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Biomedical subjects

Lisa A Tell

Publications and source records attributed to Lisa A Tell.

17 recordsLinked to original sources

Comparison of biochemical values in serum and plasma, fresh and frozen plasma, and hemolyzed samples from orange-winged Amazon parrots (Amazona amazonica).

BACKGROUND: To the authors' knowledge, on the basis of sample type, storage condition, or hemolysis, differences in serum and plasma biochemical values have not been evaluated in orange-winged Amazon parrots (Amazona amazonica). OBJECTIVES: The purpose of this study was to compare values for biochemical analytes in serum vs plasma, fresh vs frozen plasma, and nonhemolyzed vs hemolyzed samples in orange-winged Amazon parrots. We also compared differences in serum and plasma yield from whole-blood aliquots. METHODS: Fifteen biochemical analytes were evaluated in paired serum and plasma, fresh and frozen plasma, nonhemolyzed and hemolyzed serum and plasma samples from orange-winged Amazon parrots (n = 10) using a wet reagent analyzer. Hemolysis was assessed qualitatively (visually) and quantitatively (hemoglobin [Hgb] measured spectrophotometrically). Serum and plasma yields from 500-microl whole-blood aliquots were determined from centrifuged samples. RESULTS: Analyte values significantly differed among sample groups, but were still within published reference intervals, with the exception of increases in potassium concentration in markedly hemolyzed serum and plasma samples. Clinically important changes in hemolyzed serum and plasma samples included increases in potassium, phosphorus, and albumin concentrations and lactate dehydrogenase activity. The degree of hemolysis assigned qualitatively did not correlate with quantitative Hgb concentration. A significantly greater yield of plasma (288 +/- 13 microL) than serum (241 +/- 44 microL) was obtained. CONCLUSIONS: Significant differences may occur in different sample types, however, only changes in potassium, phosphorus, albumin, and lactate dehydrogenase values in hemolyzed samples were considered clinically relevant. Lack of agreement between qualitative and quantitative Hgb concentration indicates the unreliability of visual estimation. Based on higher sample yield, and lack of clinically relevant differences from serum, plasma is a better sample choice for clinical chemistry analysis in birds.

Amazona↗

An aerosolized fluorescent microsphere technique for evaluating particle deposition in the avian respiratory tract.

The objective of this study was to examine the feasibility of using aerosolized fluorescent microspheres to examine particle distribution in the respiratory tract of birds following aerosol exposure. Adult domestic pigeons (Columbia livia domestica; n = 5 birds per microsphere size) were exposed to aerosolized monodispersed populations of various sized carboxylate microspheres (0.5, 1.0, 2.0, 3.0, 6.0, and 10.0 microm) for 30 min. For aerosol-exposure purposes, the birds were anesthetized with injectable anesthetics, intubated, and placed on positive-pressure ventilation using a mechanical ventilator. Immediately following aerosol exposure, the birds were euthanatized, and carcasses were preserved via intravenous infusion of modified paraformaldehyde/gluteraldehyde fixative (pH = 7.2 and 340 mOsm). Initial evaluation of microsphere distribution in air sacs (cranial and caudal thoracic and abdominal) and at the level of the ostia was performed using a stereoscopic microscope with an epifluorescent module. More detailed examination of the distribution of microspheres within the respiratory tract was achieved using a confocal scanning laser microscope with a krypton argon laser and a scanning electron microscope. The results from this study revealed that positive-pressure ventilation resulted in distribution of smaller sized fluorescent microspheres (sizes 1.0, 2.0, and 3.0 microm) throughout the pigeon's respiratory tracts, and these microspheres were in highest concentration in the secondary bronchi and ostia for all of the examined air sacs. The larger sized beads (6.0 and 10.0) were confined to the upper airway (trachea and primary bronchi). The results from this study allow for a better understanding of particle deposition following positive-pressure ventilation and aerosol exposure in birds.

Aerosols↗

Evidence for cryptic speciation of Leucocytozoon spp. (Haemosporida, Leucocytozoidae) in diurnal raptors.

