Left ventricular size and systolic function in Thoroughbred racehorses and their relationships to race performance

Cardiac morphology in human athletes is known to differ, depending on the sports-specific endurance component of their events, whereas anecdotes abound about superlative athletes with large hearts. As the heart determines stroke volume and maximum O2 uptake in mammals, we undertook a study to test the hypothesis that the morphology of the equine heart would differ between trained horses, depending on race type, and that left ventricular size would be greatest in elite performers. Echocardiography was performed in 482 race-fit Thoroughbreds engaged in either flat (1,000–2,500 m) or jump racing (3,200–6,400 m). Body weight and sex-adjusted measures of left ventricular size were largest in horses engaged in jump racing over fixed fences, compared with horses running shorter distances on the flat (range 8–16%). The observed differences in cardiac morphologies suggest that subtle differences in training and competition result in cardiac adaptations that are appropriate to the endurance component of the horses' event. Derived left ventricular mass was strongly associated with published rating (quality) in horses racing over longer distances in jump races ( P ≤ 0.001), but less so for horses in flat races. Rather, left ventricular ejection fraction and left ventricular mass combined were positively associated with race rating in older flat racehorses running over sprint (<1,408 m) and longer distances (>1,408 m), explaining 25–35% of overall variation in performance, as well as being closely associated with performance in longer races over jumps (23%). These data provide the first direct evidence that cardiac size influences athletic performance in a group of mammalian running athletes.

The effects of halothane and isoflurane on cardiovascular function in laterally recumbent horses

BACKGROUND

Experimental studies in adult horses have shown that general anaesthesia maintained with isoflurane is associated with less depression of cardiovascular function compared with halothane anaesthesia. Adverse effects of intermittent positive-pressure ventilation (IPPV) have also been demonstrated. Nevertheless, the haemodynamic effects of these agents and the effects of differing modes of ventilation have not been assessed during clinical anaesthesia in horses undergoing surgery.

METHODS

The haemodynamic effects of isoflurane or halothane anaesthesia during spontaneous or IPPV were studied non-invasively in 32 laterally recumbent horses undergoing elective surgery. Indices of cardiac function and measurements of femoral arterial blood flow and resistance were recorded using transoesophageal and transcutaneous Doppler echocardiography, respectively. Arterial pressure was measured directly using a facial artery catheter.

RESULTS

Cardiac index (CI) was significantly higher during isoflurane anaesthesia than during halothane anaesthesia and was also higher during spontaneous ventilation with isoflurane. CI decreased significantly over time and an inverse relationship was observed between CI and mean arterial pressure (MAP). Horses with higher MAP had a significantly lower CI. During isoflurane anaesthesia, femoral arterial blood flow was significantly higher in both pelvic limbs compared with halothane anaesthesia, and flow in the lower limb was significantly higher during spontaneous ventilation than during IPPV. No significant change in femoral blood flow was observed over time.

CONCLUSION

The effects of anaesthetics and mode of ventilation on cardiovascular function recorded under surgical conditions in horses are similar to those reported under experimental conditions. However, in contrast with previous experimental studies, CI progressively decreased over time regardless of agent used or mode of ventilation employed.

Disseminated Beauveria bassiana infection in a patient with acute lymphoblastic leukemia

We describe a case of disseminated Beauveria bassiana infection in a patient with acute lymphoblastic leukemia. Her infection was successfully treated with amphotericin B and itraconazole. B. bassiana is rarely reported as a human pathogen. It is commonly found in soil and because of its pathogenicity to many insect species is incorporated into several pesticides.

