Correlates to survival of juvenile sea otters in Prince William Sound, Alaska, 1992–1993

We estimated survival of sea otters (Enhydra lutris) for 1 year post weaning during 1992–1993 in Prince William Sound (PWS), location of the 1989 Exxon Valdez oil spill. We sampled 38 pups in eastern PWS (EPWS), an unoiled area occupied by sea otters for <15 years, and 33 pups from oiled western PWS (WPWS), occupied for >25 years. We compared survival between areas, sexes, and condition groups. We also examined the relation of blood parameters to survival. Survival was estimated at 0.74 in EPWS and 0.52 in WPWS. Female survival was 0.86 in EPWS and 0.64 in WPWS, whereas male survival was lower, 0.61 in EPWS and 0.44 in WPWS. Sea otters from EPWS were in better condition (mass/length) than WPWS sea otters. Pups in better condition had higher survival in EPWS but not in WPWS. Foraging success was greater in EPWS than in WPWS, consistent with either an effect of length of occupation or the effects of oil on the prey base or a combination of these effects. Area differences in blood parameters suggested liver damage in WPWS sea otters, perhaps resulting from continued exposure to oil. Thus, both length of occupation and oiling history likely influenced juvenile survival in PWS.

Specific biological effects of an anti-rat PMN antiserum intraperitoneally infected into f344/n rats

Neutropenia can be produced with antimitotic chemicals, but this method lacks specificity. An alternative is to use antibody-dependent cytotoxicity to produce neutropenia; however, this method has not been completely evaluated with respect to efficacy, specificity, and potential collateral damage, especially to constituents of bone marrow. This study used in vitro and in vivo methods to evaluate specific biological effects of a commercially available rabbit anti-rat neutrophil (PMN) antiserum in F344/N rats. The viability of rat pulmonary alveolar macrophages (PAMs), PMNs, and lymphocytes in vitro was quantified using a trypan blue dye exclusion test. Amounts of antiserum in vitro that rendered PMNs 100% nonviable did not decrease the viability or phagocytic ability of the PAMs and did not decrease the viability of the lymphocytes. Intraperitoneal (IP) injection of the antiserum into rats resulted in complete depletion of the PMNs and about a 50% depletion of the lymphocytes in circulating blood within 24 hours. The numbers of both cell types remained lowered for 5 days, but returned to control values by Day 6 after the IP injection. The antiserum had no effect on the numbers of PAMs or lymphocytes in the pulmonary alveolar airspaces, as determined by quantifying the numbers of these cell types in bronchoalveolar lavage fluid (BALF). The numbers of PMNs in BALF, however, decreased on Days 3 and 4 after IP injection of antiserum, but were not different from control values by Day 5. The viability of the PAMs in BALF of treated rats was not different from control values at any time point. There were no morphological indications that the injected antiserum damaged lung tissue or stem cells in bone marrow. Results demonstrate that the anti-rat PMN antiserum administered IP to F344/N rats depletes circulating PMNs and partially depletes lymphocytes for a period of about 6 days without adversely affecting the precursors of red or white blood cells in bone marrow. We concluded that the antiserum is a relatively specific way to temporarily render rats neutropenic without damaging precursor cells in bone marrow.

Methodologic considerations for the use of canine in vivo aged biotinylated erythrocytes to study RBC senescence

Biotinylation of erythrocytes has been developed in rabbits as a tool to retrieve labeled cells following various periods in circulation. This retrieval capability allows biochemical studies to be conducted on red blood cells (RBC) that have aged for desired times in vivo. However, because erythrocyte life span is much shorter in rabbits than in humans, and because cell removal is measurably age-independent in rabbits, we have sought to validate the same protocol in dogs, whose cell life span and age-dependent removal characteristics are similar to humans'. Canine RBC were biotinylated in vivo by infusion of N-hydroxysuccinimidyl biotin dissolved in dimethylacetamide or dimethylsulfoxide. Cell life spans were evaluated using 14C-cyanate labeling followed by scintillation counting or avidin-FITC labeling followed by flow cytometry. Both methods gave identical results. The life span of the biotin-conjugated cells was found to be normal (approximately 110 days), and the stability of the biotin ligand was adequate for efficient retrieval of cells using avidin-coated magnetic beads (magnetic cell sorting [MACS]). From each isolation, approximately 20 microL of packed biotinylated cells of approximately 90% purity (i.e., 10% contamination by unlabeled cells) could be harvested. On average, approximately 60% of the biotinylated cells in any sample could be retrieved. Either multiple isolations or use of larger collection columns will facilitate collection of cell numbers sufficient for biochemical tests. After incorporating several modifications in the previous biotinylation protocol that were required for adaptation to the dog, the methodology can be used to study red cell senescence in an animal that has several pertinent similarities to humans.

Clinical and clinical laboratory correlates in sea otters dying unexpectedly in rehabilitation centers following the Exxon Valdez oil spill

Following the Exxon Valdez oil spill, 347 oiled sea otters (Enhydra lutris) were treated in rehabilitation centers. Of these, 116 died, 94 within 10 days of presentation. Clinical records of 21 otters dying during the first 10 days of rehabilitation were reviewed to define the laboratory abnormalities and clinical syndromes associated with these unexpected deaths. The most common terminal syndrome was shock characterized by hypothermia, lethargy, and often hemorrhagic diarrhea. In heavily and moderately oiled otters, shock developed within 48 hours of initial presentation, whereas in lightly oiled otters shock generally occurred during the second week of captivity. Accompanying laboratory abnormalities included leukopenia with increased numbers of immature neutrophils (degenerative left shift), lymphopenia, anemia, azotemia (primarily prerenal), hyperkalemia, hypoproteinemia/hypoalbuminemia, elevations of serum transaminases, and hypoglycemia. Shock associated with hemorrhagic diarrhea probably occurred either as a direct primary effect of oiling or as an indirect effect secondary to confinement and handling in the rehabilitation centers. Lightly oiled otters were less likely to die from shock than were heavily oiled otters (22% vs. 72%, respectively). Heavily oiled otters developed shock more rapidly and had greater numbers of laboratory abnormalities, suggesting that exposure to oil was an important contributing factor.

