Tissue-Resident Alveolar Macrophages Reduce Ozone-induced Inflammation via MerTK Mediated Efferocytosis

Lung inflammation, caused by acute exposure to ozone (O3) - one of the six criteria air pollutants - is a significant source of morbidity in susceptible individuals. Alveolar macrophages (AMØs) are the most abundant immune cells in the normal lung and their number increases following O3 exposure. However, the role of AMØs in promoting or limiting O3-induced lung inflammation has not been clearly defined. Here, we used a mouse model of acute O3 exposure, lineage tracing, genetic knockouts, and data from O3-exposed human volunteers to define the role and ontogeny of AMØs during acute O3 exposure. Lineage tracing experiments showed that 12, 24, and 72 h after exposure to O3 (2 ppm) for 3h all AMØs were tissue-resident origin. Similarly, in humans exposed to FA and O3 (200 ppb) for 135 minutes, we did not observe ~21h post-exposure an increase in monocyte-derived AMØs by flow cytometry. Highlighting a role for tissue-resident AMØs, we demonstrate that depletion of tissue-resident AMØs with clodronate-loaded liposomes led to persistence of neutrophils in the alveolar space after O3 exposure, suggesting that impaired neutrophil clearance (i.e., efferocytosis) leads to prolonged lung inflammation. Moreover, depletion of tissue-resident AMØ demonstrated reduced clearance of intratracheally instilled apoptotic Jurkat cells, consistent with reduced efferocytosis. Genetic ablation of MerTK - a key receptor involved in efferocytosis - also resulted in impaired clearance of apoptotic neutrophils followed O3 exposure. Overall, these findings underscore the pivotal role of tissue-resident AMØs in resolving O3-induced inflammation via MerTK-mediated efferocytosis.

Eos Promotes TH2 Differentiation by Interacting with and Propagating the Activity of STAT5

The Ikaros zinc-finger transcription factor Eos has largely been associated with sustaining the immunosuppressive functions of regulatory T cells. Paradoxically, Eos has more recently been implicated in promoting proinflammatory responses in the dysregulated setting of autoimmunity. However, the precise role of Eos in regulating the differentiation and function of effector CD4+ T cell subsets remains unclear. In this study, we find that Eos is a positive regulator of the differentiation of murine CD4+ TH2 cells, an effector population that has been implicated in both immunity against helminthic parasites and the induction of allergic asthma. Using murine in vitro TH2 polarization and an in vivo house dust mite asthma model, we find that EosKO T cells exhibit reduced expression of key TH2 transcription factors, effector cytokines, and cytokine receptors. Mechanistically, we find that the IL-2/STAT5 axis and its downstream TH2 gene targets are one of the most significantly downregulated pathways in Eos-deficient cells. Consistent with these observations, we find that Eos forms, to our knowledge, a novel complex with and supports the tyrosine phosphorylation of STAT5. Collectively, these data define a regulatory mechanism whereby Eos propagates STAT5 activity to facilitate TH2 cell differentiation.

Scavenger receptor BI attenuates oxidized phospholipid-induced pulmonary inflammation

Damage associated molecular patterns (DAMPs) are molecules released from dead/dying cells following toxicant and/or environmental exposures that activate the immune response through binding of pattern recognition receptors (PRRs). Excessive production of DAMPs or failed clearance leads to chronic inflammation and delayed inflammation resolution. One category of DAMPs are oxidized phospholipids (oxPLs) produced upon exposure to high levels of oxidative stress, such as following ozone (O3) induced inflammation. OxPLs are bound by multiple classes of PRRs that include scavenger receptors (SRs) such as SR class B-1 (SR-BI) and toll-like receptors (TLRs). Interactions between oxPLs and PRRs appear to regulate inflammation; however, the role of SR-BI in oxPL-induced lung inflammation has not been defined. Therefore, we hypothesize that SR-BI is critical in protecting the lung from oxPL-induced pulmonary inflammation/injury. To test this hypothesis, C57BL/6J (WT) female mice were dosed with oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (oxPAPC) by oropharyngeal aspiration which increased pulmonary SR-BI expression. Following oxPAPC exposure, SR-BI deficient (SR-BI-/-) mice exhibited increased lung pathology and inflammatory cytokine/chemokine production. Lipidomic analysis revealed that SR-BI-/- mice had an altered pulmonary lipidome prior to and following oxPAPC exposure, which correlated with increased oxidized phosphatidylcholines (PCs). Finally, we characterized TLR4-mediated activation of NF-κB following oxPAPC exposure and discovered that SR-BI-/- mice had increased TLR4 mRNA expression in lung tissue and macrophages, increased nuclear p65, and decreased cytoplasmic IκBα. Overall, we conclude that SR-BI is required for limiting oxPAPC-induced lung pathology by maintaining lipid homeostasis, reducing oxidized PCs, and attenuating TLR4-NF-κB activation, thereby preventing excessive and persistent inflammation.

Ultrasonography and digital radiography findings in sheep with clinical disease associated with small ruminant lentivirus infection

Digital radiography and ultrasonographic images were used in this case series to evaluate 4 ewes from a single flock for chronic weight loss and ill-thrift. On examination, all displayed tachypnea, dyspnea, coughing, and normothermia with abnormal thoracic auscultations. Three of the 4 animals were diagnosed with chronic respiratory disease associated with Maedi-visna (MV) infection confirmed via serologic testing. Diagnostic thoracic imaging identified characteristics consistent with pathological lesions associated with interstitial pneumonia in the 3 MV affected animals; these findings were absent in the animal that tested negative for MV. Key clinical message: Diagnostic imaging may be useful to clinicians looking to obtain further visualization of lung pathologies and as a reliable means of detecting thoracic lesions indicative of interstitial pneumonia on-farm. These results can be used to aid the practitioner in determining appropriate further diagnostic testing and treatment strategies while awaiting confirmatory test results for diagnosis of MV.

The pathology of natural and experimentally induced Campylobacter jejuni abortion in sheep

We describe here the gross and microscopic lesions in 18 experimentally induced and 120 natural Campylobacter abortions. In natural Campylobacter abortions, gross lesions were reported infrequently; placentitis was recorded in 6% and hepatic lesions in 4% of our field cases. Placentitis was the microscopic lesion identified most consistently in natural abortions (93%) and was often observed in association with abundant bacterial colonies in chorionic villi (54%) and less often with placental vasculitis (13%). In natural abortions, suppurative fetal pneumonia (48%), necrosuppurative hepatitis (16%), and purulent meningitis (7%) were also observed. The better-preserved specimens from experimentally induced abortions were utilized to define placental changes more precisely. Placentitis was identified in all 18 experimentally induced abortions and was observed most consistently in the chorionic villus stroma (100%), often accompanied by suppurative surface exudate (89%). An inflammatory infiltrate was less commonly identified in the cotyledonary hilus (39%) and intercotyledonary placenta (22%). Bacteria were visualized in H&E-stained sections in 89% of placentas from experimentally infected ewes, primarily as well-demarcated bacterial colonies within subtrophoblastic, sinusoidal capillaries (89%), in the cotyledonary villus stroma (89%), and within the cytoplasm of trophoblasts (22%). Transmission electron microscopy and immunohistochemistry confirmed that the vast majority of the well-demarcated bacterial colonies characteristic of Campylobacter abortion were within subtrophoblastic sinusoidal capillaries. The most characteristic microscopic lesions identified in cases of Campylobacter abortion in sheep were placentitis with placental bacterial colonies, placental vasculitis, and fetal pneumonia.

