Electroencephalography of Detomidine-Ketamine-Halothane and Detomidine-Ketamine-lsoflurane Anesthetized Horses During Orthopedic Surgery A Comparison

This study was done to compare the electroencephalographic (EEG) response evoked by orthopedic surgery in halothane- and isoflurane-anesthetized horses. Eight horses scheduled for bilateral arthroscopic surgery of the stifle were premedicated with detomidine (20 μg/kg) intravenously and five minutes later induced to anesthesia with ketamine (2.2 mg/kg) intravenously. Anesthesia was maintained with either halothane or isoflurane. Assignment of inhalation anesthetic was done randomly. The multiple of minimal alveolar concentration (MAC) of halothane required for anesthesia was significantly higher than the multiple of MAC of isoflurane (p < .05) required. Total amplitude of the EEG with halothane was smaller than with isoflurane (p < .05), but 13.0 to 32.0 Hz high frequency/0.0 to 3.9 Hz low frequency (|3/A) ratio was greater for halothane (p < .05). Arterial partial pressure of oxygen (PaO₂) was significantly (p < .05) higher with isoflurane than with halothane. The differences in EEG frequency shift observed suggest that isoflurane provided better analgesia than halothane for this group of horses.     

RADIOGRAPHICALLY VISUALIZED SKELETAL CHANGES ASSOCIATED WITH MUCOPOLYSACCHARIDOSIS VI IN CATS

The radiographic skeletal form and structure of all cats with mucopolysaccharidosis VI is described. Common manifestations included epiphyseal dysplasia, generalized osteoporosis, abnormal nasal turbinate development, his subluxation, impaired development of skeletal growth, pectus excavatum, hyoid hypoplasia, aplasia, hypoplasia and fragmentation or abnormal ossification of the dens, and aplasia or hypoplasia of frontal and sphenoid sinuses. The skeletal measurements of two affected cats were compared with those of normal, sex-matched littermates, and the measurements of two affected female cats were compared with those of a normal male littermate.     

Systemic and Local Effects Associated With Long-Term Epidural Catheterization and Morphine-Detomidine Administration in Horses

Objective — The purpose of this study was to determine the systemic and local effects associated with long-term epidural catheterization and epidural morphine-detomidine administration in horses. Study Design — Development of systemic or local effects was assessed by placing caudal epidural catheters in study horses and administering injections through the catheters every 12 hours for 14 days. Animals — Ten horses with epidural catheters that received daily injections; six uncatheterized horses presented for euthanasia. Methods — Horses received either 0.2 mg/kg morphine sulfate and 30 μg/kg detomidine hydrochloride or an equivalent volume of physiologic saline solution through epidural catheters. Systemic effects were compared between control and treatment horses by measuring physical parameters and hay and water consumption, as well as by evaluating major organs after euthanasia. Local effects were studied by examining cerebrospinal fluid and by grading representative samples of the spinal cord and surrounding tissues histologically for inflammation and fibrosis. Local effects were compared between control and treatment horses, as well as between catheter-ized (control plus treatment) horses and uncatheterized horses. Results — No significant difference was identified in daily variables or hay and water consumption between control and treatment horses. No growth was obtained from cerebrospinal fluid cultures. No significant difference in cerebrospinal fluid values or spinal tissue inflammation or fibrosis grades was shown between control and treatment horses. However, when compared with uncatheterized horses, cerebrospinal fluid red blood cell values were marginally higher and protein concentrations were significantly higher in the catheterized group. Lumbosacral and sacral spinal tissue segment inflammation grades, and sacral segment fibrosis grades were significantly higher in catheterized horses. Conclusions — Long-term epidural administration of a morphine-detomidine combination is not associated with apparent adverse systemic effects in horses. Localized inflammation and fibrosis seem to be catheter-related. Clinical Relevance — Potential systemic and local effects are important considerations with long-term administration of a morphine-detomidine combination through indwelling epidural catheters for alleviation of chronic musculoskeletal pain in horses.     

