Anatomy of the brain of capybara (Hydrochoerus hydrochaeris) using magnetic resonance imaging.

Capybara is considered the largest living rodent and is widespread distributed in the South America and in the Brazilian territory. The purpose of this study was to provide the anatomical description of the brain in the capybara (Hydrochoerus hydrochaeris) using magnetic resonance imaging (MRI). Brains of ten normal capybaras were imaged and sectioned in the anatomical studies. MRI was acquired on 0.25 Tesla equipment, promoting good-quality images capable to identify and classify the main anatomical structures of clinical interest. MRI reference images were validated by comparing them with gross anatomical sections. The capybara sulci and gyri were named for its similar location and orientation to those described in the previous descriptions in the capybara and in the domestic dog. Capybaras presented prominent cerebral sulcus and gyrus in relation to other caviomorph rodents, but in reduced number when compared to domestic animals and other wild mammals such as elephants and giraffes. The findings of this study indicate that the shape of the capybara brain is remarkably similar to that of the caviomorph rodents with a higher neocortilization. The capybara rhinencephalon was well-developed implying a good sense of smell. Due to this development of the rhinencephalon, we can suggest that capybara brain is a macrosmatic brain. The MRI and gross anatomical sections of capybara brain may help veterinary researchers and clinicians increase the accuracy of brain MRI scans interpretation in these animals.

Morphometric and morphologic parameters of the heart in healthy Alouatta guariba clamitans (Cabrera, 1940).

BACKGROUND: This study aimed at assessing the heart function of one neotropical primate (Alouatta guariba clamitans) kept in captivity using radiography, electrocardiogram (ECG) and Doppler echocardiography. METHODS: Ten adult healthy howler monkeys (A. g. clamitans) were evaluated under general anaesthesia. Vertebral Heart Scores (VHS) were obtained from radiographic studies. Ejection fraction, shortening fraction of left ventricle, left atrial/aortic root ratio, ascending aortic diameter, peak velocity of pulmonary, mitral, tricuspid and aortic blood flow and other values were measured by Doppler echocardiography. Heart rate, mean electrical axis of QRS complex, P, Q, R, S, T amplitude, P, PR interval, QRS, QT interval duration and ST segment unbalancing were measured by ECG. RESULTS AND CONCLUSIONS: Exam techniques were akin the ones used in humans. Doppler echocardiographic, radiographic, electrocardiographic and clinical parameters for howler monkey were described and correlated. The results have shown profiles of cardiovascular function and structure of A. g. clamitans.

Hypotension aggravated by dopamine in a dog under isoflurane anesthesia

Background: Hypotension (MAP < 60 mmHg) is the most common complication in anesthetic practice and has been identified in 38% of canine patients undergoing general anesthesia for variety of procedures. Normalization of arterial pressure can usually be achieved by decreases in inhalant anesthetic concentrations, fluid administration, and use of inotropes/ vasopressors in healthy animals (ASA I) or animals with mild systemic disease (ASA anesthetic risk II). The present report shows an ASA II dog with severe hypotensive crisis [mean arterial pressure (MAP) < 50 mmHg] during general anesthesia, in which the procedure was aborted because hypotension was aggravated by dopamine.Case: A 7-year-old male Bull Terrier was anesthetized for magnetic resonance imaging (MRI) of a tumor in the face. After intramuscular acepromazine (0.01 mg/kg) and meperidine (3 mg/kg), anesthesia was induced with intravenous (IV) ketamine (1 mg/kg) and propofol (2.3 mg/kg) and maintained with isoflurane in oxygen. Ten min after induction of anesthesia MAP was 45 mmHg, while end-tidal isoflurane (ETISO) concentration was 0.5%. End-tidal isoflurane was decreased to 0.3% and an IV bolus of Lactated Ringers was initiated (15 mL/kg over 10 min), followed by two ephedrine boluses (0.1 mg/kg, IV) administered 5 min apart. MAP remained low (< 50 mmHg) and dopamine constant rate infusion (CRI) was initiated (7.5 μg/kg/min). Ten minutes after dopamine CRI was commenced, MAP was further decreased to 25-22 mmHg. Dopamine CRI was increased to 10 μg/kg/min, but MAP remained < 25 mmHg. Infusion drugs and isoflurane anesthesia were stopped. After the animal was extubated MAP returned 60-70 mmHg.Discussion: Among the drugs used, isoflurane is known for decreasing blood pressure in a dose-related manner because of its vasodilating properties.[...](AU)