Sex Differences in Pulmonary Eicosanoids and Specialized Pro-Resolving Mediators in Response to Ozone Exposure

Ozone (O3) is a criteria air pollutant known to increase the morbidity and mortality of cardiopulmonary diseases. This occurs through a pulmonary inflammatory response characterized by increased recruitment of immune cells into the airspace, pro-inflammatory cytokines, and pro-inflammatory lipid mediators. Recent evidence has demonstrated sex-dependent differences in the O3-induced pulmonary inflammatory response. However, it is unknown if this dimorphic response is evident in pulmonary lipid mediator metabolism. We hypothesized that there are sex-dependent differences in lipid mediator production following acute O3 exposure. Male and female C57BL/6J mice were exposed to 1 part per million O3 for 3 hours and were necropsied at 6 or 24 hours following exposure. Lung lavage was collected for cell differential and total protein analysis, and lung tissue was collected for mRNA analysis, metabololipidomics, and immunohistochemistry. Compared to males, O3-exposed female mice had increases in airspace neutrophilia, neutrophil chemokine mRNA, pro-inflammatory eicosanoids such as prostaglandin E2, and specialized pro-resolving mediators (SPMs) such as resolvin D5 in lung tissue. Likewise, precursor fatty acids (arachidonic and docosahexaenoic acid; DHA) were increased in female lung tissue following O3 exposure compared to males. Experiments with ovariectomized females revealed that loss of ovarian hormones exacerbates pulmonary inflammation and injury. However, eicosanoid and SPM production were not altered by ovariectomy despite depleted pulmonary DHA concentrations. Taken together, these data indicate that O3 drives an increased pulmonary inflammatory and bioactive lipid mediator response in females. Furthermore, ovariectomy increases susceptibility to O3-induced pulmonary inflammation and injury, as well as decreases pulmonary DHA concentrations.

A Homologous Bacterin Protects Sheep against Abortion Induced by a Hypervirulent Campylobacter jejuni Clone

Campylobacter jejuni clone SA has emerged as the predominant cause of ovine abortion outbreaks in the United States (US). Despite the fact that commercial Campylobacter vaccines are available, their efficacy in protecting abortion induced by C. jejuni clone SA is uncertain, and a protective vaccine is needed to control the disease. In this study, an experimental homologous bacterin (made of a clone SA isolate) and two commercial Campylobacter vaccines were evaluated for their protection against C. jejuni clone SA-induced sheep abortion. All vaccines induced high levels of antibodies against C. jejuni clone SA in pregnant ewes, but only the experimental homologous bacterin produced significant protection (80%). Immunoblotting showed that the experimental vaccine elicited more specific antibodies against C. jejuni clone SA. These findings strongly suggest the necessity of developing a homologous vaccine for the control C. jejuni clone SA induced abortion on sheep farms.

Experimental evaluation of tulathromycin as a treatment for Campylobacter jejuni abortion in pregnant ewes

OBJECTIVE

To evaluate the efficacy of tulathromycin for prevention of abortion in pregnant ewes when administered within 24 hours after experimental inoculation with Campylobacter jejuni.

ANIMALS

20 pregnant ewes between 72 and 92 days of gestation.

PROCEDURES

All ewes were inoculated with a field strain of C jejuni (8.5 × 10⁸ to 10.6 × 10⁸ CFUs, IV). Eighteen hours later, ewes received either tulathromycin (1.1 mL/45 kg [2.4 mg/kg], SC; n = 10) or sterile saline (0.9% NaCl) solution (1.1 mL/45 kg, SC; sham; 10). Ewes were euthanized immediately after observation of vaginal bleeding, abortion, or completion of a 21-day observation period. Necropsy was performed on all ewes, and tissue specimens were obtained for bacterial culture and histologic examination.

RESULTS

1 sham-treated ewe and 1 tulathromycin-treated ewe developed signs of severe endotoxemia and were euthanized within 24 hours after C jejuni inoculation. Seven sham-treated and 2 tulathromycin-treated ewes developed vaginal bleeding or aborted and were euthanized between 4 and 21 days after C jejuni inoculation. The proportion of tulathromycin-treated ewes that developed vaginal bleeding or aborted during the 21 days after C jejuni inoculation (2/9) was significantly less than that for the sham-treated ewes (7/9).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that administration of tulathromycin to pregnant ewes following exposure to C jejuni was effective in decreasing the number of C jejuni-induced abortions. Because of concerns regarding the development of macrolide resistance among Campylobacter strains, prophylactic use of tulathromycin in sheep is not recommended.

Euthanasia- and Lavage-mediated Effects on Bronchoalveolar Measures of Lung Injury and Inflammation

Accurate and reproducible assessments of experimental lung injury and inflammation are critical for basic and translational research. In particular, investigators use various methods for BAL and euthanasia; however, the impact of these methods on assessments of injury and inflammation is unknown. To define potential effects, we compared methods of lavage and euthanasia in uninjured mice and after a mild lung injury model (ozone). C57BL/6J male mice (8-10 weeks old) underwent BAL after euthanasia with ketamine/xylazine, carbon dioxide (CO₂), or isoflurane. BAL methods included 800 μl of isotonic solution instilled and withdrawn three times, and one or three passive fills and drainage to 20 cm H₂O. Parallel experiments were performed 24 hours after 3 hours of ozone (O₃) exposure at 2 ppm. BAL total cell counts/differentials and total protein/albumin were determined. Lung histology was evaluated for lung inflammation or injury. BAL cells were cultured and stimulated with PBS, PMA, or LPS for 4 hours and supernatants were evaluated for cytokine content. In uninjured mice, we observed differences due to the lavage and euthanasia methods used. The lavage method increased total cells and total protein/albumin in uninjured and O₃-exposed mice, with the 800-μl instillation having the highest values. Isoflurane increased total BAL cells, whereas CO₂ euthanasia increased the total protein/albumin levels in uninjured mice. These effects limited our ability to detect differences in BAL injury measures after O₃ exposure. In conclusion, the method used for lavage and euthanasia affects measures of lung inflammation/injury and should be considered a variable in model assessments.

