The effect of different body positions on the cardiothoracic ratios obtained by chest radiography in Japanese macaques (Macaca fuscata) and rhesus macaques (Macaca mulatta).

BACKGROUND: Although some studies have reported cardiac diseases in macaques, an adequate screening method for cardiac enlargement has not yet been established. This study aimed to evaluate the positioning of macaques for radiographs and establish reference intervals for the cardiothoracic ratio (CTR). MATERIALS AND METHODS: We developed a device for chest radiography in the sitting position and performed chest radiography in 50 Japanese and 48 rhesus macaques to evaluate the CTR and chest cavity size. RESULTS: In Japanese and rhesus macaques, the thorax height was significantly larger, the heart width was significantly smaller, and the mean CTR was significantly smaller in the sitting position than in the prone position. The reference intervals for CTR in the sitting position were 51.6 ± 4.6% and 52.2 ± 5.1% in Japanese and rhesus macaques, respectively. CONCLUSION: Thoracic radiographic images obtained in a sitting position resulted in a smaller CTR and a larger thorax height, which could be useful for detecting pulmonary and cardiac abnormalities.

Evaluation of plasma atrial natriuretic peptide concentration in healthy bottlenose dolphins (Tursiops truncates).

There are currently no standard methods for diagnosing cardiac diseases in dolphins. These diseases may consequently be overlooked and go undiagnosed. The presence and severity of cardiac diseases in humans can be determined using blood tests. Atrial natriuretic peptide (ANP) used in human cardiac examinations has low species specificity. There have already been reports of homology between dolphin and human ANP; however, its potential for clinical application in dolphins has not been tested. This study was conducted to establish a reference for ANP levels in healthy bottlenose dolphins. Healthy bottlenose dolphins (seven females; estimated to be 7-30 years of age) at an aquarium in Japan were sampled. Each animal was tested for ANP at least three times, and the mean value and standard deviation were calculated to be 43.4 ± 19.2 pg/mL. In humans, patients with high plasma ANP levels have a poor prognosis. In veterinary medicine, cutoff values for the diagnosis of mitral regurgitation and heart failure in dogs have been established and used to predict prognosis. The results of the present study may contribute to the health management of bottlenose dolphins, particularly in the early detection and treatment of cardiac diseases.

Pathophysiological and Pedigree Analysis of Left Ventricular Noncompaction in Japanese Macaques (Macaca fuscata).

Left ventricular noncompaction (LVNC) involving genetic mutation is categorized as an unclassified cardiomyopathy, and its diagnostic criteria have not been standardized. This could be because precise animal models of LVNC have not been created in any laboratory animal species. This study aimed to analyze the pathophysiology and familial tendency of LVNC in Japanese macaques. Two Japanese macaques with LVNC, and their parents who were suspected of having cardiac disease, were examined. One macaque with LVNC was examined using chest radiography, echocardiography, cardiac biomarkers, cardiac MRI, and pathologic examination, and the other macaque was examined using chest radiography, echocardiography, and cardiac biomarkers. Their common father and the mother of one of the macaques with LVNC were tested for chest radiography and cardiac biomarkers. Echocardiography revealed a meshwork with trabeculation and deep intertrabecular recesses in all their left ventricular walls. The 2 macaques with LVNC demonstrated a layered appearance of the myocardium, consisting of noncompacted myocardium on the endocardial side and compacted myocardium on the epicardial side, with a noncompacted/compacted ratio of 6.0 and 5.8, respectively. One of the 2 macaques with LVNC (case 1) had elevated levels of troponin I, troponin T, atrial natriuretic peptide, and brain natriuretic peptide. The second macaque with LVNC (case 2) showed blood flow in the intertrabecular recesses on echocardiography. The common father (case 3) of the 2 macaques with LVNC and the mother (case 4) of one of the macaques with LVNC had elevated levels of troponin I and troponin T. In case 1, histopathologic examination revealed fibrous thickening of the endocardium, fibrosis of the myocardial interstitium, myocardial disarray, vacuolar degeneration, anisonucleosis, and necrosis of myocardial cells. This suggests that Japanese macaques could serve as a reliable animal model of human LVNC.

Aquatic environments change the cardiac morphology of dolphins.

