The effect of seed pretreatment and sowing date on the nursery emergence of Sitka spruce (Picea sitchensis [Bong.] Carr.) seedlings

Sitka spruce seeds which had been: (1) untreated (U), (2) prechilled(P), or (3) prechilled and then redried and stored for 16 months(R), were sown into progressively warmer seed beds on four datesat monthly intervals from March to June. At each sowing date,samples of seed were germinated in the laboratory at optimum(20°C) and sub-optimum (10°C) temperatures. Prechillingand prechilling + redrying both increased the rate and totalamount of germination compared with untreated seed at each testtemperature. However in the nursery, the beneficial effectsof pretreating Sitka spruce seed were restricted to sowing inMarch and April when soil temperatures were sub-optimal forthe germination of untreated seeds. Pretreatment resulted inrapid seedling emergence at soil temperatures between 10°Cand 15°C, whereas untreated seed germinated slowly and seedlingemergence continued until high soil temperatures in June killedungerminated seeds. The pattern of seedling emergence from theredried seed was similar to that from the prechilled seed, exceptfor a lag in the start of seedling emergence probably due tothe extra time needed for redried seed to imbibe water in theseed beds. Thus redrying caused insignificant loss of seed performanceon the nursery. Seed sown in May and June experienced average temperatures closeto the optimum for germination of 20°C, however daily maximaregularly exceeded 35°C resulting in the cessation of seedlingemergence in all three seed treatments, and the loss of newlyemerged seedlings. Periods of warm weather from June onwardswere the main factors limiting the final number and size ofseedlings.     

THE STORAGE OF ACORNS IN WATER

Acorns of sessile oak (Quercus petraea) will not tolerate prolongedsubmergence, but those of pedunculate oak (Quercus robur) survivevery well in regularly changed distilled water or tap-water.Survival is considerably worse in basic river water; the differencefrom tap-water is likely to be due either to the greater activityof organisms promoting decay, or to the prevalence of loweroxygen-tensions in river water. Storage in water under suitablycontrolled conditions might be a useful practical procedurewith pedunculate acorns.     

Trivalent metal (Cr, Y, Rh, La, Pr, Gd) sorption in two acid soils and its consequences for bioremediation

The recent addition of trivalent metals to soil and their subsequent movement within the biosphere are of concern. For this reason, the sorption of chromium (Cr), yttrium (Y). rhodium (Rh), lanthanum (La), praseodymium (Pr) and gadolinium (Gd) in two contrasting acid soils has been determined. Except for Rh, the sorption of the other trivalent metals conformed well to the Langmuir equation with derived sorption parameters similar for all the trivalent species tested. Calculation of the buffer powers indicated that under both small (0·01 mmol kg^?1) and large (1 mmol kg^?1) trivalent metal soil loadings > 99·5% of the metals will be associated with the exchange phase with small quantities present in the bulk soil solution (<0·5%). It seems that the slight availability of metals within the bulk soil solution will slow the rate of trivalent metal bioremediation of contaminated sites.     

Enhancement of transdermal delivery of phenylbutazone from liposomal gel formulations through deer skin

Phenylbutazone (PBZ) is a nonsteroidal anti‐inflammatory drug used in the treatment of chronic pain and arthritis. Topical and transdermal administration of PBZ would be beneficial in large animals in terms of minimizing gastro‐intestinal ulcerations and other side effects, easy administration to legs and joints and minimizing the dose to reduce systemic toxicity of the drug. A topical liposomal preparation with different concentrations of a mono‐substituted alkyl amide (MSA) and PBZ was formulated. The formulations were evaluated by in vitro skin‐permeation kinetics through deer skin using Franz diffusion cells. By increasing drug loading from 1% to 5% w/w, the steady‐state flux (μg/cm²/h) of PBZ was increased twofold (P < 0.001). Similarly, by increasing the MSA concentration from 0% to 4%, the steady‐state flux (μg/cm²/h) of PBZ was increased twofold (P < 0.001). Overall, by increasing the drug load and the use of an appropriate amount of the penetration enhancer, the steady‐state flux of PBZ through skin was increased fourfold (P < 0.001). MSA at both 2% and 4% w/w concentrations significantly increased the skin levels of PBZ as compared with control (P < 0.05). In conclusion, MSA served as an effective skin‐penetration enhancer in the liposomal gel of PBZ for deer.     

