Het bepalen van het optimale tijdstip voor keizersnede bij de hond in functie van de voorspelde partusdatum

Het optimale tijdstip bepalen voor de keizersnede bij de hond kan een uitdaging betekenen voor de praktijkdierenarts. Er moet rekening gehouden worden met de berekende partusdatum, het al dan niet op gang zijn van de partus en het al dan niet aanwezig zijn van dystocie. Sommige teven hebben een verlengde dracht, bij andere start de partus te vroeg. In beide gevallen is de kans op overleving van de pups zeer laag. Ook wanneer er bij dystocie te lang gewacht wordt om een keizersnede uit te voeren, komt de overleving van de pups in het gedrang. Het is daarom van groot belang de juiste partusdatum bij elke individuele hond te kunnen voorspellen, zeker bij risicopatiënten. De partusdatum kan berekend worden door het begin van de metoestrus te bepalen via vaginale cytologie of door embryonale en foetale structuren te meten via echografie. De meest accurate methode is echter door middel van cyclusopvolging met progesteronmeting.

Immunogenicity and safety of xenogeneic vascular endothelial growth factor receptor-2 DNA vaccination in mice and dogs

Vascular endothelial growth factor receptor-2 (VEGFR-2) is an attractive target in oncology due to its crucial role in angiogenesis. In this study a DNA vaccine coding for human VEGFR-2 was evaluated in healthy mice and dogs, administered by intradermal injection and electroporation. In mice, three doses and vaccination schedules were evaluated. Cellular immune responses were measured by intracellular IFN-gamma staining and a cytotoxicity assay and antibodies by ELISA. Safety was assessed by measuring regulatory T cells and myeloid derived suppressor cells and a wound healing assay. The vaccine was subsequently evaluated in dogs, which were vaccinated three times with 100μg. Cellular immune responses were measured by intracellular IFN-gamma staining and antibodies by a flow cytometric assay. In mice, maximal cellular responses were observed after two vaccinations with 5μg. Humoral responses continued to increase with higher dose and number of vaccinations. No abnormalities in the measured safety parameters were observed. The vaccine was also capable of eliciting a cellular and humoral immune response in dogs. No adverse effects were observed, but tolerability of the electroporation was poor. This study will facilitate the evaluation of the vaccine in tumor bearing animals, ranging from rodent models to dogs with spontaneous tumors.

Anaesthesia, not number of sessions, influences the magnitude and duration of an aHF-rTMS in dogs

BACKGROUND

Currently, the rat has been a useful animal model in brain stimulation research. Nevertheless, extrapolating results from rodent repetitive Transcranial Magnetic Stimulation (rTMS) research to humans contains several hurdles. This suggests the desperate need for a large animal model in translational rTMS research. The dog would be a valid choice, not only due to the fact that humans and dogs share a neurophysiological background, but a similar neuropathological background as well.

HYPOTHESIS

In order to evaluate the feasibility of the canine rTMS animal model, this study aimed to evaluate the neurophysiological response in dogs on a, clinically used, accelerated high frequency (aHF) rTMS protocol. This aHF-rTMS (20 Hz) protocol was performed under anaesthesia or sedation and either 20 sessions or 5 sessions were given to each dog.

METHODS

21 healthy dogs were randomly subjected to one of the four aHF-rTMS protocols (1 sham and 3 active protocols). For each dog, the perfusion indices (PI), of a [99mTc]HMPAO scan at 4 time points, for the left frontal cortex (stimulation target) were calculated for each protocol.

RESULTS

Concerning sham stimulation, the average PI remained at the baseline level. The main result was the presence of a direct transitory increase in rCBF at the stimulation site, both under anaesthesia and sedation. Nevertheless the measured increase in rCBF was higher but shorter duration under sedation. The magnitude of this increase was not influenced by number of sessions. No changes in rCBF were found in remote brain regions.

CONCLUSION

This study shows that, despite the influence of anaesthesia and sedation, comparable and clinically relevant effects on the rCBF can be obtained in dogs. Since less methodological hurdles have to be overcome and comparable results can be obtained, it would be acceptable to put the dog forward as an alternative translational rTMS animal model.