Clinical pathology and hemostatic abnormalities in experimental African horsesickness

Infection of naive North American horses with 10(4) cell culture infectious doses (CCID50) of virulence variants of African horsesickness virus (AHSV), designated AHSV/4SP, AHSV/9PI, and AHSV/4PI, reproduced three classical forms of African horsesickness: acute (pulmonary), subacute (cardiac), and febrile, respectively. Distinct clinicopathologic and hemostatic abnormalities were associated with each form of disease. Hemostatic abnormalities included increased concentration of fibrin degradation products and prolongation of prothrombin, activated partial thromboplastin, and thrombin clotting times. Hemostatic findings indicated activation of the coagulation and fibrinolytic systems with clotting factor consumption in acute and subacute cases of African horsesickness. Hematologic abnormalities in acute and subacute cases of African horsesickness included leukopenia, decreased platelet counts, elevated hematocrit, and increased erythrocyte counts and hemoglobin concentration. Leukopenia was characterized by lymphopenia, neutropenia, and a left shift. Increased levels of serum creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and alkaline phosphatase, hypocalcemia, hypoalbuminemia, hypoproteinemia, and elevated creatinine, phosphorus, and total bilirubin levels were present in some but not all horses. Metabolic acidosis, indicated by decreased total bicarbonate and increased lactate and anion gap, was present in horses with the acute form of disease. Mild thrombocytopenia and leukopenia were occasionally associated with the febrile form of disease. These results suggest a role for intravascular coagulation in the pathogenesis of African horsesickness.

Expression of transforming growth factor alpha and epidermal growth factor receptor in rat lung neoplasms induced by plutonium-239

Ninety-two rat lung proliferative lesions and neoplasms induced by inhaled 239PuO2 were evaluated for aberrant expression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor receptor (EGFR). Expression of TGF-alpha protein, measured by immunohistochemistry, was higher in 94% of the squamous cell carcinomas and 87% of the foci of alveolar epithelial squamous metaplasia than that exhibited by the normal-appearing, adjacent lung parenchyma. In contrast, only 20% of adenocarcinomas and foci of epithelial hyperplasia expressed elevated levels of TGF-alpha. Many neoplasms expressing TGF-alpha also expressed excessive levels of EGFR mRNA. Southern and DNA slot blot analyses showed that the elevated EGFR expression was not due to amplification of the EGFR gene. These data suggest that increased amounts of TGF-alpha were early alterations in the progression of plutonium-induced squamous cell carcinoma, and these increases may occur in parallel with overexpression of the receptor for this growth factor. Together, these alterations create a potential autocrine loop for sustaining clonal expansion of cells initiated by high-LET radiation.

Plutonium-induced proliferative lesions and pulmonary epithelial neoplasms in the rat: immunohistochemical and ultrastructural evidence for their origin from type II pneumocytes

Immunohistochemistry and transmission electron microscopy were used to clarify the cellular origin for plutonium-239-induced pulmonary proliferative (preneoplastic) epithelial lesions and epithelial neoplasms in F344 rats. Examples of each histologic type of proliferative lesion and neoplasm were stained by the avidin-biotin complex immunoperoxidase method using antibodies to rat surfactant apoprotein and Clara cell antigen. Rat surfactant apoprotein immunostaining was detected in type II pneumocytes in sections of normal lung, in the cells of the proliferative lesions classified histologically as alveolar epithelial hyperplasia (51) and mixed foci (alveolar epithelial hyperplasia with fibrosis) (30), and in adenomas (2), adenocarcinomas (3), and adenosquamous carcinomas (2). With the exception of one adenosquamous carcinoma, Clara cell antigen immunostaining was not detected in any of the pulmonary lesions but was detected in nonciliated cuboidal epithelial (Clara) cells in normal bronchioles. The epithelial cells of the proliferative lesions and neoplasms had ultrastructural features consistent with type II pneumocytes, i.e., the presence of cytoplasmic lamellar and multivesicular bodies. The results of these studies indicate that the majority of plutonium-induced proliferative epithelial lesions and neoplasms in the rat originate from alveolar type II pneumocytes.

Senescence of canine biotinylated erythrocytes: increased autologous immunoglobulin binding occurs on erythrocytes aged in vivo for 104 to 110 days

We have evaluated senescence related changes in canine red blood cells (RBCs) using the biotinylation system, where RBCs are labeled in vivo with biotin at the beginning of their life span, and retrieved from circulation on immobilized avidin at the end of their life span. This approach avoids the controversial use of density gradient centrifugation to collect presumably old RBCs. Furthermore, the dog is an appropriate model for human RBC senescence because it has a low degree of random RBC loss and a similarly long RBC life span (approximately 110 days). Two dogs had 97% to 100% of their circulating RBCs biotinylated by infusion of N-hydroxysuccinimido biotin (Clontech, Palo Alto, CA; Calbiochem, La Jolla, CA) dissolved in dimethyl sulfoxide. At postbiotinylation days 104 and 107 for one dog and day 110 for the other dog, biotinylated RBCs were isolated by magnetic cell sorting and analyzed for the presence of autologous IgG using 125I-labeled sheep-antidog IgG (SAD IgG). On all 3 days, there were at least three times more SAD IgG molecules per RBC on senescent biotinylated RBCs than on control (unfractionated) RBCs (day 104: 11,677 v 3,399; day 107: 6,710 v 2,115; day 110: 6,042 v 1,838 molecules of SAD IgG per senescent v control RBC). Furthermore, it is unlikely that an immune response to the conjugated biotin had been elicited, because fresh in vitro biotinylated RBCs that were incubated in autologous plasma (taken after exposure to circulating biotinylated RBCs for 113 days) and then exposed to the SAD IgG showed no increase in antibody binding over control (non-biotinylated) RBCs (1,431 v 1,378 cpm/10(8) biotinylated v control RBCs; P > .20). These results suggest that senescence of canine biotinylated RBCs is characterized by binding of autologous IgG and that antibiotin antibodies do not contribute to this process.

