Biochemical analysis of normal articular cartilage in horses

Articular cartilage specimens from the distal articular surface of 32 radiocarpal bones from 24 2- to 5-year-old horses were analyzed. The total collagen content was determined on the basis of the 4-hydroxyproline content, using a colorimetric method. A method for estimating the proportions of types-I and -II collagen by measuring spectrophotometric densities of specific cyanogen bromide peptide bands from mixtures of types-I and -II collagen on sodium dodecyl sulfate-polyacrylamide gels was used. The cyanogen bromide peptides representative of each collagen types-I and -II were identified. The peptide ratios were then computed for each of several standards of type-I and -II mixtures. A standard curve was derived from the correlation between these ratios and the corresponding proportions of type-II collagen in standard mixtures. Galactosamine and glucosamine content (hexosamines) were measured by ion chromatography. The galactosamine-to-glucosamine ratio, chondroitin sulfate and keratan sulfate values, and total glycosaminoglycan content were derived from the measured hexosamine content. The total collagen content averaged 556 mg/g (55.6 mg/100 mg) of tissue (dry weight, [dw]). Type-II collagen was the major collagen type in normal articular cartilage specimens. The ratio of the area under the alpha 1 (II)CB10 peak to the area under the alpha 1 (I)CB 7,8 + alpha 1 (II)CB11 peak was a second-order polynomial function of the proportion of type-II collagen in the specimens. The mean galactosamine and glucosamine content were 20.6 mg/g and 7.9 mg/g (dw), respectively. The mean galactosamine-to-glucosamine ratio was 3.74 +/- 0.62.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abomasal intubation of young calves.

A nonsurgical method for passing a tube into the abomasum of young calves was developed. The tube described may be used for infusion into, or sampling from, the abomasum. The tube was successfully passed into the abomasum of all eight calves used. In two calves two to four days old and in two neonatal calves (greater than 24 h old) reticular groove closure was stimulated by providing a suckling stimulus but in four neonatal calves, passage of the tube was successful without the suckling stimulus. Placement of the tip of the tube was verified by auscultation and, in two calves, by radiography.     

Attenuation of Eimeria species: further characterisation of two lines of Eimeria mitis

The immunogenicity of a 'precocious' and attenuated line (HP10) of Eimeria mitis was studied and the stability of attenuation of two precocious lines was compared with that of an embryo-adapted line. Chicks housed in wire-floored cages and given 1 X 10(5) oocysts of the HP10 line were protected against challenge with the parent Houghton strain and two field strains, but remained partially susceptible to the Durham and one other field strain. However, when chicks were kept in litter pens so that reinfection could occur freely, inoculation with as few as 1 X 10(3) oocysts of the precocious line resulted in complete immunity to both the Houghton and Durham strains for at least five weeks afterwards. The stability of attenuation of the precocious and embyro-adapted lines was examined by relaxing the selection pressures used to produce attenuation and then testing the virulence of the resulting lines. The precocious lines remained attenuated after several consecutive relaxed passages, in contrast to the embyro-adapted line which showed a marked reversion to virulence after six passages in chickens.     

Phenobarbitone-responsive hypersialism in two dogs

Two dogs were examined for hypersialism associated with non-painful, symmetrical enlargement of both mandibular salivary glands. These signs were accompanied by inappetence and weight loss. The underlying cause of the problem could not be determined despite extensive investigations including fine needle aspiration biopsy of affected salivary glands. Hypersialism and mandibular salivary gland enlargement resolved completely during pheno-barbitone administration.     

Effects of repeated Strongylus vulgaris inoculations and concurrent ivermectin treatments on mesenteric arterial lesions in pony foals

Eight of 10 pony foals reared under helminth-free conditions were inoculated PO with 50 Strongylus vulgaris infective larvae/week for 4 weeks, at which time 1 foal died of acute verminous arteritis. Inoculation of 7 remaining foals continued at 2-week intervals for 20 weeks. Of the 7 foals, 3 were treated with ivermectin (0.2 mg/kg of body weight) in an oral paste formulation at experiment weeks 8, 16, 24; 4 foals were not treated. Two foals were not inoculated or treated and served as controls. After the first ivermectin treatment, ivermectin-treated foals had fewer days (12 +/- 2.9) with rectal temperatures greater than 38.6 C than did nontreated foals (23.3 +/- 3.8). Mean baseline rectal temperatures were 38 +/- 0.2 C. Adverse clinical reactions to ivermectin treatment were not observed in foals. Foals were euthanatized and necropsied 3 weeks after the last ivermectin treatment (week 24). Ivermectin was effective in reducing S vulgaris arterial larval and intestinal adult parasite numbers by 100% in 3 treated foals. Strongylus vulgaris arterial larvae and/or adults were recovered from all 4 nontreated inoculated foals. One nontreated inoculated foal lacked arterial larvae or active arterial lesions, indicating that protective resistance had developed in this individual. Marked gross and histopathologic lesions typical of chronic S vulgaris infection were observed in the 3 nontreated inoculated foals with arterial larvae. Repeated killing of intra-arterial S vulgaris fourth-stage larvae in ivermectin-treated foals did not exacerbate lesions associated with verminous arteritis or induce unique lesions associated with repeated destruction of arterial larvae.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preference for and performance of some Australian native plants grown as hedges

Indigenous and other native plants are commonly restricted to informal or naturalistic designed landscapes. This research project investigates the use of native plants as a formal landscape element – the hedge. A multidisciplinary approach was used with distinct horticultural and social science components. The first study explored the response of 14 native and one exotic species to hedging every 4 months. Digital imaging techniques were used to measure changes in growth, density and canopy distribution. All species responded well to hedging, greatly increasing in density. Significant differences in growth rates and shoot regrowth patterns were recorded between the species. Some hedges grown from genetically diverse plant material had noticeable morphological variations and would be more suited to use as informal hedges, however growth rates were found to be a much better predictor of hedging performance than genetic uniformity. A second study explored gardeners’ (n=162) preference for these native hedges. Photomontages were created of the hedges grown in the horticultural experiment and a photo-questionnaire distributed to several groups of gardeners. The preference results showed that many gardeners did like some Australian plants used as hedges. Significant differences in preference were found between species. A principal components analysis found that factors positively affecting preference for hedges included neatness, foliage colour (green and grey), presence of flowers and the absence of visible woody stems. In general, genetically diverse hedges were slightly less preferred than genetically uniform hedges, but some genetically diverse hedges were highly preferred. Personal style preferences based on gardeners’ expressed gardening behaviour were also observed, with grey and softer hedges preferred by those participants with low-maintenance, drought tolerant or native gardens.