RESUMEN
In mammals the cytochrome P450 3A (CYP3A) subfamily isoforms are primarily expressed in liver and intestines with lesser amounts found in other tissues. The aim of this study was to examine the cellular localization and the expression pattern of CYP3A27 in the gastrointestinal tract (GI tract) of a freshwater teleost species, the rainbow trout (Oncorhynchus mykiss), a fish model used extensively for toxicological and carcinogenesis research. Using an avidin biotinylated enzyme complex and 3,3'-diaminobenzidine staining, strong cytoplasmic immunohistochemical staining was observed for CYP3A27 protein in hepatocytes and in enterocytes of the intestinal ceca and the proximal descending intestine when probed with a polyclonal antibody raised against rainbow trout P450 LMC5, a CYP3A protein. The intensity of epithelial staining decreased distally along the GI tract with faint staining observed in the epithelial cells examined near the vent. Western blot analysis was supportive of the immunohistochemistry results. Northern blot analysis also demonstrated that CYP3A27 mRNA was expressed along the entire GI tract. The major area of CYP3A27 mRNA expression was in the intestinal ceca, followed by the proximal descending intestine, at levels that were about three- to five-fold and two- to four-fold, respectively, greater than seen in the liver of the fish studied. Monooxygenase activities of intestinal ceca microsomes against testosterone and progesterone confirmed the presence of active CYP3A enzyme in this tissue. These results suggest that the intestine of rainbow trout may possesses substantial capacity for first-pass metabolism of xenobiotics by CYP3A27, which makes it an excellent model in which to study the consequence of such metabolism.
Asunto(s)
Hidrocarburo de Aril Hidroxilasas , Sistema Enzimático del Citocromo P-450/metabolismo , Sistema Digestivo/enzimología , Oncorhynchus mykiss/metabolismo , Oxidorreductasas N-Desmetilantes/metabolismo , Animales , Northern Blotting , Western Blotting , Ciego/enzimología , Citocromo P-450 CYP3A , Sistema Enzimático del Citocromo P-450/biosíntesis , Sistema Enzimático del Citocromo P-450/genética , Sistema Digestivo/metabolismo , Femenino , Regulación Enzimológica de la Expresión Génica , Hidroxilación , Inmunohistoquímica , Isoenzimas/biosíntesis , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Microsomas Hepáticos/enzimología , Oxidorreductasas N-Desmetilantes/biosíntesis , Oxidorreductasas N-Desmetilantes/genética , Progesterona/metabolismo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Testosterona/metabolismoRESUMEN
A blue roan Percheron foal was born with poorly circumscribed patchy alopecia of the trunk and legs. Teeth and hoof development were normal. Alopecia was progressive, becoming almost complete by 1 year of age. Histopathological findings in a skin biopsy obtained at 7 months of age were consistent with severe follicular hypoplasia. Sebaceous glands, epitrichial sweat glands and arrector pilae muscles were normal. The horse is alive and otherwise well at 6 years of age, although adult stature is considered small for this breed. The clinical history and histopathological findings are most consistent with a form of congenital hypotrichosis.
Asunto(s)
Enfermedades de los Caballos/congénito , Enfermedades de los Caballos/diagnóstico , Hipotricosis/veterinaria , Animales , Diagnóstico Diferencial , Enfermedades de los Caballos/patología , Caballos , Hipotricosis/congénito , Hipotricosis/diagnóstico , Pierna , MasculinoRESUMEN
We have previously demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suppressed the induction of the costimulatory molecule CD86 (B7-2) on B220+ and Mac-1+ spleen cells following the injection of allogeneic P815 tumor cells. In this study, TCDD exposure was shown to suppress CD54 and major histocompatibility complex (MHC) class II expression on B220+, Mac-1+, and CD11c+ splenic antigen presenting cells (APC). Furthermore, interleukin-12 (IL-12) production by spleen cells from P815-immunized mice was significantly decreased following exposure to TCDD. To determine if exogenous costimulation could enhance the activation of APC, vehicle- and TCDD-treated mice were injected with an agonistic antibody to murine CD40. Stimulation with anti-CD40 increased the expression of CD86, CD54, and MHC class II on splenic APC and greatly enhanced the production of interleukin-12. TCDD treatment had minimal effects on the anti-CD40-induced expression of accessory molecules on splenic APC. TCDD exposure had no effect on anti-CD40-induced IL-12 in the plasma but suppressed its production from cultured spleen cells. Surprisingly, although stimulation via CD40 increased the activation of APC, allograft effector functions were not restored in TCDD-treated mice, perhaps due to persistent defects in antigen processing and presentation, cytokine production, T cell function, or CD40-independent pathways of APC activation.
