Acute fatal toxoplasmosis in squirrels (Sciurus carolensis) with bradyzoites in visceral tissues.

Acute toxoplasmosis was diagnosed in 3 gray squirrels (Sciurus carolensis) from Louisiana and Pennsylvania. The predominant lesion was multifocal necrosis in several organs, especially of the lymph nodes. Numerous Toxoplasma gondii tachyzoites were seen in lesions, and the diagnosis was confirmed immunohistochemically by reaction with polyclonal T. gondii-specific antibodies. Tissue cysts were seen in several organs, including lung alveoli. The presence of tissue cysts in alveoli of pet squirrels maybe of public health concern if tissue cysts excreted in nasal secretions are swallowed by children.

Mohs micrographic surgery: a technique for total margin assessment in veterinary cutaneous oncologic surgery.

Mohs micrographic surgery (MMS) is the gold standard for the excision of locally invasive cutaneous malignancies in human dermatological surgery. Using a unique horizontal sectioning technique, MMS enables 100% surgical margin assessment and provides the lowest recurrence rates for locally invasive tumours. The purposes of this preliminary study were to explore the feasibility of application of MMS in the veterinary setting and to establish practical advantages and limitations of its use in a pilot programme. It was hypothesized that MMS technique could provide 100% tumour margin assessment using frozen and/or formalin-fixed horizontal histopathologic sections. Tumour excision and colour-coded mapping were performed, and specimen tissue was fixed using either frozen sections or formalin-fixed sections. Horizontal sections were assessed for quality and presence and location of neoplastic cells based on the mapped orientation. The MMS technique was used in the excision of six squamous cell carcinomas and five mast cell tumours. In all cases, the MMS permitted 100% tumour margins examination.

A modified biopsy technique to improve histopathological evaluation of avian skin.

Skin biopsies are a viable diagnostic tool in avian dermatology, however, the thinness of avian skin makes it difficult to prevent rolling and contraction of skin biopsy specimens during collection and fixation. The difficulty orienting such rolled samples during processing ultimately interferes with the establishment of a histopathological diagnosis. We describe a modified skin biopsy procedure for obtaining avian skin biopsy specimens. In this technique nontranslucent self-adhesive tape (Scotch tape) was attached to skin biopsy sites before obtaining skin biopsies using a standard skin biopsy punch instrument. A total of 23 skin biopsy specimens were obtained: 15 from nonfeathered skin of 12 normal Hispaniolan parrots, 3 from feathered skin of 2 normal birds and 5 from feathered skin of 3 psittacines presented for pathologic feather-picking. All 23 skin specimens consistently adhered to the tape during the biopsy procedure. The specimens were fixed in 10% neutral phosphate-buffered formalin. During processing, no curling or rolling of specimens occurred, and all specimens could be easily orientated for correct trimming and subsequent histopathological evaluation. The tape technique did not produce any appreciable artefacts. Remnants of the tape were microscopically evident above the stratum corneum assuring that none of the stratum corneum was lost during processing. Obtaining avian skin biopsy specimens using this modified tape technique is easy and ensures flat fixation of the skin biopsy specimens, which later allows trimming at right angles, and through the longitudinal diameter of feather follicles for accurate histopathologic evaluation.

Induction of feline flea allergy dermatitis and the incidence and histopathological characteristics of concurrent indolent lip ulcers.

The objectives of this study were to characterize the role of intermittent vs. continual flea exposure in the development of flea allergy dermatitis (FAD) in cats, assess the accuracy of intradermal skin testing (IDST) and in vitro testing, and document the incidence and histopathological features of indolent lip ulcers. Ten flea-naive cats were divided into two groups. One group received intermittent flea exposure for 120 days. Thereafter, both groups of cats received continuous flea exposure for 120 days. In vitro testing for flea salivary antibody and IDST utilizing both whole flea antigen and flea salivary antigen were performed. Eight of 10 cats developed clinical signs of FAD within 3 months and five of these eight cats developed lip ulcers which where characterized histopathologically by ulceration with predominantly neutrophilic inflammation and surface bacterial colonization. There was no association between the presence or absence of clinical signs and positive IDST or in vitro results, and no difference in the development of clinical signs was noted between the two groups of cats.

