Comparison between Bilateral Ultrasound-Guided Quadratus Lumborum Block and Sacrococcygeal Epidural in Cats Undergoing Ovariectomy

BACKGROUND

Ultrasound-guided quadratus lumborum block (QLB) and sacrococcygeal epidural anaesthesia (ScE) have been used for neutering cats, providing effective pain relief.

OBJECTIVES

To compare the effects of the QLB with those of ScE in cats undergoing ovariectomies.

METHODS

Feral cats undergoing ovariectomy were premedicated with dexmedetomidine (20 μg kg-1) and methadone (0.2 mg kg-1) intramuscularly. Anaesthesia was induced with 2-4 mg kg-1 of propofol intravenously and maintained with isoflurane in oxygen. The cats were randomly allocated to the groups QLB (bilateral QLB with 0.4 mL kg-1 of 0.25% bupivacaine) and ScE (0.3 mL kg-1 of 0.25% bupivacaine). Hemodynamic data and analgesia rescue were collected at four intraoperative periods. The pain scale and motor block were assessed in both groups during the postoperative period.

RESULTS

The ScE results in increased hypotension, prolonged extubation time, and higher postoperative motor block than the QLB (p < 0.05). The QLB and ScE groups required a similar number of intraoperative rescues and presented the same postoperative pain scale classification.

CONCLUSIONS

The QLB with 0.25% bupivacaine is a potential alternative to ScE with 0.25% bupivacaine in perioperative pain management in elective cat ovariectomy. The QLB promoted less hypotension and postoperative motor block when compared with the ScE group.

Investigating the Architecture and Characteristics of Asian Hornet Nests: A Biomimetics Examination of Structure and Materials

This study investigates the internal architecture of Asian hornet nests (AHNs) using advanced imaging techniques, such as CT scanning and X-ray radiography, to understand their construction and function. The primary objective and significance of this study centre on drawing inspiration from the creative way Asian hornets construct their nests, with a particular focus on the architecture, design, functionality, and building materials of these nests. The architectural principles governing the construction of these nests, such as the arrangement of hexagonal cells, pedicels for load bearing, and adhesive materials, serve as a source of inspiration for innovative and sustainable design practices. The pedicels in Asian hornet nests play a crucial role in transferring load and ensuring stability. Additionally, AHNs' adhesion to tree branches is essential for preventing collapse, and the pedicels provide necessary structural support. The knowledge gained from studying AHNs' internal architecture could be applied directly to the architecture and civil engineering fields to improve structure stability and durability. The microstructure analysis of the paper-like material that hornets produce to build their nests indicates a complex and heterogeneous structure, composed of various plant fragments and fibres. This unique composition creates intricate grooves and pores, which are essential for regulating temperature and humidity levels within the outer envelope of the nest. The study of Asian hornet nests' internal structure demonstrated that nature's engineering principles inspire the design of durable and resilient structures in the construction industry. Civil engineers can incorporate similar principles into their designs to enhance the structural integrity and performance of buildings, bridges, and other infrastructure.

Mechanical osteoarthritis of the hip in a one medicine concept: a narrative review

Human and veterinary medicine have historically presented many medical areas of potential synergy and convergence. Mechanical osteoarthritis (MOA) is characterized by a gradual complex imbalance between cartilage production, loss, and derangement. Any joint instability that results in an abnormal overload of the joint surface can trigger MOA. As MOA has a prevailing mechanical aetiology, treatment effectiveness can only be accomplished if altered joint mechanics and mechanosensitive pathways are normalized and restored. Otherwise, the inflammatory cascade of osteoarthritis will be initiated, and the changes may become irreversible. The management of the disease using non-steroidal anti-inflammatory drugs, analgesics, physical therapy, diet changes, or nutraceuticals is conservative and less effective. MOA is a determinant factor for the development of hip dysplasia in both humans and dogs. Hip dysplasia is a hereditary disease with a high incidence and, therefore, of great clinical importance due to the associated discomfort and significant functional limitations. Furthermore, on account of analogous human and canine hip dysplasia disease and under the One Medicine concept, unifying veterinary and human research could improve the well-being and health of both species, increasing the acknowledgement of shared diseases. Great success has been accomplished in humans regarding preventive conservative management of hip dysplasia and following One Medicine concept, similar measures would benefit dogs. Moreover, animal models have long been used to better understand the different diseases' mechanisms. Current research in animal models was addressed and the role of rabbit models in pathophysiologic studies and of the dog as a spontaneous animal model were highlighted, denoting the inexistence of rabbit functional models to investigate therapeutic approaches in hip MOA.

