Protein requirements for Blue-fronted Amazon (Amazona aestiva) growth

The objective of this study was to evaluate the protein requirements for hand-rearing Blue-fronted Amazon parrots (Amazona aestiva). Forty hatchlings were fed semi-purified diets containing one of four (as-fed basis) protein levels: 13%, 18%, 23% and 28%. The experiment was carried out in a randomized block design with the initial weight of the nestling as the blocking factor and 10 parrots per protein level. Regression analysis was used to determine relationships between protein level and biometric measurements. The data indicated that 13% crude protein supported nestling growth with 18% being the minimum tested level required for maximum development. The optimal protein concentration for maximum weight gain was 24.4% (p = 0.08; r(2) = 0.25), tail length 23.7% (p = 0.09; r(2) = 0.19), wing length 23.0% (p = 0.07; r(2) = 0.17), tarsus length 21.3% (p = 0.06; r(2) = 0.10) and tarsus width 21.4% (p = 0.07; r(2) = 0.09). Tarsus measurements were larger in males (p < 0.05), indicating that sex must be considered when studying developing psittacines. These results were obtained using a highly digestible protein and a diet with moderate metabolizable energy levels.     

Spontaneous Rhabdomyosarcoma in a Common Marmoset ( Callithrix jacchus )

The common marmoset (Callithrix jacchus) is now widely used in various research fields, including toxicology. However, information about the background pathology of this species is scarce. Here, we report a case of rhabdomyosarcoma that spontaneously occurred in a common marmoset. A 44-month-old male common marmoset was euthanized due to bilateral hind limb paralysis. At necropsy, a 2×2×5-cm intramuscular mass was observed in the lower right back. Histologically, the mass was mainly composed of interlacing bundles of spindle-shaped tumor cells. Immunohistochemically, the tumor cells were positive for myogenin, desmin, vimentin and alpha-smooth muscle actin. Ultrastructurally, the tumor cells contained bundles of myofilaments with Z-band-like structures. Thus, the tumor was diagnosed as a rhabdomyosarcoma. To our knowledge, this is the first report of spontaneous rhabdomyosarcoma that was definitely diagnosed in the common marmoset.     

Localization of connexin 32 in spontaneous liver lesions of mice

We examined the localization of connexin 32 (Cx32), a component of gap junctions, in 24-month-old male B6C3F1 mice with spontaneously occurring hepatocellular altered foci or tumors. Immunohistochemically, Cx32-staining intensity in cell-to-cell membranes of altered hepatocytes was decreased in eosinophilic foci and increased in basophilic foci as compared to those in intact hepatocytes. These alterations were enhanced in adenomas and carcinomas with both eosinophilic and basophilic cytoplasm. In cell membranes facing on the sinusoidal portions, the intensities increased in all lesions. Image analyses confirmed that the spot areas of Cx32 were decreased in eosinophilic foci, but increased in basophilic foci, adenomas and carcinomas. These results demonstrate that Cx32 shows different expression in different types of hepatic lesions.     

Cholangiocarcinoma in a blue-fronted Amazon parrot (Amazona estiva)

A case of cholangiocarcinoma in a 3-year-old blue-fronted Amazon parrot (Amazona estiva) is reported. Neoplastic tissue was limited to the liver, where it infiltrated and replaced much of the hepatic parenchyma. The only other reported cases of cholangiocarcinoma in an Amazon parrot (Amazona xanthops) also occurred in a bird in its fourth year of age.     

Spontaneous Extraskeletal Osteosarcoma in a Rabbit (Oryctolagus cuniculus): Histopathological and Immunohistochemical Findings

A spontaneously occurring subcutaneous mass in the left forelimb of a nine-year-old rabbit (Oryctolagus cuniculus) was examined histopathologically and immunohistochemically. Clinically, edema and hemorrhage were seen around the mass. No connection of the tumor mass to the appendicular skeleton was found. The tumor was arranged in a solid growth pattern and irregular bundles, and neoplastic cells were polygonal to spindle-shape. Osteoid (positive for osteocalcin) and multinucleated giant cells were diffusely or focally seen. Neoplastic cells were positive for vimentin, osterix and Ki-67, indicating the nature of osteoblasts with proliferating activity, but negative for α-smooth muscle actin, desmin or CD204. Based on these findings, a diagnosis of extraskeletal osteosarcoma was made, a very rare tumor both in laboratory and pet rabbits.     

Cholangiocarcinoma in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis)

A cholangiocarcinoma was diagnosed in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis). Histologically, neoplastic cells effaced hepatocellular architecture. Ultrastructurally, variably dilated bile ductules were lined by simple cuboidal to low columnar ciliated epithelial cells with sparse cellular organelles and prominent junctional complexes. Elongated single cilia arising from basal bodies in the apical cytoplasm were occasionally evident. The presence of such a neoplasm in a 4-month-old parrot is extremely unusual.     