Effect of hyperbaric oxygen on lipid peroxidation in free skin grafts in rats.

OBJECTIVE: To document that free skin grafts treated with hyperbaric oxygen (HBO) are at greater risk for reperfusion injury, resulting in lipid peroxidation, than are free skin grafts without HBO treatment. ANIMALS: 40 Sprague-Dawley rats. PROCEDURE: Free skin grafting was performed bilaterally on each rat. The HBO-treated rats received HBO twice daily for 90 minutes at 2 ATA. Biopsy specimens were taken from each rat at the time of grafting and on days 2, 4, 7, 10, 14, 21, and 28, then were processed for tissue concentration of total glutathione (GSHt), glutathione peroxidase activity (GPx), and presence of thiobarbituric acid-reactive substances (TBARS). RESULTS: Both groups had a similar pattern of change in TBARS and GPx values--initial increase, returning to preoperative values at days 21 (control) and 28 (HBO). The GPx activity peaked later than did TBARS concentration (day 7 vs day 4). The pattern was significantly more pronounced in HBO-treated than in control rats. Both groups had a similar pattern of change in GSHt values-significant decrease from preoperative concentration at day 2, return to preoperative concentration by days 4 (HBO) and 7 (control), increase above preoperative concentration by day 21, and return to preoperative concentration by day 28. Obvious visual or histologic differences in the grafts were not detected between groups. CONCLUSIONS: Cellular effects of oxidative stress were apparent in both groups of rats; however, the degree of these effects was exacerbated by HBO. In the face of enhanced cellular lipid peroxidation, use of HBO for the treatment of free skin grafts must be questioned.

Juvenile rhabdomyosarcomas in two dogs.

Juvenile rhabdomyosarcomas were diagnosed in two young dogs based on the results of histopathology, phosphotungstic acid-hematoxylin stain, immunohistochemistry, and the age of the dogs. One dog, an 11-month-old Rottweiler, had tumor masses in the maxillary gingiva and the urinary bladder. Histologically, the gingival mass was an alveolar type of rhabdomyosarcoma and the urinary bladder mass was an embryonal type. The other dog, a 1.5-year-old Basset Hound, had an embryonal rhabdomyosarcoma involving the oropharynx and the temporal muscles, with metastasis to the regional lymph node and lungs.

Superficial spreading pyoderma and ulcerative dermatitis in a ferret.

Abstract A case report of an 8-month-old ferret with severe ulcerative dermatitis of the ventral abdomen and medial thigh regions is presented. Cutaneous biopsies of the periphery of the ulcerative lesions revealed large, confluent, superficial epidermal pustules containing inflammatory cellular debris and Gram-positive cocci, as well as perifollicular dermal necrosis. These histological findings are consistent with superficial spreading pyoderma in conjunction with dermal coagulative necrosis. Résumé- Un furet mâle de 8 mois est présenté pour une dermite ulcérative sévère du ventre et des faces internes des cuisses. Des biopsies cutanées réalisées à la périphérie des lésions ulcératives montrent la présence d'importantes pustules épidermiques contenant des débris cellulaires inflammatoires et des bactéries cocci Gram positif, ainsi qu'une nécrose dermique périfolliculaire. Ces éléments histopathologiques sont en faveur d'une pyodermite superficielle extensive associée à une nécrose de coagulation du derme. [King, W. W., Lemarié, S. L., Veazey, R. S., Hodin, E. C. Superficial spreading pyoderma and ulcerative dermatitis in a ferret (Pyodermite extensive superficielle et dermite ulcérative chez un furet). Veterinary Dermatology 1996; 7: 43-47.] Resumen Presentamos el caso clínico de un hurón de 8 meses con una dermatitis ulcerativa grave en abdomen ventral y muslo medial. El estudio de biopsias de la periferia de las zonas ulceradas reveló la presencia de grandes pústulas superficiales epidérmicas confluentes que contenían restos celulares inflamatorios y cocos Gram-positivo, así como necrosis perifolicular en la dermis. Estos hallazgos histológicos son compatibles con una pioderma de extensióin superficial en conjunción con necrosis dérmica coagulativa. [King, W. W., Lemarié, S. L., Veazey, R. S., Hodin, E. C. Superficial spreading pyoderma and ulcerative dermatitis in a ferret (Pioderma de extension superficial y dermatitis ulcerativa en un huron). Veterinary Dermatology 1996; 7: 43-47.] Zusammenfassung- Es wird ein Fallbericht vorgestellt, bei dem ein 8 Monate altes Frettchen an schwerer ulzerativer Dermatitis des ventralen Abdomens und der medialen Schenkelregionen leidet. Hautbiopsien aus der Peripherie der ulzerativen Veränderungen zeigten große, konfluierende, oberflächliche epidermale Pusteln, die entzündlichen Zelldebris und Gram-positive Kokken enthielten, sowie eine perifollikuläre dermale Nekrose. Diese histologischen Befunde stimmen mit der oberflächlich ausgebreiteten Pyodermie in Verbindung mit einer dermalen Koagulationsnekrose überein. [King, W. W., Lemarié, S. L., Veazey, R. S., Hodin, E. C. Superficial spreading pyoderma and ulcerative dermatitis in a ferret (Oberflächlich ausgebreitete Pyodermie und ulzerative Dermatitis bei einem Frettchen). Veterinary Dermatology 1996; 7: 43-47.].