Previous studies on dolphin electrocardiograms have shown that they are mainly composed of increased negative waves, similar to ungulates. The electrocardiogram waveform was determined by the distribution of the Purkinje fibers. Based on the waveform of the dolphin electrocardiogram, Hamlin predicted that the Purkinje fibers would be distributed within the ventricular muscle, as in ungulates. The purpose of this study was to confirm the histological distribution of Purkinje fibers in dolphins. In the present study, bottlenose dolphin hearts were observed both grossly and histologically, and the effects of Purkinje fiber distribution and cardiac morphology on electrocardiogram waveforms were examined. This study showed that the Purkinje fibers of dolphins run just below the endocardium, as in humans, dogs, and cats, whose electrocardiograms mainly show positive waves. When the cardiac morphology of dolphins was observed carefully, the right ventricle was found to be extremely dilated compared to that of terrestrial mammals. In human recreational divers, right ventricular dilatation is induced by diving. We hypothesized that the dolphin's heart is in a state similar to that of the right heart dilatation in terrestrial animals. The dolphin electrocardiogram waveform was considered to be due to right axis deviation. Based on the above, we concluded that the dolphin electrocardiogram waveform was due to its ability to live in water. We found that the dolphins are genetically related to ungulates, particularly the hippopotamus, but that their hearts have evolved differently.

Aortic valve insufficiency caused by a hypoplastic aortic valve in a calf.

A 1-month-old crossbred calf was referred for examination due to marked systolic heart murmurs and poor growth. The heart murmur was most audible on the right side of the cranial thorax. Cardiomegaly was evident on chest radiography, and echocardiography demonstrated aortic regurgitation and decreased fractional shortening. Cardiomegaly, aortic root dilation and cardiac displacement were confirmed by computed tomography. At necropsy, the heart was enlarged, and all three aortic valve leaflets were irregularly shaped. In calves with chronic aortic insufficiency, remodeling displacement of the heart and aorta causes changes in the location and timing of heart murmurs. Therefore, aortic insufficiency cannot be ruled out when a systolic heart murmur can be observed in the right chest wall.

Cynomolgus macaque model of neuronal ceroid lipofuscinosis type 2 disease.

Neuronal ceroid lipofuscinoses (NCLs) are autosomal-recessive fatal neurodegenerative diseases that occur in children and young adults, with symptoms including ataxia, seizures and visual impairment. We report the discovery of cynomolgus macaques carrying the CLN2/TPP1 variant and our analysis of whether the macaques could be a new non-human primate model for NCL type 2 (CLN2) disease. Three cynomolgus macaques presented progressive neuronal clinical symptoms such as limb tremors and gait disturbance after about 2 years of age. Morphological analyses using brain MRI at the endpoint of approximately 3 years of age revealed marked cerebellar and cerebral atrophy of the gray matter, with sulcus dilation, gyrus thinning, and ventricular enlargement. Histopathological analyses of three affected macaques revealed severe neuronal loss and degeneration in the cerebellar and cerebral cortices, accompanied by glial activation and/or changes in axonal morphology. Neurons observed throughout the central nervous system contained autofluorescent cytoplasmic pigments, which were identified as ceroid-lipofuscin based on staining properties, and the cerebral cortex examined by transmission electron microscopy had curvilinear profiles, the typical ultrastructural pattern of CLN2. These findings are commonly observed in all forms of NCL. DNA sequencing analysis identified a homozygous single-base deletion (c.42delC) of the CLN2/TPP1 gene, resulting in a frameshifted premature stop codon. Immunohistochemical analysis showed that tissue from the affected macaques lacked a detectable signal against TPP1, the product of the CLN2/TPP1 gene. Analysis for transmission of the CLN2/TPP1 mutated gene revealed that 47 (49.5%) and 48 (50.5%) of the 95 individuals genotyped in the CLN2-affected macaque family were heterozygous carriers and homozygous wild-type individuals, respectively. Thus, we identified cynomolgus macaques as a non-human primate model of CLN2 disease. The CLN2 macaques reported here could become a useful resource for research and the development of drugs and methods for treating CLN2 disease, which involves severe symptoms in humans.

