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OBJECTIVE To evaluate the relationship in equine practice between the time delay for charge entry (time between when work was performed and when the invoice charges were entered) and the total amount of the invoice. SAMPLE A total of 67,597 invoices from 3 hospitals were included for analysis. METHODS Analysis of 67,597 invoices from 49 doctors working out of 3 hospitals was performed. Variables collected included invoice total, date of work, date of invoice entry, month of work, invoice category (A = ambulatory daytime, E = after-hours, 1 = hospital), and veterinarian. Time delay to invoice entry was the difference between the day of work and the day of charge entry. A generalized additive model was used to describe the relationship between the time delay for invoice entry and the invoice type, month of work, and invoice category. The best model was selected using the Akaike information criterion. RESULTS In the selected model, total invoice amount was associated with time delay for charge entry and invoice category. Invoices entered on the same day of work were 299 + $345, as compared to those entered the next day (255 + $271) and those entered > 1 day after the work was performed (193 + $196; P < .0001). CLINICAL RELEVANCE If the observed relationship between time delay (time between work performed and invoice entry) and total invoice amount is causal, equine practitioners may have significant opportunity to improve revenues by simply entering charges on the same day the work is performed. [ABSTRACT FROM AUTHOR]

Background: The addition of calcium to resuscitation fluids is a common practice in horses, but studies evaluating the effects of calcium supplementation are limited. In healthy horses, decreases in heart rate and changes in serum electrolyte concentrations have been reported. Hypothesis: Calcium gluconate administration at a rate of 0.4 mg/kg/min to eliminated endurance horses with metabolic problems will affect heart rate, gastrointestinal sounds, and serum electrolyte concentrations. Animals: Endurance horses eliminated from the Tevis Cup 100‐mile (160 km) endurance ride for metabolic problems and requiring IV fluid therapy were eligible. Methods: Sixteen horses were randomly assigned to receive 0.4 mg/kg/min of calcium (23% calcium gluconate solution) over 1 hour diluted in 10 L of a non‐calcium containing isotonic crystalloid (CAL group) or 10 L of a non‐calcium containing isotonic crystalloid (CON group). Staff members administering the fluids were blinded to treatment group. Blood samples were collected and physical examinations performed before and after treatment. Heart rates were recorded every 15 min during fluid administration. Data were compared using 2‐way analysis of variance (ANOVA) with repeated measures for continuous variables and Fisher's exact test for categorical variables. Results: Calcium was associated with lower heart rates 45 min after starting the infusion (P =.002). Gastrointestinal sounds were less likely to improve in the calcium group compared with the control group (P =.005). An increase in plasma phosphorus concentration (P =.03) was associated with calcium administration. Conclusions: Intravenous calcium supplementation to endurance horses eliminated from competition after development of metabolic problems may decrease heart rate but impairs improvement in gastrointestinal sounds. [ABSTRACT FROM AUTHOR]

OBJECTIVE To evaluate changes in electrolyte concentrations and hydration status that take place in endurance horses prior to the start of a competition and determine whether these changes would be associated with elimination. ANIMALS 19 horses entered in the 2016 Tevis Cup 100-Miles (160 km) One-Day Western States Trail Ride. PROCEDURES Heparinized blood samples were collected at 5 time points: prior to transport to the ride (TO), during check-in the day before the ride (TI), 1 to 2 hours before the start of the ride (TZ), at the 15-km mark (T3), and at the 55-km mark (T4). Packed cell volume and plasma sodium, potassium, chloride, urea nitrogen, glucose, bicarbonate, and total protein concentrations were determined and compared across time points and between finishers and nonfinishers. RESULTS Significant differences were detected among plasma sodium, potassium, and urea nitrogen concentrations measured priorto the start of the ride (ie, TO, TI, and T2). For all variables except chloride and bicarbonate concentrations, significant differences were detected between values obtained prior to the start of the ride and values obtained during the ride (ie, T3 and T4). Only bicarbonate concentration at the 15-km mark of the ride was significant: ly associated with finishing status. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that significant changes in plasma sodium, potassium, and urea nitrogen concentrations can occui-in endurance horses during transport to a competition and when horses are statled overnight before an event. Additionally, a lower bicarbonate concentration following a steep climb early during the ride was associated with subsequent elimination. [ABSTRACT FROM AUTHOR]

Summary: An adult Quarter Horse gelding (Case 1) was evaluated for tachypnoea and acute dysphagia. A 20‐year‐old Quarter Horse gelding (Case 2) was evaluated for respiratory stertor and severe, acute swelling of the head in the submandibular region. A physical examination, complete blood count, blood chemistry, upper airway endoscopy, and peripheral blood Anaplasma phagocytophilum polymerase chain reaction were completed for both horses. Both horses tested positive for A. phagocytophilum. The upper airway endoscopy for Case 1 revealed a feed contaminated pharynx, absent swallowing reflex, and left laryngeal hemiplagia. The upper airway endoscopy for Case 2 revealed severe diffuse pharyngeal swelling occluding the airway. Due to increased respiratory effort in Case 2, a tracheotomy was performed. In both horses, treatment consisted of intravenous oxytetracycline 6.6 mg/kg bwt i.v. q. 24 h for 2–3 days followed by minocycline 4 mg/kg bwt per os q. 12 h for 10–14 days. Both horses made full recoveries. [ABSTRACT FROM AUTHOR]

Background: Trauma from dog attacks has been associated with mortality rates as high as 23% in some species. However, the prognosis and clinical features of this type of injury have not been described in equids. Hypotheses/Objectives: To describe survival rate, signalment, clinical features, and biochemical results in equids presented for emergency care after presumed dog attacks. We hypothesized there would be differences between survivors and nonsurvivors. Animals A total of 28 equids presented for presumed dog attacks from 3 referral centers. Methods: A retrospective study was performed using data from 3 hospitals between 2008 and 2016. Survival was defined as survival at 14 days postdischarge. Variables were compared between survivors and nonsurvivors using a t test, Mann‐Whitney U test, or Fisher's exact test as appropriate. Results: Overall mortality rate was 21%. Ponies and miniature horses represented 16/28 (57%) of the animals in the study. Full‐sized equids had a lower risk of nonsurvival as compared to smaller patients (odds ratio = 0.02; 95% confidence intervals = 0.00‐0.27; P <.005). Animals with lower body temperatures had increased risk for nonsurvival (P =.0004). Increased admission blood lactate concentrations (P =.003) and decreased serum total protein concentrations (P =.006) were associated with nonsurvival. Conclusions: The mortality rate in equids attacked by dogs was similar to what is reported for other veterinary species. Smaller equids and those with increased admission blood lactate concentration, lower body temperature, and lower total serum protein concentrations were less likely to survive. [ABSTRACT FROM AUTHOR]

