HESI/FDA workshop on immunomodulators and cancer risk assessment: Building blocks for a weight-of-evidence approach

Profound immunosuppression (e.g., AIDS, transplant therapy) is epidemiologically associated with an increased cancer risk, and often with oncogenic viruses. It is currently unclear how broadly this association translates to therapeutics that modulate immunity. A workshop co-sponsored by the FDA and HESI examined how perturbing the immune system may contribute to carcinogenesis, and highlighted priorities for improving non-clinical risk assessment of targeted immunomodulatory therapies. Conclusions from the workshop were as follows. 1) While profound altered immunity can promote tumorigenesis, not all components of the immune system are equally important in defense against or promotion of cancer and a similar cancer risk for all immunomodulatory molecules should not be assumed. 2) Rodent carcinogenicity studies have limitations and are generally not reliable predictors of cancer risk associated with immunosuppression. 3) Cancer risk needs to be evaluated based on mechanism-based weight-of-evidence, including data from immune function tests most relevant to tumor immunosurveillance or promotion. 4) Information from nonclinical experiments, clinical epidemiology and immunomodulatory therapeutics show that immunosurveillance involves a complex network of cells and mediators. To support a weight-of-evidence approach, an increased focus on understanding the quantitative relationship between changes in relevant immune function tests and cancer risk is needed.

p53 regulates a non-apoptotic death induced by ROS

DNA damage induced by reactive oxygen species and several chemotherapeutic agents promotes both p53 and poly (ADP-ribose) polymerase (PARP) activation. p53 activation is well known to regulate apoptotic cell death, whereas robust activation of PARP-1 has been shown to promote a necrotic cell death associated with energetic collapse. Here we identify a novel role for p53 in modulating PARP enzymatic activity to regulate necrotic cell death. In mouse embryonic fibroblasts, human colorectal and human breast cancer cell lines, loss of p53 function promotes resistance to necrotic, PARP-mediated cell death. We therefore demonstrate that p53 can regulate both necrotic and apoptotic cell death, mutations or deletions in this tumor-suppressor protein may be selected by cancer cells to provide not only their resistance to apoptosis but also to necrosis, and explain resistance to chemotherapy and radiation even when it kills via non-apoptotic mechanisms.

Survival of Avian Influenza Virus H7N2 in SPF Chickens and Their Environments

The survival or clearance of the avian influenza virus (AIV) of subtype H7N2 in its chicken host was evaluated using experimentally infected specific pathogen free (SPF) chickens of different age groups. Birds of different ages were successfully infected with infectious doses ranging between 10(4.7) and 10(5.7) ELD50 per bird. In infected birds, the infective virus was undetectable usually by the third week following exposure. The infectivity or inactivation time of the H7N2 AIV in various environmental conditions was studied using chicken manure, heat, ethanol, pH, and disinfectants. The H7N2 AIV was effectively inactivated by field chicken manure in less than a week at an ambient temperature of 15-20 degrees C. At a pH 2, heating at 56 degrees C, and exposure to 70% ethanol or a specific disinfectant, the AIV infectivity was destroyed in less than 30 min.

Nephropathogenic infectious bronchitis in Pennsylvania chickens 1997-2000

Nephropathogenic infectious bronchitis (NIB) was diagnosed in 28 infectious bronchitis virus (IBV)-vaccinated commercial chicken flocks in Pennsylvania from December 1997 to July 2000. Early dinical signs were increased flock mortality and urinary water loss (polyuria and pollakiuria) leading to wet litter. Daily mortality ranged from 0.01% in layers to 2.45% in broilers, with total broiler mortality as high as 23%. Severe renal swelling and accumulation of urates in the tubules were commonly seen. Visceral gout and urolithiasis were less frequently observed. Histopathologic changes included characteristic tubular epithelial degeneration and sloughing with lymphoplasmacytic interstitial nephritis. Minimal respiratory disease signs were noted in broilers. Egg production and shell quality declined in layers. Confirmatory diagnosis of NIB was made by IBV antigen-specific immunohistochemical staining of the renal tubular epithelium and virus isolation. Sequencing of the S1 subunit gene of 21 IBV isolates showed the NIB outbreak to be associated with two unique genotypes, PA/Wolgemuth/98 and PA/171/99. The cases from which the genotypes were isolated were clinically indistinguishable. The NIB viruses were unrelated to previously recognized endemic strains in Pennsylvania and were also dissimilar to each other. Genotype PA/Wolgemuth/98 was isolated almost exclusively during the first 14 mo of the outbreak, whereas PA/171/99 was recovered during the final 18 mo. The reason for the apparent replacement of PA/Wolgemuth/98 by PA/171/99 is not known.