Ultracentrifugal and electrophoretic characteristics of the plasma lipoproteins of miniature schnauzer dogs with idiopathic hyperlipoproteinemia

To better characterize the idiopathic hyperlipoproteinemia of Miniature Schnauzer dogs, the plasma lipoproteins of 20 Miniature Schnauzers (MS) and 11 dogs of other breeds (DOB) were evaluated by ultracentrifugation, electrophoresis, and biochemical tests. Seventeen MS were healthy; 3 had diabetes mellitus. Plasma from 6 of 17 healthy and all 3 diabetic MS was visibly lipemic. Lipemia was slight to marked in healthy lipemic MS, and marked in diabetic ones. All DOB had clear plasma; 8 were healthy and 3 had diabetes. All healthy lipemic MS and diabetic lipemic MS had hypertriglyceridemia associated with excess very low density lipoproteins. Chylomicronemia was present in 4 of 6 healthy lipemic MS and all 3 diabetic lipemic MS. Lipoproteins with ultracentrifugal and electrophoretic characteristics of normal low density lipoprotein were lacking in 4 of 6 healthy lipemic MS. The lipoprotein patterns of 4 of 11 healthy nonlipemic MS were characterized by mild hypertriglyceridemia associated with increased very low density lipoproteins and a lack of lipoproteins with characteristics of normal low density lipoproteins. Lipoprotein patterns of diabetic DOB closely resembled those of healthy DOB; those of diabetic lipemic MS resembled those of markedly lipemic healthy lipemic MS. In conclusion, the hyperlipoproteinemia of Miniature Schnauzers is characterized by increased very low density lipoproteins with or without accompanying chylomicronemia; some affected dogs may have decreased low density lipoproteins.

Sequential analysis of the pathogenesis of plutonium-induced pulmonary neoplasms in the rat: morphology, morphometry, and cytokinetics

Light microscopy, morphometry, and cytokinetic techniques were used to examine the dynamics of plutonium-induced pulmonary proliferative lesions and neoplasms in rats at several intervals to 450 days after inhalation exposure to aerosols of 239PuO2. Maximal increases in alveolar and bronchiolar epithelial cell labeling were seen at 30 days; decreasing subsequently, the levels remained elevated above control indices. Focal proliferative epithelial lesions developed in the lung by 180 days and before the onset of pulmonary neoplasms. Pulmonary neoplasms, predominantly adenocarcinomas and squamous cell carcinomas, were initially observed at 308 days. The proliferative lesions progressed through a succession of morphological changes leading to the development of neoplasms. The volume density (fraction) and epithelial surface area of foci of alveolar epithelial hyperplasia increased progressively between 180 and 450 days after exposure, in contrast to the other proliferative lesions. We conclude that plutonium-induced pulmonary neoplasms develop through a succession of focal proliferative lesions that represent developmental preneoplastic lesions. Progressive increases in volume and epithelial surface area of the alveolar epithelial hyperplasias suggest that they may be more at risk for neoplastic transformation than the other histological types of proliferative foci.

General responses of the bone marrow to injury

Hematologic responses in a toxicologic setting may be quite complex and may involve both local as well as systemic manifestations of toxicity and/or pharmacologic responses. Direct toxicity to bone marrow can lead to changes such as marrow necrosis, marrow dysplasia, and macrophage hyperplasia. Some toxic compounds can directly stimulate or suppress the development of 1 or more marrow cell lines. The marrow may also respond to injury at distant sites with increased production of various blood cell elements. Accurate interpretation of hematologic responses generally involves integration of peripheral blood data with bone marrow findings as well as toxicologic findings in other organ systems. This manuscript overviews the various marrow changes encountered in toxicologic studies and provides a perspective of how these changes are best approached from an interpretive viewpoint.

Cytologic evaluation of the respiratory tract

Evaluation of respiratory tract disease is a challenge for several reasons: no serum biochemical or hematologic tests that localize injury to the respiratory system are available, imaging techniques do not usually lead to etiologic diagnoses, and excisional biopsies are often very difficult to obtain from respiratory lesions. For these reasons, specific diagnosis of respiratory tract disease often resides in cytologic evaluation. This article reviews the various cytologic collection techniques that yield high-quality specimens from the upper and lower respiratory tract. Cytologic features of the normal respiratory tract as well as common respiratory disorders are described and illustrated.

Cellular immune responses in pigs fed a vitamin E- and selenium-deficient diet

The effects of dietary restriction of vitamin E (Vit E) and selenium (Se) on lymphocyte proliferation, natural killer (NK) cell activity, antibody-dependent cell-mediated cytotoxicity (ADCC), and on burst respiratory response of stimulated granulocytes as measured by chemiluminescence (CL) were studied in pigs. Six male weanling pigs were maintained for 25 d on a torula yeast-based diet containing no measurable amount of alpha-tocopherol and less than .02 mg of Se per kilogram of feed. Six others received the same basal diet supplemented with 33 IU of DL-alpha-tocopheryl acetate and .2 mg of Se per kilogram of feed. All pigs were inoculated with Salmonella typhisuis on d 21 of the feeding period and killed on d 25. Tests to measure cellular immune functions were performed on cells isolated from blood samples taken on d 21 and 25. After 21 d of feeding, lymphocyte blastogenesis responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen in pigs fed the Vit E- and Se-deficient diet were normal compared with the response in pigs fed the supplemented diet. Moreover, the cytotoxic activity of NK cells, the ADCC response, and the CL response of granulocytes were not affected. After 25 d, a marked suppression of lymphocyte response to mitogens occurred in pigs fed the Vit E- and Se-deficient diet when the cells were cultured in the presence of autologous serum. When fetal bovine serum replaced autologous serum in the cultures, no suppression was observed. No effect on NK activity and ADCC was observed, whereas the CL peak response of granulocytes tended to be higher in pigs fed the deficient diet.(ABSTRACT TRUNCATED AT 250 WORDS)

The molecular progression of plutonium-239-induced rat lung carcinogenesis: Ki-ras expression and activation

Specific, transforming point mutations of ras and alterations in ras expression have been associated with many neoplastic processes, and their presence may be pivotal in neoplastic transformation. Our objective were to evaluate the molecular and genetic alterations of Ki-ras in preneoplastic foci and neoplasms in the lungs of rats that inhaled 239PuO2 aerosols. Histologically classified pulmonary lesions were evaluated by in vitro nucleic acid amplification, oligonucleotide hybridization, and direct nucleic acid sequencing for activating Ki-ras point mutations. We evaluated ras expression in similar lesions using immunohistochemistry and in situ hybridization. Specific Ki-ras point mutations were present in 46% of the radiation-induced malignant neoplasms. Spontaneous pulmonary neoplasms, which are rare in rats, had similar activating mutations and frequencies (40%). We found similar mutation frequencies in radiation-induced adenomas and foci of alveolar epithelial hyperplasia. No mutations were identified in normal lung tissue. Ras expression in hyperplastic lesions and neoplasms was similar to that observed in normal pulmonary epithelia. These findings suggest that Ki-ras activation, not alterations in expression, is an early lesion associated with many radiation-induced, proliferative pulmonary lesions and that this molecular alteration may be an important component of both radiation-induced and spontaneous pulmonary carcinogenesis in the rat.