OBJECTIVE To compare results of point-of-care laboratory testing with standard veterinary clinical examination findings at a single time point during endurance competition to identify horses at risk for elimination. ANIMALS 101 endurance horses participating in the 2013 Western States 160-km (100-mile) endurance ride. PROCEDURES At the 58-km checkpoint, blood samples were collected from all horses. Samples were analyzed for pH, Pco2, base excess, anion gap, PCV, and whole blood concentrations of sodium, potassium, chloride, total carbon dioxide, BUN, glucose, and bicarbonate. Corrected electrolyte and PCV values were calculated on the basis of plasma total protein concentration. Immediately following the blood sample collection, each horse underwent a clinical examination. In addition to standard examination variables, an adjusted heart rate was calculated on the basis of the variable interval between entry into the checkpoint and heart rate recording. A combination of stepwise logistic regression, classification and regression tree analysis, and generalized additive models was used to identify variables that were associated with overall elimination or each of 3 other elimination categories (metabolic elimination, lameness elimination, and elimination for other reasons). RESULTS Corrected whole blood potassium concentration and adjusted heart rate were predictive for overall elimination. Breed, plasma total protein concentration, and attitude were predictive for elimination due to metabolic causes. Whole blood chloride concentration and corrected PCV were predictive for elimination due to lameness. Corrected PCV was predictive for elimination due to other causes. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that for horses in endurance competition, a combination of breed and clinical examination and laboratory variables provided the best prediction of overall elimination. [ABSTRACT FROM AUTHOR]

Objective To describe the clinical and laboratory changes associated with the use of IV0.9% sodium chloride and a commercially available acetated fluid ( CAF) to treat endurance horses requiring emergency medical treatment. Design Randomized, controlled clinical trial from 2007 to 2010. Setting Emergency treatment centers of the Western States 100-mile (220 km) endurance ride. Animals Twelve horses requiring emergency medical treatment in the form of IVfluids completed the study. Interventions Horses were assigned to either the 0.9% sodium chloride group (6 horses) or CAF group (6 horses) and received a total of 20 L of fluid. Clinical, hematologic, and electrolyte data were collected prior to and during fluid therapy. Measurements and Main Results As compared to results prior to fluid therapy, horses treated with 0.9% sodium chloride had a decrease in heart rate ( P < 0.01), PCV ( P < 0.001), total plasma protein (TPP) ( P < 0.001), and the sodium-chloride difference ( P < 0.05). These horses also had an increase in plasma chloride ( P < 0.01) and sodium ( P < 0.01) concentrations. Horses treated with CAF showed a decrease in PCV ( P < 0.01) and TPP ( P < 0.001). Conclusions These findings should aid in the design a larger clinical trial to provide further clarification on the effects of type of fluid therapy on clinical and biochemical parameters in endurance horses. The use of 0.9% sodium chloride may not be ideal for the emergency management of endurance horses as it was associated with an increase in plasma chloride concentration. [ABSTRACT FROM AUTHOR]

Introduction Changes in arterial pressure due to respiratory phases have been used to predict fluid responsiveness in a number of species and pulse pressure variation ( PPV) and systolic pressure variation ( SPV) are commonly used. The relationship between PPV and SPV has not been described in horses. Objectives To describe and compare PPV and SPV values of horses under general anesthesia. Methods Twenty-six horses undergoing general anesthesia and receiving mechanical ventilation were enrolled in the study. Recordings of maximal and minimal values of pulse pressure and systolic pressure were calculated every 15 minutes throughout surgery. Results Initial PPV was 15.6% (7.9, 33.8) and decreased over the first 30 minutes to 10.7 ± 7.2% ( P = 0.03). Initial SPV was 10.3 ± 2.6% and decreased over the first 30 minutes to 7.3 ± 3.3% ( P = 0.004). PPV and SPV had a correlation coefficient of 0.52 ( P < 0.0001) and a 95% limits of agreement from −7.1% to 14.4%. Conclusion PPV and SPV measurements in horses do not have strong agreement. [ABSTRACT FROM AUTHOR]

Objective--To determine values for total body water (TBW), extracellular fluid volume (ECFV), intracellular fluid volume (ICFV), and plasma volume (PV) in healthy neonatal (< 24 hours old) foals and to create a multifrequency bioelectrical impedance analysis (MF-BIA) model for use in neonatal foals. Animals--7 healthy neonatal foals. Procedures--Deuterium oxide (0.4 g/kg, IV), sodium bromide (30 mg/kg, IV), and Evans blue dye (1 mg/kg, IV) were administered to each foal. Plasma samples were obtained following an equilibration period, and the TBW, ECFV, ICFV, and PV were calculated for each foal. An MF-BIA model was created by use of morphometric measurements from each foal. Results--Mean ± SD values were obtained for TBW (0.744 ± 0.024 L/kg), ICFV (0.381 ± 0.018 L/kg), ECFV (0.363 ± 0.014 L/kg), and PV (0.096 ± 0.015 L/kg). The 95% limits of agreement between the MF-BIA and indicator dilution techniques were within ± 2 L for TBW and ECFV. Conclusions and Clinical Relevance--Fluid volumes in neonatal foals were found to be substantially larger than fluid volumes in adult horses. Multifrequency bioelectrical impedance analysis may be a useful technique for predicting TBW, ICFV, and ECFV in neonatal foals. [ABSTRACT FROM AUTHOR]

Objective-To identify risk factors such as signalment, previous competition miles completed, ride characteristics, and physical examination variables associated with the elimination of horses during endurance competitions. Design-Retrospective observational study. Sample-Veterinary records for 3,493 endurance horse competition starts. Procedures-Records were requested of all sanctioned 2007 endurance horse competitions in the United States. Only rides that provided data from all horses were included. The horse's signalment, previous endurance competition record, specific ride characteristics, weight division (ie, based on rider's weight with tack), and physical examination variables throughout the ride were included for analysis. Examination variables were separated into abnormalities occurring prior to the start of the ride, during the first half of the ride, and during the second half of the ride. Multivariate logistic regression was used to identify risk factors for overall elimination and elimination subcategories (lameness and metabolic). Results-Specific breeds, the heavyweight division, and distance of the ride were all associated with an increased risk of elimination. A variety of examination variables prior to the start of the ride and during the ride were associated with elimination and included heart rate, cardiac recovery index, and abnormal gastrointestinal sounds. Conclusions and Clinical Relevance-Results suggested that specific risk factors were associated with elimination of horses from endurance competitions. These factors may be used to help identify horses at higher risk for elimination and prevent morbidity associated with competition. [ABSTRACT FROM AUTHOR]

