Echocardiographic effects of dexmedetomidine-ketamine in chinchillas ( Chinchilla lanigera).

Alpha2-agonist anesthetic combinations are often used in rodent anesthesia but no information about their effects on cardiac function in chinchillas exists. The purpose of this study was to utilize echocardiography to evaluate the cardiovascular effects of dexmedetomidine-ketamine anesthesia in chinchillas. Echocardiographic examinations were performed in eight adult chinchillas under manual restraint and following dexmedetomidine (0.015 mg/kg) and ketamine (4 mg/kg) administration. Dexmedetomidine-ketamine anesthesia resulted in a significantly decreased heart rate, fractional shortening, cardiac output, and flow velocity across the aortic and pulmonic valves, and significantly increased left ventricular internal diameter in systole. The observed changes in echocardiographic parameters are similar to those previously reported in chinchillas anesthetized with isoflurane.

Haematology, blood chemistry and urine parameters of free-ranging plains viscachas (Lagostomus maximus) in Argentina determined by use of a portable blood analyser (i-STAT) and conventional laboratory methods.

Haematology, blood chemistry and urine values were determined for 44 adult free-ranging plains viscachas (Lagostomus maximus; Rodentia, Chinchillidae) in their pampas habitat in central Argentina. The study animals were captured in the wild and anaesthetized with a ketamine-xylazine combination for physical examination and sampling. Blood was obtained by venipuncture of the saphenous vein. Results for many of the blood parameters fall within the reference ranges for pet chinchillas. Differentiation of white blood cells revealed a predominantly neutrophil count for plains viscachas, while chinchillas have predominantly lymphocytes. Mean values for blood urea nitrogen, creatinine, aspartate aminotransferase and sodium were higher than the upper limit of the reference range for pet chinchillas. The results of seven analytes (haematocrit, haemoglobin, glucose, blood urea nitrogen, sodium, potassium, chloride) were compared by using both a portable blood analyser (i-STAT) in the field and conventional laboratory methods. In general, correlation and agreement between the two methods were low for most parameters.

Thyroparathyroidectomy procedures and thyroxine levels in the chinchilla.

Thyroid and embedded parathyroid glands were surgically removed (thyroparathyroidectomized) from adult chinchillas (Chinchilla laniger) to create an animal model of hypothyroidism. Thyroxine (T4) levels were measured at the time of surgery and one or two times after surgery from 10 thyroparathyroidectomized chinchillas and five sham controls to establish baseline serum T4 levels and to assess the degree and duration of hypothyroidism in this animal model. Baseline T4 levels ranged from 3.4 to 6.4 microg/dl (mean +/- 1 standard deviation, 5.25 +/- 0.84 microg/dl), with no differences between male and female chinchillas (5.4 +/- 0.6 microg/dl versus 5.2 +/- 1.0 microg/dl, respectively). T4 levels were significantly reduced in 80% of thyroparathyroidectomized chinchillas when measured 6 to 14 days after surgery, but reductions were variable, ranging from 9 to 89% in individual animals. There was rapid regrowth of thyroid tissue and a return of T4 levels to the baseline range in five of the seven animals followed for 1 to 2 months after surgery. T4 levels increased significantly in the sham-operated chinchillas, indicating a nonspecific effect of surgery. The results establish surgical procedures for creating a model of variable, transient hypothyroidism in the chinchilla. We also summarize published basal T4 values for various laboratory animals, to provide a convenient reference.

Hemoglobin affinity in Andean rodents.

Blood hemoglobin oxygen affinity (P50) was measured in three Andean species and in the laboratory rat (control), all raised near sea level. Chinchilla lanigera (Molina, 1792) has an altitudinal habitat range from low Andean slopes up to 3000 m., while Chinchilla brevicaudata (Waterhouse, 1848) has an altitudinal range from 3000 to 5000 m. The laboratory type guinea pig, wild type guinea pig (Cavia porcellus), (Waterhouse, 1748), and laboratory rat (Rattus norvegicus) were also raised at sea level. The Andean species had high hemoglobin oxygen affinities (low P50) compared with the rat. Chinchilla brevicaudata had a higher affinity than Chinchilla lanigera. The wild type guinea pig had a higher affinity than the laboratory type. As has been shown in other species, this is another example of an inverse correlation between the altitude level and the P50 values. This is the first hemoglobin oxygen affinity study in Chinchilla brevicaudata.

