Preparation of antioxidant active films based on chitosan: diffusivity study of α-tocopherol into food simulants.

New active films based on chitosan and polycaprolactone blends and containing α-tocopherol were designed for food packaging applications. Mechanical properties, stability against temperature and swelling degree in 50 % ethanol (v/v) were evaluated. Migration kinetics of α-tocopherol from the developed films into butter and food simulants [50 % ethanol (v/v), 95 % ethanol (v/v), and isooctane] at different temperatures were studied. α-Tocopherol was quantified in the food simulants by means of high performance liquid chromatography with diode-array detection at 292 nm. The proposed method exhibited a good sensitivity with a limit of detection of 0.1 mg/L. The kinetics release of α-tocopherol was characterized by determining the partition and the diffusion coefficients by using a mathematical modeling based on Fick's Second Law. The diffusion coefficients obtained ranged between 1.03 × 10(-13) and 2.24 × 10(-12) cm(2)/s for 95 % ethanol (v/v) at 4 and 20 °C, respectively. Developed films maintained the antioxidant activity for more than 20 days.

A hepatitis C virus NS5A phosphorylation site that regulates RNA replication.

The hepatitis C virus NS5A protein is essential for RNA replication and virion assembly. NS5A is phosphorylated on multiple residues during infections, but these sites remain uncharacterized. Here we identify serine 222 of genotype 2a NS5A as a phosphorylation site that functions as a negative regulator of RNA replication. This site is a component of the hyperphosphorylated form of NS5A, which is in good agreement with previous observations that hyperphosphorylation negatively affects replication.

Ultra-high pressure LC for astaxanthin determination in shrimp by-products and active food packaging.

Nowadays, there is increasing interest in natural antioxidants from food by-products. Astaxanthin is a potent antioxidant and one of the major carotenoids in crustaceans and salmonids. An ultra-high pressure liquid chromatographic method was developed and validated for the determination of astaxanthin in shrimp by-products, and its migration from new packaging materials to food simulants was also studied. The method uses an UPLC® BEH guard-column (2.1 × 5 mm, 1.7 µm particle size) and an UPLC® BEH analytical column (2.1 × 50 mm, 1.7 µm particle size). Chromatographic separation was achieved using a programmed gradient mobile phase consisting of (A) acetonitrile-methanol (containing 0.05 m ammonium acetate)-dichloromethane (75:20:5, v/v/v) and (B) ultrapure water. This method was evaluated with respect to validation parameters such as linearity, precision, limit of detection, limit of quantification and recovery. Low-density polyethylene films were prepared with different amounts of the lipid fraction of fermented shrimp waste by extrusion, and migration was evaluated into food simulants (isooctane and ethanol 95%, v/v). Migration was not detected under the tested conditions.

Comparison of oxidative stress and the frequency of polymorphisms in the HFE gene between hemoglobin S trait blood donors and sickle cell disease patients.

It is well documented that Hb S and iron affect blood cells, and trigger oxidative processes and generation of free radicals with potential for lipid peroxidation. We evaluated the frequency of polymorphisms in the HFE gene in Hb AS blood donors and how these polymorphisms influenced lipid peroxidation and antioxidant capacity. Blood samples were collected from 211 Hb AS blood donors, 119 Hb AA blood donors as a control group, and 28 sickle cell disease patients (Hb SS). The H63D allele was found at a frequency of 10.5% in the Hb AS samples, and the C282Y allele frequency was 0.7%. In the control group, the frequencies of the H63D and C282Y alleles were 13.4 and 2.1%, respectively. In the sickle-cell disease patients, the H63D and the C282Y allele frequencies were 10.7 and 3.5%, respectively. The frequencies of the C282Y and H63D polymorphisms in Hb AS blood donors are similar to those reported for the Brazilian population. Serum malondialdehyde values, indicative of lipid peroxidation, were highest in sickle cell patients, independent of the polymorphisms in the HFE gene, with significant differences, showing the influence of Hb S allele in the levels of lipid peroxidation. However, the trolox equivalent antioxidant capacity average levels, indicative of the antioxidant capacity, were reduced with significant differences, indicating that in spite of a lipid peroxidation raise, this is not followed by the increased of the antioxidant capacity, leading to oxidative stress.

[Percutaneous tibial nerve stimulation in urge urinary incontinence: A prospective study]. / Estimulación percutánea del nervio tibial en la incontinencia urinaria de urgencia: estudio prospectivo.

