Harmful algal blooms are increasing worldwide, including those of Pseudo-nitzschia spp. producing domoic acid off the California coast. This neurotoxin was first shown to cause mortality of marine mammals in 1998. A decade of monitoring California sea lion (Zalophus californianus) health since then has indicated that changes in the symptomatology and epidemiology of domoic acid toxicosis in this species are associated with the increase in toxigenic blooms. Two separate clinical syndromes now exist: acute domoic acid toxicosis as has been previously documented, and a second novel neurological syndrome characterized by epilepsy described here associated with chronic consequences of previous sub-lethal exposure to the toxin. This study indicates that domoic acid causes chronic damage to California sea lions and that these health effects are increasing.

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Eighty-one Californian sea lions (Zalophus californianus) with signs of domoic acid toxicity stranded along the coast of California in 1998 when there were blooms of the domoic acid-producing alga Pseudonitzschia australis off-shore. In 2000, a further 184 sea lions stranded with similar clinical signs, but the strandings occurred both during detectable algal blooms and after the blooms had subsided. The clinical signs in these 265 Californian sea lions included seizures, ataxia, head weaving, decreased responsiveness to stimuli and scratching behaviour. Affected animals had high haematocrits, and eosinophil counts, and high activities of serum creatine kinase. They were treated supportively by using fluid therapy, diazepam, lorazepam and phenobarbitone. Fifty-five of the 81 sea lions (68 per cent) affected in 1998 and 81 of the 184 (44 per cent) affected in 2000 died despite the treatment. Three of the 23 sea lions which survived in 1998 were tracked with satellite and radiotransmitters; they travelled as far south as San Miguel Island, California, and survived for at least three months. Eleven of the 129 animals which were released stranded within four months of being released.

P38␣ is a protein kinase that regulates the expression of inflammatory cytokines, suggesting a role in the pathogenesis of diseases such as rheumatoid arthritis (RA) or systemic lupus erythematosus. Here, we describe the preclinical pharmacology of pamapimod, a novel p38 mitogen-activated protein kinase inhibitor. Pamapimod inhibited p38␣ and p38␤ enzymatic activity, with IC 50 values of 0.014 Ϯ 0.002 and 0.48 Ϯ 0.04 M, respectively. There was no activity against p38␦ or p38␥ isoforms. When profiled across 350 kinases, pamapimod bound only to four kinases in addition to p38. Cellular potency was assessed using phosphorylation of heat shock protein-27 and c-Jun as selective readouts for p38 and c-Jun NH 2 -terminal kinase (JNK), respectively. Pamapimod inhibited p38 (IC 50 , 0.06 M), but inhibition of JNK was not detected. Pamapimod also inhibited lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) ␣ production by monocytes, interleukin (IL)-1␤ production in human whole blood, and spontaneous TNF␣ production by synovial explants from RA patients. LPS-and TNF␣-stimulated production of TNF␣ and IL-6 in rodents also was inhibited by pamapimod. In murine collagen-induced arthritis, pamapimod reduced clinical signs of inflammation and bone loss at 50 mg/kg or greater. In a rat model of hyperalgesia, pamapimod increased tolerance to pressure in a dose-dependent manner, suggesting an important role of p38 in pain associated with inflammation. Finally, an analog of pamapimod that has equivalent potency and selectivity inhibited renal disease in lupus-prone MRL/lpr mice. Our study demonstrates that pamapimod is a potent, selective inhibitor of p38␣ with the ability to inhibit the signs and symptoms of RA and other autoimmune diseases.

Animal models of human disease are commonly utilized to gain insight into the potential efficacy and mode of action of novel pharmaceuticals. However, conventional (healthy) rodent and nonrodent models are generally utilized in nonclinical safety testing. Animal models of human disease may be helpful in understanding safety risks of compounds in nonclinical or clinical development, with their greatest value being in targeted or hypothesis-driven studies to help understand the mechanism of a particular toxicity. Limitations of animal models of disease in nonclinical safety testing include a lack of historical control, heterogeneity in disease expression, a limited life span, and confounding effects of the disease. In most instances, animal models of human disease should not be utilized to supplant testing in conventional animal models. While of potential benefit, testing in an animal model of human disease should only be taken after adequate consideration of relevance along with benefits and limitations of the proposed model.