Fluorogenic RT-PCR assay (TaqMan) for detection and classification of bovine viral diarrhea virus

A single tube fluorogenic RT-PCR-based 'TaqMan' assay was developed for detection and classification of bovine viral diarrhea virus (BVDV). TaqMan-PCR was optimized to quantify BVD virus using the ABI PRISM 7700 sequence detection system and dual-labeled fluorogenic probes. Two different gene specific labeled fluorogenic probes for the 5' untranslated region (5' UTR) were used to differentiate between BVD types I and II. Sensitivity of the single tube TaqMan assay was compared with two-tube TaqMan assay and standard RT-PCR using 10-fold dilutions of RNA. Single tube TaqMan assay was 10-100-fold more sensitive than the two-tube TaqMan assay and the standardized single tube RT-PCR. Specificity of the assay was evaluated by testing different BVD virus strains and other bovine viruses. A total of 106 BVD positive and negative pooled or single serum samples, field isolates and reference strains were tested. Quantitation of cRNA from types I and II BVD virus was accomplished by a standard curve plotting cycle threshold values (C(T)) versus copy number. Single tube TaqMan-PCR assay was sensitive, specific and rapid for detection, quantitation and classification of BVD virus.

Single-tube single-enzyme reverse transcriptase PCR assay for detection of bovine viral diarrhea virus in pooled bovine serum

A reverse transcriptase PCR (RT-PCR) was developed for use as a diagnostic screening test for the detection of bovine viral diarrhea virus (BVDV) in pooled bovine serum samples. Individual serum samples from 60 dairy cattle herds located in Pennsylvania were evaluated by the microplate virus isolation method, and pooled sera were analyzed by RT-PCR. RT-PCR was sensitive and specific and detected a single viremic serum sample in up to 100 pooled serum samples. RT-PCR analysis of pooled sera provides a rapid and cost-effective method for the screening of cattle herds for the presence of animals persistently infected with BVDV.

Immunohistochemical study of constitutive neuronal and inducible nitric oxide synthase in the central nervous system of goat with natural listeriosis

The expression of both constitutive and inducible forms of nitric oxide synthase (NOS) was investigated by immunohistochemical staining of formalin-fixed paraffin-embedded sections in normal and Listeria monocytogenes-infected brains of goats. In normal control goats, a small number of neurons showed immunoreactivity of both iNOS and nNOS, and the number of iNOS-positive neurons was higher than the number of nNOS-positive neurons. In natural listeriosis, listeria antigens were easily immunostained in the inflammatory cells of microabscesses. In this lesion, the immunoreactivity of iNOS in neurons was more intense than the control, but nNOS was not. In microabscesses, nNOS was weakly visualized in macrophages and neutrophils, while iNOS was expressed in macrophages, but not in neutrophils. These findings suggest that normal caprine brain cells, including neurons, constitutively express iNOS and nNOS, and the expressions of these molecules is increased in Listeria monocytogenes infections. Furthermore, inflammatory cells, including macrophages, expressing both nNOS and iNOS may play important roles in the pathogenesis of bacterial meningoencephalitis in goat.

Production and evaluation criteria of specific monoclonal antibodies to the hemagglutinin of the H7N2 subtype of avian influenza virus

To enhance the rapidity in diagnosing the spread of avian influenza virus (AIV) in chicken layer flocks, studies were initiated to develop more sensitive and specific immunological and molecular methods for the detection of AIV. In this study, the purification of the hemagglutinin protein (H) from field isolates of H7N2, the production of monoclonal antibodies (MAbs), and their evaluation as diagnostic reagents are reported. Hybridomas were generated by fusion of SP2/0-Ag14 myelomas and spleen cells from immunized mice. Hybridomas secreting antibodies specific for the H protein were assayed by an ELISA and cloned using limiting dilution. The MAbs produced were characterized by hemagglutination inhibition (HI), immunohistochemistry (IHC), indirect fluorescent antibody assay (IFA), Western blots, and IFA flow cytometry using various AIV subtypes (i.e., H4N2, H5N3, H7N2). Of the various MAbs assayed, 6 had consistent and reproducible results in each of the assays used. The results obtained in this investigation enhanced the usage of the MAbs to viral H protein in the surveillance of AIV in chickens.

