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The mammalian skull is very malleable and has notably radiated into highly diverse morphologies, fulfilling a broad range of functional needs. Although gnawing is relatively common in mammals, this behavior and its associated morphology are diagnostic features for rodents. These animals possess a very versatile and highly mechanically advantageous masticatory apparatus, which, for instance, allowed caviomorph rodents to colonize South America during the Mid-Eocene and successfully radiate in over 200 extant species throughout most continental niches. Previous work has shown that differences in bite force within caviomorphs could be better explained by changes in muscle development than in mechanical advantages (i.e., in cranial overall morphology). Considering the strong bites they apply, it is interesting to assess how the reaction forces upon the incisors (compression) and the powerful adductor musculature pulling (tension) mechanically affect the cranium, especially between species with different ecologies (e.g., chisel-tooth digging). Thus, we ran finite element analyses upon crania of the subterranean Talas' tuco-tuco Ctenomys talarum, the semi-fossorial common degu Octodon degus, and the saxicolous long-tailed chinchilla Chinchilla lanigera to simulate: (A) in vivo biting in all species, and (B) rescaled muscle forces in non-ctenomyid rodents to match those of the tuco-tuco. Results show that the stress patterns correlate with the mechanical demands of distinctive ecologies, on in vivo-based simulations, with the subterranean tuco-tuco being the most stressed species. In contrast, when standardizing all three species (rescaled models), non-ctenomyid models exhibited a several-fold increase in stress, in both magnitude and affected areas. Detailed observations evidenced that this increase in stress was higher in lateral sections of the snout and, mainly, the zygomatic arch; between approximately 2.5-3.5 times in the common degu and 4.0-5.0 times in the long-tailed chinchilla. Yet, neither species, module, nor simulation condition presented load factor levels that would imply structural failure by strong, incidental biting. Our results let us conclude that caviomorphs have a high baseline for mechanical strength of the cranium because of the inheritance of a very robust "rodent" model, while interspecific differences are associated with particular masticatory habits and the concomitant level of development of the adductor musculature. Especially, the masseteric and zygomaticomandibular muscles contribute to >80% of the bite force, and therefore, their contraction is responsible for the highest strains upon their origin sites, that is, the zygomatic arch and the snout. Thus, the robust crania of the subterranean and highly aggressive tuco-tucos allow them to withstand much stronger forces than degus or chinchillas, such as the ones produced by their hypertrophied jaw adductor muscles or imparted by the soil reaction.

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Chronic tympanic membrane perforation represents a prevalent otological condition, necessitating a reliable animal model for the validation and safety assessment of surgical techniques and materials employed in myringoplasty. This prospective study involved the establishment of chronic tympanic membrane perforation animal models in 16 chinchillas. A thermic myringotomy was conducted on the right ear (study group), followed by cold instrument myringotomy, coupled with the topical application of mitomycin C and dexamethasone solution on the left ear (control group). Results revealed that tympanic membrane perforations in the study group persisted for a minimum of 4 weeks in 93.7% of cases and extended to 12 weeks in 62.5% of the cases. In contrast, all tympanic membrane perforations in the control group were present at 4 weeks, with only 37.5% persisting after 12 weeks, although statistical tests did not find significant differences between the two groups (chi-square: p-value = 0.157, Kruskal-Wallis: p-value = 0.093, Mann-Whitney: p-value = 0.121). The thermic myringotomy employed to induce chronic tympanic membrane perforation in animals demonstrated efficiency and sustainability. This model, characterized by stability and reproducibility, holds promise for future experimental applications in the field.