Effect of deferoxamine and hyperbaric oxygen on free, autogenous, full-thickness skin grafts in dogs.

Free, autogenous, full-thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight, IV), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, IV). All dogs (DEF-HES/HBO- and HES/HBO-treated) were exposed to 60 minutes of hyperbaric oxygen (HBO) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in HES/HBO-treated dogs (mean +/- SD, 13.3 +/- 21.3%; median, 3.0%) than in DEF-HES/HBO-treated dogs (64.7 +/- 39.2%; 88.3%; P = 0.095, Mann-Whitney two-tailed test). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs (r = 0.91) and for HES/HBO-treated dogs (r = 0.97). The DEF-HES/HBO-treated dogs had less consistent correlation (r = 0.67). Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of DEF-HES/HBO-treated dogs. These cells were also observed in the dermis, but not subcutaneous tissue of the control skin sections, and in some viscera of DEF-HES/HBO-treated dogs. Deferoxamine appears to attenuate the detrimental effect of HBO and HES on survival of free skin grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Malignant retroperitoneal paraganglioma in a horse.

A large primary retroperitoneal sublumbar neoplasm in a horse, with disseminated neoplastic foci in the brain, lung, kidney and spleen is described. The diagnosis was based on light microscopical studies and positive immunostaining for neuron-specific enolase. Because of the location of the primary tumour mass, the aortico-sympathetic ganglion (organ of Zukerkandl) is proposed as the origin.

Effect of deferoxamine-hydroxyethyl pentafraction starch on free, autogenous full-thickness skin grafts in dogs.

Free, autogenous, full-thickness skin grafting was performed on 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight, IV), and 5 dogs were given 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, IV). The percentage of viable graft on day 10 was higher, but not significantly so, in DEF-HES-treated dogs (mean +/- SD, 72.6 +/- 24.8%; median 76.5%) than in HES-treated dogs (mean +/- SD, 46.7 +/- 34.3%; median, 48.8%). A trend for a positive correlation between the percentage of viable graft (on day 10) and the percentage of original graft area (on day 28) was observed in HES- and DEF-HES-treated dogs; this trend was significant in HES-treated dogs (P = 0.012). Both groups had significant positive correlation between percentage of viable graft on day 10 and percentage of haired skin on day 28 (HES, P = 0.000002; DEF-HES, P = 0.0148). A unique finding in DEF-HES treated dogs was the consistent observation of foamy macrophages in the dermis adjacent to the grafts, in deep subcutaneous tissue below the grafts, and in normal dermis.

Anaerobic bacterial infections causing osteomyelitis/arthritis in a dog.

A 3-year-old German Shepherd Dog was examined for lameness, signs of pain, swelling, a draining fistulous tract, and osteolysis after a dog bite on the left carpus. After failure of the lesion to respond to several antibiotics, Peptostreptococcus sp and Propionibacterium sp were isolated from swab specimens and then from surgically collected bone and soft tissue specimens. The bone fragments had mild purulent osteomyelitis associated with numerous gram-positive rods and cocci. The dog was successfully treated by surgical debridement of the lesion and clindamycin administration.

Papillomavirus infection of aged Persian cats.

