Force and deformation stresses in customized and non-customized plates during simulation of advancement genioplasty.

PURPOSE: The aim of this study was to evaluate the distribution of deformation stresses in customized and non-customized plates during simulated advancement genioplasty, using the finite element method. METHODS: A customized plate (Traumec) was developed with 4.75 mm advancement, in ASTM F67 Grade 2 titanium, with four screws. Non-customized (standard) plates with 6 mm advancement (Stryker with six screws and Osteomed with four screws) were used for comparison. All the screws presented the same length (10 mm) and fixation system (2.0). The Traumec and Osteomed plates were fixed with two screws in the mandible, and another two in the segment, whereas the Stryker plate was fixed with three screws in the mandible, and another three in the segment. Six virtual models were generated in a computer-aided design program (Rhinoceros), in which the advancement and insertion of the plates were evaluated. All the plates were submitted to application of perpendicular and oblique forces of 5 N in the chin region. RESULTS: The Osteomed plate showed the highest stress value (1506 MPa), and the Traumec, the lowest stress value (560.20 MPa). The Stryker plate showed higher stress values for the segment screws than for the mandibular screws, unlike the other plates. CONCLUSIONS: The customized Traumec plate showed better deformation stress distribution and plate/segment stabilization when submitted to advancement genioplasty.

Circulating levels of immune and inflammatory markers and long versus short survival in early-stage lung cancer.

BACKGROUND: Some patients diagnosed with early-stage lung cancer and treated according to standard care survive for only a short period of time, while others survive for years for reasons that are not well understood. Associations between markers of inflammation and survival from lung cancer have been observed. MATERIALS AND METHODS: Here, we investigate whether circulating levels of 77 inflammatory markers are associated with long versus short survival in stage I and II lung cancer. Patients who had survived either <79 weeks (~1.5 years) (short survivors, SS) or >156 weeks (3 years) (long survivors, LS) were selected from a retrospective population-based study. Logistic regression was used to calculate adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs). The false discovery rate was calculated to adjust for multiple testing. RESULTS: A total of 157 LS and 84 SS were included in this analysis. Thirteen markers had adjusted OR on the order of 2- to 5-fold when comparing the upper and lower quartiles with regard to the odds of short survival versus long. Chemokine CCL15 [chemokine (C-C motif) ligand 15] was the most significant marker associated with increased odds of short survival (ORs = 4.93; 95% CI 1.90-12.8; q-value: 0.042). Smoking and chronic obstructive pulmonary disease were not associated with marker levels. CONCLUSIONS: Our results provide some evidence that deregulation of inflammatory responses may play a role in the survival of early-stage lung cancer. These findings will require confirmation in future studies.

Genetic variations of patients with familial or multiple melanoma in Southern Brazil.

BACKGROUND: Patients with familial melanoma or multiple primary melanoma represent a high-risk population to hereditary melanoma. Mutations in susceptibility genes, such as CDKN2A, CDK4 and MC1R, have been associated with the development of melanoma. OBJECTIVES: The purpose of this study was to determine the genotypic background of patients with familial and/or multiple melanoma in southern Brazil. METHODS: This study analysed 33 cases (5 patients with multiple primary melanoma and 28 patients from families with at least two well documented cases) and 29 controls. Genomic analysis of CDKN2A and CDK4 genes by PCR-SSCP analysis and sequencing and direct sequencing of MC1R were performed in all individuals. RESULTS: No functional mutations in CDKN2A or CDK4 were detected in the 62 individuals. Infrequent variants in polymorphic loci of CDKN2A gene were identified in 15 participants (24.2%) and 24/33 (72.8%) cases and 19/27 (70.4%) controls reported at least one infrequent variant in MC1R (P = 0.372). Furthermore, a non-significant tendency towards an association between melanoma risk and MC1R variants G274A and C451T and a non-significant linear tendency to the number of infrequent high-risk variants in MC1R were observed. CONCLUSIONS: These results suggest that in southern Brazilian population, CDKN2A or CDK4 germinal alterations may have a weaker influence than previously thought and environmental risk factors may play a central role in melanoma susceptibility. However, considering the tendency observed for gene MC1R, low-penetrance genes may be a relevant aetiological factor in southern Brazil with fair skin population and high sunlight exposure.