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Few instances of neoplastic formations in the liver of chinchillas have been found, even though the species is widely used in different scientific experiments. In the present article we investigate the anatomical features of the chinchilla's liver using CT and three dimension (3D) imaging. For the trials we used 12 (six males and six females) clinically healthy chinchillas all at 18 months of age. The animals were positioned in dorsal recumbency. We used Th8 to L2 vertebrae and the sternum as bone markers for the transverse CT study. The investigated anatomical landmarks for the CT coronal study were the vertebrae, costal arch, soft abdominal wall, diaphragm, stomach and the right kidney. 3D reconstructions were accomplished with a specific imaging software. On transverse and coronal CT images, the chinchilla's liver was composed of lobus hepatis sinister lateralis, 'middle lobe'-without proper Latin term in NAV 2017, lobus hepatis dexter and lobus caudatus. The 'middle lobe' was separated into the 'left middle lobe' and the 'right middle lobe'. Lobus hepatis dexter consisted of lobus hepatis dexter medialis and lobus hepatis dexter lateralis. There was an anatomical relation between the liver, fundus ventriculi and corpus ventriculi. Proc. caudatus was in close contact with the right kidney. Vesica fellea was elongated and ellipsoid. 3D reformatted images confirmed the results obtained by transverse and coronal CT studies. The CT density of the liver in HU was 195.6 ± 73.1. The CT and 3D reconstructed images were visualized at high resolution. This data could be used as a basis for further morphological and imaging studies.

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This article reviews the development, hand-rearing, feeding, housing, and social behavior of common pet rodent species (rats, mice, hamsters, gerbils, guinea pigs, chinchillas, and degus). In addition, common gastrointestinal, respiratory, cardiovascular, dermatologic, musculoskeletal, neurologic, and ophthalmic disorders in pediatric pet rodents are reviewed. Preventative care and indications for spaying and neutering are discussed.

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INTRODUCTION: A large variety of pet feeds is commercially available for pet herbivores; these feeds may differ in nutrient composition from the natural diet, and may trigger different feeding behaviours than observed in natural habitats. Here, we surveyed literature on the natural diet and activity budget of rabbits (Oryctolagus cuniculus), guinea pigs (Cavia porcellus), chinchilla (Chinchilla lanigera) and degus (Octodon degus), as well as 260 compound feeds commercially available for these species between 1982 and 2020. The species are classified as herbivores, with available data on natural diets suggesting a crude fibre (CF) level of approximately 250 g/kg dry matter (DM), natural feeding activity at a magnitude of 4-7 h per day, with distinctively shorter feeding when fed on compound pet feeds. Only for a minority of feeds did the first 5 listed ingredients not include a starchy ingredient, or only ingredients not considered suitable for human consumption. The percentage of feeds whose CF level was less than 150 g/kg DM was 22 % for production rabbits, 18 % for pet rabbits, 26 % for guinea pigs, 18 % for chinchillas and 14 % for degus; in other words, a majority of currently marketed products have CF levels in accord with published recommendations, even if that means a discrepancy to natural diets. Screening the producers' feeding instructions suggests they should generally not be followed uncritically. No temporal trends in the CF levels of these diets was evident. There is no consensus whether only products resembling natural diet items should be included in pet feeds, or whether vegetable byproducts not edible by humans should also be included. The observed practice of pet feed composition largely did not follow either concept, questioning the general rationale of pet feed composition. Whole forage like hay is recommended as the main diet component for these species, and 76 % of pet feed products noted that hay should be fed in the feeding instructions.

