Intratumoral coinjection of two adenoviruses, one encoding the chemokine IFN-gamma-inducible protein-10 and another encoding IL-12, results in marked antitumoral synergy

We have constructed a recombinant defective adenovirus that expresses functional murine IFN-gamma-inducible protein-10 (IP-10) chemokine (AdCMVIP-10). Injection of AdCMVIP-10 into s.c. tumor nodules derived from the CT26 murine colorectal adenocarcinoma cell line displayed some antitumor activity but it was not curative in most cases. Previous studies have shown that injection of similar s. c. CT26 tumor nodules with adenovirus-encoding IL-12 (AdCMVIL-12) induces tumor regression in nearly 70% of cases in association with generation of antitumor CTL activity. AdCMVIP-10 synergizes with the antitumor effect of suboptimal doses of AdCMVIL-12, reaching 100% of tumor eradication not only against injected, but also against distant noninjected tumor nodules. Colocalization of both adenoviruses at the same tumor nodule was required for the local and distant therapeutic effects. Importantly, intratumoral gene transfer with IL-12 and IP-10 generated a powerful tumor-specific CTL response in a synergistic fashion, while both CD4 and CD8 T cells appeared in the infiltrate of regressing tumors. Moreover, the antitumor activity of IP-10 plus IL-12 combined gene therapy was greatly diminished by simultaneous in vivo depletion of CD4+ and CD8+ T cells but was largely unaffected by single depletion of each T cell subset. An important role for NK cells was also suggested by asialo GM1 depletion experiments. From a clinical point of view, the effects of IP-10 permit one to lower the required gene transfer level of IL-12, thus preventing dose-dependent IL-12-mediated toxicity while improving the therapeutic efficacy of the elicited antitumor response.

Insulin-like growth factor-I reverts testicular atrophy in rats with advanced cirrhosis

The pathogenesis of hypogonadism in cirrhosis is not completely understood. The levels of insulin-like growth factor-I (IGF-I), an anabolic factor with trophic actions on testes, are reduced in cirrhosis. This study was undertaken to evaluate whether rats with advanced cirrhosis develop hypogonadism and whether the administration of IGF-I exerts beneficial effects on testicular structure and function. Wistar rats with ascitic cirrhosis induced with CCl(4) were allocated into 2 groups (n = 10, each) to receive recombinant IGF-I (20 microg x kg(-1) x d(-1), subcutaneously) or vehicle for 3 weeks. Healthy rats receiving vehicle were used as the control group (n = 10). At baseline, both cirrhotic groups showed similar deterioration of liver function tests. Compared with controls, nontreated cirrhotic rats showed decreased serum levels of IGF-I (P <.05), reduced testicular size and weight (P <.001), and intense histopathological testicular abnormalities, including reduced tubular diameters (P <.001), loss of the germinal line (P <. 001), and diminutions in cellular proliferation, spermatogenesis (P <.001), and testicular transferrin expression (P <.001). In addition, low serum testosterone (P <.01) and high serum LH (P <.01) were present in untreated cirrhotic animals. Cirrhotic rats that received IGF-I showed full recovery of testicular size and weight and of all histopathological abnormalities (P <.001 to <.01 vs. nontreated cirrhotic rats; P = ns vs. controls). Serum levels of sex hormones tended to normalize. In conclusion, IGF-I deficiency may play a pathogenetic role in hypogonadism of cirrhosis. Low doses of IGF-I for a short period of time revert testicular atrophy and appear to improve hypogonadism in advanced experimental cirrhosis.