Neuronal ceroid lipofuscinosis in Border Collie dogs in Japan: clinical and molecular epidemiological study (2000-2011).

Neuronal ceroid lipofuscinosis (NCL) is an inherited, neurodegenerative lysosomal disease that causes premature death. The present study describes the clinical and molecular epidemiologic findings of NCL in Border Collies in Japan for 12 years, between 2000 and 2011. The number of affected dogs was surveyed, and their clinical characteristics were analyzed. In 4 kennels with affected dogs, the dogs were genotyped. The genetic relationships of all affected dogs and carriers identified were analyzed. The survey revealed 27 affected dogs, but there was a decreasing trend at the end of the study period. The clinical characteristics of these affected dogs were updated in detail. The genotyping survey demonstrated a high mutant allele frequency in examined kennels (34.8%). The pedigree analysis demonstrated that all affected dogs and carriers in Japan are related to some presumptive carriers imported from Oceania and having a common ancestor. The current high prevalence in Japan might be due to an overuse of these carriers by breeders without any knowledge of the disease. For NCL control and prevention, it is necessary to examine all breeding dogs, especially in kennels with a high prevalence. Such endeavors will reduce NCL prevalence and may already be contributing to the recent decreasing trend in Japan.

Ultrasound-guided, Transabdominal, Intrauterine Artificial Insemination for Cynomolgus Macaques (Macaca fascicularis) Based on Estimated Timing of Ovulation.

Intrauterine sperm injection for artificial insemination is difficult in cynomolgus macaques (Macaca fascicularis) and rhesus macaques (M. mulatta) due to the complex structure of the cervical canal, which differs from that of humans. Despite the availability of several artificial insemination methods for macaques, pregnancy rates are inconsistent, and details regarding ovulation are unclear, thus warranting more effective methods. Therefore, we developed an effective, ultrasound-guided, transabdominal intrauterine artificial insemination method for cynomolgus macaques that involves timing sperm injection to coincide with the periovulation phase estimated according to rapid hormone measurement. We performed our intrauterine artificial insemination on 6 female macaques; 4 of the 5 animals that were predicted to have ovulated soon after insemination became pregnant, whereas the 1 macaque that was predicted not to have ovulated did not. Furthermore, we saw no evidence of injury, such as a conspicuous needle hole or bleeding on the surface of or inside the uterus, nor did our method result in any abnormalities in the mothers or their offspring. Thus, our ultrasound-guided, transabdominal, intrauterine artificial insemination method is rapid, safe, and effective in cynomolgus macaques.

Prevalence and risk factors for feather-damaging behavior in psittacine birds: Analysis of a Japanese nationwide survey.

A case control study was conducted to estimate the prevalence of feather-damaging behavior and evaluate the correlation with risk factors among pet psittacine birds in Japan. Although feather-damaging behavior among pet parrots is frequently observed in Japan, its prevalence and potential risk factors have not been investigated. Therefore, we conducted an online questionnaire survey on parrot owners throughout Japan to examine regional differences in feather-damaging behavior and associated risk factors. In total, 2,331 valid responses were obtained. The prevalence of feather-damaging behavior was 11.7%, in general agreement with prior studies. The highest prevalence was among Cockatoos (Cacatua spp., etc.; 30.6%), followed by Lovebirds (Agapornis spp.; 24.5%) and African grey parrots (Psittacus erithacus; 23.7%). Multivariate logistic regression was carried out to calculate the adjusted odds ratio (ORadj) for potential risk factors and adjust the confounding of the variables. The odds of feather-damaging behavior were significantly higher for Conures (Aratinga spp., Pyrrhura spp., Thectocercus acuticaudatus, Cyanoliseus patagonus) (ORadj = 2.55, P = 0.005), Pacific parrotlets (Forpus coelestis) (ORadj = 3.96, P < 0.001), African grey parrots (ORadj = 6.74, P < 0.001), Lovebirds (ORadj = 6.79, P < 0.001) and Cockatoos (ORadj = 9.46, P < 0.001) than Budgerigars (Melopsittacus undulatus), and for young adults (ORadj = 1.81, P = 0.038) and adults (ORadj = 3.17, P < 0.001) than young birds, and for signs of separation anxiety (ORadj = 1.81, P < 0.001). Species, bird age and signs of separation anxiety were significantly higher risk factors for feather-damaging behavior than any other potential risk factors. Our findings, which include broad species diversity, are a good source of data for predicting risk factors for feather-damaging behavior and could be useful in preventing declines in welfare.