Optimization of the under-agarose assay of porcine neutrophil migration

Important procedural factors in the under-agarose assay for porcine neutrophil migration were identified, and optimal conditions were established. Three factors were tested: the concentration of zymosan-activated serum inoculated into the outer well; the number of neutrophils inoculated into the center well; and the time of incubation of the agarose plates. All factors had a significant (P less than 0.0001, 0.0001, and 0.01, respectively) effect on the chemotactic index of porcine neutrophils. The optimal combination of these 3 factors was undiluted zymosan-activated serum as the chemoattractant, 8 X 10(5) neutrophils inoculated into the center well, and 5 hours of incubation. The assay was validated, using standard conditions, and the data were used to predict the number of pigs and/or repetitive assays needed to identify differences among experimental groups.

Effects of repeated inhalation exposures to 1-nitropyrene, benzo[a]pyrene, Ga2O3 particles, and SO2 alone and in combinations on particle clearance, bronchoalveolar lavage fluid composition, and histopathology

The toxicities of 1-nitropyrene (NP) and benzo[a]pyrene (BaP), inhaled alone and in combination with particles and an irritant gas, were examined to evaluate synergisms among the organic compounds, particles, and gas. Groups of F344 rats were exposed 2 h/d, 5 d/wk for 4 wk to atmospheres of pure NP aerosol (7.5 mg/m3), and to these same compounds adsorbed to Ga2O3 particles (27 mg/m3) both with and without coexposure to 5 ppm SO2. Rats were also exposed to Ga2O3 and SO2 alone. Measurements were made of lung burdens of Ga2O3 particles and retention of radiolabeled tracer particles after the cessation of exposure to evaluate effects on particle clearance. Bronchoalveolar lavage fluid was analyzed to assess inflammation and cytotoxicity. Histopathology was examined to assess the nature and extent of lung injury. Particle clearance was significantly impaired (p less than .05) in all groups whose exposure atmosphere included Ga2O3, but was not significantly changed in the other exposure groups.

Bronchoalveolar lavage cytology in cynomolgus monkeys and identification of cytologic alterations following sequential saline lavage

Total and differential cell counts were determined on cytolytic specimens obtained by fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) of five normal cynomolgus monkeys. Total nucleated cell counts ranged from 100 to 430 cells/microliters. Macrophages were approximately 91% of total nucleated cells, while lymphocytes were 3%, neutrophils 4%, and eosinophils 2% of the initial BAL from each monkey. Less than 1% of the cells were mast cells and ciliated or nonciliated epithelial cells. The effects of repeated saline BAL on pulmonary cell populations were evaluated. Saline lavage of individual lung lobes resulted in a marked rise in circulating blood neutrophils at 4 hr after BAL; there was a similar rise in neutrophils in lavage fluids 24 hr after the initial lavage. Differential and total cell counts of both blood and lavage fluid returned to normal if subsequent lavages were spaced at 48-hr intervals. Lymphocytes were not present in saline-lavaged lung lobes, and protein levels of lavage fluids did not rise significantly. BAL produced a transient, reversible, intra-alveolar influx of neutrophils which was preceded by mobilization of bone marrow-stored neutrophils. Neutrophilia in the lavage fluid and blood was not detectable if lavage and blood sampling procedures were done at 48-hr intervals (which did not alter Ia antigen expression among BAL cells). These observations indicate that BAL is a valid method for sampling and assessing pulmonary cellular and fluid constituents if the procedures are done at intervals of at least 48 hr.

Rubratoxin B mycotoxicosis in the Swiss ICR mouse

The LD50 for rubratoxin B dissolved in dimethylsulphoxide and administered to ICR mice by ip injection was 0.31 (0.22-0.43) mg/kg body weight. Gross alterations consisted of congestion of the liver and spleen and pallor and mottling of the kidneys. The histopathological alterations seen were hepatic and splenic congestion and renal tubular degeneration. The morphopathogenesis of lesions following a single ip LD50 dose was evaluated in a second study. Hepatic lesions were observed in mice killed between 8 and 40 hr after dosing and included diffuse sinusoidal congestion with mild sinusoidal ectasia, leucostasis, multifocal cytoplasmic vacuolation and necrosis of individual hepatocytes. Renal lesions were mild, not time-dependent, and consisted of mild degenerative changes in tubular epithelial cells of the outer stripe of the outer zone of the medulla. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were increased 2 hr after dosing, peaked at 4 hr and returned to control values by the end of the test period. In a third study, rubratoxin B was administered ip daily for 1 wk at doses of 25, 50 and 75% of the ip LD50. Toxicity was dose related and cumulative with multiple doses at the highest dose. In a fourth study, rubratoxin B was administered ip at a dose of 75% of the ip LD50 daily for 1 wk. Histopathological alterations included hepatic congestion and mild sinusoidal ectasia, multifocal necrosis of hepatocytes, splenic congestion and mild renal tubular degeneration. Serum activities of AST and ALT were increased after multiple doses of rubratoxin B.