Iron status and stores decline with age in Lewis rats

In the context of a larger study examining the interaction of vitamin A (VA) status and age on immune function, we examined age-related changes in hematologic and iron status variables in male Lewis rats. Animals were fed a nutritionally adequate purified diet containing either 0.35 (marginal), 4.0 (control) or 50 (supplemented) mg retinol equivalents (as retinyl palmitate) per kg of diet from the time of weaning until killing at 8-10 (middle-aged) or 20-22 (old) mo of age. Neither VA nor VA and age interaction effects were significant for most iron variables examined. After controlling for body weight, old rats had significantly lower hemoglobin, hematocrit and plasma iron than middle-aged rats. This decrease in hematologic and transport iron variables was not accompanied by a shift of iron into other storage compartments. Old rats also had significantly lower total iron content and iron concentration in liver, spleen and bone marrow. Hemosiderin iron in marrow smears correlated significantly (r = 0.43-0.76, P: < 0.05) with chemical estimates of iron in storage, transport and functional pools. Old rats also tended to have less stained iron in femur marrow smears. Thus, body iron in functional, transport and storage compartments, namely the liver, spleen and bone marrow, were significantly lower in old than in middle-aged rats. Although iron stores and status are usually considered to increase with advancing age, our data show a consistent pattern of lower hematologic and storage iron variables in old than in middle-aged Lewis rats. Future research is indicated to understand the biology and functional consequences of the observed age-associated decline in body iron.

Differential expression of putative transbilayer amphipath transporters

The aminophospholipid translocase transports phosphatidylserine and phosphatidylethanolamine from one side of a bilayer to another. Cloning of the gene encoding the enzyme identified a new subfamily of P-type ATPases, proposed to be amphipath transporters. As reported here, mammals express as many as 17 different genes from this subfamily. Phylogenetic analysis reveals the genes to be grouped into several distinct classes and subclasses. To gain information on the functions represented by these groups, Northern analysis and in situ hybridization were used to examine the pattern of expression of a panel of subfamily members in the mouse. The genes are differentially expressed in the respiratory, digestive, and urogenital systems, endocrine organs, the eye, teeth, and thymus. With one exception, all of the genes are highly expressed in the central nervous system (CNS); however, the pattern of expression within the CNS differs substantially from gene to gene. These results suggest that the genes are expressed in a tissue-specific manner, are not simply redundant, and may represent isoforms that transport a variety of different amphipaths.

Epitopes for chicken monoclonal antibodies in spleens of selected Japanese quail lines

A line of Japanese quail selected for high plasma cholesterol is highly susceptible to diet-induced atherosclerosis. Lymphocyte epitopes recognized by mouse anti-chicken monoclonal antibodies (c-mAb), TCR-1, TCR-2, TCR-3. CD-3, CD-4, CD-8, and BU-1a/b were reacted with spleens from quail selected for high (HL) and low (LL) plasma total cholesterol and their nonselected controls (CL). Cross reactivity to c-mAb and effect of line and gender were immunohistochemically evaluated. Chicken spleens were positive controls. Quail were immunologically stimulated with either sheep red blood cells (SRBC) or Brucella abortus 2 weeks before spleens were removed. Quail spleen epitopes of all lines recognized TCR-3 and CD-8 c-mAb, but no other c-mAb. Number of reacting cells and staining intensity to the TCR-3 c-mAb were greater in the HL than in the LL regardless of the stimulating Ag or dose used. For the CD-8 c-mAb, there were no differences among lines in birds receiving SRBC. In B. abortus-immunized birds, sex x line interactions indicated that males of the HL and CL had lower responses than females but LL males were not different than females. TCR-3 and CD8 c-mAb may be useful in studying immunological mechanisms for atherosclerosis in Japanese quail.

Myeloperoxidase activity of the large intestine in an equine model of acute colitis

OBJECTIVE

To determine whether quantification of myeloperoxidase (MPO) activity could be a useful laboratory technique to detect granulocyte infiltration in equine intestinal tissues.

SAMPLE POPULATION

Intestinal tissue (inflamed or healthy) collected from 16 age- and sex-matched Shetland Ponies.

PROCEDURE

Intestinal tissue MPO activity was determined, and histologic assessment of adjacent specimens from healthy and inflamed intestine was done.

