Filtration of Green Algae and Cyanobacteria by Freshwater Mussels in the Partitioned Aquaculture System

Abstract.— The freshwater mussel Elliptio complanata was provided water containing green algae and cyanobacteria delivered from the Partitioned Aquaculture System (PAS) at eight flow rates to determine algal filtration rates as mg of particulate organic carbon (POC)/kg wet tissue weight per h. The dominant taxon in cyanobacterial waters was Microcystis while the dominant taxa in green algal waters were Scenedesmus and Ankistrodesmus . The cell counts of Scenedesmus and Ankistrodesmus were the only algal taxa that were significantly different between the incoming water and water filtered by mussels. Filtration rates of POC obtained from green algal water were significantly greater than from cyanobacteria-dominated waters at all flow rates. A significant increase in mean filtration rate was observed as flow rates increased. The filtration rate of green algae increased as POC concentration increased, peaking at 28 mg C/L. A maximum filtration rate was not observed with cyanobacterial waters.     

Actinomycin D for Reinduction of Remission in Dogs With Resistant Lymphoma

Twenty-five dogs with malignant lymphoma refractory to chemotherapy were treated with actinomycin D at a median dose of 0.7 mg/m² (range, 0.5 to 0.9 mg/m²) every 3 weeks. The dogs treated had received between 2 and 8 chemotherapeutic agents (median 7), for a median of 266 days before being treated with actinomycin D. For 23 of the 25 dogs, previous chemotherapy included doxorubicin. No dog responded to actinomycin D chemotherapy.     

Hyperlipemia and Ketonuria in an Alpaca and a Llama

An alpaca and a llama in late stages of gestation were evaluated for lethargy, anorexia, and recumbency. Both camelids had cloudy, white, turbid serum, elevated serum triglyceride (1564, 5658 mg/dL, respectively) and cholesterol (158, 297 mg/dL, respectively) concentrations, and ketonuria. Signs of fetal stress were evident ultrasonographically in the alpaca, and a live cria was delivered by Cesarean section performed under general anesthesia. The alpaca developed severe metabolic acidosis, hepatic lipidosis, and acute renal failure secondary to renal lipidosis and died 36 hours after admission despite medical therapy. Histopathology revealed renal and hepatic lipidosis and neutrophilic pancreatitis. The cria died 72 hours after birth. The llama responded to IV electrolyte, dextrose, and regular crystalline insulin therapy. The pregnancy was maintained, and the llama was discharged from the hospital 20 days after admission. Two months after discharge, the llama gave birth to a live, 5 kg cria. Findings of hypertriglyceridemia, hypercholesterolemia, elevated sorbitol dehydrogenase activity, metabolic acidosis, azotemia, and ketonuria occurred in these two camelids. Based on this report, camelids appear to be similar to both horses and cattle in their response to severe energy imbalances in late gestation.     

Plasma Cell Myeloma in the Horse

Plasma cell myelomas in horses have been reported infrequently. Data from 10 cases, 9 from the literature and 1 new case, are used to characterize the disease in the horse. Hot-blooded horses (7/10), specifically Quarter Horses (4/10), were most often affected. Median age at diagnosis was 11 years (range, 3 mo-22 yr) and both male (5) and female horses (5) were represented equally. Clinical findings included weight loss (6/8), anorexia (4/8), fever (4/8), limb edema (4/8), pneumonia (3/8), rear leg paresis/ataxia (3/8), epistaxis (3/8), palpable lymphadenopathy (2/8), and bone pain (2/8). Anemia (8/8) was present routinely, and in three horses, RBCs were macrocytic. Leukopenia (2/8), thrombocy-topenia (2/8), and circulating plasma cells (3/8) were variable findings. Except for abnormal protein concentrations and hyponatremia (3), abnormal results from serum biochemical analysis including hypo-cholesterolemia (1), hypercalcemia (1), and azotemia (1) were reported infrequently. Hyperproteinemia (8/9), hypoalbuminemia (7/9), and hyperglobulinemia (8/9) were characteristic but not invariable findings. Monoclonal proteins (7/7) were detected in the α₂, β, or γ region by serum electrophoresis. The paraprotein's heavy chain, determined in four horses, was a subclass of IgG. Three horses had decreased concentrations of normal immunoglobulins. Variable proteinuria (trace to 4+) was detected by routine urinalysis in four of six horses. Bence Jones proteinuria was detected in one of five horses (heat precipitation) and monoclonal proteins were detected in two of three electrophoresed urine samples. Three of the horses had lytic bone lesions detected radiographically. Bone marrow aspirates were diagnostic in two of five horses. Atypical plasma cells or increased numbers of plasma cells or both were present in histologic sections of bone marrow in six of eight horses. Common extraosseous sites of plasma cell infiltration included lymph nodes (8/8), kidney (5/8), spleen (5/8), liver (3/8), lung (3/8), brain (2/8), and orbit (2/8). Two horses had intracellular and extracellular crystalline deposits.     

