Connectivity of lobster (Homarus americanus) populations in the coastal Gulf of Maine: part II. Coupled biophysical dynamics

We used a coupled biophysical model to investigate larval transport and connectivity patterns in the Gulf of Maine lobster ( Homarus americanus ) population. Biological 'particles' were released at over 21 000 locations every 10 days over a 4-month hatching period, and were followed from hatching through late postlarval stage. In addition to circulation and dispersion, model calculations included spatial patterns of egg production, temporal patterns of hatching, temperature-dependent development, vertical distribution and mortality. We ran the model for three larval production seasons using the same hatching patterns and individual-based modeling parameters but different flow patterns in the coastal current system. Model results gave distribution and abundance patterns of competent postlarvae that closely resembled observed, alongshore patterns of lobster settlement density. We evaluated the relative contribution of all source regions to the total number of competent postlarvae in a series of medium-size zones along the coastal shelf, many of which are used in lobster management. Connectivity depended on many factors, including patterns of egg production and transport, and the location and size of the receiving zones. Self recruitment ranged from a few percent to >90% of competent postlarvae. Although it was common for postlarvae to come from many, often distant, sources, most of the competent postlarvae in a zone originated within one to two zones in the prevailing 'up-stream' direction, forming shorter connections along the coast than the energetic currents might otherwise suggest. Inshore migrations during summer hatching may contribute to these shorter patterns of connectivity. Transport in the prevailing 'upstream' direction was also indicated.     

MAGNETIC RESONANCE IMAGING CONTRAST ENHANCEMENT OF THE TRIGEMINAL NERVE IN DOGS WITHOUT EVIDENCE OF TRIGEMINAL NEUROPATHY

Brain magnetic resonance images from 42 dogs imaged between 2002 and 2007 were reviewed retrospectively to establish the incidence of trigeminal nerve contrast enhancement. These dogs had otherwise normal MR images and no clinical evidence of trigeminal nerve disease. Contrast enhancement of the entire trigeminal nerve was seen in 39 dogs and in the region of the trigeminal ganglion in all 42 dogs. When contrast enhancement of the trigeminal nerve was observed, the intensity was subjectively less than or equal to that of the pituitary gland. Contrast enhancement of the trigeminal nerve was seen in 42 dogs with no clinical evidence of trigeminal nerve pathology.     

Proinflammatory cytokine responses of cultured equine keratinocytes to bacterial pathogen‐associated molecular pattern motifs

Reasons for performing study: Further knowledge of equine keratinocyte physiology and keratinocyte response to various stimuli is important in developing a better understanding of disease states involving the epidermis. Objectives: To assess the inflammatory cytokine response of cultured equine keratinocytes to various pathogen‐associated molecular pattern molecules (PAMPs) from both Gram‐negative and positive bacteria likely to be present in equine sepsis. Methods: Keratinocytes were isolated from skin of 2 horses and primary cultures performed. Keratinocytes were harvested for RNA extraction after exposure to lipopolysaccharide (LPS), lipoteichoic acid (LTA), peptidoglycan (PGN), bacterial DNA (CpG), flagellin or maintained in medium (controls) for 4 or 24 h. Real time‐quantitative PCR was used to quantify interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6) and CXCL8 mRNA concentrations. Results: Increases (P<0.05) in IL‐1β, IL‐6 and CXCL8 mRNA concentrations were induced by LPS exposure compared to controls. Increased mRNA concentrations of both IL‐6 and CXCL8 were also noted (vs. controls) upon exposure to flagellin. Overall, responses were greater at 4 h. No increases (P>0.05) in cytokine expression by keratinocytes were present after LTA, PGN or CpG exposure. Conclusions: Increased proinflammatory cytokine expression in response to LPS and flagellin indicate that equine keratinocytes have functional TLR4 and TLR5 receptor signalling. However, the lack of keratinocyte stimulation by PGN, LTA or CpG provides no evidence for functional TLR2, TLR9 or NOD receptor signalling. These results suggest that equine keratinocytes are more responsive to PAMPs usually associated with Gram‐negative sepsis and unresponsive to PAMPs most commonly associated with Gram‐positive sepsis. Potential relevance: The increased incidence of injury of epidermal structures in clinical cases of Gram‐negative (vs. Gram‐positive) sepsis in the horse may be due to a lack of functional TLR signalling for Gram‐positive PAMPs in the equine keratinocyte.     

Closed One-Stage Functional End-to-End Jejunojejunostomy in Horses With Use of Linear Stapling Equipment

Objective—To use gastrointestinal linear stapling instrumentation to perform a closed one-stage functional end-to-end jejunojejunostomy in adult horses as an alternative to a stapled side-to-side jejunojejunostomy.
Study Design—Clinical outcome, anatomic and histological architecture, and anastomotic dimensions were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Animals or Sample Population—18 adult horses.
Methods—The anastomosis and peritoneal cavity were inspected for adhesions. The diameter and circumference of the anastomosis and jejunum oral and aboral to the anastomosis were determined from digitized contrast radiographs and linear measurements. Healing of anastomotic sites was evaluated histologically.
Results—Three horses were euthantized in the immediate postoperative period. In the 15 surviving horses, there were no peritoneal adhesions or distortion of the anastomoses and stomas remodeled in an end-to-end fashion. The mean anastomotic staple line (7.48 cm) and mucosa (6.89 cm) diameters were significantly ( P < .05) larger than the mean jejunal diameter oral (6.03 cm) and aboral (6.01 cm) to the anastomosis. The mean anastomotic luminal circumference (13.61 cm) was significantly ( P < .01) larger than the mean oral (11.43 cm) and aboral (11.12 cm) jejunal circumference. Histologically, there was adequate mucosal and muscularis mucosae reapposition with a moderate degree of fibrosis and inflammation.
Conclusions —Closed one-stage functional end-to-end jejunojejunostomy resulted in an acceptable functional anastomosis.
Clinical Relevance —This technique appears to be an acceptable alternative to linearly stapled, side-to-side jejunojejunostomies performed in horses.     

Exploration of developmental approaches to companion animal antimicrobials: providing for the unmet therapeutic needs of dogs and cats

AAVPT Workshop White Paper Committee. Exploration of developmental approaches to companion animal antimicrobials: providing for the unmet therapeutic needs of dogs and cats. J. vet. Pharmacol. Therap. 33 , 196–201. The American Academy of Veterinary Pharmacology and Therapeutics (AAVPT) and the United States Pharmacopeia (USP) co‐sponsored a workshop to explore approaches for developing companion animal antimicrobials. This workshop was developed in response to the shortage of antimicrobials labeled for dogs and cats, as there is a shortage of approved antimicrobials for the range of infectious diseases commonly treated in small animal practice. The objective of the workshop was to identify alternative approaches to data development to support new indications consistent with the unmet therapeutic needs of dogs and cats. The indications for currently approved antimicrobials do not reflect the broader range of infectious diseases that are commonly diagnosed and treated by the veterinarian. Therefore, the labels for these approved antimicrobials provide limited information to the veterinarian for appropriate therapeutic decision‐making beyond the few indications listed. Industry, veterinary practice, and regulatory challenges to the development of new antimicrobial indications were discussed. The workshop resulted in short‐ and long‐term recommendations. Short‐term recommendations focus on the use of additional data considerations for product labeling. Long‐term recommendations center on legislative or regulatory legal initiatives. The workshop recommendations will need collaboration from industry, academia, and regulatory authorities and a legal shift in the drug approval and availability processes.