Mm In Dogs Research Articles

Comparison of radiographic methods for detecting radiolucent uroliths in dogs.

The purpose of this study was to evaluate and compare positive cystography techniques at 5%, 10%, and 20%, as well as three different double-contrast protocols for detecting radiolucent uroliths with a diameter of less than 3.0 mm in dogs. Six cadavers were used, one was selected at random to represent the negative control, and the others were submitted to urolith implantation in the bladder by urethral catheter. Three radiology professionals blindly accessed ventrodorsal and -lateral projections of each test. Contrast at 20% showed greater diagnostic sensitivity, but with greater difficulty identifying the number and size of the uroliths. Consequently, double-contrast techniques are better and should be used for diagnostic and therapeutic planning. Sensitivity and specificity tests demonstrated that positive 5% cystography and different concentrations of double contrast obtained better results in terms of sensitivity and specificity. However, due to the presence of a greater amount of artifacts in the 5% cystography, it is suggested that double contrast is used for this purpose, especially with the removal of contrast excess (protocol 2).

Minimal Invasive Fluoroscopic Percutaneous Lateral Stabilization of Thoracolumbar Spinal Fractures and Luxations Using Unilateral Uniplanar External Skeletal Fixators in Dogs and Cats.

The aim of this study was to describe minimally invasive spinal stabilization using a unilateral uniplanar external skeletal fixator (ESF, type 1a) with polymethylmethacrylate, and to review short- and long-term outcomes and complications in a clinical case series. Medical records from animals affected by spinal fracture luxation were reviewed. The data included breed, age, gender, body weight, aetiology, preoperative and postoperative neurological state, radiographic findings, surgical treatment, pin size, number of pins and stabilized vertebrae, intra- and postoperative complications and neurological state at re-examinations. Thirty-two animals were identified; three were treated conservatively, 19 surgically and 10 were euthanatized. In eight dogs and six cats, the injured spinal column was treated with a laterally applied percutaneous type 1a ESF under fluoroscopic guidance. Positive profile end-threaded pins inserted were from 1.6/1.9 to 3.5/4.3 mm in dogs and 1.6/1.9 to 2/2.3 mm in cats and were placed into two to five vertebral bodies. At the re-examinations, the neurological status had improved in 12 animals, deteriorated in one, and was unchanged in another one. In eight cases, no complications were detected. The most common complications included erythema, exudation and pin loosening. The present work shows that type 1a ESF can be successfully and minimally invasively applied to fractures and luxations of the spine in dogs and cats with minimal major complications.

The expected frequency and amount of free peritoneal fluid estimated using the abdominal FAST-applied abdominal fluid scores in healthy adult and juvenile dogs.

To estimate the frequency and amount of free peritoneal fluid in juvenile and adult dogs using the abdominal focused assessment with sonography for trauma (AFAST) abdominal fluid scoring system. Prospective case series. Healthy, privately owned juvenile and adult dogs. Dogs undergoing routine surgical sterilization were evaluated at induction with AFAST and assigned measurements and fluid scores. A surgeon scored the degree of peritoneal fluid found during ovariohysterectomy. Ninety-two dogs were enrolled (46 juveniles and 46 adults). Ninety-three percent and 52% were AFAST positive for peritoneal fluid, respectively. The AFAST-positive view frequency for right lateral recumbency in juveniles was diaphragmatico-hepatic (DH) 100%, spleno-renal (SR) 20%, cysto-colic (CC) 40%, and hepato-renal (HR) 20% versus adults, DH 60%, SR 20%, CC 0%, and HR 0%, respectively. The AFAST-positive view frequency for left lateral recumbency was DH 93%, SR 44%, CC 24%, and HR 12% in juveniles, and DH 50%, SR 3%, CC 3%, and HR 10% in adults. Overall abdominal fluid scores (AFS) in juvenilles were 0 (n=3), 1 (n=14), 2 (n=22), 3 (n=6), and 4 (n=1); and in adults, scores were 0 (n=22), 1 (n=18), 2 (n=6), and 3 and 4 (n=0). The AFS differed between adults and juveniles (P<0.001). Most dogs had maximum fluid dimensions≤3×3mm and width of fluid stripes≤3mm. The AFS was positively correlated to fluid amount observed during ovariohysterectomy with fair agreement (kappa=0.233, P=0.012). This study establishes the frequency and amount of free peritoneal fluid in healthy juvenile and adult dogs during AFAST. Maximum fluid pocket dimensions of≤3×3mm and fluid stripe widths of≤3mm in dogs with AFS 1 and 2 may be normal. The DH view was most frequently positive.