Comparison of intradermal and serum testing for allergen-specific IgE using a Fcepsilon RIalpha-based assay in atopic dogs in the UK

Atopic dermatitis in dogs is a common allergic skin disease that affects substantial numbers of dogs in the UK. The purpose of this study was to compare the results of an intradermal test (IDT) and an in vitro test in a large cohort of dogs. Dogs were intradermal tested with Greer allergens (Greer Labs Inc, Lenoir, NC, USA) using standard techniques. At the same time blood samples were drawn and submitted for evaluation by ELISA using the ALLERCEPT Definitive Allergen Panels for allergen-specific IgE, a commercial assay that uses a biotinylated recombinant extracellular domain of the high affinity Fc-epsilon receptor alpha chain protein (Fcepsilon RIalpha). The allergens used in the two tests included grass, tree and weed pollens, moulds, flea saliva/whole flea extract and house dust mite species. The optical density readings from the ELISA for each allergen were compared with the results of the IDT for 265 dogs. The prevalence of positive reactions in the ELISA was equal to or greater than the results of the IDT in the case of almost all of the allergens, but two notable exceptions were the house dust mites Dermatophagoides farinae and Dermatophagoides pteronyssinus. These two allergens were the most common positive reactions by IDT (prevalence D. farinae 78.9%, D. pteronyssinus 66.4%). The results of the two tests were significantly different (McNemar's test, P<0.05) for 16 of the 22 allergens. The sensitivities of the ELISA compared to the IDT (where there were more than 3 dogs with positive reactions in both tests) varied between 19.3 and 77.1% (D. pteronyssinus 19.3% and D. farinae 67.9%) and the specificities varied between 64.2 and 96.6% (D. pteronyssinus 96.6% and D. farinae 89.3%).

Isolation of two phenylethanoid glycosides from Eremophila gilesii

The leaves of Eremophila gilesii have been used traditionally to treat colds, headaches, sores, and chest pains. Our previous screening of Australian native plants showed that the methanol extract of the aerial parts of E. gilesii demonstrated notable inhibition of ADP-induced human platelet aggregation and serotonin release. Subsequent fractionation on the methanol extract led to the isolation of two phenylethanoid glycosides, verbascoside (1) and poliumoside (2). This is the first study reporting the presence of phenylethanoid glycosides in E. gilesii.

Sequence and genetic arrangement of the UL region of the monkey B virus (Cercopithecine herpesvirus 1) genome and comparison with the UL region of other primate herpesviruses

The complete DNA sequence of the unique long (U(L)) region of monkey B virus (BV) was determined. Based on sequence homology and the presence of transcriptional control element motifs, homologues of every open reading frame present in the U(L) region of the Human herpesvirus 1 (herpes simplex virus 1, HSV-1) and Human herpesvirus 2 (herpes simplex virus 2, HSV-2) genomes were identified in BV. The BV genes are arranged in the same order and orientation as in HSV. These results demonstrate that the BV U(L) region is entirely co-linear with that of HSV-1 and HSV-2.

Heritability and epidemiology of canine hip-dysplasia score and its components in Labrador retrievers in the United Kingdom

Hip-dysplasia (malformation of the coxofemoral joint) in dogs is a major health problem. Under the British Veterinary Association/Kennel Club's voluntary hip-dysplasia scheme, dog-owners/breeders submit radiographs from animals >1-year-old, to ensure adequate skeletal maturity. An overall hip score quantifies the degree of malformation in the hip joints of these animals, by summing the scores for nine components of the radiographs of both the left and right joints. The hip score data for 29,610 Labrador retrievers (registered with The Kennel Club, UK) were merged with the Kennel Club pedigree database for 472,435 Labrador retrievers. The merged data included the animal's identity, date of birth, sex and hip score and similar records for the dog's relatives, including the hip score if the relative had been tested. In recent years, breeding had been increasingly from tested parents. The mean hip score for male Labradors was significantly higher than that for females. Regression modelling showed a significant, positive dependence of the hip score of the offspring upon the hip scores of its sire, dam and grandparents. Genetic heritability (using data from 13,382 Labrador retrievers comprising 718 litters) was highly significant: 0.34 from the two parents, 0.41 from sire alone and 0.30 from dam alone. Using components data from 2038 offspring Labrador retrievers comprising 1248 litters, three similar estimates of heritability were significant for three major components (Norberg angle, cranial acetabular edge and subluxation); for other components, heritability was significant from the sire but not from the dam. Offspring hip score could be reduced substantially by using only parents with zero hip score.

