New results with the Zenith graft in the treatment of aortic aneurysms.

Aneurysmal disease of the arterial vasculature has been reported since ancient times. Regarding aneurysms of the aorta, a steady progress has been made ranging from making such pathology amenable to surgical treatment to making the procedure much less invasive. There have been a number of stent grafts, introduced by different companies, used to exclude different segments of the aneurysmal aorta and the Zenith devices are one of them. The safety and efficacy of these devices to exclude infrarenal and descending thoracic aortic aneurysms has been well documented. The early and late complications associated with these procedures and the methods used to manage such complications have also been elucidated in different publications. In dealing with pararenal and thoracoabdominal aneurysms, the need to ensure patency of the visceral vessels while still repairing the aorta to healthy tissue must be considered. Strategies involving fenestrations and side-arm branches have evolved extending the ability to treat the entire aorta with an endovascular approach. Challenges exist including the inherent tortuosity and mobility of the aortic arch, close approximation of the supra-aortic vessels, small or multiple renal vessels, the commonly noted arcuate ligament compression of the celiac artery, but great strides have been made and virtually all pathologies have been addressed. The desire for smaller delivery systems has spurred interest in low-profile devices. This manuscript is intended to address the latest developments and clinical results for endovascular grafting of the aorta.

Anorectal anomalies in adult females corrected by posterior sagittal anorectoplasty.

Posterior sagittal anorectoplasty (PSARP) is preferred by most pediatric surgeon and intermediate types of anorectal anomalies (ARA) in infants. In this report, we describe two girls who presented in their late teens with ARA and were treated by PSARP. Prior to this report, only two adult females with congenital rectovaginal fistulae treated by PSARP have been reported. Megarectum is a feature in late presentation of ARA and requires rectal tapering during PSARP. The functional outcome in late presentation of ARA is discussed.

A comparison of the immune response of a 2001 commercial broiler with a 1957 randombred broiler strain when fed representative 1957 and 2001 broiler diets.

Immunocompetence of the 2001 Ross 308 broiler strain and the 1957 Athens Canadian Randombred Control (ACRBC) strain was compared when they were given diets representative of those that were being used in 1957 and 2001. Antibody response against SRBC, in vivo lymphoproliferation against Phytohemagglutinin-P (PHA-P), and inflammatory and phagocytic responses of the macrophages were measured. The Ross 308 strain on the 2001 diet had higher BW at 24 d of age (P = 0.0001), whereas the ACRBC had greater lymphoid organ weights (except thymus) relative to BW (P < or = 0.003). The ACRBC strain showed greater antibody responses against SRBC than the 2001 Ross 308 birds for much of the trial (P < or = 0.0362). However, the Ross 308 broilers had greater PHA-P-induced toe-web swelling response (P < or = 0.0129). Inflammatory exudate cell numbers were higher in the Ross 308 broilers than in the ACRBC birds (P = 0.0261). The percentage of macrophages that phagocytized SRBC was comparable between the two strains, but the number of SRBC phagocytized by individual macrophages was higher (P = 0.0122) in the Ross 308 broiler than in the ACRBC chickens. Nitrite production by macrophages following lipopolysacharide stimulation was comparable between the two strains. Interactions of diet, strain, and sex were inconsistent among all parameters tested. In conclusion, the current study suggested that genetic selection for improved broiler performance has resulted in a decrease in the adaptive arm of the immune response but an increase in the cell-mediated and inflammatory responses.

Avian macrophage and immune response: an overview.

Macrophages belong to the mononuclear phagocytic system lineage. This cell type is unique in that it is a crucial player in both the innate and adaptive immune responses. The material described in this overview is a brief description of what I presented as a World's Poultry Science Association-sponsored lecture at the annual meetings of the Poultry Science Association in 2002. Therefore, I have not attempted to present an up-to-date review of literature on this topic. Rather, I have summarized some salient research accomplishments made by our research group over the years in the area of avian macrophage biology and function.

The influence of beta-glucan on immune responses in broiler chicks.

