Base Of Tail Research Articles

Diphencyprone reduces the CD8+ lymphocytes and IL-4 and enhences IgG2a/IgG1 ratio in pathogenicity of acute leishmania major infection in BALB/c mice

BackgroundThe exact role of different immune cells and cytokines in control or promotion of intracellular growth of leishmania has still remained a controversial topic. The aim of the present study was to study effects of cellular changes and relevant cytokines in cell mediated immunity by diphencyprone (DCP) in pathogenicity of acute L.major infection in BALB/c mice. Methods45 healthy female BALB/c mice were injected with L. major promastigotes under the base of tail. The mice were randomly divided to three groups of 15 mice: (1) control group without any treatment. (2) acetone group: Acetone was applied topically on the cutaneous lesions weekly and (3) DCP group: DCP was applied topically on the cutaneous lesions with increasing concentrations to induce local allergy. The mice were followed by the end of eighth week, and then macroscopic changes, histopathology, immunology studies, and organ parasite burden were determined. ResultsIn DCP group, in comparison to other groups the ulcer size and parasite burden in ulcer site and spleen increased, significantly. There was a deep lymphohistiocytic infiltration in the ulcer site. Total IgG, IgG1, and IgG2a levels as well as IgG2a/IgG1 ratio and intracellular IFN-gamma in CD8+ lymphocytes were significantly higher. IL4 and T CD8+ lymphocytes were significantly lower in DCP group. The IgG2a/IgG1 ratio was more than 1 in all groups. ConclusionOur findings demonstrated that DCP reduced the CD8+ lymphocytes and IL-4 production. In spite of increased IgG2a/IgG1 ratio, the parasite burden and inflammation severity increased in infected mice. The results can show the pivotal role of CD8+ lymphocytes in conjunction with Th1 lymphocytes in the control of acute leishmania infection in mice.

Genomic Prediction and Genome-Wide Association Studies for Productivity, Conformation and Heat Tolerance Traits in Tropical Smallholder Dairy Cows.

Genomic selection (GS) and genome-wide association studies (GWAS) have not been investigated in Vietnamese dairy cattle, even for basic milk production traits, largely due to the scarcity of individual phenotype recording in smallholder dairy farms (SDFs). This study aimed to estimate heritability (h2) and test the applicability of GS and GWAS for milk production, body conformation and novel heat tolerance traits using single test day phenotypic data. Thirty-two SDFs located in either the north (a lowland vs. a highland) or the south (a lowland vs. a highland) of Vietnam were each visited for an afternoon and the next morning to collect phenotype data of all lactating cows (n = 345). Tail hair from each cow was sampled for subsequent genotyping with a 50K SNP chip at that same visit. Milk production traits (single-test day) were milk yield (MILK, kg/cow/day), energy corrected milk yield adjusted for body weight (ECMbw, kg/100 kg BW/day), fat (mFA, %), protein (mPR, %) and dry matter (mDM, %). Conformation traits were body weight (BW, kg) and body condition score (BCS, 1 = thin to 5 = obese). Heat tolerance traits were panting score (PS, 0 = normal to 4.5 = extremely heat-stressed) and infrared temperatures (IRTs, °C) at 11 areas on the external body surface of the cow (inner vulval lip, outer vulval surface, inner tail base surface, ocular area, muzzle, armpit area, paralumbar fossa area, fore udder, rear udder, forehoof and hind hoof), assessed by an Infrared Camera. Univariate linear mixed models and a 10-fold cross-validation approach were applied for GS. Univariate single SNP mixed linear models were applied for the GWAS. Estimated h2 (using the genotype information to build relationships among animals) were moderate (0.20-0.37) for ECMbw, mFA, mPR, mRE, BW, BCS and IRT at rear udder; low (0.08-0.19) for PS and other IRTs; and very low (≤ 0.07) for MILK, ECM and mDM. Accuracy of genomic estimated breeding values (GEBVs) was low (≤ 0.12) for MILK, ECM, mDM and IRT at hind hoof; and moderate to high (0.32-0.46) for all other traits. The most significant regions on chromosomes (BTA) associated with milk production traits were 0.47-1.18 Mb on BTA14. Moderate to high h2 and moderate accuracies of GEBVs for mFA, mPR, ECMbw, BCS, BW, PS and IRTs at rear udder and outer vulval surface suggested that GS using single test day phenotypic data could be applied for these traits. However, a greater sample size is required to decrease the bias of GEBVs by GS and increase the power of detecting significant quantitative trait loci (QTLs) by GWAS.