OBJECTIVE: To assess the efficacy of percutaneous tibial nerve stimulation and its effectiveness over time in urge urinary incontinence. MATERIALS AND METHODS: We performed a longitudinal, observational, prospective study without a control group that included patients diagnosed with urge urinary incontinence who met the inclusion/exclusion criteria. Patients were treated with 12 sessions of percutaneous tibial nerve stimulation by electroacupuncture. Baseline and post-treatment data were collected from medical records. Patients were assessed by a telephone interview after the treatment. The variables studied were sociodemographic variables, time until interview, the Sandvick and ICIQ-SF questionnaires, daytime urinary frequency, night-time urinary frequency, use of absorbent material and drug treatment. A descriptive analysis of the variables was performed and patient outcomes were analysed with generalised linear mixed models by SPSS v. 25 statistics software. RESULTS: A total of 32 women were included (mean age 58.69±8.96). All variables significantly improved after treatment: Sandvick by 4.38 points (95% CI: 2.68-6.08, P<.001), ICIQ-SF by 8.55 points (95% CI: 5.89-11.22, P<.001), daytime urinary frequency by 2.10 points (95% CI: 1.04-3.16, P<.001) and night-time urinary frequency by 1.31 points (95%CI: 0.58-2.04, P<.001). However, 16.34±9.72 months after treatment, these improvements diminished but without reaching baseline levels. CONCLUSIONS: Percutaneous tibial nerve stimulation by electroacupuncture is effective for the treatment of urge urinary incontinence. Although its effect diminishes over time, the improvement over the baseline situation is maintained during the follow-up period.

In Vivo Reflectance Confocal Microscopy: Emerging Role in Noninvasive Diagnosis and Monitoring of Eczematous Dermatoses. / Microscopia confocal de reflectancia in vivo: papel emergente en el diagnóstico no invasivo, así como en el seguimiento de las dermatosis eccematosas.

Dermatologic diagnosis and monitoring have been dependent largely on visual grading. A skin biopsy is performed in case of diagnostic uncertainty, but can be traumatic, and results are delayed due to time for specimen transport and processing. Biopsies also destroy specimens, prohibiting lesion evolution monitoring. In vivo reflectance confocal microscopy (RCM) offers a diagnostic alternative to skin biopsy. RCM captures real-time, high-resolution images, and has been piloted for the evaluation of various dermatologic conditions. Identification of unique RCM features may distinguish dermatoses with similar clinical morphologies. Allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) are diagnosed by patch testing that currently uses a subjective scoring system. RCM has increasingly been studied for early detection and severity grading of CD. Common RCM features shared by ACD and ICD are stratum corneum disruption, vesicle formation, exocytosis, spongiosis, and parakeratosis. Features unique to ACD are vasodilation, increased epidermal thickness, intercellular edema, and acanthosis. Features unique to ICD are detached corneocytes and targetoid keratinocytes. This review summarizes the use of RCM in evaluating contact eccematous conditions and aims to spark future research and interest in this promising tool.

Involvement of IFNbeta on IFNgamma and nitric oxide (NO) production by bone marrow (BM) cells in response to lipopolysaccharide.

Bone marrow (BM) cells fractioned in Percoll gradients yield a low-density fraction (Fr3) highly enriched in suppressor activity. Previously, it has been demonstrated that BM associated suppressor activity was mediated by early myeloid cells, through a mechanism dependent on endogenous IFNgamma and nitric oxide production after bacterial stimuli, e.g. lipopolysaccharide (LPS). However, the mechanism(s) through which the IFNgamma is produced in BM has not yet been fully elucidated. Therefore, in the present study we investigated the involvement of IL-12, IL-18 and IFNbeta on the production of IFNgamma and nitric oxide in cultures of BM Fr3 cells, and characterized the IFNgamma-producing cells, in response to LPS. The results show that both IL-12 and IFNbeta, but not IL-18, are involved on IFNgamma production. However, only IFNbeta appears to be critical on nitric oxide production. Furthermore, we found that cells of the Thy1.2+CD3+ phenotype produce IFNgamma and are tightly involved on nitric oxide production by BM Fr3 cells. In conclusion, IFNbeta appears to be critical on IFNgamma- and nitric oxide production by BM cells in response to LPS, through a mechanism that is dependent on Thy1.2+CD3+ IFNgamma-producing cells.