Asunto(s)
Células Presentadoras de Antígenos/efectos de los fármacos , Antígenos CD40/efectos de los fármacos , Contaminantes Ambientales/toxicidad , Dibenzodioxinas Policloradas/toxicidad , Inmunología del Trasplante/efectos de los fármacos , Animales , Recuento de Células , Femenino , Citometría de Flujo , Indicadores y Reactivos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Tamaño de los Órganos , Fenotipo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Bazo/citología , Bazo/inmunología , Células Tumorales CultivadasRESUMEN
A 5-year-old Hereford cow was donated to Oregon State University, College of Veterinary Medicine. Two weeks before presentation the cow was treated by a left-flank laparotomy to correct a uterine torsion that revealed an excessive amount of abdominal fluid and a full term dead fetus. Ultrasonographic evaluation of the right cranioventral thoracic cavity was performed owing to physical examination (muffled heart sounds, areas of silence) and thoracocentesis findings suggestive of pleuritis. Ultrasonography revealed hypoechoic pleural effusion and a mass of mixed echogenicity visible within the right atrial lumen extending into the cranial vena cava. A diagnosis of cranial vena cava thrombosis was demonstrated at necropsy. The clinical, ultrasonographic, and pathological features of this less common condition (cranial vena cava thrombosis) in cattle are discussed.
Asunto(s)
Aspergilosis Broncopulmonar Alérgica/veterinaria , Enfermedades de los Bovinos/diagnóstico por imagen , Derrame Pleural/veterinaria , Neumonía/veterinaria , Trombosis/veterinaria , Vena Cava Superior , Animales , Aspergilosis Broncopulmonar Alérgica/complicaciones , Bovinos , Femenino , Derrame Pleural/diagnóstico por imagen , Derrame Pleural/etiología , Neumonía/complicaciones , Trombosis/diagnóstico por imagen , Trombosis/etiología , UltrasonografíaRESUMEN
The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of the Trask and Wilson rivers on the Oregon coast (n = 6) were infected by 5 species of helminths (100% prevalence). Single species of Eucestoda (Schistocephalus solidus), Digenea (Euparyphium inerme), Acanthocephala (Corynosoma strumosum), and 8 species of Nematoda (Strongyloides lutrae; larvae of Eustrongylides sp., Anisakis sp., and Contracaecum sp.; 3 of Cystidicolidae, and Hedruris sp.) were collected. Most species are typical of piscine definitive hosts and were present as incidental parasites of river otters. Notably, specimens of Euparyphium inerme are reported for the first time in river otters from North America; occurrence of other helminths constitutes new host or geographic records for parasites in river otters in Oregon and Washington. Parasites with marine life cycles were acquired by river otters in freshwater habitats at a great distance from the ocean. The helminth fauna of river otters in the Pacific Northwest was influenced primarily by ecological factors and was indicative of eclectic food habits and the relatively extensive home ranges occupied by these mustelids.
Asunto(s)
Helmintiasis Animal , Parasitosis Intestinales/veterinaria , Nutrias/parasitología , Acantocéfalos/aislamiento & purificación , Animales , Infecciones por Cestodos/epidemiología , Infecciones por Cestodos/veterinaria , Femenino , Agua Dulce , Helmintiasis/epidemiología , Parasitosis Intestinales/epidemiología , Masculino , Infecciones por Nematodos/epidemiología , Infecciones por Nematodos/veterinaria , Noroeste de Estados Unidos/epidemiología , Prevalencia , Infecciones por Trematodos/epidemiología , Infecciones por Trematodos/veterinariaRESUMEN
Pretreatment of mice with chlordecone (CD) reduced hepatic accumulation of a subsequent dose of [14C]CD without significantly changing [14C]CD biotransformation. To determine if CD-induced changes in hepatic [14C]CD accumulation were coincident with altered cell composition, we examined the effects of CD on hepatic protein and lipid content, on fatty acid profiles of liver and kidney, and on the ultrastructure of hepatocytes. SDS-polyacrylamide gel electrophoresis detected an apparent CD dose-related increase in a microsomal protein with a molecular weight of about 23 kDa. Total liver or kidney lipid contents were not altered by CD but relative amounts of several hepatic fatty acids were changed. CD caused marked hepatic mitochondrial swelling, increased amounts of endoplasmic reticulum, apparently increased numbers of peroxisome-like structures, and decreased numbers of lipid droplets in cytoplasm of hepatocytes. Numbers of lipid droplets were not decreased in perisinusoidal fat storage cells. In addition, the numbers of cytoplasmic lipoprotein vesicles were apparently increased in some hepatocytes. Overall these changes indicated an increased hepatocyte secretory activity and suggested that CD changed hepatocellular lipid transport, storage, and metabolism pathways.