Beta-1,3/1,6-glucan (beta-glucan) was tested as a possible immunomodulator. Chicken macrophages from a macrophage cell line MQ-NCSU and from abdominal exudate of broiler chickens were exposed to various concentrations of beta-glucan in vitro. In addition, day-old broiler chicks were fed a diet containing 0, 20, and 40 mg/kg beta-glucan in the starter and 0, 20, and 20 mg/kg in the grower diet. Several baseline immune parameters were examined following such exposures. The results showed that beta-glucan exposure increased nitrite and interleukin-1 (IL-1) production as well as induced macrophage to proliferate in culture. However, IL-6 production was not affected. Dietary beta-glucan supplementation increased the macrophage phagocytic activity, anti-sheep red blood cells antibody response post-boost, as well as the PHAP-mediated lymphoproliferative response measured as a toe-web swelling. The percentage of CD4+, CD8+, and CD4+/CD8+ double positive lymphocytes in the intestinal intraepithelial leukocytes was increased in beta-glucan supplemented chicks. Furthermore, the primary and secondary lymphoid organs such as bursa of Fabricius, thymus and spleen were larger in beta-glucan-supplemented chicks as compared to the chicks on basal diet. The findings of these studies which showed that beta-glucan improves several baseline immune responses in the chicken imply that beta-glucan can be used as a possible immunomodulator in food animals such as the chicken.

Interactions of poult enteritis and mortality syndrome-associated reovirus with various cell types in vitro.

An avian reovirus, ARV-CU98, has recently been isolated from poults experiencing poult enteritis and mortality syndrome (PEMS). To further understand ARV-CU98 and its role in PEMS, the current study investigates interactions of ARV-CU98 with various cell types in vitro. When macrophages, B cells, T cells, and liver cells of chicken or turkey origin were co-incubated with ARV-CU98, only cells of liver origin demonstrated cytopathic effects, the presence of viral antigen, and reduced metabolic activity over time. Furthermore, distinctive pockets of viral particles were evident in electron microscopic examination of a chicken hepatocellular carcinoma (LMH) cell line, but not in a chicken macrophage cell line (MQ-NCSU) co-incubated with virus. Additional evidence of viral replication in LMH, cells but not MQ-NCSU cells was demonstrated by the presence of two viral bands (43 and 145 kD size) in cell lysates from LMH cells exposed to ARV-CU98. Although not capable of being infected by ARV-CU98, MQ-NCSU cells do appear to be activated by the virus since IL-1 mRNA expression is increased in MQ-NCSU cells 2 h after addition of the virus. LMH cells exposed to the virus demonstrate a decrease in IL-1 mRNA expression by 8 to 10 h after addition of the virus, perhaps corresponding to the initiation of infection by the virus. In conclusion, this study demonstrates that ARV-CU98 actively infects and replicates in LMH cells, but not in lymphocytes or macrophages, suggesting that the liver may be a target and site of replication of ARV-CU98 in poults experiencing PEMS.

Formalin dab for haemorrhagic radiation proctitis.

BACKGROUND: Haemorrhagic radiation proctitis frequently presents as a problem in management. We analysed the technique of formalin dab in its management. PATIENTS AND METHODS: Twenty patients presenting with haemorrhagic radiation proctitis and treated with formalin dab were prospectively analysed. RESULTS: Twelve patients ceased to bleed following one session of formnalin dab. Six patients needed more than one session to effect haemostasis. Two of three patients with torrential bleeding failed to respond to formalin dab and required surgical excision of the rectum. CONCLUSION: Formalin dab is a simple, effective and safe treatment modality in the management of chronic haemorrhagic radiation proctitis, and hence should be considered as the initial treatment modality for such a condition.

Involvement of lipopolysaccharide related receptors and nuclear factor kappa B in differential expression of inducible nitric oxide synthase in chicken macrophages from different genetic backgrounds.

