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Routine monitoring of clinicopathologic data is a critical component in the management of older patients because blood and urine testing allows the veterinarian to monitor trends in laboratory parameters, which may be the early indicators of disease. Laboratory profiling often provides an objective and sensitive indicator of developing disease before obvious clinical signs or physical examination abnormalities are observed. The primary key to the power of this evaluation is that the data are collected year after year during wellness checks and are examined serially. Chronic renal failure, chronic active hepatitis, canine hyperadrenocorticism, diabetes mellitus, and feline hyperthyroidism were reviewed and expected laboratory findings are summarized.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Hematologic and/or serum chemical analyses were done on a total of 27 non-tranquilized adult and juvenile wild sea otters, 66 tranquilized adult and juvenile wild sea otters, and 26 wild sea otter pups. The median and inner 90 percentile range were determined for the adult, juvenile, and pup groups and for the following subgroups: adult male versus adult female, juvenile male versus juvenile female, pup male versus pup female, captured with dip net versus captured with Wilson trap, and tranquilized adults and juveniles versus non-tranquilized adults and juveniles. When values for adults were compared to values for juveniles and pups, hematocrits, red blood cell counts, and hemoglobin levels were significantly lower in pups. This is consistent with documented findings in other species. White cell counts were also somewhat lower in younger animals. Among the subgroups, significantly higher hemoglobin levels, white cell counts and neutrophil counts were found in adult females than in adult males. This is in direct contrast to what is seen in other mammalian species and warrants further documentation. Method of capture and tranquilization did not appear to influence either hematologic or serum biochemical determinations from a clinical perspective.

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)

We investigated the modifying effects of preexisting, bleomycin-induced pulmonary fibrosis on the deposition, retention, and biological effects of inhaled 239PuO2 in the rat. Among rats exposed to similar airborne concentrations of 239PuO2, initial lung burdens of 239Pu per kilogram body mass were similar whether or not pulmonary fibrosis was present. However, clearance of 239Pu from the lungs was significantly decreased in the rats with preexisting pulmonary fibrosis. The incidence of lung lesions (epithelial hyperplasia, diffuse macrophage increases and aggregation, and loose and dense connective tissue) was significantly greater among rats with preexisting pulmonary fibrosis than among the exposed controls. Rats with preexisting fibrosis had shorter life spans than 239PuO2-exposed control rats. When groups of rats with similar alpha doses to the lungs were compared, the incidences of neoplastic lesions in the lung, the times to death of rats with lung neoplasms, and the risk of lung tumors per unit of alpha dose to the lungs in rats with or without pulmonary fibrosis were similar. The results of this study suggest that humans with uncomplicated pulmonary fibrosis may not be more sensitive to the carcinogenic effects of inhaled 239PuO2 than are individuals with normal lungs, assuming that the total alpha doses to the lungs are similar.

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.

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.

Administration of selenium-vitamin E (Se-E) to weanling rabbits chronically treated with adriamycin (ADR) resulted in decreased incidence and severity of cardiomyopathy and decreased cumulative mortality during a 10-week experiment. However, Se-E did not protect against extracardiac lesions or against a number of clinicopathologic alterations induced by chronic ADR toxicosis. Histopathologic alterations of ADR-induced cardiomyopathy were concentrated periarterially in the free and septal walls of the left ventricle. Initial vacuolar degeneration of injured cardiac muscle cells was followed by myofibrillar lysis and eventual cell death with subsequent interstitial fibrosis. Ultrastructurally, degenerated cardiac muscle cells had 3 prominent alterations: (1) sarcoplasmic vacuolization caused by distention of elements of sarcoplasmic reticulum and T-tubules, (2) degeneration of mitochondria forming large myelin figures from disrupted membranes, and (3) lysis of myofibrils producing granular sarcoplasmic masses. Severely injured fibers were necrotic and macrophages invaded to remove cellular debris. The interstitium was distended by edema and increased amounts of collagen. Extracardiac lesions in rabbits with chronic ADR toxicosis included the usually recognized alterations involving cell-renewal systems in kidney, testis, bone marrow, skin, and alimentary tract, as well as vacuolar degeneration of skeletal muscle and focal loss of pancreatic tissue, with ensuing pancreatic fibrosis and fat necrosis. Deaths in ADR-treated rabbits usually were precipitated by terminal septic embolism. The partial protection afforded by Se-E against ADR-induced cardiomyopathy may be associated with stabilization of the membranes of injured muscle cells or with prevention of ADR-induced inhibition of coenzyme Q10-dependent mitochondrial enzymes.