Accurate external localization of the left frontal cortex in dogs by using pointer based frameless neuronavigation

BACKGROUND

In humans, non-stereotactic frameless neuronavigation systems are used as a topographical tool for non-invasive brain stimulation methods such as Transcranial Magnetic Stimulation (TMS). TMS studies in dogs may provide treatment modalities for several neuropsychological disorders in dogs. Nevertheless, an accurate non-invasive localization of a stimulation target has not yet been performed in this species.

HYPOTHESIS

This study was primarily put forward to externally locate the left frontal cortex in 18 healthy dogs by means of a human non-stereotactic neuronavigation system. Secondly, the accuracy of the external localization was assessed.

ANIMALS

A total of 18 healthy dogs, drawn at random from the research colony present at the faculty of Veterinary Medicine (Ghent University), were used.

METHODS

Two sets of coordinates (X, Y, Z and X″, Y″, Z″) were compared on each dog their tomographical dataset.

RESULTS

The non-stereotactic neuronavigation system was able to externally locate the frontal cortex in dogs with accuracy comparable with human studies.

CONCLUSION AND CLINICAL IMPORTANCE

This result indicates that a non-stereotactic neuronavigation system can accurately externally locate the left frontal cortex and paves the way to use guided non-invasive brain stimulation methods as an alternative treatment procedure for neurological and behavioral disorders in dogs. This technique could, in analogy with human guided non-invasive brain stimulation, provide a better treatment outcome for dogs suffering from anxiety disorders when compared to its non-guided alternative.

Estimation of the optimal dosing regimen of escitalopram in dogs: A dose occupancy study with [11C]DASB

Although the favourable characteristics of escitalopram as being the most selective serotonin reuptake inhibitor and having an increased therapeutic efficacy via binding on an additional allosteric binding site of the serotonin transporter, its dosing regimen has not yet been optimized for its use in dogs. This study aimed to estimate the optimal dosing frequency and the required dose for achieving 80% occupancy of the serotonin transporters in the basal ganglia. The dosing frequency was investigated by determining the elimination half-life after a four day oral pre-treatment period with 0.83 mg/kg escitalopram (3 administrations/day) and a subsequent i.v. injection 0.83 mg/kg. Blood samples were taken up to 12 hours after i.v. injection and the concentration of escitalopram in plasma was analysed via LC-MSMS. The dose-occupancy relationship was then determined by performing two PET scans in five adult beagles: a baseline PET scan and a second scan after steady state conditions were achieved following oral treatment with a specific dose of escitalopram ranging from 0.5 to 2.5 mg/kg/day. As the elimination half-life was determined to be 6.7 hours a dosing frequency of three administrations a day was proposed for the second part of the study. Further it was opted for a treatment period of four days, which well exceeded the minimum period to achieve steady state conditions. The optimal dosing regimen to achieve 80% occupancy in the basal ganglia and elicit a therapeutic effect, was calculated to be 1.85 mg/kg/day, divided over three administrations. Under several circumstances, such as insufficient response to other SSRIs, concurrent drug intake or in research studies focused on SERT, the use of escitalopram can be preferred over the use of the already for veterinary use registered fluoxetine, however, in case of long-term treatment with escitalopram, regularly cardiac screening is recommended.

Alfaxalone TIVA bij de chirurgische excisie van een tracheaal adenocarcinoma bij een kat