Magnetic particle imaging enables non-radioactive quantitative sentinel lymph node identification: feasibility proof in murine models

Abstract Background Sentinel lymph node biopsy (SLNB) is an important cancer diagnostic-staging procedure. Conventional SLNB procedures with 99mTc radiotracers and scintigraphy are constrained by tracer half-life and in some cases insufficient image resolution. Here we explore an alternative magnetic (non-radioactive) image guided SLNB procedure. Purpose To demonstrate that magnetic particle imaging (MPI) lymphography can sensitively, specifically, and quantitatively identify and map SLNs in murine models in multiple regional lymphatic basins. Materials and Methods Iron oxide nanoparticles were administered intradermally to healthy C57BL/6 mice (male, 12-week-old, n = 5). The nanoparticles (0.675 mg Fe/kg) were injected into the tongue, forepaw, base of tail, or hind footpad, then detected by 3D MPI at multiple timepoints between 1 hour and 4-6 days. In this mouse model, the SLN is represented by the first lymph node draining from the injection site. SLNs were extracted to verify the MPI signal ex vivo and processed using Perl’s Prussian iron staining. Paired t-test was conducted to compare MPI signal from SLNs in vivo vs. ex vivo and considered significant if p < .05. Results MPI lymphography identified SLNs in multiple lymphatic pathways, including the cervical SLN draining the tongue, axillary SLN draining the forepaw, inguinal SLN draining the tail, and popliteal SLN draining the footpad. MPI signal in LNs was present after 1 hour and stable for the duration of the study (4-6 days). Perl’s Prussian iron staining was identified in the subcapsular space of excised SLNs. Conclusion Our data supports the use of MPI lymphography to specifically detect SLN(s) using a magnetic tracer for a minimum of 4-6 days, thereby providing information required to plan the SLN approach in cancer surgery. As clinical-scale MPI is developed, translation will benefit from a history of using iron-oxide nanoparticles in human imaging and recent regulatory-approvals for use in SLNB.

Automated analysis of a novel object recognition test in mice using image processing and machine learning

The novel object recognition test (NORT) is one of the most commonly employed behavioral tests in experimental animals designed to evaluate an animal's interest in and recognition of novelty. However, manual procedures, which rely on researchers’ observations, prevent high throughput analysis. In this study, we developed an automated analysis method for NORT utilizing machine learning-assisted exploratory behavior detection. We recorded the exploratory behavior of the mice using a video camera. The coordinates of the mouse nose and tail base in recorded video files were detected using a pre-trained machine learning model, DeepLabCut. Each video was then segmented into frame images, which were categorized into "exploratory,” or "non-exploratory" frames based on manual observation. Mouse feature vectors were calculated as vectors from the nose to the vertices of the object and were utilized for SVM training. The trained SVM effectively detected exploratory behaviors, showing a strong correlation with human observer assessments. Upon application to NORT, the duration of mouse exploratory behavior towards objects predicted by the SVM exhibited a significant correlation with the assessments made by human observers. The novelty discrimination index derived from the SVM predictions also aligned well with that from human observations.

Does Catheter Insertion Site Matter? Contamination of Peripheral Intravenous Catheters during Dental Scaling in Dogs.