RESULTS

Intestinal tissue MPO activity and histopathologic score increased with time after castor oil challenge and peaked at 16 hours in an equine diarrhea model in which individual ponies provided their own control tissues.

CONCLUSIONS

Intestinal tissue inflammation scores correlated positively with tissue MPO activity in adjacent specimens.

CLINICAL RELEVANCE

Tissue MPO assay may be a useful laboratory tool to quantify intestinal mucosal inflammation in ponies.

Association of elevated lymph node cell release of histamine and tumor necrosis factor with genetic predisposition to limb edema formation in dogs infected with Brugia pahangi

Brugia pahangi infection in the canine rear limb results in marked lymphatic duct and popliteal lymph node pathologic changes. Limb edema is variably associated with infection and does not correlate well with duct or node lesions. To understand the mechanisms of limb edema, lymph node cells were collected by sequential biopsy following infection and examined for production of inflammatory mediators. Lymph node cells from a litter of dogs selectively bred with a high incidence of edema formation (82%) demonstrated spontaneously released histamine and prostaglandin E2 levels higher than those of closely related nonedema-forming dogs (0-20%) and/or control dogs. These edema-forming dogs also showed elevated release of tumor necrosis factor-alpha when cells were cultured with Brugia antigen. Toluidine blue staining of infected lymph node sections revealed that the edema-forming dogs had higher numbers of mast cells than infected lymph nodes of nonedema-forming dogs.

Prevalence and etiology of gastroduodenal ulcer in HIV-positive patients: a comparative study of 497 symptomatic subjects evaluated by endoscopy

OBJECTIVE

In 497 HIV-positive (+) patients with upper digestive tract symptoms, 23 (5%) had gastroduodenal ulcers (GDU) at upper endoscopy.

METHODS

To establish the causes of GDU in this setting, 16 of these patients who had had comprehensive histological evaluation (group I) were compared with 20 HIV+ subjects with upper gastrointestinal symptoms but without ulcer (group II), and with 16 seronegative patients with GDU (group III). Eighty-one percent of group I subjects and 90% of group II patients had C3 AIDS. The presence of gastritis and Helicobacter pylori, fungi, mycobacteria, viruses (especially cytomegalovirus [CMV] and herpes simplex [HSV]), and parasites was determined in all three groups by histopathological and microbiological studies.

RESULTS

The prevalence of chronic active gastritis was 13/16 (81%) in group I, 12/20 (60%) in group II, and 15/16 (94%) in group III. It was associated with H. pylori in group III, and with opportunistic pathogens in groups I and II and with none in group III. H. pylori was detected in 5/16 patients (31%) in group I, in 12/20 (60%) in group II, and 11/16 (69%) in group III. Cytomegalovirus was histologically diagnosed in 8/16 patients (50%) in group I and in 1/20 (5%) in group II. This virus was the only factor shown to be significantly associated with GDU in these cases (p = 0.0046). Cryptosporidium was found in 2/16 (12.5%) patients in group I, in 1/20 (5%) in group II, and in none in group III. Differences between groups I and II were not statistically significant. No other organisms were observed in the three groups.

CONCLUSIONS

Gastroduodenal ulcers were infrequent in HIV+ subjects with upper digestive tract symptoms and CMV was the only organism significantly associated with GDU in HIV+ patients. Among HIV+ patients, H. pylori was an uncommon cause of ulcer. Among HIV+ subjects with ulcer, chronic active gastritis was more common than H. pylori and it was associated with other pathogens. Finally, HIV+ patients with GDU should have endoscopic biopsies to detect opportunistic infections, especially CMV, because H. pylori infection is uncommon.

Neosporosis-associated bovine abortion in Pennsylvania

Neospora caninum was found in fetal tissues of 34 of 688 cases of bovine abortion submitted to the Pennsylvania Animal Diagnostic Laboratory System during the period from May 1994 to November 1996. The aborted fetuses ranged in gestational age from 3 to 8 months. Microscopic lesions consisted primarily of encephalitis and myocarditis. A labeled (strept) avidin-biotin staining procedure using anti-N. caninum polyclonal rabbit serum revealed N. caninum organisms within the fetal brain (27 of 27), heart (10 of 13), placenta (5 of 6), kidney (2 of 2), liver (1 of 4) and skeletal muscle (1 of 1).

