Patterns in the transition from normal to neurosis in dogs with different typological traits in food and defensive situations

At comparison of the formation of neurosis in dogs with different typological characteristics in conditions with alimentary and pain reinforcement, a resemblance was revealed of transition from norm to the initial stage of pathology. In strong animals a development was seen of compensatory tachycardia at circular changes of conditioned activity. Weak type dogs are characterized by a lowering or full disappearance of reflexes in combination with bradycardia. The method of differentiation, allowing in situations with alimentary reinforcement to classify the tested animals according to the type of higher nervous activity and differentiate the states of "norm" and "initial stage of neurosis", proved to be effective for the analogous aims also in studies with defensive reinforcement.     

Stages in the development of neuroses in the dog and effects of preparations with antidepressive and tranquilizing properties

In modelling of neuroses, successive stages of development of this pathology were observed in dogs. The first stage is characterized by circular disturbances of conditioned activity, vegetative shifts of compensatory character and intensification of individual characteristics of behaviour. At the second stage, parallel with sharp disturbances of conditioned reflexes and with vegetative dystonia, a distortion of emotional reactions was observed in dogs. It is essential that resumption of neurotization episodes in experiments on dogs with the second stage of disease promoted a development of depressive-like states. Diazepam corrected the behavioural and vegetative shifts at the first stage of neurosis. Non-typical antidepressants eliminated the manifestation of symptoms complex of the disease, especially at prolonged treatment.     

Remodeling of the left atrium in pacing-induced atrial cardiomyopathy

Rapid atrial pacing produces atrial systolic and diastolic failure characterized by absent atrial booster pump function, increased atrial chamber stiffness, enhanced atrial conduit function, and atrial enlargement. However, the processes underlying these abnormalities are poorly understood. Therefore, we examined left atrial myocardium from dogs with rapid pacing-induced atrial failure (400 bpm for 6 weeks) and from control dogs. Western blotting was used to determine the levels of proteins involved in calcium homeostasis (SERCA 2A, phospholamban, Na⁺-Ca²⁺ exchanger). Matrix metalloproteinase (MMP) activity was measured using gelatin and casein zymography, and levels of tissue inhibitor of metalloproteinase-4 (TIMP-4) and the TIMP-4 complexed with MMPs were measured with Western blot analysis. There were no differences in SERCA 2A or Na⁺-Ca²⁺ exchanger protein levels, but phospholamban level was significantly decreased in atrial samples from rapidly paced dogs (51.2 ± 7.8 vs. 77.0 ± 10.0, p < 0.01). The activity of MMP-9 was selectively and significantly increased by 50%, and the level of complexed TIMP-4 protein was significantly decreased by 50% in samples from dogs with atrial failure. Thus, rapid pacing-induced atrial failure is associated with differential changes in MMP activity, an unchanged number of calcium pumps, and compensatory changes in the level of phospholamban.     

The Fecal Microbiome in Dogs with Acute Diarrhea and Idiopathic Inflammatory Bowel Disease

Background

Recent molecular studies have revealed a highly complex bacterial assembly in the canine intestinal tract. There is mounting evidence that microbes play an important role in the pathogenesis of acute and chronic enteropathies of dogs, including idiopathic inflammatory bowel disease (IBD). The aim of this study was to characterize the bacterial microbiota in dogs with various gastrointestinal disorders.

Methodology/Principal Findings

Fecal samples from healthy dogs (n = 32), dogs with acute non-hemorrhagic diarrhea (NHD; n = 12), dogs with acute hemorrhagic diarrhea (AHD; n = 13), and dogs with active (n = 9) and therapeutically controlled idiopathic IBD (n = 10) were analyzed by 454-pyrosequencing of the 16S rRNA gene and qPCR assays. Dogs with acute diarrhea, especially those with AHD, had the most profound alterations in their microbiome, as significant separations were observed on PCoA plots of unweighted Unifrac distances. Dogs with AHD had significant decreases in Blautia, Ruminococcaceae including Faecalibacterium, and Turicibacter spp., and significant increases in genus Sutterella and Clostridium perfringens when compared to healthy dogs. No significant separation on PCoA plots was observed for the dogs with IBD. Faecalibacterium spp. and Fusobacteria were, however, decreased in the dogs with clinically active IBD, but increased during time periods of clinically insignificant IBD, as defined by a clinical IBD activity index (CIBDAI).

