanin accumulation and fruit softening 4 days after treatment and the promoting effects continued through the investigation period. The ripening promotion effect of ethephon on total soluble solids content was observed only 8 days after treatment. Ethephon treatment did not affect the fruit enlargement during the investigation period. From these results, it is concluded that ethephon application for rabbiteye blueberry promote the fruit ripening, but the stimulatory effects of ethephon on fruit ripening were different in degree on each ripening characters.