Objective-To characterize signalment, clinical and laboratory findings, treatment, and outcome in horses with rattlesnake envenomation in northern California. Design-Retrospective case series. Animals-58 client-owned horses evaluated for rattlesnake envenomation at 2 referral hospitals from 1992 to 2009. Procedures-Records of horses with rattlesnake envenomation were reviewed, and data concerning signalment, clinical and laboratory findings, treatment, and outcome were collected. In addition, a rattlesnake-bite severity score (RBSS) was assigned to each horse. Variables were compared between horses that survived and those that did not. Results-The overall mortality rate was 9%. Nine horses received antivenin; no complications were reported and none of the 9 died. The most common laboratory findings associated with severity of envenomation were thrombocytopenia, hypoproteinemia, hyperlactatemia, and a high RBSS. Conclusions and Clinical Relevance-Most horses in this study had a good prognosis after being bitten by rattlesnakes. Laboratory and clinical examination findings may be useful for identifying horses with a poorer prognosis. Treatment with antivenin may be beneficial and warrants further evaluation. [ABSTRACT FROM AUTHOR]

Objective– To describe the clinical and clinicopathologic abnormalities in endurance horses eliminated from competition and requiring emergency medical treatment. Design– Retrospective study over a 2-year period (2005–2006). Ten horses that successfully completed the ride in 2006 were included for comparison. Setting– Temporary equine emergency field hospital. Animals– All horses ( n=30) that were removed from endurance competition and treated for a metabolic abnormality were studied. Interventions– Horses were treated with IV fluids and analgesics. Monitoring included lab work (PCV, total protein, and electrolytes) and serial physical examinations. Statistical analysis included descriptive statistics and parametric and nonparametric comparisons (ANOVA, Friedman's test, and Kruskal-Wallis) where appropriate. Measurements and Main Results– The clinical diagnoses identified included colic, esophageal obstruction, poor cardiovascular recovery, myopathy, and synchronous diaphragmatic flutter. As a group, these sick horses had lower plasma chloride and potassium and higher total plasma protein concentrations as compared with 10 healthy horses that successfully completed the ride ( P<0.05, <0.01, and <0.05 for chloride, potassium, and total protein, respectively). Horses with colic had a lower PCV as compared with horses with poor recovery and those with synchronous diaphragmatic flutter ( P<0.05). All horses, including colics, were treated medically and discharged to owners. Conclusions– Based on the results of this study, the prognosis for horses requiring emergency veterinary treatment after being removed from endurance competition (for metabolic reasons) appears to be good if horses are withdrawn from competition under the same criteria outlined in this study. Biochemical abnormalities tend to be mild and do not necessarily aid in delineating sick horses from successfully completing horses. None of the horses with gastrointestinal disease required abdominal surgery. [ABSTRACT FROM AUTHOR]

Objective--To apply the principle of sodium dilution to calculate the changes in the extracellular fluid (ECF) volume (ECFV) and intracellular fluid volume (ICFV) that occur during dehydration and rehydration in horses. Animals--8 healthy horses of various breeds. Procedures--Horses were dehydrated over 4 hours by withholding water and administering furosemide. Saline (0.9% NaCl) solution was administered IV during the next 2 hours (20 mL/kg/h; total 40 mL/kg). Horses were monitored for an additional hour following IV fluid administration. Initial ECFV was determined by use of multifrequency bioelectrical impedance analysis, and serum sodium concentration was used to calculate total ECF sodium content. Sodium and fluid volume losses were monitored and calculated throughout the study and used to estimate changes in ECFV and ICFV during fluid balance alterations. Results--Changes during dehydration and rehydration primarily occurred in the ECFV. The sodium dilution principle estimated an overexpansion of the ECFV beyond the volume of fluid administered, indicating a small contraction of the ICFV in response to fluid administration. Serum and urinary electrolyte changes were recorded and were consistent with those of previous reports. Conclusions and Clinical Relevance--The sodium dilution principle provided a simple method that can be used to estimate the changes in ECFV and ICFV that occur during fluid administration. Results suggested an overexpansion of the ECFV in response to IV saline solution administration. The sodium dilution principle requires further validation in healthy and clinically ill horses, which could provide clinical applications similar to those in other species. [ABSTRACT FROM AUTHOR]

AIMS: This paper draws together the personal thoughts and critical reflections of key people involved in the establishment of a 'virtual' practice development unit of clinical nurse specialists in the south of England. BACKGROUND: This practice development unit is 'virtual' in that it is not constrained by physical or specialty boundaries. It became the first group of Trust-wide clinical nurse specialists to be accredited in the UK as a practice development unit in 2004. DESIGN AND METHODS: The local university was asked to facilitate the accreditation process via 11 two-hour audio-recorded learning sessions. Critical reflections from practice development unit members, leaders and university staff were written 12 months after successful accreditation, and the framework of their content analysed. FINDINGS AND DISCUSSION: Practice development was seen as a way for the clinical nurse specialists to realize their potential for improving patient care by transforming care practice in a collaborative, interprofessional and evolutionary manner. The practice development unit provided a means for these nurses to analyse their role and function within the Trust. Roberts' identity development model for nursing serves as a useful theoretical underpinning for the reflections contained in this paper. CONCLUSIONS: These narratives provide another example of nurses making the effort to shape and contribute to patient care through organizational redesign. This group of nurses began to realize that the structure of the practice development unit process provided them with the means to analyse their role and function within the organization and, as they reflected on this structure, their behaviour began to change. RELEVANCE TO CLINICAL PRACTICE: Evidence from these reflections supports the view that practice development unit participants have secured a positive and professional identity and are, therefore, better able to improve the patient experience. [ABSTRACT FROM AUTHOR]