Establishment of an ultrasound-guided protocol for the assessment of hip joint osteoarthritis in rabbits-A sonoanatomic study

Ultrasound (US) has emerged as one of the most applied imaging tools to diagnose musculoskeletal disorders and assist in guided intra-articular administrations. Nevertheless, in evaluating the rabbit hip joint, there is a need for an ultrasonographic approach. Therefore, this study aimed to describe the hip sonoanatomy, develop and validate a US-guided protocol to assess the hip joint in rabbits and apply this protocol in vivo. This study was carried out in three phases, phase I: a pilot cadaveric study, to assess the applicability of different US approaches in the hip of rabbits and, consequently, develop a detailed US-guided protocol (2 rabbit cadavers, n = 4 hips); phase II: validation of the established US-guided protocol through a numerical scoring system in healthy joints (11 rabbit cadavers, n = 22 hips), and, lastly, phase III: application of the US-guided protocol in vivo in osteoarthritic joints (5 rabbits, n = 5 hips). A total of six planes were validated, two in the ventral approach and four in the dorsal approach. The ventral transverse plane was deemed more informative regarding the hip joint sonoanatomy, enabling the identification of a greater number of structures when compared to the other planes. Nevertheless, this study suggested that the isolated application of a plane was deemed insufficient for a complete and detailed evaluation of the hip joint anatomy, rendering it necessary to employ other planes complementarily. Furthermore, the established US-guided protocol allowed a definitive diagnosis of OA, and osteophytes and capsular hypertrophy were among the defects most frequently detected. This novel study provided US anatomical landmarks for forthcoming therapeutic research and monitoring of OA development, granting the accurate identification of osseous and cartilaginous defects.

Femoral Neck Thickness Index as an Indicator of Proximal Femur Bone Modeling

The alteration in the shape of the femoral neck is an important radiographic sign for scoring canine hip dysplasia (CHD). Previous studies have reported that the femoral neck thickness (FNT) is greater in dogs with hip joint dysplasia, becoming progressively thicker with disease severity. The main objective of this work was to describe a femoral neck thickness index (FNTi) to quantify FNT and to study its association with the degree of CHD using the Fédération Cynologique Internationale (FCI) scheme. A total of 53 dogs (106 hips) were randomly selected for this study. Two examiners performed FNTi estimation to study intra- and inter-examiner reliability and agreement. The paired t-test, the Bland-Altman plots, and the intraclass correlation coefficient showed excellent agreement and reliability between the measurements of the two examiners and the examiners' sessions. All joints were scored in five categories by an experienced examiner according to FCI criteria. The results from examiner 1 were compared between FCI categories. Hips that were assigned an FCI grade of A (n = 19), B (n = 23), C (n = 24), D (n = 24), and E (n = 16) had a mean ± standard deviation FNTi of 0.809 ± 0.024, 0.835 ± 0.044, 0.868 ± 0.022, 0.903 ± 0.033, and 0.923 ± 0.068, respectively (ANOVA, p < 0.05). Therefore, these results show that FNTi is a parameter capable of evaluating proximal femur bone modeling and that it has the potential to enrich conventional CHD scoring criteria if incorporated into a computer-aided diagnosis capable of detecting CHD.

Femoral parallelism: evaluation and impact of variation on canine hip dysplasia assessment

Adequate radiographic positioning on the X-ray table is paramount for canine hip dysplasia (HD) screening. The aims of this study were to evaluate femoral parallelism on normal ventrodorsal hip extended (VDHE) view and the effect of femoral angulation (FA) on Norberg Angle (NA) and Hip Congruency Index (HCI). The femoral parallelism was evaluated comparing the alignment of the long femoral axis with the long body axis in normal VDHE views and the effect of FA on NA and HCI on repeated VDHE views with different levels of FA. The femoral long axis in normal VDHE views showed a ranged of FA from -4.85° to 5.85°, mean ± standard deviation (SD) of -0.06 ± 2.41°, 95% CI [-4.88, 4.76°]. In the paired views, the mean ± SD femur adduction of 3.69 ± 1.96° led to a statistically significant decrease NA, and HCI, and femur abduction of 2.89 ± 2.12 led to a statistically significant increase in NA and HCI (p < 0.05). The FA differences were also significantly correlated with both NA differences (r = 0.83) and HCI differences (r = 0.44) (p < 0.001). This work describes a methodology that allows evaluation of femoral parallelism in VDHE views and the results suggest that femur abduction yielded more desirable NA and HCI values and adduction impaired NA and HCI values. The positive linear association of FA with NA and HCI allows the use of regression equations to create corrections, to reduce the influence of poor femoral parallelism in the HD scoring.