In vitro susceptibility to gemifloxacin and trovafloxacin of Streptococcus pneumoniae strains exhibiting decreased susceptibility to ciprofloxacin

The in vitro susceptibility to trovafloxacin and gemifloxacin of Streptococcus pneumoniae strains exhibiting decreased susceptibility to ciprofloxacin (MIC > or =2 microg/ml; 30 strains with intermediate resistance [MIC 2 microg/ml] and 43 strains with complete resistance [MIC > or =4 microg/ml]) was determined. Seventy-three strains collected in a surveillance study carried out from May 1996 to April 1997 in Spain (prior to commercialisation of trovafloxacin and gemifloxacin) from patients with respiratory tract infections were tested. The antibacterial activity of gemifloxacin was affected to a lesser extent than that of trovafloxacin by the increase in the MIC of ciprofloxacin, with gemifloxacin showing significantly (P< or =0.001) better antibacterial activity than trovafloxacin in all ciprofloxacin MIC categories (MIC50/MIC90 values of 0.015/0.03, 0.015/0.06, 0.03/0.06 and 0.12/0.25 microg/ml for gemifloxacin vs. 0.12/0.12, 0.12/1, 0.25/0.5 and 2/4 microg/ml for trovafloxacin in the 2, 4, 8 and > or =16 microg/ml ciprofloxacin MIC categories, respectively). Nine (12.3%) of these 73 strains exhibited decreased susceptibility to trovafloxacin (> or =2 microg/ml), whereas all strains were inhibited by 0.25 microg/ml of gemifloxacin.

Combined gene therapy with suicide gene and interleukin-12 is more efficient than therapy with one gene alone in a murine model of hepatocellular carcinoma

BACKGROUND/AIMS

Gene therapy has emerged as a new form of treatment for unresectable hepatocellular carcinoma (HCC). We evaluate here the effect of IL-12 and the suicide gene thymidine kinase as single agents and in combination to treat experimental liver cancer.

METHODS

Recombinant adenoviruses expressing mouse interleukin-12 (AdCMVIL-12) or thymidine kinase of herpes simplex virus (AdCMVtk) or lacZ reporter gene (AdCMVlacZ) were constructed. The efficacy of the treatment was evaluated in a murine HCC model based on subcutaneous implantation of liver tumor cells (BNL).

RESULTS

Transduction of BNL cells after in vitro infection with AdCMVlacZ was very low at multiplicity of infection (moi) of 100, whereas 10-15% of cells were transduced when using moi 1,000. Similarly, production of IL-12 was detectable only in BNL cells infected with AdCMVIL-12 at moi 1,000. In vitro infection of BNL cells with AdCMVIL-12 at moi 100 did not abrogate tumorigenicity, whereas moi 1,000 resulted in inhibition of tumor growth in all mice as well as in abrogation of tumor formation in 3 out of 8 animals. In vivo studies showed that intratumor injection of AdCMVIL-12 induced a dose-dependent effect on tumor regression. However, none of the animals exhibited complete tumor elimination with this treatment. We observed that suppression of tumor growth was more intense in animals treated with the combination of AdCMVIL-12 plus AdCMVtk than in animals which received AdCMVtk or AdCMVIL-12 alone. The combined treatment resulted in a significant increase in animal survival, and 25% of treated animals were free of tumor for over 100 days without recurrence of the disease.

CONCLUSIONS

Combination of AdCMVIL-12 and AdCMVtk is more efficient than either of the two vectors alone for the treatment of the murine model of HCC used in this study.

In situ localization of anion exchanger-2 in the human kidney

Na+-independent anion exchangers (AE) are a family of membrane carriers that mediate the electroneutral exchange of Cl- for HCO3- ions across plasma membranes. They are involved in intracellular pH and cell volume regulation as well as in transepithelial acid-base transport. While anion exchanger-1 (AE1) has been localized previously in the human kidney, thus far there has been no definite report on anion exchanger-2 (AE2) in this human tissue. Accordingly, immunohistochemistry was carried out on surgical specimens of the human kidney (fixed in formalin and embedded in paraffin), using a specific AE2 monoclonal antibody. Strong immunostaining was observed at the basolateral membrane of cells of thick ascending limbs and distal convoluted tubules, colocalizing with the basal membranous labyrinth of cellular interdigitations, typical of these segments. In fact, AE2 staining was attenuated at the macula densa, where basal infoldings are scarce. Additionally, in situ hybridization experiments on formalin-fixed tissue demonstrated the presence of AE2 mRNA in the same segments of the distal nephron. On the other hand, control immunohistochemistry with a monoclonal antibody against AE1 gave the expected immunoreactivity at the basal pole of the type A intercalated cells of connecting tubules and cortical collecting ducts, and in erythrocytes. Our results indicate that, depending on the nephron segment and corresponding cell types, AE1 and AE2 proteins are differentially involved in the Na+-independent exchange of Cl- for HCO3- at the basolateral membrane of polarized kidney epithelial cells.