Papillomavirus infection was confirmed in 2 Persian cats with sessile hyperkeratotic skin lesions. Skin lesions were not typical papillomas as found in other species. Papillomavirus were demonstrated in negative stain preparations of homogenized tissue and within nuclei of cells in the stratum granulosum. Papillomavirus group-specific antigens were detected within nuclei corresponding to those containing virions. Attempts to transmit this disease to other cats or propagate the virus in tissue cultures were unsuccessful. A 7.8-kilobase DNA molecule was present in low-stringency Southern blots using a bovine papillomavirus type 1 cloned DNA probe. In reverse Southern blots, the cat papillomavirus hybridized under conditions of low stringency with all papillomavirus genomes tested. Combined with limited restriction endonuclease restriction mapping, the above information indicates that the feline cutaneous papillomavirus is a unique virus type and thus expands the list of hosts known to be infected by papillomaviruses.

Leptospira abortion in horses.

Leptospira infection was diagnosed as the cause of 4 late-term equine abortions/stillbirths and 1 neonatal death in Louisiana. The most consistent gross and microscopic lesions were icterus and interstitial nephritis, respectively. Diagnoses were based on visualization of compatible spirochetes in Warthin-Starry-stained sections of kidney, liver, and placenta. Confirmation by immunofluorescence was made in 2 cases.

Micronema deletrix-induced granulomatous osteoarthritis in a lame horse.

Necropsy of a chronically lame 16-year-old thoroughbred gelding revealed granulomatous osteomyelitis and polyarthritis due to a widely disseminated infection by Micronema deletrix. Diagnosis was based upon the nematode's morphology with its characteristic rhabditiform oesophagus. Granulomata, often containing one or more centrally located M. deletrix, were observed histologically in sections prepared from femur, kidney, stomach, lung, adrenal gland and sublumbar lymph nodes. Neither verminous meningo-encephalitis nor cephalic granulomata, which are the more commonly described lesions, was found.

Cryptococcosis in a pup.

Disseminated cryptococcosis was diagnosed as the cause of death of a 2-week-old pup. Cryptococcus neoformans was isolated from the dam's vaginal discharge, but not from the dam's milk, blood, feces, or environment. During succeeding months, C neoformans was isolated repeatedly from the dam's vagina, even though vaginitis was not evident. One year after the death of the 2-week-old pup, cryptococci could not be isolated from the dam's vagina, and evidence of cryptococcosis was not detected in pups of the dam's next litter. This case was unusual because cryptococcosis has been reported previously only in dogs 11 months or older and because the source of the pup's infection may have been the dam rather than the environment.

Stabilization of atlantoaxial subluxation secondary to atlantooccipital malformation in a Devon calf.

Atlantoaxial subluxation secondary to atlantooccipital malformation in a 14-day-old female Devon calf was corrected by alignment and stabilization of the atlantoaxial joint. Stabilization was achieved by the ventral placement of pins and screws, and the dorsal placement of a figure 8 tension band wire. At 2 and 14 days post operatively, adequate alignment of the atlantoaxial joint was confirmed radiographically. Following surgery the calf improved clinically, but was terminated 14 days following the surgery due to a pneumonia. At necropsy the fixation was stable and spinal cord decompression had been achieved. It was concluded that this technique could be utilized to allow decompression, anatomical alignment, and stabilization of an atlantoaxial subluxation secondary to atlantooccipital malformation in a calf. At necropsy, there was gross and histologic evidence of congenital fusion of the basioccipital bone to the malformed atlas.

Inhibition of passive systemic anaphylaxis in guinea pigs by Trichinella spiralis infection.

Thirty of 33 guinea pigs experimentally infected with Trichinella spiralis survived passive systemic anaphylactic reactions which were fatal for 32 of 33 uninfected controls. Guinea pigs were infected with viable excysted trichinella larvae 20 to 32 days before they and uninfected controls were sensitized by intracardiac injection of rabbit anti-bovine serum albumin. Animals were challenged 24 hours later by intracardiac injection of bovine serum albumin. Respiratory anaphylaxis was observed in all challenged animals. Protection from passive anaphylaxis in parasitized guinea pigs was most likely due to preemption of mast cell receptors by parasite-induced antibody with consequent blockage of passive sensitization.