Efficacy of pentavalent antimony, amphotericin B, and miltefosine in Leishmania amazonensis-infected macrophages under normoxic and hypoxic conditions.

Recently, our group demonstrated that mouse lesions infected with Leishmania amazonensis are hypoxic. Evidence indicates the negative impact of hypoxia on the efficacy of a variety of chemotherapeutic agents against tumors, fungi, bacteria, and malaria parasites. In the present study, comparison of the effect of antileishmanial drugs on L. amazonensis-infected macrophages under normoxic and hypoxic conditions was performed. We compared the effect of 5% oxygen tension with a tension of 21% oxygen on peritoneal murine macrophage cultures infected with the parasite and treated with glucantime, amphotericin B, or miltefosine. Analysis of the infection index (percentage of infected macrophages x number of amastigotes per macrophage), dose-dependent efficacy of drugs, and IC(50) values demonstrated that hypoxia conferred a small, but significant, resistance to all 3 antileishmanial drugs. The present finding suggests that in vitro assays under hypoxia should not be neglected in drug studies.

Waldemiro Bazzanella: relembrando um amigo

Faleceu no Rio de Janeiro, onde vivia com a família, o professor Waldemiro Bazzanella. Não tenho nenhuma dúvida de que, para a maioria das pessoas, este nome não significa nada. Era "a face in the crowd"… Acontece que, para outros – e entre estes eu me incluo –, Bazzanella é alguém difícil de não ser lembrado, pela pessoa que era e pelo trabalho que realizou. Bazzanella morreu nos primeiros dias de fevereiro de 2002.

Host response to cytomegalovirus infection as a determinant of susceptibility to coronary artery disease: sex-based differences in inflammation and type of immune response.

BACKGROUND: Positive and negative associations between cytomegalovirus (CMV) infection and coronary artery disease (CAD) have been reported. We postulated that the susceptibility to CMV-induced CAD might relate to patterns of inflammatory and immune responses to CMV infection and that sex might have an effect on these responses. METHODS AND RESULTS: In 151 men and 87 women being evaluated for CAD, blood samples were tested for humoral (Ab+) and cellular (Tc+) responses to CMV and for C-reactive protein (CRP). In men, an elevated CRP level was a significant determinant of CAD even after adjustment for CAD risk factors (OR, 3.1; 95% CI, 1.21 to 7. 97). CMV seropositivity was associated with elevated CRP levels on multivariate analysis (P:=0.006). In contrast, in women, CMV seropositivity was independently predictive of CAD (OR, 41.8; 95% CI, 4.12 to 423.74). CRP level in women with CAD was >25% higher than those without CAD, but the difference did not reach statistical significance. Importantly, compared with CMV Ab-/Tc- women, CAD prevalence was higher in Ab+/Tc- and Ab+/Tc+ (13% versus 68% and 64%, both P:<0.005) but not in Ab-/Tc+ women (25%). There were no differences in age, smoking, diabetes, hypertension, and hypercholesterolemia among women with different types of immune responses to CMV infection. CONCLUSIONS: The mechanisms by which CMV predisposes to CAD in men and women may be different. In men, CMV appears to contribute to CAD risk, insofar as it predisposes to inflammation. In women, other mechanisms, possibly related to the type of immune response generated by the host, appear to be responsible for the proatherogenic effects of CMV.

Beta-chemokines inhibit activation-induced death of lymphocytes from HIV-infected individuals.

