Risk factors for the detection of Salmonella in ileocolic lymph nodes in US slaughtered pigs.

Salmonella harborage at slaughter can be viewed as a nsk for human health through contammation of the pork food cham. Better understanding of herd level factors associated with this harborage would be useful to prioritize further study of epidemiology and control of Salmonella in pork production. Ileocolic lymph node samples collected at slaughter from 115 Midwest US sw1ne herds were assayed for Salmonella entenca. A subset of these herds was collected sequentially one or two additional times. Herd characteristics and management factors were assessed by a written survey. Risk factors were screened at the univariate level (p \u3c 0.3), then offered for Inclusion by stepw1se analysis including herd I sample as a random statistical effect. Pigs at increased risk of Salmonella harborage at slaughter included those placed in finisher barns at heaver weights (OR 1.2 per 10 kg Increased we1ght), those from larger herds (OR 2 0 comparing upper quintile to lower quintile of herd size), those from herds that allowed VISitors w1th recent (\u3c8 h) contact with other herds (OR 2.2), or those fed pelleted feeds (OR 2.1 ). Further invest1gat1on of these risk factors and potential biological mechanisms will requ1re further study

Epstein-Barr virus infections and DNA hybridization studies in posttransplantation lymphoma and lymphoproliferative lesions: The role of primary infection

Fourteen patients who developed B cell lymphomas or lymphoproliferative lesions after kidney, liver, heart, or heart-lung transplantation in Pittsburgh during 1981-1983 had active infection with Epstein-Barr virus (EBV)of the primary (six patients), reactivated (seven patients), or chronic (one patient) type. In transplant patients without tumors, the incidence of EBV infection was 30% (39 of 128). Only three of these patients had primary infections. Thus the frequency of active infection was significantly higher in patients with tumors, and patients with primary infections were at greater risk of developing tumors. Five of 13 tumors tested contained EBV nuclear antigen (EBNA) and nine of 11 contained EBV genomes detected by DNA-DNA hybridization with BamHI K, BamHI W, or EcoRI B cloned probes. All EBNA-positive tumors, except one, were also positive by hybridization. Only one tumor was negative for both EBNA and EBV DNA. These data suggest that EBV plays an etiologic role in the development of these lesions. © 1985 by The University of Chicago

Reversibility of lymphomas and lymphoproliferative lesions developing under cyclosporin-steroid therapy

Post-transplant lymphomas or other lymphoproliferative lesions, which were usually associated with Epstein-Barr virus infections, developed in 8, 4, 3, and 2 recipients, respectively, of cadaveric kidney, liver, heart, and heart-lung homografts. Reduction or discontinuance of immunosuppression caused regression of the lesions, often without subsequent rejection of the grafts. Chemotherapy and irradiation were not valuable. The findings may influence policies about treating other kinds of post-transplantation neoplasms

Insights on localized and systemic delivery of redox-based therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redoxbased interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside

A multifactorial system for equitable selection of cadaver kidney recipients

During 1986, a total of 270 cadaver renal transplantations were performed at the University of Pittsburgh. Kidneys were allocated by a point system that awarded points to recipients for waiting time, antigen matching, antibody analyses, medical urgency, and logistic practicality. Kidneys were given to patients with the highest point totals in 98% of cases. To our knowledge, this is the first such multifactorial system for cadaver kidney allocation. Possibly it may be modified for extrarenal organs

The effect of feed withdrawal on the shedding of Salmonella typhimurium by swine

This project was designed to determine if feed withdrawal in conjunction with transportation-related stress caused increased shedding of Salmonella by carrier pigs. In this experiment, 48 pigs were challenged orally with S. typhimurium after weaning and allowed to grow under typical production practices. Antibiotics were not included in feeds. At monthly intervals, fecal and serum samples were collected from each pig. All pigs shed the challenge organism at least once during the experiment. By the sixth month, most pigs were negative for the challenge organism when cultured from feces. When pigs reached market weight (-240 pounds), they were split into 4 groups and subjected to one of the following feed withdrawal protocols: group I had no feed withdrawal, groups 2-4 had feed withdrawn at 6, 12 or 24 hours, respectively. Pigs in each group were transported -225 kilometers (4 hours), returned to the production facility and necropsied. Contents at the ileal-cecal junction were collected and cultured for the test organism. There was a direct correlation between the time of feed withdrawal and the number of pigs with S. typhimurium in intestinal contents. Pigs that had no feed withdrawal had the fewest number of positive pigs, whereas pigs that were off feed for 24 hours had the highest number of positive pigs. Serum samples were assessed using a mixed ELISA to detect antibodies against Salmonella. All pigs had detectable antibodies. Over the various bleedings, most pigs exhibited increases in anti-Salmonella antibodies over time. Some had modest drop-offs at the later times. In about I 0% of pigs, there was no increase or decrease in anti-Salmonella antibodies. In these non-responding pigs, the specific titers were lower than responding pigs, and above background levels. The results from this experiment complement our previous work and demonstrated that feed withdrawal when in conjunction with shipping contributes to shedding of Salmonella by pigs. Most pigs were not shedding the challenge organism just prior to slaughter, yet most (\u3e80%) had persistent infections. This indicates that the detection of infected, asymptomatic carriers using conventional culture methods is difficult and could complicate plans to develop programs to certify Salmonella-free pigs

Chlorate concentration in the jejunum and cecum in growing pigs when supplemented in feed

Prior research has demonstrated that oral administration of chlorate and nitrate results in reduced risk and/or concentration of Salmonella enterica fecal shedding of infected pigs, poultry and ruminants. The effect of chlorate is concentration dependent in vitro, but the concentration of chlorate in the Gl tract has not been measured in vivo, and consequently the optimal dose of chlorate is poorly defined. We administered three dosages of chlorate (0, 40 and 120 mg/kg/day) and nitrate (0, 2 and 8 mg/kg/day) to 18 growing pigs using a 3 x 3 factorial study design. After 1 or 5 days of treatment subjects were humanely sacrificed to allow collection of jejunal and cecal content samples. The dose of chlorate and nitrate was at or doses associated with suppressed Salmonella shedding in a prior study in our lab. Samples were assayed using LC-MS-MS and chromatographic methods