INTRODUCTION: Une grande variété d'aliments pour animaux de compagnie est disponible dans le commerce pour les herbivores de compagnie; ces aliments peuvent différer du régime naturel dans leur composition en nutriments et peuvent déclencher des comportements alimentaires différents de ceux observés dans les habitats naturels. Nous avons étudié la littérature sur le régime alimentaire naturel et le budget d'activité des lapins (Oryctolagus cuniculus), des cochons d'Inde (Cavia porcellus), des chinchillas (Chinchilla lanigera) et des dégus (Octodon degus), ainsi que 260 aliments composés disponibles dans le commerce pour ces espèces entre 1982 et 2020. Les espèces sont classées comme herbivores et les données disponibles sur leurs régimes alimentaires naturels suggèrent une teneur en fibres brutes (FB) d'environ 250 g/kg de matière sèche (MS), une activité alimentaire naturelle de l'ordre de 4 à 7 heures par jour, avec une durée d'alimentation nettement plus courte lorsque l'animal est nourri avec des aliments composés pour animaux de compagnie. Ce n'est que pour une minorité d'aliments que les cinq premiers ingrédients énumérés ne comprenaient pas d'ingrédient amylacé, ou seulement des ingrédients considérés comme impropres à la consommation humaine. Le pourcentage d'aliments dont la teneur en FB était inférieure à 150 g/kg MS était de 22 % pour les lapins de production, 18 % pour les lapins de compagnie, 26 % pour les cochons d'Inde, 18 % pour les chinchillas et 14 % pour les dégus ; en d'autres termes, la majorité des produits actuellement commercialisés ont des teneurs en FB conformes aux recommandations publiées, même si cela signifie une divergence par rapport aux régimes naturels. L'examen des instructions d'alimentation des producteurs suggère qu'elles ne doivent généralement pas être suivies sans discernement. Aucune évolution temporelle dans les teneurs en FB de ces régimes n'a été mise en évidence. Il n'y a pas de consensus sur la question de savoir si seuls les produits ressemblant à des aliments naturels doivent être inclus dans les aliments pour animaux de compagnie ou si des sous-produits végétaux non comestibles pour l'homme doivent également être inclus. La pratique observée en matière de composition des aliments pour animaux de compagnie n'a en grande partie respecté aucun de ces deux concepts, ce qui remet en question la logique générale de la composition de ces aliments. Les fourrages entiers, comme le foin, sont recommandés comme principale composante de l'alimentation de ces espèces et 76 % des produits alimentaires pour animaux de compagnie indiquent, dans les instructions d'alimentation, que du foin doit être donné.

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PURPOSE: Hymenolepis (Rodentolepis) nana is an enteric tapeworm globally widespread in wild and captive rodents. The survey was carried out in three chinchilla breeding facilities and in one sugar glider breeding facility in Central and Southern Italy. METHODS: One hundred and four chinchilla fecal pools and 40 sugar glider fecal pools were collected from cages housing breeding pairs or females with their offspring. Fecal samples were examined with a qualitative and quantitative copromicroscopical approach. Hymenolepis eggs were identified based on morphological and morphometrical features, and the average number of eggs per gram (EPG) of feces was estimated. RESULTS: Hymenolepis nana eggs were detected in 39.42% of chinchilla samples with an average of 16.33 EPG; whereas, all of the sugar glider samples tested positive with an average of 454.18 EPG. Neither helminth eggs nor protozoan cysts/oocysts were detected in any of the breeding facilities. CONCLUSION: The results clearly show a diffuse parasitism in both chinchillas and sugar gliders, and should be taken into consideration given the rising popularity of these two pet species combined with the zoonotic complications presented by H. nana.

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Background: A cataract is one of the underlying causes of blindness in animals. Phacoemulsification is the standard procedure in cataract surgery for humans and animals. This procedure has been used to restore vision in cataracts in a variety of animals. However, this technique is difficult in very small animals, such as rodents, due to their small eyes. Case Description: A 4-year-old male domestic chinchilla was presented with cloudiness in the lenses for 1 month. The ophthalmic examination revealed cataracts (oculus uterque: both eyes). Positive dazzle reflex oculus sinister; left eye (OS) and negative reflex oculus dexter; right eye (OD) were noted. The electroretinography was low amplitude OS whereas a flat waveform presented OD. In this case, cataract surgery was performed using phacoemulsification without intraocular lens implantation OS. Postoperative, the chinchilla was alert and could jump on and jump off the ledge in a house. When the veterinarian approached closely to OS, the chinchilla displayed an erect body posture and open eyes, whereas the chinchilla was ignored when the veterinarian doing the same OD. The chinchilla was alert and had improved vision observe by this chinchilla can jump on and jump off the ledge in his house throughout the follow-up period 18 months later. Conclusion: In this chinchilla, phacoemulsification was successfully performed and resulted in better overall vision. The chinchilla was alert and could jump on and jump off the ledge in a house after cataract surgery throughout the follow-up period of 18 months.