Intradermal skin testing in Hispaniolan parrots (Amazona ventralis)

The purpose of this study was to develop and standardize a protocol for intradermal skin testing in birds. Forty clinically normal Hispaniolan Amazon parrots were anaesthetized and tested by intradermal injection with 0.02 mL of phosphate-buffered saline, histamine phosphate, compound 48/80, codeine phosphate, deionized water, antiavian IgG and rabbit serum. Injection sites were evaluated at 5, 10 and 15 min, 4–6, 24 and 48 h following injection using callipers to measure the diameter of the wheals. A second intradermal skin test was repeated in 20 birds with 0.03 mL of saline, compound 48/80 and codeine phosphate. This study provides the basis for an appropriate protocol for intradermal skin testing in parrots, including recommended site (proventer region), volume of injection (0.02 mL), negative control (saline), positive control (codeine phosphate 1 : 100 000 w/v) and optimum reading time (5 min). Further study to establish appropriate dosages for test antigen will be required.     

Pilot study of echocardiographic studies using color- and pulsed-wave spectral Doppler methods in blue-crowned amazons (Amazona ventralis) and blue-fronted amazons (Amazona a. aestiva)

Colour-flow and pulsed-wave spectral Doppler echocardiography was performed on 6 healthy, adult Hispaniolan amazon parrots (Amazona ventralis) and 6 blue-fronted amazon parrots (Amazona a. aestiva) to establish normal reference values. Birds were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. An electrocardiogram was recorded continuously and birds were imaged with a micro-phased-array scanner with a frequency of 7.0 MHz. After assessment of cardiac function in 2-D-echocardiography, blood flow across the left and the right atrioventricular valve and across the aortic valve was determined using color-flow and pulsed-wave spectral Doppler echocardiography. Diastolic inflow (mean value +/- standard deviation) into the left ventricle was 0.17 +/- 0.02 m/s (Hispaniolan amazons) and 0.18 +/- 0.03 m/s (Blue fronted amazons). Diastolic inflow into the right ventricle was 0.22 +/- 0.05 m/s (Hispaniolan amazons) and 0.22 +/- 0.04 m/s (Blue fronted amazons). Velocity across the aortic valve was 0.84 +/- 0.07 m/s (Hispaniolan amazons) and 0.83 +/- 0.08 m/s (Blue fronted amazons). Systolic pulmonary flow could not be detected in any of the birds in this study. No significant differences were evident between the two species examined. Results of this study indicate that Doppler echocardiography is a promising technique to determine blood flow in the avian heart. Further studies in other avian species are needed to establish reference values for assessment of cardiac function in diseased birds.     

Diffuse intestinal T-cell lymphosarcoma in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata)

A 10-year-old, intact, female yellow-naped Amazon parrot was examined because of anemia, lymphocytic leukocytosis, regurgitation, and weight loss. A positive fecal occult blood and monoclonal globulinopathy were present. A distended proventriculus and diffusely thickened loops of small intestine with irregular luminal surfaces were identified with contrast radiography and contrast computed tomography. A micro positron emission tomography scan was performed with (18)F-fluorodeoxyglucose. Diffuse intestinal T-cell lymphosarcoma was diagnosed based on histopathology and immunohistochemistry of full thickness small intestinal biopsies. The patient was treated with a multidrug chemotherapy protocol with little to no effect. Euthanasia was elected, and intestinal lymphosarcoma was confirmed on histopathology of necropsy intestinal samples; no other organs demonstrated neoplastic infiltration. To the authors' knowledge, no reports are currently available detailing the clinical presentation or diagnosis of diffuse intestinal T-cell lymphosarcoma in any avian species.     

Chronic pulmonary interstitial fibrosis in a blue-fronted Amazon parrot (Amazona aestiva aestiva)

A 30-yr-old blue-fronted Amazon parrot (Amazon aestiva aestiva) was presented to the clinic with a history of sneezing more often during the last 2 mo. Physical examination revealed only a mild nasal discharge. Complete hematologic and plasma biochemical examination showed no abnormalities. Computerized tomography (CT) of the complete bird showed generalized lung alterations consistent with lung fibrosis. Two lung biopsies were taken. The results of the histologic examination of the biopsies confirmed the tentative CT diagnosis of pulmonary interstitial fibrosis. To our knowledge this is the first reported case of chronic pulmonary interstitial fibrosis diagnosed by means of a lung biopsy in an avian species. The histologic characteristics are discussed and compared with those of human idiopathic pulmonary fibrosis.     

A dermoid of the eye in a blue-fronted Amazon parrot (Amazona aestiva)

A corneo-conjunctival dermoid is reported in a blue-fronted Amazon parrot ( Amazona aestiva ). After laminar keratectomy, histology showed the epidermis with feather follicles and dermal connective tissue with lymph follicles and sebaceous glands.     

