The emerging role of viruses in the treatment of solid tumours

There is increasing optimism for the use of non-pathogenic viruses in the treatment of many cancers. Initial interest in oncolytic virotherapy was based on the observation of an occasional clinical resolution of a lymphoma after a systemic viral infection. In many cancers, by comparison with normal tissues, the competency of the cellular anti-viral mechanism is impaired, thus creating an exploitable difference between the tumour and normal cells, as an unimpeded viral proliferation in cancer cells is eventually cytocidal. In addition to their oncolytic capability, these particular viruses may be engineered to facilitate gene delivery to tumour cells to produce therapeutic effects such as cytokine secretion and anti -tumour immune responses prior to the eventual cytolysis. There is now promising clinical experience with these viral strategies, particularly as part of multimodal studies, and already several clinical trials are in progress. The limitations of standard cancer chemotherapies, including their lack of specificity with consequent collateral toxicity and the development of cross-resistance, do not appear to apply to viral-based therapies. Furthermore, virotherapy frequently restores chemoradiosensitivity to resistant tumours and has also demonstrated efficacy against cancers that historically have a dismal prognosis. While there is cause for optimism, through continued improvements in the efficiency and safety of systemic delivery, through the emergence of alternative viral agents and through favourable clinical experiences, clinical trials as part of multimodal protocols will be necessary to define clinical utility. Significant progress has been made and this is now a major research area with an increasing annual bibliography.

Effective immunotherapy of weakly immunogenic solid tumours using a combined immunogene therapy and regulatory T-cell inactivation

Obstacles to effective immunotherapeutic anti-cancer approaches include poor immunogenicity of the tumour cells and the presence of tolerogenic mechanisms in the tumour microenvironment. We report an effective immune-based treatment of weakly immunogenic, growing solid tumours using a locally delivered immunogene therapy to promote development of immune effector responses in the tumour microenvironment and a systemic based T regulatory cell (Treg) inactivation strategy to potentiate these responses by elimination of tolerogenic or immune suppressor influences. As the JBS fibrosarcoma is weakly immunogenic and accumulates Treg in its microenvironment with progressive growth, we used this tumour model to test our combined immunotherapies. Plasmids encoding GM-CSF and B7-1 were electrically delivered into 100 mm(3) tumours; Treg inactivation was accomplished by systemic administration of anti-CD25 antibody (Ab). Using this approach, we found that complete elimination of tumours was achieved at a level of 60% by immunogene therapy, 25% for Treg inactivation and 90% for combined therapies. Moreover, we found that these responses were immune transferable, systemic, tumour specific and durable. Combined gene-based immune effector therapy and Treg inactivation represents an effective treatment for weakly antigenic solid growing tumours and that could be considered for clinical development.

Local gene therapy of solid tumors with GM-CSF and B7-1 eradicates both treated and distal tumors

Gene therapy-induced expression of immunostimulatory molecules at tumor cell level may evoke antitumor immune mechanisms by recruiting and enhancing viability of antigen-processing cells and specific tumoricidal lymphocytes. The antitumor efficacy of a plasmid, coding for granulocyte-macrophage colony-stimulating factor (GM-CSF) and the B7-1 costimulatory immune molecule, delivered into growing solid tumors by electroporation was investigated. Murine fibrosarcomas (JBS) growing in Balb/C mice (<or=100 mm3) were transfected with GM-CSF/B7-1-expressing plasmid. Complete tumor regression occurred in greater than 60% of treated animals. This response was systemic, durable and tumor specific, with all responding animals resistant to repeat tumor challenge. Using a liver metastatic model, effective cure of distal metastases was achieved following treatment of the primary subcutaneous tumor. This treatment strategy could be applicable in the clinical setting for effective elimination of both primary tumors and associated metastatic disease.

Role of interleukin (IL-10) in probiotic-mediated immune modulation: an assessment in wild-type and IL-10 knock-out mice

While the impact of Bifidobacterium infantis 35624 and other probiotics on cytokines has been shown in established colitis, the effects of B. infantis consumption in pre-inflammation of interleukin (IL)-10 knock-out (KO) mice and on the wild-type (WT) C57Bl/6 mice have not been well demonstrated. The objective of this study was to examine cytokine responses in mucosal and systemic lymphoid compartments of IL-10 KO mice early in disease and to compare with control WT mice. Mice were fed B. infantis or placebo for 5 weeks and culled prior to the onset of chronic intestinal inflammation (12-14 weeks). The spleen, Peyer's patches and intestinal mucosa were removed and stimulated with various bacterial stimuli. Cytokine levels were measured by enzyme-linked immunosorbent assay. While basal intestinal and systemic cytokine profiles of WT and IL-10 KO mice were similar, transforming growth factor (TGF)-beta was reduced in the spleen of IL-10 KO mice. Following probiotic consumption, interferon (IFN)-gamma was reduced in the Peyer's patch of both WT and IL-10 KO mice. Alterations in IFN-gamma in the Peyer's patches of WT mice (enhancement) versus IL-10 KO (reduction) were observed following in vitro stimulation with salmonella. Differential IL-12p40, CCL2 and CCL5 responses were also observed in IL-10 KO mice and WT mice. The cytokine profile of IL-10 KO mice in early disease was similar to that of WT mice. The most pronounced changes occurred in the Peyer's patch of IL-10 KO mice, suggesting a probiotic mechanism of action independent of IL-10. This study provides a rationale for the use of B. infantis 35624 for the treatment of gastrointestinal inflammation.

Probiotics: an emerging therapy

There is considerable clinical interest in the utility of probiotic therapy--the feeding of (live) non-pathogenic bacteria, originally derived from the alimentary tract, for disease treatment or health promotion. The microflora of the gastrointestinal tract is essential for mucosal protection, for immune education and for metabolism of fecal residue. Physiological disturbances of these processes, when they occur, result from: i) alteration of a microbial ecosystem, originally conserved by evolution; ii) reduced consumption of microorganisms; iii) invasion of pathogens; or iv) modern interventions. Recent data support the use of proven probiotic organisms in prevention and treatment of flora-related gastrointestinal disorders including inflammatory bowel disease, infectious and antibiotic related diarrheas, and post-resection disorders including pouchitis. Therapeutic activity of probiotic bacteria can be due to competition with pathogens for nutrients and mucosal adherence, production of antimicrobial substances, and modulation of mucosal immune functions. Although a promising treatment, controlled clinical trials are necessary to validate the benefit of probiotics.

Lycopene from two food sources does not affect antioxidant or cholesterol status of middle-aged adults

Background

Epidemiological studies have reported associations between reduced cardiovascular disease and diets rich in tomato and/or lycopene. Intervention studies have shown that lycopene-containing foods may reduce cholesterol levels and lipid peroxidation, factors implicated in the initiation of cardiovascular disease. The objective of this study was to determine whether consumption of lycopene rich foods conferred cardiovascular protection to middle-aged adults as indicated by plasma lipid concentrations and measures of ex vivo antioxidants.

Methods

Ten healthy men and women consumed a low lycopene diet with no added lycopene (control treatment) or supplemented with watermelon or tomato juice each containing 20 mg lycopene. Subjects consumed each treatment for three weeks in a crossover design. Plasma, collected weekly was analyzed for total cholesterol, high density lipoprotein cholesterol (HDL-C) and triglyceride concentrations and for the antioxidant biomarkers of malondialdehyde formation products (MDA), plasma glutathione peroxidase (GPX) and ferric reducing ability of plasma (FRAP). Data were analyzed using Proc Mixed Procedure and associations between antioxidant and lipid measures were identified by Pearson's product moment correlation analysis.