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The trapezoid body (TB) contains axons of neurons residing in the anteroventral cochlear nucleus (AVCN) that provide excitatory and inhibitory inputs to the main monaural and binaural nuclei in the superior olivary complex (SOC). To understand the monaural and binaural response properties of neurons in the medial and lateral superior olive (MSO and LSO), it is important to characterize the temporal firing properties of these inputs. Because of its exceptional low-frequency hearing, the chinchilla (Chinchilla lanigera) is one of the widely used small animal models for studies of hearing. However, the characterization of the output of its ventral cochlear nucleus to the nuclei of the SOC is fragmentary. We obtained responses of TB axons to stimuli typically used in binaural studies and compared these responses to those of auditory nerve (AN) fibers, with a focus on temporal coding. We found enhancement of phase-locking and entrainment, i.e., the ability of a neuron to fire action potentials at a certain stimulus phase for nearly every stimulus period, in TB axons relative to AN fibers. Enhancement in phase-locking and entrainment are quantitatively more modest than in the cat but greater than in the gerbil. As in these species, these phenomena occur not only in low-frequency neurons stimulated at their characteristic frequency but also in neurons tuned to higher frequencies when stimulated with low-frequency tones, to which complex phase-locking behavior with multiple modes of firing per stimulus cycle is frequently observed.NEW & NOTEWORTHY The sensitivity of neurons to small time differences in sustained sounds to both ears is important for binaural hearing, and this sensitivity is critically dependent on phase-locking in the monaural pathways. Although studies in cat showed a marked improvement in phase-locking from the peripheral to the central auditory nervous system, the evidence in rodents is mixed. Here, we recorded from AN and TB of chinchilla and found temporal enhancement, though more limited than in cat.

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Although for many years, researchers have been working on understanding the function of the cocaine- and amphetamine-regulated transcript (CART) peptide at the central- and peripheral-nervous-system level, data describing the presence of CART in the claustrum are still missing. Therefore, the aim of the present study was to immunohistochemically investigate the CART expression in the claustrum neurons in chinchillas as well as the CART co-localization with somatostatin (SOM), parvalbumin (PV), and neuropeptide Y (NPY) using double-immunohistochemical staining. The claustrum is divided into two main parts: the dorsal segment (CL), which is located above the rhinal fissure, and the ventral segment (EN), located below the rhinal fissure. The presence of HU C/D-IR CART-IR-positive neurons was detected in both the insular claustrum (CL) and the endopiriform nucleus (EN). The vast majority of CART-IR neurons were predominantly small and medium in size and were evenly scattered throughout the claustrum. CART co-localization with selected neurotransmitters/neuromodulators (SOM, NPY, and PV) showed the presence of a CART-IR reaction only in the neurons, while the nerve fibers were, in all cases, devoid of the CART-IR response. Our research supplements missing knowledge about the distribution and co-localization pattern of CART with SOM, NPY, and PV in the chinchilla claustrum, and also provides a better understanding of the similarities and differences compared to other species of rodents and other mammals.

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Cochlear implant (CI) surgery is one of the most utilized treatments for severe hearing loss. However, the effects of a successful scala tympani insertion on the mechanics of hearing are not yet fully understood. This paper presents a finite element (FE) model of the chinchilla inner ear for studying the interrelationship between the mechanical function and the insertion angle of a CI electrode. This FE model includes a three-chambered cochlea and full vestibular system, accomplished using µ-MRI and µ-CT scanning technologies. This model's first application found minimal loss of residual hearing due to insertion angle after CI surgery, and this indicates that it is a reliable and helpful tool for future applications in CI design, surgical planning, and stimuli setup.