CD4+ cytolytic effectors are inefficient in the clearance of Listeria monocytogenes

Cytotoxic T lymphocytes (CTL) recognize and lyse target cells through the interaction of the T-cell receptor complex with the class I or class II major histocompatibility complex (MHC). The production of class I-restricted CTL has been shown to be critical to the elimination of specific pathogens including Listeria monocytogenes. However, the function of class II-restricted CTL in the clearance of intracellular pathogens is poorly understood. H-2b beta 2-microglobulin-deficient mice (beta 2M-/-) are not able to produce CD8+ CTL in response to infection with L. monocytogenes. We used this model to evaluate the efficacy of class II-restricted CTL, in the absence of a class I-restricted response, during a primary infection with L. monocytogenes. We demonstrate that, despite their effectiveness in adoptive transfer of protection, Listeria-specific CD4+ class II-restricted cytotoxic lymphocytes are ineffective in decreasing titres of L. monocytogenes in the spleen was found established infection. In beta 2M-/- mice, persistence of L. monocytogenes in the spleen was found preferentially in class II-negative cells. Surprisingly, class I-restricted CTL from C57BL/6 mice were capable of decreasing bacterial titres during an established infection even in the absence of detectable class I on the surface of cells from beta 2M-/- mice. These data strongly suggest that, in the absence of a class I-restricted response, pathogens that elicit a class II-restricted cytotoxic response may escape prompt eradication by the immune system.

Clinical presentation of experimentally induced rabies in horses

Twelve naive and nine test-vaccinated horses which developed clinical signs of rabies as a result of the required protocol of a vaccine trial were prospectively observed. Nineteen of the 21 cases were confirmed positive for rabies infection of the brain by fluorescent antibody test. The two horses with negative results had ganglioneuritis of the trigeminal ganglion or lymphocytic perivascular cuffing in the brain stem in addition to clinical signs. Average incubation period was 12.3 days and average morbidity was 5.5 days. Naive animals had significantly shorter incubation and morbidity periods (P < 0.05). Muzzle tremors were the most frequently observed (81%) and most common initial sign. Other common signs were pharyngeal spasm or pharyngeal paresis (71%), ataxia or paresis (71%), lethargy or somnolence (71%). The furious form was manifested in 43% of rabid horses and some of these furious animals initially manifested the dumb form. The paralytic form was not observed. Histopathology was characteristics for rabies. The results of this trial do not reflect on the efficacy of commercially licensed equine rabies vaccines.

Clinical features of experimentally induced rabies in cattle and sheep

A total of 20 cattle and five sheep out of a larger group of animals that were experimentally challenged with virus as part of the required protocol for a vaccine trial developed clinical signs of rabies. All five sheep and 18 of the cattle tested positive for rabies in a direct fluorescent antibody (FA) test. The remaining two cattle had suspicious FA results. Prospective observations are reported in this study. In the diseased cattle, the average incubation period was 15.1 days and the average morbidity period was 3.7 days. Of those, the naive cattle had significantly shorter incubation and morbidity periods than the test-vaccinated cattle. Major clinical signs included excessive salivation (100%), behavioural change (100%), muzzle tremors (80%), vocalization (bellowing; 70%), aggression, hyperaesthesia and/or hyperexcitability (70%), and pharyngeal paresis/paralysis (60%). The furious form of rabies was seen in 70% of the cattle. In the diseased sheep, the average incubation period was 10.0 days and the average morbidity period was 3.25 days. Major clinical signs included muzzle and/or head tremors (80%), aggressiveness, hyperexcitability, and/or hyperaesthesia (80%), trismus (60%), salivation (60%), vocalization (60%) and recumbency (40%). The furious form of rabies manifested in 80% of the sheep. Current rabies vaccines on the market contain higher effective doses than that utilized for the test vaccine and the results of this study do not reflect in any way on commercially available ruminant rabies vaccines.

Osteosarcoma eight years after total hip arthroplasty

This report presents a case of osteosarcoma of the femoral diaphysis associated with chronic stimulation of the area by an unstable femoral prosthesis after total hip arthroplasty performed 8 years previously. The pathogenesis of this transformation may be similar to that proposed for fracture-associated sarcoma. Neoplasia should be considered as a possible late complication of total hip arthroplasty.