Artificial Intelligence in Veterinary Imaging: An Overview

Artificial intelligence and machine learning have been increasingly used in the medical imaging field in the past few years. The evaluation of medical images is very subjective and complex, and therefore the application of artificial intelligence and deep learning methods to automatize the analysis process would be very beneficial. A lot of researchers have been applying these methods to image analysis diagnosis, developing software capable of assisting veterinary doctors or radiologists in their daily practice. This article details the main methodologies used to develop software applications on machine learning and how veterinarians with an interest in this field can benefit from such methodologies. The main goal of this study is to offer veterinary professionals a simple guide to enable them to understand the basics of artificial intelligence and machine learning and the concepts such as deep learning, convolutional neural networks, transfer learning, and the performance evaluation method. The language is adapted for medical technicians, and the work already published in this field is reviewed for application in the imaging diagnosis of different animal body systems: musculoskeletal, thoracic, nervous, and abdominal.

Active learning for data efficient semantic segmentation of canine bones in radiographs

X-ray bone semantic segmentation is one crucial task in medical imaging. Due to deep learning's emergence, it was possible to build high-precision models. However, these models require a large quantity of annotated data. Furthermore, semantic segmentation requires pixel-wise labeling, thus being a highly time-consuming task. In the case of hip joints, there is still a need for increased anatomic knowledge due to the intrinsic nature of the femur and acetabulum. Active learning aims to maximize the model's performance with the least possible amount of data. In this work, we propose and compare the use of different queries, including uncertainty and diversity-based queries. Our results show that the proposed methods permit state-of-the-art performance using only 81.02% of the data, with O(1) time complexity.

Acetabular Coverage Area Occupied by the Femoral Head as an Indicator of Hip Congruency

Accurate radiographic screening evaluation is essential in the genetic control of canine HD, however, the qualitative assessment of hip congruency introduces some subjectivity, leading to excessive variability in scoring. The main objective of this work was to validate a method-Hip Congruency Index (HCI)-capable of objectively measuring the relationship between the acetabulum and the femoral head and associating it with the level of congruency proposed by the Fédération Cynologique Internationale (FCI), with the aim of incorporating it into a computer vision model that classifies HD autonomously. A total of 200 dogs (400 hips) were randomly selected for the study. All radiographs were scored in five categories by an experienced examiner according to FCI criteria. Two examiners performed HCI measurements on 25 hip radiographs to study intra- and inter-examiner reliability and agreement. Additionally, each examiner measured HCI on their half of the study sample (100 dogs), and the results were compared between FCI categories. The paired t-test and the intraclass correlation coefficient (ICC) showed no evidence of a systematic bias, and there was excellent reliability between the measurements of the two examiners and examiners’ sessions. Hips that were assigned an FCI grade of A (n = 120), B (n = 157), C (n = 68), D (n = 38) and E (n = 17) had a mean HCI of 0.739 ± 0.044, 0.666 ± 0.052, 0.605 ± 0.055, 0.494 ± 0.070 and 0.374 ± 0.122, respectively (ANOVA, p < 0.01). Therefore, these results show that HCI is a parameter capable of estimating hip congruency and has the potential to enrich conventional HD scoring criteria if incorporated into an artificial intelligence algorithm competent in diagnosing HD.

Effect Of Elbow Angle And Weight-Bearing On The Evaluation Of Joint Congruence In Dogs

Joint congruence is relevant for the assessment of elbow dysplasia, a development disorder in dogs. However, quantification of its variation with joint angle and weight bearing, important factors in quadrupedal locomotion, is lacking. Our objective was to estimate those effects on the alignment of humeroradioulnar joint surfaces. The usual protocol for screening elbow dysplasia, including mediolateral extended and flexed elbow views, was preceded by a weight-bearing lateromedial standing radiographic view, without sedation. Minimum distances were measured at established points of the humeroradioulnar joints classified with a grade zero of dysplasia. Sixty elbows (30 Portuguese Pointer dogs) were studied. The joint space between the anconeal process and the ulnar trochlear notch increased with flexion, decreasing with weight bearing (P<0.001). The distance between the humeral trochlea and the trochlear notch at the widest point, increased with weight bearing, while it decreased with flexion. Step and distance between the radial head and the base of the medial coronoid process increased with flexion and decreased with weight bearing. At this point, physiological changes occurred at the humeroulnar joint space. The methodology allowed to quantify the variations on joint spaces with the elbow angle and weight bearing, important for the interpretation of congruence in diagnosis and treatment of dysplasia. Reference absolute and indexed values obtained allow future comparisons with other breeds and dysplastic dogs. Physiological variations denoted that radioulnar joint became more incongruent under flexion, and more congruent under weight bearing, while humeroulnar joint became more congruent under flexion, and more incongruent under weight bearing.