Subepidermal bullous dermatosis due to topical corticosteroid therapy in dogs

Six adult dogs were presented with an unusual bullous dermatosis affecting the glabrous skin of the ventral abdomen and medial thighs. Clinically, flaccid bullae were accompanied by erythema, ulceration, haemorrhage and hyperpigmentation in four of six dogs; the remaining two dogs had thin skin without grossly apparent bullae. Histologically, subepidermal bullae and clefting, vascular proliferation and dilatation (phlebectasia), and alteration in the density and staining of superficial dermal collagen were seen in all dogs. In all cases, corticosteroid-containing topical products had been applied to the affected areas prior to the development of the dermatosis; skin lesions resolved when topical corticosteroids were withdrawn. Follow-up biopsy of three dogs showed resolution of the previously abnormal collagen and subepidermal clefting. Residual lesions included phlebectasia, comedones and hyperpigmentation. The authors postulate that subepidermal clefting was due to local, corticosteroid-induced skin fragility. This is the first report, to our knowledge, of bullous skin disease in dogs resulting from topical corticosteroid therapy.     

EFFECTS OF WATERSHED LIMING ON PICEA RUBENS SEEDLING BIOMASS AND NUTRIENT ELEMENT CONCENTRATION

Effects of watershed liming on the biomass and tissue chemistry of planted Picea rubens Sarg. (red spruce) seedlings were investigated for two growing seasons after two subcatchments in a forested Adirondack, New York (U.S.A.) watershed were limed aerially with 6.89 t ha^-1 of calcitic limestone (CaCO₃). Picea rubens has been the focus of numerous atmospheric deposition research studies, but less well investigated for responses to amelioration. Picea rubens seedlings were planted in limed and reference subcatchments and harvested the first and second growing season after liming to measure total, foliar, and stem (i.e., branch) biomass, and concentrations of Ca, Mg, K, Al, Na, and P in the annual growth increment of foliage and branches. In the second year after liming, both foliage and stem biomass of seedlings from reference plots were at least 50% greater than seedling biomass from limed plots. Seedlings in limed areas had significantly greater foliar concentrations of Mg and P in the first year after liming, but not in the second year. Foliar Ca was not significantly different in limed than reference seedlings. Foliar Al concentrations were greater in reference than limed seedlings, but still below documented toxicity levels. Stem concentrations of Mg, K, and P in seedlings from limed areas decreased significantly between the first and second growing season after liming, while reference seedling stem concentrations either increased or declined only slightly. Correlations among foliar nutrients and foliar biomass from limed plots were negative and suggest an inverse dilution effect. Foliar Al concentrations were negatively correlated with Ca, Mg, K, and P in seedlings from reference plots, but positively correlated in limed plots. The adverse response of P. rubens seedlings to lime may reflect changes in nutrient availability associated with changes in soil pH.     

Marine environment‐based forecasting of coho salmon (Oncorhynchus kisutch) adult recruitment

Generalized additive models (GAMs) were used to investigate the relationships between annual recruitment of natural coho salmon (Oncorhynchus kisutch) from Oregon coastal rivers and indices of the physical ocean environment. Nine indices were examined, ranging from large‐scale ocean indicators, e.g., Pacific Decadal Oscillation (PDO), to indicators of the local ecosystem (e.g., coastal water temperature near Charleston, OR). Generalized additive models with two and three predictor variables were evaluated using a set of performance metrics aimed at quantifying model skill in short‐term (approximately 1 yr) forecasting. High explanatory power and promising forecast skill resulted when the spring/summer PDO averaged over the 4 yr prior to the return year was used to explain a low‐frequency (multi‐year) pattern in recruitment and one or two additional variables accounted for year‐to‐year deviations from the low‐frequency pattern. More variance was explained when averaging the predictions from a set of models (i.e., taking the ensemble mean) than by any single model. Making multiple forecasts from a set of models also provided a range of possible outcomes that reflected, to some degree, the uncertainty in our understanding of how salmon productivity is driven by physical ocean conditions.     