Tissue-specific N-terminal isoforms from overlapping alternate promoters of the human AE2 anion exchanger gene

Previously, we isolated the human AE2 (SLC4A2) gene, a member of the sodium-independent anion exchanger family. Rat ortholog of this gene was reported to drive alternative transcription yielding N-terminal variants of the AE2a message. We thus analyzed the human AE2 gene in this regard. Using HepG2 cells, two alternative first exons, each splicing to exon 3 in alternative transcripts, were found to be transcribed from overlapping sequences of intron 2. Exon 1b(1) corresponds to the rat variant "b" and encodes three initial residues (MTQ) in AE2b(1) isoform that replace the first 17 amino acids of AE2a protein, while the novel exon 1b(2) encodes eight initial residues (MDFLLRPQ) in AE2b(2) isoform. The relative abundance of AE2b(1) and AE2b(2) mRNAs was about 10% of AE2a mRNA each. Alternate promoter sequences have multiple potential binding motifs for liver-enriched factors, and dual-luciferase assays indicated that they possess the ability for driving transcription in transiently transfected HepG2 cells. Tissue survey showed that expression of human AE2b(1) and AE2b(2) transcripts is restricted to liver and kidney, while AE2a mRNA was encountered in all examined tissues. Our findings reveal a characteristic tissue-specific expression of two N-terminal variants of human AE2 from overlapping sequences within intron 2, one of which is a novel isoform.

Early predictors of response to treatment in patients with chronic hepatitis C

The term sustained response should be applied to patients with negative serum HCV-RNA and normal values of serum transaminases 6 months after interferon withdrawal. To investigate which factors identify sustained responders early during treatment we analysed 18 reports which used the definition sustained response. Eight reports, comprising 988 patients, have studied the value of early clearance of viraemia as a predictor of sustained response using multivariate analysis and all of them found that this was the strongest predictor of a sustained response. Determination of HCV-RNA 4 or 12 weeks after initiation of IFN therapy predicts treatment outcome more accurately than baseline viral load (the best pre-treatment predictor). ALT levels during the first 12 weeks of treatment have lower predictive value than early viral clearance. The sensitivity of a negative HCV-RNA test is similar at week 4 and at week 12 of therapy while the specificity and the accuracy is higher at week 4. The value of persistent viraemia for early prediction of no response is higher than 97%, with similar values at weeks 4 and 12. Persistence of HCV-RNA in serum at week 4 strongly indicates that the patient will not respond to treatment and in these cases interruption of treatment or other therapeutic options could be considered.

Adenoviral gene transfer of interleukin 12 into tumors synergizes with adoptive T cell therapy both at the induction and effector level

Tumors infected with a recombinant defective adenovirus expressing interleukin 12 (IL-12) undergo regression, associated with a cytotoxic T lymphocyte (CTL)-mediated antitumor immune response. In the present study we generated anti-CT26 CTLs by short-term coculture of CT26 cells and lymph node cells obtained from mice harboring subcutaneous CT26 tumors injected with an adenoviral vector expressing IL-12 (AdCMVIL-12), control adenovirus (AdCMVlacZ), or saline. Regression of small intrahepatic CT26 tumors in unrelated syngeneic animals was achieved with CTLs derived from mice whose subcutaneous tumors had been injected with AdCMVIL-12 but not with CTLs from the other two control groups. The necessary and sufficient effector cell population for adoptive transfer consisted of CD8+ T cells that showed anti-CT26 specificity partly directed against the AH1 epitope presented by H-2Ld. Interestingly, treatment of a subcutaneous tumor nodule with AdCMVIL-12, combined with intravenous adoptive T cell therapy with short-term CTL cultures, had a marked synergistic effect against large, concomitant live tumors. Expression of IL-12 in the liver in the vicinity of the hepatic tumor nodules, owing to spillover of the vector into the systemic circulation, appeared to be involved in the increased in vivo antitumor activity of injected CTLs. In addition, adoptive T cell therapy improved the outcome of tumor nodules transduced with suboptimal doses of AdCMVIL-12. Our data provide evidence of a strong synergy between gene transfer of IL-12 and adoptive T cell therapy. This synergy operates both at the induction and effector phases of the CTL response, thus providing a rationale for combined therapeutic strategies for human malignancies.