Effects of chlorphentermine and nitrogen dioxide on murine alveolar macrophages

Male Swiss-Webster mice were treated daily for 14 days with either 120 mg/kg chlorphentermine (CP) to produce pulmonary lipidosis or an equal volume of water. Animals in each treatment group were then exposed by whole-body inhalation to either air or NO2 for 48 h. Immediately following exposure, alveolar macrophages (MPs) were collected from each animal by bronchoalveolar lavage. Assays performed on adherent viable MPs showed some changes in metabolic reduction, phagocytosis, and killing activity. 5'-Nucleotidase activity and yeast phagocytosis and killing assays suggested that CP elicited an increase in phagocytosis over control levels. Although the percentage metabolic reduction and microbicidal killing activities following CP were not increased when compared to controls, absolute reduction and killing (percentage values times total MPs) were significantly increased. These increased functions seemed to be highly dependent on the large increase in the total number of MPs induced by CP. It is possible that the large accumulation of MPs in the airways of the lipidotic lung may help protect the alveolar epithelium from NO2 by quenching free radicals produced during NO2-induced lipid peroxidation.

Rubratoxin B mycotoxicosis in the Mongolian gerbil

The LD50 for rubratoxin B dissolved in dimethylsulphoxide and administered to Mongolian gerbils by ip injection was 2.0 (2.26-1.77) mg/kg body weight. The gross alterations observed at autopsy were pallor and mottling of the kidneys and liver and congestion of the spleen. The histopathological alterations seen were renal tubular degeneration and necrosis, degenerative changes in hepatocytes, and congestion of the spleen. The morphopathogenesis of lesions after a single ip LD50 dose was evaluated in a second study. The histopathological alterations that were observed were focal degeneration and necrosis of hepatocytes and renal tubular degeneration and necrosis. Hepatic lesions were observed in gerbils killed between 2 and 12 hr after dosing and included multifocal cytoplasmic vacuolation and coagulative necrosis of hepatocytes. The renal lesions were first observed 2 hr after dosing and increased to maximum severity at 40 hr after dosing. Tubular regeneration accompanied ongoing tubular necrosis at the end of the test period. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were increased 4 hr after dosing, peaked at 24 hr and remained elevated to the end of the test period. Serum K+ concentration was increased 16 hr after dosing and remained elevated to the end of the test period. In a third study, rubratoxin B was administered ip once daily for 7 days at doses of 25, 50 or 75% of the ip LD50. Toxicity was dose related and cumulative with multiple doses. Histopathological alterations included renal tubular degeneration and necrosis, mild tubular dilation and focal necrosis of hepatocytes. In a fourth study, rubratoxin B was administered ip at a dose of 25% of the ip LD50 once daily for 7 days. Histopathological alterations included renal tubular degeneration, mild renal tubular dilation and focal necrosis of hepatocytes. Activities of AST and ALT in serum were slightly increased after multiple doses of rubratoxin B. Results of urinalysis indicated hepatic and renal tubular damage.

Effects of acute pancreatitis on circulating lipids in dogs

Effects of acute pancreatitis on circulating lipids in dogs were evaluated by comparing the serum cholesterol and triglyceride concentrations and plasma lipoprotein electrophoretic patterns of 4 dogs with experimentally induced pancreatitis (EIP), 2 (healthy) sham-operated control (SOC) dogs, and 4 dogs with naturally acquired pancreatitis (NAP) with the concentrations and patterns of 23 healthy, nonoperated control (HNC) dogs. Blood samples were collected once from HNC dogs, 1 to 3 times during the course of the disease in dogs with NAP, and prior to and at 6, 12, 24, 48, 72, and 96 hours after induction of pancreatitis in dogs with EIP or after the sham operation in the SOC dogs. The dogs with EIP did not have turbid serum and did not develop hypercholesterolemia or hypertriglyceridemia. Three of the dogs with NAP had turbid serum and hypertriglyceridemia, and 3 had hypercholesterolemia. The electrophoretic tracings of HNC dogs had predominant alpha-1 peaks and small beta peaks; 2 of the HNC dogs also had small alpha-2 peaks. The tracings of dogs with EIP were similar to those of HNC dogs until 48 to 72 hours after induction of pancreatitis, when dogs with EIP developed increased beta lipoproteins, decreased alpha-1 lipoproteins, and movement of lipoproteins into the alpha-2 zone. The tracings of SOC dogs were similar to those of HNC dogs at all times. Compared with HNC dogs, dogs with NAP all had increased beta lipoproteins, and 2 had decreased alpha-2 lipoproteins. Two dogs with NAP had additional lipoprotein alterations, unlike any seen in dogs with EIP.

Rubratoxin B mycotoxicosis in the Syrian hamster

The LD50 for rubratoxin B dissolved in dimethylsulphoxide and administered to Syrian golden hamsters by ip injection was 0.4 (0.2-0.8) mg/kg body weight. The greatest number of deaths occurred 6-24 hr after administration. Gross alterations consisted of congestion of the liver, spleen and kidneys and histopathological alterations involved congestion of the spleen and congestion and mild degenerative changes in hepatocytes. In a second study, rubratoxin B was administered ip daily for 1 wk at doses of 25, 50 and 75% of the ip LD50. Mortality was greatest in the 50 and 75% dose groups. Toxicity was cumulative with multiple doses. Gross alterations were similar to those found in the LD50 study. Histopathological alterations included renal tubular degeneration and necrosis and focal necrosis of hepatocytes. The morphopathogenesis of lesions following a single ip LD50 dose was evaluated in a third study. Histopathological alterations were limited to the kidney and were characterized by renal tubular degeneration and necrosis. Renal lesions were first seen at 2 hr after administration and increased in severity to a maximum at 20 hr. Tubular regeneration was first seen at 24 hr and was found to the end of the test period (72 hr). Serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and serum concentrations of total and indirect bilirubin were increased by 8 hr after dosing and returned to control values by the end of the test period. In a fourth study, rubratoxin B was administered ip daily for 1 wk at a dose of 25% of the ip LD50. Gross alterations were similar to those in the other studies. Histopathological alterations included progressive renal tubular degeneration and necrosis. Serum activities of AST and ALT and concentration of blood urea nitrogen (BUN) were progressively increased with increasing numbers of doses. Urinalysis indicated progressive renal tubular damage.