Macrophages from Cornell K-strain chickens (B(15)B(15)) are hyper and from GB2 chickens (B(6)B(6)) are hypo-responders to LPS-mediated inducible NOS (iNOS) expression and activity. The molecular mechanism(s) responsible for this differential expression is not yet fully understood. We have previously reported that macrophages from K (iNOS hyper-responder) and GB2 (iNOS hypo-responder) chickens differ in constitutive expression of TLR4 but not in CD14 molecules. The objectives of the current study was to determine if the iNOS differences between K and GB2 macrophages are possibly due to differential expression of LPS-induced TLR4, CD14 and/or nuclear factor kappa B (NF kappa B). The results showed that Sephadex-elicited, adherence purified K macrophages expressed more inducible TLR4 and CD14 receptors (P<0.05) at 6 and 12h post-LPS stimulation than GB2 macrophages as measured by flow cytometry. In addition, pre-incubation of macrophages from a transformed chicken macrophage cell line, MQ-NCSU, with 50 microg/ml anti-CD14 and anti-TLR4 antibodies significantly reduced where as pre-incubation with 100 microg/ml completely blocked LPS-mediated iNOS activity as measured by nitrite levels. Furthermore, the amount of nuclear bound NF kappa B was found to be significantly greater in K than in GB2 macrophages at 3 min post-LPS stimulation. This nuclear localization of NF kappa B as well as iNOS activity was completely inhibited by pretreatment of macrophages with 50 micro M MG132, a proteosome inhibitor, both in K and GB2 macrophages. Taken together, these findings suggest that a differential and perhaps more stronger LPS-mediated signaling via CD14, TLR4 and NF kappa B is responsible for the heightened iNOS gene induction in K-strain (hyper-responder) macrophages than in GB2 (hypo-responder) chickens.

Differential expression of inducible nitric oxide synthase is associated with differential Toll-like receptor-4 expression in chicken macrophages from different genetic backgrounds.

The purpose of this study was to examine iNOS gene expression and activity in macrophages from different chicken genetic lines against various bacterial LPS. Furthermore, the possible involvement of surface LPS receptors as candidates for differential iNOS gene induction in these genetic lines of chicken was also examined. Sephadex-elicited abdominal macrophages (1 x 10(6)) as well as iNOS hyper-responder macrophages from a transformed chicken macrophage cell line, MQ-NCSU, were exposed to 5 microg/ml LPS from E. coli, Shigella flexneri, Serratia marcensces, and Salmonella typhimurium. Nitrite levels were quantitated in the culture supernatant fractions of macrophages after 24h by the Griess method. The results showed that macrophages from K-strain (B(15)B(15)) (range from two separate trials: 31-89 microM) and MQ-NCSU (22-81 microM) were high responders whereas macrophages from both GB1 (B(13)B(13)) (15-38 microM) and GB2 (B(6)B(6)) (7-15 microM) chickens were low responders against all LPSs used. Northern blot analysis revealed that K-strain macrophages expressed higher intensity of 4.5Kb iNOS mRNA (iNOS/beta-actin ratio) than macrophages from GB2 regardless of the LPS source. To elucidate possible molecular mechanism(s) involved in iNOS gene expression in these two strains of chickens, the constitutive expression of LPS-related macrophage cell surface receptors, CD14, Toll-like receptor-2 (TLR2), and Toll-like receptor-4 (TLR4), was examined via flow cytometry using anti-human CD14, TLR2 and TLR4 antibodies. CD14 surface expression and intensity was not different between macrophages from K-strain or GB2 chickens. In contrast, while the overall percentage of TLR4-positive macrophages was the same (K-strain, trial 1=92%, trial 2=62%; GB2, trial 1=91%, trial 2=64%), the mean fluorescence intensity (MFI), an indicator of receptor number, was significantly higher (P=0.05) in K-strain macrophages (MFI: trial 1=145; trial 2=131) than GB2 macrophages (MFI: trial 1=101; trial 2=98). Furthermore, TLR2 (a previously thought candidate as LPS signaling molecule) positive cell numbers were higher in K-strain than the GB2 macrophages in one of the two trials with no difference in the intensity of TLR2 expression in either trial. These findings suggest that the observed differences in iNOS expression and activity among the K-strain (hyper-responder) and GB2 (hypo-responder) chickens are, at least in part, due to differential expression of TLR4 (an LPS signaling molecule), leading to more intense LPS-mediated activation of K-macrophages.

