Thyroid cystadenoma, colloid goiter, and hypothyroidism in an American black bear (Ursus americanus).

A 178-kg, 14-yr-old captive female American black bear (Ursus americanus) was examined because of lethargy, inappetance, obesity, and alopecia. Serum chemistry and complete blood count values were within normal limits. Based on serum levels for total thyroxine (T4), free T4 by equilibrium dialysis (fT4ED), and canine thyroid-stimulating hormone concentrations, using assays validated for domestic dogs, hypothyroidism was diagnosed presumptively, and therapy with levothyroxine sodium (0.022 mg/kg p.o. b.i.d.) was initiated. Haircoat, body weight, appetite, and activity level improved within 30 days. The levothyroxine dose was decreased twice (to 0.018 mg/kg p.o. b.i.d. and then to 0.011 mg/kg p.o. b.i.d.) during the course of treatment based on monitoring of serum T4 and fT4ED concentrations. After euthanasia for severe refractory lameness, postmortem examination revealed bilateral thyroid lobe enlargement and a fluid-filled cyst within the right lobe. Histologically, colloid goiter was present in both lobes, and a follicular cystadenoma had replaced one third of the cranial pole of the right lobe. The goiter and cystadenoma likely contributed to the hypothyroid condition in this bear and fT4ED was a more sensitive indicator of hypothyroidism than was T4. The recommended canine dosage of levothyroxine may be too high for the treatment of hypothyroidism in American black bears; 0.011 mg/kg p.o. b.i.d. may be a more appropriate dosage.     

Ultrasonographic study of ovarian activities in the tropical jenny during the seasons of high and low sexual activity

The ovarian activities of 7 jennies were studied by serial ultrasonography during seasons of higher and lower sexual activity to determine if follicular development also corresponds to this pattern. The current study showed a seasonal pattern of ovarian activities related to the local environmental factors associated with each season rather than photoperiod, which is the widely known environmental cue determining seasonality in most equines. Jennies produced large numbers of follicles (11.3 follicles) during the long rainy season, compared with the 7.3 and 9.6 follicles during the dry and short rainy seasons, respectively. However, production of larger preovulatory follicles (37.8 ± 1.7 mm vs 31.0 ± 2.7 mm of the dry and 33.2 ± 2.7 mm of the long rainy seasons) and higher incidence of ovulation (77.8%) occurred during the short rainy season. Jennies had shorter interovulatory intervals during the season of higher (short rainy) than the season of lower (dry season) sexual activity. The short rain transition is characterized by higher follicular activity compared with the long rainy transition, indicating the presence of additional factors stimulating ovarian activity other than the mere availability of forage during the short rainy season.     

Extraventricular neurocytoma of the spinal cord in a dog

Central neurocytoma is a rare, prognostically favorable neuronal tumor of the human central nervous system, typically located intraventricularly near the foramen of Monro. Extraventricular cerebral neurocytomas and spinal tumors have also been reported. To date, however, neurocytomas have not been documented in domestic animal species. In this report, we describe a spinal cord tumor in a dog. The microscopic examination revealed tumor cells forming loosely packed clusters in some areas and palisades in other areas. In addition, they showed fine fibrillary neuropil-like areas of different sizes, sometimes resembling the "rosettes" of pineocytomas, as well as ependymoma-like perivascular pseudorosettes. The tumor cells had scant eosinophilic cytoplasm, with perinuclear halos, closely resembling the appearance of oligodendroglioma. Immunohistochemical staining showed expression of synaptophysin and neuron-specific enolase by tumor cells and pronounced in fibrillary areas. On the basis of histomorphology and immunohistochemical reactivity, the present tumor was diagnosed as extraventricular neurocytoma.     

Evaluation of canine lymphocyte proliferation: comparison of three different colorimetric methods with the 3H-thymidine incorporation assay.

To evaluate canine lymphocyte stimulation the radioactive thymidine incorporation assay is still the method of choice. In order to find a suitable non-radioactive alternative to the standard 3H-thymidine incorporation assay, proliferation of canine peripheral blood lymphocytes (PBL) was measured with three different colorimetric assays, using the two tetrazolium salts MTT and XTT and 5-bromo-deoxyuridine (BrdU). Isolated canine PBL were stimulated with two different mitogens, Concanavalin A (Con A) and Phytohemagglutinin (PHA), using different culture conditions. Applying statistical analysis we found that BrdU and MTT showed a high correlation to the 3H-thymidine incorporation assay, although the BrdU assay proved to be more sensitive than the MTT assay. No significant correlation between the XTT assay and the radioactive method was demonstrated. Consequently, the BrdU assay is the most suitable alternative to the radioactive method.     

A spatially explicit approach to prioritize protection areas for endangered freshwater mussels

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Taxonomic and geographical representation of freshwater environmental DNA research in aquatic conservation

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The importance of stream interstitial conditions for the early‐life‐stage development of the European nase (Chondrostoma nasus L.)

Rheophilic cyprinid populations are in decline in many European rivers and have become target species of conservation and river restoration. This is especially true for the European nase (Chondrostoma nasus), a lithophilic species for which the early life stages pose the first bottlenecks in successful population development. In this study, egg dispersal at the substrate surface as well as within the stream interstitial was evaluated and the development of nase eggs was tested at three spawning grounds in the German Alpine Foreland. New incubation systems for cyprinid eggs as well as reference incubation boxes were developed. A significantly higher number of nase eggs (95.5%) were deposited within the stream interstitial compared to eggs sticking to the substrate surface (4.5%). Most eggs successfully developed within the stream interstitial, and hatched larvae moved deeper into the stream substrate. Higher fine sediment accumulation rates in incubation systems had a negative impact on hatching rates. Our results suggest that a permeable, well‐oxygenated stream interstitial at spawning grounds can greatly enhance hatching rates and successful development of nase, as previously found for other taxa such as salmonids. Furthermore, movements of hatched larvae into deeper layers of the stream interstitial underline its importance not only for egg development, but also as shelter for early life stages. Future conservation and restoration efforts should thus consider more intensively stream interstitial conditions on spawning grounds, including evaluating physical characteristics, fine sediment accumulation as well as bioindication with suitable incubation systems for cyprinids.     

The effects of a probiotic on blood urea nitrogen and creatinine concentrations in large felids

Chronic kidney disease is a common finding in older captive exotic felids. The purpose of this study was to evaluate the effectiveness of a probiotic to reduce blood urea nitrogen and creatinine in large felids. Fifteen adult, large felids (6 tigers [Panthera tigris], 5 lions [Panthera leo], 3 cougars [Puma concolor], and 1 leopard [Panthera pardus]) were administered a probiotic twice daily after a baseline complete blood cell count and plasma chemistry panel was obtained. Plasma chemistry values were rechecked at 2 mo (n = 14) and 6 mo (n = 9). There was no significant change in blood urea nitrogen over time; however, there was a significant change in creatinine over time (P = 0.04). Creatinine concentration decreased significantly between 2 and 6 mo (P = 0.02), and a decrease was seen between 0 and 6 mo, but this change was not significant (P = 0.05). There was no significant difference noted for creatinine concentration between 0 and 2 mo (P = 0.35). This probiotic may be helpful in large felids with elevated creatinine concentrations because of chronic kidney disease; however, further studies are warranted.