Objective—To evaluate selected hemodynamic, blood gas, and biochemical responses to mild to moderate acute blood loss in standing, awake horses. Design—Prospective study. Animals—7 healthy mares. Procedures—Each horse was restrained in standing stocks, and its head was maintained in a neutral position; sedatives and tranquilizers were not administered. During a 1-hour period, blood was collected into collection bags by use of a suction pump. The rate of blood collection was approximately 16 mL/kg/h (7.3 mL/lb/h). Thirty minutes after blood collection, the blood was readministered at the same rate. Central venous pressure (CVP), central venous blood gas, blood lactate concentration, and heart rate were measured at baseline (after placement of catheters), after removal of blood, and after readministration of blood. Results—In response to blood loss, CVP decreased and blood lactate concentration increased significantly compared with baseline values; heart rate and results of central venous blood gas analysis did not change significantly. After readministration of blood, CVP returned to baseline value and blood lactate concentration approached baseline value. Conclusions and Clinical Relevance—Changes in CVP and blood lactate concentration appear to be early indicators of hypovolemia in horses, which may represent acute blood in trauma patients; these variables should be monitored to assess the potential need for blood transfusions. These variables can be used to monitor responses of horses to blood transfusions when whole blood is administered as the replacement fluid. [ABSTRACT FROM AUTHOR]

Objective--To determine the pharmacokinetics and clinical effects of a subanesthetic, continuous rate infusion of ketamine administered to healthy awake horses. Animals--8 adult horses. Procedures--Ketamine hydrochloride was administered to 2 horses, in a pilot study, at rates ranging from 0.4 to 1.6 mg/kg/h for 6 hours to determine an appropriate dose that did not cause adverse effects. Ketamine was then administered to 6 horses for a total of 12 hours (3 horses at 0.4 mg/kg/h for 6 hours followed by 0.8 mg/kg/h for 6 hours and 3 horses at 0.8 mg/kg/h for 6 hours followed by 0.4 mg/kg/h for 6 hours). Concentration of ketamine in plasma, heart rate, respiratory rate, blood pressure, physical activity, and analgesia were measured prior to, during, and following infusion. Analgesic testing was performed with a modified hoof tester applied at a measured force to the withers and radius. Results--No signs of excitement and no significant changes in the measured physiologic variables during infusion rates of 0.4 and 0.8 mg of ketamine/kg/h were found. At 6 hours following infusions, heart rate and mean arterial pressure were decreased, compared with preinfusion measurements. An analgesic effect could not be demonstrated during or after infusion. Pharmacokinetic variables for 0.4 and 0.8 mg/kg/h infusions were not significantly different. Conclusions and Clinical Relevance--Ketamine can be administered to awake horses at 0.4 or 0.8 mg/kg/h without adverse behavioral effects. The observed pharmacokinetic values are different than those reported for single-dose IV bolus administration of this drug. [ABSTRACT FROM AUTHOR]

Aim. The context of this study is a group of clinical nurse specialists from across a Trust seeking accreditation as a practice development unit. The university was asked to facilitate the accreditation process via 11 2-hour learning sessions (including a one-hour focus group). During initial discussions between the university and practice development unit, the overarching research question for this study was set as: 'what are the main roles and responsibilities of clinical nurse specialists?' Background. Although there is no known study of a practice development unit based beyond a ward or speciality, the central tenet of the practice development unit literature is that units must demonstrate their worth if they are to survive and harness senior management support in doing so. Design and methods. Data gleaned from the transcribed audio tape-recordings of the learning sessions were studied at least three times to ensure transcription accuracy and produce detailed charts. Ethical approval was granted by the appropriate Local Research Ethics Committee and written informed consent obtained from clinical nurse specialists. The study lasted 30 months and ended in October 2004. Results. The four crucial statements that give meaning to specialist practice are: quality care giver; expert; information giver and initiator of change. Further analysis reveals the area of corporate and political practice as being missing from this and other lists of clinical nurse specialist attributes found in the literature. Clinical nurse specialists characterize their relationship with the Trust in terms of dichotomy - differing agendas and perceptions of value. Conclusions. The specialist role requires professional development in the areas of corporate and political acumen and professional business management. Relevance to clinical practice. While the findings of this study relate to one Trust and a group of 16 clinical nurse specialists, with careful application they may be transferable to other settings and groups of senior nurses. [ABSTRACT FROM AUTHOR]

Objective: To report the use of a hemoglobin-based oxygen carrier (HBOC) solution in the treatment of parasite-induced anemia in a Barbados sheep and to review the literature related to this disease. Case summary: A 3-month old Barbados sheep was found recumbent, anorexic, and pale. History, laboratory work, and physical examination findings were consistent with inadequate tissue oxygenation because of severe anemia from gastrointestinal parasites. The sheep was treated with 10 mL/kg of an HBOC solution and showed immediate improvement in clinical and laboratory data. The sheep was discharged and had a complete recovery. New information provided: The use of HBOC solutions in sheep has been previously confined to acute hemorrhage in a research setting. This report describes the effects of HBOC administration in an anemic animal displaying signs of inadequate oxygen delivery. [ABSTRACT FROM AUTHOR]

To describe and compare admission colloid osmotic pressure (COP) measurement using both direct and indirect methods in neonatal foals under intensive care, and to evaluate for associations between COP and clinical/clinicopathologic parameters. Prospective study. Intensive care unit at a veterinary medical teaching hospital. Twenty-six critically ill neonatal foals were studied. A control group consisted of 9 clinically healthy neonatal foals. Clinicopathologic data were collected at the time of admission. COP was measured directly using a colloid osmometer. Indirect COP was calculated using equations by both Landis–Pappenheimer (L–P) and Thomas and Brown. Measured admission COP values were 17.1±4.3 and 17.7±2.4 mmHg in critically ill and control foals, respectively, and these values were not significantly different. Critically ill foals with blood lactate concentrations >3 mmol/L had lower COP values than those with lactate ≤3 mmol/L. There was close agreement between indirect COP values calculated using the L–P equation and direct COP values measured in control foals (mean error=0.0±1.3 mmHg; R2=0.87). However, indirect values were not as predictive of direct COP in critically ill foals (mean error=0.8±3.8 mmHg; R2=0.64). As COP values increased, the indirect method tended to overestimate COP, whereas at lower values it slightly underestimated COP. While the L–P equation was a close approximation of direct COP in healthy foals, direct measurements of oncotic pressure cannot be replaced for monitoring of critically ill foals. Critically ill foals with higher lactate concentrations had lower COP values, suggesting a possible relationship between COP and lactate. [ABSTRACT FROM AUTHOR]

