Pre-operative stress in dogs - a preliminary investigation of behavior and heart rate variability in healthy hospitalized dogs

OBJECTIVE: To assess pre-operative behavioral and physiological characteristics of healthy dogs hospitalized for elective surgery. STUDY DESIGN: Open clinical observational study. ANIMALS: Forty-one bitches hospitalized for elective ovariohysterectomy. METHODS: While undisturbed in a hospital cage, the behavior of the dog was recorded using a video camera and recorder. From the video recordings, various behavioral variables were registered. Simultaneous measurements were made on heart rates and heart rate variability (HRV) by use of an ambulatory electrocardiogram. In addition, the dog's response to human approach was noted. RESULTS: Different behavioral patterns were found in the dogs studied. Thirteen individuals were regarded as highly active, and were seen to bark or howl, manipulate the environment or attempt to flee vigorously. In 13 dogs (passive dogs) none of these activities occurred. Panting and displacement behaviors, such as snout licking, were observed in nearly all the animals monitored. In general, heart rates were higher and HRV lower with the most active individuals; however, the presence of physiological arousal could not be excluded in two animals with passive behaviors. To some extent, the behavior of the dog while undisturbed in the cage was reflected in the responses to a person entering the cage. CONCLUSIONS AND CLINICAL RELEVANCE: The different individual responses detected in this study raise an important question concerning their role and existence throughout the entire peri-operative period, especially during the post-anesthetic recovery phase when behavioral characteristics are commonly used to assess patient welfare. The results also emphasize the need for further investigations to explore the effects of pre-operative stressors on canine surgical patients, and the factors contributing to them.     

The effects of L-659,066, a peripheral alpha2-adrenoceptor antagonist, on dexmedetomidine-induced sedation and bradycardia in dogs

Objective  To investigate the influence of L-659,066, a peripheral α2-adrenoceptor antagonist, on dexmedetomidine-induced sedation and reduction in pulse rate (PR) in dogs.
Study design  Randomized, cross-over.
Animals  Six healthy laboratory Beagles.
Methods  All animals received dexmedetomidine (5 μg kg⁻¹ IV, DEX) alone or in combination with L-659,066 (250 μg kg⁻¹ IV, DEX + L) with a 7-day rest period between treatments. Sedation was assessed using a composite sedation score and PRs were recorded. Atipamezole (50 μg kg⁻¹ IM, ATI) was administered to reverse the sedation. Overnight Holter-monitoring was carried out to obtain a minimum heart rate (MHR) at rest.
Results  Bioequivalence was shown for clinical sedation between DEX and DEX + L. Heart rate was significantly higher with DEX + L during the period of sedation. Bioequivalence was demonstrated between MHR and PR in the DEX + L group during the period of sedation. Recoveries after ATI were uneventful.
Conclusions  L-659,066 did not affect the quality of dexmedetomidine-induced sedation whilst it attenuated the reduction in PR. Thus, L-659,066 could prove a useful adjunct to reduce the peripheral cardiovascular effects attributed to dexmedetomidine in dogs.
Clinical relevance  The clinical safety of α2-adrenoceptor agonists could be markedly improved with less peripheral cardiovascular effects.     

Opinions of Finnish small animal owners about surgery and pain management in small animals

Objectives : To examine the opinions among small animal owners regarding the management of pain and surgery in small animals. Methods : A questionnaire was presented to 800 owners of dogs or cats who visited one of the four participating clinics in Finland in February 2006. Results : A total of 482 owners completed the questionnaire (60·3 per cent response rate); 90 per cent of the respondents were female. Owners classified surgical procedures (for example, fracture repair, skin tumour removal and neutering) as more painful than medical conditions (otitis externa and lameness). In addition, owners disagreed most with statements that they had received sufficient information on the appropriate methods of management of animal pain and that the recognition of animal pain is easy. With respect to surgical procedures, owners expressed greatest concern in relation to the animal experiencing fear or anxiety during hospitalisation and the presence of postoperative pain. Clinical Significance : The animal owners had concerns about the presence and management of animal pain, fear and anxiety. Knowledge of these animal owner opinions could aid veterinary practitioners when communicating with their clients on medical and surgical patient management. Furthermore, studies are merited to clearly define how best to successfully respond to these owner attitudes.     

Pituitary adenoma predisposition caused by germline mutations in the AIP gene

Pituitary adenomas are common in the general population, and understanding their molecular basis is of great interest. Combining chip-based technologies with genealogy data, we identified germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene in individuals with pituitary adenoma predisposition (PAP). AIP acts in cytoplasmic retention of the latent form of the aryl hydrocarbon receptor and also has other functions. In a population-based series from Northern Finland, two AIP mutations account for 16% of all patients diagnosed with pituitary adenomas secreting growth hormone and for 40% of the subset of patients who were diagnosed when they were younger than 35 years of age. Typically, PAP patients do not display a strong family history of pituitary adenoma; thus, AIP is an example of a low-penetrance tumor susceptibility gene.     