The effect of chlorphentermine pretreatment on the toxicity of nitrogen dioxide in mice

Chlorphentermine HCl (CP) was used to induce preexisting alveolar alterations resembling a pulmonary lipidosis in mice to study these effects on the severity and duration of nitrogen dioxide (NO2) toxicity. Results indicated that a daily dose of 120 mg/kg for 14 days produced consistent histopathologic changes characterized by an accumulation of large foamy macrophages. Male Swiss-Webster mice were divided into a control and three treatment groups. Group 1 received 120 mg/kg CP po daily for 2 weeks followed by exposure to air for 48 hr. Group 2 received 20 ppm NO2 for 48 hr via whole-body inhalation, and group 3 received 120 mg/kg CP daily for 2 weeks followed by 20 ppm NO2 for 48 hr. The fourth group served as a nontreated control and received water in place of CP and air in place of NO2. All groups were compared by morphologic evaluation of pulmonary tissues at the light and electron microscopic levels at Days 0, 1, 3, 5, and 7 after the 48-hr exposure to air or NO2. In a second experiment using the same treatment groups, thin-section light microscopy was used to count the number of type I and type II cells and macrophages. NO2 exposure alone caused deaths in 20.8 and 18.5% of the mice in the two studies, but no deaths were seen in the combination groups from both experiments. Histopathologic evaluation showed a typical cellular response to the NO2 exposure, but differences were noted between the two groups receiving NO2 on this treatment. There was increased type II cell hyperplasia and terminal bronchiolitis on Days 0 and 1 but less on Days 3 to 7 in the combination group compared to the NO2 alone group. CP treatment prior to NO2 exposure caused less terminal bronchiolar epithelial hyperplasia and less pulmonary edema than was seen in the NO2 along group. The CP treatment appeared to protect against the lethal effects of NO2 at the concentration and time of exposure used and altered the cellular repair mechanism that occurs in response to NO2 toxicity. CP treatment prior to NO2 exposure caused significantly less loss of type I cells and less increase in type II cells due to NO2 damage. The combination treatment also caused an increase in macrophages greater than that seen in either individual treatment, and this number remained increased through 5 days post-NO2 exposure, whereas the NO2 alone caused a steady increase in macrophages following the exposure until Day 3.(ABSTRACT TRUNCATED AT 400 WORDS)

Single inhalation exposure to 90SrCl2 in the beagle dog: hematological effects

The toxicity of 90Sr administered by the inhalation route was studied in young adult Beagle dogs exposed once to aerosols containing 90SrCl2. Due to its relatively soluble chemical form, 90Sr was rapidly translocated from lung to bone where a substantial portion was retained for a long period of time. This resulted in only a brief radiation exposure of the respiratory tract and a protracted exposure of the skeleton. The long-term retained burdens ranged from 0.037 to 4.4 MBq 90Sr/kg body wt. Dogs were subsequently observed throughout their life span. Six dogs with long-term retained burdens of 1.7 to 4.1 MBq 90Sr/kg died at less than 32 days after exposure from radiation-induced bone marrow hypoplasia. Review of hematological parameters of all dogs showed a similar, consistent, and dose-related pancytopenia in those animals having a long-term retained burden of greater than 0.37 MBq 90Sr/kg. Thrombocytopenia and neutropenia persisted in all exposed dogs through 1000 days after exposure. For reference purposes, a burden of 0.37 MBq 90Sr/kg is calculated to deliver an average radiation dose to the skeleton over 30, 100, and 1000 days after intake of 1.0, 2.8, and 17 Gy, respectively. The hematologic changes were similar to those seen in people exposed to high doses of whole-body external radiation.

Listeriosis in an immature black buck antelope (Antilope cervicapra)

A 10-week-old, black buck antelope calf, from the Mesker Park Zoo in Evansville, Indiana was found dead without observed signs of illness. Necropsy disclosed disseminated ecchymoses on the pericardium, diaphragm, intestines, and renal capsules and more extensive hemorrhage in the muscles of the hindquarters. There were numerous, 1 mm, pale foci on the capsular and cut surfaces of the liver and spleen which, on microscopic examination, were necrotic foci containing variable numbers of neutrophils and mononuclear leukocytes with numerous, short, Gram-positive, cocco-bacilli at the periphery. Listeria monocytogenes was isolated from the liver. Septicemia is the most common form of listeriosis in non-domestic ruminants. Listeriosis should be suspected when unexpected deaths are accompanied by multifocal necrotizing hepatitis and splenitis, myocarditis, and disseminated hemorrhage.

Changes in collagen metabolism and proteinolysis after repeated inhalation exposure to ozone

To study the changes in collagen metabolism that occur in the pathogenesis of pulmonary fibrosis, female rats were exposed to 0, 0.57, and 1.1 ppm ozone for 19 hr/day for 11 days and sacrificed 12 or 60 days after initiation of exposure. The lungs of rats sacrificed at 12 days after initiation of exposure to 1.1 ppm had interstitial pneumonia characterized by a mixed inflammatory cell infiltrate, type II cell hyperplasia, and fibroplasia, a proliferation of the collagen-producing cells; increased cathepsin D and macrophage elastase activity, indicating macrophage-induced proteinolysis; a reduced percentage of the increased collagen production that was ultrafilterable, indicating a decreased rate of intracellular degradation of newly produced collagen prior to its secretion; and increased lavage fluid hydroxyproline, indicating turnover of extracellular collagenous matrix. Reduced intracellular collagen degradation correlated directly with both increased net collagen production and fibroplasia in rats exposed to 1.1 ppm ozone for 11 days. These changes preceded an increased total lung collagen and the development of modest fibroplasia and fibrosis in the alveolar duct regions by 60 days after the 1.1 ppm ozone exposure was initiated.