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The cortex of the limb bones of chinchillas is very thin and brittle, so it is prone to fractures of the limb bones, among which fractures of the tibia, radius and ulna are the most frequent types. When a chinchilla has a closed fracture, it can be immobilized with a splint, cast, or bandage. If the broken end of the fracture pierces the skin, it is best to choose internal fixation or external fixation brackets for treatment. In this report, a 0.661 kg, 2-year-old male uncastrated chinchilla was presented to the Veterinary Teaching Hospital of Huazhong Agricultural University due to an old fracture of the right forearm. With the consent of the owner, we decided to use a 25-gauge needle as an IM pin to fix the fracture. Ten days after surgery, the wound had healed well, and the limb could support body weight, but the palm did not show a grasping position. Twenty four days after the operation, the affected limb had not regained the ability to grasp. The X-ray showed a slight rotation of the IM pin and good callus growth in the ulna, but not in the radius. One month after the operation, it was found that the function of the affected limb of the chinchilla was normal and the grasping ability was restored through follow-up consultation and the return visit.

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Pituitary tumors are rare in chinchillas. This report describes the clinical, gross, histologic, and immunohistochemical characteristics of pituitary tumors in 4 chinchillas. The affected chinchillas were females between 4 and 18 years of age. Clinically, neurologic signs were most commonly reported and included depression, obtundation, seizure, head-pressing, ataxia, and possible blindness. Computed tomography scanning of 2 chinchillas revealed solitary intracranial extra-axial masses in the region of the pituitary gland. Two pituitary tumors were confined to the pars distalis; the other 2 invaded the brain. Based on their microscopic appearances and lack of distant metastases, all 4 tumors were diagnosed as pituitary adenomas. Immunohistochemically, all pituitary adenomas were weakly to strongly positive for growth hormone, most consistent with the diagnosis of somatotropic pituitary adenomas. To the authors' knowledge, this is the first detailed report of the clinical, pathologic, and immunohistochemical features of pituitary tumors in chinchillas.

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This article reviews the most common dermatologic conditions of the pet rodent population, including the prevalence, clinical signs, diagnosis, and treatment recommendations.

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The gastrointestinal microbiota plays an important role in health of the host animals and the detrimental influence of pharmaceutical treatment on the fecal microbiota receives an increasing concern. The clinical use of ivermectin on chinchillas has not yet been evaluated. The purpose of our study was to assess the influence of ivermectin injection on the fecal bacterial microbiota of chinchillas. A with-in subject, before and after study was performed on 10 clinically healthy chinchillas during a 14-day period, all chinchillas received the same ivermectin treatment, and the microbiota from their fecal samples before and after administration were compared as two experimental groups. Fecal samples were collected on day 0 (before ivermectin administration) and day 14 (post ivermectin administration). Fecal bacterial microbiota was analyzed by bacterial 16S rRNA gene sequencing. No clinical abnormalities were observed post subcutaneous administration of ivermectin. No significant alteration was found in the abundance and diversity of fecal bacterial microbiota after treatment, but the dominant position of some bacterial species changed. In conclusion, ivermectin administration was associated with minimal alternations of the fecal bacterial microbiota in healthy chinchillas, and these changes had no observed negative effect on general health of chinchillas in short term.