Results

Compared to the control diet, the lycopene-containing foods did not affect plasma lipid concentrations or antioxidant biomarkers. Women had higher total cholesterol, HDL-C and triglyceride concentrations than did the men. Total cholesterol was positively correlated to MDA and FRAP while HDL-C was positively correlated to MDA and GPX. GPX was negatively correlated to triglyceride concentration.

Conclusions

The inclusion of watermelon or tomato juice containing 20 mg lycopene did not affect plasma lipid concentrations or antioxidant status of healthy subjects. However, plasma cholesterol levels impacted the results of MDA and FRAP antioxidant tests.

Is the mucosal route of administration essential for probiotic function? Subcutaneous administration is associated with attenuation of murine colitis and arthritis

BACKGROUND

We and others have reported the prophylactic efficacy of oral consumption of probiotic lactobacilli in the interleukin 10 knockout (IL-10 KO) model of colitis. It has not been demonstrated that the oral route is essential for probiotic efficacy.

AIMS

(i) To determine the effect of parenteral administration (subcutaneous) of Lactobacillus salivarius 118 on colitis of IL-10 KO mice; and (ii) to determine if observed responses are disease specific.

METHODS

(i) IL-10 KO mice were injected subcutaneously with L salivarius 118 or saline over 19 weeks. At sacrifice, the bowels were histologically scored. Isolated splenocytes were cultured in vitro and cytokine levels measured. (ii) In the collagen induced arthritis model, DBA/1 mice were injected subcutaneously with the probiotic or saline. At sacrifice, paw thickness was measured and joints were histologically scored.

RESULTS

(i) Colonic inflammatory scores were significantly decreased in IL-10 KO mice injected with L salivarius 118 compared with controls (p<0.05). Proinflammatory cytokine production from stimulated splenocytes was significantly lower for the probiotic group whereas stimulated transforming growth factor beta (TGF-beta) levels were significantly increased (p<0.05). (ii) Scoring of arthritis and paw thickness were significantly improved in the group of mice injected with L salivarius 118 compared with controls.

CONCLUSIONS

(1) Subcutaneous administration of L salivarius 118 significantly attenuated colitis in the IL-10 KO model and suppressed collagen induced arthritis, suggesting that the oral route may not be essential for probiotic anti-inflammatory effects and that responses are not disease specific. (2) The probiotic effect was associated with reduced production of proinflammatory (T helper 1) cytokines and maintained production of anti-TGF-beta.

Oral immune tolerance to tumor specific antigens may confer growth advantage to esophageal and gastric cancers

Oral administration of antigens induces antigen-specific systemic immune tolerance (Oral Tolerance). We postulate that the poorer prognosis of foregut cancers might, in part be explained by the systemic immune tolerizing effect of tumor specific antigens shed into and processed by the gut immune system thus conferring a growth advantage specific to individual cancers. Immunocompetent Balb/c mice were fed by gavage, either tumor tissue (JBS/CarB) in phosphate buffered saline (PBS) or PBS alone, daily for 14 days. On day 15 either subcutaneous tumors were induced or animals were immunized with cells in adjuvant. JBS tumors appeared earlier and grew faster in the JBS tumor fed mice than in either the PBS (P = 0.025) or CarB (P = 0.168) fed animals. The delayed type hypersensitivity response in tolerized mice was significantly abrogated (P < 0.01) compared to controls. These experiments demonstrate antigen specific oral immune tolerance for tumors, which is reflected in a faster growth rate and impaired delayed type hypersensitivity response. Similar mechanisms may be operational in human esophagogastric malignancy and may in part explain their poorer outcome.

Culicoides mohave (Diptera: Ceratopogonidae): new occurrence records and potential role in transmission of hemorrhagic disease

Biting midges of the genus Culicoides are important in the transmission of viral diseases affecting wild and domestic ungulates, including bluetongue (BLU) and epizootic hemorrhagic disease (EHD). The primary known vector for these viruses is C. sonorensis Wirth & Jones, however, it has been speculated that other species of Culicoides may also be involved. One potential candidate is C. mohave, a poorly studied species found in inland desert areas of the southwestern United States. In 2000 and 2001, we collected C. mohave and C. sonorensis at six sites in a previously unsurveyed area in the Sonoran Desert of southwestern Arizona and used PCR to detect nucleic acids associated with BLU and EHD viruses. C. mohave was abundant at two low-elevation sites on the study area, but uncommon or absent elsewhere. C. sonorensis commonly occurred along with C. mohave at one site, but was much less abundant. All C. mohave pools were negative for BLU viral RNA, however, 35% yielded positive results for EHD. All C. sonorensis were negative for both BLU and EHD. Our results suggest that C. mohave is a potential vector of EHD virus in this area, however additional studies are needed to determine its ability to transmit EHD.

Double blind, placebo controlled trial of two probiotic strains in interleukin 10 knockout mice and mechanistic link with cytokine balance

BACKGROUND

Prophylactic efficacy against colitis following lactobacillus consumption in interleukin 10 (IL-10) knockout (KO) mice has been reported. Whether this applies equally to other probiotic strains is unknown, and the mechanism is unclear.

AIMS

(1) To compare the effect of feeding Lactobacillus salivarius subspecies salivarius 433118 and Bifidobacterium infantis 35624 against placebo on enterocolitis, the intestinal microflora, and (2) to compare the systemic immunological response to in vitro microbial challenge in probiotic fed and control IL-10 KO mice.

METHODS

Three groups of 10 IL-10 KO mice were fed fermented milk products containing Lb salivarius 433118 at 10(9) CFU/ml, B infantis 35624 at 10(8) CFU/ml, and unmodified milk, respectively, for 19 weeks. Faecal samples were taken at regular intervals to confirm gut transit, recovery of fed probiotics, and to assess the impact on the microflora. At sacrifice, the bowels were histologically scored. Cytokine production from Peyers' patches and splenocytes was measured in vitro by ELISA.

RESULTS

Faecal recovery of probiotics was confirmed in all probiotic fed mice but not in controls. Colonic and caecal inflammatory scores were significantly decreased in both groups of probiotic fed mice (p<0.05). Proinflammatory cytokine production by Peyers' patches and splenocytes was significantly reduced in probiotic fed animals whereas transforming growth factor beta (TGF-beta) levels were maintained.

CONCLUSION

Both Lactobacillus salivarius 433118 and Bifidobacterium infantis 35624 significantly attenuate colitis in this murine model. Attenuation of colitis is associated with a reduced ability to produce Th1-type cytokines systemically and mucosally, while levels of TGF-beta are maintained.

Occurrence of infectious upper respiratory tract disease and response to vaccination in horses on six sentinel premises in northern Colorado

REASONS FOR PERFORMING STUDY

Horses vaccinated against common agents of infectious upper respiratory disease (IURD) may not have detectable serum antibody and may not be protected from clinical disease.

OBJECTIVES

The objectives of this study were to 1) investigate the serological response of horses to vaccination against influenza virus (H3N8 and H7N7) and equine herpesviruses (EHV) in a field setting and 2) evaluate associations among vaccination status, serum antibody concentrations, and occurrences of IURD in monitored horses.