Endophytic fungi in Siberian larch (Larix sibirica) needles

Endophytic fungi were isolated from surface‐sterilized needles of the Siberian larch. Samples were collected from a native growing site of the Siberian larch in north‐western Russia and from sites in Russia, Finland and Iceland where the Siberian larch has been introduced. The isolated fungi were classified to operational taxonomic units (OTUs) using colony morphology and molecular characteristics. Needle colonization rates were 50–99% and in total 79 OTUs were found. There were five common OTUs, which covered 86.2% of all isolates. The most common OTU lacked from the youngest plantations in Finland (Solböle) and in Iceland (Kjarnaskógur). The highest similarity in regard to the frequency of OTUs occurred among the stands established long ago in Finland, and the UPGMA clustering using similarity indices separated the seven stands into two major groups.     

Cardiopulmonary effects of a two hour medetomidine infusion and its antagonism by atipamezole in horses and ponies

The cardiopulmonary effects of an intravenous (iv) medetomidine injection (5 μg/kg) followed 5 min later by its infusion at 3.5 μg/kg/h for 115 rnin were studied in 9 horses and ponies. Five minutes after the end of infusion 60 μg/kg atipamezole were given. Physiological data during infusion were compared with pre-sedation values. Stroke volume was reduced significantly 5 min after initial medetomidine injection. Cardiac index was reduced significantly and systemic vascular resistance increased significantly for the first 20 min, but returned towards pre-sedation values after this time. Arterial blood pressures were reduced significantly from 30 min until the end of the procedure (minimum MAP was 102.4 ± 9.61 mmHg). Mixed venous oxygen tension was reduced significantly during the infusion. Respiratory rate fell and PaCO₂- rose significantly from 40 min onward. Other variables showed no significant changes. The horses recovered rapidly after atipamezole was injected. Arterial blood pressures remained significantly lowered, but other cardiovascular variables returned towards pre-sedation values. It is concluded that the infusion of medetomidine at 3.5 μg/kg/h causes minimum cardiopulmonary depression once the effects of an initial 5 μg/kg injection have waned, and so could prove suitable as part of an anaesthetic technique in equidae.     

Comparison of medetomidine and dexmedetomidine as premedicants in dogs undergoing propofol-isoflurane anesthesia.

OBJECTIVE: To compare 3 dose levels of medetomidine and dexmedetomidine for use as premedicants in dogs undergoing propofol-isoflurane anesthesia. ANIMALS: 6 healthy Beagles. PROCEDURE: Dogs received medetomidine or dexmedetomidine intravenously at the following dose levels: 0.4 microg of medetomidine or 0.2 microg of dexmedetomidine/kg of body weight (M0.4/D0.2), 4.0 microg of medetomidine or 2.0 microg of dexmedetomidine/kg (M4/D2), and 40 microg of medetomidine or 20 microg of dexmedetomidine/kg (M40/D20). Sedation and analgesia were scored before induction. Anesthesia was induced with propofol and maintained with isoflurane. End-tidal isoflurane concentration, heart rate, and arterial blood pressures and gases were measured. RESULTS: Degrees of sedation and analgesia were significantly affected by dose level but not drug. Combined mean end-tidal isoflurane concentration for all dose levels was higher in dogs that received medetomidine, compared with dexmedetomidine. Recovery time was significantly prolonged in dogs treated at the M40/D20 dose level, compared with the other dose levels. After induction, blood pressure decreased below reference range and heart rate increased in dogs treated at the M0.4/D0.2 dose level, whereas blood pressure was preserved in dogs treated at the M40/D20 dose level. However, dogs in these latter groups developed profound bradycardia and mild metabolic acidosis during anesthesia. Treatment at the M4/D2 dose level resulted in more stable cardiovascular effects, compared with the other dose levels. In addition, PaCO2 was similar among dose levels. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine is at least as safe and effective as medetomidine for use as a premedicant in dogs undergoing propofol-isoflurane anesthesia.     

Pines beyond the polar circle: Adaptation to stress conditions

Summary Plant populations in extreme conditions differ from those in more favorable conditions in many respects. They have developed special physiological adaptations for withstanding e.g. extreme temperatures or drought. On the other hand, low survival and fertility may cause smaller effective population sizes, which in turn influences patterns of genetic variation. Scots pine has the widest range of all pine species, extending in the north far beyond the arctic circle. Close to the tree limit, the growing season is short and survival is low. Very northern populations also have lower and more irregular male and female flowering and seed production than southern ones. The consequences of these conditions on genetic variation have been examined. All Finnish populations have similar patterns of variation at allozyme loci and nuclear DNA markers: high variation but no differentiation between populations. Northern populations seem to have slightly fewer recessive deleterious alleles than southern ones. There is, however, strong differentiation between populations with respect to adaptation to the very short growing season. In common garden experiments, northern populations cease growth and set buds much earlier and develop frost tolerance earlier than southern populations. The genetic basis for this high differentiation in bud set can be explored by using dense maps of molecular markers. The implications of these patterns of variations on conservation of genetic resources and tree breeding will be discussed.