Effect of nitrate and incubation conditions on the production of catalase and nitrate reductase by staphylococci

The objective of this work was to study the production of catalase and nitrate reductase by staphylococci in order to understand their role in lipid oxidation during sausage manufacturing. Catalase and nitrate reductase were measured in resting cells and supernatants of staphylococci grown in different conditions. All staphylococci (except S. warneri) synthetized nitrate reductase. In static condition, the synthesis was maximal during exponential growth phase, whereas in shaking condition, the synthesis was maximal at the beginning of stationary phase. The production of nitrate reductase was increased in presence of nitrate, this effect was particularly important for the two S. carnosus strains which exhibited the highest activity. For all staphylococci, the production of catalase was maximal at the end of the exponential growth phase. The lowest amount of catalase was produced by S. warneri and the highest by S. carnosus. Only S. xylosus 873 and S. saprophyticus 852 released high amounts of catalase in the supernatant growth. Staphylococci produced higher amounts of catalase in shaking conditions. Addition of nitrate in the growth media favoured the synthesis of catalase, with a pronounced effect for S. carnosus. Nitrate also favoured the release of catalase.

Tacrolimus in dermatology

BACKGROUND

Tacrolimus (FK 506), a metabolite of the fungus Streptomyces tsukubaensis, is an anti-T-cell drug. It acts by inhibiting the production of IL-2, IL-3, IL-4, TNFa, and GM-CSF. More potent and with slightly less secondary effects than cyclosporine, it has been the object of considerable interest, especially in conditions that could benefit from the latter.

OBJECTIVE

In psoriasis, a placebo-controlled double-blind study has shown oral tacrolimus at 0.1 mg/kg/day to be effective in controlling recalcitrant lesions. In human, small studies have reported tacrolimus ointment to be effective in controlling acute contact dermatitis. Short-term trials of topical tacrolimus in the treatment of atopic dermatitis have recently shown excellent results in both adults and children. In animal studies of hair growth disorders, topical tacrolimus induces anagen and protects from chemotherapy-induced alopecia. Animal studies with the ointment for the prevention of skin graft rejection, lupus dermatoses, and skin papilloma formation have also shown to be promising.

CONCLUSIONS

There are case reports of pyoderma gangrenosum, Sezary's syndrome, and Behcet's disease successfully treated with oral tacrolimus but, because of their small number, they remain anecdotal at this point.

Partial lipodystrophy associated with a type 3 form of membranoproliferative glomerulonephritis

Partial lipodystrophy can be associated with a glomerulonephritis, most commonly a membranoproliferative form, of either the classic type 1 or the type 2 (dense deposit) disease in 50% of cases. We describe a woman affected by partial lipodystrophy associated with a type 3 form of membranoproliferative glomerulonephritis. To our knowledge, this is the first reported case in the English-language literature.

Redox-modulating agents target NOX2-dependent IKKε oncogenic kinase expression and proliferation in human breast cancer cell lines

Oxidative stress is considered a causative factor in carcinogenesis, but also in the development of resistance to current chemotherapies. The appropriate usage of redox-modulating compounds is limited by the lack of knowledge of their impact on specific molecular pathways. Increased levels of the IKKε kinase, as a result of gene amplification or aberrant expression, are observed in a substantial number of breast carcinomas. IKKε not only plays a key role in cell transformation and invasiveness, but also in the development of resistance to tamoxifen. Here, we studied the effect of in vitro treatment with the redox-modulating triphenylmethane dyes, Gentian Violet and Brilliant Green, and nitroxide Tempol on IKKε expression and cell proliferation in the human breast cancer epithelial cell lines exhibiting amplification of IKKε, MCF-7 and ZR75.1. We show that Gentian Violet, Brilliant Green and Tempol significantly decrease intracellular superoxide anion levels and inhibit IKKε expression and cell viability. Treatment with Gentian Violet and Brilliant Green was associated with a reduced cyclin D1 expression and activation of caspase 3 and/or 7. Tempol decreased cyclin D1 expression in both cell lines, while activation of caspase 7 was only observed in MCF-7 cells. Silencing of the superoxide-generating NOX2 NADPH oxidase expressed in breast cancer cells resulted in the significant reduction of IKKε expression. Taken together, our results suggest that redox-modulating compounds targeting NOX2 could present a particular therapeutic interest in combination therapy against breast carcinomas exhibiting IKKε amplification.

