Expression analysis of selected immune-relevant genes in channel catfish during Edwardsiella ictaluri infection.

Channel catfish Ictalurus punctatus were intraperitoneally challenged with the bacterium Edwardsiella ictaluri (the causative agent of enteric septicemia of catfish), and the expression of genes presumed to function in the inducible innate defense was evaluated. End-binding protein 1 (EB1), beta1-integrin, natural-resistance-associated macrophage protein (Nramp), heat shock protein 70 (Hsp70), serum amyloid P (SAP), and transferrin gene expression profiles were determined using quantitative reverse-transcriptase-polymerase chain reaction on liver, anterior kidney, spleen, and gut. Fish were subsampled at 0, 24, 48, 72, and 96 h after bacterial or phosphate-buffered-saline injection. Posterior kidney sampling demonstrated increasing bacterial counts at 24-48 h postinjection (hpi), followed by a plateau to 96 hpi. The transferrin and SAP transcripts were liver specific. The other genes were expressed in all four tissues. In bacterially infected fish, expression of EB1 (anterior kidney, spleen, and liver), Hsp70 (anterior kidney and spleen), and Nramp (spleen and gut) significantly increased by 48 hpi. Transferrin was strongly up-regulated and SAP was downregulated by 72 hpi, indicating positive and negative acute-phase reactants, respectively. The data indicate a substantial response of innate immunity effector cells by 48 hpi, followed by suppression of bacterial growth and induction of the acute-phase response. This suggests that the 48-72-hpi time frame is critical in our model for evaluating the effectiveness of innate defenses.

Histologic comparison of canine skin biopsies collected using monopolar electrosurgery, CO2 laser, radiowave radiosurgery, skin biopsy punch, and scalpel.

OBJECTIVE: To compare the histologic appearance of canine skin biopsies collected by use of a scalpel, skin biopsy punch, monopolar electrosurgery, CO2 laser, and radio wave radiosurgery in fully rectified wave form (RWRS). STUDY DESIGN: Experimental, randomized design. ANIMALS: Healthy adult grayhounds (n=4). METHODS: Skin biopsies were collected using 5 techniques. Cut margins of biopsy specimens and adjacent peripheral skin were evaluated using light microscopy to compare penetration of the dermis by tissue carbonization (char). RESULTS: No char occurred in skin specimens collected by biopsy punch and scalpel. Char penetration occurred in all specimens collected by electrosurgery, CO2 laser, and RWRS. Mean char penetration in skin biopsies collected by RWRS (0.158 mm) was significantly less than for monopolar electrosurgery (0.223 mm) and CO2 laser (0.215 mm). Mean char penetration in adjacent peripheral skin surrounding biopsies collected by RWRS (0.171 mm) was significantly less than monopolar electrosurgery (0.255 mm) but not less than CO2 laser (0.215 mm, P<.07). CONCLUSIONS: RWRS (blended waves in cut-coagulate mode) caused less lateral thermal damage to canine skin biopsies than monopolar electrosurgery and CO2 laser and less lateral thermal injury to peripheral skin than monopolar electrosurgery. CLINICAL RELEVANCE: Excision of canine skin biopsies with heat-generating devices may not allow reliable histologic interpretation, particularly when assessing margins of small biopsy specimens. RWRS may be less traumatic to canine skin than monopolar electrosurgery and CO2 laser when used to make incisions.

Toggle rod stabilization for treatment of hip joint luxation in dogs: 62 cases (2000-2005).

OBJECTIVE: To determine outcome of open toggle rod stabilization in dogs with luxation of the hip joint. Design-Retrospective case series. ANIMALS: 62 dogs. PROCEDURES: Information on signalment, surgical procedure, and postoperative care was obtained from the medical records. A questionnaire was sent to all owners to solicit follow-up information. RESULTS: The distribution for time between luxation and surgery was bimodal, with 24 (39%) dogs examined < or = 2 days after injury and 23 (37%) examined > 7 days after injury. Postoperative complications developed in 16 of the 62 (26%) dogs, with complications developing within 1 week after surgery in 10 of the 16. The most common complication was reluxation, which occurred in 7 dogs. Dogs in which surgery time was < 2 hours were significantly less likely to have a reluxation (2/40 [5%]) than were dogs in which surgery time was > or = 2 hours (5/22 [23%]). When asked to rate current limb function (0 = no lameness and 5 = non-weightbearing lame) a minimum of 6 months after surgery, 23 of 27 (85%) owners indicated a score of 0 or 1. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggest that toggle rod stabilization is an effective treatment for hip joint luxation in dogs. However, complications, particularly reluxation, were common.