Canine neoplasia in the UK: estimates of incidence rates from a population of insured dogs

Neoplasia is common in pet dogs but accurate figures for the incidence of tumours in this, as in other species, are sparse. The purpose of this study was to document the occurrence of tumours in a defined population of dogs. From a database of 130,684 insured dogs, claims relating to the investigation or treatment of tumours or tumour-like lesions during a 12-month period were accessed and followed up. A total of 2,546 claims were tumour related and were classified according to tumour site and type. Because the demographics of the insured population were skewed towards younger animals, a standard population, as described in the veterinary literature, was used in the calculation of tumour incidence rates. The skin and soft tissues were the most common sites for tumour development, with a standardised incidence rate of 1,437 per 100,000 dogs per year, followed by alimentary (210), mammary (205), urogenital (139), lymphoid (134), endocrine (113) and oropharyngeal (112). Canine cutaneous histiocytoma was the most common single tumour type, with a standardised incidence rate of 337 per 100,000 dogs per year, followed by lipoma (318), adenoma (175), soft tissue sarcoma (142), mast cell tumour (129) and lymphosarcoma (114). These data are unique and provide a valuable basis for future research into the aetiology and epidemiology of canine tumours.

The effect of troglitazone biliary excretion on metabolite distribution and cholestasis in transporter-deficient rats

We investigated whether lack of the canalicular multispecific organic anion transporter in transport-deficient (TR-) rats would result in plasma and urinary accumulation of troglitazone or its major metabolites and whether any accumulation would be associated with increased levels of bilirubin or bile acids. Administration of a single oral dose of troglitazone (200 mg/kg) to TR- rats resulted in 2- and 50-fold increases in plasma levels and 30- and 500-fold increases in urinary amounts of troglitazone sulfate and troglitazone glucuronide, respectively, compared with normal rats. No changes were found in the plasma concentrations and urinary amounts of troglitazone or troglitazone-quinone. Accumulation of troglitazone metabolites in plasma was accompanied by a 2-fold increase in the serum level of conjugated bilirubin in TR- rats, whereas no changes were observed in normal animals. Bile acids were detected in the urine of both TR- and normal rats, with an average 3-fold greater level found in the urine of TR- animals. Biliary metabolic profiles revealed a delay in the secretion of troglitazone sulfate and troglitazone glucuronide in TR- rats over the first 2- and 4-h periods, respectively. These results demonstrate the role of multidrug resistant associated protein-2 in biliary secretion of troglitazone glucuronide and troglitazone sulfate and suggest the presence of compensatory mechanisms responsible for transport of troglitazone metabolites and bilirubin-glucuronide at the basolateral and canalicular sites of hepatocytes.

A patient pathway to renal replacement therapy: implementation in the progressive renal insufficiency population

Care paths and patient pathways are collaborative interdisciplinary tools developed to provide quality care. One goal in progressive renal insufficiency (PRI) care is to provide patients and family members with relevant and timely information to help them cope with medical therapy and lifestyle changes required to slow the progression of renal insufficiency. At Halton Healthcare Services, clinical and patient pathways have been widely used with success. Recognizing the potential benefits of a patient pathway for the PRI population, our interdisciplinary team developed a pathway that outlines the journey to renal replacement therapy. The pathway provides the patient with some insight into the future, as their disease process continues to have impact on their life. Reviewed by a patient within our PRI program during the development process, we have tailored this pathway to meet the needs of this unique population. We predict this patient pathway will have positive impact on the patient's understanding of the role of the PRI clinic and the partnership between the team members, the patient, and the family.

Chromophore-enhanced 805 nm laser therapy for gastrointestinal neoplasia

BACKGROUND

A new technique of 805 nm semiconductor diode laser-tissue interaction potentiation using indocyanine green (ICG) as an exogenous chromophore has been assessed for use in the palliation of advanced gastrointestinal malignancy.

MATERIALS AND METHODS

The tissue effects of ICG potentiated 805 nm laser were assessed both in-vivo using rat stomach and colon, and in vitro using normal and neoplastic human gastric and colonic mucosa.

RESULTS

Intravenous ICG did not potentiate the laser-tissue effects of the 805 nm laser in in-vivo studies. Local techniques of ICG application (submucosal injection +/- surface painting of 0.1% ICG solution) enhanced the total depth and diameter of laser induced thermal injury in all in-vitro tissues. Without ICG enhancement thermal tissue injury was minimal in normal gastric and colonic mucosa.

