Dental dolorimetry for the evaluation of an analgesic agent in the horse

A monopolar electrode was implanted surgically in the canine tooth dentine layer to evaluate pain threshold responses of horses. A constant-current stimulator was used to deliver a known electrical current to the tooth pulp nerve. A single stimulus of 2-ms duration, repeated at greater than or equal to 20-s intervals, was used to elicit a head lift response. The lowest current level that produced 3 positive head lift responses was recorded as the pain threshold of the horse. The testing technique, dental dolorimetry, was easily performed. Tooth pulp pain thresholds (TPPT) were established on 8 nonmedicated adult male horses. Electrodes were nonreactive and remained functional for up to 98 days. Base-line TPPT values were consistent with repeated measurements on the same day and measurements on subsequent test days. The quantity of electrical current necessary to elicit the TPPT was increased after administration of xylazine HCl as a test analgesic.     

Effects of increased dosages of the Mycoplasma gallisepticum vaccine MYCOVAC-L in layer chickens subsequently challenged with virulent M. gallisepticum: egg production and serologic response

Ten-week-old Hy-Line Commercial W-36 pullets were spray-vaccinated with MYCOVAC-L at the manufacturer's recommended dosage (1x) or at 15 times that rate (15x). At 22 or 45 wk of age, subsets of 1x- and 15x-vaccinated pullets were challenged with the virulent Mycoplasma gallisepticum (MG) strain Rlow. Percent hen-day egg production was determined through week 55. Analyses for treatment effects on overall (22-56 wk) percent hen-day egg production revealed no significant differences between nonchallenged 1x and nonchallenged 15x MYCOVAC-L treatments. Among 1x MYCOVAC-L-vaccinated groups, Rlow challenge at 45 wk corresponded to significantly (P < or = 0.01) lower overall egg production compared with the unchallenged 1x-vaccinated control (70.88% vs. 79.15%, respectively). Conversely, at the 15x MYCOVAC-L dosage level, overall egg production was not significantly affected by virulent MG challenge at 45 wk compared with its unchallenged counterpart (84.09% vs. 81.03%, respectively) and could indicate increased protection from virulent MG challenge. Serologic monitoring indicated the virulent MG challenge was consistently (100%) associated with seroconversion. Comparisons among the nonchallenged experimental treatments indicated that vaccinations at the 15x MYCOVAC-L dosage rate were associated with a greater seroconversion rate at weeks 21, 27, and 44, but not at week 50.     

Interstitial collagenase is a Brownian ratchet driven by proteolysis of collagen

We show that activated collagenase (MMP-1) moves processively on the collagen fibril. The mechanism of movement is a biased diffusion with the bias component dependent on the proteolysis of its substrate, not adenosine triphosphate (ATP) hydrolysis. Inactivation of the enzyme by a single amino acid residue substitution in the active center eliminates the bias without noticeable effect on rate of diffusion. Monte Carlo simulations using a model similar to a "burnt bridge" Brownian ratchet accurately describe our experimental results and previous observations on kinetics of collagen digestion. The biological implications of MMP-1 acting as a molecular ratchet tethered to the cell surface suggest new mechanisms for its role in tissue remodeling and cell-matrix interaction.     

Review of carrot fly control in Northern Europe – 20091

In February 2009, the European and Mediterranean Plant Protection Organization (EPPO) held a workshop to discuss the management of carrot fly (Psila rosae) within Europe. Prior to the workshop, participants completed a questionnaire about carrot fly and current control methods and some of the information is summarised in this paper. In general, this pest is controlled adequately at present, but there is a heavy reliance on insecticides. The responses to the questionnaire highlighted a number of issues, in particular: the limited range and efficacy of the insecticides available at present, concerns about the availability of effective control measures in the future and a need for improvements in the targeting of treatments through forecasting and monitoring and the use of treatment thresholds.     