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Repeated exposures to blast overpressure (BOP) introduce hearing complaints in military service members even with the use of hearing protection devices (HPDs). Although epidemiology and animal studies have been performed to investigate the damage formation mechanism of blast-induced hearing damage, there is still a lack of understanding and therapeutic solutions, especially for HPD-protected ears. Recent studies revealed the potential therapeutic function of liraglutide, a glucagon-like peptide-1 receptor agonist, to facilitate post-blast hearing restoration in chinchillas. This study is a continuation and summary of the previous studies performed by Jiang et al. (2021, 2022) to investigate the damage mitigation function of liraglutide treatment in chinchillas with open and protected ears after repeated low-intensity blast exposures within 28 days of observation. Chinchillas were divided into six experimental groups: pre-blast treatment, post-blast treatment, and blast control with ears open or protected by earplug (EP). All animals were exposed to six consecutive blasts at the level of 3-5 psi (21-35 kPa) on Day 1. Hearing function tests including auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) were performed on Day 1 (pre- and post-blast) and Days 4, 7, 14, and 28 after blast exposure. Results indicated that the damage mitigation function of the liraglutide treatment in the open-ear chinchillas was reflected by the significantly lower ABR threshold shifts in the drug treatment groups than in the blast controls. In EP groups, the higher ABR wave I/V ratio and lower MLR amplitude observed in the drug-treated chinchillas suggested that the post-blast hyperactivities in the auditory system might be potentially ameliorated by the liraglutide treatment. The 28-day-long experiment showed the effect of liraglutide treatment increased with time in both open and EP groups. This study demonstrated that the use of HPDs prevented the blast-induced complications in the middle ear and reduced the damage caused in the central auditory system. The liraglutide treatment showed an effect increasing with time and different outcomes in open and EP chinchillas. This innovation in the animal model of chinchilla provides insights to investigate subtle changes in the higher-level structures of the auditory system.

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INTRODUCTION: The available literature provides relatively little information on the morphology of the autonomic head ganglia in rodents including their neurochemical codding. MATERIAL AND METHODS: Morphological investigations of the otic ganglion of the chinchilla were performed using the modified acetylcholinesterase method. The cellular structure was investigated with histological techniques and neurochemical properties were studied with the double-labelling immunofluorescence method. RESULTS: Macromorphological investigations allowed the otic ganglion to be identified as a compact, oval agglomeration of neurons and nerve fibers. Multidimensional cross-sections revealed densely arranged neuronal perikarya and two populations of nerve cells differing in size were distinguished. The large cells (40-50 µm) accounted for about 80% of the neurons in the cross-sections. Moreover, a small number of intraganglionic nerve fibers was observed. Immunohistochemical staining revealed that over 85% of the neuronal cell bodies in the otic ganglion contained immunoreactivity to VAChT or ChAT. VIP-immunoreactive perikarya comprised approximately 10% of the ganglionic cells. Double staining revealed the presence of VAChT+ and NOS+ neurons which amounted to about 45% of the nerve cells in the otic ganglion. NOS+ only perikarya comprised approx. 15% of all the neurons. Immunoreactivity to enkephalins, substance P, somatostatin, and galanin was expressed in single nerve cell bodies and nerve fibers except numerous substance P+ intraganglionic nerve fibers. Some of them were stained also for CGRP. Single neurons stained for tyroxine hydroxylase. CONCLUSIONS: Our results, compared with findings in other rodent species suggest the existence of interspecies differences in the morphology, cellular structure, and immunohistochemical properties of the head autonomic ganglia in mammals.

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The pattern of normal coronary vascularization in a mammalian heart includes the presence of both right and left coronary arteries. According to the literature data, the presence of single major coronary arteries is mainly related to cardiac abnormalities. Previously it has been reported that the right coronary artery is absent in the coronary vascularization of the heart in the chinchilla. Our research was carried out on thirty chinchillas (Chinchilla laniger Molina). The coronary vessels were filled with colored latex to render them visible. The examinations were supplemented additionally with the use of microcomputed tomography with arterial contrast. Our study demonstrates its undoubtedly presence of the right coronary artery. In all subjects the right coronary artery was present, as was the left coronary artery. Two types of right coronary artery were found. Our results indicate that the normal pattern of coronary vascularization of heart in chinchilla includes both the right and left coronary arteries. An open question remains the presence of single coronary artery is a normal pattern of cardiac arterial vascularization in chinchilla.