Effects of subminimum inhibitory concentrations of antibiotics on the Pasteurella multocida proteome.

Subminimum inhibitory concentrations (sub-MICs) of antibiotics can be therapeutically effective, but the underlying molecular mechanisms are not well-characterized. We analyzed the Pasteurella multocida proteome response to sub-MICs of amoxicillin, chlortetracycline, and enrofloxacin using isotope-coded affinity tags (ICAT). There were parallel effects on inhibition of growth kinetics and suppression of protein expression by clusters of orthologous groups (COG) categories. Potential compensatory mechanisms enabling antibiotic adaptation were identified, including increased RecA expression caused by enrofloxacin.

The embryo lethality of Escherichia coli isolates and its relationship to various in vitro attributes.

Based on the hypothesis that bacteria with minimal embryo lethality might be good candidates for vertical transmission, 103 lactose-positive Escherichia coli isolates were collected from different broiler-related conditions (sources) and analyzed using a variety of in vitro assays: biochemical profiles, sensitivity to antimicrobials, and the presence of plasmids in the 2000- to 16,000-base pair range. The results of these assays were analyzed to determine if they were associated with, or could be used as predictors of, the degree of lethality these isolates produced in 12-day-old embryos. In addition, the in vitro assay results were analyzed to determine if there was any correlation between any particular pair of factors. On the basis of biochemical profiles, the isolates were classified into 17 different groups; however, only a limited number of biochemical reactions separated a majority of the isolates. The isolates varied considerably in the number and size of plasmids they contained and in their sensitivity to the antimicrobials evaluated. The isolates also varied in their ability to kill chicken embryos--killing from 0% to 100% of those inoculated--yet significant differences were detected in lethality based on source and biochemical profile of the isolate. In addition, a predictive model for embryo lethality was constructed and evaluated based on three characteristics of these 103 isolates, namely, their ability to ferment raffinose and sorbose and their sensitivity to gentamicin.

Role of the tendons of the biceps brachii and infraspinatus muscles and the medial glenohumeral ligament in the maintenance of passive shoulder joint stability in dogs.

OBJECTIVE: To objectively evaluate the effect of transecting the tendon of the biceps brachii muscle (BBT), tendon of the infraspinatus muscle (IFS), or medial glenohumeral ligament (MGHL) on shoulder joint stability in canine cadavers. SAMPLE POPULATION: 81 forelimbs from mature dogs. PROCEDURE: Cadaver forelimbs were placed in a testing frame and axially preloaded with 4 kg of weight. Shoulder joint stability was tested in neutral joint position, flexion, and extension before and after transection of the BBT (n = 37), IFS (37), or MGHL (7). Humeral translation relative to the glenoid was induced by applying a 3-kg load in each of 3 directions (cranial, lateral, and medial) and quantitatively measured by use of an electromagnetic motion tracking system. Peak translational data were compared in each joint position before and after transection of the BBT, IFS, or MGHL. RESULTS: When tested in neutral position, the cranial, lateral, and medial translation of the humerus was significantly increased after BBT transection. In the flexed position, translation of the humerus in the cranial and lateral directions was significantly increased after BBT transection. In the extended position, the medial translation of the humerus was significantly increased after BBT transection. Complete medial luxation of all humeral heads occurred following transection of the MGHL. CONCLUSIONS AND CLINICAL RELEVANCE: The BBT contributes to passive shoulder joint stability in dogs, particularly in the neutral and flexed positions. It also provides medial stability during shoulder joint extension. Complete luxation of the joint occurs when the MGHL is transected.