METHODS

In this study, horses on 6 Colorado premises were vaccinated parenterally against influenza virus and EHV, and serological response evaluated. Horses were monitored, and biological samples collected from individuals with clinical IURD and control horses.

RESULTS

Of 173 horses, 61 (35.3%), 21 (12.1%) and 4 (2.3%) seroconverted in response to vaccination against EHV, influenza virus H7N7 and influenza virus H3N8, respectively.

CONCLUSIONS

Outbreaks of IURD in study horses were associated with influenza virus H3N8 and Streptococcus equi infection, and serological response to vaccination with conventional products was poor.

POTENTIAL RELEVANCE

These results confirm that horses may not respond with detectable serological responses to conventional vaccination against common respiratory viruses and, therefore, suggest that alternate methods of protecting horses against common respiratory viruses should be sought.

PCR detection of Mycobacterium paratuberculosis in Crohn's disease granulomas isolated by laser capture microdissection

BACKGROUND AND AIMS

The uncertainty surrounding the role of Mycobacterium avium subsp paratuberculosis (Map) in Crohn's disease has been compounded by possible contamination from Map present in the lumen microflora. This study used laser capture microdissection (LCM) and polymerase chain reaction (PCR) to detect Map DNA in subepithelial granulomas, isolated from 15 surgically resected, formalin fixed specimens of granulomatous Crohn's disease and from 12 granulomatous disease controls (10 bowel, 2 non-bowel).

METHODS

The effect of amplicon size on reliability of PCR from formalin fixed samples was examined by amplifying 435 bp and 133 bp sequences of the human APC gene. After this, nested primers were designed to detect a small fragment (155 bp) of the Map specific IS900 gene in Crohn's granulomas. LCM isolated granulomas from Map culture positive bovine intestine was used as positive control. PCR product specificity was confirmed by direct DNA sequencing.

RESULTS

The smaller, but not the larger, fragment of the APC gene amplified reliably in all samples. Amplification of the 155 bp fragment of the IS900 gene detected Map DNA in microdissected Crohn's granulomas in 6 of 15 cases, and in 0 of 12 disease control granulomas.

CONCLUSIONS

LCM can be used to detect Map DNA in granulomas in a proportion of patients with Crohn's disease. However, formalin fixation requires that comparatively short DNA fragments of the Map specific IS900 gene be targeted, to permit consistent detection. Detection of Map DNA within granulomas might suggest an infectious aetiology in a subset of patients; alternatively, a transmissible agent may not be involved but mycobacterial DNA may influence pathogenesis by modifying the local cytokine responses.

Quality control Lactobacillus strains for use with the API 50CH and API ZYM systems at 37 degrees C

The API 50CH and API ZYM systems fulfil an important role in the polyphasic taxonomic identification of lactobacilli. When the API 50CH fermentation profile of the quality control Lactobacillus casei var. alactosus (Lb. paracasei subsp. paracasei) strain NCFB 206 was determined at 37 degrees C, it was found to differ from that determined at 30 degrees C by BioMéreiux SA (Montalieu Vercieu, France) and the National Collection of Food Bacteria (Aberdeen, Scotland). In addition, the API 50CH fermentation and API ZYM profiles of Lb. casei strain ATCC 334T determined at 37 degrees C differed from those determined at 30 degrees C by Lee and Simard (1984). Strains NCFB 206 and ATCC 334T were thus assumed to exhibit temperature-dependent variation in fermentation profile, a phenomenon recently described by Nigatu et al. (2000). In contrast, Lb. rhamnosus strain ATCC 243T did not exhibit temperature-dependent variation in fermentation profile. Moreover, the fermentation profile obtained at 37 degrees C differed in only one respect (positive beta-gentiobiose utilisation) from that published by Collins et al. (1989). In addition, Lactobacillus strain GG produced a stable and reproducible API ZYM profile at 37 degrees C, although some variation in the level of enzyme activity was evident. Thus, strain NCFB 206 was replaced by strain ATCC 243T as the quality control strain of choice for use with the API 50CH fermentation system, and Lactobacillus strain GG adopted for use as a quality control strain with the API ZYM system for strain identification of lactobacilli at 37 degrees C. The API 50CH and API ZYM profiles of the commercially important Lactobacillus strains NCFB 1748, GG, KLD, F19, and ACA-DC 212.3 were determined at 37 degrees C after anaerobic growth in MRS broth. The fermentation and enzyme profiles of strain NCFB 1748 were almost identical to those of Lb. crispatus ATCC 33820T, those of strain GG were found to be more similar to those of Lb. rhamnosus strain 243T than Lb. zeae strain ATCC 15820T, those of strain KLD were most similar to those of Lb. fermentum DSM 20052T, while those of strains F19 and ACA-DC 212.3 were similar to those of Lb. casei strain ATCC 334T.

Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis

PURPOSE

Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches.

METHODS

After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed.

RESULTS

Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated.

CONCLUSIONS

Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are specific to ulcerative colitis pouches, they may play a role in the pathogenesis of pouchitis.

Tissue viral load variability in chronic hepatitis C

OBJECTIVE

Liver biopsy is regarded as the gold standard for assessing disease activity in chronic hepatitis C, but sampling error is a potential limitation. Whether sampling variability applies equally to viral load assessment as it does to histology is uncertain. To examine this, we compared viral load between right- and left-lobe biopsy specimens from patients infected with hepatitis C virus (HCV).

METHODS

Bilobe biopsies were taken from 16 patients who were serum positive for HCV RNA by reverse transcription-polymerase chain reaction. Genotype was identified by reverse line probe hybridization. There was an absence of competing risk factors for infectious and other liver diseases in this patient group. Histology and hepatic viral load were assessed blindly. None of the patients had received antiviral therapy at the time of study.

RESULTS

Detection of HCV in right and left lobes was concordant with serum positivity in all cases. The viral load between lobes was highly correlated (p = 0.0003, r = 0.79). In contrast, the histological activity indices of inflammation and fibrosis/cirrhosis were poorly correlated between lobes (p = 0.038, r = 0.60, and p = 0.098, r = 0.50, respectively).

CONCLUSION

Hepatic viral load variability does not suffer from the same degree of heterogeneity of sampling variability as does histology.

Gradient diffusion antibiotic susceptibility testing of potentially probiotic lactobacilli