Animal model considerations to evaluate prosthetic tricuspid valve implants

AimsDetermining tricuspid valve comparative anatomy and appropriate animal models for preclinical evaluation of prosthetic tricuspid valve implants. Methods and resultsWe described and measured 81 heart specimens: 12 humans, 22 dogs, 21 sheep and 26 pigs. Tricuspid annulus circumference varied in humans from 109 to 149 mm, in pigs from 85 to 140 mm, and were ≤125 mm in dogs and sheep. Tricuspid leaflet demarcation in dogs is similar to humans, while in pigs and sheep we observed three distinct leaflets. In humans, sheep and pigs, papillary muscle positions are similar. In dogs they are all based on the septum. A moderator band was observed in all species, but was of consistent thickness only in sheep. ConclusionsSheep and pigs are relevant animal models for evaluating prosthetic tricuspid valve implants. Seventy to 90 kg pigs have a tricuspid annulus size comparable to that in a dilated human heart, but due to possible fast growth leading to sizing incompatibilities, this represents a model for short-term study. Sheep are more stable in size for long term study, however, their tricuspid annulus size is the most similar to that in a healthy, non-dilated human heart. Dogs are not a suitable model due to their significantly different sub-valvular anatomy and smaller size.

Vertical head and pelvic movement symmetry at the trot in dogs with induced supporting limb lameness

Compensatory limb loading has been studied in lame dogs; however, little is known about how these compensations relate to motion of the head and pelvis, assessment of which is an important component of lameness examinations. The aim of this study was to describe the patterns of vertical head and pelvic motion symmetry at the trot in dogs with induced supporting limb lameness in the forelimbs or hind limbs. Ten sound dogs were trotted on a treadmill before and after temporary induction of moderate lameness (grade 2/5) in each limb. Reflective markers were located on the head, pelvis and right forelimb, and kinematic data were captured with a motion capture system. Upper body symmetry parameters were calculated, including differences in the highest (HDmax) and in the lowest (HDmin) positions of the head, and in the highest (PDmax) and in the lowest (PDmin) positions of the mid-pelvis, with a value of zero indicating symmetry. The head was lowered more during the sound limb stance phase and lowered less during the lame limb stance phase in supporting forelimb lameness (HDmin: 4.6mm in dogs when sound, −18.3mm when left limb lameness was induced and 20.5mm when right limb lameness was induced). The mid-pelvis was lowered more during the sound limb stance phase and lowered and lifted less during the lame limb stance phase in supporting hind limb lameness (PDmin: 1mm in dogs when sound, −10.1mm in left limb lameness and 8.4mm in right limb lameness). The hip of the lame side, measured at the level of the greater trochanter, had an increased downwards displacement during the lame limb swing phase (−21mm in left hind limb lameness, P=0.005; 23.4mm in right hind limb lameness, P=0.007). Asymmetry in the lowering of the head or mid-pelvis is a more sensitive indicator of supporting forelimb and hind limb lameness, respectively, than asymmetry in the raising of the head. Increased displacement of the hip (‘hip drop’ of the lame side during its swing phase) is a good indicator of hind limb lameness in dogs.

Proposed expansion margins for planning organ at risk volume for lenses during radiation therapy of the nasal cavity in dogs and cats.