Fusarium proliferatum culture material alters several production and immune performance parameters in White Leghorn chickens

White Leghorn Cornell K-strain chicks (3 replicates of 16 per pen) were started at Day 7 on feed amended with Fusarium proliferatum culture material containing fumonisin B1, fumonisin B2, and moniliformin at 61, 10.5, and 42.7 ppm, respectively. Observed effects on performance of treated birds included reduced feed conversion at 2 wk, and reduced body weight of males and females up to 6 wk (P < or = .05). Splenic, thymic, and liver weights, normalized for body weight, were reduced (P < or = .05) with no change in bursa of Fabricius. No significant changes were observed histologically in the spleen, bursa, kidney, heart, liver, cecal tonsils, colon, or tibia. Significant suppression in total Ig and IgG levels occurred. Macrophages from treated chicks exhibited a 34% reduction in phagocytic activity. Natural killer cell activity was not affected. These findings, which showed that Fusarium toxins alter performance and immune end points in chickens, imply that chickens exposed to mycotoxins may be more susceptible to infectious diseases.

Histopathology and epidemiology of condemnations due to squamous cell carcinoma in broiler chickens in North Carolina

Squamous cell carcinoma (SCC) lesions were confirmed by histopathology in 94% of 176 carcasses condemned for SCC during 8-hour shifts at four different processing plants. Lesions in the remaining carcasses were diagnosed as focal ulcerative dermatitis. SCC lesions were confined to the skin; no metastasis or invasion of underlying muscle was present. Monthly prevalence of SCC condemnations at processing was obtained from two plants for a 1-year period and from two additional plants for 3-year periods. Overall study prevalence of SCC varied between 0.03% and 0.09% of total condemnations. Servicemen were found not to have an effect on SCC condemnations for the only company that had these data available. Chronological trends were evaluated for SCC condemnations. A trigonometric model predicted 6-month cycles for one processing plant over a 3-year period. The same model was used to describe 6-month cycles present in the last 12 months of a 3-year observation period in a different processing plant. Chronologic trends were evaluated qualitatively for the two other processing plants.

Management of the upper anterior single-tooth osseointegrated implant: a case presentation

Successful esthetic replacement of an anterior tooth using an implant prosthesis is one of the most challenging restorations for clinicians. Osseointegration has become a predictable technique for the successful replacement of lost or missing teeth. A thorough biological understanding of the principles and technology related to this expanding discipline assists in achieving a superior result. Integrating guided bone regeneration and soft-tissue augmentation procedures facilitates matching the soft-tissue profile of the recipient site to that of the contralateral tooth. Creating the proper emergence profile can be achieved by altering the contours of the prosthesis, which provides a restoration that mimics the natural tooth. The description and application of these techniques are demonstrated in this article.

Glioma in a goat

An adult goat was examined because of behavioral changes and circling. Results of neurologic examination, CSF analysis, hematologic evaluation, and computed tomography of the brain were suggestive of an intra-axial mass. The goat was euthanatized because of worsening neurologic condition and poor prognosis. Necropsy revealed a large mass in the right cerebral hemisphere and caudal brain herniation through the foramen magnum. The mass was diagnosed as a glioma, with oligodendrocyte differentiation. Results of immunohistochemical evaluation were compatible with a malignant, poorly differentiated tumor.

Effects of neodymium:yttrium aluminum garnet laser irradiation on endometrium and on endometrial cysts in six mares

Effects of neodymium:yttrium aluminum garnet (Nd:YAG) laser irradiation on equine endometrium were evaluated in vitro and in six mares with endometrial cysts. The Nd:YAG laser was applied to six endometrial sites, in each of five uterine specimens, with power densities of 5659 to 33,954 J/cm2. Depth of tissue ablation was measured and graded on histologic sections of the tissue lesions. Power density had a significant effect on the depth of tissue ablation (p < .001). Grade 3 lesions (full-thickness ablation of the endometrium) were created with energy densities of 16,977 to 33,954 J/cm2. Six mares had endometrial cysts treated by photoablation. Two of the four mares that were reproductively sound but barren, despite appropriate breeding, produced foals after treatment. One mare remained reproductively unsound after treatment, and another mare that was treated postpartum was bred successfully.

