Mammary lipid-rich carcinoma with extensive amyloid deposition in a dog

A 6-year-old female Labrador retriever presented with a mass in the right mammary gland, and swollen right inguinal and axillary lymph nodes. Fine needle aspiration biopsy suggested a malignant lipid-producing tumor, such as liposarcoma. Histopathologically, the neoplasms were solid, lobulated nests of atypical epithelial cells with a large amount of extracellular deposits of amyloid in both mammary gland and lymph nodes. The proliferating cells contained large cytoplasmic vacuoles, positive for oil red-O. These cells were immunopositive for cytokeratin (AE1/AE3) and β-casein and negative for SMA. The amyloid deposits were immunopositive for β-casein. These findings suggested that the proliferating cells secreted β-casein forming amyloid deposits. This is the first report of mammary lipid-rich carcinoma with extensive amyloid deposition derived from β-casein.     

Seasonal changes in spermatogenesis and peripheral testosterone concentration in raccoons (Procyon lotor) in Hokkaido

Feral raccoons (Procyon lotor) have been increasing in number since 1979 and are currently subject to pest control in Hokkaido. One of the reasons for the increase in numbers is thought to be the high reproductive potential of raccoons, but little is known about their reproduction. The main aim of this study was to clarify seasonal changes in spermatogenesis and peripheral testosterone concentration of raccoons in Hokkaido. In the present study, external characteristics and histology of the testis and epididymis and the plasma testosterone concentration were investigated in 68 feral, male raccoons culled for pest control and once a month in one live, captive male. The feral males exhibited seasonal changes in spermatogenesis, showing active spermatogenesis in autumn, winter and spring (October-June) with noted spermatogenesis and inactive spermatogenesis in summer (July-September) with lower mean levels of spermatozoa in the cauda epididymis. Even in the inactive period, spermatozoa were observed in about half of the individuals (14/26); therefore, individuals producing spermatozoa existed every month throughout the year. Testosterone concentrations were significantly high in the winter mating season. In the captive male, the testosterone concentrations were low from June to August, and spermatozoa could not be observed from July to September. These results suggest that raccoons exhibit seasonality of reproduction, but the time and duration of spermatogenetic decline varies widely among individuals. This individual variation in the inactive period is a feature of male raccoon reproduction and is unique among seasonally breeding mammals.     

Chemical restraint by medetomidine and medetomidine–midazolam and its reversal by atipamezole in Japanese macaques (Macaca fuscata)

Objective To evaluate the sedative effects of medetomidine, and a medetomidine–midazolam combination, in Japanese macaques and the antagonism of medetomidine–midazolam with atipamezole. Study design Prospective randomized study. Animals Thirteen healthy Japanese macaques between 3 and 21 years old and weighing between 4.3 and 15.1 kg. Methods Medetomidine (120 µg kg^?1) alone or a medetomidine (30 µg kg^?1) plus midazolam (0.3 mg kg^?1) mixture were injected intramuscularly in the hind limb of 12 animals (n = 6 for each group) and their effects, particularly behavioural changes, response to external stimuli, sedative onset time, time to lateral recumbency and time in lateral recumbency, were monitored for 120 minutes. Another group (n = 7) were given medetomidine–midazolam and injected 30 minutes later with atipamezole (120 µg kg^?1). Behavioural changes and responses to external stimuli were assessed as before. Results Animals given medetomidine became sedated but could be aroused by external stimuli. Despite the lower (25%) dose of medetomidine involved, the effects of medetomidine–midazolam were more marked. Macaques given this combination became sedated in 4 ± 2 minutes (mean ± SD) and remained unresponsive to external stimuli for at least 60 minutes. Five out of six macaques became laterally recumbent for 74 ± 37 minutes. Intramuscular atipamezole effectively reversed sedation, shortening the arousal and total recovery time. The recovery from sedation was rapid and smooth, being completed 19 ± 11 minutes after antagonism. Conclusions The medetomidine–midazolam combination described provided useful chemical restraint and may prove useful in macaques undergoing some experimental, diagnostic or therapeutic procedures. The use of atipamezole as an antagonist increases the value of this technique in macaques.     

