Characterizing structural conditions in mature managed red pine: Spatial dependency of metrics and adequacy of plot size

Restoration of the range of forest types and stages that once composed the landscape mosaic of the Upper Great Lakes region of North America will involve manipulating managed red pine stands to recreate now rare structural conditions. Because many of the attributes used to characterize structural condition depend upon spatial arrangement, sampling schemes to assess condition must match sampling extent to attribute variability. To evaluate the metrics and scales appropriate for characterizing structural complexity in managed red pine, we applied metrics that incorporated one-, two-, and three-dimensional structural attributes to eight 1.0 ha mature stem-mapped stands. Most metrics were also calculated within simulated moving windows of 0.05–1.0 ha in sampling extent (“plot size”) within each stand. Two standards were used to evaluate the adequacy of plot sizes for these metrics: (1) estimates were precise, varying less than 10% among moving windows for a given scale, and (2) estimates were accurate to within 10% of the 1.0 ha value at both the 5th and 95th percentiles of the moving window distributions. Necessary sample sizes to achieve precise and accurate estimates were also calculated for each scale.     

Organogenesis and foetal haemodynamics during the normal gestation of healthy black‐rumped agoutis (Dasyprocta prymnolopha,Wagler, 1831) bred in captivity

The objective of this study was to define the patterns of organogenesis and foetal haemodynamics during the normal gestation of healthy agoutis (Dasyprocta prymnolopha) kept in captivity. Thirty pregnant agoutis that ranged in size from small to medium and weighed between 2.5 and 3 kg underwent B‐mode and Doppler ultrasonography for the biometric evaluation of the foetal organs. The foetal aortic blood flow proved to be predominantly systolic, and the measured flow velocity was 78.89 ± 2.95 cm/s, with a maximum pressure gradient of 2.12 ± 0.27 mmHg. The liver was characterized by its large volume, occupying the entire cranial aspect of the abdominal cavity, and it was associated cranially with the diaphragm and caudally with the stomach. The flow velocity in the portal vein was estimated to equal 12.17 ± 2.37 cm/s, with a resistivity index of 0.82 ± 0.05. The gallbladder was centrally located and protruded cranially towards the diaphragm. The spleen was visualized as an elongated structure with tapered cranial and caudal extremities, and the foetal kidneys were visualized bilaterally in the retroperitoneal region, with the right kidney positioned slightly more cranially than the left. The morphological characterization and hemodynamic analysis of the foetal organs of black‐rumped agoutis via B‐mode and Doppler ultrasonography allow determination of the vascular network and of reference values for the blood flow required for perfusing the anatomical elements essential for maintaining the viability of foetuses at different gestational ages.     

Radiographic Evaluation of the Anconeal Process in Skeletally Immature Dogs

Objective: To determine if a secondary center of ossification (SCO) of the anconeal process is present in skeletally immature dogs that do not develop an ununited anconeal process (UAP). Study Design: Case series. Animals: Dogs 77–154 days of age with conditions other than developmental disease of the elbow (n=78 dogs; total elbows=100). Methods: Mediolateral radiographic projections of the elbow were reviewed for presence or absence of a SCO of the anconeal process. Results: A SCO was radiographically evident in 16% of elbows from breeds that have been reported to be affected by UAP. The appearance of the SCO was different to an UAP fragment. None of the elbows with SCO of the anconeal process developed UAP. A SCO was not present in any small breed dogs. Conclusions: A SCO of the anconeal process is uncommon in medium and large breed dogs and the presence of a SCO does not indicate that UAP will develop. Clinical Relevance: Because radiographic diagnosis of a SCO of the anconeal process and UAP lesions have distinct appearances, an earlier diagnosis of UAP is possible.     