Conclusions

Results of this study revealed a bacterial dysbiosis in fecal samples of dogs with various GI disorders. The observed changes in the microbiome differed between acute and chronic disease states. The bacterial groups that were commonly decreased during diarrhea are considered to be important short-chain fatty acid producers and may be important for canine intestinal health. Future studies should correlate these observed phylogenetic differences with functional changes in the intestinal microbiome of dogs with defined disease phenotypes.     

The typological characteristics of higher nervous activity in dogs and the maxima of the cross-correlation function between the electrical activities of the frontal cortex and the brain limbic systems]

Electrical activity of the frontal cortex, dorsal hippocampus, basolateral amygdala and lateral hypothalamus was recorded in eight dogs with chronically implanted electrodes. Mean values of the maxima of crosscorrelation function (MCCF) between electrical potentials in the theta, alpha and beta-2 ranges were used as a basis for assessment of conditions for interaction between these structures. Typological features of the higher nervous activity were assessed by the animal performance under conditions of free choice of the reinforcement mode of a conditioned stimulus: either high probable but of low alimentary quality or with low probability but more valuable. The mean MCCF values in the theta range were higher than in the other ranges. The brain structure which had the high MCCF in the theta-range, at least, with two of the structures under study was considered as "dominant". It was shown that hippocampus was the dominant structure for melancholic dogs, the frontal cortex was in phlegmatics. The hypothalamus was shown to be the "dominant structure" in both sanguine and choleric animals, but, for the most part, its activity was correlated with different structures. Thus, conditions for interaction between the frontal cortex, hippocampus, amygdala and hypothalamus seem to be an important factor, which determines typological features of the higher nervous activity of dogs.     

Individual behavior characteristics of dogs in conflict between the probability and the quality of reinforcement

In experiments on dogs with equiprobable right and left reinforcements in the choice of feeder in conditions of free behaviour, direct correlation was found between the strength of the nervous system and the strategy of dogs behaviour. The dogs of strong type, despite the difference in equilibration and lability, manifested one, similar strategy of behaviour with dominating preferences, definite and goal-directed actions; the dogs of the weak type displayed another strategy, characterized by uncertainty, permanent hesitations in choice reaction. In situation of competition of probability and value of reinforcement, some different aspects of animals typology appeared, presumably connected with individual characteristics of functioning of four brain structures as a basis of types of higher nervous activity (frontal cortex, hippocampus, amygdala, hypothalamus). Behaviour of choleric and flegmatic was oriented to a high probability of events and that of sanguinic and melancholic--to a low one. Thus, "informational" and "motivational" factors of behaviour organization are connected with interaction of specialized brain macrostructures, and properties of this interaction become apparent in animals typology.     

Estimates of the efficacy of the local protection of dogs against ionizing radiation

The possibility of prognosis of survival of dogs subjected to acute nonuniform irradiation leading to haemopoietic radiation sickness has been demonstrated. The prognosis is based on the "equal dose" concept that is implemented together with the dose dependence of the bone marrow haemopoiesis activity. The estimates of the consequences of irradiation of dogs, with certain body parts being shielded, have shown a good correlation between the calculation results and the experimental data.     

Characterization of three regulatory states of the striated muscle thin filament

The troponin-tropomyosin-linked regulation of striated muscle contraction occurs through allosteric control by both Ca(2+) and myosin. The thin filament fluctuates between two extreme states: the inactive "off" state and the active "on" state. Intermediate states have been proposed from structural studies and transient kinetic measurements. However, in contrast to the well-characterised, on and off states, the mechanochemical properties of the intermediate states are much less well understood because of the instability of those states. In the present study, we have characterized a myosin-induced intermediate that is stabilized by cross-linking myosin motor domains (S1) to actin filaments (with a maximum of one S1 molecule for 50 actin monomers). A single S1 molecule is known to interact with two adjacent actin monomers. A detailed analysis revealed that thin filaments containing S1 molecules cross-linked to just one actin monomer (actin(1)-S1 complexes) are regulated with a 79% inhibition of the ATPase in the absence of Ca(2+). In contrast, filaments containing S1 molecules cross-linked at two positions, to two adjacent actin monomers (actin(2)-S1 complexes) totally lose their regulation in a highly cooperative manner. This loss of regulation was due both to an enhancement of the ATPase activity without calcium and an inhibition of the ATPase with calcium. Filaments containing actin(2)-S1 complexes, with significant ATPase activity in the absence of calcium (about 50%), did not move on a myosin-coated surface unless calcium was present. This partial uncoupling between the ATPase activity and in vitro motility in the absence of calcium demonstrates that the mechanical steps require actin-myosin contacts, which take place only in the on state and not in the off or intermediate states. These data provide new insights concerning the difference in cooperativity of Ca(2+) regulation that exists between the biochemical and mechanical cycles of the actin-myosin motor.     