Early hip laxity screening and later canine hip dysplasia development

Background and Aim:

Passive hip laxity (PHL) is considered the primary risk factor for canine hip dysplasia (HD) and is estimated, in stress hip radiographs, using the distraction index (DI). The study aimed to associate the early PHL using the hip Distractor of University of Trás-os-Montes and Alto Douro (DisUTAD) and the late HD grades.

Materials and Methods:

A total of 41 dogs (82 hips) were submitted to a follow-up study. First, between 4 and 12 months of age, dogs were radiographed using the DisUTAD hip distractor and were determined the DI for each hip joint. Then, after 12 months of age, dogs were reevaluated for HD using the conventional hip ventrodorsal projection and hips were evaluated for HD using the Fédération Cynologique Internationale (FCI) scoring system.

Results:

Hips of dogs’ in the second examination with FCI grades of A (n=28), B (n=11), C (n=22), and D and E (n=21) had an early DI of 0.32±0.1, 0.38±0.08, 0.50±0.12, and 0.64±0.11, respectively. Statistical analysis using the general linear model univariate, with the DI as dependent variable and the FCI grades, side and sex as fixed factors, and the post hoc Bonferroni correction test showed significant differences among FCI grades (p<0.05).

Conclusion:

These results show the association between early DI and the late FCI HD grades and the DisUTAD is recommended for the early canine HD diagnosis.

Effects of testosterone and exercise training on bone microstructure of rats

Background and Aim:

Male hypogonadism results from failure to produce physiological levels of testosterone. Testosterone in men is essential in masculine development, sperm production, and adult man’s health. Osteoporosis is one of the consequences of hypogonadism. Regular physical exercise and exogenous testosterone administration are frequently used to prevent or treat this condition. This study aimed to understand the effects of lifelong exercise training and testosterone levels (isolated and together) in the main bone structure parameters.

Materials and Methods:

A total of 24 rats were used and randomly divided into four groups: Control group (CG; n=6), exercised group (EG, n=6), testosterone group (TG, n=6), and testosterone EG (TEG, n=6). A micro-computed tomography equipment was used to evaluate 15 bone parameters.

Results:

Both factors (exercise training and testosterone) seem to improve the bone resistance and microstructure, although in different bone characteristics. Testosterone influenced trabecular structure parameters, namely, connectivity density, trabecular number, and trabecular space. The exercise promoted alterations in bone structure as well, although, in most cases, in different bone structure parameters as bone mineral density and medullar mineral density.

Conclusion:

Overall, exercise and testosterone therapy seems to have a synergistic contribution to the general bone structure and resistance. Further studies are warranted, comparing different individual factors, as gender, lifestyle, or testosterone protocols, to constantly improve the medical management of hypogonadism (and osteoporosis).

A description of an ultrasound-guided technique for a quadratus lumborum block in the cat: a cadaver study

OBJECTIVES

To describe the ultrasonographic (US) anatomy of the sublumbar region at the level of second lumbar vertebra (L2), to assess the feasibility of US-guided quadratus lumborum (QL) injections and to evaluate the dye distribution pattern in feline cadavers.

STUDY DESIGN

Descriptive feline cadaver study.

ANIMALS

A total of eight cat cadavers.

METHODS

Using a linear probe (6-14 MHz), with the cadavers in lateral recumbency, the QL and psoas muscles (Pm) were identified at the level of L2 and landmarks recorded. Using an in-plane technique, a spinal needle was inserted in a ventrodorsal direction to reach the interfascial plane between the QL and Pm. Using a ropivacaine, dye and iohexol solution, a total volume of 0.4 mL kg^-1 was injected. Computed tomography (CT) scanning and anatomic dissection were performed to evaluate the spread of injectate. Presence of dye on the sympathetic trunk was compared between assessment methods using kappa coefficient of agreement (κ).

RESULTS

Using US guidance, the QL-Pm interfascial plane was identified and dye solution was present in the target fascial plane in all animals. Injectate was distributed on the ventral roots of the spinal nerves between the first and third lumbar vertebrae in 6/8 cats, and on the sympathetic trunk from the thirteenth thoracic to the third lumbar vertebrae in 7/8. Dye was found on the major splanchnic nerve in 7/8 cats and on the minor splanchnic nerve and coeliac ganglion pathways in all animals. Agreement between dissection and CT images dye distribution on the sympathetic trunk was κ = 0.72.

CONCLUSIONS AND CLINICAL RELEVANCE

The US-guided QL injection was feasible and injectate was present in the QL-Pm interfascial plane in all feline cadavers. In vivo studies are warranted to evaluate the analgesic efficacy of this technique for abdominal surgical procedures.