Gene transfer to liver cancer cells of B7-1 plus interleukin 12 changes immunoeffector mechanisms and suppresses helper T cell type 1 cytokine production induced by interleukin 12 alone

To investigate the cooperative effect of B7-1 and IL-12 in the induction of antitumor activity, we have developed retroviral vectors encoding human B7-1, murine IL-12, or both B7-1 and IL-12 coordinately. Murine transformed liver cells (BNL) were engineered to stably express B7-1, IL-12, or both by infection with corresponding retroviruses. No tumor was observed in 20, 75, and 95% of mice receiving, respectively, B7-1-, IL-12-, and B7-1/IL-12-modified tumor cells after 250 days of inoculation. In contrast, injection of parental BNL or BNL/Neo cells resulted in lethal tumor progression in all mice. Protection against rechallenge with parental tumor cells was observed only in mice who had rejected BNL/IL-12, but not in animals that rejected BNL/B7-1 or BNL/B7-1-IL-12. Growth of parental tumor cells was significantly delayed by simultaneous injection in a distant site of irradiated tumor cells engineered to express IL-12 or both B7-1 and IL-12 but not B7-1 alone. BNL/B7-1 and BNL/B7-1-IL-12 showed similar efficacy in these experiments. Antitumor immunity induced by B7, with or without IL-12, was found to depend mainly on CD4+ T cells with a minor contribution of a non-T cell mechanism; whereas the effect of IL-12 was dependent on CD8+ T cells and on non-T cell effectors. Immunization of mice with IL-12-modified BNL cells induced secretion of a Thl pattern of cytokines while immunization with cells expressing both IL-12 and B7-1 resulted in inhibition of IFN-gamma production. Immunization with BNL/B7-1-IL-12 cells in the presence of anti-human B7-1 MAb resulted in restoration of IFN-gamma production to the levels found in animals injected with BNL/IL-12 cells. To summarize, in our model coexpression of B7-1 and IL-12 in tumor cells does not result in improved antitumoral activity as compared with expression of IL-12 alone. This may be related to the fact that B7-1 changes the mechanisms of antitumor immunity and inhibits IFN-gamma production induced by IL-12 in vivo.

T(h)1 but not T(h)0 cell help is efficient to induce cytotoxic T lymphocytes by immunization with short synthetic peptides

Immunization of BALB/c mice with peptide HVSGHRMAWDMMMNWA, encompassing residues 121-135 from hepatitis C virus E1 protein, induced CD4(+) T(h)1 cells as well as a long-lasting CD8(+) cytotoxic T lymphocyte (CTL) response in vivo when the peptide was administered s.c. with or without incomplete Freund's adjuvant. Using truncated peptides from this sequence it was shown that the determinant recognized by cytotoxic T cells was encompassed by residues SGHRMAWDM. Deletion of residues from the N-terminus or the C-terminus of the wild-type peptide abrogated its helper character. When Val122 of the wild peptide was replaced by Ala, the ability to induce a cytotoxic response was lost concomitantly with the loss of the T(h)1 pattern of cytokine production. Interestingly, the Ala-modified peptide, when co-immunized with a peptide encompassing residues 323-329 from ovalbumin (OVA), which is able to induce a T(h)1 response in BALB/c mice, restored the capacity of the modified peptide to induce CTL. However, co-immunization of the Ala-modified peptide with a peptide encompassing residues 106-118 from sperm whale myoglobin, which induces a T(h)0 cytokine profile in BALB/c mice, was much less efficient than the OVA peptide to restore CTL induction. These results demonstrate that CTL induction with a short synthetic peptide requires that this peptide contains domains recognized by T(c) cells as well as by T(h)1 cells. For those peptides that do not contain this type of T(h) domain, competent T cell help can be provided by co-immunization with a distinct peptide that is able to stimulate a T(h)1 response.