Een tien jaar oude, vrouwelijke, Europese korthaar werd aangeboden met klachten van progressief verergerende dyspnee, ademen met open muil en inspiratoire en expiratoire stridor. Met behulp van tracheoscopie met bioptname kon de histopathologische diagnose van een intraluminaal tracheaal adenocarcinoma gesteld worden. Computertomografie (CT) toonde aan dat er geen metastasen waren, waarna tijdens dezelfde anesthesie werd overgegaan tot excisie van de tumor. Omwille van de moeilijke hanteerbaarheid van de patiënt was intraveneuze premedicatie niet mogelijk en gebeurde de inductie van de anesthesie aan de hand van een intramusculaire injectie met alfaxalone. De anesthesie werd verder onderhouden met twee verschillende protocollen: initieel werd gebruik gemaakt van een inhalatieanesthesie -protocol, waarbij isofluraan via een laryngeaal masker werd verdampt in 100% zuurstof via een cirkelsysteem, waarna er werd overgeschakeld naar totale intraveneuze anesthesie (TIVA) met alfaxalone tijdens de eigenlijke excisie van de tumor. Door het verwijderen van zeven trachearingen kon de tumor volledig verwijderd worden.

Congenital lobar emphysema in a kitten

A five-month-old ragdoll cat presented with severe respiratory signs, unresponsive to medical therapy. Hyperinflation of the right middle lung lobe was diagnosed with radiography and computed tomography. Lung lobectomy following a median sternotomy led to full recovery. Histopathological analysis revealed lobar emphysema and, based on the animal's age, congenital lobar emphysema was considered the most likely diagnosis.

Vagus Nerve Stimulator Placement in Dogs: Surgical Implantation Technique, Complications, Long-Term Follow-Up, and Practical Considerations

OBJECTIVE

To describe a modified implantation procedure of a vagus nerve stimulation (VNS) device in dogs and to report short- and long-term complications.

STUDY DESIGN

Descriptive, experimental study.

ANIMALS

Healthy, adult Beagle dogs (n = 10).

METHODS

A VNS Therapy(®) System was implanted in the left cervical region of anesthetized dogs. During and within 48 hours after surgery, electrocardiography (ECG) and impedance testing of the system were performed. Dogs were monitored daily and the impedance of the system was determined regularly until VNS devices were surgically removed 3 years after implantation.

RESULTS

The implantation procedure was successful in all dogs without intraoperative complications. ECG monitoring and impedance tests were within normal limits during and within 48 hours after surgery. Postoperative seroma formation was common (70%). One dog developed an irreversible Horner's syndrome leading to removal of the device 5 months after implantation. Another dog developed trauma-induced damage of the lead requiring surgical revision. The device could be safely removed in all dogs; however, electrodes were left in place to avoid nerve damage. At removal, the anchor tether was dislodged in 40% of dogs and the lead was twisted in 50% of dogs.

CONCLUSION

Implantation of a VNS Therapy(®) System is safe and feasible in dogs; however, seroma formation, twisting of the lead, and dislodgement of the anchor tether were common. Practical improvements in the technique include stable device placement, use of a compression bandage, and exercise restriction. Regular evaluation of lead impedance is important, as altered values can indicate serious complications.

Behandeling van een chronische huidwonde bij een hond via negatieve druktherapie

Een vier jaar en acht maanden oude whippet werd aangeboden met een chronische huidwonde ter hoogte van het mediale aspect van de rechterelleboog. Wegens de chroniciteit van de wonde werd het wondbed eerst zorgvuldig gedebrideerd en nadien behandeld met negatieve druktherapie. Deze relatief nieuwe techniek in de diergeneeskunde biedt allerlei voordelen die het genezingsproces van een chronische wonde ten goede komen. In de huidige casus leidde de negatieve druktherapie in eerste instantie tot de snelle ontwikkeling van een mooi granulatiebed. Om een optimaal eindresultaat te bekomen werd daaropvolgend gebruik gemaakt van een autologe huidtransplantatie (“full-thickness mesh graft”), die eveneens onder negatieve druktherapie werd geplaatst. Dit zorgde, ondanks de lastige lokalisatie van de wonde, voor een snelle aanhechting en optimale overleving van de huidgreffe. Na amper vier weken was de wonde nagenoeg volledig geheeld, terwijl ze eerder, ondanks allerlei behandelingen, gedurende meer dan twee maanden geen genezing vertoonde.

No evidence that medicinal honey reduces bacterial skin colonisation at a peripheral catheter insertion site in dogs

OBJECTIVES

To determine whether topical exit-site application of medicinal honey at the catheter insertion place reduces bacterial skin colonisation.

