Traditional plant functional groups explain variation in economic but not size-related traits across the tundra biome.

AIM: Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits. LOCATION: Tundra biome. TIME PERIOD: Data collected between 1964 and 2016. MAJOR TAXA STUDIED: 295 tundra vascular plant species. METHODS: We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits. RESULTS: Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression. MAIN CONCLUSIONS: Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra vegetation change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insights for ecological prediction and modelling.

Priority effects transcend scales and disciplines in biology.

Although primarily studied through the lens of community ecology, phenomena consistent with priority effects appear to be widespread across many different scenarios spanning a broad range of spatial, temporal, and biological scales. However, communication between these research fields is inconsistent and has resulted in a fragmented co-citation landscape, likely due to the diversity of terms used to refer to priority effects across these fields. We review these related terms, and the biological contexts in which they are used, to facilitate greater cross-disciplinary cohesion in research on priority effects. In breaking down these semantic barriers, we aim to provide a framework to better understand the conditions and mechanisms of priority effects, and their consequences across spatial and temporal scales.

Effect of cilobradine in cats with a first episode of congestive heart failure due to primary cardiomyopathy.

INTRODUCTION: Heart rate (HR) is often elevated in cats with cardiomyopathies (CMPs). Pharmacologic modulation of HR may reduce cardiac morbidity and mortality. OBJECTIVES: To investigate the effects of cilobradine vs. placebo, regarding time to cardiac mortality or morbidity in cats with first episode of congestive heart failure (CHF) due to primary CMP. ANIMALS: Three hundred and sixty-seven client-owned cats with primary CMP that had presented with a first episode of CHF at 50 centers in Europe. Per-protocol population comprised 193 cats (n = 89 cilobradine, n = 104 placebo). An interim analysis for futility was planned. METHODS: Prospective, randomized, placebo-controlled, double-blinded, multicenter clinical trial. Primary outcome variable was the time to a composite of cardiac mortality or cardiac morbidity. RESULTS: Median time to primary outcome was 84 days (95% confidence interval [CI]: 63-219 days) in the cilobradine group (CG) and 203 days in the placebo group (95% CI: 145-377 days) with observed hazard ratio of 1.44, indicating a higher hazard for the CG (P = 0.057). Mean HR was 28 beats per minute (bpm) lower at Day 7 (P < 0.0001) and remained 29 bpm lower at Day 360 (P = 0.026) in the CG than that in the placebo group. Although the number of adverse events did not differ, there were more serious adverse events in the CG. CONCLUSIONS: Heart rate reduction by cilobradine in cats with a first episode of CHF due to primary CMP did not reduce cardiac mortality and morbidity.

Effect of pimobendan or benazepril hydrochloride on survival times in dogs with congestive heart failure caused by naturally occurring myxomatous mitral valve disease: the QUEST study.

BACKGROUND: Myxomatous mitral valve disease (MMVD) continues to be an important cause of morbidity and mortality in geriatric dogs despite conventional therapy. HYPOTHESIS: Pimobendan in addition to conventional therapy will extend time to sudden cardiac death, euthanasia for cardiac reasons, or treatment failure when compared with conventional therapy plus benazepril in dogs with congestive heart failure (CHF) attributable to MMVD. ANIMALS: Two hundred and sixty client-owned dogs in CHF caused by MMVD were recruited from 28 centers in Europe, Canada, and Australia. METHODS: A prospective single-blinded study with dogs randomized to PO receive pimobendan (0.4-0.6 mg/kg/d) or benazepril hydrochloride (0.25-1.0 mg/kg/d). The primary endpoint was a composite of cardiac death, euthanized for heart failure, or treatment failure. RESULTS: Eight dogs were excluded from analysis. One hundred and twenty-four dogs were randomized to pimobendan and 128 to benazepril. One hundred and ninety dogs reached the primary endpoint; the median time was 188 days (267 days for pimobendan, 140 days for benazepril hazard ratio = 0.688, 95% confidence limits [CL]=0.516-0.916, P= .0099). The benefit of pimobendan persisted after adjusting for all baseline variables. A longer time to reach the endpoint was also associated with being a Cavalier King Charles Spaniel, requiring a lower furosemide dose, and having a higher creatinine concentration. Increases in several indicators of cardiac enlargement (left atrial to aortic root ratio, vertebral heart scale, and percentage increase in left ventricular internal diameter in systole) were associated with a shorter time to endpoint, as was a worse tolerance for exercise. CONCLUSIONS AND CLINICAL IMPORTANCE: Pimobendan plus conventional therapy prolongs time to sudden death, euthanasia for cardiac reasons, or treatment failure in dogs with CHF caused by MMVD compared with benazepril plus conventional therapy.

Heart failure is common in diabetic cats: findings from a retrospective case-controlled study in first-opinion practice.

