Myxoma virus induces apoptosis in cultured feline carcinoma cells

There is growing interest in utilizing replicating oncolytic viruses as cancer therapeutics agents. The effectiveness of myxoma virus-induced oncolysis was evaluated in two feline cancer cell cultures. Although myxoma virus is a rabbit-specific pathogen, protein expression driven by myxoma virus and production of infectious viral particles were detected. Cell death occurred in primary feline cancer cells within 48 h of inoculation with myxoma virus. Future studies to determine if other feline neoplasms are susceptible to myxoma virus infection are warranted.     

Bragg soybeans grown on a southern coastal plains soil i. dry matter distribution,nodal growth analysis,and sample variability

Yields of soybean [Glycine max (L.) Merr.] are affected by the manner in which available resources are partitioned into component plant parts. Little is known about these partitioning processes and much of what has been reported describes indeterminate cultivars or comes from other than field studies. A field investigation was conducted, therefore, on a Goldsboro loamy sand (Aquic Paleudult) to characterize in detail the growth and development of a determinate soybean cultivar ‘Bragg’. Soybean were grown in well watered field plots in four replications from each of which 4 nested samples of 0.3 m² each were combined at each sampling. Leaf area, dry matter production, internode length, and sample variability were determined nodally at 10‐ to 14‐day intervals from 7 July to 17 October. Plant components at each node were separated into stems, leaf blades, pods, and petioles. Primary and secondary branches were combined in the petiole fraction.

Maximum above ground plant dry weight achieved was 1027 g/m² and maximum combined nodal dry weight was 92 g/m² (at node 8), both occurring at the R7 growth stage. Canopy dry weight distribution over time was unique for each plant part. Growth analyses showed that RGR, NAR, LAR, and LWR declined with plant age at a rate that could be described with either linear or exponential models. A maximum CGR of 16.24 g/m²/day occurred at mid‐podfill and declined thereafter due to maturity. Leaf area per node peaked between nodes 7 and 12, decreasing uniformly toward the top of the canopy. Maximum nodal LAI was 0.79 at node 7 on 31 August.

Distribution of dry weight among parts varied with plant age and node position. Maximum dry weights of stems (276 g/m²), petioles (253 g/m²), and leaves (263 g/m²) were found during mid‐podfill. During mid‐August, the dry weights of the stems, petioles, and leaves were similar and approximately 250 g/m². Stem dry weights had the lowest coefficients of variation of all plant fractions once maximum dry weight was achieved. Internode length varied along the stem with the maximum at node 12. By bloom, expansion of the internodes lower than 12 had ceased; expansion of the eight higher internodes ceased three weeks later. During vegetative growth, the ratio of stem internodal dry weight to internodal length had peak values at the lowest and highest internodes. During reproductive growth, the ratio decreased linearly with internode number. Coefficients of variation (CV) for the combined weight of plant parts, and for stems, petioles, leaves, and pods were relatively constant during the season and were 24.8, 23.4, 38.2, 25.5, and 26.8%, respectively. The CV's for the combined weight of plant parts were somewhat higher at the lowest and uppermost nodes. This variability resulted from the abscission of petioles and leaves in the lower nodes and the initiation of leaves, petioles, and pods in the upper nodes where rapid growth and development was occurring. Time from node initiation to achievement of lowest stable CV was determined for each node and plant part. Plant node position and morphological part with the lowest CV was identified for each sampling date (and growth stage).     

High-Pressure Framework Silicates

Recent syntheses of high-pressure alkali and alkaline earth silicates reveal a class of framework structures with corner-linked 4- and 6-coordinated silicon. These compounds possess the structural formula (A4-2x1+Bx2+)SimVI(SinIVO2(m+n)+2), where x, m, and n specify the amounts of alkaline earth, 6-coordinated silicon, and 4-coordinated silicon, respectively. Appropriate values of m and n yield a range of high-pressure structures, from fully 4-coordinated to fully 6-coordinated silicate frameworks. Recognition of this class of framework silicates leads to predictions of high-pressure structures as well as room-pressure isomorphs of high-pressure silicates.     

Are Pharmacological Interventions Between Conception and Birth Effective in Improving Reproductive Outcomes in North American Swine?

The objective of this review is to evaluate the effectiveness of using pharmacological compounds on reproductive outcomes, particularly litter size, in North American swine. While the opportunity to improve reproduction in North American pigs exists, numerous hurdles need to be overcome in order to achieve measureable results. In the swine industry, the majority of piglet losses are incurred during pregnancy and around farrowing. Over the last 20 years, a reduction in losses has been achieved through genetic selection and nutritional management; however, these topics are the focus of other reviews. This review will evaluate attempts to improve litter size by reducing losses at various stages of the reproductive process, from the time of conception to the time of farrowing, using pharmacological compounds. Generally, these compounds are used to either alter physiological processes related to fertilization, embryonic attachment or uterine capacity, etc., or to facilitate management aspects of the breeding females such as inducing parturition. Although some of the pharmacological agents reviewed here show some positive effects on improving reproductive parameters, the inconsistent results and associated risks usually outweigh the benefits gained. Thus, at the present time, the use of pharmacological agents to enhance reproduction in North American swine may only be recommended for herds with low fertility and presents an avenue of research that could be further explored.     