MEASUREMENTS AND RESULTS

Dogs were selected at random and divided into the honey or the control group. When the catheter was removed, an area of approximately 3×3 cm of the skin at the insertion site was sampled with a sterile cotton swab. The catheter stayed in place for a median of 84 hours. Out of 46 patients, 6 patients in the honey group and 5 out of 54 patients in the control group had a positive skin culture at the time of catheter removal (P=0·547). Infection was clinically suspected in 1 of those 11 dogs; catheter-associated complications were observed in 8 additional dogs that did not have a positive skin culture.

CLINICAL SIGNIFICANCE

Few catheter-associated complications were observed. Extra attention to hygiene by working with a standardised catheter placement and handling protocol might have resulted in this low incidence. In this study topical application of a medicinal honey did not reduce bacterial skin colonisation at the insertion site of peripheral catheters in dogs.

Immunological and angiogenic markers during metronomic temozolomide and cyclophosphamide in canine cancer patients

Metronomic chemotherapy stimulates the immune response via depletion of regulatory T cells (Tregs) and suppresses angiogenesis by modulating the secretion of thrombospondin-1 (TSP-1) and vascular endothelial growth factor (VEGF). In this study, blood was collected from 10 healthy dogs and from 30 canine cancer patients before and 2 and 4 weeks after treatment with metronomic temozolomide (6.6 mg m^-2 ), cyclophosphamide (12.5 mg m^-2 ) or cyclophosphamide and temozolomide. The percentage of circulating CD25⁺ Foxp3⁺ CD4⁺ Tregs and the plasma levels of TSP-1 and VEGF were measured. There was a significant difference in the percentage of Tregs between cancer patients and healthy dogs. A significant decrease in Tregs was noted in patients treated with metronomic cyclophosphamide and the combination. Treatment with temozolomide had no effect on the percentage of Tregs. TSP-1 and VEGF levels were, respectively, significantly lower and higher in cancer patients than in healthy dogs, but they were not influenced by any of the studied metronomic treatment regimens.

Cosmetische rostrale neusreconstructie na plaveiselcelcarcinoomresectie bij twee honden

Twee mannelijke golden retrievers van ongeveer tien jaar oud werden aangeboden met een zichtbare massa in de neus, niesden en vertoonden epistaxis. Uit histologisch onderzoek na bioptname bleek dat het bij beide honden om een plaveiselcelcarcinoom ging. Bij verdere stagering waren er geen aanwijzingen voor metastasen. Chirurgische wegname van de tumor door middel van een planectomie of nosectomie werd voorgesteld. Omdat de klassieke excisie van de neusspiegel voor deze eigenaars cosmetisch onaanvaardbaar was, werd bij beide honden gekozen voor een rostrale neusreconstructie. Bij de eerste hond bevond de tumor zich aan de oppervlakte, waardoor resectie van het kraakbenig deel van de neus voldoende was en een planectomie werd uitgevoerd. Bij de tweede hond daarentegen was er tevens botaantasting, waardoor niet alleen de neus, maar ook het os incisiva werd verwijderd (nosectomie). Bij beide honden werd een remissie van de tumor verkregen na een follow-up van respectievelijk 35 en 29 maanden, met tegelijkertijd een uitstekend cosmetisch resultaat.

In Vivo Evaluation of Blood Based and Reference Tissue Based PET Quantifications of [11C]DASB in the Canine Brain