Airway inflammation and altered alveolar macrophage phenotype pattern after repeated low-dose allergen exposure of atopic asthmatic subjects

BACKGROUND

The alveolar macrophage (AM) constitutes an important link between pulmonary innate and adaptive immunity due to its antigen-presenting capacity and ability to express different immunomodulating mediators. The role of AMs in the pathogenesis of allergic inflammation has yet to be fully determined.

OBJECTIVE

To investigate clinical effects and any change in the AM phenotype pattern after inhalation of sub-clinical doses of allergen by asthmatic patients.

METHODS

Eight subjects with allergic asthma underwent repeated low-dose allergen provocations equivalent to 10% of PD20. AMs recovered with bronchoalveolar lavage (BAL) were characterized by flow cytometric analysis of adhesion molecules, co-stimulatory molecules and markers for AM population activation and heterogeneity.

RESULTS

An allergic airway inflammation, sub-clinical in six out of eight subjects, was obtained after low-dose allergen provocations, as determined by increased airway methacholine reactivity, increased BAL fluid total cell and eosinophil counts and increased serum ECP levels. The AMs showed a post-challenge altered phenotype pattern with a decreased expression of CD11a, CD16, CD71 and HLA class I and an increased expression of CD11b and CD14. The AMs were positive for CD83 and a weak post-challenge increase in the CD83 expression was found.

CONCLUSION

Repeated low-dose allergen exposure induces an allergic airway inflammation in asthmatic subjects. The inflammation is associated with an altered AM phenotype pattern, consistent with an influx of monocytes and a hypothetical increased accessory cell function in the airways, possibly contributing to the development and sustenance of airway inflammation in asthma.

Activity of voriconazole: post-antifungal effect, effects of low concentrations and of pretreatment on the susceptibility of Candida albicans to leucocytes

This study examined: (i) the post-antifungal effect (PAFE) of Voriconazole (UK 109,496) on Candida albicans, at 2 concentrations (MIC and 4 x MIC) in the presence or absence of 10% human serum; (ii) the activity of low concentrations of the drug (1/4 x MIC) on yeasts that had previously been exposed to Voriconazole (PAFSE) with or without 10% human serum; and (iii) the effect of Voriconazole pretreatment on the fungicidal activity of leucocytes and serum against C. albicans (PALE). Two concentrations (0.25 and 1 mg/l) of Voriconazole induced no PAFE against C. albicans between -4.3 and -1.4 h, but when the assays were performed in the presence of serum, positive and concentration-dependent PAFEs were obtained (0.2-4.1 h). Pretreated yeasts were more susceptible than untreated yeasts to low concentrations (0.0625 mg/l) of Voriconazole, so the drug showed positive PAFSE that was dependent on the concentration used in pretreatment without serum (0.3-1.9 h) or with 10% human serum (0.5-2.5 h). Pretreatment of the growing C. albicans cells with Voriconazole (0.25 mg/l) increased their vulnerability to killing by leucocytes during the last 2 h (p < 0.05), leading to PALE of 2 h. The results suggest that these effects might be used to evaluate the in vivo activity of an antifungal agent. The sum of the durations of these effects (PAFE, PAFSES and PALE) cause a considerable delay in yeast growth in treated cultures compared with control cultures.