Investigating the Suitability of a Laboratory Mouse Model to Study the Pathogenesis of Abortifacient Campylobacter jejuni

The aim of this study was to assess whether pregnant mice represent a useful model to study the reproductive pathology of Campylobacter jejuni IA3902 using the end point of positive microbial culture of the organism from the fetoplacental unit. Pregnant BALB/c and CD-1 mice (14 days' gestation) were inoculated orally and intraperitoneally (IP) with 1 × 10⁹ colony-forming units/ml of C. jejuni IA3902. The organism was recovered by microbial culture from the fetoplacental unit in 10 of 10 BALB/c and 10 of 10 CD-1 IP-inoculated pregnant mice and in 29% (2/7) BALB/c and 38% (3/8) CD-1 orally inoculated pregnant mice. Gross reproductive lesions included necrosuppurative placentitis, fetal resorption, intrauterine fetal death, stillborn pups (dead neonates), and multifocal hepatitis. Histological changes consisted of locally extensive neutrophilic and necrotizing placentitis with intralesional bacterial colonies of C. jejuni, ulcerative endometritis, random multifocal hepatitis, and rare cholecystitis. Immunohistochemistry for the major outer membrane protein of C. jejuni revealed moderate to large numbers of the organism at the periphery of the placental discs, within trophoblasts and extracellularly, with invasion into the placental disc largely via the vascular network. The organism is trophic for neutral mucin, iron, and L-fucose within the murine placenta. C. jejuni IA3902 has affinity for the murine reproductive tract, specifically the fetoplacental unit, where it results in a necrotizing placentitis with positive microbial recovery after both IP and oral challenge in BALB/c and CD-1 pregnant mice.

Use of Renal Replacement Therapy in a Neonatal Foal with Postresuscitation Acute Renal Failure

A newborn foal was presented because it was unresponsive and in cardiopulmonary arrest. Aggressive cardiopulmonary cerebral resuscitation was administered to the foal, which revived the foal; however, acute renal failure developed. Fluid retention and azotemia occurred although the foal was alert and able to suckle. A 6‐hour renal replacement therapy session using hemodiafiltration and a continuous renal replacement therapy machine was administered to the foal at 3 days of age which lowered the foal's azotemia and facilitated removal of some of the excess body fluid. Despite therapy, the foal developed pulmonary edema and was euthanized. Although the foal in this case did not survive, this report highlights the possibility of developing postresuscitation complications such as acute renal failure and describes the use of renal replacement therapy using hemodiafiltration as a viable option in neonatal foals with acute kidney injury.

Identification and functional analysis of two toxin-antitoxin systems in Campylobacter jejuni

Toxin-antitoxin (TA) systems are widely distributed in bacteria and play an important role in maintaining plasmid stability. The leading foodborne pathogen, Campylobacter jejuni, can carry multiple plasmids associated with antibiotic resistance or virulence. Previously a virulence plasmid named pVir was identified in C. jejuni 81-176 and IA3902, but determining the role of pVir in pathogenesis has been hampered because the plasmid cannot be cured. In this study, we report the identification of two TA systems that are located on the pVir plasmid in 81-176 and IA3902, respectively. The virA (proteic antitoxin)/virT (proteic toxin) pair in IA3902 belongs to a Type II TA system, while the cjrA (RNA antitoxin)/cjpT (proteic toxin) pair in 81-176 belongs to a Type I TA system. Notably, cjrA (antitoxin) represents the first noncoding small RNA demonstrated to play a functional role in Campylobacter physiology to date. By inactivating the TA systems, pVir was readily cured from Campylobacter, indicating their functionality in Campylobacter. Using pVir-cured IA3902, we demonstrated that pVir is not required for abortion induction in the guinea pig model. These findings establish the key role of the TA systems in maintaining plasmid stability and provide a means to evaluate the function of pVir in Campylobacter pathobiology.

Histologic Features Associated with Tritrichomonas foetus-induced Colitis in Domestic Cats

Tritrichomonas foetus is a venereal pathogen of naturally bred cattle. In domestic cats, T. foetus colonizes the colon, resulting in chronic, large-bowel diarrhea. The infection is prevalent among young, densely housed cats, and there is no effective treatment. To the authors' knowledge, the characteristic microscopic lesions of T. foetus infection in naturally infected cats have not been described. The aim of the study reported here was to characterize the histologic changes in the colon of seven cats with T. foetus infection and chronic diarrhea. All cats were 1 year old or younger (mean, 6.7 ± 1.7 months), and a diagnosis of T. foetus infection was made on the basis of direct fecal smear examination (five cats), fecal culture in InPouch™ TF medium (four cats), single-tube nested polymerase chain reaction (PCR) analysis of DNA extracted from feces (two cats), or observation of trichomonads in sections of colon followed by PCR confirmation on DNA extracted from paraffin-embedded tissue (two cats). The presence of colonic trichomonads was the most diagnostic histologic feature. Organisms were identified in all cats, but in only 24 of 43 (56%) sections of colon. Trichomonads were generally present in close proximity to the mucosal surface and less frequently in the lumen of colonic crypts. The presence of colonic trichomonads was consistently associated with mild-to-moderate lymphoplasmacytic and neutrophilic colitis, crypt epithelial cell hypertrophy, hyperplasia and increased mitotic activity, loss of goblet cells, crypt microabscesses, and attenuation of the superficial colonic mucosa. In two of the cats, histologic lesions were more severe and were associated with invasion of trichomonads into the lamina propria and/or deeper layers of the colon.

A Prospective, Case Control Study Evaluating the Association between Clostridium Difficile Toxins in the Colon of Neonatal Swine and Gross and Microscopic Lesions

Clostridium difficile infection in swine has most often been described in suckling pigs, where it has been associated with mesocolonic edema and typhlocolitis. This prospective study was designed to assess the correlation between the presence of C. difficile toxins (TCd) in the colon contents of neonatal pigs and a number of parameters, including gross evidence of diarrhea, mesocoloninc edema, typhlitis, and colitis. C. difficile was isolated from 51% (66/129) of large intestines and TCd was detected in the colon contents of 50% (65/129) of the piglets. Fifty-eight percent (38/65) of TCd-positive piglets had normal to pelleted colon and rectal contents, whereas 75% (48/64) of TCd-negative pigs had gross evidence of diarrhea. Clostridium difficile toxin-positive animals were significantly more likely to have normal to pelleted feces. Edema of the mesocolon was observed in 38/65 (59%) of TCd-positive piglets. Because a high number of TCd-positive piglets (41%) lacked edema of the mesocolon and a high number of TCd-negative pigs had mesocolonic edema (51%), a statistically significant association between TCd and mesocolonic edema was not identified. Seventy-five percent (49/65) of TCd-positive piglets had colitis and 47/65 (72%) had typhlitis. The association between TCd and both colitis and typhlitis was statistically significant. Apparently healthy piglets were obtained from 5 separate sites. Because TCd was detected in the colon contents of 23/29 (79%) apparently healthy piglets obtained from 5 separate sites, and 70% of TCd-positive control pigs had colitis, C. difficile may represent an important subclinical issue in neonatal swine.