Digital Analysis of Subtrochlear Sclerosis in Elbows Submitted for Dysplasia Screening

Ulnar trochlear notch (UTN) subchondral bone sclerosis is observed in elbow dysplasia (ED) associated with the medial coronoid disease. However, its evaluation is based on a simple visual examiner assessment of bone radio-opacity level and is considered subjective. The purpose of this study was to objectively characterize the radiographic opacity of the ulnar trochlear notch (UTN) subchondral bone in mediolateral elbow projections classified, using the International Elbow Working Group guidelines. Records and mediolateral flexed elbow images from the Danish Kennel Club database for the ED screening scheme between 2012 and 2018 were available. Of the dogs in the database, those with an ED-negative status in the left limb were identified. From these, 20 dogs each having a status free from ED, or with Grade 1, 2, or 3 in the right limb, were randomly chosen. Joints with primary ununited anconeal process were excluded from the sample. A template was developed using the ImageJ software, for computer UTN sclerosis analysis. It was overlaid onto each image to define five regions of interest (ROIs): ROI-1, distal UTN; ROI-2, middle UTN; ROI-3, caudal UTN; ROI-4, cortical bone; and ROI-5, bone marrow. Mean pixel intensity for each UTN ROI was divided by the mean pixel intensity of ROI-4 to normalize the data. The mean ± standard deviation (SD) of the normalized pixel intensity in the disease joints (ED Grades 1, 2, and 3) was 1.18 ± 0.17, 1.03 ± 0.12, and 0.92 ± 0.09 for ROIs 1, 2, and 3, respectively. The corresponding values for the contralateral normal left joints were 1.16 ± 0.17, 1.01 ± 0.1, and 0.91 ± 0.08. There was a significant difference (P < 0.05) in the normalized mean pixel intensity in dysplastic vs. non-dysplastic elbow joints for ROIs 1 and 2. The raw mean pixel intensity from right and left cortical and marrow bone ROIs sometimes showed relatively large differences. Digital radiography is associated with exposure and post-processing variabilities. Differences in apparent radio-opacity (as indicated by pixel intensity) though statistically significant in dysplastic joints compared with contralateral normal joints are slight and are thus problematic for computer-aided assessments of UTN sclerosis.

Measurement of the Femoral Anteversion Angle in Medium and Large Dog Breeds Using Computed Tomography

To promote the development of an optimally functional total hip prosthesis for medium and large dog breeds, accurate measurements of the normal anatomy of the proximal femur and acetabular retroversion are essential. The aim of the current study was to obtain precise normal values of the femoral anteversion angle using computed tomography on cadavers of mature dogs with normal hip joints of both medium and large breeds. Based on the length of their femora 58 dogs were allocated either to group I: ≤195 mm or group II: >195 mm. In the study the femoral anteversion angle (FAA) was measured on each femur using multi-slice spiral computed tomography (CT). The data were processed as multi-planar and three-dimensional reconstructions using Advantage Workstation software. The CT measurements showed that the mean ± standard deviation (SD) FAA of group I was 31.34 ± 5.47° and in group II it was 31.02 ± 4.95°. There were no significant mean difference associations between the length of the femur and the femoral neck angle in either group (P > 0.05). The data suggest that a prosthesis FAA of 31 degrees would be suitable for a wide range of dog sizes.

Comparison of Two Distraction Devices for Assessment of Passive Hip Laxity in Dogs

Canine hip dysplasia is the most common orthopedic developmental condition in the dog and early hip laxity is the main risk factor. The importance of hip laxity in young animals in the development of hip dysplasia is unanimously recognized among researchers and veterinarians due to its medical applicability in terms of disease control and prevention. In the market, there is some certified hip distractors to promote joint laxity. However, the clinical use of some of these distractors complies with a set of usage rules, that can limit its medical application. In this study was compared the technical quality of radiographs and hip distraction using a certified hip distractor (CertD) and Dis-UTAD in 104 dogs (208 joints). The mean pelvic tilting of 1.5 ± 1.6° and 1.5 ± 1.8° were similar when using the CertD and the Dis-UTAD distractors, respectively (P > 0.05). In the CertD sample, the mean hip distraction index (DI) was 0.46 ± 0.17 and in the Dis-UTAD 0.46 ± 0.16; the mean DI differences was 0.001 ± 0.045, resulting in a non-significant paired t-test (P = 0.65) and a significant intraclass correlation coefficient of 0.96, with the 95% lower limit confidence interval of 0.95 (P < 0.05). The statistical power analysis showed a very low distraction index difference effect size. The results suggest that the statistical reproducibility of CertD hip distraction by the Dis-UTAD and the DI mean differences of 0.001 might be considered without clinical importance. The Dis-UTAD might be considered adequate to promote dog hip laxity.