Modeling the effects of temperature on the survival and growth of North Sea cod (Gadus morhua) through the first year of life

Temperature and body size are widely agreed to be the primary factors influencing vital rates (e.g., growth, mortality) in marine fishes. We created a biophysical individual‐based model which included the effects of body size and temperature on development, growth and mortality rates of eggs, larvae and juveniles of Atlantic cod (Gadus morhua L.) in the North Sea. Temperature‐dependent mortality rates in our model were based on the consumption rate of predators of cod early‐life stages. The model predicted 35%, 53% and 12% of the total mortality to occur during the egg, larval and juvenile stages, respectively. A comparison of modeled and observed body size suggested that the growth of survivors through their first year of life is high and close to the growth rates in ad libitum feeding laboratory experiments. Furthermore, our model indicates that experiencing warmer temperatures during early life only benefits young cod (or theoretically any organism) if a high ratio exists between the temperature coefficients for the rate of growth and the rate of mortality. During the egg stage of cod, any benefit of developing more rapidly at warmer temperatures is largely counteracted by temperature‐dependent increases in predation pressure. In contrast, juvenile (age‐0) cod experiences a higher cumulative mortality at warmer temperatures in the North Sea. Thus, our study adds a new aspect to the ‘growth–survival’ hypothesis: faster growth is not always profitable for early‐life stages particularly if it is caused by warmer temperatures.     

Evidence for endogenous opioid modulation of serum luteinizing hormone and prolactin in the steer

Opioid modulation of LH and prolactin (PRL) concentrations in Angus steers was investigated. In Exp. 1, morphine sulfate (M) was administered at either 1, 2 or 3 mg/kg BW (n = 4) as an i.v. injection. Blood samples were obtained at 15-min intervals for 4 h pre- and post-treatment for serum hormone analyses. Mean serum LH concentration and number of LH secretory pulses decreased (P less than .1) for 2 h after M (4.1 to nadir of 2.4 ng/ml, and .33 vs. .21 pulses/h; pre- vs post-treatment). Luteinizing hormone pulse amplitude decreased (P less than .01; 7.3 vs 2.6 ng/ml; pre- vs post-treatment) during the 2 h following M. Prolactin concentrations increased 126.6%, 170.6% and 187.6% following 1, 2 and 3 mg M/kg BW, respectively (P less than .05, 1 vs 2; P less than .01, 1 vs 3). In Exp. 2, either saline solution (S, n = 6) or M (.31 mg/kg BW, i.v. injection followed by .15 mg/(kg.h) infusion; n = 6) was given for 7 h. Concentration of LH was unaffected. Response of LH to naloxone was determined in Exp. 3. Blood samples were obtained for 2 h pre- and post-administration of either naloxone (1 mg/kg BW, i.v. injection; n = 5) or S (n = 5). Response of LH at 15, 30 and 45 min posttreatment was greater (P less than .05) in naloxone- compared with S-treated steers. In summary, M had no significant effect on serum LH concentration or LH pulse frequency, but it decreased pulse amplitude and increased serum PRL concentrations. In contrast, naloxone increased LH secretion. These observations taken together indicate a physiological role for opioid modulation of LH and PRL secretion in the steer.     

Effect of morphine on serum gonadotropin concentrations in postpartum beef cows

Morphine (M), an opioid agonist, was administered to postpartum (PP) Angus cows to investigate opioid modulation of gonadotropin secretion. In Exp. 1, eight PP cows (36.9 +/- 2.3 d) received either M (1 mg/kg; n = 4) or saline solution (S) (n = 4) via i.v. injection 36 h after calf removal. Morphine decreased (P less than .01) the number of serum LH pulses (3.0 +/- 1.1 pre- vs .3 +/- .3 post-pulses/h) and, compared with pretreatment values (3.3 mg/ml), decreased (P less than .05) mean LH at 105 min (2.1 ng/ml) through 270 min 1.9 ng/ml +/- .4). Serum prolactin (PRL) increased (P less than .01) following M from 16.4 ng/ml to a peak of 59.3 ng/ml (+/- 3.9). Serum FSH concentrations were unaffected. In Exp. 2, M (.31 mg/kg i.v. injection followed by .15 mg/(kg.h) infusion; n = 6) or S (n = 6) treatments were given for 7 h beginning 36 h after calf removal. Serum LH was similar between groups during the pretreatment and the first 6 h of infusion, but M decreased (P less than .001) the number of serum LH pulses (.44 +/- .09 vs .06 +/- .04 pulses/h). Morphine increased (P less than .05) serum PRL. It is concluded that M differentially modulated gonadotropin secretion in the cow such that PRL increased, LH decreased and FSH was unchanged.     