Asunto(s)
Clordecona/toxicidad , Insecticidas/toxicidad , Metabolismo de los Lípidos , Hígado/efectos de los fármacos , Proteínas/metabolismo , Animales , Clordecona/farmacocinética , Electroforesis en Gel de Poliacrilamida , Insecticidas/farmacocinética , Hígado/metabolismo , Hígado/ultraestructura , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Electrónica , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/metabolismoRESUMEN
Megaesophagus was diagnosed in 15 llamas on the basis of survey and contrast radiography. Age of onset ranged from 13 months to 9.5 years. Clinical signs varied, with salivation being the most common; regurgitation or dysphagia were noted in only 33% of the cases. Duration of the disorder ranged from 1 week to 5 years. Organophosphate toxicity was the cause of megaesophagus in 1 llama. While most cases were of unknown etiology, the 3 with histological abnormalities included 1 with vagal neuropathy and 2 with a degenerative myopathy of esophageal muscles. The causes in most were undetermined.
Asunto(s)
Camélidos del Nuevo Mundo , Acalasia del Esófago/veterinaria , Animales , Acalasia del Esófago/diagnóstico por imagen , Acalasia del Esófago/etiología , Femenino , Masculino , Radiografía , Estudios RetrospectivosRESUMEN
An epidemic of photosensitization was observed in a group of lambs on irrigated autumn pasture in western Oregon. Signs included crusting, necrosis, and sloughing of the skin over the nostrils, lips, and ears, and of the mucous membranes of the buccal regions. Microscopic examination of plant material from the pasture disclosed spores of Pithomyces chartarum. This fungus has been documented as a causal factor in photosensitization in sheep and cattle (facial eczema) in other parts of the world. An infective agent or other plant material that could have induced the clinical signs in the lambs was not evident. Weather and humidity conditions were ideal for fungal growth during the grazing period, and the fungus was detected in large numbers before and during the epidemic. Even though facial eczema has not been reported previously in northwestern United States, we feel the circumstances surrounding this epidemic warrant such a diagnosis.
Asunto(s)
Dermatosis Facial/veterinaria , Lolium/microbiología , Hongos Mitospóricos , Trastornos por Fotosensibilidad/veterinaria , Enfermedades de las Ovejas/microbiología , Animales , Eccema/microbiología , Eccema/veterinaria , Cara , Dermatosis Facial/microbiología , Femenino , Hígado/patología , Masculino , Trastornos por Fotosensibilidad/microbiología , Ovinos , Piel/patología , Esporas FúngicasRESUMEN
Hemochromatosis, an iron storage disease, was diagnosed in 3 horses with hepatic cirrhosis. Each horse had bridging portal fibrosis and abundant iron deposits in the cytoplasm of hepatocytes. Serum concentrations of liver-derived enzymes and total bile acids were high. However, serum iron concentration was not high, and iron binding capacity was only 46% saturated in the 1 horse in which it was measured. However, the concentration of iron in the liver of this horse was 20 times the reference limits. Hemochromatosis is common in mynah birds and human beings. There are several types of this iron storage disease. In human beings, there is a familial disease with iron absorption inappropriate for the level of stored iron. Hemochromatosis also occurs secondary to cirrhosis of the liver, and in certain anemia diseases. Another type of hemochromatosis is seen in association with dietary iron overload. These horses were not related, and there was not any evidence of high dietary iron intake.