Hypotension aggravated by dopamine in a dog under isoflurane anesthesia

Background: Hypotension (MAP < 60 mmHg) is the most common complication in anesthetic practice and has been identified in 38% of canine patients undergoing general anesthesia for variety of procedures. Normalization of arterial pressure can usually be achieved by decreases in inhalant anesthetic concentrations, fluid administration, and use of inotropes/ vasopressors in healthy animals (ASA I) or animals with mild systemic disease (ASA anesthetic risk II). The present report shows an ASA II dog with severe hypotensive crisis [mean arterial pressure (MAP) < 50 mmHg] during general anesthesia, in which the procedure was aborted because hypotension was aggravated by dopamine.Case: A 7-year-old male Bull Terrier was anesthetized for magnetic resonance imaging (MRI) of a tumor in the face. After intramuscular acepromazine (0.01 mg/kg) and meperidine (3 mg/kg), anesthesia was induced with intravenous (IV) ketamine (1 mg/kg) and propofol (2.3 mg/kg) and maintained with isoflurane in oxygen. Ten min after induction of anesthesia MAP was 45 mmHg, while end-tidal isoflurane (ETISO) concentration was 0.5%. End-tidal isoflurane was decreased to 0.3% and an IV bolus of Lactated Ringer’s was initiated (15 mL/kg over 10 min), followed by two ephedrine boluses (0.1 mg/kg, IV) administered 5 min apart. MAP remained low (< 50 mmHg) and dopamine constant rate infusion (CRI) was initiated (7.5 μg/kg/min). Ten minutes after dopamine CRI was commenced, MAP was further decreased to 25-22 mmHg. Dopamine CRI was increased to 10 μg/kg/min, but MAP remained < 25 mmHg. Infusion drugs and isoflurane anesthesia were stopped. After the animal was extubated MAP returned 60-70 mmHg.Discussion: Among the drugs used, isoflurane is known for decreasing blood pressure in a dose-related manner because of its vasodilating properties.[...]

Pacemaker implant in a dog with sick sinus syndrome

Background: Sick sinus syndrome is characterized by the presence of arrhythmias, including persistent sinus bradycardia, sinus arrest and paroxysmal atrial tachyarrhythmia. It commonly occurs in elderly dogs, especially miniature schnauzers; however, it is also detected in dachshunds and pugs. Reports of clinical signs by animal owners are not always clear and precise, which may result in erroneous interpretations by veterinarians; consequently, the use of inappropriate therapies. The present work aims to describe clinical aspects and findings from tests related to sick sinus syndrome (SSS) and presents the case of a female schnauzer with SSS. Case: A 10-year-old female dog (schnauzer, 8.6 kg) attended the Veterinary Hospital of the FMVZ-UNESP - Botucatu. The owner mentioned convulsive episodes, but a thorough medical history and patient assessment revealed that the dog exhibited episodes of syncope. During the physical examination, cardiac auscultation revealed the heart rate to be 56 beats per minute (bpm), and there was a presence of pauses. Also during cardiac auscultation, a holosystolic heart murmur was verified, with a focus on the mitral and tricuspid valves. The electrocardiogram showed the presence of sinus arrest with escape rhythms, pauses of 10 s and the presence of bradycardia-tachycardia syndrome. A Holter monitor was used to establish the diagnosis of SSS. The patient presented with significant episodes of syncope during outpatient care, and based on the clinical manifestation, drug therapy was initiated. The prescribed medications were aminophylline 20 mg/ kg TID, enalapril maleate 0.5 mg/kg BID, spironolactone 1 mg/kg SID and furosemide 2 mg/kg BID. After the start of treatment, there was a reduction in the frequency of episodes of syncope. Three weeks after diagnosis, a pacemaker device was implanted. Currently, clinical signs are absent. Discussion: Sinus node dysfunction is one of the main reasons for pacemaker implantation. […]

Pacemaker implant in a dog with sick sinus syndrome

Background: Sick sinus syndrome is characterized by the presence of arrhythmias, including persistent sinus bradycardia, sinus arrest and paroxysmal atrial tachyarrhythmia. It commonly occurs in elderly dogs, especially miniature schnauzers; however, it is also detected in dachshunds and pugs. Reports of clinical signs by animal owners are not always clear and precise, which may result in erroneous interpretations by veterinarians; consequently, the use of inappropriate therapies. The present work aims to describe clinical aspects and findings from tests related to sick sinus syndrome (SSS) and presents the case of a female schnauzer with SSS. Case: A 10-year-old female dog (schnauzer, 8.6 kg) attended the Veterinary Hospital of the FMVZ-UNESP - Botucatu. The owner mentioned convulsive episodes, but a thorough medical history and patient assessment revealed that the dog exhibited episodes of syncope. During the physical examination, cardiac auscultation revealed the heart rate to be 56 beats per minute (bpm), and there was a presence of pauses. Also during cardiac auscultation, a holosystolic heart murmur was verified, with a focus on the mitral and tricuspid valves. The electrocardiogram showed the presence of sinus arrest with escape rhythms, pauses of 10 s and the presence of bradycardia-tachycardia syndrome. A Holter monitor was used to establish the diagnosis of SSS. The patient presented with significant episodes of syncope during outpatient care, and based on the clinical manifestation, drug therapy was initiated. The prescribed medications were aminophylline 20 mg/ kg TID, enalapril maleate 0.5 mg/kg BID, spironolactone 1 mg/kg SID and furosemide 2 mg/kg BID. After the start of treatment, there was a reduction in the frequency of episodes of syncope. Three weeks after diagnosis, a pacemaker device was implanted. Currently, clinical signs are absent. Discussion: Sinus node dysfunction is one of the main reasons for pacemaker implantation. […](AU)