C/EBPß is required in pregnancy-induced cardiac hypertrophy.

AIM: Pregnancy is a physiological model of adaptive and reversible heart enlargement, but the molecular mechanisms determining this kind of physiologic cardiac hypertrophy are poorly known. Here, we analyzed the role of the transcription factor C/EBPß in the development of pregnancy-induced cardiac hypertrophy. RESULTS: C/EBPß+/- mice at day 18 of gestation were used as happloinsufficiency model of late pregnancy. We found that C/EBPß expression was specifically increased in hearts from Wt pregnant mice whereas expression of other C/EBP subtypes (α and δ) was not affected by gestation. Pregnancy-induced changes in systemic metabolic and hormonal profiles were not essentially different in Wt versus C/EBPß+/- mice. However, C/EBPß+/- mice developed pregnancy-induced heart hypertrophy to a lower extent relative to Wt mice. Furthermore, hearts from C/EBPß+/- mice have alterations in fatty acid oxidation genes and reductions in the expression levels of glucose transporters that may compromise metabolic cardiac function during pregnancy. Among marker genes of inflammation, interleukin-6 (Il-6) showed a marked differential behavior in C/EBPß+/- pregnant mice: pregnancy strongly induced cardiac Il-6 expression in wt, a phenomenon that did not occur in C/EBPß+/- mice. Moreover, marker genes for M2 macrophages were decreased in C/EBPß+/- pregnant mice and in C/EBPß-/- mice subjected to LPS stimulus. CONCLUSIONS: Here we found that normal levels of C/EBPß are required for hypertrophy development during pregnancy. Events such as the increase in IL-6 in the heart of pregnant mice are prevented in C/EBPß+/- animals. Moreover, C/EBPß controls M2-macrophage gene expression in the heart. Thus, C/EBPß appears as a transcription factor required for cardiac hypertrophy response to gestation.

Inhibition of bone marrow-derived natural suppressor activity by glucocorticoids and its reversal by IFN-gamma or IL-2.

Natural suppressor (NS) activity is mediated by cells (NS cells) of bone marrow origin with ability to suppress nonspecifically proliferative responses of lymphocytes. Here we show that pharmacologic concentrations (10(-6)-10(-8) M) of glucocorticoids (GC) greatly inhibit NS activity, as detected by coculturing bone marrow and spleen cells stimulated with B cell (LPS) or T cell (concanavalin A) mitogens. Progesterone antagonizes GC-mediated inhibition of NS activity, suggesting that GC were acting through a receptor-dependent mechanism. A prior treatment of NS cells with GC (10(-5) M) has no effect on the NS activity mediated by these cells. GC are required in culture during the first 24 hr of the suppressor assay. Addition of low amounts of IFN-gamma to GC-treated cultures fully reverses NS cell-mediated suppression. IL-2 produces a reversion as well, while addition of IL-3 or IL-4 does not prevent the GC effect. Neutralizing anti-IFN-gamma antibodies, but not anti-IL-2 or anti-TGF-beta, greatly inhibit NS activity in absence of GC. Taken together, these results indicate that GC inhibit NS activity by impairing endogenous cytokine production required to obtain successful NS cell activation, and not by acting directly on NS cells (i.e., inhibiting the secretion of putative NS factors). Among the cytokines involved in NS cell activation, IFN-gamma appears to be critical, since its addition readily overrides the GC effect and its neutralization results in strong inhibition of NS activity.

In vivo tissue characterization using magnetic techniques.

Among the few non-invasive methods to quantify liver iron deposits, magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS) have been considered the best to evaluate iron overload in the body. This diagnosis is necessary for patients who regularly receive red blood cells transfusion and that have a genetic disorder known as hemochromatosis. In this work, we present the evaluation of the clinical usefulness of MRI and BLS of hepatic tissue to quantify iron deposits in non-transfused and transfused patients. Liver iron evaluation by MRI and BLS were performed in a group of 48 patients. The MRI images weighted in T2 were acquired using multi-slice single-spin-echo (SSE) and single-slice multi-spin-echo (MSE), conducted on a 1.5 T whole body scanner. BLS measurements were performed using an ac superconducting susceptometer based on SQUID. Typically MRI is able to evaluate iron overload in liver as high as 30 mg/g(dry tissue) when using MRI scanners provided with specially designed pulse sequences. For higher iron concentrations susceptibility measurement works better than MRI to evaluate higher iron overloads in the liver, because in this case there is saturation of MRI signal.