The present study investigates the role of the HIV-suppressive beta-chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1 and RANTES in activation-induced cell death (AICD). A pool of these beta-chemokines reduced anti-CD3-induced apoptosis of T cell blasts from healthy blood donors in a dose-dependent manner. Although the pooled beta-chemokines were more effective, the inhibitory effect could also be mediated by each of the individual chemokines and was blocked by neutralizing anti-chemokine antibodies. The beta-chemokines also inhibited pokeweed mitogen/staphylococcal enterotoxin B-induced T lymphocyte apoptosis in 33/49 HIV-infected (HIV+) individuals. This anti-apoptotic effect was not correlated with the patients' CD4 T cell counts. beta-chemokines did not lead to altered secretion of IL-2, IL-4, IFN-gamma or IL-10 in response to activation stimuli in either normal T cell blasts or peripheral blood mononuclear cells from HIV+ individuals. Co-incubation with beta-chemokines did not inhibit anti-CD3-induced expression of cell surface Fas ligand, nor did it alter levels of the death receptor Fas or Bcl-2 in T cell blasts, suggesting that the beta-chemokines are blocking AICD downstream of Fas. These observations indicate that beta-chemokines may play a novel role as modulators of AICD, in addition to their known role as chemoattractants and inhibitors of HIV replication.

Alloantigenic stimulation bypasses CD28-B7 costimulatory blockade by an interleukin-2-dependent mechanism.

Allogeneic leukocytes have been used as biological adjuvants for T cell-specific responses to tumor and recall antigens, but the mechanisms underlying this effect have not been fully understood. The present study investigates whether alloantigen stimulation of human T cells would bypass an in vitro T cell costimulatory dysfunction induced by CTLA4Ig blockage of CD28-B7 interaction. Here, we demonstrate that costimulation with intact allogeneic leukocytes plus viral antigen circumvented the inhibition of this costimulatory pathway via interleukin-2 (IL-2) production, resulting in the generation of influenza-specific cytotoxic T lymphocytes (CTL). The alloantigen-induced help for influenza-specific CTL generation did not require cell-to-cell contact between responding and allogeneic stimulator cells. These results suggest that alloantigens can be used to bypass defects in the CD28-B7 costimulatory pathway and, therefore, may contribute to understanding the mechanisms of alloantigen-induced restoration of T cell-mediated immunity.

HIV-specific immunity following immunization with HIV synthetic envelope peptides in asymptomatic HIV-infected patients.

OBJECTIVE: A phase I trial was conducted to evaluate the safety and immunogenicity of an HIV synthetic peptide vaccine in HIV-seropositive individuals. The immunogens used in this study were PCLUS 3-18MN and PCLUS 6.1-18MN envelope peptides. METHODS: Eight HIV-infected patients received six subcutaneous injections of 160 microg PCLUS 3-18MN in Montanide ISA 51 and were followed longitudinally for a year after the first immunization. Peripheral blood mononuclear cells (PBMC) were tested for peptide-specific T helper and cytotoxic T cell (CTL) responses, HIV-1MN neutralizing antibodies and antibodies against HIV PCLUS 3 and P18 MN peptides. RESULTS: PCLUS 3-1 8MN-specific T helper responses were significantly increased at 36 weeks (P < 0.05, after adjustment for multiple comparisons) following initial immunization with PCLUS 3-18MN. A P18MN-specific CTL response, not present prior to vaccination, was observed after immunization in one patient. Serum HIV-1 MN-neutralizing antibody titers increased in each of the three patients who had low titers prior to immunization. Plasma HIV RNA levels and CD4 cell counts did not change appreciably during the study period. CONCLUSIONS: This trial demonstrates that both peptides can be safely administered to HIV-infected individuals and that PCLUS 3-18MN induces increases in HIV peptide-specific immune responses.

Effect of zidovudine postexposure prophylaxis on the development of HIV-specific cytotoxic T-lymphocyte responses in HIV-exposed healthcare workers.