This first-in-dog study evaluates the use of the PET-radioligand [¹¹C]DASB to image the density and availability of the serotonin transporter (SERT) in the canine brain. Imaging the serotonergic system could improve diagnosis and therapy of multiple canine behavioural disorders. Furthermore, as many similarities are reported between several human neuropsychiatric conditions and naturally occurring canine behavioural disorders, making this tracer available for use in dogs also provide researchers an interesting non-primate animal model to investigate human disorders. Five adult beagles underwent a 90 minutes dynamic PET scan and arterial whole blood was sampled throughout the scan. For each ROI, the distribution volume (V_T), obtained via the one- and two- tissue compartment model (1-TC, 2-TC) and the Logan Plot, was calculated and the goodness-of-fit was evaluated by the Akaike Information Criterion (AIC). For the preferred compartmental model BP_ND values were estimated and compared with those derived by four reference tissue models: 4-parameter RTM, SRTM2, MRTM2 and the Logan reference tissue model. The 2-TC model indicated in 61% of the ROIs a better fit compared to the 1-TC model. The Logan plot produced almost identical V_T values and can be used as an alternative. Compared with the 2-TC model, all investigated reference tissue models showed high correlations but small underestimations of the BP_ND-parameter. The highest correlation was achieved with the Logan reference tissue model (Y = 0.9266 x + 0.0257; R² = 0.9722). Therefore, this model can be put forward as a non-invasive standard model for future PET-experiments with [¹¹C]DASB in dogs.

In vivo quantification of the [(11)C]DASB binding in the normal canine brain using positron emission tomography

Background

[¹¹C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile ([¹¹C]DASB) is currently the mostly used radiotracer for positron emission tomography (PET) quantitative studies of the serotonin transporter (SERT) in the human brain but has never been validated in dogs. The first objective was therefore to evaluate normal [¹¹C]DASB distribution in different brain regions of healthy dogs using PET. The second objective was to provide less invasive and more convenient alternative methods to the arterial sampling-based kinetic analysis.

Results

A dynamic acquisition of the brain was performed during 90 min. The PET images were coregistered with the magnetic resonance images taken prior to the study in order to manually drawn 20 regions of interest (ROIs). The highest radioactivity concentration of [¹¹C]DASB was observed in the hypothalamus, raphe nuclei and thalamus and lowest levels in the parietal cortex, occipital cortex and cerebellum.

The regional radioactivity in those 20 ROIs was quantified using the multilinear reference tissue model 2 (MRTM2) and a semi-quantitative method. The values showed least variability between 40 and 60 min and this time interval was set as the optimal time interval for [¹¹C]DASB quantification in the canine brain. The correlation (R²) between the MRTM2 and the semi-quantitative method using the data between 40 and 60 min was 99.3 % (two-tailed p-value < 0.01).

Conclusions

The reference tissue models and semi-quantitative method provide a more convenient alternative to invasive arterial sampling models in the evaluation of the SERT of the normal canine brain. The optimal time interval for static scanning is set at 40 to 60 min after tracer injection.

Stimulation of in vivo dopamine transmission and intravenous self-administration in rats and mice by JWH-018, a Spice cannabinoid

The synthetic cannabinoid 1-pentyl-3-(1-naphthoyl)-indole (JWH-018) has been detected in about 140 samples of a smokable herbal mixture termed "Spice". JWH-018 is a CB1 and CB2 agonist with a higher affinity than Δ9-THC. In order to investigate the neurobiological substrates of JWH-018 actions, we studied by microdialysis in freely moving rats the effect of JWH-018 on extracellular dopamine (DA) levels in the nucleus accumbens (NAc) shell and core and in the medial prefrontal cortex (mPFC). JWH-018, at the dose of 0.25 mg/kg i.p., increased DA release in the NAc shell but not in the NAc core and mPFC. Lower (0.125 mg/kg) and higher doses (0.50 mg/kg) were ineffective. These effects were blocked by CB1 receptor antagonists (SR-141716A and AM 251) and were absent in mice lacking the CB1 receptor. Ex vivo whole cell patch clamp recordings from rat ventral tegmental area (VTA) DA neurons showed that JWH-018 decreases GABAA-mediated post-synaptic currents in a dose-dependent fashion suggesting that the stimulation of DA release observed in vivo might result from disinhibition of DA neurons. In addition, on the "tetrad" paradigm for screening cannabinoid-like effects (i.e., hypothermia, analgesia, catalepsy, hypomotility), JWH-018, at doses of 1 and 3 mg/kg i.p., produced CB1 receptor-dependent behavioural effects in rats. Finally, under appropriate experimental conditions, rats (20 μg/kg/inf i.v., FR3; nose-poking) and mice (30 μg/kg/inf i.v., FR1; lever-pressing) self-administer intravenously JWH-018. In conclusion, JWH-018 shares with the active ingredient of Marijuana, Δ9-THC, CB1-dependent reinforcing and DA stimulant actions.