Objective--To evaluate the use of multifrequency bioelectrical impedance analysis (MF-BIA) for estimating total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV) in horses. Animals--9 healthy mares. Procedure TBW and ECFV were measured by use of deuterium oxide and sodium bromide dilution techniques, respectively. Intracellular fluid volume was calculated as the difference between TBW and ECFV. Concurrently, MF-BIA recordings were obtained by use of 4 anatomic electrode positions and 3 measurements of length. Models for MF-BIA data were created for all combinations of length and anatomic electrode position. Models were evaluated to determine the position-length configuration that provided the most consistent estimates of TBW, ECFV, and ICFV, compared with values determined by use of the dilution techniques. Results--Positioning electrodes over the ipsilateral carpus and tarsus and use of height at the tuber sacrale for length provided the closest estimate between values for TBW, ECFV, and ICFV predicted by use of MF-BIA and measured values obtained by dilutional techniques. This model had the narrowest 95% limits of agreement. Conclusions and Clinical Relevance--MF-BIA techniques have been used to predict changes in TBW, ECFV, and ICFV in healthy and diseased humans. Results reported in this study provide an equine-specific model to serve as the basis for further evaluation of MF-BIA in horses with altered fluid states. The MF-BIA techniques have a number of potential applications for use in horses, including evaluation of exercise physiology, pharmacologic studies, and critical-care management. [ABSTRACT FROM AUTHOR]

Upper Devonian to Lower Carboniferous strata of the Campwyn Volcanics of east central Queensland preserve a substantial sequence of first-cycle volcaniclastic sedimentary and coeval volcanic rocks that record prolonged volcanic activity along the northern New England Fold Belt. The style and scale of volcanism varied with time, producing an Upper Devonian sequence of mafic volcano-sedimentary rocks overlain by a rhyolitic ignimbrite-dominated sequence that passes upward into a Lower Carboniferous limestone-bearing sedimentary sequence. We define two facies associations for the Campwyn Volcanics. A lower facies association is dominated by mafic volcanic-derived sedimentary breccias with subordinate primary mafic volcanic rocks comprising predominantly hyaloclastite and peperite. Sedimentary breccias record episodic and high energy, subaqueous depositional events with clastic material sourced from a mafic lava-dominated terrain. Some breccias contain a high proportion of attenuated dense, glassy mafic juvenile clasts, suggesting a syn-eruptive origin. The lower facies association coarsens upwards from a lithic sand-dominated sequence through a thick interval of pebble- to boulder-grade polymict volcaniclastic breccias, culminating in facies that demonstrate subaerial exposure. The silicic upper facies association marks a significant change in eruptive style, magma composition and the nature of eruptive sources, as well as the widespread development of subaerial depositional conditions. Crystal-rich, high-grade, low- to high-silica rhyolite ignimbrites dominate the base of this facies association. Biostratigraphic age controls indicate that the ignimbrite-bearing sequences are Famennian to lower-mid Tournaisian in age. The ignimbrites represent extra-caldera facies with individual units up to 40 m thick and mostly lacking coarse lithic breccias. Thick deposits of pyroclastic material interbedded with fine-grained siliceous sandstone and mudstone (locally... [ABSTRACT FROM AUTHOR]

The Westphalian (Upper Carboniferous) Coal Measures of the Durham coalfield in NE England were deposited in lower and upper delta plain environments. Distributory channels crossed the plain and were separated by shallow, interdistributary lakes and bays. Detailed observation of three-dimensional (3-D) opencast (surface) mine expousures, in collaboration with subsurface borehole analysis, has revealed the existence of five varieties of channel deposits and two associated overbank facies within the Durham Coal Measures. Major distributory channels were the major avenues of sediment transport across the Coal Measures plain, were variably sinous, mostly 1-2km wide and deposited belts of sand mostly up to 5 km wide. Proximal, major crevasse splay channels formed by the breaching of major channel banks during flood events, were straight, sand-filled and up to 400 m wide. Minor distributory channels formed by the sustained operation of such crevasses, varied from straight to highly sinous, and deposited 'shoestring' sand/mud belts up to a few hundred metres wide. Minor crevasse channels, generally straight and up to 50 m wide, were formed down-palaeocurrent extensions of minor distributaries which supplied interdistributary minor delta subsystems, were generally straight and up to 200 m wide. Of the two types of channel overbank (leave) deposits recognized, one comprising thinly interbedded fine-grained sandstone/claystone, is mostly, though not exclusively, associated with major distributary channels. The other, consisting of 'massive' siltstones with regularly spaced, thin claystone bands, is uniquely developed at the margins of minor distributary channels. The lower part of the Westphalian A succession in the northern Pennines records a change in the depositional environment upwards from a lower to upper delta plain. Through this transition, major channel deposits show evidence of having evolved from being of dominantly low sinuosity to being more variable in... [ABSTRACT FROM AUTHOR]

A 3.5-year-old miniature horse gelding was evaluated for signs of colic and decreased faecal production. Initial clinical pathology showed severe hypoproteinaemia with an albumin concentration <10 g/l. Abdominal ultrasound identified multiple loops of small intestine with significantly increased wall thickness. Diagnosis of equine proliferative enteropathy was based on clinical and laboratory findings, as well as a positive faecal polymerase chain reaction and positive antibody titre (>1:240) to Lawsonia intracellularis. Treatment with intravenous oxytetracylcine and additional supportive care gradually resolved the clinical and laboratory abnormalities. [ABSTRACT FROM AUTHOR]

The characteristics, history, clinical signs, treatment and outcome of nine horses with abscesses caused by Actinomyces species were reviewed. DNA sequencing was used to determine the species of one of the isolates. The horses were one to 11 years of age, and the abscesses were most commonly located in the submandibular and retropharyngeal regions. The bacterium was usually cultured as the sole isolate and the horses were most often affected in the autumn. Most of the abscesses were treated with antimicrobials and drainage, but some of them recurred. The horses with submandibular abscesses had residual scar tissue that in some cases did not resolve. [ABSTRACT FROM AUTHOR]

Fecal shedding of Salmonella spp. was recently documented in 8% of endurance horses presented to equine referral centers for colic. Previous studies have documented fecal shedding of Salmonella spp. in as few as 0.8% of the general horse population, although horses with colic appear to be at higher risk. Fecal Salmonella spp. shedding before and after endurance horse competitions has not been evaluated. Fecal samples were collected from 204 horses during three separate 100 mile endurance competitions. Following incubation in selenite broth, 289 fecal samples were tested by real-time PCR analysis for Salmonella spp. Only one post-race sample (0.5% tested positive for Salmonella spp. in this study and no pre-race sample was available from this horse. Results suggest that fecal shedding of Salmonella spp. is uncommon in endurance horses during competitions. Further research is needed to confirm and identify the source of Salmonella spp. infection in endurance horses with colic requiring treatment at referral centers. [ABSTRACT FROM AUTHOR]