Effects of bilateral topical administration of repeated doses of rocuronium bromide as a mydriatic agent in Amazon parrots (Amazona aestiva and Amazona amazonica)

The effects of bilateral topical application of repeated doses of rocuronium in parrots are unknown, motivating this research. These effects were evaluated in 24 healthy adult Amazon parrots (12 Amazona aestiva and 12 Amazona amazonica). Three different doses of rocuronium bromide (10 mg/mL) were applied with a micropipette onto the cornea: a single instillation of 20 µL/eye; two instillations of 20 µL/eye, spaced 15 minutes apart; and three instillations of 20 µL/eye, spaced 15 minutes apart. Pupillary diameter (PD) was measured with a digital caliper before treatments (T0), every 15 minutes during the first hour postadministration (T15, T30, T45, T60), hourly for 6 hours (T120, T180, T240, T300, T360), and after 24 hours (T24h). Significant differences were observed between T0 and T15-T120 with a single instillation and between T0 and T15-T360 with double and triple instillations. The maximum median PDs were 3.47 mm (T45—one instillation), 3.88 mm (T45—two instillations), and 4.09 mm (T30—three instillations). PD returned to baseline at T180 with one instillation and at T24h with double and triple instillations. All protocols showed similar PD values at T0 and T24h. Transient lower eyelid paresis was the only adverse effect observed. Bilateral topical administrations of two and three repeated rocuronium bromide doses produced adequate mydriasis in Amazon parrots and may be indicated for longer ophthalmic procedures.     

Palpation‐ and ultrasound‐guided brachial plexus blockade in Hispaniolan Amazon parrots (Amazona ventralis)

ObjectiveTo compare palpation-guided with ultrasound-guided brachial plexus blockade in Hispaniolan Amazon parrots.Study designProspective randomized experimental trial.AnimalsEighteen adult Hispaniolan Amazon parrots (Amazona ventralis) weighing 252–295 g.MethodsAfter induction of anesthesia with isoflurane, parrots received an injection of lidocaine (2 mg kg^?1) in a total volume of 0.3 mL at the axillary region. The birds were randomly assigned to equal groups using either palpation or ultrasound as a guide for the brachial plexus block. Nerve evoked muscle potentials (NEMP) were used to monitor effectiveness of brachial plexus block. The palpation-guided group received the local anesthetic at the space between the pectoral muscle, triceps, and supracoracoideus aticimus muscle, at the insertion of the tendons of the caudal coracobrachial muscle, and the caudal scapulohumeral muscle. For the ultrasound-guided group, the brachial plexus and the adjacent vessels were located with B-mode ultrasonography using a 7–15 MHz linear probe. After location, an 8-5 MHz convex transducer was used to guide injections. General anesthesia was discontinued 20 minutes after lidocaine injection and the birds recovered in a padded cage.ResultsBoth techniques decreased the amplitude of NEMP. Statistically significant differences in NEMP amplitudes, were observed within the ultrasound-guided group at 5, 10, 15, and 20 minutes after injection and within the palpation-guided group at 10, 15, and 20 minutes after injection. There was no statistically significant difference between the two groups. No effect on motor function, muscle relaxation or wing droop was observed after brachial plexus block.Conclusions and clinical relevanceThe onset of the brachial plexus block tended to be faster when ultrasonography was used. Brachial plexus injection can be performed in Hispaniolan Amazon parrots and nerve evoked muscle potentials were useful to monitor the effects on nerve conduction in this avian species. Neither technique produced an effective block at the doses of lidocaine used and further study is necessary to develop a useful block for surgical analgesia.     

Kidney organoid derived from renal tissue stem cells is a useful tool for histopathological assessment of nephrotoxicity in a cisplatin-induced acute renal tubular injury model

Organoids derived from renal tissue stem cells (KS cells) isolated from the S3 segment of adult rat nephrons have previously been developed and evaluated. However, data regarding the histopathological evaluation of these organoids are limited. Therefore, in this study, we performed histopathological examinations of the properties of these organoids and evaluated the nephrotoxicity changes induced by cisplatin treatment. We observe that the tubular structure of the organoids was generally lined by a single layer of cells, in concordance with previous findings. Microvilli were exclusively observed under electron microscopy on the luminal side of this tubular structure. Moreover, the luminal side of the tubular structure was positive for aquaporin-1 (Aqp1), a marker of the proximal renal tubule. Cisplatin treatment induced cell death and degeneration, including cytoplasmic vacuolation, in cells within the tubular structure of the organoids. Cisplatin toxicity is associated with the induction of γ-H2AX (a marker of DNA damage) and the drop of phospho-histone H3 (a marker of cell division) levels. During the nephrotoxicity assessment, the kidney organoids displayed various features similar to those of the natural kidney, suggesting that it is possible to use these organoids in predicting nephrotoxicity. The histological evaluation of the organoids in this study provides insights into the mechanisms underlying nephrotoxicity.