During dental scaling in dogs under general anaesthesia, contamination of the peripheral intravenous catheter (PIVC) is unavoidable due to splatter and the generated aerosol. Bacterial contamination was compared between two commonly used PIVC placement sites. Thirty-nine client-owned dogs with a minimum length from their nose to their tail base of 50 cm were randomly assigned to receive a PIVC in either their cephalic or saphenous vein. Irrespective of the PIVC placement site, brain heart infusion agar dishes were placed in the cephalic and saphenous vein areas. Their lids were closed 0, 5, and 10 min into the procedure. Contamination was measured by counting the colony-forming units after incubation on different substrates. The data were analysed with descriptive statistics, ANOVA, and ANCOVA (p < 0.05). The cephalic vein area showed a significantly higher bacterial load than the saphenous vein area (p ≈ 0.0) regardless of the length of the dog. Furthermore, the dorsal PIVC injection ports were sampled before and after scaling, and the colonies isolated were counted and subjected to MALDI-TOF-MS for identification. The bacteria mainly belonged to the genera Staphylococcus, Neisseria, and Bacillus. Our results suggest that for dental scaling in dogs, the PIVC should be placed in the pelvic limb whenever possible to reduce the potential risk of contamination.

Asymmetry of Microcirculation Parameters in Rats against the Background Conditions of LPS Administration.

The effect of intraperitoneal injection of LPS (pyrogenal, 100 μg/kg) on the asymmetry of the right-left hemodynamic balance of microcirculation (MCR) was studied in 10 male Wistar rats. Synchronous measurements of the MCR parameters of the outer surface of the symmetrical areas of the tail base were carried out by laser Doppler flowmetry. The coefficients of asymmetry of the regression relationships between changes in perfusion of each of the observation sides and the initial perfusion values of both the eponymous and opposite observation sides, as well as the mean values and coefficients of perfusion variation of the studied areas, were analyzed. Injection of pyrogenal changed parameters of the asymmetry of the right-left hemodynamic balance of MCR in comparison with the initial values. One hour after the injection of pyrogenal, the contribution of the left MCR bed to the right-left hemodynamic balance increased, and the right one decreased. At the same time, the value of the perfusion variation coefficient decreased on the left and increased on the right. The shift of the hemodynamic balance towards the left MCR bed led to significant increase in blood supply to the left MCR pool after pyrogenal injection. The results of the studies indicate a stress type of reaction of the animal body to the injected drug.

Abstract Mo132: Pouring Salt in the Wound: Sex-specific Cardiometabolic Responses to Increased Dietary Fat, Sugar, and Salt.

Introduction: The general population is becoming more obese, and diabetes rates continue to rise, with overnutrition and consumption of processed foods likely contributing factors. Many people consume diets high in fat, sugar, and salt; however, this triad of factors is rarely examined in unison in studies. In addition, studies that examined diets high in fat and sugar in the context of heart failure with preserved ejection fraction and cardiometabolic outcomes have often performed short dietary interventions, with many studies performed in only male mice, and dietary salt content is often not considered or manipulated. Study Goal: This study aimed to assess the long-term impact of high-fat, high-sucrose diets with differing levels of salt (NaCl) on systemic and cardiovascular physiology in male and female mice. Methods and Results: 12-week-old C57BL/6J male and female mice ( n = 4/group) were fed one of the following diets for 25 weeks: normal chow (NC), low-fat diet (LFD; 10 kcal%), high-fat high sucrose (HFHS; 60 kcal%) with 0.33% NaCl, HFHS with 1% NaCl (HFHS1%), and HFHS with 8% NaCl (HFHS8%). Mice were subjected to basal tail blood metabolite assessment and weighed weekly. In week 24, mice were subjected to glucose tolerance testing, dual-energy X-ray absorptiometry followed by postmortem gravimetric, blood metabolite, histological, and biochemical analyses at 25 weeks. We found that irrespective of sex, body weight was significantly greater in mice receiving HFHS ( p &lt;0.001) and HFHS1% ( p &lt;0.001) versus the other diets. By 25 weeks, male mice were significantly larger than female mice with all diets except HFHS1% ( p &lt;0.05), which correlated with increased percent body fat ( p &lt;0.01), impaired glucose tolerance ( p &lt;0.05) and increased ketone levels ( p &lt;0.05) in female mice subjected to HFHS1% versus males on the same diet. There was also increased heart weight and atrial weights in female mice subjected to HFHS and HFHS1% versus the other females, which was not observed in male mice. Conclusions: Although previous short-term dietary studies have shown that males have altered cardiometabolic responses more than females, our findings together show that long-term dietary interventions with HFHS diets with salt may adversely impact female systemic and cardiovascular physiology.