The Drummond Basin of central Queensland preserves a large-volume succession of little studied, predominantly fluviatile, coarse-grained sedimentary rocks of mid-Mississippian age. The stratigraphy of the basin has been subdivided into three sedimentary cycles. The Cycle 1/Cycle 2 boundary records a distinct, but poorly understood change in provenance from a volcanic-dominated succession related to initial basin rifting (Cycle 1) to a quartz-rich, craton-derived succession (Cycle 2). Cycle 3 has been thought to mark a resumption of intrabasinal volcanism and related sedimentation. The purpose of this study was to enhance the understanding of the basin-wide siliciclastic sedimentation of Cycles 2 and 3, and causes for the changes in sediment provenance. This objective was achieved by constraining large-scale spatial and temporal depositional trends and investigating sediment transport pathways into and through the basin. Petrographic, QFL, paleocurrent and conglomerate clast analyses were undertaken. The observations presented here have several implications relevant to understanding the stratigraphy of the Drummond Basin and regional tectonic events at this time. Cycle 3 is revised here primarily to be a continuation of Cycle 2-style basement-derived sedimentation, rather than recording a resumption of volcanism in the area, as per prevailing models. Quartz-rich sedimentation in the Drummond Basin was, therefore, more long-lived than previously envisaged, and once established, was not significantly disrupted by volcanism. Cycle 2 formation thicknesses appear highly variable across the basin. This is unlikely to be a result of pre-existing rift-related topography as suggested in previous models. The thickness variations are more likely related to sediment bypassing and post-depositional deformation in the area. The distinctive coarse-grained, relatively quartz-rich sedimentation of Cycles 2 and 3 is unusual in its volume and extent. The sediment was transported into the basin from its southern/southwestern margin, implying long-distance transport and extrabasinal sediment supply. While the specific source terrain(s) remain unknown, one plausible tectonic driver was far-field influence of the intraplate Alice Springs Orogeny. [ABSTRACT FROM AUTHOR]

The lowest 501 m (~1139-638 m) of the AND-2A core from southern McMurdo Sound is the most detailed and complete record of early Miocene sediments in Antarctica and indicates substantial variability in Antarctic ice sheet activity during early Miocene time. There are two main pulses of diamictite accumulation recorded in the core, and three significant intervals with almost no coarse clasts. Each diamictite package comprises several sequences consistent with ice advance-retreat episodes. The oldest phase of diamictite deposition, Composite Sequence 1 (CS1), has evidence for grounded ice at the drill site and has been dated around 20.2-20.1 Ma. It likely coincides with cooling associated with isotope event Mi1aa. This is overlain by a diamictite-free, sandstone-dominated interval, CS2 that includes three coarsening-upward deltaic cycles, is inferred to mark substantial warming, and has an inferred age range between 20.1 and 20.05 Ma. Above this is an interval with variable amounts of diamictite (CS3), with indicators of ice grounding, that is inferred to record ice advance relative to CS2, and is overlain by an ~100-m-thick mud-rich interval (CS4) with no sedimentological evidence for direct glacial influence at the drill site (ca. 19.4-18.7 Ma). A third overlying diamictite-rich interval (CS5) overlies an unconformity spanning 18.7-17.8 Ma (coinciding with isotope event Mi1b), and records a return to more ice-influenced conditions at the drill site in late early Miocene time. The overall picture for the early Miocene (spanning the period 20.2-17.35 Ma) is one of ice advance alternating with periods of ice retreat and hence significant global climate fluctuations after the permanent establishment of the Antarctic ice sheet at the Eocene/Oligocene boundary, and preceding the relative warmth of the middle Miocene climatic optimum (ca. 17.5-14.5 Ma). Sedimentary cyclicity in CS1 and CS2 is consistent with ~21 k.y. precession but in CS3 the frequency is closer to 100 k.y. (consistent with eccentricity), with a possible change to 20 k.y. precession in CS4. CS5 cyclicity is consistent with obliquity forcing. Provenance data are consistent with local Transantarctic Mountains glacial activity under precessional control in CS1 and more southerly ice-cap build up under 100 k.y. eccentricity and obliquity control during CS3 and CS5, respectively. [ABSTRACT FROM AUTHOR]

The primary classes of drugs used for pain control in horses include the non-steroidal anti-inflammatory drugs (NSAIDS), the alpha-2 agonists, and the opiates, but each of these drug classes has significant adverse effects. Ketamine hydrochloride is a non-competitive antagonist at N-methyl D-aspartate (NMDA) receptors in the spinal cord and has been used in both dogs and humans to provide analgesia. The purpose of this study was to identify a safe administration rate for a continuous infusion of ketamine to awake horses and describe the clinical effects of this infusion. Six horses were administered a continuous infusion of ketamine hydrochloride at a low dose (0.4 mg/kg/hr) and high dose (0.8 mg/kg/hr). Each infusion took place over 6 hours and the horses were monitored during infusion as well as for the 6 hours post-infusion. The following parameters were evaluated: heart rate, blood pressure, respiratory rate, activity level, and analgesic thresholds. Both the low dose and high dose rates were tolerated well by all horses with no signs of excitation or discomfort. Post-infusion heart rate and mean arterial blood pressure were significantly decreased as compared to pre-infusion values (p=0.02 and p=0.02, respectively) A significant increase in analgesic threshold was not identified. Subanesthetic infusions of ketamine to awake horses appear to be well tolerated and cause only mild changes in clinical parameters. Further research is needed to evaluate the analgesic potential of these infusions. [ABSTRACT FROM AUTHOR]

Abstract. Strophingia ericae (Curtis) (Homoptera: Psylloidea) takes one or two years to complete its life cycle. In both cases eggs hatch over a prolonged period from midsummer, possibly extending into the following spring at high altitude, and instars overlap in time. Instar III is the predominant overwintering stage in the lowland, annual cycle, whereas in the upland, biennial cycle most first-year nymphs overwinter in instars I and II and most second-year nymphs in instar V. When moved to the laboratory, instars IV and V from a predominantly annual population showed accelerated development in response to elevated temperatures and to long days in both mid-winter and early spring. In the biennial life cycle, short autumn days retard instar V development but the response to photoperiod disappears by the end of winter. Exposure to LD 18 : 6 h retarded development of early instars in the annual population, resulting in an accumulation in instar III. The proportion of overwintering instars I and II rises with increase in altitude and moult to instar III becomes progressively delayed. Nymphs that reach instar III under long daylengths in the year following hatching are channelled towards the biennial cycle. Exposure of a predominantly biennial population to 15 °C and LD 18 : 6 h after midsummer, thus avoiding autumn conditions, promoted the rapid development of overwintered nymphs, switching the cycle from biennial to annual. [ABSTRACT FROM AUTHOR]