Vitamin E and Selenium Concentrations in Livers of Pigs Diagnosed with Mulberry Heart Disease

During a 2-year period from January 1, 1999, to December 31, 2000, 77 diagnoses of mulberry heart disease (MHD) were documented at the Iowa State University Veterinary Diagnostic Laboratory. Mean (±SD) liver vitamin E concentrations were lower ( P < 0.05) in pigs with MHD (3.12 ±1.12 ppm, wet weight) than in pigs that died of causes other than MHD (4.80 ± 3.2 ppm, wet weight). The majority of the pigs affected with MHD ranged in age from 3 to 7 weeks. Statistical influence of age was found on the concentration of vitamin E ( P < 0.01) but not on concentration of selenium in liver in pigs with MHD. Concentrations of vitamin E below 2 ppm were considered deficient. Hepatic vitamin E concentrations below 2 ppm were measured in 25% of the pigs with gross and microscopic lesions of MHD. In contrast, liver selenium concentrations were adequate in all pigs.

Lesion severity at processing as a predictor of Salmonella contamination of swine carcasses

OBJECTIVE

To measure the relationship between gross lesions in swine carcasses observed at a processing plant and Salmonella contamination and to determine whether nonexpert assessments of lesion status would correspond with swine pathologists' judgments.

ANIMALS

Carcasses of 202 conventionally raised and 156 antimicrobial-free pigs in a Midwestern US processing plant examined from December 2005 to January 2006.

PROCEDURES

4 replicates were conducted. For each, freshly eviscerated carcasses were identified as having or lacking visceral adhesions by a nonexpert evaluator and digital carcass photographs were obtained. Swab specimens were obtained from carcasses before the final rinse stage of processing, and bacterial culture for Salmonella spp and Enterococcus spp was performed. Subsequently, carcass photographs were numerically scored for lesion severity by 3 veterinary pathologists. Results were used to test the ability of lesion detection to predict bacterial contamination of carcasses and the agreement between judgments of the inexperienced and experienced assessors.

RESULTS

The probability of Salmonella contamination in carcasses with lesions identified at the abattoir was 90% higher than that in carcasses lacking lesions, after controlling for replicate identity and antimicrobial use. The receiver operating characteristic curve and Cohen κ indicated close agreement between lesion detection at the abattoir and by the 3 pathologists.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated the presence of lesions could be used to predict Salmonella contamination of swine carcasses and that a nonexpert processing-line assessment of lesions could be used to discriminate between healthy and chronically ill swine before their entry into the human food supply.

Myocardial toxicity in a group of greyhounds administered ractopamine

Ractopamine, a synthetic β(2)-adrenoceptor agonist, is widely used as a feed additive in the United States to promote a reduction in body fat and enhance muscle growth in cattle, pigs, and turkeys. It has the potential for illegal use in show and racing animals because it may affect performance via its β-adrenergic agonist properties or anabolic activities. Nine greyhounds were orally administered 1 mg/kg of ractopamine to investigate the ability to detect the drug in urine. Postdosing, 7 of 9 dogs developed cardiac arrhythmias and had elevated troponin levels indicating myocardial damage. One dog necropsied 4 days postdosing had massive myocardial necrosis, mild to focally moderate skeletal muscle necrosis, and widespread segmental arterial mediolysis. A second dog necropsied 17 days postdosing had mild myocardial necrosis and fibrosis. Scattered arteries exhibited segmental medial and perimedial fibromuscular dysplasia. This is the first reported case of arterial, cardiac, and skeletal muscle damage associated with ractopamine.

Comparison of two commercial ovine Campylobacter vaccines and an experimental bacterin in guinea pigs inoculated with Campylobacter jejuni

OBJECTIVE

To compare efficacy of 2 commercial ovine Campylobacter vaccines and an experimental bacterin in guinea pigs following IP inoculation with Campylobacter jejuni IA3902.

ANIMALS

51 female guinea pigs.

PROCEDURES

Pregnant and nonpregnant animals were randomly assigned to 1 of 4 treatment groups and administered a commercial Campylobacter vaccine labeled for prevention of campylobacteriosis in sheep via two 5-mL doses 14 days apart (vaccine A; n = 13), another labeled for prevention of campylobacteriosis via two 2-mL doses (vaccine B; 12), an experimental bacterin prepared from the challenge strain (12), or a sham vaccine (14). Ten days later, animals were challenged IP with C jejuni IA3902; 48 hours later, animals were euthanized, complete necropsy was performed, and blood and tissue samples were obtained for bacteriologic culture.

RESULTS

Administration of vaccine B or the experimental bacterin, but not vaccine A, significantly reduced 48-hour infection rates versus administration of the sham vaccine. A significantly reduced 48-hour infection rate was associated with administration of vaccine B independent of pregnancy status.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of vaccine B significantly reduced infection in guinea pigs challenged with C jejuni IA3902, similar to a homologous bacterin. Results suggested that vaccine B or an autogenous product may be effective in controlling ovine campylobacteriosis caused by this emergent abortifacient strain. Bacteriologic culture of blood, liver, bile, and uterus in nonpregnant guinea pigs 48 hours after inoculation may be a useful screening tool for comparing efficacy of C jejuni vaccines.

Retroperitoneal pyogranulomatous and fibrosing inflammation secondary to fungal infections in two dogs

CASE DESCRIPTIONS

A 4-year-old spayed female Golden Retriever (dog 1) was examined because of acute edema and erythema in the left hind limb and an inguinal mass, and a 5-year-old female Jack Russell Terrier (dog 2) was examined because of a recurring retro-peritoneal mass.

CLINICAL FINDINGS

Dog 1 had an edematous, hyperemic left hind limb with a fixed inguinal mass. Monocytic neutrophilic leukocytosis and hypoalbuminemia were detected. Diagnostic imaging revealed abnormal tissue surrounding the larger vessels and ureters and complete occlusion of the left limb veins. Surgery resulted in incomplete removal of the mass. Histologic examination revealed fibrosing pyogranulomatous inflammation. Results of a Histoplasma antigen test were positive, and reanalysis of the tissues revealed yeast cells indicative of Histoplasma capsulatum. Dog 2 had incomplete removal of a retroperitoneal mass. Histologic examination revealed fibrosing pyogranulomatous inflammation. The mass recurred 8 months later in dog 2; exploratory abdominal surgery at that time resulted in substantial hemorrhage from the adhered caudal aorta. Histologic examination of tissue sections from the second surgery revealed yeast cells consistent with Blastomyces dermatitidis.