OBJECTIVES: To study the prognosis and cause of death in cats with diabetes mellitus. METHODS: Twenty consecutive cases of feline diabetes mellitus diagnosed in first-opinion practice were followed. Three control cats, without diabetes, were matched to each case of diabetes; these were also followed. RESULTS: One Somali cat with diabetes could not be matched, so complete data analysis considered only 19 diabetics and 57 matched controls. Death occurred in 14 of 20 diabetics and 23 of 57 controls although one control cat was eventually lost to follow-up. Heart disease and heart failure led to death in six diabetic cats. One of these was the non-matched Somali; nevertheless, the death rate from heart disease in the diabetics was five of 19 compared with two of 57 in controls. The relative risk of heart failure in diabetic cats was 10.4 times that of the controls; this difference in rates was statistically significant. Survival amongst diabetics was significantly worse than for controls. For the control cats median survival was 718 days after the index visit, whereas for the diabetic cases median survival was 385 days after diagnosis. CLINICAL SIGNIFICANCE: Heart disease and failure are common in diabetic cats. This observation deserves further attention.

Rapid assessment with physical examination in dyspnoeic cats: the RAPID CAT study.

OBJECTIVES: To determine the underlying disease prevalence in acute feline dyspnoea and to examine whether historical and clinical examination findings can differentiate between acute cardiac and non-cardiac dyspnoea in cats in primary practice. MATERIALS AND METHODS: We prospectively enrolled cats presenting with dyspnoea for the first time to primary practice between June 1, 2011 and October 31, 2016. We collected signalment, historical and clinical data at presentation using a standard form. Cases were investigated by primary clinicians, and the final diagnosis was confirmed by the authors. Records lacking critical data were excluded. Relationships between historical or clinical variables and dyspnoea aetiology were examined. Diagnostic test performance analyses were used to find optimal cut-off values for select historical or clinical variables that could differentiate cardiac and non-cardiac dyspnoea. RESULTS: Participants included 108 cats. A definitive diagnosis was reached in 92 cases; 60 were cardiac (65%), 15 respiratory (16%), 10 neoplastic (11%) and 7 traumatic (8%). Of cats with cardiac dyspnoea, 25% had a history of cough. A gallop sound, rectal temperature less than 37·5°C, heart rate of greater than 200 bpm and respiratory rate greater than 80 per minute were all useful to predict cardiac-associated dyspnoea. A triage algorithm using these findings in combination was designed to optimise the rapid diagnosis of probable cardiac dyspnoea. CLINICAL SIGNIFICANCE: Dyspnoeic cats presenting in practice with hypothermia, tachycardia, gallop sounds or profound tachypnoea are likely to have a cardiac cause underlying their dyspnoea. Although diagnosis requires confirmation, clinicians may be able to stratify risk and prioritise further investigation based on these findings.

Heart failure in two West Highland white terriers caused by congenital angiomatous cardiac anomaly.

The paper describes the clinical and pathological characteristics of an unusual cystic congenital cardiac anomaly that caused clinical signs of congestive heart failure, respiratory distress and cardiac arrhythmias in two West Highland white terrier puppies. In both dogs a definitive diagnosis was made postmortem.

Heart rate turbulence after ventricular premature beats in healthy Doberman pinschers and those with dilated cardiomyopathy.

OBJECTIVES: To describe the measurement of heart rate turbulence (HRT) after ventricular premature beats and compare HRT in healthy Doberman pinschers and those with dilated cardiomyopathy (DCM), with and without congestive heart failure (CHF). ANIMALS: Sixty-five client-owned Dobermans: 20 healthy (NORMAL), 31 with preclinical DCM and 14 with DCM and CHF (DCM + CHF). METHODS: A retrospective study of data retrieved from clinical records and ambulatory ECG (Holter) archives, including data collected previously for a large-scale prospective study of Dobermans with preclinical DCM. Holter data were reanalysed quantitatively, including conventional time-domain heart rate variability and the HRT parameters turbulence onset and turbulence slope. RESULTS: Heart rate turbulence could be measured in 58/65 dogs. Six Holter recordings had inadequate ventricular premature contractions (VPCs) and one exhibited VPCs too similar to sinus morphology. Heart rate turbulence parameter, turbulence onset, was significantly reduced in DCM dogs, whereas conventional heart rate variability measures were not. Heart rate variability and HRT markers were reduced in DCM + CHF dogs as expected. CONCLUSIONS: Heart rate turbulence can be measured from the majority of good quality standard canine 24-hour Holter recordings with >5 VPCs. Turbulence onset is significantly reduced in Dobermans with preclinical DCM which indicates vagal withdrawal early in the course of disease. Heart rate turbulence is a powerful prognostic indicator in human cardiac disease which can be measured from standard 24-hour ambulatory ECG (Holter) recordings using appropriate computer software. Further studies are warranted to assess whether HRT may be of prognostic value in dogs with preclinical DCM and in other canine cardiac disease.