Activation of canine neutrophils by platelet-activating factor.

Neutrophils are essential for innate immunity as the first line of defence. Neutrophils act as phagocytic white blood cells to kill bacteria and other microorganisms. A strong respiratory burst of neutrophils, dependent on reactive oxygen species, is produced during phagocytosis. Platelet-activating factor (PAF) is a signalling molecule with several prominent roles in tissue injury, inflammation, and platelet aggregation. However, the detailed mechanisms and intracellular signalling pathways involved in PAF-mediated neutrophil activation remain unclear. Here, we investigated the effect of PAF on changes in calcium concentration ([Ca2+]i) and oxygen radical (O2-) generation in activating canine neutrophils. We further evaluated these effects of PAF with inhibition of G protein-coupled receptors using the specific inhibitor suramin. Blood samples were collected from a total of five dogs and neutrophils were isolated. PAF stimulation of canine neutrophils caused an increase in [Ca2+]i as well as the generation of O2-, and the PAF receptor was sensitive to suramin. The results suggested that PAF stimulation of canine neutrophils may cause Ca2+ influx from the endoplasmic reticulum into the cytoplasm (as the first wave) and then trigger store-operated Ca2+ entry (as the second wave), which is an important intracellular signal transduction pathway for neutrophil activation. Furthermore, O2- generation by PAF stimulation may depend on the intracellular signalling pathway, with increasing inositol trisphosphate levels and [Ca2+]i via G protein-coupled receptors. The finding that PAF-activating platelet aggregation is involved in canine neutrophil activation suggests a close relationship between haemostasis and neutrophil activation in dogs, offering new insight into the response to infection.

Usefulness of cardiac hormones for evaluating valvular disease in cynomolgus monkeys (Macaca fascicularis).

Nonhuman primates are commonly used as experimental animals due to their biological resemblance to humans. In patients with cardiac disease, the levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) tend to increase in response to cardiac damage, and they are thus used as indicators for the diagnosis of human heart failure. However, no reference values for ANP and BNP have been reported for heart disease in nonhuman primates. In this study, we recorded the age, sex, and body weight of 202 cynomolgus monkeys, and performed evaluations to assess the ANP and BNP levels, electrocardiography and echocardiography, and accordingly divided the monkeys into two groups: healthy monkeys and those with spontaneous cardiac disease. Statistical analysis was performed to determine the relationship of ANP and BNP with the factors of age, sex, and body weight. No significant relationship was found between the levels of ANP and BNP and the factors of age, sex, and body weight. However, both the ANP and BNP levels were significantly different between the healthy monkeys and monkeys with valvular disease. Similar to humans, the ANP and BNP levels tended to increase with the progression of cardiac disease in monkeys. Based on these results, we concluded that ANP and BNP are indicators of cardiac disease in nonhuman primates, and that this nonhuman primate cardiac disease model is applicable for cardiology research in humans.

Establishment of vertebral heart scale in the growth period of the Japanese macaque (Macaca fuscata).

We performed a thoracic X-ray examination of 56 Japanese macaques to obtain normal reference values for vertebral heart scale (VHS). Mean VHS was 10.25 +/- 0.94 v. In males, mean VHS was 10.56 +/- 0.73 v, with no significant correlation to age or weight. In contrast, mean VHS in females was 9.97 +/- 1.03 v, and tended to decrease with increasing age and weight. These findings will facilitate the diagnosis of cardiac disease in Japanese macaques in the future.

Establishment of a new formula for QT interval correction using a large colony of cynomolgus monkeys.