A non-invasive approach to measuring body dimensions of wildlife with camera traps: A felid field trial.

Dimensions of body size are an important measurement in animal ecology, although they can be difficult to obtain due to the effort and cost associated with the invasive nature of these measurements. We avoid these limitations by using camera trap images to derive dimensions of animal size. To obtain measurements of object dimensions using this method, the size of the object in pixels, the focal length of the camera, and the distance to that object must be known. We describe a novel approach of obtaining the distance to the object through the creation of a portable distance marker, which, when photographed, creates a "reference image" to determine the position of the animal within an image. This method allows for the retrospective analysis of existing datasets and eliminates the need for permanent in-field distance markers. We tested the accuracy of this methodology under controlled conditions with objects of known size resembling Felis catus, our study species, validating the legitimacy of our method of size estimation. We then apply our method to measure feral cat body size using images collected in Tasmania, Australia. The precision of our methodology was evaluated by comparing size estimates across individual cats, revealing consistent and reliable results. The average height (front paw to shoulder) of the feral cats sampled was 25.25 cm (CI = 24.4, 26.1) and the average length (base of tail to nose) was 47.48 cm (CI = 46.0, 48.9), suggesting wild feral cats in our study area are no larger than their domestic counterparts. Given the success of its application within our study, we call for further trails with this method across a variety of species.

Human Olivocochlear Effects: A Statistical Detection Approach Applied to the Cochlear Microphonic Evoked by Swept Tones.

The human medial olivocochlear (MOC) reflex was assessed by observing the effects of contralateral acoustic stimulation (CAS) on the cochlear microphonic (CM) across a range of probe frequencies. A frequency-swept probe tone (125-4757Hz, 90dB SPL) was presented in two directions (up sweep and down sweep) to normal-hearing young adults. This study assessed MOC effects on the CM in individual participants using a statistical approach that calculated minimum detectable changes in magnitude and phase based on CM signal-to-noise ratio (SNR). Significant increases in CM magnitude, typically 1-2dB in size, were observed for most participants from 354 to 1414Hz, where the size and consistency of these effects depended on participant, probe frequency, sweep direction, and SNR. CAS-related phase lags were also observed, consistent with CM-based MOC studies in laboratory animals. Observed effects on CM magnitude and phase were in the opposite directions of reported effects on otoacoustic emissions (OAEs). OAEs are sensitive to changes in the motility of outer hair cells located near the peak region of the traveling wave, while the effects of CAS on the CM likely originate from MOC-related changes in the conductance of outer hair cells located in the basal tail of the traveling wave. Thus, MOC effects on the CM are complementary to those observed for OAEs.

Fluctuations in equine cutaneous pH and transepidermal water loss with time of day and ambient conditions

Cutaneous pH and transepidermal water loss (TEWL) are commonly utilized measures in dermatological research as they provide information concerning barrier function. The importance of dermal health has become more evident in recent years. Accordingly, the aim of this work was to identify natural fluctuations in the biophysical parameters of healthy equine skin. Cutaneous pH and TEWL was collected on nine mares at 6:00 AM, 12:00 PM, and 6:00 PM daily for five days on the nose, withers, girth area, mid-back, and base of tail. Ambient temperature and humidity were measured at each collection. Statistical analysis was completed using SAS On Demand. Tests included repeated measures, ANOVA, and regression analysis. Mean cutaneous pH significantly differed by day (P = 0.0052) and time (P = 0.0073) but was unaffected by anatomical location (P = 0.2841). Interestingly, cutaneous pH had a significant interaction of day and location (P = 0.0004). Mean TEWL measures significantly differed by day (P < 0.0001), time (P < 0.0001), and anatomical location (P = 0.0231). Interaction of day and time had a significant effect on TEWL (P < 0.0001) and also resulted in a three-way interaction of day, time, and location (P = 0.0167). There were no significant associations of pH with temperature and humidity. All measures of TEWL across all locations were significantly correlated with temperature and humidity (P < 0.0001). Cutaneous pH and TEWL measures are affected by environmental conditions which should be considered in future models and work using dermal characteristics of horses.