An effective buprenorphine analgesic protocol increases post-operative adhesions in rats after laparotomy

The use of analgesics in post‐operative adhesion (POA) research is problematic due to POA‐inhibiting effects of anti‐inflammatory agents and bowel motility‐inhibiting effects of opioids, which may increase adhesion formation. This study was conducted to assess a buprenorphine (BUP) protocol for analgesic efficacy and its effects on POA formation in a rat cecal abrasion model. The protocol was approved by the University of Florida's Institutional Animal Care and Use Committee (IACUC). Forty‐one female Sprague‐Dawley rats were randomized into two groups (n = 20 or 21 group). Body weight, food and water intake were recorded daily from 2 days before until 7 days after surgery. Treatment rats received 0.05 mg kg^–1 BUP SQ at anesthesia induction and 0.3 mg kg^–1 BUP orally in flavored gelatin 6 hours after surgery. Control rats received saline placebo injection and plain gelatin. All rats underwent laparotomy and controlled cecal abrasion. At 3, 6 and 24 hours post‐operatively rats were individually observed in 10‐minutes periods for pain related behavior incidence: ‘twitch’ (contraction of muscles along dorsum and/or head), ‘back arch’ (cat‐like position with front legs extended and pushing backward), ‘writhe’ (flank contraction), and ‘stagger/fall’ (momentary loss of balance while grooming or ambulating), using the method of Roughan and Flecknell (Pain 2001,90, 65–74). On post‐op day seven rats were euthanized by CO₂ inhalation and POA evaluated (0 to 4 scale; ³Grade 2 = clinically significant.) BUP treated rats had lower mean pain scores than control rats at 3 hours (1.6 ± 1.7 versus 20.3 ± 13.5 (mean ± SD); p < 0.001) and 6 hours (2.1 ± 2.7 versus 23.7 ± 12.9; p < 0.001) but not 24 hours (1.5 ± 1.3 versus 4.9 ± 6.6; p = 0.35) post‐operatively. Predominant pain behavior was ‘writhe’ (flank contraction) in contrast to ‘twitch,’‘back arch,’ and ‘stagger/fall’ reported as most common pain indicators in other rat strains. BUP rats had greater mean adhesion incidence (2.4 ± 1.7 versus 1.4 ± 1.8; p < 0.03) and severity (90%³Gr.2 versus 65% of controls; p < 0.05). The BUP protocol appeared to provide effective analgesia for at least 24 hours post‐operatively. Strain of rat may affect pain related behavior. BUP should be used with caution after abdominal surgical procedures having high risk of POA formation.     

Pharmacokinetics of sulfamethoxazole and trimethoprim in donkeys, mules, and horses

OBJECTIVE: To compare serum disposition of sulfamethoxazole and trimethoprim after IV administration to donkeys, mules, and horses. ANIMALS: 5 donkeys, 5 mules, and 3 horses. PROCEDURE: Blood samples were collected before (time 0) and 5, 15, 30, and 45 minutes and 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, and 24 hours after IV administration of sulfamethoxazole (12.5 mg/kg) and trimethoprim (2.5 mg/kg). Serum was analyzed in triplicate with high-performance liquid chromatography for determination of sulfamethoxazole and trimethoprim concentrations. Serum concentration-time curve for each animal was analyzed separately to estimate noncompartmental pharmacokinetic variables. RESULTS: Clearance of trimethoprim and sulfamethoxazole in donkeys was significantly faster than in mules or horses. In donkeys, mean residence time (MRT) of sulfamethoxazole (2.5 hours) was less than half the MRT in mules (6.2 hours); MRT of trimethoprim in donkeys (0.8 hours) was half that in horses (1.5 hours). Volume of distribution at steady state (Vdss) for sulfamethoxazole did not differ, but Vdss of trimethoprim was significantly greater in horses than mules or donkeys. Area under the curve for sulfamethoxazole and trimethoprim was higher in mules than in horses or donkeys. CONCLUSIONS AND CLINICAL RELEVANCE: Dosing intervals for IV administration of trimethoprim-sulfamethoxazole in horses may not be appropriate for use in donkeys or mules. Donkeys eliminate the drugs rapidly, compared with horses. Ratios of trimethoprim and sulfamethoxazole optimum for antibacterial activity are maintained for only a short duration in horses, donkeys, and mules.