Comparative study of bronchoalveolar lavage fluid: effect of species, age, and method of lavage

The analysis of bronchoalveolar lavage fluid has been used as a probe to detect lung injury in toxicological studies and to diagnose the disease state of the lung in humans. To determine how variable the content of lavage fluid from different species is, bronchoalveolar lavage fluids from normal individuals of four species (hamster, rat, guinea pig, and rabbit) were compared for enzymatic and cellular content as well as total protein and sialic acid. In addition, lavage fluid from young adult rats and hamsters was compared to that from older animals. Finally, the effect of the method of lavage on lavage fluid content was evaluated by comparing lavage fluid obtained from an excised lung with that from a lavage performed in vivo. In general, lavage fluids from the four species were similar. However, lavage fluid from guinea pigs had higher numbers of granulocytes and higher mean beta-glucuronidase activities than fluids from other species. Rats had higher mean alkaline phosphatase activities, reflecting higher serum values of this enzyme. Older hamsters had more protein in their lavage fluid than younger animals, and older rats had lower elastase inhibitory activity than young rats. Performing lavage in vivo, as compared to in vitro, did not greatly alter the lavage fluid except for a trend toward a higher level of sialic acid in fluid taken from the living animal.

Comparative acute toxicity of four nickel compounds to F344 rat lung

Nickel subsulfide (Ni3S2), nickel chloride (NiCl2), nickel sulfate (NiSO4), and nickel oxide (NiO) are compounds of widely differing solubility encountered in the nickel-refining and electroplating industries. Inhalation is a common route of exposure and toxicity to the respiratory tract is possible. The purpose of this study was to evaluate the biochemical, cytological, and morphological changes in lung following administration of these compounds by intratracheal instillation. F344/Crl rats were administered a single dose of nickel compound containing 0.0, 0.01, 0.10, or 1.0 mumol Ni by intratracheal instillation. Rats were sacrificed at 1 or 7 days after compound administration, with half the animals in each exposure group taken for determination of nickel lung burden and the remaining half used for evaluation of biochemical, cytological, and histological changes. In the latter group, the right lung was lavaged and the fluid obtained was analyzed for indicators of pulmonary inflammation: lactate dehydrogenase (LDH), beta-glucuronidase (BG), total protein (TP), glutathione reductase (GR), glutathione peroxidase (GP), and sialic acid (SA). Total and differential cell counts on cells recovered in lavage fluid were also determined. The left lobe was examined for morphological changes. Clearance of nickel from the lung was most rapid for NiCl2 and NiSO4, followed by Ni3S2 and NiO. Minimal changes in all parameters were observed at 1 day after exposure. No significant changes in any parameter occurred in rats exposed to NiO, while Ni3S2, NiSO4, and NiCl2 caused increased in LDH, BG, TP, GR, SA, and total nucleated cells at 7 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute inhalation toxicopathology of lithium combustion aerosols in rats

Male and female F344/Lov rats were exposed to aerosols produced by burning lithium metal under conditions designed to stimulate a fire in the containment building of a fusion reactor. Lithium combustion aerosols were generated by sweeping lithium vapor into air atmospheres with controlled CO2 and H2O concentrations. Chemical analyses of the aerosols produced indicated a dependence of the chemical form of carbon dioxide concentrations and relative humidity. Under conditions of low CO2 concentration and low relative humidity (less than 25%), the aerosol was predominantly lithium monoxide with some lithium hydroxide and about 12% lithium carbonate. Under conditions of high relative humidity (greater than 75%), the aerosol was primarily lithium hydroxide with about 23% lithium carbonate. Although these two aerosols might be expected to have different acute toxicities based on their differing alkalinities, the 14-day LC50 values (with 95% confidence limits) determined after 4-hr exposures were 940 (730-1200) mg/m3 for the lithium oxide and hydroxide mixture and 960 (830-1200) mg/m3 for the lithium hydroxide aerosols. Histopathologic lesions were observed in the nasal turbinates, larynx, and occasionally in the lungs with both aerosols. The most prominent lesions were necrotizing laryngitis and ulcerative rhinitis. Pulmonary lesions represented a secondary extension of the upper respiratory tract lesions rather than a primary manifestation of lithium toxicity. The similarities in the LC50 values and also in the histopathologic lesions observed suggest that any Li2O in the aerosol reacted rapidly with water vapor in the respiratory tract to form LiOH prior to deposition.

Evaluation of a spectrophotometric method for canine serum lipase determination

The British antilewisite butyrate-dithionitrobenzoate (BALB-DTNB) spectrophotometric serum lipase assay was evaluated for precision, accuracy, and diagnostic usefulness in analyzing canine sera. Sera samples from clinically healthy dogs, dogs with experimentally induced pancreatitis, and dogs with spontaneous pancreatitis were analyzed. A titrimetric method of serum lipase determination was used for comparison. Although the BALB-DTNB method was not found to be precise or accurate for determining the lipase activity of canine serum samples, it seemed to be at least as diagnostically useful as the titrimetric procedure. The small sample size requirement and the speed of analysis of the BALB-DTNB procedure are advantages of this method over the titrimetric method, and thus, its use in place of the titrimetric method is justified. A laboratory reference range of 3 to 37 IU/L was determined for canine serum.

Inhalation toxicity of lithium combustion aerosols in rats

Studies of the acute inhalation toxicity of lithium combustion aerosols were undertaken to aid in evaluating the health hazards associated with the proposed use of lithium metal in fusion reactors. A system was developed to generate lithium combustion aerosols by sweeping vapor from molten lithium metal into a controlled air atmosphere. Male and female F344/Lov rats, 9-12 wk of age, were exposed once for 4 h to concentrations of 2600, 2300, 1400, or 620 mg/m3 of aerosol (MMAD = 0.69 micrometer, sigma g = 1.45) that was approximately 80% lithium carbonate and 20% lithium hydroxide to determine the acute toxic effects. Fourteen-day LC50 values (with 95% confidence limits) of 1700 (1300-2000) mg/m3 for the male rats and 2000 (1700-2400) mg/m3 for the female rate were calculated. Clinical signs of anorexia, dehydration, respiratory difficulty, and perioral and perinasal encrustation were observed. Body weights were decreased the first day after exposure in relation to the exposure concentration. In animals observed for an additional 2 wk, body weights, organ weights, and clinical signs began to return to preexposure values. Histopathologic examination of the respiratory tracts from the animals revealed ulcerative or necrotic laryngitis, focal to segmental ulcerative rhinitis often accompanied by areas of squamous metaplasia, and, in some cases, a suppurative bronchopneumonia or aspiration pneumonia, probably secondary to the laryngeal lesions. The results of these studies indicate the moderate acute toxicity of lithium carbonate aerosols and will aid in the risk analysis of accidental releases of lithium combustion aerosols.