Development of a low-cost, insect larvae-derived recombinant subunit vaccine against RHDV.

Vaccine antigens against rabbit hemorrhagic disease virus (RHDV) are currently derived from inactivated RHDV obtained from livers of experimentally infected rabbits. Several RHDV-derived recombinant immunogens have been reported. However, their application in vaccines has been restricted due to their high production costs. In this paper, we describe the development of an inexpensive, safe, stable vaccine antigen for RHDV. A baculovirus expressing a recombinant RHDV capsid protein (VP60r) was used to infect Trichoplusia ni insect larvae. It reached an expression efficiency of 12.5% of total soluble protein, i.e. approximately 2 mg of VP60r per larva. Preservation of the antigenicity and immunogenicity of the VP60r was confirmed by immunological and immunization experiments. Lyophilized crude larvae extracts, containing VP60r, were stable, at room temperature, for at least 800 days. In all cases, rabbits immunized with a single dose of VP60r by the intramuscular route were protected against RHDV challenge. Doses used were as low as 2 microg of VP60r in the presence of adjuvant or 100 microg without one. Orally administered VP60r in the absence of an adjuvant gave no protection. The potential costs of an RHDV vaccine made using this technology would be reduced considerably compared with producing the same protein in insect cells maintained by fermentation. In conclusion, the larva expression system may provide a broad-based strategy for production of recombinant subunit antigens (insectigens) for human or animal medicines, especially when production costs restrain their use.

Antierythrocyte antibodies in hemodialysis and kidney transplant patients.

Natural antierythrocytic antibodies may be stimulated by bacterial antigens and the immune type may occur as a result of pregnancy or blood transfusions. The prevalence increases with the number of red cell units transfused. Specificity, on the other hand, depends on ethnic backgrounds. The clinical importance of these antibodies is to precipitate hemolytic transfusion reactions and erythroblastosis fetalis. Hemodialysis patients are multitransfused and have a quite variable prevalence of antibodies. Kidney transplant patients with blood group identity do not form antibodies. We studied the presence of both types of antierythrocytic antibodies (natural and immune) in hemodialysis and kidney transplant patients in Brazilian blood transfusion and nephrology services.

Involvement of nitric oxide in bone marrow-derived natural suppressor activity. Its dependence on IFN-gamma.

Bone marrow (BM)-derived natural suppressor (NS) cells are strong inhibitors of lymphoproliferative responses. In this study we have assessed the involvement of nitric oxide (NO) in BM-derived NS activity, as detected in cocultures of BM and spleen cells stimulated with B cell (LPS) or T cell (Con A) mitogens. The results indicate that NS activity is readily inhibited by NG-monomethyl-L-arginine, a competitive inhibitor of NO synthase, or N-acetylcysteine, a free radical-scavenging thiol compound. High amounts of nitrite, a stable end product of NO, are detected only in supernatants of Con A- or LPS-stimulated spleen cells cocultured with BM cells enriched in NS activity (Fr3 cells). These amounts (15 to 55 microM) are strongly antiproliferative for both Con A and LPS responses, as was established with a nitrite curve made with a NO donor (sodium nitroprusside). Fr3 cells cultured alone release large quantities of NO and express inducible NO synthase (iNOS) mRNA upon LPS stimulation, but require spleen cells in cultures stimulated with Con A. Anti-IFN-gamma-neutralizing Abs blocked both NO production and NS activity, irrespective of the mitogen used; yet, only exogenous IFN-gamma is unable to promote successful NO production by Fr3 cells, but does induce detectable iNOS mRNA expression in these cells. Taken together the results indicate that: 1) NO is the major mediator of BM-derived NS activity; 2) BM cells enriched in NS activity produce large amounts of NO through an IFN-gamma-dependent iNOS induction.

Autoionization of homogeneous nickel(II) diphosphane hydrogenation catalysts. An NMR study and crystal structures of [Ni(o-MeO-dppe)I2] and [Ni(o-MeO-dppe)I2](PF6)2.