The Upper Devonian to Lower Carboniferous volcanosedimentary rocks of the Yarrol terrane of the northern New England Fold Belt have previously been ascribed to a forearc basin setting. New data presented here, however, suggest that the Yarrol terrane developed as a backarc basin during the Middle to early Late Devonian. Based on field studies, we recognise four regionally applicable stratigraphic units: (i) a basal, ?Middle to Upper Devonian submarine mafic volcanic suite (Monal volcanic facies association); (ii) the lower Frasnian Lochenbar beds that locally unconformably overlie the Monal volcanic facies association; (iii) the Three Moon Conglomerate (Upper Devonian - Lower Carboniferous); and (iv) the Lower Carboniferous Rockhampton Group characterised by the presence of oolitic limestone. Stratigraphic and compositional differences suggest the Monal volcanic facies association post-dates Middle Devonian silicic-dominated magmatism that was coeval with gold-copper mineralisation at Mt Morgan. The Lochenbar beds, Three Moon Conglomerate and Rockhampton Group represent a near-continuous sedimentary record of volcanism that changed in composition and style from mafic effusive (Late Devonian) to silicic explosive volcanism (Early Carboniferous). Palaeocurrent data from the Three Moon Conglomerate and Rockhampton Group indicate dispersal of sediment to the west and northwest, and are inconsistent with derivation from a volcanic-arc source situated to the west (Connors-Auburn Arch). Geochemical data show that the Monal volcanic facies association ranges from tholeiitic subalkaline basalts to calc-alkaline basaltic andesite. Trace and rare-earth element abundances are distinctly MORB-like (e.g. light rare earth element depletion), with only moderate enrichment of the large-ion lithophile elements in some units, and negative Nb anomalies, suggesting a subduction-related signature. Basalts of the Monal volcanic facies association are best described as transition... [ABSTRACT FROM AUTHOR]

We conducted a survey and semi-structured qualitative interviews to investigate current anaesthetic practice for arteriovenous fistula formation surgery in the UK. Responses were received from 39 out of 59 vascular centres where arteriovenous access surgery is performed, a response rate of 66%. Thirty-five centres reported routine use of brachial plexus blocks, but variation in anaesthetic skill-mix and practice were observed. Interviews were conducted with 19 clinicians from 10 NHS Trusts including anaesthetists, vascular access and renal nurses, surgeons and nephrologists. Thematic analysis identified five key findings: (1) current anaesthetic practice showed that centres could be classified as 'regional anaesthesia dominant' or 'local anaesthesia/mixed'; (2) decision making around mode of anaesthesia highlighted the key role of surgeons as frontline decision makers across both centre types; (3) perceived barriers and facilitators of regional block use included clinicians' beliefs and preferences, resource considerations and patients' treatment preferences; (4) anaesthetists' preference for supraclavicular blocks emerged, alongside acknowledgement of varied practice; (5) there was widespread support for a future randomised controlled trial, although clinician equipoise issues and logistical/resource-related concerns were viewed as potential challenges. The use of regional anaesthesia for arteriovenous fistula formation in the UK is varied and influenced by a multitude of factors. Despite the availability of anaesthetists capable of performing regional blocks, there are other limiting factors that influence the routine use of this technique. The study also highlighted the perceived need for a large multicentre, randomised controlled trial to provide an evidence base to inform current practice. [ABSTRACT FROM AUTHOR]

Summary: Background: Emerging experimental evidence suggests that air pollution may contribute to development of obesity and diabetes, but studies of children are limited. Objectives: We hypothesized that pollution effects would be magnified after bariatric surgery for treatment of obesity, reducing benefits of surgery. Methods: In 75 obese adolescents, excess weight loss (EWL), high‐density lipoprotein (HDL) cholesterol, triglycerides, alkaline phosphatase (ALP) and hemoglobin A1c (HbA1c) were measured prospectively at baseline and following laparoscopic adjustable gastric banding (LAGB). Residential distances to major roads and the average two‐year follow‐up exposure to particulate matter <2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone were estimated. Associations of exposure with change in outcome and with attained outcome two years post‐surgery were examined. Results: Major‐roadway proximity was associated with reduced EWL and less improvement in lipid profile and ALP after surgery. NO2 was associated with less improvement in HbA1c and lower attained HDL levels and change in triglycerides over two years post‐surgery. PM2.5 was associated with reduced EWL and reduced beneficial change or attained levels for all outcomes except HbA1c. Conclusions: Near‐roadway, PM2.5 and NO2 exposures at levels common in developed countries were associated with reduced EWL and metabolic benefits of LAGB. This novel approach provides a model for investigating metabolic effects of other exposures. [ABSTRACT FROM AUTHOR]

The Texas Orocline is a prominent orogenic curvature that developed during the early Permian in the southern New England Orogen. Outliers preserving lower Permian sedimentary successions (Bondonga, Silver Spur, Pikedale, Terrica, Alum Rock and Ashford beds) approximately outline the oroclinal structure, but the tectonic processes responsible for the development of these basinal successions, and their relationships to the Texas Orocline, are unclear. Here we address this shortcoming by providing new U–Pb detrital and primary zircon ages from these successions, as well as detailed stratigraphic and structural data from the largest exposed succession (Bondonga beds). Field observations and U–Pb geochronological data suggest that the lower Permian successions in the Texas Orocline are remnants of a single, formerly larger basin that was deposited afterca302 Ma. Time constraints for formation of this basin are correlative with constraints from the lower Permian Nambucca Block, which was likely deposited in response to regional back-arc extension during and/or after the development of the Texas Orocline. The conclusion that the lower Permian sedimentary basins in the Texas Orocline belong to this back-arc extensional system supports the suggestion that oroclinal bending in the New England Orogen was primarily controlled by trench retreat and associated overriding-plate extension. [ABSTRACT FROM AUTHOR]