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IKKε kinase is amplified in MCF7 and ZR75.1 breast cancer cells.

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Brilliant Green, Gentian Violet and Tempol reduce superoxide levels in MCF7 and ZR75.1 cells.

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Brilliant Green, Gentian Violet and Tempol inhibit IKKε expression in MCF7 and ZR75.1 cells.

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IKKε overexpression in breast cancer cells is dependent on NOX2.

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Brilliant Green, Gentian Violet and Tempol reduce MCF7 and ZR75.1 cell viability.

A new sensitive membrane based ELISA technique for instantaneous D.Dimer evaluation in emergency

D.Dimer is currently used as a diagnotic help in thromboembolic events. The first application widely validated concerns the exclusion diagnosis of deep vein thrombosis and pulmonary embolism. In this context D.Dimer measurements must be performed individually and they must offer a good accuracy in evaluating the clinical decision threshold which is of 0.5 micrograms/ml when D.Dimer is expressed as initial fibrinogen equivalent. For this objective we report a new membrane based ELISA technique, which uses an immunofiltration device and two complementary monoclonal antibodies. The first one is coated onto the membrane and is used for the D.Dimer capture. The bound analyte is then revealed later using the second monoclonal antibody coupled to alkaline phosphatase. The assay is performed in less than 10 minutes and it can be used instantaneously by the clinical laboratories in emergency situations. Only 200 microliters of a standard citrated plasma are required. All samples containing more than 0.5 micrograms/ml D.Dimer produce a color development which intensity is a relation of the D.Dimer concentration. All specimen with levels below 0.3 micrograms/ml give negative tests, whereas a grey zone is present between 0.3 and 0.5 micrograms/ml. This assay offers all the specifications required by its applications to the exclusion diagnosis of deep vein thrombosis and pulmonary embolism.

Hypergammaglobulinemic purpura in systemic autoimmune rheumatic diseases: predictive value of anti-Ro(SSA) and anti-La(SSB) antibodies and treatment with indomethacin and hydroxychloroquine

OBJECTIVE

To define the clinical manifestations, autoantibody associations, optimal treatment, and prognosis of hypergammaglobulinemic purpura associated with systemic autoimmune rheumatic diseases.

METHODS

Of 303 consecutive patients with systemic autoimmune rheumatic diseases evaluated over 5 years, 17 French Canadian patients with hypergammaglobulinemic purpura with systemic lupus erythematosus (SLE) (n = 12) or another systemic autoimmune rheumatic disease (n = 5) were identified and followed prospectively. Mild secondary Sjörgren's syndrome developed in 9 (53%) patients.

