Changes in volatile terpene and diterpene resin acid composition of resistant and susceptible white spruce leaders exposed to simulated white pine weevil damage

Induced (traumatic) resin in white spruce (Picea glauca (Moench) Voss) leaders resistant or susceptible to the white pine weevil (Pissodes strobi Peck) was analyzed for volatile terpenes and diterpene resin acids after simulated white pine weevil damage. Leaders from 331 trees were wounded just below the apical bud with a 1-mm diameter drill, coinciding with the natural time of weevil oviposition in the spring. Leaders were removed in the fall, and the bark and xylem from the upper and lower regions of the leader extracted and analyzed by gas chromatography. Unwounded trees had low amounts of resin in xylem compared with bark. In response to wounding, volatile terpenes and diterpene resin acids increased in the upper xylem (area of wounding), with resistant trees showing a greater increase than susceptible trees. Wounding caused monoterpenes in particular to decrease in the lower region of the leader (away from the drilled area) in greater amounts in susceptible trees than in resistant trees. In response to wounding, the proportion of monoterpene to resin acid increased in the upper and lower xylem of resistant trees, and slightly increased in the upper xylem of susceptible trees. Monoterpene-enriched resin is more fluid than constitutive resin, and probably flows more readily into oviposition cavities and larval mines, where it may kill immature weevils. Loss of resin components in the lower xylem suggested catabolism and transport of these materials to the site of wounding; however, energetic and regulatory data are necessary to confirm this hypothesis. This study provides a basis for measuring the ability of a tree to undergo traumatic resinosis that could be used to screen for resistance to white pine weevil.     

Agent-specific responses in the cingulate cortex during economic exchanges

Interactions with other responsive agents lie at the core of all social exchange. During a social exchange with a partner, one fundamental variable that must be computed correctly is who gets credit for a shared outcome; this assignment is crucial for deciding on an optimal level of cooperation that avoids simple exploitation. We carried out an iterated, two-person economic exchange and made simultaneous hemodynamic measurements from each player's brain. These joint measurements revealed agent-specific responses in the social domain ("me" and "not me") arranged in a systematic spatial pattern along the cingulate cortex. This systematic response pattern did not depend on metrical aspects of the exchange, and it disappeared completely in the absence of a responding partner.     

Methicillin-resistant Staphylococcus aureus infections in 11 dogs

Methicillin-resistant Staphylococcus aureus infection was identified in 11 dogs. The infection was associated with surgical treatment especially orthopaedic surgery. Infection after traumatic wounding, and recurrent pyoderma was also seen. Oral antibiotic treatment improved or resolved the infection in nine of the 11 dogs, although the methicillin-resistant isolates were susceptible to relatively few antibiotics.     

Kinetics of Plasma Cell‐Free DNA and Creatine Kinase in a Canine Model of Tissue Injury

Background

Cell‐free DNA (cfDNA) comprises short, double‐stranded circulating DNA sequences released from damaged cells. In people, cfDNA concentrations correlate well with disease severity and tissue damage. No reports are available regarding cfDNA kinetics in dogs.

Objectives/Hypothesis

Cell‐free DNA will have a short biological half‐life and would be able to stratify mild, moderate, and severe tissue injury. Our study aims were to determine the kinetics and biological half‐life of cfDNA and to contrast them with those of creatine kinase (CK).

Animals

Three groups of 10 dogs undergoing open ovariohysterectomy, surgery for cranial cruciate ligament rupture (CCLR), or hemilaminectomy.

Methods

Plasma for cfDNA and CK analysis was collected at admission, at induction of anesthesia, postsurgery (time 0) and at 6, 12, 24, 36, 48, 60, and 72 hours after surgery.

Results

The biological half‐life of plasma cfDNA and CK were 5.64 hours (95% confidence interval [CI 95], 4.36–7.98 hours) and 28.7 hours (CI95, 25.3–33.3 hours), respectively. In the hemilaminectomy group, cfDNA concentrations differed significantly from admission at 6–12 hours after surgery. Creatine kinase activity differed among the surgical groups and reached a peak 6 hours after surgery. In the ovariohysterectomy and CCLR groups, plasma CK activity 72 hours after surgery did not differ from admission activity of the ovariohysterectomy group. In contrast, in the hemilaminectomy group, plasma CK activity after 72 hours did not return to the ovariohysterectomy group admission activity.

