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Histotripsy is a focused ultrasound technology that uses controlled acoustic cavitation to homogenize targeted tissue. We assessed local and systemic effects after histotripsy treatment with the Vortx RX® system in a canine model. The system was not approved for human use at the time of the study.Histotripsy was applied in 10 intact male dogs. The therapy transducer (36 elements, 700 kHz and 11 cm focal distance) delivered acoustic bursts (3 cycles and 500 Hz pulse repetition frequency) transabdominally to the prostate for 60 minutes. Tissue and systemic response were assessed by transrectal ultrasound, cystoscopy and interval evaluation of blood and urine parameters. Prostates were harvested on postoperative day 2 in 2 dogs and on postoperative day 28 in 8.A treatment cavity was apparent in each prostate on transrectal ultrasound and cystoscopy. Mean prostate volume decreased 36% (range 19% to 53%) by postoperative day 28. Although clinical symptoms were not produced, notable pathological findings at necropsy consisted of rectal wall muscle degeneration in 2 animals and concern for a potential histotripsy effect and 1 cm diameter areas of fibrosis in the abdominal rectus muscle in 2 animals suggestive of thermal injury along the acoustic propagation path to the prostate.Extracorporeal application of histotripsy produced prostate debulking in all dogs. Pathological findings of collateral injury are of concern since this may represent suboptimal confinement of cavitation or heating of overlying tissue. Further study is under way to quantify the prefocal thermal fields to eliminate these effects before human application.

BACKGROUND: We analyzed bacterial and fungal infectious complications in a cohort of 16 consecutive experiments with the longest surviving cardiac xenografts to date. METHODS: Transgenic, porcine-to-baboon, heterotopic (abdomen) cardiac xenotransplantation was performed in 16 consecutive experiments, using rapamycin, tacrolimus, corticosteroids, anti-CD20 monoclonal antibody, and an alpha-Gal-PEG polymer, as immunosuppression. Prophylactic anti-microbials included i.v. trimethoprim/sulfamethoxazole, oral ganciclovir/valganciclovir, and oral itraconazole. An episode of bacterial infection was defined as a positive blood and/or wound culture with: leukocytosis, fever >101.5 degrees F, and/or clinical deterioration. RESULTS: Mean graft survival was 71 +/- 29 days; the longest was 113 days. There were 23 episodes of bacterial infection; 14 resolved with treatment. The mean time to the first episode of infection was 44 +/- 21 days (n=12). Eight of 16 deaths were due to infection: two bacterial-only, two cytomegalovirus (CMV) only, four both bacterial and CMV, and none fungal. The frequency of infection was 1, 2.8, and 1.8 episodes/100 survival days, respectively, for animals whose grafts survived for 30 to 59, 60 to 89, and >90 days. CMV infection (reviewed in detail in a separate communications) was due to baboon CMV, and was associated with low serum levels of ganciclovir. CONCLUSION: In a cardiac xenograft model that achieved prolonged (>3 months) survival, bacteremia was common, but usually reversible, and fungal infection was prevented with prophylaxis. The level of immunosuppression required to achieve clinically meaningful xenograft survival is associated with a level of bacterial and fungal infectious complications that is manageable and similar to the early clinical experiences in human transplantation. Further research will determine if the viral infectious complications observed in these experiments can be reduced by optimizing blood levels of anti-viral prophylaxis and monitoring viral polymerase chain reaction levels.

Reactivation of latent porcine cytomegalovirus after coculture of peripheral blood mononuclear cells (PBMCs) from pigs with different genetic backgrounds was investigated. Nine of 10 allogeneic coculture pairs were PCR (DNA) positive, whereas 7 coculture pairs had porcine cytomegalovirus (PCMV) RNA, an indication of virus replication. The cell subpopulations harboring PCMV were monocytes and CD8 + T cells.