Cell-Penetrating Peptides Selectively Cross the Blood-Brain Barrier In Vivo

Cell-penetrating peptides (CPPs) are a group of peptides, which have the ability to cross cell membrane bilayers. CPPs themselves can exert biological activity and can be formed endogenously. Fragmentary studies demonstrate their ability to enhance transport of different cargoes across the blood-brain barrier (BBB). However, comparative, quantitative data on the BBB permeability of different CPPs are currently lacking. Therefore, the in vivo BBB transport characteristics of five chemically diverse CPPs, i.e. pVEC, SynB3, Tat 47-57, transportan 10 (TP10) and TP10-2, were determined. The results of the multiple time regression (MTR) analysis revealed that CPPs show divergent BBB influx properties: Tat 47-57, SynB3, and especially pVEC showed very high unidirectional influx rates of 4.73 μl/(g × min), 5.63 μl/(g × min) and 6.02 μl/(g × min), respectively, while the transportan analogs showed a negligible to low brain influx. Using capillary depletion, it was found that 80% of the influxed peptides effectively reached the brain parenchyma. Except for pVEC, all peptides showed a significant efflux out of the brain. Co-injection of pVEC with radioiodinated bovine serum albumin (BSA) did not enhance the brain influx of radiodionated BSA, indicating that pVEC does not itself significantly alter the BBB properties. A saturable mechanism could not be demonstrated by co-injecting an excess dose of non-radiolabeled CPP. No significant regional differences in brain influx were observed, with the exception for pVEC, for which the regional variations were only marginal. The observed BBB influx transport properties cannot be correlated with their cell-penetrating ability, and therefore, good CPP properties do not imply efficient brain influx.

Epinephrine-enhanced computed tomographic arthrography of the canine shoulder

The aim of this study was to investigate the effect of epinephrine-enhanced computed tomographic arthrography (CTA) on the image sharpness of the lateral and medial glenohumeral ligaments (LGHL and MGHL, respectively), biceps tendon (BT) and joint cartilage (JC) in the canine shoulder. The shoulders of eight normal dogs were examined using a 4-slice helical CT scanner. The right shoulders were injected with Iohexol and the left shoulders with a mixture of Iohexol and epinephrine. CTA images were obtained after 1, 3, 5, 9, 13, 20 and 30 min and the image sharpness of the intra-articular structures in both shoulders was graded for visibility. The attenuation values were measured to examine the persistence of contrast appearance. Admixture of epinephrine and Iohexol significantly improved the image sharpness of the LGHL and the BT, especially on delayed CTA images. The use of epinephrine did not negatively affect post-CTA recovery.

Low-Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs

BACKGROUND

Syringomyelia (SM) is defined as the presence of fluid-containing cavities within the parenchyma of the spinal cord. Sagittal magnetic resonance (MR) images have been described as the preferred technique for visualizing SM in dogs and humans.

OBJECTIVE

To investigate whether computed tomography (CT) can be used to diagnose SM.

ANIMALS

Thirty-two client-owned dogs referred for investigation of the cervical spine on magnetic resonance imaging (MRI) and CT.

METHODS

Two reviewers retrospectively analyzed sagittal and transverse T1-weighted spin echo (T1WSE) MR images and CT images from each dog for the presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was measured. The results were analyzed statistically.

RESULTS

For the presence of SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and almost perfect agreement for CT (94%, κ = 0.87). There was a moderate intramodality agreement for both observers (observer 1 81%, κ = 0.59; observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the best on the midsagittal T1WSE images (95% repeatability coefficient <0.52 mm) and the reproducibility was the best on midsagittal images in both modalities (95% limits of agreement -0.55-0.45; P = 0.002).