The demand for monkeys for medical research is increasing, because their ionic mechanism of repolarization is similar to that of humans. The QT interval is the distance between the Q wave and T wave, but this interval is affected by heart rate. Therefore, QT correction methods are commonly used in clinical settings. However, an accurate correction formula for the QT interval in cynomolgus monkeys has not been reported. We assessed snapshot electrocardiograms (ECGs) of 353 ketamine-immobilized monkeys, including aged animals, and contrived a new formula for the corrected QT interval (QTc) as a marker of QT interval prolongation in cynomolgus monkeys. Values for QTc were calculated using the formula [QTc] = [QT] / [RR]n, along with several other formulas commonly used to calculate QTc. We found that the optimal exponent of the QT interval corrected for heart rate, n, was 0.576. The mean value of QTc in healthy monkeys determined using the new formula was 373 ± 31 mm, and there were no significant differences between the sexes. Other ECG parameters were not significantly different between the sexes and there were no age-related effects on QTc. Prolongation of QTc to over 405 ms, as calculated by the new formula, was observed in 50 monkeys with underlying diseases. Additionally, all monkeys with QTc above 440 ms by the new formula had some underlying disease. The results resemble those in humans, suggesting that the new QTc formula could be useful for diagnosis of QT interval prolongation in cynomolgus monkeys.

Echocardiographic evaluation of cardiac function in cynomolgus monkeys over a wide age range.

Various cardiovascular diseases can be detected and diagnosed using echocardiography. The demand for cardiovascular system research using nonhuman primates is increasing, but echocardiographic references for nonhuman primates are limited. This report describes the first comparison of echocardiographic reference values in 247 normal cynomolgus monkeys (135 females, 112 males) over a wide age range. Echocardiography, electrocardiography, blood pressure and chest X-ray images were acquired under immobilization with intramuscular ketamine hydrochloride, then cardiac structure, function, and flow velocity were assessed. Cardiac hormone levels were also tested. We found that cardiac structures positively correlated with weight, that the size of these structures stabilized after reaching maturity and that cardiac output increased according to heart size. In contrast, fractional shortening of the left ventricle, ejection fraction and flow velocity showed no significant correlations with weight or age, and age and E wave correlated negatively. These findings appear sufficiently similar to those in humans to suggest that cynomolgus monkeys can serve as a suitable model of human cardiac disease. Our data should also prove useful for surveying cardiac dysfunction in monkeys.

The effect of 7.2% hypertonic saline solution with 6% dextran 70 on cardiac contractility as observed by an echocardiography in normovolemic and anesthetized dogs.

We studied the effect of a small volume of 7.2% hypertonic saline solution (HSS) or HSS with 6% dextran 70 (HSD) on hemodynamic status, especially on cardiac contractility, in anesthetized dogs using the left ventricular end-systolic volume index (ESVI) and ejection fraction (EF), which can be obtained in noninvasive echocardiography. In the present study, the mean values of ESVI were unaffected by HSS and HSD infusion, whereas the left ventricular end-diastolic volume index (EDVI) was markedly and significant increased. As a result of the changes in EDVI but not in ESVI, EF increased transiently and significantly in the HSS and HSD group, whereas no such significant change was observed in the dogs that received isotonic saline solution. In addition, as a result of the increases in cardiac index but not arterial pressure, system vascular resistances (SVR) decreased transiently and significantly in the HSS and HSD groups, whereas no such significant change was observed in the ISS group. Therefore, the positive inotropic effects of HSS and HSD may be attributable to the increase in left ventricular preload and decreases in SVR rather than direct changes in myocardial contractility.

Usage of high-performance mattresses for transport of Indo-Pacific bottlenose dolphin.

Ground transport can be a stressful operation for dolphins if the long period of restraint causes damage to internal organs, especially to the lung, generated by their own weight. Buoyancy is deprived from dolphins under moist transport, in which dolphins are transported on mattresses. Upgrading mattresses is an effective way to modify the transportation method so as to compensate for the loss of buoyancy. In Indo-Pacific bottlenose dolphins (Tursiops aduncus), we tried to find mattresses that performed well at distributing the dolphins' weight and preserved their pulmonary function. When using EV-17 (thickness, 50 mm) put on EE-20 (thickness, 50 mm), a wider support area, less extreme changes in pressure, and lower maximum pressures were observed compared with other mattress systems tested. On this mattress system, lower breathing rates, lower heart rates, and higher exhaled CO(2) concentrations were shown compared with using standard mattresses. These results suggest that the performance of the combination of EV-17 and EE-20 is better than that of the standard mattress in terms of the cardiopulmonary function of dolphins. Zoo Biol 27:331-340, 2008. (c) 2008 Wiley-Liss, Inc.