Flexible bronchoscopy in the diagnosis of pulmonary infiltrates following autologous peripheral stem cell transplantation for advanced breast cancer.

Flexible bronchoscopy is an important tool in the diagnosis of pulmonary complications following bone marrow transplantation. However, the value of this procedure in autologous peripheral stem cell transplant (APSCT) recipients with pulmonary complications is not well defined. We retrospectively evaluated the diagnostic yield of 27 consecutive bronchoscopies done on 23 APSCT recipients following high-dose chemotherapy for breast cancer. FB resulted in a positive diagnosis in 16 cases (59%). Broncheoalveolar lavage (BAL) was performed on all patients, and transbronchial biopsies (TBB) were carried out in 14. TBB were diagnostic in 10 (71%), with pulmonary drug toxicity as the most common finding (n = 8), followed by metastatic breast cancer (n = 2). BAL was diagnostic in six (22%): bacterial pneumonia (n = 3), aspergillosis (n = 2), Pneumocystis carinii pneumonia (n = 1) and Influenza B (n = 1). The procedure was well tolerated with no major complications except a small pneumothorax in one patient that did not require chest tube insertion. In conclusion, flexible bronchoscopy is a useful tool in the evaluation of pulmonary complications following APSCT for breast cancer. TBB can be done safely with relatively high diagnostic yield. Pulmonary drug toxicity is the most common pathological finding.

Enhancement of chicken macrophage phagocytic function and nitrite production by dietary Spirulina platensis.

The effects of dietary Spirulina platensis on chicken macrophage phagocytic function and nitrite production were examined. Day old broiler (meat-type) chicks were randomly assigned to various pens of electrically heated wire batteries. Dietary treatment groups included a basal diet with no dietary Spirulina added, and three additional groups with 0.5, 1.0 and 2.0% dietary Spirulina. Feed and water were provided for ad libitum consumption from one day of age. Sephadex-elicited macrophages were harvested at 14, 35 and 42 days of age. Phagocytosis assay was performed by co-incubating sheep red blood cells (SRBC) with the adherent macrophage monolayers. For nitrite quantification, macrophage cultures from various dietary treatment groups were stimulated in the presence or absence of 1 microg/mL of Escherichia coli lipopolysaccharide. These culture supernatant fractions were then tested for nitrite levels using the Greiss reagent technique. All Spirulina dietary group macrophages exhibited an enhanced phagocytic activity in terms of overall phagocytic percentage (range = 28 to 39% versus 24 to 25% in the basal group) and the average number of SRBC per phagocytic macrophage (range = 2.2 to 3.6 versus 1.8 to 2.5 in the basal group). This increase was linear with each incremental increase of dietary Spirulina. While LPS-induced nitrite levels in macrophages from basal diet group ranged from 60 to 278 microM over the three developmental ages, these levels in all Spirulina dietary groups were significantly higher (0.5% group range = 198 to 457 microM; 1.0% group range = 161 to 359 microM and 2.0% group range = 204 to 420 microM. These data clearly show that Spirulina platensis feeding upregulates macrophage phagocytic as well as metabolic pathways leading to increased nitric oxide synthase activity. These findings therefore imply that Spirulina platensis may enhance the functions of mononuclear phagocytic system thereby increasing the disease resistance potential in chickens.

Induction of functional defects in macrophages by a poult enteritis and mortality syndrome-associated turkey astrovirus.

