Search

Intraneural perineurioma is an exceptionally rare neoplasm in animals. This case study comprises a series of three cases and a brief literature review focusing on canine intraneural perineurioma. The pathological and immunohistochemical findings are documented, revealing that canine intraneural perineurioma frequently a ects adult dogs aged between 3 and 10 years old, with a male predominance. Clinical signs associated with intraneural perineurioma in dogs include spinal pain, lameness, and paresis, resulting from the involvement of spinal nerve roots of the pelvic limbs, brachial plexus, or distal part of the median nerve. Most neoplasms had characteristic pseudo-onion bulb patterns on histopathology. Neoplastic perineurial cells, inmost cases, expressed laminin and claudin-1, and NF200 consistently highlighted the central axon. While the immunohistochemical (IHC) profile of intraneural perineurioma in veterinary medicine remains incompletely characterized, the available IHC data from all reported cases suggest that a combination of laminin and claudin- 1 immunomarkers, along with distinctive histological features, can assist in establishing a definitive diagnosis of intraneural perineurioma. [ABSTRACT FROM AUTHOR]

Systemic hypertension (SH) in cats may occur secondary to renal disease, hyperthyroidism, or idiopathic causes. Asymmetric dilation of the sinuses of Valsalva has been recognized in people with systemic hypertension as target organ damage (TOD). Aortic knob formation (lateral bowing of the aortic arch to proximal descending aorta on the posteroanterior/anteroposterior radiographic projection) is recognized as TOD in people due to SH. None of these changes have been reported in feline patients. The first objective of this retrospective case‐controlled study was to compare echocardiographic changes in the aorta of 76 cats with systemic hypertension (SH) to those seen in 76 cats with normal blood pressure (NBP). Our second objective was to have blinded reviewers assess heart size and aortic shape and size from available thoracic radiographs of 49/76 cats with SH and 46/76 cats with NBP. A two‐way unpaired t‐test with significance set at alpha = 0.01 was used to evaluate aortic echocardiographic parameters. The mean of the aortic diameter and length of each aortic cusp was significantly larger in cats with SH than in cats with NBP. The aortic cusps were considered altered in size in 62 of 76 cats with SH, 12/62 ≥ with 0.5 mm, and 50/62 ≥ 1.0 mm. No significant difference in the vertebral heart score (VHS) was noted between groups. The aortic knob to lateral margin of the trachea in cats with SH had an area under the curve (AUC) of 0.74 (95% CI:0.61‐0.87) with best cutoff of 1.12 cm with sensitivity of 81% and specificity of 69%. [ABSTRACT FROM AUTHOR]

Mitral regurgitation (MR) is associated with increased neuronal release of norepinephrine (NE) and epinephrine (EP) into myocardial interstitial fluid (ISF) that may be necessary in sustaining left ventricular (LV) function via activation of cardiomyocyte [beta]-adrenergic receptors (ARs). However, activation of neuronal [beta]-ARs on cardiac neurons may lead to further catecholamine release, with an attendant risk of functional deterioration. We hypothesize that a beneficial effect of [beta]-AR blockade may therefore mitigate excessive catecholamine release from cardiac adrenergic neurons in dogs with MR. We measured the effects of chronic [beta]-receptor blockade ([beta]-RB) on ISF NE and EP release using in vivo microdialysis in open-chest anesthetized dogs after 4 wk of MR with or without extended release of metoprolol succinate (100 mg/day) as well as in control dogs. Fractional shortening increased by 30% in both MR and MR + [beta]-RB dogs after 4 wk of MR. In MR + [beta]-RB dogs, stellate-stimulated heart rate change was attenuated compared with control and MR dogs, whereas peak change of LV pressure over time (+dP/dt) increased equally in all groups. Stellate-stimulated ISF NE increased five-fold over baseline in MR versus twofold in control dogs ( interstitial fluid; epinephrine