Species of Leucocytozoon (Haemosporida, Leucocytozoidae) traditionally have been described based on morphological characters of their blood stages and host cells, with limited information on their avian host specificity. Based on the current taxonomy, Leucocytozoon toddi is the sole valid species of leucocytozoids parasitizing falconiform birds. Using a nested polymerase chain reaction protocol, we determined the prevalence of Leucocytozoon infection in 5 species of diurnal raptors from California. Of 591 birds tested, 177 (29.9%) were infected with Leucocytozoon toddi. Subsequent phylogenetic analysis of the cytochrome b gene revealed that distinct haplotypes are present in hawks of these genera. Haplotypes present in Buteo spp. are not found in Accipiter spp., and there is a 10.9% sequence divergence between the 2 lineage clades. In addition, Leucocytozoon sp. from Accipiter spp. from Europe group more closely with parasites found in Accipiter spp. from California than the same California Accipiter species do with their sympatric Buteo spp. Similarly, a Leucocytozoon haplotype from a Common Buzzard (Buteo buteo) from Kazakhstan forms a monophyletic lineage with a parasite from B. jamaicensis from California. These results suggest that Leucocytozoon toddi is most likely a group of cryptic species, with 1 species infecting Buteo spp. and 1 or more species, or subspecies, infecting Accipiter spp.

Animals↗

Evaluation of the sensitivity and specificity of four laboratory tests for detection of occult blood in cockatiel (Nymphicus hollandicus) excrement.

OBJECTIVE: To compare sensitivity and specificity of cytologic examination and 3 chromogen tests for detection of occult blood in cockatiel (Nymphicus hollandicus) excrement. ANIMALS: 20 adult cockatiels. PROCEDURES: Pooled blood from birds was divided into whole blood and lysate aliquots. Excrement was mixed with each aliquot in vitro to yield 6 hemoglobin (Hb) concentrations (range, 0.375 to 12.0 mg of Hb/g of excrement). For the in vivo portion of the study, birds were serially gavaged with each aliquot separately at 5 doses of Hb (range, 2.5 to 40 mg/kg). Three chromogen tests and cytologic examination were used to test excrement samples for occult blood. Sensitivity, specificity, and observer agreement were calculated. RESULTS: In vitro specificity ranged from 85%to 100% for the 3 chromogen tests and was 100% for cytologic examination. Sensitivity was 0% to 35% for cytologic examination and 100% for the 3 chromogen tests on samples containing >or= 1.5 mg of Hb/g of excrement. In vivo specificity was 100%, 90%, 65%, and 45% for cytologic examination and the 3 chromogen tests, respectively. Sensitivity was 0% to 5% for cytologic examination and >or= 75% for all 3 chromogen tests after birds received doses of Hb >or= 20 mg/kg. Observer agreement was lowest for cytologic examination. CONCLUSIONS AND CLINICAL RELEVANCE: Chromogen tests were more useful than cytologic examination for detection of occult blood in cockatiel excrement. The best combination of sensitivity, specificity, and observer agreement was obtained by use of a chromogen test.

Animals↗

Cutaneous vascular malformation in a guinea pig (Cavia porcellus).

A skin lesion classified as a vascular malformation is reported in a young-adult, female guinea pig. The physical examination revealed a 3 x 2-cm irregularly shaped violaceous plaque located on the left caudal flank. The surface of the plaque was ulcerated and bled intermittently, resulting in fatal blood loss. On histology the mass consisted of variably sized vascular spaces filled with red blood cells and variable amounts of extramedullary haematopoietic cells, lined by well-differentiated endothelial cells often surrounded by one layer of spindle-shaped cells. Based on immunohistochemistry, the spindle cell population was confirmed to be smooth muscle cells and no proliferation of endothelial cells was found with the Ki67 proliferation marker. Histological and immunohistochemical findings were consistent with a vascular malformation. Classification of vascular malformations and potential treatments are discussed. To the authors' knowledge, this is the first reported case of a cutaneous vascular lesion in a guinea pig.

Animals↗

Assessment of a caudal external thoracic artery axial pattern flap for treatment of sternal cutaneous wounds in birds.