The interaction of a poult enteritis and mortality syndrome (PEMS)-turkey astrovirus-Ohio State University (TAst-OSU) with the mononuclear phagocytic system cells, namely macrophages, was examined after in vitro and in vivo exposure. In vitro exposures were performed by incubating adherent turkey macrophages with various volumes of 10(6) 50% embryo infective dose (EID50)/ml TAst-OSU stock, whereas for in vivo challenge, poults were given a 200 microl inoculum of 10(6) EID50/ml TAst-OSU stock at 7 days of age. Results show that TAst-OSU in vitro exposure reduced macrophage viability relative to controls (P < 0.05) and decreased phagocytosis (P < 0.05) and intracytoplasmic killing of Escherichia coli (P < 0.05) after a 42-48-hr exposure. Poults challenged with TAst-OSU in vivo recruited almost 50% fewer Sephadex-elicited inflammatory cells in the abdominal cavity (P < 0.05) as compared with the sham controls. Similar to in vitro exposure, macrophages isolated from in vivo TAst-OSU-challenged poults exhibited reduced percentage of phagocytic macrophages (P < 0.05) as well as fewer intracytoplasmic E. coli per phagocytic macrophage (P < 0.05). TAst-OSU-challenged poults had a greater number of viable E. coli in their spleens (P < 0.05) after an intravenous E. coli challenge as compared with the non-TAst-OSU-challenged control poults. Macrophage-mediated cytokines and metabolites were also examined during this study. Both in vitro and in vivo TAst-OSU challenge resulted in reduced interleukin (IL)-1 and IL-6 activity. On the contrary, nitrite levels in macrophage culture supernatant fraction of TAst-OSU-challenged macrophages were significantly higher (P < or = 0.05). The findings of these studies indicated that TAst-OSU challenge induced defects in macrophage effector functions, implying that PEMS-turkey astrovirus can potentially impair the immune response of turkeys, thereby leading to enhanced susceptibility of turkeys to secondary, perhaps even fatal, bacterial infections.

A novel "small round virus" inducing poult enteritis and mortality syndrome and associated immune alterations.

The role of a novel "small round virus" (SRV) isolated from poult enteritis and mortality syndrome (PEMS) cases in inducing PEMS and associated immune alterations was examined in this study. Specific-pathogen-free and conventional poults were orally challenged with SRV and/or turkey coronavirus and monitored for clinical signs. Intestines, thymus, bursa, and spleens were examined for SRV antigen at various days postinoculation (DPI). Peripheral blood lymphocytes (PBLs), thymocytes, and splenic lymphocytes from inoculated poults or lymphocytes isolated from healthy poults after incubation with SRV in vitro were examined for lymphoproliferative potential against concanavalin A (Con A). The incidence of lymphocyte subpopulations in the peripheral blood and thymic lymphocytes of SRV-challenged poults was examined by flow cytometry. The results of these studies showed that the SRV challenge induced diarrhea, growth suppression, and atrophy of thymus and bursa resembling those of PEMS in field and/or experimental infections. The SRV antigen was detected in intestinal tissues soon after infection (i.e., at 2 and 4 DPI), whereas lymphoid tissues such as thymus, bursa, and spleen were positive for SRV antigen starting at 4 DPI until 8 DPI, suggesting virus translocation to lymphoid organs. The responsiveness of PBLs to Con A at 2 DPI was significantly reduced in all virus challenge groups (e.g., 28% and 22% in the SRV-alone group in studies 1 and 2, respectively) below the uninfected group. However, this suppressed response was no longer evident in the SRV group by 7 DPI. The SRV incubation with normal thymocytes and splenocytes in vitro resulted in significantly reduced lymphoproliferative response against Con A (41.2% and 10.49% reductions at 1:50 SRV dilution vs. controls in thymocytes and splenocytes, respectively). Flow cytometry analysis revealed a sudden decline at 2 DPI in the numbers of CD4- CD8+ lymphocyte subset in PBLs of SRV-infected poults. However, by 8 DPI, SRV-challenged poults had relatively higher CD4- CD8+ lymphocytes in PBLs. On the contrary, thymocytes had higher percentages of CD4- CD8+ lymphocytes at 2 and 4 DPI and reached comparable levels at 8 DPI in controls and SRV-infected poults. No differences were observed in CD4+ CD8- lymphocyte numbers in controls vs. SRV-infected poults. The findings of these studies imply that SRV may be a promising primary etiologic agent of PEMS. Furthermore, the SRV infection may compromise the lymphocyte-mediated immune defenses by reducing lymphoproliferation and the CD4- CD8+ (presumably T-cytotoxic cells) lymphocytes during the acute stage of SRV infection.