Testing and improving the effectiveness of trap crops for management of the diamondback moth Plutella xylostella (L.): a laboratory‐based study

BACKGROUND: The aim of this study was to assess white mustard (Sinapis alba L.) as a trap crop for diamondback moth [Plutella xylostella (L.)] on cauliflower [Brassica oleracea (L.) var. Lateman]. Moth behaviour on these plants and the importance of plant age and size in maintaining pest preference for trap crop plants were also investigated. RESULTS: Three times as many eggs were laid on cauliflower plants that were unprotected than on plants protected by a trap crop of white mustard. Moths remained longer on the mustard plants as a result of a doubling in the mean duration of information‐providing behaviours. Plant age had little effect on P. xylostella host preference. When plant age was constant, percentage oviposition on mustard was higher when these were larger (93%) than copresented cauliflower plants, compared with when they were smaller (68%). CONCLUSION: Trap cropping with white mustard may reduce the incidence of P. xylostella in cauliflower crops. The pest management benefits of trap crops may be maximised by using trap crop plants that are larger than the main crop plants, although relatively smaller trap crop plants may still be preferred as hosts for P. xylostella per se. Copyright © 2009 Society of Chemical Industry     

A chronicle of serologic response in commercial layer chickens to vaccination with commercial F strain Mycoplasma gallisepticum vaccine

Vaccination of multi-age layer operations, wherein one million plus commercial layer chickens are housed, has been spurious until the development of a self-propelled, constant-speed spray vaccinator. Still, even with its use, live Mycoplasma gallisepticum (MG) vaccinations have been questionable in terms of seroconversion. Using the vaccinator as a research tool over the past 5 yr, factors have been elucidated which impact seroconversion to one live MG vaccine in particular, the F strain of MG (FMG). These factors include the type of nozzle used to spray the vaccine, the temperature of the water used to rehydrate and administer the vaccine, and the pH and osmolarity of the fluid used to apply the vaccine. In the present study, one farm was monitored for its seroconversion rates over 4 1/2 yr, during which time the FMG vaccination protocol was amended as factors were identified that enhanced seroconversion rates. The results of this study showed that implementation and inclusion of the optimized factors into the vaccination protocol for FMG enhanced seroconversion rates because they went from an initial 50%-55% positive seroconversion rate to a consistent 100% positive seroconversion rate over the 56-mo study period.     

REVIEW ARTICLE: An integrated view on how the management of the dry period length of lactating cows could affect mammary biology and defence

The dry period is necessary to facilitate cell turnover in the bovine mammary gland and to optimize milk production in the next lactation. An 8‐week dry period has long been the golden standard of management for dairy cows. Genetic improvements and new management technologies have led to higher milk production and a need for re‐evaluation of the dry period length. Over the last decade, dry period length has been proposed to be shortened or eliminated mainly from an economic point of view. However, the influence of modified dry period length on the immune defence of the bovine mammary gland and the occurrence of new intramammary infections has not yet been appreciated. The objective of this review is to discuss the bovine mammary gland biology, defence and systemic health when the dry period length is modified. Shortening or eliminating the dry period may minimize or remove the impact of milk accumulation at dry off, thereby lessening the immunodeficiency of the dam that is characteristic of this period. Composition of mammary secretions may change and the extent of tissue remodelling may be reduced when the dry period is reduced or eliminated. Additionally, impact of the dry period length on energy and nutritional status, and on hormonal and local regulatory factors, lead us to hypothesize that changing the dry period length might also affect the response to intramammary infection. It is concluded that there is a need to integrate mammary gland biology and defence mechanisms in studies dealing with modified dry period lengths.     

How consistent is the advice from stock assessments? Empirical estimates of inter-assessment bias and uncertainty for marine fish and invertebrate stocks

Fishery management frequently involves precautionary buffering for scientific uncertainty. For example, a precautionary buffer that scales with scientific uncertainty is used to calculate the acceptable biological catch downward from the overfishing limit in the US federal fishery management system. However, there is little empirical guidance to suggest how large buffers for scientific uncertainty should be. One important component of uncertainty is variation among different assessments of the same stock in estimates of management-relevant quantities. We analysed commercially exploited marine fish and invertebrate stocks around the world and developed Bayesian hierarchical models to quantify inter-assessment variation in terminal year biomass and fishing mortality estimates, reference points, relative biomass and fishing mortality estimates, and overfishing limits. There was little evidence of inter-assessment bias; stock assessment estimates in the terminal year of the assessment were not consistently higher or lower than estimates of the same quantities in future years. However, there was a tendency for extreme values from the terminal year to be pulled closer to the mean in future years. Inter-assessment variation in all estimates differed across regions, and a longer inter-assessment interval generally resulted in greater variation. Inter-assessment uncertainty was greatest for estimates of the overfishing limit, with coefficients of variation ranging from 17% in Europe (non-EU) to 107% for Pacific Ocean pelagic stocks. Because inter-assessment variation is only one component of scientific uncertainty, we suggest that these uncertainty estimates may provide a basis for determining the minimum size of precautionary buffers.