Esophageal Replacement in the Dog by Microvascular Colon Transfer

An orthotopic colon graft based on the middle colic artery and vein was implanted with microvascular technique and a stapling instrument in five dogs. The grafts were successful in four dogs. A similar colon autograft was used to replace the entire thoracic esophagus in five dogs. The recipient vessels were the left carotid artery and left external jugular vein. Four of the grafts failed because of kinking and thrombosis of the arterial supply (2 dogs) or the venous outflow (2 dogs). One graft, which had a viable vascular supply, developed a severe leak at the colon-to-stomach anastomosis, and the dog was euthanatized on day 3. The recipient vascular pedicle was modified and used successfully to replace a portion of the cervical esophagus in three dogs. The grafts survived, the dogs could swallow liquids and semisolid food well, and, at necropsy after 4 weeks, the anastomotic sites were well healed. The graft sites contained essentially normal colon mucosa.     

Some Effects of the Plantation of Conifers on a Freely Drained Lowland Soil, Forest of Dean, U.K.

Acid brown soils under 50-year-old conifer plantations are comparedwith those at a control site under the previous vegetation ofmixed deciduous woodland. The soils under the conifers showsignificant signs of podzolization and associated with this,evidence of structural breakdown. The implications of thesechanges are briefly discussed.     

The Effect of Starch Amendment on Nitrogen Mineralisation from the Forest Floor Beneath a Range of Conifers

Samples of LFH collected beneath the canopies of 16 coniferousspecies growing at the same site were incubated in the laboratorywith or without a starch amendment. Exchangeable nitrogen presentranged from 10.5–256 and 11.4–512 µgg^–1organic matter for freshly collected and unamended incubationsrespectively. When starch was added material from 11 speciesshowed significantly greater accumulation of mineral nitrogenwith increases ranging from ca 20–1370 per cent. Nitrificationwas negligible except in Thuja plicata where nitrate constituted68 or 83 per cent of the mineral nitrogen present after incubationwithout or with starch respectively. Starch addition increasedrates of net nitrogen mineralisation in LFH material from Piceasitchensis over a range of growth rates. Rates were greatestin material from the most productive stands whether or not starchwas added. The results are discussed with reference to the factorscontrolling litter decomposition and nitrogen mineralisationin the forest floor.     

Influences of mean advection and simple behavior on the distribution of cod and haddock early life stages on Georges Bank

Results of a modeling study designed to explore the influences of physical advection and certain biological mechanisms on the distribution of cod (Gadus morhua) and haddock (Melarwgrammus aeglefinus) early life stages on Georges Bank are described. Using a late-winter/early-spring 3-D circulation field driven by the M₂ tidal current, mean wind stress and Scotian Shelf inflow, we examine the distribution of cod and haddock larvae spawned on the Northeast Peak of the Bank. The sensitivity to a March-April baroclinic field is also explored. Results indicate that larvae remaining in the surface Ekman layer are generally advected off-bank. However, downwelling associated with Ekman layer convergence near the shelf break provides a mechanism for larvae to exit from the off-bank surface drift. Larvae below the surface layer are transported south-westward along the southern flank of Georges Bank and are retained on the Bank if their position immediately upstream of the Great South Channel is shoalward of (roughly) the 70 m isobath. Within the Great South Channel region and between the 50 and 70 m isobaths, retention can depend on the phase of the tide. Spawning shoalward of the 50 m isobath on the Northeast Peak greatly increases the chances of retention. These results apply to passive larvae and to those with specified vertical distributions and migration based on observations. Directional on-bank swimming at rates of 0.5 to 1 body length per second would substantially enhance shoalward displacement, resulting in larval distributions during the first 2 months that are consistent with field observations.     

Sampling error resulting from depth-dependent plankton distributions and current differentials in a two-layered system

We evaluate a source of error observed in standard ichthyoplankton bongo tows in which volumes of water filtered did not result in increased catches of red-fish. Our analyses demonstrate that, under conditions where redfish larvae are distributed in surface waters in a two-layered system, current differentials between surface and subsurface layers resulted in biased, standardized estimates of larval abundances as a result of filtering varying amounts of subsurface waters. Analysis of standard survey results on Flemish Cap demonstrated that this source of bias was limited to the May-June period, after waters became stratified and before redfish passed from the larvae to pelagic juvenile stage. Correcting for this source of sampling bias wIII result in more accurate absolute estimates of ichthyoplankton abundance, and we estimate that variation (CV) for replicate samples may be reduced by 10%.     

RADIOGRAPHIC EVALUATION OF FELINE APPENDICULAR DEGENERATIVE JOINT DISEASE VS. MACROSCOPIC APPEARANCE OF ARTICULAR CARTILAGE

Degenerative joint disease (DJD) is common in domesticated cats. Our purpose was to describe how radiographic findings thought to indicate feline DJD relate to macroscopic cartilage degeneration in appendicular joints. Thirty adult cats euthanized for reasons unrelated to this study were evaluated. Orthogonal digital radiographs of the elbow, tarsus, stifle, and coxofemoral joints were evaluated for the presence of DJD. The same joints were dissected for visual inspection of changes indicative of DJD and macroscopic cartilage damage was graded using a Total Cartilage Damage Score. When considering all joints, there was statistically significant fair correlation between cartilage damage and the presence of osteophytes and joint‐associated mineralizations, and the subjective radiographic DJD score. Most correlations were statistically significant when looking at the different joints individually, but only the correlation between the presence of osteophytes and the subjective radiographic DJD score with the presence of cartilage damage in the elbow and coxofemoral joints had a value above 0.4 (moderate correlation). The joints most likely to have cartilage damage without radiographic evidence of DJD are the stifle (71% of radiographically normal joints) followed by the coxofemoral joint (57%), elbow (57%), and tarsal joint (46%). Our data support radiographic findings not relating well to cartilage degeneration, and that other modalities should be evaluated to aid in making a diagnosis of feline DJD.