The synthesis of a number of nickel(II) complexes containing the didentate phosphane ligand 1,2-bis(di(o-methoxyphenyl)phosphino)ethane (o-MeO-dppe) is reported. Two types of complexes have been synthesized, i.e., the mono(chelate) complex (1) of the general formula [Ni(o-MeO-dppe)X2] (where X = Cl, Br or I) and the bis(chelate) complex (2) of the general formula [Ni(o-MeO-dppe)2]Y2 (where Y = PF6 or trifluoroacetate (TFA)). These complexes have been characterized using electronic absorption and NMR spectroscopy. The structures of the mono(chelate) complex [Ni(o-MeO-dppe)I2] (1c) and of the bis(chelate) complex [Ni(o-MeO-dppe)2](PF6)2 (2e) have been determined by X-ray crystallography. [Ni(o-MeO-dppe)I2] crystallizes in the monoclinic space group P2(1)/c with Z = 4, a = 12.1309(1) A, b = 16.5759(3) A, c = 17.6474(2) A, beta = 119.3250(10) degrees. [Ni(o-MeO-dppe)2](PF6)2 crystallizes in the monoclinic space group C2/c with Z = 4, a = 22.5326(3) A, b = 13.6794(2) A, c = 21.7134(3) A, beta = 107.1745(7) degrees. In both structures the nickel ion is in a square-planar geometry with a NiP2I2 and NiP4 chromophore, respectively. Using 1H and 31P[1H] NMR spectroscopy the behavior of the complexes in various solvents has been studied. It appears that in solution these nickel complexes are involved in an autoionization equilibrium: 2[Ni(o-MeO-dppe)X2] <==>[Ni(o-MeO-dppe)2](2+) + ["NiX(4)"](2-). The ionized complex (3) consists of a cationic unit in which a nickel atom is surrounded by two didentate phosphane ligands, and an anionic unit that stoichiometrically consists of a nickel atom and four anions. The position of the autoionization equilibrium is highly dependent on the anion and the solvent used. In a polar solvent in combination with weakly coordinating anions only the ionized complex is observed, whereas in an apolar solvent in combination with coordinating anions only the mono(chelate) complex occurs. A comparison of the behavior of o-MeO-dppe with its unsubstituted analogue dppe in combination with nickel(II) acetate using 31P[1H] NMR spectroscopy shows that the latter is more readily oxidized.

[Changes in blood lead, urinary alanine and coproporphyrins in workers exposed to high concentrations of environmental lead]. / Modificaciones de la plumbemia, alanuria y coproporfirinas en trabajadores expuestos a elevadas concentraciones de plomo ambiental.

A study was conducted on a total of 200 workers whose duties bring them into contact with lead, to determine levels of total alanuria, plumbemia and coproporphyrins in urine, basophil spotting and Burton's fringe. It was noted that in all cases these levels exceeded the maximum permitted environmental concentration. 80% (?) presented high figures for alanuria and 84% had very high plumbaemia levels. Coproporphyrins were also high in more than 60% and also in more than 60% of cases, basophil spotting was found. On the other hand, Burton's fringe was only detected in a few. Lastly, an important fact which emerged was the high rate of absenteeism among this group of workers.

Differential effects of transforming growth factor-beta 1 on IgA vs. IgG2b production by lipopolysaccharide-stimulated lymph node B cells: a comparative study with spleen B cells.

Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional cytokine that promotes IgA/IgG2b switching and secretion. Here, we show a differential effect of TGF-beta 1 on Ig production by lipopolysaccharide-stimulated spleen and lymph node (LN) B cells. Exogenous TGF-beta 1 increased IgA production in B cell cultures and IgG2b production by spleen B cells. In contrast, IgG2b was suppressed by TGF-beta 1 in cultures of LN B cells, although endogenous TFG-beta was required for IgG2b production in LN B cell cultures. The suppressor properties of exogenous TGF-beta 1 (0.5 ng/ml) on IgG2b production by LN B cells were also seen when testing IgG1 or IgG2a induced by interleukin-4 or interferon-gama, respectively. These differences between B cells from each lymphoid tissue appeared to be related to a different TGF-beta antiproliferative effect, since proliferation of LN B cells was extremely sensitive to TFG-beta 1 and IgG2b production was more sensitive than IgA to the TFG-beta-mediated suppression. However, by counteracting the antiproliferative effect of TGF-beta 1 with a CD40 agonistic mAb (IC10), the IgG2b response by LN B cells was still lacking. IC10 was nevertheless inhibitory for IgG2b production in most cases, while increasing secretion of IgA in the very same cultures. Taken together, the results suggest that functional differences between spleen and LN B cells do exit, at least with regard to the immunomodulating properties of TGF-beta on both proliferation and Ig production. Moreover, functional differences exist between cells committed for IgA and IgG2b regarding their sensitivity to the antiproliferative activity of TGF-beta 1 and the effect of CD40-derived signals on Ig secretion.