Chronically sustained systemic hypertension in dogs can damage the kidneys, eye, brain, heart, and vessels. In human medicine, systemic hypertension has been implicated as the most common risk factor for aorta dilation, which can progress to an aneurysm. Abdominal ultrasound has been commonly used to monitor the size of the abdominal aorta in people with systemic hypertension. In this retrospective cross‐sectional abdominal ultrasound study, evaluation of the size of the abdominal aorta relative to the caudal vena cava was performed in 18 control dogs and 128 dogs with confirmed systemic hypertension. Preexisting conditions contributing to systemic hypertension in these dogs were renal disease, hyperadrenocorticism, diabetes mellitus, adrenal tumors, and previous administration of phenylpropanolamine or palladia. The abdominal aorta and caudal vena cava were assessed from longitudinal images cranial to the trifurcation with measurements made from outer border to outer border of the walls, being careful not to compress the caudal vena cava that would alter its size. Our hypothesis was the ratio of the diameter of the abdominal aorta to caudal vena cava would be higher in dogs with systemic hypertension compared to dogs with normal blood pressure. The mean abdominal aorta‐caudal vena cava ratio was 1.028 in control dogs with a normal blood pressure and 1.515 in dogs with systemic hypertension. In dogs with confirmed systemic hypertension, the abdominal aorta was dilated compared to the caudal vena cava in the caudal abdomen. An increase in the abdominal aorta‐caudal vena cava ratio in a dog should raise suspicion for the presence of systemic hypertension and prompt evaluation of blood pressure. [ABSTRACT FROM AUTHOR]

1. Previous studies have demonstrated progressive ventricular hypertrophy, dilatation and contractile depression in response to chronic volume overload. Whether this decompensation was related to intrinsic myocyte dysfunction was not clear. The present study evaluated ventricular myocyte function at critical times during the progression of ventricular remodelling induced by volume overload. 2. Chronic volume overload was induced with an infrarenal aortocaval fistula in rats. Myocyte contraction and intracellular Ca2+ concentrations ([Ca2+]i) were evaluated using a fura-2 fluorescence and edge detection system. Protein levels of sarcoplasmic reticulum (SR) Ca2+ transporters were determined by western blots. Progressive ventricular dilatation developed following creation of the fistula. Although myocyte function in 5 week fistula rats was comparable to that of the control group, myocytes from rats 10 weeks post-fistula demonstrated significant depression of cell shortening and peak [Ca2+]i. Application of isoproterenol (0.1 µmol/L) was not able to compensate for the functional deficiency in myocytes from 10 week fistula rats. Caffeine (10 mmol/L) induced SR Ca2+ release, as well as protein expression of SR Ca2+-ATPase, and ryanodine receptors were reduced in myocytes obtained from the same group of 10 week fistula rats. 3. These data indicate that the transition to heart failure secondary to chronic volume overload is related to depressed myocyte contractility secondary to altered intracellular Ca2+ homeostasis. [ABSTRACT FROM AUTHOR]

Mitral regurgitation (MR) is associated with increased neuronal release of norepinephrine (NE) and epinephrine (EP) into myocardial interstitial fluid (ISF) that may be necessary in sustaining left ventricular (LV) function via activation of cardiomyocyte β-adrenergic receptors (ARs). However, activation of neuronal β-ARs on cardiac neurons may lead to further catecholamine release, with an attendant risk of functional deterioration. We hypothesize that a beneficial effect of 13-AR blockade may therefore mitigate excessive catecholamine release from cardiac adrenergic neurons in dogs with MR. We measured the effects of chronic β-receptor blockade (β-RB) on ISF NE and EP release using in vivo microdialysis in open-chest anesthetized dogs after 4 wk of MR with or without extended release of metoprolol succinate (100 rag/day) as well as in control dogs. Fractional shortening increased by 30% in both MR and MR + β-RB dogs after 4 wk of MR. In MR + β-RB dogs, stellate-stimulated heart rate change was attenuated compared with control and MR dogs, whereas peak change of LV pressure over time (+dP/dt) increased equally in all groups. Stellate-stimulated ISF NE increased fivefold over baseline in MR versus twofold in control dogs (<0.05), but the NE release was significantly attenuated in MR + β-RB dogs. In contrast, stellate-stimulated increases in ISF EP did not differ in control, MR, and MR + β-RB dogs. This study demonstrates that β-RB attenuates ISF NE release from cardiac neurons and that the LV functional response to MR is not dependent on an excess increase in ISF NE. Thus β1-RB may exert a beneficial effect by attenuating untoward effects of excessive sympathetic efferent neural NE release while sustaining early LV functional adaptation to MR. [ABSTRACT FROM AUTHOR]