RESULTS

Sixteen (94.1%) patients were women. Attacks of hypergammaglobulinemic purpura occurred in the pretibial (76.5%) or perimalleolar (70.5%) areas or the dorsal aspect of the feet (52.9%). Triggering factors included walking, prolonged standing, and alcohol intake. The mean duration of attacks was 6.1 days. Systemic manifestations consistent with a flare of the underlying systemic autoimmune rheumatic diseases accompanied hypergammaglobulinemic purpura attacks in 15 (88%) patients. Arthralgias (n = 13, 86.6%), arthritis (n = 9, 69.2%), and periarthritis were characterstically localized adjacent to the purpura. Anti-Ro antibodies were expressed in all (100%) patients with hypergammaglobulinemic purpura with SLE, but in only 11 (28.9%) of 38 consecutive patients with SLE without hypergammaglobulinemic purpura (P < 0.000001, odds ratio 84, 95% confidence interval 4.6, 1525). The positive predictive values for hypergammaglobulinemic purpura in SLE were: anti-Ro plus anti-La 73%, anti-La 57%, and anti-Ro 52%. The negative predictive value of anti-Ro was 100%. Although 11 (92%) patients with SLE with anti-Ro expressed anti-52 kDa Ro [4 (36.3%) of whom also expressed anti-60 kDa Ro], this frequency was not greater than in anti-Ro positive patients with SLE without hypergammaglobulinemic purpura. The effects of indomethacin or hydroxychloroquine were assessed over 6 months in 8 patients with recurrent incapacitating hypergammaglobulinemic purpura. Complete (n = 4) or partial (n = 4) remission of hypergammaglobulinemic purpura occurred. In 5 additional patients with severe hypergammaglobulinemic purpura, attacks stopped with prednisone 25 to 60 mg daily. The mean duration of hypergammaglobulinemic purpura followup was 5.4 years (range 1-6 years). At last followup, hypergammaglobulinemic purpura had resolved in 11 (64.7%) patients despite persistently abnormal serology.

CONCLUSION

In the absence of anti-Ro antibodies, a presumptive diagnosis of hypergammaglobulinemic purpura secondary to SLE should be questioned. Prednisone should be used only in severe hypergammaglobulinemic purpura. Indomethacin and hydroxychloroquine are of value in the treatment of milder hypergammaglobulinemic purpura.

Alterations in Ca2+ signal transduction in critically ill surgical patients

BACKGROUND

Despite improvements in supportive care and pharmacologic therapies, sepsis and related disorders such as systemic inflammatory response syndrome (SIRS) continue to be a leading cause of death in the intensive care unit. We hypothesized that immune dysfunction in this setting may in part be mediated at the level of early signal transduction in monocytes and neutrophils as manifested by changes in intracellular free Ca2+.

METHODS

Monocytes and neutrophils were isolated from patients in the intensive care unit who met the criteria for SIRS and from normal volunteers. Cells were loaded with the Ca(2+)-sensitive fluorescent dye Indo-1 and stimulated with the chemotactic peptide f-Met-Leu-Phe (fMLP). Changes in intracellular calcium ion concentration were measured by flow cytometry.

RESULTS

Patient monocytes exhibited a decreased Ca2+ flux (43% +/- 3.1%) as compared with normal monocytes (63% +/- 2.5%) (p < 0.05). Patient neutrophils also exhibited a decreased Ca2+ flux in response to fMLP of 58% +/- 3.7% versus 69.3% +/- 3.1% for normal neutrophils (p < 0.05). Incubation of patient cells in normal plasma reversed this dysfunction and showed an improved Ca2+ flux to 60% +/- 2.7% for monocytes and 71% +/- 3.7% for neutrophils (p < 0.05). Conversely, calcium flux was decreased in both normal monocytes (42.3% +/- 3.1%) and normal neutrophils (55.4% +/- 3.8%) after incubation in SIRS patient plasma (p < 0.05). Incubation of normal monocytes and neutrophils in interleukin-1, interleukin-2, interleukin-6, tumor necrosis factor, or lipopolysaccharide did not show a statistically significant alteration in calcium flux in response to fMLP.

CONCLUSIONS

Patients with SIRS exhibit alterations in early signal transduction after stimulation with fMLP in monocytes and neutrophils. This effect appears to be mediated by a soluble factor because the defect in SIRS patient cells can be reversed by incubation in normal plasma and normal cells appear to acquire this defect after incubation in patient plasma. Further studies are underway to identify the factor or factors responsible for this functional defect.