Asunto(s)
Hemocromatosis/veterinaria , Enfermedades de los Caballos , Cirrosis Hepática/veterinaria , Animales , Femenino , Hemocromatosis/complicaciones , Hemocromatosis/patología , Enfermedades de los Caballos/patología , Caballos , Hierro/análisis , Hígado/química , Hígado/patología , Cirrosis Hepática/complicaciones , Cirrosis Hepática/patología , MasculinoRESUMEN
Tissue disruption methods were developed and serum-free cell culture media formulated for the maintenance in vitro of cells from juvenile worms (day 18 after infection) of Schistosoma mansoni. Cultures maintained viability for up to 6 mo when plated on a feeder layer of irradiated rat liver cells and survived primarily as clusters of small (2.5-4 microns diameter) cells with a high nuclear-to-cytoplasmic ratio and relatively few organelles identified by electron microscopy. Cultures synthesized a protein profile similar to that of intact worms, and the cell clusters maintained a time- and concentration-dependent contractile response to serotonin. Cells synthesizing DNA were detected by precursor incorporation and flow cytometry in cultures initially and also after several weeks in vitro, although the percentage of cells synthesizing DNA decreased with time. Efforts to identify peptide growth factor-responsive tyrosine phosphorylation were negative, and the overall amount of S. mansoni phosphotyrosine-containing proteins identified by western blot with anti-phosphotyrosine monoclonal antibody was much less than that found in a peptide growth factor-responsive mouse cell line.
Asunto(s)
Schistosoma mansoni/crecimiento & desarrollo , Animales , Western Blotting , Adhesión Celular , Línea Celular , Medio de Cultivo Libre de Suero , ADN/biosíntesis , Factor de Crecimiento Epidérmico/farmacología , Citometría de Flujo , Proteínas del Helminto/biosíntesis , Concentración de Iones de Hidrógeno , Masculino , Ratones , Microscopía Electrónica , Fosforilación/efectos de los fármacos , Ratas , Schistosoma mansoni/citología , Schistosoma mansoni/ultraestructuraRESUMEN
Sporulated oocysts (mean dimensions = 13.0 x 10.8 microns) and sporocysts (11.3 x 5.5 microns) of a coccidian resembling Frenkelia sp. or Sarcocystis sp. were present in the lamina propria of the small intestine of a naturally-infected northern spotted owl (Strix occidentalis caurina) collected near Medford, Oregon (USA). Dimensions of these oocytes and sporocysts appear to be considerably smaller than those from other sarcocystid species with avian definitive hosts. Additionally, numerous developmental stages and unsporulated oocysts (mean dimensions 22.8 x 17.8 microns) of a possible species of Isospora also were observed in the intestinal epithelium. This constitutes the first report of enteric coccidia from spotted owls. Neither parasite appeared to cause the death of the bird.
Asunto(s)
Enfermedades de las Aves/parasitología , Coccidios/aislamiento & purificación , Coccidiosis/veterinaria , Parasitosis Intestinales/veterinaria , Intestino Delgado/parasitología , Animales , Aves , Coccidiosis/parasitología , Femenino , Parasitosis Intestinales/parasitologíaAsunto(s)
Aluminio/envenenamiento , Enfermedades de los Bovinos/etiología , Cobre/deficiencia , Encefalomalacia/veterinaria , Manganeso/deficiencia , Animales , Encéfalo/patología , Química Encefálica , Cruzamiento , Bovinos , Encefalomalacia/etiología , Riñón/química , Hígado/química , Masculino , Médula Espinal/patologíaRESUMEN
Serum-free mouse embryo (SFME) cells, derived in medium in which serum is replaced with growth factors and other supplements, are proastroblasts that are acutely dependent on epidermal growth factor (EGF) for survival. Ultrastructurally, an early change found in SFME cells deprived of EGF was a loss of polysomes which sedimentation analysis confirmed to be a shift from polysomes to monosomes. The ribosomal shift was not accompanied by decreased steady-state level of cytoplasmic actin mRNA examined as an indicator of cellular mRNA level. With time the cells became small and severely degenerate and exhibited nuclear morphology characteristic of apoptosis. Genomic DNA isolated from cultures undergoing EGF deprivation-dependent cell death exhibited a pattern of fragmentation resulting from endonuclease activation characteristic of cells undergoing apoptosis or programmed cell death. Flow cytometric analysis indicated that cultures in the absence of EGF contained almost exclusively G1-phase cells. Some of the phenomena associated with EGF deprivation of SFME cells are similar to those observed upon NGF deprivation of nerve cells in culture, suggesting that these neuroectodermal-derived cell types share common mechanisms of proliferative control involving peptide growth factor-dependent survival.