The potential utility of (2S,4R)-4-[18F] fluoroglutamine as a novel metabolic imaging marker for inflammation explored by rat models of arthritis and paw edema.

(2S,4R)-4-[18F]fluoroglutamine ([18F]FGln) is a promising metabolic imaging marker in cancer. Based on the fact that major inflammatory cells are heavily dependent on glutamine metabolism like cancer cells, we explored the potential utility of [18F]FGln as a metabolic imaging marker for inflammation in two rat models: carrageenan-induced paw edema (CIPE) and collagen-induced arthritis (CIA). The CIPE model (n = 4) was generated by injecting 200 μL of 3% carrageenan solution into the left hind paw three hours before the PET. The CIA model (n = 4) was generated by injecting 200 μg of collagen emulsion subcutaneously at the tail base 3-4 weeks before the PET. A qualitative scoring system was used to assess the severity of paw inflammation. After a CT scan, 15.7 ± 4.9 MBq of [18F]FGln was injected via the tail vein, followed by a dynamic micro-PET scan for 90 minutes under anesthesia with isoflurane. The standard uptake value of [18F]FGln was measured by placing a volume of interest in each paw. The non-injected right hind paws of the CIPE model rats served as controls for both models. The paws with CIA were pathologically examined after PET. In CIPE models, uptake in the injected paw was higher compared to the non-injected paw by 52-83%. In CIA models, uptake in the paws with severe inflammation was higher than the averaged controls by 54-173%, while that with mild and no inflammation was slightly higher (33%) and lower (-7%), respectively. Combined overall, the [18F]FGln uptake in CIA showed a significant positive correlation with inflammation severity (r = 0.88, P = 0.009). The pathological findings confirmed profound inflammation in CIA. [18F]FGln uptake was increased in both acute and chronic inflammation, and the uptake level was significantly correlated with the severity, suggesting its potential utility as a novel metabolic imaging marker for inflammation.

Placentome size in Bos taurus x Bos indicus crosses in the mexican tropics differs from the source breeds

The objective of the present study is to verify the size of placentomes, through ultrasonography, at different gestational ages in Bos indicus x Bos taurus crosses located in the tropics.Placentome size in cows can vary in response to many factors, including crossbreeding. Placentome measurents were taken by averaging the length and width of the placentome.We measured placentome size at different gestational ages in Bos taurus x Bos indicus cows raised in the tropics. Uteruses were collected immediately after slaughter from 102 cows with gestations ≥ 30 days and processed in the abattoir. All cows were Swiss Brown x Zebu phenotypes. Fetus gestational age was estimated by measuring from the crown to the tail base. Five placentomes were randomly chosen from each uterus (n= 510), and diameter (cm) measured for each. Gestational age was classified into nine categories (days): a) ≤45, b) &gt;45 ≤60, c) &gt;60 ≤90, d) &gt;90 ≤120, e) &gt;120 ≤150, f) &gt;150 ≤180, g) &gt;180 ≤210, h) &gt;210 ≤240 and i) &gt;240. Placentome size data was grouped by these categories. Descriptive statistics were generated for diameter for each gestational age category. All statistical analyses were run with the SAS program (2013). In all nine categories, placentome size was larger than reported for Bos taurus cows and smaller than reported in Bos indicus cows. In conclusion, placentome size in the sampled Bos taurus x Bos indicus cows was intermediate between that of the two source breeds. This confirms that existing reference tables for Bos taurus and Bos indicus purebreds are not accurate for crossbreeds.

Plasma concentrations of buprenorphine administered via matrix-type transdermal patches applied at three different anatomical locations in healthy adult horses.