Favourable effect of physical exercise on informational pathology of higher nervous activity

As a model of neurotic states induced by information overload experimental neurotic states were evoked in 13 dogs reared under conditions of partial social isolation by shortening the intertrial intervals in an alimentary conditioned reflex situation with delayed reinforcement. Both behavioural and autonomous disturbances were completely abolished in 4 of 5 dogs which were systematically exposed to muscular activity. Similar protective and therapeutic effect had the muscular exercise which formed a main component of the therapy in 59 neurotic subjects.     

Fear conditioning in humans: the influence of awareness and autonomic arousal on functional neuroanatomy

The degree to which perceptual awareness of threat stimuli and bodily states of arousal modulates neural activity associated with fear conditioning is unknown. We used functional magnetic neuroimaging (fMRI) to study healthy subjects and patients with peripheral autonomic denervation to examine how the expression of conditioning-related activity is modulated by stimulus awareness and autonomic arousal. In controls, enhanced amygdala activity was evident during conditioning to both "seen" (unmasked) and "unseen" (backward masked) stimuli, whereas insula activity was modulated by perceptual awareness of a threat stimulus. Absent peripheral autonomic arousal, in patients with autonomic denervation, was associated with decreased conditioning-related activity in insula and amygdala. The findings indicate that the expression of conditioning-related neural activity is modulated by both awareness and representations of bodily states of autonomic arousal.     

Natural 1st and 2d degree conditioned food reflexes in the dog in relation to space orientation

In three dogs formation and performance of spatial alimentary natural conditioned responses of the second order was studied when the dog had to find food preliminarily shown to it in one of the four food-distributors (psychonervous activity directed by a food image in terms proposed by I. S. Beritashvili). Characteristics of this form of behaviour were demonstrated and discussed: rapid formation, dependence of performance on the delay time, conflict between responses of the first and the second order. In the second series of the experiments food-procuring behaviour of dogs was studied under conditions of conflict between the quality (value) of alimentary reinforcement and probability of its finding in certain food-distributor. Such kind of behavior was shown to depend on the motivation level and individual characteristics of the dog. Interaction of "informational" (anterior areas of the neocortex, hippocampus) and "motivational" (nuclei of amigdalar complex, hypothalamus) cerebral structures is supposed to underlie the organization of behaviour.     

Glutamate decarboxylase and GABA transaminase activity in the mitochondrial fraction of the dog brain limbic system during postnatal development

Overall glutamate decarboxylase (GDCase) activity in the initial mitochondrial fraction of the limbic structure is found to be regionally different it increases from the moment of birth up to 1 year, the midbrain reticular formation (RF), where the enzyme activity in the mitochondrial decreases in pups aged 3 month and reincreases in 1 year old dogs being the exception. Overall GABA-transaminase (GABA-T-ase) activity reaches the "adult" level and is the highest: in the hypothalamic and hippocampal mitochondria on the 1st postnatal day; in the limbic cortex (l1 and l2 fields), amygdala and midbrain RF--on the 12-16th postnatal days. During the period from 12-16 postnatal days up to the age of 1 year GABA-T-ase activity in the dog limbic system decreases reliably.     