CONCLUSION

Local techniques of ICG application enhance laser induced thermal injury in normal and neoplastic gastric and colonic mucosa. This may permit targeting of 805 nm laser-tissue effects with minimal collateral damage during endoscopic laser palliation of advanced gastrointestinal malignancy.

Long-term health and predictors of survival for hyperthyroid cats treated with iodine 131

Two hundred thirty-one cats treated with radioactive iodine at the Texas Veterinary Medical Teaching Hospital were followed for a median of 25 months by means of an ambidirectional (prospective, retrospective) cohort study design. Cox proportional hazards models were used to determine predictors of survival based on data at the time of hyperthyroid diagnosis (collected retrospectively) and found that only age at diagnosis and sex of the cat were predictors of survival. Increasing age (for each year of age, relative risk [RR] = 1.2, 95% confidence interval [CI] = 1.1-1.3) and being male (RR = 0.68, 95% CI = 0.5-0.9) increased likelihood of death. Tables predicting survival after diagnosis and treatment of hyperthyroidism for various age and sex combinations were created. In addition, Cox proportional hazard models were run with all data available at the end of the study (collected retrospectively and prospectively) including number and type of major health problems reported at the time of death or censoring. In this model, significant factors were age at diagnosis, sex, and either type of major health problem or number of health problems. Cats with renal disease or cancer were more likely not to survive and increasing from none to 2 health problems also decreased survival. Renal problems and cancer were the most common health problems at the time of death or censoring. This study provides estimates of duration of survival for cats successfully treated for hyperthyroidism with radioactive iodine, which can be useful in assisting with client treatment decisions.

Integrated sample collection and handling for drug discovery bioanalysis

An integrated sample handling process for drug discovery bioanalysis is described. The streamlining of study design, sample collection and automatic bioanalytical sample processing is demonstrated. Specific details for the entire procedure regarding the time saved, ease of automation and integration are defined. Details of sample handling involved a sample collection map, sample collection formatting and volume, dilution schemes for high concentration samples, choice of biological fluid and evaluating the capabilities of two liquid-handling workstations. Numerous comparisons were conducted between the new approaches and the conventional sample handling approaches. The precision and accuracy obtained from the new integrated sample handling process were comparable to those obtained from a conventional approach, as were pharmacokinetic profiles and parameters. This new sampling process greatly improved the efficiency of drug discovery bioanalysis. The integration of pre-clinical protocol design, sample collection and bioanalysis processes was also achieved.

Three amino acid residues determine selective binding of FK506-binding protein 12.6 to the cardiac ryanodine receptor

FK506-binding protein (FKBP12) has been found to be associated with the skeletal muscle ryanodine receptor (RyR1) (calcium release channel), whereas FKBP12.6, a novel isoform of FKBP, is selectively associated with the cardiac ryanodine receptor (RyR2). For both RyRs, the stoichiometry is 4 FKBP/RyR. Although FKBP12.6 differs from FKBP12 by only 18 of 108 amino acids, FKBP12.6 selectively binds to RyR2 and exchanges with bound FKBP12.6 of RyR2, whereas both FKBP isoforms bind to RyR1 and exchange with bound FKBP12 of RyR1. To assess the amino acid residues of FKBP12.6 that are critical for selective binding to RyR2, the residues of FKBP12.6 that differ with FKBP12 were mutated to the respective residues of FKBP12. RyR2 of cardiac sarcoplasmic reticulum, prelabeled by exchange with [35S]FKBP12.6, was used as assay system for binding/exchange with the mutants. The triple mutant (Q31E/N32D/F59W) of FKBP12.6 was found to lack selective binding to the cardiac RyR2, comparable with that of FKBP12.0. In complementary studies, mutations of FKBP12 to the three critical amino acids of FKBP12.6, conferred selective binding to RyR2. Each of the FKBP12.6 and FKBP12 mutants retained binding to the skeletal muscle RyR1. We conclude that three amino acid residues (Gln31, Asn32, and Phe59) of human FKBP12.6 account for the selective binding to cardiac RyR2.