Minimum inhibitory contentrations (MICs) of selected inhibitors of cell wall synthesis (benzylpenicillin, ampicillin, and vancomycin), protein synthesis (gentamicin, streptomycin, tetracycline, chloramphenicol, and erythromycin), and nucleic acid synthesis (co-trimoxazole, rifampicin, and metronidazole) were determined by gradient diffusion (E test; AB Biodisk, Solna, Sweden) on deMan, Rogosa, Sharpe (MRS) agar for Lactobacillus strain GG and 11 closely related, rapidly growing, facultatively anaerobic, potentially probiotic Lactobacillus rhamnosus strains. All strains were resistant to vancomycin (MIC90 > or = 256 microg/ml), co-trimoxazole (MIC90 > or = 32 microg/ml), metronidazole (MIC90 > or = 32 microg/ml), gentamicin (MIC90 > or = 128 microg/ml), and streptomycin (MIC90 > or = 256 microg/ml), and sensitive to pencillin G (MIC90 > 0.375 microg/ml), ampicillin (MIC90 > 0.750 microg/ml), rifampicin (MIC90 > 0.375 microg/ml), tetracycline (MIC90 > 1.5 microg/ml), chloramphenicol (MIC90 > 8 microg/ml), and erythromycin (MIC90 > 2 microg/ml). E test MICs were also determined for L. acidophilus National Collection of Food Bacteria (NCFB) 1748 and L. reuteri Deutsche Sammlung von Mikroorganismen 20016T by the inoculum application method recommended by the manufacturer (swabbing), with and without antibiotic prediffusion for 1 h at room temperature, and by an alternative inoculum application (agar overlay) method, without antibiotic prediffusion. Antibiotic prediffusion increased the MICs for penicillin G, ampicillin, tetracycline, and chloramphenicol by up to 2 log2 MIC dilutions without changing antibiotic susceptibility category. Agar overlay application also increased the MICs for these antibiotics as well as for gentamicin by up to 3 log2 MIC dilutions without changing antibiotic susceptibility category. Exact agreement between MICs determined by swab and agar overlay application without antibiotic prediffusion was strain dependent: 54.5% for strain DSM 20016T and 72.7% for strain NCFB 1748. The swab and agar overlay gradient diffusion methods provide a reliable basis for antibiotic susceptibility testing of rapidly growing, facultatively anaerobic lactobacilli, using MRS agar as test medium and are readily applicable for testing individual isolates as needed.

Fas ligand upregulation is an early event in colonic carcinogenesis

BACKGROUND/AIMS

Fas ligand (FasL) is a mediator of apoptosis via the Fas receptor (Fas/CD95/APO-1). Normal colonic epithelium expresses Fas, and appears to be relatively sensitive to Fas mediated apoptosis. Colonic adenocarcinomas coexpress FasL and Fas without undergoing widespread apoptosis. This study investigates the expression of FasL in colonic carcinogenesis from the earliest stages of the adenoma-carcinoma sequence.

METHODS

FasL expression was determined in colonic adenomas (n = 38) of varying degrees of dysplasia and histological type by immunohistochemistry. Adenomas that contained areas of carcinomatous change were included (n = 12 of 38). Normal colonic epithelium (n = 10), hyperplastic polyps (n = 8), and serrated adenomas (n = 3) from patients without colonic adenocarcinomas were used for comparison. Cell death was detected in situ in adenomas using TUNEL (terminal transferase mediated dUTP nick end labelling).

RESULTS

In normal colonic epithelium and hyperplastic polyps, FasL expression was restricted to the luminal surface of the crypts, where Fas-FasL coexpression was coincident with a high frequency of TUNEL positive epithelial cells. All adenomas (n = 38) had an altered distribution of positive FasL staining; FasL expression was found in most cells (> 70% of neoplastic cells). Expression of Fas was also detected throughout the adenomas, but coexpression of FasL and Fas was not associated with TUNEL positivity in most cells.

CONCLUSIONS

FasL upregulation occurs early in the adenoma-carcinoma sequence of colon carcinogenesis, and is evident at the level of mild dysplasia. The lack of pronounced apoptosis in areas of adenomas coexpressing Fas and FasL suggests that colonocytes acquire resistance to Fas mediated apoptosis early in the transformation process.

Probiotic impact on microbial flora, inflammation and tumour development in IL-10 knockout mice

BACKGROUND

The enteric bacterial flora has been implicated in the pathogenesis of enterocolitis and colon cancer in C57BL/6 IL-10 knockout mice. Probiotic Lactobacilli modify the enteric flora and are thought to have a beneficial effect on enterocolitis. We conducted a controlled feeding trial in IL-10 knockout mice using the probiotic Lactobacillus salivarius ssp. salivarius UCC118.

AIM

To determine the effect of probiotic consumption on the gastrointestinal microflora, tumour development and colitis in IL-10 knockout mice.

METHODS

Twenty IL-10 knockout mice were studied (10 consumed probiotic organisms in milk and 10 consumed unmodified milk) for 16 weeks. Faecal microbial analysis was performed weekly to enumerate excretion of the probiotic UCC118, total lactobacilli, Clostridium perfringens, bacteroides, coliforms, bifidobacteria and enterococci. At sacrifice, the small and large bowel were microbiologically and histologically assessed.

RESULTS

L. salivarius UCC118 was detected in faeces from all mice in the probiotic fed group, but not the control group. Faecal coliform and enterococci levels were significantly reduced in probiotic fed animals compared to the controls (P < 0.05). At sacrifice, a significant reduction in C. perfringens numbers was observed in the test mice (P < 0.05). There were no fatalities in the test group compared to two deaths from fulminant colitis in the control group. Only one test mouse developed colonic adenocarcinoma compared to five in the control group. Test animal mucosal inflammation consistently scored lower than that of the control mice.

CONCLUSION

In this placebo controlled trial, modification of enteric flora in IL-10 knockout mice by probiotic lactobacilli was associated with reduced prevalence of colon cancer and mucosal inflammatory activity.

Constitutive ERK1/2 activation in esophagogastric rib bone marrow micrometastatic cells is MEK-independent

In this study, we examined the mitogen-activated protein kinase (MAPK) cascade in micrometastatic cell lines generated from rib bone marrow (RBM) of patients undergoing resection of esophagogastric malignancies. The molecular mechanism(s) involved in esophagogastric MAPK activation have not previously been investigated. Constitutive activation of both ERK1 and -2 isoforms was evident in each of the five RBM cell lines. Elk-1, a transcription factor activated by the ERK1/2 pathway was also found to be constitutively activated. Cell lines generated from metastases of involved lymph nodes (OC2) and ascites (OC1) of patients with esophageal cancer do not display, however, hyperphosphorylation of ERK1/2. Constitutive RBM ERK1/2 activation is protein kinase C and phosphatidylinositol 3-kinase dependent. Surprisingly, constitutive ERK1/2 activation is MEK-independent. Pharmacological inhibition of MEK with two specific inhibitors, PD 98059 and U0126, were both ineffective in blocking ERK activation. Similarly, the use of a dominant negative MEK mutant was without effect. Interestingly, experiments overexpressing two different dominant negative Pak1 mutants significantly reduced RBM ERK1/2 activation, albeit not to the same extent for all cell lines. We also examined the role of three different phosphatases, PAC1, MKP-1, and -2. While RBM ERK1/2 activation was found to be PAC1- and MKP-2-independent, surprisingly, MKP-1 was down-regulated in all five RBM cell lines. In conclusion, we provide evidence for the first time for a MEK-independent constitutive ERK1/2 activation pathway in esophagogastric RBM cell lines. These findings have important implications for drug treatment strategies which currently target MEK in other forms of cancer.

Serologic evaluation, efficacy, and safety of a commerical modified-live canine distemper vaccine in domestic ferrets

OBJECTIVE

To determine efficacy and safety of a commercial modified-live canine distemper virus (CDV) vaccine used for prophylaxis in domestic ferrets.

ANIMALS

Sixteen 16-week-old neutered male ferrets.

PROCEDURES

Equal groups of ferrets were inoculated subcutaneously at 16 and 20 weeks of age with saline (0.9% NaCl) solution or a vaccine derived from the Onderstepoort CDV strain and attenuated in a primate cell line. Live virulent CDV was administered to all ferrets intranasally and orally 3 weeks after the second inoculation. Clinical signs and body weights were monitored regularly during the study. Blood samples for serologic examination were drawn prior to each inoculation, before challenge exposure, and 10, 15, and 21 days after exposure. Blood samples for reverse transcriptase polymerase chain reaction (RT-PCR) were obtained 5 days after the first vaccination, and 5, 10, 15, and 21 days after challenge exposure.