TREATMENT AND OUTCOME

Both dogs had temporary improvement after surgery. Full clinical resolution required treatment for fungal disease. Dog 1 was treated with itraconazole, then fluconazole (total treatment time, 23 weeks). Dog 2 was treated with fluconazole for 36 weeks.

CLINICAL RELEVANCE

Retroperitoneal pyogranulomatous fibrosis caused by fungal infections has not been reported in veterinary medicine. There was substantial morbidity, but the prognosis can be good when this abnormality is recognized and antifungal medications are administered.

Olfactory neuroblastoma in a cat

CASE SUMMARY

A 12.5-year-old castrated male domestic shorthair cat was presented for evaluation of dyspnea. Physical examination suggested upper airway disease. Computed tomography revealed the presence of a nasopharyngeal mass. Biopsies obtained via rhinoscopy led to a diagnosis of olfactory neuroblastoma.

CLINICAL CHALLENGES

Olfactory neuroblastoma (or esthesioneuroblastoma) is a rare malignant neoplasm that arises from olfactory neuroepithelium. It was first described in human medicine in 1924. Clinical signs are variable, and diagnosis may prove challenging as this tumor, which is a differential for spontaneous intranasal tumors in cats, may be mistaken for poorly differentiated carcinomas or round cell tumors. Given its rarity, treatment options for this neoplasm have not been thoroughly evaluated and there is no standard treatment protocol.

LITERATURE REVIEW

A review of veterinary and human literature is provided, encompassing clinical signs, staging and grading systems, treatment options and prognostic factors.

Pathogenicity of an emergent, ovine abortifacient Campylobacter jejuni clone orally inoculated into pregnant guinea pigs

OBJECTIVE

To compare pathogenicity of an emergent abortifacient Campylobacter jejuni (IA 3902) with that of reference strains after oral inoculation in pregnant guinea pigs.

ANIMALS

58 pregnant guinea pigs.

PROCEDURES

12 animals were challenged IP with C jejuni IA 3902 along with 5 sham-inoculated control animals to confirm abortifacient potential. Once pathogenicity was confirmed, challenge via oral inoculation was performed whereby 12 guinea pigs received IA 3902, 12 received C jejuni isolated from ovine feces (OF48), 12 received a fully sequenced human C jejuni isolate (NCTC 11168), and 5 were sham-inoculated control animals. After abortions, guinea pigs were euthanized; samples were collected for microbial culture, histologic examination, and immunohistochemical analysis.

RESULTS

C jejuni IA 3902 induced abortion in all 12 animals following IP inoculation and 6 of 10 animals challenged orally. All 3 isolates colonized the intestines after oral inoculation, but only IA 3902 induced abortion. Evidence of infection existed for both IA 3902 and NCTC 11168; however, C jejuni was only recovered from fetoplacental units of animals inoculated with IA 3902. Immunohistochemical analysis localized C jejuni IA 3902 infection to subplacental trophoblasts, perivascular tissues, and phagocytes in the placental transitional zone.

CONCLUSIONS AND CLINICAL RELEVANCE

This study revealed that C jejuni IA 3902 was a unique, highly abortifacient strain with the ability to colonize the intestines, induce systemic infection, and cause abortion because of its affinity for the fetoplacental unit. Guinea pigs could be effectively used in the study of septic abortion after oral inoculation with this Campylobacter strain.

Neuronal vacuolation in an adult ferret

The brain of a ferret showing abnormal neurologic signs was evaluated by histopathologic, histochemical, immunohistochemical, and ultrastructural examinations. Extensive neuronal vacuolation was observed. Since the brain was negative for protease-resistant protein prion (PrP'"), it was concluded that this was not a case of transmissible spongiform encephalopathy.

Immunohistochemical evaluation of substance P and calcitonin gene-related peptide in skin and periosteum after extracorporeal shock wave therapy and radial pressure wave therapy in sheep

OBJECTIVE

To evaluate the effect of focused extracorporeal shock wave therapy (ESWT) and radial pressure wave therapy (RPWT) on immunohistochemical staining for substance P and calcitonin gene-related peptide (CGRP) in the skin and periosteum of sheep.

ANIMALS

36 sheep.

PROCEDURES

All 4 limbs of 36 sheep were treated with ESWT, RPWT, or a sham treatment. For 14 days after treatment, at least 2 sheep were euthanized daily and tissue was harvested for histologic evaluation of nerves via staining for substance P and CGRP in the skin and periosteum.

RESULTS

No effects of ESWT or RPWT were observed on the number of nerves with stain uptake for substance P or CGRP in the skin or periosteum.

CONCLUSIONS AND CLINICAL RELEVANCE

Substance P- and CGRP-containing nerve fibers are not disrupted by EWST or RPWT. Further studies are needed to identify the mechanism of analgesia observed in association with these treatment modalities.

Evaluation of analgesia resulting from extracorporeal shock wave therapy and radial pressure wave therapy in the limbs of horses and sheep

OBJECTIVE

To identify the duration and potential mechanisms of analgesia following extracorporeal shock wave therapy (ESWT) and radial pressure wave therapy (RPWT) in limbs of horses and sheep.

ANIMALS

6 horses and 30 sheep.

PROCEDURE

An electrical stimulus was used to identify the nociceptive threshold for each horse daily for 3 days before treatment (baseline) with ESWT or RPWT, 8 hours after treatment, and at 24-hour intervals for 7 days after treatment. Testing was conducted for the treatment field (midmetacarpus or midmetatarsus) and nerve field (medial and lateral forelimb heel bulbs) distal to a treatment site that included the nerve on the abaxial surface of the proximal sesamoid bone. All 4 limbs of 30 sheep were treated with ESWT, RPWT, or a sham treatment. Two sheep were euthanatized daily and tissue harvested for histologic evaluation of nerves, and concentrations of substance P and calcitonin gene-related peptide were measured in the skin and periosteum.

RESULTS

Values did not differ significantly between baseline and after treatment for the treatment field or nerve field sensation. There was a large difference in the slope when data for horses were plotted for the first 3 days after treatment, compared with the slope for days 4 to 7 after treatment. No differences were found in neuropeptide concentrations after treatment of the sheep, but there was an inflammatory response in the treated nerves.

CONCLUSIONS AND CLINICAL RELEVANCE

A small cutaneous analgesic effect may exist at the treatment site for approximately 3 days after ESWT or RPWT in horses.