Expansion and manipulation of natural killer cells in patients with metastatic cancer by low-dose continuous infusion and intermittent bolus administration of interleukin 2

Interleukin 2 (IL-2) administered at low doses for prolonged periods can markedly expand the number of CD56(+) natural killer (NK) cells in patients with metastatic cancer. The cytotoxic capacity of NK cells obtained from patients receiving IL-2 in vivo can be dramatically augmented by additional exposure to IL-2 in vitro. These observations formed the basis of a clinical trial in which patients with metastatic cancer were treated with low-dose continuous daily infusions of IL-2 to increase the number of their NK cells in conjunction with intermittent boluses of additional IL-2 to stimulate this expanded pool of cytotoxic cells. Twenty-three patients were registered to receive IL-2 at 4.5 x 10(5) units/m2/day for 8 weeks by continuous i.v. infusion. After 4 weeks of "priming" with low-dose continuous infusion IL-2, cohorts of three to five patients received 5 weekly 2-h boluses of IL-2 at doses ranging from 2.5 x 10(5) units/m2 to 1.0 x 10(6) units/m2. Low-dose continuous infusion IL-2 was usually well tolerated; 2-h bolus infusions of IL-2 were often associated with high fevers and constitutional symptoms that resolved after several hours. Low-dose continuous infusion IL-2 resulted in the progressive expansion of circulating CD56(+)CD3(-) NK cells. In contrast, each bolus infusion of IL-2 resulted in an immediate dramatic decrease in both the number of NK cells and activated T lymphocytes with recovery noted within 24 h. Bolus doses of IL-2 as low as 2.5 x 10(5) units/m2 were capable of producing these effects. Cytolytic activity against NK-sensitive and -resistant targets correlated with the presence of circulating activated NK cells. Our results demonstrate that NK cells expanded by low-dose continuous infusions of IL-2 can be further activated in vivo by exposure to very low doses of IL-2 as a 2-h i.v. bolus. This capacity to manipulate human NK cells in vivo through varying the dose and schedule of IL-2 administration may help in defining the therapeutic potential of these cytotoxic effectors in the treatment of both neoplastic and infectious diseases.

Validation of an internal method for the diagnosis of infections with Chlamydophila abortus and Coxiella burnetii by real-time multiplex PCR

Chlamydophila abortus and Coxiella burnetii are one of the major pathogens implicated in abortion in cattle. Their characteristic of obligate intracellular bacteria, and of zoonotic agents, makes their culture difficult in diagnostic laboratories, and the traditional tools of diagnosis (detection of sera antibodies by ELISA, Stamp's coloration) encounter specificity, sensitivity and interpretability limits. Individual PCR have recently been developed. Nevertheless, their income/cost is a limiting factor for breeders. As the symptoms are not specific, the request for analysis often concerns the two valences. Consequently, the development and the validation of an internal multiplex PCR appears to be a suitable solution.

Defective activation of mitogen-activated protein kinase after allogeneic bone marrow transplantation

Allogeneic bone marrow transplant (BMT) recipients have increased susceptibility to infections for prolonged periods after phenotypic reconstitution of donor cells. This immunodeficiency status is characterized by multiple T-cell functional abnormalities. This study was designed to investigate several signaling pathways involved in T-cell activation during this period of immune deficiency. In initial experiments using equal numbers of CD3+ cells or highly purified T-cell subpopulations obtained from normal controls and BMT recipients, we confirmed that abnormal T-cell proliferation after CD3 cross-linking, phytohemagglutinin stimulation, or phorbol myristate acetate (PMA) stimulation of peripheral blood mononuclear cells from BMT recipients was due to a qualitative T-cell deficiency rather than to low numbers of circulating T cells. We next investigated the ability of the T-cell receptor/CD3 complex to transduce signals via receptor-associated protein tyrosine kinases. In all BMT recipients, CD3 cross-linking induced protein tyrosine phosphorylation of several proteins in a similar fashion to that seen in controls, including phosphorylation of a 21-kD protein that represents the zeta subunit of the receptor itself. Further investigation showed that CD3 cross-linking and PMA stimulation did not increase 42-44-kD mitogen-activated protein kinase (MAPK) activity. The failure of MAPK activation in BMT recipients occurred despite tyrosine phosphorylation of the 42-44-kD proteins, which, in normal controls, parallels enzyme activation. Our results indicate that T-cell immunodeficiency in BMT recipients is associated with a selective failure of MAPK activation, possibly related to abnormal posttranslational positive regulation of this enzyme.