To further understand the effects of opiates on the pathogenesis of infectious disease, naturally occurring pathogens were studied in a swine model. Swine were given morphine for 21-42 days to establish a tolerant, dependent state. On day 7 after morphine initiation, pigs were challenged with swine herpesvirus-1 (SHV-1); on day 14, selected animals were superinfected with Pasteurella multocida. Evaluations were made of the clinical disease, protective effect of SHV-1 vaccination, and pathology. Morphine-dependent animals developed significantly greater virus-induced and secondary bacterial pneumonia. Prior vaccination with SHV-1 was not protective against pneumonia in morphine-dependent pigs. Unexpectedly, clinical signs associated with neurologic disease were less pronounced, and mortality from viral encephalitis was decreased in morphine-treated animals. Collectively, the findings demonstrate that morphine dependence is associated with a marked alteration of the pathogenesis of SHV-1 and that the effects of this opiate on pathogenesis are determined by the specific site of infection.

Functional responses to acute and chronic morphine administration in domestic swine were examined and correlated with pharmacokinetic profiles. Acute effects of morphine sulfate were monitored in pigs for 24 h and the chronic actions of morphine alkaloid were monitored for 21 days. Serum morphine levels, nociception, locomotor activity, respiratory rate, body temperature, and body weight were monitored during all studies. To assess nociception in a large laboratory animal, a portable thermal stimulating device was constructed. Morphine sulfate administered IV and SC had a half-life of approximately 1 h whereas delayed-release morphine alkaloid delivered SC had a half-life of 28 h. The degree of antinociception paralleled decline in blood morphine levels for both SC- and IV-administered animals. Tolerance occurred to both antinociception as well as weight gain despite morphine levels remaining constant over the 21-day period. Morphine dependence was demonstrated by precipitation of an abstinence syndrome using naloxone. Animals in withdrawal displayed consistent signs, including wet-dog shakes, posture changes, vocalization, and salivation. Collectively, these results indicate that swine may be reliably employed as a model to study the actions of morphine and opiate-like compounds.

Background Animal organs could satisfy the demand for solid organ transplants, which currently exceeds the limited human donor supply. Hyperacute rejection, the initial immune barrier to successful xenotransplantation, has been overcome with pig donors transgenic for human complement regulatory proteins. Delayed xenograft rejection, thought to be mediated by anti-pig antibodies predominantly to Gal antigens, is currently regarded as the major barrier to successful xenotransplantation. A median graft survival of 90 days in the life-supporting position is considered a reasonable initial standard for consideration of entry to the clinic. Methods A series of 10 heterotopic heart transplants from CD46 transgenic pigs to baboons was completed. Immunosuppression consisted of splenectomy, Rituximab (Anti-CD20), tacrolimus, sirolimus, corticosteroids, and TPC. Thymoglobulin (Rabbit Anti-Thymocyte Globulin) was used to treat putative rejection episodes. Results Median graft survival was 76 days (range 56-113 days, n = 9). Only three grafts were lost to rejection. The remaining grafts lost were due to recipient mortality with baboon cytomegalovirus (BCMV) being the major cause (n = 4). No cellular infiltrates were present as a manifestation of rejection. Three hearts showed chronic graft vasculopathy. Conclusions The median survival of 76 days in this group of heterotopic porcine-to-baboon cardiac xenografts represents a major advance over the median 27-day survival reported in the literature. Cellular rejection may not constitute a direct major barrier to xenotransplantation. A median survival of 90 days may be achievable with better control of BCMV infection. If further studies in the orthotopic position replicate these outcomes, criteria considered appropriate for clinical application of cardiac xenotransplantation would be approached.

This review on the effects of opiate use on infectious diseases discusses the complete spectrum of infections in the opiate user, including those of the lung, the GI tract, the skin, the skeletal system, and the CNS. There is both increased prevalence and increased severity of bacterial and viral infections in injection drug users with the outcome of increased morbidity and mortality. The experimental administration of opiates has lead to a greater understanding of the effects on susceptibility to and progression of infectious diseases. Animal models of opiate dependence and infection are reviewed with specific attention to cases in which the opiate-mediated effects are harmful and in which cases they are beneficial.