OBJECTIVE: To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds. ANIMALS: 16 adult Japanese quail. PROCEDURE: A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability. RESULTS: All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat self-mutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species.

Animals↗

Adult cockatiels (Nymphicus hollandicus) at maintenance are more sensitive to diets containing excess vitamin A than to vitamin A-deficient diets.

The purpose of this experiment was to examine the physiological responses of adult cockatiels at maintenance to dietary vitamin A (VA) concentrations, and to identify concentrations associated with deficiency and toxicity. Adult cockatiels at maintenance (n = 22, 2-3 y of age) were fed a diet of 0, 600, 3000 or 30,000 microg VA/kg (0, 2000, 10,000 or 100,000 IU), and monitored for signs of VA deficiency or toxicity for up to 706 d. The analyzed diet concentrations were 0, 835, 2815 and 24,549 microg/kg, respectively. After 269 d, birds fed the 30,000 microg/kg VA diet had greater plasma retinal concentrations, markedly intensified vocalization patterns, pancreatitis and multifocal accumulation of lymphocytes in the lamina propria of the duodenum compared to birds fed the 600 microg/kg diet (P < 0.05). The 3000 microg/kg VA diet induced increased plasma retinol, splenic hemosiderosis and altered vocalization patterns (P < 0.05), although not as striking as those induced by the 30,000 microg/kg VA diet. The secondary antibody response was reduced after 225 d and vocalization patterns were altered in birds fed 0 microg/kg VA (P < 0.05), but after almost 2 y there were no changes in body condition, plasma retinol, organ pathology or classical signs of deficiency such as squamous metaplasia of nasal epithelia. Thus, adult cockatiels at maintenance were more susceptible to VA toxicity than to VA deficiency and concentrations > or = 3000 microg VA/kg diet can cause toxicity. It is possible that disturbances in VA nutrition contribute to the widespread incidence of behavioral problems reported in companion birds.

Animals↗

Pharmacokinetics of ceftiofur sodium after intramuscular or subcutaneous administration in green iguanas (Iguana iguana).

OBJECTIVE: To determine the pharmacokinetics of ceftiofur sodium after IM and SC administration in green iguanas. ANIMALS: 6 male and 4 female adult green iguanas. PROCEDURE: In a crossover design, 5 iguanas received a single dose of ceftiofur sodium (5 mg/kg) IM, and 5 iguanas received the same dose SC. Blood samples were taken at 0, 20, and 40 minutes and 1, 2, 4, 8, 24, 48, and 72 hours after administration. After a 10-week washout period, each iguana was given the same dose via the reciprocal administration route, and blood was collected in the same fashion. Ceftiofur free-acid equivalents were measured via high-performance liquid chromatography. RESULTS: The first phase intercepts were significantly different between the 2 administration routes. Mean maximum plasma concentration was significantly higher with the IM (28.6 +/- 8.0 microg/mL) than the SC (18.6 +/- 8.3 microg/mL) administration route. There were no significant differences between terminal half-lives (harmonic mean via IM route, 15.7 +/- 4.7 hours; harmonic mean via SC route, 19.7 +/- 6.7 hours) and mean areas under the curve measured to the last time point (IM route, 11,722 +/- 7,907 microg x h/mL; SC route, 12,143 +/- 9,633 microg x h/mL). Ceftiofur free-acid equivalent concentrations were maintained > or = 2 microg/mL for > 24 hours via both routes. CONCLUSIONS AND CLINICAL RELEVANCE: A suggested dosing schedule for ceftiofur sodium in green iguanas for microbes susceptible at > 2 microg/mL would be 5 mg/kg, IM or SC, every 24 hours.