Non-invasive real-time measurements of cardiac vagal tone in dogs with cardiac disease.

In dogs with spontaneous heart disease, an electronically generated measurement of cardiac vagal tone, the cardiac index of parasympathetic activity, was a sensitive, simple and inexpensive measure of the severity of heart failure. Dogs with cardiac disease and an index score less than 3 were at 15.8 (95 per cent confidence interval 2.9 to 87.2) times the risk of dying within a year than those with a score of 3 and over. The measurement of the index provided an objective and reliable beat-by-beat measurement of cardiac vagal tone, which was prognostically useful in dogs with heart disease.

Hypoglycaemic bradycardia and circulatory collapse in a dog and a cat.

Hypoglycaemia was accompanied by sinus bradycardia and circulatory collapse in a dog and a cat. In each case, when the hypoglycaemia was corrected by intravenous infusion of a glucose solution the bradycardia and circulatory failure were soon abolished, indicating that these abnormalities were caused by the hypoglycaemia. Similar observations have been made in human patients. To the author's knowledge, this is the first report documenting hypoglycaemic bradycardia in veterinary medicine.

Heparin versus normal saline as a peripheral line flush in maintenance of intermittent intravenous lines in obstetric patients.

OBJECTIVE: To compare heparin sodium (100 United States Pharmacopeia U/mL) with 0.9% sodium chloride for use in the maintenance of intermittent intravenous (IV) devices during pregnancy. METHODS: Women at 26-34 weeks' gestation who required serial phlebotomy were assigned randomly to heparin or normal saline flush, administered in a double-blind fashion. Catheter sites were examined and flushed with the study solution at least once every 6 hours. Partial thromboplastin times (PTTs) were measured at catheter insertion and 48 hours later. Statistical analysis was performed with Student t test, Mann-Whitney U test, Fisher exact test, log-rank, and X2 analysis, as appropriate. RESULTS: There was a significant increase in catheter patency rate at 48 and 72 hours in the heparin group (26 of 31 versus 17 of 33, and 21 of 31 versus nine of 33, respectively; P < .01). In addition, there was a significantly lower rate of catheter complications in the heparin group (four of 31 versus 13 of 33; P < .01). There were no differences in PTTs. CONCLUSION: During pregnancy, dilute heparin flush to maintain patency of intermittent IV site devices results in the following: a greater catheter patency rate at 48 and 72 hours after insertion of the catheter, a lower rate of catheter complications requiring therapy, and no alteration in PTT.

Effects of fatty acids on the growth and composition of Malassezia pachydermatis and their relevance to canine otitis externa.

Malassezia pachydermatis is one of the many infective agents involved in canine otitis externa. Two major phenotypes (large and small colony types), which had different fatty acid compositions, were found among strains of M pachydermatis isolated from canine ears or skin. The large-colony type contained palmitic, stearic, oleic and linoleic acids, whereas the small-colony type contained myristic, palmitic, stearic, linoleic acids and five other unidentified fatty acids. Exogenous saturated fatty acids in the medium had no effect on the growth of a large colony strain but oleic and linoleic acids were mycostatic. Adding fatty acids to the medium changed the fatty acid composition of the strain. Saturated fatty acids were incorporated as such into the cell, but the unsaturated fatty acids caused complex changes in composition, including the appearance of a new fatty acid. It is suggested that these changes in the fatty acid composition of M pachydermatis could explain the mycostatic effect of unsaturated fatty acids like oleic and linoleic acids at least in vitro.

Effect of illness not associated with the thyroid gland on serum total and free thyroxine concentrations in cats.

OBJECTIVE: To determine circulating concentrations and fate of total and free thyroxine (T4) in cats with various illnesses not associated with the thyroid glands (nonthyroidal illnesses). DESIGN: Prospective study. ANIMALS: 98 cats with nonthyroidal illness and 50 clinically normal cats. PROCEDURE: Serum total T4 concentrations were measured by radioimmunoassay, and serum free T4 concentrations were measured by direct equilibrium dialysis. Free T4 fraction was calculated from these 2 values. RESULTS: Serum total T4 concentrations were significantly (P < 0.001) lower in sick cats (mean +/- SD, 17.18 +/- 8.14 nmol/L), compared with healthy cats (mean +/- SD, 26.00 +/- 7.62 nmol/L). Serum total T4 concentrations were inversely correlated with mortality. Differences in serum free T4 concentrations in sick cats (mean +/- SD, 27.70 +/- 13.53 pmol/L), compared with healthy cats (mean +/- SD, 24.79 +/- 8.33 pmol/L), were not significant. A few sick cats had serum free T4 concentrations greater than the reference range. Calculated free T4 fraction was significantly (P < 0.001) greater in sick cats (mean +/- SD, 0.24 +/- 0.30%), compared with healthy cats (mean +/- SD, 0.10 +/- 0.06%). CLINICAL IMPLICATIONS: Euthyroidism is maintained in sick cats, despite low serum total T4 concentrations. Measurement of serum total T4 concentrations is a valuable prognostic indicator. Serum free T4 concentrations should be used cautiously as a sole diagnostic criterion for confirmation of hyperthyroidism.