Radiation therapy protocols for the feline or canine nasal cavity can damage epithelial cells of the posterior pole of the lens and lead to the development of cataracts. Aims of this retrospective, descriptive study were to calculate movements of the lens during radiation therapy of the nasal cavity in a sample of cats and dogs, and to propose species-specific expansion margins for planning organ at risk volume (PRV) to minimize radiation doses to the lens. All included patients were immobilized with an indexed bite block and positioned in a vacuum positioning cushion for head irradiation. On-board cone beam CT (CBCT) imaging was used for patient alignment. Both ocular lenses were contoured on the therapeutic CBCTs. Coregistration (fusion) between the planning CT and CBCTs was used to measure the movements of the lens. Two measurements were made: the differences between the centroid point of each lens as well as the displacement of the coregistrations. A total of 496 different observations were recorded from 14 cats and 52 dogs. Using the displacement results, we calculated how often the lens would be within the lens-PRV contour. We proposed that an optimal expansion margin from the lens volume of 2 mm in cats and 3 mm in dogs may be necessary in generating PRV expansion for the lens. From our results, we expect the lens would therefore be within these proposed PRV expansions in 92% of the feline measurements and 95% of the canine measurements.

Anatomical and ultrasonographic study of the femoral nerve within the iliopsoas muscle in beagle dogs and cats

ObjectivesAn ultrasound (US)-guided ventral suprainguinal approach to block the femoral nerve (FN) within the iliopsoas muscle (IPM) has recently been described in dogs. The goal of the present study was to provide the operator with additional information to locate the FN within the IPM in dogs and cats using US. Study designThe study was carried out in three phases: a dissection of the FN (phase 1); an in vivoUS-assisted nerve study (phase 2), and an anatomical cross-sectional study (phase 3). AnimalsNine healthy adult beagle dogs and nine healthy adult cats. MethodsDissections were performed to investigate the anatomical characteristics of the FN and its related structures in one dog and one cat. Ultrasound scans of the left and right FN were performed in eight dogs and eight cats. The FN diameter and the distance between the FN and the external iliac artery (EIA) in US images and in anatomical cryosections were measured. ResultsThe median FN diameter did not differ significantly between cats and dogs (1.1 mm versus 1.0 mm) or between the two techniques (US versus anatomical cross-sectional study) (1.1 mm versus 1.1 mm in dogs; 1.0 mm versus 1.1 mm in cats). The US and anatomical measurements of the median distances between the FN and EIA differed significantly between dogs and cats (8.2 mm versus 5.8 mm by US; 5.7 mm versus 4.8 mm in the anatomical study). Conclusions and clinical relevanceThe distance between the EIA and FN is reproducible in beagle dogs and cats and can be used in locating the FN within the IPM.

INTER- AND INTRAFRACTION MOTION FOR STEREOTACTIC RADIOSURGERY IN DOGS AND CATS USING A MODIFIED BRAINLAB FRAMELESS STEREOTACTIC MASK SYSTEM.

Precise and accurate patient positioning is necessary when doing stereotactic radiosurgery (SRS) to ensure adequate dosing to the tumor and sparing of normal tissues. This prospective cross-sectional study aimed to assess feasibility of a commercially available modified frameless SRS positioning system for use in veterinary radiotherapy patients with brain tumors. Fifty-one dogs and 12 cats were enrolled. Baseline and verification CT images were acquired. The verification CT images from 32 dogs and five cats had sufficient images for fusion to baseline CT images. A rigid box-based fusion was performed to determine interfraction motion. Forty-eight dogs and 11 cats were assessed for intrafraction motion by cine CT. Seventy percent of dogs and 60% of cats had interfraction 3D vector translational shifts >1 mm, with mean values of 1.9 mm in dogs, and 1.8 mm in cats. In dogs muscle wasting was weakly correlated with translational shifts. The maximum angular interfraction motion observed was 6.3° (roll), 3.5° (pitch), and 3.3° (yaw). There was no correlation between angular interfraction motion and weight, brachycephaly, or muscle wasting. Fifty-seven percent of dogs and 50% of cats had respiration-related intrafraction motion. Of these, 4.5% of dogs and 10% of cats had intrafraction motion >1 mm. This study demonstrates the modified Brainlab system is feasible for SRS in dogs and cats. The smaller cranial size and difference in anatomy increases setup uncertainty in some animals beyond limits usually accepted in SRS. Image-guided positioning is recommended to achieve clinically acceptable setup accuracy (<1 mm) for SRS.