Prognostic value of magnetic resonance imaging in dogs with paraplegia caused by thoracolumbar intervertebral disk extrusion: 77 cases (2000-2003)

OBJECTIVE: To determine whether magnetic resonance imaging findings in dogs with paraplegia caused by thoracolumbar intervertebral disk extrusion were predictive of clinical outcome. DESIGN: Retrospective case series. ANIMALS: 77 dogs. PROCEDURE: Medical records and magnetic resonance images were reviewed; clinical outcome was classified as successful (regained ability to walk with no more than mild neurologic deficits) or unsuccessful (severe neurologic deficits persisted). The prognostic value of magnetic resonance imaging was compared with prognostic value of deep pain perception, duration of clinical signs, and rate of onset of clinical signs. RESULT: 33 (43%) dogs had areas of hyperintensity of the spinal cord greater than or equal to the length of the L2 vertebral body on T2-weighted magnetic resonance images. All 44 dogs without areas of hyperintensity on T2-weighted images had a successful outcome, but only 18 of the 33 (55%) dogs with an area of hyperintensity did. Only 5 of 16 dogs with an area of hyperintensity that had also lost deep pain perception had a successful outcome. The odds ratio for an unsuccessful outcome for a dog with an area of hyperintensity (29.87) was higher than the odds ratio for a dog that had lost deep pain perception (5.24). Duration and rate of onset of clinical signs were not associated with clinical outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggest that results of magnetic resonance imaging can be used to predict clinical outcome in dogs with paraplegia caused by intervertebral disk extrusion.     

Magnetic resonance imaging of a canine eye with melanoma

An 8-year-old Beagle dog had exophthalmos of the left eye for the last two past months. On ophthalmoscopy, the intraocular lesion could not be evaluated due to the opacity of the cornea. Ultrasonography revealed that the eyeball was distorted in shape and shifted in position, however, the precise lesion could not be identified. On magnetic resonance (MR) imaging, the lesion was observed as hyperintense on T1-weighted and hypointense on T2-weighted images, similar to those reported in human melanoma. The lesion was histologically diagnosed to be malignant intraocular melanoma. Though this is only a case report, canine ocular melanoma may show the similar characteristic MR images as in human uveal malignant melanoma.     

Effects of midazolam-butorphanol, acepromazine-butorphanol and medetomidine on an induction dose of propofol and their compatibility in dogs

The effects of acepromazine-butorphanol (AB), midazolam-butorphanol (MB) and medetomidine (Med) on the induction dose of propofol and their compatibility with propofol were evaluated in client-owned dogs. All premedications induced good to excellent sedation and the induction dose of propofol was considerably reduced. Of the tested premedicants, Med induced the deepest sedation and the most potent dose-sparing effect. Induction of anesthesia was excellent to good in all dogs except for one dog premedicated with MB. Most dogs premedicated with AB or MB showed temporary apnea. Although other adverse effects such as bradycardia or hypotension may also occur, premedication with MB, AB or Med is a valuable technique for the induction of anesthesia with propofol in dogs in a clinical setting.     

Characterization of thermotolerant, fermentative yeasts from hot spring drainage

SUMMARY: Eight thermotolerant, ethanol-producing yeast strains were isolated from hot spring drainage at Rendaiji in Shizuoka Prefecture. The tolerance to elevated temperatures of three strains (RND13, 14 and 17) was studied in comparison with that of mesophilic yeasts. All three grew on a liquid culture at temperatures up to 42–45°C, with maximum growth rates at 37°C or 35°C, whereas the upper limit temperatures for fermentation were higher, ranging from 48 to 55°C. Above all, RND13 had higher ethanol productivity of 72.1% at 40°C for 24 h than that of 57.0% obtained by brewers' yeast at 25°C for 120 h. Regarding the taxonomy of RND13, 14, and 17, they were found to be Torulaspora delbrueckii , Dekkera sp., and Candida albicans , respectively. This is the first report on yeasts capable of fermentation over 51°C, as well as on the isolation of yeasts from a hydrosphere with elevated temperatures.     

Role of beta1 integrins in adhesion of canine mastocytoma cells to extracellular matrix proteins

The interactions of tumor cells with the extracellular matrix (ECM) are a crucial step in invasion and metastasis. Integrins are adhesive molecules forming heterodimers with alpha and beta subunits that play a definitive role in these interactions. In this study, mastocytoma (mast cell tumor: MCT) cell-ECM interaction was investigated using 3 canine MCT cell lines: CM-MC (originating from cutaneous MCT), VI-MC (originating from intestinal MCT), and CoMS (originating from oral MCT). Flow cytometric analysis showed that all cells highly expressed the integrin beta1 and alpha1 through alpha5 subunits and that they moderately expressed the alpha6 subunit. In adhesion studies, CoMS weakly but spontaneously adhered to fibronectin (FN), which was enhanced by phorbol ester (TPA), while CM-MC and VI-MC required cell activation by TPA to adhere to FN. Anti-beta1 and alpha5 integrin antibodies strongly inhibited cell adhesion to FN in CM-MC and CoMS and moderately inhibited cell adhesion in VI-MC. Only VI-MC adhered to laminin (LN) under activation by TPA. Anti-beta1 integrin antibodies strongly inhibited cell adhesion to LN, but all anti-alpha integrin antibodies failed to inhibit cell adhesion to LN. No cells adhered to collagen types I and IV. Canine MCT cells from different origins expressed similar integrin patterns; however, there were some differences in adhesive behavior in response to various ECM proteins and activating stimuli.