Utility of arterial blood gas, CBC, biochemistry and cardiac hormones as evaluation parameters of cardiovascular disease in nonhuman primates.

Cardiovascular disease (CVD) has a tremendous impact on the quality of life of humans. While experimental animals are valuable to medical research as models of human diseases, cardiac systems differ widely across various animal species. Thus, we examined a CVD model in cynomolgus monkeys. Laboratory primates are precious resources, making it imperative that symptoms of diseases and disorders are detected as early as possible. Thus, in this study we comprehensively examined important indicators of CVD in cynomolgus monkeys, including arterial blood gas, complete blood count (CBC), biochemistry and cardiac hormones. The control group included 20 healthy macaques showing non-abnormal findings in screening tests, whereas the CVD group included 20 macaques with valvular disease and cardiomyopathy. An increase of red blood cell distribution width was observed in the CBC, indicating chronic inflammation related to CVD. An increase of HCO3 was attributed to the correction of acidosis. Furthermore, development of the CVD model was supported by significant increases in natriuretic peptides. It is suggested that these results indicated a correlation between human CVD and the model in monkeys. Moreover, blood tests including arterial blood gas are non-invasive and can be performed more easily than other technical tests. CVD affected animals easily change their condition by anesthesia and surgical invasion. Pay attention to arterial blood gas and proper respond to their condition are important for research. This data may facilitate human research and aid in the management and veterinary care of nonhuman primates.

Superparamagnetic Iron Oxide-enhanced Magnetic Resonance Imaging of Spontaneous Hepatic Neoplasia in a Cynomolgus Macaque (Macaca fascicularis).

Although the number of reports describing tumors in aged NHP has increased, spontaneous neoplasias in NHP are extremely rare, with the notable exception of prosimians, in which spontaneous hepatic neoplasms arise. In addition to radiography and ultrasonography, superparamagnetic iron oxide (SPIO)-enhanced MRI tends to be applied in human practice to non-invasively locate, identify, and size liver tumors and to define the border between neoplastic and normal tissues. Here we report a 13-y-old female cynomolgus monkey with anorexia and serologically normal liver enzymes. After fluid therapy, the condition remained in remission for several months. Later, however, a palpable mass was assessed by using ultrasonography, radiology, and SPIO-MRI; T2-weighted images revealed a clear border between a hepatocellular carcinoma and normal liver tissue. Findings at necropsy supported the imaging data. Serologic assessment after euthanasia revealed a positive reaction to an abnormal form of prothrombin (PIVKA-II). We recommend SPIO-MRI as a practical and useful for diagnosing hepatocellular neoplasias in NHP. This study is the first to demonstrate the applicability of SPIO-MRI for the identification of hepatocellular carcinoma in NHP.

Three-dimensional CT examination of the mastication system in the giant anteater.

The gross anatomy of the mastication system of the giant anteater (Myrmecophaga tridactyla) was examined by means of three-dimensional image analysis. The anteater rotates the mandibles medially and laterally to control its tongue when it is elongated and to house it when it is relaxed. Three-dimensional CT image analysis demonstrated that the shape and size of the oral cavity changes drastically when the mandibles are rotated. The oral cavity expands bilaterally when the dorsal part of the mandibles bend medially. Macroscopic observations and muscle-weight data supported the observation that the superficial temporal and medial pterygoid muscles act as the main medial and lateral rotators of the mandible, respectively. The low height of the mandibular ramus and the incomplete zygomatic arch in this species represent adaptations for the rotational movement of the mandibles, since they both contribute to the medially oriented transmission of force from the temporal muscles and to preventing collision between the mandibles and the cranium during the rotational movement.

Clinical evaluation of left ventricular moderator band in 12 dogs.

We retrospectively examined clinical data for 12 dogs in which echocardiography revealed the presence of left ventricular moderator bands (LMB). Physical examinations, electrocardiography and echocardiography revealed slight cardiac murmurs, increasing QRS complex and left ventricular turbulent flow (6 of the dogs), respectively. No differences were observed with respect to gender, and no specific clinical symptoms or types of dog that frequently develop this disorder were found.