Animals↗

Pharmacokinetics and anesthetic and cardiopulmonary effects of propofol in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

OBJECTIVE: To determine induction doses, anesthetic constant rate infusions (CRI), and cardiopulmonary effects of propofol in red-tailed hawks and great horned owls and propofol pharmacokinetics in the owls during CRI. ANIMALS: 6 red-tailed hawks and 6 great horned owls. PROCEDURE: The CRI dose necessary for a loss of withdrawal reflex was determined via specific stimuli. Anesthesia was induced by IV administration of propofol (1 mg/kg/min) and maintained by CRI at the predetermined dose for 30 minutes. Heart and respiratory rates, arterial blood pressures, and blood gas tensions were obtained in awake birds and at various times after induction. End-tidal CO2 (ETCO2) concentration and esophageal temperature were obtained after induction. Propofol plasma concentrations were obtained after induction and after completion of the CRI in the owls. Recovery times were recorded. RESULTS: Mean +/- SD doses for induction and CRI were 4.48 +/- 1.09 mg/kg and 0.48 +/- 0.06 mg/kg/min, respectively, for hawks and 3.36 +/- 0.71 mg/kg and 0.56 +/- 0.15 mg/kg/min, respectively, for owls. Significant increases in PaCO2, HCO3, and ETCO2 in hawks and owls and significant decreases in arterial pH in hawks were detected. A 2-compartment model best described the owl pharmacodynamic data. Recovery times after infusion were prolonged and varied widely. Central nervous system excitatory signs were observed during recovery. CONCLUSIONS AND CLINICAL RELEVANCE: Effects on blood pressure were minimal, but effective ventilation was reduced, suggesting the need for careful monitoring during anesthesia. Prolonged recovery periods with moderate-to-severe excitatory CNS signs may occur in these species at these doses.

Anesthesia↗

Hematologic values for tule elk (Cervus elaphus nannodes).

Hematologic values for 99 tule elk (Cervus elaphus nannodes) from California (USA) are presented. These were obtained from individuals from three captures at Tomales Point (Point Reyes National Seashore, California) from 1997-98. Differences between capture groups were assessed. Greatest differences were detected between yearling bulls and cows in December 1998 which may be a reflection of age and reproductive status.

Animals↗

Management of an ingested lead foreign body in an Amazon parrot.

An adult male, double-yellow-head Amazon parrot (Amazona ochrocephala oratrix) was presented with a 36-h history of seizure episodes. On presentation, the bird was slightly obtunded, seizured once for approximately 20 sec and the seizure was controlled with midazolam. Whole body radiographs revealed a 2-mm diameter, circular, dense object in the ventriculus. A presumptive diagnosis was made of lead toxicosis, and supportive care of sc fluids and gavage feedings. Calcium disodium EDTA and chelation therapy was initiated immediately. Blood analysis revealed 1.2 ppm lead wet weight. Bulk diet therapy with freQuent high fiber gavage feedings was unsuccessful at removing the foreign body and the lead object was ultimately retrieved from theventriculus using endoscopy. Sources of lead available to the pet birds include lead weights, solder, stained glass molding, jewelry and bird toys. However, this Amazon parrot was fed portions of game birds that contained lead shots within their muscles, which is a common source of secondary lead poisoning in raptors.

Animals↗

Taenia coenurus in the orbit of a chinchilla.

A 4-year old, male intact, captive-bred chinchilla (Chinchilla lanigera) was presented due to progressive exophthalmos of the right eye over a 5-month period. Ophthalmic examination revealed exophthalmos with dorsal displacement of the right globe. Retropulsion was decreased and a fluctuant, subcutaneous mass could be palpated posterior and dorsal to the central aspect of the zygomatic bone. Transdermal ultrasonography revealed a fluid-filled mass consistent with a cyst located within the ventral right orbit. Computed tomography demonstrated dorsal displacement of the globe, lateral displacement of the zygomatic arch, and numerous mineral-dense foci within the lumen of the cyst. The cyst was removed en bloc by ventral transpalpebral orbitotomy. Histopathology revealed a single capsulated cyst with multiple invaginated protoscolices, characterized by a prominent scolex with refractile hooklets, suckers, and abundant calcareous corpuscles consistent with a Taenia coenurus. Exophthalmos resolved with surgical therapy and there was no evidence of recurrence or postoperative complications over a period of 2 years. To the authors' knowledge, this is the first reported case of an orbital cyst of parasitic origin in a chinchilla.