Anatomical location-dependent differences in transdermal opioid penetration are well described in human patients. Although this has been investigated in horses with fentanyl, there is no literature available on location-dependent plasma buprenorphine concentrations when administered as a transdermal matrix-type patch. This study aims to compare the plasma concentrations achieved from the matrix-type transdermal buprenorphine patches placed at different anatomical sites (metacarpus, gaskin, and ventral tail base) in healthy adult horses. This is a randomized experimental study with a Latin square design. Six adult horses were given each of three treatments with a minimum 10-day washout period. For each treatment, two 20 μg h-1 matrix-type buprenorphine patches were applied to the ventral aspect of the tail base (TailTDP), metacarpus region (MetacarpusTDP), or gaskin region (GaskinTDP). Whole blood samples (for determination of buprenorphine concentration) and physiological variables were collected before (0 h) and at 0.5, 2, 4, 6, 8, 10, 12, 16, 24, 32, 48, 56, 72, 96 and 120 h after patches were applied. The patches were removed 96 h following placement and were analyzed for residual buprenorphine content. Buprenorphine concentrations were measured in plasma by LC-MS/MS. A mixed-effects model was used to analyze the physiological variables. Between the three treatment groups, there was no change in physiological variables across timepoints as compared to baseline and when compared to each other in a single horse and between horses (p > 0.3). When comparing all three locations, the buprenorphine uptake was observed to be more consistent with respect to measurable plasma concentrations >0.1 ng ml-1 when applied to the ventral aspect of the tail base. In the TailTDP group, the mean plasma buprenorphine concentrations were >0.1 ng ml-1 from 2 to 32 h. The highest group mean was 0.25 ng ml-1 noted at 4 h. The metacarpal and gaskin regions presented more erratic and inconsistent buprenorphine uptake and plasma concentrations as compared to the ventral aspect of the tail base. Further research must be directed at investigating the optimal dose, achievable duration of analgesia, change in measurable plasma concentrations, and behavioral and systemic effects.

Leishmania in skin of Rattus rattus from the urban area in the Corrientes city, Argentina

Objective: the objective of the present work was the detection of Leishmania sp. in Rattus rattus tail base skin through polymerase chain reaction (PCR) techniques. Material and Method: We analyzed 45 Rattus rattus skin samples from the urban area of the city of Corrientes in Argentina. The Leishmania spp detection was performed by nested PCR technique. Results: Leishmania DNA was detected in 22 samples out of 45 processed (49%) in the first round of amplification, and in 14 samples (31%) in the second round (31%). Conclusions: These results contribute to increase the existing information in our region on the possible relationship between Leishmania and Rattus rattus, considering the high prevalence found in skin added to the total absence of lesions. Other aspects should be further studied to establish the role of these animals in the epidemiological chain of the disease in an urban area endemic to leishmaniasis in other animal species.

Uplifting Antitumor Immunotherapy with Lymph-Node-Targeted and Ratio-Controlled Codelivery of Tumor Cell Lysate and Adjuvant.

Cancer vaccines provide a potential strategy to cure patients. Their clinical utilization and efficacy is, however, limited by incomplete coverage of tumor neoantigens and unspecific and restricted activation of dendritic cells (DCs). Tumor cell lysates (TCLs) containing a broad spectrum of neoantigens, while are considered ideal in formulating personalized vaccines, induce generally poor antigen presentation and transient antitumor immune response. Here, intelligent polymersomal nanovaccines (PNVs) that quantitatively coload, efficiently codeliver, and responsively corelease TCL and CpG adjuvant to lymph node (LN) DCs are developed to boost antigen presentation and to induce specific and robust antitumor immunity. PNVs carrying CpG and ovalbumin (OVA) markedly enhance the maturation, antigen presentation, and downstream T cell activation ability of bone-marrow-derived dendritic cells and induce strong systemic immune response after tail base injection. Remarkably, PNVs carrying CpG and TCL cure 85% of B16-F10 melanoma-bearing mice and generate long-lasting anticancer immune memory at a low dose, protecting all cured mice from tumor rechallenge. These LN-directed PNVs being highly versatile and straightforward opens a new door for personalized cancer vaccines.