Alfaxalone is a neuroactive steroid that modulates the GABA A receptor, which has shown recent widespread use as a sedative and anesthetic agent in cats, especially in patients being screened for cardiovascular disease. This prospective, partially blinded, randomized experimental study aimed to determine if sedation with alfaxalone would alter the appearance of the cardiac silhouette or pulmonary vasculature on thoracic radiographs or echocardiographic indices of cardiac or pulmonary vascular size. Eleven apparently healthy adult cats were recruited from a research colony. Four-view thoracic radiographs and an echocardiogram were performed at baseline and following a 5 mg/kg intramuscular dose of alfaxalone. Vertebral heart score (VHS) and cranial and caudal lobar pulmonary vascular measurements were obtained at both time points by two independent blinded observers, and these were analyzed using two-way ANOVA. The nonblinded echocardiographer obtained echocardiographic measurements at both time points, which were analyzed using a paired t-test or Wilcoxon signed rank test. No significant differences were identified in VHS measurements or echocardiographic parameters between baseline and sedated cats. In healthy cats, alfaxalone does not appear to significantly affect the cardiovascular structures evaluated via thoracic radiography or echocardiography., (© 2024 American College of Veterinary Radiology.)

Elastography is a sonographic modality that measures tissue stiffness, a mechanical property of tissues, and a biomarker for disease. Canine musculoskeletal application to the patellar tendon has been limited to semiqualitative strain elastography. This prospective study aimed to quantitatively evaluate patellar tendon stiffness using shear-wave elastography with a color map superimposed over the tendon, a propagation map for quality control, and measurements at specific regions of interest in 16 clinically normal sedated dogs weighing 25 kg or greater. Tendon stiffness using shear-wave elastography (SWE) was assessed at different stifle angles and in three regions to determine if angle and location affected stiffness. All dogs were screened with general and orthopedic exams, lateral stifle radiographs, and patellar tendon 2D ultrasound. Shear-wave elastography was performed from a long axis at various stifle angles at the proximal, middle, and distal tendon segments. Quality diagnostic SWE results varied significantly with stifle angle, and 150° of extension was the only angle found to be clinically useful based on the ease of obtaining measurable results and a quality control propagation wave. Patellar tendons were primarily stiff with a red color elastogram. The proximal and middle segments, measured at various angles, had a mean SWE velocity of 7.32 ± 0.90 m/s. Tendon stiffness did not differ along tendon length when measured in greater extension. However, stiffness decreased in the middle segment of the tendon at 150° when compared with 120°. This study establishes a quantitative baseline of normal patellar tendon stiffness to compare with pathologic states., (© 2024 American College of Veterinary Radiology.)

Background: This study tested the hypothesis that beta1-adrenoreceptor blockade modulates the angiotensin II (Ang II)-evoked neural release of norepinephrine (NE) and epinephrine (Epi) into the cardiac interstitial fluid (ISF) space in experimentally induced mitral regurgitation (MR) in the dog., Methods and Results: Normal dogs (n=8) were compared with dogs with MR of 2 (n=8) and 4 (n=6) weeks' duration and with dogs with MR treated with beta1-receptor blockade (RB; extended-release metoprolol succinate, 100 mg QD; MR+beta1-RB) that was started 24 hours after MR induction for 2 (n=6) and 4 weeks (n=8). Left ventricular end-diastolic dimension increased 20% as plasma Ang II levels increased >5-fold in both MR and MR+beta1-RB dogs at 2 and 4 weeks. Ang II infusion into the left atrium produced increases in ISF NE and Epi in normal dogs, which were further increased in 2- and 4-week MR dogs but were restored to normal in 4-week MR+beta1-RB dogs. Ang II infusion produced 4-fold increases in circulating NE and Epi in 2- and 4-week MR dogs that returned to normal in 4-week+beta1-RB dogs. Left ventricular angiotensin-converting enzyme activity and ISF Ang II were increased in 4-week MR dogs but were decreased in 4-week MR+beta1-RB dogs., Conclusions: beta1-RB decreases renin-angiotensin system sympathostimulation and activation by attenuating the Ang II-mediated NE and Epi release into the cardiac ISF and circulation and by decreasing left ventricular angiotensin-converting enzyme expression in the early phases of volume overload.