Swine were infected with Mycobacterium bovis to develop a model for pulmonary and disseminated tuberculosis in humans. Pigs were inoculated with various doses of M. bovis by intravenous (i.v.), intratracheal (int), or tonsillar routes. Animals were euthanized between 17 and 60 days after inoculation, and tissues were collected for culture and histopathologic examination. Lesions of disseminated tuberculosis were found in pigs given 10(4) or 10(8) cfu of M. bovis i.v. or int; localized pulmonary disease was found in pigs given 10(2) or 10(3) cfu of M. bovis int. Lesions ranged from well-organized tubercles with coagulative necrosis, epithelioid macrophages, and fibrosis to large expansive tubercles with liquefactive necrosis and extracellular growth of M. bovis. Tuberculous meningitis was observed in animals given M. bovis i.v. Swine infected with M. bovis are a useful animal model for elucidating the mechanisms of pathogenesis and host defense to tuberculosis in humans.

In the U.S., an estimated 2 million individuals have used heroin, including 600,000 on a daily basis [1]. Other opiate drugs are used medically in the treatment of pain. The use of opiate drugs is associated with an increased incidence and/or severity of infectious disease [2, 3, 4], respiratory infections [5] and impairment of cell-mediated immunity [6, 7, 8, 9]. Efforts to determine the effect of opiate drugs on immune response in humans is confounded by polydrug abuse and the effects of poor nutrition and poor hygiene. Therefore, we established a swine model of chronic morphine treatment that demonstrates tolerance and dependence in order to test the effect of opiate drugs on primary and recall immune responses [10]. Swine are suitable for chronic, longitudinal studies requiring repeated sample collection and can be trained to minimize handling stress.

Studies were performed to evaluate the effects of either acute or chronic morphine exposure on histamine release in vivo and supporting studies in vitro. In order to effectively assess histamine release in swine, studies were undertaken to evaluate the effectiveness of compound 48/80 as an intradermal skin test and determine its ability to release histamine in swine cells. Compound 48/80 skin testing was found to be a useful measure of histamine release in swine as evidenced by dose dependent wheal and flare reaction in vivo and histamine release from swine cells in vitro. Acute effects of morphine were determined on swine administered a single injection of morphine alkaloid. Skin tests using intradermal compound 48/80 and histamine, were performed using compound 48/80 both prior to, and 24 h following initiation of morphine treatment. Morphine tolerant swine were subjected to in vivo skin tests and the resulting wheal and flare responses measured. In select swine skin samples from the test sites were measured for mast cell numbers. Swine dermal mast cells were found to release histamine in a dose dependent manner upon compound 48/80 exposure. Both acute and chronic morphine-treated swine had significantly depressed responses to compound 48/80, however this difference was not due alteration in mast cell number or morphology, and skin responsiveness to histamine remained intact.

Objectives Transplantation is limited by a lack of human organ donors. Organs derived from animals, most likely the pig, represent a potential solution to this problem. For the heart, 90-day median graft survival of life-supporting pig hearts transplanted to nonhuman primates has been considered a reasonable standard for entry into the clinical arena. Overcoming the immune barrier to successful cardiac xenotransplantation is most appropriately first explored with the non–life-supporting heterotopic model. Methods We performed a series of 7 heterotopic heart transplantations from CD46 transgenic pigs to baboons using a combination of therapeutic agents largely targeted at controlling the synthesis of anti-pig antibodies. Rituximab (anti-CD20) and Thymoglobulin (rabbit antithymocyte globulin [ATG]; SangStat Medical Corp, Fremont, Calif) were used as induction therapy. Baseline immunosuppression consisted of splenectomy, tacrolimus, sirolimus, steroids, and TPC (an anti-Gal antibody therapeutic). Rejection events were not treated. Results By using Kaplan-Meier analysis, median graft survival was 96 days (range, 15–137 days; 95% confidence interval, 38–99 days). Only 2 grafts were lost as a result of rejection, as defined by cessation of graft palpation. There was no evidence of a consumptive coagulopathy, infectious complications were treatable, and no posttransplantation lymphoproliferative disorders occurred. No cellular infiltration was observed. Conclusions This study reports the longest median survival to date (96 days) of pig hearts transplanted heterotopically into baboons. Duplication of these results in the orthotopic life-supporting position could bring cardiac xenotransplantation to the threshold of clinical application.