The effect of bursectomy on natural xenoreactive antibodies and vascularized rat cardiac xenograft rejection in the chicken

The clinical application of xenotransplantation between distantly related species is currently prevented by the occurrence of hyperacute rejection (HAR). Controversy exists over the importance of natural xenoreactive antibody (NAb)-mediated activation of the classical complement pathway vs. direct activation of the alternative C pathway in this process. In order to evaluate HAR of xenografts (Xgs) in the absence of NAb, this study utilized K strain leghorn chickens that were bursectomized (Bx) on day 17 in ovo (n = 18) to prevent B cell development and production of NAb. Aged-matched untreated siblings served as controls (n = 13). Based on pretransplant antibody levels, the Bx chickens were divided into two groups: totally Bx (Total Bx, n = 9) and partially Bx (Part Bx, n = 9). Chickens then underwent heterotopic cardiac xenotransplantation using PVG rats as donors, where the Xg was connected to the circulation of the chicken recipient utilizing cannulae. For the control group, Xg survival was 28 +/- 3 min (mean +/- SEM), while Part Bx prolonged survival to 80 +/- 15 min. Total Bx extended rat Xg survival to 102 +/- 11 min, with 5 of 9 Xgs functioning well at the time of termination of the study (90-120 min). Three chickens in the Total Bx group with rat cardiac Xgs that were functioning at 120 min were given a 1 ml i.v. injection of heat inactivated control chicken serum. This led to loss of Xg function within 10 min, confirming the important role for NAb in HAR in this species combination. Histologic examination of the Xgs following perfusion revealed significant arterial endothelial injury in the control and Part Bx groups but not in the Total Bx group. Conversely, Xgs from the Total Bx group showed marked venous congestion, which was not seen in the other two groups. This study demonstrates that: (1) Bx effectively eliminates NAb; (2) Xg survival is significantly prolonged in the absence of NAb in this rat-to-chicken xenogeneic combination; (3) the presence of NAb is associated with arterial endothelial injury; and (4) in the absence of NAb, marked venous congestion and injury occurs, which is possibly mediated by alternative C pathway activation or other humoral mechanisms.

Stable transfection of reticuloendotheliosis virus-transformed lymphoblastoid cell lines

Lymphoblastoid T cell lines were established by infection of chicken splenocytes with reticuloendotheliosis virus (REV). The target cells first were cultured in interleukin-containing conditioned medium or were stimulated by concanavalin A, or both. Most cell lines were T cells expressing CD3 and one of the T cell receptors, and all cell lines were positive for major histocompatibility complex (MHC) class II antigens. Several REV-transformed cell lines were stably transfected using electroporation with a selectable plasmid, pNL1, containing the neor gene. Transfected cell lines were selected using G418 and were maintained for periods up to 137 days. Transfected cell lines were susceptible to MHC class-I restricted lysis by cytotoxic T lymphocytes from REV-infected chickens.

Cytotoxic T lymphocytes in reticuloendotheliosis virus-infected chickens

Cytotoxic T lymphocytes were functionally demonstrated in spleen cells from chickens 7 days post inoculation with reticuloendotheliosis virus using a Cr-release assay. Major histocompatibility complex (MHC)-restricted cytotoxicity was demonstrated using effector and target cells from two different strains of chickens of known avian MHC haplotype. Anti-viral specificity was shown and in vivo generation of MHC-restricted cytotoxicity was evaluated. Cytotoxic T cells were distinguished from macrophages and natural killer cells. Their cytotoxicity was not antibody dependent. Higher levels of cytolysis were found with cytotoxic T cells from embryonally bursectomized vs. intact chickens over a large range of effector to target cell ratios. Using monoclonal antibodies, cytotoxic T cells were further defined as Ia+ T cells by immunofluorescence, antibody plus complement-mediated lysis of effector cells and blocking of cytolysis in the Cr-release assay.

Clinical flexibility and confidentiality: effects of reporting laws

Legal constraints upon therapeutic flexibility, resulting in breaches of confidentiality, can promote counterproductive effects upon patients and society. Conflicts can be created for mental health professionals who sometimes must choose between maximum self-protection and doing what they believe is ethical. A survey of forensic psychiatrists indicated that most believe they face ethical problems created by some ambiguities in current reporting statutes if they are interpreted to mandate reporting and warning. Emphasis is given: (1) to the ethical choice faced by therapists as to whether rigidly to report and warn to limit liability in all Tarasoff-type situations and in some ambiguous child abuse situations, or to take an alternative action when it is clinically indicated for the benefit of a patient and/or society; (2) to the importance of understanding the distinction between potential criminal liability for failure to report under many child abuse laws, and the risk only of civil liability in Tarasoff-type cases; and (3) to appreciate the flexibility permitted by current "Tarasoff" laws. Our case histories demonstrate that mandated erosion of therapeutic confidentiality can present serious problems for patients and others. Suggestions are included for modifications in the current reporting statutes, focusing on the perspective that clinical flexibility is an essential adjunct to community protection as well as to effective therapy.