Asunto(s)
Astrocitos/citología , Factor de Crecimiento Epidérmico/farmacología , Animales , Astrocitos/química , Astrocitos/ultraestructura , Sangre , Núcleo Celular/ultraestructura , Supervivencia Celular , Células Cultivadas , Medios de Cultivo , Citoplasma/ultraestructura , ADN/análisis , Embrión de Mamíferos , Fase G1 , L-Lactato Deshidrogenasa/metabolismo , Ratones , Microscopía Electrónica , Polirribosomas/ultraestructura , ARN Mensajero/análisisRESUMEN
One hundred fifty Se-deficient, pregnant, crossbred beef cows were assigned to 1 of 4 treatment groups: group A, Se-deficient control; group B, 1 Se bolus at 0 and 119 days; group C, 1 Se bolus at 0 days; and group D, 2 Se pellets at 0 days. The Se bolus is an osmotic pump designed to release 3 mg of Se/d into the reticulorumen. The Se pellets weight approximately 30 g and contain 10% elemental Se, which is liberated in the reticulorumen. The Se bolus is designed to provide Se supplementation for 120 days and the Se pellets provide supplementation for up to 18 months. Cattle were maintained on Se-deficient pasture or forages prepared from these pastures for the duration of the experiment. Blood samples were collected from cows prior to treatment (time 0) and at 28, 52, 119, and 220 days thereafter and analyzed for blood Se (BSe) concentration. Body weights were recorded at each sampling time. Blood Se concentration of cows from all supplemented groups were significantly (P less than 0.01) higher than control values at all sample dates after treatments began. By the end of the 220-day study, treatment group-B cattle had significantly (P less than 0.01) higher BSe concentrations than any other group. Body weights of treatment groups fluctuated throughout the study, but did not differ (P greater than 0.05) between groups. One cow and 6 calves born to cows during the experimental period died. Necropsy of 5 calves provided no evidence linking these deaths to treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Bovinos/sangre , Calostro/metabolismo , Placenta/metabolismo , Selenio/administración & dosificación , Animales , Preparaciones de Acción Retardada , Evaluación de Medicamentos/veterinaria , Femenino , Intercambio Materno-Fetal , Embarazo , Distribución Aleatoria , Factores de Riesgo , Selenio/deficiencia , Selenio/metabolismo , Factores de TiempoRESUMEN
In a sheep flock, Chlamydia psittaci, Campylobacter fetus, Ca jejuni, and Salmonella dublin caused abortions. A vaccine that contained C psittaci type I from 2 sources: a cow with pneumonia and an aborted ovine fetus, Ca fetus, Ca jejuni, and 4 strains of K99 Escherichia coli was given to 240 ewes before they were bred. All fetuses, placentas, and lambs, that died within 36 hours of birth were examined for infectious agents. Of 55 abortions, 30 (55%) were caused by Chlamydia or Campylobacter spp; 25 of the 30 (83%) abortions took place in the nonvaccinated group (n = 240). Forty-five more lambs survived in the vaccinated group than in the nonvaccinated group. Abortion rates for Chlamydia and Campylobacter spp (2.1 vs 10.4% in vaccinated and nonvaccinated groups, respectively) were significantly different (P = 0.003). Abortion rates for S dublin were not significantly different between groups. The Salmonella epizootic was controlled quickly by sanitation and treatment procedures. The vaccine was at least 80% efficacious against Chlamydia and Campylobacter spp and appeared to be protective.