Alterations in macrophage-produced cytokines and nitrite associated with poult enteritis and mortality syndrome.

Poult enteritis and mortality syndrome (PEMS) is an acute, transmissible, infectious intestinal disease associated with high mortality and morbidity in turkey poults. Earlier studies demonstrated immune dysfunction, involving both humoral and cell-mediated immunity, associated with PEMS. The current study examined cytokines and metabolites produced by macrophages from poults exposed to PEMS agent(s). Six trials were conducted with six separate hatches of poults. Poults in the PEMS group were exposed to PEMS agent(s) via contact exposure at 7 days of age whereas uninfected poults served as control poults. Abdominal macrophages were harvested from control (uninfected) and PEMS poults at various times postexposure and cultured for 18-24 hr in the presence of Escherichia coli lipopolysaccharide. Interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) bioactivities and nitrite levels in macrophage culture supernatants were quantified. Macrophage supernatants from PEMS poults had greater IL-1-mediated stimulation index compared with the macrophage supernatants from uninfected control poults in both trials. However, this increase was significant only in trial 1. IL-6 activity tested in three separate trials was significantly higher in PEMS macrophage supernatants over the controls. On the contrary, TNF-alpha production by macrophages was decreased in PEMS macrophage culture supernatants. Nitrite levels in PEMS macrophage culture supernatants were significantly higher in two out of three trials. These findings suggest that the enhanced production of proinflammatory cytokine/metabolites by activated macrophages in PEMS poults may be responsible, at least in part, for the physiological intestinal inflammation, gut motility, and anorexia that characterize this disease.

Avian macrophage: effector functions in health and disease.

Monocytes-macrophages, cells belonging to the mononuclear phagocytic system, are considered as the first line of immunological defense. Being mobile scavenger cells, macrophages participate in innate immunity by serving as phagocytic cells. These cells arise in the bone marrow and subsequently enter the blood circulation as blood monocytes. Upon migration to various tissues, monocytes mature and differentiate into tissue macrophages. Macrophages then initiate the 'acquired' immune response in their capacity as antigen processing and presenting cells. While responding to their tissue microenvironment or exogenous antigenic challenge, macrophages may secrete several immunoregulatory cytokines or metabolites. Being the first line of immunological defense, macrophages therefore represent an important step during interaction with infectious agents. The outcome of the macrophage-pathogen interaction depends upon several factors including the stage of macrophage activation, the nature of the infectious agent, the level of genetic control on macrophage function as well as environmental and nutritional factors that may modulate macrophage activation and functions. Research in avian macrophages has lagged behind that in mammals. This has been largely due to the lack of harvestable resident macrophages from the chicken peritoneal cavity. However, the development of elicitation protocols to harvest inflammatory abdominal macrophages and the availability of transformed chicken macrophage cell lines, has enabled researchers to address several questions related to chicken macrophage biology and function in health and disease. In this manuscript the basic profiles of several macrophage effector functions are described. In addition, the interaction of macrophages with various pathogens as well as the effect of genetic and environmental factors on macrophage functional modulation is described.

Enhancement of cellular and humoral immunity in young broilers by the dietary supplementation of beta-hydroxy-beta-methylbutyrate.