We evaluated the effects of zidovudine postexposure prophylaxis (PEP) on the development of human immunodeficiency virus (HIV) envelope-specific cytotoxic T-lymphocyte responses in 20 healthcare workers with occupational exposures to HIV. Seven healthcare workers were treated with zidovudine PEP. Only 1 of 7 treated, versus 6 of 13 not treated, developed an HIV envelope-specific cytotoxic T-lymphocyte response. These data suggest that zidovudine abrogated HIV-specific cytotoxic T-lymphocyte responses. HIV-specific cytotoxic T-lymphocyte responses may be useful as a surrogate marker of HIV replication in the evaluation of new regimens for PEP of occupational HIV exposures.

Alloimmunization for immune-based therapy and vaccine design against HIV/AIDS.

Recent studies have demonstrated protective effects of alloimmunization in the SIV model. Here, Gene Shearer, Ligia Pinto and Mario Clerici raise the possibility that alloimmunization against a spectrum of HLA-disparate leukocytes be considered for immune-based therapy and as an AIDS vaccine.

Alloantigen-stimulated anti-HIV activity.

A number of studies have suggested that an immune response to human leukocyte antigen (HLA) alloantigens may contribute to protection against HIV infection. In the present study, we examined the effect of alloantigen-stimulated cell lines obtained from peripheral blood mononuclear cells (PBMC) of HIV-uninfected (HIV-) individuals and the soluble factors produced by these cell lines on HIV-1 replication. Multiple in vitro restimulation with irradiated allogeneic PBMC from HIV- donors resulted in the expansion of CD8(+) T-cell lines that inhibited HIV-1 replication when cocultured with either autologous or heterologous in vitro-infected phytohemagglutinin (PHA) blasts. Supernatants from the alloantigen-stimulated cell lines also inhibited HIV replication in both PHA blasts and a chronically infected cell line. The alloantigen-stimulated cell lines and the factors they produced inhibited both T-cell-tropic (T) and macrophage-tropic (M) isolates of HIV-1. Blocking experiments using anti-chemokine antibodies suggested that this inhibition of HIV replication was not due to the beta-chemokines present in cocultures of cell lines with HIV-infected blasts. These results indicate that alloantigen-stimulation of PBMC from HIV- individuals activates CD8(+) T cells that produce soluble factor(s) that inhibit HIV replication of a wide spectrum of HIV-1 isolates through a chemokine-independent mechanism. This is a US government work. There are no restrictions on its use.

HIV-1 infection induces a selective reduction in STAT5 protein expression.

HIV-1 infection is accompanied by qualitative and quantitative defects in CD4+ T lymphocytes. Loss of immune function in HIV patients is usually associated with a profound dysregulation of cytokine production. To investigate whether cytokine signaling defects occur during HIV infection, PHA blasts from healthy human donors were infected with two strains of HIV-1 and screened for the expression of STAT proteins used in cytokine signaling. A selective decrease in STAT5B was seen 8 days after infection with the BZ167 dual-tropic HIV isolate, but not with the Ba-L, M-tropic strain. Based on these findings, purified T cells from HIV-infected patients in different stages of disease were also tested for STAT expression; decreases in STAT5A, STAT5B, and STAT1alpha were observed in all patients. The reduction in STATs seen in vivo and in vitro after HIV infection may contribute to the loss of T cell function in HIV disease.

Effects of substance P on human T cell function and the modulatory role of peptidase inhibitors.

Evidence has been presented for a modulatory role of surface peptidases on substance P-mediated immune responses. In this study, we first characterized the effects of substance P and its carboxy- and amino-terminal fragments on human lymphocyte proliferative responses to investigate whether peptidase inhibitors influence the effects of the neuropeptide. Substance P at 10(-7) M and the carboxy-terminal fragment SP(4-11) slightly enhanced the lymphocyte responses to phytohemagglutinin and concanavalin A. In contrast, the amino-terminal fragment SP(1-4) failed to have any positive effect. However, in the presence of dipeptidylpeptidase IV/CD26 and neutral endopeptidase/CD10 inhibitors (diprotin A and thiorphan, respectively), the effect of substance P on mitogen-induced proliferation was significantly increased. These data support the hypothesis that lymphocyte surface peptidases play a modulatory role in the effects of substance P on T cell function.