Asunto(s)
Aborto Veterinario/prevención & control , Vacunas Bacterianas , Infecciones por Campylobacter/veterinaria , Psitacosis/veterinaria , Enfermedades de las Ovejas/prevención & control , Animales , Infecciones por Campylobacter/prevención & control , Campylobacter fetus/inmunología , Chlamydophila psittaci/inmunología , Escherichia coli/inmunología , Femenino , Embarazo , Psitacosis/prevención & control , Ovinos , Vacunación/veterinariaRESUMEN
An immunohistochemical technique was used to localize the major constitutive cytochrome P450 isozyme, P450 LM2, and the major beta-naphthoflavone-inducible isozyme, P450 LM4b, in the livers of untreated and aflatoxin B1 (AFB1)-initiated, tumor-bearing rainbow trout. In hepatic tissue sections from untreated trout, no regular anatomical pattern within the hepatic parenchymal cells could be discerned for either isozyme. Immunostaining was observed for P450 LM2 along the sinusoidal border of some of the parenchymal cells, there was moderate staining within the cytoplasm of most cells, and there were focal areas of increased staining. There was intense, uniform immunostaining for P450 LM2 within the cytoplasm of the bile duct cells, in the endothelial lining of arterioles, and along the epithelial surface of the gall bladder. Staining for P450 LM4b in livers from untreated trout was barely detectable. In liver tissue sections from AFB1-treated tumor-bearing fish, P450 LM2 appeared to be reduced and P450 LM4b was absent in the hepatocellular carcinoma nodules. An apparent increase in immunostaining for P450 LM4b was observed in nonneoplastic cells juxtaposed next to neoplastic cells as well as in areas distant to the tumors. These results may indicate that the pattern of P450 isozymes is altered in nonneoplastic cells of tumor-bearing trout livers.
Asunto(s)
Sistema Enzimático del Citocromo P-450/análisis , Isoenzimas/análisis , Neoplasias Hepáticas/enzimología , Hígado/enzimología , Animales , Técnicas para Inmunoenzimas , Inmunohistoquímica , Distribución Aleatoria , TruchaRESUMEN
Helminth parasites are reported for the first time from northern spotted owls. Seventy-one percent of a sample of Strix occidentalis caurina from western Oregon was infected. Nematodes (Porrocaecum depressum, Capillaria falconis, Microtetrameres sp. and Synhimantus hamatus) were the most prevalent parasites although cestodes (Paruterina rauschi) and acanthocephalans (Centrorhynchus conspectus) were also represented. There was an association between components of this helminth fauna and the diet of spotted owls which is dominated by small rodents. The occurrence of P. rauschi rather than P. candelabraria in this geographic region and host-species may provide additional support for recognition of a parapatric distribution in the ranges of Paruterina spp. among strigiforms in the Nearctic.
Asunto(s)
Enfermedades de las Aves/parasitología , Helmintiasis Animal , Helmintos/aislamiento & purificación , Acantocéfalos/aislamiento & purificación , Animales , Aves , Cestodos/aislamiento & purificación , Infecciones por Cestodos/epidemiología , Infecciones por Cestodos/parasitología , Infecciones por Cestodos/veterinaria , Femenino , Helmintiasis/epidemiología , Helmintiasis/parasitología , Masculino , Nematodos/aislamiento & purificación , Infecciones por Nematodos/epidemiología , Infecciones por Nematodos/parasitología , Infecciones por Nematodos/veterinaria , OregonRESUMEN
The immunotoxic properties of two experimental antiallergic drugs, CI-949 and CI-959, were investigated. Wistar rats were gavaged once (CI-949) or twice (CI-959) daily for 21 days with the drugs. Immunotoxicity was assessed using the enzyme-linked immunoabsorbant assay (ELISA) for humoral immunity, a delayed-type hypersensitivity (DTH) procedure for cell-mediated immunity, and natural killer cell (NKC) activity to evaluate spontaneous cytotoxicity. Ratios of body weight to spleen, thymus, liver and kidney weights were determined. Routine histopathology was performed on lymphoid tissue and other body organs. Although 100 mg/kg/day of CI-949 had some stimulating effect on antibody production and NKC cytotoxicity, no consistent immunomodulation was apparent. Except for a significant increase in liver weight at the 100 mg/kg dose of CI-949, no other toxic effects were observed. In contrast to CI-949, CI-959 significantly (P less than 0.05) suppressed antibody production at the 100 mg/kg dose and impaired the DTH reaction, although not significantly. Natural killer cell cytotoxicity was unaffected by 100 mg/kg CI-959. Decreased body weight and histopathological lesions were observed in the thymus and spleen of rats administered 100 mg/kg CI-959. These lesions ranged from mild to severe lymphoid depletion which was also reflected in significantly (P less than 0.05) reduced spleen and thymus organ weight to body weight ratios. Since 100 mg/kg of CI-959 produced toxicological and pathological alterations in the exposed rats, these data suggest that CI-959 is not highly or specifically immunotoxic at dosages lower than those that alter conventional toxicological parameters used in new drug testing programs.(ABSTRACT TRUNCATED AT 250 WORDS)