RESULTS

After challenge exposure, control ferrets had significantly more clinical signs and weight loss, compared with vaccinates. All vaccinated ferrets survived, whereas all control ferrets died. The RT-PCR assay was successful in detecting CDV in blood and fresh or formalin-fixed tissues from infected ferrets.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggest that the vaccine when given SC to domestic ferrets as directed is safe and protective against challenge exposure with virulent CDV. The RT-PCR assay may simplify detection of CDV in fresh and fixed tissues.

Inferred hepatitis C virus quasispecies diversity is influenced by choice of DNA polymerase in reverse transcriptase-polymerase chain reactions

The hepatitis C virus (HCV) is known to circulate in vivo as a quasispecies, a population of closely related, but genetically nonidentical virions. HCV reverse transcriptase (RT)-(nested) polymerase chain reaction (PCR) strategies are used to study quasispecies diversity at certain important viral genetic loci, predominantly at hypervariable region 1 (HVR 1) of the E2 envelope gene, and the interferon sensitivity determining region (ISDR) of the nonstructural 5a (NS5a) gene. We have found that the choice of DNA polymerase employed in viral PCR has effects on the inferred viral diversity at two distinct loci on the HCV genome. Nested HVR 1 and ISDR PCR was performed with both proofreading (Pwo) and nonproofreading (Taq) DNA polymerases on identical cDNA derived from three separate HCV-positive sera. Amplicons were cloned and sequences determined for 18-20 individual clones per sample. Quasispecies diversity determined from HVR 1 and ISDR PCR products showed that there was a marked effect on the inferred diversity depending on which DNA polymerase was employed in the PCR. The deduced amino acid sequences of the major variants within each specimen were identical for both Taq and Pwo DNA polymerase-mediated PCRs. However, a greater number of minor variants were observed in the Taq-generated amplicons, 80% of which were not observed in the Pwo-generated amplicons. Primer editing in the Pwo-generated amplicons was observed in 19% (20/104) of clones examined. Single-strand conformational polymorphism analysis of multiple replicates of each amplicon revealed good intra-PCR reproducibility in terms of genetic heterogeneity, and that as such the observations were not due to poor PCR reproducibility. The use of nonproofreading DNA polymerases to assess viral diversity can yield an incorrect quasispecies spectrum and affect RT-PCR assay performance. The contribution of Taq-induced errors and lack of adaptability of primers to potentially heterologous template-binding sites indicate that proofreading DNA polymerases should be the enzyme of choice in these systems.

In vitro selection criteria for probiotic bacteria of human origin: correlation with in vivo findings

The enteric flora comprises approximately 95% of the total number of cells in the human body and can elicit immune responses while protecting against microbial pathogens. However, the resident bacterial flora of the gastrointestinal tract may also be implicated in the pathogenesis of diseases such as inflammatory bowel disease (ulcerative colitis and Crohn disease). The objectives of the Probiotic Research Group based at University College Cork were to isolate and identify lactic acid bacteria exhibiting beneficial probiotic traits, such as bile tolerance in the absence of deconjugation activity, acid resistance, adherence to host epithelial tissue, and in vitro antagonism of pathogenic microorganisms or those suspected of promoting inflammation. To isolate potentially effective probiotic bacteria, we screened the microbial population adhering to surgically resected segments of the gastrointestinal tract (the environment in which they may subsequently be reintroduced and required to function). In total, 1500 bacterial strains from resected human terminal ilea were assessed. From among these organisms, Lactobacillus salivarius subsp. salivarius strain UCC118 was selected for further study. In mouse feeding trials, milk-borne L. salivarius strain UCC118 could successfully colonize the murine gastrointestinal tract. A human feeding study conducted in 80 healthy volunteers showed that yogurt can be used as a vehicle for delivery of strain UCC118 to the human gastrointestinal tract with considerable efficacy in influencing gut flora and colonization. In summary, we developed criteria for in vitro selection of probiotic bacteria that may reflect certain in vivo effects on the host such as modulation of gastrointestinal tract microflora.

Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy

The viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration of various proportions of viable to heat-killed bacteria was then compared with conventional plating on nutrient agar. Direct microscopic enumeration of bacteria indicated that plate counting led to an underestimation of bacterial numbers, which was most likely related to clumping. Similarly, LIVE/DEAD BacLight staining yielded bacterial counts that were higher than cell numbers obtained by plate counting (CFU) in milk and fermented milk. These results indicate the value of the microscopic approach for rapid viability testing of such probiotic products. In contrast, the numbers obtained by direct microscopic counting for Cheddar cheese and spray-dried probiotic milk powder were lower than those obtained by plate counting. These results highlight the limitations of LIVE/DEAD BacLight staining and the need to optimize the technique for different strain-product combinations. The minimum detection limit for in situ viability staining in conjunction with confocal scanning laser microscopy enumeration was approximately 10(8) bacteria/ml (equivalent to approximately 10(7) CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.

Interferon-gamma sensitizes colonic epithelial cell lines to physiological and therapeutic inducers of colonocyte apoptosis

Homeostasis in the colonic epithelium is achieved by a continuous cycle of proliferation and apoptosis, in which imbalances are associated with disease. Inflammatory bowel disease (IBD) and colon cancer are associated with either excessive or insufficient apoptosis of colonic epithelial cells, respectively. By using two colonic epithelial cell lines, HT29 and SW620, we investigated how the epithelial cell's sensitivity to apoptosis was regulated by the proinflammatory cytokine interferon-gamma (IFN-gamma). We found that IFN-gamma sensitized HT29 cells, and to a lesser extent SW620, to diverse inducers of apoptosis of physiologic or therapeutic relevance to the colon. These apoptosis inducers included Fas (CD95/APO-1) ligand (FasL), short-chain fatty acids, and chemotherapeutic drugs. The extent of IFN-gamma-mediated apoptosis sensitization in these two cell lines correlated well with the degree of IFN-gamma-mediated upregulation of the proapoptotic protease caspase-1. Although IFN-gamma alone effectively sensitized HT29 cells to apoptosis, inclusion of the protein synthesis inhibitor cyclohexamide (CHX) during apoptotic challenge was necessary for maximal sensitization of SW620. The requirement of CHX to sensitize SW620 cells to apoptosis implies a need to inhibit translation of antiapoptotic proteins absent from HT29. In particular, the antiapoptotic protein Bcl-2 was strongly expressed in SW620 cells but absent from HT29. Our results indicate that IFN-gamma increases the sensitivity of colonic epithelial cells to diverse apoptotic stimuli in concert, via upregulation of caspase-1. Our findings implicate caspase-1 and Bcl-2 as important central points of control determining the general sensitivity of colonic epithelial cells to apoptosis.