Recombinant interleukin-2 infusions and decreased IgG2 subclass concentrations

The administration of low doses of recombinant interleukin-2 (rIL-2) in vivo to patients with malignant neoplasms has been demonstrated to selectively increase the number of circulating natural killer (NK) cells in these patients. Recent evidence from SCID mouse models suggests that IgG subclass levels can be influenced by the presence and activity of NK cells. Therefore, we sought to examine the effect of rIL-2 infusions on human serum IgG subclass concentrations. We determined serum IgG subclass concentrations in 27 cancer patients receiving low-dose rIL-2 by daily continuous intravenous infusion. Eleven of these patients had active, metastatic, nonhematologic tumors; 16 patients had received IL-2 when they were in a minimal residual disease state after autologous or allogeneic bone marrow transplantation. Samples obtained before beginning IL-2 therapy and 8 to 10 weeks into therapy were tested. Treatment with IL-2 resulted in an increase in the percentage of CD56+ NK cells from 18% to 54% (P = .0001). A significant decrease in geometric mean IgG2 concentration from 2,017 micrograms/mL to 1,655 micrograms/mL was noted over this time interval (P = .03). Furthermore, the geometric mean IgG2 concentration after treatment was significantly lower than that of healthy controls (P = .026). In contrast, no significant changes in serum IgG1, IgG3, or IgG4 were noted during r-IL2 infusions. Our data suggest that rIL-2 treatment selectively decreases serum IgG2 concentrations. We speculate that increased NK cells mediate downregulation of human serum IgG2.

Prediction of graft-versus-host disease by phenotypic analysis of early immune reconstitution after CD6-depleted allogeneic bone marrow transplantation

Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality following allogeneic bone marrow transplantation (BMT). Because GVHD is frequently refractory to treatment, the early identification of high-risk patients could have significant clinical value. To identify such patients, we examined early immunologic recovery in 136 patients with hematologic malignancies who received anti-T12 (CD6)-purged allogeneic bone marrow over a 9-year period. The majority of patients received marrow from HLA-matched sibling donors after ablation with cyclophosphamide and total body irradiation. No patients received any immune suppressive medications for GVHD prophylaxis. The fraction and absolute numbers of peripheral blood lymphocytes (PBL) expressing the CD3, CD4, CD8, and CD56 surface antigens were determined weekly by immunofluorescence analysis in patients beginning 8 to 14 days (week 2) after marrow infusion. Results in patients who did or did not subsequently develop GVHD post-BMT were compared. Within 2 weeks of marrow infusion, patients who developed grades 2-4 GVHD had significantly higher percentages and absolute numbers of CD8+ T cells and a lower fraction of CD56+ natural killer (NK) cells than individuals who remained free of GVHD. Thirty-five percent of patients whose PBL were greater than 25% CD8+ in the second posttransplant week developed GVHD, compared with only 3% of patients who had < or = 25% CD8+ cells (odds ratio 37.8; 95% confidence interval [CI] 4.1 to 397). A subgroup of patients at very high risk for GVHD could be identified based on the combined frequency of CD8+ T cells and NK cells in blood. Seventy-five percent of patients with greater than 25% CD8+ cells and < or = 45% CD56+ cells during week 2 post-BMT developed GVHD, compared with only 11% of the remaining patients (odds ratio 24.9; 95% CI, 5.3 to 117.0). None of the 23 patients with both less than 25% CD8+ cells and greater than 45% CD56+ cells in the second posttransplant week developed grades 2-4 GVHD. Our findings indicate that CD8+ T cells play an important role in the pathogenesis of GVHD in humans. Analysis of immune reconstitution early after BMT is useful in predicting the onset of GVHD and can help direct the implementation of treatment strategies before the appearance of clinical manifestations. Such interventions may decrease the morbidity and mortality associated with allogeneic BMT and ultimately improve overall survival.