Distraction index measurement on the dog's hip joint using a dedicated software

ABSTRACT The aim of this study was to test the accuracy of a new automated computer software tool for the assessment of passive hip laxity. The hip laxity was estimated using the dedicated computer software by two blinded evaluators, one previously trained and one without specific training for distraction index measurement, in two independent sessions using 230 hip joints from 115 dogs that underwent screening for passive hip laxity using the distraction view. Previously, all of these radiographs were sent to PennHIP Analysis Center for an official distraction index record. The measurement repeatability of the two sessions was adequate for both evaluators. The reproducibility of the official distraction index measurement, mean distraction index±standard deviation 0.44±0.15, was adequate (P>0.05) for the trained evaluator, 0.44±0.15, and non-adequate (P<0.05), for the non-trained evaluator 0.47±0.17. The distraction index measurement tool proposed can be used with confidence for hip laxity evaluation by trained evaluators, as it provided good repeatability and reproducibility of official reports. The simplicity of the process described leads to a less time-consuming and more affordable procedure.

Hands-Free Conventional Radiographic Ventrodorsal Hip Extended View

Hip dysplasia (HD) is an important hereditary orthopedic disease in the dog associated with osteoarthritis and inadequate welfare for affected animals. The radiographic ventrodorsal hip extended (VDHE) view is used worldwide to select the better animals for breeding. This view normally is performed with manual restraining of the dog to obtain radiographs with acceptable technical quality. The veterinarian exposition to ionizing radiation is inevitable. In this study, the technical quality of VDHE radiographs and hip measurements was compared in 65 dogs radiographed twice, one with the common veterinarian manual restraining and the other obtained using a hind limb holder device, without the veterinarian within the X-ray room. The variables studied were pelvic tilting, patella displacement index, Norberg angle (NA), and subluxation hip category. The results showed a random distribution of right and left pelvic tilting, patella lateral or medial displacement, and hip subluxation categories in both samples (P > 0.05). The holder device positioning showed a better pelvic symmetry (P < 0.05) and a similar patellar displacement (P > 0.05). The mean ± standard deviation of NA was 101.1° ± 6.2° and 100.9° ± 6.1° in the manual and holder device hind limb restraining, respectively (P > 0.05), and the lower limit of 95% confidence interval of intraclass correlation coefficient was >0.75. These results showed statistical reproducibility of NA measurements by the hind limb holder device, and the examiner was protected from exposure to ionizing radiation within the X-ray room.

Anatomy and Imaging of Rat Prostate: Practical Monitoring in Experimental Cancer-Induced Protocols

The rat has been frequently used as a model to study several human diseases, including cancer. In many research protocols using cancer models, researchers find it difficult to perform several of the most commonly used techniques and to compare their results. Although the protocols for the study of carcinogenesis are based on the macroscopic and microscopic anatomy of organs, few studies focus on the use of imaging. The use of imaging modalities to monitor the development of cancer avoids the need for intermediate sacrifice to assess the status of induced lesions, thus reducing the number of animals used in experiments. Our work intends to provide a complete and systematic overview of rat prostate anatomy and imaging, facilitating the monitoring of prostate cancer development through different imaging modalities, such as ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI).

Mast Cells in Mammary Carcinogenesis: Host or Tumor Supporters?

BACKGROUND/AIM

The effects of mast cells on carcinogenesis is not yet fully understood. This work aimed to disclose the role of mast cells in mammary carcinogenesis in a rat model.

MATERIALS AND METHODS

Mammary tumors were induced by the administration of N-methyl-N-nitrosourea (MNU) in three groups of rats. Animals from one group were treated with ketotifen immediately after MNU administration, and animals from another only received ketotifen after the development of the first mammary tumor. The biochemical profile was determined. Mammary tumors were evaluated by histopathology and immunohistochemistry.

RESULTS

Animals from ketotifen-treated groups developed fewer mammary tumors, higher number of mammary lesions and had lower histamine levels when compared to non-treated animals. Animals treated with ketotifen immediately after MNU exhibited the lowest proliferative and apoptotic indexes.

CONCLUSION

The mainly positive effect of the inhibition of mast cell degranulation seems to be the reduction of tumor proliferation when the mast cell degranulation was inhibited before tumor development.

Modulation of mammary tumor vascularization by mast cells: Ultrasonographic and histopathological approaches

AIMS

The inhibition of mast cells' degranulation may be an approach to prevent the formation of new vessels during the mammary carcinogenesis.