As a dietary supplement, beta-Hydroxy-beta-Methylbutyrate (HMB), a catabolite of leucine, has been shown to reduce broiler mortality. In a series of experiments, male broilers (Experiments 1 and 2, n = 576) were grown for 21 days on diets that contained HMB at 0, 0.01. 0.05, and 0.10% of diet. In Experiment 3 (n = 240), chicks were fed diets containing 0, 0.05, 0.075, and 0.10% HMB. HMB dietary supplementation did not significantly affect broiler weight gain in any experiment. However, a trend toward increased mean broiler weight gain per bird was observed in Experiments 1 and 3 when HMB was consumed at 0.10% of the diet. Mean feed to gain ratio was not affected by the inclusion of HMB in broiler diets. In Experiment 3, HMB supplemented diets did not affect bursa of Fabricius, thymus, and spleen weights at 21 days of age. Cutaneous basophilic hypersensitivity response against pokeweek mitogen was higher (P < or = 0.05) at 48 and 72 hours post-injection in chicks on 0.05% dietary HMB (Experiment 1). In Experiment 2, this increase occurred 24 hours post-injection in chicks fed HMB at 0.01% of the diet. On the contrary, the T-cell mediated response against PHA-P mitogen was comparable between all dietary treatments in multiple experiments. Macrophage function profiles were determined at 21 days of age. All chicks in experiments 1 and 2 on HMB supplemented diets showed an increase in the recruitment of Sephadex-G50-elicited abdominal exudate cells (AEC). A 2-fold increase in AEC numbers occurred at the 0.10% HMB level (Experiment 1, P < or = 0.05). Although HMB supplementation did not significantly affect the phagocytic potential of the abdominal macrophages, nitrite levels in the macrophage culture supernatants were higher in 0.01% and 0.05% treatment groups as compared to the controls (Experiment 2, P < or = 0.04; Experiment 3, P < or = 0.05). HMB supplementation did not alter the bird's ability to clear Escherichiacoli or Salmonella arizona from the bloodstream. Beginning 7 days post-hatch, chicks were injected i.v. with a 7% sheep red blood cells suspension. Serum samples were collected to determine the primary and secondary antibody response. Chicks receiving the 0.1% HMB diet in Experiments 1 and 2 exhibited increased IgG and total anti-sheep red blood cell (SRBC) antibody levels during the primary response. During the secondary response, birds consuming the 0.10% HMB diet had elevated IgM levels as well as increased total anti-SRBC levels over the controls in Experiments 1 and 3. These studies show that HMB supplementation improves several immunological functions in young broilers, and such improvement may result in decreased mortality.

Vanadium stimulates immunological responses of chicks.

In a continuation of studies on the interaction of dietary phosphorus (P) and vanadium (V) levels, studies have directed toward an examination of this interaction on the immune system of chicks. Antibody titers to sheep red blood cells (SRBC) were increased at 7 days post-inoculation (PI) by as little as 10 mg V/kg diet in the P-deficient group, while 50 mg V/kg was required in the P-supplemented group. At 14 days PI, only the 50 mg V/kg was significantly higher in both P-deficient and P-supplemented groups. At 21 days PI, vanadium had no significant effect. P-deficiency resulted in a decrease in the percentage of phagocytic macrophages obtained from the abdominal cavity and a decrease in the number of intracytoplasmic SRBC per phagocytic macrophage. These two criteria were increased by vanadium in both the P-deficient and P-supplemented animals. In P-supplemented animals, the CD4/CD8 ratios of lymphocytes obtained from the blood and spleen were increased by the inclusion of 50 mg V/kg diet. The IL-1-like activity of macrophage supernatants was not significantly affected by dietary V, but IL-6 activity was increased. Densitometric analysis of lysates of macrophages isolated from control and V-fed chicks for anti-protein-tyrosinephosphate (PTP) bands indicate that dietary V increased PTP. While the evidence is not clear that there is a P x V interaction in the immune system studies, it is clear that dietary V at the levels used results in a positive immune response of chicks, possibly mediated through increased PTP.

In vitro exposure with beta-hydroxy-beta-methylbutyrate enhances chicken macrophage growth and function.