Phenotypic analysis of ataxia in spinocerebellar ataxia type 6 mice using DeepLabCut

This study emphasizes the benefits of open-source software such as DeepLabCut (DLC) and R to automate, customize and enhance data analysis of motor behavior. We recorded 2 different spinocerebellar ataxia type 6 mouse models while performing the classic beamwalk test, tracked multiple body parts using the markerless pose-estimation software DLC and analyzed the tracked data using self-written scripts in the programming language R. The beamwalk analysis script (BAS) counts and classifies minor and major hindpaw slips with an 83% accuracy compared to manual scoring. Nose, belly and tail positions relative to the beam, as well as the angle at the tail base relative to the nose and tail tip were determined to characterize motor deficits in greater detail. Our results found distinct ataxic abnormalities such as an increase in major left hindpaw slips and a lower belly and tail position in both SCA6 ataxic mouse models compared to control mice at 18 months of age. Furthermore, a more detailed analysis of various body parts relative to the beam revealed an overall lower body position in the SCA684Q compared to the CT-longQ27PC mouse line at 18 months of age, indicating a more severe ataxic deficit in the SCA684Q group.

Infrared Thermographic Imaging as a Tool to Assess Inflammatory and Ischemic Response With Rubber Ring Tail Docking in Suffolk and Hampshire Lambs (Ovis Aries)

ABSTRACT Tail docking in lambs is associated with an acute inflammatory and ischemic response correlated to pain. The present study sought to quantify these responses by utilizing infrared thermographic imaging (IRT) after tail docking lambs. Images were taken for each lamb before tail docking (T0), within a minute after the band was placed (T1), at 5 minutes (T5), and 15 minutes (T15) respectively and analyzed for pixel intensity in areas on the lamb’s rump, tail base, and two locations below the docking band. The pixel intensity at 2 cm below the docking band did significantly decrease (p < 0.05) over the course of the study at 15 minutes, indicating the presence of ischemia, and a significant decrease in the pixel intensity of the rump and tail base was observed. The closest location to the rubber ring showed the presence of inflammation as an indirect indicator of acute pain . IRT is a valuable tool in the detection of inflammation and ischemic areas and has the potential to be used to quantify and measure the experience of inflammation and pain after tail docking.

Abstract 4135: First demonstration of magnetic particle imaging for sentinel lymph node identification

Abstract Sentinel Lymph Node (LN) biopsy involves the identification and surgical removal of the first LN(s) that drain from a primary tumor to evaluate for metastasis by histopathology [1]. For several tumor types, the standard of care is to manage the regional LN basin separately from the primary tumor. For head and neck cancer, melanoma, and complex breast cancer cases, pre-surgical imaging is required to determine the number and location of LN(s) to remove. Most sentinel LN biopsies are performed with nuclear imaging, which relies on short-lived radiotracers and can have poor image quality, making it challenging to identify sentinel LNs in complex anatomies. An alternative and non-inferior workflow uses a non-radioactive iron oxide magnetic tracer (ferucarbotran) with a magnetic probe [2], however this tool can only be used intraoperatively. In this abstract we introduce magnetic particle imaging (MPI) as a pre-surgical imaging technology that detects iron oxides with high sensitivity at mm-scale resolution [3]. Our objective is to demonstrate that MPI provides sensitive and quantitative tracking of ferucarbotran pharmacokinetics from four anatomical sites to primary draining LNs in mice. Methods: Ferucarbotran was administered intradermally to C57BL/6 mice at a standard clinical dose of 0.675 mg Fe/kg to the forepaw, hindpaw, or base of tail, or tongue (n = 4). Full-body 2D and 3D imaging was performed after 20 mins, 24 h, and 48 h, and 144 h using MOMENTUM imager (Magnetic Insight Inc.). MPI signal was quantified at the injection site and draining LNs. LNs of interest were extracted to verify MPI signals ex vivo then were processed for Perl’s Prussian iron staining. Results: After 20 minutes, MPI signal was seen at the injection site and primary LNs. The pharmacokinetics of ferucarbotran to LNs varied based on administration site. For hindpaw, signal was present in the popliteal LN (1.4% of tracer). For forepaw, ferucarbotran accumulated in the primary axillary LN (9%). For base of the tail, signal was observed in inguinal LN (2%). For tongue, MPI signal was detected in cervical LNs (14%). In all mice, MPI signal at the injection site decreased over time and signal in primary LNs persisted for at least 6 days. Conclusions: We demonstrated MPI is a quantitative, hotspot imaging technique for identifying primary LNs. As iron oxide tracer pharmacokinetics varies with injection site, this imaging technique could provide fundamental information required for surgical planning. Unlike nuclear imaging, persistence of MPI signal for several days provides tremendous flexibility in clinical workflow and introduces the potential for an image-guide delayed SLN biopsy [4] . This preclinical LN imaging is timely as our team is actively building and testing the world’s first large-bore, clinical-scale MPI scanner.[1] Leong SP, Clin Exp Metastasis (2022). [2] Alvarado MD, et al. Ann Surg Oncol (2019). [3] Sarnitas EU, et al. J Magn Reson (2014). [4] Karakatsanis A, et al. Ann Surg Oncol (2023). Citation Format: Olivia C. Sehl, A. Rahman Mohtasebzadeh, Kelvin Guo, Petrina Kim, Benjamin Fellows, Marcela Weyhmiller, Paula J. Foster, Patrick W. Goodwill, Joan M. Greve. First demonstration of magnetic particle imaging for sentinel lymph node identification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4135.