Conclusions and Clinical Importance

Plasma CK activity has a longer biological half‐life than previously thought. In contrast to plasma CK activity, cfDNA has a short half‐life and could be a useful marker for peracute severe tissue injury.     

Histological response of resistant and susceptible white spruce to simulated white pine weevil damage

The traumatic wound response of families of white spruce, Picea glauca (Moench) Voss, resistant or susceptible to the white pine weevil, Pissodes strobi (Peck), were compared after simulated weevil damage. Leaders from 331 trees were wounded just below the apical bud in the spring, coinciding with the natural time of weevil oviposition. A portable 1-mm diameter drill was used to drill 24 holes per leader. Leaders were removed in the fall and examined for evidence of traumatic resin canal formation. Drilled trees had a traumatic wound response 8 times greater than that of undrilled trees; however, undrilled trees also formed some resin canals in response to unknown causes. In the drilled trees, the traumatic wound response extended into the lower part of the leader, where it could possibly affect older larvae. Trees from resistant families responded with greater intensity than trees from susceptible families, by producing multiple rings of traumatic resin canals. Trees from resistant families also responded more rapidly than trees from susceptible families based on number of cells to the first ring of traumatic resin canals. Trees from some resistant families exhibited no traumatic resin canal formation, showing considerable within-family variation and suggesting that other resistance mechanisms might be important. In the year after drilling, there was a reduction in tree diameter growth and trees suffered a reduction in constitutive resin canals in the bark, which suggests some energetic cost of traumatic resin production. There was no indication that the extent of constitutive defenses, as measured by density of cortical resin canals before wounding, was related to the ability to produce traumatic resin canals. Screening trees based on their capacity to produce traumatic resin canals may be useful in selecting genotypes resistant to white pine weevil.     

Faunal effects on the distribution of gamma emitting radionuclides in four forested soils

Brown trouts, Salmo trutta, were exposed via aquarial water to ²⁰³Hg²⁺ or to CH₃ ⁻²⁰³Hg⁺ alone or together with one of the following S-containing substances: sodium dimethyldithiocarbamate (SMC), sodium diethyldithiocarbamate (SEC), potassium ethylxanthate (PEX), sodium isopropylxanthate (SIX), sodium diethyldithiophospbate (SEP), sodium diisopropyldithiophosphate (SIP) or sodium pyridinethione (SPyr). The distribution of the ²⁰³Hg²⁺ and the CH₃−²⁰³Hg⁺ in the fishes were then studied by whole-body autoradiography and gamma spectrometry. The results showed that the examined complexing substances can induce increased uptake of both ²⁰³Hg²⁺ and CH₃−²⁰³Hg⁺ by the fishes: for ²⁰³Hg²⁺ most of the complexing substances induced a similar increase in various tissues; for CH₃−²⁰³Hg⁺ marked variations were seen for different substances. Determinations of chloroform/water partition coefficients showed that the examined substances are able to form lipophilic complexes both with Hg²⁺ and CH₃−Hg⁺. A facilitated penetration of the lipophilic complexes over the membranes of the gills and other tissues may underly the increments of the tissue-levels of the Hg. It is possible that increased uptake of Hg²⁺ and CH₃−Hg⁺ induced by complexing substances of this type may have toxicological implications for fishes and for other aquatic organisms.     

Cyclosporine treatment of anal furunculosis in 26 dogs

OBJECTIVES: To evaluate the effect of cyclosporine on anal furunculosis lesions in 26 dogs. METHODS: Lesions were graded as mild in 11 dogs, moderate in eight and severe in seven. Each dog was treated with approximately 4 mg/kg cyclosporine orally every 12 hours until the lesions resolved or showed no further improvement. Residual lesions were resected surgically. RESULTS: Eighteen dogs (69 per cent) experienced complete resolution, seven (27 per cent) improved but had residual lesions and one (4 per cent) showed no improvement. The mean duration of treatment until resolution or no further improvement was 8.8 weeks (range four to 24 weeks). Nine dogs (35 per cent) experienced recurrence. Six were from the group that had shown complete resolution and three were from the group that had surgery. Fifteen dogs (58 per cent) developed side effects to cyclosporine, although none required treatment to be discontinued. Mean duration of follow-up was 6.8 months (range one to 20 months). CLINICAL SIGNIFICANCE: Cyclosporine was effective at resolving or reducing anal furunculosis lesions in 25 of 26 dogs (96 per cent). However, residual or recurrent lesions remain a potential problem, and surgical resection or long-term cyclosporine treatment may be necessary in some dogs.