Colon electrical stimulation: potential use for treatment of obesity

Obesity is one of the most prevalent health problems in the United States. Current therapeutic strategies for the treatment of obesity are unsatisfactory. We hypothesized the use of colon electrical stimulation (CES) to treat obesity by inhibiting upper gastrointestinal motility. In this preliminary study, we aimed at studying the effects of CES on gastric emptying of solid, intestinal motility, and food intake in dogs. Six dogs, equipped with serosal colon electrodes and a jejunal cannula, were randomly assigned to receive sham-CES or CES during the assessment of: (i) gastric emptying of solids, (ii) postprandial intestinal motility, (iii) autonomic functions, and (iv) food intake. We found that (i) CES delayed gastric emptying of solids by 77%. Guanethidine partially blocked the inhibitory effect of CES on solid gastric emptying; (ii) CES significantly reduced intestinal contractility and the effect lasted throughout the recovery period; (iii) CES decreased vagal activity in both fasting and fed states, increased the sympathovagal balance and marginally increased sympathetic activity in the fasting state; (iv) CES resulted in a reduction of 61% in food intake. CES reduces food intake in healthy dogs and the anorexigenic effect may be attributed to its inhibitory effects on gastric emptying and intestinal motility, mediated via the autonomic mechanisms. Further studies are warranted to investigate the therapeutic potential of CES for obesity.     

Sodium-potassium pump inhibitor in the mechanism of one-kidney, one wrap hypertension in dogs.

Using ouabain sensitive 86Rb uptake by the vessel wall, we previously showed that sodium-potassium pump activity is decreased in the arteries and veins, and that the sodium-potassium pump inhibitor (SPI) is increased in the plasma of dogs with one-kidney, one wrap (1-K, 1W) hypertension, a low renin model of hypertension. We also showed in rats with a similar type of hypertension that the membrane potential of vascular smooth muscle cells in arteries is decreased, and that this decrease can be reproduced in arterial cells in arteries from normal rats by applying plasma from the hypertensive animals. One endogenous SPI in human plasma has been reported to be ouabain or its isomer. In this study, we used a newly available Dupont ouabain enzyme immunoassay kit to examine plasma and kidneys for SPI in dogs with 1-K, 1W hypertension. We also examined 1) the inhibiting activity of plasma of Na+, K(+)-ATPase obtained from normal kidneys, and 2) the Na+, K(+)-ATPase activity of the kidneys from these hypertensive animals. 1-K, 1W hypertension was produced in dogs by wrapping the left kidney in a silk bag and removing the right kidney. The removed kidney was kept at -70 degrees C till assayed. After 4 weeks of hypertension, the remaining kidney was removed and stored at -70 degrees C till assayed. Blood samples were drawn before and at weeks 3 and 4 of hypertension. Plasma levels of "ouabain" and Na+, K(+)-ATPase inhibitory activity were increased at weeks 3 and 4 of hypertension, compared to pre-hypertension levels. Renal tissue "ouabain" levels were also increased at week 4 of hypertension. However, renal Na+, K(+)-ATPase activity was unchanged. These findings, using two different assays, confirm our 1980 conclusion that SPI is elevated in the plasma of dogs with 1-K, 1W hypertension. The absence of renal Na+, K(+)-ATPase inhibition, despite increased plasma and renal SPI in these animals, may have important implications for the development of this type of hypertension.     

Global Positioning System Derived Performance Measures Are Responsive Indicators of Physical Activity,Disease and the Success of Clinical Treatments in Domestic Dogs

ObjectiveTo assess the use of Global Positioning System receiver (GPS) derived performance measures for differentiating between: 1) different outdoor activities in healthy dogs; 2) healthy dogs and those with osteoarthritis; 3) osteoarthritic dogs before and after treatment with non-steroidal anti-inflammatory analgesia.DesignProspective study.AnimalsTen healthy dogs and seven dogs with osteoarthritis of the elbow joint (OA dogs).ProcedureHealthy dogs were walked on a standard route on-lead, off-lead and subjected to playing activity (chasing a ball) whilst wearing a GPS collar. Each dog was walked for five consecutive days. Dogs with OA were subjected to a single off-lead walk whilst wearing a GPS collar, and then administered oral Carprofen analgesia daily for two weeks. OA dogs were then subjected to the same walk, again wearing a GPS collar.ResultsGPS derived measures of physical performance could differentiate between on-lead activity, off-lead activity and playing activity in healthy dogs, and between healthy dogs and OA dogs. Variation in the performance measures analysed was greater between individual dogs than for individual dogs on different days. Performance measures could differentiate healthy dogs from OA dogs. OA Dogs treated with Carprofen analgesia showed improvements in their physical performance, which returned to values indistinguishable from those of healthy dogs on nearly all the measures assessed.