Interferon-gamma sensitizes colonic epithelial cell lines to physiological and therapeutic inducers of colonocyte apoptosis

Homeostasis in the colonic epithelium is achieved by a continuous cycle of proliferation and apoptosis, in which imbalances are associated with disease. Inflammatory bowel disease (IBD) and colon cancer are associated with either excessive or insufficient apoptosis of colonic epithelial cells, respectively. By using two colonic epithelial cell lines, HT29 and SW620, we investigated how the epithelial cell's sensitivity to apoptosis was regulated by the proinflammatory cytokine interferon-gamma (IFN-gamma). We found that IFN-gamma sensitized HT29 cells, and to a lesser extent SW620, to diverse inducers of apoptosis of physiologic or therapeutic relevance to the colon. These apoptosis inducers included Fas (CD95/APO-1) ligand (FasL), short-chain fatty acids, and chemotherapeutic drugs. The extent of IFN-gamma-mediated apoptosis sensitization in these two cell lines correlated well with the degree of IFN-gamma-mediated upregulation of the proapoptotic protease caspase-1. Although IFN-gamma alone effectively sensitized HT29 cells to apoptosis, inclusion of the protein synthesis inhibitor cyclohexamide (CHX) during apoptotic challenge was necessary for maximal sensitization of SW620. The requirement of CHX to sensitize SW620 cells to apoptosis implies a need to inhibit translation of antiapoptotic proteins absent from HT29. In particular, the antiapoptotic protein Bcl-2 was strongly expressed in SW620 cells but absent from HT29. Our results indicate that IFN-gamma increases the sensitivity of colonic epithelial cells to diverse apoptotic stimuli in concert, via upregulation of caspase-1. Our findings implicate caspase-1 and Bcl-2 as important central points of control determining the general sensitivity of colonic epithelial cells to apoptosis.

The inflammatory response within Dukes' B colorectal cancers: implications for progression of micrometastases and patient survival

OBJECTIVES

The aim of this study was to determine the relationship between the inflammatory response in primary colorectal carcinomas, patient outcome, and the fate of bone marrow micrometastases.

METHODS

The populations studied were a) 155 consecutive patients with Dukes' B colorectal cancer and follow-up for a mean of 5 yr, from the Mercy Hospital, Cork, and b) 260 consecutive patients with rectal carcinoma Dukes' B and follow-up for >10 yr, from St. Mark's Hospital, London. The primary tumor was assessed for the Jass and "Crohn's-like" lymphoid reactions. In 36 consecutive patients, bone marrow aspirates were examined for micrometastases before and > or = 6 months postoperatively.

RESULTS

The relationship between prognosis and the inflammatory reactivity in the tumors was similar in both populations. In the Mercy group there were two deaths among 40 patients who had coexistent Jass and Crohn's-like infiltrates. This contrasted with 25 deaths among 58 patients in whom both infiltrates were absent (p < 0.005). Results were intermediate in cases in which either type of inflammatory reaction was present alone. In the St. Mark' s patients similar prognostic differences were sustained for up to 10 yr. Bone marrow micrometastases were present in 12/36 patients preoperatively and in 14/36 postoperatively. Seven of 12 patients with preoperative micrometastases were negative postoperatively, indicating clearance of tumor cells. Nine of 24 who tested negative preoperatively had micrometastases postoperatively. The clearance and presence of postoperative micrometastases was related to the immunological responses in the primary tumor.

CONCLUSIONS

These results demonstrate an association between the inflammatory reaction, prognosis, and clearance of micrometastases, indicating a systemic antitumor reaction that confers a survival advantage.

Epizootic malignant catarrhal fever in three bison herds: differences from cattle and association with ovine herpesvirus-2

Three bison herds in Colorado experienced high mortality from malignant catarrhal fever (MCF). In comparison with cattle, the bison had a more rapidly progressive disease, fewer clinical signs, and milder inflammatory histologic lesions. There was consistent association with ovine herpesvirus-2 (OHV-2). Contact with sheep was not consistent. Of 17 animals in herd A, 15 died of acute MCF; 1 was slaughtered while healthy; and 1 developed clinical signs of MCF, was treated with corticosteroids and antibiotics, and died of fungal abomasitis and rhinitis after 5 months. In herds B and C, approximately 300 of 900 and 18 of 20 died of MCF following brief clinical disease. The nearest sheep were 1 mile away from herd A, but direct contact with sheep could be documented in herds B and C. Complete gross and histologic examinations were conducted on 34 animals, including all animals in herd A, and MCF was diagnosed in 31. In addition, field necropsies were performed on all dead animals in herd B and most in herd C and MCF was diagnosed on the basis of the gross lesions in most animals. Clinical signs of each animal in herd A were recorded. Illness was brief, usually 8-48 hours. Clinical signs were subtle; separation from the herd was often observed. In all 3 herds, hemorrhagic cystitis and multifocal ulceration of the alimentary tract were consistently found at necropsy. Mild lymphocytic vasculitis was present in multiple organs. Ovine herpesvirus-2 was found by polymerase chain reaction (PCR) in 71 of 105 formalin-fixed tissue specimens from 29 of 31 animals with MCF. In herd A, blood samples from 13 animals were collected at 5 time points and tested by PCR for the presence of OHV-2 viral sequences in peripheral blood leukocytes. Nine bison with a positive PCR test and 4 with negative results prior to clinical illness died of MCF.

Bovine viral diarrhea virus in New World camelids

A virus known to cause multiple problems in cattle, bovine viral diarrhea virus, was isolated from 3 different cases in New World camelids. Virus isolation, immunoperoxidase staining, and fluorescent antibody staining were used to detect the virus. The herds involved were screened for antibody titers to bovine viral diarrhea and virus isolation from the buffy coat. Bovine viral diarrhea virus should be considered as a cause of death in young and old New World camelids.

Effect of conjugated bile salts on antibiotic susceptibility of bile salt-tolerant Lactobacillus and Bifidobacterium isolates

Virtually every antibiotic may cause in vivo alterations in the number, level, and composition of the indigenous microbiotae. The degree to which the microbiotae are disturbed depends on many factors. Although bile may augment antibiotic activity, studies on the effect of bile on the antibiotic susceptibility of indigenous and exogenous probiotic microorganisms are lacking. It was against this background that the antibiotic susceptibility of 37 bile salt-tolerant Lactobacillus and 11 Bifidobacterium isolates from human and other sources was determined in the presence of 0.5% wt/wt oxgall (conjugated bile salts). Oxgall did not affect the intrinsic resistance of lactobacilli to metronidazole (5 microg), vancomycin (30 microg), and cotrimoxazole (25 microg), whereas it resulted in a complete loss of resistance to polymyxin B (300 microg) and the aminoglycosides gentamicin (10 microg), kanamycin (30 microg), and streptomycin (10 microg) for most strains studied (P < 0.001). Oxgall did not affect the intrinsic resistance of bifidobacteria to metronidazole and vancomycin, whereas polymyxin B and co-trimoxazole resistance was diminished (P < 0.05) and aminoglycoside resistance was lost (P < 0.001). Seven lactobacilli, but no bifidobacteria strain, showed unaltered intrinsic antibiotic resistance profiles in the presence of oxgall. Oxgall affected the extrinsic susceptibility of lactobacilli and bifidobacteria to penicillin G (10 microg), ampicillin (10 microg), tetracycline (30 microg), chloramphenicol (30 microg), erythromycin (15 microg), and rifampicin (5 microg) in a source- and strain-dependent manner. Human strain-drug combinations of lactobacilli (P < 0.05) and bifidobacteria (P < 0.01) were more likely to show no change or decreased susceptibility compared with other strain-drug combinations. The antimicrobial activity spectra of polymyxin B and the aminoglycosides should not be considered limited to gram-negative bacteria but extended to include gram-positive genera of the indigenous and transiting microbiotae in the presence of conjugated bile salts. Those lactobacilli (7 of 37) that show unaltered intrinsic and diminished extrinsic antibiotic susceptibility in the presence of oxgall may possess greater upper gastrointestinal tract transit tolerance in the presence of antibiotics.