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Albert Feng was a prominent comparative neurophysiologist whose research provided numerous contributions towards understanding how the spectral and temporal characteristics of vocalizations underlie sound communication in frogs and bats. The present study is dedicated to Al's memory and compares the spectral and temporal representations of stochastic, complex sounds which underlie the perception of pitch strength in humans and chinchillas. Specifically, the pitch strengths of these stochastic sounds differ between humans and chinchillas, suggesting that humans and chinchillas may be using different cues. Outputs of auditory filterbank models based on human and chinchilla cochlear tuning were examined. Excitation patterns of harmonics are enhanced in humans as compared with chinchillas. In contrast, summary correlograms are degraded in humans as compared with chinchillas. Comparing summary correlograms and excitation patterns with corresponding behavioral data on pitch strength suggests that the dominant cue for pitch strength in humans is spectral (i.e., harmonic) structure, whereas the dominant cue for chinchillas is temporal (i.e., envelope) structure. The results support arguments that the broader cochlear tuning in non-human mammals emphasizes temporal cues for pitch perception, whereas the sharper cochlear tuning in humans emphasizes spectral cues.

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The recurrent evolution of resistance to cardiotonic steroids (CTS) across diverse animals most frequently involves convergent amino acid substitutions in the H1-H2 extracellular loop of Na+,K+-ATPase (NKA). Previous work revealed that hystricognath rodents (e.g., chinchilla) and pterocliform birds (sandgrouse) have convergently evolved amino acid insertions in the H1-H2 loop, but their functional significance was not known. Using protein engineering, we show that these insertions have distinct effects on CTS resistance in homologs of each of the two species that strongly depend on intramolecular interactions with other residues. Removing the insertion in the chinchilla NKA unexpectedly increases CTS resistance and decreases NKA activity. In the sandgrouse NKA, the amino acid insertion and substitution Q111R both contribute to an augmented CTS resistance without compromising ATPase activity levels. Molecular docking simulations provide additional insight into the biophysical mechanisms responsible for the context-specific mutational effects on CTS insensitivity of the enzyme. Our results highlight the diversity of genetic substrates that underlie CTS insensitivity in vertebrate NKA and reveal how amino acid insertions can alter the phenotypic effects of point mutations at key sites in the same protein domain.

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Purpose: To explore the temporal topography of the chorioretinopathy in an animal model of central serous chorioretinopathy (CSC) induced by intravenous injection of adrenalin in the Chinchilla rabbits. Methods: Ten Chinchilla rabbits received a daily intravenous injection of adrenaline at 0.04 mg/kg for 8 weeks. Fluorescence fundus angiography (FFA) and electroretinogram (ERG) were performed every week afterwards to see whether there was fluorescence leakage in the fundus and to evaluate the retinal function. Indocyanine green angiography (ICGA) and optical coherence tomography (OCT) were also conducted to detect the change of choroidal vessels. Finally, the eyes of the rabbits were enucleated to make the retinal sections for histological examination with hematoxylin-eosin (HE) staining. Results: Within 8 weeks of the adrenalin administration, 7 out of the 10 rabbits showed different degrees of fluorescence leakage on FFA. The leakage was more obvious during 2-3 weeks after the adrenalin administration. With the progress of disease, the leakage subsided gradually and a scar-like lesion formed. ICGA revealed the local choroidal ischemia and the dilated choroidal vessels. An obvious detachment of retina and an increased thickness of the choroid were found on OCT, which was most obvious 2 weeks after the adrenalin administration (P<0.01). ERG revealed no obvious decline of the b-wave amplitude before and after the adrenalin administration (P>0.05). A circumscribed retinal detachment, the depigmentation of retinal pigment epithelium and enlarged choroidal vessels were shown by the histological examination. Conclusion: The temporal topography of the chorioretinopathy in the Chinchilla rabbits by intravenous injection of adrenaline somewhat mimicked that of the human CSC, which could enhance its application in the exploration for the pathogenesis and the therapeutic measures for human CSC.

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