ABSTRACT:Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudonitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic findings included systemic and localized inflammation and bacterial infections of amniotic origin, placental abruption, and brain edema. The primary lesion in five animals with measurable domoic acid concentrations was brain edema, a common finding and, in some cases, the only lesion observed in aborted premature pups born to domoic acid-intoxicated females in rehabilitation. Blubber organochlorine concentrations were lower than those measured previously in premature sea lion pups collected in the 1970s. While the etiology of abortion and premature parturition was varied in this study, these results suggest that domoic acid contributes to reproductive failure on California sea lion rookeries.

Abstract. Domoic acid, produced by marine algae, can cause acute and chronic neurologic sequela in California sea lions (Zalophus californianus) from acute toxicity or sublethal exposure. Eight sea lions, representing acute and chronic cases, both sexes, and all age classes, were selected to demonstrate a concurrent degenerative cardiomyopathy. Critical aspects of characterizing the cardiomyopathy by lesion distribution and morphology were the development of a heart dissection and tissue-trimming protocol and the delineation of the cardiac conducting system by histomorphology and immunohistochemistry for neuron-specific protein gene product 9.5. Histopathologic features and progression of the cardiomyopathy are described, varying from acute to chronic active and mild to severe. The cardiomyopathy is distinguished from other heart lesions in pinnipeds. Based on histopathologic features, immunopositive staining for cleaved caspase-3, and comparison with known, similar-appearing cardiomyopathies, the proposed pathogenesis for the degenerative cardiomyopathy is the primary or at least initial direct interaction of domoic acid with receptors that are suspected to exist in the heart. LCarnitine, measured in the heart and skeletal muscle, and troponin-I, measured in serum collected at the time of death from additional animals (n 5 58), were not predictive of the domoic acid-associated cardiomyopathy. This degenerative cardiomyopathy in California sea lions represents another syndrome beyond central neurologic disease associated with exposure to domoic acid and may contribute to morbidity and mortality.

A 6-year-old male castrated Greyhound was presented to the William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, with a 4-week history of apparent spinal pain and paraparesis. There was no improvement despite treatment consisting of oral carprofen (unknown dose) for 10 days followed by a tapering course of oral prednisone for 6 days before referral (1.2-0.2 mg/kg/d). Abnormalities on physical examination included 5% dehydration, a large flaccid bladder that was easily expressed, moderate conjunctivitis , and mild generalized patchy alopecia. On neurolog-ical examination, the dog was ambulatory with marked paraparesis and absent conscious proprioception in both pelvic limbs. The patellar, gastrocnemius, and pelvic limb withdrawal reflexes were decreased bilaterally, the cuta-neous trunci reflex was absent caudal to L4, and the perineal reflex and anal tone were absent. The tail was flaccid with intact superficial pain sensation. The dog was painful with dorsal palpation of the lumbar spine. The neurological abnormalities were consistent with an L4-Cd myelopathy. A CBC and serum biochemistry had mild abnormalities , interpreted as clinically insignificant. Urinalysis indicated a specific gravity of 1.048 and marked protein-uria (41 on sulfosalicylic acid method). Thoracic radiographs and abdominal ultrasound examination indicated no clinically relevant findings. After vertebral column radiographs, where no abnormalities were seen, two 22 G 3.5-in. spinal needles were placed, 1 at the L4-5 and 1 at the L5-6 intervertebral disc spaces, but cerebrospinal fluid (CSF) could not be obtained. CSF was collected from the cerebellomedullary cistern. A diagnostic myelogram was not performed and, therefore, magnetic resonance (MR) images of the lum-bar spinal cord followed by those of the brain were acquired with a 1.5-T scanner. a T1-weighted (T1W) images and T2-weighted (T2W) images included the L3 vertebra to the caudal vertebrae and the entire brain to the C3 vertebra. The spinal cord was enlarged and slightly elevated and dorsoventrally flattened from the L4 through the S2 vertebrae. On the T2W images, there was intramedullary hyperintensity of the lumbar and sa-cral segments of the spinal cord and the cauda equina, with partial loss of epidural fat signal and gray and white matter definition in the mid lumber region (Fig 1A). After IV contrast administration, b there was moderate parenchymal contrast enhancement and mild diffuse Fig 1. (A) T2-weighted sagittal magnetic resonance images (MRI) from dog 1. Note the intramedullary hyperintensity compared with spinal cord gray matter, loss of epidural fat signal, and gray/white matter definition. (B) T1-weighted sagittal MRI and (C) T1-weighted sagittal MRI postcontrast from dog 1. There is moderate parenchymal contrast enhancement and mild diffuse meningeal enhancement (arrow) from L4 to the conus medullaris.