MATERIALS AND METHODS

Female Sprague-Dawley rats were randomly divided into five experimental groups. Mammary tumors were induced by intraperitoneal injection of N-methyl-N-nitrosourea (MNU). Animals from group II were treated with ketotifen for 18weeks immediately after the MNU administration, while animals from group III only received the ketotifen after the development of the first mammary tumor. Mammary tumors vascularization was assessed by ultrasonography (Doppler, B Flow and contrast-enhanced ultrasound) and immunohistochemistry (vascular endothelial growth factor-A).

KEY FINDINGS AND SIGNIFICANCE

Similar to what occurs in women with breast cancer, the majority of MNU-induced mammary tumors exhibited a centripetal enhancement order of the contrast agent, clear margin and heterogeneous enhancement. Ultrasonographic and immunohistochemical data suggest that the inhibition of mast cells' degranulation did not change the mammary tumors vascularization.

Electron Microscopy Findings in N-Methyl-N-Nitrosourea-Induced Mammary Tumors

Although the rat model of mammary tumors chemically induced by N-methyl-N-nitrosourea (MNU) has been frequently used by several research teams, there is a lack of ultrastructural studies in this field. The main aim of this work was to perform an ultrastructural characterization of MNU-induced mammary tumors in female rats. Some alterations previously reported in human mammary tumors, such as nucleus size and shape, accumulation of heterochromatin in the perinuclear region, and interdigitating cytoplasmic processes between cancer cells were also observed in MNU-induced mammary tumors. Although a low number of samples were analyzed by transmission electron microscopy in the present study, we consider that it may contribute to a better understanding of MNU-induced mammary carcinogenesis in a rat model. The ultrastructural characteristics of the two most frequently diagnosed mammary carcinomas described in the present work can be useful to differentiate them from other histological patterns. In addition, the loss of cytoplasm in neoplastic cells and formation of vacuoles were described.

Ultrasonography as the Gold Standard for In Vivo Volumetric Determination of Chemically-induced Mammary Tumors

BACKGROUND/AIM

In this study, we evaluated the dimensions and volume of rat mammary tumors and the association of these variables with tumor invasiveness.

MATERIALS AND METHODS

Tumors were measured by caliper and ultrasonography. Volume was determined by water displacement and by application of four formulas using tumor length (L), width (W) and depth (D) or tumor weight.

RESULTS

Results confirmed the data obtained in our previous work, where we verified that mammary tumors grow as oblate spheroids.

CONCLUSION

The determination of mammary tumor volume by applying the formula V=(4/3)×π×(L/2)×(L/2)×(D/2) is the best way to evaluate tumor volume in vivo. Beyond volume evaluation by water displacement, the determination on the basis of tumor weight is the most accurate way to evaluate tumor volume after animal sacrifice or tumor excision. According to our results, it is not possible to predict if a tumor is invasive or non-invasive by its dimensions, volume or weight. Future work in chemically-induced mammary cancer should use ultrasonography and water displacement or tumor weight to determine tumor volume in vivo and after animal sacrifice or tumor excision, respectively.

Long-term exercise training as a modulator of mammary cancer vascularization

BACKGROUND

Breast cancer remains a leading cause of death by cancer worldwide. It is commonly accepted that angiogenesis and the expression of angiogenic factors such as vascular endothelial growth factor-A (VEGF-A) is associated with the increased risk of metastasis and poor patient outcome.

OBJECTIVE

This work aimed to evaluate the effects of long-term exercise training on the growth and vascularization of mammary tumors in a rat model.

MATERIALS AND METHODS

Fifty female Sprague-Dawley rats were divided into four groups: two N-methyl-N-nitrosourea (MNU)-exposed groups (exercised and sedentary) and two control groups (exercised and sedentary). MNU was administered once, intraperitoneally at 7 weeks-old. Animals were then exercised on a treadmill for 35 weeks. Mammary tumors were evaluated using thermography, ultrasonography [Power Doppler (PDI), B Flow and contrast-enhanced ultrasound (CEUS)], and immunohistochemistry (VEGF-A).

RESULTS

Both, MNU sedentary and exercised groups showed 100% of tumor incidence, but exercised animals showed less tumors with an increased latency period. Exercise training also enhanced VEGF-A immunoexpression and vascularization (microvessel density, MVD) (p<0.05), and reduced histological aggressiveness. Ultrasound and thermal imaging analysis confirmed the enhanced vascularization of tumors on exercised animals.

CONCLUSION

Long-term exercise training increased VEGF-A expression, leading to enhanced tumor vascularization and reduced tumor burden, multiplicity and histological aggressiveness.