BACTERIAL ENDOCARDITIS WITH THROMBUS FORMATION AND ABSCESSATION IN A HORSE

A 2.5 year old Appaloosa stallion with progressive weight loss and a heart murmur was diagnosed as having vegetative endocarditis of the right atrioventricular valves with a mass in the right atrium. The ultrasonographic appearance of the lesion was characterized by extreme reverberation. On postmortem examination, a 9 cm diameter thrombus was found within the right atrium and auricle, occupying approximately 80% of the chamber volume. Additionally, a lenticular abscess extended throughout the parietal cusp of the right atrioventricular valve. Histologic examination revealed that the lesions were septic with numerous gram positive cocci in short chains, suggestive of Streptococcus equi , and gram negative rods.     

MAGNETIC RESONANCE IMAGING FEATURES OF EQUINE NIGROPALLIDAL ENCEPHALOMALACIA

Magnetic resonance imaging (MR) was used to make a diagnosis of equine nigropallidal encephalomalacia in a horse. Equine nigropallidal encephalomalacia is a neurodegenerative disease that has many characteristics with Parkinson-like diseases in humans. Historically, horses were euthanized based on clinical signs and exposure to the toxic weed, yellow star thistle (Centaurea solstitialis). Previously, the disease has only been confirmed on necropsy. MR imaging can provide accurate and sensitive visualization of typical lesions seen in the brain of horses affected with equine nigropallidal encephalomalacia. Lesions were seen on T1-weighted, T2-weighted and proton density images. There was no contrast enhancement following Gd-DTPA administration. Lesions seen on MR were confirmed at necropsy. Using MR to confirm a diagnosis of equine nigropallidal encephalomalacia will prevent unnecessary suffering of horses and expense to owners that would otherwise incur, while further diagnostics are performed.     

MAGNETIC RESONANCE IMAGING FEATURES OF MULTILOBULAR OSTEOCHONDROSARCOMA IN 3 DOGS

Three dogs with multilobular osteochondrosarcoma of the skull were evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2, proton weighted and post contrast T1W images were obtained with a 1.5 Tesla magnet. The MR imaging findings were similar in all three dogs with mixed signal intensities in the T1W, T2W and proton weighted images and fairly large areas of contrast enhancement in the post contrast T1W images. The extent of brain and soft tissue involvement were well delineated and provided useful information concerning surgical planning. MR imaging provided a useful method of evaluating dogs with skull tumors.     

Coccidioidomycosis in 48 Cats: A Retrospective Study (1984–1993)

Coccidioidomycosis was diagnosed in 48 cats. Forty-one cases were identified within a period of 3 years. Coccidioides immitis was revealed by cytological or histopathological examinations, or culture in 70% of cats. The remaining 30% of cases were diagnosed by appropriate clinical signs, radiographic lesions, and serological test results. The average age of affected cats was 6.2 years with a median age of 5.0 years. Fifty-four percent (n = 26) were female and 46% (n = 22) were male. Domestic shorthaired and longhaired breeds comprised 89% (n = 41) of affected cats. Sixty-seven percent of cases were diagnosed during the 6-month period of December through May. Cats infected with C immitis were presented for evaluation of dermatologic (56%), respiratory (25%), musculoskeletal (19%), and neurological or ophthalmologic signs (19%). Fever, inappetence, and weight loss were present in 44% of the cats. Duration of clinical signs before diagnosis was less than 4 weeks in 85% (n = 42) of cats, with an average of 3.8 weeks and a median of 2 weeks. Agar gel immunodiffusion tests were positive in all 39 cats tested at sometime during the course of their disease. Hyperproteinemia (greater than 7.9 g/dL) was present in 52% (10/23) of cases. The majority of cats (n = 39) were negative for feline leukemia virus. Antibodies to feline immunodeficiency virus were absent in the 19 cats tested. Ketoconazole was the most common antifungal agent used to treat cats with Coccidioidomycosis. Duration of treatment ranged from less than 1 week to 43 months. Thirty-two cats are currently asymptomatic, with or without treatment. Eleven cats died or were euthanized. Five cats were lost to follow-up. Ketoconazole likely is more suppressive than curative because relapses were common after discontinuing therapy.