Animals↗

Internal papillomatosis with intrahepatic cholangiocarcinoma and gastrointestinal adenocarcinoma in a peach-fronted conure (Aratinga aurea).

A 17-yr-old pet female peach-fronted conure (Aratinga aurea) was presented with the chief complaints of mild lethargy and weight loss with increased appetite. Antemortem diagnostics included complete blood count, plasma biochemistry, and radiography. Abnormal findings included elevated inflammatory parameters (hyperfibrinogenemia) and a space-occupying mass in the region of the liver. Histologic examination of a liver biopsy sample indicated bile duct hyperplasia leading to a presumptive diagnosis of hepatoxicosis. The bird initially showed moderate improvement with supportive care, but its condition declined 9 days after the liver biopsy. Supportive care was attempted a second time, but the bird did not improve and euthanasia was elected. Abnormal gross necropsy findings were confined to the liver, which contained multiple tan nodules that exuded yellowish fluid on cut section. Histopathologic examination revealed multicentric bile duct hyperplasia and cholangiocarcinoma as well as segmental papillary hyperplasia and adenocarcinoma in the proventriculus, ventriculus, and throughout the intestinal tract. This is the first report of concurrent internal papillomatosis, gastrointestinal adenocarcinoma, and cholangiocarcinoma in a peach-fronted conure.

Adenocarcinoma↗

A model of avian mycobacteriosis: clinical and histopathologic findings in Japanese quail (Coturnix coturnix japonica) intravenously inoculated with Mycobacterium avium.

Mycobacterial infections are an important cause of morbidity and mortality in birds and a considerable diagnostic challenge until the disease is advanced. In order to develop more clinically useful antemortem tests, a biological model was created that replicated naturally occurring disease. Japanese quail (Coturnix coturnix japonica; n = 8) were inoculated intravenously with Mycobacterium avium. Two additional birds served as uninoculated controls. Mean survival time of the inoculated birds was 68 +/- 13 days postinoculation (PI). Seven of the eight inoculated birds died naturally. Clinical and postmortem abnormalities in inoculated birds were characteristic of naturally occurring mycobacteriosis. Abnormal clinical findings included decreased activity, feather erection, and sudden death. Mean body weight and packed cell volume declined and mean total white blood cells (primarily heterophils, bands, and monocytes) increased from 28 days PI onward. Similar to birds that are naturally infected with mycobacteriosis, the inoculated birds were thin and had severe hepatosplenomegaly on postmortem examination. All eight birds had lesions in the liver, spleen, intestine, lung, gonads, and serosa. Less commonly affected tissues included bone marrow, thymus, gizzard, heart, pancreas, and brain. Lesions were invariably severe in the liver and spleen. These gross postmortem findings were consistent with natural infections of avian mycobacteriosis. Mycobacterium avium was isolated from the liver, spleen, and intestine of all inoculated birds. Both control birds remained disease free and culture negative. This inoculation protocol is a reliable and practical means of inducing avian mycobacteriosis for further study.

Animals↗

Diagnosis of avian mycobacteriosis: comparison of culture, acid-fast stains, and polymerase chain reaction for the identification of Mycobacterium avium in experimentally inoculated Japanese quail (Coturnix coturnix japonica).