Regression of colon cancer and induction of antitumor immunity by intratumoral injection of adenovirus expressing interleukin-12

Interleukin-12 (IL-12) has been shown to possess potent immunoregulatory and antitumoral effects. We have evaluated the anti-oncogenic potential and the mechanisms of the antitumoral effect of in vivo adenovirus-mediated transfer of IL-12 gene in a murine model of colon cancer. AdCMVIL-12 was constructed to permit coordinated production of p40 and p35 subunits of IL-12 gene to obtain the maximum IL-12 bioactivity. Infection of murine colon cancer CT-26 cells in vitro with AdCMVIL-12 resulted in the production of high levels of IL-12. In vivo gene therapy of colon cancer nodules by intratumoral injection of AdCMVIL-12 induced a local increase in IL-12 and interferon-gamma levels and a complete regression of the tumor in 26 of 34 (76%) mice. Tumor disappeared between days 7 and 10 after vector administration. The antitumoral effect was mediated by CD8+ T cells and was associated with the generation of cytotoxic T lymphocytes against colon cancer cells. Animals that eliminated the tumor were protected against a second administration of neoplastic cells. Treatment with AdCMVIL-12 of one tumor nodule also caused regression of established tumors at distant sites. These data demonstrate that AdCMVIL-12 is a useful therapeutic tool for established colon cancer in mice and should be considered for application in humans.

Ex-vivo expansion and maturation of CD34-positive hematopoietic progenitors optimization of culture conditions

The aim of this study was to look for an ex vivo culture system for clinical application. We evaluated the ex vivo expansion of peripheral blood CD34+ cells in gas-permeable bags and whether or not an exogenous protein source would be required in these kind of cultures. We also evaluated maturation of the cells during culture. Cells were cultured for 15 days in medium supplemented with SCF, G-CSF, IL3 and IL6. The bags supported the expansion of hematopoietic cells in a similar manner to small scale flasks system: (a) the expansion means of total nucleated cells on day +5 were 12.5-fold for bag versus 5-fold for flask, on day +10 were 44.12-fold for bag versus 41-fold for flask and on day +15 were 67.7-fold for bag versus 84.2-fold for flask, (b) the peak values of CFU-GM were reached on day +10 (9.2-fold for bag vs. 12-fold for flask), and (c) maximal expansion of CD15+/CD11b- population occurred on day +10 (517.5-fold for bag vs. 2959.2-fold for flask). So, we did not find any advantages by culturing further than day +10. We subsequently investigated the use of serum-free medium. The study showed better results when we used medium supplemented with autologous plasma versus serum-free system. In summary, these data described a strategy of culture clinically feasible and safe, using gas-permeable bags, and the kinetics and differentiation of neutrophils and neutrophil precursors from selected CD34+ cells in liquid cultures. Ex vivo expansion of this population might result in earlier engraftment as compared with that for selected stem cells alone.

Antioxidant status and glutathione metabolism in peripheral blood mononuclear cells from patients with chronic hepatitis C

BACKGROUND/AIMS

Oxidative stress could play a role in the pathogenesis of hepatitis C virus infection. We investigated the oxidant/antioxidant status in peripheral blood mononuclear cells from patients with chronic hepatitis C and controls.

METHODS/RESULTS

Lipid peroxidation products and superoxide dismutase activity in peripheral blood mononuclear cells were higher in chronic hepatitis C patients than in healthy subjects while glutathione S-transferase activity was reduced in patients as compared to controls. Catalase, glutathione peroxidase and glutathione reductase were similar in chronic hepatitis C and normal individuals. No statistically significant differences were found between patients and controls with regard to glutathione levels in peripheral blood mononuclear cells, but 35% of patients with chronic hepatitis C showed values of glutathione and oxidized glutathione which were below and above, respectively, the limits of normal controls. Finally, the glutathione synthetic capacity of the cytosol of peripheral blood mononuclear cells was significantly higher in patients than in controls, indicating increased glutathione turnover in lymphocytes from patients with chronic hepatitis C.

CONCLUSIONS

Oxidative stress is observed in peripheral blood mononuclear cells from chronic hepatitis C patients. This process might alter lymphocyte function and facilitate the chronicity of the infection.