Benign cranial mediastinal lesions in three cats

Cranial mediastinal lesions were detected in three cats, associated with respiratory impairment (case one), spontaneous pneumothorax (case two) and myasthenia gravis (case three), respectively. On gross and histological examination, the first case was considered either a lymphangioma or a branchial cystic mass of the thymic region of the mediastinum; a cystic lesion was suggested by sonographic detection of multiple anechoic cavitations within a circumscribed mass, while fine needle aspiration cytology excluded lymphosarcoma. The second case was diagnosed histologically as a cystic thymoma, but the third case was not examined microscopically. The masses were amenable to surgical excision in the first two cats, while this proved unnecessary in the third case because of resolution following treatment with dexamethasone. Corticosteroid responsiveness was unhelpful in distinguishing between these benign lesions and lymphosarcoma, as in two cases there was a partial or complete response to dosing with prednisolone or dexamethasone. These cases are presented to emphasise that conditions other than lymphosarcoma can produce cranial mediastinal lesions in cats, and that the prognosis for surgical treatment of lymphangiomas, multilocular thymic cysts and cystic thymomas can be excellent.     

Epidemiology of salmonellosis in the live sheep export industry

SUMMARY Salmonellosis in sheep was studied on 7 commercial voyages from Australia to the Middle East and in one animal house study. Faecal excretion of salmonellas was not a good indicator of pathological changes in the gastrointestinal tract. The ratio of the proportion of sheep excreting salmonellas to the proportion with histological lesions of salmonellosis ranged from 1:1 to 23:1. Increasing excretion rates in our studies indicated that most sheep would be exposed to infection, although deaths from salmonellosis were not spatially or temporally clustered as would be expected if challenge alone was a sufficient cause. We considered that inappetence predisposed to death from salmonellosis, and that sheep with inappetence were likely to be randomly distributed aboard ship. In the animal house study, histological lesions of salmonellosis were exclusively in inappetent sheep although almost all sheep excreted salmonellas in faeces. Lesions of salmonellosis were found only in sheep that were seriously ill or had died, which suggested that, under the conditions of lot-feeding and sea transport, most sheep with enteric lesions are likely to die. Lesions were not found in feeding controls. Adrenal gland weights, an indicator of stress duration and severity, were used to examine the temporal sequence of events in the development of salmonellosis. Weights were greater in sheep that died of inanition than in controls, suggesting that inappetent sheep were already stressed for that reason. The presence of enteric lesions of salmonellosis was associated with further increases in adrenal gland weights. In a small proportion of cases, septicaemic salmonellosis developed rapidly and without adrenal gland hypertrophy suggesting that the sheep succumbed before the adrenal glands had time to enlarge. We concluded that sheep were predisposed to salmonellosis by inappetence and that stress was involved in lesion development. We considered that the development of enteric lesions of salmonellosis, in the live export system, inevitably led to death.     

Antifreeze ingestion by dogs and rats: influence of stimulus concentration

Ingestive responses of 50 rats and 4 gastric-cannulated dogs to ethylene glycol-based antifreeze (AF) were found to be inversely related to concentration. The antifreeze was never preferred to water. Do thirsty animals that encounter weak AF solutions drink them solely for their water content, water-related oral tactile sensations, or both, being inadvertently poisoned in the process?     

A summary of state laws regulating youth operating farm tractors on highways

Driving farm tractors on highways is hazardous for youth due to the large speed differential between motor vehicles and agricultural vehicles, as well as recent increases in traffic volume on many rural roads. In 1994, the state of Wisconsin enacted legislation requiring youth who operate farm tractors on highways to complete a tractor and machinery certification course. We were interested in finding out whether other states have similar requirements. The purpose of this project was to collect and summarize state laws regulating youth who operate farm tractors on highways in the U.S. A systematic method was used that included an initial Lexis-Nexis database search followed by internet searches in combination with follow-up email and telephone communications when missing or unclear results were obtained. The findings show that 14 states have legislation addressing youth who operate farm tractors on highways. The content of these statutes varies, but includes driver's license or educational requirements, as well as regulations concerning the ages, locations, and/or times of day when youth may drive farm machinery on highways. This compilation of state laws will be useful information for agricultural safety professionals in designing effective outreach programs. A synthesis of the findings may also lead to the development of model legislation or inform future research efforts aimed at preventing youth farm tractor crashes on highways.