Comparison of atrial artery distribution among dogs, sheep and pigs by coronary vascular corrosion casting

ObjectiveWe compared the similarity and difference of atrial artery distribution in dogs, sheep and pigs, to investigate the suitability of sheep and dogs, rather than pigs, as an animal model...

The effect of the monoamine oxidase inhibitor isocarboxazid on the canine metabolism of the cell-differentiating agent hexamethylene bisacetamide

The acute toxicities of the cellular differentiating agent hexamethylene bisacetamide (HMBA) in humans and animals include CNS toxicity (agitation, somnolence, seizures, hallucinations) and an anion-gap metabolic acidosis. N-Acetyl-1,6-diaminohexane (NADAH), the first metabolite of HMBA, is as active as the parent compound in causing differentiation of leukemic cells in vitro, whereas 6-acetamidohexanoic acid (6AcHA), which is formed by the oxidation of NADAH in the presence of monoamine oxidase (MAO) and aldehyde dehydrogenase, is inactive. To test whether the inhibition of MAO blocks the production of an inactive and possibly toxic HMBA metabolite (6AcHA) or increases the amount of active compounds (HMBA + NADAH) in vivo, we investigated the effect of the MAO inhibitor isocarboxazid on the metabolism and toxicity of HMBA in beagle dogs. Two groups of dogs, composed of one male and one female dog per group, were used in the study. One group received isocarboxazid (3.3 mg/kg p.o. q8h x 9) beginning at 24 h before the initiation of a 48-h i.v. infusion of HMBA (40 mg kg-1 h-1), whereas the other received placebo in an identical fashion prior to the start of an identical HMBA infusion. The mean plasma steady-state concentration (css) of HMBA was 0.91 mM in dogs given HMBA and isocarboxazid as opposed to 0.78 mM in those given HMBA and placebo. As measured spectrophotometrically, plasma MAO activity was inhibited by 86% +/- 3% in dogs receiving isocarboxazid. Gas chromatography/mass spectrometry detected 6AcHA in the plasma of animals that were given placebo but not in the plasma of dogs that received isocarboxazid. Gas chromatographic analysis of urine samples revealed that the total amount of 6AcHA and of NADAH excreted in urine was 8 times less and 3 times greater, respectively, in isocarboxazid-treated dogs than in animals that received HMBA and placebo. One dog was excitable after the initial two doses of isocarboxazid and developed seizures at the end of the HMBA infusion. Another dog was agitated during treatment with HMBA and isocarboxazid. No CNS toxicity occurred in animals that were treated with HMBA and placebo. We conclude that isocarboxazid inhibits the production of 6AcHA in vivo, thus supporting the involvement of MAO in HMBA metabolism. Because the combination of HMBA and isocarboxazid produces CNS toxicity, 6AcHA is probably not the neurotoxic agent in dogs.

Effect of furosemide on cerebrospinal fluid composition

Electrolyte composition of the cerebral spinal fluid (CSF) is important in central respiratory drive. The relationship between [Cl −] and [HCO 3 −] is of particular interest in maintenance of electrolyte balance. Therefore, the effect of furosemide, an inhibitor of sodium-coupled chloride transport, on CSF electrolyte homeostasis was studied under conditions of normocapnia and hypercapnia in anesthetized dogs. The drug was given intravenously (IV) or in the lateral cerebral ventricles (CV). With normocapnia, there was no change in CSF or arterial P CO 2 , pH, [K +], [Cl −], or [HCO 3 −], while CSF [Na +] decreased 1.7 mM in dogs receiving IV furosemide. With 5% CO 2 breathing and IV furosemide, CSF P CO 2 , pH, [K +], [Cl −], and [HCO 3 −] changed as has been reported for 5% CO 2 breathing alone. 5% CO 2 and CV furosemide, however, led to a greater reduction in CSF [Cl −] and no change in CSF [HCO 3 −]. Thus CV furosemide alters the CSF [Cl −] and [HCO 3 −] in hypercapnia, suggesting that sodium-coupled chloride transport plays a role in regulation of CSF acid-base homeostasis.