Fumonisin B-glucose reaction products are less toxic when fed to swine

The effects of fumonisin B-glucose reaction products in swine diets was examined. Pigs were fed diets containing 528 micromol of total fumonisin B/kg (FB), 528 micromol of total FB-glucose adducts/kg (FB-G, 122 micromol of unreacted FB/kg), or 0 micromol of total FB/kg for 15 days to test the efficacy of the FB-G reaction products in detoxifying FB. Weight gain in FB pigs was lower than in FB-G or controls, which was correlated with feed intake reduction in FB pigs. Serum aspartate aminotransferase, gamma-glutamyltransferase, and total bilirubin in FB pigs were higher than in FB-G or control pigs. Serum sphinganine/shingosine ratios in FB pigs were higher than in FB-G or control pigs. Microscopic examination of tissues from FB pigs showed generalized liver necrosis and apoptosis with marked cellular pleomorphism and disorganized hepatic cords. The liver and kidneys in the FB-G group appeared to be normal. Tissues of controls were free of lesions. Results suggest that dietary FB-G products are less toxic to swine and may provide an detoxification approach in instances of widespread FB grain contamination (p < 0.05).

Glucose reaction with fumonisin B1 partially reduces its toxicity in swine

Acute and subacute intraperitoneal doses of fumonisin B(1) (FB(1)) were administered to test the efficacy of the FB(1)-glucose reaction products in detoxifying FB(1) in swine. In the acute study at 11 mumol of FB(1)/kg of body weight, five of six pigs administered FB(1) and four of six pigs administered FB(1)-glucose died from acute pulmonary edema. Analysis of weight gain, serum aspartate aminotransferase and gamma-glutamyltransferase, total cholesterol, and pathological evaluation did not provide evidence of protection against FB(1) toxicity by the FB(1)-glucose reaction products. In the subacute study at 5.5 mumol of FB(1)/kg of body weight, one pig administered FB(1) died from liver damage. Analysis of serum aspartate aminotransferase, gamma-glutamyltransferase, and total bilirubin showed protection against FB(1) toxicity by the FB(1)-glucose reaction products. The levels of sphinganine and sphinganine/sphingosine ratios in serum and liver as well as pathologic findings provided definitive evidence of protection against the FB(1) toxic effects by this detoxification procedure (p < 0.05).

Clinical coccidiosis in a boar stud

This report describes an outbreak of coccidiosis in a boar stud. A live, untreated, adult boar with a history of diarrhea was submitted to the Iowa State University Veterinary Diagnostic Laboratory, Ames, IA. For a 3-month period, approximately 40% of the boars in this stud had developed gray to brown diarrhea that lasted 1-3 days. Affected boars did not lose condition, and antibiotic therapy did not appear to affect the clinical course ofthe disease. At necropsy, the distal ileum was palpably thickened and covered by a thick, yellow-green, fibrinous exudate. Microscopic changes in the ileum consisted of an erosive enteritis associated with the presence of numerous coccidia within mid to superficial villus enterocytes. The mucosa was covered by a fibrinous exudate admixed with numerous nonsporulated coccidian oocysts. A light growth of Salmonella enterica serovar Derby was isolated from the small intestine of this animal, but laboratory tests were negative for Lawsonia and Brachyspira spp. Individual or paired fecal samples were obtained from 6 additional boars experiencing similar clinical signs. Numerous Eimeria spinosa oocysts were identified in these samples. Neither Salmonella nor Brachyspira spp. were cultured from submitted fecal samples. Necropsy of a live boar and examination of feces from 6 additional animals confirmed that the mild, sporadic, transient diarrhea in this boar stud was due to coccidiosis.

Porcine circovirus type 2 (PCV-2) coinfections in US field cases of postweaning multisystemic wasting syndrome (PMWS)

The prevalence of different pathogens detected in combination with porcine circovirus type 2 (PCV-2) was studied retrospectively in field cases of postweaning multisystemic wasting syndrome (PMWS) diagnosed at the Iowa State University Veterinary Diagnostic Laboratory, Ames, Iowa, between January 2000, and September 2001. The presence of PCV-2 antigen in lymphoid tissues and/or lung, demonstrated by immunohistochemistry, together with moderate to severe lymphoid depletion and/or granulomatous lymphadenitis, was used as the criteria for the diagnosis of PMWS. A total of 484 cases fulfilled these criteria. Most of the cases (294/369) of PMWS occurred in pigs between the ages of 8 and 18 weeks, with a peak at 10 weeks of age. Porcine reproductive and respiratory syndrome virus was detected in 51.9% of the cases, Mycoplasma hyopneumoniae in 35.5%, bacterial septicemia in 14.0%, bacterial pneumonia in 7.6%, swine influenza virus in 5.4%, and PCV-2 alone in 1.9%. In cases with bacterial septicemia the most frequently isolated pathogen was Streptococcus suis. In cases with bacterial pneumonia, Pasteurella multocida was the most prevalent.

A comparison of virus isolation, immunohistochemistry, fetal serology, and reverse-transcription polymerase chain reaction assay for the identification of porcine reproductive and respiratory syndrome virus transplacental infection in the fetus

Virus isolation (VI), immunohistochemistry (IHC), fetal serology, and reverse-transcription polymerase chain reaction assay (RT-PCR) were performed on samples from 107 fetuses comprising 10 litters taken from sows experimentally infected with porcine reproductive and respiratory syndrome virus (PRRSV). In addition to comparing the relative sensitivity and specificity of each test, RT-PCR was evaluated with respect to the relative suitability of thoracic fluids and tissues as samples, the effects of autolysis, and the effects of pooling of fetal specimens. VI, IHC, and fetal serology identified PRRSV infection in 48.6%, 23.4%, and 14.9% of 107 fetuses, respectively, and identified at least 1 infected fetus in 10, 10, and 5 of 10 litters, respectively. In utero death with autolysis reduced the test efficacy of all 3 methods. Fetal thoracic fluid and tissues were equally suitable for RT-PCR detection of PRRSV. Pooling fetal tissues or fluids from VI-positive animals with comparable material from negative controls had no detrimental effect on RT-PCR results when evaluated at dilutions of 1:1, 1:2, 1:4, and 1:8. The results of RT-PCR testing were positive in 100%, 94.4%, and 83.3% of VI-positive specimens allowed to autolyze at 4, 21, or 37 C, respectively, for 24, 48, and 96 hours. Compared with the other testing modalities, RT-PCR appeared to be impacted the least by the adverse effects of autolysis.