Malignant catarrhal fever: polymerase chain reaction survey for ovine herpesvirus 2 and other persistent herpesvirus and retrovirus infections of dairy cattle and bison

Using a polymerase chain reaction (PCR) test for sequences of ovine herpesvirus 2 (OHV2), this virus was shown to be significantly associated with sheep-associated malignant catarrhal fever (SA-MCF) in terminal cases of disease in 34 cattle and 53 bison. Ovine herpesvirus 2 was not detected in cattle (38) and bison (10) that succumbed to other diseases. Other persistent herpesviruses, retroviruses, and pestivirus, some of which have been previously isolated from cases of SA-MCF, were not associated with the disease. These included bovine herpesvirus 4 (BHV4), bovine lymphotrophic herpesvirus (BLHV), bovine syncytial virus (BSV, also known as bovine spumavirus), bovine immunodeficiency virus (BIV), and bovine viral diarrhea virus (BVDV). A PCR survey for OHV2 in DNA from individual cow's peripheral blood lymphocytes in 4 dairies showed that the 1 dairy that was in close contact to sheep had a prevalence of OHV2 of 21.3%, whereas the 3 other dairies had no OHV2. Prevalence of the other herpesviruses and retroviruses in the dairy cows was variable, ranging from 2% to 51% for BHV4, 52% to 78.7% for BLHV, and 10% to 34% for BSV. Bovine lymphotrophic herpesvirus and BSV were also found in a few (1-4 of 21 tested) cases of terminal SA-MCF, but BIV and BVDV were not found in either the dairy cows sampled, or in the cases of SA-MCE No significant correlation was found between the presence of any 2 viruses (OHV2, BHV4, BLHV, BSV) in the dairy cows or terminal cases of SA-MCE

Neurokinin-1 receptor expression in inflammatory bowel disease: molecular quantitation and localisation

BACKGROUND

Substantial evidence implicates the neuropeptide substance P (SP) in mucosal immunoinflammatory responses. Autoradiographic studies have suggested a disturbance in SP receptor expression in inflammatory bowel disease (IBD).

AIMS

Because of technical limitations such as poor cellular resolution with autoradiography, we used molecular methods to specifically localise the cellular expression of the neurokinin-1 receptor (NK-1R) in IBD colon, and to quantitate NK-1R mRNA expression levels therein.

METHODS

In situ hybridisation and immunohistochemistry were used to localise NK-1R mRNA and protein, respectively, in normal, ulcerative colitis (UC), and Crohn's disease (CD) colonic resections. NK-1R mRNA expression levels of normal, UC, and CD mucosal biopsies were quantitated by competitive reverse transcription-polymerase chain reaction.

RESULTS

NK-1R expression was localised to lamina propria mononuclear cells, epithelium, submucosal vasculature, smooth muscle, and myenteric plexus of normal and IBD colon. No ectopic NK-1R expression was observed in IBD. However, we found increased numbers of NK-1R expressing lymphoid cells in IBD tissue, aberrant negative epithelial expression of NK-1R in UC, and increased expression of NK-1R in CD myenteric plexus. Quantitation of NK-1R mRNA expression in IBD colonic mucosal biopsies revealed marked upregulation of NK-1R mRNA levels compared with non-inflamed mucosal expression levels (p<0.01).

CONCLUSIONS

This report demonstrates the strategic localisation and upregulation of NK-1R expression in IBD colon, and thereby suggests the involvement of substance P in the pathophysiological symptoms of IBD.

Bone-marrow micrometastases in patients with brain metastases from epithelial cell tumours

Carcinoma that has metastasized to the central nervous system (CNS) poses a particular clinical problem regarding confirmation of the diagnosis and subsequent management. Prior to excision, thorough evaluation for coexisting systemic disease is essential, but current imaging techniques are limited by their spatial resolution and under-stage many patients. We evaluated the potential utility of bone-marrow evaluation for micrometastatic cells in patients with CNS metastasis. Bone-marrow aspirates were examined for cytokeratin-positive cells in 12 consecutive patients who presented with symptomatic space-occupying lesions of the CNS. These patients had previously undergone surgical excision of either gastrointestinal or breast cancers. All twelve had micrometastases in their bone marrow at the time of presentation with the CNS disease and all had a fatal outcome within 13 months. In nine of the 12 patients, bone-marrow micrometastases were the only evidence for systemic spread. Three patients had elevated serum tumour markers and two of these had radiologically detectable recurrence elsewhere. Bone-marrow micrometastases indicate concurrent systemic involvement and a poor prognosis. The results suggest that bone-marrow evaluation for systemic spread is a useful diagnostic adjunct and should be performed before considering diagnostic biopsy or excision.

Bone marrow micrometastases and gastrointestinal cancer detection and significance

Accurate staging of cancer is important, as the presence or absence of systemic spread determines treatment. The sensitivity of current imaging and biochemical techniques is suboptimal for the detection of minimal residual disease and latent metastases. This results in understaging and potential undertreatment. To improve detection of disseminated epithelial malignancy, immunohistochemical and molecular methods have been employed that search for epithelial cell-specific proteins in nonepithelial tissue. Bone marrow is mesenchymal tissue (that does not normally express epithelial cell components) and represents an accessible window for detection of micrometastatic carcinoma cells. Detection methods for epithelial cell components (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen) include immunohistochemistry, flow cytometry, reverse transcriptase polymerase chain reaction (rt-PCR), and enzyme linked immunoassay (ELISA). Micrometastatic cells in bone marrow are viable, capable of proliferation, resistant to immune attack, and insensitive to s-phase chemotherapeutic agents. Patients with carcinomas of the lung, breast, prostate, or gastrointestinal tract and in whom bone marrow micrometastases are detected have a foreshortened interval to recurrence and impaired survival. Detection of micrometastases deserves serious consideration in treatment protocols, and standardization of methods is now required.

Development of a capacitive immunosensor: a comparison of monoclonal and polyclonal capture antibodies as the primary layer

There is widespread interest in capacitance immunosensor systems which directly detect antigen binding to immobilized antibody. Our system comprises an active biolayer of antibodies bound to a silicon--silicon dioxide--silicon nitride (Si-SiO2-Si3N4) surface. As with other groups, our system initially gave poorly reproducible responses on addition of antigen. We mechanically degraded the Si-SiO2-Si3N4 surface, and the responses on addition of transferrin were monitored. The mechanical degradation allowed the affinity reaction to be 'seen' capacitively. Once the system was established, a comparison of capture antibodies was performed to establish the most effective biolayer. Three affinity reactions were examined: (a) 1D2A4, monoclonal antibody (mAb) to human transferrin, as the capture layer; (b) polyclonal goat anti-human transferrin antibody (PcAb) as the capture layer; and (c) 1D2A4 with transferrin (Tf) prebound as the capture layer. There was no response to addition of transferrin where 1D2A4 was the capture layer. Addition of transferrin when the polyclonal antibody was used as the primary layer resulted in a drop in measured capacitance. Addition of goat anti-human transferrin antibody to a device with 1D2A4 plus transferrin as the capture layer also resulted in a measured capacitance decrease. There is a difference in dielectric/blocking effectiveness between the monoclonal and polyclonal antibodies.

