Skeletal muscle characteristics in young trained and untrained standardbred trotters.

Muscle biopsies were taken from the middle gluteal muscle of 28 Standardbred trotters, 3-4 years of age. The 13 horses in Group T were trained consistently from 18 months of age, whereas the 15 horses in Group UT were not exposed to any systematic training before 3 years of age. Group T horses had a lower percentage of Type IIB fibres (31%) than did Group UT horses (39%). Citrate synthase (CS) activity, representing oxidative capacity, was higher in Group T (72 mmol kg-1 min-1) than in Group UT (47 mmol kg-1 min-1). Biopsies were taken from 4 horses in each group when they were foals and then annually until 3-4 years of age. Results from this study indicate that regular training of Standardbreds from 18 months of age resulted in increased CS activity and a decrease in the percentage of Type IIB fibres. This study shows that training, not growth, is the main factor that induces a high oxidative capacity and a high Type IIA/IIB fibre ratio in muscle of Standardbred trotters.     

Cross protection studies on Bordetella bronchiseptica in mice using an intracerebral challenge model.

Protective activities of heat-inactivated (60 degrees C for 30 min) merthiolate preserved Bordetella bronchiseptica and B. pertussis bacterins were compared in intraperitoneally immunized mice challenged intracerebrally (i.p./i.c.) or intraperitoneally (i.p./i.p.). In the i.p./i.c. assay (Kendrick test), a B. pertussis bacterin protected mice against challenge with B. pertussis 18-323, as well as against phase I cytotoxic and non-cytotoxic strains of B. bronchiseptica. A B. bronchiseptica bacterin, prepared from a phase I cytotoxic strain, gave protection against two phase I B. bronchiseptica strains, irrespective of their cytotoxin-production. A non-cytotoxic phase I strain of B. bronchiseptica elicited protection against the homologous strain only. Neither cytotoxic nor non-cytotoxic B. bronchiseptica strains protected mice challenged with B. pertussis 18-323. Vaccines prepared from phase III strains of B. bronchiseptica were not protective at all against any of the challenge strains. No such differences in the protective activities of the bacterins could be detected by the i.p./i.p. method. They seem to cross-protect equally well. The results indicate that the Kendrick test may be useful in testing potency of different B. bronchiseptica bacterins.     

Identification of some analogs of the hallucinogen phencyclidine.

The drugs 1-[1-(2-thienyl)cyclohexyl]piperidine, 1-[1-2-thienyl)cyclohexyl]pyrrolidine, 1-(-phenylcyclohexyl) morpholine, and 1-(1-phenyleyclohexyl) pyrrolidine are identified by spectroscopic techniques. The ultraviolet and proton magnetic resonance spectra of analogs are similar, but mass and infrared spectra are distinctly different, and reference spectra are provided. Gas-liquid ant thin layer chromatographic systems for the analysis are discussed.     

Phytoavailability of lead altered by two Pelargonium cultivars grown on contrasting lead-spiked soils

Purpose

This study assesses the potential of two contrasted fragrant Pelargonium cultivars to induce pH and dissolved organic carbon (DOC) changes in the soil solution, Pb speciation, and their subsequent effects on rhizosphere phytoavailable Pb.

Materials and methods

Rooted plantlets were grown in special devices, floating on aerated nutrient solution in PVC tanks. This setup allows roots to be physically separated, through a mesh, from a 3-mm soil matrix layer that can be considered as rhizosphere soil. Two contrasted soils, each spiked with Pb-rich particles, emitted from a battery recycling industry, were used at total burdens of 500 and 1500 mg Pb kg^?1 in addition to a control unspiked soil. Soil solution pH, phytoavailable Pb, DOC, Pb adsorption, precipitation on roots, and Pb phases in soil and plant were investigated.

Results and discussion

Attar of Roses (Attar) cultivar acidified its rhizosphere by 0.4 pH units in both spiked soils. Concolor Lace (Concolor) was unable to change soil solution pH on soil-1 and increased it by 0.7 units on soil 2. Concentrations of Pb in soil solution from Attar plants were always higher than those of Concolor ones. DOC contents of both unspiked soil-1 and soil-2 without plants were not significantly different. In the case of spiked samples, DOC contents in the rhizosphere soil were increased by three and two times for Attar and Concolor, respectively, compared to the unspiked soil without plant. Both cultivars were able to increase DOC contents, independent of soil type and level of contamination. Accumulation of Pb in shoots and roots was higher in Attar as compared to Concolor due to enhanced available Pb as a result of pH and DOC modifications of the rhizosphere soil. Significant amounts of Pb were adsorbed on roots of both cultivars. X-ray elemental analysis of precipitates on roots revealed the association of Pb with P in cylinder-like structures. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Pb was present, to a major extent in the inorganic form, mainly as PbSO₄ in the soil, whereas it was complexed with organic species within plant tissues. The conversion of Pb into organic species could decrease toxicity, may enhance plant tolerance, and could increase translocation.