The diagnostic sensitivity of immunohistochemistry for the detection of porcine reproductive and respiratory syndrome virus in the lung of vaccinated and unvaccinated swine

Immunohistochemistry (IHC) is used routinely to detect porcine reproductive and respiratory syndrome virus (PRRSV) in the lung of nursery and grow/finish pigs with respiratory disease and has been reported to be highly specific (100%) but only moderately sensitive (67%). When multiple sections of lung are examined from field cases of porcine pneumonia, it is common to detect PRRSV antigen in only 1 or 2 of the sections. This study was undertaken to determine the impact of the number of lung sections evaluated on the diagnostic sensitivity of IHC for the detection of PRRSV in vaccinated and unvaccinated swine. Five anterioventral sections of lung from animals experimentally challenged with PRRSV were evaluated on a single IHC slide. Utilizing a beta binomial model, observed results were used to calculate the probability of detecting PRRSV with IHC as a function of the number of lung sections assessed. Results demonstrate that the diagnostic sensitivity of PRRSV IHC is dependent on the number of lung sections examined. In unvaccinated pigs, a beta binomial model predicts that if a single lung section were evaluated, PRRSV would likely be confirmed in only 48% of infected animals, and at least 5 sections of anterioventral lung would need to be assessed to detect >90% of PRRSV-infected pigs. Vaccination resulted in significantly lower gross and microscopic lung lesion scores and significantly fewer antigen-positive cells. In vaccinated swine, the calculated probability of detecting a PRRSV-infected pig with IHC when a single lung section is evaluated was only 14%. If PRRSV is a primary concern, diagnosticians should collect at least 5 anterioventral sections of lung from each pig to be evaluated on a single IHC slide. This approach will diminish the number of false-negative results obtained with this method of antigen detection.

Effect of porcine reproductive and respiratory syndrome virus infection on the ovary and progesterone levels in third trimester pregnant sows

Porcine reproductive and respiratory syndrome virus (PRRSV) is a common cause of reproductive failure and abortion in swine. The mechanism of abortion is not fully defined, and the effect of the virus on luteal function has not been explored. In this study, we exposed late-term pregnant swine to varied doses of PRRSV strain NADC-8 and evaluated effects on ovarian function by serial determination of plasma progesterone levels and by microscopic evaluation of ovarian pathologic alterations combined with immunohistochemistry and in situ hybridization to detect PRRSV antigen. We identified no specific trend in plasma progesterone level associated with PRRSV infection status and no microscopic ovarian lesions. PRRSV antigen was not demonstrated in ovarian tissues by immunohistochemistry or in situ hybridization at necropsy 21 days postexposure. Based on these findings, it does not appear that either a direct or an indirect effect on luteal function contributes to PRRSV-induced abortion.

An autosomal recessive, lethal, neurologic disease of Gordon Setter puppies

This report details clinical, necropsy, and pedigree data on an inherited, lethal, neurologic disease of young Gordon Setters. This disorder is characterized by an early age of onset, gait and postural abnormalities, progressive weakness, and recumbency by 5-6 weeks of age. Although clinically distinctive, postmortem changes in affected pups were minimal. Gross lesions were not observed. Microscopic changes were subtle and consisted of astrocyte swelling, primarily in the cerebrocortical and cerebellar white matter, and white matter tracts of the brainstem. Immunohistochemistry for glial fibrillary acidic protein revealed a marked increase in the number and staining intensity of astrocyte cytoplasmic processes in affected pups compared with age-matched controls. Neither cerebral inflammation nor neuronal necrosis was identified. Pedigree analysis of affected litters demonstrated an autosomal recessive mode of inheritance. A diagnosis of this heritable disease should be based on the early age of onset (3-4 weeks of age), characteristic clinical signs, rapid progression to recumbency by 5-6 weeks of age, identification of swollen astrocytes primarily in the cerebellar and cerebrocortical white matter and white matter tracts of the brainstem, and the exclusion of other disease processes.

The effect of subclinical selenium toxicosis on pregnant beef cattle

A field investigation conducted by the South Dakota Animal Disease Research and Diagnostic Laboratory suggested that subclinical selenium toxicosis in pregnant cows may have contributed to an outbreak of aborted/stillborn calves in a high-selenium region of South Dakota. This study was undertaken to evaluate the relationship between abortion and subclinical selenium toxicosis in the dam and to assess the effects of subclinical selenium toxicosis on the bovine immune system. Fifteen pregnant cows were fed diets containing 0.25 (control), 6.0, and 12.0 ppm selenium beginning at 80-110 days gestation. Although selenium toxicosis has been reported to cause abortion, this study failed to reproduce abortions. A single cow in the 12-ppm selenium treatment group gave birth to a weak calf, which subsequently died. This calf had myocardial lesions consistent with those described for selenium toxicosis and had hepatic selenium levels of 9.68 ppm (wet weight). Elevated dietary selenium resulted in the depression of several leukocyte function parameters in pregnant cows. A statistically significant depression in forced antibody response was identified in both selenium-supplemented groups. A significantly diminished mitogenic response to concanavalin A and pokeweed mitogen was also observed in the 12-ppm selenium group. Although a similar pattern of depression was also observed with phytohemagglutinin, differences were not significant. These findings indicate that even in the absence of clinical alkali disease, elevated selenium levels may adversely affect both pregnancy outcome and the bovine immune system.

Identification of porcine reproductive and respiratory syndrome virus in semen and tissues from vasectomized and nonvasectomized boars

Previous studies have indicated that porcine reproductive and respiratory syndrome virus (PRRSV) can be identified in and transmitted through boar semen. However, the site(s) of replication indicating the origin of PRRSV in semen has not been identified. To determine how PRRSV enters boar semen, five vasectomized and two nonvasectomized PRRSV-seronegative boars were intranasally inoculated with PRRSV isolate VR-2332. Semen was collected three times weekly from each boar and separated into cellular and cell-free (seminal plasma) fractions. Both fractions were evaluated by reverse transcriptase nested polymerase chain reaction (RT-nPCR) for the presence of PRRSV RNA. Viremia and serostatus were evaluated once weekly, and boars were euthanatized 21 days postinoculation (DPI). Tissues were collected and evaluated by RT-nPCR, virus isolation (VI), and immunohistochemistry to identify PRRSV RNA, infectious virus, or viral antigen, respectively. PRRSV RNA was identified in semen from all vasectomized and nonvasectomized boars and was most consistently found in the cell fraction, within cells identified with a macrophage marker. Viral replication as determined by VI was predominately found within lymphoid tissue. However, PRRSV RNA was widely disseminated throughout many tissues, including the reproductive tract at 21 DPI. These results indicate that PRRSV can enter semen independent of testicular or epididymal tissues, and the source of PRRSV in semen is virus-infected monocytes/macrophages or non-cell-associated virus in serum. PRRSV-infected macrophages in semen may result from infection of local tissue macrophages or may originate from PRRSV-infected circulating monocytes or macrophages.