Does the degree of penicillin susceptibility of Streptococcus pneumoniae affect the bactericidal activity of co-amoxiclav versus oral cephalosporins at physiological concentrations? An in vitro pharmacodynamic simulation

An in vitro model simulating amoxicillin-clavulanic acid (co-amoxiclav) versus oral cephalosporin serum concentrations was used to explore activity over time against penicillin-susceptible and non-susceptible Streptococcus pneumoniae. Initial inoculum reduction > 4 log cfu/ml (>99.9%) was obtained with co-amoxiclav against both strains. Cefuroxime, cefpodoxime and cefaclor achieved a similar reduction against the susceptible strain, but no reduction against the non-susceptible strain.

Intratumoral injection of bone-marrow derived dendritic cells engineered to produce interleukin-12 induces complete regression of established murine transplantable colon adenocarcinomas

Stimulation of the antitumor immune response by dendritic cells (DC) is critically dependent on their tightly regulated ability to produce interleukin-12 (IL-12). To enhance this effect artificially, bone marrow (BM)-derived DC were genetically engineered to produce high levels of functional IL-12 by ex vivo infection with a recombinant defective adenovirus (AdCMVIL-12). DC-expressing IL-12 injected into the malignant tissue eradicated 50-100% well established malignant nodules derived from the injection of two murine colon adenocarcinoma cell lines. Successful therapy was dependent on IL-12 transfection and was mediated only by syngeneic, but not allogeneic BM-derived DC, indicating that compatible antigen-presenting molecules were required. The antitumor effect was inhibited by in vivo depletion of CD8+ T cells and completely abrogated by simultaneous depletion with anti-CD4 and anti-CD8 mAbs. Mice which had undergone tumor regression remained immune to a rechallenge with tumor cells, showing the achievement of long-lasting systemic immunity that also was able to reject simultaneously induced concomitant untreated tumors. Tumor regression was associated with a detectable CTL response directed against tumor-specific antigens probably captured by DC artificially released inside tumor nodules. Our results open the possibility of similarly treating the corresponding human malignancies.

Conversion of liver transplant recipients on cyclosporine with renal impairment to mycophenolate mofetil

The management of liver transplant recipients with renal function impairment remains controversial because cyclosporine withdrawal from triple immunosuppression regimens may be followed by graft rejection. A nonnephrotoxic and powerful immunosuppressant such as mycophenolate mofetil (MMF) could allow a reduction of cyclosporine dosage or its withdrawal and an improvement in renal function in these patients. Eleven patients with serum creatinine levels greater than 1.5 mg/dL, normal graft function, and a rejection-free period of at least 1 year started MMF at a dose of 2000 mg/d (reduced in case of adverse events) while cyclosporine dosage was slowly reduced. At last follow-up (63 +/- 5 weeks), 7 patients remained free of cyclosporine (6 of those patients are also free of steroids), 2 patients reduced their cyclosporine dose, and 2 patients developed mild acute rejection that responded to a switch to tacrolimus therapy. Serum creatinine and urea levels in the 7 patients free of cyclosporine decreased from 2.22 +/- 0.13 to 1.90 +/- 0.19 mg/dL (P =.05) and 0.95 +/- 0.10 to 0.60 +/- 0.10 g/L (P <.001), respectively. Creatinine clearance increased from 38.16 +/- 5.60 to 47.01 +/- 6. 76 mL/min (P =.005). Control of arterial hypertension also improved. Tolerance to MMF was good, but 6 patients required dose reductions, mainly because of asymptomatic anemia. In conclusion, in liver transplant recipients with stable graft function, MMF may allow cyclosporine dose reduction or discontinuation, thus improving renal function and the control of arterial hypertension. This change of treatment must be carefully monitored because of the frequent need for MMF dose reduction and the risk for rejection.

Unmasking of the trigemino-accessory reflex in accessory facial anastomosis

OBJECTIVE

To evaluate the possible blink reflex responses in facial muscles reinnervated by the accessory nerve.