Comparative survival rates of human-derived probiotic Lactobacillus paracasei and L. salivarius strains during heat treatment and spray drying

Spray drying of skim milk was evaluated as a means of preserving Lactobacillus paracasei NFBC 338 and Lactobacillus salivarius UCC 118, which are human-derived strains with probiotic potential. Our initial experiments revealed that NFBC 338 is considerably more heat resistant in 20% (wt/vol) skim milk than UCC 118 is; the comparable decimal reduction times were 11.1 and 1.1 min, respectively, at 59 degrees C. An air outlet temperature of 80 to 85 degrees C was optimal for spray drying; these conditions resulted in powders with moisture contents of 4.1 to 4.2% and viable counts of 3.2 x 10(9) CFU/g for NFBC 338 and 5.2 x 10(7) CFU/g for UCC 118. Thus, L. paracasei NFBC 338 survived better than L. salivarius UCC 118 during spray drying; similar results were obtained when we used confocal scanning laser microscopy and LIVE/DEAD BacLight viability staining. In addition, confocal scanning laser microscopy revealed that the probiotic lactobacilli were located primarily in the powder particles. Although both spray-dried cultures appeared to be stressed, as shown by increased sensitivity to NaCl, bacteriocin production by UCC 118 was not affected by the process, nor was the activity of the bacteriocin peptide. The level of survival of NFBC 338 remained constant at approximately 1 x 10(9) CFU/g during 2 months of powder storage at 4 degrees C, while a decline in the level of survival of approximately 1 log (from 7.2 x 10(7) to 9.5 x 10(6) CFU/g) was observed for UCC 118 stored under the same conditions. However, survival of both Lactobacillus strains during powder storage was inversely related to the storage temperature. Our data demonstrate that spray drying may be a cost-effective way to produce large quantities of some probiotic cultures.

Differential expression of neurokinin-1 receptor by human mucosal and peripheral lymphoid cells

Substance P (SP) has been implicated in peripheral and mucosal neuroimmunoregulation. However, confusion remains regarding immunocyte expression of the receptor for SP, neurokinin-1 receptor (NK-1R), and whether there is differential NK-1R expression in the mucosal versus the peripheral immune system. In the same assay systems, we examined the expression of NK-1R in human lamina propria mononuclear cells (LPMC), peripheral blood mononuclear cells (PBMC), peripheral blood lymphocytes (PBL), monocytes, and monocyte-derived macrophages (MDM). Using standard reverse transcription (RT)-PCR, mRNA expression of both the long and the short isoforms of the NK-1R was evident in LPMC but not in PBMC, PBL, monocytes, or MDM. However, by using nested RT-PCR NK-1R mRNA expression was detected in PBMC, PBL, monocytes, and MDM. This level of expression was found to represent one NK-1R mRNA transcript in >1,000 cells. In contrast, by using competitive RT-PCR we demonstrate that LPMC express a more biologically significant level of eight NK-1R mRNA transcripts per cell. Flow cytometric detection of NK-1R expression at the protein level was evident in LPMC but not in PBMC. These findings illustrate the extreme sensitivity of nested RT-PCR and the advantages of competitive RT-PCR in comparative studies of receptor expression in different cell populations. This study suggests that, under normal conditions, readily detectable expression of NK-1R in human mononuclear cells occurs at the mucosal level rather than in the peripheral circulation.

Influence of a probiotic adjunct culture of Enterococcus faecium on the quality of cheddar cheese

Cheddar cheese has previously been shown to be an effective vehicle for delivery of viable cells of a probiotic Enterococcus faecium strain to the gastrointestinal tract. The particular strain, E. faecium PR88, has proven efficacy in the treatment of irritable bowel syndrome, and in this study it was evaluated for suitability as a starter adjunct for Cheddar cheese manufacture. When added to cheesemilk at an inoculum of 2 x 10(7) cfu/mL, the enterococcal adjunct maintained viability in Cheddar cheese at levels of up to 3 x 10(8) cfu/g during 9 months of ripening. Increased proteolysis and higher levels of some odor-active volatile compounds were observed in Cheddar cheeses containing the PR88 adjunct compared with the control throughout the ripening period. In addition, the enterococcal adjunct strain did not affect cheese composition. Although sensory evaluation showed no significant difference in flavor/aroma and body/texture scores between control and experimental cheeses, repeated comments by the commercial grader consistently described the cheeses containing PR88 as 'more advanced than the control' and as having 'better flavor'. These findings indicate that the presence of the PR88 adjunct strain in Cheddar cheese at levels of >/=10(8) cfu/g may positively influence Cheddar flavor.

Probiotics: from myth to reality. Demonstration of functionality in animal models of disease and in human clinical trials

The enteric flora comprise approximately 95% of the total number of cells in the human body and are capable of eliciting immune responses while also protecting against microbial pathogens. However, the resident bacterial flora of the gastrointestinal tract (GIT) may also be implicated in the pathogenesis of several chronic conditions such as inflammatory bowel disease (IBD). The University College Cork-based Probiotic Research Group has successfully isolated and identified lactic acid bacteria (LAB) which exhibit beneficial probiotic traits. These characteristics include the demonstration of bile tolerance; acid resistance; adherence to host epithelial tissue; and in vitro antagonism of potentially-pathogenic micro-organisms or those which have been implicated in promoting inflammation. The primary objective of this report is to describe the strategy adopted for the selection of potentially effective probiotic bacteria. The study further describes the evaluation of two members of the resulting panel of micro-organisms (Lactobacillus salivarius subsp. salivarius UCC118 and Bifidobacterium longum infantis 35624) under in vitro conditions and throughout in vivo murine and human feeding trials. Specifically, an initial feeding study completed in Balb/c mice focused upon (i) effective delivery of the probiotic micro-organisms to the GIT and evaluation of the ability of the introduced strains to survive transit through, and possibly colonise, the murine GIT; (ii) accepting the complexity of the hostile GIT and faecal environments, development of a method of enumerating the introduced bacterial strains using conventional microbiological techniques; and (iii) assessment of the effects of administered bacterial strains on the numbers of specific recoverable indigenous bacteria in the murine GIT and faeces. Additional research, exploiting the availability of murine models of inflammatory bowel disease, demonstrated the beneficial effects of administering probiotic combinations of Lactobacillus salivarius UCC118 and Bifidobacterium longum infantis 35624 in prevention of illness-related weight loss. A further ethically-approved feeding trial, successfully conducted in 80 healthy volunteers, demonstrated that yoghurt can be used as a vehicle for delivery of Lactobacillus salivarius strain UCC118 to the human GIT with considerable efficacy in influencing gut flora and colonisation.

Detection and identification of Mycoplasma from bovine mastitis infections using a nested polymerase chain reaction

A polymerase chain reaction (PCR) test was compared with culture for the detection and diagnosis of bovine Mycoplasma intramammary infection. The PCR test was applied to 24-hour Mycoplasma enrichment cultures of milk from cows with suspected mastitis and from bulk tank milk. In comparison to culture, the sensitivity and specificity of the PCR method were 96.2% and 99.1% for individual cow milk and 100% and 99.8% for the bulk tank milk, respectively. However, in discrepant cases where PCR was positive and culture was negative, the PCR test was correct; subsequent PCR tests and culturing of the individual cow's milk yielded positive results. The PCR test simultaneously detected and differentiated among 11 bovine Mycoplasma species.