Evaluation of physical variables, thermal nociceptive threshold testing and pharmacokinetics during placement of transdermal buprenorphine matrix-type patch in healthy adult horses.

Matrix type transdermal buprenorphine patches have not been investigated in horses and may provide an effective means of providing continuous pain control for extended period and eliminating venous catheterization. Assessment of the physiological variables (heart rate, respiratory rate, body temperature) and thermal nociceptive threshold testing, and describing the pharmacokinetic profile of transdermal buprenorphine matrix-type patch (20 μg h-1 and 40 μg h-1 dosing) in healthy adult horses. Randomised experimental study with a Latin-square design. Six adult healthy horses received each of the three treatments with a minimum 10 day washout period. BUP0 horses did not receive a patch (control). BUP20 horses received one patch (20 μg h-1) applied on the ventral aspect of the tail base resulting in a dose of 0.03-0.04 μg kg-1 h-1. BUP40 horses received two patches placed alongside each other (40 μg h-1) on the tail base resulting in a dose of 0.07-0.09 μg kg-1 h-1. Whole blood samples (for determination of buprenorphine concentration), physiological variables and thermal threshold testing were performed before (0 h) and at 2, 4, 8, 12, 16, 24, 32, 40, 48, 56, 64, 72, and 96 h after patch application. The patches were removed 72 h following placement and were analyzed for residual buprenorphine content. Between the three groups, there was no change in physiological variables across timepoints as compared to baseline (p > 0.1). With the higher dose, there was a significant increase in thermal thresholds from baseline values from 2 h until 48 h and these values were significantly higher than the group receiving the lower patch dose for multiple timepoints up to 40 h. 40 μg h-1 patch led to consistent measurable plasma concentrations starting at 2 h up to 96 h, with the mean plasma concentrations of > 0.1 ng/ml from 4 h to 40 h. 20 μg h-1 and 40 μg h-1 patch doses were well tolerated by all horses. At higher dose, plasma buprenorphine concentrations were more consistently measurable and blunted thermal thresholds for 48 h vs. 32 h with 20 μg h-1 dosing as compared to control.

Androgen Receptors in the Dermal Glands of Male and Female Ouachita Dusky Salamanders

Synopsis The presence of androgens in female development is an important, yet often overlooked, topic. We tested for the presence of androgen receptors (ARs) in the dermal glands of male and female Desmognathus brimleyorum, a plethodontid salamander. This species engages in a courtship behavior called the tail-straddling walk. During this process, communication between males and females is hypothesized to be facilitated by pheromones secreted from modified granular glands (MGGs) on the dorsal tail base, where the female's chin is positioned. These glands are present not only dorsally but also laterally and ventrally on the tail of both males and females. Using immunohistochemistry with a polyclonal antibody, ARs were located in the MGGs of both sexes. Males had a higher percentage of immunopositive cells per MGG than females. The presence of ARs in both sexes highlights the similarity between MGGs in males and females and suggests androgens play a role in female gland function. Furthermore, our results suggest courtship communication is bidirectional, and females have a more active role, signaling the male, than previously described.