Conclusions

Plant-induced changes were responsible for the modification of lead phases within the soil. Immobile forms present in the source leaded particles as well as in the soils were converted into soluble species, ultimately improving the phytoavailable or soil solubilized Pb.

     

Mammary carcinoma: enzymatic block in disialoganglioside biosynthesis

The sialyl transferase of disialoganglioside formation is depressed in mammary tumors induced in the rat by 7,12-dimethylbenz[a]anthracene. Specific activities of other glycosyltransferases of the pathway ceramide to monosialo-ganglioside are unchanged or elevated so that the ganglioside GM(1) accumulates and higher gangliosides are depressed. These findings with a solid tumor are critical to an involvement of gangliosides in the cell-surface changes of tumorigenesis.     

Efficacy of statistical process control procedures to identify deviations in continuously measured physiological and behavioral variables in beef heifers resulting from an experimentally combined viral–bacterial challenge

The objective of this experiment was to determine if statistical process control (SPC) procedures coupled with remote continuous data collection could accurately differentiate between animals experimentally inoculated with a viral–bacterial (VB) challenge or phosphate buffer solution (PBS). Crossbred heifers (N = 38; BW = 230 ± 16.4 kg) were randomly assigned to treatments by initial weight, average daily gain (ADG), bovine herpes virus 1, and Mannheimia haemolytica serum titers. Feeding behavior, dry matter intake (DMI), animal activity, and rumen temperature were continuously monitored remotely prior to and following VB challenge. VB-challenged heifers exhibited decreased (P < 0.01) ADG and DMI, as well as increased (P < 0.01) neutrophils and rumen temperature consistent with a bovine respiratory disease (BRD) infection. However, none of the heifers displayed overt clinical signs of disease. Shewhart and cumulative summation (CUSUM) charts were evaluated, with sensitivity and specificity computed on the VB-challenged heifers (n = 19) and PBS-challenged heifers (n = 19), respectively, and the accuracy was determined as the average of sensitivity and specificity. To address the diurnal nature of rumen temperature responses, summary statistics (mean, minimum, and maximum) were computed for daily quartiles (6-h intervals), and these quartile temperature models were evaluated separately. In the Shewhart analysis, DMI was the most accurate (95%) at deciphering between PBS- and VB-challenged heifers, followed by rumen temperature (94%) collected in the 2nd and 3rd quartiles. Rest was most the accurate accelerometer-based traits (89%), and meal duration (87%) and bunk visit (BV) frequency (82%) were the most accurate feeding behavior traits. Rumen temperature collected in the 3rd quartile signaled the earliest (2.5 d) of all the variables monitored with the Shewhart, followed by BV frequency (2.8 d), meal duration (2.8 d), DMI (3.0 d), and rest (4.0 d). Rumen temperature and DMI remained the most accurate variables in the CUSUM at 80% and 79%, respectively. Meal duration (58%), BV frequency (71%), and rest (74%) were less accurate when monitored with the CUSUM analysis. Furthermore, signal day was greater for DMI, rumen temperature, and meal duration (4.4, 5.0, and 3.7 d, respectively) in the CUSUM compared to Shewhart analysis. These results indicate that Shewhart and CUSUM charts can effectively identify deviations in feeding behavior, activity, and rumen temperature patterns for the purpose of detecting sub-clinical BRD in beef cattle.     

A modified laryngoplasty approach promoting ankylosis of the cricoarytenoid joint

Objective: To perform a modification to the standard laryngoplasty procedure in vivo that would result in ankylosis of the cricoarytenoid (CA) joint, and determine the stability provided to the abducted arytenoid in vitro. Study Design: Experimental study. Animals: Horses (n=8). Methods: Horses were assigned to either control laryngoplasty (n=3) or modified laryngoplasty (5) procedure. Endoscopic upper airway evaluations were used to measure right:left quotients 1 day and 3 months postoperatively to assess maintenance of abduction. Horses were euthanatized 3 months after surgery and larynges collected for measurement of translaryngeal impedance and histologic evaluation of CA joint ankylosis. Each specimen was exposed to increasing negative pressure with the sutures intact or cut while translaryngeal impedance was recorded. Data were analyzed using ANOVA with significance set at P<.05. Results: Loss of left arytenoid cartilage abduction at 3 months was greater in the control laryngoplasty group. Overall, impedance was significantly lower for the modified laryngoplasty group compared with the control laryngoplasty group and lower with the sutures intact than cut. Histologic evaluation of the joints confirmed fibrous bridging of the left CA joints of the modified laryngoplasty group. Conclusions: A modified laryngoplasty approach promotes ankylosis of the CA joint and decreases the loss of abduction of the arytenoid.