CONCLUSION AND CLINICAL IMPORTANCE

Both techniques can be used to detect SM. Midsagittal MR and CT images are best used for measuring SW. Computed tomography can be used as a diagnostic tool for SM when MRI is not available, but CT cannot replace MRI as the standard screening technique for the detection of SM in Cavalier King Charles Spaniel for breeding purposes.

Clinical parameters as predictors of bacterial isolation in the uterine content of dogs suspected of pyometra

In this study, female canines referred with clinical signs consistent with pyometra were prospectively evaluated. Signalment, clinical signs, laboratory findings and surgical findings were compared between dogs with and without bacterial isolation based on aerobic techniques. Patients with positive bacterial isolation were placed in the pyometra group, whereas patients with negative bacterial isolation were grouped as mucometra. A total of 140 dogs (118 with pyometra and 22 with mucometra) met the inclusion criteria. Prereferral antibiotic administration was associated with a prolonged duration of clinical signs in the patients of the pyometra group (12 ± 2 days versus 7 ± 1 days; P=0.006). In the pyometra patients, clinical signs, like pyrexia, anorexia and discomfort on abdominal palpation, were observed more commonly than in the mucometra group. The total leukocyte count was the only parameter that differed significantly between the two groups (P=0.01). Although no difference in color and consistency of the uterine fluid was noted, the uteri of the pyometra group were heavier (851.80 ± 800.30 g compared to 263.50 ± 297.10 g). E. coli was the most commonly isolated bacterium (92/123).

Relationship between age at gonadectomy and health problems in kittens adopted from shelters

Prepubertal gonadectomy (PPG) is promoted as a way of managing overpopulation in cats, but concerns about PPG and potential health issues still exist. The objective of the present study was to evaluate short-term and long-term health problems in cats subjected to PPG in comparison to gonadectomy at traditional age (TAG). In a prospective clinical trial, 800 shelter kittens aged between approximately 8 weeks and 12 weeks were recruited before adoption and randomly assigned to either the PPG group (gonadectomy performed immediately) or the TAG group (gonadectomy delayed until six months to eight months of age). Short-term health issues included mortality between when kittens arrived at the clinic and up to seven days after they returned to the shelter, as well as the occurrence of various other health issues arising in the first month following adoption. Kittens were followed-up until 24 months of age specifically for feline lower urinary tract disease, urethral obstruction (male cats), lameness, fractures and hypersensitivity disorders with dermatological presentation. In the short term, there were no significant differences between health problems in PPG and TAG kittens. Similarly, no significant differences were observed between treatment groups in terms of the type or number of health issues in the long term. In conclusion, there are no health-related contraindications to advocating PPG strategies in shelter cats. Ideally, PPG should be performed at the shelter facility itself as long as excellent infectious disease control and postoperative clinical observation before adoption are guaranteed.

Blood-brain transfer and antinociception of linear and cyclic N-methyl-guanidine and thiourea-enkephalins

Enkephalins are active in regulation of nociception in the body and are key in development of new synthetic peptide analogs that target centrally located opioid receptors. In this study, we investigated the in vivo blood-brain barrier (BBB) penetration behavior and antinociceptive activity of two cyclic enkephalin analogs with a thiourea (CycS) or a N-methyl-guanidine bridge (CycNMe), and their linear counterparts (LinS and LinNMe) in mice, as well as their in vitro metabolic stability. (125)I-LinS had the highest blood-brain clearance (K1=3.46μL/gmin), followed by (125)I-LinNMe, (125)I-CycNMe, and (125)I-CycS (K1=1.64, 0.31, and 0.11μL/gmin, respectively). Also, these peptides had a high metabolic stability (t1/2>1h) in mouse serum and brain homogenate, and half-inhibition constant (Ki) values in the nanomolar range with predominantly μ-opioid receptor selectivity. The positively charged NMe-enkephalins showed a higher antinociceptive activity (LinNMe: 298% and CycNMe: 205%), expressed as molar-dose normalized area under the curve (AUC) relative to morphine, than the neutral S-enkephalins (CycS: 122% and LinS: 130%).