Clinical pathology and sample collection of exotic small mammals.

The clinical pathology of some of the less common and newly emerging small mammal species is detailed in this article. The species covered here include the chinchilla, prairie dog, African hedgehog, and sugar glider. Venipuncture sites and sampling techniques are discussed in general and for each species. Detailed information on the hematology and serum biochemistry values of these animals is presented in numerous tables. Specific information is also provided for urinalysis, fecal analysis, dermatologic sampling, and cytology.

Twenty-four hour changes in lysozyme levels, total plasma protein concentration, gamma-globulin concentration, white blood cell count and numbers of lymphocytes and granulocytes in the peripheral blood of chinchillas Chinchilla laniger M. and rabbits Oryctolagus cuniculus L.

Twenty-four hour changes in lysozyme level, total plasma protein concentration, gamma-globulin concentration, leucocyte number and different forms of leucocyte in the peripheral blood of male chinchillas and rabbits were investigated. All investigated parameters in both species showed statistically significant 24-hr changes, but only total plasma protein concentration in rabbits and gamma-globulin concentration and leucocyte number in chinchillas have a circadian rhythm character. The cosine curve characteristics for these rhythms are as follows; acrophases 0.45 + 2.18 hr, 10.02 + 4.29 hr, 2.14 + 3.20 hr; amplitudes 0.48 + 0.32 g%, 0.34 + 0.41 g%, 1.12 + 0.88 X 10(3)/min3; mesors 6.10 + 0.22 g%, 2.23 + 0.21 g%, 8.78 + 0.65 X 10(3)/mm3, respectively.

Seasonal fluctuations in plasma protein fraction levels of chinchillas (Chinchilla laniger, M.).

Seasonal changes in blood plasma protein fractions in chinchilla females and males were found. Plasma albumin levels in both sexes vary according to season, generally low in winter and spring and high in summer and autumn. The levels of alpha 1-globulin and gamma-globulin increase markedly in spring (1.5 times higher than in winter and autumn). In chinchilla females, the levels of alpha 2-globulin and beta 2-globulin varied biphasically, being higher in winter and summer. In males, clear seasonal trends in the levels of both fractions were not observed. The beta 1-globulin fraction levels vary throughout the year. In females as well as males, globulin decreases during winter to minimal values in late spring, and then increases again during the summer to remain at the same level till autumn.

Peripheral plasma progesterone concentration and haematological indices during normal pregnancy of chinchillas (Chinchilla laniger, M.).

Peripheral plasma progesterone concentration and some haematological indices in pregnant chinchillas were studied. As pregnancy advanced progesterone concentration showed a marked change from high values in early pregnancy (days 9-29), to undetectable values by days 40-60, and from high values in the latter states of pregnancy (days 70-80), to very low values during the 30 days before parturition. Haematocrit value and mean erythrocyte volume change inversely to progesterone concentration fluctuations. White blood cell parameters increased during the first half of pregnancy, then decreased to the lowest level before parturition.

Seasonal changes in the haematological indices in peripheral blood of chinchilla (Chinchilla laniger L.).

Changes in nine haematological indices in adult female and male chinchilla were investigated over a period of 18 months. All haematological values were in the same range both for females and males, although seasonal fluctuations were more evident in the females. High levels of the red blood cells count (RBC), haemoglobin concentration (Hb), mean cell haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) during the winter months and low levels of these parameters during the summer months were found. The white blood cells count (WBC) and lymphocyte number (L) also decreased in summer, their values increasing during autumn and spring. The haematocrit values (Ht) and mean cell volumes (MCV) are high during the summer and low during the winter.

Adaptation of the orbital sinus bleeding technique to the chinchilla (Chinchilla laniger).

The orbital sinus bleeding technique was used to obtain 1-3 ml samples of venous blood from chinchillas (Chinchilla laniger) within 1 minute. By monitoring food intake and body weight, this technique was shown to have no detrimental effects on the general health of the animals, but serial samples taken twice weekly over a period of 2 months did induce some degree of hemorrhage or occasional corneal opacity in some animals.