N-Methyl-N-nitrosourea as a mammary carcinogenic agent

The administration of chemical carcinogens is one of the most commonly used methods to induce tumors in several organs in laboratory animals in order to study oncologic diseases of humans. The carcinogen agent N-methyl-N-nitrosourea (MNU) is the oldest member of the nitroso compounds that has the ability to alkylate DNA. MNU is classified as a complete, potent, and direct alkylating compound. Depending on the animals' species and strain, dose, route, and age at the administration, MNU may induce tumors' development in several organs. The aim of this manuscript was to review MNU as a carcinogenic agent, taking into account that this carcinogen agent has been frequently used in experimental protocols to study the carcinogenesis in several tissues, namely breast, ovary, uterus, prostate, liver, spleen, kidney, stomach, small intestine, colon, hematopoietic system, lung, skin, retina, and urinary bladder. In this paper, we also reviewed the experimental conditions to the chemical induction of tumors in different organs with this carcinogen agent, with a special emphasis in the mammary carcinogenesis.

Emerging insights into the genetic basis of canine hip dysplasia

Canine hip dysplasia (CHD) is the most common inherited polygenic orthopedic trait in dogs with the phenotype influenced also by environmental factors. This trait was described in the dog in 1935 and leads to a debilitating secondary hip osteoarthritis. The diagnosis is confirmed radiographically by evaluating signs of degenerative joint disease, incongruence, and/or passive hip joint laxity. There is no ideal medical or surgical treatment so prevention based on controlled breeding is the optimal approach. The definitive CHD diagnosis based on radiographic examination involves the exposure to ionizing radiation under general anesthesia or heavy sedation but the image does not reveal the underlying genetic quality of the dog. Phenotypic expression of CHD is modified by environmental factors and dogs with a normal phenotype can be carriers of some mutations and transmit these genes to their offspring. Programs based on selection of dogs with better individual phenotypes for breeding are effective when strictly applied but remain inferior to the selection of dogs based on estimation of breeding values. Molecular studies for dissecting the genetic basis of CHD are ongoing, but progress has been slow. In the future, the recommended method to improve hip quality in controlled breeding schemes, which will allow higher selection pressure, would be based on the estimation of the genomic breeding value. Since 2012, a commercial DNA test has been available for Labrador Retrievers using a blood sample and provides a probability for development of CHD but we await evidence that this test reduces the incidence or severity of CHD.

Ultrasonographic evaluation of gastrocnemius muscle in a rat model of N-methyl-N-nitrosourea-induced mammary tumor

BACKGROUND/AIM

Ultrasonography is frequently used to study body tissues. Our aim was to evaluate by ultrasonography, gastrocnemius muscle wasting induced by cancer in a rat model of chemically-induced mammary tumor, muscular response to exercise.

MATERIALS AND METHODS

Female Sprague-Dawley rats were divided into as well as four groups. Groups I and II were injected with N-methyl-N-nitrosourea (MNU). Groups I and III performed endurance training on a treadmill. Gastrocnemius muscles were palpated for tonus evaluation. Gastrocnemius muscle and fibrous tissue between muscle and tibia were examined by ultrasonography. At necropsy, muscle was collected and weighed. Myostatin was assessed by immunoblotting.

RESULTS

The final body weight, gastrocnemius weight, length and width were similar among groups. Tone of muscle was higher in exercised animals. Myostatin was higher in MNU-treated groups. Echogenicity of muscle and fibrous tissue in group IV was higher than in other groups (p<0.05). Echogenicity of fibrous tissue was higher than echogenicity of muscle in all groups.

CONCLUSION

Our results showed that muscle ultrasonography is a useful tool to identify alterations in muscle structure. More studies are necessary for researchers to understand the influence of fat location in muscle ultrasonographic imaging.

Passive hip laxity in Estrela Mountain Dog--distraction index, heritability and breeding values

Two hundred and fifteen Estrela Mountain Dogs (EMD) were examined using the PennHIP method between 2002 and 2006. Passive hip laxity (PHL) was estimated calculating the distraction index (DI). Pedigree information was obtained from the Portuguese Kennel Club. The heritability and breeding values were estimated using the linear Animal Model. The DI, using as reference the worst joint of each animal, ranged from 0.15 to 1.12 (0.55 +/- 0.19). The PHL was equal in right and left sides, and was higher in females than in males (P > 0.05 and P <0.01 in the t-test, respectively). The estimated heritability was 0.83 +/- 0.11. The mean breeding values for PHL were stable in EMD born between 1991 and 2003, and showed an improvement in 2004 and 2005. The data confirm high PHL in breeds with high prevalence and severity of canine hip dysplasia. The high heritability indicates that the DI could be reduced in the breed if PHL were used as a selection criterion. The early favourable evolution of DI breeding values could be related with the increase of voluntary radiographic hip screening in the last years, and the subsequent introduction of hip quality as a breeding criterion.