Beta-hydroxy-beta-methylbutyrate (HMB), a leucine catabolite, has been shown to decrease broiler mortality. One possible target of HMB action may be the cells of the immune system. Macrophages from a chicken macrophage cell line, MQ-NCSU, were exposed to 0, 10, 20, 40, 80, and 100 microg of HMB per 5 x l0(4) cells in a 96-well culture plate. After 24 h of exposure, macrophage proliferation was quantitated by an MTT bioassay. In duplicate experiments, HMB stimulated growth over control (p < or = 0.05) at a wide range of doses. Macrophages were exposed to 20 and 80 microg of HMB and the culture supernatant fractions tested for the presence of nitrite. HMB exposure (20 microg) increased nitrite production by 44.1% over the controls (Experiment 1, p< or =0.035). To determine the phagocytic potential of macrophages after HMB exposure, MQ-NCSU cell line and Sephadex-G50-elicited abdominal macrophages were incubated with fluorescent latex beads (1:40, macrophage to beads ratio) for I h and then analyzed by flow cytometry. When exposed to 40 microg HMB, the phagocytic potential of MQ-NCSU macrophages was significantly higher (31.7%) than that of the controls (p < or = 0.0006). Sephadex-elicited macrophages exhibited 14.4% increased phagocytosis over controls when treated with 80 microg HMB (p < or = 0.0016). When MQ-NCSU macrophages were exposed to HMB, Fc-receptor expression was significantly elevated over the controls (p < or = 0.0001). These data demonstrate that HMB exposure induces proliferation of macrophages in culture as well as enhances macrophage effector functions, such as nitrite production and phagocytosis. The findings of these studies imply that HMB can be used as a possible dietary immunomodulator.

Calcium dependency of interleukin-1 secretion by a chicken macrophage cell line.

The role of calcium in transducing the signal for interleukin-1 (IL-1) secretion was examined in the MQ-NCSU chicken macrophage cell line. Cells were maintained in RPMI 1640 medium supplemented with 5% chicken serum and antibiotic-antimycotic solution at 40 C and 5% CO2. The effects of stimulation with lipopolysaccharide (LPS), calcium ionophore A23187, or a combination of both on IL-1 secretion were examined. Calcium ionophore A23187 did not replace LPS in MQ-NCSU stimulation but the LPS + A23187 combination stimulated more IL-1 than ionophore alone in these cells. The combination of LPS and ionophore did not increase IL-1 secretion above the levels observed with LPS alone. No synergistic effects between LPS and A23187 were evident. In order to demonstrate that IL-1 secretion by the MQ-NCSU cells is a calcium-dependent process, ethylene glycol bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA) was used to chelate free calcium in the cultures. Incorporation of 5 mM EGTA in the cultures lowered IL-1 stimulated by LPS + A23187 to control levels. Addition of 5 mM CaC12 to EGTA-suppressed cultures restored IL-1 secretion. These results indicate that the calcium ionophore, A23187, augments IL-1 secretion by LPS-stimulated MQ-NCSU macrophages and that IL-1 secretion by these cells is a calcium-dependent process.

Transient reduction in gastric acid secretion following gastric mucosal laser irradiation.

This study assessed a novel approach using defocused carbon dioxide (CO2) laser irradiation on the gastric mucosal surface to reduce gastric acid output. Ninety-six Sprague-Dawley rats were randomised to three groups: control, surgical highly selective vagotomy (surgical-HSV), and gastric mucosal irradiation (laser-M). Cysteamine-induced peptic ulceration was studied, including ulcer index (product of the total number of ulcers by the sum of the ulcer length), at 4 weeks and 20 weeks. The mean ulcer index in the surgical-HSV group was significantly reduced compared with controls at 4 weeks and at 20 weeks. The mean ulcer index in the laser-M group was significantly reduced compared with controls at 4 weeks but not at 20 weeks. Histologic analysis did not reveal any mucosal changes in parietal cell mass at 4 weeks and at 20 weeks. The results show a transient antiulcer effect produced by the gastric mucosal irradiation seen at 4 weeks and abolished by 20 weeks. This data supports the feasibility of endoscopic management of peptic ulcer disease.