Changes in renal metabolite profile and ammoniagenesis during acute and chronic metabolic acidosis in dog and rat

Acute metabolic acidosis was induced by an i.v. administration of hydrochloric acid to dogs and rats to decrease the plasma bicarbonate concentration from 22 to 12 mM in dogs and from 26 to 10 mM in rats. Chronic metabolic acidosis was also induced in dogs by ammonium chloride feeding for 5 days. Rats also were given ammonium chloride for 24 hours. The renal metabolite profile was determined on the freeze-clamped renal tissue before and after 100 min (dogs) or 30 to 240 min (rats) of acsute acidosis. Measurements on chronically acidotic dogs and rats with 24-hour acidosis were obtained also for comparison with acute acidosis. In both species, kidney glutamine, glutamate, and alpha-ketokglutarate concentrations decreased drastically following induction of acute or chronic acidosis, In the dog, or in the rat during the first 2 hours of acidosis, malate concentration was unchanged. Malate concentration fell significantly in the rat kidney only after 2 hours of acidosis without change in phosphoenolpyruvate (PEP) concentration. In chronically acidotic dogs, malate and oxaloacetate rose fivefold with no change in PEP concentration. Phosphoenolpyruvate carboxykinase (PEPCK) activity was not stimulated by chronic metabolic acidosis in the dog in contrast to the rat. Acute acidosis by hydrochloric acid increased net renal glutamine extraction in the rat but not in the dog. These data suggest that an increased metabolic flux occurs between alpha-ketoglutarate and malate in both rat and dog kidney during acute metabolic acidosis. In the rat, however, after 2 hours, PEPCK activation modifies the kidney metabolite profile. Intrarenal glutamine transport seems to be a rate-limiting factor for adaptation to acute acidosis in the dog but not in the rat kidney.

In vivo roentgenographic examination of parasympathetic innervation of small airways. Use of powdered tantalum and a fine focal spot x-ray tube.

A study was made roentgenographically of the peripheral airways in vivo by using powdered tantalum as contrast medium, a small focal spot x-ray tube (0.06 mm side dimensions), and primary radiographic magnification. Despite the limited output of the x-ray tube (2.5 ma), we obtained satisfactory bronchograms with short exposures at 120 kVp. This technique enabled us to study the effect of vagal stimulation on the airways in vagotomized cats and dogs. Vagal stimulation resulted in slight constriction in the trachea and large bronchi and maximum constriction in airways whose resting diameters were 1–5 mm in dogs and 0.8–2.0 mm in cats. Constriction was diminished in airways with diameters less than 0.8–1.0 mm and was insignificant in airways less than 0.5 mm in diameter. In a comparative study with x-ray tubes of different focal spot side dimensions, we established that the tube with a 0.06 mm focal spot increased the ability of observers to detect changes in airway diameter.

Cross Transfusion as a Means of Determining Toxic Factors in Blood from Burned Animals

In our experiments studying the effect of transfusion of blood from a burned animal (dog) to a normal animal we resorted to a method of cross transfusion which obtained blood from the vena cava (draining the burned area), and cross transfused large quantities (several hundred cc) to and from the normal and burned animal. The average drop in blood pressure of dogs receiving blood from normal dogs was 19 mm of mercury, compared to a drop of 42 mm in dogs receiving blood from burned animals in the same quantity and same speed of injection. The mortality rate in 30 dogs receiving blood from the vena cava of normal animals was 16.6% compared to a rate of 27.7% in 18 dogs receiving blood from the vena cavaof animals burned on the lower extremities and distal torso.