Conclusions and Clinical Relevance

GPS derived measures of physical performance in dogs are objective, easy to quantify, and can be used to gauge the effects of disease and success of clinical treatments. Specific stimuli can be used to modulate physical performance beyond the self-governed boundaries that dogs will naturally express when allowed to exercise freely without stimulation.     

Down regulation of myocardial β1-adrenoceptor signal transduction system in pacing-induced failure in dogs with aortic stenosis-induced left ventricular hypertrophy

We recently demonstrated that rapid ventricular pacing caused cardiac failure (Failure) in dogs with aortic stenosis-induced left ventricular hypertrophy (Hypertrophy) and isoproterenol caused no significant increases in function, O₂ consumption and intracellular cyclic AMP level in the failing hypertrophied hearts. We tested the hypothesis that alterations in the ₁-adrenoceptor-signal transduction pathway would correlate with the reduced functional and metabolic responses to -adrenergic stimulation during the transition from the compensated hypertrophy to failure. Pressure overload-induced left ventricular hypertrophy was created using aortic valve plication in 10 dogs over a 6-month period. Five months after aortic valve plication, congestive heart failure was induced in 5 dogs by rapid ventricular pacing at 240 bpm for 4 weeks. The density of myocardial ₁-adrenoceptors (fmoles/mg membrane protein; fmoles/g wet tissue) was significantly reduced in the Failure dogs (176 ± 19; 755 ± 136) when compared to those of the Control (344 ± 51; 1,551 ± 203) and the Hypertrophy (298 ± 33; 1,721 ± 162) dogs. The receptor affinities were not significantly different among all groups. There was a small but significant decrease in the percentage of ₁-adrenoceptors of the failing hypertrophied hearts (62 ± 3%) when compared to that of the hypertrophied hearts (77 ± 5%). The basal myocardial adenylyl cyclase activity (rmoles/mg protein/min) was significantly lower in the Failure dogs (45 ± 4) than in the Control (116 ± 14) and Hypertrophy (86 ± 6) dogs. The forskolin (0.1 mM)-stimulated adenylyl cyclase activity was also significantly lower in the Failure dogs (158 ± 17) than in the Control dogs (296 ± 35) and slightly lower than in the Hypertrophy dogs (215 ± 10). There were no significant differences in low Km cyclic AMP-phosphodiesterase activities among all groups. We conclude that down regulation of ₁-adrenoceptors and reduced adenylyl cyclase activities contribute to the decreases in myocardial functions and -adrenergic responses in the failing hypertrophied hearts induced by rapid ventricular pacing.     

Immunological effects of recombinant feline interferon-omega (KT-80) administration in the dog

The immunological effects of recombinant feline interferon-omega (rFeIFN-omega ; KT-80, Toray) were examined on administration to healthy dogs. The activities of whole blood cells, macrophages, and natural killer cells were enhanced. Moreover, the whole blood activity was examined when KT-80 was administered to dogs which had been diagnosed as having natural canine parvovirus (CPV) infection. Only some cases in which the activity increased until 3 hr post-administration survived. These results suggest that rFeIFN-omega (KT-80) treatment enhanced the cellular immunity of normal dogs, and could exert significant therapeutic effects on only natural CPV infected dogs with induced continuous immunoenhancement.     

Defining the Pharmacodynamic Profile and Therapeutic Index of NHS-IL12 Immunocytokine in Dogs with Malignant Melanoma

Background

Interleukin (IL)-12 is a pro-inflammatory cytokine that mediates T-helper type 1 responses and cytotoxic T-cell activation, contributing to its utility as anti-cancer agent. Systemic administration of IL-12 often results in unacceptable toxicity; therefore, strategies to direct delivery of IL-12 to tumors are under investigation. The objective of this study was to assist the preclinical development of NHS-IL12, an immunocytokine consisting of an antibody, which targets necrotic tumor regions, linked to IL-12. Specifically this study sought to evaluate the safety, serum pharmacokinetics, anti-tumor activity, and immune modulation of NHS-IL12 in dogs with naturally occurring cancers.