An important role for major histocompatibility complex class I-restricted T cells, and a limited role for gamma interferon, in protection of mice against lethal herpes simplex virus infection

Herpes simplex virus (HSV) inhibits major histocompatibility complex (MHC) class I expression in infected cells and does so much more efficiently in human cells than in murine cells. Given this difference, if MHC class I-restricted T cells do not play an important role in protection of mice from HSV, an important role for these cells in humans would be unlikely. However, the contribution of MHC class I-restricted T cells to the control of HSV infection in mice remains unclear. Further, the mechanisms by which these cells may act to control infection, particularly in the nervous system, are not well understood, though a role for gamma interferon (IFN-gamma) has been proposed. To address the roles of MHC class I and of IFN-gamma, C57BL/6 mice deficient in MHC class I expression (beta2 microglobulin knockout [beta2KO] mice), in IFN-gamma expression (IFN-gammaKO mice), or in both (IFN-gammaKO/beta2KO mice) were infected with HSV by footpad inoculation. beta2KO mice were markedly compromised in their ability to control infection, as indicated by increased lethality and higher concentrations of virus in the feet and spinal ganglia. In contrast, IFN-gamma appeared to play at most a limited role in viral clearance. The results suggest that MHC class I-restricted T cells play an important role in protection of mice against neuroinvasive HSV infection and do so largely by mechanisms other than the production of IFN-gamma.

Retrospective report on the effectiveness of a polyurethane football helmet cover on the repeated occurrence of cerebral concussions

This report reviews the literature and unpublished data and presents survey results related to the use of a polyurethane football helmet cover. Two hundred forty-five individuals, identified by the helmet manufacturer as having purchased at least one device, were sent a survey after the 1992, 1993, and 1994 football seasons; 155 (63.3%) of the surveys were returned. The questionnaire, designed to be completed by the athlete, required a detailed history of concussions occurring both prior to and during the period the device was used. Individuals used the device as a result of having incurred at least one concussion. Rates of concussion reoccurrence while the device was worn were grouped by the number of previous concussions (1, 2, 3, or 4+) that occurred over a 4year period prior to use of the device. The rate of concussion reoccurrence was 2.4%, 7.3%, 15.8%, and 33.3%, respectively, over a 4-year period. The range appeared to reflect a parallel relationship between pre- and post-device concussion experiences: the more concussions experienced prior to adopting the device, the higher the rate of concussion reoccurrence while using the device. The natural history of repeated occurrences of concussive events may not be affected by the use of a polyurethane football helmet cover. We suggest that such a device not be routinely used prophylactically, but instead be reserved for individuals with 1 to 2 prior concussion injuries. However, at this time, we neither recommend nor discommend the device.

Efficacy of 24-hour shifts: prepared or impaired? A prospective study

BACKGROUND

The effect of duty duration on performances is unknown. In a prospective cohort study model using repeated measures, we evaluated the effect of shift length on a battery of neuropsychologic performance indicators using our flight program as the test site.

METHODS

Flight nurses completing 24- and 12-hour shifts were tested on memory, attention, reasoning, motor, and speed measures. Ratings of stress, fatigue, sleep quality, and logged amount of work and sleep were evaluated from personal journals kept for this purpose. Data were analyzed by linear regression and repeated measures multivariate analysis of variance (MANOVA) and analysis of variance (ANOVA). Clinical significance was set at P < 0.05.

RESULTS

Fifteen subjects completed the testing and evaluation process. Neuropsychologic testing demonstrated that performance was not predicted by shift length, time of shift (day versus night), amount or quality of sleep before or during shift, or fatigue ratings. Age, gender, and education did not mediate shift length/test performance relationships. Uninterrupted sleep, stress ratings, and number of flights per shift modestly reduced some test scores. Predictably, repeated testings resulted in practice effects that reduced analysis power. We found that 24-hour shifts per se do not result in a cognitive decline compared with 12-hour shifts. Inconsistent sleep, number of flights, and the stressfulness of flights may have greater impact.