T-helper reactivity to simian immunodeficiency virus gag synthetic peptides in human immunodeficiency virus type 2 infected individuals.

West African populations are infected with divergent strains of human immunodeficiency virus type 2 (HIV2), some of which are closely related to simian immunodeficiency virus (SIV) and it has been postulated that the HIV2 epidemic might have arisen by cross-species spread of SIV into the human population in West Africa. To gain some insight into the possible basis for cross protection between these two closely related viruses, the T-helper responses to 15 synthetic peptides from SIV gag synthetic peptides were investigated in seven HIV2-infected subjects and in seven healthy controls. Significant reactivity to at least one of the synthetic peptides tested was found in all patients and a statistically significant correlation between CD4+ lymphocyte absolute numbers and the number of reacting peptides was observed. A marginal lymphocyte reactivity was found in two of the healthy controls studied. In conclusion, this preliminary evidence that HIV2-infected patients exhibit T-cell responses to SIV gag peptides suggests that both viruses share t-helper epitopes in the gag viral region and raises the possibility of cross protection between SIV and HIV2 which may be relevant for HIV2 vaccine research based on closely related retroviruses.

ENV-specific cytotoxic T lymphocyte responses in HIV seronegative health care workers occupationally exposed to HIV-contaminated body fluids.

Identification of the components of protective immunity are crucial for the development of effective prophylactic and therapeutic vaccine strategies. Analysis of HIV-specific responses in exposed but uninfected individuals might thus provide a unique resource to elucidate the components and correlates of protective immunity to HIV. In the present study we analyzed HIV-specific cytotoxic and helper T lymphocyte responses in health care workers (HCW) exposed to body fluids from HIV-positive individuals. HCW exposed to blood from HIV-negative individuals as well as healthy donors served as controls. Cytotoxic T lymphocyte (CTL) responses to HIV envelope (env) peptides were detected in 7/20 (35%) HCW exposed to HIV-positive blood and in none of the 20 health care workers exposed to uninfected blood or the seven healthy blood donors studied. HIV-specific CTL responses were detected only after in vitro stimulation, and were MHC class I restricted. No MHC class I restriction elements were uniformly identified among the different responders. 21/28 (75%) HCW exposed to contaminated blood responded to env as measured by IL-2 production to the peptides, in contrast to only 9/38 (24%) HCW exposed to HIV seronegative blood and 3/35 (9%) healthy blood donors. All the HIV exposed individuals were seronegative on repeated ELISA tests, and no evidence of infection was obtained by PCR analysis. These findings indicate that a single exposure to HIV can induce CTL immunity to HIV antigens, in the absence of other evidence of infection.

Restoration of HIV-specific cell-mediated immune responses by interleukin-12 in vitro.

Peripheral blood mononuclear cells (PBMCs) from many asymptomatic individuals infected with human immunodeficiency virus-type 1 (HIV) are unresponsive as measured by in vitro T cell proliferation and interleukin-2 (IL-2) production to influenza virus and synthetic peptides of HIV envelope (Env). Strong influenza virus- and Env-stimulated IL-2 responses and T cell proliferation were restored when cultures were stimulated in the presence of IL-12. Interferon-gamma production by PBMCs from HIV seropositive (HIV+) patients was also restored with IL-12. Furthermore, in vitro antigen-specific production of IL-2 and proliferation of PBMCs from HIV- donors were suppressed by antibody to IL-12, but were not enhanced by addition of exogenous IL-12. Thus, IL-12 may be limiting in PBMCs from HIV+ but not HIV- individuals. These findings demonstrate that IL-12 can restore HIV-specific cell-mediated immunity in vitro in HIV-infected individuals and suggest a potential use of IL-12 in augmenting the diminished immunologic functions associated with HIV infection.