Functional and biochemical characterizations of avian T lymphocyte antigens identified by monoclonal antibodies

Seven monoclonal antibodies (mAb) were used to characterize antigens present on chicken T lymphocytes and on natural killer cells by flow cytometry, radioimmunoprecipitation and by effects on cell-mediated cytotoxicity and mitogen-induced proliferation. mAb CTLA8 and 5 stained 73% of thymus, 44% of spleen and 51% of peripheral blood lymphocytes (PBL), respectively, and immunoprecipitated 65- and 45-kDa proteins from detergent extracts of 125I surface-labeled thymocytes. Pretreatment of splenic lymphocytes with mAb CTLA5 and 8 in the presence of rabbit complement (C) eliminated the concanavalin A (Con A)-induced T cell proliferative responses. mAb CTLA3, 4 and 9 stained 43% of thymus, 36% of spleen and 18% of PBL, and immunoprecipitated 33-35-kDa proteins. Pretreatment of spleen cells with mAb 4 or 9 plus C reduced, but did not eliminate, the Con A-induced proliferative response and significantly reduced both major histocompatibility complex (MHC)-restricted and non-MHC-restricted cellular cytotoxicity. mAb CTLA1 and 6 stained 58% of thymus, 13% of spleen and 19% of PBL. mAb CTLA1 and 6 immunoprecipitated a 65-kDa protein. mAb CTLA1 and 6 had no effect on the Con A-induced blastogenesis and CTLA6 caused no decrease in virus-specific cytotoxic T lymphocyte and natural killer activity. These results indicate that (a) mAb CTLA5 and 8 identify antigens on mature T lymphocytes that are similar in tissue distribution, molecular mass and function to the mammalian CD5 antigen; (b) mAb CTLA3, 4 and 9 detect the avian homologue of CD8 antigen; and (c) mAb CTLA1 and 6 identify the avian homologue of CD4 antigen.

Child abuse reporting trends: an unprecedented threat to confidentiality

Some recent interpretations of the child abuse laws are creating serious and unprecedented erosions of therapist/patient confidentiality. In contrast to the Tarasoff decisions and laws, the child abuse statutes introduced a new element of mandatory reporting which permits no discretionary alternatives and presents prospects of criminal penalties for failure to report. A recent development suggests a possible requirement for therapists to violate confidentiality for the sole purpose of punishing perpetrators. Overinterpretations of the laws by some child protective services have led to recommendations that long past child abuse must be reported, even when no current child is in danger. The California Attorney General's Office has issued a clarification stating that the child abuse statute refers to children and not to adults molested as children. A survey of forensic psychiatrists and psychologists shows that most perceived an ethical problem in reporting adults molested as children when no child is presently in danger, and the purpose of the report is solely for maximal legal self-protection. The survey indicates that fears induced by rigid and intimidating child abuse laws can influence therapists to act in ways most consider unethical. Recommendations are made for improving the current child abuse laws so that they accomplish their goals more effectively.

Bovine abortion caused by Bacillus cereus

Bacillus cereus was identified as an infrequent abortigenic agent in cattle. Necrotizing placentitis with no or sporadic lesions in fetal tissues was seen. Bacillus cereus was isolated in pure culture from fetal tissue and/or placenta. The recent identification of a bovine abortion caused by B cereus, prompted a retrospective survey of the pathology files. Eight of 947 bovine abortions were attributed to B cereus. Bacillus cereus is often mistaken as a contaminant in bovine abortion because of the failure to identify lesions in fetal tissues compatible with bacterial invasion. A necrotizing toxin may be responsible for the placentitis, with expulsion of the fetus before bacterial colonization.

Traumatic dislocation of the atlanto-occipital articulation (AOA) with short-term survival. With a radiographic method of measuring the AOA

Three patients with traumatic atlanto-occipital articulation (AOA) dislocation are presented, and an additional 10 well documented cases are reviewed from the literature. Medulla oblongata and/or spinal cord deficits, and evidence of cranial nerve injuries were noted in eight patients. Angiographic evidence of vertebral occlusion or narrowing was demonstrated in four patients. One patient had systemic hypertension, presumably from bilateral traumatic ninth nerve injuries. Five patients ultimately died. A new method of measuring the AOA is introduced.