Histopathologic changes in the brain, heart, and skeletal muscle of rhesus macaques, ten days after exposure to soman (an organophosphorus nerve agent).

BACKGROUND AND PURPOSE: Soman, an organophosphorus, anticholinergic, chemical warfare nerve agent, is studied at few research facilities, and there have been few pathologic studies of soman-exposed primates. We describe the brain, heart, and skeletal muscle lesions, review lesions described in literature, and discuss possible pharmacologic mechanisms for soman-induced neuron necrosis. METHODS: In this retrospective, histopathologic study, records were obtained for 36 rhesus macaques (Macaca mulatta) that were euthanized 10 days after soman exposure, from a larger group of 103 monkeys that were exposed to soman and used for pharmacologic and lethality studies. RESULTS: Brain lesions were seen in 9 of 15 animals that convulsed and in only 1 of 21 that did not convulse. The brain lesions in our primates were limited to the hippocampus, amygdala, and thalamus (of one animal), and consisted of neuron necrosis and dropout, spongiosis, gliosis, astrocytosis, and vascularization. Heart lesions consisted of myocardial degeneration and necrosis. Three animals had brain and heart lesions, 7 had brain lesions only, and 3 had heart lesions only. Skeletal muscle lesions, although minimal to mild, were in most of the animals, whether they had convulsed, but most had muscular tremors. These lesions were in the biceps brachii (11 of 22 monkeys), anterior tibialis (8/22), biceps femoris (7/22), flexor carpi radialis (5/22), gastrocnemius (3/22), and diaphragm (1/22). The limited literature on soman lesions in primate brain and heart, and the limited information on skeletal muscle lesions, is reviewed. CONCLUSIONS: Brain lesions were not as wide-spread as reported in other studies of primates and rodents, and were significantly associated with convulsions. Unlike other studies using rodents, we observed poor correlation between heart and brain lesions; thus, a single hypothesis to explain the pathogenesis for the brain and heart lesions may be difficult to establish.

Malignant lymphoma of the meninges in two dogs.

Two cases of malignant lymphoma of the leptomeninges in dogs are described. Both involved the subarachnoid space overlying the cerebrum and cerebellum and in one dog there was infiltration of neoplastic lymphocytes into the leptomeninges of the cervical spinal cord and nerve roots. These cases appeared to represent primary meningeal lymphoma, except that lymphoma was present in an ovary of one of the dogs and here the meningeal lymphocytes were demonstrated to be B cells by the peroxidase-antiperoxidase method for cytoplasmic immunoglobulin. Meningeal lymphoma, primary or metastic, is rare in dogs. The differential diagnosis is discussed and includes reticulosis, sarcomatosis of the meninges, and the diffuse spread of an oligodendroglioma in the subarachnoid space. A tentative diagnosis of meningeal lymphoma in these cases could be made by examination of the cerebrospinal fluid cells.

Hepatic and gastric amebiasis in black and white colobus monkeys.

Three cases of hepatic amebiasis and one case of gastric amebiasis were diagnosed in black and white colobus monkeys during a 9-month period. The diagnosis was difficult because of the absence of trophozoites and cysts in the feces and because of few trophozoites found in many of the hepatic lesions. Indirect hemagglutination titers were diagnostic in 2 monkeys.

Effect of molybdate on androgen receptor levels in canine prostate.

A comparative study on the stabilizing effect of sodium molybdate on androgen receptors was performed using canine prostates. Prostates from intact male dogs of mixed breeds were run in parallel sucrose density gradient analyses, using buffer systems with or without molybdate. Prostates that were homogenized in a molybdate buffer showed a significant increase in androgen receptor content relative to those in a molybdate-free system.

Psittacine tuberculosis.

Two cases of tuberculosis in psittacine birds were reported and the literature reviewed. One case was in a parakeet and this species was reported to be resistant to mycobacterial infection. No other case of parakeet tuberculosis was found in the literature. The other case was in a parrot. Historically, tuberculosis in parrots was common in European aviary collections, but case reports in the United States were few. The disease in parrots is of zoonotic interest, as they are unique among birds in being susceptible to mammalian strains of mycobacteria. The tuberculomatous aspect of the intestinal lesion in the parrot case described was unusual.

Acute viral hepatitis in California sea lions.

Acute viral hepatitis was diagnosed in five California sea lions (Zalophus californianus) stranded along the Los Angeles coast. Light microscopy revealed large nuclear inclusion bodies in hepatocytes. Electron microscopy provided evidence that these inclusion bodies were composed of adenovirus-like virions. Attempts to grow the virus in cell culture systems were unsuccessful.