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)

Radioisotopic bone scans and radiography were used to detect bone neoplasms in 144 dogs that inhaled alpha-particle-emitting 238PuO2 particles. Radiography was used routinely to survey the skeleton of the dogs. Nineteen dogs developed bone neoplasms; 17 of these were studied with bone scans and radiography; both methods showed a high degree of success in detecting bone neoplasms. Predominant regions of occurrence have been the lumbar region of the spine and the humerus. The bone scanning method used gamma-camera detection of IV injected 99mTc-labeled methylene diphosphonate. All neoplasms detected radiographically also were identified by bone scans. In addition, 3 lesions confirmed histologically as osteosarcomas were detected by bone scanning, but were missed by radiography. Bone scanning was a more sensitive means for the detection of bone neoplasms than were routine radiographic procedures.

An outbreak of acute canine parvoviral enteritis occurred over 2 months in a closed beagle dog research colony containing approximately 1840 dogs. Of the 183 puppies housed in the whelping kennel, the morbidity and mortality were 36% and 12%, respectively. Four cases occurred in the adult population with three deaths. The disease was characterized clinically by anorexia, diarrhea, rapid dehydration, and panleukopenia. It was more prevalent in weaned puppies than in nursing puppies or adult dogs.

A retrospective study of red blood cell parameters in 53 dogs with experimental radiation-induced hemangiosarcoma showed 24 had anemia. Morphologic alterations in red blood cells in peripheral blood films from anemic dogs included signs of regeneration (anisocytosis and polychromasia), hypochromasia, red cell fragmentation and acanthocytosis. The degree and type of red cell changes varied from dog to dog and generally correlated with the principal site of tumor involvement. Blood from dogs with tumors principally involving liver had red cell regeneration, fragmentation and acanthocytosis. Blood from dogs with tumors primarily involving the heart had only red cell fragmentation. Blood films from dogs with skeletal and pulmonary hemangiosarcomas were similar to blood films from dogs with hepatic hemangiosarcoma except that red cell alterations generally were less severe. Scanning and transmission electron micrographic evaluation of neoplastic tissue showed large amounts of fibrin within neoplastic vascular sinuses and disruption and distortion of red blood cells traversing these abnormal vascular beds. The red blood cell fragmentation syndrome associated with radiation-induced hemangiosarcomas therefore was considered to be a microangiopathic hemolytic anemia of localized origin.

Red blood cell fragments in blood smears from dogs are described morphologically and pathogenetically. Categories include microangiopathic fragmentation, spherocytic fragmentation. Heinz body fragmentation, metabolic fragmentation associated with systemic disease, and artifactual fragmentation. Microangiopathic fragmentation is associated with direct physical damage to normal circulating red blood cells as they pass through abnormal capillary beds. Spherocytic fragmentation is a common feature of immune-mediated hemolytic anemia and results from the removal of portions of antibody-coated erythrocyte plasma membranes by phagocytes of the reticuloendothelial system. Heinz body fragmentation occurs when rigid particles of oxidized hemoglobin are torn from affected red cells as they circulate through the spleen. Metabolic fragmentation is an ill-defined syndrome most commonly associated with cholesterol loading of red cell membranes caused by lipid metabolism abnormalities. Resulting spiculated red cells are more susceptible to traumatic disruption. All the types of red cell fragmentation described in dogs have been observed and documented in man.

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.

In canine veterinary medicine, both acute and chronic renal failure occur relatively frequently, from a variety of causes similar to those in man. However, the normal dog has a very high protein catabolic rate and high endogenous kidney function, and, therefore, requires frequent and highly efficient dialysis, for maintenance during renal failure. We have developed techniques to support the uremic dog with hemodialysis. An experimentally anephric dog, and two dogs with clinically occurring acute renal failure (caused by ethylene glycol intoxication and heat stroke) have been supported with frequent use of hollow fiber dialyzers, using a carotid artery to jugular vein shunt. Patency of shunts was maintained by administration of oral aspirin. A very high urea and creatinine generation rate necessitated daily dialysis during much of the clinical course of renal failure. The experimentally anuric animal was supported for 35 days. The ethylene glycol-induced renal failure animal was euthanized on the 21st day, and the heat stress-induced renal failure animal recovered sufficient intrinsic renal function after 16 days of dialysis for maintenance of life without dialysis.

Cytologic examination of serial peritoneal fluid samples of nine experimental ponies was performed during a 72 hour period following laparotomy. Six of the ponies had jejunal infarction induced by occlusion of the corresponding vasculature. Cytologic examination was also performed on the peritoneal fluid of a series of horses with naturally occurring abdominal crises presented to the Large Animal Clinic. A rapid staining technique allowed evaluation of smears within 5 minutes of obtaining the fluid. Alterations in peritoneal fluid of the experimental and clinical cases reflected an acute inflammatory response. In the experimental ponies, the degree of degenerate changes in the neutrophils varied considerably between the ponies with induced jejunal infarction and the controls. Extracellular bacteria and a severe degenerative inflammatory response in the peritoneal fluid of the experimental ponies and horses with naturally occurring abdominal crises provided a grave prognosis for survival. The ease of performing cytologic examination of peritoneal fluid and the potential value of the findings supports routine diagnostic use.

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.

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.

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.

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.

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.

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.

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.

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.

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.