In 2007, the Antarctic Geological Drilling Program (ANDRILL) drilled 1138.54 m of strata ~10 km off the East Antarctic coast, includ ing an expanded early to middle Miocene succession not previously recovered from the Antarctic continental shelf. Here, we pre sent a facies model, distribution, and paleoclimatic interpretation for the AND-2A drill hole, which enable us, for the first time, to reconstruct periods of early and middle Miocene glacial advance and retreat and paleo environmental changes at an ice-proximal site. Three types of facies associations can be recognized that imply significantly different paleoclimatic interpretations. (1) A diamictite-dominated facies association represents glacially dominated depositional environments, including subglacial environments, with only brief intervals where ice-free coasts existed, and periods when the ice sheet was periodically larger than the modern ice sheet. (2) A stratified diamictite and mudstone facies association includes facies characteristic of open-marine to iceberg-influenced depositional environments and is more consistent with a very dynamic ice sheet, with a grounding line south of the modern position. (3) A mudstone-dominated facies association generally lacks diamictites and was produced in a glacially influenced hemipelagic depositional environment. Based on the distribution of these facies associations, we can conclude that the Antarctic ice sheets were dynamic, with grounding lines south of the modern location at ca. 20.1--19.6 Ma and ca. 19.3--18.7 Ma and during the Miocene climatic optimum, ca. 17.6--15.4 Ma, with ice-sheet and sea-ice minima at ca. 16.5--16.3 Ma and ca. 15.7--15.6 Ma. While glacial minima at ca. 20.1--19.6 Ma and ca. 19.3--18.7 Ma were characterized by temperate margins, an increased abundance of gravelly facies and diatomaceous siltstone and a lack of meltwater plume deposits suggest a cooler and drier climate with polythermal conditions for the Miocene climatic optimum (ca. 17.6--15.4 Ma). Several periods of major ice growth with a grounding line traversing the drill site are recognized between ca. 20.2 and 17.6 Ma, and after ca. 15.4 Ma, with evidence of cold polar glaciers with ice shelves. The AND-2A core provides proximal evidence that during the middle Miocene climate transition, an ice sheet larger than the modern ice sheet was already present by ca. 14.7 Ma, ~1 m.y. earlier than generally inferred from deep-sea oxygen isotope records. These findings highlight the importance of high-latitude ice-proximal records for the interpretation of far-field proxies across major climate transitions. [ABSTRACT FROM AUTHOR]

The sources and fluxes of sediment to the Great Barrier Reef lagoon from north-eastern Australian rivers have been the subject of much concern and study, with the large catchments of the Burdekin and Fitzroy Rivers thought to be the key sources at present. Here, the utility of newly developed magnetic ‘fingerprinting’ methods for identifying sediment provenance, both onshore and offshore, and in association with individual large flood events, is investigated. Within the Burdekin catchment, sediments are mobilized from different subcatchments by runoff generated by intense, localized rainfall events. Magnetic measurements were made on untreated and acid-treated samples of river channel sediments within the Burdekin River subcatchments and from the estuarine and inner shelf depocentres of Burdekin River sediments. The acid treatment removes all discrete magnetic particles and coatings, and leaves magnetic inclusions (protected within host silicate grains) as the basis of the measured magnetic signature of a sample. The magnetic properties of the acid-treated samples display statistically distinct sediment provenance groupings. Sand samples from the Upper Burdekin River appear magnetically distinct from samples from tributaries of the Burdekin (e.g. Hann Creek, Fanning River) and also from nearby coastal rivers, including the Haughton. Suspended sand samples from a Burdekin flood event in 2000 appear to have a different source compared with those from floods in 1998 and 1999. Comparisons of the terrestrial, acid-treated sand fractions with the same, acid-treated, sand-size fractions from transects taken offshore suggest that the surface sediments in Upstart Bay and Bowling Green Bay have different sources. Some of these sources are as yet unidentified but may represent the unsampled, lower-discharge south-western Burdekin subcatchments, and/or along-shore drift of sand from the south, perhaps even from the Fitzroy River, over millennial timescales of cyclone pumping. The magnetic inclusion method precludes any obfuscation or confounding of sediment source, which might arise from hydraulic sorting and/or post-depositional magnetic diagenesis or authigenesis. [ABSTRACT FROM AUTHOR]

The liver X receptor (LXR) agonist TO901317 inhibited the synthesis of apolipoprotein A1 (apo A1) by human liver-derived cells, including the formation of lipid-poor, prebeta-migrating high-density lipoprotein (HDL). Despite activation of the lipid transporter ABCA1 under these conditions, cellular efflux of PL and cholesterol from liver cells was also reduced. By assaying transcription from full-length and truncated promoters and by site-directed mutagenesis, the effect of LXR and its ligand was localized to a binding site for hepatic nuclear factor-4 (HNF4) in the proximal apo A1 promoter (−132/−119 bp). Chromatin immunoprecipitation analysis of apo A1 transcription complexes from control and ligand-activated cells showed an increase in the binding of reported apo A1 transcriptional inhibitor COUP-TF, which competes with HNF4 for DNA binding. It also identified LXR in the apo A1 transcription complex of TO901317-treated cells. Displacement of HNF4 from the −132/−119 bp promoter DNA sequence in the presence of TO901317 was confirmed by gel shift analysis. These data indicate that LXR can be a significant negative regulator of apo A1 transcription and HDL synthesis. [ABSTRACT FROM AUTHOR]

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of zircons confirm o Late Devonian to Early Carboniferous age (ca 360-350 Ma) for silicic volcanic rocks of the Compwyn Volcanics and Yarrol terrane of the northern New England Fold Belt (Queensland). These rocks ore coeval with silicic volcanism recorded elsewhere in the fold belt of this time (Connors Arch, Drummond Basin). The new U-Pb zircon ages, in combination with those from previous studies, show that silicic magmatism was both widespread across the northern New England Fold Belt (>250 000 km² and &les;500 km inboard of plate margin) and protracted, occurring over o period of -15 million years. Zircon inheritance is commonplace in the Late Devonian - Early Carboniferous volcanics, reflecting anatectic melting and considerable reworking of continental crust, Inherited zircon components range from ca 370 to co 2050 Ma, with Middle Devonian (385-370 Ma) zircons being common to almost ail dated units. Precambrian zircon components record either Precambrian crystalline crust or sedimentary accumulations that were present above or within the zone of magma formation. This contrasts with a lock of significant zircon inheritance in younger Permo-Carboniferous igneous rocks intruded through, and emplaced on top of, the Devonian-Carboniferous successions. The inheritance data and location of these volcanic rocks of the eastern margins of the northern New England fold Belt, coupled with Sr-Nd, Pb isotopic data and depleted mantle model ages for Late Palaeozoic and Mesozoic magmatism, imply that Precambrian mafic and felsic crustal materials (potentially as old as 2050 Ma), or of fhe very least Lower Palaeozoie rocks derived from the reworking of Precambrian racks, comprise basemen to the eastern parts of the foid belf. This crustal basement architecture may be a relief from the Late Proterozoic breakup of the Rodinian supercontinent. [ABSTRACT FROM AUTHOR]