METHOD

Eleven patients with a complete facial palsy were submitted to a surgical repair by an accessory facial nerve anastomosis (AFA). In this pathological group, blink reflex was studied by means of percutaneous electrical stimulation of the supraorbital nerve and recording from the orbicularis oculi muscle. A control group comprised seven normal people and seven patients with a complete Bell's facial palsy; in this group, responses on the sternocleidomastoideus (SCM) muscles were studied after supraorbital nerve stimulation.

RESULTS

All the patients with AFA showed a consistent degree of facial reinnervation. Ten out of the 11 patients with AFA showed reflex responses; in six, responses were configured by a double component pattern, resembling the R1 and R2 components of the blink reflex; three patients had an R1-like response and one patient showed a unique R2 component. Mean values of latencies were 15.2 (SD 4.6) ms for the R1 and 85.3 (SD 9.6) ms for the R2. In the control group, eight out of 14 people had evidence of reflex responses in the SCM muscles; these were almost exclusively configured by a bilateral late component (mean latency 63.5 (SD15.9) ms) and only one of the subjects showed an early response at 11 ms.

CONCLUSION

The trigemino-accessory reflex response in the pathological group was more complex and of a significantly higher incidence than in the control group. These differences could be tentatively explained by a mechanism of synaptic plasticity induced by the impairment of the efferent portion of the reflex. This could unmask the central linking between the trigeminal and the accessory limbs of the reflex. The findings described could be a demonstration of neurobionomic function in the repairing process of the nervous system.

[Effect of subinhibitory concentrations of various antimicrobials on insoluble glucan production, polystyrene adherence and bacterial surface hydrophobicity of Streptococcus sobrinus]

The effect of subinhibitory concentrations (1/2, 1/4, 1/8 of the MIC) of amoxicillin, teicoplanin, clindamycin and erythromycin on the factors influencing the adherence and pathogenicity of Streptococcus sobrinus was evaluated. These factors included insoluble glucan, polystyrene adherence and bacterial surface hydrophobicity. Insoluble glucan was detected using a spectrophotometric method; polystyrene adherence was assessed using microtiter plates; and surface hydrophobicity was determined using a biphasic system (water/p-xiline). Amoxicillin and teicoplanin induced a statistically significant decrease in adherence at subinhibitory concentrations, and they also decreased the hydrophobicity. However, clindamycin and erythromycin were unable to decrease these parameters. The adherence and hydrophobicity of S. sobrinus was also dependent on the concentration of sucrose in the culture medium.

Infection control. Dazed and confused

This research project aims to uncover the practical concerns of health care staff on a hospital ward while attempting to implement isolation precaution guidelines for patients with Clostridium difficile-associated diarrhoea (CDAD) and methicillin-resistant Staphylococcus aureus (MRSA). The project is still in progress so this article describes the research methods used and some preliminary findings.

Assessment of biliary bicarbonate secretion in humans by positron emission tomography

BACKGROUND & AIMS

Positron emission tomography (PET) allows imaging and quantitative analysis of organ functions in basal and stimulated conditions. We have applied this method to the study of biliary bicarbonate secretion in humans.

METHODS

PET was performed in 5 healthy subjects and 13 patients with hepatobiliary disorders after intravenous injection of NaH11CO3. In each case the study was performed in basal conditions and after secretin stimulation. Positron emission from the hepatic area was scanned, and normalized uptake values for parenchymal and hilar regions were estimated.

RESULTS

In healthy individuals, the injection of NaH11CO3 resulted in a peak uptake of the label in parenchymal and hilar regions 2-3 minutes after the injection. In both normal and cirrhotic subjects, secretin administration increased bicarbonate uptake in the parenchymal region, followed by accumulation of the label in the perihilar area. Normal basal uptake with absent response to secretin was registered in extrahepatic biliary obstruction and in untreated primary biliary cirrhosis (PBC). The secretin response was present in patients with PBC undergoing treatment with ursodeoxycholic acid.

CONCLUSIONS

PET allows investigation of biliary bicarbonate secretion in humans. An impaired response to secretin was observed in cholestatic conditions. Preliminary data suggest that ursodeoxycholic acid might improve the response to secretin in PBC.