An evaluation of tympanometry, otoscopy and palpation for assessment of the canine tympanic membrane.

Three techniques for the assessment of the integrity of the canine tympanic membrane were evaluated experimentally. Tympanometry, an objective technique, was shown to be very accurate for the evaluation of the integrity of the ear drum. Otoscopic examination by experienced personnel was shown to be moderately accurate under controlled conditions when the external ear canal was not inflammed. However, under field conditions when otitis externa was present, visual inspection of the tympanic membrane was seldom possible even after lavage of the ear. Palpation of the tympanic membrane with a blunt probe was shown to be very inaccurate and led to rupture of the tympanic membrane in a high proportion of cases. These results imply that two widely used techniques for the examination of the canine tympanic membrane are unsatisfactory. Furthermore, they suggest that previous reports of the prevalence of ear drum perforations in dogs may need reappraisal. Tympanometry is a non-invasive, objective and practical technique for the assessment of ear drum integrity which is worthy of further evaluation.

Inflammatory middle ear disease of the dog: the clinical and pathological features of cholesteatoma, a complication of otitis media.

During a study of inflammatory middle ear disease in the dog cholesteatoma was found to accompany otitis media in seven of the 62 ears examined (11 per cent). The clinical, radiological and pathological findings in these animals imply that cholesteatoma in the dog is an aggressive lesion which must be differentiated from uncomplicated otitis media.

Inflammatory middle ear disease of the dog: the pathology of otitis media.

Inflammation within the middle ear cavity was recognised in 62 of the ears of 42 dogs with chronic otitis externa and otitis media, after biopsy or necropsy of the middle ear. The pathological changes in the middle ear resembled those reported in other species or after the experimental induction of otitis media in dogs. Perforations in the tympanic membrane were rarely found; on the contrary, the membrane was often thickened. However, the question of whether a perforation in the tympanic membrane must occur before otitis externa can extend to otitis media was not resolved.

Consistency of results from the Vettest 8008 clinical biochemistry analyser.

Findings are presented on the precision of a clinical biochemistry analyser designed specifically for veterinary use. Twenty biochemical analytes have been examined in detail for variation within and between runs. The results indicate that the analyser can provide high precision for all the analytes with the possible exception of calcium, and suggest that the instrument can be used with confidence in the practice laboratory to aid diagnosis and to monitor biochemical changes in animals receiving treatment.

Neoplasia involving the middle ear cavity of dogs.

Eleven cases of neoplasia which involved the middle ear cavity of dogs are recorded. Eight of the tumours originated in the external ear canal and comprised four adnexal tumours, one squamous papilloma and three adenocarcinomas of the ceruminous glands. Papillary adenomas were recognised within the middle ear cavity of two dogs. In one animal the precise origin of an anaplastic carcinoma involving the middle ear could not be determined. Only five of the tumours were amendable to surgical excision and four dogs survived for more than eight months after surgery.

Tachyarrhythmia in a St Bernard dog.

SUMMARY: A young St Bernard dog was referred on three separate occasions for investigation of dyspnea and exercise intolerance. Electrocardiography was performed on each occasion and showed various forms of supraventricular tachycardia with aberrant conduction. Echocardiography showed a progressive decrease in systolic function and thoracic radiographs showed progressive cardiomegaly. The arrhythmia responded rapidly to treatment with propanolol.

Investigation of heart rate variability in a dog with upper respiratory tract obstruction.

An eight-year-old bull mastiff presented with respiratory obstruction caused by a tumour dorsolateral to the larynx. Removal of the tumour was attempted but the dog died. A novel noninvasive measurement of heart rate variability and cardiac parasympathetic activity, recorded real-time from an electrocardiograph signal, was used to investigate cardiac rhythm in the dog. A simultaneous record of heart rate and cardiac parasympathetic activity showed severe sinus arrhythmia caused by the parasympathetic tone, in which the inspiratory heart rate exceeded 140 beats per minute (bpm) and the expiratory heart rate fell to below 60 bpm. The extent of respiratory modulation of the cardiac parasympathetic activity (vagal tone) has not been reported before using this technique on-line in a conscious, freely-behaving and spontaneously breathing animal. Non-invasive measurements of cardiac parasympathetic tone show great potential for the assessment of animals with systemic and cardiac disease including cardiac failure.