In this study we compared culture, acid-fast stains, and polymerase chain reaction (PCR) for the detection of acid-fast organisms in fecal and tissue samples from Japanese quail (Coturnix coturnix japonica) that were experimentally inoculated intravenously with Mycobacterium avium. For culture, three different culture media (modified Herrold egg yolk with mycobactin; Lowenstein-Jensen [L-J]; and L-J with cyclohexamide, naladixic acid, and lincomycin) were tested to determine which medium had the greatest success in isolating mycobacteria. Acid-fast staining methods included Zichl-Neelsen (Z-N) and Truant. The PCR assay detected mycobacterial DNA with primers specific for the 65-kD heat shock protein gene. Culture was considered the "gold standard." Compared with other culture media, L-J yielded more positive cultures and greater numbers of colonies on positive tubes, and incubation times were shorter. Mycobacterium avium was isolated from all of the harvested tissue samples (liver, spleen, and intestine) of inoculated birds. Mycobacteria were isolated from 53% (69/130) of fecal samples from inoculated birds. As the disease advanced, fecal culture was positive on more culture days, indicating that the culture-positive rate was higher later in the course of the disease. Compared with culture, all of the laboratory methods had 100% specificity for the tissue samples. Sensitivities for the tissue samples were 82.6% (Z-N), 95.7% (Truant), and 100% (PCR). For the fecal samples, the specificity was >95% for all methods. Sensitivities compared with fecal culture were 7.2% (Z-N), 30.4% (Truant), and 20.3% (PCR). Tissue and fecal samples from the two control birds were negative for acid-fast organisms by any method. These results were comparable with clinical cases of avian mycobacteriosis where culture and PCR of tissue samples seem to be the most sensitive and specific laboratory tests and evaluation of fecal samples still remains challenging. On the basis of the results of this study, identification of mycobacteria in fecal samples from Japanese quail can be optimized by repeated cultures and Truant acid-fast staining of fecal smears.

Animals↗

Real-time polymerase chain reaction testing for the detection of Mycobacterium genavense and Mycobacterium avium complex species in avian samples.

Diagnosis of avian mycobacteriosis, caused by Mycobacterium genavense or species belonging to the Mycobacterium avium complex (MAC), is problematic. Polymerase chain reaction (PCR) offers rapid and sensitive detection of minute quantities of DNA, and conventional protocols have been used for evaluating avian specimens. The recent development of real-time PCR offers several advantages over conventional PCR. In attempts to improve diagnosing avian mycobacteriosis, a real-time TaqMan PCR assay was developed targeting the 65-kD heat shock protein gene of M. genavense and MAC spp. Nineteen reference isolates, 16 clinical isolates, and 32 avian tissue samples were used to evaluate the assay. When sufficient amplicons were produced, the species of mycobacteria was determined by standard sequencing of TaqMan PCR products and compared with results from commercial mycobacteriology laboratories and/or standard sequencing of conventional PCR products. The TaqMan PCR detected DNA from reference isolates of M. genavense, MAC spp., and Mycobacterium tuberculosis complex spp. Of the clinical isolates, the TaqMan PCR detected DNA from 10 of 12 Mycobacterium avium avium isolates and two of three Mycobacterium avium intracellulare isolates. For the tissue samples, the TaqMan PCR amplified DNA in six of nine samples that were identified by sequencing of conventional PCR products and/or by commercial mycobacteriology laboratories as being MAC spp. positive and three of four samples that were positive for M. genavense. There was some disagreement between speciation results from the TaqMan PCR and those from commercial mycobacteriology laboratories or conventional PCR or both. This disagreement was suspected to be because of relatively small numbers of base pairs in the TaqMan PCR products. The TaqMan PCR may provide a useful tool for evaluating clinical samples for DNA from mycobacteria species that most commonly infect birds; however, further refinement is needed in order to improve sensitivity and provide more accurate speciation.

Base Sequence↗

Comparison of four rapid DNA extraction techniques for conventional polymerase chain reaction testing of three Mycobacterium spp. that affect birds.

Mycobacteriosis is an avian disease that is most commonly caused by Mycobacterium avium or Mycobacterium genavense. In order to optimize molecular laboratory tests for diagnosing mycobacteriosis in birds, we compared four methods of rapid DNA extraction with isolates of M. avium, M. genavense, and Mycobacterium fortuitum. DNA extraction methods included enzymatic lysis, boiling for 30 min followed by enzymatic lysis, four cycles of freezing and thawing followed by enzymatic lysis, and bead beating followed by enzymatic lysis. The DNA yield and purity for the four methods were evaluated by spectrophotometry and compared. The bead beating with enzymatic lysis technique yielded significantly purer and higher concentrations of extracted DNA compared with other DNA extraction methods. All four methods yielded extraction products for all three organisms that were successfully amplified by polymerase chain reaction (PCR) for a fragment in the 65-kD heat shock protein gene. Subjectively, the PCR amplification products were most abundant for samples extracted by bead beating with enzymatic lysis.

Animals↗