Methodology/Principal Findings

A rapid dose-escalation study of NHS-IL12 administered subcutaneously to dogs with melanoma was conducted through the Comparative Oncology Trials Consortium (COTC). Eleven dogs were enrolled in four dose-escalation cohorts; thereafter, an additional seven dogs were treated at the defined tolerable dose of 0.8 mg/m². The expanded cohort at this fixed dose (ten dogs in total) was accrued for further pharmacokinetics and pharmacodynamics assessment. NHS-IL12 levels, serum cytokine concentrations, and peripheral blood mononuclear cell characterization (post-treatment) and draining lymph node immune profiling, and tumor biopsies (pre- and post-treatment) were collected. Adverse events included thrombocytopenia, liver enzymopathies, fever, and vasculitis. Correlation between interferon (IFN)-γ induction, adverse events, and NHS-IL12 exposure (maximum concentration and area under the concentration-time curve) were dose-dependent. Serum IL-10 levels and intratumoral CD8⁺ populations increased after treatment. Partial responses, according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria, were observed in two dogs treated with NHS-IL12 0.8 mg/m² and 1.6 mg/m².

Conclusions/Significance

NHS-IL12 was administered safely to dogs with melanoma and both immunologic and clinical activity was observed. This study successfully defined a narrow therapeutic window for systemic delivery of NHS-IL12 via the subcutaneous route. Results will inform the design and implementation of first-in-human clinical trials of NHS-IL12 in cancer patients.     

Subcellular distribution of the phosphate-activated glutaminase activity in the visual analyzer of the brain during postnatal ontogenesis in dogs

The level of general activity of phosphate-activated glutaminase (PAG) on the 1st postnatal day was higher in heavy and light synaptosomes of the exterior geniculate body (EGB) and lower--in the superior colliculus (SC) and visual cortex (field 17); in the subfractions of synaptic mitochondria (E) the general activity of the enzyme was higher in EGB and lower in the visual cortex (field 17) and SC. The level of general activity of the enzyme in the subcellular formations and certain formations of the visual analyzer on the 1st postnatal day was different. This difference varied in the course of postnatal development of the visual system in dogs. The PAG general activity in the subfractions of light (C), heavy (D) synaptosomes, synaptic mitochondria of the membranous enzymes and small synaptosomes sharply enhanced in the visual cortex (field 17) of SC and EGB from the 1st to the 12-14th postnatal days, the subfractions C and D of the visual cortex (field 17) showing the highest degree of the enzyme activity up to the 45th day. SC and EGB subfractions showed a considerable decrease in the enzyme activity of dogs aged 3 months; this peculiarity persisted up to the 6-month age in the above formations, especially in the subfractions B, C, D and E. Dogs aged 1 year exhibited a sharper decrease in the general activity of the enzyme of formations C, D, E in EGB and SC. It was established that with an advance of age the general activity of the enzyme in myelin subfractions (A) mostly increased, especially in the visual cortex (field 17) and EGB of dogs aged 1 year and in SC of dogs aged 6 months.     

Detection of Leishmania infantum DNA in the non-parasitized lung of dogs with visceral leishmaniasis

Background

Despite the very low or absent parasitism in the lungs, the interstitial pneumonitis is a common lesion found in humans and dogs with visceral leishmaniasis. The lung is a neglected organ in the study of dogs and humans with visceral leishmaniasis, but interstitial pneumonitis represents an important lesion characterized by thickening of the alveolar septum due to fibrosis and inflammatory exudate, and its pathogenesis is still uncertain. In this study, the polymerase chain reaction (PCR) was used to detect Leishmania infantum in paraffin-embedded lung biopsies from naturally infected dogs from an endemic area in Minas Gerais State, Brazil; PCR was compared to histological and immunohistochemical techniques for detecting Leishmania.

Results

Eighteen dogs in which leishmaniasis had been diagnosed by serological tests - indirect immunofluorescence assay (IFAT), enzyme-linked immunosorbent assay (ELISA) and complement fixation tests (CFT) - were classified as asymptomatic, oligosymptomatic or symptomatic. Nine of the 18 dogs studied had a positive PCR (50%) but parasites were not detected by histopathological and immunocytochemistry methods.

Conclusions

These data indicate that PCR on DNA extracted from paraffin-embedded tissue is a valuable method for detecting Leishmania infantum parasites in lungs of naturally infected dogs, despite the apparent absence of parasites from standard HE (hematoxylin and eosin) stained slides and of labeled parasites from immunocytochemical preparations.