Resection of a Large Intra‐Abdominal Tumor in the Mexican Axolotl: A Case Report

Objective— This case report describes the surgical removal of an intra‐abdominal tumor from a Mexican axolotl (Ambystoma mexicanum). The animal was admitted with left abdominal swelling that had increased over 4 months. Methods— Surgical removal was performed under general anesthesia with MS222 under an operating microscope. Exploratory laparotomy was performed through 2.5 dorsocranial skin incision in the left flank, followed by subcutaneous dissection. Results— The tumor involved the spleen, was adjacent to the descending colon, and supplied by vessels from the spleen, stomach, and colon. The mass was removed by clamping and transecting the spleen and the peritoneum was closed with a continuous suture pattern, while abdominal muscles and skin were closed in layers. After a total duration time of anesthesia of 90 minutes the animal was kept in prophylactic antibiotic baths. Tissue sections revealed characteristics of both lymphangiosarcoma and lymphosarcoma with an appearance typical for a malignant tumor. Conclusions— Abdominal surgery was performed in an axolotl and the surgical wound healed without complication.     

EFFECT OF HEAD AND NECK POSITION ON PHARYNGEAL DIAMETER IN HORSES

Dynamic nasopharyngeal collapse with upper airway obstruction is an important cause of exercise intolerance in performance horses. Its underlying pathophysiology is not fully understood. We hypothesize that head position affects pharyngeal diameter, and thus head position may be a contributing factor to nasopharyngeal obstruction. Fifteen adult healthy horses were subjected to endoscopy and radiography at rest. The pharyngeal diameter was measured at nine different head and neck positions. The effect of sedation and breathing cycle on the pharyngeal diameter was determined, and the relationship between the head angle and the pharyngeal diameter was analyzed. There was a significant influence of head and neck position on pharyngeal diameter, with head position having the major effect (P<0.001); neck position was less important, but still significant (P<0.05). The smallest pharyngeal diameter was found at the dorsal, flexed position, which is a clinically important head position in dressage horses. The largest pharyngeal diameter was found at the extended midway position. At each head level, the pharyngeal diameter decreased with flexing the head and it increased with extending the head. The head angle was not associated with pharyngeal diameter, and neither sedation status nor breathing cycle significantly affected pharyngeal diameter. A decrease in pharyngeal diameter will limit the airflow through the upper respiratory tract, and it may result in turbulence with subsequent dynamic collapse. Head and neck position should therefore be considered a possible contributing factor in horses with suspected nasopharyngeal dysfunction.     

Impact of wind stress anomalies on the seasonal pattern of southern rock lobster (Jasus edwardsii) settlement in South Australia

Quantified estimates of southern rock lobster (Jasus edwardii) puerulus settlement have been undertaken in the Southern Zone fishery of South Australia since the early 1990s. An analysis of mean monthly puerulus settlement indices from 1995 to 2007 in three monitoring sites revealed a strong seasonal correlation (r > 0.94 between sites) in settlement patterns. Settlement was highest during the winter months of June, July and August with peak settlement in all sites occurring in July. A reduced secondary settlement occurred during February and March. Seasonal trends were correlated with monthly wind stress and direction data in order to investigate possible environmental drivers of settlement. Using monthly averages of wind stress, it was hypothesized that strong along‐shore wind‐stress anomalies (ASWSA) prior to peak settlement would influence puerulus indices. Maximum ASWSA over the December–May period prior to maximum settlement was therefore examined. The results showed significant correlations (P < 0.1, r = 0.51–0.90) between wind stress and puerulus settlement in all but one site. We suggest that storm events, in combination with onshore surface drift during the period of settlement, are the principal physical oceanographic mechanisms influencing settlement patterns within the Southern Zone rock lobster fishery of South Australia.