SENSITIVITY OF LOW‐FIELD T2* IMAGES FOR DETECTING THE PRESENCE AND SEVERITY OF HISTOPATHOLOGIC MENISCAL LESIONS IN DOGS

The sensitivity of low‐field magnetic resonance (MR) T2^* images for predicting the presence of meniscal lesions was determined in 12 dogs with naturally‐occurring cranial cruciate ligament rupture and three control dogs, using histopathology as the reference standard. Previously published grading systems were used to grade the severity of meniscal lesions on MR images, gross inspection and histopathology. Focal areas of increased signal intensity were detected in 11/12 symptomatic dogs and 3/3 control dogs. Lesions mimicking meniscal tears (pseudotears) were identified at junctions between meniscal margins and adjacent connective tissue in control dogs and dogs with naturally occurring disease. Histopathologic lesions were present in all menisci of both symptomatic and control dogs, including the menisci from two affected dogs that appeared grossly normal but were removed and submitted based on MR imaging findings. Histopathologic lesions identified included hyaline cartilage metaplasia and changes in the amount of ground substance and cellularity. The sensitivity of MR imaging for detecting the presence of meniscal histopathologic lesions was 90% in symptomatic dogs and 91% in control dogs. However, agreement between severity scores for the different tests was poor. Low‐field MR imaging is a sensitive test for predicting the presence but not severity of meniscal histopathologic lesions in dogs with naturally‐occurring cranial cruciate ligament rupture. Findings also supported previous studies indicating that histopathologic lesions can be present in dogs with grossly normal menisci. An improved grading system for comparing MR images and histopathologic severity of meniscal lesions in dogs is needed.     

The effect of drying techniques on formononetin concentration in red clover

Oven-drying at 60°, 80° or 105°C was compared with microwave and freeze-drying as a method of preparing samples for the estimation of formononetin, the major oestrogenic factor in red clover. There was no significant difference in the formononetin concentration of clover samples either oven-dried at 60°C or freeze-dried. The formononetin concentration was reduced by drying at higher temperatures and by microwave-drying but was not affected by wilting for up to 8 h after harvesting. The routine determination of formononetin in ten varieties of red clover showed no significant differences between samples cold stored at – 18°C prior to oven-drying at 60°C and samples freeze-dried.     

Evaluation of Percutaneous Gastrostomy as a Technique for Permanent Gastropexy

Objective- This study was designed to evaluate right-sided percutaneous endoscopic gastrostomy (PEG) as a method for creation of a permanent gastropexy.
Study Design- Percutaneous endoscopic gastrostomy adhesions were evaluated by gross examination and by mechanical testing and the results were compared with those obtained by conventional incisional gastropexy.
Animals or Sample Population- Fourteen mixed-breed dogs.
Methods- Incisional gastropexies were performed on the dogs of group one (N = 7) and PEG tubes were placed in the dogs of group 2 (N = 7). All skin sutures (group 1) and PEG tubes (group 2) were removed on day 14. The animals were maintained for an additional 44 days before euthanasia and immediate necropsy. Gastropexy adhesions were evaluated and collected for biomechanical evaluation using a materials testing machine.
Results- The duration of the procedure for group 2 was less (32.86 min ±7.65) than for group 1 (56.29 min ±8.28). The number of complications was not significantly different between group 1 and group 2 ( P =.103). Gastroperitoneal adhesions were present in 7 of 7 dogs in group 1 and 4 of 7 dogs in group 2. The adhesion lengths and widths were significantly larger in dogs in group 1 compared with those in group 2. The adhesions present in group 1 dogs sustained significantly greater tensile loads to failure (61.98 ±14.65 N), compared with the adhesions present in group 2 dogs (22.31 ±26.87 N).
Conclusions- Right-sided PEG inconsistently formed a weak gastropexy and the procedure was associated with a trend toward greater morbidity than incisional gastropexy.
Clinical Relevance- Right-sided PEG is not recommended as a means of prophylactic gastropexy.