Effect of pretreatment with selenium-vitamin E on monensin toxicosis in cattle

Ten female beef calves weighing approximately 180 kg each were allotted to 2 groups of 5 each before they were given (orally) monensin (50 mg/kg of body weight). In group A, the calves were given (IM) a commercial selenium-vitamin E (Se-E) preparation (0.25 mg of Se and 17 IU of alpha-tocopherol/kg of body weight) at 72 and 24 hours before monensin was given. The calves in group B were injected at the 2 times with isotonic saline solution. Clinical signs of monensin toxicosis, including lethargy and recumbency, appeared on day 2 in the calves given the Se-E pretreatment, compared with the onset on day 1 in the saline solution-pretreated calves. All calves in the 2 groups died, but mean survival time was longer in group A (4.4 vs 2.2 days). Lesions of monensin toxicosis were myocardial necrosis, skeletal myonecrosis, pulmonary congestion, and rumenitis. The frequency and severity of the lesions were similar for both groups of calves. The results of the present study indicate that Se-E pretreatment modifies the development of monensin toxicosis in cattle.

Lesions of porcine necrotic ear syndrome

Porcine necrotic ear syndrome is a disease of swine characterized by large erosive lesions at the margin of the pinna(e). The gross and microscopic characteristics of the lesions were studied in 38 pigs selected from eight affected swine herds. The progression of the lesions was examined in a herd of 174 weaned pigs in a total confinement nursery. The lesions began as a superficial vesicular dermatitis associated with superficial auricular trauma and progressed to become exudative and encrusted. Localized lesions slowly healed or sporadically progressed to deep necrotic ulcers. The early lesions resembled the epidermal changes produced by Staphylococcus hyicus. Deep ulceration and necrosis was attributed to the invasion of streptococci into the dermis resulting in cellulitis, vasculitis, thrombosis, ischemia, and necrosis.

Clinical, clinicopathologic, and pathologic alterations in acute monensin toxicosis in cattle

Twenty beef calves weighing approximately 180 kg were allotted to 3 groups. In group A, 6 calves were given 25 mg of mycelial monensin/kg of body weight orally and were evaluated at 1, 2, and 4 days for clinical, ECG, clinicopathologic, and pathologic alterations. In group B, 7 calves were given a single dose of monensin (40 mg/kg) and 5 were given a 2nd 40 mg/kg dose on day 7; calves were evaluated at days 1, 2, 4, 7, 8, 9, and 11. In group C, 2 calves served as controls. Monensin-treated calves developed anorexia, diarrhea, and lethargy after day 1. One group B calf died on day 7 with lesions of congestive heart failure. Electrocardiographic abnormalities were not observed in group A calves; in group B, prolongation of Q-T and QRS intervals occurred from days 2 to 11 and first degree heart block was seen from days 7 to 11. Clinicopathologic alterations included: increased serum activities of aspartate aminotransferase and creatine kinase in group B calves after day 2; decreased serum K+, Na+, and Ca2+ concentrations in both groups, and postdosing occurrence of leukocytosis. Calves were euthanatized sequentially and the lesions of monensin toxicosis were present in the heart, skeletal muscles, and rumen in groups A and B. Disseminated pale yellowish-brown areas of necrosis were present in the ventricular myocardium of 6 of 12 group B calves. Gross lesions were not present in the skeletal muscles or rumen. Microscopically, the myocardial and skeletal muscular lesions were characterized by sarcoplasmic vacuolation from mitochondrial swelling and lipid accumulation in calves killed after day 1 in groups A and B, and by myocardial necrosis with contraction bands, but without calcification, in group B calves killed by day 4. Acute rumenitis was present in groups A and B calves. Myotoxic effects of monensin may be related to its action as an ionophore producing altered intracellular ion concentrations and initiating degeneration and necrosis in striated muscle fibers.

In vitro and in vivo response after exposure to man-made mineral and asbestos insulation fibers

The relative in vitro and in vivo toxicity of several types of manufactured fibrous glass insulation and crocidolite asbestos was investigated to aid in selection of a suitable glass fiber for subsequent use in inhalation exposures. The in vitro cytotoxicity to pulmonary alveolar macrophages of small glass fibers from microfiber insulation (count median diameter (CMD) approximately 0.1-0.2 micrometer) was greater than that of the larger fibers from household insulation (CMD approximately 2.4 micrometers). To screen for in vivo pulmonary toxicity, 2-21 mg of glass or asbestos fibers were administered in divided doses to male Syrian hamsters by intratracheal instillation. Animals were sacrificed at 1, 3.5 and 11 months following initial administration of material. One type of glass microfiber [count median diameter (CMD) approximately 0.1 micrometer] caused deaths from pulmonary edema at early times after instillation. High levels of asbestos, a second glass microfiber (CMD approximately 0.2 micrometer) and one type of household insulation fiber (CMD 2.3 micrometers) all resulted in increase in total collagen and mild pulmonary fibrosis at later times after instillation, although microfiber insulation produced a greater response than household insulation. Asbestos insulation produced the greatest response. A five-day inhalation exposure to a high level of glass microfibers deposited in lung less than 10 percent of the lowest instilled amount which elicited indications of lung injury. This amount did not produce significant biological changes at 1 to 12 months after exposure.

Effects of the single or repeated inhalation exposure of Syrian hamsters to aerosols of 239PuO2

Male Syrian hamsters were scheduled to be exposed by inhalation approximately every 60 days for 1 year (7 exposures) to aerosols of 239PuO2 beginning at 84 days of age. Other hamsters were exposed once when 84 or 320 days of age. Plutonium-239 deposited in the lungs by the repeated inhalation exposures was cleared from the lungs at a rate similar to that following a single inhalation exposure. The incidence of radiation pneumonitis, bronchiolar epithelial hyperplasia, and alveolar squamous metaplasia were the only lesions that were related to radiation dose. Only two primary lung tumours were found among the hamsters exposed to 239PuO2. No primary lung tumours were found in the control hamsters. It was concluded that the incidence of lung tumours was not increased by the protraction of the alpha radiation dose to the lungs from repeated inhalation exposure.