Relationship between red blood cell thiopurine methyltransferase activity and myelotoxicity in dogs receiving azathioprine.

Thiopurine methyltransferase (TPMT) produces inactive metabolites of azathioprine and, in humans, has a variable amount of activity. Humans with low TPMT activity commonly develop myelotoxicity when receiving azathioprine. Our study sought to characterize the distribution of TPMT activity in a population of dogs and to determine whether the pretreatment knowledge of red blood cell (RBC) TPMT activity could predict myelotoxicity in dogs receiving azathioprine. RBC TPMT activity was measured in 299 healthy dogs, and 9 dogs that represented a wide range of enzyme activity received azathioprine at a standard therapeutic dose for 30 days. TPMT activity in healthy dogs was log normally distributed and varied over an approximately 7-fold range. Geometric mean, minimum, and maximum RBC TPMT activities were 37.1, 16.3, and 115 nmol per gram of hemoglobin (gHb) per hour, respectively. TPMT deficiency was not identified. Two populations of TPMT activity in dogs were detected by statistical modeling (commingling analysis). Dogs with intermediate TPMT activity (14-38 nmol/gHb/h) receiving azathioprine had significantly lower neutrophil counts during week 4 than during weeks 0-3, whereas those with high activity (>39 nmol/gHb/h) did not have a significant change in neutrophil count. An analysis of TPMT activity in 6 dogs with a history of azathioprine-associated myelotoxicity in a clinical setting revealed either intermediate or high TPMT enzyme activity in all dogs, suggesting that TPMT activity, as measured in RBCs, is not the sole cause of severe azathioprine-associated myelosuppression in dogs.

Effects of pico-tesla electromagnetic field treatment on wound healing in rats.

OBJECTIVE: To evaluate the effects of a pico-tesla electromagnetic field (PTEF) on healing of sutured and open skin wounds and clinicopathologic variables in rats. ANIMALS: 64 male Fischer-344 rats. PROCEDURE: An incision made in the dorsal aspect of the neck was sutured (n = 32) or left open to heal (32). In each group, 16 rats were not PTEF-treated (controls). Wound treatment consisted of exposure to a PTEF once daily. Rats in each group were euthanatized at days 2, 4, 7, and 14. Wounds were evaluated via tensiometry (sutured wounds), digital planimetry (open wounds), laser Doppler perfusion imaging, bacteriologic culture, and histologic examination. Blood samples were collected from all rats for analysis. RESULTS: At day 14, sutured wounds in PTEF-treated rats were stronger (ultimate stress) and tougher (strain energy) than were sutured wounds in control rats. Open wounds in PTEF-treated rats contracted more quickly at days 2 and 4 than did those in control rats. Compared with control wounds, histologic changes (indicative of improved healing) in sutured and open wounds in PTEF-treated rats were detected as early as day 4. Laser Doppler perfusion measurements, results of CBCs, serum biochemical analyses, and bacteriologic cultures were not different between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to the PTEF caused no adverse effects on clinicopathologic, histologic, or bacteriologic variables tested in this study. It appears that PTEF is a safe form of adjuvant treatment for wounds and improves strength of sutured wounds and speeds contraction of open wounds.

Postoperative integrity of veterinary surgical gloves.

A multicenter, prospective study was performed to document the incidence of defective gloves postoperatively in veterinary surgery and to correlate defects with a variety of influencing factors. Gloves were collected after surgical procedures performed by the small animal clinical services at two veterinary teaching hospitals and one institution's student surgery laboratories. Gloves were evaluated for defects using electrical resistance testing. The overall incidence of glove defects was 23.3%. Significantly more defects occurred in gloves used for nonsoft-tissue procedures and in gloves worn on the nondominant hand. Eighty-four percent of all defects occurred in procedures lasting >60 minutes. No differences were detected in the brands of gloves used nor among surgeons of different experience levels. The individuals performing the surgery were not able to accurately predict the presence of a defect in their gloves. Surgeons should remain alert for possible glove defects and consider measures such as changing gloves every 60 minutes or double-gloving to minimize potential complications.