[Comparative study of blood lead and urine alanine in workers exposed to high concentrations of environmental lead]. / Estudio comparativo de la Plumbemia y la Alanuria en operarios expuestos a elevadas concentraciones de plomo ambiental.

The increase of the levels of lead in the blood and ALA in the urine in 40 workers whose jobs entail their coming into contact with lead salts has been studied over a four-year period, it having been observed that although the level of lead found in the blood varied in a majority of cases, it has been found to be approximately 30 micrograms per 100 ml, the ALA in the urine ranging around 0.40 mg per 100 ml. When these same workers were given medical checkups, no significant variations were found with regard to the type of work in which they were involved.

Early myeloid cells are high producers of nitric oxide upon CD40 plus IFN-gamma stimulation through a mechanism dependent on endogenous TNF-alpha and IL-1alpha.

Bone marrow contains nonadherent low-density wheat germ agglutinin-positive (Fr3-WGA(+)) cells that release large amounts of NO and show natural suppressor activity if stimulated with activated T cells. We have assessed the involvement of CD40-derived signals in NO production and their cytokine requirements. Production of NO by Fr3-WGA(+) cells in co-culture with activated T cells is inhibited by a competing CD40 soluble fusion protein. Fr3-WGA(+) cells express the inducible NO synthase (iNOS) and release NO following CD40 plus IFN-gamma activation. Production of NO through CD40 is strictly dependent on endogenous TNF-alpha and / or IL-1alpha, since it is inhibited by neutralizing these cytokines or blocking the TNF receptor (p55). Both cytokines are transcribed when Fr3-WGA(+) cells are stimulated by CD40 signaling plus IFN-gamma, although TNF-alpha remains below detection limits in stimulated Fr3-WGA(+) cell cultures. Phenotypic studies combined with data on intracellular iNOS expression and cell sorting indicate that NO-producing cells are CD40, CD31 (ER-MP12), CD11b (Mac-1)low, ER-MP20 (Ly-6C) and Gr-1 (Ly-6G) positive, consistent with myeloid progenitors. The results point to early myeloid cells as an important cell source of NO once triggered by activated T cells through CD40 and IFN-gamma-derived signals, in a mechanism involving the production of TNF-alpha and / or IL-1alpha.

Nitric oxide-producing CD11b(+)Ly-6G(Gr-1)(+)CD31(ER-MP12)(+) cells in the spleen of cyclophosphamide-treated mice: implications for T-cell responses in immunosuppressed mice.

During recovery from intensive chemotherapy with cyclophosphamide (CTX), mice suffer a severe but transitory impairment in spleen cell proliferation to T-cell mitogens (Con A or anti-CD3 plus IL-2). Although CTX treatment reduced spleen T-cell cellularity, this cannot fully account for T-cell unresponsiveness. The results showed that CTX induces the colonization of spleen by an immature myeloid CD11b(+)Ly-6G(+)CD31(+) population. Its presence closely correlated with the maximum inhibition of T-cell proliferation. Moreover, this suppressive activity was dependent on nitric oxide (NO) production in cultures since (1) higher amounts of nitric oxide and inducible nitric oxide synthase (iNOS) mRNA were produced in CTX spleen cells (CTX-SC) than in control splenocyte cultures and (2) NOS inhibitors greatly improved the proliferation of T lymphocytes. Nitric oxide production and suppressive activity were also dependent on endogenous interferon-gamma (IFN-gamma) production since anti-IFN-gamma abrogated both effects. Finally, iNOS protein expression was restricted to a heterogeneous population of CD31(+) cells in which CD11b(+)Ly-6G(+) cells were required to suppress T-cell proliferation. These results indicated that CTX might also cause immunosuppression by a mechanism involving the presence of immature myeloid cells with suppressor activity. This may have implications in clinical praxis since inappropriate immunotherapies in patients treated with intensive chemotherapy could lead to deleterious T-cell responses. (Blood. 2000;95:212-220)