Persistence of porcine reproductive and respiratory syndrome virus in serum and semen of adult boars

Four seronegative adult boars were intranasally inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) isolate VR-2332. Serum and semen were collected 2-3 times weekly for over 100 days postinoculation (DPI). Serum samples were assayed for PRRSV by virus isolation (VI) and a polymerase chain reaction (PCR) and screened for antibodies to PRRSV using the indirect fluorescent antibody (IFA) and virus neutralization (VN) tests. Semen was assayed for PRRSV RNA by PCR. Virus and viral RNA was detected in the serum of all boars within 1 DPI by Vi and/or PCR. However, VI results indicated that viremia was transient and occurred from 1 to 9 DPI. Viral RNA was detected in serum from 1 to 31 DPI. In the acute stage of the infection, PRRSV RNA was detected in serum by PCR prior to the presence of viral RNA in semen. The PRRSV RNA was detected in semen as early as 3 DPI and persisted for 25 DPI in 2 of the boars and 56 and 92 DPI in the remaining 2 boars. Detection of PRRSV RNA in semen occurred 2-8 and 28-35 days prior to the detection of antibodies by IFA and VN, respectively. PRRSV was isolated from the bulbourethral gland of the boar that shed viral RNA in semen for 92 DPI. These results suggest that PRRSV RNA can be detected by PCR in boar serum and semen, and may persist for variable periods of time. Viremia and the serologic status of the boar are not adequate indicators of when PRRSV or PRRSV RNA is being shed in the semen. Preliminary findings also indicated that neither shipping stress nor reinoculation with homologous PRRSV resulted in viremia or viral RNA shedding in semen.

Detection of porcine reproductive and respiratory syndrome virus in boar semen by PCR

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a devastating disease in swine. The presence and transmission of PRRSV by boar semen has been demonstrated by using a swine bioassay. In this assay, 4- to 8-week-old pigs were inoculated intraperitoneally with semen from PRRSV-infected boars. Seroconversion of these piglets indicated the presence of PRRSV in semen. Seroconversion in gilts has also been demonstrated following artificial insemination with semen from PRRSV-infected boars. These methods of detecting PRRSV in boar semen are time-consuming, laborious, and expensive. The objective of this study was to develop a reliable and sensitive PCR assay to directly detect PRRSV in boar semen. Primers from open reading frames 1b and 7 of the PRRSV genome were used in nested PCRs. Virus was detected at concentrations as low as 10 infectious virions per ml in PRRSV-spiked semen. Specificity was confirmed by using a nested PCR and a 32P-labeled oligonucleotide probe. The primers did not react with related arteriviruses or other swine viruses. The PCR assay showed good correlation with the swine bioassay, and both methods were superior to virus isolation. To consistently identify PRRSV in boar semen, the cell fraction was separated by centrifugation at 600 x g for 20 min, a lysis buffer without a reducing agent (2-mercaptoethanol) was used, and nondiluted and 1:20-diluted cell fractions were evaluated by PCR. PRRSV was not reliably detected in the seminal plasma fraction of boar semen.

The use of nerve growth factor as a reverse transforming agent for the treatment of neurogenic tumors: in vivo results

The rationale behind the evaluation of natural differentiating agents, such as nerve growth factor (NGF), for reverse transforming potential is based on the theory that such compounds may represent a nontoxic means of controlling tumor growth. Previous in vitro experiments have shown that NGF is capable of retarding growth and of inducing persistent differentiation of neurogenic tumor cell lines. In vivo, NGF is capable of causing a persistent reduction in the number of ethylnitrosourea-induced neurinomas and of increasing survival time following intracerebral implantation of F98 anaplastic glioma cells. In this study, anaplastic glioma and neurinoma implants were treated with NGF to evaluate the reverse transforming potential of NGF in vivo. Results indicate that NGF is capable of causing a significant decrease in the growth rate of subcutaneous T9 (anaplastic glioma) and clone 16 (anaplastic neurinoma) implants. Significantly, NGF treatment was accompanied by adverse effects that were minimal and transient. Continued tumor growth (although greatly retarded) following NGF treatment is an aspect that requires further investigation. However, the results of this study suggest that NGF may prove useful, alone or in combination with other types of therapy, for the treatment of tumors of neurogenic origin.

The reverse transforming effects of nerve growth factor on five human neurogenic tumor cell lines: in vitro results

The role of nerve growth factor (NGF) in the development, maintenance and regeneration of the mammalian sensory and sympathetic nervous systems has been well characterized, as has the ability of NGF to induce a variety of neoplastic cell lines of neuroecto-dermal (neurogenic) origin to differentiate. The ability to stimulate neoplastic cells of neurogenic origin to differentiate suggests that NGF may prove useful as a reverse transforming agent for the treatment of neurogenic tumors. Five human neurogenic tumor cell lines were evaluated for their response to NGF in vitro to determine whether the NGF is capable of inducing changes consistent with a reverse transforming response. Results indicate that NGF was able to reverse some of the transformed properties of these tumor cell lines, as NGF treatment stimulated neoplastic cells to develop a more differentiated phenotype, diminished or arrested growth, and induced changes that were persistent.

Immunohistochemical characterization of rat central and peripheral nerve tumors induced by ethylnitrosourea

Ethylnitrosourea-induced central and peripheral nerve tumors in Sprague-Dawley rats were tested for GFAP (Glial Fibrillary Acidic Protein), S-100 protein, NSE (Neuron Specific Enolase) and Anti-Leu 7 (HNK-1) immunoreactivity utilizing the ABC method (avidin-biotin-complex) for GFAP, S-100 protein and NSE, and the PAP method (peroxidase-antiperoxidase) for Anti-Leu 7. Peripheral nerve neurinomas were consistently positive for S-100 protein and consistently negative for GFAP and Anti-Leu 7. Neurinomas would occasionally exhibit positive staining for NSE (2 of 55 tumors). The staining intensity for S-100 protein varied from strongly positive in differentiated neurinomas to weakly positive in anaplastic tumors. Neoplastic and reactive astrocytes exhibited positive staining for both S-100 protein and GFAP. Variation in the GFAP staining intensity of glial tumors correlated with the degree of differentiation as anaplastic tumors did not stain with the same intensity as their more differentiated counterparts. Oligodendrogliomas exhibited occasional immunoreactivity to S-100 protein (3 of 36 tumors). NSE reactivity in oligodendrogliomas was rarely observed (1 tumor in 36) and immunoreactivity against GFAP or Anti-Leu 7 was consistently absent. Anti-Leu 7 and NSE proved to be of little value in the classification of ENU-induced neural tumors.